WO2024095111A1 - Battery control system and vehicle - Google Patents

Battery control system and vehicle Download PDF

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Publication number
WO2024095111A1
WO2024095111A1 PCT/IB2023/060835 IB2023060835W WO2024095111A1 WO 2024095111 A1 WO2024095111 A1 WO 2024095111A1 IB 2023060835 W IB2023060835 W IB 2023060835W WO 2024095111 A1 WO2024095111 A1 WO 2024095111A1
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WO
WIPO (PCT)
Prior art keywords
battery
positive electrode
circuit
active material
electrode active
Prior art date
Application number
PCT/IB2023/060835
Other languages
French (fr)
Japanese (ja)
Inventor
長多剛
塚本洋介
小野谷茂
片桐治樹
Original Assignee
株式会社半導体エネルギー研究所
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Publication of WO2024095111A1 publication Critical patent/WO2024095111A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L50/00—Electric propulsion with power supplied within the vehicle
    • B60L50/50—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells
    • B60L50/60—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells using power supplied by batteries
    • B60L50/64—Constructional details of batteries specially adapted for electric vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L9/00—Electric propulsion with power supply external to the vehicle
    • B60L9/16—Electric propulsion with power supply external to the vehicle using ac induction motors
    • B60L9/18—Electric propulsion with power supply external to the vehicle using ac induction motors fed from dc supply lines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries

Definitions

  • the present invention relates to a battery control system or a vehicle equipped with a battery control system.
  • the present invention is not limited to the above technical fields, but also relates to an electronic device equipped with a battery control system.
  • the present invention also relates to a power storage device equipped with a battery control system.
  • power storage devices include stationary power storage devices.
  • Secondary batteries have become indispensable in modern society as a reusable energy source.
  • a secondary battery that has lithium ions as the carrier ion is called a lithium-ion secondary battery or lithium-ion battery.
  • secondary batteries are referred to as batteries, and unless otherwise specified, batteries do not include primary batteries.
  • An electric vehicle is a vehicle that runs on a motor powered by electricity stored in a battery.
  • a battery pack (a collection of multiple single cells) is used as the battery.
  • Batteries are often mounted on a vehicle body housed in a container (also called a battery pack). By housing the battery in a container, it is possible to separate the battery from other vehicle components, making it easier to manage the temperature of the battery.
  • a structure has been proposed in which the battery is fixed to the vehicle chassis without being housed in a container (also called a cell-to-chassis structure) (see Patent Document 1).
  • a battery fixed to the vehicle chassis as in Patent Document 1 above has the problem that the battery is more susceptible to temperature effects and degradation than a battery pack.
  • one aspect of the present invention provides a battery and a battery control system with a new configuration to suppress battery deterioration.
  • Another aspect of the present invention provides an in-vehicle battery equipped with a new battery to suppress deterioration of a battery fixed to a vehicle chassis.
  • a further aspect of the present invention provides a battery control system that controls two or more batteries as described above. Note that when the battery fixed to the vehicle chassis is referred to as the first battery, the new battery may be referred to as the second battery.
  • both the first battery and the second battery may be mounted on the vehicle as a battery pack.
  • One aspect of the present invention is a battery control system that includes a first battery having a first positive electrode active material, a second battery having a second positive electrode active material, a first sensor circuit electrically connected to the first battery, a second sensor circuit electrically connected to the second battery, a first DC/DC converter electrically connected to the first battery, a second DC/DC converter electrically connected to the second battery, and a microcomputer electrically connected to the first sensor circuit, the second sensor circuit, the first DC/DC converter, and the second DC/DC converter, and the microcomputer has a function of determining the output from the first DC/DC converter to the motor control circuit and the output from the second DC/DC converter to the motor control circuit based on a signal obtained from the first sensor circuit or the second sensor circuit.
  • Another aspect of the present invention is a battery control system having a first battery having a first positive electrode active material, a second battery having a second positive electrode active material, a first sensor circuit electrically connected to the first battery, a second sensor circuit electrically connected to the second battery, a first DC/DC converter electrically connected to the first battery, a second DC/DC converter electrically connected to the second battery, a microcontroller electrically connected to the first sensor circuit, the second sensor circuit, the first DC/DC converter, and the second DC/DC converter, and a protection IC electrically connected to the microcontroller, the microcontroller having a function of determining the output from the first DC/DC converter to the motor control circuit and the output from the second DC/DC converter to the motor control circuit based on a signal obtained from the first sensor circuit or the second sensor circuit.
  • a battery management system having a microcontroller and a protection IC.
  • the protection IC is electrically connected to a single cell of the first battery or a single cell of the second battery.
  • the first positive electrode active material has an olivine type crystal structure
  • the second positive electrode active material has a layered rock salt type crystal structure
  • the battery further includes a first circuit and a second circuit, the first circuit being located between the first battery and the charging control circuit, and the second circuit being located between the second battery and the charging control circuit, and the first circuit and the second circuit preferably having a function of transferring power from the first battery to the second battery.
  • the battery further includes a first circuit and a second circuit, the first circuit being located between the first battery and the charging control circuit, the second circuit being located between the second battery and the charging control circuit, and the first circuit and the second circuit preferably having a function of transferring power from the second battery to the first battery.
  • the first sensor circuit preferably has a first current sensor electrically connected to a single cell of the first battery.
  • the first sensor circuit preferably has a first voltage sensor electrically connected to a single cell of the first battery.
  • the second sensor circuit preferably has a second current sensor electrically connected to a single cell of the second battery.
  • the second sensor circuit preferably has a second voltage sensor electrically connected to a single cell of the second battery.
  • the microcontroller has a function of controlling the output of the first DC/DC converter and the output of the second DC/DC converter based on the dQ/dV curve of the first battery.
  • the microcontroller has a function of controlling the output of the first DC/DC converter and the output of the second DC/DC converter based on the dQ/dV curve of the second battery.
  • Another aspect of the present invention is a vehicle equipped with a battery control system.
  • the battery control system which is one aspect of the present invention, can suppress battery deterioration.
  • FIGS. 1A to 1D are diagrams illustrating a vehicle and a battery control system according to one embodiment of the present invention.
  • FIG. 2 is a diagram illustrating the configuration of a quick charging stand.
  • FIG. 3 is a diagram illustrating a battery control system according to an embodiment of the present invention.
  • 4A and 4B are diagrams illustrating a BMS according to one embodiment of the present invention.
  • FIG. 5 is a diagram illustrating a battery control system according to an embodiment of the present invention.
  • FIG. 6 is a diagram illustrating a battery control system according to an embodiment of the present invention.
  • FIG. 7 is a graph showing the characteristics of a battery used in the battery control system according to one embodiment of the present invention.
  • FIG. 8A and 8B are graphs of dQ/dV curves of a battery used in a battery control system according to one embodiment of the present invention.
  • FIG. 9 is a graph of the dQ/dV curve of a battery used in a battery control system according to one embodiment of the present invention.
  • FIG. 10 is a flowchart for explaining the procedure of the battery control system according to one embodiment of the present invention.
  • FIG. 11 is a flowchart for explaining the procedure of the battery control system according to one embodiment of the present invention.
  • FIG. 12 is a flowchart for explaining the procedure of the battery control system according to one embodiment of the present invention.
  • 13A and 13B illustrate a positive electrode which is one embodiment of the present invention.
  • FIG. 14 is a diagram illustrating a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
  • FIG. 15 is a diagram illustrating a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
  • FIG. 16 is a diagram illustrating a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
  • 17A to 17C illustrate a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
  • 18A to 18C illustrate a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
  • FIG. 19 is a diagram illustrating a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
  • 20A to 20C illustrate a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
  • 21A and 21B are diagrams illustrating a battery that is one embodiment of the present invention.
  • 22A and 22B are diagrams illustrating a laminated battery cell according to one embodiment of the present invention.
  • 23A and 23B are diagrams illustrating a method for manufacturing a laminated battery cell according to one embodiment of the present invention.
  • 24A to 24C are diagrams illustrating a rectangular battery cell according to one embodiment of the present invention.
  • 25A to 25C are diagrams illustrating a rectangular battery cell according to one embodiment of the present invention.
  • 26A to 26D are diagrams illustrating a cylindrical battery cell according to one embodiment of the present invention.
  • 27A to 27C are diagrams illustrating a vehicle according to one embodiment of the present invention.
  • FIG. 28 is a diagram illustrating power transfer between a vehicle and a house according to one embodiment of the present invention.
  • vehicle chassis refers to components other than the body of the vehicle, including the frame, etc.
  • a battery pack has multiple single cells and can be said to be an assembly of single cells.
  • battery pack refers to the battery pack housed in a container.
  • the container can be made of plastic or metal, but plastic is a better material in terms of weight reduction and/or heat insulation.
  • battery pack may also be used when the container contains one or more components selected from a battery management system (referred to as "BMS") that monitors the battery pack and a cooling mechanism for the battery pack, that is, when components other than the battery pack are housed in the container.
  • BMS battery management system
  • the BMS has a function to prevent overcharging and over-discharging of the cells.
  • the BMS also has a function to prevent overcurrent in the cells.
  • the BMS also has a function to manage the temperature of the cells.
  • the BMS also has a function to calculate the remaining charge (SOC: State of Charge) of the cells. The remaining charge may be interpreted as the charging rate or charging state.
  • the BMS also has a function to equalize the voltage of each cell in the battery pack (this is called cell balancing).
  • a BMS with one of these functions can also be said to be a system that performs safety control.
  • the SOC is an index that can be calculated from the voltage of a single cell.
  • the SOC may be expressed as a percentage, with the upper limit charge state being 100% and the lower limit discharge state being 0%, and SOC 50% means that the voltage has been halved from the upper limit charge state.
  • the temperature of the single cell which may be read as the temperature of the exterior body of the single cell
  • room temperature typically 25°C
  • the SOC may be an index calculated from the capacity of the single cell. When the capacity is used, it can also be expressed as a percentage, with the upper limit charge state being 100% and the lower limit discharge state being 0%.
  • deterioration of a battery includes deterioration due to charge/discharge cycles and deterioration that occurs without exposure to charge/discharge cycles.
  • a battery that has a discharge capacity of 97% or more of its rated capacity can be said to be in a state before deterioration.
  • the materials contained in the single cell positive electrode active material, negative electrode active material, electrolyte, etc. will be described in terms of their state before deterioration.
  • a battery control system according to one embodiment of the present invention is mounted on a vehicle.
  • Vehicles on which the battery control system according to one embodiment of the present invention can be mounted include electric vehicles (EVs) and plug-in hybrid vehicles (PHVs), and the electric vehicle will be used for the description.
  • EVs electric vehicles
  • PSVs plug-in hybrid vehicles
  • the battery control system according to one embodiment of the present invention can also be mounted on, for example, electronic devices or power storage devices other than vehicles.
  • an electric vehicle 11 has a battery 101, a charging port 19, tires 13, and a headlight 23.
  • the battery 101 may have two or more batteries, and will be described using a first battery 101a and a second battery 101b.
  • the battery control system will be described assuming that the battery forms a battery pack.
  • the battery pack can function as a single large-capacity battery or a single high-voltage battery by combining the electrodes of multiple single cells.
  • the capacity or voltage can be adjusted to an appropriate value by connecting multiple single cells in series and in parallel.
  • the present invention is not limited to battery packs, and the battery control system can be understood by replacing the battery pack with single cells.
  • the battery control system is preferably installed in an electronic device or a power storage device.
  • FIG. 1B shows the state in which the first battery 101a is fixed to the vehicle chassis.
  • the single cells 51 of the first battery 101a are fixed to the chassis 27.
  • the single cells 51 can be configured as rectangular battery cells, which will be described later.
  • the single cells 51 can be configured as laminated battery cells or cylindrical battery cells, which will be described later.
  • the first battery 101a does not have a container, so it can be lightweight and low-cost.
  • the second battery 101b is provided as shown in FIG. 1A and the like.
  • the first battery 101a fixed to the vehicle chassis is greatly affected by water from rain, etc., it is preferable to use a battery with high safety.
  • FIG 1C shows a battery pack that houses the second battery 101b. It is preferable to use a battery pack consisting of multiple battery packs 52 as the second battery 101b, and in Figure 1C, the battery pack 52 is housed in a container 28.
  • the battery pack 52 has single cells, and the single cells can have the laminated battery cell configuration described below. Of course, the single cells can also have the rectangular battery cell or cylindrical battery cell configuration described below.
  • the container of the battery pack 52 can be made of plastic or metal.
  • the battery pack 52 is illustrated with a portion of the container 28 omitted. This configuration makes it possible to insulate the battery pack 52 from heat outside the container 28, i.e., from the external temperature.
  • the second battery 101b can perform temperature management with precision, providing an environment that is less prone to deterioration.
  • the battery pack is considered to be easy to replace.
  • the above-mentioned second battery 101b corresponds to a newly installed battery and functions as an auxiliary to the first battery 101a.
  • the second battery 101b suppresses deterioration of the first battery 101a and can extend the cycle life (also simply referred to as life) of the first battery 101a.
  • life also simply referred to as life
  • the first battery 101a does not need to be replaced during the period until the electric vehicle 11 is scrapped.
  • the frequency of replacement of the first battery 101a can be reduced.
  • the first battery 101a fixed to the vehicle chassis is configured to be difficult to replace compared to a battery pack, it can be said that the improvement of the life of the first battery 101a has a significant effect.
  • the first battery 101a which is to be prevented from deteriorating, should be mounted farther away from the motor than the auxiliary second battery 101b. In other words, it is preferable to place the first battery 101a, which is to be prevented from deteriorating, away from the motor, which can be a heat source.
  • the above-mentioned auxiliary relationship can be satisfied, and deterioration of at least the first battery 101a can be suppressed.
  • the first battery 101a does not need to be fixed to the vehicle chassis, and may be housed in, for example, a battery pack. In other words, in one embodiment of the present invention, all of the two or more batteries may be housed in a battery pack.
  • the first battery 101a is preferably a cell that is safer than the second battery 101b.
  • the positive electrode active material may be appropriately selected.
  • the electrolyte, the negative electrode active material, and the separator material may be appropriately selected.
  • a cell with high safety can be realized by a composite oxide having an olivine crystal structure (also called a phosphate compound having an olivine crystal structure) containing iron ( Fe ), manganese ( Mn ), cobalt (Co) or nickel (Ni) in addition to lithium (Li), such as lithium iron phosphate (LiFePO 4 ), lithium manganese phosphate (LiMnPO 4 ), lithium cobalt phosphate (LiCoPO 4 ), and lithium nickel phosphate (LiNiPO 4 ).
  • a composite oxide having an olivine crystal structure also called a phosphate compound having an olivine crystal structure
  • iron ( Fe ), manganese ( Mn ), cobalt (Co) or nickel (Ni) in addition to lithium (Li), such as lithium iron phosphate (LiFePO 4 ), lithium manganese phosphate (LiMnPO 4 ), lithium cobalt phosphate (LiCoPO 4 ), and lithium nickel phosphate (Li
  • the above-mentioned positive electrode active material having an olivine structure has a very small structural change due to charging and discharging, and has a stable crystal structure, as compared with, for example, a positive electrode active material having a layered rock salt type crystal structure. Therefore, it is stable even against operations such as overcharging, and when used as a positive electrode active material, a highly safe unit cell can be realized.
  • the second battery 101b is preferably a single cell that can be charged at a higher voltage than the first battery 101a.
  • the positive electrode active material may be appropriately selected.
  • the electrolyte, the negative electrode active material, and the separator material may be appropriately selected.
  • phosphate compounds having a layered rock salt structure such as lithium cobalt oxide (also referred to as LCO), lithium nickel-cobalt-manganese oxide (also referred to as NCM), lithium nickel-cobalt-aluminate (also referred to as NCA), and lithium nickel-manganese-aluminate (also referred to as NMA), can be cited as examples of materials that enable high-voltage charging.
  • Phosphate compounds having a layered rock salt structure have good cycle characteristics and enable high-voltage charging because lithium ions can move two-dimensionally between layers consisting of MO 6 octahedra when the transition metal M is used.
  • lithium cobalt oxide is a suitable material for high-voltage charging because it is possible to suppress phase changes during high-voltage charging by adding an additive element.
  • the additive element may be one or more selected from the group consisting of magnesium, aluminum, nickel, fluorine, and titanium.
  • the additive elements contained in the positive electrode active material are explained below.
  • Magnesium ions one of the added elements, are divalent, and magnesium ions are more stable at the lithium site than at the cobalt site in the layered rock-salt crystal structure, so they tend to enter the lithium site.
  • the presence of magnesium at an appropriate concentration at the lithium site in the surface layer makes it easier to maintain the layered rock-salt crystal structure even during high-voltage charging.
  • Aluminum one of the added elements, can exist at the cobalt site in the layered rock salt crystal structure. Since aluminum is a typical element and its valence does not change from trivalent, lithium around the aluminum is difficult to move even during charging and discharging. Therefore, aluminum and the lithium around it function as pillars, which can suppress changes in the crystal structure. Aluminum also has the effect of suppressing the dissolution of surrounding cobalt and improving continuous charging resistance.
  • Nickel one of the additive elements, can exist in both the cobalt site and the lithium site.
  • nickel exists in the lithium site, it can suppress the shift of the layered structure consisting of octahedra of cobalt and oxygen. It also suppresses the change in volume caused by charging and discharging.
  • nickel exists in the cobalt site, it is preferable because it leads to an increase in discharge capacity because its redox potential is lower than that of cobalt.
  • Fluorine ions which are one of the additive elements, are monovalent anions, and when part of the oxygen in the surface layer of the positive electrode active material is replaced by fluorine, the lithium desorption energy is reduced. This is because the valence of the cobalt ion changes with lithium desorption from trivalent to tetravalent in the absence of fluorine, and from divalent to trivalent in the presence of fluorine, resulting in different redox potentials. Therefore, when part of the oxygen in the surface layer of the positive electrode active material is replaced by fluorine, it can be said that desorption and insertion of lithium ions near the fluorine occurs more smoothly. Therefore, when used in a secondary battery, the charge/discharge characteristics, current characteristics, etc. can be improved.
  • Titanium oxide one of the additive elements, is known to have superhydrophilicity, so by forming a cathode active material having titanium oxide on the surface layer thereof, it is possible that the cathode active material may have good wettability with highly polar solvents.
  • the combination of two or more batteries may use batteries with different battery characteristics.
  • the battery characteristics of the first battery 101a may be different from the battery characteristics of the second battery 101b.
  • Parameters that contribute to the battery characteristics include capacity and voltage. Therefore, the capacity (mAh/g) of the second battery 101b may be made larger than the capacity (mAh/g) of the first battery 101a. Since the capacity is a parameter that depends on the weight of the active material, the above capacity may be read as the capacity value of a single battery in the combination of two or more batteries.
  • the output characteristics of the second battery 101b may be made higher than the output characteristics of the first battery 101a.
  • the output characteristics of the combination of two or more batteries may be read as the upper limit voltage of the battery.
  • the combination of two or more batteries may be mounted on a vehicle in different ways, for example, a combination of a battery fixed to a vehicle chassis as shown in FIG. 1B and a battery pack as shown in FIG. 1C may be used.
  • the charging port 19 of the electric vehicle 11 has at least a normal charging port 19a, and may also have a rapid charging port 19b.
  • FIG. 1D shows a block diagram of an electric vehicle 11 including a battery control system 10 according to one embodiment of the present invention.
  • the electric vehicle 11 has a Vehicle Control Unit (hereinafter referred to as VCU) 21 and a Controller Area Network (hereinafter referred to as CAN) 25.
  • VCU 21 may receive an accelerator signal and/or a brake signal, and has a function of controlling the display inside the vehicle.
  • the CAN 25 is electrically connected to the VCU 21 and can receive GPS signals.
  • the CAN 25 can be electrically connected to the battery control system 10, etc.
  • the headlights 23 and other components can be operated using an auxiliary battery 24.
  • the auxiliary battery 24 can be a secondary battery (e.g., a lead battery).
  • the auxiliary battery 24 is sometimes called a 12V battery because of its operating voltage.
  • the electric vehicle 11 has a normal charging port 19a that is electrically connected to the charging control circuit 12 via a converter (also called an on-board charger) 18.
  • the converter 18 has a conversion device such as an AC/DC circuit, and has the function of converting alternating current from the charging station to direct current. During normal charging, the process of converting alternating current to direct current is performed on the electric vehicle 11 side. Therefore, normal charging may take a long time.
  • FIG. 2 illustrates a charging stand 30 that enables quick charging.
  • the charging stand 30 is electrically connected to an AC power source 31 and has a large-scale circuit for converting AC current to DC current.
  • the circuit includes a converter 33, an inverter 34, a transformer circuit 35, and a rectifier circuit 36, which are electrically connected to each other as shown in FIG. 2. It is preferable that a high-frequency insulating transformer is applied to the transformer circuit 35.
  • the relationship in which a signal from the inverter 34 is input to the transformer circuit 35 and a signal from the transformer circuit 35 is output to the rectifier circuit 36 is called a functional connection, and in this specification, the functional connection is included in the electrical connection.
  • Charging is possible by inserting a connector 37 provided on the charging stand 30 into the charging port 19b for quick charging.
  • the above circuitry can process the current at high speed, shortening the charging time during rapid charging.
  • charging the battery using DC current i.e., rapid charging
  • setting an upper limit on the current can increase safety. Note that the electric vehicle 11 does not need to be equipped with a rapid charging port 19b.
  • the charge control circuit 12 which is electrically connected to the converter 18 or the quick charge port 19b, is electrically connected to the battery control system 10. In other words, a signal from the charge control circuit 12 becomes one of the input signals to the battery control system 10. Signals from other circuits may also be input to the battery control system 10.
  • the battery control system 10 has at least a first battery 101a, a second battery 101b, and a BMS 150.
  • the BMS 150 functions as at least a safety control system, and has a microcomputer 150a and a protection IC 150b as shown in FIG. 3. Furthermore, when the BMS 150 is installed in an electric vehicle, the BMS 150 needs to execute the above-mentioned system while the vehicle is traveling. Therefore, it is preferable to transmit information regarding the mileage and remaining mileage to the BMS 150 at any time. Details of the BMS 150 and the battery control system 10 will be described later using FIG. 3 and FIG. 4, etc.
  • the battery control system 10 is electrically connected to a motor control circuit 14.
  • the motor control circuit 14 is also called an inverter, and may be integrated with a drive motor 15 and mounted on a vehicle.
  • the motor control circuit 14 has a function of converting DC current from the first battery 101a and/or the second battery 101b into AC current (three-phase AC). Furthermore, the motor control circuit 14 has a function of controlling the drive motor 15 in response to accelerator operation.
  • the drive motor 15 is connected to the tire 13 and can rotate the tire 13 using the power discharged from the first battery 101a and/or the second battery 101b.
  • the drive motor 15 has the function of converting the power from the battery into rotational force.
  • a permanent magnet or an electromagnet is used for the drive motor 15.
  • the maximum voltage of the drive motor 15 is preferably high, 300V or more and 800V or less, and preferably 400V or more and 800V or less.
  • the discharge rate of the first battery 101a and/or the second battery 101b may be determined according to the rotation speed of the tire 13, i.e., the accelerator operation.
  • a transmission also called a gearbox
  • the transmission has the function of transmitting power from the drive motor 15 to the tires 13 in response to accelerator operation.
  • the rotation speed of the drive motor 15 needs to be increased, but the rotation speed of the tires 13 is low.
  • the transmission plays a role in balancing the drive motor 15 and the tires 13 when starting as described above.
  • An integrated motor control circuit 14, drive motor 15, and transmission is called an electric axle, and electric axles are sometimes installed on vehicles.
  • the battery control system 10 has at least a first battery 101a, a second battery 101b, and a BMS 150.
  • the BMS 150 has at least a microcomputer 150a and a protection IC 150b, and receives information on the current, voltage, temperature, etc. related to the single battery. Information on the current, voltage, temperature, etc. related to the battery pack can also be estimated using the microcomputer 150a, etc.
  • the battery control system 10 can use the microcomputer 150a without adding a new control circuit. Calculations related to the battery control system 10 do not place a burden on the processing of the CPU (Central Processing Unit) of the microcomputer 150a. Of course, the battery control system 10 may also be operated using a control circuit other than the microcomputer 150a.
  • CPU Central Processing Unit
  • FIG 4A shows an example of software that can be operated by the microcomputer 150a.
  • the microcomputer 150a may be equipped with voltage monitoring software 151, SPC calculation software 152, insulation resistance detection software 153, current detection software 154, temperature adjustment control 155, CAN software 156, and relay sequence software 157.
  • Each of the above-mentioned software is electrically connected to the CAN 25 in Figure 1D, etc. so as to be able to send and receive signals.
  • Figure 4B shows an example of a circuit diagram for the protection IC 150b.
  • the protection IC 150b has a first protection IC 150bx(1) and an nth protection IC 150bx(n), where n is an integer equal to or greater than 2.
  • the first protection IC 150bx(1) is electrically connected to the single cell 1a(1) of the first battery 101a.
  • the nth protection IC 150bx(n) is electrically connected to the single cell 1a(n) of the first battery 101a. In this way, it is advisable to prepare a number of protection ICs 150b according to the number of single cells.
  • the protection IC 150b further includes a first protection IC 150by(1) and an mth protection IC 150by(m), where m is an integer of 2 or more.
  • the first protection IC 150by(1) is electrically connected to the single cell 1b(1) of the second battery 101b.
  • the mth protection IC 150by(m) is electrically connected to the single cell 1b(m) of the second battery 101b. In this way, it is advisable to prepare a number of protection ICs 150b according to the number of single cells.
  • m can be an integer equal to n, an integer less than n, or an integer greater than n.
  • the protection IC 150b makes it possible to control each cell based on the calculation results from each software.
  • the battery control system 10 has a first circuit 106a, a second circuit 106b, a first DC/DC circuit (including a DC/DC converter) 107a, a second DC/DC circuit (including a DC/DC converter) 107b, a first sensor circuit 102a, and a second sensor circuit 102b. All of the above-mentioned circuits are electrically connected to each other as shown in FIG. 3 so as to enable transmission and reception of signals with the BMS 150.
  • the electrical connection between the BMS 150 and the first sensor circuit 102a and the second sensor circuit 102b may be made using bus wiring.
  • Signals for controlling the first DC/DC circuit 107a and the second DC/DC circuit 107b can be generated using a control circuit in the battery control system 10, but as described above, it is preferable to use the microcomputer 150a in the BMS 150 to determine the outputs from the first DC/DC circuit 107a and the second DC/DC circuit 107b. Specifically, the output signal from the BMS 150 can control the switches in the first DC/DC circuit 107a and the second DC/DC circuit 107b. Depending on the operation of the switch, the first DC/DC circuit 107a and the second DC/DC circuit 107b can each make the output voltage higher or lower than the input voltage.
  • the output of the battery control system 10 is electrically connected to the motor control circuit 14, and a diode may be placed between them.
  • the diode can prevent the power from the first battery 101a from being supplied to the second battery 101b and the power from the second battery 101b from being supplied to the first battery 101a.
  • a first diode 108a is electrically connected between the first DC/DC circuit 107a and the output
  • a second diode 108b is electrically connected between the second DC/DC circuit 107b and the output.
  • the first sensor circuit 102a and the second sensor circuit 102b may each have a voltage sensor and/or a current sensor.
  • the first sensor circuit 102a has a first voltage sensor 103a and a first current sensor 104a
  • the second sensor circuit 102b has a second voltage sensor 103b and a second current sensor 104b.
  • the first voltage sensor 103a has a function of measuring the voltage of the first battery 101a
  • the first voltage sensor 103a and the first battery 101a are electrically connected to each other so that this is possible
  • the second voltage sensor 103b has a function of measuring the voltage of the second battery 101b
  • the second voltage sensor 103b and the second battery 101b are electrically connected to each other so that this is possible.
  • the first current sensor 104a has a function of measuring the current of the first battery 101a, and the first current sensor 104a and the first battery 101a are electrically connected to enable this.
  • the second current sensor 104b has a function of measuring the current of the second battery 101b, and the second current sensor 104b and the second battery 101b are electrically connected to enable this.
  • the measured current value is for when the battery is being charged and/or discharged, and the measured voltage value is for when the battery is being charged and/or discharged.
  • the first voltage sensor 103a is electrically connected to each cell in the first battery 101a, allowing the voltage of each cell to be measured.
  • the second voltage sensor 103b is electrically connected to each cell in the second battery 101b, allowing the voltage of each cell to be measured.
  • the battery control system 10 can measure time by adding a counter circuit or the like. It is also possible to calculate the capacity value of the battery by integrating the time and the current value.
  • the first sensor circuit 102a and the second sensor circuit 102b may each have a coulomb counter. The coulomb counter makes it possible to measure the integrated capacity of the first battery 101a and/or the second battery 101b in addition to the current value and voltage value.
  • the microcomputer 150a of the BMS 150 receives data on current values, voltage values, capacity values (including integrated capacity), etc. from the first sensor circuit 102a and the second sensor circuit 102b, and is able to estimate the deterioration of the single battery. It is more preferable to perform a calculation based on dQ/dv to estimate the deterioration.
  • Such a microcomputer 150a can control the first DC/DC circuit 107a and the second DC/DC circuit 107b in response to the deterioration of the battery, etc.
  • the battery control system 10 can suppress deterioration by further including a first circuit 106a and a second circuit 106b.
  • the circuit configurations of the first circuit 106a and the second circuit 106b will be described with reference to Fig. 5. Note that since the second circuit 106b has a similar circuit configuration to the first circuit 106a, the description of the second circuit 106b may be simplified.
  • the first circuit 106a has a switch (hereinafter referred to as switch SW) 11 that controls the transmission of input signals to the first circuit 106a and the second circuit 106b.
  • the first circuit 106a has a transformer 22a and a switch SW.
  • the first circuit 106a has at least two switches SW, specifically, a switch SW26a and a switch SW25a.
  • an insulating transformer is used for the transformer 22a.
  • One side of the transformer 22a may be referred to as the primary side circuit of the transformer 22a, and the other side may be referred to as the secondary side circuit of the transformer 22a.
  • the primary side circuit has a coil Wa1, one end of which is electrically connected to the switch SW12, and the other end is electrically connected to the switch SW25a.
  • the switch SW12 is also electrically connected to the first battery 101a.
  • the secondary circuit of the transformer 22a also has a coil Wa2 and a switch SW26a, with one end of the coil Wa2 electrically connected to the switch SW11 and the other end electrically connected to the switch SW26a.
  • the magnetic field generated from that coil generates an induced electromotive force in the other coil, for example coil Wa2.
  • This phenomenon is sometimes called mutual induction.
  • a voltage is induced in the other coil, for example coil Wa2, and a current flows through coil Wa2.
  • the number of turns in coil Wa1 is the same as the number of turns in coil Wa2, but the numbers of turns may be different.
  • the first circuit 106a it is preferable to use switching elements such as MOS transistors for the switches SW25a and SW26a.
  • switching elements such as MOS transistors for the switches SW25a and SW26a.
  • a resistive element may be electrically connected to the switch SW25a in order to rectify.
  • a resistive element may be electrically connected to the switch SW26a. The timing at which the current caused by the induced electromotive force flows can be controlled by turning the switches SW25a and SW26a on and off.
  • the second circuit 106b has a configuration similar to that of the first circuit 106a. However, in the second circuit 106b, one end of the coil Wb1 is electrically connected to the switch SW13. The switch SW13 is also electrically connected to the second battery 101b.
  • the switch SW11 When each battery is charged, the switch SW11 is turned on to use the first circuit 106a and/or the second circuit 106b as a flyback converter or a forward converter. Specifically, when the first battery 101a is charged, the switch SW11 is turned on to use the first circuit 106a as a flyback converter or a forward converter. When the second battery 101b is charged, the switch SW11 is turned on to use the second circuit 106b as a flyback converter or a forward converter.
  • a period A in which only the first battery 101a is charged and a period B in which only the second battery 101b is charged can be provided. In this case, the period A is preferably before the period B.
  • the first battery 101a and the second battery 101b may be charged simultaneously.
  • the first circuit 106a is used as a flyback converter.
  • the switch SW26a is controlled to be on and the switch SW25a is controlled to be off, and a current is passed through the coil Wa2 via the switch SW11.
  • the generated magnetic flux magnetizes the iron core (also referred to as the core) around which the coil Wa2 is wound.
  • the magnetization of the core is sometimes referred to as the accumulation of energy, and energy can be stored in the core when the switch SW26a is turned on.
  • a current flows through the coil Wa1, and the energy accumulated in the core is released.
  • the first battery 101a can be charged via the switch SW12.
  • the number of turns of the coil Wa1 may be different from the number of turns of the coil Wa2. By making the number of turns different, it is also possible to make the input voltage and output voltage of the first circuit 106a different. Also, to reduce energy loss, it is a good idea to use a silicon steel laminate for the core.
  • the process for charging the second battery 101b is similar to that for charging the first battery 101a.
  • the first circuit 106a may also be used as a forward converter.
  • the battery control system 10 having the first circuit 106a and the second circuit 106b is capable of transferring the power of one of the first battery 101a and the second battery 101b to the other.
  • the case where the power of the second battery 101b is transferred to the first battery 101a will be described with reference to Fig. 6.
  • Fig. 6 shows the circuit configuration shown in Fig. 5 with arrows (Xa, Ya, Xb, and Yb) indicating the direction of current.
  • switches SW25b and SW13 are controlled to be turned on, and the capacity to be transferred is extracted from the second battery 101b.
  • an arrow Yb is added to the current from the second battery 101b flowing through coil Wb1 of transformer 22b.
  • the current flowing as indicated by the arrow Yb is sometimes referred to as I (discharge).
  • the capacity to be transferred from the second battery 101b can be determined according to the deterioration of the first battery 101a.
  • the capacity to be transferred can also be determined according to the SOC of the first battery 101a.
  • a current corresponding to I(return) flows through the coil Wa2 of the transformer 22a of the first circuit 106a.
  • the current flowing through the coil Wa2 is indicated by an arrow Xa, and the current flowing as indicated by the arrow Xa is sometimes referred to as I(supply), also known as the supply of charge.
  • I(supply) also known as the supply of charge.
  • the current indicated by the arrow Xa has the same value as the current indicated by the arrow Xb. However, slight losses may occur in the above current due to components.
  • the first circuit 106a and the second circuit 106b enable the charging and transfer of power to each battery.
  • the frequency of use of the first battery 101a can be reduced, deterioration of the first battery 101a can be suppressed, and the lifespan of the first battery 101a can be improved. If the first battery 101a is fixed to the vehicle chassis, it is possible to reduce the frequency of replacement.
  • ⁇ Characteristic 1 of the Battery Control System By using the battery control system 10 described above, it is possible to select a battery that will provide the main output during a period X when the electric vehicle 11 starts to travel and during a period Y when the electric vehicle 11 has had sufficient travel time. Appropriate selection can suppress deterioration of the first battery 101a. For example, when outputs from the first battery 101a and the second battery 101b are utilized during the period X when the electric vehicle 11 starts to travel, the second battery 101b is selected as the battery that will provide the main output.
  • the burden on the first battery 101a can be reduced and deterioration of the first battery 101a can be suppressed.
  • the battery can have a high output density per weight or volume. Therefore, by making the second battery 101b the battery that is responsible for the main output during the driving start period X, it is possible to increase the capacity of the battery 101.
  • Period Y when the electric vehicle 11 has sufficient running time the battery responsible for the main output may be switched from the second battery 101b to the first battery 101a.
  • Period Y when the running time is sufficient includes, for example, a period when the tire rotation speed becomes constant.
  • Whether it is the above-mentioned period X or period Y may be determined based on time. Alternatively, it is also possible to determine whether it is the above-mentioned period X or period Y based on an accelerator signal and/or a brake signal from the VCU 21.
  • the BMS 150 can further determine the main output battery by adding the SOC, deterioration state, and estimated values of the first battery 101a and the second battery 101b. After the main output battery is determined, the first DC/DC circuit 107a and the second DC/DC circuit 107b can be controlled by a signal from the BMS 150 to determine the main output battery.
  • the charge/discharge rate of the first battery 101a can be made constant.
  • the first battery 101a is prone to deterioration when exposed to a high charge rate such as rapid charging and the rate fluctuates frequently, but by controlling the charge rate to be constant, deterioration of the first battery 101a can be suppressed.
  • Whether the rate fluctuates more frequently due to exposure to a high charging rate such as rapid charging may be determined based on time. Alternatively, it is also possible to determine whether the rate fluctuates more frequently due to exposure to a high charging rate such as rapid charging based on a signal from the charging control circuit 12.
  • the BMS 150 can further determine the SOC, degradation state, and estimated values of the first battery 101a and the second battery 101b, as well as the charge/discharge rate of the first battery 101a or the second battery 101b.
  • Regenerative charging refers to charging the battery 101 by using the drive motor 15 as a generator during deceleration, downhill driving, or the like. Since regenerative charging is likely to cause deterioration of the battery, in regenerative charging, the rate at which the second battery 101b is charged is increased compared to the rate at which the first battery 101a is charged, and further, during regenerative charging, only the second battery 101b is charged, thereby suppressing deterioration of the first battery 101a.
  • Whether to perform regenerative charging can be determined based on the accelerator signal and/or brake signal from the VCU 21. After making the above determination, the BMS 150 can also determine the battery to be used for regenerative charging by adding the SOC, deterioration state, and estimated values of the first battery 101a and the second battery 101b.
  • Calendar deterioration is one type of battery deterioration, and refers to deterioration that occurs without exposure to charge/discharge cycles, that is, deterioration that occurs even when the battery is not used. It is said that calendar deterioration is likely to progress when the battery's SOC is high, so deterioration of the first battery 101a can be suppressed by transferring power to the second battery 101b so that the SOC of the first battery 101a is less than 100%, preferably 90% or less, and more preferably 80% or less.
  • Whether or not a situation in which calendar degradation may occur may be determined based on time. After making the above determination, it is preferable for the BMS 150 to further determine the SOC, degradation state, and estimated values of the first battery 101a and the second battery 101b, as well as the power to be transferred from each battery.
  • the BMS 150 includes the microcomputer 150a and the like, and therefore, in addition to adjusting the cell balance, for example, it is possible to grasp the state of the single battery and estimate deterioration. While internal resistance and the like can be used to estimate deterioration, the estimation accuracy can be improved by using the following data.
  • the data may be dQ/dV, which is the ratio of the change in charge (also written as the amount of electricity) (dQ) to the change in voltage (dV) of the single cells of the first battery 101a and the second battery 101b.
  • dQ/dV the ratio of the change in charge (also written as the amount of electricity) (dQ) to the change in voltage (dV) of the single cells of the first battery 101a and the second battery 101b.
  • dQ/dV can be obtained when the first battery 101a and/or the second battery 101b are being charged. It is also possible to obtain dQ/dV each time the SOC changes, such as SOC 50% and SOC 60%.
  • dQ/dV When dQ/dV is plotted on a graph, it may form a curve, which is sometimes referred to as a dQ/dV curve.
  • a dQ/dV curve one or more peaks can be identified, and these peaks can be called the maximum values present in the curve. Of the two or more peaks, the one with the highest intensity can be called the maximum value.
  • the dQ/dV curves of each cell are stored and can be compared with past data. This comparison can be used to estimate the deterioration of the cells. In addition, because the deterioration can be estimated, it is possible to predict when to replace the second battery 101b, etc.
  • OCV Open Circuit Voltage
  • OCV/V indicates the ratio of the voltage (V) during discharge to the OCV.
  • the graph shown in Figure 7 shows OCV/V (V) versus SOC (%).
  • Characteristic 01 is the characteristic exhibited by the first battery 101a
  • characteristic 02 is the characteristic exhibited by the second battery 101b.
  • the plateau region there is a flat region in the change of OCV/V (V) when the SOC is 10% or more and 90% or less, and this region is called a plateau region.
  • the plateau region may occur when lithium iron phosphate ( LiFePO4 ) is used as the positive electrode active material, and the plateau region is a state in which LiFePO4 and FePO4 coexist.
  • Characteristic 02 is characterized by a continuous change in OCV/V(V), and a higher OCV/V(V) than characteristic 01.
  • LCO or NCM is a good choice for a positive electrode active material that exhibits such characteristics.
  • Figures 8A and 8B are examples of dQ/dV curves of a single cell that can be applied to the first battery 101a.
  • Figures 8A and 8B can be said to be dQ/dV curves calculated from characteristic 01 in Figure 7.
  • arrows are shown at the first peak to the third peak for ease of understanding.
  • Figure 8A is a dQ/dV curve for OCV/V, and the first peak is confirmed when the voltage is 3.3V or more and 3.4V or less, and the second peak is confirmed when the voltage is more than 3.4V and 3.5V or less.
  • Figure 8B is a dQ/dV curve for integrated capacity, and the third peak is confirmed when the integrated capacity is 480mAh or more and 620mAh or less.
  • the changes are clearer than in Figure 7, and peaks are confirmed in the range that is often used as the output voltage of the first battery 101a, or in the range of integrated capacity.
  • the peak position shifts or the peak intensity increases or decreases, so this data can be easily used to estimate deterioration.
  • Figure 9 is an example of a dQ/dV curve of a battery that can be applied to the second battery 101b.
  • the charge/discharge cycle numbers for the second battery 101b are superimposed when they are 1 (referred to as cycle number 1 in the figure) and 400 (referred to as cycle number 400 in the figure).
  • graphite is used for the negative electrode of the second battery 101b.
  • arrows are shown at the peak (1) of the negative electrode and the peak (2) of the positive electrode for ease of understanding. From Figure 9, it can be seen that the peak (1) of the negative electrode is confirmed at a voltage of 3.6V or more and 3.8V or less, and the peak intensity of the negative electrode decreases as the cycle number increases from 1 to 400.
  • the data on which the graph shown in FIG. 7 is based can be obtained by the first sensor circuit 102a and the second sensor circuit 102b, and dQ/dV can be calculated by the microcomputer 150a. It is preferable to obtain the data from the first sensor circuit 102a and the second sensor circuit 102b every time charging, as this allows for highly accurate estimation.
  • the above-mentioned data may be stored in the cloud via the CAN 25 or the like. Furthermore, the above-mentioned data or degradation estimates, etc. may be made viewable from an electronic device linked to the electric vehicle 11.
  • the BMS 150 can control the output of the first battery 101a and/or the second battery 101b. Specifically, the BMS 150 controls the first DC/DC circuit 107a and/or the second DC/DC circuit 107b based on a control signal from the BMS 150.
  • the battery control system 10 may include a temperature sensor.
  • the temperature sensor may be provided at a position where the temperature of the battery 101 can be detected.
  • a thermistor may be used as the temperature sensor. A contact portion of the thermistor is brought into contact with the battery 101, and a change in the resistance value of the contact portion is detected to calculate the temperature of the battery 101.
  • the battery 101 may be replaced with a first battery 101a and a second battery 101b.
  • step S53 charging of the first battery 101a is started first.
  • step S54 the charging current of the first battery 101a is detected using the first current sensor 104a.
  • step S55 the charging voltage of the first battery 101a is detected using the first voltage sensor 103a. Note that the order of steps S54 and S55 may be reversed, or they may be detected in the same step. After that, as shown in step S56, charging of the first battery 101a is terminated.
  • step S57 the microcomputer 150a calculates dQ/dV using the current value and voltage value. After that, as shown in step S58, a comparison is made with dQ/dV in past charging, and as shown in step S59, the deterioration of the first battery 101a is estimated.
  • the charging of the second battery 101b can be started as shown in step S61.
  • the second battery 101b may be charged before the first battery 101a.
  • the first battery 101a and the second battery 101b may be charged in the same step.
  • the charging current of the second battery 101b is detected using the second current sensor 104b as shown in step S62.
  • the charging voltage of the second battery 101b is detected using the second voltage sensor 103b as shown in step S63. Note that the order of steps S62 and S63 may be reversed, or they may be detected in the same step.
  • the charging of the second battery 101b is terminated as shown in step S64.
  • step S65 the BMS 150 calculates dQ/dV using the current value and voltage value. Then, as shown in step S66, a comparison is made with dQ/dV from previous charging, and as shown in step S67, the state of the second battery 101b is estimated.
  • step S71 the connector is removed from the normal charging port 19a, and then the electric vehicle 11 starts traveling as shown in step S72.
  • step S73 in FIG. 11 the second battery 101b is discharged at the start of traveling.
  • the life of the first battery 101a can be extended.
  • step S74 it is determined whether the deterioration of the first battery 101a estimated by the BMS 150 should be tolerated, and if appropriate, discharging from the first battery 101a is started as shown in step S75.
  • Discharging from the second battery 101b may be stopped, or discharging of the first battery 101a may be performed in the same step as discharging of the second battery 101b. If the deterioration of the first battery 101a is not tolerated, discharging from the second battery 101b is continued as shown in step S76.
  • step S77 the electric vehicle 11 is parked.
  • step S81 of FIG. 12 it is determined whether the parking period of the electric vehicle 11 is longer or shorter than the period (D) in which calendar deterioration begins to occur.
  • the period (D) can be determined by the VCU 21, the CAN 25, or the BMS 150. If it is determined that the parking period is longer than the period (D) in which calendar deterioration occurs, as shown in step S82, the transfer of power between the first battery 101a and the second battery 101b is started so that the SOC of the first battery 101a is such that deterioration is unlikely to occur. After the transfer, the SOC of the first battery 101a can be less than 100%, preferably 90% or less, and more preferably 80% or less.
  • step S81 Even if it is determined in step S81 that the period is equal to or less than the period (D), when a signal Dx that switches to a mode that takes calendar deterioration into consideration is transmitted from an electronic device linked to the electric vehicle 11, such as a smartphone, to the CAN 25 or the BMS 150 as shown in step S83, transfer between the first battery 101a and the second battery 101b can be started as shown in step S82 so that the SOC of the first battery 101a becomes a value that is less susceptible to calendar deterioration.
  • step S84 the electric vehicle 11 can start traveling.
  • the battery control system makes it possible to suppress deterioration of the first battery 101a.
  • [Positive electrode] 13A shows an example of a cross-sectional view of a positive electrode of a single cell.
  • the positive electrode has a positive electrode active material layer 571 on a positive electrode current collector 550.
  • the positive electrode active material layer 571 has a positive electrode active material 561, a positive electrode active material 562, a conductive material 553, a conductive material 554, and a gap.
  • the gap is impregnated with an electrolyte 556.
  • the positive electrode active material layer 571 also has a binder (binding agent).
  • Positive electrode active material 561 is an example of a positive electrode active material having a larger median diameter (D50) than positive electrode active material 562. By using positive electrode active materials having different median diameters (D50), it is possible to increase the tap density of the positive electrode active material.
  • Conductive material 553 is an example of a conductive material having a different shape from conductive material 554. Conductive material 553 is preferably in the form of particles, and conductive material 554 is preferably in the form of a sheet or fiber.
  • the positive electrode current collector 550 may be made of a material having high electrical conductivity, specifically, metals such as copper, gold, platinum, aluminum, iron, or titanium, and alloys of the above metals. Stainless steel may be used as an iron alloy.
  • the positive electrode current collector 550 may be made of a metal or alloy that does not dissolve at the potential of the positive electrode.
  • the positive electrode current collector 550 may be made of an aluminum alloy to which an element that improves heat resistance, such as silicon, titanium, neodymium, scandium, or molybdenum, is added.
  • the positive electrode current collector 550 may be made of a metal that reacts with silicon to form a silicide, such as the above titanium.
  • Metal elements that react with silicon to form a silicide include, in addition to the above titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, or nickel.
  • the thickness of the positive electrode collector 550 is preferably 5 ⁇ m to 30 ⁇ m, more preferably 10 ⁇ m to 20 ⁇ m, and may be in the form of a sheet or plate.
  • the positive electrode collector 550 may be subjected to punching or expanded metal processing.
  • the punching metal processing is a punching process
  • the expanded metal processing is a process in which cuts are made and the material is stretched.
  • the positive electrode collector 550 becomes a mesh-like material with circular, elliptical, or diamond-shaped openings.
  • FIG. 13A shows a positive electrode active material 561 and a positive electrode active material 562, which are sometimes called positive electrode active material particles.
  • the shape of the positive electrode active material may be various shapes other than particulate.
  • the cross-sectional shape of the positive electrode active material 561 may be elliptical, rectangular, trapezoidal, pyramidal, rectangular with rounded corners, or asymmetrical.
  • the particulate positive electrode active material may be deformed into the shape shown in FIG. 13B by pressing in the positive electrode manufacturing process.
  • Other configurations in FIG. 13B are the same as those in FIG. 13A.
  • the positive electrode active material 561 and the positive electrode active material 562 may be either primary particles or secondary particles.
  • a primary particle refers to a particle (lump) that is the smallest unit that does not have grain boundaries when observed at, for example, 5000 times magnification using a SEM (scanning electron microscope) or the like, and is sometimes called a single particle.
  • a secondary particle refers to a particle (particle independent of others) in which the primary particles are aggregated so as to share part of the grain boundary (such as the outer periphery of the primary particle). In other words, a secondary particle has a grain boundary.
  • the positive electrode active material 561 and the positive electrode active material 562 can be made of a material capable of inserting and removing carrier ions.
  • the carrier ions can be lithium ions, sodium ions, potassium ions, calcium ions, strontium ions, barium ions, beryllium ions, or magnesium ions.
  • Materials capable of inserting and extracting lithium ions include lithium composite oxides having an olivine type crystal structure, a layered rock salt type crystal structure, or a spinel type crystal structure.
  • LiFePO 4 When Fe is used as M, it is represented as LiFePO 4 , which may be written as LFP.
  • LFP may be written as a composite oxide having lithium, iron, and phosphorus, and may have elements other than the exemplified elements, and further elements that do not contribute to the capacity. Since LFP is highly safe, it is preferable to use it for the first battery 101a.
  • the surface layer refers to a region up to 50 nm from the surface of the active material, preferably up to 30 nm, and more preferably up to 10 nm.
  • LiNi x Co y Mn z O 2 (x>0, y>0, 0.8 ⁇ x+y+z ⁇ 1.2).
  • LiNi x Co y Mn z O 2 (x>0, y>0, 0.8 ⁇ x+y+z ⁇ 1.2) may be written as NCM.
  • NCM may be referred to as a lithium composite oxide having Ni, Co, and Mn, or may be referred to as a composite oxide having Li, Ni, Co, and Mn.
  • the NCM may also contain one or more elements selected from calcium, boron, gallium, aluminum, boron, and indium at a concentration of 0.1 atomic % or more and 3 atomic % or less.
  • the above concentrations of calcium, boron, gallium, aluminum, boron, and indium may be referred to as additive elements.
  • the additive element is preferably located in the surface layer of the active material. In the case of secondary particles, the additive element is preferably located at the grain boundary.
  • materials capable of inserting and desorbing sodium ions include NaFeO2 , NaNiO2 , NaCoO2 , NaMnO2 , NaVO2 , Na( NiXMn1-X ) O2 (0 ⁇ X ⁇ 1 ), Na( FeXMn1 -X ) O2 (0 ⁇ X ⁇ 1), NaVPO4F , Na2FePO4F , and Na3V2 ( PO4 ) 3 .
  • the binder is provided so that the positive electrode active material 561, the positive electrode active material 562, the conductive material 553, and the conductive material 554 do not slip off from the positive electrode collector 550.
  • the binder also plays a role of binding the positive electrode active material 561 and the conductive material 553.
  • the binder also plays a role of binding the positive electrode active material 562 and the conductive material 553.
  • the binder also plays a role of binding the positive electrode active material 561 and the conductive material 554.
  • the binder also plays a role of binding the positive electrode active material 562 and the conductive material 554.
  • binders positioned so as to contact the positive electrode collector 550, those positioned between the positive electrode active material 561 and the conductive material 553 or the conductive material 554, those positioned between the positive electrode active material 562 and the conductive material 553 or the conductive material 554, those positioned so as to be entangled with the conductive material 553, and those positioned so as to be entangled with the conductive material 554.
  • the binder it is preferable to use a rubber material such as styrene-butadiene rubber (SBR), styrene-isoprene-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, or ethylene-propylene-diene copolymer.
  • SBR styrene-butadiene rubber
  • fluororubber can be used as the binder.
  • a water-soluble polymer as the binder.
  • polysaccharides can be used as the water-soluble polymer.
  • cellulose derivatives such as carboxymethyl cellulose (CMC), methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, and regenerated cellulose, or starch can be used as the polysaccharide. It is even more preferable to use these water-soluble polymers in combination with the above-mentioned rubber material.
  • binder it is preferable to use materials such as polystyrene, polymethyl acrylate, polymethyl methacrylate (polymethyl methacrylate, PMMA), sodium polyacrylate, polyvinyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide, polyimide, polyvinyl chloride, polytetrafluoroethylene, polyethylene, polypropylene, polyisobutylene, polyethylene terephthalate, nylon, polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), ethylene propylene diene polymer, polyvinyl acetate, and nitrocellulose.
  • PVA polyethylene oxide
  • PEO polypropylene oxide
  • polyimide polyvinyl chloride
  • PVDF polytetrafluoroethylene
  • PVDF polyvinylidene fluoride
  • PAN polyacrylonitrile
  • ethylene propylene diene polymer polyvinyl acetate, and nitrocellulose.
  • the binder may be a combination of a material with a particularly excellent viscosity adjustment effect and another material.
  • a material with a particularly excellent viscosity adjustment effect For example, while rubber materials have excellent adhesive strength and elasticity, it may be difficult to adjust the viscosity when mixed with a solvent. In such cases, it is preferable to mix the binder with a material with a particularly excellent viscosity adjustment effect.
  • a water-soluble polymer may be used as a material with a particularly excellent viscosity adjustment effect.
  • the above-mentioned polysaccharides for example, carboxymethylcellulose (CMC), methylcellulose, ethylcellulose, hydroxypropylcellulose, and diacetylcellulose, cellulose derivatives such as regenerated cellulose, or starch may be used.
  • CMC carboxymethylcellulose
  • methylcellulose methylcellulose
  • ethylcellulose methylcellulose
  • hydroxypropylcellulose hydroxypropylcellulose
  • diacetylcellulose cellulose derivatives such as regenerated cellulose, or starch
  • the solubility of cellulose derivatives such as carboxymethylcellulose can be increased by converting them into salts such as sodium salt or ammonium salt of carboxymethylcellulose, making them more effective as viscosity adjusters. Increasing the solubility can also increase the dispersibility with the active material or other components when preparing the electrode slurry.
  • the cellulose and cellulose derivatives used as electrode binders include their salts.
  • Water-soluble polymers stabilize the viscosity by dissolving in water, and can stably disperse the active material and other materials to be combined as a binder, such as styrene-butadiene rubber, in an aqueous solution.
  • a binder such as styrene-butadiene rubber
  • they are expected to be easily and stably adsorbed onto the surface of the active material.
  • cellulose derivatives such as carboxymethyl cellulose, have functional groups such as hydroxyl groups or carboxyl groups, and because they have functional groups, the polymers are expected to interact with each other and widely cover the surface of the active material.
  • the positive electrode active material 561 and/or the positive electrode active material 562 may have high resistance because of a composite oxide, and it becomes difficult to collect current from the positive electrode active material 561 and/or the positive electrode active material 562 to the positive electrode current collector 550. In that case, as shown in FIG.
  • the positive electrode has a conductive material 553 and a conductive material 554, and the conductive material 553 and the conductive material 554 function to assist the current path between the positive electrode active material 561 and the positive electrode current collector 550, the current path between the multiple positive electrode active materials 561, the current path between the multiple positive electrode active materials and the positive electrode current collector 550, the current path between the positive electrode active material 562 and the positive electrode current collector 550, the current path between the multiple positive electrode active materials 562, and the like.
  • the conductive material is also called a conductive agent or a conductive assistant due to its role. Note that, since increasing the conductive material reduces the proportion of the positive electrode active material, the conductive material 553 and the conductive material 554 may be either one of them.
  • the conductive material 553 and the conductive material 554 may have a material with lower resistance than the positive electrode active material 561.
  • the conductive material 553 and the conductive material 554 may have a material with lower resistance than the positive electrode active material 562.
  • the conductive material 553 is carbon black (furnace black, acetylene black, graphite, etc.). Most carbon blacks have a smaller particle size than the positive electrode active material 561.
  • the conductive material 554 is carbon nanotubes (CNT) and VGCF (registered trademark). Some conductive materials are in sheet form, and an example of a sheet-like conductive material is multilayer graphene. A sheet-like conductive material may appear thread-like in the cross section of the positive electrode.
  • the conductive material 553 can enter the gaps between the positive electrode active material 561 and the like, and is also prone to agglomeration. Therefore, the conductive material 553 can assist the conductive path between the positive electrode active materials arranged nearby.
  • the conductive material 554 also has a bent region, but is larger than the positive electrode active material 561 and the like. Therefore, the conductive material 554 can assist the conductive path between the positive electrode active materials arranged apart or at a distance, in addition to between adjacent positive electrode active materials. In this way, it is advisable to mix conductive materials of two or more shapes.
  • a sheet-like conductive additive may be used as the conductive material 554.
  • the weight of the carbon black in the mixed slurry state is preferably 1.5 to 20 times, and more preferably 2 to 9.5 times, that of the graphene.
  • the carbon black does not aggregate and is easily dispersed. Furthermore, when the mixing ratio of multi-layer graphene and carbon black is within the above range, the electrode density can be made higher than when only carbon black is used as the conductive material. By increasing the electrode density, the capacity per unit weight can be increased.
  • the electrolyte is an electrolyte (lithium salt) dissolved in an organic solvent, and can also be called an electrolytic solution.
  • the electrolyte is not limited to an electrolyte that contains an organic solvent that is liquid at room temperature, but is a concept that includes a solid electrolyte.
  • the electrolyte is a concept that includes an electrolyte (semi-solid electrolyte) that contains both an organic solvent that is liquid at room temperature and a solid electrolyte that is solid at room temperature.
  • Organic solvents that are liquid at room temperature An example of an organic solvent that is liquid at room temperature will be described below.
  • the organic solvent that is liquid at room temperature is preferably an aprotic organic solvent, and for example, one of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, chloroethylene carbonate, vinylene carbonate, ⁇ -butyrolactone, ⁇ -valerolactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate (EP), propyl propionate (PP), methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl ether, methyl diglyme, acetonitrile, benzonitrile, tetrahydrofuran, sulfolane, sultone, etc., or two or more of
  • the ionic liquid is composed of a cation and an anion, and includes an organic cation and an anion.
  • Examples of the organic cation used in the electrolyte include aliphatic onium cations such as quaternary ammonium cations, tertiary sulfonium cations, and quaternary phosphonium cations, and aromatic cations such as imidazolium cations and pyridinium cations.
  • Examples of the anion used in the electrolyte include monovalent amide anions, monovalent methide anions, fluorosulfonate anions, perfluoroalkylsulfonate anions, tetrafluoroborate anions, perfluoroalkylborate anions, hexafluorophosphate anions, and perfluoroalkylphosphate anions.
  • the lithium salt to be dissolved in the organic solvent may be, for example , one or more selected from LiPF6 , LiClO4 , LiAsF6 , LiBF4 , LiAlCl4 , LiSCN, LiBr , LiI, Li2SO4, Li2B10Cl10, Li2B12Cl12, LiCF3SO3, LiC4F9SO3, LiC(CF3SO2)3 , LiC ( C2F5SO2 ) 3 , LiN ( CF3SO2 ) 2 , LiN ( C4F9SO2 ) ( CF3SO2 ) , and LiN( C2F5SO2 ) 2 .
  • the organic solvent may also have an additive.
  • an additive for example, vinylene carbonate (VC), propane sultone (PS), tert-butylbenzene (TBB), fluoroethylene carbonate (FEC), lithium bis(oxalate)borate (LiBOB), or nitrile compounds such as succinonitrile, adiponitrile (ADN), or ethylene glycol bis(propionitrile)ether (EGBE) may be added to the organic solvent as an additive. It is preferable to add two or more nitrile compounds.
  • fluorobenzene may be added to the organic solvent.
  • the concentration of the additive may be, for example, 0.1 wt% to 5 wt% relative to the entire electrolyte.
  • LiBOB is particularly preferable because it is easy to form a good coating.
  • VC or FEC is preferable because it can form a good coating on the negative electrode during charging and discharging to improve the cycle characteristics.
  • PS or EGBE is preferable because it can form a good coating on the positive electrode during charging and discharging to improve the cycle characteristics.
  • FB is preferable because it improves the wettability of the organic solvent to the positive electrode and the negative electrode.
  • Nitrile compounds are preferred because the nitrile groups are oriented toward the positive and negative electrodes, inhibiting the oxidative decomposition of organic solvents and improving voltage resistance.
  • nitrile compounds are preferred because they can prevent copper from dissolving during overdischarge.
  • the electrolyte does not need to be liquid at room temperature, and a polymer gel electrolyte may be used as an organic solvent. Using a polymer gel electrolyte increases safety against leakage, etc. Also, it is possible to make the battery cell thinner and lighter.
  • Polymers that can be gelled include silicone gel, acrylic gel, acrylonitrile gel, polyethylene oxide gel, polypropylene oxide gel, fluorine-based polymer gel, etc.
  • polymer for example, a polymer having a polyalkylene oxide structure such as polyethylene oxide (PEO), PVDF, polyacrylonitrile, etc., and copolymers containing these can be used.
  • PEO polyethylene oxide
  • PVDF-HFP which is a copolymer of PVDF and hexafluoropropylene (HFP)
  • the polymer formed may have a porous shape.
  • the electrolyte does not need to be liquid at room temperature, and a solid electrolyte may be used.
  • a solid electrolyte may be used.
  • a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a halide-based solid electrolyte may be used.
  • a solid electrolyte having a polymer material such as PEO (polyethylene oxide) may also be used.
  • PEO polyethylene oxide
  • Sulfide -based solid electrolytes include thiolithium-based electrolytes ( Li10GeP2S12 , Li3.25Ge0.25P0.75S4 , etc. ) , sulfide glass ( 70Li2S.30P2S530Li2S.26B2S3.44LiI , 63Li2S.36SiS2.1Li3PO4 , 57Li2S.38SiS2.5Li4SiO4 , 50Li2S.50GeS2 , etc. ) , and sulfide crystallized glass ( Li7P3S11 , Li3.25P0.95S4 , etc. ) .
  • Sulfide-based solid electrolytes have the advantages of being highly conductive, being able to be synthesized at low temperatures, and being relatively soft, which makes it easier to maintain conductive paths even after charging and discharging.
  • oxide-based solid electrolytes examples include materials having a perovskite crystal structure (La2 /3- xLi3xTiO3 , etc.), materials having a NASICON crystal structure (Li1 + xAlxTi2 -x ( PO4 ) 3 , etc.), materials having a garnet crystal structure ( Li7La3Zr2O12 , etc. ), materials having a LISICON crystal structure ( Li14ZnGe4O16 , etc.), LLZO ( Li7La3Zr2O12 ), oxide glass ( Li3PO4 - Li4SiO4 , 50Li4SiO4.50Li3BO3 , etc.
  • oxide crystallized glass Li1.07Al0.69Ti1.46 ( PO4 ) 3 , etc.
  • oxide - based solid electrolytes Li1.5Al0.5Ge1.5 ( PO4 ) 3 , etc.
  • Oxide - based solid electrolytes have the advantage of being stable in the air.
  • Halide-based solid electrolytes include LiAlCl 4 , Li 3 InBr 6 , LiF, LiCl, LiBr, LiI, etc.
  • Composite materials in which these halide-based solid electrolytes are filled into the pores of porous aluminum oxide or porous silica can also be used as solid electrolytes.
  • Li1 + xAlxTi2 -x ( PO4 ) 3 (0 ⁇ x ⁇ 1) (hereinafter referred to as LATP) having a NASICON type crystal structure is preferable because it contains the same elements as the main raw materials or additive elements of the positive electrode active material used in one embodiment of the present invention, that is, aluminum and titanium, and therefore is expected to have a synergistic effect on improving cycle characteristics. In addition, it is expected to improve productivity by reducing the number of steps.
  • the NASICON type crystal structure refers to a compound represented by M2 ( AO4 ) 3 (M: transition metal, A: S, P, As, Mo, W, etc.), which has a structure in which MO6 octahedrons and AO4 tetrahedrons are arranged three-dimensionally with vertices shared.
  • low temperature electrolyte An example of an electrolyte suitable for low temperature use (hereinafter referred to as low temperature electrolyte) will be described below.
  • the above volume ratio may be the volume ratio before mixing with the electrolyte, and the outside air when mixing the electrolyte may be room temperature (typically 25° C.).
  • EC is a cyclic carbonate and has a high relative dielectric constant, which has the effect of promoting the dissociation of lithium salts.
  • EC has a high viscosity and a high freezing point (melting point) of 38°C, so when EC alone is used as an organic solvent, it is difficult to use it in a low-temperature environment. Therefore, the organic solvent specifically described as one aspect of the present invention is not EC alone, but further contains EMC and DMC.
  • EMC is a chain carbonate, has the effect of reducing the viscosity of the electrolyte, and has a freezing point of -54°C.
  • DMC is also a chain carbonate, has the effect of reducing the viscosity of the electrolyte, and has a freezing point of -43°C.
  • the lithium salt dissolved in the organic solvent of the low-temperature electrolyte can be selected from the lithium salts described above.
  • Additives contained in the organic solvent of the low-temperature electrolyte can be selected from the additives mentioned above.
  • the unit cell has a negative electrode.
  • the negative electrode has a negative electrode active material layer and a negative electrode current collector.
  • the negative electrode active material layer has a negative electrode active material, and may further have a conductive assistant and a binder.
  • the negative electrode has a negative electrode current collector.
  • the negative electrode current collector can be made of the same material as the positive electrode current collector.
  • the negative electrode includes a negative electrode active material, which may be, for example, an alloy material or a carbon material.
  • the negative electrode active material can be an element capable of performing a charge/discharge reaction by alloying/dealloying reaction with lithium.
  • a material containing at least one of silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, indium, etc. can be used.
  • Such elements have a larger capacity than carbon, and silicon in particular has a high theoretical capacity of 4200 mAh/g. For this reason, it is preferable to use silicon as the negative electrode active material. Compounds containing these elements may also be used.
  • Examples include SiO, Mg2Si , Mg2Ge , SnO, SnO2 , Mg2Sn , SnS2 , V2Sn3 , FeSn2 , CoSn2 , Ni3Sn2 , Cu6Sn5 , Ag3Sn, Ag3Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7 , CoSb3 , InSb , SbSn , etc.
  • elements capable of carrying out charge/discharge reactions by alloying/dealloying reactions with lithium, and compounds containing such elements may be referred to as alloying materials.
  • SiO refers to, for example, silicon monoxide.
  • SiO can be expressed as SiO x .
  • x preferably has a value of 1 or close to 1.
  • x is preferably 0.2 or more and 1.5 or less, and more preferably 0.3 or more and 1.2 or less.
  • the carbon material may be graphite, easily graphitizable carbon (soft carbon), non-graphitizable carbon (hard carbon), carbon fiber (carbon nanotube), graphene, carbon black, etc.
  • Examples of graphite include artificial graphite and natural graphite.
  • Examples of artificial graphite include mesocarbon microbeads (MCMB), coke-based artificial graphite, and pitch-based artificial graphite.
  • MCMB mesocarbon microbeads
  • pitch-based artificial graphite As the artificial graphite, spherical graphite having a spherical shape can be used.
