WO2024003662A1 - Batterie secondaire et procédé de production de matériau actif d'électrode positive - Google Patents

Batterie secondaire et procédé de production de matériau actif d'électrode positive Download PDF

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WO2024003662A1
WO2024003662A1 PCT/IB2023/056234 IB2023056234W WO2024003662A1 WO 2024003662 A1 WO2024003662 A1 WO 2024003662A1 IB 2023056234 W IB2023056234 W IB 2023056234W WO 2024003662 A1 WO2024003662 A1 WO 2024003662A1
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positive electrode
active material
secondary battery
electrode active
nickel
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PCT/IB2023/056234
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English (en)
Japanese (ja)
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山崎舜平
池田隆之
横溝和音
小國哲平
栗城和貴
吉谷友輔
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株式会社半導体エネルギー研究所
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • One embodiment of the present invention relates to a product, a method, or a manufacturing method. Alternatively, the invention relates to a process, machine, manufacture, or composition of matter.
  • One embodiment of the present invention relates to a power storage device including a secondary battery, a semiconductor device, a display device, a light emitting device, a lighting device, an electronic device, or a manufacturing method thereof.
  • electronic equipment refers to all devices that have a power storage device, and an electro-optical device that has a power storage device, an information terminal device that has a power storage device, etc. are all electronic devices.
  • lithium ion secondary batteries lithium ion capacitors
  • air batteries air batteries
  • all-solid-state batteries lithium ion secondary batteries
  • demand for high-output, high-capacity lithium-ion secondary batteries is rapidly expanding along with the development of the semiconductor industry, and they have become indispensable in today's information society as a source of rechargeable energy. .
  • Non-Patent Documents 1 to 3 fluorides such as fluorite (calcium fluoride) have been used as fluxing agents in iron manufacturing and the like for a long time, and their physical properties have been studied (Non-Patent Documents 1 to 3).
  • Non-Patent Document 2 has a description regarding the physical properties of nickel fluoride
  • Non-Patent Document 3 has a description regarding the physical properties of aluminum fluoride.
  • Non-Patent Document 4 It is also known that lithium ion secondary batteries go through several states and reach thermal runaway when the temperature rises.
  • An object of one embodiment of the present invention is to provide a positive electrode active material that does not easily deteriorate and a method for manufacturing the same. Another object of the present invention is to provide a novel positive electrode active material and a method for producing the same. Another object of the present invention is to provide a highly safe or reliable secondary battery and a method for producing the same. Another object of the present invention is to provide a secondary battery that does not easily deteriorate and a method for manufacturing the same. Another object of the present invention is to provide a long-life secondary battery and a method for manufacturing the same. Another object of the present invention is to provide a novel secondary battery and a method for manufacturing the same.
  • NCM in which a large amount of nickel is used has a problem in that oxygen is easily desorbed, especially at high temperatures, and deterioration is likely to occur.
  • transition metals M typified by nickel and manganese, enter lithium sites where lithium ions are inserted or desorbed during charging and discharging.
  • a plurality of primary particles may aggregate to form secondary particles.
  • the a-axis length and/or c-axis length of the crystals of the primary particles of NCM changes, and the volume expands or contracts.
  • the air gap becomes larger. This causes cracks or refinement of the secondary particles.
  • the voids between the primary particles herein do not necessarily mean spaces.
  • the electrolyte may be present in the gap. In the case of an all-solid-state battery, it is a space.
  • an additive element such as one or more selected from fluorine, aluminum, magnesium, titanium, and calcium is added to NCM.
  • magnesium can be added to zero relative to the transition metal M (sum of nickel, cobalt, and manganese) in the composite oxide so that the desired amount is contained by the practitioner. It is desirable to add it by weighing in the range of .5 atomic % or more and 3 atomic % or less.
  • a secondary particle is an aggregate of multiple primary particles, and there may be gaps between the primary particles within the secondary particle.
  • primary particles include polycrystals or single crystals.
  • a nickel compound also called a precursor
  • a mixture of the nickel compound and a lithium compound is mixed.
  • an additional element source is mixed and heated at a second temperature higher than the first temperature to produce a positive electrode active material.
  • an aqueous solution containing a water-soluble salt of nickel, cobalt, and manganese, and an alkaline solution are supplied to the reaction tank, and mixed inside the reaction tank. to precipitate a compound containing at least nickel, cobalt, and manganese, heat the first mixture of the compound and the lithium compound at a first heating temperature, crush or crush it, and then further heat it for a second time.
  • This is a method for producing a positive electrode active material, in which a second mixture obtained by heating a crushed or pulverized first mixture and an additive element source is heated at a third heating temperature.
  • Another configuration disclosed in this specification is to obtain a nickel compound (also referred to as a precursor) containing nickel, cobalt, and manganese using a coprecipitation method, and then add the nickel compound, lithium compound, and additional element source;
  • a positive electrode active material is produced by heating the mixture at a first temperature and pulverizing or crushing the mixture.
  • an aqueous solution containing a water-soluble salt of nickel, cobalt, and manganese, and an alkaline solution are supplied to the reaction tank, and mixed inside the reaction tank. to precipitate a compound containing at least nickel, cobalt, and manganese, and heat the first mixture of the compound, lithium compound, and additive element source at a first heating temperature to crush or crush the compound, and then further Preparation of a positive electrode active material by heating a second mixture obtained by heating at a second heating temperature and mixing a crushed or pulverized first mixture and an additive element source at a third heating temperature. It's a method.
  • heating is performed at a second temperature higher than the first temperature, and the mixing state of the mixture is improved by performing the heat treatment twice in total. Therefore, when a secondary battery is produced, voids in the secondary particles can be reduced. Further, by performing the heat treatment a total of two times, the crystallinity of the positive electrode active material can be improved.
  • the range of the first heating temperature is from 400°C to 750°C.
  • the range of the second heating temperature and the third heating temperature is higher than 750°C and lower than 1050°C.
  • an aqueous solution containing a water-soluble salt of nickel, a water-soluble cobalt salt, and a water-soluble manganese salt and an alkaline solution are supplied to a reaction tank and mixed inside the reaction tank. to precipitate a nickel compound (hydroxide containing cobalt, manganese, and nickel).
  • the reaction may be referred to as a neutralization reaction, an acid-base reaction, or a coprecipitation reaction, and the compound containing at least nickel, cobalt, and manganese is a nickel-cobalt-manganese compound containing at most cobalt, or a nickel-cobalt-manganese compound of NCM.
  • a precursor When referred to as a precursor. Thereafter, a mixture of the nickel compound and the lithium compound is obtained.
  • aqueous solution containing the water-soluble salt of nickel a nickel sulfate aqueous solution or a nickel nitrate aqueous solution can be used.
  • an aqueous cobalt sulfate solution or an aqueous cobalt nitrate solution can be used.
  • an aqueous manganese sulfate solution or an aqueous manganese nitrate solution can be used.
  • the pH of the mixed solution inside the reaction tank is preferably 9.0 or more and 12.0 or less, more preferably 10.0 or more and 11.5 or less.
  • a chelate aqueous solution it makes it easier to control the pH of the mixed liquid present inside the reaction tank when obtaining the cobalt compound. Further, it is preferable to use a chelate aqueous solution because it can suppress unnecessary generation of crystal nuclei and promote growth. When the generation of unnecessary nuclei is suppressed, the generation of fine particles is suppressed, so that a composite oxide with a good particle size distribution can be obtained. In addition, by using an aqueous chelate solution, the acid-base reaction can be delayed, and the reaction proceeds gradually, making it possible to obtain nearly spherical secondary particles.
  • Glycine has the effect of keeping the pH constant at a pH of 9.0 to 10.0 and around it, and by using a glycine aqueous solution as the chelate aqueous solution, the pH of the reaction tank when obtaining the above cobalt compound can be adjusted. is preferable because it becomes easier to control.
  • the glycine concentration of the glycine aqueous solution is preferably 0.05 mol/L or more and 0.09 mol/L or less in the aqueous solution.
  • the positive electrode active material obtained by the above method has secondary particles, and the secondary particles have a plurality of primary particles.
  • the positive electrode active material obtained by the above method has a crystal with a hexagonal layered structure, and the crystal is not limited to a single crystal (also called a crystallite), but in the case of a polycrystal, several crystallites are gathered together.
  • Form primary particles refers to a particle that is recognized as a single particle during SEM observation.
  • secondary particles refer to aggregates of primary particles.
  • the bonding force acting between a plurality of primary particles does not matter. It may be a covalent bond, an ionic bond, a hydrophobic interaction, a van der Waals force, or any other intermolecular interaction, or a plurality of bonding forces may be at work.
  • secondary particles may be formed.
  • the positive electrode active material has secondary particles, the secondary particles have a plurality of primary particles, and at least one of the plurality of primary particles has a layer containing a large amount of additive elements on the surface layer.
  • the thickness of the layer containing a large amount of additive elements is 1 nm or more and 10 nm or less.
  • a secondary battery using the above positive electrode active material is also one of the configurations disclosed in this specification.
  • a secondary battery has a positive electrode having a positive electrode active material and a negative electrode having a negative electrode active material. Furthermore, a separator is provided between the positive electrode and the negative electrode. The separator is used to prevent short circuits, and can provide a highly safe or reliable secondary battery.
  • Another configuration disclosed in this specification supplies an aqueous solution containing a water-soluble salt of a water-soluble salt of nickel, a water-soluble salt of cobalt, and a water-soluble salt of manganese to the reaction tank, and an alkaline solution,
  • a composite hydroxide containing at least nickel, cobalt, and manganese is precipitated by mixing inside a reaction tank, and a first heating is applied to the mixture of the composite hydroxide, the lithium compound, and the additive element source.
  • This is a method for producing a positive electrode active material, in which, after crushing or crushing, a second heating is further performed to crush or crush.
  • the additive element source is preferably one or more selected from a fluorine source, an aluminum source, a magnesium source, a titanium source, and a calcium source.
  • a cathode active material that does not easily deteriorate and a method for producing the same can be provided.
  • a novel positive electrode active material and a method for producing the same can be provided.
  • a highly safe or reliable secondary battery and a method for manufacturing the same can be provided.
  • a long-life secondary battery can be provided.
  • a novel secondary battery and a method for producing the same can be provided.
  • FIG. 1A and FIG. 1B are calculation model diagrams comparing the energy difference between Li 2 O generation and LiF generation in the positive electrode active material.
  • 2A to 2E are calculation model diagrams in which the surface of a composite oxide is coated with AlF 3 and LiF.
  • FIG. 3A is a schematic diagram showing the appearance of secondary particles
  • FIG. 3B is a schematic diagram showing an example of a cross section of the secondary particles.
  • FIG. 4A is a diagram showing an example of a cross section of a secondary particle
  • FIG. 4B is a schematic diagram showing an example of a cross section of a secondary particle.
  • FIGS. 5A and 5B are diagrams showing an example of a cross section of a single particle.
  • FIG. 6A and 6B are an example of a flow diagram of a manufacturing process illustrating one embodiment of the present invention.
  • FIG. 7 is an example of a flow diagram of a manufacturing process illustrating one embodiment of the present invention.
  • FIG. 8 is a phase diagram showing the relationship between the composition and temperature of lithium fluoride and magnesium fluoride.
  • FIG. 9 is a phase diagram showing the relationship between the composition and temperature of lithium fluoride and nickel fluoride.
  • FIG. 10 is a phase diagram showing the relationship between the composition and temperature of lithium fluoride and aluminum fluoride.
  • FIG. 11A is an exploded perspective view of a coin-type secondary battery
  • FIG. 11B is a perspective view of the coin-type secondary battery
  • FIG. 11C is a cross-sectional perspective view thereof.
  • FIG. 11A is an exploded perspective view of a coin-type secondary battery
  • FIG. 11B is a perspective view of the coin-type secondary battery
  • FIG. 11C is a cross-sectional perspective view thereof.
  • FIG. 12A shows an example of a cylindrical secondary battery.
  • FIG. 12B shows an example of a cylindrical secondary battery.
  • FIG. 12C shows an example of a plurality of cylindrical secondary batteries.
  • FIG. 12D shows an example of a power storage system having a plurality of cylindrical secondary batteries.
  • 13A and 13B are diagrams illustrating an example of a secondary battery, and
  • FIG. 13C is a diagram illustrating the inside of the secondary battery.
  • 14A to 14C are diagrams illustrating examples of secondary batteries.
  • 15A and 15B are diagrams showing the appearance of a secondary battery.
  • 16A to 16C are diagrams illustrating a method for manufacturing a secondary battery.