  • MCMB may have a spherical shape, which is preferable.
  • Examples of natural graphite include flake graphite and spherical natural graphite.
  • graphite When lithium ions are inserted into graphite (when a lithium-graphite intercalation compound is formed), graphite exhibits a low potential (0.05 V to 0.3 V vs. Li/Li + ) similar to that of lithium metal. This allows lithium ion batteries using graphite to exhibit a high operating voltage. Furthermore, graphite is preferable because it has the advantages of a relatively high capacity per unit volume, a relatively small volume expansion, low cost, and higher safety than lithium metal.
  • oxides such as titanium dioxide ( TiO2 ) , lithium titanium oxide ( Li4Ti5O12 ), lithium-graphite intercalation compound ( LixC6 ), niobium pentoxide ( Nb2O5 ), tungsten dioxide ( WO2 ), and molybdenum dioxide ( MoO2 ) can be used as the negative electrode active material.
  • TiO2 titanium dioxide
  • Li4Ti5O12 lithium titanium oxide
  • LixC6 lithium-graphite intercalation compound
  • Nb2O5 niobium pentoxide
  • WO2 tungsten dioxide
  • MoO2 molybdenum dioxide
  • Li2.6Co0.4N is preferable because it shows a large discharge capacity (900mAh/g, 1890mAh/ cm3 per active material weight).
  • the nitride of lithium and a transition metal When a nitride of lithium and a transition metal is used, lithium ions are contained in the negative electrode active material, and therefore it is preferable that the nitride of lithium and a transition metal is combined with a material not containing lithium ions as a positive electrode active material, such as V 2 O 5 or Cr 3 O 8. Even when a material containing lithium ions is used as the positive electrode active material, the nitride of lithium and a transition metal can be used as the negative electrode active material by desorbing the lithium ions contained in the positive electrode active material in advance.
  • materials that undergo conversion reactions can be used as negative electrode active materials.
  • transition metal oxides that do not form an alloy with lithium such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO)
  • Materials that undergo conversion reactions include oxides such as Fe2O3 , CuO, Cu2O , RuO2 , and Cr2O3 , sulfides such as CoS0.89 , NiS , and CuS, nitrides such as Zn3N2 , Cu3N , and Ge3N4 , phosphides such as NiP2 , FeP2 , and CoP3 , and fluorides such as FeF3 and BiF3 .
  • the conductive material and binder that can be used in the negative electrode active material layer can be the same materials as the conductive material and binder that can be used in the positive electrode active material layer.
  • a negative electrode having no negative electrode active material can be used.
  • lithium is deposited on the negative electrode current collector during charging, and the lithium on the negative electrode current collector can be dissolved during discharging. Therefore, except in a fully discharged state, the negative electrode has lithium on the negative electrode current collector.
  • a film for uniformly depositing lithium may be provided on the negative electrode current collector.
  • a solid electrolyte having lithium ion conductivity can be used.
  • a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a polymer-based solid electrolyte, etc. can be used.
  • a polymer-based solid electrolyte is suitable as a film for uniformly depositing lithium, since it is relatively easy to form a uniform film on the negative electrode current collector.
  • a negative electrode current collector with irregularities can be used.
  • the concaves of the negative electrode current collector become cavities into which the lithium contained in the negative electrode current collector is likely to precipitate, so that it is possible to prevent the lithium from forming a dendritic shape when it precipitates.
  • the negative electrode has a conductive material which can be selected from the conductive materials of the positive electrode described above.
  • the conductive material of the negative electrode can be different from the conductive material of the positive electrode.
  • the battery cell has a separator disposed between the positive electrode and the negative electrode.
  • the separator insulates the positive electrode from the negative electrode. It is preferable that the separator is made of a material that is stable against the electrolyte and has excellent liquid retention.
  • the separator may be made of, for example, paper or other cellulose-containing fibers, nonwoven fabrics, glass fibers, ceramics, or synthetic fibers made of nylon (polyamide), vinylon (polyvinyl alcohol-based fibers), polyester, polyimide, acrylic, polyolefin, or polyurethane.
  • the separator preferably has a porosity of 30% to 85%, preferably 45% to 65%.
  • a high porosity is preferable because it is easier for the electrolyte to be impregnated.
  • the porosity of the separator may be different between the positive electrode side and the negative electrode side, and it is preferable that the porosity on the positive electrode side is higher than the porosity on the negative electrode side.
  • the same material may be made to have different porosities, or different materials with different porosities may be used. When different materials are used, the porosity of the separator can be made different by stacking them.
  • the thickness of the separator should be 5 ⁇ m or more and 200 ⁇ m or less, preferably 5 ⁇ m or more and 100 ⁇ m or less.
  • the separator preferably has an average pore size of 40 nm to 3 ⁇ m, more preferably 70 nm to 1 ⁇ m. A larger average pore size is preferable because it facilitates carrier ion generation.
  • the average pore size of the separator may be different between the positive electrode side and the negative electrode side, and it is preferable that the average pore size on the positive electrode side is larger than the average pore size on the negative electrode side. To make the average pore size different, the same material may be used with different average pore sizes, or different materials with different average pore sizes may be used. When different materials are used, the average pore size of the separator can be made different by stacking them.
  • the separator should preferably have a heat resistance of 200°C or higher.
  • a separator made of polyimide that has a thickness of 10 ⁇ m or more and 50 ⁇ m or less and a porosity of 75% or more and 85% or less, as this improves the output characteristics of the battery cell.
  • the separator may be processed into a bag shape and the bag-shaped separator may be arranged to wrap or sandwich either the positive electrode or the negative electrode.
  • the thickness of the entire separator is preferably 1 ⁇ m or more and 100 ⁇ m or less, and within the thickness range, the separator may have either a single-layer structure or a multi-layer structure.
  • an organic material film such as polypropylene or polyethylene coated with a ceramic material, a fluorine material, a polyamide material, or a mixture of these can be used.
  • the ceramic material for example, aluminum oxide particles or silicon oxide particles can be used.
  • fluorine material for example, PVDF or polytetrafluoroethylene can be used.
  • polyamide material for example, nylon or aramid (meta-aramid, para-aramid) can be used.
  • Coating the separator surface with a ceramic material improves oxidation resistance, suppressing the separator's deterioration during high-voltage charging and discharging and improving the reliability of the battery cell.
  • Coating the separator surface with a fluorine-based material also makes it easier for the separator and electrodes to adhere to each other, improving output characteristics.
  • Coating the separator surface with a polyamide-based material, especially aramid improves heat resistance, improving the safety of the battery cell.
  • both sides of a polypropylene film may be coated with a mixture of aluminum oxide and aramid.
  • the surface of the polypropylene film that comes into contact with the positive electrode may be coated with a mixture of aluminum oxide and aramid, and the surface that comes into contact with the negative electrode may be coated with a fluorine-based material.
  • the functions of each material can be imparted to the separator, so even if the separator as a whole is thin, insulation between the positive and negative electrodes can be ensured and the safety of the battery cell can be maintained. This is preferable because it allows the capacity per volume of the battery cell to be increased.
  • the unit cell has an exterior body.
  • a metal material such as aluminum or a resin material can be used as the exterior body.
  • a film-shaped exterior body can be used.
  • a three-layer structure film can be used in which a thin metal film having excellent flexibility such as aluminum, stainless steel, copper, nickel, etc. is provided on a film made of a material such as polyethylene, polypropylene, polycarbonate, ionomer, polyamide, etc., and an insulating synthetic resin film such as a polyamide-based resin or polyester-based resin is further provided on the thin metal film as the outer surface of the exterior body.
  • the configuration of the single cell is illustrated, but the interpretation is not limited to the above example.
  • a transition metal M source 81 (referred to as M source in the drawing) shown in Fig. 14 will be described.
  • M source for example, at least one of nickel, cobalt, and manganese can be used.
  • the transition metal M there is a case where only nickel is used, a case where two types of cobalt and manganese are used, a case where two types of nickel and cobalt are used, or a case where three types of nickel, cobalt, and manganese are used.
  • nickel, cobalt, and manganese When nickel, cobalt, and manganese are used, it is preferable to mix nickel, cobalt, and manganese in a ratio that allows a layered rock salt type crystal structure to be formed.
  • the transition metal M contains a large amount of nickel
  • the raw material may be cheaper than when the transition metal M contains a large amount of cobalt, and the discharge capacity per weight may increase, which is preferable.
  • Such an active material is suitable for electric vehicles.
  • the nickel content of the transition metal M is preferably more than 25 atomic%, more preferably 60 atomic% or more, and even more preferably 80 atomic% or more.
  • the nickel content of the transition metal M is 95 atomic% or less.
  • the transition metal M When cobalt is used as the transition metal M, the average discharge voltage is high, and since cobalt contributes to stabilizing the layered rock-salt structure, it is possible to form a highly reliable battery cell, which is preferable.
  • Such an active material is suitable for electric vehicles.
  • the cobalt content of the transition metal M is 2.5 atomic % or more and 34 atomic % or less. Note that the transition metal M does not necessarily have to contain cobalt.
  • manganese as the transition metal M, as this improves heat resistance and chemical stability.
  • Such active materials are suitable for electric vehicles.
  • manganese among the transition metals M is 2.5 atomic % or more and 34 atomic % or less. Note that the transition metal M does not necessarily have to contain manganese.
  • the transition metal M source 81 is prepared as an aqueous solution containing the transition metal M.
  • a nickel salt for example, nickel sulfate, nickel chloride, nickel nitrate, or a hydrate thereof can be used.
  • An aqueous solution of a nickel alkoxide or an organic nickel complex can also be used.
  • an organic acid salt refers to a compound of an organic acid, such as acetic acid, citric acid, oxalic acid, formic acid, or butyric acid, and a metal.
  • a cobalt salt for example, cobalt sulfate, cobalt chloride, cobalt nitrate, or an aqueous solution of a hydrate thereof can be used.
  • an aqueous solution of an organic acid salt of cobalt such as cobalt acetate, or a hydrate thereof can be used.
  • an aqueous solution of a cobalt alkoxide or an organic cobalt complex can be used.
  • a manganese salt such as manganese sulfate, manganese chloride, manganese nitrate, or an aqueous solution of a hydrate thereof can be used.
  • an aqueous solution of an organic acid salt of manganese such as manganese acetate, or a hydrate thereof can be used.
  • an aqueous solution of a manganese alkoxide or an organic manganese complex can be used.
  • an aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate dissolved in pure water is prepared as the transition metal M source 81.
  • the nickel, cobalt, and manganese are weighed out so that the atomic ratio of Ni:Co:Mn is 8:1:1 or close to this.
  • an additive element source may be added to the transition metal M source 81.
  • the additive element added to the transition metal M source 81 is referred to as a first additive element.
  • the first additive element may be one or more selected from the group consisting of gallium, aluminum, boron, and indium.
  • the first additive element When the first additive element is gallium, it can be referred to as a gallium source.
  • a gallium source a compound containing gallium can be used.
  • the compound containing gallium for example, gallium sulfate, gallium chloride, or gallium nitrate, or a hydrate thereof can be used.
  • a gallium alkoxide or an organic gallium complex can be used.
  • an organic acid of gallium such as gallium acetate, or a hydrate thereof can be used.
  • the first added element is aluminum
  • it can be referred to as an aluminum source.
  • a compound containing aluminum can be used.
  • the compound containing aluminum for example, aluminum sulfate, aluminum chloride, or aluminum nitrate, or a hydrate thereof can be used.
  • an aluminum alkoxide or an organic aluminum complex can be used.
  • an organic acid of aluminum such as aluminum acetate, or a hydrate thereof can be used.
  • the first additive element is boron
  • it can be referred to as a boron source.
  • a compound containing boron can be used.
  • the compound containing boron for example, boric acid or a borate can be used.
  • the first additive element when it can be referred to as an indium source.
  • a compound containing indium can be used.
  • the compound containing indium for example, indium sulfate, indium chloride, or indium nitrate, or a hydrate thereof can be used.
  • an indium alkoxide or an organic indium complex can be used.
  • an organic acid of indium such as indium acetate, or a hydrate thereof can be used.
  • the chelating agent 83 shown in FIG. 14 will be described.
  • materials constituting the chelating agent include glycine, oxine, 1-nitroso-2-naphthol, 2-mercaptobenzothiazole, and EDTA (ethylenediaminetetraacetic acid).
  • glycine, oxine, 1-nitroso-2-naphthol, and 2-mercaptobenzothiazole may be used.
  • an aqueous solution in which these are dissolved in pure water becomes a chelating agent
  • an aqueous solution in which glycine is dissolved may be referred to as a glycine aqueous solution.
  • a chelating agent is a complexing agent that creates a chelate compound, and is preferable to a general complexing agent.
  • a complexing agent may be used instead of a chelating agent, and ammonia water may be used as the complexing agent.
  • a chelating agent is preferable because it makes it easier to control the pH of the reaction tank when obtaining a coprecipitate, for example a cobalt compound.
  • the use of a chelating agent is also preferable because it suppresses the generation of unnecessary crystal nuclei and promotes growth. Suppressing the generation of unnecessary nuclei suppresses the generation of fine particles, making it possible to obtain a complex oxide with a good particle size distribution.
  • the use of a chelating agent also makes it possible to delay the acid-base reaction, and as the reaction progresses gradually, it is possible to obtain secondary particles that are nearly spherical.
  • Glycine has the effect of keeping the pH value constant at or near a pH of 9 or more and 10 or less, and using an aqueous glycine solution as a chelating agent is preferable because it makes it easier to control the pH of the reaction tank when obtaining the cobalt compound.
  • the glycine concentration of the aqueous glycine solution is preferably 0.05 mol/L or more and 0.09 mol/L or less in the acidic solution 91.
  • the aqueous solution used in the present embodiment is preferably pure water.
  • Pure water is water having a resistivity of 1 M ⁇ cm or more, more preferably 10 M ⁇ cm or more, and even more preferably 15 M ⁇ cm or more. Water that satisfies the resistivity range has high purity and contains very few impurities.
  • step S30 a transition metal M source 81 and a chelating agent 83 are mixed to prepare an acidic solution 91.
  • the alkaline solution may be, for example, an aqueous solution containing sodium hydroxide, potassium hydroxide, lithium hydroxide, or ammonia, and is not limited to these aqueous solutions as long as it functions as a pH adjuster.
  • an aqueous solution in which a plurality of types selected from sodium hydroxide, potassium hydroxide, and lithium hydroxide are dissolved in water may be used.
  • the water used may be the above-mentioned pure water.
  • Water or an aqueous solution may be prepared together with the alkaline solution 84.
  • the water or aqueous solution may be referred to as the charging solution or the adjustment solution, and may refer to any aqueous solution in the initial reaction state.
  • the water may be the above-mentioned pure water.
  • a chelating agent containing the above-mentioned pure water may also be used as the aqueous solution. When a chelating agent is used, the effect described above in ⁇ Chelating Agent> is obtained. It is not necessary to prepare water or an aqueous solution.
  • step S31 shown in Fig. 14 will be described.
  • the acidic solution 91 and the alkaline solution 84 are mixed.
  • the acidic solution 91 and the alkaline solution 84 react with each other, and a coprecipitate 95 can be obtained.
  • the above reaction in step 31 may be referred to as a neutralization reaction, an acid-base reaction, or a co-precipitation reaction.
  • the resulting coprecipitate 95 may be referred to as a precursor of the positive electrode active material.
  • the pH of the reaction system is set to 9 or more and 11 or less, preferably 9.8 or more and 10.3 or less.
  • the acidic solution 91 is placed in a reaction vessel or the like (e.g., a beaker) of the reaction tank and the alkaline solution 84 is dropped into the reaction vessel, it is preferable that the pH of the aqueous solution in the reaction vessel satisfies or maintains the above-mentioned range of conditions.
  • the term "maintaining the above-mentioned range of conditions" includes that when the pH value of the aqueous solution in the reaction vessel fluctuates due to the dropping of the alkaline solution 84, the pH of the aqueous solution in the reaction vessel satisfies the above-mentioned range when a certain time has elapsed since the dropping.
  • the certain time is 1 second or more and 5 seconds or less, preferably 1 second or more and 3 seconds or less.
  • the alkaline solution 84 is placed in the reaction vessel and the acidic solution 91 is dropped, it is preferable that the pH of the aqueous solution in the reaction vessel satisfies or maintains the above-mentioned range of conditions.
  • the dropping speed of the acidic solution 91 or the alkaline solution 84 is preferably set to 0.2 mL/min or more and 0.8 mL/min or less in consideration of ease of control of the pH condition.
  • the alkaline solution 84 or the acidic solution 91 may be stirred using a stirring means.
  • the stirring means may be a stirrer, specifically a stirrer with stirring blades.
  • the stirrer may be provided with 2 to 6 stirring blades, and when using 4 stirring blades, for example, they may be arranged in a cross shape when viewed from above.
  • the rotation speed of the stirring means may be 800 rpm to 1200 rpm.
  • the alkaline solution 84 or acidic solution 91 in the reaction vessel is adjusted to a temperature between 50°C and 90°C. Dripping of either the alkaline solution 84 or the acidic solution 91 should begin after the solution has reached that temperature.
  • the inside of the reaction vessel should preferably be in an inert atmosphere.
  • nitrogen gas should be introduced at a flow rate of 0.5 L/min to 2 L/min.
  • a reflux condenser may also be placed in the reaction vessel.
  • the reflux condenser allows nitrogen gas to be released from the reaction vessel. Water produced by reflux cooling can be returned to the reaction vessel.
  • a cobalt compound is precipitated in the reaction vessel as a coprecipitate 95. It is preferable to perform filtration to recover the coprecipitate 95. When filtering, it is preferable to wash the reaction product precipitated in the reaction vessel with pure water, and then add an organic solvent with a low boiling point (e.g., acetone, etc.) before performing the above filtration.
  • an organic solvent with a low boiling point e.g., acetone, etc.
  • coprecipitate 95 it is dried in a vacuum atmosphere at 60°C to 90°C for 0.5 hours to 3 hours. Coprecipitate 95 may be obtained through such a procedure.
  • the cobalt compound of the coprecipitate 95 is preferably cobalt hydroxide (e.g., Co(OH) 2 , etc.).
  • the cobalt hydroxide obtained after filtration is obtained as secondary particles formed by agglomeration of primary particles.
  • Li source in the drawing a lithium compound is prepared as the lithium source 88 (referred to as Li source in the drawing) shown in Fig. 14.
  • the lithium compound lithium hydroxide, lithium carbonate, lithium oxide, or lithium nitrate is prepared.
  • cobalt hydroxide obtained as the coprecipitate 95
  • lithium hydroxide can be used as the lithium compound.
  • the lithium compound should be crushed in advance.
  • the mortar should preferably be made of a material that does not release impurities. Specifically, an alumina mortar with a purity of 90 wt% or more, preferably 99 wt% or more, should be used. Wet crushing using a ball mill may also be used. Acetone can be used as the solvent in wet crushing.
  • Step S41> 14 the coprecipitate 95 and the lithium source 88 are mixed. Then, a mixed mixture 97 is obtained.
  • a revolutionary agitator may be used as a means for mixing the coprecipitate 95 and the lithium source 88. Since the revolutionary agitator does not use media, pulverization is often not performed.
  • a ball mill or a bead mill can be used.
  • Alumina balls or zirconia balls can be used as the media for the ball mill or bead mill.
  • centrifugal force is applied to the media, making it possible to microparticulate the material. If there is a concern about contamination from the media, etc., it is preferable to use the above-mentioned zirconia balls.
  • Dry grinding is performed in an inert gas or air, and can grind to a particle size of 3.5 ⁇ m or less, preferably 3 ⁇ m or less.
  • Wet grinding is performed in a liquid, and can grind to a particle size of nanometers. In other words, wet grinding is recommended if you want to reduce the particle size.
  • Step S44 the mixture is heated.
  • Step S44 may be referred to as a main baking.
  • a composite oxide may be obtained as a positive electrode active material 90.
  • the positive electrode active material 90 may have a shape similar to that of the coprecipitate 95, which is a precursor.
  • the heating temperature is preferably 700° C. or more and less than 1100° C., more preferably 800° C. or more and 1000° C. or less, and even more preferably 800° C. or more and 950° C. or less.
  • heating is performed at a temperature at which at least the coprecipitate 95 and the lithium source 88 diffuse into each other. This temperature is the reason why it is called the main calcination.
  • the heating time can be, for example, from 1 hour to 100 hours, and preferably from 2 hours to 20 hours.
  • the heating atmosphere is preferably an oxygen-containing atmosphere or a so-called dry air atmosphere containing oxygen with little water (e.g., a dew point of -50°C or less, more preferably a dew point of -80°C or less).
  • the temperature increase rate should be 150°C/hour or more and 250°C/hour or less.
  • the flow rate of dry air that can form the drying atmosphere is preferably 3 L/min or more and 10 L/min or less.
  • the temperature decrease time is preferably 10 hours or more and 50 hours or less until the temperature drops from the specified temperature to room temperature, and the temperature decrease rate can be calculated from the temperature decrease time, etc.
  • the crucible, scabbard, setter, or container used during heating is preferably made of a material that does not emit impurities.
  • a crucible made of alumina with a purity of 99.9% is preferably used.
  • a scabbard made of mullite-cordierite (Al 2 O 3 , SiO 2 , MgO) is preferably used.
  • the mortar when recovering the material after heating, it is preferable to move it from the crucible to a mortar and then recover it, as this prevents impurities from being mixed into the material.
  • the mortar it is preferable for the mortar to be made of a material that does not release impurities, and specifically, it is recommended to use a mortar made of alumina or zirconia with a purity of 90 wt% or more, preferably 99 wt% or more.
  • the positive electrode active material 90 can be produced, and according to production method 1, NCM can be obtained as the positive electrode active material 90.
  • NCM is sometimes referred to as a composite oxide.
  • the amount of impurities contained in the positive electrode active material 90 is low, which is preferable.
  • sulfur may be detected in the positive electrode active material 90.
  • the sulfur concentration can be measured by performing elemental analysis of the positive electrode active material 90 using GD-MS, ICP-MS, etc.
  • a lithium compound 803 is prepared in step S30a, and a phosphorus compound 804 is prepared in step S30b.
  • x:y:z the atomic ratio of lithium, transition metal M, and phosphorus in a composite oxide preferably obtained as a positive electrode active material 90 described later.
  • x:y:z the atomic ratio of lithium, transition metal M, and phosphorus in a composite oxide preferably obtained as a positive electrode active material 90 described later.
  • x:y:z the atomic ratio of lithium, transition metal M, and phosphorus in a composite oxide preferably obtained as a positive electrode active material 90 described later.
  • lithium compounds include lithium chloride (LiCl), lithium acetate (CH 3 COOLi), lithium oxalate ((COOLi) 2 ), lithium carbonate (Li 2 CO 3 ), and lithium hydroxide monohydrate (LiOH.H 2 O).
  • phosphorus compounds include phosphoric acids such as orthophosphoric acid (H 3 PO 4 ), and ammonium hydrogen phosphates such as diammonium hydrogen phosphate ((NH 4 ) 2 HPO 4 ) and ammonium dihydrogen phosphate (NH 4 H 2 PO 4 ).
  • phosphoric acids such as orthophosphoric acid (H 3 PO 4 )
  • ammonium hydrogen phosphates such as diammonium hydrogen phosphate ((NH 4 ) 2 HPO 4 ) and ammonium dihydrogen phosphate (NH 4 H 2 PO 4 ).
  • a solvent 805 is prepared. It is preferable to use water as the solvent 805. Alternatively, a mixture of water and another liquid may be used as the solvent 805. For example, water may be mixed with alcohol.
  • the lithium compound 803 and the phosphorus compound 804, or the reaction product of the lithium compound 803 and the phosphorus compound 804, may have different solubilities in water and alcohol. By using alcohol, the particle size of the formed particles may be smaller.
  • the solvent 805 When water is used as the solvent 805, it is desirable that the solvent be pure water with few impurities and preferably with a resistivity of 1 M ⁇ cm or more, more preferably with a resistivity of 10 M ⁇ cm or more, and even more preferably with a resistivity of 15 M ⁇ cm or more.
  • the capacity of the secondary battery can be increased and/or the reliability of the secondary battery can be increased.
  • step S31 of FIG. 15 the lithium compound 803, the phosphorus compound 804, and the solvent 805 are mixed to obtain a mixture 811 in step S32.
  • the mixing in step S31 can be performed in an atmosphere such as air or an inert gas.
  • nitrogen may be used as the inert gas.
  • the lithium compound 803 prepared in step S30a, the phosphorus compound 804 prepared in step S30b, and the solvent 805 prepared in step S30c are mixed in an air atmosphere.
  • the lithium compound 803 prepared in step S30a and the phosphorus compound 804 prepared in step S30b are added to the solvent 805 prepared in step S30c to form the mixture 811 in step S32.
  • the lithium compound 803, the phosphorus compound 804, and the reaction products of the lithium compound and the phosphorus compound may precipitate in the solution, but some of them do not precipitate and dissolve in the solvent, that is, they exist in the solvent as ions.
  • the pH of the mixture 811 is low, the reaction products may be easily dissolved in the solvent, and if the pH is high, the reaction products may be easily precipitated.
  • a compound having phosphorus and lithium such as Li3PO4 , Li2HPO4 , or LiH2PO4 , may be prepared and added to a solvent to form the mixture 811 in step S32.
  • the pH of the mixture 811 is determined by the type and degree of dissociation of the salt contained in the mixture 811. Therefore, the pH of the mixture 811 changes depending on the lithium compound 803 and the phosphorus compound 804 used as raw materials. For example, when lithium chloride is used as the lithium compound 803 and orthophosphoric acid is used as the phosphorus compound 804, the mixture 811 in step S32 becomes a strong acid. Also, for example, when lithium hydroxide monohydrate is used as the lithium compound 803, the mixture 811 in step S32 tends to become alkaline.
  • step S33 of FIG. 15 a solution P812 is prepared.
  • step S35 the mixture 811 of step S32 and the solution P812 prepared in step S33 are mixed to form a mixture 821 of step S41.
  • the pH of the mixture 821 of step S41 obtained and the mixture 831 of step S82 obtained later can be adjusted.
  • the solution P812 may be dropped while measuring the pH of the mixture 811 of step S32.
  • an alkaline solution or an acidic solution is used depending on the pH of the mixture 811 of step S32.
  • a weak alkaline or weak acidic solution it may be easier to adjust the pH.
  • the pH of the alkaline solution may be 8 or more and 12 or less.
  • the pH of the acidic solution may be 2 or more and 6 or less.
  • ammonia water may be used as the alkaline solution. It is preferable to determine the pH and mixing amount of solution P812 so that the mixture 831 in step S82 described below is acidic or neutral.
  • a transition metal M source 822 is prepared.
  • the transition metal M source 822 one or more of an iron (II) compound, a manganese (II) compound, a cobalt (II) compound, and a nickel (II) compound (hereinafter referred to as an M (II) compound) can be used.
  • the transition metal M source used in the synthesis It is preferable to use a high-purity material as the transition metal M source used in the synthesis.
  • the purity of the material is 3N (99.9%) or more, preferably 4N (99.99%) or more, more preferably 4N5 (99.995%) or more, and even more preferably 5N (99.999%) or more.
  • the transition metal M source has high crystallinity.
  • the transition metal source has single crystal grains.
  • the crystallinity of the transition metal source can be evaluated, for example, from a TEM (transmission electron microscope) image, a STEM (scanning transmission electron microscope) image, a HAADF-STEM (high-angle scattering annular dark-field scanning transmission electron microscope) image, an ABF-STEM (annular bright-field scanning transmission electron microscope) image, etc.
  • X-ray diffraction (XRD), electron beam diffraction, neutron beam diffraction, etc. can also be used to evaluate the crystallinity of the transition metal source. Note that the above crystallinity evaluation can be applied not only to the transition metal source, but also to the evaluation of the crystallinity of primary particles or secondary particles.
  • iron (II) compounds include iron chloride tetrahydrate (FeCl 2 .4H 2 O), iron sulfate heptahydrate (FeSO 4 .7H 2 O), and iron acetate (Fe(CH 3 COO) 2 ).
  • manganese (II) compounds include manganese chloride tetrahydrate ( MnCl2.4H2O ) , manganese sulfate monohydrate ( MnSO4.H2O ), manganese acetate tetrahydrate (Mn( CH3COO ) 2.4H2O ) , and the like.
  • cobalt (II) compounds include cobalt chloride hexahydrate ( CoCl2.6H2O ) , cobalt sulfate heptahydrate ( CoSO4.7H2O ), and cobalt acetate tetrahydrate ( Co ( CH3COO ) 2.4H2O ).
  • nickel (II) compounds include nickel chloride hexahydrate ( NiCl2.6H2O ), nickel sulfate hexahydrate ( NiSO4.6H2O ), nickel acetate tetrahydrate (Ni( CH3COO ) 2.4H2O ) , and the like.
  • the above compound may be prepared as an aqueous solution as the transition metal M source 822.
  • the water used be pure water with few impurities, preferably with a resistivity of 1 M ⁇ cm or more, more preferably with a resistivity of 10 M ⁇ cm or more, and even more preferably with a resistivity of 15 M ⁇ cm or more.
  • step S41 of FIG. 15 the mixture 821 of step S41 is mixed with the transition metal M source 822 to obtain the mixture 831 of step S92.
  • step S41 a solvent can be added to reduce the concentration of mixture 831 in step S92.
  • mixture 821 in step S41, transition metal M source 822, and a solvent can be mixed to produce mixture 831 in step S92.
  • step S93 of FIG. 15 the mixture 831 from step S92 is placed in a heat-resistant and pressure-resistant container such as an autoclave, and then heated at a temperature of 100° C. or more and 350° C. or less, more preferably more than 100° C. and less than 200° C., and at a pressure of 0.11 MPa or more and 100 MPa or less, more preferably 0.11 MPa or more and 2 MPa or less, for 0.5 hours or more and 24 hours or less, more preferably 1 hour or more and 10 hours or less, and even more preferably 1 hour or more and less than 5 hours, and then cooled.
  • step S94 the solution in the heat-resistant and pressure-resistant container is filtered and washed with water.
  • step S95 the mixture is dried and then recovered to obtain the positive electrode active material 90 in step S96.
  • the positive electrode active material 90 can be described as a composite oxide.
  • the obtained positive electrode active material 90 can be expressed as LiMPO 4 (M is one or more of Fe(II), Ni(II), Co(II), and Mn(II)), and specific positive electrode active materials 90 include LiFePO 4 (LFP), LiNiPO 4 , LiCoPO 4 , LiMnPO 4 , LiFe a Ni b PO 4 , LiFe a Co b PO 4 , LiFe a Mn b PO 4 , LiNi a Co b PO 4 , LiNi a Mn b PO 4 (a+b is 1 or less, 0 ⁇ a ⁇ 1, 0 ⁇ b ⁇ 1), LiFe c Ni d Co e PO 4 , LiFe c Ni d Mn Examples include LiFe f Nig Co h Mn i PO 4 (c+d+e is 1 or less, 0 ⁇ c ⁇ 1, 0 ⁇ d ⁇ 1, 0 ⁇ e ⁇ 1), LiFe f Nig Co h Mn i PO 4 (
  • the composite oxide obtained in this embodiment has high crystallinity and is therefore preferable.
  • a composite oxide with high crystallinity can suppress cycle deterioration and the like.
  • the composite oxide may also form single crystal grains.
  • the crystal structure can be identified by performing crystal analysis such as XRD or electron beam diffraction on the positive electrode active material 90.
  • crystal analysis such as XRD or electron beam diffraction
  • LiMPO4 having an olivine type crystal structure is identified as belonging to the space group Pnma.
  • the solution 806 containing lithium can be prepared by dissolving a lithium compound in a solvent.
  • a lithium compound any one or more of lithium hydroxide monohydrate (LiOH.H 2 O), lithium chloride (LiCl), lithium carbonate (Li 2 CO 3 ), lithium acetate (CH 3 COOLi), and lithium oxalate ((COOLi) 2 ) can be used.
  • Water is an example of a solvent for dissolving the lithium compound.
  • water is desirable that the water is pure water with a low impurity content and preferably has a resistivity of 1 M ⁇ cm or more, more preferably a resistivity of 10 M ⁇ cm or more, and even more preferably a resistivity of 15 M ⁇ cm or more.
  • the capacity of the secondary battery can be increased and/or the reliability of the secondary battery can be increased.
  • the solution 807 containing phosphorus can be prepared by dissolving a phosphorus compound in a solvent.
  • a phosphorus compound one or more of phosphoric acid such as orthophosphoric acid (H 3 PO 4 ) or ammonium hydrogen phosphate such as diammonium hydrogen phosphate ((NH 4 ) 2 HPO 4 ) or ammonium dihydrogen phosphate (NH 4 H 2 PO 4 ) can be used.
  • Water is an example of a solvent for dissolving the phosphorus compound.
  • the water be pure water with few impurities, preferably with a resistivity of 1 M ⁇ cm or more, more preferably with a resistivity of 10 M ⁇ cm or more, and even more preferably with a resistivity of 15 M ⁇ cm or more.
  • the capacity of the battery cell can be increased, or the reliability of the battery cell can be increased.
  • step S31 of FIG. 16 a solution 806 containing lithium and a solution 807 containing phosphorus are mixed to obtain a mixture 811 in step S32.
  • the mixing in step S31 can be performed in an atmosphere such as air or an inert gas.
  • nitrogen can be used as the inert gas.
  • the solution 806 containing lithium prepared in step S30a and the solution 807 containing phosphorus prepared in step S30b are mixed in an air atmosphere.
  • a compound containing phosphorus and lithium such as Li3PO4 , Li2HPO4 , or LiH2PO4 , may be prepared and added to a solvent to form the mixture 811 in step S32.
  • step S33 of FIG. 16 a solution 813 containing a transition metal M is prepared.
  • the solution 813 containing the transition metal M can be prepared by dissolving the transition metal M compound in a solvent.
  • the transition metal M compound one or more of an iron (II) compound, a manganese (II) compound, a cobalt (II) compound, and a nickel (II) compound (hereinafter referred to as an M (II) compound) can be used.
  • An example of a solvent for dissolving the transition metal M compound is water. When using water as the solvent, it is desirable to use pure water with few impurities, preferably with a resistivity of 1 M ⁇ cm or more, more preferably with a resistivity of 10 M ⁇ cm or more, and even more preferably with a resistivity of 15 M ⁇ cm or more. By using a high-purity material, it is possible to increase the capacity of the battery cell or increase the reliability of the battery cell.
  • the transition metal M compound used in the synthesis It is preferable to use a high-purity material as the transition metal M compound used in the synthesis.
  • the purity of the material is 3N (99.9%) or more, preferably 4N (99.99%) or more, more preferably 4N5 (99.995%) or more, and even more preferably 5N (99.999%) or more.
  • the transition metal M compound has high crystallinity.
  • the transition metal compound has single crystal grains.
  • the crystallinity of the transition metal compound can be evaluated, for example, from a TEM image, a STEM image, a HAADF-STEM image, an ABF-STEM image, etc.
  • the crystallinity of the transition metal M compound can also be evaluated using X-ray diffraction (XRD), electron beam diffraction, neutron beam diffraction, etc. Note that the above crystallinity evaluation can be applied not only to the transition metal M compound, but also to the evaluation of the crystallinity of primary particles or secondary particles.
  • iron (II) compounds As representative examples of iron (II) compounds, manganese (II) compounds, cobalt (II) compounds, or nickel (II) compounds, the representative examples of iron (II) compounds, manganese (II) compounds, cobalt (II) compounds, or nickel (II) compounds described in this embodiment can be used.
  • step 35 of FIG. 16 the mixture 811 of step S32 is mixed with a solution 813 containing a transition metal M to obtain a mixture 823 of step S41.
  • x:y:z the atomic ratio of lithium, transition metal M, and phosphorus in a composite oxide preferably obtained as a positive electrode active material 90 described later.
  • x:y:z the atomic ratio of lithium, transition metal M, and phosphorus in a composite oxide preferably obtained as a positive electrode active material 90 described later.
  • x:y:z the atomic ratio of lithium, transition metal M, and phosphorus in a composite oxide preferably obtained as a positive electrode active material 90 described later.
  • a solution 813 containing the transition metal M can be dropped little by little into the mixture 811 of step S32 placed in a container to produce a mixture 823 of step S41.
  • mixing it is preferable to stir the solution in the container and the solution used for mixing, and it is also preferable to remove dissolved oxygen by N2 bubbling.
  • the mixture 811 of step S32 can be added dropwise in small amounts to a solution 813 containing the transition metal M placed in a container to produce a mixture 823 of step S41.
  • a solvent can be added to adjust the concentration of the mixture 823 of step S41.
  • the mixture 811 of step S32, the solution 813 containing the transition metal M, and a solvent can be mixed to produce the mixture 823 of step S41.
  • water it is desirable that it be pure water with few impurities, preferably with a resistivity of 1 M ⁇ cm or more, more preferably with a resistivity of 10 M ⁇ cm or more, and even more preferably with a resistivity of 15 M ⁇ cm or more.
  • step S93 of FIG. 16 the mixture 823 from step S41 is placed in a heat-resistant and pressure-resistant container such as an autoclave, and then heated at a temperature of 100° C. or more and 350° C. or less, more preferably more than 100° C. and less than 200° C., and at a pressure of 0.11 MPa or more and 100 MPa or less, more preferably 0.11 MPa or more and 2 MPa or less, for 0.5 hours or more and 24 hours or less, more preferably 1 hour or more and 10 hours or less, and even more preferably 1 hour or more and less than 5 hours, and then cooled.
  • step S94 the solution in the heat-resistant and pressure-resistant container is filtered and washed with water.
  • step S95 the mixture is dried and then recovered to obtain the positive electrode active material 90 in step S96.
  • the positive electrode active material 90 can be described as a composite oxide.
  • the obtained positive electrode active material 90 can be expressed as LiMPO 4 (M is one or more of Fe(II), Ni(II), Co(II), and Mn(II)), and specific positive electrode active materials 90 include LiFePO 4 (LFP), LiNiPO 4 , LiCoPO 4 , LiMnPO 4 , LiFe a Ni b PO 4 , LiFe a Co b PO 4 , LiFe a Mn b PO 4 , LiNi a Co b PO 4 , LiNi a Mn b PO 4 (a+b is 1 or less, 0 ⁇ a ⁇ 1, 0 ⁇ b ⁇ 1), LiFe c Ni d Co e PO 4 , LiFe c Ni d Mn
  • active materials include LiFe f Nig Co h Mn i PO 4 ( c+d+e is 1 or less, 0 ⁇ c ⁇ 1, 0 ⁇ d ⁇ 1, 0 ⁇ e ⁇ 1), LiFe f Nig Co h Mn
  • the composite oxide obtained in this embodiment has high crystallinity and is therefore preferable.
  • a composite oxide with high crystallinity can suppress cycle deterioration and the like.
  • the composite oxide may also form single crystal grains.
  • the crystal structure can be identified by performing crystal analysis such as XRD or electron beam diffraction on the positive electrode active material 90.
  • crystal analysis such as XRD or electron beam diffraction
  • LiMPO4 having an olivine type crystal structure is identified as belonging to the space group Pnma.
  • Method 4 for preparing a positive electrode active material through initial heating will be described with reference to FIGS. 17A to 17C.
  • FIG. 17A to 17C Method 4 for preparing a positive electrode active material through initial heating will be described with reference to FIGS. 17A to 17C.
  • Step S11 In step S11 shown in FIG. 17A, a lithium source (Li source) and a cobalt source (Co source) are prepared as starting materials, that is, lithium and transition metal materials, respectively.
  • Li source Li source
  • Co source cobalt source
  • the lithium source it is preferable to use a compound containing lithium, such as lithium carbonate, lithium hydroxide, lithium nitrate, or lithium fluoride. It is preferable that the lithium source has high purity, for example, a material with a purity of 99.99% or more.
  • cobalt source it is preferable to use a compound containing cobalt, such as cobalt oxide or cobalt hydroxide.
  • the cobalt source is preferably of high purity, for example, a material with a purity of 3N (99.9%) or more, preferably 4N (99.99%) or more, more preferably 4N5 (99.995%) or more, and even more preferably 5N (99.999%) or more may be used.
  • a high purity material impurities in the positive electrode active material can be controlled. As a result, the capacity of the secondary battery is increased and/or the reliability of the secondary battery is improved.
  • the cobalt source has high crystallinity, for example, single crystal grains.
  • the crystallinity of the cobalt source can be evaluated using TEM images, STEM images, HAADF-STEM images, ABF-STEM images, etc., or evaluation using XRD, electron beam diffraction, neutron beam diffraction, etc. Note that the above-mentioned methods for evaluating crystallinity can be applied not only to the evaluation of cobalt sources, but also to the evaluation of other crystallinity.
  • step S12 the lithium source and the cobalt source are pulverized and mixed to prepare a mixed material.
  • the pulverization and mixing can be performed in a dry or wet manner.
  • the wet method is preferable because it can be crushed into smaller pieces.
  • a solvent is prepared.
  • ketones such as acetone, alcohols such as ethanol and isopropanol, ether, dioxane, acetonitrile, N-methyl-2-pyrrolidone (NMP), etc. can be used. It is more preferable to use an aprotic solvent that is less likely to react with lithium.
  • dehydrated acetone with a purity of 99.5% or more is used. It is preferable to mix the lithium source and the cobalt source with dehydrated acetone with a purity of 99.5% or more, in which the moisture content is suppressed to 10 ppm or less, and then pulverize and mix them.
  • dehydrated acetone with the above-mentioned purity it is possible to reduce impurities that may be mixed in.
  • a ball mill, a bead mill, or the like can be used as a means for grinding and mixing.
  • a ball mill it is preferable to use aluminum oxide balls or zirconium oxide balls as the media. Zirconium oxide balls are preferable because they emit less impurities.
  • the peripheral speed it is preferable to set the peripheral speed to 100 mm/s or more and 2000 mm/s or less in order to suppress contamination from the media. In this embodiment, the peripheral speed is set to 838 mm/s (rotation speed 400 rpm, ball mill diameter 40 mm).
  • step S13 shown in FIG. 17A the mixed material is heated.
  • the heating is preferably performed at 800° C. or more and 1100° C. or less, more preferably at 900° C. or more and 1000° C. or less, and even more preferably at about 950° C. If the temperature is too low, the decomposition and melting of the lithium source and the cobalt source may be insufficient. On the other hand, if the temperature is too high, defects may occur due to lithium transpiration from the lithium source and/or cobalt being excessively reduced. For example, cobalt may change from trivalent to divalent, inducing oxygen defects, etc.
  • the heating time should be between 1 hour and 100 hours, and more preferably between 2 hours and 20 hours.
  • the rate of temperature rise depends on the heating temperature reached, but should be between 80°C/hour and 250°C/hour. For example, if heating at 1000°C for 10 hours, the rate of temperature rise should be 200°C/hour.
  • the heating is preferably performed in an atmosphere with little water, such as dry air, for example, an atmosphere with a dew point of ⁇ 50° C. or less, more preferably an atmosphere with a dew point of ⁇ 80° C. or less.
  • the heating is performed in an atmosphere with a dew point of ⁇ 93° C.
  • the impurity concentrations of CH 4 , CO, CO 2 , H 2 , and the like in the heating atmosphere should each be 5 ppb (parts per billion) or less.
  • the heating atmosphere is preferably an atmosphere containing oxygen.
  • the heating atmosphere is preferably an atmosphere containing oxygen.
  • the flow rate of the dry air is preferably 10 L/min.
  • the method of continuously introducing oxygen into the reaction chamber and having oxygen flow through the reaction chamber is called flow.
  • the reaction chamber may be depressurized and then filled with oxygen (or purged) to prevent the oxygen from entering or leaving the reaction chamber.
  • the reaction chamber may be depressurized until the differential pressure system reaches -970 hPa, and then filled with oxygen to 50 hPa.
  • the material can be allowed to cool naturally, but it is preferable that the time required for the temperature to drop from the specified temperature to room temperature is within 10 to 50 hours, for example, 80°C/hour to 250°C/hour, and more preferably 180°C/hour to 210°C/hour.
  • cooling to room temperature is not necessarily required, as long as the material is cooled to a temperature acceptable for the next step.
  • the heating in this process may be performed using a rotary kiln or a roller hearth kiln. Heating using a rotary kiln can be performed while stirring, whether it is a continuous or batch type.
  • the crucible used for heating is preferably an aluminum oxide crucible.
  • An aluminum oxide crucible is a material that does not easily release impurities. In this embodiment, an aluminum oxide crucible with a purity of 99.9% is used. It is preferable to place a lid on the crucible when heating. This can prevent the material from volatilizing or sublimating. Placing a lid on the crucible means that it is possible to prevent the material from volatilizing or sublimating from the time the temperature is increased to the time the temperature is decreased in this step, and it is not necessary to seal the crucible with a lid. For example, as described above, by filling the reaction chamber with oxygen, it is possible to carry out this step without sealing the crucible.
  • a used crucible refers to one that has undergone the process of putting lithium, transition metal M, and/or materials containing additive elements into it and heating it two or less times.
  • a used crucible refers to one that has undergone the process of putting lithium, transition metal M, and/or materials containing additive elements into it and heating it three or more times. This is because when a new crucible is used, there is a risk that some of the materials, including lithium fluoride, may be absorbed, diffused, moved, and/or attached to the sheath during heating.
  • the material After heating, the material may be crushed and sieved as necessary. When recovering the heated material, it may be transferred from the crucible to a mortar and then recovered.
  • the mortar is preferably made of aluminum oxide or zirconium oxide.
  • Aluminum oxide mortars are made of a material that does not easily release impurities. Specifically, an aluminum oxide mortar with a purity of 90% or more, preferably 99% or more, is used. Note that the same heating conditions as those in step S13 can be applied to the heating steps described below other than step S13.
  • lithium cobalt oxide (LiCoO 2 ) can be synthesized as shown in step S14 of Fig. 17A.
  • the median diameter (D50) is used as the particle diameter of lithium cobalt oxide, it is preferable to pulverize the lithium cobalt oxide in order to obtain a positive electrode active material 100 having a relatively small median diameter (D50).
  • the composite oxide is produced by a solid phase method, but the composite oxide may also be produced by a coprecipitation method.
  • the composite oxide may also be produced by a hydrothermal method.
  • step S15 shown in FIG. 17A the lithium cobalt oxide is heated. Since this is the first heating of the lithium cobalt oxide, the heating in step S15 may be called initial heating. Or, since the heating is performed before step S20 described below, it may be called preheating or pretreatment.
  • the crucible and/or lid used in this step are the same as those used in step S13. Although the following effects are expected from the initial heating, the initial heating is not essential to obtain the positive electrode active material which is one aspect of the present invention.
  • initial heating causes lithium to be released from part of the surface layer of the lithium cobalt oxide. It is also expected to have the effect of increasing the internal crystallinity. Furthermore, impurities may be mixed into the lithium source and/or cobalt source prepared in step S11, etc. Initial heating makes it possible to reduce the impurities in the lithium cobalt oxide completed in step S14.
  • the initial heating has the effect of smoothing the surface of the lithium cobalt oxide.
  • a smooth surface means that there are few irregularities, the composite oxide is generally rounded, and the corners are also rounded. Furthermore, a surface is called smooth when there is little foreign matter adhering to it. Foreign matter is thought to be a cause of unevenness, so it is preferable that it does not adhere to the surface.
  • the heating conditions can be selected from those described in step S13.
  • the heating temperature of this step should be lower than the temperature of step S13 in order to maintain the crystal structure of the complex oxide.
  • the heating time of this step should be shorter than the time of step S13 in order to maintain the crystal structure of the complex oxide. For example, heating should be performed at a temperature of 700°C to 1000°C for 2 hours to 20 hours.
  • the effect of increasing the internal crystallinity is, for example, the effect of mitigating distortion, misalignment, etc. resulting from differences in shrinkage, etc., of the lithium cobalt oxide produced in step S13.
  • the heating in step S13 may cause a temperature difference between the surface and the inside of the lithium cobalt oxide.
  • the temperature difference may induce a shrinkage difference. It is also believed that the temperature difference causes the difference in fluidity between the surface and the inside, which leads to the shrinkage difference.
  • the energy related to the shrinkage difference gives the lithium cobalt oxide a difference in internal stress.
  • the internal stress difference is also called strain, and this energy is sometimes called strain energy.
  • the internal stress is removed by the initial heating in step S15, or in other words, the strain energy is thought to be homogenized by the initial heating in step S15.
  • the strain energy is homogenized, the strain of the lithium cobalt oxide is alleviated. As a result, the surface of the lithium cobalt oxide may become smooth. This is also called the surface being improved. In other words, it is believed that the shrinkage difference caused in the lithium cobalt oxide is alleviated and the surface of the composite oxide becomes smooth after step S15.
  • the shrinkage difference may cause microscopic misalignment, such as crystal misalignment, in the lithium cobalt oxide.
  • microscopic misalignment such as crystal misalignment
  • the misalignment it is possible to equalize the misalignment in the composite oxide.
  • the surface of the composite oxide may become smooth. This is also referred to as the alignment of crystal grains.
  • step S15 it is believed that through step S15, the misalignment of crystals and the like that has occurred in the composite oxide is alleviated, and the surface of the composite oxide becomes smooth.
  • lithium cobalt oxide which has a smooth surface, it reduces deterioration during charging and discharging as a secondary battery and prevents cracking of the positive electrode active material.
  • step S14 lithium cobalt oxide that has been synthesized in advance may be used. In this case, steps S11 to S13 can be omitted. By carrying out step S15 on lithium cobalt oxide that has been synthesized in advance, lithium cobalt oxide with a smooth surface can be obtained.
  • step S20 an additive element A to be added to the lithium cobalt oxide that has been initially heated is prepared.
  • the additive element A can be added evenly. Therefore, it is preferable to add the additive element A after the initial heating.
  • the step of preparing the additive element A will be described with reference to FIG. 17B and FIG. 17C.
  • a source of an additive element A (A source) to be added to lithium cobalt oxide is prepared.
  • a lithium source may be prepared together with the additive element A source.
  • the additive element A can be any of the additive elements described in the previous embodiment, such as additive element X and additive element Y. Specifically, one or more elements selected from magnesium, fluorine, nickel, aluminum, titanium, zirconium, vanadium, iron, manganese, chromium, niobium, arsenic, zinc, silicon, sulfur, phosphorus, and boron can be used. Also, one or two elements selected from bromine and beryllium can be used.
  • the source of the additive element can be called a magnesium source.
  • the magnesium source can be magnesium fluoride, magnesium oxide, magnesium hydroxide, magnesium carbonate, or the like.
  • multiple magnesium sources described above may be used.
  • the dopant element source can be referred to as a fluorine source.
  • the fluorine source that can be used include lithium fluoride (LiF), magnesium fluoride ( MgF2 ), aluminum fluoride ( AlF3 ), titanium fluoride ( TiF4 ), cobalt fluoride ( CoF2 , CoF3 ), nickel fluoride ( NiF2 ), zirconium fluoride ( ZrF4 ), vanadium fluoride ( VF5 ), manganese fluoride, iron fluoride, chromium fluoride, niobium fluoride, zinc fluoride ( ZnF2 ), calcium fluoride ( CaF2 ), sodium fluoride (NaF), potassium fluoride (KF), barium fluoride ( BaF2 ), cerium fluoride ( CeF3 , CeF4 ), lanthanum fluoride ( LaF3 ), and sodium aluminum hexafluoride (LiF), magnesium fluoride ( MgF
  • Magnesium fluoride can be used as both a fluorine source and a magnesium source.
  • Lithium fluoride can be used as both a fluorine source and a lithium source.
  • Another lithium source that can be used in step S21 is lithium carbonate.
  • the fluorine source may be a gas, such as fluorine ( F2 ), carbon fluoride, sulfur fluoride, or oxygen fluoride ( OF2 , O2F2 , O3F2 , O4F2 , O5F2 , O6F2 , O2F ) , which may be mixed into the atmosphere in the heating step described below.
  • F2 fluorine
  • OF2 , O2F2 , O3F2 , O4F2 , O5F2 , O6F2 , O2F oxygen fluoride
  • lithium fluoride (LiF) is prepared as the fluorine source
  • magnesium fluoride (MgF 2 ) is prepared as the fluorine source and magnesium source.
  • the amount of lithium fluoride increases, there is a concern that the lithium becomes excessive and the cycle characteristics deteriorate.
  • “near” refers to a value that is greater than 0.9 times and less than 1.1 times the value.
  • Step S22> 17B the magnesium source and the fluorine source are pulverized and mixed. This step can be performed under the pulverization and mixing conditions selected from those described in step S12.
  • Step S23> 17B the material crushed and mixed as described above is collected to obtain a source of additive element A (source A).
  • source A a source of additive element A
  • the source of additive element A shown in step S23 has a plurality of starting materials and can be called a mixture.
  • the particle size of the mixture is preferably a median diameter (D50) of 600 nm or more and 10 ⁇ m or less, more preferably 1 ⁇ m or more and 5 ⁇ m or less. Even when a single material is used as the source of the additive element, the median diameter (D50) is preferably 600 nm or more and 10 ⁇ m or less, more preferably 1 ⁇ m or more and 5 ⁇ m or less.
  • Such a finely powdered mixture makes it easier to uniformly attach the mixture to the surface of the lithium cobalt oxide particles when it is mixed with lithium cobalt oxide in a later process. If the mixture is uniformly attached to the surface of the lithium cobalt oxide particles, it is preferable because it makes it easier to uniformly distribute or diffuse the additive element in the surface layer of the composite oxide after heating.
  • Step S21 A process different from that shown in FIG. 17B will be described with reference to FIG. 17C.
  • step S21 shown in FIG. 17C four types of additive element sources to be added to lithium cobalt oxide are prepared. That is, the types of additive element sources shown in FIG. 17C are different from those shown in FIG. 17B.
  • a lithium source may be prepared together with the additive element sources.
  • a magnesium source Mg source
  • a fluorine source F source
  • a nickel source Ni source
  • an aluminum source Al source
  • the magnesium source and the fluorine source can be selected from the compounds described in FIG. 17B.
  • Nickel oxide, nickel hydroxide, etc. can be used as the nickel source.
  • Aluminum oxide, aluminum hydroxide, etc. can be used as the aluminum source.
  • Steps S22 and S23 shown in FIG. 17C are similar to the steps described in FIG. 17B.
  • lithium cobalt oxide is mixed with a source of additive element A.
  • the mixing conditions in step S101 are preferably milder than those in step S12 in order not to destroy the shape of the lithium cobalt oxide particles.
  • the mixing conditions are preferably lower in rotation speed or shorter in time than those in step S12.
  • the dry method has milder conditions than the wet method.
  • a ball mill, a bead mill, etc. can be used for mixing. When using a ball mill, it is preferable to use zirconium oxide balls as the media.
  • the mixture is mixed dry in a ball mill using zirconium oxide balls with a diameter of 1 mm at 150 rpm for 1 hour.
  • the mixture is performed in a dry room with a dew point of -100°C or higher and -10°C or lower.
  • Step S102> 17A the mixed material is collected to obtain a mixture 903.
  • the material may be crushed and then sieved, if necessary.
  • Figures 17A to 17C illustrate a fabrication method in which an additive element is added after initial heating
  • the additive element may be added at a different timing, or may be added multiple times. The timing may be changed depending on the additive element.
  • the additive elements may be added to the lithium source and the cobalt source in step S11, i.e., at the stage of the starting material for the composite oxide.
  • Figure 18A shows a flow of adding a magnesium source to a lithium source and a cobalt source.
  • Figure 18B shows a flow of adding a magnesium source and an aluminum source to a lithium source and a cobalt source.
  • Figure 18C shows a flow of adding a magnesium source and a nickel source to a lithium source and a cobalt source.
  • the additive element sources shown in Figures 18A to 18C are examples.
  • step S12 the process proceeds to step S12, and then to step S13, and in step S14, lithium cobalt oxide having the additive element can be obtained. It is also possible to control the distribution of the additive element according to the timing of adding the additive element.
  • the additive element added as shown in Figures 18A to 18C is expected to be located inside the positive electrode active material 100.
  • the above-mentioned steps S11 to S14 do not need to be separated from the steps S21 to S23, so it can be said to be a simple and highly productive method.
  • a new additive element may be added in step S20.
  • lithium cobalt oxide that already contains some of the added elements may be used.
  • steps S11 to S14 and some of the steps in step S20 can be omitted. This is a simple and highly productive method.
  • a magnesium source and a fluorine source or a magnesium source, a fluorine source, a nickel source, and an aluminum source may be added as in step S20.
  • step S103 shown in Fig. 17A the mixture 903 is heated.
  • the heating can be performed under a heating condition selected from those described in step S13.
  • the heating time is preferably 2 hours or more.
  • the pressure inside the furnace may be higher than atmospheric pressure in order to increase the oxygen partial pressure of the heating atmosphere. This is because if the oxygen partial pressure of the heating atmosphere is insufficient, cobalt, etc. will be reduced, and lithium cobalt oxide, etc. may not be able to maintain the layered rock salt type crystal structure.
  • the lower limit of the heating temperature in step S103 must be equal to or higher than the temperature at which the reaction between the lithium cobalt oxide and the additive element source proceeds.
  • the temperature at which the reaction proceeds may be any temperature at which mutual diffusion between the lithium cobalt oxide and the elements contained in the additive element source occurs, and may be lower than the melting temperature of these materials.
  • An oxide is used as an example for explanation, and it is known that solid-phase diffusion occurs at a temperature 0.757 times the melting temperature Tm (Tammann temperature Td ). Therefore, the heating temperature in step S103 may be 650°C or higher.
  • the reaction proceeds more easily if the temperature is equal to or higher than the melting temperature of one or more of the materials contained in the mixture 903.
  • the eutectic point of LiF and MgF2 is around 742°C, so that the lower limit of the heating temperature in step S103 is preferably 742°C or higher.
  • the lower limit of the heating temperature is more preferably 830° C. or higher.
  • the upper limit of the heating temperature is below the melting point of lithium cobalt oxide (1130°C). At temperatures close to the melting point, there is a concern that lithium cobalt oxide may decompose, albeit only slightly. Therefore, the upper limit of the heating temperature is preferably 1000°C or lower, more preferably 950°C or lower, and even more preferably 900°C or lower.
  • the heating temperature in step S103 is preferably 650°C to 1130°C, more preferably 650°C to 1000°C, even more preferably 650°C to 950°C, and even more preferably 650°C to 900°C.
  • 742°C to 1130°C is preferred, more preferably 742°C to 1000°C, even more preferably 742°C to 950°C, and even more preferably 742°C to 900°C.
  • 830°C to 1130°C is preferred, more preferably 830°C to 1000°C, even more preferably 830°C to 950°C, and even more preferably 830°C to 900°C.
  • the heating temperature in step S103 is preferably lower than the heating temperature in step S13.
  • the cooling after heating in step S103 may be allowed to cool naturally, but it is preferable that the time required for the temperature to drop from the specified temperature to room temperature is within 10 to 50 hours.
  • the temperature drop rate (hereinafter also referred to as the cooling rate) is preferably 80°C/hour to 250°C/hour, more preferably 180°C/hour to 210°C/hour.
  • the cooling rate in step S103 is preferably faster than that in step S13.
  • a fast cooling rate is called rapid cooling.
  • the partial pressure of fluorine or fluorine compounds due to the fluorine source, etc. within an appropriate range. It is also possible to control the partial pressure by placing a lid on the crucible used in this step and heating it. As described above, the lid can prevent the material from volatilizing or sublimating. Therefore, it is not necessary to seal the crucible with a lid as long as it is possible to prevent the material from volatilizing or sublimating during the temperature increase and decrease in this step. For example, by filling the reaction chamber in which the crucible is placed with oxygen, it is also possible to carry out this step without sealing the crucible. A positive electrode active material having an appropriate amount of fluorine or fluorine compounds is preferable because it can suppress heat generation and smoke generation even in the event of an internal short circuit.
  • some materials for example LiF, which is a fluorine source, may function as a flux.
  • This function allows the heating temperature to be lowered to below the melting point of lithium cobalt oxide, for example to 742°C or higher and 950°C or lower, and additive elements such as magnesium can be distributed in the surface layer to produce a positive electrode active material with good characteristics.
  • LiF has a lower specific gravity in a gaseous state than oxygen
  • LiF may volatilize when heated, and the amount of LiF in the mixture 903 will decrease if LiF volatilizes. This weakens the function as a flux. Therefore, it is necessary to heat while suppressing the volatilization of LiF.
  • LiF is not used as the fluorine source, etc.
  • Li on the LiCoO2 surface may react with F of the fluorine source to generate LiF, which may volatilize. Therefore, even if a fluorine compound with a melting point higher than LiF is used, it is necessary to suppress the volatilization in the same way.
  • the mixture 903 it is preferable to heat the mixture 903 in an atmosphere containing LiF, that is, to heat the mixture 903 in a state where the partial pressure of LiF in the heating furnace is high. By heating in this manner, it is possible to suppress the volatilization of LiF in the mixture 903. It is also preferable to place a lid on the crucible in order to suppress the volatilization of LiF.
  • the heating in this process is preferably performed so that the particles of mixture 903 do not stick to each other. If the particles of mixture 903 stick to each other during heating, the contact area with oxygen in the atmosphere decreases, and the route along which the added element (e.g., fluorine) diffuses is blocked, which may result in poor distribution of the added element (e.g., magnesium and fluorine) in the surface layer. In order to promote the reaction with oxygen in the atmosphere, the crucible does not need to be sealed with a lid.
  • the added element e.g., fluorine
  • the additive element e.g., fluorine
  • a smooth positive electrode active material with few irregularities can be obtained. Therefore, in order to maintain the smooth state of the surface after the heating in step S15 in this process, or to make it even smoother, it is better for the particles of mixture 903 not to stick together.
  • the flow rate of the oxygen-containing atmosphere in the kiln When heating in a rotary kiln, it is preferable to control the flow rate of the oxygen-containing atmosphere in the kiln. For example, it is preferable to reduce the flow rate of the oxygen-containing atmosphere, or to first purge the atmosphere and not flow the atmosphere after introducing the oxygen atmosphere into the kiln. Flowing oxygen can cause the fluorine source to evaporate, which is not preferable in terms of maintaining the smoothness of the surface.
  • the mixture 903 can be heated in an atmosphere containing LiF by, for example, placing a lid on the container containing the mixture 903. This is similar to the lid placed on a crucible.
  • the heating time varies depending on conditions such as the heating temperature, the size of the lithium cobalt oxide obtained in step S14, and the composition. When the lithium cobalt oxide is small, a lower temperature or a shorter heating time may be more preferable than when the lithium cobalt oxide is large.
  • the heating temperature is preferably, for example, 650° C. or more and 950° C. or less.
  • the heating time is preferably, for example, 3 hours or more and 60 hours or less, more preferably 10 hours or more and 30 hours or less, and even more preferably about 20 hours.
  • the cooling time after heating is preferably, for example, 10 hours or more and 50 hours or less.
  • the heating temperature is preferably, for example, 650° C. or more and 950° C. or less.
  • the heating time is preferably, for example, 1 hour or more and 10 hours or less, and more preferably about 5 hours.
  • the cooling time after heating is preferably, for example, 10 hours or more and 50 hours or less.
  • Step S104> 17A the heated material is collected and crushed as necessary to obtain the positive electrode active material 100. At this time, the collected particles may be sieved. Through the above steps, the positive electrode active material 100 according to one embodiment of the present invention can be produced.
  • the positive electrode active material according to one embodiment of the present invention has a smooth surface.
  • Method of manufacturing positive electrode active material 5 19 to 20C , a description will be given of a method 5 for producing a positive electrode active material, which is an embodiment of the present invention and is different from the method 4 for producing a positive electrode active material.
  • the method 5 for producing a positive electrode active material differs from the method 4 for producing a positive electrode active material mainly in the number of times that the additive elements are added and the mixing method. For other descriptions, the description of the method 4 can be referred to.
  • steps S11 to S15 are performed in the same manner as in FIG. 17A to prepare lithium cobalt oxide that has undergone initial heating.
  • Step S20a Next, as shown in step S20a, it is preferable to prepare an additive element A1 to be added to the lithium cobalt oxide that has been subjected to the initial heating.
  • a first additive element source is prepared.
  • the first additive element source can be selected from the additive elements A described in step S21 shown in Fig. 17B.
  • the additive element A1 can be one or more selected from magnesium, fluorine, and calcium.
  • Fig. 20A illustrates an example in which a magnesium source (Mg source) and a fluorine source (F source) are used as the first additive element source.
  • Steps S21 to S23 shown in FIG. 20A can be performed under the same conditions as steps S21 to S23 shown in FIG. 17B.
  • an additive element source (A1 source) can be obtained in step S23.
  • steps S101 to S103 shown in FIG. 19 can be performed in the same manner as steps S101 to S103 shown in FIG. 17A.
  • step S33 the heated material is collected to produce lithium cobalt oxide containing the additive element A1. To distinguish this from the composite oxide in step S14, this is also called a second composite oxide.
  • step S110 shown in Fig. 19 the additive element A2 is prepared.
  • the procedure for preparing the additive element A2 will be described with reference to Figs. 20B and 20C.
  • a second additive element source is prepared.
  • the second additive element source can be selected from the additive elements A described in step S21 shown in Fig. 17C.
  • the additive element A2 can be one or more selected from nickel, titanium, boron, zirconium, and aluminum.
  • Fig. 20B illustrates an example in which a nickel source (Ni source) and an aluminum source (Al source) are used as the second additive element source.
  • Steps S111 to S113 shown in FIG. 20B can be performed under the same conditions as steps S21 to S23 shown in FIG. 17B.
  • an additive element source (A2 source) can be obtained in step S113.
  • FIG. 20C shows a modified example of the steps described with reference to FIG. 20B.
  • step S111 shown in FIG. 20C a nickel source (Ni source) and an aluminum source (Al source) are prepared, and in step S112a, they are each crushed independently.
  • step S113 multiple second additive element sources (A2 sources) are prepared.
  • the steps in FIG. 20C differ from FIG. 20B in that the additive elements are crushed independently in step S112a.
  • steps S121 to S124 shown in Fig. 19 can be performed under the same conditions as steps S101 to S104 shown in Fig. 17A.
  • the conditions for step S123 relating to the heating step may be a lower temperature and a shorter time than those for step S103.
  • the positive electrode active material 100 according to one embodiment of the present invention can be produced.
  • the positive electrode active material according to one embodiment of the present invention has a smooth surface.
  • the additive element is introduced into lithium cobalt oxide in two parts, additive element A1 and additive element A2.
  • the location of each additive element in the depth direction can be changed. For example, it is possible to position additive element A1 so that it has a higher concentration in the surface layer than in the interior, and to position additive element A2 so that it has a higher concentration in the interior than in the surface layer.
  • the initial heating shown in this embodiment is performed on lithium cobalt oxide. Therefore, the initial heating is preferably performed under conditions that are lower than the heating temperature for obtaining lithium cobalt oxide and shorter than the heating time for obtaining lithium cobalt oxide.
  • the step of adding an additive element to lithium cobalt oxide is preferably performed after the initial heating. This addition step can be divided into two or more steps. Following this order of steps is preferable because it maintains the smoothness of the surface obtained by the initial heating.
  • Positive electrode active material 100 with a smooth surface may be more resistant to physical destruction caused by pressure, etc., than positive electrode active material that does not have a smooth surface.
  • the positive electrode active material 100 is less likely to be destroyed in a test involving pressure, such as a nail penetration test, which may result in increased safety.
  • This embodiment can be used in combination with other embodiments.
  • an all-solid-state battery will be described as a battery cell that can be applied to the above embodiment.
  • the all-solid-state battery using the positive electrode active material described in this embodiment can be applied to a room temperature battery or a low temperature battery unless otherwise specified.
  • the battery cell 400 of one embodiment of the present invention is an all-solid-state battery and has a positive electrode 410, a solid electrolyte layer 420, and a negative electrode 430.
  • the positive electrode 410 has a positive electrode current collector 413 and a positive electrode active material layer 414.
  • the positive electrode active material layer 414 has a positive electrode active material 411 and a solid electrolyte 421.
  • the positive electrode active material layer 414 may also have a conductive additive and a binder.
  • the solid electrolyte layer 420 has a solid electrolyte 421.
  • the solid electrolyte layer 420 is located between the positive electrode 410 and the negative electrode 430, and is a region that has neither the positive electrode active material 411 nor the negative electrode active material 431.
  • the negative electrode 430 has a negative electrode current collector 433 and a negative electrode active material layer 434.
  • the negative electrode active material layer 434 has a negative electrode active material 431 and a solid electrolyte 421.
  • the negative electrode active material layer 434 may also have a conductive additive and a binder.
  • metallic lithium is used as the negative electrode active material 431, it is not necessary to make it into particles, so the negative electrode 430 can be made without a solid electrolyte 421, as shown in FIG. 21B. Using metallic lithium for the negative electrode 430 is preferable because it can improve the energy density of the battery cell 400.
  • the solid electrolyte 421 in the solid electrolyte layer 420 may be, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or the like.
  • sulfide-based solid electrolytes include thiolithium - based electrolytes ( Li10GeP2S12 , Li3.25Ge0.25P0.75S4 , etc. ) , sulfide glass ( 70Li2S.30P2S530Li2S.26B2S3.44LiI , 63Li2S.36SiS2.1Li3PO4 , 57Li2S.38SiS2.5Li4SiO4 , 50Li2S.50GeS2 , etc. ) , and sulfide crystallized glass (Li7P3S11 , Li3.25P0.95S4 , etc. ) .
  • Sulfide-based solid electrolytes have the advantages of being highly conductive, being able to be synthesized at low temperatures, and being relatively soft, which makes it easier to maintain conductive paths even after charging and discharging.
  • oxide-based solid electrolytes include materials having a perovskite crystal structure ( La2/3- xLi3xTiO3 , etc.), materials having a NASICON crystal structure (Li1 - YAlYTi2 -Y ( PO4 ) 3 , etc.), materials having a garnet crystal structure ( Li7La3Zr2O12 , etc.), materials having a LISICON crystal structure ( Li14ZnGe4O16 , etc. ), LLZO ( Li7La3Zr2O12 ) , oxide glass ( Li3PO4 - Li4SiO4 , 50Li4SiO4.50Li3BO3 , etc.
  • Oxide-based solid electrolytes have the advantage of being stable in the air .
  • halide-based solid electrolytes include LiAlCl 4 , Li 3 InBr 6 , LiF, LiCl, LiBr, LiI, etc. Also, composite materials in which these halide-based solid electrolytes are filled into the pores of porous aluminum oxide or porous silica can be used as solid electrolytes.
  • Li1 + xAlxTi2 -x ( PO4 ) 3 (0 ⁇ x ⁇ 1) (hereinafter, LATP) having a NASICON crystal structure contains aluminum and titanium, which are elements that may be contained in the positive electrode active material used in the battery cell of one embodiment of the present invention, and is therefore preferable because it is expected to have a synergistic effect in improving cycle characteristics. In addition, it is expected to improve productivity by reducing the number of steps.
  • the NASICON crystal structure refers to a compound represented by M2 ( XO4 ) 3 (M: transition metal, X: S, P, As, Mo, W, etc.), which has a structure in which MO6 octahedrons and XO4 tetrahedrons are arranged three-dimensionally with vertices shared.
  • ⁇ Laminated battery cell> 22A and 22B is a laminated type battery cell having a positive electrode 503, a negative electrode 506, a separator 507, an outer casing 509, a positive electrode lead electrode 510, and a negative electrode lead electrode 511.
  • Figure 22A shows the external appearance of the positive electrode 503 and the negative electrode 506.
  • the positive electrode 503 has a positive electrode collector 550, and a positive electrode active material layer 571 is formed on the surface of the positive electrode collector 550.
  • the positive electrode 503 also has a region where the positive electrode collector 550 is partially exposed (hereinafter referred to as a tab region).
  • the negative electrode 506 has a negative electrode collector, and a negative electrode active material layer is formed on the surface of the negative electrode collector.
  • the negative electrode 506 also has a region where the negative electrode collector is partially exposed, i.e., a tab region. Note that the area or shape of the tab region of the positive electrode and the negative electrode is not limited to the example shown in Figure 22A.
  • the negative electrode 506, the separator 507, and the positive electrode 503 are laminated.
  • an example is shown in which five pairs of negative electrodes and four pairs of positive electrodes are used. It can also be called a laminate consisting of a negative electrode, a separator, and a positive electrode.
  • the tab regions of the positive electrodes 503 are joined together, and the positive electrode lead electrode 510 is joined to the tab region of the outermost positive electrode.
  • ultrasonic welding or the like may be used for the joining.
  • the tab regions of the negative electrodes 506 are joined together, and the negative electrode lead electrode 511 is joined to the tab region of the outermost negative electrode.
  • the negative electrode 506, the separator 507, and the positive electrode 503 are placed on the outer casing 509.
  • the exterior body 509 is folded at the portion indicated by the dashed line. After that, the outer periphery of the exterior body 509 is joined.
  • the joining for example, thermocompression bonding or the like may be used.
  • an area (hereinafter referred to as an inlet) that is not joined is provided on a part (or one side) of the exterior body 509 so that the electrolyte can be introduced later.
  • an electrolyte (not shown) is introduced into the inside of the exterior body 509 through an inlet provided in the exterior body 509.
  • the electrolyte is preferably introduced under a reduced pressure atmosphere or an inert atmosphere.
  • the inlet is joined. In this manner, a laminated battery cell can be produced.
  • the secondary battery 913 shown in FIG. 24A is a rectangular battery cell, and has a wound body 950 in which terminals 951 and 952 are provided inside a housing 930.
  • the wound body 950 is immersed in an electrolyte inside the housing 930.
  • the terminal 952 contacts the housing 930, and the terminal 951 does not contact the housing 930 by using an insulating material or the like.
  • the housing 930 is shown separated for convenience, but in reality, the wound body 950 is covered by the housing 930, and the terminals 951 and 952 extend outside the housing 930.
  • the housing 930 can be made of a metal material (e.g., aluminum) or a laminate of a metal material and a resin material.
  • the housing 930 shown in FIG. 24A may be formed from a plurality of materials.
  • the secondary battery 913 shown in FIG. 24B has housings 930a and 930b bonded together, and a wound body 950 is provided in the area surrounded by the housings 930a and 930b.
  • the housing 930a can be made of a metal material (such as aluminum) or a laminate of a metal material and a resin material. In particular, by using a resin material on the surface on which the antenna is formed, it is possible to suppress shielding of the electric field by the secondary battery 913. Note that if the shielding of the electric field by the housing 930a is small, the antenna may be provided inside the housing 930a.
  • the housing 930b can be made of a metal material (such as aluminum) or a laminate of a metal material and a resin material.
  • the wound body 950 has a negative electrode 931, a positive electrode 932, and a separator 933.
  • the wound body 950 is a wound body in which the negative electrode 931 and the positive electrode 932 are stacked on top of each other with the separator 933 in between, and the laminated sheet is wound. Note that the stack of the negative electrode 931, the positive electrode 932, and the separator 933 may be stacked multiple times.
  • the rectangular battery cell may be a secondary battery 913 having a wound body 950a as shown in Figs. 25A to 25C.
  • the wound body 950a shown in Fig. 25A has a negative electrode 931, a positive electrode 932, and a separator 933.
  • the negative electrode 931 has a negative electrode active material layer 931a.
  • the positive electrode 932 has a positive electrode active material layer 932a.
  • the separator 933 has a width wider than the negative electrode active material layer 931a and the positive electrode active material layer 932a, and is wound so as to overlap the negative electrode active material layer 931a and the positive electrode active material layer 932a. From the viewpoint of safety, it is preferable that the width of the negative electrode active material layer 931a is wider than that of the positive electrode active material layer 932a. Furthermore, a wound body 950a having such a shape is preferable because of its good safety and productivity.
  • the negative electrode 931 is electrically connected to terminal 951.
  • Terminal 951 is electrically connected to terminal 911a.
  • the positive electrode 932 is electrically connected to terminal 952.
  • Terminal 952 is electrically connected to terminal 911b.
  • the wound body 950a and the electrolyte are covered by the housing 930 to form the secondary battery 913. It is preferable to provide the housing 930 with a safety valve, an overcurrent protection element, and the like.
  • the safety valve is a valve that opens when the inside of the housing 930 reaches a certain internal pressure to prevent the battery from exploding.
  • the secondary battery 913 may have multiple wound bodies 950a. By using multiple wound bodies 950a, the secondary battery 913 can have a larger discharge capacity.
  • the secondary battery 913 shown in FIGS. 25A and 25B refer to the description of the secondary battery 913 shown in FIGS. 24A to 24C.
  • the secondary battery 600 shown in Fig. 26A is a cylindrical battery cell.
  • Fig. 26B is a schematic diagram showing a cross section of the secondary battery 600.
  • the secondary battery 600 has a positive electrode cap (battery lid) 601 on the top surface, and a battery can (external can) 602 on the side and bottom surfaces.
  • the positive electrode cap and the battery can (external can) 602 are insulated by a gasket (insulating packing) 610.
  • a battery element Inside the hollow cylindrical battery can 602, a battery element is provided in which a strip-shaped positive electrode 604 and a negative electrode 606 are wound with a separator 605 sandwiched between them. Although not shown, the battery element is wound around a center pin. One end of the battery can 602 is closed and the other end is open.
  • metals such as nickel, aluminum, and titanium that are resistant to corrosion by the electrolyte, or alloys of these metals, or alloys of these metals with other metals (e.g., stainless steel, etc.) can be used.
  • the battery element in which the positive electrode, negative electrode, and separator are wound is sandwiched between a pair of opposing insulating plates 608 and 609.
  • a nonaqueous electrolyte (not shown) is injected into the inside of the battery can 602 in which the battery element is provided.
  • a positive electrode terminal (positive electrode current collector lead) 603 is connected to the positive electrode 604, and a negative electrode terminal (negative electrode current collector lead) 607 is connected to the negative electrode 606.
  • the positive electrode terminal 603 can be made of a metal material such as aluminum.
  • the negative electrode terminal 607 can be made of a metal material such as copper.
  • the positive electrode terminal 603 is resistance-welded to a safety valve mechanism 612, and the negative electrode terminal 607 is resistance-welded to the bottom of the battery can 602.
  • the safety valve mechanism 612 is electrically connected to the positive electrode cap 601 via a PTC (Positive Temperature Coefficient) element 611.
  • the safety valve mechanism 612 cuts off the electrical connection between the positive electrode cap 601 and the positive electrode 604 when the rise in the internal pressure of the battery exceeds a predetermined threshold value.
  • the PTC element 611 is a thermosensitive resistor whose resistance increases when the temperature rises, and the increase in resistance limits the amount of current to prevent abnormal heat generation. Barium titanate (BaTiO 3 ) based semiconductor ceramics or the like can be used for the PTC element.
  • multiple secondary batteries 600 may be sandwiched between conductive plates 613 and 614 to form an assembled battery 615.
  • the multiple secondary batteries 600 may be connected in parallel, in series, or in parallel and then further in series.
  • the battery pack may include the assembled battery 615, a BMS, a temperature sensor, etc.
  • FIG 26D is a top view of the battery pack 615.
  • the conductive plate 613 is shown with a dotted line.
  • the battery pack 615 may have a conductor 616 that electrically connects the multiple secondary batteries 600.
  • a conductive plate can be superimposed on the conductor 616.
  • a cooling device 617 may also be provided between the multiple secondary batteries 600 as a temperature control device. When the secondary batteries 600 overheat, they can be cooled by the cooling device 617. If a heating device is used as a temperature control device, the secondary batteries 600 can also be heated when they are too cold. This makes the performance of the battery pack 615 less susceptible to the effects of the outside air temperature.
  • the automobile 8400 shown in FIG. 27A is an electric vehicle (EV) that uses an electric motor as a power source for traveling.
  • the automobile 8400 preferably has a battery control system, which is one aspect of the present invention, and controls the charging and discharging of the battery.
  • the power of the battery is used to drive the electric motor 8406, but may also be used to supply power to a light-emitting device such as a headlight 8401 or a room light (not shown).
  • a light-emitting device such as a headlight 8401 or a room light (not shown).
  • power may also be supplied from a 12V battery to a light-emitting device such as a headlight 8401 or a room light (not shown).
  • the power of the battery may be used to supply power to display devices such as a speedometer and a tachometer of the automobile 8400.
  • power may be supplied to display devices such as a speedometer and a tachometer from a 12V battery.
  • the power of the battery may be used to supply power to semiconductor devices such as a navigation system included in the automobile 8400.
  • power may be supplied to semiconductor devices such as a navigation system from a 12V battery.
  • the automobile 8500 shown in FIG. 27B is a plug-in hybrid vehicle (PHV), and is an example of a hybrid vehicle that can charge the battery of the automobile 8500 by receiving power from an external charging facility using a plug-in method or a contactless power supply method.
  • the automobile 8500 preferably has a battery control system, which is one aspect of the present invention, and controls the charging and discharging of the battery.
  • FIG. 27B shows a state in which a battery 8024 (including a first battery and a second battery) mounted on an automobile 8500 is being charged via a cable 8022 from a ground-mounted charging stand 8021.
  • the charging stand 8021 may be a charging station provided in a commercial facility, or may be a home power source.
  • the battery 8024 mounted on the automobile 8500 can be charged by an external power supply. Charging can be performed by converting AC power to DC power via a conversion device such as an AC-DC converter.
  • the conversion device such as an AC-DC converter may be provided in the automobile 8500 or in the charging stand 8021.
  • the charging stand 8021 is provided with the conversion device, rapid charging becomes possible. Note that the description regarding the charging stand 8021 can be applied to the automobile 8400 shown in FIG. 27A.
  • charging can be performed by supplying power contactlessly from a ground power transmission device.
  • this contactless power supply method by incorporating a power transmission device into a road or an exterior wall, charging can be performed not only while the vehicle is stopped but also while it is moving.
  • This contactless power supply method can also be used to transmit and receive power between vehicles.
  • a solar cell can be provided on the exterior of the vehicle to charge the secondary battery when the vehicle is stopped or moving.
  • An electromagnetic induction method or a magnetic field resonance method can be used for such contactless power supply. Note that the explanation regarding contactless transmission and reception of power can be applied to the automobile 8400 shown in FIG. 27A.
  • FIG. 27C shows a scooter 8600, which is an example of a two-wheeled vehicle.
  • the scooter 8600 preferably has a battery control system, which is one aspect of the present invention, and controls the charging and discharging of the battery.
  • the scooter 8600 includes a battery 8602 (including a first battery and a second battery), a side mirror 8601, and a turn signal light 8603.
  • the battery 8602 can supply electricity to the turn signal light 8603.
  • the turn signal light 8603 may be supplied with power from a 12V battery.
  • the scooter 8600 shown in FIG. 27C can also store a battery 8602 in the under-seat storage 8604.
  • the battery 8602 is preferably equipped with a removable mechanism, in which case the battery 8602 can be brought indoors for charging, charged, and then stored in the under-seat storage 8604 before riding.
  • the house 2600 shown in FIG. 28 is electrically connected to the batteries (including a first battery and a second battery) of the vehicle 2603 via a converter 2604.
  • the converter 2604 has a function of converting the direct current of the battery of the vehicle 2603 into alternating current for the house 2600.
  • the power of the battery of the vehicle 2603 can be used by the house 2600.
  • the vehicle 2603 which is one embodiment of the present invention, can perform vehicle-to-home by being equipped with the converter 2604.
  • the house 2600 preferably has a power storage device 2612 and a solar panel 2610.
  • the power storage device 2612 is electrically connected to the solar panel 2610 via wiring 2611 or the like.
  • the power storage device 2612 is preferably installed in the underfloor space. By installing it in the underfloor space, the space above the floor can be effectively used. Alternatively, the power storage device 2612 may be installed on the floor.
  • the power storage device 2612 is also electrically connected to the converter 2604.
  • the power storage device 2612 may be equipped with a battery control system which is one embodiment of the present invention.
  • the power obtained by the solar panel 2610 can be charged to the power storage device 2612.
  • the power stored in the power storage device 2612 can also be stored in a battery in the vehicle 2603 via the converter 2604.
  • the power stored in the power storage device 2612 can also be supplied to other electronic devices in the house 2600.
  • Vehicle-to-home makes it possible to use other electronic devices in the house 2600 even when power cannot be supplied from the commercial power source due to a power outage or other reason.
  • Battery control system 11 electric vehicle, 12: charging control circuit, 13: tire, 14: motor control circuit, 15: drive motor, 18: converter, 19a: normal charging port, 19b: quick charging port, 19: charging port, 21: VCU, 25: CAN, 23: headlight, 24: auxiliary battery, 27: chassis, 28: container, 30: charging stand, 31: AC power source, 33: converter, 34: inverter, 35: transformer circuit, 36: rectifier circuit, 37: connector, 51: single cell, 52: battery pack, 101a: first battery, 101b: second battery, 101: battery, 102a: first sensor circuit, 102b: second sensor circuit, 103a: first voltage sensor, 103b: second voltage sensor, 104a: first current sensor, 104b: second current sensor, 106a: first circuit, 106b: second circuit, 107a: first DC/DC circuit, 107b: second DC/DC circuit, 108a: first diode, 108b: second diode, 150a: micro

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Abstract

This battery control system suppresses degradation of batteries. The battery control system comprises: a first battery having a first positive electrode active material; a second battery having a second positive electrode active material; a first sensor circuit that is electrically connected to the first battery; a second sensor circuit that is electrically connected to the second battery; a first DC/DC converter that is electrically connected to the first battery; a second DC/DC converter that is electrically connected to the second battery; and a microcomputer that is electrically connected to the first sensor circuit, the second sensor circuit, the first DC/DC converter, and the second DC/DC converter. The microcomputer has a function for determining, on the basis of a signal acquired from the first sensor circuit or the second sensor circuit, output from the first DC/DC converter to a motor control circuit and output from the second DC/DC converter to the motor control circuit.

Description

バッテリ制御システム及び車両Battery control system and vehicle
本発明は、バッテリ制御システム又はバッテリ制御システムを搭載した車両に関する。 The present invention relates to a battery control system or a vehicle equipped with a battery control system.
また、本発明は、上記技術分野に限定されず、バッテリ制御システムを搭載した電子機器に関する。また、本発明は、バッテリ制御システムを搭載した蓄電装置に関する。なお本明細書等において、蓄電装置には据置型の蓄電装置が含まれる。 The present invention is not limited to the above technical fields, but also relates to an electronic device equipped with a battery control system. The present invention also relates to a power storage device equipped with a battery control system. Note that in this specification, power storage devices include stationary power storage devices.
二次電池は、繰り返し利用可能なエネルギー源として現代社会に不可欠なものとなっている。キャリアイオンとしてリチウムイオンを有する二次電池をリチウムイオン二次電池又はリチウムイオン電池と呼ぶ。なお、本明細書等では二次電池をバッテリと記し、断りがない限りバッテリには一次電池が含まれない。 Secondary batteries have become indispensable in modern society as a reusable energy source. A secondary battery that has lithium ions as the carrier ion is called a lithium-ion secondary battery or lithium-ion battery. Note that in this specification, secondary batteries are referred to as batteries, and unless otherwise specified, batteries do not include primary batteries.
電気自動車は、バッテリに蓄えられた電気を動力源として、モータで走行する自動車である。モータに十分な動力を提供するため、バッテリは組電池（単電池が複数集まったもの）が採用されている。 An electric vehicle is a vehicle that runs on a motor powered by electricity stored in a battery. In order to provide sufficient power for the motor, a battery pack (a collection of multiple single cells) is used as the battery.
組電池は容器に収容された状態（この状態をバッテリパックとも呼ぶ）で車体に搭載されることが多い。容器に収容されることで、組電池を他の車両部品と切り分けることができ、組電池の温度管理が簡便になる。一方、軽量化等を目的として、組電池を容器に収容することなく、車両シャーシに固定する構造（セルトゥーシャーシ構造とも呼ぶ）が提案されている（特許文献１参照）。 Batteries are often mounted on a vehicle body housed in a container (also called a battery pack). By housing the battery in a container, it is possible to separate the battery from other vehicle components, making it easier to manage the temperature of the battery. On the other hand, in order to reduce weight, etc., a structure has been proposed in which the battery is fixed to the vehicle chassis without being housed in a container (also called a cell-to-chassis structure) (see Patent Document 1).
特表２０２１−５１２００９号公報JP 2021-512009 A
しかしながら、上記特許文献１のように車両シャーシに固定されたバッテリは、バッテリパックと比べて、バッテリが温度の影響を受けやすく劣化しやすいことが課題となる。 However, a battery fixed to the vehicle chassis as in Patent Document 1 above has the problem that the battery is more susceptible to temperature effects and degradation than a battery pack.
なお、上記課題の記載は、他の課題の存在を妨げるものではない。なお、明細書、図面、請求項（明細書等と記す）の記載から、これら以外の課題を抽出することも可能である。 Note that the description of the above problems does not preclude the existence of other problems. It is also possible to extract other problems from the description of the specification, drawings, and claims (hereinafter referred to as the specification, etc.).
上記記載を鑑み本発明の一態様は、バッテリの劣化を抑制するべく新たな構成を備えたバッテリ、及びバッテリ制御システムを提供する。また本発明の一態様は、車両シャーシに固定されたバッテリの劣化を抑制するべく、新たなバッテリを搭載した車載用バッテリを提供する。さらに本発明の一態様は、上述したような二以上のバッテリを制御するバッテリ制御システムを提供する。なお、車両シャーシに固定されたバッテリを第１のバッテリと呼ぶとき、新たなバッテリは第２のバッテリと呼ぶことがある。 In view of the above, one aspect of the present invention provides a battery and a battery control system with a new configuration to suppress battery deterioration. Another aspect of the present invention provides an in-vehicle battery equipped with a new battery to suppress deterioration of a battery fixed to a vehicle chassis. A further aspect of the present invention provides a battery control system that controls two or more batteries as described above. Note that when the battery fixed to the vehicle chassis is referred to as the first battery, the new battery may be referred to as the second battery.
本発明では第１のバッテリの劣化を第２のバッテリで抑制することができる限りにおいて、第１のバッテリ及び第２のバッテリについて、車両への搭載の仕方は何ら限定されるものではない。すなわち本発明において、第１のバッテリ及び第２のバッテリがともにバッテリパックで車両へ搭載されてもよい。 In the present invention, as long as the deterioration of the first battery can be suppressed by the second battery, there is no limitation on the way in which the first battery and the second battery are mounted on the vehicle. In other words, in the present invention, both the first battery and the second battery may be mounted on the vehicle as a battery pack.
本発明の一態様は、第１の正極活物質を有する第１のバッテリと、第２の正極活物質を有する第２のバッテリと、第１のバッテリと電気的に接続された、第１のセンサ回路と、第２のバッテリと電気的に接続された、第２のセンサ回路と、第１のバッテリと電気的に接続された、第１のＤＣ／ＤＣコンバータと、第２のバッテリと電気的に接続された、第２のＤＣ／ＤＣコンバータと、第１のセンサ回路、第２のセンサ回路、第１のＤＣ／ＤＣコンバータ、及び第２のＤＣ／ＤＣコンバータと電気的に接続された、マイコンと、を有し、マイコンは、第１のセンサ回路、又は第２のセンサ回路から得られた信号に基づき、第１のＤＣ／ＤＣコンバータからのモータ制御回路への出力と、第２のＤＣ／ＤＣコンバータからのモータ制御回路への出力とを決定する機能を有する、バッテリ制御システムである。 One aspect of the present invention is a battery control system that includes a first battery having a first positive electrode active material, a second battery having a second positive electrode active material, a first sensor circuit electrically connected to the first battery, a second sensor circuit electrically connected to the second battery, a first DC/DC converter electrically connected to the first battery, a second DC/DC converter electrically connected to the second battery, and a microcomputer electrically connected to the first sensor circuit, the second sensor circuit, the first DC/DC converter, and the second DC/DC converter, and the microcomputer has a function of determining the output from the first DC/DC converter to the motor control circuit and the output from the second DC/DC converter to the motor control circuit based on a signal obtained from the first sensor circuit or the second sensor circuit.
本発明の別の一態様は、第１の正極活物質を有する第１のバッテリと、第２の正極活物質を有する第２のバッテリと、第１のバッテリと電気的に接続された、第１のセンサ回路と、第２のバッテリと電気的に接続された、第２のセンサ回路と、第１のバッテリと電気的に接続された、第１のＤＣ／ＤＣコンバータと、第２のバッテリと電気的に接続された、第２のＤＣ／ＤＣコンバータと、第１のセンサ回路、第２のセンサ回路、第１のＤＣ／ＤＣコンバータ、及び第２のＤＣ／ＤＣコンバータと電気的に接続された、マイコンと、マイコンと電気的に接続された保護ＩＣと、を有し、マイコンは、第１のセンサ回路、又は第２のセンサ回路から得られた信号に基づき、第１のＤＣ／ＤＣコンバータからのモータ制御回路への出力と、第２のＤＣ／ＤＣコンバータからのモータ制御回路への出力とを決定する機能を有する、バッテリ制御システムである。 Another aspect of the present invention is a battery control system having a first battery having a first positive electrode active material, a second battery having a second positive electrode active material, a first sensor circuit electrically connected to the first battery, a second sensor circuit electrically connected to the second battery, a first DC/DC converter electrically connected to the first battery, a second DC/DC converter electrically connected to the second battery, a microcontroller electrically connected to the first sensor circuit, the second sensor circuit, the first DC/DC converter, and the second DC/DC converter, and a protection IC electrically connected to the microcontroller, the microcontroller having a function of determining the output from the first DC/DC converter to the motor control circuit and the output from the second DC/DC converter to the motor control circuit based on a signal obtained from the first sensor circuit or the second sensor circuit.
本発明の別の一態様において、マイコン及び保護ＩＣを有するバッテリマネジメントシステムを有すると好ましい。 In another aspect of the present invention, it is preferable to have a battery management system having a microcontroller and a protection IC.
本発明の別の一態様において、保護ＩＣは第１のバッテリが有する単電池、又は第２のバッテリが有する単電池と電気的に接続されていると好ましい。 In another aspect of the present invention, it is preferable that the protection IC is electrically connected to a single cell of the first battery or a single cell of the second battery.
本発明の別の一態様において、第１の正極活物質はオリビン型の結晶構造を有し、第２の正極活物質は層状岩塩型の結晶構造を有すると好ましい。 In another aspect of the present invention, it is preferable that the first positive electrode active material has an olivine type crystal structure, and the second positive electrode active material has a layered rock salt type crystal structure.
本発明の別の一態様において、さらに第１の回路及び第２の回路を有し、第１の回路は、第１のバッテリと、充電制御回路との間に位置し、第２の回路は、第２のバッテリと、充電制御回路との間に位置し、第１の回路及び第２の回路は、第１のバッテリの電力を第２のバッテリへ転送する機能を有すると好ましい。 In another aspect of the present invention, the battery further includes a first circuit and a second circuit, the first circuit being located between the first battery and the charging control circuit, and the second circuit being located between the second battery and the charging control circuit, and the first circuit and the second circuit preferably having a function of transferring power from the first battery to the second battery.
本発明の別の一態様において、さらに第１の回路及び第２の回路を有し、第１の回路は、第１のバッテリと、充電制御回路との間に位置し、第２の回路は、第２のバッテリと、充電制御回路との間に位置し、第１の回路及び第２の回路は、第２のバッテリの電力を第１のバッテリへ転送する機能を有すると好ましい。 In another aspect of the present invention, the battery further includes a first circuit and a second circuit, the first circuit being located between the first battery and the charging control circuit, the second circuit being located between the second battery and the charging control circuit, and the first circuit and the second circuit preferably having a function of transferring power from the second battery to the first battery.
本発明の別の一態様において、第１のセンサ回路は、第１のバッテリが有する単電池と電気的に接続された、第１の電流センサを有すると好ましい。 In another aspect of the present invention, the first sensor circuit preferably has a first current sensor electrically connected to a single cell of the first battery.
本発明の別の一態様において、第１のセンサ回路は、第１のバッテリが有する単電池と電気的に接続された、第１の電圧センサを有すると好ましい。 In another aspect of the present invention, the first sensor circuit preferably has a first voltage sensor electrically connected to a single cell of the first battery.
本発明の別の一態様において、第２のセンサ回路は、第２のバッテリが有する単電池と電気的に接続された、第２の電流センサを有すると好ましい。 In another aspect of the present invention, the second sensor circuit preferably has a second current sensor electrically connected to a single cell of the second battery.
本発明の別の一態様において、第２のセンサ回路は、第２のバッテリが有する単電池と電気的に接続された、第２の電圧センサを有すると好ましい。 In another aspect of the present invention, the second sensor circuit preferably has a second voltage sensor electrically connected to a single cell of the second battery.
本発明の別の一態様において、マイコンは、第１のバッテリのｄＱ／ｄＶ曲線に基づいて、第１のＤＣ／ＤＣコンバータの出力と、第２のＤＣ／ＤＣコンバータの出力とを制御する機能を有すると好ましい。 In another aspect of the present invention, it is preferable that the microcontroller has a function of controlling the output of the first DC/DC converter and the output of the second DC/DC converter based on the dQ/dV curve of the first battery.
本発明の別の一態様において、マイコンは、第２のバッテリのｄＱ／ｄＶ曲線に基づいて、第１のＤＣ／ＤＣコンバータの出力と、第２のＤＣ／ＤＣコンバータの出力とを制御する機能を有すると好ましい。 In another aspect of the present invention, it is preferable that the microcontroller has a function of controlling the output of the first DC/DC converter and the output of the second DC/DC converter based on the dQ/dV curve of the second battery.
本発明の別の一態様は、バッテリ制御システムを搭載した車両である。 Another aspect of the present invention is a vehicle equipped with a battery control system.
本発明の一態様であるバッテリ制御システムにより、バッテリの劣化を抑制することができる。 The battery control system, which is one aspect of the present invention, can suppress battery deterioration.
なお、これらの効果の記載は、他の効果の存在を妨げるものではない。なお、本発明の一態様は、必ずしも、これらの効果の全てを有する必要はない。なお、これら以外の効果は、明細書、図面、請求項などの記載から、自ずと明らかとなるものであり、明細書、図面、請求項などの記載から、これら以外の効果を抽出することが可能である。 Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have to have all of these effects. Note that effects other than these will become apparent from the description in the specification, drawings, claims, etc., and it is possible to extract effects other than these from the description in the specification, drawings, claims, etc.
図１Ａ乃至図１Ｄは本発明の一態様である車両、及びバッテリ制御システムを説明する図である。
図２は急速充電用のスタンドの構成を説明する図である。
図３は本発明の一態様であるバッテリ制御システムを説明する図である。
図４Ａ及び図４Ｂは本発明の一態様であるＢＭＳを説明する図である。
図５は本発明の一態様であるバッテリ制御システムを説明する図である。
図６は本発明の一態様であるバッテリ制御システムを説明する図である。
図７は本発明の一態様であるバッテリ制御システムに用いられるバッテリの特性を示すグラフである。
図８Ａ乃至図８Ｂは本発明の一態様であるバッテリ制御システムに用いられるバッテリのｄＱ／ｄＶ曲線のグラフである。
図９は本発明の一態様であるバッテリ制御システムに用いられるバッテリのｄＱ／ｄＶ曲線のグラフである。
図１０は本発明の一態様であるバッテリ制御システムの手順を説明するフローチャートである。
図１１は本発明の一態様であるバッテリ制御システムの手順を説明するフローチャートである。
図１２は本発明の一態様であるバッテリ制御システムの手順を説明するフローチャートである。
図１３Ａ及び図１３Ｂは本発明の一態様である正極を説明する図である。
図１４は本発明の一態様である正極活物質の作製方法を説明する図である。
図１５は本発明の一態様である正極活物質の作製方法を説明する図である。
図１６は本発明の一態様である正極活物質の作製方法を説明する図である。
図１７Ａ乃至図１７Ｃは本発明の一態様である正極活物質の作製方法を説明する図である。
図１８Ａ乃至図１８Ｃは本発明の一態様である正極活物質の作製方法を説明する図である。
図１９は本発明の一態様である正極活物質の作製方法を説明する図である。
図２０Ａ乃至図２０Ｃは本発明の一態様である正極活物質の作製方法を説明する図である。
図２１Ａ及び図２１Ｂは本発明の一態様である電池を説明する図である。
図２２Ａ及び図２２Ｂは本発明の一態様であるラミネート型電池セルを説明する図である。
図２３Ａ及び図２３Ｂは本発明の一態様であるラミネート型電池セルの製造方法を説明する図である。
図２４Ａ乃至図２４Ｃは本発明の一態様である角型電池セルを説明する図である。
図２５Ａ乃至図２５Ｃは本発明の一態様である角型電池セルを説明する図である。
図２６Ａ乃至図２６Ｄは本発明の一態様である円筒型電池セルを説明する図である。
図２７Ａ乃至図２７Ｃは本発明の一態様である車両を説明する図である。
図２８は本発明の一態様である車両と住宅の電力授受を説明する図である。 1A to 1D are diagrams illustrating a vehicle and a battery control system according to one embodiment of the present invention.
FIG. 2 is a diagram illustrating the configuration of a quick charging stand.
FIG. 3 is a diagram illustrating a battery control system according to an embodiment of the present invention.
4A and 4B are diagrams illustrating a BMS according to one embodiment of the present invention.
FIG. 5 is a diagram illustrating a battery control system according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating a battery control system according to an embodiment of the present invention.
FIG. 7 is a graph showing the characteristics of a battery used in the battery control system according to one embodiment of the present invention.
8A and 8B are graphs of dQ/dV curves of a battery used in a battery control system according to one embodiment of the present invention.
FIG. 9 is a graph of the dQ/dV curve of a battery used in a battery control system according to one embodiment of the present invention.
FIG. 10 is a flowchart for explaining the procedure of the battery control system according to one embodiment of the present invention.
FIG. 11 is a flowchart for explaining the procedure of the battery control system according to one embodiment of the present invention.
FIG. 12 is a flowchart for explaining the procedure of the battery control system according to one embodiment of the present invention.
13A and 13B illustrate a positive electrode which is one embodiment of the present invention.
FIG. 14 is a diagram illustrating a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
FIG. 15 is a diagram illustrating a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
FIG. 16 is a diagram illustrating a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
17A to 17C illustrate a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
18A to 18C illustrate a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
FIG. 19 is a diagram illustrating a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
20A to 20C illustrate a method for manufacturing a positive electrode active material according to one embodiment of the present invention.
21A and 21B are diagrams illustrating a battery that is one embodiment of the present invention.
22A and 22B are diagrams illustrating a laminated battery cell according to one embodiment of the present invention.
23A and 23B are diagrams illustrating a method for manufacturing a laminated battery cell according to one embodiment of the present invention.
24A to 24C are diagrams illustrating a rectangular battery cell according to one embodiment of the present invention.
25A to 25C are diagrams illustrating a rectangular battery cell according to one embodiment of the present invention.
26A to 26D are diagrams illustrating a cylindrical battery cell according to one embodiment of the present invention.
27A to 27C are diagrams illustrating a vehicle according to one embodiment of the present invention.
FIG. 28 is a diagram illustrating power transfer between a vehicle and a house according to one embodiment of the present invention.
以下では、本発明を実施するための形態例について図面等を用いて説明する。ただし、本発明は以下の形態例に限定して解釈されるものではない。本発明の趣旨を逸脱しない範囲で発明を実施する形態を変更することは可能である。 The following describes examples of embodiments of the present invention with reference to the drawings. However, the present invention should not be interpreted as being limited to the following examples. The embodiments of the invention may be modified without departing from the spirit of the present invention.
本明細書等において、車両シャーシとは車体のボディ以外の部材を指し、フレームなどを含むものとする。 In this specification, the term vehicle chassis refers to components other than the body of the vehicle, including the frame, etc.
本明細書等において、組電池は複数の単電池を有するものであり、単電池の集合体といってもよい。 In this specification, a battery pack has multiple single cells and can be said to be an assembly of single cells.
本明細書等において、バッテリパックとは、上記組電池が容器に収容された状態を指す。容器はプラスチック又は金属を用いることができるが、軽量化の点、及び／又は断熱性を付与する点においてプラスチックの方が優れる材料といえる。なお組電池を監視するバッテリマネジメントシステム（ＢＭＳと記す）、及び組電池に対する冷却機構から選ばれた一以上が容器に収容されている状態、つまり組電池以外の部材が容器に収容されている場合も、バッテリパックと呼んでよい。 In this specification, the term "battery pack" refers to the battery pack housed in a container. The container can be made of plastic or metal, but plastic is a better material in terms of weight reduction and/or heat insulation. Note that the term "battery pack" may also be used when the container contains one or more components selected from a battery management system (referred to as "BMS") that monitors the battery pack and a cooling mechanism for the battery pack, that is, when components other than the battery pack are housed in the container.
本明細書等において、ＢＭＳは単電池の過充電、及び過放電を防ぐ機能を有する。またＢＭＳは単電池の過電流を防ぐ機能を有する。またＢＭＳは単電池の温度管理を行う機能を有する。またＢＭＳは単電池の充電残量（ＳＯＣ：Ｓｔａｔｅ　Ｏｆ　Ｃｈａｒｇｅ）を算出する機能を有する。充電残量は充電率又は充電状態と読み替えてよい。またＢＭＳは組電池における各単電池の電圧の均等化（これをセルバランスと呼ぶ）を行う機能を有する。このような機能の一を有するＢＭＳは、安全制御を行うシステムともいえる。 In this specification, the BMS has a function to prevent overcharging and over-discharging of the cells. The BMS also has a function to prevent overcurrent in the cells. The BMS also has a function to manage the temperature of the cells. The BMS also has a function to calculate the remaining charge (SOC: State of Charge) of the cells. The remaining charge may be interpreted as the charging rate or charging state. The BMS also has a function to equalize the voltage of each cell in the battery pack (this is called cell balancing). A BMS with one of these functions can also be said to be a system that performs safety control.
本明細書等において、ＳＯＣは単電池の電圧から求めることができる指標である。たとえば単電池の電圧が仕様の上限電圧を満たすときを充電上限状態と呼び、仕様の下限電圧を満たすときを放電下限状態と呼ぶ。ＳＯＣは充電上限状態を１００％とし、放電下限状態を０％とした百分率で示すことがあり、ＳＯＣ５０％とは充電上限状態から電圧が半減したことを指す。ただし、単電池の温度（単電池の外装体の温度と読み替えてもよい）が室温（代表的には２５℃）より高いと、充電上限状態及び放電下限状態を正確に判断しづらい場合がある。このような場合を想定して、ＳＯＣは単電池の容量から求めた指標を用いることもある。容量を用いた場合も充電上限状態を１００％とし、放電下限状態を０％とした百分率で示すことができる。 In this specification, the SOC is an index that can be calculated from the voltage of a single cell. For example, when the voltage of a single cell meets the upper limit voltage of the specification, it is called the upper limit charge state, and when it meets the lower limit voltage of the specification, it is called the lower limit discharge state. The SOC may be expressed as a percentage, with the upper limit charge state being 100% and the lower limit discharge state being 0%, and SOC 50% means that the voltage has been halved from the upper limit charge state. However, if the temperature of the single cell (which may be read as the temperature of the exterior body of the single cell) is higher than room temperature (typically 25°C), it may be difficult to accurately determine the upper limit charge state and the lower limit discharge state. In anticipation of such a case, the SOC may be an index calculated from the capacity of the single cell. When the capacity is used, it can also be expressed as a percentage, with the upper limit charge state being 100% and the lower limit discharge state being 0%.
本明細書等において、バッテリの劣化には、充放電サイクルによる劣化と、充放電サイクルに曝されずに生じる劣化とが含まれる。また本明細書等において、バッテリの定格容量の９７％以上の放電容量を有する場合は、劣化前の状態と言うことができる。また特に言及しない限り、単電池が有する材料（正極活物質、負極活物質、電解質等）は、劣化前の状態について説明するものとする。 In this specification, deterioration of a battery includes deterioration due to charge/discharge cycles and deterioration that occurs without exposure to charge/discharge cycles. In addition, in this specification, a battery that has a discharge capacity of 97% or more of its rated capacity can be said to be in a state before deterioration. Unless otherwise specified, the materials contained in the single cell (positive electrode active material, negative electrode active material, electrolyte, etc.) will be described in terms of their state before deterioration.
（実施の形態１）
本実施の形態では、本発明の一態様のバッテリ制御システムが車両に搭載された場合について説明する。本発明の一態様のバッテリ制御システムが搭載可能な車両には、電気自動車（ＥＶ）、又はプラグインハイブリッド車（ＰＨＶ）等があるが、電気自動車を用いて説明する。なお、本発明の一態様のバッテリ制御システムは、車両以外に、例えば電子機器、又は蓄電装置へ搭載することも可能である。 (Embodiment 1)
In this embodiment, a case where a battery control system according to one embodiment of the present invention is mounted on a vehicle will be described. Vehicles on which the battery control system according to one embodiment of the present invention can be mounted include electric vehicles (EVs) and plug-in hybrid vehicles (PHVs), and the electric vehicle will be used for the description. Note that the battery control system according to one embodiment of the present invention can also be mounted on, for example, electronic devices or power storage devices other than vehicles.
図１Ａに示すように、本発明の一態様の電気自動車１１は、バッテリ１０１、充電口１９、タイヤ１３、及びヘッドライト２３を有する。本発明の一態様のバッテリ１０１は二以上のバッテリを有するとよく、第１のバッテリ１０１ａと、第２のバッテリ１０１ｂとを用いて説明する。 As shown in FIG. 1A, an electric vehicle 11 according to one embodiment of the present invention has a battery 101, a charging port 19, tires 13, and a headlight 23. The battery 101 according to one embodiment of the present invention may have two or more batteries, and will be described using a first battery 101a and a second battery 101b.
本実施の形態等において、バッテリは組電池をなしているものとして、バッテリ制御システムを説明する。なお、組電池は複数の単電池の電極部を結合することで、大きな容量の一つの電池、又は高い電圧の一つの電池として機能することができる。組電池を電気自動車に搭載する場合、複数の単電池を直列接続、及び並列接続させることで、容量又は電圧が適切な値となるように調整することができる。ただし本発明は組電池に限定されるものではないため、組電池を単電池に置き換えてバッテリ制御システムを理解することができる。この場合のバッテリ制御システムは、電子機器、又は蓄電装置へ搭載されると好ましい。 In the present embodiment and the like, the battery control system will be described assuming that the battery forms a battery pack. The battery pack can function as a single large-capacity battery or a single high-voltage battery by combining the electrodes of multiple single cells. When the battery pack is installed in an electric vehicle, the capacity or voltage can be adjusted to an appropriate value by connecting multiple single cells in series and in parallel. However, the present invention is not limited to battery packs, and the battery control system can be understood by replacing the battery pack with single cells. In this case, the battery control system is preferably installed in an electronic device or a power storage device.
図１Ｂには、第１のバッテリ１０１ａが車両シャーシに固定された状態を示す。シャーシ２７には第１のバッテリ１０１ａが有する単電池５１がそれぞれ固定されている。図１Ｂに示すように、単電池５１には後述の角型電池セルの構成を適用することができる。勿論、単電池５１には後述のラミネート型電池セル、円筒型電池セルの構成を適用してもよい。第１のバッテリ１０１ａは容器がないため、軽量化と低コスト化を図ることができる。一方、容器がないため温度の管理が難しいことがあり、第１のバッテリ１０１ａは劣化しやすい環境に曝されてしまう。そこで、車両シャーシに固定された第１のバッテリ１０１ａを劣化させないバッテリとするべく、図１Ａ等で示したように第２のバッテリ１０１ｂを有することとする。さらに、車両シャーシに固定された第１のバッテリ１０１ａは、雨などによる水の影響も大きく受けるため、安全性の高いバッテリを用いると好ましい。 FIG. 1B shows the state in which the first battery 101a is fixed to the vehicle chassis. The single cells 51 of the first battery 101a are fixed to the chassis 27. As shown in FIG. 1B, the single cells 51 can be configured as rectangular battery cells, which will be described later. Of course, the single cells 51 can be configured as laminated battery cells or cylindrical battery cells, which will be described later. The first battery 101a does not have a container, so it can be lightweight and low-cost. On the other hand, since there is no container, it can be difficult to control the temperature, and the first battery 101a is exposed to an environment in which it is prone to deterioration. Therefore, in order to prevent the first battery 101a fixed to the vehicle chassis from deteriorating, the second battery 101b is provided as shown in FIG. 1A and the like. Furthermore, since the first battery 101a fixed to the vehicle chassis is greatly affected by water from rain, etc., it is preferable to use a battery with high safety.
図１Ｃには第２のバッテリ１０１ｂが収容されたバッテリパックを示す。第２のバッテリ１０１ｂは組電池５２が複数集まったものを用いると好ましく、図１Ｃでは容器２８に組電池５２が収容されている。組電池５２は単電池を有するものであり、当該単電池は後述のラミネート型電池セルの構成を適用することができる。勿論、単電池には、後述の角型電池セル、円筒型電池セルの構成を適用してもよい。組電池５２が有する容器にはプラスチック、又は金属を用いることができる。 Figure 1C shows a battery pack that houses the second battery 101b. It is preferable to use a battery pack consisting of multiple battery packs 52 as the second battery 101b, and in Figure 1C, the battery pack 52 is housed in a container 28. The battery pack 52 has single cells, and the single cells can have the laminated battery cell configuration described below. Of course, the single cells can also have the rectangular battery cell or cylindrical battery cell configuration described below. The container of the battery pack 52 can be made of plastic or metal.
なお図１Ｃでは、容器２８の一部を省略して、組電池５２を図示している。このような形態とすることで、容器２８の外の熱、つまり外温から組電池５２を遮断することが可能となる、すなわち、第２のバッテリ１０１ｂは温度管理を精度よく実行することができ、劣化しづらい環境を提供できる。さらに、バッテリパックは、交換しやすいと考えられる。 Note that in FIG. 1C, the battery pack 52 is illustrated with a portion of the container 28 omitted. This configuration makes it possible to insulate the battery pack 52 from heat outside the container 28, i.e., from the external temperature. In other words, the second battery 101b can perform temperature management with precision, providing an environment that is less prone to deterioration. Furthermore, the battery pack is considered to be easy to replace.
本発明の一態様において、上述した第２のバッテリ１０１ｂは新たに搭載したバッテリに相当し、第１のバッテリ１０１ａの補助として機能させる。別言すると第２のバッテリ１０１ｂにより、第１のバッテリ１０１ａの劣化が抑制され、第１のバッテリ１０１ａのサイクル寿命（単に寿命とも記す）を延ばすことができる。すると、電気自動車１１が廃車となるまでの期間において、第１のバッテリ１０１ａを交換せずに済む。または第１のバッテリ１０１ａの交換頻度を少なくすることができる。車両シャーシに固定された第１のバッテリ１０１ａはバッテリパックと比較して交換し難い構成であるため、第１のバッテリ１０１ａの寿命が向上することは顕著な効果を奏するといえる。勿論、本発明の一態様において、第１のバッテリ１０１ａを第２のバッテリ１０１ｂの補助として機能させることも可能である。 In one aspect of the present invention, the above-mentioned second battery 101b corresponds to a newly installed battery and functions as an auxiliary to the first battery 101a. In other words, the second battery 101b suppresses deterioration of the first battery 101a and can extend the cycle life (also simply referred to as life) of the first battery 101a. As a result, the first battery 101a does not need to be replaced during the period until the electric vehicle 11 is scrapped. Or, the frequency of replacement of the first battery 101a can be reduced. Since the first battery 101a fixed to the vehicle chassis is configured to be difficult to replace compared to a battery pack, it can be said that the improvement of the life of the first battery 101a has a significant effect. Of course, in one aspect of the present invention, it is also possible to make the first battery 101a function as an auxiliary to the second battery 101b.
劣化を抑制したい第１のバッテリ１０１ａは、補助のための第２のバッテリ１０１ｂより、モータから離れた位置に搭載するとよい。すなわち劣化を抑制したい第１のバッテリ１０１ａは、熱源となりうるモータから離すと好ましい。 The first battery 101a, which is to be prevented from deteriorating, should be mounted farther away from the motor than the auxiliary second battery 101b. In other words, it is preferable to place the first battery 101a, which is to be prevented from deteriorating, away from the motor, which can be a heat source.
また本発明の一態様のバッテリ１０１が二以上のバッテリを有することで、上記補助の関係を満たすことができ、少なくとも第１のバッテリ１０１ａの劣化を抑制できる。当該劣化を抑制する限りにおいて、本発明において、第１のバッテリ１０１ａは車両シャーシに固定されていなくともよく、例えばバッテリパックに収容されていてもよい。すなわち、本発明の一形態において二以上のバッテリは、いずれもバッテリパックに収容されていてもよい。 Furthermore, by having two or more batteries in the battery 101 of one embodiment of the present invention, the above-mentioned auxiliary relationship can be satisfied, and deterioration of at least the first battery 101a can be suppressed. As long as the deterioration is suppressed, in the present invention, the first battery 101a does not need to be fixed to the vehicle chassis, and may be housed in, for example, a battery pack. In other words, in one embodiment of the present invention, all of the two or more batteries may be housed in a battery pack.
＜第１のバッテリ１０１ａと第２のバッテリ１０１ｂとの組み合わせ１＞
第１のバッテリ１０１ａは、第２のバッテリ１０１ｂよりも安全性の高い単電池を用いると好ましい。単電池の安全性を向上させるには、正極活物質を適宜選択するとよい。その他、電解液、負極活物質、及びセパレータ材料を適宜選択してもよい。正極活物質の場合、安全性の高い単電池を発現するものとして、リン酸鉄リチウム（ＬｉＦｅＰＯ４）、リン酸マンガンリチウム（ＬｉＭｎＰＯ４）、リン酸コバルトリチウム（ＬｉＣｏＰＯ４）、リン酸ニッケルリチウム（ＬｉＮｉＰＯ４）などの、リチウム（Ｌｉ）に加えて、鉄（Ｆｅ）、マンガン（Ｍｎ）、コバルト（Ｃｏ）またはニッケル（Ｎｉ）を含むオリビン型の結晶構造を有する複合酸化物（オリビン型の結晶構造有するリン酸化合物とも呼ぶ）が挙げられる。上述したオリビン構造を有する正極活物質は、例えば層状岩塩型の結晶構造を有する正極活物質などと比較して、充放電に伴う構造変化がきわめて少なく、結晶構造が安定である。そのため、過充電などの動作に対しても安定であり、正極活物質として用いた場合に安全性の高い単電池を実現することができる。 <Combination 1 of the first battery 101a and the second battery 101b>
The first battery 101a is preferably a cell that is safer than the second battery 101b. In order to improve the safety of the cell, the positive electrode active material may be appropriately selected. In addition, the electrolyte, the negative electrode active material, and the separator material may be appropriately selected. In the case of the positive electrode active material, a cell with high safety can be realized by a composite oxide having an olivine crystal structure (also called a phosphate compound having an olivine crystal structure) containing iron ( Fe ), manganese ( Mn ), cobalt (Co) or nickel (Ni) in addition to lithium (Li), such as lithium iron phosphate (LiFePO 4 ), lithium manganese phosphate (LiMnPO 4 ), lithium cobalt phosphate (LiCoPO 4 ), and lithium nickel phosphate (LiNiPO 4 ). The above-mentioned positive electrode active material having an olivine structure has a very small structural change due to charging and discharging, and has a stable crystal structure, as compared with, for example, a positive electrode active material having a layered rock salt type crystal structure. Therefore, it is stable even against operations such as overcharging, and when used as a positive electrode active material, a highly safe unit cell can be realized.
第２のバッテリ１０１ｂは、第１のバッテリ１０１ａより高電圧で充電が可能な単電池を用いると好ましい。高電圧充電を可能にするには、正極活物質を適宜選択するとよい。その他、電解液、負極活物質、及びセパレータ材料を適宜選択してもよい。正極活物質の場合、高電圧充電を可能にするものとして、コバルト酸リチウム（ＬＣＯとも記す）、ニッケル−コバルト−マンガン酸リチウム（ＮＣＭとも記す）、ニッケル−コバルト−アルミニウム酸リチウム（ＮＣＡとも記す）、およびニッケル−マンガン−アルミニウム酸リチウム（ＮＭＡとも記す）等の、層状岩塩型構造を有するリン酸化合物が挙げられる。層状岩塩型構造を有するリン酸化合物は遷移金属ＭとしたときのＭＯ６八面体からなる層間をリチウムイオンが二次元的に移動することができるため、サイクル特性が良好であり、高電圧充電を可能にする。特にコバルト酸リチウムは、添加元素を加えて高電圧充電での相変化を抑制することができるため、高電圧充電には好適な材料である。添加元素には、マグネシウム、アルミニウム、ニッケル、フッ素、及びチタンから選ばれた一又は複数を用いるとよい。 The second battery 101b is preferably a single cell that can be charged at a higher voltage than the first battery 101a. To enable high-voltage charging, the positive electrode active material may be appropriately selected. In addition, the electrolyte, the negative electrode active material, and the separator material may be appropriately selected. In the case of the positive electrode active material, phosphate compounds having a layered rock salt structure, such as lithium cobalt oxide (also referred to as LCO), lithium nickel-cobalt-manganese oxide (also referred to as NCM), lithium nickel-cobalt-aluminate (also referred to as NCA), and lithium nickel-manganese-aluminate (also referred to as NMA), can be cited as examples of materials that enable high-voltage charging. Phosphate compounds having a layered rock salt structure have good cycle characteristics and enable high-voltage charging because lithium ions can move two-dimensionally between layers consisting of MO 6 octahedra when the transition metal M is used. In particular, lithium cobalt oxide is a suitable material for high-voltage charging because it is possible to suppress phase changes during high-voltage charging by adding an additive element. The additive element may be one or more selected from the group consisting of magnesium, aluminum, nickel, fluorine, and titanium.
上述したとおり、二以上のバッテリの組み合わせは、正極活物質が異なるものを用いると好ましい。 As mentioned above, it is preferable to use a combination of two or more batteries with different positive electrode active materials.
正極活物質が有する添加元素について説明する。 The additive elements contained in the positive electrode active material are explained below.
＜マグネシウム＞
添加元素の一つであるマグネシウムイオンは２価で、マグネシウムイオンは層状岩塩型の結晶構造におけるコバルトサイトよりもリチウムサイトに存在する方が安定であるため、リチウムサイトに入りやすい。マグネシウムが表層部のリチウムサイトに適切な濃度で存在することで、高電圧充電においても層状岩塩型の結晶構造を保持しやすくできる。 <Magnesium>
Magnesium ions, one of the added elements, are divalent, and magnesium ions are more stable at the lithium site than at the cobalt site in the layered rock-salt crystal structure, so they tend to enter the lithium site. The presence of magnesium at an appropriate concentration at the lithium site in the surface layer makes it easier to maintain the layered rock-salt crystal structure even during high-voltage charging.
＜アルミニウム＞
添加元素の一つであるアルミニウムは層状岩塩型の結晶構造におけるコバルトサイトに存在しうる。アルミニウムは典型元素であり価数が３価から変化しないため、充放電の際もアルミニウム周辺のリチウムは移動しにくい。そのためアルミニウムとその周辺のリチウムが柱として機能し、結晶構造の変化を抑制しうる。またアルミニウムは周囲のコバルトの溶出を抑制し、連続充電耐性を向上する効果がある。 <Aluminum>
Aluminum, one of the added elements, can exist at the cobalt site in the layered rock salt crystal structure. Since aluminum is a typical element and its valence does not change from trivalent, lithium around the aluminum is difficult to move even during charging and discharging. Therefore, aluminum and the lithium around it function as pillars, which can suppress changes in the crystal structure. Aluminum also has the effect of suppressing the dissolution of surrounding cobalt and improving continuous charging resistance.
＜ニッケル＞
添加元素の一つであるニッケルは、コバルトサイトとリチウムサイトのどちらにも存在しうる。ニッケルがリチウムサイトに存在する場合、コバルトと酸素の８面体からなる層状構造のずれが抑制されうる。また充放電に伴う体積の変化が抑制される。またコバルトサイトに存在する場合、コバルトと比較して酸化還元電位が低くなるため放電容量の増加につながり好ましい。 <Nickel>
Nickel, one of the additive elements, can exist in both the cobalt site and the lithium site. When nickel exists in the lithium site, it can suppress the shift of the layered structure consisting of octahedra of cobalt and oxygen. It also suppresses the change in volume caused by charging and discharging. When nickel exists in the cobalt site, it is preferable because it leads to an increase in discharge capacity because its redox potential is lower than that of cobalt.
＜フッ素＞
添加元素の一つであるフッ素イオンは１価の陰イオンであり、正極活物質の表層部において酸素の一部がフッ素に置換されていると、リチウム脱離エネルギーが小さくなる。これは、リチウム脱離に伴うコバルトイオンの価数の変化が、フッ素を有さない場合は３価から４価、フッ素を有する場合は２価から３価となり、酸化還元電位が異なることによる。そのため正極活物質の表層部において酸素の一部がフッ素に置換されていると、フッ素近傍のリチウムイオンの脱離および挿入がスムースに起きやすいと言える。そのため二次電池に用いたときに充放電特性、電流特性等を向上させることができる。 <Fluorine>
Fluorine ions, which are one of the additive elements, are monovalent anions, and when part of the oxygen in the surface layer of the positive electrode active material is replaced by fluorine, the lithium desorption energy is reduced. This is because the valence of the cobalt ion changes with lithium desorption from trivalent to tetravalent in the absence of fluorine, and from divalent to trivalent in the presence of fluorine, resulting in different redox potentials. Therefore, when part of the oxygen in the surface layer of the positive electrode active material is replaced by fluorine, it can be said that desorption and insertion of lithium ions near the fluorine occurs more smoothly. Therefore, when used in a secondary battery, the charge/discharge characteristics, current characteristics, etc. can be improved.
＜チタン＞
添加元素の一つであるチタンの酸化物は超親水性を有することが知られている。そのため、正極活物質の表層部にチタン酸化物を有する正極活物質とすることで、極性の高い溶媒に対して濡れ性がよくなる可能性がある。 <Titanium>
Titanium oxide, one of the additive elements, is known to have superhydrophilicity, so by forming a cathode active material having titanium oxide on the surface layer thereof, it is possible that the cathode active material may have good wettability with highly polar solvents.
＜第１のバッテリ１０１ａと第２のバッテリ１０１ｂとの組み合わせ２＞
二以上のバッテリの組み合わせは、電池特性が異なるものを用いてもよい。例えば第１のバッテリ１０１ａの電池特性が、第２のバッテリ１０１ｂの電池特性と異なるとよい。電池特性に寄与するパラメータに容量、電圧などがある。そのため、第２のバッテリ１０１ｂの容量（ｍＡｈ／ｇ）を第１のバッテリ１０１ａの容量（ｍＡｈ／ｇ）より大きくするとよい。容量は活物質の重量に従うパラメータであるため、二以上のバッテリの組み合わせは上記容量を単電池の容量値と読み替えてよい。また第２のバッテリ１０１ｂの出力特性を第１のバッテリ１０１ａの出力特性より高くするとよい。二以上のバッテリの組み合わせについて出力特性をバッテリの上限電圧と読み替えてもよい。 <Combination 2 of the first battery 101a and the second battery 101b>
The combination of two or more batteries may use batteries with different battery characteristics. For example, the battery characteristics of the first battery 101a may be different from the battery characteristics of the second battery 101b. Parameters that contribute to the battery characteristics include capacity and voltage. Therefore, the capacity (mAh/g) of the second battery 101b may be made larger than the capacity (mAh/g) of the first battery 101a. Since the capacity is a parameter that depends on the weight of the active material, the above capacity may be read as the capacity value of a single battery in the combination of two or more batteries. In addition, the output characteristics of the second battery 101b may be made higher than the output characteristics of the first battery 101a. The output characteristics of the combination of two or more batteries may be read as the upper limit voltage of the battery.
＜第１のバッテリ１０１ａと第２のバッテリ１０１ｂとの組み合わせ３＞
二以上のバッテリの組み合わせは、車両に搭載される形態を異ならせてもよい。図１Ｂの車両シャーシに固定される形態と、図１Ｃのバッテリパックとの組み合わせてもよい。 <Combination 3 of the first battery 101a and the second battery 101b>
The combination of two or more batteries may be mounted on a vehicle in different ways, for example, a combination of a battery fixed to a vehicle chassis as shown in FIG. 1B and a battery pack as shown in FIG. 1C may be used.
また図１Ａに示すように、電気自動車１１の充電口１９は、普通充電用充電口１９ａを少なくとも有し、加えて急速充電用充電口１９ｂを有するとよい。 As shown in FIG. 1A, the charging port 19 of the electric vehicle 11 has at least a normal charging port 19a, and may also have a rapid charging port 19b.
次に図１Ｄを用いて、本発明の一態様のバッテリ制御システム１０等を含む電気自動車１１のブロック図を示す。電気自動車１１はＶｅｈｉｃｌｅ　Ｃｏｎｔｒｏｌ　Ｕｎｉｔ（以下ＶＣＵと記す）２１、及びＣｏｎｔｒｏｌｌｅｒ　Ａｒｅａ　Ｎｅｔｗｏｒｋ（以下ＣＡＮと記す）２５を有する。ＶＣＵ２１はアクセル信号、及び／又はブレーキ信号が入力されることがあり、車内のディスプレイを制御する機能を有する。ＣＡＮ２５はＶＣＵ２１と電気的に接続され、ＧＰＳ信号を受信することができる。ＣＡＮ２５は、バッテリ制御システム１０等と電気的に接続することができる。 Next, FIG. 1D shows a block diagram of an electric vehicle 11 including a battery control system 10 according to one embodiment of the present invention. The electric vehicle 11 has a Vehicle Control Unit (hereinafter referred to as VCU) 21 and a Controller Area Network (hereinafter referred to as CAN) 25. The VCU 21 may receive an accelerator signal and/or a brake signal, and has a function of controlling the display inside the vehicle. The CAN 25 is electrically connected to the VCU 21 and can receive GPS signals. The CAN 25 can be electrically connected to the battery control system 10, etc.
ヘッドライト２３等は補助バッテリ２４を用いて動作することができる。なお、補助バッテリ２４には二次電池（例えば、鉛電池など）を用いることができる。また、補助バッテリ２４は、動作電圧から１２Ｖバッテリと呼ばれる場合がある。 The headlights 23 and other components can be operated using an auxiliary battery 24. The auxiliary battery 24 can be a secondary battery (e.g., a lead battery). The auxiliary battery 24 is sometimes called a 12V battery because of its operating voltage.
電気自動車１１が有する普通充電用充電口１９ａは、変換器（車載充電器とも呼ぶ）１８を介して、充電制御回路１２と電気的に接続される。変換器１８はＡＣ／ＤＣ回路等の変換装置を有し、充電スタンドからの交流電流を直流電流に変換する機能を有する。普通充電時、交流電流から直流電流に変換する処理を電気自動車１１側で行う。そのため、普通充電は充電時間を要することがある。 The electric vehicle 11 has a normal charging port 19a that is electrically connected to the charging control circuit 12 via a converter (also called an on-board charger) 18. The converter 18 has a conversion device such as an AC/DC circuit, and has the function of converting alternating current from the charging station to direct current. During normal charging, the process of converting alternating current to direct current is performed on the electric vehicle 11 side. Therefore, normal charging may take a long time.
また急速充電用充電口１９ｂは、変換器１８を介さずに、充電制御回路１２と電気的に接続されるとよい。急速充電では、交流電流から直流電流に変換する処理を充電スタンド側で行う。図２には、急速充電を可能にする充電スタンド３０を例示する。充電スタンド３０は、交流電源３１と電気的に接続され、交流電流から直流電流に変換する処理のための大規模な回路を備える。当該回路には、コンバータ３３、インバータ３４、トランス回路３５及び整流回路３６等があり、これらは図２に示すように互いに電気的に接続される。トランス回路３５は、高周波絶縁トランスを適用すると好ましい。またインバータ３４からの信号がトランス回路３５へ入力し、トランス回路３５からの信号が整流回路３６へ出力される関係を機能的な接続と呼び、本明細書等において機能的な接続は電気的な接続に含ませることとする。充電スタンド３０に備えられたコネクタ３７を、急速充電用充電口１９ｂへ差し込むことで充電が可能となる。充電スタンド３０で交流電流から直流電流に変換することにより、さらに上記回路により高速に処理することが可能であるため、急速充電では充電時間を短くすることができる。直流電流を用いてバッテリを充電する場合、つまり急速充電する場合、電流に上限を設けながら充電すると安全性を高めることができる。なお、電気自動車１１は急速充電用充電口１９ｂを備えていなくともよい。 Furthermore, the charging port 19b for quick charging may be electrically connected to the charging control circuit 12 without the converter 18. In quick charging, the process of converting AC current to DC current is performed on the charging stand side. FIG. 2 illustrates a charging stand 30 that enables quick charging. The charging stand 30 is electrically connected to an AC power source 31 and has a large-scale circuit for converting AC current to DC current. The circuit includes a converter 33, an inverter 34, a transformer circuit 35, and a rectifier circuit 36, which are electrically connected to each other as shown in FIG. 2. It is preferable that a high-frequency insulating transformer is applied to the transformer circuit 35. In addition, the relationship in which a signal from the inverter 34 is input to the transformer circuit 35 and a signal from the transformer circuit 35 is output to the rectifier circuit 36 is called a functional connection, and in this specification, the functional connection is included in the electrical connection. Charging is possible by inserting a connector 37 provided on the charging stand 30 into the charging port 19b for quick charging. By converting AC current to DC current at the charging station 30, the above circuitry can process the current at high speed, shortening the charging time during rapid charging. When charging the battery using DC current, i.e., rapid charging, setting an upper limit on the current can increase safety. Note that the electric vehicle 11 does not need to be equipped with a rapid charging port 19b.
変換器１８、又は急速充電用充電口１９ｂと電気的に接続された充電制御回路１２は、バッテリ制御システム１０と電気的に接続される。別言すると、充電制御回路１２からの信号が、バッテリ制御システム１０の入力信号の一となる。バッテリ制御システム１０には他の回路からの信号が入力されてもよい。 The charge control circuit 12, which is electrically connected to the converter 18 or the quick charge port 19b, is electrically connected to the battery control system 10. In other words, a signal from the charge control circuit 12 becomes one of the input signals to the battery control system 10. Signals from other circuits may also be input to the battery control system 10.