  • FIG. 17A is a perspective view of a battery pack showing one embodiment of the present invention, FIG.
  • FIG. 17B is a block diagram of the battery pack
  • FIG. 17C is a block diagram of a vehicle having the battery pack
  • 18A to 18D are diagrams illustrating an example of a transportation vehicle.
  • FIG. 18E is a diagram illustrating an example of an artificial satellite.
  • FIG. 19A is a diagram showing an electric bicycle
  • FIG. 19B is a diagram showing a secondary battery of the electric bicycle
  • FIG. 19C is a diagram explaining a scooter.
  • 20A to 20D are diagrams illustrating an example of an electronic device.
  • FIG. 21 is a graph showing the temperature rise of the secondary battery.
  • FIGS. 22A to 22C are diagrams illustrating a nail penetration test.
  • FIG. 23 is a graph showing the temperature rise of the secondary battery when an internal short circuit occurs.
  • FIGS. 24A and 24B are photographs showing the nail penetration test.
  • FIG. 25A is a graph showing changes in battery voltage during the nail penetration test
  • FIG. 25B is a graph showing changes in battery temperature
  • particles is not limited to only spherical shapes (circular cross-sectional shapes), but also includes individual particles whose cross-sectional shapes are elliptical, rectangular, trapezoidal, pyramidal, square with rounded corners, and asymmetrical. Further, individual particles may have an amorphous shape.
  • homogeneity refers to a state in which a certain element (for example, A) is distributed with similar characteristics in a specific region in a solid composed of multiple elements (for example, A, B, and C). Note that it is sufficient that the concentrations of the elements in the specific regions are substantially the same. For example, it is sufficient if the difference in the detected amount of a certain element (for example, the count number in STEM-EDX) between specific regions is within 10%.
  • Specific areas include, for example, the surface layer, the surface, protrusions, recesses, and the inside.
  • a positive electrode active material to which additive elements are added may be expressed as a composite oxide, a positive electrode material, a positive electrode material, a positive electrode material for secondary batteries, etc.
  • the positive electrode active material of one embodiment of the present invention preferably contains a compound.
  • the positive electrode active material of one embodiment of the present invention preferably has a composition.
  • the positive electrode active material of one embodiment of the present invention preferably has a composite.
  • all particles do not necessarily have to have the characteristics. For example, if 50% or more, preferably 70% or more, more preferably 90% or more of three or more randomly selected positive electrode active material particles have the characteristic, it is sufficient to have the positive electrode active material and the same. It can be said that this has the effect of improving the characteristics of the secondary battery.
  • a short circuit in the secondary battery not only causes problems in the charging and/or discharging operation of the secondary battery, but also may cause heat generation and ignition.
  • short current is suppressed even at high charging voltage. Therefore, it is possible to obtain a secondary battery that has both high discharge capacity and safety.
  • materials included in the secondary battery will be described in terms of their state before deterioration.
  • a decrease in discharge capacity due to aging treatment (which may also be called burn-in treatment) in the secondary battery manufacturing stage is not called deterioration.
  • a lithium ion secondary cell or a lithium secondary assembled battery hereinafter referred to as a lithium ion secondary battery
  • the rated capacity is based on JIS C 8711:2019 for lithium ion secondary batteries for portable devices. In the case of other lithium ion secondary batteries, they comply with not only the JIS standards mentioned above but also JIS and IEC standards for electric vehicle propulsion, industrial use, etc.
  • the state of the materials of the secondary battery before deterioration is called the initial product or initial state
  • the state after deterioration (the state when the secondary battery has a discharge capacity of less than 97% of its rated capacity) is called the initial product or initial state.
  • ignition in the nail penetration test means that flame is observed outside the exterior body within one minute after the nail penetration test. Or, it means that thermal runaway of the secondary battery has occurred. For example, if the temperature rise of the secondary battery exceeds 100°C, it can be said that thermal runaway has occurred. The temperature at this time can be measured by a temperature sensor attached to the outer casing of the secondary battery. Furthermore, if a solid thermal decomposition product derived from the positive electrode and/or negative electrode is observed at a location 2 cm or more away from the nail penetration test after the nail penetration test, it can also be said that a fire has occurred.
  • the O/M ratio (M is the sum of nickel, cobalt, and manganese) is theoretically 2.
  • oxygen is released from LiMO 2 due to thermal runaway, the O/M ratio decreases. Therefore, for example, if the O/M ratio in EDX analysis is less than 1.3 at a location 2 cm or more away from the nail penetration test after the nail penetration test, it can be said that thermal runaway has occurred, that is, ignition has occurred.
  • the thermal decomposition products of the positive electrode and/or negative electrode also include, for example, aluminum oxide, which is the oxidation of aluminum in the positive electrode current collector, and copper oxide, which is the oxidation of the copper in the negative electrode current collector.
  • the positive electrode active material 101 includes lithium, a transition metal M, and oxygen.
  • the transition metal M is one or more selected from nickel, manganese, and cobalt, and other elements are not applicable.
  • an additive element for example, one or more selected from fluorine, aluminum, magnesium, titanium, calcium, and zirconium can be used.
  • the positive electrode active material 101 may include nickel-manganese-lithium cobalt oxide to which additional elements are added.
  • the positive electrode active material of a lithium ion secondary battery must contain a transition metal capable of redox in order to maintain charge neutrality even when lithium ions are inserted or removed.
  • the positive electrode active material 101 according to one embodiment of the present invention includes nickel, manganese, and cobalt as the transition metal M responsible for the redox reaction.
  • FIG. 3A is a schematic diagram showing an example of the appearance of the positive electrode active material 101.
  • the positive electrode active material 101 has a plurality of primary particles 100 aggregated to form one secondary particle.
  • the term "primary particle" refers to a particle that is recognized as a single particle during SEM observation.
  • secondary particles refer to aggregates of primary particles.
  • the bonding force acting between a plurality of primary particles does not matter. It may be a covalent bond, an ionic bond, a hydrophobic interaction, a van der Waals force, or any other intermolecular interaction, or a plurality of bonding forces may be at work. Note that in FIG. 3A, the layer 100m containing a large amount of additive elements is not shown for clarity.
  • FIG. 3B shows an example of a schematic cross-sectional view of the positive electrode active material 101.
  • FIG. 3B shows several variations in the case where a layer containing a large amount of additive elements is provided on the primary particles constituting the secondary particles. Some primary particles and their surface layer portions drawn out by arrows are shown in multiple locations in FIG. 3B.
  • the primary particles 100 a region other than the layer containing a large amount of additive elements is referred to as the inside. In other words, the inside is a region where the detected amount of the added element is relatively small.
  • the layer 100m containing a large amount of additive elements is provided on the entire surface of the primary particles 100, and there are also cases where the primary particles 100 are not provided with a layer containing a large amount of additive elements. Further, layers 100m1 and 100m2 containing a large amount of additive elements may be provided at both ends of the primary particles 100, respectively. Further, even in the case of the primary particle 100 disposed in the central part of the secondary particle, the layer 100m containing a large amount of additive elements may be provided on the entire surface of the primary particle 100. Further, a layer 100 m3 containing a large amount of additive elements may be provided only on a part of the surface. Further, a layer 100m4 containing a large amount of additive elements common to the two primary particles may be provided. The thickness of the layer 100m containing a large amount of additive elements is preferably 1 nm or more and 10 nm or less.
  • FIG. 4A shows an example of a schematic cross-sectional view of the positive electrode active material 101a.
  • FIG. 4A shows an example in which a layer 100m5 containing a large amount of additive elements is provided so as to cover the entire outside of the positive electrode active material 101a.
  • FIG. 4B also shows an example of a schematic cross-sectional view of the positive electrode active material 101b.
  • FIG. 4B shows an example in which a layer 100m6 containing a large amount of additive elements is provided on the surface layer of the positive electrode active material 101b.
  • FIG. 4B it can be said that the surface layer portion of the positive electrode active material 101b and the layer 100m6 containing a large amount of additive elements coincide with each other.
  • the positive electrode active material 101 shown in FIG. 3B and FIG. It is possible to obtain the configuration of either the positive electrode active material 101a in FIG. 4A or the positive electrode active material 101b in FIG. 4B, or a configuration similar thereto.
  • the surface layer of at least one of the plurality of primary particles contains a layer containing a large amount of additive elements, cracks that occur between the primary particles during charging and discharging can be reduced, and the secondary battery can improve the safety or longevity characteristics of
  • the positive electrode active material 101 which is a secondary particle, has been described in FIGS. 3 and 4, one embodiment of the present invention is not limited thereto.
  • the positive electrode active material 101 may be a single particle (also referred to as a primary particle) as shown in FIG. 5A. In this case, although it may have grain boundaries 105 inside as shown in FIG. 5B, it is preferable to have high crystallinity, and more preferably to be a single crystal.
  • the layer 100m containing a large amount of the additive element and the inside thereof have the same main component (for example, nickel), and the layer 100m containing a large amount of the additive element and the inside thereof are connected to each other.
  • the layer 100m containing a large amount of additive elements protects the inside, it has an excellent effect against internal short circuits when used in a secondary battery.
  • the structure since the structure has 100 m of layers containing a large amount of additive elements when a nail or the like is penetrated from the outside of the secondary battery, it can be regarded as a positive electrode active material structure that does not ignite or is difficult to ignite.
  • the detected amount of one selected from the additive elements is greater than that inside, so that excessive reaction between the positive electrode active material 101 and the electrolyte can be suppressed. . Therefore, when used in a secondary battery, it can be expected to improve safety against internal short circuits of the secondary battery. Furthermore, corrosion resistance against hydrofluoric acid can be effectively improved.
  • the detected amount of one or more selected from the additive elements in the layer 100m containing a large amount of additive elements becomes higher than that inside the layer 100m, thereby changing the conductivity of the surface of the positive electrode active material 101.
  • the powder resistance of the positive electrode active material 101 is increased.
  • a highly safe secondary battery can be obtained when used in a secondary battery. For example, ignition due to internal short circuits can be suppressed.
  • the amount of the added element detected is larger in the layer 100m containing more added elements than in the inside.
  • the additive element be contained inside at a low concentration.
  • the crystal structure of the positive electrode active material 101 may be made more stable.
  • the concentration of the added element even if it exists inside, it may be below the detection limit in analysis such as EDX and XPS.
  • FIGS. 1A and 1B show models of lithium cobalt oxide containing magnesium and lithium cobalt oxide containing magnesium and fluorine, as examples of positive electrode active materials having 100 m of layers containing many additive elements. For these two models, the energy change upon reaction with metallic lithium was calculated.
  • FIG. 1A there is no fluorine on the surface, and when oxygen is desorbed from lithium cobalt oxide, the oxygen reacts with metal Li originating from the negative electrode (assuming a Li dendrite extending from the negative electrode), forming Li 2 O (lithium oxide). ) is generated.
  • FIG. 1B is a model assuming a case where fluorine is present on the surface and LiF (lithium fluoride) is generated by the reaction between the metal Li derived from the negative electrode and the fluorine.
  • metal Li generates less heat when it reacts with fluorine than with oxygen, so by creating a 100m layer containing a large amount of fluorine-containing additive elements, it can be used in secondary batteries with high safety. There is a possibility that it can be used as a secondary battery.
  • FIG. 2A where only aluminum fluoride is assumed as the additive element source, there is a region with little bonding, as shown by the broken ellipse line in the figure, and it was predicted that the adhesion between the interior and the surface layer would be poor.
  • FIGS. 2B to 2D which assume that both aluminum fluoride and lithium fluoride are used as additive element sources, the regions with few bonds as in FIG. 2A are reduced, and the crystal structure is oriented in at least a portion It was predicted that the adhesion between the inside and the surface layer was relatively good.
  • the positive electrode active material 101 of one embodiment of the present invention preferably has a layered rock salt crystal structure.
  • it is preferable that x, y, and z satisfy x:y:z 1:4:1 or a value in the vicinity thereof.
  • a value in the vicinity of a composition refers to a range in which the composition is obtained when the significant figure is set to one digit. At this time, the digits below the significant figures are rounded off.
  • a positive electrode active material having a layered rock salt type crystal structure and containing nickel, cobalt, and manganese as transition metals M is also referred to as NCM.
  • the positive electrode active material 101 according to one embodiment of the present invention is a single particle (primary particle), it is preferable that the particle size is smaller so that cracks are less likely to occur. On the other hand, if the particle size is too small, there is a concern that the specific surface area will increase and side reactions with the electrolyte will increase. Therefore, the positive electrode active material of one embodiment of the present invention preferably has a median diameter of 2 ⁇ m or more and 20 ⁇ m or less as measured by a laser diffraction/scattering method.
  • the surface of the positive electrode active material is preferably smooth and glossy.
  • the positive electrode active material has no corners or is rounded. Due to its smooth surface and lack of corners, the specific surface area is small and cracks are less likely to occur.
  • ultrafine particles may be fragments of the positive electrode active material and/or sources of additive elements that have not reacted.
  • ultrafine particles refer to metal compound particles having a particle size of 0.001 ⁇ m or more and 1 ⁇ m or less.
  • the particle size of the ultrafine particles is the Feret diameter or projection circle equivalent diameter measured from a surface SEM image. Whether it is a metal compound or not can be analyzed by SEM-EDX or the like.
  • the positive electrode active material of one embodiment of the present invention a material that functions as a flux is added together with the additive element source.
  • the surface of the composite oxide and the additive element source are melted during heating, and then solidified. Therefore, even if extremely small particles are attached to the surface, they will be melted together in these steps and will not remain on the surface or will be extremely small.
  • the fact that there are no or very few ultrafine particles on the surface of the positive electrode active material can also be said to indicate that the composite oxide and the material functioning as a flux were heated together in the manufacturing process.
  • the above analysis method is particularly effective when the particle size is 1 ⁇ m or more because of the resolution of the surface SEM image.
  • the positive electrode active material 101 having a relatively small particle size is expected to have high charge/discharge rate characteristics.
  • the positive electrode active material 101 having a relatively large particle size is expected to have high charge/discharge cycle characteristics and maintain a high discharge capacity.
  • transition metal M sources that is, a nickel source (Ni source), a cobalt source (Co source), and a manganese source (Mn source) are first prepared. It is preferable that the mixing ratio of nickel, cobalt, and manganese be such that a layered rock salt type crystal structure can be formed.
  • the raw material may be cheaper than when the positive electrode active material 101 contains a large amount of cobalt, and the charge/discharge capacity per weight may increase, which is preferable.
  • nickel in the transition metal M (M is the sum of nickel, cobalt, and manganese), nickel preferably exceeds 25 atom %, more preferably 60 atom % or more, and even more preferably 80 atom % or more.
  • the content of nickel in the transition metal M is 95 atomic % or less.
  • cobalt as the transition metal M, since the average discharge voltage is high and cobalt contributes to stabilizing the layered rock-salt structure, resulting in a highly reliable secondary battery.
  • the transition metal M it is preferable to have manganese as the transition metal M because heat resistance and chemical stability are improved. 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 the content of manganese in the transition metal M is 2.5 atomic % or more and 34 atomic % or less.
  • the transition metal M source is prepared as an aqueous solution containing transition metal M.
  • an aqueous solution of nickel salt can be used.
  • nickel salt for example, nickel sulfate, nickel chloride, nickel nitrate, or hydrates thereof can be used.
  • organic acid salts of nickel such as nickel acetate, or hydrates thereof can also be used.
  • an aqueous solution of nickel alkoxide or an organic nickel complex can be used as the nickel source.
  • an organic acid salt refers to a compound of an organic acid such as acetic acid, citric acid, oxalic acid, formic acid, butyric acid, and a metal.
  • an aqueous solution of cobalt salt can be used as the cobalt source.
  • cobalt salt for example, cobalt sulfate, cobalt chloride, cobalt nitrate, or hydrates thereof can be used.
  • organic acid salts of cobalt such as cobalt acetate, or hydrates thereof can also be used.
  • an aqueous solution of a cobalt alkoxide or an organic cobalt complex can be used as the cobalt source.
  • an aqueous solution of manganese salt can be used as the manganese source.
  • the manganese salt for example, manganese sulfate, manganese chloride, manganese nitrate, or an aqueous solution of a hydrate thereof can be used.
  • organic acid salts of manganese such as manganese acetate, or hydrates thereof can also be used.
  • an aqueous solution of manganese alkoxide or an organic manganese complex can be used as the manganese source.
  • an aqueous solution in which nickel sulfate, cobalt sulfate, and manganese sulfate are dissolved in pure water is prepared as a transition metal M source.
  • the aqueous solution exhibits acidity.
  • a chelating agent may be prepared.
  • Chelating agents include, for example, glycine, oxine, 1-nitroso-2-naphthol, 2-mercaptobenzothiazole, or EDTA (ethylenediaminetetraacetic acid).
  • you may use multiple types selected from glycine, oxine, 1-nitroso-2-naphthol, and 2-mercaptobenzothiazole. At least one of these is dissolved in pure water and used as a chelate aqueous solution.
  • Chelating agents are complexing agents that create chelate compounds and are preferred over common complexing agents.
  • a complexing agent may be used instead of a chelating agent, and aqueous ammonia can be used as the complexing agent.
  • a chelate aqueous solution because it can suppress unnecessary generation of crystal nuclei and promote growth. When the generation of unnecessary nuclei is suppressed, the generation of fine particles is suppressed, so that a composite hydroxide with a good particle size distribution can be obtained.
  • an aqueous chelate solution the acid-base reaction can be delayed, and the reaction proceeds gradually, making it possible to obtain nearly spherical secondary particles.
  • Glycine has the effect of keeping the pH value constant at a pH of 9 or more and 10 or less, and by using a glycine aqueous solution as the chelate aqueous solution, the pH of the reaction tank when obtaining the above composite hydroxide 98 can be adjusted. This is preferable because it is easier to control.
  • Step S114 Next, in step S114 in FIG. 6A, a transition metal M source and a chelating agent are mixed to prepare an acid solution.
  • an alkaline solution is prepared.
  • an aqueous solution containing sodium hydroxide, potassium hydroxide, lithium hydroxide or ammonia can be used.
  • An aqueous solution in which these are dissolved using pure water can be used.
  • it may be an aqueous solution in which multiple types selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, or ammonia are dissolved in pure water.
  • the pure water preferably used for the transition metal M source and alkaline solution is water with a specific resistance of 1 M ⁇ cm or more, more preferably water with a specific resistance of 10 M ⁇ cm or more, and even more preferably 15 M ⁇ cm or more. water. Water that satisfies the specific resistance has high purity and contains very few impurities.
  • Step S122 it is preferable to prepare water in the reaction tank.
  • This water may be an aqueous solution of a chelating agent, but is more preferably pure water. By using pure water, nucleation is promoted and a composite hydroxide with a small particle size can be produced.
  • the water prepared in this reaction tank can be called a filling liquid or adjustment liquid for the reaction tank.
  • a chelate aqueous solution the description of step S13 can be referred to.
  • step S131 of FIG. 6A the acid solution and the alkaline solution are mixed and reacted.
  • the reaction can be referred to as a coprecipitation reaction, a neutralization reaction, or an acid-base reaction.
  • the pH of the reaction system is 9.0 or more and 11.5 or less.
  • the pH of the aqueous solution in the reaction tank when an alkaline solution is placed in a reaction tank and an acid solution is dropped into the reaction tank, it is preferable to maintain the pH of the aqueous solution in the reaction tank within the range of the above conditions.
  • an acid solution is placed in a reaction tank and an alkaline solution is added dropwise.
  • the amount of solution in the reaction tank is 200 mL or more and 350 mL or less
  • the dropping rate of the acid solution or alkaline solution is preferably 0.01 mL/min or less because pH conditions can be easily controlled.
  • the reaction tank has a reaction container and the like.
  • stirring means include stirring by rotation of a stirrer or stirring blades. Two or more stirring blades and six or less stirring blades can be provided. For example, when four stirring blades are provided, they are preferably arranged in a cross shape when viewed from above.
  • the rotation speed of the stirring means is preferably 800 rpm or more and 1200 rpm or less.
  • a baffle plate may be provided in the reaction tank to change the stirring direction and flow rate. By providing a baffle plate, mixing efficiency is improved and more uniform composite hydroxide particles can be synthesized.
  • the temperature of the reaction tank is preferably adjusted to 50°C or more and 90°C or less. It is preferable to start dropping the alkaline solution or acid solution after the reaction tank has reached the desired temperature.
  • the inert atmosphere in this case can be nitrogen or argon.
  • nitrogen gas is preferably introduced at a flow rate of 0.5 L/min or more and 2 L/min or less.
  • a reflux condenser allows nitrogen gas to be vented from the reactor and water vapor to be returned to the reactor.
  • Step S132> In order to recover the composite hydroxide 98, it is preferable to perform filtration as shown in step S132 of FIG. 6A.
  • the filtration is preferably suction filtration.
  • an organic solvent such as acetone
  • the filtered composite hydroxide 98 is preferably dried. For example, it is dried under vacuum at a temperature of 60° C. or more and 200° C. or less for 0.5 hours or more and 20 hours or less. For example, it can be dried for 12 hours. In this way, composite hydroxide 98 can be obtained.
  • composite hydroxide 98 containing transition metal M can be obtained.
  • the composite hydroxide 98 refers to hydroxides of multiple types of metals.
  • the composite hydroxide 98 can be said to be a precursor of the positive electrode active material 101.
  • Step S141 Next, in step S141 of FIG. 6B, a lithium source and an additive element source are prepared.
  • lithium when the sum of nickel, cobalt, and manganese atoms is 1, it is more preferable that lithium be around 1.0 (atomic ratio).
  • lithium hydroxide lithium carbonate, lithium fluoride, or lithium nitrate
  • a material with a low melting point among lithium compounds such as lithium hydroxide (melting point: 462°C). Since cation mixing occurs more easily in a positive electrode active material containing a high proportion of nickel than in lithium cobalt oxide, etc., it is necessary to perform heating in step S143 and the like at a low temperature. Therefore, it is preferable to use a material with a low melting point.
  • the particle size of the lithium source is small because the reaction tends to proceed well.
  • a lithium source made into fine particles using a fluidized bed jet mill can be used.
  • the particle size here is the average particle size (also called average particle size) of the particle size distribution.
  • additive element source a compound having one or more selected from fluorine, aluminum, magnesium, titanium, calcium, and zirconium can be used.
  • fluorine sources include lithium fluoride (LiF), magnesium fluoride (MgF 2 ), aluminum fluoride (AlF 3 ), titanium fluoride (TiF 4 ), cobalt fluoride (CoF 2 , CoF 3 ), and nickel fluoride ( NiF 2 ), zirconium fluoride (ZrF 4 ), vanadium fluoride (VF 5 ), manganese fluoride, iron fluoride, chromium fluoride, niobium fluoride, zinc fluoride (ZnF 2 ), calcium fluoride (CaF 2 ) ), sodium fluoride (NaF), potassium fluoride (KF), barium fluoride (BaF 2 ), cerium fluoride (CeF 3 , CeF 4 ), lanthanum fluoride (LaF 3 ), or sodium aluminum hexafluoride ( Na 3 AlF 6 ), etc. can be used.
  • lithium fluoride is preferable because it has a relatively
  • the fluorine source may be a gas, such as fluorine (F 2 ), fluorocarbon, sulfur fluoride, or fluorinated oxygen (OF 2 , O 2 F 2 , O 3 F 2 , O 4 F 2 , O 5 F 2 , O 6 F 2 , O 2 F) or the like may be used and mixed in the atmosphere in the heating step described later. Further, a plurality of the above-mentioned fluorine sources may be used.
  • aluminum compounds such as aluminum oxide, aluminum hydroxide, and aluminum fluoride, and/or metal aluminum can be used.
  • magnesium sources for example, magnesium compounds such as magnesium fluoride, magnesium oxide, magnesium hydroxide, or magnesium carbonate, and/or magnesium metal can be used. Further, a plurality of the above-mentioned magnesium sources may be used.
  • Magnesium fluoride can be used both as a fluorine source and as a magnesium source. Lithium fluoride can also be used as a lithium source.
  • titanium compounds such as titanium oxide, titanium hydroxide, and titanium fluoride, and/or titanium metal can be used.
  • calcium compounds such as calcium carbonate, calcium fluoride, calcium hydroxide, and calcium oxide, and/or metallic calcium can be used.
  • zirconium compounds such as zirconium oxide, zirconium hydroxide, and zirconium fluoride, and/or metal zirconium can be used.
  • lithium fluoride can function as a flux in the subsequent heating step.
  • a phase diagram of magnesium fluoride, which is a fluorine source and a magnesium source, and lithium fluoride, which is a fluxing agent is shown in FIG. 8 (cited and added from FIG. 7 of Non-Patent Document 1).
  • the eutectic point P of LiF and MgF 2 is around 742° C. (T1).