図１Ｄに示すように、バッテリ制御システム１０は、第１のバッテリ１０１ａ、第２のバッテリ１０１ｂ、及びＢＭＳ１５０を少なくとも有する。ＢＭＳ１５０は少なくとも安全制御システムとして機能し、図３に示すようにマイコン１５０ａ、保護ＩＣ１５０ｂを有する。さらにＢＭＳ１５０を電気自動車に搭載する場合、ＢＭＳ１５０は上述したシステムを走行中に実行させる必要がある。そのため、走行距離、及び残走行距離に関する情報をＢＭＳ１５０へ随時送信すると好ましい。なおＢＭＳ１５０及びバッテリ制御システム１０の詳細は、図３及び図４等を用いて後述する。 As shown in FIG. 1D, the battery control system 10 has at least a first battery 101a, a second battery 101b, and a BMS 150. The BMS 150 functions as at least a safety control system, and has a microcomputer 150a and a protection IC 150b as shown in FIG. 3. Furthermore, when the BMS 150 is installed in an electric vehicle, the BMS 150 needs to execute the above-mentioned system while the vehicle is traveling. Therefore, it is preferable to transmit information regarding the mileage and remaining mileage to the BMS 150 at any time. Details of the BMS 150 and the battery control system 10 will be described later using FIG. 3 and FIG. 4, etc.
バッテリ制御システム１０は、モータ制御回路１４と電気的に接続される。モータ制御回路１４はインバータとも呼ばれ、駆動用モータ１５と一体化されて車両に搭載ことがある。モータ制御回路１４は、第１のバッテリ１０１ａ、及び／又は第２のバッテリ１０１ｂからの直流電流を交流電流（三相交流）に変換する機能を有する。さらにモータ制御回路１４は、アクセル操作に応じて、駆動用モータ１５を制御する機能を有する。 The battery control system 10 is electrically connected to a motor control circuit 14. The motor control circuit 14 is also called an inverter, and may be integrated with a drive motor 15 and mounted on a vehicle. The motor control circuit 14 has a function of converting DC current from the first battery 101a and/or the second battery 101b into AC current (three-phase AC). Furthermore, the motor control circuit 14 has a function of controlling the drive motor 15 in response to accelerator operation.
駆動用モータ１５はタイヤ１３と接続され、第１のバッテリ１０１ａ、及び／又は第２のバッテリ１０１ｂから放電された電力を用いてタイヤ１３を回転させることができる。別言すると、駆動用モータ１５はバッテリからの電力を回転力に変える機能を有する。駆動用モータ１５は永久磁石、又は電磁石が用いられる。駆動用モータ１５の最大電圧は３００Ｖ以上８００Ｖ以下、好ましくは４００Ｖ以上８００Ｖ以下と高電圧が好ましい。なお第１のバッテリ１０１ａ、及び／又は第２のバッテリ１０１ｂの放電レートは、タイヤ１３の回転数、つまりアクセル操作に応じて決定されることがある。 The drive motor 15 is connected to the tire 13 and can rotate the tire 13 using the power discharged from the first battery 101a and/or the second battery 101b. In other words, the drive motor 15 has the function of converting the power from the battery into rotational force. A permanent magnet or an electromagnet is used for the drive motor 15. The maximum voltage of the drive motor 15 is preferably high, 300V or more and 800V or less, and preferably 400V or more and 800V or less. The discharge rate of the first battery 101a and/or the second battery 101b may be determined according to the rotation speed of the tire 13, i.e., the accelerator operation.
図示しないが、タイヤ１３と駆動用モータ１５との間にはトランスミッション（変速機とも呼ぶ）などが配置されている。トランスミッションは駆動用モータ１５からの動力を、アクセル操作に応じてタイヤ１３へ伝える機能を有する。電気自動車１１が発進するとき、駆動用モータ１５による回転数を高める必要があるが、タイヤ１３の回転数は低い。トランスミッションは上述したような発進時の駆動用モータ１５とタイヤ１３のバランスを取る役割を果たす。モータ制御回路１４、駆動用モータ１５に加えてトランスミッションが一体化されたものを電動アクスルと呼び、電動アクスルが車両に搭載されることがある。 Although not shown, a transmission (also called a gearbox) and the like are arranged between the tires 13 and the drive motor 15. The transmission has the function of transmitting power from the drive motor 15 to the tires 13 in response to accelerator operation. When the electric vehicle 11 starts moving, the rotation speed of the drive motor 15 needs to be increased, but the rotation speed of the tires 13 is low. The transmission plays a role in balancing the drive motor 15 and the tires 13 when starting as described above. An integrated motor control circuit 14, drive motor 15, and transmission is called an electric axle, and electric axles are sometimes installed on vehicles.
次に、バッテリ制御システム１０について、図３及び図４を用いて説明する。バッテリ制御システム１０は、第１のバッテリ１０１ａ、第２のバッテリ１０１ｂ、及びＢＭＳ１５０を少なくとも有する。ＢＭＳ１５０はマイコン１５０ａ、及び保護ＩＣ１５０ｂを少なくとも有し、単電池に関する電流、電圧、及び温度等の情報が入力される。マイコン１５０ａ等を用いて、組電池に関する電流、電圧、及び温度等の情報は推定することもできる。 Next, the battery control system 10 will be described with reference to Figures 3 and 4. The battery control system 10 has at least a first battery 101a, a second battery 101b, and a BMS 150. The BMS 150 has at least a microcomputer 150a and a protection IC 150b, and receives information on the current, voltage, temperature, etc. related to the single battery. Information on the current, voltage, temperature, etc. related to the battery pack can also be estimated using the microcomputer 150a, etc.
バッテリ制御システム１０は新たな制御回路を追加することなく、マイコン１５０ａを用いることが可能である。バッテリ制御システム１０に関する演算は、マイコン１５０ａが有するＣＰＵ（Ｃｅｎｔｒａｌ　Ｐｒｏｃｅｓｓｉｎｇ　Ｕｎｉｔ）などの処理に負担をかけることがない。勿論、バッテリ制御システム１０ではマイコン１５０ａ以外の制御回路を用意して動作させてもよい。 The battery control system 10 can use the microcomputer 150a without adding a new control circuit. Calculations related to the battery control system 10 do not place a burden on the processing of the CPU (Central Processing Unit) of the microcomputer 150a. Of course, the battery control system 10 may also be operated using a control circuit other than the microcomputer 150a.
図４Ａにはマイコン１５０ａにより動作可能なソフトの例を示す。マイコン１５０ａは、電圧監視ソフト１５１、ＳＰＣ演算ソフト１５２、絶縁抵抗検知ソフト１５３、電流検知ソフト１５４、温度調整制御１５５、ＣＡＮソフト１５６、及びリレーシーケンスソフト１５７等が搭載されるとよい。上述した各ソフトは、図１ＤのＣＡＮ２５等と信号の授受が可能なように電気的に接続されている。 Figure 4A shows an example of software that can be operated by the microcomputer 150a. The microcomputer 150a may be equipped with voltage monitoring software 151, SPC calculation software 152, insulation resistance detection software 153, current detection software 154, temperature adjustment control 155, CAN software 156, and relay sequence software 157. Each of the above-mentioned software is electrically connected to the CAN 25 in Figure 1D, etc. so as to be able to send and receive signals.
図４Ｂには保護ＩＣ１５０ｂに関する回路図を例示する。図４Ｂのように保護ＩＣ１５０ｂは、第１の保護ＩＣ１５０ｂｘ（１）と、第ｎの保護ＩＣ１５０ｂｘ（ｎ）と、を有する。ただしｎは２以上の整数とする。第１の保護ＩＣ１５０ｂｘ（１）は、第１のバッテリ１０１ａが有する単電池１ａ（１）と電気的に接続されたものである。第ｎの保護ＩＣ１５０ｂｘ（ｎ）は、第１のバッテリ１０１ａが有する単電池１ａ（ｎ）と電気的に接続されたものである。このように保護ＩＣ１５０ｂは単電池に応じた数を用意するとよい。 Figure 4B shows an example of a circuit diagram for the protection IC 150b. As shown in Figure 4B, the protection IC 150b has a first protection IC 150bx(1) and an nth protection IC 150bx(n), where n is an integer equal to or greater than 2. The first protection IC 150bx(1) is electrically connected to the single cell 1a(1) of the first battery 101a. The nth protection IC 150bx(n) is electrically connected to the single cell 1a(n) of the first battery 101a. In this way, it is advisable to prepare a number of protection ICs 150b according to the number of single cells.
さらに図４Ｂでは保護ＩＣ１５０ｂは、さらに第１の保護ＩＣ１５０ｂｙ（１）、第ｍの保護ＩＣ１５０ｂｙ（ｍ）を有する。ただしｍは２以上の整数とする。第１の保護ＩＣ１５０ｂｙ（１）は第２のバッテリ１０１ｂが有する単電池１ｂ（１）と電気的に接続されたものである。第ｍの保護ＩＣ１５０ｂｙ（ｍ）は第２のバッテリ１０１ｂが有する単電池１ｂ（ｍ）と電気的に接続されたものである。このように保護ＩＣ１５０ｂは単電池に応じた数を用意するとよい。なお、ｍはｎと等しい整数、ｎ以下の整数、ｎ以上の整数を取ることができる。 Furthermore, in FIG. 4B, the protection IC 150b further includes a first protection IC 150by(1) and an mth protection IC 150by(m), where m is an integer of 2 or more. The first protection IC 150by(1) is electrically connected to the single cell 1b(1) of the second battery 101b. The mth protection IC 150by(m) is electrically connected to the single cell 1b(m) of the second battery 101b. In this way, it is advisable to prepare a number of protection ICs 150b according to the number of single cells. Note that m can be an integer equal to n, an integer less than n, or an integer greater than n.
上記保護ＩＣ１５０ｂにより、各ソフトからの演算結果に基づき各単電池を制御することが可能となる。 The protection IC 150b makes it possible to control each cell based on the calculation results from each software.
さらに、バッテリ制御システム１０は、第１の回路１０６ａ、第２の回路１０６ｂ、第１のＤＣ／ＤＣ回路（ＤＣ／ＤＣコンバータが含まれる）１０７ａ、第２のＤＣ／ＤＣ回路（ＤＣ／ＤＣコンバータが含まれる）１０７ｂ、第１のセンサ回路１０２ａ、第２のセンサ回路１０２ｂを有する。上述したすべての回路は、ＢＭＳ１５０と信号の授受が可能となるように、図３に示すように互いに電気的に接続されている。ＢＭＳ１５０と第１のセンサ回路１０２ａ、第２のセンサ回路１０２ｂとの電気的な接続は、バス配線を用いるとよい。 Furthermore, the battery control system 10 has a first circuit 106a, a second circuit 106b, a first DC/DC circuit (including a DC/DC converter) 107a, a second DC/DC circuit (including a DC/DC converter) 107b, a first sensor circuit 102a, and a second sensor circuit 102b. All of the above-mentioned circuits are electrically connected to each other as shown in FIG. 3 so as to enable transmission and reception of signals with the BMS 150. The electrical connection between the BMS 150 and the first sensor circuit 102a and the second sensor circuit 102b may be made using bus wiring.
第１のＤＣ／ＤＣ回路１０７ａ、第２のＤＣ／ＤＣ回路１０７ｂを制御する信号はバッテリ制御システム１０が有する制御回路を用いて生成することができるが、上述したようにＢＭＳ１５０が有するマイコン１５０ａを用いて、第１のＤＣ／ＤＣ回路１０７ａ、第２のＤＣ／ＤＣ回路１０７ｂからの出力を決定すると好ましい。具体的にはＢＭＳ１５０からの出力信号により、第１のＤＣ／ＤＣ回路１０７ａ、第２のＤＣ／ＤＣ回路１０７ｂがそれぞれ有するスイッチを制御することができる。スイッチの動作に応じて、第１のＤＣ／ＤＣ回路１０７ａ、第２のＤＣ／ＤＣ回路１０７ｂはそれぞれ入力電圧よりも出力電圧を高くし、または低くすることができる。 Signals for controlling the first DC/DC circuit 107a and the second DC/DC circuit 107b can be generated using a control circuit in the battery control system 10, but as described above, it is preferable to use the microcomputer 150a in the BMS 150 to determine the outputs from the first DC/DC circuit 107a and the second DC/DC circuit 107b. Specifically, the output signal from the BMS 150 can control the switches in the first DC/DC circuit 107a and the second DC/DC circuit 107b. Depending on the operation of the switch, the first DC/DC circuit 107a and the second DC/DC circuit 107b can each make the output voltage higher or lower than the input voltage.
またバッテリ制御システム１０の出力は、モータ制御回路１４と電気的に接続されるが、これらの間にダイオードを配置してもよい。ダイオードにより、第１のＤＣ／ＤＣ回路１０７ａからの出力電位が、第２のＤＣ／ＤＣ回路１０７ｂからの出力電位より高い場合、又は低い場合、第１のバッテリ１０１ａからの電力が第２のバッテリ１０１ｂへ供給されてしまうこと、第２のバッテリ１０１ｂからの電力が第１のバッテリ１０１ａへ供給されてしまうことを防止できる。図３では、第１のＤＣ／ＤＣ回路１０７ａと、出力との間に、第１のダイオード１０８ａを電気的に接続させ、第２のＤＣ／ＤＣ回路１０７ｂと、出力との間に、第２のダイオード１０８ｂを電気的に接続させている。 The output of the battery control system 10 is electrically connected to the motor control circuit 14, and a diode may be placed between them. When the output potential from the first DC/DC circuit 107a is higher or lower than the output potential from the second DC/DC circuit 107b, the diode can prevent the power from the first battery 101a from being supplied to the second battery 101b and the power from the second battery 101b from being supplied to the first battery 101a. In FIG. 3, a first diode 108a is electrically connected between the first DC/DC circuit 107a and the output, and a second diode 108b is electrically connected between the second DC/DC circuit 107b and the output.
さらに第１のセンサ回路１０２ａ、第２のセンサ回路１０２ｂはそれぞれ、電圧センサ及び／又は電流センサを有することができる。具体的には第１のセンサ回路１０２ａは第１の電圧センサ１０３ａ、第１の電流センサ１０４ａを有し、第２のセンサ回路１０２ｂは第２の電圧センサ１０３ｂ、第２の電流センサ１０４ｂを有する。第１の電圧センサ１０３ａは第１のバッテリ１０１ａの電圧を測定する機能を有し、これが可能となるように第１の電圧センサ１０３ａと第１のバッテリ１０１ａとが電気的に接続されている。第２の電圧センサ１０３ｂは第２のバッテリ１０１ｂの電圧を測定する機能を有し、これが可能となるように第２の電圧センサ１０３ｂと第２のバッテリ１０１ｂとが電気的に接続されている。第１の電流センサ１０４ａは第１のバッテリ１０１ａの電流を測定する機能を有し、これが可能となるように第１の電流センサ１０４ａと第１のバッテリ１０１ａとが電気的に接続されている。第２の電流センサ１０４ｂは第２のバッテリ１０１ｂの電流を測定する機能を有し、これが可能となるように第２の電流センサ１０４ｂと第２のバッテリ１０１ｂとが電気的に接続されている。測定される電流値はバッテリの充電時、及び／又は放電時を対象とし、測定される電圧値もバッテリの充電時、及び／又は放電時を対象とする。 Furthermore, the first sensor circuit 102a and the second sensor circuit 102b may each have a voltage sensor and/or a current sensor. Specifically, the first sensor circuit 102a has a first voltage sensor 103a and a first current sensor 104a, and the second sensor circuit 102b has a second voltage sensor 103b and a second current sensor 104b. The first voltage sensor 103a has a function of measuring the voltage of the first battery 101a, and the first voltage sensor 103a and the first battery 101a are electrically connected to each other so that this is possible. The second voltage sensor 103b has a function of measuring the voltage of the second battery 101b, and the second voltage sensor 103b and the second battery 101b are electrically connected to each other so that this is possible. The first current sensor 104a has a function of measuring the current of the first battery 101a, and the first current sensor 104a and the first battery 101a are electrically connected to enable this. The second current sensor 104b has a function of measuring the current of the second battery 101b, and the second current sensor 104b and the second battery 101b are electrically connected to enable this. The measured current value is for when the battery is being charged and/or discharged, and the measured voltage value is for when the battery is being charged and/or discharged.
第１のバッテリ１０１ａが有する単電池ごとに第１の電圧センサ１０３ａが電気的に接続されることによって、単電池ごとの電圧を測定することができる。 The first voltage sensor 103a is electrically connected to each cell in the first battery 101a, allowing the voltage of each cell to be measured.
第２のバッテリ１０１ｂが有する単電池ごとに第２の電圧センサ１０３ｂが電気的に接続されることによって、単電池ごとの電圧を測定することができる。 The second voltage sensor 103b is electrically connected to each cell in the second battery 101b, allowing the voltage of each cell to be measured.
さらにバッテリ制御システム１０はカウンタ回路等を付加することで時間の計測が可能となる。当該時間と電流値を積算して、バッテリの容量値を算出することも可能である。さらに第１のセンサ回路１０２ａ、第２のセンサ回路１０２ｂはそれぞれ、クーロンカウンタを有してもよい。クーロンカウンタにより電流値、及び電圧値以外に、第１のバッテリ１０１ａ、及び／又は第２のバッテリ１０１ｂの積算容量を測定することが可能になる。 Furthermore, the battery control system 10 can measure time by adding a counter circuit or the like. It is also possible to calculate the capacity value of the battery by integrating the time and the current value. Furthermore, the first sensor circuit 102a and the second sensor circuit 102b may each have a coulomb counter. The coulomb counter makes it possible to measure the integrated capacity of the first battery 101a and/or the second battery 101b in addition to the current value and voltage value.
ＢＭＳ１５０が有するマイコン１５０ａは、第１のセンサ回路１０２ａ、及び第２のセンサ回路１０２ｂより、電流値、電圧値、又は容量値（積算容量を含む）等に関するデータを受け取り、単電池の劣化を推定することが可能である。劣化の推定には、ｄＱ／ｄｖに基づく計算を実行するとより好ましい。このようなマイコン１５０ａは、バッテリの劣化等に応じて、第１のＤＣ／ＤＣ回路１０７ａ、第２のＤＣ／ＤＣ回路１０７ｂを制御することができる。 The microcomputer 150a of the BMS 150 receives data on current values, voltage values, capacity values (including integrated capacity), etc. from the first sensor circuit 102a and the second sensor circuit 102b, and is able to estimate the deterioration of the single battery. It is more preferable to perform a calculation based on dQ/dv to estimate the deterioration. Such a microcomputer 150a can control the first DC/DC circuit 107a and the second DC/DC circuit 107b in response to the deterioration of the battery, etc.
＜回路１０６の具体例＞
バッテリ制御システム１０は、さらに第１の回路１０６ａ及び第２の回路１０６ｂを有することによって、劣化抑制を可能にしうる。第１の回路１０６ａ及び第２の回路１０６ｂの回路構成等について図５を用いて説明する。なお第２の回路１０６ｂは第１の回路１０６ａと同様な回路構成を有するため、第２の回路１０６ｂの説明を簡略化することがある。 <Specific example of circuit 106>
The battery control system 10 can suppress deterioration by further including a first circuit 106a and a second circuit 106b. The circuit configurations of the first circuit 106a and the second circuit 106b will be described with reference to Fig. 5. Note that since the second circuit 106b has a similar circuit configuration to the first circuit 106a, the description of the second circuit 106b may be simplified.
第１の回路１０６ａ及び第２の回路１０６ｂへの入力信号の伝達を制御するスイッチ（以下スイッチＳＷと記す）１１を有する。第１の回路１０６ａはトランス２２ａ、及びスイッチＳＷを有する。スイッチＳＷは少なくとも二以上有し、具体的にはスイッチＳＷ２６ａ、及びスイッチＳＷ２５ａを有する。トランス２２ａには例えば絶縁トランスを用いる。トランス２２ａの一方をトランス２２ａの一次側回路と記すことがあり、他方をトランス２２ａの二次側回路と記すことがある。一次側回路にはコイルＷａ１があり、当該コイルＷａ１の一方の端部はスイッチＳＷ１２と電気的に接続され、他方はスイッチＳＷ２５ａと電気的に接続されている。またスイッチＳＷ１２は、第１のバッテリ１０１ａと電気的に接続されている。 The first circuit 106a has a switch (hereinafter referred to as switch SW) 11 that controls the transmission of input signals to the first circuit 106a and the second circuit 106b. The first circuit 106a has a transformer 22a and a switch SW. The first circuit 106a has at least two switches SW, specifically, a switch SW26a and a switch SW25a. For example, an insulating transformer is used for the transformer 22a. One side of the transformer 22a may be referred to as the primary side circuit of the transformer 22a, and the other side may be referred to as the secondary side circuit of the transformer 22a. The primary side circuit has a coil Wa1, one end of which is electrically connected to the switch SW12, and the other end is electrically connected to the switch SW25a. The switch SW12 is also electrically connected to the first battery 101a.
またトランス２２ａの二次側回路も一次側回路と同様に、コイルＷａ２、及びスイッチＳＷ２６ａを有し、当該コイルＷａ２の一方の端部はスイッチＳＷ１１と電気的に接続され、他方はスイッチＳＷ２６ａと電気的に接続されている。 Like the primary circuit, the secondary circuit of the transformer 22a also has a coil Wa2 and a switch SW26a, with one end of the coil Wa2 electrically connected to the switch SW11 and the other end electrically connected to the switch SW26a.
トランス２２ａの一方のコイル、例えばコイルＷａ１に電流をながすと、そのコイルから発生する磁場により、他方のコイル、例えばコイルＷａ２に誘導起電力が発生する。この現象を相互誘導と呼ぶことがある。これにより他方のコイル、例えばコイルＷａ２に電圧が誘導されて、コイルＷａ２に電流が流れる。本実施の形態ではコイルＷａ１の巻き数はコイルＷａ２の巻き数と同じにするが、巻き数は異なってもよい。 When a current is passed through one coil of the transformer 22a, for example coil Wa1, the magnetic field generated from that coil generates an induced electromotive force in the other coil, for example coil Wa2. This phenomenon is sometimes called mutual induction. As a result, a voltage is induced in the other coil, for example coil Wa2, and a current flows through coil Wa2. In this embodiment, the number of turns in coil Wa1 is the same as the number of turns in coil Wa2, but the numbers of turns may be different.
第１の回路１０６ａにおいてスイッチＳＷ２５ａ及びスイッチＳＷ２６ａにはＭＯＳトランジスタ等のスイッチング素子を用いるとよい。また整流するために、スイッチＳＷ２５ａには抵抗素子が電気的に接続されていてもよい。同様に、スイッチＳＷ２６ａには抵抗素子が電気的に接続されていてもよい。スイッチＳＷ２５ａ及びスイッチＳＷ２６ａのオン及びオフにより、上記誘導起電力による電流が流れるタイミングを制御できる。 In the first circuit 106a, it is preferable to use switching elements such as MOS transistors for the switches SW25a and SW26a. In addition, a resistive element may be electrically connected to the switch SW25a in order to rectify. Similarly, a resistive element may be electrically connected to the switch SW26a. The timing at which the current caused by the induced electromotive force flows can be controlled by turning the switches SW25a and SW26a on and off.
第２の回路１０６ｂは、上記第１の回路１０６ａと同様の構成を有する。ただし、第２の回路１０６ｂではコイルＷｂ１の一方の端部はスイッチＳＷ１３と電気的に接続されている。またスイッチＳＷ１３は、第２のバッテリ１０１ｂと電気的に接続されている。 The second circuit 106b has a configuration similar to that of the first circuit 106a. However, in the second circuit 106b, one end of the coil Wb1 is electrically connected to the switch SW13. The switch SW13 is also electrically connected to the second battery 101b.
＜充電時＞
各バッテリを充電するとき、スイッチＳＷ１１をオンにして、第１の回路１０６ａ、及び／又は第２の回路１０６ｂをフライバックコンバータ又はフォワードコンバータとして用いる。具体的には、第１のバッテリ１０１ａを充電する場合、スイッチＳＷ１１をオンにして、第１の回路１０６ａをフライバックコンバータ又はフォワードコンバータとして用いればよい。また、第２のバッテリ１０１ｂを充電する場合、スイッチＳＷ１１をオンとして、第２の回路１０６ｂをフライバックコンバータ又はフォワードコンバータとして用いればよい。第１の回路１０６ａと電気的に接続されたスイッチＳＷ１２を制御する、又は第２の回路１０６ｂと電気的に接続されたスイッチＳＷ１３を制御することにより、第１のバッテリ１０１ａのみを充電する期間Ａと、第２のバッテリ１０１ｂのみを充電する期間Ｂとを設けることができる。この場合、期間Ａは期間Ｂより先が好ましい。なお、第１のバッテリ１０１ａ、及び第２のバッテリ１０１ｂは同時に充電してもよい。 <When charging>
When each battery is charged, the switch SW11 is turned on to use the first circuit 106a and/or the second circuit 106b as a flyback converter or a forward converter. Specifically, when the first battery 101a is charged, the switch SW11 is turned on to use the first circuit 106a as a flyback converter or a forward converter. When the second battery 101b is charged, the switch SW11 is turned on to use the second circuit 106b as a flyback converter or a forward converter. By controlling the switch SW12 electrically connected to the first circuit 106a or the switch SW13 electrically connected to the second circuit 106b, a period A in which only the first battery 101a is charged and a period B in which only the second battery 101b is charged can be provided. In this case, the period A is preferably before the period B. The first battery 101a and the second battery 101b may be charged simultaneously.
ここで第１の回路１０６ａをフライバックコンバータとして用いる場合を説明する。スイッチＳＷ２６ａがオン、スイッチＳＷ２５ａがオフとなるように制御し、スイッチＳＷ１１を介して、コイルＷａ２に電流を流す。すると、発生する磁束によりコイルＷａ２が巻かれた鉄心（コアとも記す）が磁化される。コアが磁化されることをエネルギーの蓄積と記すことがあり、スイッチＳＷ２６ａをオンとしているときにコアにエネルギーを蓄えることができる。その後、スイッチＳＷ２６ａがオフ、スイッチＳＷ２５ａがオンとなるように制御すると、コイルＷａ１に電流が流れ、コアに蓄積されたエネルギーが開放される。このとき、スイッチＳＷ１２を介して第１のバッテリ１０１ａを充電することができる。なおコイルＷａ１の巻き数はコイルＷａ２の巻き数と異なっていてもよい。巻き数を異ならせることで、第１の回路１０６ａの入力電圧と出力電圧とを異ならせることも可能となる。またエネルギー損失を少なくするために、コアにはケイ素鋼の積層体を用いるとよい。 Here, a case where the first circuit 106a is used as a flyback converter will be described. The switch SW26a is controlled to be on and the switch SW25a is controlled to be off, and a current is passed through the coil Wa2 via the switch SW11. Then, the generated magnetic flux magnetizes the iron core (also referred to as the core) around which the coil Wa2 is wound. The magnetization of the core is sometimes referred to as the accumulation of energy, and energy can be stored in the core when the switch SW26a is turned on. After that, when the switch SW26a is controlled to be off and the switch SW25a is controlled to be on, a current flows through the coil Wa1, and the energy accumulated in the core is released. At this time, the first battery 101a can be charged via the switch SW12. The number of turns of the coil Wa1 may be different from the number of turns of the coil Wa2. By making the number of turns different, it is also possible to make the input voltage and output voltage of the first circuit 106a different. Also, to reduce energy loss, it is a good idea to use a silicon steel laminate for the core.
第２のバッテリ１０１ｂを充電する場合も、上記第１のバッテリ１０１ａを充電する場合と同様である。 The process for charging the second battery 101b is similar to that for charging the first battery 101a.
フライバックコンバータを用いて説明したが、第１の回路１０６ａはフォワードコンバータとして用いてもよい。 Although a flyback converter has been used in the description, the first circuit 106a may also be used as a forward converter.
＜転送時＞
第１の回路１０６ａ、及び第２の回路１０６ｂを有するバッテリ制御システム１０は、第１のバッテリ１０１ａ及び第２のバッテリ１０１ｂの一方の電力を、他方に転送することが可能になる。第２のバッテリ１０１ｂの電力を第１のバッテリ１０１ａへ転送する場合について図６を用いて説明する。図６は図５に示した回路構成に電流の向きを矢印（Ｘａ、Ｙａ、Ｘｂ及びＹｂ）で添えたものである。 <When transferring>
The battery control system 10 having the first circuit 106a and the second circuit 106b is capable of transferring the power of one of the first battery 101a and the second battery 101b to the other. The case where the power of the second battery 101b is transferred to the first battery 101a will be described with reference to Fig. 6. Fig. 6 shows the circuit configuration shown in Fig. 5 with arrows (Xa, Ya, Xb, and Yb) indicating the direction of current.
まずスイッチＳＷ２５ｂ及びスイッチＳＷ１３をオンとなるように制御して、第２のバッテリ１０１ｂから転送分の容量を取り出す。図６では、トランス２２ｂのコイルＷｂ１に流れる第２のバッテリ１０１ｂからの電流に矢印Ｙｂを添える。当該矢印Ｙｂのように流れる電流をＩ（ｄｉｓｃｈａｒｇｅ）と記すことがある。第２のバッテリ１０１ｂから転送分の容量は、第１のバッテリ１０１ａの劣化に応じて決めることができる。また当該転送分の容量は、第１のバッテリ１０１ａのＳＯＣに応じて決めることもできる。 First, switches SW25b and SW13 are controlled to be turned on, and the capacity to be transferred is extracted from the second battery 101b. In FIG. 6, an arrow Yb is added to the current from the second battery 101b flowing through coil Wb1 of transformer 22b. The current flowing as indicated by the arrow Yb is sometimes referred to as I (discharge). The capacity to be transferred from the second battery 101b can be determined according to the deterioration of the first battery 101a. The capacity to be transferred can also be determined according to the SOC of the first battery 101a.
スイッチＳＷ１１がオフ、スイッチＳＷ２５ｂがオフ、スイッチＳＷ２６ｂがオンとなるように制御すると、当該Ｉ（ｄｉｓｃｈａｒｇｅ）に対応した電流が、コイルＷｂ２に生じる。図６では、トランス２２ｂのコイルＷｂ２に流れる電流に矢印Ｘｂを添え、当該矢印Ｘｂのように流れる電流をＩ（ｒｅｔｕｒｎ）と記すことがあり、電荷のリターンとも呼ぶ。 When switch SW11 is controlled to be off, switch SW25b to be off, and switch SW26b to be on, a current corresponding to I (discharge) is generated in coil Wb2. In FIG. 6, an arrow Xb is added to the current flowing through coil Wb2 of transformer 22b, and the current flowing as indicated by the arrow Xb is sometimes written as I (return), also called the return of charge.
このときスイッチＳＷ２６ａがオンしているため、第１の回路１０６ａのトランス２２ａのコイルＷａ２には、Ｉ（ｒｅｔｕｒｎ）に対応した電流が流れる。図６では、コイルＷａ２に流れる電流に矢印Ｘａを添え、当該矢印Ｘａのように流れる電流をＩ（ｓｕｐｐｌｙ）と記すことがあり、電荷の供給とも呼ぶ。矢印Ｘａで示した電流は、矢印Ｘｂで示した電流と同じ値となる。ただし上記電流には、部材によるわずかな損失が生じることもある。 At this time, because the switch SW26a is on, a current corresponding to I(return) flows through the coil Wa2 of the transformer 22a of the first circuit 106a. In FIG. 6, the current flowing through the coil Wa2 is indicated by an arrow Xa, and the current flowing as indicated by the arrow Xa is sometimes referred to as I(supply), also known as the supply of charge. The current indicated by the arrow Xa has the same value as the current indicated by the arrow Xb. However, slight losses may occur in the above current due to components.
その後スイッチＳＷ２６ａがオフ、スイッチＳＷ２５ａがオンとなるように制御すると、当該Ｉ（ｓｕｐｐｌｙ）に対応した電流が、トランス２２ａのコイルＷａ１が流れる。図６では、コイルＷａ１に流れる電流に矢印Ｙａを添え、当該矢印Ｙａのように流れる電流をＩ（ｃｈａｒｇｅ）と記すことがある。 After that, when the switch SW26a is controlled to be turned off and the switch SW25a is controlled to be turned on, a current corresponding to the I(supply) flows through the coil Wa1 of the transformer 22a. In FIG. 6, the current flowing through the coil Wa1 is indicated by an arrow Ya, and the current flowing as indicated by the arrow Ya is sometimes referred to as I(charge).
スイッチＳＷ１２がオンであれば、当該Ｉ（ｃｈａｒｇｅ）は第１のバッテリ１０１ａを充電するために使われる。このようにして、第２のバッテリ１０１ｂから第１のバッテリ１０１ａへ電力が転送される。 When switch SW12 is on, I(charge) is used to charge the first battery 101a. In this way, power is transferred from the second battery 101b to the first battery 101a.
第２のバッテリ１０１ｂの電力を第１のバッテリ１０１ａへ転送する場合を説明したが、第１のバッテリ１０１ａの電力を第２のバッテリ１０１ｂへ転送することも可能であり、上記説明と電流の流れ等が逆向きとなる。 Although the case where the power of the second battery 101b is transferred to the first battery 101a has been described, it is also possible to transfer the power of the first battery 101a to the second battery 101b, in which case the current flow etc. will be in the opposite direction to that described above.
第１の回路１０６ａ、及び第２の回路１０６ｂにより各バッテリの充電に加えて転送が可能となる。第１のバッテリ１０１ａの電力を第２のバッテリ１０１ｂへ転送することにより、第１のバッテリ１０１ａの使用頻度を減らすことができ第１のバッテリ１０１ａの劣化を抑制することができ、第１のバッテリ１０１ａの寿命を向上させることができる。第１のバッテリ１０１ａが車両シャーシに固定される場合、交換の頻度を少なくすることが可能である。 The first circuit 106a and the second circuit 106b enable the charging and transfer of power to each battery. By transferring the power of the first battery 101a to the second battery 101b, the frequency of use of the first battery 101a can be reduced, deterioration of the first battery 101a can be suppressed, and the lifespan of the first battery 101a can be improved. If the first battery 101a is fixed to the vehicle chassis, it is possible to reduce the frequency of replacement.
上述したバッテリ制御システム１０を用いると、次のような特徴を備えた電気自動車１１となる。 Using the above-described battery control system 10 results in an electric vehicle 11 with the following features:
＜バッテリ制御システムの特徴１＞
上述したバッテリ制御システム１０を用いると、電気自動車１１の走行開始期間Ｘと、電気自動車１１の走行時間が十分になった期間Ｙとで、主出力を担うバッテリを選択することができる。適切な選択によれば、第１のバッテリ１０１ａの劣化が抑制される。例えば、走行開始期間Ｘに、第１のバッテリ１０１ａ及び第２のバッテリ１０１ｂからの出力を利用した場合、主出力を担うバッテリを第２のバッテリ１０１ｂと選択する。 <Characteristic 1 of the Battery Control System>
By using the battery control system 10 described above, it is possible to select a battery that will provide the main output during a period X when the electric vehicle 11 starts to travel and during a period Y when the electric vehicle 11 has had sufficient travel time. Appropriate selection can suppress deterioration of the first battery 101a. For example, when outputs from the first battery 101a and the second battery 101b are utilized during the period X when the electric vehicle 11 starts to travel, the second battery 101b is selected as the battery that will provide the main output.
走行開始期間Ｘは、高い出力電力が要求されるため、出力を担うバッテリを第２のバッテリ１０１ｂと選択することで、第１のバッテリ１０１ａの負担を軽減することができ、第１のバッテリ１０１ａの劣化を抑制することができる。勿論、第１のバッテリ１０１ａの劣化がない状態であれば、走行開始期間Ｘに第１のバッテリ１０１ａからの出力を加えることも可能である。 Since high output power is required during the driving start period X, by selecting the second battery 101b as the battery that will provide the output, the burden on the first battery 101a can be reduced and deterioration of the first battery 101a can be suppressed. Of course, if there is no deterioration of the first battery 101a, it is also possible to add output from the first battery 101a during the driving start period X.
さらに第２のバッテリ１０１ｂが有する単電池の正極活物質にＬＣＯを用いると、重量又は体積当たりの出力密度の高いバッテリとすることができるため、走行開始期間Ｘに第２のバッテリ１０１ｂを主出力を担うバッテリとすることで、バッテリ１０１の能力を高めることが可能である。 Furthermore, if LCO is used as the positive electrode active material of the single cell of the second battery 101b, the battery can have a high output density per weight or volume. Therefore, by making the second battery 101b the battery that is responsible for the main output during the driving start period X, it is possible to increase the capacity of the battery 101.
次に、電気自動車１１の走行時間が十分になった期間Ｙは、主出力を担うバッテリを第２のバッテリ１０１ｂから、第１のバッテリ１０１ａからへ切り替えるとよい。走行時間が十分になった期間Ｙは、例えばタイヤの回転数が一定になった期間が含まれる。 Next, during period Y when the electric vehicle 11 has sufficient running time, the battery responsible for the main output may be switched from the second battery 101b to the first battery 101a. Period Y when the running time is sufficient includes, for example, a period when the tire rotation speed becomes constant.
上記期間Ｘ、又は期間Ｙであるかは、時間に基づき判断してもよい。またはＶＣＵ２１からのアクセル信号及び／又はブレーキ信号に基づき、上記期間Ｘ、又は期間Ｙであるかを判断することも可能である。 Whether it is the above-mentioned period X or period Y may be determined based on time. Alternatively, it is also possible to determine whether it is the above-mentioned period X or period Y based on an accelerator signal and/or a brake signal from the VCU 21.
上述したように期間を判断したのち、さらに、ＢＭＳ１５０が第１のバッテリ１０１ａ及び第２のバッテリ１０１ｂのＳＯＣ、劣化状態、及びこれらの推定値を加えて、主出力のバッテリを決定することができると最もよい。主出力のバッテリを決定した後は、ＢＭＳ１５０からの信号により、第１のＤＣ／ＤＣ回路１０７ａ、及び第２のＤＣ／ＤＣ回路１０７ｂを制御することで、主出力のバッテリを決定することができる。 After determining the period as described above, it is best if the BMS 150 can further determine the main output battery by adding the SOC, deterioration state, and estimated values of the first battery 101a and the second battery 101b. After the main output battery is determined, the first DC/DC circuit 107a and the second DC/DC circuit 107b can be controlled by a signal from the BMS 150 to determine the main output battery.
＜バッテリ制御システムの特徴２＞
上述したバッテリ制御システム１０を用いると、第１のバッテリ１０１ａの充放電レートを一定にすることができる。例えば急速充電など高い充電レートに曝され、さらに頻繁にレートが変動すると劣化しやすいが、充電レートが一定になるように制御することで、第１のバッテリ１０１ａの劣化が抑制される。具体的には急速充電など高い充電レートに曝され、さらに頻繁にレートが変動するような場合では、第２のバッテリ１０１ｂを選択して充電するとよい。 <Characteristic 2 of Battery Control System>
By using the above-described battery control system 10, the charge/discharge rate of the first battery 101a can be made constant. For example, the first battery 101a is prone to deterioration when exposed to a high charge rate such as rapid charging and the rate fluctuates frequently, but by controlling the charge rate to be constant, deterioration of the first battery 101a can be suppressed. Specifically, in a case where the first battery 101a is exposed to a high charge rate such as rapid charging and the rate fluctuates frequently, it is advisable to select and charge the second battery 101b.
急速充電など高い充電レートに曝され、さらに頻繁にレートが変動するかは、時間に基づき判断してもよい。または充電制御回路１２からの信号に基づき急速充電など高い充電レートに曝され、さらに頻繁にレートが変動するかを判断することも可能である。 Whether the rate fluctuates more frequently due to exposure to a high charging rate such as rapid charging may be determined based on time. Alternatively, it is also possible to determine whether the rate fluctuates more frequently due to exposure to a high charging rate such as rapid charging based on a signal from the charging control circuit 12.
上述したように判断したのち、さらに、ＢＭＳ１５０が第１のバッテリ１０１ａ及び第２のバッテリ１０１ｂのＳＯＣ、劣化状態、及びこれらの推定値に加えて、第１のバッテリ１０１ａ又は第２のバッテリ１０１ｂの充放電レートなどを決定することも可能である。 After making the above-mentioned judgment, the BMS 150 can further determine the SOC, degradation state, and estimated values of the first battery 101a and the second battery 101b, as well as the charge/discharge rate of the first battery 101a or the second battery 101b.
＜バッテリ制御システムの特徴３＞
上述したバッテリ制御システム１０を用いると、回生充電の際に充電するバッテリを決めておくことができる。回生充電とは、減速時又は下り坂走行時等に、駆動用モータ１５を発電機として、バッテリ１０１に充電することである。回生充電で充電すると、バッテリが劣化しやすいため、回生充電では、第１のバッテリ１０１ａを充電する割合より、第２のバッテリ１０１ｂを充電する割合を増やす、さらには回生充電の際は、第２のバッテリ１０１ｂのみを充電することで、第１のバッテリ１０１ａの劣化を抑制することができる。 <Characteristic 3 of the Battery Control System>
By using the above-described battery control system 10, it is possible to determine the battery to be charged during regenerative charging. Regenerative charging refers to charging the battery 101 by using the drive motor 15 as a generator during deceleration, downhill driving, or the like. Since regenerative charging is likely to cause deterioration of the battery, in regenerative charging, the rate at which the second battery 101b is charged is increased compared to the rate at which the first battery 101a is charged, and further, during regenerative charging, only the second battery 101b is charged, thereby suppressing deterioration of the first battery 101a.
回生充電するかは、ＶＣＵ２１からのアクセル信号及び／又はブレーキ信号に基づき判断することができる。上記判断したのち、さらに、ＢＭＳ１５０が第１のバッテリ１０１ａ及び第２のバッテリ１０１ｂのＳＯＣ、劣化状態、及びこれらの推定値を加えて、回生充電時のバッテリを決定することも可能である。 Whether to perform regenerative charging can be determined based on the accelerator signal and/or brake signal from the VCU 21. After making the above determination, the BMS 150 can also determine the battery to be used for regenerative charging by adding the SOC, deterioration state, and estimated values of the first battery 101a and the second battery 101b.
＜バッテリ制御システムの特徴４＞
上述したバッテリ制御システム１０を用いると、カレンダー劣化を抑制することができる。カレンダー劣化とは、バッテリ劣化の一つであり、充放電サイクルに曝されずに生じる劣化、つまりバッテリを使用しない状況でも生じる劣化のことを指す。バッテリのＳＯＣが高い状態で、カレンダー劣化が進行しやすいと言われているため、第１のバッテリ１０１ａのＳＯＣを１００％未満、好ましくは９０％以下、さらに好ましくは８０％以下となるように、第２のバッテリ１０１ｂへ電力を転送することで、第１のバッテリ１０１ａの劣化を抑制することができる。 <Characteristic 4 of Battery Control System>
By using the above-described battery control system 10, calendar deterioration can be suppressed. Calendar deterioration is one type of battery deterioration, and refers to deterioration that occurs without exposure to charge/discharge cycles, that is, deterioration that occurs even when the battery is not used. It is said that calendar deterioration is likely to progress when the battery's SOC is high, so deterioration of the first battery 101a can be suppressed by transferring power to the second battery 101b so that the SOC of the first battery 101a is less than 100%, preferably 90% or less, and more preferably 80% or less.
カレンダー劣化が生じうる状況かは、時間に基づき判断してもよい。上記判断したのち、さらに、ＢＭＳ１５０が第１のバッテリ１０１ａ及び第２のバッテリ１０１ｂのＳＯＣ、劣化状態、及びこれらの推定値に加えて、各バッテリから転送する電力などを決定すると好ましい。 Whether or not a situation in which calendar degradation may occur may be determined based on time. After making the above determination, it is preferable for the BMS 150 to further determine the SOC, degradation state, and estimated values of the first battery 101a and the second battery 101b, as well as the power to be transferred from each battery.
＜ＢＭＳ１５０＞
上述したバッテリ制御システムの特徴１乃至特徴４において、ＢＭＳ１５０はマイコン１５０ａ等を有するため、例えばセルバランスを調整する以外に、単電池の状態を把握して、劣化を推定することができる。劣化の推定には、内部抵抗などを用いることができるが、次のようなデータを用いると推定精度を向上させることができる。 <BMS150>
In the above-described battery control system features 1 to 4, the BMS 150 includes the microcomputer 150a and the like, and therefore, in addition to adjusting the cell balance, for example, it is possible to grasp the state of the single battery and estimate deterioration. While internal resistance and the like can be used to estimate deterioration, the estimation accuracy can be improved by using the following data.
たとえばデータとして、第１のバッテリ１０１ａ、及び第２のバッテリ１０１ｂが有する単電池の電圧の変化量（ｄＶ）に対する電荷量（電気量とも記す）の変化量（ｄＱ）の割合であるｄＱ／ｄＶを用いることができる。なお、１秒間に１クーロンの電荷が移動するときの電流の大きさが１アンペアである。ｄＱ／ｄＶは第１のバッテリ１０１ａ、及び／又は第２のバッテリ１０１ｂを充電している際に取得が可能である。ＳＯＣ５０％、ＳＯＣ６０％のようにＳＯＣが変わる毎にｄＱ／ｄＶを取得することも可能である。 For example, the data may be dQ/dV, which is the ratio of the change in charge (also written as the amount of electricity) (dQ) to the change in voltage (dV) of the single cells of the first battery 101a and the second battery 101b. Note that the magnitude of the current when 1 coulomb of charge moves per second is 1 ampere. dQ/dV can be obtained when the first battery 101a and/or the second battery 101b are being charged. It is also possible to obtain dQ/dV each time the SOC changes, such as SOC 50% and SOC 60%.
ｄＱ／ｄＶをグラフに示すと曲線をなすことがあり、これをｄＱ／ｄＶ曲線と記すこともある。ｄＱ／ｄＶ曲線では一又は二以上のピークが確認され、当該ピークは曲線に存在する極大値と呼ぶことができる。なお、二以上のピークのうち強度の最も高いものを最大値と呼ぶことができる。 When dQ/dV is plotted on a graph, it may form a curve, which is sometimes referred to as a dQ/dV curve. In a dQ/dV curve, one or more peaks can be identified, and these peaks can be called the maximum values present in the curve. Of the two or more peaks, the one with the highest intensity can be called the maximum value.
各単電池のｄＱ／ｄＶ曲線は蓄積されており、過去と比較することができる。当該比較を利用することで、単電池の劣化を推定することができる。また劣化を推定できるため第２のバッテリ１０１ｂ等の交換時期を予測することができる。 The dQ/dV curves of each cell are stored and can be compared with past data. This comparison can be used to estimate the deterioration of the cells. In addition, because the deterioration can be estimated, it is possible to predict when to replace the second battery 101b, etc.
ここで、単電池の特性の一例として、ＳＯＣに対するＯＣＶ／Ｖの変化を示すグラフを説明する。ＯＣＶ（Ｏｐｅｎ　Ｃｉｒｃｕｉｔ　Ｖｏｌｔａｇｅ）とは開回路電圧、又は開放電圧と呼ばれ、通電していないときの電池の電圧である。ＯＣＶ／Ｖとは、ＯＣＶに対する放電時の電圧（Ｖ）の割合を示す。図７に示すグラフは、ＳＯＣ（％）に対するＯＣＶ／Ｖ（Ｖ）を示すものである。特性０１は第１のバッテリ１０１ａが示す特性であり、特性０２は第２のバッテリ１０１ｂが示す特性とする。 Here, a graph showing the change in OCV/V versus SOC will be described as an example of the characteristics of a single battery. OCV (Open Circuit Voltage) is also called open circuit voltage, and is the voltage of a battery when no current is flowing. OCV/V indicates the ratio of the voltage (V) during discharge to the OCV. The graph shown in Figure 7 shows OCV/V (V) versus SOC (%). Characteristic 01 is the characteristic exhibited by the first battery 101a, and characteristic 02 is the characteristic exhibited by the second battery 101b.
特性０１はＯＣＶ／Ｖ（Ｖ）の変化において、ＳＯＣが１０％以上９０％以下でフラットな領域があり、当該領域はプラトー領域と呼ばれる。プラトー領域はリン酸鉄リチウム（ＬｉＦｅＰＯ４）を正極活物質に用いた場合に生じることがあり、プラトー領域ではＬｉＦｅＰＯ４、及びＦｅＰＯ４が共存している状態といえる。 In the characteristic 01, there is a flat region in the change of OCV/V (V) when the SOC is 10% or more and 90% or less, and this region is called a plateau region. The plateau region may occur when lithium iron phosphate ( LiFePO4 ) is used as the positive electrode active material, and the plateau region is a state in which LiFePO4 and FePO4 coexist.
特性０２はＯＣＶ／Ｖ（Ｖ）が連続的に変化しており、さらに特性０１よりもＯＣＶ／Ｖ（Ｖ）が高いことが特徴である。このような特性を示す正極活物質にはＬＣＯ、又はＮＣＭを用いるとよい。 Characteristic 02 is characterized by a continuous change in OCV/V(V), and a higher OCV/V(V) than characteristic 01. LCO or NCM is a good choice for a positive electrode active material that exhibits such characteristics.
図７のようなグラフを用いて劣化を推定することもできうるが、ＳＯＣが１０％以上９０％以下で変化量の少ないＯＣＶ／Ｖ（Ｖ）を用いた劣化の推定は精度が低くなる場合がある。そのため、図８に示すｄＱ／ｄＶ曲線を用いて、劣化の推定を行うと推定精度を高めることもできるため好ましい。 It is possible to estimate deterioration using a graph like that shown in Figure 7, but estimating deterioration using OCV/V(V), which has little change when the SOC is between 10% and 90%, may result in low accuracy. For this reason, it is preferable to estimate deterioration using the dQ/dV curve shown in Figure 8, as this can improve estimation accuracy.
図８Ａ及び図８Ｂは第１のバッテリ１０１ａに適用できる単電池のｄＱ／ｄＶ曲線の一例である。つまり図８Ａ及び図８Ｂは、図７の特性０１から計算されたｄＱ／ｄＶ曲線といえる。なお、図８Ａ及び図８Ｂにおいて、第１のピーク乃至第３のピークそれぞれに、理解のしやすさのために矢印を示している。図８ＡはＯＣＶ／Ｖに対するｄＱ／ｄＶ曲線であり、電圧が３．３Ｖ以上３．４Ｖ以下に第１のピークが確認され、３．４Ｖを超えて３．５Ｖ以下に第２のピークが確認される。図８Ｂは積算容量に対するｄＱ／ｄＶ曲線であり、積算容量が４８０ｍＡｈ以上６２０ｍＡｈ以下に第３のピークが確認される。いずれのｄＱ／ｄＶ曲線も、図７と比べて変化が明確であり、特に第１のバッテリ１０１ａの出力電圧としてよく使用される範囲、又は積算容量の範囲にピークが確認される。第１のバッテリ１０１ａ等が劣化すると、ピーク位置がシフトする、又はピーク強度が増減するため、劣化の推定として使用しやすいデータといえる。 Figures 8A and 8B are examples of dQ/dV curves of a single cell that can be applied to the first battery 101a. In other words, Figures 8A and 8B can be said to be dQ/dV curves calculated from characteristic 01 in Figure 7. In Figures 8A and 8B, arrows are shown at the first peak to the third peak for ease of understanding. Figure 8A is a dQ/dV curve for OCV/V, and the first peak is confirmed when the voltage is 3.3V or more and 3.4V or less, and the second peak is confirmed when the voltage is more than 3.4V and 3.5V or less. Figure 8B is a dQ/dV curve for integrated capacity, and the third peak is confirmed when the integrated capacity is 480mAh or more and 620mAh or less. In both dQ/dV curves, the changes are clearer than in Figure 7, and peaks are confirmed in the range that is often used as the output voltage of the first battery 101a, or in the range of integrated capacity. When the first battery 101a etc. deteriorates, the peak position shifts or the peak intensity increases or decreases, so this data can be easily used to estimate deterioration.
図９は第２のバッテリ１０１ｂに適用できるバッテリのｄＱ／ｄＶ曲線の一例である。図９のｄＱ／ｄＶ曲線では、第２のバッテリ１０１ｂに対する充放電サイクル数が１（図中サイクル数１と記す）、４００（図中サイクル数４００と記す）のときのものを重ねている。なお第２のバッテリ１０１ｂの負極には黒鉛を用いることとする。なお、図９において、負極のピーク（１）及び正極のピーク（２）それぞれに、理解のしやすさのために矢印を示している。図９より、負極のピーク（１）は電圧３．６Ｖ以上３．８Ｖ以下にて確認され、サイクル数１からサイクル数４００になるにつれて、負極のピーク強度が低下していることがわかる。これより、負極に劣化が生じたと推定される。図９より、正極のピーク（２）は電圧３．８Ｖ以上４．０Ｖ以下にて確認され、負極と同様にサイクル数が増えるにつれて、正極のピーク強度が低下していることがわかる。これより、正極に劣化が生じたと推定される。このように第２のバッテリ１０１ｂの劣化を推定することができる。 Figure 9 is an example of a dQ/dV curve of a battery that can be applied to the second battery 101b. In the dQ/dV curve of Figure 9, the charge/discharge cycle numbers for the second battery 101b are superimposed when they are 1 (referred to as cycle number 1 in the figure) and 400 (referred to as cycle number 400 in the figure). Note that graphite is used for the negative electrode of the second battery 101b. Note that in Figure 9, arrows are shown at the peak (1) of the negative electrode and the peak (2) of the positive electrode for ease of understanding. From Figure 9, it can be seen that the peak (1) of the negative electrode is confirmed at a voltage of 3.6V or more and 3.8V or less, and the peak intensity of the negative electrode decreases as the cycle number increases from 1 to 400. From this, it is estimated that deterioration has occurred in the negative electrode. From Figure 9, it can be seen that the peak (2) of the positive electrode is confirmed at a voltage of 3.8V or more and 4.0V or less, and as with the negative electrode, the peak intensity of the positive electrode decreases as the cycle number increases. From this, it is estimated that degradation has occurred in the positive electrode. In this way, it is possible to estimate the degradation of the second battery 101b.
図７に示したグラフの元となるデータは、第１のセンサ回路１０２ａ、第２のセンサ回路１０２ｂにより取得することができ、ｄＱ／ｄＶはマイコン１５０ａにより演算することができる。第１のセンサ回路１０２ａ、第２のセンサ回路１０２ｂにより取得するデータは充電時に毎回取得すると精度の高い推定可能となり好ましい。上述したデータは、ＣＡＮ２５などを介して、クラウドに保存しておいてもよい。さらに上述したデータ又は劣化の推定等は、電気自動車１１と連動した電子機器から閲覧できるようにしてもよい。 The data on which the graph shown in FIG. 7 is based can be obtained by the first sensor circuit 102a and the second sensor circuit 102b, and dQ/dV can be calculated by the microcomputer 150a. It is preferable to obtain the data from the first sensor circuit 102a and the second sensor circuit 102b every time charging, as this allows for highly accurate estimation. The above-mentioned data may be stored in the cloud via the CAN 25 or the like. Furthermore, the above-mentioned data or degradation estimates, etc. may be made viewable from an electronic device linked to the electric vehicle 11.
劣化の推定に加えて、ＢＭＳ１５０は第１のバッテリ１０１ａ、及び／又は第２のバッテリ１０１ｂの出力を制御することができる。具体的にはＢＭＳ１５０からの制御信号に基づき、第１のＤＣ／ＤＣ回路１０７ａ、及び／又は第２のＤＣ／ＤＣ回路１０７ｂを制御する。 In addition to estimating the deterioration, the BMS 150 can control the output of the first battery 101a and/or the second battery 101b. Specifically, the BMS 150 controls the first DC/DC circuit 107a and/or the second DC/DC circuit 107b based on a control signal from the BMS 150.
＜温度センサ＞
図示しないが、本発明の一態様であるバッテリ制御システム１０は、温度センサを有するとよい。温度センサは、バッテリ１０１の温度が検出できる位置に設けられるとよい。温度センサとしてサーミスタを用いることができる。サーミスタの接触部をバッテリ１０１に接触させて、当該接触部の抵抗値の変化を検出してバッテリ１０１の温度を算出することができる。バッテリ１０１は第１のバッテリ１０１ａ、及び第２のバッテリ１０１ｂに読み替えることができる。 <Temperature sensor>
Although not shown, the battery control system 10 according to one embodiment of the present invention may include a temperature sensor. The temperature sensor may be provided at a position where the temperature of the battery 101 can be detected. A thermistor may be used as the temperature sensor. A contact portion of the thermistor is brought into contact with the battery 101, and a change in the resistance value of the contact portion is detected to calculate the temperature of the battery 101. The battery 101 may be replaced with a first battery 101a and a second battery 101b.
＜バッテリ制御システムのフローチャート１＞
上記記載を踏まえて、バッテリ制御システム１０を用いたフローチャートの例を図１０及び図１１を用いて説明する。 <Flowchart 1 of the battery control system>
Based on the above description, an example of a flowchart using the battery control system 10 will be described with reference to FIGS.
図１０のステップＳ５１及びステップＳ５２に示すように、電気自動車１１を駐車する際、普通充電用充電口１９ａに充電スタンドのコネクタを接続しておく。このとき、ステップＳ５３に示すように、先に第１のバッテリ１０１ａの充電を開始する。充電の際、ステップＳ５４に示すように第１の電流センサ１０４ａを用いて第１のバッテリ１０１ａの充電電流を検出する。またステップＳ５５に示すように第１の電圧センサ１０３ａを用いて第１のバッテリ１０１ａの充電電圧を検出する。なお、ステップＳ５４とステップＳ５５とは順序を入れ替えてもよいし、同じステップで検出することもできる。その後、ステップＳ５６に示すように第１のバッテリ１０１ａの充電を終了する。なお、検出された電流値及び電圧値は記録しておき、ステップＳ５７に示すように、上記電流値及び電圧値を用いて、マイコン１５０ａによりｄＱ／ｄＶを計算する。その後、ステップＳ５８に示すように、過去の充電におけるｄＱ／ｄＶとの比較を行い、ステップＳ５９に示すように、第１のバッテリ１０１ａの劣化を推定する。 As shown in steps S51 and S52 of FIG. 10, when the electric vehicle 11 is parked, the connector of the charging station is connected to the normal charging port 19a. At this time, as shown in step S53, charging of the first battery 101a is started first. During charging, as shown in step S54, the charging current of the first battery 101a is detected using the first current sensor 104a. Also, as shown in step S55, the charging voltage of the first battery 101a is detected using the first voltage sensor 103a. Note that the order of steps S54 and S55 may be reversed, or they may be detected in the same step. After that, as shown in step S56, charging of the first battery 101a is terminated. Note that the detected current value and voltage value are recorded, and as shown in step S57, the microcomputer 150a calculates dQ/dV using the current value and voltage value. After that, as shown in step S58, a comparison is made with dQ/dV in past charging, and as shown in step S59, the deterioration of the first battery 101a is estimated.
上述したステップＳ５６の第１のバッテリ１０１ａ充電終了後は、ステップＳ６１に示す第２のバッテリ１０１ｂの充電を開始することができる。第２のバッテリ１０１ｂを第１のバッテリ１０１ａより先に充電してもよい。また第１のバッテリ１０１ａと第２のバッテリ１０１ｂは同じステップで充電してもよい。充電の際、ステップＳ６２に示すように第２の電流センサ１０４ｂを用いて第２のバッテリ１０１ｂの充電電流を検出する。またステップＳ６３に示すように第２の電圧センサ１０３ｂを用いて第２のバッテリ１０１ｂの充電電圧を検出する。なお、ステップＳ６２とステップＳ６３とは順序を入れ替えてもよいし、同じステップで検出することもできる。その後、ステップＳ６４に示すように第２のバッテリ１０１ｂの充電を終了する。なお、検出された電流値及び電圧値は記録しておき、ステップＳ６５に示すように、上記電流値及び電圧値を用いて、ＢＭＳ１５０によりｄＱ／ｄＶを計算する。その後、ステップＳ６６に示すように、過去の充電におけるｄＱ／ｄＶとの比較を行い、ステップＳ６７に示すように、第２のバッテリ１０１ｂの状態を推定する。 After the charging of the first battery 101a is completed in step S56, the charging of the second battery 101b can be started as shown in step S61. The second battery 101b may be charged before the first battery 101a. The first battery 101a and the second battery 101b may be charged in the same step. During charging, the charging current of the second battery 101b is detected using the second current sensor 104b as shown in step S62. The charging voltage of the second battery 101b is detected using the second voltage sensor 103b as shown in step S63. Note that the order of steps S62 and S63 may be reversed, or they may be detected in the same step. Thereafter, the charging of the second battery 101b is terminated as shown in step S64. Note that the detected current value and voltage value are recorded, and as shown in step S65, the BMS 150 calculates dQ/dV using the current value and voltage value. Then, as shown in step S66, a comparison is made with dQ/dV from previous charging, and as shown in step S67, the state of the second battery 101b is estimated.
以上により充電が完了する。次いでステップＳ７１に示すように普通充電用充電口１９ａからコネクタを抜き取ったあと、ステップＳ７２に示すように電気自動車１１の走行を開始する。 This completes charging. Next, as shown in step S71, the connector is removed from the normal charging port 19a, and then the electric vehicle 11 starts traveling as shown in step S72.
図１０の（Ｘ）から図１１の（Ｘ）へフローが移行する。その後図１１のステップＳ７３に示すように、走行開始時は第２のバッテリ１０１ｂから放電させる。走行開始時に第１のバッテリ１０１ａを使用しないことにより、第１のバッテリ１０１ａの寿命を延ばすことができる。その後ステップＳ７４に示すように、ＢＭＳ１５０により推定された第１のバッテリ１０１ａの劣化が許容されるべきか否かを判断し、適切であれば、ステップＳ７５に示すように第１のバッテリ１０１ａからの放電を開始する。第２のバッテリ１０１ｂからの放電は停止してもよいし、第２のバッテリ１０１ｂの放電と同じステップで第１のバッテリ１０１ａの放電を実行してもよい。上記第１のバッテリ１０１ａの劣化が許容されない場合、ステップＳ７６に示すように、第２のバッテリ１０１ｂからの放電を継続する。 The flow shifts from (X) in FIG. 10 to (X) in FIG. 11. Then, as shown in step S73 in FIG. 11, the second battery 101b is discharged at the start of traveling. By not using the first battery 101a at the start of traveling, the life of the first battery 101a can be extended. Then, as shown in step S74, it is determined whether the deterioration of the first battery 101a estimated by the BMS 150 should be tolerated, and if appropriate, discharging from the first battery 101a is started as shown in step S75. Discharging from the second battery 101b may be stopped, or discharging of the first battery 101a may be performed in the same step as discharging of the second battery 101b. If the deterioration of the first battery 101a is not tolerated, discharging from the second battery 101b is continued as shown in step S76.
その後、ステップＳ７７に示すように、電気自動車１１を駐車する。 Then, as shown in step S77, the electric vehicle 11 is parked.
＜バッテリ制御システムのフローチャート２＞
バッテリ制御システム１０を用いた別のフローチャートの例を図１０乃至図１２を用いて説明する。 <Flowchart 2 of the battery control system>
Another example of a flowchart using the battery control system 10 will be described with reference to FIGS.
上記のとおり図１０のフローチャートを行った後に、図１１の（Ｙ）から図１２の（Ｙ）へフローが移行する。その後図１２のステップＳ８１に示すように、カレンダー劣化が生じ始める期間（Ｄ）より、電気自動車１１の駐車期間が長いか短いかを判定する。ＶＣＵ２１、ＣＡＮ２５、又はＢＭＳ１５０により、上記期間（Ｄ）を判定することができる。カレンダー劣化が生じる期間（Ｄ）以上の駐車であると判定された場合、ステップＳ８２に示すように、第１のバッテリ１０１ａの劣化が発生しづらいＳＯＣとなるように、第１のバッテリ１０１ａと第２のバッテリ１０１ｂとの間の電力の転送を開始する。当該転送後、第１のバッテリ１０１ａのＳＯＣは１００％未満、好ましくは９０％以下、さらに好ましくは８０％以下とすることができる。 After executing the flowchart of FIG. 10 as described above, the flow shifts from (Y) of FIG. 11 to (Y) of FIG. 12. Then, as shown in step S81 of FIG. 12, it is determined whether the parking period of the electric vehicle 11 is longer or shorter than the period (D) in which calendar deterioration begins to occur. The period (D) can be determined by the VCU 21, the CAN 25, or the BMS 150. If it is determined that the parking period is longer than the period (D) in which calendar deterioration occurs, as shown in step S82, the transfer of power between the first battery 101a and the second battery 101b is started so that the SOC of the first battery 101a is such that deterioration is unlikely to occur. After the transfer, the SOC of the first battery 101a can be less than 100%, preferably 90% or less, and more preferably 80% or less.
ステップＳ８１に示す判定において、期間（Ｄ）以下であると判定された場合であっても、ステップＳ８３に示すように、電気自動車１１と連動した電子機器、たとえばスマートホンからカレンダー劣化を考慮するモードとなる信号ＤｘがＣＡＮ２５、又はＢＭＳ１５０に送信されたときもステップＳ８２に示すように、第１のバッテリ１０１ａのＳＯＣがカレンダー劣化しづらい値となるように、第１のバッテリ１０１ａと第２のバッテリ１０１ｂとの間の転送を開始することができる。 Even if it is determined in step S81 that the period is equal to or less than the period (D), when a signal Dx that switches to a mode that takes calendar deterioration into consideration is transmitted from an electronic device linked to the electric vehicle 11, such as a smartphone, to the CAN 25 or the BMS 150 as shown in step S83, transfer between the first battery 101a and the second battery 101b can be started as shown in step S82 so that the SOC of the first battery 101a becomes a value that is less susceptible to calendar deterioration.
その後、ステップＳ８４に示すように、電気自動車１１の走行を開始することができる。 After that, as shown in step S84, the electric vehicle 11 can start traveling.
以上のとおり、本発明の一形態であるバッテリ制御システムにより、第１のバッテリ１０１ａの劣化を抑制することが可能になる。 As described above, the battery control system according to one embodiment of the present invention makes it possible to suppress deterioration of the first battery 101a.
本実施の形態は、他の実施の形態と適宜組み合わせて用いることができる。 This embodiment can be used in appropriate combination with other embodiments.
（実施の形態２）
本実施の形態では、上記実施の形態に適用できるバッテリの構成について説明する。本実施の形態で示すバッテリは、第１のバッテリ１０１ａ又は第２のバッテリ１０１ｂに適用できる。具体的には図１３を用いて単電池の正極を説明する。 (Embodiment 2)
In this embodiment mode, a structure of a battery that can be applied to the above embodiment mode will be described. The battery shown in this embodiment mode can be applied to the first battery 101a or the second battery 101b. Specifically, the positive electrode of a single cell will be described with reference to FIG. 13.
［正極］
図１３Ａは単電池が有する正極の断面図の一例を示している。正極は、正極集電体５５０上に正極活物質層５７１を有する。正極活物質層５７１は正極活物質５６１、正極活物質５６２、導電材５５３、導電材５５４、及び空隙を有する。空隙には電解質５５６が含浸されている。また図示しないが正極活物質層５７１はバインダ（結着剤）も有する。 [Positive electrode]
13A shows an example of a cross-sectional view of a positive electrode of a single cell. The positive electrode has a positive electrode active material layer 571 on a positive electrode current collector 550. The positive electrode active material layer 571 has a positive electrode active material 561, a positive electrode active material 562, a conductive material 553, a conductive material 554, and a gap. The gap is impregnated with an electrolyte 556. Although not shown, the positive electrode active material layer 571 also has a binder (binding agent).