  • FIG. 9 a phase diagram of nickel fluoride, which is a fluorine source and a nickel source, and lithium fluoride, which is a flux, is shown in FIG. 9 (cited from Non-Patent Document 2, FIG. 3).
  • the eutectic point of LiF and NiF 2 is within the range of 1060 [K] to 1065 [K] (787°C to within the range of 792°C).
  • the eutectic point of aluminum fluoride which is a fluorine source and an aluminum source
  • lithium fluoride which is a flux
  • lithium fluoride which can function as a flux
  • an additive element source such as aluminum fluoride
  • they can be melted together with part of the surface layer of the composite oxide in the subsequent heating process. , forming a molten layer.
  • the molten layer is cooled after the heating step, it becomes a thin and dense barrier film, such as a film formed by an ALD (Atomic Layer Deposition) method.
  • the additive elements are dissolved in solid solution with good concentration and distribution of the additive elements, resulting in a barrier film in which the crystal orientation roughly matches that of the inside.
  • step S142 in FIG. 6B the composite hydroxide 98 and a lithium source are mixed.
  • Mixing can be done dry or wet.
  • a ball mill, a bead mill, etc. can be used for mixing.
  • zirconia balls it is preferable to use zirconia balls as the media, for example.
  • the peripheral speed is preferably 100 mm/sec to 2000 mm/sec in order to suppress contamination from media or materials.
  • the cobalt compound and the lithium compound may be crushed.
  • Step S143 Next, the mixture of the composite hydroxide 98 and the lithium source is heated. To distinguish from other heating steps, in FIGS. 6B and 7, step S143 may be referred to as first heating, step S145 as second heating, and step S153 as third heating.
  • An electric furnace or a rotary kiln can be used as a firing device for performing this heating.
  • the crucible, sheath, setter, and container used during heating are preferably made of materials that do not easily release impurities.
  • an aluminum oxide crucible with a purity of 99.9% may be used.
  • mullite/cordierite (Al 2 O 3 .SiO 2 .MgO) pods may be used.
  • the temperature of the heating in step S143 is preferably 400°C or more and 750°C or less, more preferably 650°C or more and 750°C or less. Further, the heating time in step S143 is preferably 1 hour or more and 30 hours or less, more preferably 2 hours or more and 20 hours or less.
  • the heating atmosphere is preferably an oxygen-containing atmosphere or an oxygen-containing atmosphere that is so-called dry air and contains little water (for example, a dew point of -50°C or lower, more preferably a dew point of -80°C or lower).
  • step S144 it is preferable to include a crushing step after heating as step S144. Disintegration can be carried out, for example, in a mortar. Furthermore, it may be classified using a sieve.
  • step S145 heating is performed. It is preferable that the heating temperature in step S145 is higher than the heating temperature in step S143.
  • the heating in step S143 may be referred to as preliminary firing, and the heating in step S145 may be referred to as main firing.
  • the temperature of the heating in step S145 is preferably higher than 750°C and lower than 1050°C. Further, the heating time in step S145 is preferably 1 hour or more and 30 hours or less, more preferably 2 hours or more and 20 hours or less.
  • step S146 it is preferable to include a crushing step after heating as step S146. Disintegration can be carried out, for example, in a mortar. Furthermore, it may be classified using a sieve. Through the above steps, a positive electrode active material 101 is obtained.
  • FIGS. 6A and 6B describe a manufacturing method in which the step of adding an additive element source is performed once, one embodiment of the present invention is not limited to this.
  • the additive element source may be added in multiple portions.
  • a method for producing a positive electrode active material in which an additive element source is added in two steps will be described with reference to FIG. Mainly, points different from the manufacturing method explained with reference to FIGS. 6A and 6B will be explained.
  • Step S111 to Step S133 First, as in FIG. 6A, a composite hydroxide 98 is produced through steps S111 to S133.
  • Step S141 to Step S146> a composite oxide 99 is obtained through steps similar to steps S141 to S146 in FIG. 6B.
  • step S151 in FIG. 7 an additive element source is prepared.
  • the description in step S141 can be referred to.
  • Step S152 Next, the composite oxide 99 and the additive element source are mixed.
  • step S142 the description of step S142 can be referred to.
  • Step S153 Next, the mixture of the composite oxide 99 and the additive element source is heated.
  • the heating in step S153 is preferably at a sufficiently high temperature in order to increase the crystallite size of the positive electrode active material 101, but the temperature range may vary depending on the composition of the transition metal M.
  • the temperature is preferably 750°C or higher.
  • the temperature is preferably 950°C or lower, more preferably 920°C or lower, and even more preferably 900°C or lower.
  • the temperature is preferably 850°C or higher, more preferably 900°C or higher, and even more preferably 1000°C or lower.
  • the heating temperature in step S153 is too high, the same disadvantages as described above may occur, so it is preferably 1050° C. or lower. For other heating conditions, refer to the description of step S143.
  • step S154 it is preferable to include a crushing step after heating as step S154.
  • the description of step S144 can be referred to.
  • FIG. 7 describes a method of heating in step S153 after mixing the additive element source in step S151, one embodiment of the present invention is not limited to this. Heating may be performed two or more times as the heating in step S153.
  • the positive electrode active material 101 can be produced.
  • additive elements may be added together with the transition metal M source.
  • the additive element may be added after the composite oxide containing lithium and the transition metal M is produced.
  • additional elements may be added to the composite oxide containing lithium and transition metal M that has been prepared in advance. By changing the process of adding the additive element, it may be possible to change the depth profile of the additive element in the positive electrode active material.
  • FIG. 11A is an exploded perspective view of a coin-shaped (single-layer flat type) secondary battery
  • FIG. 11B is an external view
  • FIG. 11C is a cross-sectional view thereof.
  • Coin-shaped secondary batteries are mainly used in small electronic devices.
  • FIG. 11A is a schematic diagram so that the overlapping (vertical relationship and positional relationship) of members can be seen. Therefore, FIG. 11A and FIG. 11B are not completely corresponding diagrams.
  • the positive electrode 304, separator 310, negative electrode 307, spacer 322, and washer 312 are stacked. These are sealed with a negative electrode can 302 and a positive electrode can 301 with a gasket. Note that in FIG. 11A, a gasket for sealing is not shown.
  • the spacer 322 and the washer 312 are used to protect the inside or fix the position inside the can when the positive electrode can 301 and the negative electrode can 302 are crimped together.
  • the spacer 322 and washer 312 are made of stainless steel or an insulating material.
  • a positive electrode 304 has a laminated structure in which a positive electrode active material layer 306 is formed on a positive electrode current collector 305 .
  • a slurry containing the positive electrode active material 101 is applied onto the current collector and dried to form the positive electrode active material layer 306. Pressing may be performed after forming the positive electrode active material layer 306.
  • the slurry includes a conductive material, a binder, and a solvent in addition to the positive electrode active material 101. Note that a carbon material such as graphite or carbon fiber is used as the conductive material.
  • a carbon material or a metal material is typically used as the conductive material.
  • the conductive material is in the form of particles, and examples of the conductive material in the form of particles include carbon black (furnace black, acetylene black, graphite, etc.). Carbon black often has a smaller particle size than the positive electrode active material.
  • the conductive material may be in the form of fibers, and carbon nanotubes (CNTs) and VGCF (registered trademark) are examples of the conductive aids in the form of fibers.
  • CNTs carbon nanotubes
  • VGCF registered trademark
  • sheet-like conductive materials such as multilayer graphene as a sheet-like conductive aid.
  • the sheet-like conductive additive may appear thread-like in the cross section of the positive electrode.
  • Particulate conductive materials can get into gaps in the positive electrode active material, etc., and are likely to aggregate. Therefore, the particulate conductive material can assist in forming a conductive path between the cathode active materials disposed nearby.
  • the fibrous conductive material also has a bent region, but it is larger than the positive electrode active material. Therefore, the fibrous conductive material can assist the conductive path not only between adjacent positive electrode active materials but also between distant positive electrode active materials. In this way, it is preferable to mix two or more shapes of conductive aids.
  • the weight of carbon black is 1.5 times or more and 20 times or less of the multilayer graphene. , preferably 2 times or more and 9.5 times or less in weight.
  • graphene includes multilayer graphene and multigraphene.
  • graphene refers to something that contains carbon, has a shape such as a flat plate or a sheet, and has a two-dimensional structure formed of a six-membered carbon ring.
  • the two-dimensional structure formed by the six-membered carbon ring is sometimes called a carbon sheet.
  • graphene compounds include graphene oxide, multilayer graphene oxide, multilayer graphene oxide, reduced graphene oxide, reduced multilayer graphene oxide, reduced multilayer graphene oxide, graphene quantum dots, and the like.
  • the graphene compound may have a functional group.
  • it is preferable that the graphene or graphene compound has a bent shape.
  • graphene or a graphene compound may be rounded, and rounded graphene is sometimes called carbon nanofiber.
  • graphene oxide refers to one that contains carbon and oxygen, has a sheet-like shape, and has a functional group, particularly an epoxy group, a carboxy group, or a hydroxy group.
  • Fluorine-containing graphene may be used as the graphene compound. Fluorine in the graphene compound is preferably adsorbed on the surface. Further, fluorine-containing graphene can be produced by bringing graphene and a fluorine compound into contact (referred to as fluorination treatment). Fluorine (F 2 ) or a fluorine compound may be used for the fluorination treatment. Examples of fluorine compounds include hydrogen fluoride, fluorinated halogens ( ClF3 , IF5, etc.), gaseous fluorides ( BF3 , NF3 , PF5 , SiF4 , SF6 , etc.), metal fluorides (LiF, NiF2, etc. ).
  • the fluorination treatment it is preferable to use a gaseous fluoride, and the gaseous fluoride may be diluted with an inert gas.
  • the temperature of the fluorination treatment is preferably room temperature, and is preferably 0° C. or higher and 250° C. or lower, which includes the room temperature. When the fluorination treatment is performed at 0° C. or higher, fluorine can be adsorbed onto the surface of graphene.
  • Graphene compounds may have excellent electrical properties such as high conductivity, and excellent physical properties such as high flexibility and high mechanical strength. Further, the graphene compound has a sheet-like shape. Graphene compounds may have curved surfaces, allowing surface contact with low contact resistance. Further, even if it is thin, it may have very high conductivity, and a conductive path can be efficiently formed within the active material layer with a small amount. Therefore, by using a graphene compound as a conductive material, the contact area between the active material and the conductive material can be increased.
  • the graphene compound preferably covers 80% or more of the area of the active material. Note that it is preferable that the graphene compound clings to at least a portion of the active material particles.
  • the graphene compound overlaps at least a portion of the active material particles. Further, it is preferable that the shape of the graphene compound matches at least a portion of the shape of the active material particles.
  • the shape of the active material particles refers to, for example, the unevenness of a single active material particle or the unevenness formed by a plurality of active material particles. Further, it is preferable that the graphene compound surrounds at least a portion of the active material particles. Further, the graphene compound may have holes.
  • active material particles with a small particle size for example, active material particles of 1 ⁇ m or less
  • the specific surface area of the active material particles is large, and more conductive paths connecting the active material particles are required.
  • Rapid charging and discharging refers to charging and discharging at a rate of, for example, 200 mA/g, 400 mA/g, or 1000 mA/g or more.
  • Fluorine-containing acetylene black may be used as the conductive material.
  • the fluorine present in the fluorine-containing acetylene black is preferably adsorbed on the surface.
  • fluorine-containing acetylene black can be produced by bringing acetylene black into contact with a fluorine compound (referred to as fluorination treatment).
  • fluorination treatment the content explained for graphene can be applied to acetylene black.
  • fluorine present in the fluorine-containing carbon nanotubes as a conductive material is preferably adsorbed on the surface.
  • fluorine-containing carbon nanotubes can be produced by bringing carbon nanotubes into contact with a fluorine compound (referred to as fluorination treatment).
  • fluorination treatment the content explained for graphene can be applied to carbon nanotubes.
  • binder it is preferable to use rubber materials such as styrene-butadiene rubber (SBR), styrene-isoprene-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, and ethylene-propylene-diene copolymer. Furthermore, fluororubber can be used as the binder.
  • SBR styrene-butadiene rubber
  • fluororubber can be used as the binder.
  • the binder it is preferable to use, for example, a water-soluble polymer.
  • a water-soluble polymer for example, polysaccharides can be used.
  • the polysaccharide one or more of cellulose derivatives such as carboxymethyl cellulose (CMC), methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, regenerated cellulose, starch, etc. can be used. Further, it is more preferable to use these water-soluble polymers in combination with the above-mentioned rubber material.
  • CMC carboxymethyl cellulose
  • ethyl cellulose methyl cellulose
  • hydroxypropyl cellulose diacetyl cellulose
  • regenerated cellulose starch, etc.
  • polystyrene polymethyl acrylate, polymethyl methacrylate (polymethyl methacrylate, PMMA), sodium polyacrylate, polyvinyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide, polyimide, polyvinyl chloride
  • PVA polyvinyl alcohol
  • PEO polyethylene oxide
  • PEO polypropylene oxide
  • polyimide polyvinyl chloride
  • materials such as polytetrafluoroethylene, polyethylene, polypropylene, polyisobutylene, polyethylene terephthalate, nylon, polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), ethylene propylene diene polymer, polyvinyl acetate, nitrocellulose, etc.
  • the binder may be used in combination of more than one of the above.
  • FIG. 11B is a perspective view of the completed coin-shaped secondary battery.
  • a positive electrode can 301 that also serves as a positive electrode terminal and a negative electrode can 302 that also serves as a negative electrode terminal are insulated and sealed with a gasket 303 made of polypropylene or the like.
  • the positive electrode 304 is formed by a positive electrode current collector 305 and a positive electrode active material layer 306 provided in contact with the positive electrode current collector 305 .
  • the negative electrode 307 is formed of a negative electrode current collector 308 and a negative electrode active material layer 309 provided in contact with the negative electrode current collector 308. Further, the negative electrode 307 is not limited to a laminated structure, and lithium metal foil or lithium-aluminum alloy foil may be used.
  • each of the positive electrode 304 and negative electrode 307 used in the coin-shaped secondary battery 300 may be formed only on one side.
  • the positive electrode can 301 and the negative electrode can 302 metals such as nickel, aluminum, titanium, etc., which are corrosion resistant to electrolyte, or alloys thereof, or alloys of these and other metals (for example, stainless steel, etc.) can be used. can. Further, in order to prevent corrosion due to electrolyte and the like, it is preferable to coat with nickel, aluminum, or the like.
  • the positive electrode can 301 is electrically connected to the positive electrode 304
  • the negative electrode can 302 is electrically connected to the negative electrode 307.
  • negative electrode 307, positive electrode 304, and separator 310 are immersed in an electrolytic solution, and the positive electrode 304, separator 310, negative electrode 307, and negative electrode can 302 are stacked in this order with the positive electrode can 301 facing down, as shown in FIG. 301 and a negative electrode can 302 are crimped together via a gasket 303 to produce a coin-shaped secondary battery 300.
  • an electrolytic solution including a solvent and an electrolyte dissolved in the solvent can be used.
  • aprotic organic solvents are preferred, such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, chloroethylene carbonate, vinylene carbonate, ⁇ -butyrolactone, ⁇ -valerolactone, and dimethyl carbonate.
  • DMC diethyl carbonate
  • DEC diethyl carbonate
  • EMC ethyl methyl carbonate
  • methyl formate methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, 1,3-dioxane, 1,4 -
  • DME dimethoxyethane
  • DME dimethyl sulfoxide
  • diethyl ether methyl diglyme
  • acetonitrile benzonitrile
  • tetrahydrofuran sulfolane
  • sultone etc.
  • Ionic liquids are composed of cations and anions, and include organic cations and anions.
  • Examples of the organic cation used in the electrolytic solution 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 anions used in the electrolytic solution include monovalent amide anions, monovalent methide anions, fluorosulfonic acid anions, perfluoroalkylsulfonic acid anions, tetrafluoroborate anions, perfluoroalkylborate anions, and hexafluorophosphate anions. , or perfluoroalkyl phosphate anion.
  • electrolytes to be dissolved in the above solvent examples include LiPF 6 , LiClO 4 , LiAsF 6 , LiBF 4 , LiAlCl 4 , LiSCN, LiBr, LiI, Li 2 SO 4 , Li 2 B 10 Cl 10 , Li 2 B 12 Cl12 , LiCF3SO3 , LiC4F9SO3 , LiC (CF3SO2 ) 3 , LiC( C2F5SO2 ) 3 , LiN ( CF3SO2 ) 2 , LiN ( C4F9
  • One type of lithium salt such as SO 2 )(CF 3 SO 2 ), LiN(C 2 F 5 SO 2 ) 2 , lithium bis(oxalate)borate (Li(C 2 O 4 ) 2 , LiBOB), or any of these Two or
  • the electrolyte contains vinylene carbonate, propane sultone (PS), tert-butylbenzene (TBB), fluoroethylene carbonate (FEC), lithium bis(oxalate)borate (LiBOB), and dinitrile compounds such as succinonitrile and adiponitrile.
  • Additives such as fluorobenzene and ethylene glycose bis(propionitrile) ether may also be added.
  • the concentration of each additive may be, for example, 0.1 wt% or more and 5 wt% or less with respect to the solvent in which the electrolyte is dissolved.
  • adiponitrile is expected to enhance high voltage resistance through interaction with the surface of the positive electrode active material 101 of one embodiment of the present invention, and therefore adiponitrile cannot be used in a secondary battery using the positive electrode active material of one embodiment of the present invention.
  • the additive may form a film that adheres to the surface of the active material during aging treatment of the secondary battery. Therefore, in a secondary battery that has been charged and discharged even slightly, at least some additives may not be detected in the electrolyte.
  • vinylene carbonate is known to form a film on the surface of the negative electrode active material, so even if it is added at the manufacturing stage, it may not be detected in the electrolyte of commercially available secondary batteries.
  • a separator When the electrolyte contains an electrolytic solution, a separator is placed between the positive electrode and the negative electrode.
  • a separator for example, fibers containing cellulose such as paper, nonwoven fabrics, glass fibers, ceramics, synthetic fibers using nylon (polyamide), vinylon (polyvinyl alcohol fiber), polyester, acrylic, polyolefin, polyurethane, etc. It is possible to use one formed of . It is preferable that the separator is processed into a bag shape and arranged so as to surround either the positive electrode or the negative electrode.
  • the separator may have a multilayer structure.
  • a film of an organic material such as polypropylene or polyethylene can be coated with a ceramic material, a fluorine material, a polyamide material, or a mixture thereof.
  • the ceramic material for example, aluminum oxide particles, silicon oxide particles, etc. can be used.
  • the fluorine-based material for example, PVDF, polytetrafluoroethylene, etc. can be used.
  • the polyamide material for example, nylon, aramid (meta-aramid, para-aramid), etc. can be used.
  • Coating with a ceramic material improves oxidation resistance, so it is possible to suppress deterioration of the separator during high voltage charging and discharging and improve the reliability of the secondary battery. Furthermore, coating with a fluorine-based material makes it easier for the separator and electrode to come into close contact with each other, thereby improving output characteristics. Coating with a polyamide-based material, especially aramid, improves heat resistance, thereby improving the safety of the secondary battery.
  • a mixed material of aluminum oxide and aramid may be coated on both sides of a polypropylene film.
  • the surface of the polypropylene film in contact with the positive electrode may be coated with a mixed material of aluminum oxide and aramid, and the surface in contact with the negative electrode may be coated with a fluorine-based material.
  • the safety of the secondary battery can be maintained even if the overall thickness of the separator is thin, so the capacity per volume of the secondary battery can be increased.
  • the cylindrical secondary battery 616 has a positive electrode cap (battery lid) 601 on the top surface and a battery can (exterior can) 602 on the side and bottom surfaces. These positive electrode cap 601 and battery can (exterior can) 602 are insulated by a gasket (insulating packing) 610.
  • FIG. 12B is a diagram schematically showing a cross section of a cylindrical secondary battery.
  • the cylindrical secondary battery shown in FIG. 12B has a positive electrode cap (battery lid) 601 on the top surface and a battery can (exterior can) 602 on the side and bottom surfaces.
  • These positive electrode caps and the battery can (exterior can) 602 are insulated by a gasket (insulating packing) 610.
  • a band-shaped positive electrode 604 and a negative electrode 606 are wound with a separator 605 in between.
  • a wound body in which a band-shaped positive electrode 604 and a negative electrode 606 are wound with a separator 605 in between is wound around a central axis.
  • the battery can 602 has one end closed and the other end open.
  • metals such as nickel, aluminum, titanium, etc., which are corrosion resistant to electrolyte, or alloys thereof, or alloys of these and other metals (for example, stainless steel, etc.) can be used. .
  • the battery can 602 in order to prevent corrosion caused by the electrolyte, it is preferable to coat the battery can 602 with nickel, aluminum, or the like. Inside the battery can 602, a wound body in which a positive electrode, a negative electrode, and a separator are wound is sandwiched between a pair of opposing insulating plates 608 and 609. Furthermore, a non-aqueous electrolyte (not shown) is injected into the inside of the battery can 602 provided with the wound body. As the non-aqueous electrolyte, the same one as a coin-type secondary battery can be used.
  • 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.
  • Both the positive electrode terminal 603 and the negative electrode terminal 607 can be made of a metal material such as aluminum.
  • the positive terminal 603 and the negative terminal 607 are resistance welded to the safety valve mechanism 613 and the bottom of the battery can 602, respectively.
  • the safety valve mechanism 613 is electrically connected to the positive electrode cap 601 via a PTC element (Positive Temperature Coefficient) 611. The safety valve mechanism 613 disconnects the electrical connection between the positive electrode cap 601 and the positive electrode 604 when the increase in the internal pressure of the battery exceeds a predetermined threshold value.
  • the PTC element 611 is a heat-sensitive resistance element 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.
  • FIG. 12C shows an example of the power storage system 615.
  • Power storage system 615 includes a plurality of secondary batteries 616.
  • the positive electrode of each secondary battery contacts a conductor 624 separated by an insulator 625 and is electrically connected.
  • the conductor 624 is electrically connected to the control circuit 620 via the wiring 623.
  • the negative electrode of each secondary battery is electrically connected to the control circuit 620 via a wiring 626.
  • As the control circuit 620 a charging/discharging control circuit that performs charging and discharging, or a protection circuit that prevents overcharging and/or overdischarging can be applied.
  • FIG. 12D shows an example of the power storage system 615.
  • the power storage system 615 has a plurality of secondary batteries 616, and the plurality of secondary batteries 616 are sandwiched between a conductive plate 628 and a conductive plate 614.
  • the plurality of secondary batteries 616 are electrically connected to a conductive plate 628 and a conductive plate 614 by wiring 627.
  • the plurality of secondary batteries 616 may be connected in parallel, connected in series, or connected in parallel and then further connected in series.
  • the set may be further connected in series.
  • a temperature control device may be provided between the plurality of secondary batteries 616.
  • the secondary battery 616 When the secondary battery 616 is overheated, it can be cooled by the temperature control device, and when the secondary battery 616 is too cold, it can be heated by the temperature control device. Therefore, the performance of power storage system 615 is less affected by outside temperature.
  • the power storage system 615 is electrically connected to the control circuit 620 via wiring 621 and wiring 622.
  • the wiring 621 is electrically connected to the positive electrodes of the plurality of secondary batteries 616 via the conductive plate 628
  • the wiring 622 is electrically connected to the negative electrodes of the plurality of secondary batteries 616 via the conductive plate 614.
  • FIGS. 13 and 14 A structural example of a secondary battery will be described using FIGS. 13 and 14.
  • a secondary battery 913 shown in FIG. 13A has a wound body 950 in which a terminal 951 and a terminal 952 are provided inside a casing 930.
  • the wound body 950 is immersed in the electrolyte inside the housing 930.
  • the terminal 952 is in contact with the housing 930, and the terminal 951 is not in contact with the housing 930 by using an insulating material or the like.
  • the housing 930 is shown separated in FIG. 13A for convenience, in reality, the wound body 950 is covered by the housing 930, and the terminals 951 and 952 extend outside the housing 930.
  • a metal material for example, aluminum
  • a resin material can be used as the housing 930.
  • the casing 930 shown in FIG. 13A may be formed of a plurality of materials.
  • a housing 930a and a housing 930b are bonded together, and a wound body 950 is provided in an area surrounded by the housing 930a and the housing 930b.
  • an insulating material such as organic resin can be used.
  • a material such as an organic resin on the surface where the antenna is formed shielding of the electric field by the secondary battery 913 can be suppressed.
  • an antenna may be provided inside the housing 930a.
  • a metal material can be used as the housing 930b.
  • the wound body 950 includes a negative electrode 931, a positive electrode 932, and a separator 933.
  • the wound body 950 is a wound body in which a negative electrode 931 and a positive electrode 932 are stacked on top of each other with a separator 933 in between, and the laminated sheet is wound. Note that a plurality of layers of the negative electrode 931, the positive electrode 932, and the separator 933 may be stacked.