正極活物質５６１は正極活物質５６２よりメディアン径（Ｄ５０）が大きい正極活物質の例である。メディアン径（Ｄ５０）の異なる正極活物質を用いることで、正極活物質のタップ密度を高めることが可能になる。導電材５５３は導電材５５４と形状が異なる導電材の例である。導電材５５３は粒子状であり、導電材５５４はシート状、又は繊維状であるとよい。 Positive electrode active material 561 is an example of a positive electrode active material having a larger median diameter (D50) than positive electrode active material 562. By using positive electrode active materials having different median diameters (D50), it is possible to increase the tap density of the positive electrode active material. Conductive material 553 is an example of a conductive material having a different shape from conductive material 554. Conductive material 553 is preferably in the form of particles, and conductive material 554 is preferably in the form of a sheet or fiber.
［正極集電体］
正極集電体５５０としては導電性が高い材料を用いることができ、具体的には銅、金、白金、アルミニウム、鉄又はチタン等の金属、及び上記金属の合金などを用いるとよい。また鉄の合金としてステンレスが挙げられる。また正極集電体５５０には、正極の電位で溶出しない金属又は合金が用いられるとよい。また正極集電体５５０には、シリコン、チタン、ネオジム、スカンジウム、又はモリブデンなどの耐熱性を向上させる元素が添加されたアルミニウム合金を用いるとよい。また正極集電体５５０には、シリコンと反応してシリサイドを形成する金属、例えば上記チタンを用いるとよい。シリコンと反応してシリサイドを形成する金属元素として上記チタン以外に、ジルコニウム、ハフニウム、バナジウム、ニオブ、タンタル、クロム、モリブデン、タングステン、コバルト、又はニッケル等がある。 [Positive electrode current collector]
The positive electrode current collector 550 may be made of a material having high electrical conductivity, specifically, metals such as copper, gold, platinum, aluminum, iron, or titanium, and alloys of the above metals. Stainless steel may be used as an iron alloy. The positive electrode current collector 550 may be made of a metal or alloy that does not dissolve at the potential of the positive electrode. The positive electrode current collector 550 may be made of an aluminum alloy to which an element that improves heat resistance, such as silicon, titanium, neodymium, scandium, or molybdenum, is added. The positive electrode current collector 550 may be made of a metal that reacts with silicon to form a silicide, such as the above titanium. Metal elements that react with silicon to form a silicide include, in addition to the above titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, or nickel.
正極集電体５５０の厚みは、５μｍ以上３０μｍ以下、好ましくは１０μｍ以上２０μｍ以下がよく、シート状又は板状をなすとよい。正極集電体５５０にはパンチングメタル加工、又はエキスパンドメタル加工を施してもよい。パンチングメタル加工は打ち抜き加工であり、エキスパンドメタル加工は切れ目を入れて引き伸ばす加工である。上記パンチングメタル加工及びエキスパンドメタル加工を経ると、円状、楕円又は菱形状等の開口が設けられた網目状の正極集電体５５０となる。上記開口を有する正極集電体５５０を用いると、軽量化された電池セルを得ることもできる。 The thickness of the positive electrode collector 550 is preferably 5 μm to 30 μm, more preferably 10 μm to 20 μm, and may be in the form of a sheet or plate. The positive electrode collector 550 may be subjected to punching or expanded metal processing. The punching metal processing is a punching process, and the expanded metal processing is a process in which cuts are made and the material is stretched. Through the punching metal processing and expanded metal processing, the positive electrode collector 550 becomes a mesh-like material with circular, elliptical, or diamond-shaped openings. By using the positive electrode collector 550 with the above openings, a lightweight battery cell can be obtained.
［正極活物質］
再掲するが図１３Ａには正極活物質５６１及び正極活物質５６２を示し、これらは正極活物質粒子と呼ばれることがある。ただし、正極活物質の形状は粒子状以外の多様な形状をとる。たとえば図１３Ｂに示すように正極活物質５６１の断面形状は楕円形、長方形、台形、錐形、角が丸まった四角形、非対称の形状であってもよい。なお正極の作製工程でのプレスにより、粒子状であった正極活物質も図１３Ｂに示すような形状へ変形することがある。図１３Ｂにおいてその他の構成は、図１３Ａと同様である。 [Positive electrode active material]
Again, FIG. 13A shows a positive electrode active material 561 and a positive electrode active material 562, which are sometimes called positive electrode active material particles. However, the shape of the positive electrode active material may be various shapes other than particulate. For example, as shown in FIG. 13B, the cross-sectional shape of the positive electrode active material 561 may be elliptical, rectangular, trapezoidal, pyramidal, rectangular with rounded corners, or asymmetrical. Note that the particulate positive electrode active material may be deformed into the shape shown in FIG. 13B by pressing in the positive electrode manufacturing process. Other configurations in FIG. 13B are the same as those in FIG. 13A.
正極活物質５６１及び正極活物質５６２は一次粒子、又は二次粒子のいずれであってもよい。なお、本明細書において、一次粒子とは、ＳＥＭ（走査電子顕微鏡）などにより例えば５０００倍で観察した際、粒界を有さない最小単位の粒子（塊）を指し、単粒子と呼ばれることもある。また二次粒子とは、上記一次粒子が、上記粒界（一次粒子の外周等）の一部を共有するように凝集した粒子（他と独立した粒子）を指す。すなわち二次粒子は粒界を有する。 The positive electrode active material 561 and the positive electrode active material 562 may be either primary particles or secondary particles. In this specification, a primary particle refers to a particle (lump) that is the smallest unit that does not have grain boundaries when observed at, for example, 5000 times magnification using a SEM (scanning electron microscope) or the like, and is sometimes called a single particle. A secondary particle refers to a particle (particle independent of others) in which the primary particles are aggregated so as to share part of the grain boundary (such as the outer periphery of the primary particle). In other words, a secondary particle has a grain boundary.
正極活物質５６１及び正極活物質５６２はキャリアイオンの挿入及び脱離が可能な材料を用いることができる。キャリアイオンはリチウムイオン、ナトリウムイオン、カリウムイオン、カルシウムイオン、ストロンチウムイオン、バリウムイオン、ベリリウムイオン、又はマグネシウムイオンを用いることができる。 The positive electrode active material 561 and the positive electrode active material 562 can be made of a material capable of inserting and removing carrier ions. The carrier ions can be lithium ions, sodium ions, potassium ions, calcium ions, strontium ions, barium ions, beryllium ions, or magnesium ions.
リチウムイオンの挿入及び脱離が可能な材料として、オリビン型の結晶構造、層状岩塩型の結晶構造、又はスピネル型の結晶構造を有するリチウム複合酸化物等がある。 Materials capable of inserting and extracting lithium ions include lithium composite oxides having an olivine type crystal structure, a layered rock salt type crystal structure, or a spinel type crystal structure.
例えば、オリビン型の結晶構造を有するリチウム複合酸化物は、ＬｉＭＰＯ４（ここでＭ＝Ｆｅ，Ｍｎ，Ｎｉ，Ｃｏのいずれか一以上を有する）と表される。Ｆｅ及びＭｎは熱安定性にも優れていることから、ＭとしてＦｅ、若しくはＭｎを用いる、又はＭとしてＦｅ及びＭｎを用いると正極活物質として好適である。ＭとしてＦｅを用いた場合、ＬｉＦｅＰＯ４と表され、これをＬＦＰと記すことがある。ＬＦＰはリチウム、鉄及び燐を有する複合酸化物と記すことがあり、例示した元素以外の元素、さらには容量に寄与しない元素を有してもよい。ＬＦＰは安全性が高いため、第１のバッテリ１０１ａに用いると好ましい。 For example, a lithium composite oxide having an olivine crystal structure is represented as LiMPO 4 (where M=one or more of Fe, Mn, Ni, and Co). Since Fe and Mn are also excellent in thermal stability, it is suitable as a positive electrode active material when Fe or Mn is used as M, or when Fe and Mn are used as M. When Fe is used as M, it is represented as LiFePO 4 , which may be written as LFP. LFP may be written as a composite oxide having lithium, iron, and phosphorus, and may have elements other than the exemplified elements, and further elements that do not contribute to the capacity. Since LFP is highly safe, it is preferable to use it for the first battery 101a.
また、例えば層状岩塩型の結晶構造を有するリチウム複合酸化物は、ＬｉＭＯ２（ここでＭ＝Ｆｅ，Ｍｎ，Ｎｉ，Ｃｏのいずれか一以上を有する）と表され、ＭがコバルトのときＬＣＯとなる。ＬＣＯは上述したマグネシウム等の添加元素を表層部に有すると好ましい。表層部とは活物質の表面から５０ｎｍまでの領域、好ましくは３０ｎｍまでの領域、さらに好ましくは１０ｎｍまでの領域を指す。 For example, a lithium composite oxide having a layered rock salt type crystal structure is expressed as LiMO2 (where M=one or more of Fe, Mn, Ni, and Co), and when M is cobalt, it becomes LCO. It is preferable that LCO has an additive element such as magnesium as described above in the surface layer. The surface layer refers to a region up to 50 nm from the surface of the active material, preferably up to 30 nm, and more preferably up to 10 nm.
さらに層状岩塩型の結晶構造を有するリチウム複合酸化物として、ＬｉＮｉｘＣｏｙＭｎｚＯ２（ｘ＞０、ｙ＞０、０．８＜ｘ＋ｙ＋ｚ＜１．２）でと表されるＮｉＣｏＭｎ系がある。ＬｉＮｉｘＣｏｙＭｎｚＯ２（ｘ＞０、ｙ＞０、０．８＜ｘ＋ｙ＋ｚ＜１．２）はＮＣＭと記すことがある。ＬｉＮｉｘＣｏｙＭｎｚＯ２において、例えば、０．１ｘ＜ｙ＜８ｘかつ０．１ｘ＜ｚ＜８ｘを満たすことが好ましい。具体例として、ｘ、ｙ及びｚは、ｘ：ｙ：ｚ＝１：１：１又はその近傍の値を満たすことが好ましい。また別の具体例として、ｘ、ｙ及びｚは、ｘ：ｙ：ｚ＝５：２：３又はその近傍の値を満たすことが好ましい。また別の具体例として、ｘ、ｙ及びｚは、ｘ：ｙ：ｚ＝８：１：１又はその近傍の値を満たすことが好ましい。また別の具体例として、ｘ、ｙ及びｚは、ｘ：ｙ：ｚ＝９：０．５：０．５又はその近傍の値を満たすことが好ましい。また別の具体例として、ｘ、ｙ及びｚは、ｘ：ｙ：ｚ＝６：２：２又はその近傍の値を満たすことが好ましい。また別の具体例として、ｘ、ｙ及びｚは、ｘ：ｙ：ｚ＝１：４：１又はその近傍の値を満たすことが好ましい。ＮＣＭはＮｉ、Ｃｏ及びＭｎを有するリチウム複合酸化物と記すことがあり、又はＬｉ、Ｎｉ、Ｃｏ及びＭｎを有する複合酸化物と記すことがある。 Furthermore, as a lithium composite oxide having a layered rock salt type crystal structure, there is a NiCoMn system represented by LiNi x Co y Mn z O 2 (x>0, y>0, 0.8<x+y+z<1.2). LiNi x Co y Mn z O 2 (x>0, y>0, 0.8<x+y+z<1.2) may be written as NCM. In LiNi x Co y Mn z O 2 , for example, it is preferable that 0.1x<y<8x and 0.1x<z<8x are satisfied. As a specific example, it is preferable that x, y, and z satisfy x:y:z=1:1:1 or a value in the vicinity thereof. As another specific example, it is preferable that x, y, and z satisfy x:y:z=5:2:3 or a value in the vicinity thereof. As another specific example, x, y, and z preferably satisfy x:y:z=8:1:1 or a value in the vicinity thereof. As another specific example, x, y, and z preferably satisfy x:y:z=9:0.5:0.5 or a value in the vicinity thereof. As another specific example, x, y, and z preferably satisfy x:y:z=6:2:2 or a value in the vicinity thereof. As another specific example, x, y, and z preferably satisfy x:y:z=1:4:1 or a value in the vicinity thereof. NCM may be referred to as a lithium composite oxide having Ni, Co, and Mn, or may be referred to as a composite oxide having Li, Ni, Co, and Mn.
また、上記ＮＣＭにおいて、カルシウム、ボロン、ガリウム、アルミニウム、ホウ素及びインジウムから選ばれた一又は二以上を、０．１ａｔｏｍｉｃ％以上３ａｔｏｍｉｃ％以下の濃度で有してもよい。上記濃度のカルシウム、ボロン、ガリウム、アルミニウム、ホウ素及びインジウムを添加元素と記すことがある。添加元素は活物質の表層部に位置するとよい。二次粒子の場合には、添加元素は粒界に有するとよい。 The NCM may also contain one or more elements selected from calcium, boron, gallium, aluminum, boron, and indium at a concentration of 0.1 atomic % or more and 3 atomic % or less. The above concentrations of calcium, boron, gallium, aluminum, boron, and indium may be referred to as additive elements. The additive element is preferably located in the surface layer of the active material. In the case of secondary particles, the additive element is preferably located at the grain boundary.
この他にも、ナトリウムイオンの挿入及び脱離が可能な材料として、ＮａＦｅＯ２、ＮａＮｉＯ２、ＮａＣｏＯ２、ＮａＭｎＯ２、ＮａＶＯ２、Ｎａ（ＮｉＸＭｎ１−Ｘ）Ｏ２（０＜Ｘ＜１）、Ｎａ（ＦｅＸＭｎ１−Ｘ）Ｏ２（０＜Ｘ＜１）、ＮａＶＰＯ４Ｆ、Ｎａ２ＦｅＰＯ４Ｆ、Ｎａ３Ｖ２（ＰＯ４）３等を挙げることができる。 Other examples of materials capable of inserting and desorbing sodium ions include NaFeO2 , NaNiO2 , NaCoO2 , NaMnO2 , NaVO2 , Na( NiXMn1-X ) O2 (0<X< 1 ), Na( FeXMn1 -X ) O2 (0<X<1), NaVPO4F , Na2FePO4F , and Na3V2 ( PO4 ) 3 .
［バインダ］
バインダは、正極集電体５５０から正極活物質５６１、正極活物質５６２、導電材５５３、導電材５５４が滑落しないように備えられている。またバインダは、正極活物質５６１と導電材５５３とをつなぎとめる役割を果たす。同様にバインダは正極活物質５６２と導電材５５３とをつなぎとめる役割も果たす。同様にバインダは正極活物質５６１と導電材５５４とをつなぎとめる役割も果たす。同様にバインダは正極活物質５６２と導電材５５４とをつなぎとめる役割も果たす。そのためバインダは、正極集電体５５０と接するように位置するもの、正極活物質５６１と導電材５５３又は導電材５５４との間に位置するもの、正極活物質５６２と導電材５５３又は導電材５５４との間に位置するもの、導電材５５３と絡まるように位置するもの、導電材５５４と絡まるように位置するものがある。 [Binder]
The binder is provided so that the positive electrode active material 561, the positive electrode active material 562, the conductive material 553, and the conductive material 554 do not slip off from the positive electrode collector 550. The binder also plays a role of binding the positive electrode active material 561 and the conductive material 553. Similarly, the binder also plays a role of binding the positive electrode active material 562 and the conductive material 553. Similarly, the binder also plays a role of binding the positive electrode active material 561 and the conductive material 554. Similarly, the binder also plays a role of binding the positive electrode active material 562 and the conductive material 554. Therefore, there are binders positioned so as to contact the positive electrode collector 550, those positioned between the positive electrode active material 561 and the conductive material 553 or the conductive material 554, those positioned between the positive electrode active material 562 and the conductive material 553 or the conductive material 554, those positioned so as to be entangled with the conductive material 553, and those positioned so as to be entangled with the conductive material 554.
バインダとしては、例えば、スチレン−ブタジエンゴム（ＳＢＲ）、スチレン−イソプレン−スチレンゴム、アクリロニトリル−ブタジエンゴム、ブタジエンゴム、エチレン−プロピレン−ジエン共重合体などのゴム材料を用いることが好ましい。またバインダとして、フッ素ゴムを用いることができる。 As the binder, it is preferable to use a rubber material such as styrene-butadiene rubber (SBR), styrene-isoprene-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, or ethylene-propylene-diene copolymer. Furthermore, fluororubber can be used as the binder.
また、バインダとしては、例えば水溶性の高分子を用いることが好ましい。水溶性の高分子としては、例えば多糖類などを用いることができる。多糖類としては、カルボキシメチルセルロース（ＣＭＣ）、メチルセルロース、エチルセルロース、ヒドロキシプロピルセルロース、ジアセチルセルロース、再生セルロースなどのセルロース誘導体、又は澱粉などを用いることができる。また、これらの水溶性の高分子を、前述のゴム材料と併用して用いると、さらに好ましい。 In addition, it is preferable to use, for example, a water-soluble polymer as the binder. For example, polysaccharides can be used as the water-soluble polymer. For example, cellulose derivatives such as carboxymethyl cellulose (CMC), methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, and regenerated cellulose, or starch can be used as the polysaccharide. It is even more preferable to use these water-soluble polymers in combination with the above-mentioned rubber material.
また、バインダとしては、ポリスチレン、ポリアクリル酸メチル、ポリメタクリル酸メチル（ポリメチルメタクリレート、ＰＭＭＡ）、ポリアクリル酸ナトリウム、ポリビニルアルコール（ＰＶＡ）、ポリエチレンオキシド（ＰＥＯ）、ポリプロピレンオキシド、ポリイミド、ポリ塩化ビニル、ポリテトラフルオロエチレン、ポリエチレン、ポリプロピレン、ポリイソブチレン、ポリエチレンテレフタレート、ナイロン、ポリフッ化ビニリデン（ＰＶＤＦ）、ポリアクリロニトリル（ＰＡＮ）、エチレンプロピレンジエンポリマー、ポリ酢酸ビニル、ニトロセルロース等の材料を用いることが好ましい。 Furthermore, as the binder, it is preferable to use materials such as polystyrene, polymethyl acrylate, polymethyl methacrylate (polymethyl methacrylate, PMMA), sodium polyacrylate, polyvinyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide, polyimide, polyvinyl chloride, polytetrafluoroethylene, polyethylene, polypropylene, polyisobutylene, polyethylene terephthalate, nylon, polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), ethylene propylene diene polymer, polyvinyl acetate, and nitrocellulose.
バインダは上記のうち複数を組み合わせて使用してもよい。 You may use a combination of multiple binders from the above.
例えばバインダは、粘度調整効果の特に優れた材料と、他の材料とを組み合わせて使用してもよい。例えばゴム材料等は接着力及び弾性力に優れる反面、溶媒に混合した場合に粘度調整が難しい場合がある。このような場合には例えば、粘度調整効果の特に優れた材料と混合することが好ましい。粘度調整効果の特に優れた材料としては、例えば水溶性高分子を用いるとよい。また、粘度調整効果に特に優れた水溶性高分子としては、前述の多糖類、例えばカルボキシメチルセルロース（ＣＭＣ）、メチルセルロース、エチルセルロース、ヒドロキシプロピルセルロース及びジアセチルセルロース、再生セルロースなどのセルロース誘導体、又は澱粉を用いることができる。 For example, the binder may be a combination of a material with a particularly excellent viscosity adjustment effect and another material. For example, while rubber materials have excellent adhesive strength and elasticity, it may be difficult to adjust the viscosity when mixed with a solvent. In such cases, it is preferable to mix the binder with a material with a particularly excellent viscosity adjustment effect. For example, a water-soluble polymer may be used as a material with a particularly excellent viscosity adjustment effect. In addition, as a water-soluble polymer with a particularly excellent viscosity adjustment effect, the above-mentioned polysaccharides, for example, carboxymethylcellulose (CMC), methylcellulose, ethylcellulose, hydroxypropylcellulose, and diacetylcellulose, cellulose derivatives such as regenerated cellulose, or starch may be used.
なお、カルボキシメチルセルロースなどのセルロース誘導体は、例えばカルボキシメチルセルロースのナトリウム塩又はアンモニウム塩などの塩とすることにより溶解度が上がり、粘度調整剤としての効果を発揮しやすくなる。溶解度が高くなることにより電極のスラリーを作製する際に活物質又は他の構成要素との分散性を高めることもできる。本明細書等においては、電極のバインダとして使用するセルロース及びセルロース誘導体としては、それらの塩も含むものとする。 The solubility of cellulose derivatives such as carboxymethylcellulose can be increased by converting them into salts such as sodium salt or ammonium salt of carboxymethylcellulose, making them more effective as viscosity adjusters. Increasing the solubility can also increase the dispersibility with the active material or other components when preparing the electrode slurry. In this specification, the cellulose and cellulose derivatives used as electrode binders include their salts.
水溶性高分子は水に溶解することにより粘度を安定化させ、活物質及びバインダとして組み合わせる他の材料、例えばスチレンブタジエンゴムを水溶液中に安定して分散させることができる。また、官能基を有するために活物質表面に安定に吸着しやすいことが期待される。また、例えばカルボキシメチルセルロースなどのセルロース誘導体は、水酸基又はカルボキシル基などの官能基を有する材料が多く、官能基を有するために高分子同士が相互作用し、活物質表面を広く覆って存在することが期待される。 Water-soluble polymers stabilize the viscosity by dissolving in water, and can stably disperse the active material and other materials to be combined as a binder, such as styrene-butadiene rubber, in an aqueous solution. In addition, because they have functional groups, they are expected to be easily and stably adsorbed onto the surface of the active material. Furthermore, many cellulose derivatives, such as carboxymethyl cellulose, have functional groups such as hydroxyl groups or carboxyl groups, and because they have functional groups, the polymers are expected to interact with each other and widely cover the surface of the active material.
［導電材］
正極活物質５６１及び／又は正極活物質５６２は複合酸化物のため抵抗が高いことがあり、正極活物質５６１及び／又は正極活物質５６２から正極集電体５５０へ電流を集めることが難しくなる。その場合、図１３Ａに示すように正極は導電材５５３及び導電材５５４を有し、導電材５５３及び導電材５５４が正極活物質５６１と正極集電体５５０との間の電流パス、複数の正極活物質５６１間の電流パス、複数の正極活物質間と正極集電体５５０との間の電流パス、正極活物質５６２と正極集電体５５０との間の電流パス、複数の正極活物質５６２間の電流パス等を補助する機能を果たす。導電材は、その役割から導電付与剤、導電助剤とも呼ばれる。なお、導電材を増やすと正極活物質の割合が減少してしまうため、導電材５５３及び導電材５５４はいずれか一方であってもよい。 [Conductive material]
The positive electrode active material 561 and/or the positive electrode active material 562 may have high resistance because of a composite oxide, and it becomes difficult to collect current from the positive electrode active material 561 and/or the positive electrode active material 562 to the positive electrode current collector 550. In that case, as shown in FIG. 13A, the positive electrode has a conductive material 553 and a conductive material 554, and the conductive material 553 and the conductive material 554 function to assist the current path between the positive electrode active material 561 and the positive electrode current collector 550, the current path between the multiple positive electrode active materials 561, the current path between the multiple positive electrode active materials and the positive electrode current collector 550, the current path between the positive electrode active material 562 and the positive electrode current collector 550, the current path between the multiple positive electrode active materials 562, and the like. The conductive material is also called a conductive agent or a conductive assistant due to its role. Note that, since increasing the conductive material reduces the proportion of the positive electrode active material, the conductive material 553 and the conductive material 554 may be either one of them.
このような機能を果たすために導電材５５３及び導電材５５４は正極活物質５６１より抵抗の低い材料を有するとよい。または導電材５５３及び導電材５５４は正極活物質５６２より抵抗の低い材料を有するとよい。 To achieve this function, the conductive material 553 and the conductive material 554 may have a material with lower resistance than the positive electrode active material 561. Alternatively, the conductive material 553 and the conductive material 554 may have a material with lower resistance than the positive electrode active material 562.
導電材は、代表的には炭素材料又は金属材料が用いられる。導電材５５３としてカーボンブラック（ファーネスブラック、アセチレンブラック、黒鉛など）がある。カーボンブラックは正極活物質５６１より小さな粒径を有するものが多い。導電材５５４としてカーボンナノチューブ（ＣＮＴ）、ＶＧＣＦ（登録商標）がある。導電材にはシート状のものがあり、例えばシート状の導電材として多層グラフェンがある。シート状の導電材は正極の断面において、糸状に見えることがある。 Typically, a carbon material or a metal material is used as the conductive material. The conductive material 553 is carbon black (furnace black, acetylene black, graphite, etc.). Most carbon blacks have a smaller particle size than the positive electrode active material 561. The conductive material 554 is carbon nanotubes (CNT) and VGCF (registered trademark). Some conductive materials are in sheet form, and an example of a sheet-like conductive material is multilayer graphene. A sheet-like conductive material may appear thread-like in the cross section of the positive electrode.
導電材５５３は正極活物質５６１等の隙間に入り込むことが可能であり、また凝集しやすい。そのため導電材５５３は近くに配置された正極活物質間の導電パスを補助することができる。導電材５５４は、折れ曲がった領域も有するが、正極活物質５６１等より大きなものとなる。そのため導電材５５４は、隣接した正極活物質間に加えて、離間又は離隔して配置された正極活物質間の導電パスを補助することもできる。このように導電材は二以上の形状のものを混合するとよい。 The conductive material 553 can enter the gaps between the positive electrode active material 561 and the like, and is also prone to agglomeration. Therefore, the conductive material 553 can assist the conductive path between the positive electrode active materials arranged nearby. The conductive material 554 also has a bent region, but is larger than the positive electrode active material 561 and the like. Therefore, the conductive material 554 can assist the conductive path between the positive electrode active materials arranged apart or at a distance, in addition to between adjacent positive electrode active materials. In this way, it is advisable to mix conductive materials of two or more shapes.
例えば導電材５５４として、シート状の導電助剤を用いてもよい。シート状の導電材として多層グラフェンを用い、粒子状の導電材としてカーボンブラックを用いた場合、これらが混合されたスラリーの状態で、カーボンブラックの重量がグラフェンの１．５倍以上２０倍以下、好ましくは２倍以上９．５倍以下の重量となるとよい。 For example, a sheet-like conductive additive may be used as the conductive material 554. When multilayer graphene is used as the sheet-like conductive material and carbon black is used as the particulate conductive material, the weight of the carbon black in the mixed slurry state is preferably 1.5 to 20 times, and more preferably 2 to 9.5 times, that of the graphene.
多層グラフェンとカーボンブラックの混合割合を上記範囲とすると、カーボンブラックが凝集せずに、分散しやすい。また、多層グラフェンとカーボンブラックの混合割合を上記範囲とすると、カーボンブラックのみを導電材に用いた場合よりも電極密度を高くすることができる。電極密度を高くすることで、単位重量当たりの容量を大きくすることができる。 When the mixing ratio of multi-layer graphene and carbon black is within the above range, the carbon black does not aggregate and is easily dispersed. Furthermore, when the mixing ratio of multi-layer graphene and carbon black is within the above range, the electrode density can be made higher than when only carbon black is used as the conductive material. By increasing the electrode density, the capacity per unit weight can be increased.
さらに多層グラフェンとカーボンブラックの混合割合を上記範囲とすることで、急速充電に対応することができる。 Furthermore, by keeping the mixing ratio of multi-layer graphene and carbon black within the above range, it is possible to support rapid charging.
［電解質］
電解質は、有機溶媒に電解質（リチウム塩）が溶解されたものであり、電解液と呼ぶこともできる。本明細書等において、電解質は、常温で液体である有機溶媒が含まれるものに限定されず、固体電解質を含む概念である。または、常温で液体である有機溶媒と、常温で固体である固体電解質の双方を含む電解質（半固体の電解質）も含む概念である。 [Electrolytes]
The electrolyte is an electrolyte (lithium salt) dissolved in an organic solvent, and can also be called an electrolytic solution. In this specification and the like, the electrolyte is not limited to an electrolyte that contains an organic solvent that is liquid at room temperature, but is a concept that includes a solid electrolyte. Alternatively, the electrolyte is a concept that includes an electrolyte (semi-solid electrolyte) that contains both an organic solvent that is liquid at room temperature and a solid electrolyte that is solid at room temperature.
＜常温で液体である有機溶媒＞
常温で液体である有機溶媒の一例について、以下に説明する。 <Organic solvents that are liquid at room temperature>
An example of an organic solvent that is liquid at room temperature will be described below.
常温で液体である有機溶媒は、非プロトン性有機溶媒が好ましく、例えば、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）、ブチレンカーボネート、クロロエチレンカーボネート、ビニレンカーボネート、γ−ブチロラクトン、γ−バレロラクトン、ジメチルカーボネート（ＤＭＣ）、ジエチルカーボネート（ＤＥＣ）、エチルメチルカーボネート（ＥＭＣ）、ギ酸メチル、酢酸メチル、酢酸エチル、プロピオン酸メチル、プロピオン酸エチル（ＥＰ）、プロピオン酸プロピル（ＰＰ）、酪酸メチル、１，３−ジオキサン、１，４−ジオキサン、ジメトキシエタン（ＤＭＥ）、ジメチルスルホキシド、ジエチルエーテル、メチルジグライム、アセトニトリル、ベンゾニトリル、テトラヒドロフラン、スルホラン、スルトン等の一種、又はこれらのうちの二種以上を任意の組み合わせ及び比率で用いることができる。 The organic solvent that is liquid at room temperature is preferably an aprotic organic solvent, and for example, one of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, chloroethylene carbonate, vinylene carbonate, γ-butyrolactone, γ-valerolactone, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate (EP), propyl propionate (PP), methyl butyrate, 1,3-dioxane, 1,4-dioxane, dimethoxyethane (DME), dimethyl sulfoxide, diethyl ether, methyl diglyme, acetonitrile, benzonitrile, tetrahydrofuran, sulfolane, sultone, etc., or two or more of these can be used in any combination and ratio.
常温で液体である有機溶媒として、難燃性及び難揮発性であるイオン液体（常温溶融塩）を一つ又は複数用いることで、電池セルの内部短絡又は過充電等によって内部温度が上昇しても、電池セルの破裂及び発火などを防ぐことができる。イオン液体は、カチオンとアニオンからなり、有機カチオンとアニオンとを含む。電解質に用いる有機カチオンとして、四級アンモニウムカチオン、三級スルホニウムカチオン、及び四級ホスホニウムカチオン等の脂肪族オニウムカチオン、又はイミダゾリウムカチオン及びピリジニウムカチオン等の芳香族カチオンが挙げられる。また、電解質に用いるアニオンとして、１価のアミド系アニオン、１価のメチド系アニオン、フルオロスルホン酸アニオン、パーフルオロアルキルスルホン酸アニオン、テトラフルオロボレートアニオン、パーフルオロアルキルボレートアニオン、ヘキサフルオロホスフェートアニオン、又はパーフルオロアルキルホスフェートアニオン等が挙げられる。 By using one or more flame-retardant and non-volatile ionic liquids (room-temperature molten salts) as an organic solvent that is liquid at room temperature, it is possible to prevent the battery cell from bursting or catching fire, even if the internal temperature rises due to an internal short circuit or overcharging of the battery cell. The ionic liquid is composed of a cation and an anion, and includes an organic cation and an anion. Examples of the organic cation used in the electrolyte include aliphatic onium cations such as quaternary ammonium cations, tertiary sulfonium cations, and quaternary phosphonium cations, and aromatic cations such as imidazolium cations and pyridinium cations. Examples of the anion used in the electrolyte include monovalent amide anions, monovalent methide anions, fluorosulfonate anions, perfluoroalkylsulfonate anions, tetrafluoroborate anions, perfluoroalkylborate anions, hexafluorophosphate anions, and perfluoroalkylphosphate anions.
また、上記有機溶媒に溶解させるリチウム塩としては、例えばＬｉＰＦ６、ＬｉＣｌＯ４、ＬｉＡｓＦ６、ＬｉＢＦ４、ＬｉＡｌＣｌ４、ＬｉＳＣＮ、ＬｉＢｒ、ＬｉＩ、Ｌｉ２ＳＯ４、Ｌｉ２Ｂ１０Ｃｌ１０、Ｌｉ２Ｂ１２Ｃｌ１２、ＬｉＣＦ３ＳＯ３、ＬｉＣ４Ｆ９ＳＯ３、ＬｉＣ（ＣＦ３ＳＯ２）３、ＬｉＣ（Ｃ２Ｆ５ＳＯ２）３、ＬｉＮ（ＣＦ３ＳＯ２）２、ＬｉＮ（Ｃ４Ｆ９ＳＯ２）（ＣＦ３ＳＯ２）、及びＬｉＮ（Ｃ２Ｆ５ＳＯ２）２等から選ばれた一又は二以上を用いることができる。 The lithium salt to be dissolved in the organic solvent may be, for example , one or more selected from LiPF6 , LiClO4 , LiAsF6 , LiBF4 , LiAlCl4 , LiSCN, LiBr , LiI, Li2SO4, Li2B10Cl10, Li2B12Cl12, LiCF3SO3, LiC4F9SO3, LiC(CF3SO2)3 , LiC ( C2F5SO2 ) 3 , LiN ( CF3SO2 ) 2 , LiN ( C4F9SO2 ) ( CF3SO2 ) , and LiN( C2F5SO2 ) 2 .
また上記有機溶媒は添加剤を有してもよい。例えば、添加剤としてビニレンカーボネート（ＶＣ）、プロパンスルトン（ＰＳ）、ＴｅｒＴ−ブチルベンゼン（ＴＢＢ）、フルオロエチレンカーボネート（ＦＥＣ）、リチウムビス（オキサレート）ボレート（ＬｉＢＯＢ）、またスクシノニトリル、アジポニトリル（ＡＤＮ）、又はエチレングリコールビス（プロピオ二トリル）エーテル（ＥＧＢＥ）等のニトリル化合物などを上記有機溶媒に添加してもよい。ニトリル化合物は二種以上添加することが好ましい。さらにフルオロベンゼンを上記有機溶媒に添加してもよい。添加剤の濃度は、例えば電解液全体に対して０．１ｗｔ％以上５ｗｔ％以下とすればよい。ＬｉＢＯＢは良好な被膜を形成しやすく、特に好ましい。ＶＣ又はＦＥＣは充放電時に負極に良好な被膜を形成しサイクル特性を向上させることができ好ましい。ＰＳ又はＥＧＢＥは充放電時に正極に良好な被膜を形成しサイクル特性を向上させることができ好ましい。ＦＢは正極及び負極への有機溶媒のぬれ性が向上するため好ましい。ニトリル化合物は、ニトリル基が正極及び負極に配向して、有機溶媒の酸化分解を阻害するため耐電圧性を向上させることができ好ましい。さらにニトリル化合物は、負極に銅を有する集電体を用いた場合、過放電の際に銅の溶解を防ぐことができ好ましい。 The organic solvent may also have an additive. For example, vinylene carbonate (VC), propane sultone (PS), tert-butylbenzene (TBB), fluoroethylene carbonate (FEC), lithium bis(oxalate)borate (LiBOB), or nitrile compounds such as succinonitrile, adiponitrile (ADN), or ethylene glycol bis(propionitrile)ether (EGBE) may be added to the organic solvent as an additive. It is preferable to add two or more nitrile compounds. Furthermore, fluorobenzene may be added to the organic solvent. The concentration of the additive may be, for example, 0.1 wt% to 5 wt% relative to the entire electrolyte. LiBOB is particularly preferable because it is easy to form a good coating. VC or FEC is preferable because it can form a good coating on the negative electrode during charging and discharging to improve the cycle characteristics. PS or EGBE is preferable because it can form a good coating on the positive electrode during charging and discharging to improve the cycle characteristics. FB is preferable because it improves the wettability of the organic solvent to the positive electrode and the negative electrode. Nitrile compounds are preferred because the nitrile groups are oriented toward the positive and negative electrodes, inhibiting the oxidative decomposition of organic solvents and improving voltage resistance. Furthermore, when a copper-containing current collector is used for the negative electrode, nitrile compounds are preferred because they can prevent copper from dissolving during overdischarge.
電解質は常温で液体である必要はなく、有機溶媒としてポリマーゲル電解質を用いてもよい。ポリマーゲル電解質を用いることで、漏液性等に対する安全性が高まる。また、電池セルの薄型化及び軽量化が可能である。 The electrolyte does not need to be liquid at room temperature, and a polymer gel electrolyte may be used as an organic solvent. Using a polymer gel electrolyte increases safety against leakage, etc. Also, it is possible to make the battery cell thinner and lighter.
ゲル化されるポリマーとして、シリコーンゲル、アクリルゲル、アクリロニトリルゲル、ポリエチレンオキサイド系ゲル、ポリプロピレンオキサイド系ゲル、フッ素系ポリマーのゲル等を用いることができる。 Polymers that can be gelled include silicone gel, acrylic gel, acrylonitrile gel, polyethylene oxide gel, polypropylene oxide gel, fluorine-based polymer gel, etc.
ポリマーとしては、例えばポリエチレンオキシド（ＰＥＯ）などのポリアルキレンオキシド構造を有するポリマー、ＰＶＤＦ、及びポリアクリロニトリル等、及びそれらを含む共重合体等を用いることができる。例えばＰＶＤＦとヘキサフルオロプロピレン（ＨＦＰ）の共重合体であるＰＶＤＦ−ＨＦＰを用いることができる。また、形成されるポリマーは、多孔質形状を有してもよい。 As the polymer, for example, a polymer having a polyalkylene oxide structure such as polyethylene oxide (PEO), PVDF, polyacrylonitrile, etc., and copolymers containing these can be used. For example, PVDF-HFP, which is a copolymer of PVDF and hexafluoropropylene (HFP), can be used. In addition, the polymer formed may have a porous shape.
電解質は常温で液体である必要はなく、固体電解質を用いてもよい。例えば、硫化物系固体電解質、酸化物系固体電解質、またはハロゲン化物系固体電解質等を用いることができる。また、ＰＥＯ（ポリエチレンオキシド）系等の高分子材料を有する固体電解質を用いることができる。固体電解質を用いる場合には、セパレータ及びスペーサの設置が不要となる。また、電池セルを固体化できるため、漏液のおそれがなくなり安全性が飛躍的に向上する。 The electrolyte does not need to be liquid at room temperature, and a solid electrolyte may be used. For example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a halide-based solid electrolyte may be used. A solid electrolyte having a polymer material such as PEO (polyethylene oxide) may also be used. When a solid electrolyte is used, the installation of a separator and spacer is not required. In addition, since the battery cell can be solidified, there is no risk of leakage, and safety is dramatically improved.
硫化物系固体電解質には、チオリシコン系（Ｌｉ１０ＧｅＰ２Ｓ１２、Ｌｉ３．２５Ｇｅ０．２５Ｐ０．７５Ｓ４等）、硫化物ガラス（７０Ｌｉ２Ｓ・３０Ｐ２Ｓ５３０Ｌｉ２Ｓ・２６Ｂ２Ｓ３・４４ＬｉＩ、６３Ｌｉ２Ｓ・３６ＳｉＳ２・１Ｌｉ３ＰＯ４、５７Ｌｉ２Ｓ・３８ＳｉＳ２・５Ｌｉ４ＳｉＯ４、５０Ｌｉ２Ｓ・５０ＧｅＳ２等）、硫化物結晶化ガラス（Ｌｉ７Ｐ３Ｓ１１、Ｌｉ３．２５Ｐ０．９５Ｓ４等）が含まれる。硫化物系固体電解質は、高い伝導度を有する材料がある、低い温度で合成可能、また比較的やわらかいため充放電を経ても導電経路が保たれやすい等の利点がある。 Sulfide -based solid electrolytes include thiolithium-based electrolytes ( Li10GeP2S12 , Li3.25Ge0.25P0.75S4 , etc. ) , sulfide glass ( 70Li2S.30P2S530Li2S.26B2S3.44LiI , 63Li2S.36SiS2.1Li3PO4 , 57Li2S.38SiS2.5Li4SiO4 , 50Li2S.50GeS2 , etc. ) , and sulfide crystallized glass ( Li7P3S11 , Li3.25P0.95S4 , etc. ) . Sulfide-based solid electrolytes have the advantages of being highly conductive, being able to be synthesized at low temperatures, and being relatively soft, which makes it easier to maintain conductive paths even after charging and discharging.
酸化物系固体電解質には、ペロブスカイト型結晶構造を有する材料（Ｌａ２／３−ｘＬｉ３ｘＴｉＯ３等）、ＮＡＳＩＣＯＮ型結晶構造を有する材料（Ｌｉ１＋ＸＡｌＸＴｉ２−Ｘ（ＰＯ４）３等）、ガーネット型結晶構造を有する材料（Ｌｉ７Ｌａ３Ｚｒ２Ｏ１２等）、ＬＩＳＩＣＯＮ型結晶構造を有する材料（Ｌｉ１４ＺｎＧｅ４Ｏ１６等）、ＬＬＺＯ（Ｌｉ７Ｌａ３Ｚｒ２Ｏ１２）、酸化物ガラス（Ｌｉ３ＰＯ４−Ｌｉ４ＳｉＯ４、５０Ｌｉ４ＳｉＯ４・５０Ｌｉ３ＢＯ３等）、酸化物結晶化ガラス（Ｌｉ１．０７Ａｌ０．６９Ｔｉ１．４６（ＰＯ４）３、Ｌｉ１．５Ａｌ０．５Ｇｅ１．５（ＰＯ４）３等）が含まれる。酸化物系固体電解質は、大気中で安定であるといった利点がある。 Examples of oxide-based solid electrolytes include materials having a perovskite crystal structure (La2 /3- xLi3xTiO3 , etc.), materials having a NASICON crystal structure (Li1 + xAlxTi2 -x ( PO4 ) 3 , etc.), materials having a garnet crystal structure ( Li7La3Zr2O12 , etc. ), materials having a LISICON crystal structure ( Li14ZnGe4O16 , etc.), LLZO ( Li7La3Zr2O12 ), oxide glass ( Li3PO4 - Li4SiO4 , 50Li4SiO4.50Li3BO3 , etc. ) , oxide crystallized glass (Li1.07Al0.69Ti1.46 ( PO4 ) 3 , etc.), and oxide - based solid electrolytes . , Li1.5Al0.5Ge1.5 ( PO4 ) 3 , etc. Oxide - based solid electrolytes have the advantage of being stable in the air.
ハロゲン化物系固体電解質には、ＬｉＡｌＣｌ４、Ｌｉ３ＩｎＢｒ６、ＬｉＦ、ＬｉＣｌ、ＬｉＢｒ、ＬｉＩ等が含まれる。また、これらハロゲン化物系固体電解質を、ポーラス酸化アルミニウム又はポーラスシリカの細孔に充填したコンポジット材料も固体電解質として用いることができる。 Halide-based solid electrolytes include LiAlCl 4 , Li 3 InBr 6 , LiF, LiCl, LiBr, LiI, etc. Composite materials in which these halide-based solid electrolytes are filled into the pores of porous aluminum oxide or porous silica can also be used as solid electrolytes.
また、異なる固体電解質を混合して用いてもよい。 Different solid electrolytes may also be mixed and used.
中でも、ＮＡＳＩＣＯＮ型結晶構造を有するＬｉ１＋ｘＡｌｘＴｉ２−ｘ（ＰＯ４）３（０＜ｘ＜１）（以下、ＬＡＴＰ）は、アルミニウムとチタンという、本発明の一態様に用いる正極活物質の主原料又は添加元素と同一元素を含むため、サイクル特性の向上について相乗効果が期待でき好ましい。また、工程の削減による生産性の向上も期待できる。なお本明細書等において、ＮＡＳＩＣＯＮ型結晶構造とは、Ｍ２（ＡＯ４）３（Ｍ：遷移金属、Ａ：Ｓ、Ｐ、Ａｓ、Ｍｏ、Ｗ等）で表される化合物であり、ＭＯ６八面体とＡＯ４四面体が頂点を共有して３次元的に配列した構造を有するものをいう。 Among them, Li1 + xAlxTi2 -x ( PO4 ) 3 (0<x<1) (hereinafter referred to as LATP) having a NASICON type crystal structure is preferable because it contains the same elements as the main raw materials or additive elements of the positive electrode active material used in one embodiment of the present invention, that is, aluminum and titanium, and therefore is expected to have a synergistic effect on improving cycle characteristics. In addition, it is expected to improve productivity by reducing the number of steps. In this specification, the NASICON type crystal structure refers to a compound represented by M2 ( AO4 ) 3 (M: transition metal, A: S, P, As, Mo, W, etc.), which has a structure in which MO6 octahedrons and AO4 tetrahedrons are arranged three-dimensionally with vertices shared.
＜低温用に好ましい電解質の例＞
低温用に好ましい電解質（以下低温用電解質と記す）の一例について、以下に説明する。 <Examples of electrolytes preferred for low temperature use>
An example of an electrolyte suitable for low temperature use (hereinafter referred to as low temperature electrolyte) will be described below.
低温用電解質の有機溶媒は、エチレンカーボネート（ＥＣ）と、エチルメチルカーボネート（ＥＭＣ）と、ジメチルカーボネート（ＤＭＣ）と、を含み、前記エチレンカーボネート、前記エチルメチルカーボネート、及び前記ジメチルカーボネートの全含有量を１００ｖｏｌ％としたとき、前記エチレンカーボネート、前記エチルメチルカーボネート、及び前記ジメチルカーボネートの体積比が、ｘ：ｙ：１００−ｘ−ｙ（ただし、５≦ｘ≦３５であり、０＜ｙ＜６５である。）であるものを用いることができる。より具体的には、ＥＣと、ＥＭＣと、ＤＭＣと、を、ＥＣ：ＥＭＣ：ＤＭＣ＝３０：３５：３５（体積比）で含んだ有機溶媒を用いることができる。なお、上記の体積比は、電解液の混合前における体積比であってもよく、電解液を混合する際の外気は室温（代表的には、２５℃）であってもよい。 The organic solvent for the low-temperature electrolyte contains ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC), and when the total content of the ethylene carbonate, the ethyl methyl carbonate, and the dimethyl carbonate is 100 vol%, the volume ratio of the ethylene carbonate, the ethyl methyl carbonate, and the dimethyl carbonate is x:y:100-x-y (where 5≦x≦35 and 0<y<65). More specifically, an organic solvent containing EC, EMC, and DMC in a ratio of EC:EMC:DMC=30:35:35 (volume ratio) can be used. The above volume ratio may be the volume ratio before mixing with the electrolyte, and the outside air when mixing the electrolyte may be room temperature (typically 25° C.).
ＥＣは、環状カーボネートであり、高い比誘電率を有するため、リチウム塩の解離を促進させる効果を有する。一方で、ＥＣは、粘度が高く、凝固点（融点）が３８℃と高いため、有機溶媒としてＥＣ単体を用いた場合、低温環境下での使用が難しい。そこで、本発明の一態様として具体的に説明する有機溶媒は、ＥＣ単体ではなく、ＥＭＣとＤＭＣを更に含む。ＥＭＣは、鎖状カーボネートであり、電界液の粘度を下げる効果を有する上に、凝固点が−５４℃である。また、ＤＭＣも、鎖状カーボネートであり、電界液の粘度を下げる効果を有する上に、凝固点が−４３℃である。このような物性を有するＥＣ、ＥＭＣ、及びＤＭＣを、これら３つの有機溶媒の全含有量を１００ｖｏｌ％として、２５℃での体積比が、ｘ：ｙ：１００−ｘ−ｙ（ただし、５≦ｘ≦３５であり、０＜ｙ＜６５である。）となるように混合した有機溶媒を用いて作製された電解質は、凝固点が−４０℃以下という特徴を有する。 EC is a cyclic carbonate and has a high relative dielectric constant, which has the effect of promoting the dissociation of lithium salts. On the other hand, EC has a high viscosity and a high freezing point (melting point) of 38°C, so when EC alone is used as an organic solvent, it is difficult to use it in a low-temperature environment. Therefore, the organic solvent specifically described as one aspect of the present invention is not EC alone, but further contains EMC and DMC. EMC is a chain carbonate, has the effect of reducing the viscosity of the electrolyte, and has a freezing point of -54°C. DMC is also a chain carbonate, has the effect of reducing the viscosity of the electrolyte, and has a freezing point of -43°C. An electrolyte prepared using an organic solvent in which EC, EMC, and DMC having such physical properties are mixed so that the volume ratio at 25°C is x:y:100-x-y (where 5≦x≦35 and 0<y<65) when the total content of these three organic solvents is 100 vol%, has the characteristic of having a freezing point of -40°C or less.
電池セルに用いられている一般的な電解質は、−２０℃程度で凝固してしまうため、−４０℃で充放電できる電池を作製することは困難である。低温用電解質の有機溶媒として説明した上記電解質は、凝固点が−４０℃以下であるため、−４０℃という極低温環境下においても充放電可能な電池セルを実現できる。 General electrolytes used in battery cells freeze at around -20°C, making it difficult to create batteries that can be charged and discharged at -40°C. The electrolyte described above as an organic solvent for low-temperature electrolytes has a freezing point of -40°C or lower, making it possible to create battery cells that can be charged and discharged even in extremely low-temperature environments such as -40°C.
また、低温用電解質の有機溶媒に溶解させるリチウム塩は、上述のリチウム塩から選択できる。 The lithium salt dissolved in the organic solvent of the low-temperature electrolyte can be selected from the lithium salts described above.
また低温用電解質の有機溶媒が有する添加剤は、上述の添加剤から選択できる。 Additives contained in the organic solvent of the low-temperature electrolyte can be selected from the additives mentioned above.
［負極］
単電池は負極を有する。負極は、負極活物質層及び負極集電体を有する。また、負極活物質層は負極活物質を有し、さらに導電助剤及びバインダを有していてもよい。 [Negative electrode]
The unit cell has a negative electrode. The negative electrode has a negative electrode active material layer and a negative electrode current collector. The negative electrode active material layer has a negative electrode active material, and may further have a conductive assistant and a binder.
［負極集電体］
負極は負極集電体を有する。負極集電体には、正極集電体と同様の材料を用いることができる。 [Negative electrode current collector]
The negative electrode has a negative electrode current collector. The negative electrode current collector can be made of the same material as the positive electrode current collector.
［負極活物質］
負極は負極活物質を有する。負極活物質としては、例えば合金材料又は炭素材料を用いることができる。 [Negative electrode active material]
The negative electrode includes a negative electrode active material, which may be, for example, an alloy material or a carbon material.
また、負極活物質は、リチウムとの合金化・脱合金化反応により充放電反応を行うことが可能な元素を用いることができる。例えば、シリコン、スズ、ガリウム、アルミニウム、ゲルマニウム、鉛、アンチモン、ビスマス、銀、亜鉛、カドミウム、インジウム等のうち少なくとも一つを含む材料を用いることができる。このような元素は炭素と比べて容量が大きく、特にシリコンは理論容量が４２００ｍＡｈ／ｇと高い。このため、負極活物質にシリコンを用いることが好ましい。また、これらの元素を有する化合物を用いてもよい。例えば、ＳｉＯ、Ｍｇ２Ｓｉ、Ｍｇ２Ｇｅ、ＳｎＯ、ＳｎＯ２、Ｍｇ２Ｓｎ、ＳｎＳ２、Ｖ２Ｓｎ３、ＦｅＳｎ２、ＣｏＳｎ２、Ｎｉ３Ｓｎ２、Ｃｕ６Ｓｎ５、Ａｇ３Ｓｎ、Ａｇ３Ｓｂ、Ｎｉ２ＭｎＳｂ、ＣｅＳｂ３、ＬａＳｎ３、Ｌａ３Ｃｏ２Ｓｎ７、ＣｏＳｂ３、ＩｎＳｂ、ＳｂＳｎ等がある。ここで、リチウムとの合金化・脱合金化反応により充放電反応を行うことが可能な元素、及び該元素を有する化合物等を合金材料と呼ぶ場合がある。 In addition, the negative electrode active material can be an element capable of performing a charge/discharge reaction by alloying/dealloying reaction with lithium. For example, a material containing at least one of silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, indium, etc. can be used. Such elements have a larger capacity than carbon, and silicon in particular has a high theoretical capacity of 4200 mAh/g. For this reason, it is preferable to use silicon as the negative electrode active material. Compounds containing these elements may also be used. Examples include SiO, Mg2Si , Mg2Ge , SnO, SnO2 , Mg2Sn , SnS2 , V2Sn3 , FeSn2 , CoSn2 , Ni3Sn2 , Cu6Sn5 , Ag3Sn, Ag3Sb, Ni2MnSb, CeSb3, LaSn3, La3Co2Sn7 , CoSb3 , InSb , SbSn , etc. Here, elements capable of carrying out charge/discharge reactions by alloying/dealloying reactions with lithium, and compounds containing such elements, may be referred to as alloying materials.
本明細書等において、「ＳｉＯ」は例えば一酸化シリコンを指す。あるいはＳｉＯは、ＳｉＯｘと表すこともできる。ここでｘは１又は１近傍の値を有することが好ましい。例えばｘは、０．２以上１．５以下が好ましく、０．３以上１．２以下が好ましい。 In this specification and the like, "SiO" refers to, for example, silicon monoxide. Alternatively, SiO can be expressed as SiO x . Here, x preferably has a value of 1 or close to 1. For example, x is preferably 0.2 or more and 1.5 or less, and more preferably 0.3 or more and 1.2 or less.
炭素材料は、黒鉛、易黒鉛化性炭素（ソフトカーボン）、難黒鉛化性炭素（ハードカーボン）、炭素繊維（カーボンナノチューブ）、グラフェン、カーボンブラック等を用いればよい。 The carbon material may be graphite, easily graphitizable carbon (soft carbon), non-graphitizable carbon (hard carbon), carbon fiber (carbon nanotube), graphene, carbon black, etc.
黒鉛は、人造黒鉛又は天然黒鉛等が挙げられる。人造黒鉛としては例えば、メソカーボンマイクロビーズ（ＭＣＭＢ）、コークス系人造黒鉛、ピッチ系人造黒鉛等が挙げられる。さらに人造黒鉛として、球状の形状を有する球状黒鉛を用いることができる。例えば、ＭＣＭＢは球状の形状を有する場合があり、好ましい。また、ＭＣＭＢはその表面積を小さくすることが比較的容易であり、好ましい場合がある。天然黒鉛としては、例えば、鱗片状黒鉛、球状化天然黒鉛等が挙げられる。 Examples of graphite include artificial graphite and natural graphite. Examples of artificial graphite include mesocarbon microbeads (MCMB), coke-based artificial graphite, and pitch-based artificial graphite. Furthermore, as the artificial graphite, spherical graphite having a spherical shape can be used. For example, MCMB may have a spherical shape, which is preferable. In addition, it is relatively easy to reduce the surface area of MCMB, which may be preferable. Examples of natural graphite include flake graphite and spherical natural graphite.
黒鉛は、リチウムイオンが黒鉛に挿入されたとき（リチウム−黒鉛層間化合物の生成時）にリチウム金属と同程度に低い電位を示す（０．０５Ｖ以上０．３Ｖ以下　ｖｓ．Ｌｉ／Ｌｉ＋）。これにより、黒鉛を用いたリチウムイオン電池は高い作動電圧を示すことができる。さらに、黒鉛は、単位体積当たりの容量が比較的高い、体積膨張が比較的小さい、安価である、リチウム金属に比べて安全性が高い等の利点を有するため、好ましい。 When lithium ions are inserted into graphite (when a lithium-graphite intercalation compound is formed), graphite exhibits a low potential (0.05 V to 0.3 V vs. Li/Li + ) similar to that of lithium metal. This allows lithium ion batteries using graphite to exhibit a high operating voltage. Furthermore, graphite is preferable because it has the advantages of a relatively high capacity per unit volume, a relatively small volume expansion, low cost, and higher safety than lithium metal.
また、負極活物質として、二酸化チタン（ＴｉＯ２）、リチウムチタン酸化物（Ｌｉ４Ｔｉ５Ｏ１２）、リチウム−黒鉛層間化合物（ＬｉｘＣ６）、五酸化ニオブ（Ｎｂ２Ｏ５）、二酸化タングステン（ＷＯ２）、二酸化モリブデン（ＭｏＯ２）等の酸化物を用いることができる。 In addition, oxides such as titanium dioxide ( TiO2 ) , lithium titanium oxide ( Li4Ti5O12 ), lithium-graphite intercalation compound ( LixC6 ), niobium pentoxide ( Nb2O5 ), tungsten dioxide ( WO2 ), and molybdenum dioxide ( MoO2 ) can be used as the negative electrode active material.
また、負極活物質として、リチウムと遷移金属の窒化物である、Ｌｉ３Ｎ型構造をもつＬｉ３−ｘＭｘＮ（Ｍ＝Ｃｏ、Ｎｉ、Ｃｕ）を用いることができる。例えば、Ｌｉ２．６Ｃｏ０．４Ｎは大きな放電容量（活物質重量当たり９００ｍＡｈ／ｇ、１８９０ｍＡｈ／ｃｍ３）を示し好ましい。 As the negative electrode active material, Li3 - xMxN (M = Co, Ni, Cu) having a Li3N type structure, which is a nitride of lithium and a transition metal , can be used. For example, Li2.6Co0.4N is preferable because it shows a large discharge capacity (900mAh/g, 1890mAh/ cm3 per active material weight).
リチウムと遷移金属の窒化物を用いると、負極活物質中にリチウムイオンを含むため、正極活物質としてリチウムイオンを含まない上記Ｖ２Ｏ５、Ｃｒ３Ｏ８等の材料と組み合わせることができ好ましい。なお、正極活物質にリチウムイオンを含む材料を用いる場合でも、予め正極活物質に含まれるリチウムイオンを脱離させることで、負極活物質としてリチウムと遷移金属の窒化物を用いることができる。 When a nitride of lithium and a transition metal is used, lithium ions are contained in the negative electrode active material, and therefore it is preferable that the nitride of lithium and a transition metal is combined with a material not containing lithium ions as a positive electrode active material, such as V 2 O 5 or Cr 3 O 8. Even when a material containing lithium ions is used as the positive electrode active material, the nitride of lithium and a transition metal can be used as the negative electrode active material by desorbing the lithium ions contained in the positive electrode active material in advance.
また、コンバージョン反応が生じる材料を負極活物質として用いることもできる。例えば、酸化コバルト（ＣｏＯ）、酸化ニッケル（ＮｉＯ）、酸化鉄（ＦｅＯ）等の、リチウムとの合金を作らない遷移金属酸化物を負極活物質に用いてもよい。コンバージョン反応が生じる材料としては、さらに、Ｆｅ２Ｏ３、ＣｕＯ、Ｃｕ２Ｏ、ＲｕＯ２、Ｃｒ２Ｏ３等の酸化物、ＣｏＳ０．８９、ＮｉＳ、ＣｕＳ等の硫化物、Ｚｎ３Ｎ２、Ｃｕ３Ｎ、Ｇｅ３Ｎ４等の窒化物、ＮｉＰ２、ＦｅＰ２、ＣｏＰ３等のリン化物、ＦｅＦ３、ＢｉＦ３等のフッ化物でも起こる。 Also, materials that undergo conversion reactions can be used as negative electrode active materials. For example, transition metal oxides that do not form an alloy with lithium, such as cobalt oxide (CoO), nickel oxide (NiO), and iron oxide (FeO), may be used as negative electrode active materials. Materials that undergo conversion reactions include oxides such as Fe2O3 , CuO, Cu2O , RuO2 , and Cr2O3 , sulfides such as CoS0.89 , NiS , and CuS, nitrides such as Zn3N2 , Cu3N , and Ge3N4 , phosphides such as NiP2 , FeP2 , and CoP3 , and fluorides such as FeF3 and BiF3 .
負極活物質層が有することのできる導電材及びバインダとしては、正極活物質層が有することのできる導電材及びバインダと同様の材料を用いることができる。 The conductive material and binder that can be used in the negative electrode active material layer can be the same materials as the conductive material and binder that can be used in the positive electrode active material layer.
また、本発明の負極の別の形態として、負極活物質を有さない負極を用いることができる。負極活物質を有さない負極を用いた電池セルでは、充電時において負極集電体上にリチウムが析出し、放電時において該負極集電体上のリチウムが溶出することができる。そのため、完全放電状態以外においては、負極集電体上にリチウムを有する形態となる。 As another embodiment of the negative electrode of the present invention, a negative electrode having no negative electrode active material can be used. In a battery cell using a negative electrode having no negative electrode active material, lithium is deposited on the negative electrode current collector during charging, and the lithium on the negative electrode current collector can be dissolved during discharging. Therefore, except in a fully discharged state, the negative electrode has lithium on the negative electrode current collector.
負極活物質を有さない負極を用いる場合、負極集電体上にリチウムの析出を均一化するための膜を有してもよい。リチウムの析出を均一化するための膜として、例えばリチウムイオン伝導性を有する固体電解質を用いることができる。固体電解質として、硫化物系固体電解質、酸化物系固体電解質、及び高分子系固体電解質などを用いることができる。なかでも、高分子系固体電解質は負極集電体上に均一に膜形成することが比較的容易であるため、リチウムの析出を均一化するための膜として好適である。 When a negative electrode that does not have a negative electrode active material is used, a film for uniformly depositing lithium may be provided on the negative electrode current collector. As the film for uniformly depositing lithium, for example, a solid electrolyte having lithium ion conductivity can be used. As the solid electrolyte, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a polymer-based solid electrolyte, etc. can be used. Among them, a polymer-based solid electrolyte is suitable as a film for uniformly depositing lithium, since it is relatively easy to form a uniform film on the negative electrode current collector.
また、負極活物質を有さない負極を用いる場合、凹凸を有する負極集電体を用いることができる。凹凸を有する負極集電体を用いる場合、負極集電体の凹部は負極集電体が有するリチウムが析出し易い空洞となるため、リチウムが析出する際に、デンドライト状の形状となることを抑制することができる。 In addition, when using a negative electrode that does not have a negative electrode active material, a negative electrode current collector with irregularities can be used. When using a negative electrode current collector with irregularities, the concaves of the negative electrode current collector become cavities into which the lithium contained in the negative electrode current collector is likely to precipitate, so that it is possible to prevent the lithium from forming a dendritic shape when it precipitates.
［導電材］
負極は導電材を有する。負極が有する導電材は上述した正極の導電材から選択することができる。負極の導電材は、正極の導電材と異なっていてもよい。 [Conductive material]
The negative electrode has a conductive material which can be selected from the conductive materials of the positive electrode described above. The conductive material of the negative electrode can be different from the conductive material of the positive electrode.
［セパレータ］
電池セルは、正極と負極の間に配置されたセパレータを有する。セパレータは正極と負極の間を絶縁している。セパレータは電解質に対して安定であり、保液性に優れた材料を用いることが好ましい。セパレータとしては、例えば、紙をはじめとするセルロースを有する繊維、不織布、ガラス繊維、セラミックス、或いはナイロン（ポリアミド）、ビニロン（ポリビニルアルコール系繊維）、ポリエステル、ポリイミド、アクリル、ポリオレフィン、ポリウレタンを用いた合成繊維等で形成されたものを用いることができる。 [Separator]
The battery cell has a separator disposed between the positive electrode and the negative electrode. The separator insulates the positive electrode from the negative electrode. It is preferable that the separator is made of a material that is stable against the electrolyte and has excellent liquid retention. The separator may be made of, for example, paper or other cellulose-containing fibers, nonwoven fabrics, glass fibers, ceramics, or synthetic fibers made of nylon (polyamide), vinylon (polyvinyl alcohol-based fibers), polyester, polyimide, acrylic, polyolefin, or polyurethane.
セパレータは空孔率３０％以上８５％以下、好ましくは４５％以上６５％以下であると好ましい。空孔率が大きいと電解質が含浸されやすく好ましい。セパレータの空孔率は正極側と負極側とで異ならせてもよく、正極側の空孔率が負極側の空孔率よりも高いと好ましい。空孔率を異ならせるには、同一材料に対して空孔率を異ならせる構成、又は空孔率の異なる異種材料を用いる構成がある。異種材料を用いる場合、これらを積層させることでセパレータの空孔率を異ならせることができる。 The separator preferably has a porosity of 30% to 85%, preferably 45% to 65%. A high porosity is preferable because it is easier for the electrolyte to be impregnated. The porosity of the separator may be different between the positive electrode side and the negative electrode side, and it is preferable that the porosity on the positive electrode side is higher than the porosity on the negative electrode side. To make the porosity different, the same material may be made to have different porosities, or different materials with different porosities may be used. When different materials are used, the porosity of the separator can be made different by stacking them.
セパレータの厚みは、５μｍ以上２００μｍ以下、好ましくは５μｍ以上１００μｍ以下がよい。 The thickness of the separator should be 5 μm or more and 200 μm or less, preferably 5 μm or more and 100 μm or less.
セパレータは、平均孔径４０ｎｍ以上３μｍ以下、好ましくは７０ｎｍ以上１μｍ以下であると好ましい。平均孔径が大きいと、キャリアイオンしやすく好ましい。セパレータの平均孔径は正極側と負極側とで異なってもよく、正極側の平均孔径が負極側の平均孔径よりも大きいと好ましい。平均孔径を異ならせるには、同一材料に対して平均孔径を異ならせる構成、又は平均孔径の異なる異種材料を用いる構成がある。異種材料を用いる場合、これらを積層させることでセパレータの平均孔径を異ならせることができる。 The separator preferably has an average pore size of 40 nm to 3 μm, more preferably 70 nm to 1 μm. A larger average pore size is preferable because it facilitates carrier ion generation. The average pore size of the separator may be different between the positive electrode side and the negative electrode side, and it is preferable that the average pore size on the positive electrode side is larger than the average pore size on the negative electrode side. To make the average pore size different, the same material may be used with different average pore sizes, or different materials with different average pore sizes may be used. When different materials are used, the average pore size of the separator can be made different by stacking them.
セパレータの耐熱性は２００℃以上が好ましい。 The separator should preferably have a heat resistance of 200°C or higher.
ポリイミドを用いたセパレータであって、１０μｍ以上５０μｍ以下の厚みを有し、空孔率が７５％以上８５％以下のものを用いると、電池セルの出力特性が向上するため好ましい。 It is preferable to use a separator made of polyimide that has a thickness of 10 μm or more and 50 μm or less and a porosity of 75% or more and 85% or less, as this improves the output characteristics of the battery cell.
セパレータは袋状に加工し、正極又は負極のいずれか一方を包む又は挟むように袋状のセパレータを配置してもよい。 The separator may be processed into a bag shape and the bag-shaped separator may be arranged to wrap or sandwich either the positive electrode or the negative electrode.
セパレータ全体の膜厚は１μｍ以上１００μｍ以下が好ましく、膜厚の範囲内であれば、セパレータは単層構造又は多層構造のいずれでもよい。多層構造の場合、ポリプロピレン、ポリエチレン等の有機材料フィルムに、セラミックス系材料、フッ素系材料、ポリアミド系材料、又はこれらを混合したもの等をコートしたものを用いることができる。セラミックス系材料としては、例えば酸化アルミニウム粒子、又は酸化シリコン粒子等を用いることができる。フッ素系材料としては、例えばＰＶＤＦ、又はポリテトラフルオロエチレン等を用いることができる。ポリアミド系材料としては、例えばナイロン、又はアラミド（メタ系アラミド、パラ系アラミド）等を用いることができる。 The thickness of the entire separator is preferably 1 μm or more and 100 μm or less, and within the thickness range, the separator may have either a single-layer structure or a multi-layer structure. In the case of a multi-layer structure, an organic material film such as polypropylene or polyethylene coated with a ceramic material, a fluorine material, a polyamide material, or a mixture of these can be used. As the ceramic material, for example, aluminum oxide particles or silicon oxide particles can be used. As the fluorine material, for example, PVDF or polytetrafluoroethylene can be used. As the polyamide material, for example, nylon or aramid (meta-aramid, para-aramid) can be used.
セラミックス系材料をセパレータの表面にコートすると耐酸化性が向上するため、高電圧充放電の際のセパレータの劣化を抑制し、電池セルの信頼性を向上させることができる。またフッ素系材料をセパレータの表面にコートするとセパレータと電極が密着しやすくなり、出力特性を向上させることができる。ポリアミド系材料、特にアラミドをセパレータの表面にコートすると、耐熱性が向上するため、電池セルの安全性を向上させることができる。 Coating the separator surface with a ceramic material improves oxidation resistance, suppressing the separator's deterioration during high-voltage charging and discharging and improving the reliability of the battery cell. Coating the separator surface with a fluorine-based material also makes it easier for the separator and electrodes to adhere to each other, improving output characteristics. Coating the separator surface with a polyamide-based material, especially aramid, improves heat resistance, improving the safety of the battery cell.
例えばポリプロピレンのフィルムの両面に酸化アルミニウムとアラミドの混合材料をコートしてもよい。また、ポリプロピレンのフィルムの、正極と接する面に酸化アルミニウムとアラミドの混合材料をコートし、負極と接する面にフッ素系材料をコートしてもよい。 For example, both sides of a polypropylene film may be coated with a mixture of aluminum oxide and aramid. Alternatively, the surface of the polypropylene film that comes into contact with the positive electrode may be coated with a mixture of aluminum oxide and aramid, and the surface that comes into contact with the negative electrode may be coated with a fluorine-based material.
このような多層構造のセパレータを用いると、各材料の機能をセパレータに持たせることができるため、セパレータ全体としての厚さが薄い場合でも、正極と負極との絶縁を確保でき電池セルの安全性を保つことができる。そのため、電池セルの体積あたりの容量を大きくすることができ好ましい。 By using such a multi-layered separator, the functions of each material can be imparted to the separator, so even if the separator as a whole is thin, insulation between the positive and negative electrodes can be ensured and the safety of the battery cell can be maintained. This is preferable because it allows the capacity per volume of the battery cell to be increased.
［外装体］
単電池は外装体を有する。外装体としては、例えばアルミニウムなどの金属材料又は樹脂材料を用いることができる。また、フィルム状の外装体を用いることもできる。フィルムとしては、例えばポリエチレン、ポリプロピレン、ポリカーボネート、アイオノマー、ポリアミド等の材料からなる膜上に、アルミニウム、ステンレス、銅、ニッケル等の可撓性に優れた金属薄膜を設け、さらに該金属薄膜上に外装体の外面としてポリアミド系樹脂、ポリエステル系樹脂等の絶縁性合成樹脂膜を設けた三層構造のフィルムを用いることができる。 [Exterior body]
The unit cell has an exterior body. For example, a metal material such as aluminum or a resin material can be used as the exterior body. Also, a film-shaped exterior body can be used. For example, a three-layer structure film can be used in which a thin metal film having excellent flexibility such as aluminum, stainless steel, copper, nickel, etc. is provided on a film made of a material such as polyethylene, polypropylene, polycarbonate, ionomer, polyamide, etc., and an insulating synthetic resin film such as a polyamide-based resin or polyester-based resin is further provided on the thin metal film as the outer surface of the exterior body.
以上のとおり、本実施の形態では、単電池の構成等について例示したが、上記の例示に限定解釈されるものではない。 As described above, in this embodiment, the configuration of the single cell is illustrated, but the interpretation is not limited to the above example.
本実施の形態は、他の実施の形態と適宜組み合わせて用いることができる。 This embodiment can be used in appropriate combination with other embodiments.
（実施の形態３）
本実施の形態では、上記実施の形態に適用できる正極活物質の製造方法１について説明する。具体的には正極活物質を共沈法により製造する方法について、図１４等を用いて説明する。本実施の形態で示す正極活物質の製造方法１は、断りのない限り、第１のバッテリ１０１ａ、及び／又は第２のバッテリ１０１ｂに適用できる。 (Embodiment 3)
In this embodiment, a method for manufacturing a positive electrode active material 1 that can be applied to the above-mentioned embodiment will be described. Specifically, a method for manufacturing a positive electrode active material by a coprecipitation method will be described with reference to FIG. 14 and the like. Unless otherwise specified, the method for manufacturing a positive electrode active material 1 shown in this embodiment can be applied to the first battery 101a and/or the second battery 101b.
［正極活物質の製造方法１］
＜遷移金属Ｍ源＞
図１４に示す遷移金属Ｍ源８１（図面ではＭ源と記す）について説明する。遷移金属Ｍとしては、例えば、ニッケル、コバルト、マンガンのうち少なくとも一を用いることができる。例えば、遷移金属Ｍとしては、ニッケルのみを用いる場合、コバルトとマンガンの二種を用いる場合、ニッケルとコバルトの二種を用いる場合、又は、ニッケル、コバルト、マンガンの三種を用いる場合がある。 [Method of manufacturing positive electrode active material 1]
<Transition Metal M Source>
A transition metal M source 81 (referred to as M source in the drawing) shown in Fig. 14 will be described. As the transition metal M, for example, at least one of nickel, cobalt, and manganese can be used. For example, as the transition metal M, there is a case where only nickel is used, a case where two types of cobalt and manganese are used, a case where two types of nickel and cobalt are used, or a case where three types of nickel, cobalt, and manganese are used.
ニッケル、コバルト、及びマンガンを用いる場合、層状岩塩型の結晶構造をとりうる範囲のニッケル、コバルト、及びマンガンの混合比とすることが好ましい。 When nickel, cobalt, and manganese are used, it is preferable to mix nickel, cobalt, and manganese in a ratio that allows a layered rock salt type crystal structure to be formed.
特に遷移金属Ｍとしてニッケルを多く含むと、コバルトが多い場合と比較して原料が安価になる場合があり、また重量あたりの放電容量が増加する場合があり好ましい。このような活物質は電気自動車に好適である。例えば遷移金属Ｍのうちニッケルは、２５ａｔｏｍｉｃ％を超えることが好ましく、６０ａｔｏｍｉｃ％以上がより好ましく、８０ａｔｏｍｉｃ％以上がさらに好ましい。しかしニッケルの占める割合が高すぎると、化学安定性及び耐熱性が下がるおそれがある。そのため遷移金属Ｍのうちニッケルは９５ａｔｏｍｉｃ％以下であることが好ましい。 In particular, if the transition metal M contains a large amount of nickel, the raw material may be cheaper than when the transition metal M contains a large amount of cobalt, and the discharge capacity per weight may increase, which is preferable. Such an active material is suitable for electric vehicles. For example, the nickel content of the transition metal M is preferably more than 25 atomic%, more preferably 60 atomic% or more, and even more preferably 80 atomic% or more. However, if the proportion of nickel is too high, there is a risk of reduced chemical stability and heat resistance. Therefore, it is preferable that the nickel content of the transition metal M is 95 atomic% or less.
遷移金属Ｍとしてコバルトを有すると、平均放電電圧が高く、またコバルトが層状岩塩型の構造を安定化に寄与するため信頼性の高い電池セルとすることができ好ましい。このような活物質は電気自動車に好適である。 When cobalt is used as the transition metal M, the average discharge voltage is high, and since cobalt contributes to stabilizing the layered rock-salt structure, it is possible to form a highly reliable battery cell, which is preferable. Such an active material is suitable for electric vehicles.
しかしコバルトは価格がニッケル及びマンガンよりも高く、不安定であるため、コバルトの占める割合が高すぎると、製造のコストが増大するおそれがある。そのため例えば遷移金属Ｍのうちコバルトは、２．５ａｔｏｍｉｃ％以上３４ａｔｏｍｉｃ％以下であることが好ましい。なお遷移金属Ｍとして、必ずしもコバルトを含まなくてもよい。 However, since cobalt is more expensive than nickel and manganese and is unstable, if the proportion of cobalt is too high, there is a risk of increased manufacturing costs. Therefore, for example, it is preferable that the cobalt content of the transition metal M is 2.5 atomic % or more and 34 atomic % or less. Note that the transition metal M does not necessarily have to contain cobalt.
遷移金属Ｍとしてマンガンを有すると、耐熱性及び化学安定性が向上するため好ましい。このような活物質は電気自動車に好適である。 It is preferable to have manganese as the transition metal M, as this improves heat resistance and chemical stability. Such active materials are suitable for electric vehicles.
しかしマンガンの占める割合が高すぎると、放電電圧及び放電容量が低下する傾向がある。そのため例えば遷移金属Ｍのうちマンガンは、２．５ａｔｏｍｉｃ％以上３４ａｔｏｍｉｃ％以下であることが好ましい。なお遷移金属Ｍとして、必ずしもマンガンを含まなくてもよい。 However, if the proportion of manganese is too high, the discharge voltage and discharge capacity tend to decrease. Therefore, for example, it is preferable that manganese among the transition metals M is 2.5 atomic % or more and 34 atomic % or less. Note that the transition metal M does not necessarily have to contain manganese.
遷移金属Ｍ源８１は遷移金属Ｍを含む水溶液として用意する。ニッケル源としては、ニッケル塩、例えば硫酸ニッケル、塩化ニッケル、硝酸ニッケル、又はこれらの水和物の水溶液を用いることができる。また酢酸ニッケルをはじめとするニッケルの有機酸塩、又はこれらの水和物の水溶液を用いることができる。またニッケルアルコキシド又は有機ニッケル錯体の水溶液を用いることができる。なお本明細書等において、有機酸塩とは、酢酸、クエン酸、シュウ酸、ギ酸、酪酸等の有機酸と金属の化合物をいうこととする。 The transition metal M source 81 is prepared as an aqueous solution containing the transition metal M. As the nickel source, an aqueous solution of a nickel salt, for example, nickel sulfate, nickel chloride, nickel nitrate, or a hydrate thereof can be used. An aqueous solution of an organic acid salt of nickel, such as nickel acetate, or a hydrate thereof can also be used. An aqueous solution of a nickel alkoxide or an organic nickel complex can also be used. In this specification, an organic acid salt refers to a compound of an organic acid, such as acetic acid, citric acid, oxalic acid, formic acid, or butyric acid, and a metal.
コバルト源としては、コバルト塩、例えば硫酸コバルト、塩化コバルト、硝酸コバルト、又はこれらの水和物の水溶液を用いることができる。また酢酸コバルトをはじめとするコバルトの有機酸塩、又はこれらの水和物の水溶液を用いることができる。またコバルトアルコキシド、有機コバルト錯体の水溶液を用いることができる。 As the cobalt source, a cobalt salt, for example, cobalt sulfate, cobalt chloride, cobalt nitrate, or an aqueous solution of a hydrate thereof can be used. Also, an aqueous solution of an organic acid salt of cobalt, such as cobalt acetate, or a hydrate thereof can be used. Also, an aqueous solution of a cobalt alkoxide or an organic cobalt complex can be used.
マンガン源としては、マンガン塩、例えば硫酸マンガン、塩化マンガン、硝酸マンガン、又はこれらの水和物の水溶液を用いることができる。また酢酸マンガンをはじめとするマンガンの有機酸塩、又はこれらの水和物の水溶液を用いることができる。またマンガンアルコキシド、又は有機マンガン錯体の水溶液を用いることができる。 As the manganese source, a manganese salt, such as manganese sulfate, manganese chloride, manganese nitrate, or an aqueous solution of a hydrate thereof can be used. Also, an aqueous solution of an organic acid salt of manganese, such as manganese acetate, or a hydrate thereof can be used. Also, an aqueous solution of a manganese alkoxide or an organic manganese complex can be used.
本実施の形態では、遷移金属Ｍ源８１として、硫酸ニッケル、硫酸コバルト及び硫酸マンガンを純水に溶解させた水溶液を用意することとする。このときニッケル、コバルト及びマンガンの原子数比がＮｉ：Ｃｏ：Ｍｎ＝８：１：１又はこの近傍を満たすように秤量する。 In this embodiment, an aqueous solution of nickel sulfate, cobalt sulfate, and manganese sulfate dissolved in pure water is prepared as the transition metal M source 81. The nickel, cobalt, and manganese are weighed out so that the atomic ratio of Ni:Co:Mn is 8:1:1 or close to this.
＜添加元素源＞
図示しないが、遷移金属Ｍ源８１に添加元素源を添加してもよい。遷移金属Ｍ源８１に添加する添加元素を第１の添加元素と記す。具体的な第１の添加元素は例えばガリウム、アルミニウム、ホウ素及びインジウムの中から選ばれる一以上を有するとよい。 <Source of added elements>
Although not shown, an additive element source may be added to the transition metal M source 81. The additive element added to the transition metal M source 81 is referred to as a first additive element. Specifically, the first additive element may be one or more selected from the group consisting of gallium, aluminum, boron, and indium.
第１の添加元素がガリウムの場合、ガリウム源と記すことができる。ガリウム源としては、ガリウムを有する化合物を用いることができる。ガリウムを有する化合物は、例えば硫酸ガリウム、塩化ガリウム、若しくは硝酸ガリウム、又はこれらの水和物を用いることができる。またガリウムを有する化合物として、ガリウムアルコキシド、又は有機ガリウム錯体を用いてもよい。またさらにガリウムを有する化合物として、酢酸ガリウムをはじめとするガリウムの有機酸、又はこれらの水和物を用いてもよい。 When the first additive element is gallium, it can be referred to as a gallium source. As the gallium source, a compound containing gallium can be used. As the compound containing gallium, for example, gallium sulfate, gallium chloride, or gallium nitrate, or a hydrate thereof can be used. As the compound containing gallium, a gallium alkoxide or an organic gallium complex can be used. As the compound containing gallium, an organic acid of gallium such as gallium acetate, or a hydrate thereof can be used.
第１の添加元素がアルミニウムの場合、アルミニウム源と記すことができる。アルミニウム源としては、アルミニウムを有する化合物を用いることができる。アルミニウムを有する化合物は、例えば硫酸アルミニウム、塩化アルミニウム、若しくは硝酸アルミニウム、又はこれらの水和物を用いることができる。またアルミニウムを有する化合物として、アルミニウムアルコキシド、又は有機アルミニウム錯体を用いてもよい。またさらにアルミニウムを有する化合物として、酢酸アルミニウムをはじめとするアルミニウムの有機酸、又はこれらの水和物を用いてもよい。 When the first added element is aluminum, it can be referred to as an aluminum source. As the aluminum source, a compound containing aluminum can be used. As the compound containing aluminum, for example, aluminum sulfate, aluminum chloride, or aluminum nitrate, or a hydrate thereof can be used. As the compound containing aluminum, an aluminum alkoxide or an organic aluminum complex can be used. As the compound containing aluminum, an organic acid of aluminum such as aluminum acetate, or a hydrate thereof can be used.
第１の添加元素がホウ素の場合、ホウ素源と記すことができる。ホウ素源としては、ホウ素を有する化合物を用いることができる。ホウ素を有する化合物は、例えばホウ酸又はホウ酸塩を用いることができる。 When the first additive element is boron, it can be referred to as a boron source. As the boron source, a compound containing boron can be used. As the compound containing boron, for example, boric acid or a borate can be used.
第１の添加元素がインジウムの場合、インジウム源と記すことができる。インジウム源としては、インジウムを有する化合物を用いることができる。インジウムを有する化合物は、例えば硫酸インジウム、塩化インジウム、若しくは硝酸インジウム、又はこれらの水和物を用いることができる。またインジウムを有する化合物として、インジウムアルコキシド、又は有機インジウム錯体を用いてもよい。またさらにインジウムを有する化合物として、酢酸インジウムをはじめとするインジウムの有機酸、又はこれらの水和物を用いてもよい。 When the first additive element is indium, it can be referred to as an indium source. As the indium source, a compound containing indium can be used. As the compound containing indium, for example, indium sulfate, indium chloride, or indium nitrate, or a hydrate thereof can be used. As the compound containing indium, an indium alkoxide or an organic indium complex can be used. As the compound containing indium, an organic acid of indium such as indium acetate, or a hydrate thereof can be used.
第１の添加元素源として溶液を用いる場合、上記化合物を有する水溶液を用意する。 When using a solution as the source of the first additive element, prepare an aqueous solution containing the above compound.
＜キレート剤＞
図１４に示すキレート剤８３について説明する。キレート剤を構成する材料として、例えばグリシン、オキシン、１−ニトロソ−２−ナフトール、２−メルカプトベンゾチアゾール又はＥＤＴＡ（エチレンジアミン四酢酸）が挙げられる。なお、グリシン、オキシン、１−ニトロソ−２−ナフトール又は２−メルカプトベンゾチアゾールから選ばれた複数種を用いてもよい。なおこれらを純水に溶解させた水溶液がキレート剤となり、グリシンを溶解させた水溶液はグリシン水溶液と記すことがある。キレート剤は、キレート化合物を作る錯化剤であり、一般的な錯化剤より好ましい。勿論キレート剤でなく錯化剤を用いてもよく、錯化剤としてアンモニア水を用いることができる。 <Chelating Agent>
The chelating agent 83 shown in FIG. 14 will be described. Examples of materials constituting the chelating agent include glycine, oxine, 1-nitroso-2-naphthol, 2-mercaptobenzothiazole, and EDTA (ethylenediaminetetraacetic acid). Note that a plurality of types selected from glycine, oxine, 1-nitroso-2-naphthol, and 2-mercaptobenzothiazole may be used. Note that an aqueous solution in which these are dissolved in pure water becomes a chelating agent, and an aqueous solution in which glycine is dissolved may be referred to as a glycine aqueous solution. A chelating agent is a complexing agent that creates a chelate compound, and is preferable to a general complexing agent. Of course, a complexing agent may be used instead of a chelating agent, and ammonia water may be used as the complexing agent.
キレート剤を用いることで、共沈物、例えばコバルト化合物を得る際の反応槽のｐＨが制御しやすくなり好ましい。またキレート剤を用いることで結晶の核の不要な発生を抑え、成長を促すことができ好ましい。不要な核の発生が抑制されると微粒子の生成が抑制されるため、粒度分布が良好な複合酸化物を得ることができる。またキレート剤を用いることで、酸塩基反応を遅らせることができ、当該反応が徐々に進むことで球状に近い二次粒子を得ることができる。 The use of a chelating agent is preferable because it makes it easier to control the pH of the reaction tank when obtaining a coprecipitate, for example a cobalt compound. The use of a chelating agent is also preferable because it suppresses the generation of unnecessary crystal nuclei and promotes growth. Suppressing the generation of unnecessary nuclei suppresses the generation of fine particles, making it possible to obtain a complex oxide with a good particle size distribution. The use of a chelating agent also makes it possible to delay the acid-base reaction, and as the reaction progresses gradually, it is possible to obtain secondary particles that are nearly spherical.
グリシンは９以上１０以下及びその付近のｐＨにて、当該ｐＨ値を一定に保つ作用があり、キレート剤としてグリシン水溶液を用いることで、上記コバルト化合物を得る際の反応槽のｐＨが制御しやすくなり好ましい。さらにグリシン水溶液のグリシン濃度は、酸性溶液９１において、０．０５モル／Ｌ以上０．０９モル／Ｌ以下とするとよい。 Glycine has the effect of keeping the pH value constant at or near a pH of 9 or more and 10 or less, and using an aqueous glycine solution as a chelating agent is preferable because it makes it easier to control the pH of the reaction tank when obtaining the cobalt compound. Furthermore, the glycine concentration of the aqueous glycine solution is preferably 0.05 mol/L or more and 0.09 mol/L or less in the acidic solution 91.
＜純水＞
本実施の形態に用いられる水溶液は、純水が用いられると好ましい。純水とは、比抵抗が１ＭΩ・ｃｍ以上の水、より好ましくは比抵抗が１０ＭΩ・ｃｍ以上の水、さらに好ましくは比抵抗が１５ＭΩ・ｃｍ以上の水である。当該比抵抗を満たす水は純度が高く、含有される不純物が非常に少ない。 <Pure water>
The aqueous solution used in the present embodiment is preferably pure water. Pure water is water having a resistivity of 1 MΩ cm or more, more preferably 10 MΩ cm or more, and even more preferably 15 MΩ cm or more. Water that satisfies the resistivity range has high purity and contains very few impurities.
＜ステップＳ３０＞
次に図１４に示すステップＳ３０で遷移金属Ｍ源８１とキレート剤８３とを混合して、酸性溶液９１を作製する。 <Step S30>
Next, in step S30 shown in FIG. 14, a transition metal M source 81 and a chelating agent 83 are mixed to prepare an acidic solution 91.
＜アルカリ性溶液＞
次に図１４に示すアルカリ性溶液８４について説明する。アルカリ性溶液は、例えば水酸化ナトリウム、水酸化カリウム、水酸化リチウム又はアンモニアを有する水溶液を用いればよく、ｐＨ調整剤として機能すればこれら水溶液に限定されない。例えば水酸化ナトリウム、水酸化カリウム、又は水酸化リチウムから選ばれた複数種を水に溶解させた水溶液でもよい。水は上記純水を用いるとよい。 <Alkaline solution>
Next, the alkaline solution 84 shown in Fig. 14 will be described. The alkaline solution may be, for example, an aqueous solution containing sodium hydroxide, potassium hydroxide, lithium hydroxide, or ammonia, and is not limited to these aqueous solutions as long as it functions as a pH adjuster. For example, an aqueous solution in which a plurality of types selected from sodium hydroxide, potassium hydroxide, and lithium hydroxide are dissolved in water may be used. The water used may be the above-mentioned pure water.
上記アルカリ性溶液８４とともに水又は水溶液を用意してもよい。水又は水溶液は張込液又は調整液と記す場合があり、反応初期状態の水溶液全般を指すことがある。水は上記純水を用いるとよい。また水溶液として上記純水を含むキレート剤を用いてもよい。キレート剤を用いた場合、上記＜キレート剤＞で説明したような効果がある。なお水又は水溶液は必ずしも用意しなくてよい。 Water or an aqueous solution may be prepared together with the alkaline solution 84. The water or aqueous solution may be referred to as the charging solution or the adjustment solution, and may refer to any aqueous solution in the initial reaction state. The water may be the above-mentioned pure water. A chelating agent containing the above-mentioned pure water may also be used as the aqueous solution. When a chelating agent is used, the effect described above in <Chelating Agent> is obtained. It is not necessary to prepare water or an aqueous solution.
＜ステップＳ３１＞
次に図１４に示すステップＳ３１について説明する。ステップＳ３１では、酸性溶液９１と、アルカリ性溶液８４とを混合する。混合により、酸性溶液９１と、アルカリ性溶液８４とが反応して、共沈物９５を得ることができる。 <Step S31>
Next, step S31 shown in Fig. 14 will be described. In step S31, the acidic solution 91 and the alkaline solution 84 are mixed. By mixing, the acidic solution 91 and the alkaline solution 84 react with each other, and a coprecipitate 95 can be obtained.
ステップ３１における上記反応は、中和反応、酸塩基反応、又は共沈反応と記すことがある。得られた共沈物９５は、正極活物質の前駆体と記すことがある。 The above reaction in step 31 may be referred to as a neutralization reaction, an acid-base reaction, or a co-precipitation reaction. The resulting coprecipitate 95 may be referred to as a precursor of the positive electrode active material.
＜反応条件＞
共沈法に従って、酸性溶液９１とアルカリ性溶液８４とを混合する場合、反応系のｐＨが９以上１１以下、好ましくはｐＨが９．８以上１０．３以下となるようにする。例えば酸性溶液９１を反応槽が有する反応容器等（例えばビーカー）に入れ、アルカリ性溶液８４を反応容器へ滴下する場合、反応容器の水溶液のｐＨが上記条件の範囲を満たす又は上記条件の範囲を維持するとよい。上記条件の範囲を維持するとは、アルカリ性溶液８４を滴下して反応容器の水溶液のｐＨの値が変動した場合、当該滴下から一定時間経過したときに反応容器の水溶液のｐＨが上記範囲を満たすことが含まれる。一定時間とは、１秒以上５秒以下、好ましくは１秒以上３秒以下である。またアルカリ性溶液８４を反応容器に入れておき、酸性溶液９１を滴下する場合も、同様に反応容器の水溶液のｐＨが上記条件の範囲を満たす又は上記条件の範囲を維持するとよい。酸性溶液９１又はアルカリ性溶液８４の滴下速度は、ｐＨ条件の制御しやすさを鑑み、０．２ｍＬ／分以上０．８ｍＬ／分以下とするとよい。 <Reaction conditions>
When the acidic solution 91 and the alkaline solution 84 are mixed according to the coprecipitation method, the pH of the reaction system is set to 9 or more and 11 or less, preferably 9.8 or more and 10.3 or less. For example, when the acidic solution 91 is placed in a reaction vessel or the like (e.g., a beaker) of the reaction tank and the alkaline solution 84 is dropped into the reaction vessel, it is preferable that the pH of the aqueous solution in the reaction vessel satisfies or maintains the above-mentioned range of conditions. The term "maintaining the above-mentioned range of conditions" includes that when the pH value of the aqueous solution in the reaction vessel fluctuates due to the dropping of the alkaline solution 84, the pH of the aqueous solution in the reaction vessel satisfies the above-mentioned range when a certain time has elapsed since the dropping. The certain time is 1 second or more and 5 seconds or less, preferably 1 second or more and 3 seconds or less. Similarly, when the alkaline solution 84 is placed in the reaction vessel and the acidic solution 91 is dropped, it is preferable that the pH of the aqueous solution in the reaction vessel satisfies or maintains the above-mentioned range of conditions. The dropping speed of the acidic solution 91 or the alkaline solution 84 is preferably set to 0.2 mL/min or more and 0.8 mL/min or less in consideration of ease of control of the pH condition.
反応容器では攪拌手段を用いてアルカリ性溶液８４又は酸性溶液９１を攪拌しておくとよい。攪拌手段はスターラーを用いることができ、具体的には攪拌翼を有したスターラーを用いることができる。スターラーには２枚以上６枚以下の攪拌翼を設けることができ、例えば４枚の攪拌翼とする場合、上方からみて十字状に配置するとよい。攪拌手段の回転数は、８００ｒｐｍ以上１２００ｒｐｍ以下とするとよい。 In the reaction vessel, the alkaline solution 84 or the acidic solution 91 may be stirred using a stirring means. The stirring means may be a stirrer, specifically a stirrer with stirring blades. The stirrer may be provided with 2 to 6 stirring blades, and when using 4 stirring blades, for example, they may be arranged in a cross shape when viewed from above. The rotation speed of the stirring means may be 800 rpm to 1200 rpm.
反応容器のアルカリ性溶液８４又は酸性溶液９１は５０℃以上９０℃以下となるように調整する。アルカリ性溶液８４及び酸性溶液９１のいずれか一方の滴下は、当該温度になったのちに開始するとよい。 The alkaline solution 84 or acidic solution 91 in the reaction vessel is adjusted to a temperature between 50°C and 90°C. Dripping of either the alkaline solution 84 or the acidic solution 91 should begin after the solution has reached that temperature.
また反応容器内は不活性雰囲気とするとよい。例えば窒素雰囲気とする場合、窒素ガスを０．５Ｌ／分以上２Ｌ／分以下の流量で導入するとよい。 The inside of the reaction vessel should preferably be in an inert atmosphere. For example, if a nitrogen atmosphere is used, nitrogen gas should be introduced at a flow rate of 0.5 L/min to 2 L/min.
また反応槽に還流冷却器を配置してもよい。当該還流冷却器により、窒素ガスを反応容器から放出させることができる。還流冷却で生じた水は反応容器に戻すことができる。 A reflux condenser may also be placed in the reaction vessel. The reflux condenser allows nitrogen gas to be released from the reaction vessel. Water produced by reflux cooling can be returned to the reaction vessel.
上記反応を経ると反応容器に共沈物９５として例えばコバルト化合物が沈殿する。当該共沈物９５を回収するために濾過を行うと好ましい。濾過の際、反応容器に沈殿した反応生成物を純水で洗浄した後に、沸点の低い有機溶媒（例えばアセトン等）を加えてから上記濾過を行うと好ましい。 After the above reaction, for example, a cobalt compound is precipitated in the reaction vessel as a coprecipitate 95. It is preferable to perform filtration to recover the coprecipitate 95. When filtering, it is preferable to wash the reaction product precipitated in the reaction vessel with pure water, and then add an organic solvent with a low boiling point (e.g., acetone, etc.) before performing the above filtration.
濾過後の共沈物９５はさらに乾燥させると好ましい。例えば６０℃以上９０℃以下の真空雰囲気下にて、０．５時間以上３時間以下で乾燥させる。このような手順を経て、共沈物９５を得てもよい。 It is preferable to further dry the coprecipitate 95 after filtration. For example, it is dried in a vacuum atmosphere at 60°C to 90°C for 0.5 hours to 3 hours. Coprecipitate 95 may be obtained through such a procedure.
共沈物９５であるコバルト化合物は、水酸化コバルト（例えばＣｏ（ＯＨ）２等）であると好ましい。濾過後の水酸化コバルトは、一次粒子が凝集した二次粒子として得られる。 The cobalt compound of the coprecipitate 95 is preferably cobalt hydroxide (e.g., Co(OH) 2 , etc.). The cobalt hydroxide obtained after filtration is obtained as secondary particles formed by agglomeration of primary particles.
＜リチウム源＞
次に図１４に示すリチウム源８８（図面ではＬｉ源と記す）としてリチウム化合物を用意する。リチウム化合物として、水酸化リチウム、炭酸リチウム、酸化リチウム又は硝酸リチウムを用意する。例えば共沈物９５として水酸化コバルトが得られた場合、リチウム化合物は水酸化リチウムを用いることができる。 <Lithium source>
Next, a lithium compound is prepared as the lithium source 88 (referred to as Li source in the drawing) shown in Fig. 14. As the lithium compound, lithium hydroxide, lithium carbonate, lithium oxide, or lithium nitrate is prepared. For example, when cobalt hydroxide is obtained as the coprecipitate 95, lithium hydroxide can be used as the lithium compound.
リチウム化合物は粉砕しておくとよい。当該乳鉢は不純物を放出しない材質が好ましく、具体的には、純度が９０ｗｔ％以上、好ましくは純度が９９ｗｔ％以上のアルミナの乳鉢を用いるとよい。またボールミルを用いた湿式粉砕を用いてもよい。湿式粉砕では、溶媒にアセトンを用いることができる。 The lithium compound should be crushed in advance. The mortar should preferably be made of a material that does not release impurities. Specifically, an alumina mortar with a purity of 90 wt% or more, preferably 99 wt% or more, should be used. Wet crushing using a ball mill may also be used. Acetone can be used as the solvent in wet crushing.
＜ステップＳ４１＞
次に図１４に示すステップＳ４１では、共沈物９５とリチウム源８８とを混合する。その後、混合された混合物９７を得る。共沈物９５とリチウム源８８とを混合する手段に公転自転攪拌装置を用いるとよい。公転自転攪拌装置はメディアを使用しないため、粉砕が行われないことが多い。 <Step S41>
14, the coprecipitate 95 and the lithium source 88 are mixed. Then, a mixed mixture 97 is obtained. A revolutionary agitator may be used as a means for mixing the coprecipitate 95 and the lithium source 88. Since the revolutionary agitator does not use media, pulverization is often not performed.
共沈物９５とリチウム源８８との混合と同じステップに粉砕を行う場合、ボールミル又はビーズミルを用いることもできる。ボールミル又はビーズミルのメディアにはアルミナボール又はジルコニアボールを用いることができる。ボールミル又はビーズミルでは、メディアに遠心力が付加されるため、微粒子化が可能となる。メディア等からのコンタミネーションが懸念される場合は、上記ジルコニアボールを用いることが好ましい。 When grinding is performed in the same step as mixing the coprecipitate 95 and the lithium source 88, a ball mill or a bead mill can be used. Alumina balls or zirconia balls can be used as the media for the ball mill or bead mill. In a ball mill or bead mill, centrifugal force is applied to the media, making it possible to microparticulate the material. If there is a concern about contamination from the media, etc., it is preferable to use the above-mentioned zirconia balls.
粉砕を同じステップで行う場合、乾式粉砕と湿式粉砕とがある。乾式粉砕は、不活性ガス又は空気中で粉砕するものであり、粒子径が３．５μｍ以下、好ましくは３μｍ以下まで粉砕することができる。湿式粉砕は液体中で粉砕するものであり、粒子径がナノサイズまで粉砕することができる。すなわち粒子径を小さくしたい場合は湿式粉砕を用いるとよい。 When grinding is performed in the same step, there are dry grinding and wet grinding. Dry grinding is performed in an inert gas or air, and can grind to a particle size of 3.5 μm or less, preferably 3 μm or less. Wet grinding is performed in a liquid, and can grind to a particle size of nanometers. In other words, wet grinding is recommended if you want to reduce the particle size.
このようにして混合物９７を得る。 In this way, mixture 97 is obtained.
＜ステップＳ４４＞
次に図１４に示すステップＳ４４では、混合物を加熱する。当該ステップＳ４４は本焼成と記すことがある。加熱後、正極活物質９０として複合酸化物を得ることができる。正極活物質９０は前駆体である共沈物９５の形状を反映することがある。 <Step S44>
14, the mixture is heated. Step S44 may be referred to as a main baking. After heating, a composite oxide may be obtained as a positive electrode active material 90. The positive electrode active material 90 may have a shape similar to that of the coprecipitate 95, which is a precursor.
＜加熱条件＞
加熱温度は７００℃以上１１００℃未満で行うことが好ましく、８００℃以上１０００℃以下で行うことがより好ましく、８００℃以上９５０℃以下がさらに好ましい。本加熱処理を経てコバルト酸化物を製造する点において、少なくとも共沈物９５とリチウム源８８とが相互に拡散する温度で加熱する。当該温度が本焼成と呼ばれる理由である。 <Heating conditions>
The heating temperature is preferably 700° C. or more and less than 1100° C., more preferably 800° C. or more and 1000° C. or less, and even more preferably 800° C. or more and 950° C. or less. In terms of producing cobalt oxide through this heat treatment, heating is performed at a temperature at which at least the coprecipitate 95 and the lithium source 88 diffuse into each other. This temperature is the reason why it is called the main calcination.
加熱時間は例えば１時間以上１００時間以下行うことができ、２時間以上２０時間以下とすることが好ましい。 The heating time can be, for example, from 1 hour to 100 hours, and preferably from 2 hours to 20 hours.
加熱雰囲気は、酸素を有する雰囲気、又はいわゆる乾燥空気であって水が少ない酸素含有雰囲気（例えば露点が−５０℃以下、より好ましくは露点が−８０℃以下）で行うことが好ましい。 The heating atmosphere is preferably an oxygen-containing atmosphere or a so-called dry air atmosphere containing oxygen with little water (e.g., a dew point of -50°C or less, more preferably a dew point of -80°C or less).
例えば、７５０℃で１０時間加熱する場合、昇温速度は１５０℃／時間以上２５０℃／時間以下とするとよい。また乾燥雰囲気を構成しうる乾燥空気の流量は３Ｌ／分以上１０Ｌ／分以下とすることが好ましい。降温時間については、規定温度から室温となるまで１０時間以上５０時間以下とすることが好ましく、降温速度は降温時間等から計算することができる。 For example, when heating at 750°C for 10 hours, the temperature increase rate should be 150°C/hour or more and 250°C/hour or less. The flow rate of dry air that can form the drying atmosphere is preferably 3 L/min or more and 10 L/min or less. The temperature decrease time is preferably 10 hours or more and 50 hours or less until the temperature drops from the specified temperature to room temperature, and the temperature decrease rate can be calculated from the temperature decrease time, etc.
加熱の際に用いる、るつぼ、サヤ、セッター、又は容器は不純物を放出しない材質であると好ましい。例えば純度が９９．９％のアルミナのるつぼを用いるとよい。量産する場合にはムライト・コーディライト（Ａｌ２Ｏ３、ＳｉＯ２、ＭｇＯ）のサヤを用いるとよい。 The crucible, scabbard, setter, or container used during heating is preferably made of a material that does not emit impurities. For example, a crucible made of alumina with a purity of 99.9% is preferably used. For mass production, a scabbard made of mullite-cordierite (Al 2 O 3 , SiO 2 , MgO) is preferably used.
また加熱が終わった材料を回収する際に、るつぼから乳鉢へ移動させたのち、回収すると材料に不純物が混入しないため好ましい。また、当該乳鉢についても、不純物を放出しない材質が好ましく、具体的には、純度が９０ｗｔ％以上、好ましくは純度が９９ｗｔ％以上のアルミナ又はジルコニアの乳鉢を用いるとよい。 In addition, when recovering the material after heating, it is preferable to move it from the crucible to a mortar and then recover it, as this prevents impurities from being mixed into the material. In addition, it is preferable for the mortar to be made of a material that does not release impurities, and specifically, it is recommended to use a mortar made of alumina or zirconia with a purity of 90 wt% or more, preferably 99 wt% or more.
以上のとおり、正極活物質９０を製造することができ、製造方法１に従うと正極活物質９０としてＮＣＭを得ることができる。ＮＣＭは複合酸化物と記すことがある。 As described above, the positive electrode active material 90 can be produced, and according to production method 1, NCM can be obtained as the positive electrode active material 90. NCM is sometimes referred to as a composite oxide.
製造方法１に従うと正極活物質９０に含まれる不純物が少なく好ましい。ただし出発材料に硫化物を使用する場合は正極活物質９０から硫黄が検出されることがある。ＧＤ−ＭＳ、ＩＣＰ−ＭＳ等を用いて正極活物質９０の元素分析を行い、硫黄の濃度を測定することができる。 When manufacturing method 1 is used, the amount of impurities contained in the positive electrode active material 90 is low, which is preferable. However, when a sulfide is used as the starting material, sulfur may be detected in the positive electrode active material 90. The sulfur concentration can be measured by performing elemental analysis of the positive electrode active material 90 using GD-MS, ICP-MS, etc.
以上のとおり、本実施の形態では、上記実施の形態に適用できる正極活物質を共沈法により作製する例を示したが、上記の例に限定解釈されるものではない。 As described above, in this embodiment, an example of producing a positive electrode active material that can be applied to the above embodiment by coprecipitation has been shown, but the interpretation is not limited to the above example.
本実施の形態は、他の実施の形態と適宜組み合わせて用いることができる。 This embodiment can be used in appropriate combination with other embodiments.
（実施の形態４）
本実施の形態では、上記実施の形態に適用できる正極活物質の製造方法２について説明する。具体的には正極活物質を液相法により製造する方法について、図１５等を用いて説明する。本実施の形態で示す正極活物質の製造方法２は、断りのない限り、第１のバッテリ１０１ａ、及び／又は第２のバッテリ１０１ｂに適用できる。 (Embodiment 4)
In this embodiment, a method for manufacturing a positive electrode active material 2 that can be applied to the above-mentioned embodiment will be described. Specifically, a method for manufacturing a positive electrode active material by a liquid phase method will be described with reference to Fig. 15 and the like. Unless otherwise specified, the method for manufacturing a positive electrode active material 2 shown in this embodiment can be applied to the first battery 101a and/or the second battery 101b.
［正極活物質の製造方法２］
図１５のステップＳ３０ａにおいて、リチウム化合物８０３を用意する。また、ステップＳ３０ｂにおいて、リン化合物８０４を用意する。 [Method of manufacturing positive electrode active material 2]
15, a lithium compound 803 is prepared in step S30a, and a phosphorus compound 804 is prepared in step S30b.
ここで、後述する正極活物質９０として得られることが好ましい複合酸化物のリチウム、遷移金属Ｍ、及びリンの原子数比をｘ：ｙ：ｚとする。ＬｉＭＰＯ４を得るためには例えばｘ：ｙ：ｚ＝１：１：１とすればよい。 Here, the atomic ratio of lithium, transition metal M, and phosphorus in a composite oxide preferably obtained as a positive electrode active material 90 described later is defined as x:y:z. In order to obtain LiMPO4, for example, x:y:z=1:1:1 may be used.
リチウム化合物の代表例としては、塩化リチウム（ＬｉＣｌ）、酢酸リチウム（ＣＨ３ＣＯＯＬｉ）、シュウ酸リチウム（（ＣＯＯＬｉ）２）、炭酸リチウム（Ｌｉ２ＣＯ３）、水酸化リチウム一水和物（ＬｉＯＨ・Ｈ２Ｏ）等がある。 Representative examples of lithium compounds include lithium chloride (LiCl), lithium acetate (CH 3 COOLi), lithium oxalate ((COOLi) 2 ), lithium carbonate (Li 2 CO 3 ), and lithium hydroxide monohydrate (LiOH.H 2 O).
リン化合物の代表例としては、オルトリン酸（Ｈ３ＰＯ４）等のリン酸、リン酸水素二アンモニウム（（ＮＨ４）２ＨＰＯ４）、リン酸二水素アンモニウム（ＮＨ４Ｈ２ＰＯ４）等のリン酸水素アンモニウム等がある。 Representative examples of phosphorus compounds include phosphoric acids such as orthophosphoric acid (H 3 PO 4 ), and ammonium hydrogen phosphates such as diammonium hydrogen phosphate ((NH 4 ) 2 HPO 4 ) and ammonium dihydrogen phosphate (NH 4 H 2 PO 4 ).
次に、図１５のステップＳ３０ｃにおいて、溶媒８０５を用意する。溶媒８０５として水を用いることが好ましい。また、溶媒８０５として水と他の液体との混合液を用いてもよい。例えば、水とアルコールを混合してもよい。ここで、リチウム化合物８０３及びリン化合物８０４、あるいはリチウム化合物８０３とリン化合物８０４との反応生成物は、水に対する溶解度とアルコールに対する溶解度が異なる場合がある。アルコールを用いることにより、形成される粒子の粒径がより小さくなる場合がある。 Next, in step S30c of FIG. 15, a solvent 805 is prepared. It is preferable to use water as the solvent 805. Alternatively, a mixture of water and another liquid may be used as the solvent 805. For example, water may be mixed with alcohol. Here, the lithium compound 803 and the phosphorus compound 804, or the reaction product of the lithium compound 803 and the phosphorus compound 804, may have different solubilities in water and alcohol. By using alcohol, the particle size of the formed particles may be smaller.
なお、溶媒８０５として水を用いる場合、好ましくは比抵抗が１ＭΩ・ｃｍ以上、より好ましくは比抵抗が１０ＭΩ・ｃｍ以上、さらに好ましくは比抵抗が１５ＭΩ・ｃｍ以上の、不純物が少ない純水であることが望ましい。高純度の材料を用いることで、二次電池の容量を高めること、及び／又は二次電池の信頼性を高めることができる。 When water is used as the solvent 805, it is desirable that the solvent be pure water with few impurities and preferably with a resistivity of 1 MΩ·cm or more, more preferably with a resistivity of 10 MΩ·cm or more, and even more preferably with a resistivity of 15 MΩ·cm or more. By using a high-purity material, the capacity of the secondary battery can be increased and/or the reliability of the secondary battery can be increased.
次に、図１５のステップＳ３１として、リチウム化合物８０３、リン化合物８０４、及び溶媒８０５を混合し、ステップＳ３２の混合物８１１を得る。ステップＳ３１の混合は、大気、不活性ガス、等の雰囲気下で行うことができる。不活性ガスとして例えば窒素を用いればよい。ここでは一例として、大気雰囲気下で、ステップＳ３０ａで用意したリチウム化合物８０３と、ステップＳ３０ｂで用意したリン化合物８０４と、ステップＳ３０ｃで用意した溶媒８０５と、を混合する。例えば、ステップＳ３０ｃで用意した溶媒８０５に、ステップＳ３０ａで用意したリチウム化合物８０３と、ステップＳ３０ｂで用意したリン化合物８０４を入れ、ステップＳ３２の混合物８１１を形成する。 Next, in step S31 of FIG. 15, the lithium compound 803, the phosphorus compound 804, and the solvent 805 are mixed to obtain a mixture 811 in step S32. The mixing in step S31 can be performed in an atmosphere such as air or an inert gas. For example, nitrogen may be used as the inert gas. Here, as an example, the lithium compound 803 prepared in step S30a, the phosphorus compound 804 prepared in step S30b, and the solvent 805 prepared in step S30c are mixed in an air atmosphere. For example, the lithium compound 803 prepared in step S30a and the phosphorus compound 804 prepared in step S30b are added to the solvent 805 prepared in step S30c to form the mixture 811 in step S32.
図１５のステップＳ３２の混合物８１１において、リチウム化合物８０３、リン化合物８０４、及び該リチウム化合物と該リン化合物との反応生成物は、溶液に沈殿する場合があるが、一部は沈殿せずに溶媒に溶解する、すなわちイオンとして溶媒内に存在する。ここで、混合物８１１のｐＨが低いと、該反応生成物等が溶媒に溶解しやすい場合があり、高いと、該反応生成物等が沈殿しやすい場合がある。 In the mixture 811 in step S32 of FIG. 15, the lithium compound 803, the phosphorus compound 804, and the reaction products of the lithium compound and the phosphorus compound may precipitate in the solution, but some of them do not precipitate and dissolve in the solvent, that is, they exist in the solvent as ions. Here, if the pH of the mixture 811 is low, the reaction products may be easily dissolved in the solvent, and if the pH is high, the reaction products may be easily precipitated.
なお、リチウム化合物８０３及びリン化合物８０４を混合し、ステップＳ３２の混合物８１１を形成する代わりに、Ｌｉ３ＰＯ４，Ｌｉ２ＨＰＯ４，ＬｉＨ２ＰＯ４等、のリンとリチウムを有する化合物を用意し、溶媒に加えてステップＳ３２の混合物８１１を形成してもよい。 It should be noted that, instead of mixing the lithium compound 803 and the phosphorus compound 804 to form the mixture 811 in step S32, a compound having phosphorus and lithium, such as Li3PO4 , Li2HPO4 , or LiH2PO4 , may be prepared and added to a solvent to form the mixture 811 in step S32.
ここでステップＳ３２の混合物８１１が水溶液である場合、混合物８１１のｐＨは、混合物８１１が有する塩の種類及び解離度により決定される。よって、原料として用いるリチウム化合物８０３及びリン化合物８０４により、混合物８１１のｐＨは変化する。例えば、リチウム化合物８０３として塩化リチウム、リン化合物８０４としてオルトリン酸を用いる場合には、ステップＳ３２の混合物８１１は強酸となる。また例えば、リチウム化合物８０３として水酸化リチウム一水和物を用いる場合には、ステップＳ３２の混合物８１１はアルカリ性となりやすい。 Here, when the mixture 811 in step S32 is an aqueous solution, the pH of the mixture 811 is determined by the type and degree of dissociation of the salt contained in the mixture 811. Therefore, the pH of the mixture 811 changes depending on the lithium compound 803 and the phosphorus compound 804 used as raw materials. For example, when lithium chloride is used as the lithium compound 803 and orthophosphoric acid is used as the phosphorus compound 804, the mixture 811 in step S32 becomes a strong acid. Also, for example, when lithium hydroxide monohydrate is used as the lithium compound 803, the mixture 811 in step S32 tends to become alkaline.
次に、図１５のステップＳ３３において溶液Ｐ８１２を用意する。次に、ステップＳ３５において、ステップＳ３２の混合物８１１と、ステップＳ３３で用意した溶液Ｐ８１２と、を混合し、ステップＳ４１の混合物８２１を形成する。ここで、加える溶液Ｐ８１２の量あるいは濃度を調整することにより、得られるステップＳ４１の混合物８２１、及び後に得られるステップＳ８２の混合物８３１のｐＨを調整することができる。ステップＳ３５において例えば、ステップＳ３２の混合物８１１のｐＨを測定しながら溶液Ｐ８１２を滴下すればよい。溶液Ｐ８１２としては、ステップＳ３２の混合物８１１のｐＨに応じて、アルカリ性溶液、又は酸性溶液を用いる。ここで弱アルカリ性、又は弱酸性の溶液を用いることにより、ｐＨの調整がしやすくなる場合がある。例えばアルカリ性溶液のｐＨは、８以上１２以下とすればよい。また、酸性溶液のｐＨは、２以上６以下とすればよい。アルカリ性溶液として例えば、アンモニア水を用いればよい。後述するステップＳ８２の混合物８３１が酸性又は中性となるように、溶液Ｐ８１２のｐＨ及び混合量を決定することが好ましい。 Next, in step S33 of FIG. 15, a solution P812 is prepared. Next, in step S35, the mixture 811 of step S32 and the solution P812 prepared in step S33 are mixed to form a mixture 821 of step S41. Here, by adjusting the amount or concentration of the solution P812 to be added, the pH of the mixture 821 of step S41 obtained and the mixture 831 of step S82 obtained later can be adjusted. In step S35, for example, the solution P812 may be dropped while measuring the pH of the mixture 811 of step S32. As the solution P812, an alkaline solution or an acidic solution is used depending on the pH of the mixture 811 of step S32. Here, by using a weak alkaline or weak acidic solution, it may be easier to adjust the pH. For example, the pH of the alkaline solution may be 8 or more and 12 or less. Also, the pH of the acidic solution may be 2 or more and 6 or less. For example, ammonia water may be used as the alkaline solution. It is preferable to determine the pH and mixing amount of solution P812 so that the mixture 831 in step S82 described below is acidic or neutral.
次に、図１５のステップＳ４２において、遷移金属Ｍ源８２２を用意する。遷移金属Ｍ源８２２として、鉄（ＩＩ）化合物、マンガン（ＩＩ）化合物、コバルト（ＩＩ）化合物、及びニッケル（ＩＩ）化合物（以下、Ｍ（ＩＩ）化合物と示す。）の一以上を用いることができる。 Next, in step S42 of FIG. 15, a transition metal M source 822 is prepared. As the transition metal M source 822, one or more of an iron (II) compound, a manganese (II) compound, a cobalt (II) compound, and a nickel (II) compound (hereinafter referred to as an M (II) compound) can be used.
なお、合成の際に用いる遷移金属Ｍ源としては、高純度の材料を用いると好ましい。具体的には、当該材料の純度としては、３Ｎ（９９．９％）以上、好ましくは４Ｎ（９９．９９％）以上、より好ましくは４Ｎ５（９９．９９５％）以上、さらに好ましくは５Ｎ（９９．９９９％）以上である。高純度の材料を用いることで、電池セルの容量を高めること、又は電池セルの信頼性を高めることができる。 It is preferable to use a high-purity material as the transition metal M source used in the synthesis. Specifically, the purity of the material is 3N (99.9%) or more, preferably 4N (99.99%) or more, more preferably 4N5 (99.995%) or more, and even more preferably 5N (99.999%) or more. By using a high-purity material, it is possible to increase the capacity of the battery cell or improve the reliability of the battery cell.
加えて、このときの遷移金属Ｍ源の結晶性が高いと好適である。例えば、遷移金属源は、単結晶粒を有すると好適である。遷移金属源の結晶性の評価としては、例えば、ＴＥＭ（透過型電子顕微鏡）像、ＳＴＥＭ（走査透過型電子顕微鏡）像、ＨＡＡＤＦ−ＳＴＥＭ（高角散乱環状暗視野走査透過型電子顕微鏡）像、ＡＢＦ−ＳＴＥＭ（環状明視野走査透過型電子顕微鏡）像等から判断することができる。また、遷移金属源の結晶性の評価としては、Ｘ線回折（ＸＲＤ）、電子線回折、中性子線回折等も判断の材料にすることができる。なお、上記の結晶性の評価は、遷移金属源だけではなく、一次粒子、又は二次粒子の結晶性の評価の際にも適用することができる。 In addition, it is preferable that the transition metal M source has high crystallinity. For example, it is preferable that the transition metal source has single crystal grains. The crystallinity of the transition metal source can be evaluated, for example, from a TEM (transmission electron microscope) image, a STEM (scanning transmission electron microscope) image, a HAADF-STEM (high-angle scattering annular dark-field scanning transmission electron microscope) image, an ABF-STEM (annular bright-field scanning transmission electron microscope) image, etc. In addition, X-ray diffraction (XRD), electron beam diffraction, neutron beam diffraction, etc. can also be used to evaluate the crystallinity of the transition metal source. Note that the above crystallinity evaluation can be applied not only to the transition metal source, but also to the evaluation of the crystallinity of primary particles or secondary particles.
鉄（ＩＩ）化合物の代表例としては、塩化鉄四水和物（ＦｅＣｌ２・４Ｈ２Ｏ）、硫酸鉄七水和物（ＦｅＳＯ４・７Ｈ２Ｏ）、酢酸鉄（Ｆｅ（ＣＨ３ＣＯＯ）２）等がある。 Representative examples of iron (II) compounds include iron chloride tetrahydrate (FeCl 2 .4H 2 O), iron sulfate heptahydrate (FeSO 4 .7H 2 O), and iron acetate (Fe(CH 3 COO) 2 ).
マンガン（ＩＩ）化合物の代表例としては、塩化マンガン四水和物（ＭｎＣｌ２・４Ｈ２Ｏ）、硫酸マンガン一水和物（ＭｎＳＯ４・Ｈ２Ｏ）、酢酸マンガン四水和物（Ｍｎ（ＣＨ３ＣＯＯ）２・４Ｈ２Ｏ）等がある。 Representative examples of manganese (II) compounds include manganese chloride tetrahydrate ( MnCl2.4H2O ) , manganese sulfate monohydrate ( MnSO4.H2O ), manganese acetate tetrahydrate (Mn( CH3COO ) 2.4H2O ) , and the like.
コバルト（ＩＩ）化合物の代表例としては、塩化コバルト六水和物（ＣｏＣｌ２・６Ｈ２Ｏ）、硫酸コバルト七水和物（ＣｏＳＯ４・７Ｈ２Ｏ）、酢酸コバルト四水和物（Ｃｏ（ＣＨ３ＣＯＯ）２・４Ｈ２Ｏ）等がある。 Representative examples of cobalt (II) compounds include cobalt chloride hexahydrate ( CoCl2.6H2O ) , cobalt sulfate heptahydrate ( CoSO4.7H2O ), and cobalt acetate tetrahydrate ( Co ( CH3COO ) 2.4H2O ).
ニッケル（ＩＩ）化合物の代表例としては、塩化ニッケル六水和物（ＮｉＣｌ２・６Ｈ２Ｏ）、硫酸ニッケル六水和物（ＮｉＳＯ４・６Ｈ２Ｏ）、酢酸ニッケル四水和物（Ｎｉ（ＣＨ３ＣＯＯ）２・４Ｈ２Ｏ）等がある。 Representative examples of nickel (II) compounds include nickel chloride hexahydrate ( NiCl2.6H2O ), nickel sulfate hexahydrate ( NiSO4.6H2O ), nickel acetate tetrahydrate (Ni( CH3COO ) 2.4H2O ) , and the like.
なお、ステップＳ４２において、遷移金属Ｍ源８２２として、上記化合物を水溶液として用意してもよい。水溶液として用意する場合、用いる水として、好ましくは比抵抗が１ＭΩ・ｃｍ以上、より好ましくは比抵抗が１０ＭΩ・ｃｍ以上、さらに好ましくは比抵抗が１５ＭΩ・ｃｍ以上の、不純物が少ない純水であることが望ましい。 In step S42, the above compound may be prepared as an aqueous solution as the transition metal M source 822. When preparing the compound as an aqueous solution, it is desirable that the water used be pure water with few impurities, preferably with a resistivity of 1 MΩ·cm or more, more preferably with a resistivity of 10 MΩ·cm or more, and even more preferably with a resistivity of 15 MΩ·cm or more.
次に、図１５のステップＳ４１として、ステップＳ４１の混合物８２１と、遷移金属Ｍ源８２２と、を混合しステップＳ９２の混合物８３１を得る。 Next, in step S41 of FIG. 15, the mixture 821 of step S41 is mixed with the transition metal M source 822 to obtain the mixture 831 of step S92.
ここでステップＳ４１において、溶媒を加えてステップＳ９２の混合物８３１の濃度を下げることができる。例えば、ステップＳ４１において、ステップＳ４１の混合物８２１と、遷移金属Ｍ源８２２と、溶媒と、を混合し、ステップＳ９２の混合物８３１を作製することができる。 Here, in step S41, a solvent can be added to reduce the concentration of mixture 831 in step S92. For example, in step S41, mixture 821 in step S41, transition metal M source 822, and a solvent can be mixed to produce mixture 831 in step S92.
次に、図１５のステップＳ９３において、ステップＳ９２の混合物８３１をオートクレーブ等の耐熱耐圧容器に入れたのち、温度を１００℃以上３５０℃以下、より好ましくは１００℃より大きく２００℃未満、圧力を０．１１ＭＰａ以上１００ＭＰａ以下、より好ましくは０．１１ＭＰａ以上２ＭＰａ以下とし、０．５時間以上２４時間以下、より好ましくは１時間以上１０時間以下、さらに好ましくは１時間以上５時間未満、の加熱をした後、冷却する。続いて、ステップＳ９４において、耐熱耐圧容器内の溶液を濾過し、水で洗浄する。次に、ステップＳ９５において、乾燥した後に、回収し、ステップＳ９６の正極活物質９０を得る。正極活物質９０は複合酸化物と記すことができる。 Next, in step S93 of FIG. 15, the mixture 831 from step S92 is placed in a heat-resistant and pressure-resistant container such as an autoclave, and then heated at a temperature of 100° C. or more and 350° C. or less, more preferably more than 100° C. and less than 200° C., and at a pressure of 0.11 MPa or more and 100 MPa or less, more preferably 0.11 MPa or more and 2 MPa or less, for 0.5 hours or more and 24 hours or less, more preferably 1 hour or more and 10 hours or less, and even more preferably 1 hour or more and less than 5 hours, and then cooled. Next, in step S94, the solution in the heat-resistant and pressure-resistant container is filtered and washed with water. Next, in step S95, the mixture is dried and then recovered to obtain the positive electrode active material 90 in step S96. The positive electrode active material 90 can be described as a composite oxide.
得られた正極活物質９０はＬｉＭＰＯ４（Ｍは、Ｆｅ（ＩＩ），Ｎｉ（ＩＩ），Ｃｏ（ＩＩ），Ｍｎ（ＩＩ）の一以上）と記すことができ、具体的な正極活物質９０は、ＬｉＦｅＰＯ４（ＬＦＰ）、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４、ＬｉＭｎＰＯ４、ＬｉＦｅａＮｉｂＰＯ４、ＬｉＦｅａＣｏｂＰＯ４、ＬｉＦｅａＭｎｂＰＯ４、ＬｉＮｉａＣｏｂＰＯ４、ＬｉＮｉａＭｎｂＰＯ４（ａ＋ｂは１以下、０＜ａ＜１、０＜ｂ＜１）、ＬｉＦｅｃＮｉｄＣｏｅＰＯ４、ＬｉＦｅｃＮｉｄＭｎｅＰＯ４、ＬｉＮｉｃＣｏｄＭｎｅＰＯ４（ｃ＋ｄ＋ｅは１以下、０＜ｃ＜１、０＜ｄ＜１、０＜ｅ＜１）、ＬｉＦｅｆＮｉｇＣｏｈＭｎｉＰＯ４（ｆ＋ｇ＋ｈ＋ｉは１以下、０＜ｆ＜１、０＜ｇ＜１、０＜ｈ＜１、０＜ｉ＜１）等が挙げられる。上記のうちＬＦＰは安全性が高く、電気自動車の活物質に好適である。またＬＬＦＰは安価であり、電気自動車の活物質に好適である。 The obtained positive electrode active material 90 can be expressed as LiMPO 4 (M is one or more of Fe(II), Ni(II), Co(II), and Mn(II)), and specific positive electrode active materials 90 include LiFePO 4 (LFP), LiNiPO 4 , LiCoPO 4 , LiMnPO 4 , LiFe a Ni b PO 4 , LiFe a Co b PO 4 , LiFe a Mn b PO 4 , LiNi a Co b PO 4 , LiNi a Mn b PO 4 (a+b is 1 or less, 0<a<1, 0<b<1), LiFe c Ni d Co e PO 4 , LiFe c Ni d Mn Examples include LiFe f Nig Co h Mn i PO 4 (c+d+e is 1 or less, 0<c<1, 0<d<1, 0<e<1), LiFe f Nig Co h Mn i PO 4 (f+g+h+i is 1 or less, 0<f<1, 0<g<1, 0<h<1, 0<i<1), etc. Of the above, LFP is highly safe and is suitable as an active material for electric vehicles. LLFP is also inexpensive and is suitable as an active material for electric vehicles.
本実施の形態により得られる複合酸化物は結晶性が高く好ましい。結晶性が高い複合酸化物はサイクル劣化等を抑制することができる。当該複合酸化物は単結晶粒をなすこともある。 The composite oxide obtained in this embodiment has high crystallinity and is therefore preferable. A composite oxide with high crystallinity can suppress cycle deterioration and the like. The composite oxide may also form single crystal grains.
正極活物質９０に対して例えばＸＲＤ、あるいは電子線回折等の結晶解析を行うことにより、結晶構造を特定することができる。例えば、オリビン型の結晶構造を有するＬｉＭＰＯ４は、空間群Ｐｎｍａに属すると特定される。 The crystal structure can be identified by performing crystal analysis such as XRD or electron beam diffraction on the positive electrode active material 90. For example, LiMPO4 having an olivine type crystal structure is identified as belonging to the space group Pnma.
以上のとおり、本実施の形態では、上記実施の形態に適用できる正極活物質を水熱法により作製する例を示したが、上記の例に限定解釈されるものではない。 As described above, in this embodiment, an example of producing a positive electrode active material that can be applied to the above embodiment by a hydrothermal method is shown, but the interpretation is not limited to the above example.
本実施の形態は、他の実施の形態と適宜組み合わせて用いることができる。 This embodiment can be used in appropriate combination with other embodiments.
（実施の形態５）
本実施の形態では、上記実施の形態に適用できる正極活物質の製造方法３について説明する。具体的には正極活物質を液相法により製造する方法について、図１６等を用いて説明する。本実施の形態で示す正極活物質の製造方法３は、断りのない限り、第１のバッテリ１０１ａ、及び／又は第２のバッテリ１０１ｂに適用できる。 (Embodiment 5)
In this embodiment, a method for manufacturing a positive electrode active material 3 that can be applied to the above-mentioned embodiment will be described. Specifically, a method for manufacturing a positive electrode active material by a liquid phase method will be described with reference to Fig. 16 and the like. Unless otherwise specified, the method for manufacturing a positive electrode active material 3 shown in this embodiment can be applied to the first battery 101a and/or the second battery 101b.
［正極活物質の製造方法３］
図１６のステップＳ３０ａにおいて、リチウムを含む溶液８０６を用意する。また、ステップＳ３０ｂにおいて、リンを含む溶液８０７を用意する。 [Method of producing positive electrode active material 3]
16, a solution 806 containing lithium is prepared, and in step S30b, a solution 807 containing phosphorus is prepared.
リチウムを含む溶液８０６は、リチウム化合物を溶媒に溶解することで作製することができる。リチウム化合物として、水酸化リチウム一水和物（ＬｉＯＨ・Ｈ２Ｏ）、塩化リチウム（ＬｉＣｌ）、炭酸リチウム（Ｌｉ２ＣＯ３）、酢酸リチウム（ＣＨ３ＣＯＯＬｉ）、シュウ酸リチウム（（ＣＯＯＬｉ）２）、のいずれか一以上を用いることができる。リチウム化合物を溶解する溶媒としては水がある。溶媒として水を用いる場合、好ましくは比抵抗が１ＭΩ・ｃｍ以上、より好ましくは比抵抗が１０ＭΩ・ｃｍ以上、さらに好ましくは比抵抗が１５ＭΩ・ｃｍ以上の、不純物が少ない純水であることが望ましい。高純度の材料を用いることで、二次電池の容量を高めること、及び／又は二次電池の信頼性を高めることができる。 The solution 806 containing lithium can be prepared by dissolving a lithium compound in a solvent. As the lithium compound, any one or more of lithium hydroxide monohydrate (LiOH.H 2 O), lithium chloride (LiCl), lithium carbonate (Li 2 CO 3 ), lithium acetate (CH 3 COOLi), and lithium oxalate ((COOLi) 2 ) can be used. Water is an example of a solvent for dissolving the lithium compound. When water is used as the solvent, it is desirable that the water is pure water with a low impurity content and preferably has a resistivity of 1 MΩ·cm or more, more preferably a resistivity of 10 MΩ·cm or more, and even more preferably a resistivity of 15 MΩ·cm or more. By using a high-purity material, the capacity of the secondary battery can be increased and/or the reliability of the secondary battery can be increased.
リンを含む溶液８０７は、リン化合物を溶媒に溶解することで作製することができる。リン化合物として、オルトリン酸（Ｈ３ＰＯ４）等のリン酸、又は、リン酸水素二アンモニウム（（ＮＨ４）２ＨＰＯ４）、もしくはリン酸二水素アンモニウム（ＮＨ４Ｈ２ＰＯ４）等のリン酸水素アンモニウム、のいずれか一以上を用いることができる。リン化合物を溶解する溶媒としては水がある。溶媒として水を用いる場合、好ましくは比抵抗が１ＭΩ・ｃｍ以上、より好ましくは比抵抗が１０ＭΩ・ｃｍ以上、さらに好ましくは比抵抗が１５ＭΩ・ｃｍ以上の、不純物が少ない純水であることが望ましい。高純度の材料を用いることで、電池セルの容量を高めること、又は電池セルの信頼性を高めることができる。 The solution 807 containing phosphorus can be prepared by dissolving a phosphorus compound in a solvent. As the phosphorus compound, one or more of phosphoric acid such as orthophosphoric acid (H 3 PO 4 ) or ammonium hydrogen phosphate such as diammonium hydrogen phosphate ((NH 4 ) 2 HPO 4 ) or ammonium dihydrogen phosphate (NH 4 H 2 PO 4 ) can be used. Water is an example of a solvent for dissolving the phosphorus compound. When water is used as the solvent, it is desirable that the water be pure water with few impurities, preferably with a resistivity of 1 MΩ·cm or more, more preferably with a resistivity of 10 MΩ·cm or more, and even more preferably with a resistivity of 15 MΩ·cm or more. By using a high-purity material, the capacity of the battery cell can be increased, or the reliability of the battery cell can be increased.
次に、図１６のステップＳ３１として、リチウムを含む溶液８０６と、リンを含む溶液８０７と、を混合し、ステップＳ３２の混合物８１１を得る。ステップＳ３１の混合は、大気、不活性ガス、等の雰囲気下で行うことができる。不活性ガスとして例えば窒素を用いればよい。ここでは一例として、大気雰囲気下で、ステップＳ３０ａで用意したリチウムを含む溶液８０６と、ステップＳ３０ｂで用意したリンを含む溶液８０７と、を混合する。 Next, in step S31 of FIG. 16, a solution 806 containing lithium and a solution 807 containing phosphorus are mixed to obtain a mixture 811 in step S32. The mixing in step S31 can be performed in an atmosphere such as air or an inert gas. For example, nitrogen can be used as the inert gas. Here, as an example, the solution 806 containing lithium prepared in step S30a and the solution 807 containing phosphorus prepared in step S30b are mixed in an air atmosphere.