  • a secondary battery 913 having a wound body 950a as shown in FIG. 14 may be used.
  • a wound body 950a shown in FIG. 14A includes 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 with the negative electrode active material layer 931a and the positive electrode active material layer 932a. Further, 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. Further, the wound body 950a having such a shape is preferable because it has good safety and productivity.
  • the negative electrode 931 is electrically connected to the terminal 951 by ultrasonic bonding, welding, or crimping.
  • Terminal 951 is electrically connected to terminal 911a.
  • the positive electrode 932 is electrically connected to the terminal 952 by ultrasonic bonding, welding, or crimping.
  • Terminal 952 is electrically connected to terminal 911b.
  • the wound body 950a and the electrolyte are covered by the casing 930, forming a secondary battery 913.
  • the housing 930 is provided with a safety valve, an overcurrent protection element, and the like.
  • the safety valve is a valve that opens the inside of the casing 930 at a predetermined internal pressure in order to prevent the battery from exploding.
  • the secondary battery 913 may have a plurality of wound bodies 950a. By using a plurality of wound bodies 950a, the secondary battery 913 can have a larger discharge capacity.
  • the description of the secondary battery 913 shown in FIGS. 13A to 13C can be referred to.
  • FIGS. 15A and 15B an example of an external view of an example of a laminate type secondary battery is shown in FIGS. 15A and 15B.
  • 15A and 15B have a positive electrode 503, a negative electrode 506, a separator 507, an exterior body 509, a positive lead electrode 510, and a negative lead electrode 511.
  • FIG. 16A shows an external view of the positive electrode 503 and negative electrode 506.
  • the positive electrode 503 has a positive electrode current collector 501 , and the positive electrode active material layer 502 is formed on the surface of the positive electrode current collector 501 . Further, the positive electrode 503 has a region (hereinafter referred to as a tab region) where the positive electrode current collector 501 is partially exposed.
  • the negative electrode 506 has a negative electrode current collector 504 , and the negative electrode active material layer 505 is formed on the surface of the negative electrode current collector 504 . Further, the negative electrode 506 has a region where the negative electrode current collector 504 is partially exposed, that is, a tab region. Note that the area or shape of the tab regions of the positive electrode and the negative electrode is not limited to the example shown in FIG. 16A.
  • FIG. 13B shows a stacked negative electrode 506, separator 507, and positive electrode 503.
  • an example is shown in which five sets of negative electrodes and four sets 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 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 joining.
  • the tab regions of the negative electrodes 506 are bonded to each other, and the negative lead electrode 511 is bonded to the tab region of the outermost negative electrode.
  • a negative electrode 506, a separator 507, and a positive electrode 503 are placed on the exterior body 509.
  • the exterior body 509 is bent at the portion indicated by the broken line. After that, the outer peripheral portion of the exterior body 509 is joined. For example, thermocompression bonding or the like may be used for joining. At this time, a region (hereinafter referred to as an inlet) that is not joined is provided in a part (or one side) of the exterior body 509 so that the electrolyte can be introduced later.
  • an inlet a region (hereinafter referred to as an inlet) that is not joined is provided in a part (or one side) of the exterior body 509 so that the electrolyte can be introduced later.
  • the electrolytic solution is introduced into the interior of the exterior body 509 from the introduction port provided in the exterior body 509.
  • the electrolytic solution is preferably introduced under a reduced pressure atmosphere or an inert atmosphere.
  • connect the inlet In this way, a laminate type secondary battery 500 can be manufactured.
  • a secondary battery can typically be applied to an automobile.
  • automobiles include next-generation clean energy vehicles such as hybrid vehicles (HV), electric vehicles (EV), and plug-in hybrid vehicles (PHEV or PHV).
  • a secondary battery can be applied.
  • Vehicles are not limited to automobiles.
  • vehicles include trains, monorails, ships, submersibles (deep sea exploration vehicles, unmanned submarines), flying vehicles (helicopters, unmanned aerial vehicles (drones), airplanes, rockets, artificial satellites), electric bicycles, electric motorcycles, etc.
  • the secondary battery of one embodiment of the present invention can be applied to these vehicles.
  • the electric vehicle includes first batteries 1301a and 1301b as main drive secondary batteries, and a second battery 1311 that supplies power to an inverter 1312 that starts a motor 1304. is installed.
  • the second battery 1311 is also called a cranking battery (also called a starter battery).
  • the second battery 1311 only needs to have a high output, and a large capacity is not required, and the capacity of the second battery 1311 is smaller than that of the first batteries 1301a and 1301b.
  • the internal structure of the first battery 1301a may be a wound type shown in FIG. 13C or FIG. 14A, or a stacked type shown in FIG. 15A or FIG. 15B.
  • this embodiment shows an example in which two first batteries 1301a and 1301b are connected in parallel, three or more may be connected in parallel. Furthermore, if the first battery 1301a can store sufficient power, the first battery 1301b may not be necessary.
  • a battery pack that includes a plurality of secondary batteries, a large amount of electric power can be extracted.
  • a plurality of secondary batteries may be connected in parallel, may be connected in series, or may be connected in parallel and then further connected in series.
  • a plurality of secondary batteries is also called an assembled battery.
  • the first battery 1301a has a service plug or circuit breaker that can cut off high voltage without using tools. provided.
  • the electric power of the first batteries 1301a and 1301b is mainly used to rotate the motor 1304, but it is also used to power 42V-based in-vehicle components (electric power steering 1307, heater 1308, defogger 1309, etc.) via a DCDC circuit 1306. ). Even when the rear motor 1317 is provided on the rear wheel, the first battery 1301a is used to rotate the rear motor 1317.
  • the second battery 1311 supplies power to 14V vehicle components (audio 1313, power window 1314, lamps 1315, etc.) via the DCDC circuit 1310.
  • FIG. 17A shows an example in which nine square secondary batteries 1300 are used as one battery pack 1415. Further, nine prismatic secondary batteries 1300 are connected in series, one electrode is fixed by a fixing part 1413 made of an insulator, and the other electrode is fixed by a fixing part 1414 made of an insulator.
  • this embodiment shows an example in which the battery is fixed using the fixing parts 1413 and 1414, it may also be configured to be housed in a battery housing box (also referred to as a housing). Since it is assumed that a vehicle is subjected to vibrations or shaking from the outside (road surface, etc.), it is preferable to fix the plurality of secondary batteries using fixing parts 1413, 1414, a battery housing box, or the like.
  • one electrode is electrically connected to the control circuit section 1320 by a wiring 1421.
  • the other electrode is electrically connected to the control circuit section 1320 by a wiring 1422.
  • FIG. 17B shows an example of a block diagram of the battery pack 1415 shown in FIG. 17A.
  • the control circuit section 1320 includes a switch section 1324 including at least a switch for preventing overcharging and a switch for preventing overdischarge, a control circuit 1322 for controlling the switch section 1324, and a voltage measuring section for the first battery 1301a. has.
  • the control circuit section 1320 has an upper limit voltage and a lower limit voltage set for the secondary battery to be used, and limits the upper limit of the current from the outside or the upper limit of the output current to the outside.
  • the range of the secondary battery's lower limit voltage to upper limit voltage is within the recommended voltage range, and when it is outside that range, the switch section 1324 is activated and functions as a protection circuit.
  • control circuit section 1320 can also be called a protection circuit because it controls the switch section 1324 to prevent overdischarge and/or overcharge. For example, when the control circuit 1322 detects a voltage that is likely to cause overcharging, the switch section 1324 is turned off to cut off the current. Furthermore, a PTC element may be provided in the charging/discharging path to provide a function of cutting off the current in response to a rise in temperature. Further, the control circuit section 1320 has an external terminal 1325 (+IN) and an external terminal 1326 (-IN).
  • the switch section 1324 can be configured by combining n-channel transistors or p-channel transistors.
  • the switch section 1324 is not limited to a switch having an Si transistor using single crystal silicon, but includes, for example, Ge (germanium), SiGe (silicon germanium), GaAs (gallium arsenide), GaAlAs (gallium aluminum arsenide), InP (phosphide).
  • the switch portion 1324 may be formed using a power transistor including indium (indium), SiC (silicon carbide), ZnSe (zinc selenide), GaN (gallium nitride), GaOx (gallium oxide; x is a real number greater than 0), or the like.
  • the first batteries 1301a and 1301b mainly supply power to 42V system (high voltage system) on-board equipment, and the second battery 1311 supplies power to 14V system (low voltage system) onboard equipment.
  • the second battery 1311 a lead-acid battery is often used because it is advantageous in terms of cost.
  • the second battery 1311 may be a lead-acid battery, an all-solid-state battery, or an electric double layer capacitor.
  • regenerated energy from the rotation of the tires 1316 is sent to the motor 1304 via the gear 1305, and charged to the second battery 1311 from the motor controller 1303 or the battery controller 1302 via the control circuit section 1321.
  • the first battery 1301a is charged from the battery controller 1302 via the control circuit section 1320.
  • the first battery 1301b is charged from the battery controller 1302 via the control circuit unit 1320. In order to efficiently charge the regenerated energy, it is desirable that the first batteries 1301a and 1301b can be rapidly charged.
  • the battery controller 1302 can set the charging voltage, charging current, etc. of the first batteries 1301a and 1301b.
  • the battery controller 1302 can set charging conditions according to the charging characteristics of the secondary battery to be used and perform rapid charging.
  • the outlet of the charger or the connection cable of the charger is electrically connected to the battery controller 1302.
  • Power supplied from an external charger charges the first batteries 1301a and 1301b via the battery controller 1302.
  • a control circuit is provided and the function of the battery controller 1302 is not used in some cases, but in order to prevent overcharging, the first batteries 1301a and 1301b are charged via the control circuit section 1320. It is preferable.
  • the connecting cable or the connecting cable of the charger is provided with a control circuit.
  • the control circuit section 1320 is sometimes called an ECU (Electronic Control Unit).
  • the ECU is connected to a CAN (Controller Area Network) provided in the electric vehicle.
  • CAN is one of the serial communication standards used as an in-vehicle LAN.
  • the ECU includes a microcomputer. Further, the ECU uses a CPU or a GPU.
  • External chargers installed at charging stations etc. include 100V outlet-200V outlet, or 3-phase 200V and 50kW. It is also possible to charge the battery by receiving power from an external charging facility using a non-contact power supply method or the like.
  • the capacity decrease is suppressed even when the electrode layer is made thicker and the loading amount is increased, and the synergistic effect of maintaining high capacity has resulted in a secondary battery with significantly improved electrical characteristics.
  • It is particularly effective for secondary batteries used in vehicles, and provides a vehicle with a long cruising range, specifically a cruising range of 500 km or more on one charge, without increasing the weight ratio of the secondary battery to the total vehicle weight. be able to.
  • the secondary battery of this embodiment described above can have a high operating voltage by using the positive electrode active material 101 described in Embodiment 1, and can be used as the charging voltage increases. Capacity can be increased. Further, by using the positive electrode active material 101 described in Embodiment 1 for the positive electrode, a secondary battery for a vehicle with excellent safety can be provided.
  • next-generation clean energy such as a hybrid vehicle (HV), electric vehicle (EV), or plug-in hybrid vehicle (PHV) can be realized.
  • HV hybrid vehicle
  • EV electric vehicle
  • PSV plug-in hybrid vehicle
  • a car can be realized.
  • secondary batteries in agricultural machinery, motorized bicycles including electric assist bicycles, motorcycles, electric wheelchairs, electric carts, ships, submarines, aircraft, rockets, artificial satellites, space probes, planetary probes, or spacecraft. It can also be installed.
  • the secondary battery of one embodiment of the present invention can be a high capacity secondary battery. Therefore, the secondary battery of one embodiment of the present invention is suitable for reduction in size and weight, and can be suitably used for transportation vehicles.
  • a car 2001 shown in FIG. 18A is an electric car that uses an electric motor as a power source for driving. Alternatively, it is a hybrid vehicle that can appropriately select and use an electric motor and an engine as a power source for driving.
  • a secondary battery is mounted on a vehicle, the example of the secondary battery shown in Embodiment 5 is installed at one or multiple locations.
  • a car 2001 shown in FIG. 18A includes a battery pack 2200, and the battery pack includes a secondary battery module to which a plurality of secondary batteries are connected. Furthermore, it is preferable to include a charging control device electrically connected to the secondary battery module.
  • the automobile 2001 can be charged by receiving power from an external charging facility using a plug-in method, a non-contact power supply method, or the like to a secondary battery of the automobile 2001.
  • a predetermined charging method or connector standard such as CHAdeMO (registered trademark) or combo may be used as appropriate.
  • the charging equipment may be a charging station provided at a commercial facility or may be a home power source.
  • plug-in technology it is possible to charge the power storage device mounted on the vehicle 2001 by supplying power from the outside. Charging can be performed by converting AC power into DC power via a conversion device such as an ACDC converter.
  • a power receiving device can be mounted on a vehicle, and power can be supplied from a ground power transmitting device in a non-contact manner for charging.
  • this non-contact power supply method by incorporating a power transmission device into the road or outside wall, charging can be performed not only while the vehicle is stopped but also while the vehicle is running. Further, electric power may be transmitted and received between two vehicles using this contactless power supply method.
  • a solar cell may be provided on the exterior of the vehicle, and the secondary battery may be charged when the vehicle is stopped or traveling.
  • an electromagnetic induction method or a magnetic resonance method can be used.
  • FIG. 18B shows a large transport vehicle 2002 having an electrically controlled motor as an example of a transport vehicle.
  • the secondary battery module of the transport vehicle 2002 has a maximum voltage of 170V, for example, in which four secondary batteries with a nominal voltage of 3.0 V or more and 5.0 V or less are connected in series, and 48 cells are connected in series. Except for the difference in the number of secondary batteries constituting the secondary battery module of the battery pack 2201, etc., it has the same functions as those in FIG. 18A, so a description thereof will be omitted.
  • FIG. 18C shows, as an example, a large transport vehicle 2003 with an electrically controlled motor.
  • the secondary battery module of the transportation vehicle 2003 has a maximum voltage of 600 V, for example, by connecting in series one hundred or more secondary batteries with a nominal voltage of 3.0 V or more and 5.0 V or less. Therefore, a secondary battery with small variations in characteristics is required.
  • a secondary battery in which the positive electrode active material 101 described in Embodiments 1 to 3 is used as a positive electrode a secondary battery having stable battery characteristics can be manufactured, and from the viewpoint of yield, it can be manufactured in large quantities at low cost. Production is possible. Further, except for the difference in the number of secondary batteries constituting the secondary battery module of the battery pack 2202, etc., it has the same functions as those in FIG. 17A, so a description thereof will be omitted.
  • FIG. 18D shows an example aircraft 2004 with an engine that burns fuel. Since the aircraft 2004 shown in FIG. 18D has wheels for takeoff and landing, it can be said to be part of a transportation vehicle, and a secondary battery module is configured by connecting a plurality of secondary batteries, and the aircraft 2004 is connected to a secondary battery module and charged.
  • the battery pack 2203 includes a control device.
  • the secondary battery module of the aircraft 2004 has a maximum voltage of 32V, for example, by connecting eight 4V secondary batteries in series. Except for the difference in the number of secondary batteries constituting the secondary battery module of the battery pack 2203, etc., it has the same functions as those in FIG. 18A, so a description thereof will be omitted.
  • FIG. 18E shows an artificial satellite 2005 equipped with a secondary battery 2204 as an example. Since the artificial satellite 2005 is used in outer space, it is desired that there be no failure due to ignition, and it is preferable to include the secondary battery 2204, which is an aspect of the present invention and has excellent safety. Furthermore, it is more preferable that the secondary battery 2204 is mounted inside the artificial satellite 2005 while being covered with a heat insulating member.
  • FIG. 19A is an example of an electric bicycle using the power storage device of one embodiment of the present invention.
  • the power storage device of one embodiment of the present invention can be applied to an electric bicycle 8700 illustrated in FIG. 19A.
  • a power storage device according to one embodiment of the present invention includes, for example, a plurality of storage batteries and a protection circuit.
  • the electric bicycle 8700 includes a power storage device 8702.
  • the power storage device 8702 can supply electricity to a motor that assists the driver. Further, the power storage device 8702 is portable, and FIG. 19B shows a state in which it has been removed from the bicycle. Further, the power storage device 8702 includes a plurality of built-in storage batteries 8701 included in the power storage device of one embodiment of the present invention, and can display the remaining battery level and the like on a display portion 8703.
  • Power storage device 8702 also includes a control circuit 8704 that can control charging or detect abnormality of a secondary battery, an example of which is shown in Embodiment 6. The control circuit 8704 is electrically connected to the positive and negative electrodes of the storage battery 8701.
  • the positive electrode active material 101 obtained in Embodiment 1 with a secondary battery using the positive electrode as the positive electrode, a synergistic effect regarding safety can be obtained.
  • the secondary battery and control circuit 8704 using the positive electrode active material 101 obtained in Embodiment 1 as a positive electrode are highly safe and can greatly contribute to eradicating accidents such as fires caused by secondary batteries.
  • FIG. 19C is an example of a two-wheeled vehicle using the power storage device of one embodiment of the present invention.
  • a scooter 8600 shown in FIG. 19C includes a power storage device 8602, a side mirror 8601, and a direction indicator light 8603.
  • the power storage device 8602 can supply electricity to the direction indicator light 8603.
  • the power storage device 8602 that houses a plurality of secondary batteries using the positive electrode active material 101 obtained in Embodiment 1 as a positive electrode can have a high capacity and can contribute to miniaturization.
  • the scooter 8600 shown in FIG. 19C can store a power storage device 8602 in an under-seat storage 8604.
  • the power storage device 8602 can be stored in the under-seat storage 8604 even if the under-seat storage 8604 is small.
  • a secondary battery which is one embodiment of the present invention, is mounted in an electronic device
  • electronic devices incorporating secondary batteries include television devices (also called televisions or television receivers), computer monitors, digital cameras, digital video cameras, digital photo frames, mobile phones (mobile phones, Examples include mobile phone devices (also referred to as mobile phone devices), portable game machines, personal digital assistants, audio playback devices, and large game machines such as pachinko machines.
  • portable information terminals include notebook personal computers, tablet terminals, electronic book terminals, and mobile phones.
  • FIG. 20A shows an example of a mobile phone.
  • the mobile phone 2100 includes a display section 2102 built into a housing 2101, as well as operation buttons 2103, an external connection port 2104, a speaker 2105, a microphone 2106, and the like.
  • the mobile phone 2100 includes a secondary battery 2107.
  • a secondary battery 2107 in which the positive electrode active material 101 described in Embodiment 1 is used as a positive electrode, a high capacity can be achieved, and a configuration can be realized that can accommodate space saving due to downsizing of the housing. Can be done.
  • the mobile phone 2100 can execute various applications such as mobile phone calls, e-mail, text viewing and creation, music playback, Internet communication, computer games, etc.
  • the operation button 2103 can have various functions such as turning on and off the power, turning on and off wireless communication, executing and canceling silent mode, and executing and canceling power saving mode.
  • the functions of the operation buttons 2103 can be freely set using the operating system built into the mobile phone 2100.
  • the mobile phone 2100 is capable of performing short-range wireless communication according to communication standards. For example, by communicating with a headset capable of wireless communication, it is also possible to make hands-free calls.
  • the mobile phone 2100 is equipped with an external connection port 2104, and can directly exchange data with other information terminals via a connector. Charging can also be performed via the external connection port 2104. Note that the charging operation may be performed by wireless power supply without using the external connection port 2104.
  • the mobile phone 2100 has a sensor.
  • a human body sensor such as a fingerprint sensor, a pulse sensor, a body temperature sensor, a touch sensor, a pressure sensor, an acceleration sensor, or the like.
  • the mobile phone 2100 may be configured to include an external battery 2150.
  • External battery 2150 has a secondary battery and a plurality of terminals 2151.
  • the external battery 2150 can charge a mobile phone 2100 or the like via a cable 2152 or the like.
  • the positive electrode active material of one embodiment of the present invention for a secondary battery included in the external battery 2150, the external battery 2150 can have high performance.
  • the capacity of the secondary battery 2107 included in the main body of the mobile phone 2100 is small, it can be used for a long time by charging from the external battery 2150. Therefore, it is possible to make the main body of the mobile phone 2100 smaller and/or lighter, and to improve safety.
  • the product may include only the external battery 2150.
  • the external battery 2150 can charge various types of portable information terminals in addition to the mobile phone 2100.
  • FIG. 20B is an unmanned aircraft 2300 with multiple rotors 2302.
  • Unmanned aerial vehicle 2300 is sometimes called a drone.
  • Unmanned aircraft 2300 includes a secondary battery 2301, which is one embodiment of the present invention, a camera 2303, and an antenna (not shown).
  • Unmanned aerial vehicle 2300 can be remotely controlled via an antenna.
  • a secondary battery using the positive electrode active material 101 obtained in Embodiment 1 as a positive electrode has a high energy density and is highly safe, so it can be used safely for a long time and is suitable for use in the unmanned aerial vehicle 2300. It is suitable as a secondary battery to be mounted.
  • FIG. 20C shows an example of a robot.
  • the robot 6400 shown in FIG. 20C includes a secondary battery 6409, an illuminance sensor 6401, a microphone 6402, an upper camera 6403, a speaker 6404, a display section 6405, a lower camera 6406, an obstacle sensor 6407, a movement mechanism 6408, a calculation device, and the like.
  • the microphone 6402 has a function of detecting the user's speaking voice, environmental sounds, and the like. Furthermore, the speaker 6404 has a function of emitting sound.
  • the robot 6400 can communicate with a user using a microphone 6402 and a speaker 6404.
  • the display unit 6405 has a function of displaying various information.
  • the robot 6400 can display information desired by the user on the display section 6405.
  • the display unit 6405 may include a touch panel. Further, the display unit 6405 may be a removable information terminal, and by installing it at a fixed position on the robot 6400, charging and data exchange are possible.
  • the upper camera 6403 and the lower camera 6406 have a function of capturing images around the robot 6400. Further, the obstacle sensor 6407 can detect the presence or absence of an obstacle in the direction of movement of the robot 6400 when the robot 6400 moves forward using the moving mechanism 6408.
  • the robot 6400 uses an upper camera 6403, a lower camera 6406, and an obstacle sensor 6407 to recognize the surrounding environment and can move safely.
  • the robot 6400 includes a secondary battery 6409 according to one embodiment of the present invention and a semiconductor device or electronic component in its internal area.
  • a secondary battery using the cathode active material 101 obtained in Embodiment 1 as a cathode has high energy density and is highly safe, so it can be used safely for a long time and can be mounted on the robot 6400. It is suitable as the secondary battery 6409.
  • FIG. 20D shows an example of a cleaning robot.
  • the cleaning robot 6300 includes a display portion 6302 placed on the top surface of a housing 6301, a plurality of cameras 6303 placed on the side, a brush 6304, an operation button 6305, a secondary battery 6306, various sensors, and the like.
  • the cleaning robot 6300 is equipped with tires, a suction port, and the like.
  • the cleaning robot 6300 is self-propelled, detects dirt 6310, and can suck the dirt from a suction port provided on the bottom surface.
  • the cleaning robot 6300 can analyze the image taken by the camera 6303 and determine the presence or absence of obstacles such as walls, furniture, or steps. Furthermore, if an object such as wiring that is likely to become entangled with the brush 6304 is detected through image analysis, the rotation of the brush 6304 can be stopped.
  • the cleaning robot 6300 includes a secondary battery 6306 according to one embodiment of the present invention and a semiconductor device or an electronic component in its internal area.
  • a secondary battery using the positive electrode active material 101 obtained in Embodiment 1 as a positive electrode has a high energy density and is highly safe, so it can be used safely for a long time and is suitable for the cleaning robot 6300. This is suitable as the secondary battery 6306 to be mounted.
  • FIG. 21 is a graph of the internal temperature of the secondary battery (hereinafter simply referred to as temperature) versus time, and shows that as the temperature rises, thermal runaway occurs through several states.
  • the negative electrode decomposes, and finally (7) the positive electrode and negative electrode come into direct contact.
  • the secondary battery reaches thermal runaway after going through the above-mentioned state (5), (6), or (7).
  • thermal runaway it is necessary to suppress the temperature rise of the secondary battery, and to maintain a stable state at high temperatures of the negative electrode, positive electrode and/or electrolyte exceeding 100°C. It will be done.
  • the positive electrode active material 101 which is one embodiment of the present invention, has a stable crystal structure and has the effect of suppressing oxygen desorption. Therefore, it is thought that the secondary battery using the positive electrode active material 101 does not reach at least the state after the above (5), and the temperature rise of the secondary battery is suppressed, and has the remarkable effect of being less likely to cause thermal runaway.