なお、リチウムを含む溶液８０６及びリンを含む溶液８０７を混合し、ステップＳ３２の混合物８１１を形成する代わりに、Ｌｉ３ＰＯ４，Ｌｉ２ＨＰＯ４，ＬｉＨ２ＰＯ４等、のリンとリチウムを有する化合物を用意し、溶媒に加えてステップＳ３２の混合物８１１を形成してもよい。 Note that, instead of mixing the solution 806 containing lithium and the solution 807 containing phosphorus to form the mixture 811 in step S32, a compound containing phosphorus and lithium, such as Li3PO4 , Li2HPO4 , or LiH2PO4 , may be prepared and added to a solvent to form the mixture 811 in step S32.
次に、図１６のステップＳ３３において、遷移金属Ｍを含む溶液８１３を用意する。 Next, in step S33 of FIG. 16, a solution 813 containing a transition metal M is prepared.
遷移金属Ｍを含む溶液８１３は、遷移金属Ｍ化合物を溶媒に溶解することで作製することができる。遷移金属Ｍ化合物として、鉄（ＩＩ）化合物、マンガン（ＩＩ）化合物、コバルト（ＩＩ）化合物、及びニッケル（ＩＩ）化合物（以下、Ｍ（ＩＩ）化合物と示す。）の一以上を用いることができる。遷移金属Ｍ化合物を溶解する溶媒としては水がある。溶媒として水を用いる場合、好ましくは比抵抗が１ＭΩ・ｃｍ以上、より好ましくは比抵抗が１０ＭΩ・ｃｍ以上、さらに好ましくは比抵抗が１５ＭΩ・ｃｍ以上の、不純物が少ない純水であることが望ましい。高純度の材料を用いることで、電池セルの容量を高めること、又は電池セルの信頼性を高めることができる。 The solution 813 containing the transition metal M can be prepared by dissolving the transition metal M compound in a solvent. As the transition metal M compound, one or more of an iron (II) compound, a manganese (II) compound, a cobalt (II) compound, and a nickel (II) compound (hereinafter referred to as an M (II) compound) can be used. An example of a solvent for dissolving the transition metal M compound is water. When using water as the solvent, it is desirable to use pure water with few impurities, preferably with a resistivity of 1 MΩ·cm or more, more preferably with a resistivity of 10 MΩ·cm or more, and even more preferably with a resistivity of 15 MΩ·cm or more. By using a high-purity material, it is possible to increase the capacity of the battery cell or increase the reliability of the battery cell.
なお、合成の際に用いる遷移金属Ｍ化合物としては、高純度の材料を用いると好ましい。具体的には、当該材料の純度としては、３Ｎ（９９．９％）以上、好ましくは４Ｎ（９９．９９％）以上、より好ましくは４Ｎ５（９９．９９５％）以上、さらに好ましくは５Ｎ（９９．９９９％）以上である。高純度の材料を用いることで、電池セルの容量を高めること、又は電池セルの信頼性を高めることができる。 It is preferable to use a high-purity material as the transition metal M compound used in the synthesis. Specifically, the purity of the material is 3N (99.9%) or more, preferably 4N (99.99%) or more, more preferably 4N5 (99.995%) or more, and even more preferably 5N (99.999%) or more. By using a high-purity material, it is possible to increase the capacity of the battery cell or improve the reliability of the battery cell.
加えて、このときの遷移金属Ｍ化合物の結晶性が高いと好適である。例えば、遷移金属化合物は、単結晶粒を有すると好適である。遷移金属化合物の結晶性の評価としては、例えば、ＴＥＭ像、ＳＴＥＭ像、ＨＡＡＤＦ−ＳＴＥＭ像、ＡＢＦ−ＳＴＥＭ像等から判断することができる。また、遷移金属Ｍ化合物の結晶性の評価としては、Ｘ線回折（ＸＲＤ）、電子線回折、中性子線回折等も判断の材料にすることができる。なお、上記の結晶性の評価は、遷移金属Ｍ化合物だけではなく、一次粒子、又は二次粒子の結晶性の評価の際にも適用することができる。 In addition, it is preferable that the transition metal M compound has high crystallinity. For example, it is preferable that the transition metal compound has single crystal grains. The crystallinity of the transition metal compound can be evaluated, for example, from a TEM image, a STEM image, a HAADF-STEM image, an ABF-STEM image, etc. Furthermore, the crystallinity of the transition metal M compound can also be evaluated using X-ray diffraction (XRD), electron beam diffraction, neutron beam diffraction, etc. Note that the above crystallinity evaluation can be applied not only to the transition metal M compound, but also to the evaluation of the crystallinity of primary particles or secondary particles.
鉄（ＩＩ）化合物、マンガン（ＩＩ）化合物、コバルト（ＩＩ）化合物の、又はニッケル（ＩＩ）化合物の代表例としては、本実施の形態で説明した鉄（ＩＩ）化合物、マンガン（ＩＩ）化合物、コバルト（ＩＩ）化合物、又はニッケル（ＩＩ）化合物の代表例を用いることができる。 As representative examples of iron (II) compounds, manganese (II) compounds, cobalt (II) compounds, or nickel (II) compounds, the representative examples of iron (II) compounds, manganese (II) compounds, cobalt (II) compounds, or nickel (II) compounds described in this embodiment can be used.
次に、図１６のステップ３５として、ステップＳ３２の混合物８１１と、遷移金属Ｍを含む溶液８１３と、を混合しステップＳ４１の混合物８２３を得る。 Next, in step 35 of FIG. 16, the mixture 811 of step S32 is mixed with a solution 813 containing a transition metal M to obtain a mixture 823 of step S41.
ここで、後述する正極活物質９０として得られることが好ましい複合酸化物のリチウム、遷移金属Ｍ、及びリンの原子数比をｘ：ｙ：ｚとする。ＬｉＭＰＯ４を得るためには例えばｘ：ｙ：ｚ＝１：１：１とすればよい。 Here, the atomic ratio of lithium, transition metal M, and phosphorus in a composite oxide preferably obtained as a positive electrode active material 90 described later is defined as x:y:z. In order to obtain LiMPO4, for example, x:y:z=1:1:1 may be used.
図１６のステップＳ３５の混合の方法として、容器に入れたステップＳ３２の混合物８１１に対して、遷移金属Ｍを含む溶液８１３を少量ずつ滴下して、ステップＳ４１の混合物８２３を作製することができる。混合において、容器内の溶液及び混合に用いる溶液は、撹拌していることが望ましく、また、Ｎ２バブリングによって溶存酸素を除去することが望ましい。 16, a solution 813 containing the transition metal M can be dropped little by little into the mixture 811 of step S32 placed in a container to produce a mixture 823 of step S41. In mixing, it is preferable to stir the solution in the container and the solution used for mixing, and it is also preferable to remove dissolved oxygen by N2 bubbling.
又は、図１６のステップＳ３５の混合の方法として、容器に入れた遷移金属Ｍを含む溶液８１３に対して、ステップＳ３２の混合物８１１を少量ずつ滴下して、ステップＳ４１の混合物８２３を作製することができる。混合において、容器内の溶液及び混合に用いる溶液は、撹拌していることが望ましく、また、Ｎ２バブリングによって溶存酸素を除去することが望ましい。 16, the mixture 811 of step S32 can be added dropwise in small amounts to a solution 813 containing the transition metal M placed in a container to produce a mixture 823 of step S41. In mixing, it is preferable to stir the solution in the container and the solution used for mixing, and it is also preferable to remove dissolved oxygen by N2 bubbling.
ここでステップＳ３５において、溶媒を加えてステップＳ４１の混合物８２３の濃度を調整することができる。例えば、ステップＳ３５において、ステップＳ３２の混合物８１１と、遷移金属Ｍを含む溶液８１３と、溶媒と、を混合し、ステップＳ４１の混合物８２３を作製することができる。溶媒として水を用いる場合、好ましくは比抵抗が１ＭΩ・ｃｍ以上、より好ましくは比抵抗が１０ＭΩ・ｃｍ以上、さらに好ましくは比抵抗が１５ＭΩ・ｃｍ以上の、不純物が少ない純水であることが望ましい。 Here, in step S35, a solvent can be added to adjust the concentration of the mixture 823 of step S41. For example, in step S35, the mixture 811 of step S32, the solution 813 containing the transition metal M, and a solvent can be mixed to produce the mixture 823 of step S41. When water is used as the solvent, it is desirable that it be pure water with few impurities, preferably with a resistivity of 1 MΩ·cm or more, more preferably with a resistivity of 10 MΩ·cm or more, and even more preferably with a resistivity of 15 MΩ·cm or more.
次に、図１６のステップＳ９３において、ステップＳ４１の混合物８２３をオートクレーブ等の耐熱耐圧容器に入れたのち、温度を１００℃以上３５０℃以下、より好ましくは１００℃より大きく２００℃未満、圧力を０．１１ＭＰａ以上１００ＭＰａ以下、より好ましくは０．１１ＭＰａ以上２ＭＰａ以下とし、０．５時間以上２４時間以下、より好ましくは１時間以上１０時間以下、さらに好ましくは１時間以上５時間未満、の加熱をした後、冷却する。続いて、ステップＳ９４において、耐熱耐圧容器内の溶液を濾過し、水で洗浄する。次に、ステップＳ９５において、乾燥した後に、回収し、ステップＳ９６の正極活物質９０を得る。正極活物質９０は複合酸化物と記すことができる。 Next, in step S93 of FIG. 16, the mixture 823 from step S41 is placed in a heat-resistant and pressure-resistant container such as an autoclave, and then heated at a temperature of 100° C. or more and 350° C. or less, more preferably more than 100° C. and less than 200° C., and at a pressure of 0.11 MPa or more and 100 MPa or less, more preferably 0.11 MPa or more and 2 MPa or less, for 0.5 hours or more and 24 hours or less, more preferably 1 hour or more and 10 hours or less, and even more preferably 1 hour or more and less than 5 hours, and then cooled. Next, in step S94, the solution in the heat-resistant and pressure-resistant container is filtered and washed with water. Next, in step S95, the mixture is dried and then recovered to obtain the positive electrode active material 90 in step S96. The positive electrode active material 90 can be described as a composite oxide.
得られた正極活物質９０はＬｉＭＰＯ４（Ｍは、Ｆｅ（ＩＩ），Ｎｉ（ＩＩ），Ｃｏ（ＩＩ），Ｍｎ（ＩＩ）の一以上）と記すことができ、具体的な正極活物質９０は、ＬｉＦｅＰＯ４（ＬＦＰ）、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４、ＬｉＭｎＰＯ４、ＬｉＦｅａＮｉｂＰＯ４、ＬｉＦｅａＣｏｂＰＯ４、ＬｉＦｅａＭｎｂＰＯ４、ＬｉＮｉａＣｏｂＰＯ４、ＬｉＮｉａＭｎｂＰＯ４（ａ＋ｂは１以下、０＜ａ＜１、０＜ｂ＜１）、ＬｉＦｅｃＮｉｄＣｏｅＰＯ４、ＬｉＦｅｃＮｉｄＭｎｅＰＯ４、ＬｉＮｉｃＣｏｄＭｎｅＰＯ４（ｃ＋ｄ＋ｅは１以下、０＜ｃ＜１、０＜ｄ＜１、０＜ｅ＜１）、ＬｉＦｅｆＮｉｇＣｏｈＭｎｉＰＯ４（ｆ＋ｇ＋ｈ＋ｉは１以下、０＜ｆ＜１、０＜ｇ＜１、０＜ｈ＜１、０＜ｉ＜１）等が挙げられる。上記のうちＬＦＰは安全性が高く、電気自動車の活物質に好適である。またＬＦＰは安価であり、電気自動車の活物質に好適である。 The obtained positive electrode active material 90 can be expressed as LiMPO 4 (M is one or more of Fe(II), Ni(II), Co(II), and Mn(II)), and specific positive electrode active materials 90 include LiFePO 4 (LFP), LiNiPO 4 , LiCoPO 4 , LiMnPO 4 , LiFe a Ni b PO 4 , LiFe a Co b PO 4 , LiFe a Mn b PO 4 , LiNi a Co b PO 4 , LiNi a Mn b PO 4 (a+b is 1 or less, 0<a<1, 0<b<1), LiFe c Ni d Co e PO 4 , LiFe c Ni d Mn Examples of such active materials include LiFe f Nig Co h Mn i PO 4 ( c+d+e is 1 or less, 0<c<1, 0<d<1, 0<e<1), LiFe f Nig Co h Mn i PO 4 ( f+g+h+i is 1 or less, 0<f<1, 0<g<1, 0<h<1, 0<i<1), etc. Among the above, LFP is highly safe and is suitable as an active material for electric vehicles. LFP is also inexpensive and is suitable as an active material for electric vehicles.
本実施の形態により得られる複合酸化物は結晶性が高く好ましい。結晶性が高い複合酸化物はサイクル劣化等を抑制することができる。当該複合酸化物は単結晶粒をなすこともある。 The composite oxide obtained in this embodiment has high crystallinity and is therefore preferable. A composite oxide with high crystallinity can suppress cycle deterioration and the like. The composite oxide may also form single crystal grains.
正極活物質９０に対して例えばＸＲＤ、あるいは電子線回折等の結晶解析を行うことにより、結晶構造を特定することができる。例えば、オリビン型の結晶構造を有するＬｉＭＰＯ４は、空間群Ｐｎｍａに属すると特定される。 The crystal structure can be identified by performing crystal analysis such as XRD or electron beam diffraction on the positive electrode active material 90. For example, LiMPO4 having an olivine type crystal structure is identified as belonging to the space group Pnma.
以上のとおり、本実施の形態では、上記実施の形態に適用できる正極活物質を水熱法により作製する例を示したが、上記の例に限定解釈されるものではない。 As described above, in this embodiment, an example of producing a positive electrode active material that can be applied to the above embodiment by a hydrothermal method is shown, but the interpretation is not limited to the above example.
本実施の形態は、他の実施の形態と適宜組み合わせて用いることができる。 This embodiment can be used in appropriate combination with other embodiments.
（実施の形態６）
本実施の形態では、上記実施の形態に適用できる正極活物質の製造方法４について説明する。具体的には正極活物質を固相法により製造する方法について、図１７乃至図２０等を用いて説明する。本実施の形態で示す正極活物質の製造方法４は、断りのない限り、第１のバッテリ１０１ａ、及び／又は第２のバッテリ１０１ｂに適用できる。 (Embodiment 6)
In this embodiment, a method for manufacturing a positive electrode active material 4 that can be applied to the above-mentioned embodiment will be described. Specifically, a method for manufacturing a positive electrode active material by a solid phase method will be described with reference to Figs. 17 to 20 and the like. Unless otherwise specified, the method for manufacturing a positive electrode active material 4 shown in this embodiment can be applied to the first battery 101a and/or the second battery 101b.
［正極活物質の製造方法４］
初期加熱を経る正極活物質の作製方法４について、図１７Ａ乃至図１７Ｃを用いて説明する。 [Method of producing positive electrode active material 4]
Method 4 for preparing a positive electrode active material through initial heating will be described with reference to FIGS. 17A to 17C. FIG.
＜ステップＳ１１＞
図１７Ａに示すステップＳ１１では、出発材料であるリチウム及び遷移金属の材料として、それぞれリチウム源（Ｌｉ源）及びコバルト源（Ｃｏ源）を準備する。 <Step S11>
In step S11 shown in FIG. 17A, a lithium source (Li source) and a cobalt source (Co source) are prepared as starting materials, that is, lithium and transition metal materials, respectively.
リチウム源としては、リチウムを有する化合物を用いると好ましく、例えば炭酸リチウム、水酸化リチウム、硝酸リチウム、又はフッ化リチウム等を用いることができる。リチウム源は純度が高いと好ましく、例えば純度が９９．９９％以上の材料を用いるとよい。 As the lithium source, it is preferable to use a compound containing lithium, such as lithium carbonate, lithium hydroxide, lithium nitrate, or lithium fluoride. It is preferable that the lithium source has high purity, for example, a material with a purity of 99.99% or more.
コバルト源としては、コバルトを有する化合物を用いると好ましく、例えば酸化コバルト、水酸化コバルト等を用いることができる。 As the cobalt source, it is preferable to use a compound containing cobalt, such as cobalt oxide or cobalt hydroxide.
コバルト源は純度が高いと好ましく、例えば純度が３Ｎ（９９．９％）以上、好ましくは４Ｎ（９９．９９％）以上、より好ましくは４Ｎ５（９９．９９５％）以上、さらに好ましくは５Ｎ（９９．９９９％）以上の材料を用いるとよい。高純度の材料を用いることで、正極活物質の不純物を制御することができる。その結果、二次電池の容量が高まり、及び／又は二次電池の信頼性が向上する。 The cobalt source is preferably of high purity, for example, a material with a purity of 3N (99.9%) or more, preferably 4N (99.99%) or more, more preferably 4N5 (99.995%) or more, and even more preferably 5N (99.999%) or more may be used. By using a high purity material, impurities in the positive electrode active material can be controlled. As a result, the capacity of the secondary battery is increased and/or the reliability of the secondary battery is improved.
加えて、コバルト源の結晶性が高いと好ましく、例えば単結晶粒を有するとよい。コバルト源の結晶性の評価としては、ＴＥＭ像、ＳＴＥＭ像、ＨＡＡＤＦ−ＳＴＥＭ像、ＡＢＦ−ＳＴＥＭ像等による評価、又はＸＲＤ、電子線回折、中性子線回折等の評価がある。なお、上記の結晶性の評価に関する手法は、コバルト源だけではなく、その他の結晶性の評価にも適用することができる。 In addition, it is preferable that the cobalt source has high crystallinity, for example, single crystal grains. The crystallinity of the cobalt source can be evaluated using TEM images, STEM images, HAADF-STEM images, ABF-STEM images, etc., or evaluation using XRD, electron beam diffraction, neutron beam diffraction, etc. Note that the above-mentioned methods for evaluating crystallinity can be applied not only to the evaluation of cobalt sources, but also to the evaluation of other crystallinity.
＜ステップＳ１２＞
次に、図１７Ａに示すステップＳ１２として、リチウム源及びコバルト源を粉砕及び混合して、混合材料を作製する。粉砕及び混合は、乾式又は湿式で行うことができる。湿式は、より小さく解砕することができるため好ましい。湿式で行う場合は、溶媒を準備する。溶媒としてはアセトン等のケトン、エタノール及びイソプロパノール等のアルコール、エーテル、ジオキサン、アセトニトリル、Ｎ−メチル−２−ピロリドン（ＮＭＰ）等を用いることができる。リチウムと反応が起こりにくい、非プロトン性溶媒を用いることがより好ましい。本実施の形態では、純度が９９．５％以上の脱水アセトンを用いることとする。水分含有量を１０ｐｐｍ以下まで抑えた、純度が９９．５％以上の脱水アセトンにリチウム源及びコバルト源を混合して、粉砕及び混合を行うと好適である。上記のような純度の脱水アセトンを用いることで、混入しうる不純物を低減することができる。 <Step S12>
Next, in step S12 shown in FIG. 17A, the lithium source and the cobalt source are pulverized and mixed to prepare a mixed material. The pulverization and mixing can be performed in a dry or wet manner. The wet method is preferable because it can be crushed into smaller pieces. When performing the wet method, a solvent is prepared. As the solvent, ketones such as acetone, alcohols such as ethanol and isopropanol, ether, dioxane, acetonitrile, N-methyl-2-pyrrolidone (NMP), etc. can be used. It is more preferable to use an aprotic solvent that is less likely to react with lithium. In this embodiment, dehydrated acetone with a purity of 99.5% or more is used. It is preferable to mix the lithium source and the cobalt source with dehydrated acetone with a purity of 99.5% or more, in which the moisture content is suppressed to 10 ppm or less, and then pulverize and mix them. By using dehydrated acetone with the above-mentioned purity, it is possible to reduce impurities that may be mixed in.
粉砕及び混合の手段には、ボールミル、又はビーズミル等を用いることができる。ボールミルを用いる場合は、メディアとして酸化アルミニウムボール又は酸化ジルコニウムボールを用いるとよい。酸化ジルコニウムボールは不純物の排出が少なく好ましい。また、ボールミル、又はビーズミル等を用いる場合、メディアからのコンタミネーションを抑制するために、周速を、１００ｍｍ／ｓ以上２０００ｍｍ／ｓ以下とするとよい。本実施の形態では、周速８３８ｍｍ／ｓ（回転数４００ｒｐｍ、ボールミルの直径４０ｍｍ）として実施する。 A ball mill, a bead mill, or the like can be used as a means for grinding and mixing. When using a ball mill, it is preferable to use aluminum oxide balls or zirconium oxide balls as the media. Zirconium oxide balls are preferable because they emit less impurities. Furthermore, when using a ball mill, a bead mill, or the like, it is preferable to set the peripheral speed to 100 mm/s or more and 2000 mm/s or less in order to suppress contamination from the media. In this embodiment, the peripheral speed is set to 838 mm/s (rotation speed 400 rpm, ball mill diameter 40 mm).
＜ステップＳ１３＞
次に、図１７Ａに示すステップＳ１３として、上記混合材料を加熱する。加熱は、８００℃以上１１００℃以下で行うことが好ましく、９００℃以上１０００℃以下で行うことがより好ましく、９５０℃程度がさらに好ましい。温度が低すぎると、リチウム源及びコバルト源の分解及び溶融が不十分となるおそれがある。一方温度が高すぎると、リチウム源からリチウムが蒸散する、及び／又はコバルトが過剰に還元される、などが原因となり欠陥が生じるおそれがある。例えばコバルトが３価から２価へ変化し、酸素欠陥などが誘発されることがある。 <Step S13>
Next, in step S13 shown in FIG. 17A, the mixed material is heated. The heating is preferably performed at 800° C. or more and 1100° C. or less, more preferably at 900° C. or more and 1000° C. or less, and even more preferably at about 950° C. If the temperature is too low, the decomposition and melting of the lithium source and the cobalt source may be insufficient. On the other hand, if the temperature is too high, defects may occur due to lithium transpiration from the lithium source and/or cobalt being excessively reduced. For example, cobalt may change from trivalent to divalent, inducing oxygen defects, etc.
加熱時間は短すぎるとコバルト酸リチウムが合成されないが、長すぎると生産性が低下する。例えば加熱時間は１時間以上１００時間以下とするとよく、２時間以上２０時間以下とすることがさらに好ましい。 If the heating time is too short, lithium cobalt oxide will not be synthesized, but if it is too long, productivity will decrease. For example, the heating time should be between 1 hour and 100 hours, and more preferably between 2 hours and 20 hours.
昇温レートは、加熱温度の到達温度によるが、８０℃／時間以上２５０℃／時間以下がよい。例えば１０００℃で１０時間加熱する場合、昇温レートは２００℃／時間とするとよい。 The rate of temperature rise depends on the heating temperature reached, but should be between 80°C/hour and 250°C/hour. For example, if heating at 1000°C for 10 hours, the rate of temperature rise should be 200°C/hour.
加熱は、乾燥空気等の水が少ない雰囲気で行うことが好ましく、例えば露点が−５０℃以下、より好ましくは露点が−８０℃以下の雰囲気がよい。本実施の形態においては、露点−９３℃の雰囲気にて、加熱を行うこととする。また材料中に混入しうる不純物を抑制するためには、加熱雰囲気におけるＣＨ４、ＣＯ、ＣＯ２、及びＨ２等の不純物濃度が、それぞれ５ｐｐｂ（ｐａｒｔｓ　ｐｅｒ　ｂｉｌｌｉｏｎ）以下にするとよい。 The heating is preferably performed in an atmosphere with little water, such as dry air, for example, an atmosphere with a dew point of −50° C. or less, more preferably an atmosphere with a dew point of −80° C. or less. In this embodiment, the heating is performed in an atmosphere with a dew point of −93° C. In order to suppress impurities that may be mixed into the material, the impurity concentrations of CH 4 , CO, CO 2 , H 2 , and the like in the heating atmosphere should each be 5 ppb (parts per billion) or less.
加熱雰囲気として、酸素を有する雰囲気が好ましい。例えば、反応室に乾燥空気を導入し続ける方法がある。この場合、乾燥空気の流量は１０Ｌ／分とすることが好ましい。酸素を反応室へ導入し続け、酸素が反応室内を流れている方法をフローと呼ぶ。 The heating atmosphere is preferably an atmosphere containing oxygen. For example, there is a method of continuously introducing dry air into the reaction chamber. In this case, the flow rate of the dry air is preferably 10 L/min. The method of continuously introducing oxygen into the reaction chamber and having oxygen flow through the reaction chamber is called flow.
加熱雰囲気を、酸素を有する雰囲気とする場合、フローさせないやり方でもよい。例えば反応室を減圧してから酸素を充填し（パージし、といってもよい）、当該酸素が反応室から出入りしないようにする方法でもよい。例えば反応室を差圧系が−９７０ｈＰａとなるまで減圧してから、５０ｈＰａまで酸素を充填すればよい。 When the heating atmosphere is an atmosphere containing oxygen, a method that does not allow flow may be used. For example, the reaction chamber may be depressurized and then filled with oxygen (or purged) to prevent the oxygen from entering or leaving the reaction chamber. For example, the reaction chamber may be depressurized until the differential pressure system reaches -970 hPa, and then filled with oxygen to 50 hPa.
加熱後の冷却は自然放冷でよいが、規定温度から室温までの降温時間が１０時間以上５０時間以下に収まると好ましく、例えば８０℃／時間以上２５０℃／時間以下がよく、１８０℃／時間以上２１０℃／時間以下がより好ましい。ただし、必ずしも室温までの冷却は要せず、次のステップが許容する温度まで冷却されればよい。 After heating, the material can be allowed to cool naturally, but it is preferable that the time required for the temperature to drop from the specified temperature to room temperature is within 10 to 50 hours, for example, 80°C/hour to 250°C/hour, and more preferably 180°C/hour to 210°C/hour. However, cooling to room temperature is not necessarily required, as long as the material is cooled to a temperature acceptable for the next step.
本工程の加熱は、ロータリーキルン又はローラーハースキルンによる加熱を行ってもよい。ロータリーキルンによる加熱は、連続式、バッチ式いずれの場合でも攪拌しながら加熱することができる。 The heating in this process may be performed using a rotary kiln or a roller hearth kiln. Heating using a rotary kiln can be performed while stirring, whether it is a continuous or batch type.
加熱の際に用いるるつぼは、酸化アルミニウムのるつぼが好ましい。酸化アルミニウムのるつぼは不純物を放出しにくい材質である。本実施の形態においては、純度が９９．９％の酸化アルミニウムのるつぼを用いる。るつぼには蓋を配して加熱すると好ましい。材料の揮発又は昇華を防ぐことができる。蓋を配するとは、本ステップの昇温時から降温時において、材料の揮発又は昇華を防ぐことができればよく、必ずしも蓋によりるつぼを密閉しなくともよい。例えば上述したように、反応室内に酸素を充填することで、るつぼを密閉しないで本ステップを実施することも可能になる。 The crucible used for heating is preferably an aluminum oxide crucible. An aluminum oxide crucible is a material that does not easily release impurities. In this embodiment, an aluminum oxide crucible with a purity of 99.9% is used. It is preferable to place a lid on the crucible when heating. This can prevent the material from volatilizing or sublimating. Placing a lid on the crucible means that it is possible to prevent the material from volatilizing or sublimating from the time the temperature is increased to the time the temperature is decreased in this step, and it is not necessary to seal the crucible with a lid. For example, as described above, by filling the reaction chamber with oxygen, it is possible to carry out this step without sealing the crucible.
また、るつぼは新品のものよりも、中古のものを用いることが好ましい。本明細書等において新品のるつぼとは、リチウム、遷移金属Ｍ、及び／又は添加元素を含む材料を入れて加熱する工程を経た回数が２回以下のものをいうこととする。また中古のるつぼとは、リチウム、遷移金属Ｍ及び／又は添加元素を含む材料を入れて加熱する工程を３回以上経たものをいうこととする。これは新品のるつぼを用いると、加熱の際にフッ化リチウムをはじめとする材料の一部がさやに吸収、拡散、移動及び／又は付着する恐れがあるためである。これらにより材料の一部が失われると、特に正極活物質の表層部の元素の分布が好ましい範囲にならない懸念が高まる。一方で中古のるつぼでは、この恐れが少ない。 In addition, it is preferable to use a used crucible rather than a new one. In this specification, a new crucible refers to one that has undergone the process of putting lithium, transition metal M, and/or materials containing additive elements into it and heating it two or less times. A used crucible refers to one that has undergone the process of putting lithium, transition metal M, and/or materials containing additive elements into it and heating it three or more times. This is because when a new crucible is used, there is a risk that some of the materials, including lithium fluoride, may be absorbed, diffused, moved, and/or attached to the sheath during heating. If some of the materials are lost as a result of this, there is an increased concern that the distribution of elements, particularly in the surface layer of the positive electrode active material, may not be within a preferred range. On the other hand, with a used crucible, this risk is less likely.
加熱が終わった後、必要に応じて粉砕し、さらにふるいを実施してもよい。加熱後の材料を回収する際に、るつぼから乳鉢へ移動させたのち回収してもよい。また、当該乳鉢は酸化アルミニウムの乳鉢又は酸化ジルコニウムの乳鉢を用いると好適である。酸化アルミニウムの乳鉢は不純物を放出しにくい材質である。具体的には、純度が９０％以上、好ましくは純度が９９％以上の酸化アルミニウムの乳鉢を用いる。なお、ステップＳ１３以外の後述の加熱の工程においても、ステップＳ１３と同等の加熱条件を適用できる。 After heating, the material may be crushed and sieved as necessary. When recovering the heated material, it may be transferred from the crucible to a mortar and then recovered. The mortar is preferably made of aluminum oxide or zirconium oxide. Aluminum oxide mortars are made of a material that does not easily release impurities. Specifically, an aluminum oxide mortar with a purity of 90% or more, preferably 99% or more, is used. Note that the same heating conditions as those in step S13 can be applied to the heating steps described below other than step S13.
＜ステップＳ１４＞
以上の工程により、図１７ＡのステップＳ１４に示すコバルト酸リチウム（ＬｉＣｏＯ２）を合成することができる。コバルト酸リチウムの粒径としてメディアン径（Ｄ５０）を用いる場合、相対的にメディアン径（Ｄ５０）の小さい正極活物質１００を得るには、コバルト酸リチウムを粉砕するとよい。 <Step S14>
By the above steps, lithium cobalt oxide (LiCoO 2 ) can be synthesized as shown in step S14 of Fig. 17A. When the median diameter (D50) is used as the particle diameter of lithium cobalt oxide, it is preferable to pulverize the lithium cobalt oxide in order to obtain a positive electrode active material 100 having a relatively small median diameter (D50).
ステップＳ１１乃至ステップＳ１４のように、固相法で複合酸化物を作製する例を示したが、共沈法で複合酸化物を作製してもよい。また水熱法で複合酸化物を作製してもよい。 In the example shown in steps S11 to S14, the composite oxide is produced by a solid phase method, but the composite oxide may also be produced by a coprecipitation method. The composite oxide may also be produced by a hydrothermal method.
＜ステップＳ１５＞
次に、図１７Ａに示すステップＳ１５として、コバルト酸リチウムを加熱する。コバルト酸リチウムに対する最初の加熱のため、ステップＳ１５の加熱を初期加熱と呼ぶことがある。又は以下に示すステップＳ２０の前に加熱するものであるため、予備加熱又は前処理と呼ぶことがある。本ステップに用いるるつぼ及び／又は蓋等は、ステップＳ１３で用いるものと同様である。初期加熱により次の効果が期待されるが、本発明の一態様である正極活物質を得るために初期加熱は必須ではない。 <Step S15>
Next, in step S15 shown in FIG. 17A, the lithium cobalt oxide is heated. Since this is the first heating of the lithium cobalt oxide, the heating in step S15 may be called initial heating. Or, since the heating is performed before step S20 described below, it may be called preheating or pretreatment. The crucible and/or lid used in this step are the same as those used in step S13. Although the following effects are expected from the initial heating, the initial heating is not essential to obtain the positive electrode active material which is one aspect of the present invention.
初期加熱により、上述したようにコバルト酸リチウムの表層部の一部からリチウムが脱離する。また内部の結晶性を高める効果が期待できる。またステップＳ１１等で準備したリチウム源及び／又はコバルト源には、不純物が混入していることがある。ステップＳ１４で完成したコバルト酸リチウムから不純物を低減させることが、初期加熱によって可能である。 As described above, initial heating causes lithium to be released from part of the surface layer of the lithium cobalt oxide. It is also expected to have the effect of increasing the internal crystallinity. Furthermore, impurities may be mixed into the lithium source and/or cobalt source prepared in step S11, etc. Initial heating makes it possible to reduce the impurities in the lithium cobalt oxide completed in step S14.
さらに初期加熱を経ることで、コバルト酸リチウムの表面がなめらかになる効果がある。表面がなめらかとは、凹凸が少なく、複合酸化物が全体的に丸みを帯び、さらに角部が丸みを帯びる様子をいう。さらに、表面へ付着した異物が少ない状態をなめらかと呼ぶ。異物は凹凸の要因となると考えられ、表面へ付着しない方が好ましい。 Furthermore, the initial heating has the effect of smoothing the surface of the lithium cobalt oxide. A smooth surface means that there are few irregularities, the composite oxide is generally rounded, and the corners are also rounded. Furthermore, a surface is called smooth when there is little foreign matter adhering to it. Foreign matter is thought to be a cause of unevenness, so it is preferable that it does not adhere to the surface.
この初期加熱には、リチウム源を用意しなくてよい。又は、添加元素源を用意しなくてよい。又は、融剤として機能する材料を用意しなくてよい。 For this initial heating, it is not necessary to prepare a lithium source, or a source of an additive element, or a material that functions as a flux.
本工程の加熱時間は短すぎると十分な効果が得られないが、長すぎると生産性が低下する。例えばステップＳ１３で説明した加熱条件から選択して実施することができる。当該加熱条件に補足すると、本工程の加熱温度は、複合酸化物の結晶構造を維持するため、ステップＳ１３の温度より低くするとよい。また本工程の加熱時間は、複合酸化物の結晶構造を維持するため、ステップＳ１３の時間より短くするとよい。例えば７００℃以上１０００℃以下の温度で、２時間以上２０時間以下の加熱を行うとよい。 If the heating time of this step is too short, sufficient effect will not be obtained, but if it is too long, productivity will decrease. For example, the heating conditions can be selected from those described in step S13. In addition to the heating conditions, the heating temperature of this step should be lower than the temperature of step S13 in order to maintain the crystal structure of the complex oxide. Furthermore, the heating time of this step should be shorter than the time of step S13 in order to maintain the crystal structure of the complex oxide. For example, heating should be performed at a temperature of 700°C to 1000°C for 2 hours to 20 hours.
また内部の結晶性を高める効果とは、例えばステップＳ１３で作製したコバルト酸リチウムが有する収縮差等に由来する歪み、ずれ等を緩和する効果である。 The effect of increasing the internal crystallinity is, for example, the effect of mitigating distortion, misalignment, etc. resulting from differences in shrinkage, etc., of the lithium cobalt oxide produced in step S13.
コバルト酸リチウムは、ステップＳ１３の加熱によって、コバルト酸リチウムの表面と内部に温度差が生じることがある。温度差が生じると収縮差が誘発されることがある。温度差により、表面と内部の流動性が異なるため、収縮差が生じるとも考えられる。収縮差に関連するエネルギーは、コバルト酸リチウムに内部応力の差を与えてしまう。内部応力の差は歪みとも称され、当該エネルギーを歪みエネルギーと呼ぶことがある。内部応力はステップＳ１５の初期加熱により除去され、別言すると歪みエネルギーはステップＳ１５の初期加熱により均質化されると考えられる。歪みエネルギーが均質化されると、コバルト酸リチウムの歪みが緩和される。これに伴い、コバルト酸リチウムの表面がなめらかになる可能性がある。表面が改善されたとも称する。別言すると、ステップＳ１５を経ると、コバルト酸リチウムに生じた収縮差が緩和され、複合酸化物の表面がなめらかになると考えられる。 The heating in step S13 may cause a temperature difference between the surface and the inside of the lithium cobalt oxide. The temperature difference may induce a shrinkage difference. It is also believed that the temperature difference causes the difference in fluidity between the surface and the inside, which leads to the shrinkage difference. The energy related to the shrinkage difference gives the lithium cobalt oxide a difference in internal stress. The internal stress difference is also called strain, and this energy is sometimes called strain energy. The internal stress is removed by the initial heating in step S15, or in other words, the strain energy is thought to be homogenized by the initial heating in step S15. When the strain energy is homogenized, the strain of the lithium cobalt oxide is alleviated. As a result, the surface of the lithium cobalt oxide may become smooth. This is also called the surface being improved. In other words, it is believed that the shrinkage difference caused in the lithium cobalt oxide is alleviated and the surface of the composite oxide becomes smooth after step S15.
また収縮差は上記コバルト酸リチウムにミクロなずれ、例えば結晶のずれを生じさせることがある。当該ずれを低減するためにも、本工程を実施するとよい。本工程を経ると、上記複合酸化物のずれを均一化させることが可能である。ずれが均一化されると、複合酸化物の表面がなめらかになる可能性がある。結晶粒の整列が行われたとも称する。別言すると、ステップＳ１５を経ると複合酸化物に生じた結晶等のずれが緩和され、複合酸化物の表面がなめらかになると考えられる。 Furthermore, the shrinkage difference may cause microscopic misalignment, such as crystal misalignment, in the lithium cobalt oxide. In order to reduce such misalignment, it is advisable to carry out this process. Through this process, it is possible to equalize the misalignment in the composite oxide. When the misalignment is equalized, the surface of the composite oxide may become smooth. This is also referred to as the alignment of crystal grains. In other words, it is believed that through step S15, the misalignment of crystals and the like that has occurred in the composite oxide is alleviated, and the surface of the composite oxide becomes smooth.
表面がなめらかなコバルト酸リチウムを正極活物質として用いると、二次電池として充放電した際の劣化が少なくなり、正極活物質の割れを防ぐことができる。 When lithium cobalt oxide, which has a smooth surface, is used as the positive electrode active material, it reduces deterioration during charging and discharging as a secondary battery and prevents cracking of the positive electrode active material.
なお、ステップＳ１４として、あらかじめ合成されたコバルト酸リチウムを用いてもよい。この場合、ステップＳ１１乃至ステップＳ１３を省略することができる。あらかじめ合成されたコバルト酸リチウムに対してステップＳ１５を実施することで、表面がなめらかなコバルト酸リチウムを得ることができる。 Note that in step S14, lithium cobalt oxide that has been synthesized in advance may be used. In this case, steps S11 to S13 can be omitted. By carrying out step S15 on lithium cobalt oxide that has been synthesized in advance, lithium cobalt oxide with a smooth surface can be obtained.
＜ステップＳ２０＞
次にステップＳ２０に示すように、初期加熱を経たコバルト酸リチウムに加える添加元素Ａを用意する。初期加熱を経たコバルト酸リチウムに添加元素Ａを加えると、添加元素Ａをムラなく添加することができる。よって、初期加熱後に添加元素Ａを添加する順が好ましい。添加元素Ａを用意するステップについて、図１７Ｂ、及び図１７Ｃを用いて説明する。 <Step S20>
Next, as shown in step S20, an additive element A to be added to the lithium cobalt oxide that has been initially heated is prepared. When the additive element A is added to the lithium cobalt oxide that has been initially heated, the additive element A can be added evenly. Therefore, it is preferable to add the additive element A after the initial heating. The step of preparing the additive element A will be described with reference to FIG. 17B and FIG. 17C.
＜ステップＳ２１＞
図１７Ｂに示すステップＳ２１では、コバルト酸リチウムに添加する添加元素Ａ源（Ａ源）を用意する。添加元素Ａ源と合わせて、リチウム源を準備してもよい。 <Step S21>
17B, a source of an additive element A (A source) to be added to lithium cobalt oxide is prepared. A lithium source may be prepared together with the additive element A source.
添加元素Ａとしては、先の実施の形態で説明した添加元素、例えば添加元素Ｘ及び添加元素Ｙを用いることができる。具体的にはマグネシウム、フッ素、ニッケル、アルミニウム、チタン、ジルコニウム、バナジウム、鉄、マンガン、クロム、ニオブ、ヒ素、亜鉛、ケイ素、硫黄、リン及びホウ素から選ばれた一又は二以上を用いることができる。また臭素、及びベリリウムから選ばれた一又は二を用いることもできる。 The additive element A can be any of the additive elements described in the previous embodiment, such as additive element X and additive element Y. Specifically, one or more elements selected from magnesium, fluorine, nickel, aluminum, titanium, zirconium, vanadium, iron, manganese, chromium, niobium, arsenic, zinc, silicon, sulfur, phosphorus, and boron can be used. Also, one or two elements selected from bromine and beryllium can be used.
添加元素にマグネシウムを選んだとき、添加元素源はマグネシウム源と呼ぶことができる。当該マグネシウム源としては、フッ化マグネシウム、酸化マグネシウム、水酸化マグネシウム、又は炭酸マグネシウム等を用いることができる。また上述したマグネシウム源を複数用いてもよい。 When magnesium is selected as the additive element, the source of the additive element can be called a magnesium source. The magnesium source can be magnesium fluoride, magnesium oxide, magnesium hydroxide, magnesium carbonate, or the like. In addition, multiple magnesium sources described above may be used.
添加元素にフッ素を選んだとき、添加元素源はフッ素源と呼ぶことができる。当該フッ素源としては、例えばフッ化リチウム（ＬｉＦ）、フッ化マグネシウム（ＭｇＦ２）、フッ化アルミニウム（ＡｌＦ３）、フッ化チタン（ＴｉＦ４）、フッ化コバルト（ＣｏＦ２、ＣｏＦ３）、フッ化ニッケル（ＮｉＦ２）、フッ化ジルコニウム（ＺｒＦ４）、フッ化バナジウム（ＶＦ５）、フッ化マンガン、フッ化鉄、フッ化クロム、フッ化ニオブ、フッ化亜鉛（ＺｎＦ２）、フッ化カルシウム（ＣａＦ２）、フッ化ナトリウム（ＮａＦ）、フッ化カリウム（ＫＦ）、フッ化バリウム（ＢａＦ２）、フッ化セリウム（ＣｅＦ３、ＣｅＦ４）、フッ化ランタン（ＬａＦ３）、又は六フッ化アルミニウムナトリウム（Ｎａ３ＡｌＦ６）等を用いることができる。中でも、フッ化リチウムは融点が８４８℃と比較的低く、後述する加熱工程で溶融しやすいため好ましい。 When fluorine is selected as the dopant element, the dopant element source can be referred to as a fluorine source. Examples of the fluorine source that can be used include lithium fluoride (LiF), magnesium fluoride ( MgF2 ), aluminum fluoride ( AlF3 ), titanium fluoride ( TiF4 ), cobalt fluoride ( CoF2 , CoF3 ), nickel fluoride ( NiF2 ), zirconium fluoride ( ZrF4 ), vanadium fluoride ( VF5 ), manganese fluoride, iron fluoride, chromium fluoride, niobium fluoride, zinc fluoride ( ZnF2 ), calcium fluoride ( CaF2 ), sodium fluoride (NaF), potassium fluoride (KF), barium fluoride ( BaF2 ), cerium fluoride ( CeF3 , CeF4 ), lanthanum fluoride ( LaF3 ), and sodium aluminum hexafluoride ( Na3AlF6 ). Among these, lithium fluoride is preferred because it has a relatively low melting point of 848° C. and is easily melted in the heating step described below.
フッ化マグネシウムは、フッ素源としてもマグネシウム源としても用いることができる。またフッ化リチウムは、フッ素源としてもリチウム源としても用いることができる。ステップＳ２１に用いられるその他のリチウム源としては、炭酸リチウムがある。 Magnesium fluoride can be used as both a fluorine source and a magnesium source. Lithium fluoride can be used as both a fluorine source and a lithium source. Another lithium source that can be used in step S21 is lithium carbonate.
またフッ素源は気体でもよく、フッ素（Ｆ２）、フッ化炭素、フッ化硫黄、又はフッ化酸素（ＯＦ２、Ｏ２Ｆ２、Ｏ３Ｆ２、Ｏ４Ｆ２、Ｏ５Ｆ２、Ｏ６Ｆ２、Ｏ２Ｆ）等を用い、後述する加熱工程において雰囲気中に混合させてもよい。また上述したフッ素源を複数用いてもよい。 The fluorine source may be a gas, such as fluorine ( F2 ), carbon fluoride, sulfur fluoride, or oxygen fluoride ( OF2 , O2F2 , O3F2 , O4F2 , O5F2 , O6F2 , O2F ) , which may be mixed into the atmosphere in the heating step described below. A plurality of the above-mentioned fluorine sources may be used.
本実施の形態では、フッ素源としてフッ化リチウム（ＬｉＦ）を準備し、フッ素源及びマグネシウム源としてフッ化マグネシウム（ＭｇＦ２）を準備する。フッ化リチウムとフッ化マグネシウムは、ＬｉＦ：ＭｇＦ２＝６５：３５（ｍｏｌ比）程度で混合すると融点を下げる効果が最も高くなる。一方、フッ化リチウムが多くなると、リチウムが過剰になりすぎサイクル特性が悪化する懸念がある。そのため、フッ化リチウムとフッ化マグネシウムのｍｏｌ比は、ＬｉＦ：ＭｇＦ２＝ｘ：１（０≦ｘ≦１．９）であることが好ましく、ＬｉＦ：ＭｇＦ２＝ｘ：１（０．１≦ｘ≦０．５）がより好ましく、ＬｉＦ：ＭｇＦ２＝ｘ：１（ｘ＝０．３３近傍）がさらに好ましい。なお本明細書等において近傍とは、その値の０．９倍より大きく１．１倍より小さい値とする。 In this embodiment, lithium fluoride (LiF) is prepared as the fluorine source, and magnesium fluoride (MgF 2 ) is prepared as the fluorine source and magnesium source. When lithium fluoride and magnesium fluoride are mixed at about LiF:MgF 2 = 65:35 (molar ratio), the effect of lowering the melting point is maximized. On the other hand, if the amount of lithium fluoride increases, there is a concern that the lithium becomes excessive and the cycle characteristics deteriorate. Therefore, the molar ratio of lithium fluoride and magnesium fluoride is preferably LiF:MgF 2 = x:1 (0≦x≦1.9), more preferably LiF:MgF 2 = x:1 (0.1≦x≦0.5), and even more preferably LiF:MgF 2 = x:1 (near x = 0.33). In this specification, etc., "near" refers to a value that is greater than 0.9 times and less than 1.1 times the value.
＜ステップＳ２２＞
次に、図１７Ｂに示すステップＳ２２では、マグネシウム源及びフッ素源を粉砕及び混合する。本工程は、ステップＳ１２で説明した粉砕及び混合の条件から選択して実施することができる。 <Step S22>
17B, the magnesium source and the fluorine source are pulverized and mixed. This step can be performed under the pulverization and mixing conditions selected from those described in step S12.
＜ステップＳ２３＞
次に、図１７Ｂに示すステップＳ２３では、上記で粉砕、混合した材料を回収して、添加元素Ａ源（Ａ源）を得ることができる。なお、ステップＳ２３に示す添加元素Ａ源は、複数の出発材料を有するものであり、混合物と呼ぶことができる。 <Step S23>
17B, the material crushed and mixed as described above is collected to obtain a source of additive element A (source A). Note that the source of additive element A shown in step S23 has a plurality of starting materials and can be called a mixture.
上記混合物の粒径は、メディアン径（Ｄ５０）が６００ｎｍ以上１０μｍ以下であることが好ましく、１μｍ以上５μｍ以下であることがより好ましい。添加元素源として、一種の材料を用いた場合においても、メディアン径（Ｄ５０）が６００ｎｍ以上１０μｍ以下であることが好ましく、１μｍ以上５μｍ以下であることがより好ましい。 The particle size of the mixture is preferably a median diameter (D50) of 600 nm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less. Even when a single material is used as the source of the additive element, the median diameter (D50) is preferably 600 nm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less.
このような微粉化された混合物（添加元素が一種の場合も含む）であると、後の工程でコバルト酸リチウムと混合したときに、コバルト酸リチウムの粒子の表面に混合物を均一に付着させやすい。コバルト酸リチウムの粒子の表面に混合物が均一に付着していると、加熱後に複合酸化物の表層部に均一に添加元素を分布又は拡散させやすいため好ましい。 Such a finely powdered mixture (including cases where only one additive element is included) makes it easier to uniformly attach the mixture to the surface of the lithium cobalt oxide particles when it is mixed with lithium cobalt oxide in a later process. If the mixture is uniformly attached to the surface of the lithium cobalt oxide particles, it is preferable because it makes it easier to uniformly distribute or diffuse the additive element in the surface layer of the composite oxide after heating.
＜ステップＳ２１＞
図１７Ｂとは異なる工程について、図１７Ｃを用いて説明する。図１７Ｃに示すステップＳ２１では、コバルト酸リチウムに添加する添加元素源を４種用意する。すなわち図１７Ｃは、図１７Ｂとは添加元素源の種類が異なる。添加元素源と合わせて、リチウム源を準備してもよい。 <Step S21>
A process different from that shown in FIG. 17B will be described with reference to FIG. 17C. In step S21 shown in FIG. 17C, four types of additive element sources to be added to lithium cobalt oxide are prepared. That is, the types of additive element sources shown in FIG. 17C are different from those shown in FIG. 17B. A lithium source may be prepared together with the additive element sources.
４種の添加元素源として、マグネシウム源（Ｍｇ源）、フッ素源（Ｆ源）、ニッケル源（Ｎｉ源）、及びアルミニウム源（Ａｌ源）を準備する。なお、マグネシウム源及びフッ素源は図１７Ｂで説明した化合物等から選択することができる。ニッケル源としては、酸化ニッケル、水酸化ニッケル等を用いることができる。アルミニウム源としては、酸化アルミニウム、水酸化アルミニウム、等を用いることができる。 As sources of the four types of additive elements, a magnesium source (Mg source), a fluorine source (F source), a nickel source (Ni source), and an aluminum source (Al source) are prepared. The magnesium source and the fluorine source can be selected from the compounds described in FIG. 17B. Nickel oxide, nickel hydroxide, etc. can be used as the nickel source. Aluminum oxide, aluminum hydroxide, etc. can be used as the aluminum source.
＜ステップＳ２２及びステップＳ２３＞
図１７Ｃに示すステップＳ２２及びステップＳ２３は、図１７Ｂで説明したステップと同様である。 <Steps S22 and S23>
Steps S22 and S23 shown in FIG. 17C are similar to the steps described in FIG. 17B.
＜ステップＳ１０１＞
次に、図１７Ａに示すステップＳ１０１では、コバルト酸リチウムと、添加元素Ａ源（Ａ源）とを混合する。コバルト酸リチウム中のコバルトの原子数Ｃｏと、添加元素Ａ源が有するマグネシウムの原子数Ｍｇとの比は、Ｃｏ：Ｍｇ＝１００：ｙ（０．１≦ｙ≦６）であることが好ましく、Ｃｏ：Ｍｇ＝１００：ｙ（０．３≦ｙ≦３）であることがより好ましい。 <Step S101>
17A, lithium cobalt oxide is mixed with a source of additive element A. The ratio of the number of cobalt atoms Co in the lithium cobalt oxide to the number of magnesium atoms Mg in the source of additive element A is preferably Co:Mg=100:y (0.1≦y≦6), and more preferably Co:Mg=100:y (0.3≦y≦3).
ステップＳ１０１の混合は、コバルト酸リチウムの粒子の形状を破壊させないためにステップＳ１２の混合よりも穏やかな条件とすることが好ましい。例えば、ステップＳ１２の混合よりも回転数が少ない、又は時間が短い条件とすることが好ましい。また湿式よりも乾式の方が穏やかな条件であると言える。混合には例えばボールミル、ビーズミル等を用いることができる。ボールミルを用いる場合は、例えばメディアとして酸化ジルコニウムボールを用いることが好ましい。 The mixing conditions in step S101 are preferably milder than those in step S12 in order not to destroy the shape of the lithium cobalt oxide particles. For example, the mixing conditions are preferably lower in rotation speed or shorter in time than those in step S12. It can also be said that the dry method has milder conditions than the wet method. For example, a ball mill, a bead mill, etc. can be used for mixing. When using a ball mill, it is preferable to use zirconium oxide balls as the media.
本実施の形態では、直径１ｍｍの酸化ジルコニウムボールを用いたボールミルで、１５０ｒｐｍ、１時間、乾式で混合することとする。また当該混合は、露点が−１００℃以上−１０℃以下のドライルームで行うこととする。 In this embodiment, the mixture is mixed dry in a ball mill using zirconium oxide balls with a diameter of 1 mm at 150 rpm for 1 hour. The mixture is performed in a dry room with a dew point of -100°C or higher and -10°C or lower.
＜ステップＳ１０２＞
次に、図１７ＡのステップＳ１０２において、上記で混合した材料を回収し、混合物９０３を得る。回収の際、必要に応じて解砕した後にふるいを実施してもよい。 <Step S102>
17A, the mixed material is collected to obtain a mixture 903. When collecting the material, it may be crushed and then sieved, if necessary.
なお図１７Ａ乃至図１７Ｃでは、初期加熱を経た後に添加元素を加える作製方法について説明しているが、本発明は上記方法に限定されない。添加元素は他のタイミングで加えてもよいし、複数回にわたって加えてもよい。添加元素によってタイミングを変えてもよい。 Note that although Figures 17A to 17C illustrate a fabrication method in which an additive element is added after initial heating, the present invention is not limited to the above method. The additive element may be added at a different timing, or may be added multiple times. The timing may be changed depending on the additive element.
例えば図１８Ａ乃至図１８Ｃに示すように、ステップＳ１１の段階、つまり複合酸化物の出発材料の段階で添加元素を、リチウム源及びコバルト源へ添加してもよい。図１８Ａでは、マグネシウム源を、リチウム源及びコバルト源へ添加するフローを示す。図１８Ｂでは、マグネシウム源及びアルミニウム源を、リチウム源及びコバルト源へ添加するフローを示す。図１８Ｃでは、マグネシウム源及びニッケル源を、リチウム源及びコバルト源へ添加するフローを示す。図１８Ａ乃至図１８Ｃに示した添加元素源は例示である。 For example, as shown in Figures 18A to 18C, the additive elements may be added to the lithium source and the cobalt source in step S11, i.e., at the stage of the starting material for the composite oxide. Figure 18A shows a flow of adding a magnesium source to a lithium source and a cobalt source. Figure 18B shows a flow of adding a magnesium source and an aluminum source to a lithium source and a cobalt source. Figure 18C shows a flow of adding a magnesium source and a nickel source to a lithium source and a cobalt source. The additive element sources shown in Figures 18A to 18C are examples.
その後ステップＳ１２へ続き、ステップＳ１３を経て、ステップＳ１４で添加元素を有するコバルト酸リチウムを得ることができる。添加元素を添加するタイミングに従って、添加元素の分布を制御することも可能である。図１８Ａ乃至図１８Ｃのように添加した添加元素は、正極活物質１００の内部に位置することが期待される。また図１８Ａ乃至図１８Ｃに示すフローの場合、上述したステップＳ１１乃至ステップＳ１４の工程と、ステップＳ２１乃至ステップＳ２３の工程を分けなくともよいため、簡便で生産性が高い方法であるといえる。勿論、図１８Ａ乃至図１８Ｃに示すフローであっても、ステップＳ２０で新たな添加元素を添加してもよい。 Then, the process proceeds to step S12, and then to step S13, and in step S14, lithium cobalt oxide having the additive element can be obtained. It is also possible to control the distribution of the additive element according to the timing of adding the additive element. The additive element added as shown in Figures 18A to 18C is expected to be located inside the positive electrode active material 100. In addition, in the case of the flow shown in Figures 18A to 18C, the above-mentioned steps S11 to S14 do not need to be separated from the steps S21 to S23, so it can be said to be a simple and highly productive method. Of course, even in the flow shown in Figures 18A to 18C, a new additive element may be added in step S20.
また、あらかじめ添加元素の一部を有するコバルト酸リチウムを用いてもよい。例えばマグネシウム及びフッ素が添加されたコバルト酸リチウムを用いれば、ステップＳ１１乃至ステップＳ１４、及びステップＳ２０の一部の工程を省略することができる。簡便で生産性が高い方法であるといえる。 Alternatively, lithium cobalt oxide that already contains some of the added elements may be used. For example, if lithium cobalt oxide to which magnesium and fluorine have been added is used, steps S11 to S14 and some of the steps in step S20 can be omitted. This is a simple and highly productive method.
また、あらかじめマグネシウム及びフッ素が添加されたコバルト酸リチウムに対して、ステップＳ１５の加熱を行った後、ステップＳ２０のようにマグネシウム源及びフッ素源、又はマグネシウム源、フッ素源、ニッケル源、及びアルミニウム源を添加してもよい。 Also, after heating in step S15 to lithium cobalt oxide to which magnesium and fluorine have been added in advance, a magnesium source and a fluorine source, or a magnesium source, a fluorine source, a nickel source, and an aluminum source may be added as in step S20.
＜ステップＳ１０３＞
次に、図１７Ａに示すステップＳ１０３では、混合物９０３を加熱する。当該加熱は、ステップＳ１３で説明した加熱条件から選択して実施することができる。加熱時間は２時間以上が好ましい。このとき、加熱雰囲気の酸素分圧を高めるため、炉内は大気圧を超えた圧力であってもよい。加熱雰囲気の酸素分圧が不足すると、コバルト等が還元され、コバルト酸リチウム等が層状岩塩型の結晶構造を保てなくなる恐れがあるためである。 <Step S103>
Next, in step S103 shown in Fig. 17A, the mixture 903 is heated. The heating can be performed under a heating condition selected from those described in step S13. The heating time is preferably 2 hours or more. At this time, the pressure inside the furnace may be higher than atmospheric pressure in order to increase the oxygen partial pressure of the heating atmosphere. This is because if the oxygen partial pressure of the heating atmosphere is insufficient, cobalt, etc. will be reduced, and lithium cobalt oxide, etc. may not be able to maintain the layered rock salt type crystal structure.
ここで加熱温度について補足する。ステップＳ１０３の加熱温度の下限は、コバルト酸リチウムと添加元素源との反応が進む温度以上である必要がある。反応が進む温度とは、コバルト酸リチウムと添加元素源の有する元素との相互拡散が起きる温度であればよく、これらの材料の溶融温度よりも低くてもよい。酸化物を例にして説明するが、溶融温度Ｔｍの０．７５７倍（タンマン温度Ｔｄ）から固相拡散が起こることがわかっている。そのため、ステップＳ１０３における加熱温度としては、６５０℃以上であればよい。 Here, a supplementary note on the heating temperature is provided. The lower limit of the heating temperature in step S103 must be equal to or higher than the temperature at which the reaction between the lithium cobalt oxide and the additive element source proceeds. The temperature at which the reaction proceeds may be any temperature at which mutual diffusion between the lithium cobalt oxide and the elements contained in the additive element source occurs, and may be lower than the melting temperature of these materials. An oxide is used as an example for explanation, and it is known that solid-phase diffusion occurs at a temperature 0.757 times the melting temperature Tm (Tammann temperature Td ). Therefore, the heating temperature in step S103 may be 650°C or higher.
勿論、混合物９０３が有する材料から選ばれた一又は二以上が溶融する温度以上であると、より反応が進みやすい。例えば、添加元素源として、ＬｉＦ及びＭｇＦ２を有する場合、ＬｉＦとＭｇＦ２の共融点は７４２℃付近であるため、ステップＳ１０３の加熱温度の下限は７４２℃以上とすると好ましい。 Of course, the reaction proceeds more easily if the temperature is equal to or higher than the melting temperature of one or more of the materials contained in the mixture 903. For example, when LiF and MgF2 are contained as the additive element source, the eutectic point of LiF and MgF2 is around 742°C, so that the lower limit of the heating temperature in step S103 is preferably 742°C or higher.
また、ＬｉＣｏＯ２：ＬｉＦ：ＭｇＦ２＝１００：０．３３：１（モル比）となるように混合して得られた混合物９０３は、ＤＳＣ測定において８３０℃付近に吸熱ピークが観測される。よって、加熱温度の下限は８３０℃以上がより好ましい。 Furthermore, in the mixture 903 obtained by mixing so that LiCoO 2 :LiF:MgF 2 =100:0.33:1 (molar ratio), an endothermic peak is observed in the vicinity of 830° C. in the DSC measurement. Therefore, the lower limit of the heating temperature is more preferably 830° C. or higher.
加熱温度は高い方が反応が進みやすく、加熱時間が短く済み、生産性が高く好ましい。 The higher the heating temperature, the easier the reaction will proceed, the shorter the heating time will be, and the higher the productivity will be, which is preferable.
加熱温度の上限は、コバルト酸リチウムの融点（１１３０℃）未満とする。融点の近傍の温度では、微量ではあるがコバルト酸リチウムの分解が懸念される。そのため、加熱温度の上限は、１０００℃以下であるとより好ましく、９５０℃以下であるとさらに好ましく、９００℃以下であるとさらに好ましい。 The upper limit of the heating temperature is below the melting point of lithium cobalt oxide (1130°C). At temperatures close to the melting point, there is a concern that lithium cobalt oxide may decompose, albeit only slightly. Therefore, the upper limit of the heating temperature is preferably 1000°C or lower, more preferably 950°C or lower, and even more preferably 900°C or lower.
これらを踏まえると、ステップＳ１０３における加熱温度としては、６５０℃以上１１３０℃以下が好ましく、６５０℃以上１０００℃以下がより好ましく、６５０℃以上９５０℃以下がさらに好ましく、６５０℃以上９００℃以下がさらに好ましい。また、７４２℃以上１１３０℃以下が好ましく、７４２℃以上１０００℃以下がより好ましく、７４２℃以上９５０℃以下がさらに好ましく、７４２℃以上９００℃以下がさらに好ましい。また、８３０℃以上１１３０℃以下が好ましく、８３０℃以上１０００℃以下がより好ましく、８３０℃以上９５０℃以下がさらに好ましく、８３０℃以上９００℃以下がさらに好ましい。なおステップＳ１０３における加熱温度は、ステップＳ１３の加熱温度よりも低いとよい。 In light of these, the heating temperature in step S103 is preferably 650°C to 1130°C, more preferably 650°C to 1000°C, even more preferably 650°C to 950°C, and even more preferably 650°C to 900°C. Also, 742°C to 1130°C is preferred, more preferably 742°C to 1000°C, even more preferably 742°C to 950°C, and even more preferably 742°C to 900°C. Also, 830°C to 1130°C is preferred, more preferably 830°C to 1000°C, even more preferably 830°C to 950°C, and even more preferably 830°C to 900°C. The heating temperature in step S103 is preferably lower than the heating temperature in step S13.
上記ステップＳ１０３の加熱後の冷却は自然放冷でよいが、規定温度から室温までの降温時間が１０時間以上５０時間以下に収まると好ましく、例えば降温速度（以降、冷却速度とも呼ぶ）は８０℃／時間以上２５０℃／時間以下がよく、１８０℃／時間以上２１０℃／時間以下がより好ましい。本ステップＳ１０３の冷却速度は、ステップＳ１３と比べて速いと好ましい。冷却速度の速いことを急冷と呼ぶ。上記溶融した後に急冷を実施すると、シェルを適切に作製することができる。具体的には、幅狭なシェルを作製することが可能になる。なお降温完了時の温度は必ずしも室温を要せず、次のステップが許容する温度まで冷却されればよい。 The cooling after heating in step S103 may be allowed to cool naturally, but it is preferable that the time required for the temperature to drop from the specified temperature to room temperature is within 10 to 50 hours. For example, the temperature drop rate (hereinafter also referred to as the cooling rate) is preferably 80°C/hour to 250°C/hour, more preferably 180°C/hour to 210°C/hour. The cooling rate in step S103 is preferably faster than that in step S13. A fast cooling rate is called rapid cooling. By performing rapid cooling after the melting, a shell can be appropriately produced. Specifically, it becomes possible to produce a narrow shell. The temperature at the end of the temperature drop does not necessarily have to be room temperature, and it is sufficient to cool to a temperature that is acceptable for the next step.
さらに混合物９０３を加熱する際、フッ素源等に起因するフッ素又はフッ素化合物の分圧を適切な範囲に制御することが好ましい。本ステップに用いるるつぼに蓋を配して加熱することで、分圧を制御することも可能である。なお上述したが蓋により、材料の揮発又は昇華を防ぐことができる。そのため、本ステップの昇温時から降温時において、材料の揮発又は昇華を防ぐことができればよく、必ずしも蓋によりるつぼを密閉しなくともよい。例えば、るつぼを置く反応室内に酸素を充填することで、るつぼを密閉しないで本ステップを実施することも可能になる。フッ素又はフッ素化合物を適切に有する正極活物質は、内部短絡した場合であっても発熱及び発煙を抑制することができるため好ましい。 Furthermore, when heating the mixture 903, it is preferable to control the partial pressure of fluorine or fluorine compounds due to the fluorine source, etc., within an appropriate range. It is also possible to control the partial pressure by placing a lid on the crucible used in this step and heating it. As described above, the lid can prevent the material from volatilizing or sublimating. Therefore, it is not necessary to seal the crucible with a lid as long as it is possible to prevent the material from volatilizing or sublimating during the temperature increase and decrease in this step. For example, by filling the reaction chamber in which the crucible is placed with oxygen, it is also possible to carry out this step without sealing the crucible. A positive electrode active material having an appropriate amount of fluorine or fluorine compounds is preferable because it can suppress heat generation and smoke generation even in the event of an internal short circuit.
本実施の形態で説明する作製方法では、一部の材料、例えばフッ素源であるＬｉＦが融剤として機能する場合がある。この機能により加熱温度をコバルト酸リチウムの融点未満、例えば７４２℃以上９５０℃以下にまで低温化でき、表層部にマグネシウムをはじめとする添加元素を分布させ、良好な特性の正極活物質を作製できる。 In the manufacturing method described in this embodiment, some materials, for example LiF, which is a fluorine source, may function as a flux. This function allows the heating temperature to be lowered to below the melting point of lithium cobalt oxide, for example to 742°C or higher and 950°C or lower, and additive elements such as magnesium can be distributed in the surface layer to produce a positive electrode active material with good characteristics.
しかし、ＬｉＦは酸素よりも気体状態での比重が軽いため、加熱によりＬｉＦが揮発する可能性があり、揮発すると混合物９０３中のＬｉＦが減少してしまう。すると融剤としての機能が弱くなってしまう。よって、ＬｉＦの揮発を抑制しつつ、加熱する必要がある。なお、フッ素源等としてＬｉＦを用いなかったとしても、ＬｉＣｏＯ２表面のＬｉとフッ素源のＦが反応して、ＬｉＦが生じ、揮発する可能性もある。そのため、ＬｉＦより融点が高いフッ素化合物を用いたとしても、同じように揮発の抑制が必要である。 However, since LiF has a lower specific gravity in a gaseous state than oxygen, LiF may volatilize when heated, and the amount of LiF in the mixture 903 will decrease if LiF volatilizes. This weakens the function as a flux. Therefore, it is necessary to heat while suppressing the volatilization of LiF. Even if LiF is not used as the fluorine source, etc., Li on the LiCoO2 surface may react with F of the fluorine source to generate LiF, which may volatilize. Therefore, even if a fluorine compound with a melting point higher than LiF is used, it is necessary to suppress the volatilization in the same way.
そこで、ＬｉＦを含む雰囲気で混合物９０３を加熱すること、すなわち、加熱炉内のＬｉＦの分圧が高い状態で混合物９０３を加熱することが好ましい。このような加熱により、混合物９０３中のＬｉＦの揮発を抑制することができる。ＬｉＦの揮発を抑制するためにも、るつぼに蓋を配するとよい。 Therefore, it is preferable to heat the mixture 903 in an atmosphere containing LiF, that is, to heat the mixture 903 in a state where the partial pressure of LiF in the heating furnace is high. By heating in this manner, it is possible to suppress the volatilization of LiF in the mixture 903. It is also preferable to place a lid on the crucible in order to suppress the volatilization of LiF.
本工程の加熱は、混合物９０３の粒子同士が固着しないように加熱すると好ましい。加熱中に混合物９０３の粒子同士が固着すると、雰囲気中の酸素との接触面積が減る、及び添加元素（例えばフッ素）が拡散する経路を阻害することにより、表層部への添加元素（例えばマグネシウム及びフッ素）の分布が悪化する可能性がある。雰囲気中の酸素との反応を促進させるためにも、蓋によりるつぼを密閉しなくともよい。 The heating in this process is preferably performed so that the particles of mixture 903 do not stick to each other. If the particles of mixture 903 stick to each other during heating, the contact area with oxygen in the atmosphere decreases, and the route along which the added element (e.g., fluorine) diffuses is blocked, which may result in poor distribution of the added element (e.g., magnesium and fluorine) in the surface layer. In order to promote the reaction with oxygen in the atmosphere, the crucible does not need to be sealed with a lid.
また、添加元素（例えばフッ素）が表層部に均一に分布すると、なめらかで凹凸が少ない正極活物質を得られると考えられている。そのため本工程により、ステップＳ１５の加熱を経た後の表面がなめらかな状態を維持する、又は、より一層なめらかにするためには、混合物９０３の粒子同士が固着しない方がよい。 In addition, it is believed that if the additive element (e.g., fluorine) is uniformly distributed in the surface layer, a smooth positive electrode active material with few irregularities can be obtained. Therefore, in order to maintain the smooth state of the surface after the heating in step S15 in this process, or to make it even smoother, it is better for the particles of mixture 903 not to stick together.
また、ロータリーキルンによって加熱する場合は、キルン内の酸素を含む雰囲気の流量を制御して加熱することが好ましい。例えば酸素を含む雰囲気の流量を少なくする、最初に雰囲気をパージしキルン内に酸素雰囲気を導入した後は雰囲気のフローはしない、等が好ましい。酸素をフローするとフッ素源が蒸散する可能性があり、表面のなめらかさを維持するためには好ましくない。 When heating in a rotary kiln, it is preferable to control the flow rate of the oxygen-containing atmosphere in the kiln. For example, it is preferable to reduce the flow rate of the oxygen-containing atmosphere, or to first purge the atmosphere and not flow the atmosphere after introducing the oxygen atmosphere into the kiln. Flowing oxygen can cause the fluorine source to evaporate, which is not preferable in terms of maintaining the smoothness of the surface.
ローラーハースキルンによって加熱する場合は、例えば混合物９０３の入った容器に蓋を配することで、ＬｉＦを含む雰囲気で混合物９０３を加熱することができる。るつぼに配する蓋と同様である。 When heating using a roller hearth kiln, the mixture 903 can be heated in an atmosphere containing LiF by, for example, placing a lid on the container containing the mixture 903. This is similar to the lid placed on a crucible.
加熱時間について補足する。加熱時間は、加熱温度、ステップＳ１４で得られるコバルト酸リチウムの大きさ、及び組成等の条件により変化する。コバルト酸リチウムが小さい場合は、大きい場合よりも低い温度又は短い時間がより好ましい場合がある。 A note on the heating time: The heating time varies depending on conditions such as the heating temperature, the size of the lithium cobalt oxide obtained in step S14, and the composition. When the lithium cobalt oxide is small, a lower temperature or a shorter heating time may be more preferable than when the lithium cobalt oxide is large.
図１７ＡのステップＳ１４で得られるコバルト酸リチウムのメディアン径（Ｄ５０）が１２μｍ程度の場合、加熱温度は、例えば６５０℃以上９５０℃以下が好ましい。加熱時間は、例えば３時間以上６０時間以下が好ましく、１０時間以上３０時間以下がより好ましく、２０時間程度がさらに好ましい。なお、加熱後の降温時間は、例えば１０時間以上５０時間以下とすることが好ましい。 When the median diameter (D50) of the lithium cobalt oxide obtained in step S14 in FIG. 17A is about 12 μm, the heating temperature is preferably, for example, 650° C. or more and 950° C. or less. The heating time is preferably, for example, 3 hours or more and 60 hours or less, more preferably 10 hours or more and 30 hours or less, and even more preferably about 20 hours. The cooling time after heating is preferably, for example, 10 hours or more and 50 hours or less.
一方、ステップＳ１４で得られるコバルト酸リチウムのメディアン径（Ｄ５０）が５μｍ程度の場合、加熱温度は、例えば６５０℃以上９５０℃以下が好ましい。加熱時間は、例えば１時間以上１０時間以下が好ましく、５時間程度がより好ましい。なお、加熱後の降温時間は、例えば１０時間以上５０時間以下とすることが好ましい。 On the other hand, when the median diameter (D50) of the lithium cobalt oxide obtained in step S14 is about 5 μm, the heating temperature is preferably, for example, 650° C. or more and 950° C. or less. The heating time is preferably, for example, 1 hour or more and 10 hours or less, and more preferably about 5 hours. The cooling time after heating is preferably, for example, 10 hours or more and 50 hours or less.
＜ステップＳ１０４＞
次に、図１７Ａに示すステップＳ１０４では、加熱した材料を回収し、必要に応じて解砕して、正極活物質１００を得る。このとき、回収された粒子をさらに、ふるいにかけてもよい。以上の工程により、本発明の一形態の正極活物質１００を作製することができる。本発明の一形態の正極活物質は表面がなめらかである。 <Step S104>
17A, the heated material is collected and crushed as necessary to obtain the positive electrode active material 100. At this time, the collected particles may be sieved. Through the above steps, the positive electrode active material 100 according to one embodiment of the present invention can be produced. The positive electrode active material according to one embodiment of the present invention has a smooth surface.
［正極活物質の製造方法５］
次に、本発明を実施する一形態であって、正極活物質の作製方法４とは異なる正極活物質の作製方法５について、図１９乃至図２０Ｃを用いて説明する。正極活物質の作製方法５は、主に添加元素を加える回数及び混合方法が作製方法４とは異なる。その他の記載は作製方法４の記載を参照することができる。 [Method of manufacturing positive electrode active material 5]
19 to 20C , a description will be given of a method 5 for producing a positive electrode active material, which is an embodiment of the present invention and is different from the method 4 for producing a positive electrode active material. The method 5 for producing a positive electrode active material differs from the method 4 for producing a positive electrode active material mainly in the number of times that the additive elements are added and the mixing method. For other descriptions, the description of the method 4 can be referred to.
図１９おいて、図１７Ａと同様にステップＳ１１乃至Ｓ１５までを行い、初期加熱を経たコバルト酸リチウムを準備する。 In FIG. 19, steps S11 to S15 are performed in the same manner as in FIG. 17A to prepare lithium cobalt oxide that has undergone initial heating.
＜ステップＳ２０ａ＞
次にステップＳ２０ａに示すように、初期加熱を経たコバルト酸リチウムに加える添加元素Ａ１を用意することが好ましい。 <Step S20a>
Next, as shown in step S20a, it is preferable to prepare an additive element A1 to be added to the lithium cobalt oxide that has been subjected to the initial heating.
＜ステップＳ２１＞
図２０Ａに示すステップＳ２１では、第１の添加元素源を準備する。第１の添加元素源としては、図１７Ｂに示すステップＳ２１で説明した添加元素Ａの中から選択して用いることができる。例えば、添加元素Ａ１としては、マグネシウム、フッ素、及びカルシウムの中から選ばれるいずれか一又は複数を好適に用いることができる。図２０Ａでは第１の添加元素源として、マグネシウム源（Ｍｇ源）、及びフッ素源（Ｆ源）を用いる場合を例示する。 <Step S21>
In step S21 shown in Fig. 20A, a first additive element source is prepared. The first additive element source can be selected from the additive elements A described in step S21 shown in Fig. 17B. For example, the additive element A1 can be one or more selected from magnesium, fluorine, and calcium. Fig. 20A illustrates an example in which a magnesium source (Mg source) and a fluorine source (F source) are used as the first additive element source.
図２０Ａに示すステップＳ２１乃至ステップＳ２３については、図１７Ｂに示すステップＳ２１乃至ステップＳ２３と同様の条件で行うことができる。その結果、ステップＳ２３で添加元素源（Ａ１源）を得ることができる。 Steps S21 to S23 shown in FIG. 20A can be performed under the same conditions as steps S21 to S23 shown in FIG. 17B. As a result, an additive element source (A1 source) can be obtained in step S23.
また、図１９に示すステップＳ１０１乃至ステップＳ１０３については、図１７Ａに示すステップＳ１０１乃至ステップＳ１０３と同様の工程にて行うことができる。 Furthermore, steps S101 to S103 shown in FIG. 19 can be performed in the same manner as steps S101 to S103 shown in FIG. 17A.
＜ステップＳ１０４ａ＞
次に、ステップＳ３３で加熱した材料を回収し、添加元素Ａ１を有するコバルト酸リチウムを作製する。ステップＳ１４の複合酸化物と区別するため、第２の複合酸化物とも呼ぶ。 <Step S104a>
Next, in step S33, the heated material is collected to produce lithium cobalt oxide containing the additive element A1. To distinguish this from the composite oxide in step S14, this is also called a second composite oxide.
＜ステップＳ１１０＞
図１９に示すステップＳ１１０では、添加元素Ａ２を用意する。図２０Ｂ及び図２０Ｃも参照しながら添加元素Ａ２を用意する手順を説明する。 <Step S110>
In step S110 shown in Fig. 19, the additive element A2 is prepared. The procedure for preparing the additive element A2 will be described with reference to Figs. 20B and 20C.
＜ステップＳ１１１＞
図２０Ｂに示すステップＳ１１１では、第２の添加元素源を準備する。第２の添加元素源としては、図１７Ｃに示すステップＳ２１で説明した添加元素Ａの中から選択して用いることができる。例えば、添加元素Ａ２としては、ニッケル、チタン、ホウ素、ジルコニウム、及びアルミニウムの中から選ばれるいずれか一又は複数を好適に用いることができる。図２０Ｂでは第２の添加元素源として、ニッケル源（Ｎｉ源）、及びアルミニウム源（Ａｌ源）を用いる場合を例示する。 <Step S111>
In step S111 shown in Fig. 20B, a second additive element source is prepared. The second additive element source can be selected from the additive elements A described in step S21 shown in Fig. 17C. For example, the additive element A2 can be one or more selected from nickel, titanium, boron, zirconium, and aluminum. Fig. 20B illustrates an example in which a nickel source (Ni source) and an aluminum source (Al source) are used as the second additive element source.
図２０Ｂに示すステップＳ１１１乃至ステップＳ１１３については、図１７Ｂに示すステップＳ２１乃至ステップＳ２３と同様の条件で行うことができる。その結果、ステップＳ１１３で添加元素源（Ａ２源）を得ることができる。 Steps S111 to S113 shown in FIG. 20B can be performed under the same conditions as steps S21 to S23 shown in FIG. 17B. As a result, an additive element source (A2 source) can be obtained in step S113.
また、図２０Ｃには、図２０Ｂを用いて説明したステップの変形例を示す。図２０Ｃに示すステップＳ１１１では、ニッケル源（Ｎｉ源）、及びアルミニウム源（Ａｌ源）を準備し、ステップＳ１１２ａでは、それぞれ独立に粉砕する。その結果、ステップＳ１１３では、複数の第２の添加元素源（Ａ２源）を準備することとなる。図２０Ｃのステップは、ステップＳ１１２ａにて、添加元素を独立に粉砕していることが図２０Ｂと異なる。 Furthermore, FIG. 20C shows a modified example of the steps described with reference to FIG. 20B. In step S111 shown in FIG. 20C, a nickel source (Ni source) and an aluminum source (Al source) are prepared, and in step S112a, they are each crushed independently. As a result, in step S113, multiple second additive element sources (A2 sources) are prepared. The steps in FIG. 20C differ from FIG. 20B in that the additive elements are crushed independently in step S112a.
＜ステップＳ１２１乃至ステップＳ１２４＞
次に、図１９に示すステップＳ１２１乃至ステップＳ１２４は、図１７Ａに示すステップＳ１０１乃至ステップＳ１０４と同様の条件にて行うことができる。加熱工程に関するステップＳ１２３の条件は、ステップＳ１０３より低い温度かつ短い時間でよい。以上の工程により、ステップＳ１２４では、本発明の一形態の正極活物質１００を作製することができる。本発明の一形態の正極活物質は表面がなめらかである。 <Steps S121 to S124>
Next, steps S121 to S124 shown in Fig. 19 can be performed under the same conditions as steps S101 to S104 shown in Fig. 17A. The conditions for step S123 relating to the heating step may be a lower temperature and a shorter time than those for step S103. Through the above steps, in step S124, the positive electrode active material 100 according to one embodiment of the present invention can be produced. The positive electrode active material according to one embodiment of the present invention has a smooth surface.
図１９乃至図２０Ｃに示すように、作製方法２では、コバルト酸リチウムへの添加元素を添加元素Ａ１と、添加元素Ａ２とに分けて導入する。分けて導入することにより、各添加元素の深さ方向の存在位置等を変えることができる。例えば、添加元素Ａ１を内部に比べて表層部で高い濃度となるように位置させ、添加元素Ａ２を表層部に比べて内部で高い濃度となるように位置させることも可能である。 As shown in Figures 19 to 20C, in manufacturing method 2, the additive element is introduced into lithium cobalt oxide in two parts, additive element A1 and additive element A2. By introducing them separately, the location of each additive element in the depth direction can be changed. For example, it is possible to position additive element A1 so that it has a higher concentration in the surface layer than in the interior, and to position additive element A2 so that it has a higher concentration in the interior than in the surface layer.
本実施の形態で示した初期加熱を経ると、表面がなめらかな正極活物質を得ることができる。 After the initial heating process described in this embodiment, a positive electrode active material with a smooth surface can be obtained.
本実施の形態で示した初期加熱は、コバルト酸リチウムに対して実施する。よって初期加熱は、コバルト酸リチウムを得るための加熱温度よりも低く、かつコバルト酸リチウムを得るための加熱時間よりも短い条件が好ましい。コバルト酸リチウムに添加元素を添加する工程は、初期加熱後が好ましい。当該添加工程は、２回以上に分けることが可能である。このような工程順に従うと、初期加熱で得られた表面のなめらかさが維持されるため好ましい。 The initial heating shown in this embodiment is performed on lithium cobalt oxide. Therefore, the initial heating is preferably performed under conditions that are lower than the heating temperature for obtaining lithium cobalt oxide and shorter than the heating time for obtaining lithium cobalt oxide. The step of adding an additive element to lithium cobalt oxide is preferably performed after the initial heating. This addition step can be divided into two or more steps. Following this order of steps is preferable because it maintains the smoothness of the surface obtained by the initial heating.
表面がなめらかな正極活物質１００は、そうでない正極活物質よりも加圧等による物理的な破壊に強い可能性がある。例えば、釘刺し試験のような加圧を伴う試験において正極活物質１００が破壊されにくく、結果として安全性が高まる可能性がある。 Positive electrode active material 100 with a smooth surface may be more resistant to physical destruction caused by pressure, etc., than positive electrode active material that does not have a smooth surface. For example, the positive electrode active material 100 is less likely to be destroyed in a test involving pressure, such as a nail penetration test, which may result in increased safety.
本実施の形態は、他の実施の形態と組み合わせて用いることができる。 This embodiment can be used in combination with other embodiments.
（実施の形態７）
本実施の形態では、上記実施の形態に適用できる電池セルとして全固体電池を説明する。本実施の形態で示す正極活物質の全固体電池は、断りのない限り、常温用バッテリ又は低温用バッテリに適用できる。 (Seventh embodiment)
In this embodiment, an all-solid-state battery will be described as a battery cell that can be applied to the above embodiment. The all-solid-state battery using the positive electrode active material described in this embodiment can be applied to a room temperature battery or a low temperature battery unless otherwise specified.
図２１Ａに示すように、本発明の一態様の電池セル４００は全固体電池であり、正極４１０、固体電解質層４２０及び負極４３０を有する。 As shown in FIG. 21A, the battery cell 400 of one embodiment of the present invention is an all-solid-state battery and has a positive electrode 410, a solid electrolyte layer 420, and a negative electrode 430.
正極４１０は正極集電体４１３及び正極活物質層４１４を有する。正極活物質層４１４は正極活物質４１１及び固体電解質４２１を有する。また正極活物質層４１４は、導電助剤及びバインダを有していてもよい。 The positive electrode 410 has a positive electrode current collector 413 and a positive electrode active material layer 414. The positive electrode active material layer 414 has a positive electrode active material 411 and a solid electrolyte 421. The positive electrode active material layer 414 may also have a conductive additive and a binder.
固体電解質層４２０は固体電解質４２１を有する。固体電解質層４２０は、正極４１０と負極４３０の間に位置し、正極活物質４１１及び負極活物質４３１のいずれも有さない領域である。 The solid electrolyte layer 420 has a solid electrolyte 421. The solid electrolyte layer 420 is located between the positive electrode 410 and the negative electrode 430, and is a region that has neither the positive electrode active material 411 nor the negative electrode active material 431.
負極４３０は負極集電体４３３及び負極活物質層４３４を有する。負極活物質層４３４は負極活物質４３１及び固体電解質４２１を有する。また負極活物質層４３４は、導電助剤及びバインダを有していてもよい。なお、負極活物質４３１として金属リチウムを用いる場合は粒子にする必要がないため、図２１Ｂのように、固体電解質４２１を有さない負極４３０とすることができる。負極４３０に金属リチウムを用いると、電池セル４００のエネルギー密度を向上させることができ好ましい。 The negative electrode 430 has a negative electrode current collector 433 and a negative electrode active material layer 434. The negative electrode active material layer 434 has a negative electrode active material 431 and a solid electrolyte 421. The negative electrode active material layer 434 may also have a conductive additive and a binder. When metallic lithium is used as the negative electrode active material 431, it is not necessary to make it into particles, so the negative electrode 430 can be made without a solid electrolyte 421, as shown in FIG. 21B. Using metallic lithium for the negative electrode 430 is preferable because it can improve the energy density of the battery cell 400.
固体電解質層４２０が有する固体電解質４２１としては、例えば硫化物系固体電解質、酸化物系固体電解質、ハロゲン化物系固体電解質等を用いることができる。 The solid electrolyte 421 in the solid electrolyte layer 420 may be, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or the like.
再掲するが、硫化物系固体電解質には、チオリシコン系（Ｌｉ１０ＧｅＰ２Ｓ１２、Ｌｉ３．２５Ｇｅ０．２５Ｐ０．７５Ｓ４等）、硫化物ガラス（７０Ｌｉ２Ｓ・３０Ｐ２Ｓ５３０Ｌｉ２Ｓ・２６Ｂ２Ｓ３・４４ＬｉＩ、６３Ｌｉ２Ｓ・３６ＳｉＳ２・１Ｌｉ３ＰＯ４、５７Ｌｉ２Ｓ・３８ＳｉＳ２・５Ｌｉ４ＳｉＯ４、５０Ｌｉ２Ｓ・５０ＧｅＳ２等）、硫化物結晶化ガラス（Ｌｉ７Ｐ３Ｓ１１、Ｌｉ３．２５Ｐ０．９５Ｓ４等）が含まれる。硫化物系固体電解質は、高い伝導度を有する材料がある、低い温度で合成可能、また比較的やわらかいため充放電を経ても導電経路が保たれやすい等の利点がある。 To repeat, sulfide-based solid electrolytes include thiolithium - based electrolytes ( Li10GeP2S12 , Li3.25Ge0.25P0.75S4 , etc. ) , sulfide glass ( 70Li2S.30P2S530Li2S.26B2S3.44LiI , 63Li2S.36SiS2.1Li3PO4 , 57Li2S.38SiS2.5Li4SiO4 , 50Li2S.50GeS2 , etc. ) , and sulfide crystallized glass (Li7P3S11 , Li3.25P0.95S4 , etc. ) . Sulfide-based solid electrolytes have the advantages of being highly conductive, being able to be synthesized at low temperatures, and being relatively soft, which makes it easier to maintain conductive paths even after charging and discharging.
再掲するが、酸化物系固体電解質には、ペロブスカイト型結晶構造を有する材料（Ｌａ２／３−ｘＬｉ３ｘＴｉＯ３等）、ＮＡＳＩＣＯＮ型結晶構造を有する材料（Ｌｉ１−ＹＡｌＹＴｉ２−Ｙ（ＰＯ４）３等）、ガーネット型結晶構造を有する材料（Ｌｉ７Ｌａ３Ｚｒ２Ｏ１２等）、ＬＩＳＩＣＯＮ型結晶構造を有する材料（Ｌｉ１４ＺｎＧｅ４Ｏ１６等）、ＬＬＺＯ（Ｌｉ７Ｌａ３Ｚｒ２Ｏ１２）、酸化物ガラス（Ｌｉ３ＰＯ４−Ｌｉ４ＳｉＯ４、５０Ｌｉ４ＳｉＯ４・５０Ｌｉ３ＢＯ３等）、酸化物結晶化ガラス（Ｌｉ１．０７Ａｌ０．６９Ｔｉ１．４６（ＰＯ４）３、Ｌｉ１．５Ａｌ０．５Ｇｅ１．５（ＰＯ４）３等）が含まれる。酸化物系固体電解質は、大気中で安定であるといった利点がある。 To repeat, oxide-based solid electrolytes include materials having a perovskite crystal structure ( La2/3- xLi3xTiO3 , etc.), materials having a NASICON crystal structure (Li1 - YAlYTi2 -Y ( PO4 ) 3 , etc.), materials having a garnet crystal structure ( Li7La3Zr2O12 , etc.), materials having a LISICON crystal structure ( Li14ZnGe4O16 , etc. ), LLZO ( Li7La3Zr2O12 ) , oxide glass ( Li3PO4 - Li4SiO4 , 50Li4SiO4.50Li3BO3 , etc. ) , oxide crystallized glass ( Li1.07Al0.69Ti1.46 ( PO 4 ) 3 , Li1.5Al0.5Ge1.5 ( PO4 ) 3 , etc. Oxide-based solid electrolytes have the advantage of being stable in the air .
再掲するが、ハロゲン化物系固体電解質には、ＬｉＡｌＣｌ４、Ｌｉ３ＩｎＢｒ６、ＬｉＦ、ＬｉＣｌ、ＬｉＢｒ、ＬｉＩ等が含まれる。また、これらハロゲン化物系固体電解質を、ポーラス酸化アルミニウム又はポーラスシリカの細孔に充填したコンポジット材料も固体電解質として用いることができる。 To repeat, halide-based solid electrolytes include LiAlCl 4 , Li 3 InBr 6 , LiF, LiCl, LiBr, LiI, etc. Also, composite materials in which these halide-based solid electrolytes are filled into the pores of porous aluminum oxide or porous silica can be used as solid electrolytes.
また、異なる固体電解質を混合して用いてもよい。 Different solid electrolytes may also be mixed and used.
再掲するが、ＮＡＳＩＣＯＮ型結晶構造を有するＬｉ１＋ｘＡｌｘＴｉ２−ｘ（ＰＯ４）３（０＜ｘ＜１）（以下、ＬＡＴＰ）は、アルミニウムとチタンという、本発明の一態様の電池セルに用いる正極活物質が有してもよい元素を含むため、サイクル特性の向上について相乗効果が期待でき好ましい。また、工程の削減による生産性の向上も期待できる。なお本明細書等において、ＮＡＳＩＣＯＮ型結晶構造とは、Ｍ２（ＸＯ４）３（Ｍ：遷移金属、Ｘ：Ｓ、Ｐ、Ａｓ、Ｍｏ、Ｗ等）で表される化合物であり、ＭＯ６八面体とＸＯ４四面体が頂点を共有して３次元的に配列した構造を有するものをいう。 Again, Li1 + xAlxTi2 -x ( PO4 ) 3 (0<x<1) (hereinafter, LATP) having a NASICON crystal structure contains aluminum and titanium, which are elements that may be contained in the positive electrode active material used in the battery cell of one embodiment of the present invention, and is therefore preferable because it is expected to have a synergistic effect in improving cycle characteristics. In addition, it is expected to improve productivity by reducing the number of steps. In this specification and the like, the NASICON crystal structure refers to a compound represented by M2 ( XO4 ) 3 (M: transition metal, X: S, P, As, Mo, W, etc.), which has a structure in which MO6 octahedrons and XO4 tetrahedrons are arranged three-dimensionally with vertices shared.
本実施の形態は、他の実施の形態と適宜組み合わせて用いることができる。 This embodiment can be used in appropriate combination with other embodiments.
（実施の形態８）
本実施の形態では、バッテリの他の構成例について図２２及び図２３を用いて説明する。本実施の形態で示すバッテリの他の構成例は、断りのない限り、第１のバッテリ１０１ａ又は第２のバッテリ１０１ｂに適用できる。 (Embodiment 8)
In this embodiment mode, other configuration examples of the battery will be described with reference to Fig. 22 and Fig. 23. The other configuration examples of the battery shown in this embodiment mode can be applied to the first battery 101a or the second battery 101b unless otherwise specified.
＜ラミネート型電池セル＞
図２２Ａ及び図２２Ｂに示す二次電池５００はラミネート型電池セルである。図２２Ａ及び図２２Ｂは、正極５０３、負極５０６、セパレータ５０７、外装体５０９、正極リード電極５１０、及び負極リード電極５１１を有する。 <Laminated battery cell>
22A and 22B is a laminated type battery cell having a positive electrode 503, a negative electrode 506, a separator 507, an outer casing 509, a positive electrode lead electrode 510, and a negative electrode lead electrode 511.
図２２Ａは正極５０３及び負極５０６の外観図を示す。正極５０３は正極集電体５５０を有し、正極活物質層５７１は正極集電体５５０の表面に形成されている。また、正極５０３は正極集電体５５０が一部露出する領域（以下、タブ領域という）を有する。負極５０６は負極集電体を有し、負極活物質層は負極集電体の表面に形成されている。また、負極５０６は負極集電体が一部露出する領域、すなわちタブ領域を有する。なお、正極及び負極が有するタブ領域の面積又は形状は、図２２Ａに示す例に限られない。 Figure 22A shows the external appearance of the positive electrode 503 and the negative electrode 506. The positive electrode 503 has a positive electrode collector 550, and a positive electrode active material layer 571 is formed on the surface of the positive electrode collector 550. The positive electrode 503 also has a region where the positive electrode collector 550 is partially exposed (hereinafter referred to as a tab region). The negative electrode 506 has a negative electrode collector, and a negative electrode active material layer is formed on the surface of the negative electrode collector. The negative electrode 506 also has a region where the negative electrode collector is partially exposed, i.e., a tab region. Note that the area or shape of the tab region of the positive electrode and the negative electrode is not limited to the example shown in Figure 22A.
＜ラミネート型電池セルの製造方法＞
図２２Ａに外観図を示すラミネート型電池セルの製造方法の一例について、図２３Ａ及び図２３Ｂを用いて説明する。 <Manufacturing method of laminated battery cell>
An example of a method for manufacturing a laminated type battery cell whose external view is shown in FIG. 22A will be described with reference to FIGS. 23A and 23B.
まず、図２３Ａで負極５０６、セパレータ５０７及び正極５０３を積層する。ここでは負極を５組、正極を４組使用する例を示す。負極とセパレータと正極からなる積層体とも呼べる。次に、正極５０３のタブ領域同士の接合と、最表面の正極のタブ領域への正極リード電極５１０の接合を行う。接合には、例えば超音波溶接等を用いればよい。同様に、負極５０６のタブ領域同士の接合と、最表面の負極のタブ領域への負極リード電極５１１の接合を行う。 First, in FIG. 23A, the negative electrode 506, the separator 507, and the positive electrode 503 are laminated. Here, an example is shown in which five pairs of negative electrodes and four pairs of positive electrodes are used. It can also be called a laminate consisting of a negative electrode, a separator, and a positive electrode. Next, the tab regions of the positive electrodes 503 are joined together, and the positive electrode lead electrode 510 is joined to the tab region of the outermost positive electrode. For example, ultrasonic welding or the like may be used for the joining. Similarly, the tab regions of the negative electrodes 506 are joined together, and the negative electrode lead electrode 511 is joined to the tab region of the outermost negative electrode.
次に、外装体５０９上に、負極５０６、セパレータ５０７及び正極５０３を配置する。 Next, the negative electrode 506, the separator 507, and the positive electrode 503 are placed on the outer casing 509.
次に、図２３Ｂに示すように、外装体５０９を破線で示した部分で折り曲げる。その後、外装体５０９の外周部を接合する。接合には例えば熱圧着等を用いればよい。この時、後に電解液を入れることができるように、外装体５０９の一部（又は一辺）に接合されない領域（以下、導入口という）を設ける。 Next, as shown in FIG. 23B, the exterior body 509 is folded at the portion indicated by the dashed line. After that, the outer periphery of the exterior body 509 is joined. For the joining, for example, thermocompression bonding or the like may be used. At this time, an area (hereinafter referred to as an inlet) that is not joined is provided on a part (or one side) of the exterior body 509 so that the electrolyte can be introduced later.
次に、外装体５０９に設けられた導入口から、電解液（図示しない。）を外装体５０９の内側へ導入する。電解液の導入は、減圧雰囲気下、或いは不活性雰囲気下で行うことが好ましい。そして最後に、導入口を接合する。このようにして、ラミネート型電池セルを作製することができる。 Next, an electrolyte (not shown) is introduced into the inside of the exterior body 509 through an inlet provided in the exterior body 509. The electrolyte is preferably introduced under a reduced pressure atmosphere or an inert atmosphere. Finally, the inlet is joined. In this manner, a laminated battery cell can be produced.
本実施の形態は、他の実施の形態と適宜組み合わせて用いることができる。 This embodiment can be used in appropriate combination with other embodiments.
（実施の形態９）
本実施の形態では、バッテリの他の構成例について図２４及び図２５を用いて説明する。本実施の形態で示すバッテリの他の構成例は、断りのない限り、第１のバッテリ１０１ａ又は第２のバッテリ１０１ｂに適用できる。 (Embodiment 9)
In this embodiment mode, other configuration examples of the battery will be described with reference to Fig. 24 and Fig. 25. The other configuration examples of the battery shown in this embodiment mode can be applied to the first battery 101a or the second battery 101b unless otherwise specified.
［角型電池セル］
図２４Ａに示す二次電池９１３は角型電池セルであり、筐体９３０の内部に端子９５１と端子９５２が設けられた捲回体９５０を有する。捲回体９５０は、筐体９３０の内部で電解液に浸される。端子９５２は、筐体９３０に接し、端子９５１は、絶縁材などを用いることにより筐体９３０に接していない。なお、図２４Ａでは、便宜のため、筐体９３０を分離して図示しているが、実際は、捲回体９５０が筐体９３０に覆われ、端子９５１及び端子９５２が筐体９３０の外に延在している。筐体９３０としては、金属材料（例えばアルミニウムなど）又は金属材料と樹脂材料との積層体を用いることができる。 [Rectangular battery cell]
The secondary battery 913 shown in FIG. 24A is a rectangular battery cell, and has a wound body 950 in which terminals 951 and 952 are provided inside a housing 930. The wound body 950 is immersed in an electrolyte inside the housing 930. The terminal 952 contacts the housing 930, and the terminal 951 does not contact the housing 930 by using an insulating material or the like. Note that in FIG. 24A, the housing 930 is shown separated for convenience, but in reality, the wound body 950 is covered by the housing 930, and the terminals 951 and 952 extend outside the housing 930. The housing 930 can be made of a metal material (e.g., aluminum) or a laminate of a metal material and a resin material.
なお、図２４Ｂに示すように、図２４Ａに示す筐体９３０を複数の材料によって形成してもよい。例えば、図２４Ｂに示す二次電池９１３は、筐体９３０ａと筐体９３０ｂが貼り合わされており、筐体９３０ａ及び筐体９３０ｂで囲まれた領域に捲回体９５０が設けられている。 As shown in FIG. 24B, the housing 930 shown in FIG. 24A may be formed from a plurality of materials. For example, the secondary battery 913 shown in FIG. 24B has housings 930a and 930b bonded together, and a wound body 950 is provided in the area surrounded by the housings 930a and 930b.
筐体９３０ａとしては、金属材料（例えばアルミニウムなど）又は金属材料と樹脂材料との積層体を用いることができる。特に、アンテナが形成される面に樹脂材料を用いることにより、二次電池９１３による電界の遮蔽を抑制できる。なお、筐体９３０ａによる電界の遮蔽が小さければ、筐体９３０ａの内部にアンテナを設けてもよい。筐体９３０ｂとしては、金属材料（例えばアルミニウムなど）又は金属材料と樹脂材料との積層体を用いることができる。 The housing 930a can be made of a metal material (such as aluminum) or a laminate of a metal material and a resin material. In particular, by using a resin material on the surface on which the antenna is formed, it is possible to suppress shielding of the electric field by the secondary battery 913. Note that if the shielding of the electric field by the housing 930a is small, the antenna may be provided inside the housing 930a. The housing 930b can be made of a metal material (such as aluminum) or a laminate of a metal material and a resin material.
さらに、捲回体９５０の構造について図２４Ｃに示す。捲回体９５０は、負極９３１と、正極９３２と、セパレータ９３３と、を有する。捲回体９５０は、セパレータ９３３を挟んで負極９３１と、正極９３２が重なり合って積層され、該積層シートを捲回させた捲回体である。なお、負極９３１と、正極９３２と、セパレータ９３３と、の積層を、さらに複数重ねてもよい。 Furthermore, the structure of the wound body 950 is shown in FIG. 24C. The wound body 950 has a negative electrode 931, a positive electrode 932, and a separator 933. The wound body 950 is a wound body in which the negative electrode 931 and the positive electrode 932 are stacked on top of each other with the separator 933 in between, and the laminated sheet is wound. Note that the stack of the negative electrode 931, the positive electrode 932, and the separator 933 may be stacked multiple times.
また角型電池セルとして、図２５Ａ乃至図２５Ｃに示すような捲回体９５０ａを有する二次電池９１３としてもよい。図２５Ａに示す捲回体９５０ａは、負極９３１と、正極９３２と、セパレータ９３３と、を有する。負極９３１は負極活物質層９３１ａを有する。正極９３２は正極活物質層９３２ａを有する。 Also, the rectangular battery cell may be a secondary battery 913 having a wound body 950a as shown in Figs. 25A to 25C. The wound body 950a shown in Fig. 25A has a negative electrode 931, a positive electrode 932, and a separator 933. The negative electrode 931 has a negative electrode active material layer 931a. The positive electrode 932 has a positive electrode active material layer 932a.
セパレータ９３３は、負極活物質層９３１ａ及び正極活物質層９３２ａよりも広い幅を有し、負極活物質層９３１ａ及び正極活物質層９３２ａと重畳するように捲回されている。また正極活物質層９３２ａよりも負極活物質層９３１ａの幅が広いことが安全性の点で好ましい。またこのような形状の捲回体９５０ａは安全性及び生産性がよく好ましい。 The separator 933 has a width wider than the negative electrode active material layer 931a and the positive electrode active material layer 932a, and is wound so as to overlap the negative electrode active material layer 931a and the positive electrode active material layer 932a. From the viewpoint of safety, it is preferable that the width of the negative electrode active material layer 931a is wider than that of the positive electrode active material layer 932a. Furthermore, a wound body 950a having such a shape is preferable because of its good safety and productivity.
図２５Ｂに示すように、負極９３１は端子９５１と電気的に接続される。端子９５１は端子９１１ａと電気的に接続される。また正極９３２は端子９５２と電気的に接続される。端子９５２は端子９１１ｂと電気的に接続される。 As shown in FIG. 25B, the negative electrode 931 is electrically connected to terminal 951. Terminal 951 is electrically connected to terminal 911a. The positive electrode 932 is electrically connected to terminal 952. Terminal 952 is electrically connected to terminal 911b.
図２５Ｃに示すように、筐体９３０により捲回体９５０ａ及び電解液が覆われ、二次電池９１３となる。筐体９３０には安全弁、過電流保護素子等を設けることが好ましい。安全弁は、電池破裂を防止するため、筐体９３０の内部が所定の内圧で開放する弁である。 As shown in FIG. 25C, the wound body 950a and the electrolyte are covered by the housing 930 to form the secondary battery 913. It is preferable to provide the housing 930 with a safety valve, an overcurrent protection element, and the like. The safety valve is a valve that opens when the inside of the housing 930 reaches a certain internal pressure to prevent the battery from exploding.
図２５Ｂに示すように二次電池９１３は複数の捲回体９５０ａを有していてもよい。複数の捲回体９５０ａを用いることで、より放電容量の大きい二次電池９１３とすることができる。図２５Ａ及び図２５Ｂに示す二次電池９１３の他の要素は、図２４Ａ乃至図２４Ｃに示す二次電池９１３の記載を参照することができる。 As shown in FIG. 25B, the secondary battery 913 may have multiple wound bodies 950a. By using multiple wound bodies 950a, the secondary battery 913 can have a larger discharge capacity. For other elements of the secondary battery 913 shown in FIGS. 25A and 25B, refer to the description of the secondary battery 913 shown in FIGS. 24A to 24C.
＜円筒型電池セル＞
図２６Ａに示す二次電池６００は円筒型電池セルである。図２６Ｂは、二次電池６００の断面を模式的に示した図である。図２６Ｂに示すように、二次電池６００は、上面に正極キャップ（電池蓋）６０１を有し、側面及び底面に電池缶（外装缶）６０２を有している。これら正極キャップと電池缶（外装缶）６０２とは、ガスケット（絶縁パッキン）６１０によって絶縁されている。 <Cylindrical battery cell>
The secondary battery 600 shown in Fig. 26A is a cylindrical battery cell. Fig. 26B is a schematic diagram showing a cross section of the secondary battery 600. As shown in Fig. 26B, the secondary battery 600 has a positive electrode cap (battery lid) 601 on the top surface, and a battery can (external can) 602 on the side and bottom surfaces. The positive electrode cap and the battery can (external can) 602 are insulated by a gasket (insulating packing) 610.
中空円柱状の電池缶６０２の内側には、帯状の正極６０４と負極６０６とがセパレータ６０５を間に挟んで捲回された電池素子が設けられている。図示しないが、電池素子はセンターピンを中心に捲回されている。電池缶６０２は、一端が閉じられ、他端が開いている。電池缶６０２には、電解液に対して耐腐食性のあるニッケル、アルミニウム、チタン等の金属、又はこれらの合金、又はこれらと他の金属との合金（例えば、ステンレス鋼等）を用いることができる。また、電解液による腐食を防ぐため、ニッケル又はアルミニウム等で電池缶６０２を被覆することが好ましい。電池缶６０２の内側において、正極、負極及びセパレータが捲回された電池素子は、対向する一対の絶縁板６０８、絶縁板６０９により挟まれている。また、電池素子が設けられた電池缶６０２の内部は、非水電解液（図示せず）が注入されている。 Inside the hollow cylindrical battery can 602, a battery element is provided in which a strip-shaped positive electrode 604 and a negative electrode 606 are wound with a separator 605 sandwiched between them. Although not shown, the battery element is wound around a center pin. One end of the battery can 602 is closed and the other end is open. For the battery can 602, metals such as nickel, aluminum, and titanium that are resistant to corrosion by the electrolyte, or alloys of these metals, or alloys of these metals with other metals (e.g., stainless steel, etc.) can be used. In addition, in order to prevent corrosion by the electrolyte, it is preferable to cover the battery can 602 with nickel, aluminum, or the like. Inside the battery can 602, the battery element in which the positive electrode, negative electrode, and separator are wound is sandwiched between a pair of opposing insulating plates 608 and 609. In addition, a nonaqueous electrolyte (not shown) is injected into the inside of the battery can 602 in which the battery element is provided.
円筒型電池セルでは正極及び負極が捲回するため、集電体の両面に活物質を形成することが好ましい。正極６０４には正極端子（正極集電リード）６０３が接続され、負極６０６には負極端子（負極集電リード）６０７が接続される。正極端子６０３は、アルミニウムなどの金属材料を用いることができる。負極端子６０７は、銅などの金属材料を用いることができる。正極端子６０３は安全弁機構６１２に、負極端子６０７は電池缶６０２の底にそれぞれ抵抗溶接される。安全弁機構６１２は、ＰＴＣ（Ｐｏｓｉｔｉｖｅ　Ｔｅｍｐｅｒａｔｕｒｅ　Ｃｏｅｆｆｉｃｉｅｎｔ）素子６１１を介して正極キャップ６０１と電気的に接続されている。安全弁機構６１２は電池の内圧の上昇が所定の閾値を超えた場合に、正極キャップ６０１と正極６０４との電気的な接続を切断するものである。また、ＰＴＣ素子６１１は温度が上昇した場合に抵抗が増大する熱感抵抗素子であり、抵抗の増大により電流量を制限して異常発熱を防止するものである。ＰＴＣ素子には、チタン酸バリウム（ＢａＴｉＯ３）系半導体セラミックス等を用いることができる。 In a cylindrical battery cell, since the positive and negative electrodes are wound, it is preferable to form an active material on both sides of the current collector. A positive electrode terminal (positive electrode current collector lead) 603 is connected to the positive electrode 604, and a negative electrode terminal (negative electrode current collector lead) 607 is connected to the negative electrode 606. The positive electrode terminal 603 can be made of a metal material such as aluminum. The negative electrode terminal 607 can be made of a metal material such as copper. The positive electrode terminal 603 is resistance-welded to a safety valve mechanism 612, and the negative electrode terminal 607 is resistance-welded to the bottom of the battery can 602. The safety valve mechanism 612 is electrically connected to the positive electrode cap 601 via a PTC (Positive Temperature Coefficient) element 611. The safety valve mechanism 612 cuts off the electrical connection between the positive electrode cap 601 and the positive electrode 604 when the rise in the internal pressure of the battery exceeds a predetermined threshold value. The PTC element 611 is a thermosensitive resistor whose resistance increases when the temperature rises, and the increase in resistance limits the amount of current to prevent abnormal heat generation. Barium titanate (BaTiO 3 ) based semiconductor ceramics or the like can be used for the PTC element.
また、図２６Ｃのように複数の二次電池６００を、導電板６１３及び導電板６１４の間に挟んで組電池６１５を構成してもよい。複数の二次電池６００は、並列接続されていてもよいし、直列接続されていてもよいし、並列に接続された後さらに直列に接続されていてもよい。複数の二次電池６００を有する組電池６１５を構成することで、大きな電力を取り出すことができる。電池パックは、組電池６１５、ＢＭＳ及び温度センサ等を有することができる。 Also, as shown in FIG. 26C, multiple secondary batteries 600 may be sandwiched between conductive plates 613 and 614 to form an assembled battery 615. The multiple secondary batteries 600 may be connected in parallel, in series, or in parallel and then further in series. By forming an assembled battery 615 having multiple secondary batteries 600, a large amount of power can be extracted. The battery pack may include the assembled battery 615, a BMS, a temperature sensor, etc.
図２６Ｄは組電池６１５の上面図である。図を明瞭にするために導電板６１３を点線で示した。図２６Ｄに示すように組電池６１５は、複数の二次電池６００を電気的に接続する導線６１６を有していてもよい。導線６１６上に導電板を重畳して設けることができる。また複数の二次電池６００の間に温度制御装置として冷却装置６１７を有してもよい。二次電池６００が過熱されたときは、冷却装置６１７により冷却することができる。温度制御装置として加温装置を用いると、二次電池６００が冷えすぎているときに加熱することもできる。そのため組電池６１５の性能が外気温に影響されにくくなる。 Figure 26D is a top view of the battery pack 615. To make the figure clearer, the conductive plate 613 is shown with a dotted line. As shown in Figure 26D, the battery pack 615 may have a conductor 616 that electrically connects the multiple secondary batteries 600. A conductive plate can be superimposed on the conductor 616. A cooling device 617 may also be provided between the multiple secondary batteries 600 as a temperature control device. When the secondary batteries 600 overheat, they can be cooled by the cooling device 617. If a heating device is used as a temperature control device, the secondary batteries 600 can also be heated when they are too cold. This makes the performance of the battery pack 615 less susceptible to the effects of the outside air temperature.
本実施の形態は、他の実施の形態と適宜組み合わせて用いることができる。 This embodiment can be used in appropriate combination with other embodiments.
（実施の形態１０）
本実施の形態では、本発明の一態様であるバッテリ制御システム等を搭載した車両等について、図２７を用いて説明する。 (Embodiment 10)
In this embodiment, a vehicle or the like equipped with a battery control system or the like which is one embodiment of the present invention will be described with reference to FIG.
図２７Ａに示す自動車８４００は、走行のための動力源として電気モータを用いる電気自動車（ＥＶ）である。自動車８４００は本発明の一態様であるバッテリ制御システムを有し、バッテリの充放電を制御すると好ましい。当該バッテリの動力は電気モータ８４０６を駆動することに利用されるが、ヘッドライト８４０１又はルームライト（図示せず）などの発光装置に電力を供給してもよい。勿論、ヘッドライト８４０１又はルームライト（図示せず）などの発光装置には１２Ｖバッテリから電力を供給してもよい。 The automobile 8400 shown in FIG. 27A is an electric vehicle (EV) that uses an electric motor as a power source for traveling. The automobile 8400 preferably has a battery control system, which is one aspect of the present invention, and controls the charging and discharging of the battery. The power of the battery is used to drive the electric motor 8406, but may also be used to supply power to a light-emitting device such as a headlight 8401 or a room light (not shown). Of course, power may also be supplied from a 12V battery to a light-emitting device such as a headlight 8401 or a room light (not shown).
また、当該バッテリの動力は、自動車８４００が有するスピードメーター、タコメーターなどの表示装置に電力を供給してもよい。勿論、スピードメーター、タコメーターなどの表示装置には１２Ｖバッテリから電力を供給してもよい。 Furthermore, the power of the battery may be used to supply power to display devices such as a speedometer and a tachometer of the automobile 8400. Of course, power may be supplied to display devices such as a speedometer and a tachometer from a 12V battery.
また、当該バッテリの動力は、自動車８４００が有するナビゲーションシステムなどの半導体装置に電力を供給してもよい。勿論、ナビゲーションシステムなどの半導体装置には１２Ｖバッテリから電力を供給してもよい。 Furthermore, the power of the battery may be used to supply power to semiconductor devices such as a navigation system included in the automobile 8400. Of course, power may be supplied to semiconductor devices such as a navigation system from a 12V battery.
図２７Ｂに示す自動車８５００はプラグインハイブリッド車（ＰＨＶ）であり、自動車８５００が有するバッテリにプラグイン方式又は非接触給電方式等により外部の充電設備から電力供給を受けて、充電することができるハイブリッド車の例である。自動車８５００は本発明の一態様であるバッテリ制御システムを有し、バッテリの充放電を制御すると好ましい。 The automobile 8500 shown in FIG. 27B is a plug-in hybrid vehicle (PHV), and is an example of a hybrid vehicle that can charge the battery of the automobile 8500 by receiving power from an external charging facility using a plug-in method or a contactless power supply method. The automobile 8500 preferably has a battery control system, which is one aspect of the present invention, and controls the charging and discharging of the battery.
図２７Ｂに、地上設置型の充電スタンド８０２１から自動車８５００に搭載されたバッテリ８０２４（第１のバッテリと第２のバッテリが含まれる）に、ケーブル８０２２を介して充電を行っている状態を示す。充電スタンド８０２１は、商用施設に設けられた充電ステーションでもよく、また家庭の電源であってもよい。 FIG. 27B shows a state in which a battery 8024 (including a first battery and a second battery) mounted on an automobile 8500 is being charged via a cable 8022 from a ground-mounted charging stand 8021. The charging stand 8021 may be a charging station provided in a commercial facility, or may be a home power source.
例えば、プラグイン技術によって、外部からの電力供給により自動車８５００に搭載されたバッテリ８０２４を充電することができる。充電は、ＡＣＤＣコンバータ等の変換装置を介して、交流電力を直流電力に変換して行うことができる。ＡＣＤＣコンバータ等の変換装置は自動車８５００が備えていてもよいし、充電スタンド８０２１が備えていてもよい。充電スタンド８０２１が備えた場合、急速充電が可能になる。なお、充電スタンド８０２１に関する説明は、図２７Ａに示した自動車８４００に対して適用することができる。 For example, by using plug-in technology, the battery 8024 mounted on the automobile 8500 can be charged by an external power supply. Charging can be performed by converting AC power to DC power via a conversion device such as an AC-DC converter. The conversion device such as an AC-DC converter may be provided in the automobile 8500 or in the charging stand 8021. When the charging stand 8021 is provided with the conversion device, rapid charging becomes possible. Note that the description regarding the charging stand 8021 can be applied to the automobile 8400 shown in FIG. 27A.
また、図示しないが、充電装置を車両に搭載する場合、地上の送電装置から電力を非接触で供給して充電することもできる。この非接触給電方式の場合には、道路又は外壁に送電装置を組み込むことで、停車中に限らず走行中に充電を行うこともできる。また、この非接触給電の方式を利用して、車両同士で電力の送受信を行ってもよい。さらに、車両の外装部に太陽電池を設け、停車時又は走行時に二次電池の充電を行ってもよい。このような非接触での電力の供給には、電磁誘導方式又は磁界共鳴方式を用いることができる。なお、非接触で電力を送受信することに関する説明は、図２７Ａに示した自動車８４００に対して適用することができる。 In addition, although not shown, when a charging device is mounted on a vehicle, charging can be performed by supplying power contactlessly from a ground power transmission device. In the case of this contactless power supply method, by incorporating a power transmission device into a road or an exterior wall, charging can be performed not only while the vehicle is stopped but also while it is moving. This contactless power supply method can also be used to transmit and receive power between vehicles. Furthermore, a solar cell can be provided on the exterior of the vehicle to charge the secondary battery when the vehicle is stopped or moving. An electromagnetic induction method or a magnetic field resonance method can be used for such contactless power supply. Note that the explanation regarding contactless transmission and reception of power can be applied to the automobile 8400 shown in FIG. 27A.
また、図２７Ｃは、二輪車の一例であり、スクータ８６００を示す。スクータ８６００は本発明の一態様であるバッテリ制御システムを有し、バッテリの充放電を制御すると好ましい。 Figure 27C shows a scooter 8600, which is an example of a two-wheeled vehicle. The scooter 8600 preferably has a battery control system, which is one aspect of the present invention, and controls the charging and discharging of the battery.
スクータ８６００は、バッテリ８６０２（第１のバッテリと第２のバッテリが含まれる）、サイドミラー８６０１、方向指示灯８６０３を備える。バッテリ８６０２は、方向指示灯８６０３に電気を供給することができる。勿論、方向指示灯８６０３には１２Ｖバッテリから電力を供給してもよい。 The scooter 8600 includes a battery 8602 (including a first battery and a second battery), a side mirror 8601, and a turn signal light 8603. The battery 8602 can supply electricity to the turn signal light 8603. Of course, the turn signal light 8603 may be supplied with power from a 12V battery.
また、図２７Ｃに示すスクータ８６００は、座席下収納８６０４に、バッテリ８６０２を収納することができる。バッテリ８６０２は、取り外し可能な機構を備えると好ましく、この場合充電時にバッテリ８６０２を屋内に持って運び、充電し、走行する前に座席下収納８６０４へ収納すればよい。 The scooter 8600 shown in FIG. 27C can also store a battery 8602 in the under-seat storage 8604. The battery 8602 is preferably equipped with a removable mechanism, in which case the battery 8602 can be brought indoors for charging, charged, and then stored in the under-seat storage 8604 before riding.
本実施の形態は、他の実施の形態と適宜組み合わせて実施することが可能である。 This embodiment can be implemented in appropriate combination with other embodiments.
（実施の形態１１）
本実施の形態では、本発明の一態様である車両から、電力を建築物へ供給する例について図２８を用いて説明する。 (Embodiment 11)
In this embodiment, an example of supplying power from a vehicle, which is one embodiment of the present invention, to a building will be described with reference to FIG. 28 .
図２８に示す住宅２６００は、車両２６０３が有するバッテリ（第１のバッテリと第２のバッテリが含まれる）と、変換器２６０４を介して電気的に接続されている。変換器２６０４は車両２６０３が有するバッテリが直流電流であるため、住宅２６００用の交流電流へ変換する機能を有する。車両２６０３を駐車しているとき、車両２６０３のバッテリの電力を住宅２６００で使用することができる。本発明の一形態である車両２６０３は、変換器２６０４を備えることで、ビークルトゥホームを実行することができる。 The house 2600 shown in FIG. 28 is electrically connected to the batteries (including a first battery and a second battery) of the vehicle 2603 via a converter 2604. The converter 2604 has a function of converting the direct current of the battery of the vehicle 2603 into alternating current for the house 2600. When the vehicle 2603 is parked, the power of the battery of the vehicle 2603 can be used by the house 2600. The vehicle 2603, which is one embodiment of the present invention, can perform vehicle-to-home by being equipped with the converter 2604.
さらに住宅２６００は、蓄電装置２６１２と、ソーラーパネル２６１０を有すると好ましい。蓄電装置２６１２は、ソーラーパネル２６１０と配線２６１１等を介して電気的に接続されている。蓄電装置２６１２は、床下空間部に設置されることが好ましい。床下空間部に設置することにより、床上の空間を有効的に利用することができる。あるいは、蓄電装置２６１２は床上に設置されてもよい。また蓄電装置２６１２は、変換器２６０４とも電気的に接続されている。蓄電装置２６１２が本発明の一態様であるバッテリ制御システムを備えていてもよい。 Furthermore, the house 2600 preferably has a power storage device 2612 and a solar panel 2610. The power storage device 2612 is electrically connected to the solar panel 2610 via wiring 2611 or the like. The power storage device 2612 is preferably installed in the underfloor space. By installing it in the underfloor space, the space above the floor can be effectively used. Alternatively, the power storage device 2612 may be installed on the floor. The power storage device 2612 is also electrically connected to the converter 2604. The power storage device 2612 may be equipped with a battery control system which is one embodiment of the present invention.
ソーラーパネル２６１０で得た電力は、蓄電装置２６１２に充電することができる。また蓄電装置２６１２に蓄えられた電力は、変換器２６０４を介して車両２６０３が有するバッテリへ蓄えることができる。蓄電装置２６１２に蓄えられた電力は、住宅２６００内の他の電子機器にも電力を供給することができる。 The power obtained by the solar panel 2610 can be charged to the power storage device 2612. The power stored in the power storage device 2612 can also be stored in a battery in the vehicle 2603 via the converter 2604. The power stored in the power storage device 2612 can also be supplied to other electronic devices in the house 2600.
ビークルトゥホームにより、停電などにより商用電源から電力の供給が受けられない時でも、住宅２６００内の他の電子機器の利用が可能になる。 Vehicle-to-home makes it possible to use other electronic devices in the house 2600 even when power cannot be supplied from the commercial power source due to a power outage or other reason.
本実施の形態は、他の実施の形態と適宜組み合わせて実施することが可能である。 This embodiment can be implemented in appropriate combination with other embodiments.
［符号の説明］
１０　　バッテリ制御システム
１１：電気自動車、１２：充電制御回路、１３：タイヤ、１４：モータ制御回路、１５：駆動用モータ、１８：変換器、１９ａ：普通充電用充電口、１９ｂ：急速充電用充電口、１９：充電口、２１：ＶＣＵ、２５：ＣＡＮ、２３：ヘッドライト、２４：補助バッテリ、２７：シャーシ、２８：容器、３０：充電スタンド、３１：交流電源、３３：コンバータ、３４：インバータ、３５：トランス回路、３６：整流回路、３７：コネクタ、５１：単電池、５２：組電池、１０１ａ：第１のバッテリ、１０１ｂ：第２のバッテリ、１０１：バッテリ、１０２ａ：第１のセンサ回路、１０２ｂ：第２のセンサ回路、１０３ａ：第１の電圧センサ、１０３ｂ：第２の電圧センサ、１０４ａ：第１の電流センサ、１０４ｂ：第２の電流センサ、１０６ａ：第１の回路、１０６ｂ：第２の回路、１０７ａ：第１のＤＣ／ＤＣ回路、１０７ｂ：第２のＤＣ／ＤＣ回路、１０８ａ：第１のダイオード、１０８ｂ：第２のダイオード、１５０ａ：マイコン、１５０ｂ：保護ＩＣ、１５０ｂｘ：保護ＩＣ、１５０ｂｙ：保護ＩＣ、１５０：ＢＭＳ、１５１：電圧監視ソフト、１５２：ＳＰＣ演算ソフト、１５３：絶縁抵抗検知ソフト、１５４：電流検知ソフト、１５５：温度調整制御、１５６：ＣＡＮソフト、１５７：リレーシーケンスソフト [Explanation of symbols]
10 Battery control system 11: electric vehicle, 12: charging control circuit, 13: tire, 14: motor control circuit, 15: drive motor, 18: converter, 19a: normal charging port, 19b: quick charging port, 19: charging port, 21: VCU, 25: CAN, 23: headlight, 24: auxiliary battery, 27: chassis, 28: container, 30: charging stand, 31: AC power source, 33: converter, 34: inverter, 35: transformer circuit, 36: rectifier circuit, 37: connector, 51: single cell, 52: battery pack, 101a: first battery, 101b: second battery, 101: battery, 102a: first sensor circuit, 102b: second sensor circuit, 103a: first voltage sensor, 103b: second voltage sensor, 104a: first current sensor, 104b: second current sensor, 106a: first circuit, 106b: second circuit, 107a: first DC/DC circuit, 107b: second DC/DC circuit, 108a: first diode, 108b: second diode, 150a: microcomputer, 150b: protection IC, 150bx: protection IC, 150by: protection IC, 150: BMS, 151: voltage monitoring software, 152: SPC calculation software, 153: insulation resistance detection software, 154: current detection software, 155: temperature adjustment control, 156: CAN software, 157: relay sequence software

Claims (14)

  1. 　第１の正極活物質を有する第１のバッテリと、
    　第２の正極活物質を有する第２のバッテリと、
    　前記第１のバッテリと電気的に接続された、第１のセンサ回路と、
    　前記第２のバッテリと電気的に接続された、第２のセンサ回路と、
    　前記第１のバッテリと電気的に接続された、第１のＤＣ／ＤＣコンバータと、
    　前記第２のバッテリと電気的に接続された、第２のＤＣ／ＤＣコンバータと、
    　前記第１のセンサ回路、前記第２のセンサ回路、前記第１のＤＣ／ＤＣコンバータ、及び前記第２のＤＣ／ＤＣコンバータと電気的に接続された、マイコンと、を有し、
    　前記マイコンは、前記第１のセンサ回路、又は前記第２のセンサ回路から得られた信号に基づき、前記第１のＤＣ／ＤＣコンバータからのモータ制御回路への出力と、前記第２のＤＣ／ＤＣコンバータからの前記モータ制御回路への出力とを決定する機能を有する、
    　バッテリ制御システム。     a first battery having a first positive electrode active material;
    a second battery having a second positive electrode active material;
    a first sensor circuit electrically connected to the first battery;
    a second sensor circuit electrically connected to the second battery;
    a first DC/DC converter electrically connected to the first battery;
    a second DC/DC converter electrically connected to the second battery;
    a microcomputer electrically connected to the first sensor circuit, the second sensor circuit, the first DC/DC converter, and the second DC/DC converter;
    the microcomputer has a function of determining an output from the first DC/DC converter to a motor control circuit and an output from the second DC/DC converter to the motor control circuit based on a signal obtained from the first sensor circuit or the second sensor circuit;
    Battery control system.
  2. 　第１の正極活物質を有する第１のバッテリと、
    　第２の正極活物質を有する第２のバッテリと、
    　前記第１のバッテリと電気的に接続された、第１のセンサ回路と、
    　前記第２のバッテリと電気的に接続された、第２のセンサ回路と、
    　前記第１のバッテリと電気的に接続された、第１のＤＣ／ＤＣコンバータと、
    　前記第２のバッテリと電気的に接続された、第２のＤＣ／ＤＣコンバータと、
    　前記第１のセンサ回路、前記第２のセンサ回路、前記第１のＤＣ／ＤＣコンバータ、及び前記第２のＤＣ／ＤＣコンバータと電気的に接続された、マイコンと、
    　前記マイコンと電気的に接続された保護ＩＣと、を有し、
    　前記マイコンは、前記第１のセンサ回路、又は前記第２のセンサ回路から得られた信号に基づき、前記第１のＤＣ／ＤＣコンバータからのモータ制御回路への出力と、前記第２のＤＣ／ＤＣコンバータからの前記モータ制御回路への出力とを決定する機能を有する、
    　バッテリ制御システム。     a first battery having a first positive electrode active material;
    a second battery having a second positive electrode active material;
    a first sensor circuit electrically connected to the first battery;
    a second sensor circuit electrically connected to the second battery;
    a first DC/DC converter electrically connected to the first battery;
    a second DC/DC converter electrically connected to the second battery;
    a microcomputer electrically connected to the first sensor circuit, the second sensor circuit, the first DC/DC converter, and the second DC/DC converter;
    a protection IC electrically connected to the microcomputer;
    the microcomputer has a function of determining an output from the first DC/DC converter to a motor control circuit and an output from the second DC/DC converter to the motor control circuit based on a signal obtained from the first sensor circuit or the second sensor circuit;
    Battery control system.
  3. 　請求項２において、
    　前記マイコン及び前記保護ＩＣを有するバッテリマネジメントシステムを有する、
    　バッテリ制御システム。     In claim 2,
    a battery management system including the microcomputer and the protection IC;
    Battery control system.
  4. 　請求項３において、
    　前記保護ＩＣは前記第１のバッテリが有する単電池、又は前記第２のバッテリが有する単電池と電気的に接続されている、
    　バッテリ制御システム。     In claim 3,
    the protection IC is electrically connected to a cell of the first battery or a cell of the second battery;
    Battery control system.
  5. 　請求項１又は請求項２において、
    　前記第１の正極活物質はオリビン型の結晶構造を有し、
    　前記第２の正極活物質は層状岩塩型の結晶構造を有する、
    　バッテリ制御システム。     In claim 1 or 2,
    the first positive electrode active material has an olivine type crystal structure,
    The second positive electrode active material has a layered rock salt type crystal structure.
    Battery control system.
  6. 　請求項１又は請求項２において、
    　さらに第１の回路及び第２の回路を有し、
    　前記第１の回路は、前記第１のバッテリと、充電制御回路との間に位置し、
    　前記第２の回路は、前記第２のバッテリと、前記充電制御回路との間に位置し、
    　前記第１の回路及び前記第２の回路は、前記第１のバッテリの電力を前記第２のバッテリへ転送する機能を有する、
    　バッテリ制御システム。     In claim 1 or 2,
    further comprising a first circuit and a second circuit;
    the first circuit is located between the first battery and a charge control circuit;
    the second circuit is located between the second battery and the charge control circuit;
    the first circuit and the second circuit have a function of transferring power of the first battery to the second battery;
    Battery control system.
  7. 　請求項１又は請求項２において、
    　さらに第１の回路及び第２の回路を有し、
    　前記第１の回路は、前記第１のバッテリと、充電制御回路との間に位置し、
    　前記第２の回路は、前記第２のバッテリと、前記充電制御回路との間に位置し、
    　前記第１の回路及び前記第２の回路は、前記第２のバッテリの電力を前記第１のバッテリへ転送する機能を有する、
    　バッテリ制御システム。     In claim 1 or 2,
    further comprising a first circuit and a second circuit;
    the first circuit is located between the first battery and a charge control circuit;
    the second circuit is located between the second battery and the charge control circuit;
    the first circuit and the second circuit have a function of transferring power of the second battery to the first battery;
    Battery control system.
  8. 　請求項１又は請求項２において、前記第１のセンサ回路は、前記第１のバッテリが有する単電池と電気的に接続された、第１の電流センサを有する、バッテリ制御システム。 The battery control system according to claim 1 or 2, wherein the first sensor circuit has a first current sensor electrically connected to a single cell of the first battery.
  9. 　請求項１又は請求項２において、前記第１のセンサ回路は、前記第１のバッテリが有する単電池と電気的に接続された、第１の電圧センサを有する、バッテリ制御システム。 The battery control system according to claim 1 or 2, wherein the first sensor circuit has a first voltage sensor electrically connected to a single cell of the first battery.
  10. 　請求項１又は請求項２において、前記第２のセンサ回路は、前記第２のバッテリが有する単電池と電気的に接続された、第２の電流センサを有する、バッテリ制御システム。 The battery control system according to claim 1 or 2, wherein the second sensor circuit has a second current sensor electrically connected to a single cell of the second battery.
  11. 　請求項１又は請求項２において、前記第２のセンサ回路は、前記第２のバッテリが有する単電池と電気的に接続された、第２の電圧センサを有する、バッテリ制御システム。 The battery control system according to claim 1 or 2, wherein the second sensor circuit has a second voltage sensor electrically connected to a single cell of the second battery.
  12. 　請求項２において、前記マイコンは、前記第１のバッテリのｄＱ／ｄＶ曲線に基づいて、前記第１のＤＣ／ＤＣコンバータの出力と、前記第２のＤＣ／ＤＣコンバータの出力とを制御する機能を有する、バッテリ制御システム。 A battery control system according to claim 2, wherein the microcomputer has a function of controlling the output of the first DC/DC converter and the output of the second DC/DC converter based on the dQ/dV curve of the first battery.
  13. 　請求項２において、前記マイコンは、前記第２のバッテリのｄＱ／ｄＶ曲線に基づいて、前記第１のＤＣ／ＤＣコンバータの出力と、前記第２のＤＣ／ＤＣコンバータの出力とを制御する機能を有する、バッテリ制御システム。 A battery control system according to claim 2, wherein the microcomputer has a function of controlling the output of the first DC/DC converter and the output of the second DC/DC converter based on the dQ/dV curve of the second battery.
  14. 　請求項１又は請求項２に記載されたバッテリ制御システムを搭載した車両。 A vehicle equipped with a battery control system according to claim 1 or 2.
PCT/IB2023/060835 2022-11-03 2023-10-27 Battery control system and vehicle WO2024095111A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017139911A (en) * 2016-02-04 2017-08-10 本田技研工業株式会社 Power storage device, transportation equipment having the same, determination method for determining correlation information between soc and ocv of storage battery, and program for determining correlation information
WO2019220906A1 (en) * 2018-05-14 2019-11-21 本田技研工業株式会社 Power supply system
WO2022185152A1 (en) * 2021-03-05 2022-09-09 株式会社半導体エネルギー研究所 Method for charging secondary battery

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017139911A (en) * 2016-02-04 2017-08-10 本田技研工業株式会社 Power storage device, transportation equipment having the same, determination method for determining correlation information between soc and ocv of storage battery, and program for determining correlation information
WO2019220906A1 (en) * 2018-05-14 2019-11-21 本田技研工業株式会社 Power supply system
WO2022185152A1 (en) * 2021-03-05 2022-09-09 株式会社半導体エネルギー研究所 Method for charging secondary battery

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