  • the nail penetration test is a test in which a nail 1003 satisfying a predetermined diameter selected from 2 mm or more and 10 mm or less is inserted into the secondary battery 500 at a predetermined speed selected from 1 mm/s or more and 20 mm/s or less. be. In this embodiment and the examples described below, the secondary battery 500 is fully charged (States of Charge: SOC 100%).
  • FIG. 22A shows a cross-sectional view of the secondary battery 500 with a nail 1003 inserted therein.
  • the secondary battery 500 has a structure in which a positive electrode 503, a separator 507, a negative electrode 506, and an electrolyte 530 are housed in an exterior body 531.
  • the positive electrode 503 has a positive electrode current collector 501 and a positive electrode active material layer 502 formed on both sides thereof, and the negative electrode 506 has a negative electrode current collector 504 and a negative electrode active material layer 505 formed on one or both sides thereof.
  • FIG. 22B shows an enlarged view of the nail 1003 and the positive electrode current collector 501, and clearly shows the positive electrode active material 101, which is one embodiment of the present invention, and the conductive material 553, which the positive electrode active material layer 502 has.
  • FIG. 22C shows an enlarged view of the positive electrode active material 101.
  • the positive electrode active material 101 has the characteristics as described in the above embodiment.
  • FIG. 23 is a partially revised graph based on the graph shown on page 70 [FIG. 2-12] of Non-Patent Document 4, and is a graph of the temperature of the secondary battery against time, and is a graph of the temperature of the secondary battery with respect to time.
  • the transition metal M is reduced by the electrons rapidly flowing into the positive electrode active material (for example, cobalt changes from Co 4+ to Co 2+ ), and a reaction occurs in which oxygen is released from the positive electrode active material. There is. Since this reaction is exothermic, positive feedback is applied to thermal runaway. That is, if this reaction can be suppressed, a positive electrode active material that is less likely to undergo thermal runaway can be obtained.
  • the surface layer portion of the positive electrode active material which tends to become a site for the above-mentioned reaction, has a crystal structure that makes it difficult to release oxygen.
  • the concentration of a metal that is difficult to release oxygen is high. If oxygen is difficult to be released from the positive electrode active material, the above-mentioned reduction reaction (for example, the reaction from Co 4+ to Co 2+ ) is also suppressed.
  • the metal that does not easily release oxygen is a metal that forms a stable metal oxide, such as magnesium and aluminum. Nickel is also considered to have the effect of suppressing oxygen release when present at the lithium site. It is also thought to have the effect of suppressing thermite reaction between the aluminum foil used for the positive electrode current collector and the positive electrode active material.
  • the positive electrode active material 101 When a nail penetration test was performed on a secondary battery using the positive electrode active material 101 which is one embodiment of the present invention, it was found that the positive electrode active material 101 had the unique effect of suppressing oxygen release because it had the above-mentioned barrier film. It is thought that the oxidation reaction of the electrolytic solution is suppressed and heat generation is also suppressed. Further, according to the positive electrode active material 101, since the barrier film in the surface layer has characteristics similar to an insulator, it is thought that the speed of current flowing into the positive electrode at the time of an internal short circuit becomes slow. It is expected that this will have the remarkable effect of making it difficult for thermal runaway to occur and for fires to occur.
  • the transition metal M such as cobalt
  • the transition metal M such as cobalt
  • positive electrode active materials with and without additive elements were prepared, and their safety was evaluated.
  • Nickel sulfate, cobalt sulfate, and manganese sulfate were prepared as the nickel source, cobalt source, and manganese source in step S111 of FIG. 6A, and first glycine was prepared as the chelating agent S113. In step S114, these were mixed with water to obtain an acid solution. In the acid solution, the combined concentration of cobalt sulfate, nickel sulfate, and manganese sulfate was 2 mol/L, and the concentration of the first glycine was 0.100 mol/L.
  • sodium hydroxide dissolved in pure water sodium hydroxide aqueous solution
  • concentration of sodium hydroxide was adjusted to 5 mol/L.
  • the water shown in S122 of FIG. 6A was an aqueous solution containing the second glycine. This was adjusted so that the second glycine concentration was 0.100 mol/L.
  • the aqueous solution containing the second glycine is also referred to as a filling solution.
  • a baffle plate is installed in the reaction container of the coprecipitation device, the charging solution is filled, the stirring is done with a stirrer at a rotation speed of 1000 rpm, the temperature is adjusted to maintain 50°C and the pH is 11.0, and the reaction container is heated. Nitrogen was supplied from the top at a rate of 1 L/min, and preparations were made to drop an aqueous sodium hydroxide solution to maintain the above pH. The rate of addition of the acid solution was 0.10 mL/min. Co-precipitation reaction proceeded in the reaction vessel. After the dropwise addition was completed, the liquid temperature was maintained at 25°C. OptiMax (manufactured by Mettler Toledo) was used as a coprecipitation device (step S131).
  • step S132 in FIG. 6A the suspension produced by the coprecipitation reaction was suction-filtered with pure water, and then suction-filtered with acetone to obtain a precipitate. Thereafter, according to step S133, the precipitate was dried in a vacuum drying oven at 200° C. for 12 hours to obtain composite hydroxide 98.
  • the composite hydroxide 98 may be called a precursor.
  • lithium hydroxide was prepared as a lithium source in S141 of FIG.
  • Lithium hydroxide was crushed in a fluidized bed jet mill at 10,000 rpm for 50 minutes or more.
  • no additional element source was mixed in S141.
  • step S142 the molar ratio of lithium hydroxide to the precursor (hereinafter referred to as Li/Co or Li/(Ni+Co+Mn)) was adjusted and mixed to be 1.01. Mixing was performed three times at 1500 rpm using an autorotating/revolving mixer.
  • step S143 in FIG. 7 the mixture obtained above was heated.
  • the heating conditions in step S143 were 700° C. for 10 hours.
  • a roller hearth kiln simulator furnace manufactured by Noritake Company
  • oxygen was flowed at a flow rate of 10 L/min.
  • step S144 was heated again in step S145.
  • the heating conditions in step S145 were the same as in step S143, except that the heating conditions were 800° C. for 10 hours.
  • the composite oxide 99 can function as a positive electrode active material even at this stage. Further, the atomic ratio of the positive electrode active material obtained through such a process may not be equal to the molar ratio adjusted at the time of weighing the raw materials.
  • An additive element source was prepared as step S151 in FIG.
  • calcium carbonate was used as the additive element source.
  • Calcium carbonate was adjusted to be 1 mol% of composite oxide 99 and mixed (step S152).
  • step S153 in FIG. 7 the mixture obtained above was heated.
  • the heating conditions in step S153 were the same as in step S143, except that the heating conditions were 800° C. for 2 hours. Thereafter, it was cooled to room temperature and crushed in step S154 to obtain the positive electrode active material 101 (step S175). This was designated as sample 1.
  • Sample 2 was prepared in the same manner as Sample 1, except that the steps after step S151 were not performed and no additional elements were added.
  • Table 3 shows an excerpt of the manufacturing conditions for Sample 1 and Sample 2.
  • the above sample 1 or sample 2 was prepared as a positive electrode active material, acetylene black (AB) was prepared as a conductive material, and polyvinylidene fluoride (PVDF) was prepared as a binder. PVDF was prepared in advance by dissolving it in N-methyl-2-pyrrolidone (NMP) at a weight ratio of 5%. Next, a positive electrode active material: AB:PVDF was mixed at a ratio of 95:3:2 (weight ratio) to prepare a slurry, and the slurry was applied to a positive electrode current collector. Aluminum foil (both mirror surfaces) with a thickness of 20 ⁇ m was used as the positive electrode current collector. NMP was used as a solvent for the slurry. After applying the slurry to the positive electrode current collector, the solvent was evaporated.
  • NMP N-methyl-2-pyrrolidone
  • pressing treatment was performed using a roll press machine.
  • the conditions for the press treatment were a linear pressure of 210 kN/m.
  • both the upper roll and lower roll of the roll press machine were set to 120 degreeC.
  • Graphite was prepared as a negative electrode active material.
  • CMC and SBR were prepared as binders.
  • Carbon fiber manufactured by Showa Denko K.K., VGCF (registered trademark)
  • VGCF registered trademark
  • a porous polypropylene film with a thickness of 25 ⁇ m was used as the separator.
  • An aluminum laminate film in which nylon, aluminum, and polypropylene were laminated was used for the exterior body.
  • Table 4 shows the manufacturing conditions for the secondary battery manufactured using the above materials.
  • Initial charging and discharging were performed for these secondary batteries. Initial charging and discharging is sometimes called aging or conditioning.
  • a nail penetration test was conducted on the cell containing Sample 1 or Sample 2.
  • the nail penetration tester used was Advanced Safety Tester manufactured by ESPEC Co., Ltd. A nail with a diameter of 3 mm was used. The speed of the nail piercing operation was 1 mm/s. The amount of nail penetration was set to the cell thickness plus 6 mm. Regarding other points, the nail penetration test was conducted in accordance with the description of SAE J2464 "Safety and abuse test for electric/hybrid vehicle power storage system".
  • FIG. 24A is a photograph showing a nail penetration test of a secondary battery having Sample 1
  • FIG. 24B is a photograph showing a state of a nail penetration test of a secondary battery having Sample 2. No ignition was observed in either case.
  • FIG. 25A is a graph showing voltage changes of a secondary battery having Sample 1 or Sample 2 in a nail penetration test.
  • Sample 1 containing the additive element the voltage suddenly decreased immediately after the nail was inserted, returned to 3.5 V or higher, and then slowly decreased again.
  • Sample 2 which did not contain any additive elements, the voltage suddenly decreased immediately after the nail was inserted, and although the voltage returned soon after, it did not recover to 2.5V or higher.
  • FIG. 25B is a graph showing the temperature change of the secondary battery having Sample 1 or Sample 2 in the nail penetration test.
  • the temperature increase was 15° C. or less.
  • the temperature rise was 30° C. or more.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
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  • Inorganic Chemistry (AREA)
  • Organic Chemistry (AREA)
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  • Secondary Cells (AREA)

Abstract

La présente invention concerne un nouveau matériau actif d'électrode positive. La présente invention concerne également une batterie secondaire de sûreté élevée. Cette batterie secondaire au lithium-ion comporte une électrode positive, l'électrode positive présentant un matériau actif d'électrode positive, le matériau actif d'électrode positive contenant du nickel, du cobalt, du manganèse, de l'oxygène et des éléments additifs. Les éléments additifs sont au moins un ou deux éléments choisis parmi le fluor, l'aluminium, le magnésium, le titane et le calcium. Le matériau actif d'électrode positive comprend une couche présentant une grande quantité d'éléments additifs, et un intérieur, la couche présentant une grande quantité d'éléments additifs présentant au moins un élément choisi parmi des éléments additifs dont la quantité est supérieure à celle de l'intérieur.
PCT/IB2023/056234 2022-06-29 2023-06-16 Batterie secondaire et procédé de production de matériau actif d'électrode positive WO2024003662A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013232438A (ja) * 2013-08-05 2013-11-14 Toda Kogyo Corp リチウム複合化合物粒子粉末及びその製造方法、非水電解質二次電池
JP2015530721A (ja) * 2013-08-29 2015-10-15 エルジー・ケム・リミテッド リチウム遷移金属複合粒子、この製造方法、及びこれを含む正極活物質
JP2021516434A (ja) * 2018-04-04 2021-07-01 エルジー・ケム・リミテッド リチウム二次電池用正極活物質の製造方法、リチウム二次電池用正極活物質、これを含むリチウム二次電池用正極及びリチウム二次電池
JP2022501789A (ja) * 2018-10-26 2022-01-06 エルジー・ケム・リミテッド 二次電池用正極活物質、その製造方法及びそれを含むリチウム二次電池

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013232438A (ja) * 2013-08-05 2013-11-14 Toda Kogyo Corp リチウム複合化合物粒子粉末及びその製造方法、非水電解質二次電池
JP2015530721A (ja) * 2013-08-29 2015-10-15 エルジー・ケム・リミテッド リチウム遷移金属複合粒子、この製造方法、及びこれを含む正極活物質
JP2021516434A (ja) * 2018-04-04 2021-07-01 エルジー・ケム・リミテッド リチウム二次電池用正極活物質の製造方法、リチウム二次電池用正極活物質、これを含むリチウム二次電池用正極及びリチウム二次電池
JP2022501789A (ja) * 2018-10-26 2022-01-06 エルジー・ケム・リミテッド 二次電池用正極活物質、その製造方法及びそれを含むリチウム二次電池

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