JP6520624B2 - Charging device and charging method - Google Patents

Description

  The present invention relates to a battery charging device and a battery charging method.

  In recent years, with the spread of electrically powered vehicles, the demand for secondary batteries for driving the vehicles is expanding. In these electric vehicles, in order to improve the fuel efficiency and the mountability, higher capacity and smaller size of the secondary battery are expected, and the performance improvement of the secondary battery is required. Among secondary batteries, non-aqueous electrolyte secondary batteries, particularly lithium ion batteries, can be used for driving various electric vehicles because they can be increased in capacity.

  Generally, a non-aqueous electrolyte secondary battery includes a positive electrode having a positive electrode active material layer having a positive electrode material represented by a positive electrode active material formed on the surface of a positive electrode current collector, and a negative electrode active material layer having a negative electrode active material. The negative electrode formed on the surface of the current collector is connected via the non-aqueous electrolyte, and is housed in the case. In a lithium ion battery, which is a typical example of a non-aqueous electrolyte secondary battery, a lithium composite oxide is used as a positive electrode material. For example, Patent Documents 1 to 6 describe lithium composite oxides that can be used as a positive electrode material.

Patent Document 1 describes that Li _x CoMO ₂ and LiNiMnMO ₂ are mixed to form a positive electrode active material. Here, M is a predetermined element. The positive electrode active material includes an active material having a high average voltage at the time of discharge and an active material having high thermal stability.

Patent Document 2 describes a positive electrode active material including a crystal layer of a layered rock salt type structure of LiNiMnTiO ₂ . By containing Ti, the positive electrode active material can obtain a higher charge / discharge capacity as compared to the case where it does not contain Ti.

Patent Document 3 describes that Li _x MnMO ₄ and LiNiMO ₂ are mixed to form a positive electrode active material. Here, M is a predetermined element. By using this positive electrode active material, the battery performance after high temperature storage can be made excellent.

Patent Document 4 describes a positive electrode active material in which a part of Li in LiMnMO ₂ having a layered polycrystalline structure is deficient. Here, M is a predetermined element. This positive electrode active material stabilizes distortion and chemical bonds in the crystal, and can improve cycle stability, durability stability, and the like during charge and discharge.

Patent Document 5 describes a positive electrode active material in which part of Li and Co in LiCoO ₂ is replaced with a predetermined element M, respectively. In this positive electrode active material, when each of Li and Co is substituted by the element M, the bonding strength between the lithium layer and the cobalt layer is strengthened, distortion of the layer and expansion of the crystal lattice are suppressed, and during charge and discharge Cycle stability, durability stability and the like can be improved.

Patent Document 6 describes that LiNiMnCoO ₂ and Li ₂ MO ₃ are mixed to form a positive electrode active material. Here, M is a predetermined element. The positive electrode active material has an active material that exerts an effect excellent in battery capacity and safety, and an active material exerting an effect on cycle characteristics and storage characteristics. However, in any of these positive electrode active materials, the collapse of the crystal structure at the time of charge and discharge can not be sufficiently suppressed, and there is a problem that the capacity of the non-aqueous electrolyte secondary battery is lowered.

Further, Non-Patent Document 1 describes a technology of using a Ti-containing positive electrode, that is, LiNiMnTiO _{2 in} terms of safety. However, as described in Non-Patent Document 1, it is described that the addition of Ti does not provide an overwhelming improvement in safety.

In Non-Patent Document 2, as another attempt for achieving both safety and high stabilization of crystals, a positive electrode containing Si having a strong bonding force with oxygen in the same amount as the transition metal, ie, Li ₂ MnSiO ₄ Technology is described. However, in this positive electrode, the transition metal has a four-coordinate coordination structure, which destabilizes the structure at the time of charging, and it has not been possible to construct a positive electrode having sufficient durability.

JP 2007-188703 A JP, 2008-127233, A JP 2001-345101 A JP 2001-250551 A Patent No. 3782058 gazette JP, 2006-202702, A "Synthesis of LiNi0.5Mn0.5-xTixO2 by an Emulsion Drying Method and Effect of Properties on Electrochemical Properties," Chemistry of Materials, 2005, Volume 17, P2427-2435 "Li2MSiO4 (M = Fe and / or Mn) cathode materials", Journal of Power Sources, 2008, Vol. 184, P462-P468.

In order to solve the above problems, the present inventors pay attention to the structure of the positive electrode material, have a six-coordinated structure as a local structure of the transition metal, and contain a large amount of an element strongly binding to oxygen and I found that I could solve the above-mentioned problems. This novel positive electrode material has a layered rock salt type crystal structure, a transition metal having a six-coordinated local structure, and is represented by the chemical formula Li _2-x Ni _α M ¹ _β M ² _γ O _4-ε It contains lithium transition metal oxide. Here, 0.50 <α ≦ 1.33, 0 ≦ β <0.67, 0 ≦ γ ≦ 1.33, M ¹ is at least ^one of Co, Al and Ga, M ² is Mn, Ge, By inserting and extracting at least one of Sn and Sb and lithium ions, the range of 0 ≦ x ≦ 2 is reversibly changed. However, while investigating the electrochemical characteristics of the novel positive electrode material, the novel positive electrode material was found to have a feature that the resistance of the battery at the time of charging was significantly increased when the residual capacity decreased.

  The reason for having such characteristics is that as a result of intensive studies, in the region where the residual capacity is less than the characteristic change threshold value, based on the strong covalent bond with oxygen such as Sn and Ge in order to secure a new lithium diffusion path. It is considered that the mass transfer in the strong layered rock salt type crystal is necessary, but the diffusion path is already formed in the region where the residual capacity is equal to or more than the characteristic change threshold, and the additional mass transfer is not necessary. . In the present invention, the remaining capacity means the remaining capacity as a battery below. And when this remaining capacity is low, it has the characteristic that resistance is high. And, as described above, it is considered that this high resistance is derived from the structural change of the positive electrode material in the process of forming the lithium diffusion path. The irreversible capacity generated in the positive electrode active material at the time of initial charge and discharge is also found. The above-mentioned remaining capacity does not necessarily coincide with the lithium desorption amount in the above-mentioned chemical formula of the positive electrode active material. Even after the initial charge and discharge that produces a certain irreversible capacity, as described above, when the battery contains a large amount of lithium, high resistance is achieved to form and secure a new lithium diffusion path at the time of battery output, that is, It has been found that it has high resistance, low resistance threshold.

  By the way, a hybrid vehicle or an electric vehicle is equipped with a motor that generates a driving force for driving the vehicle. In addition, a lithium ion battery that supplies power to the motor is mounted. When the motor generates a driving force for driving a vehicle, the lithium ion battery supplies power to the motor. On the other hand, when the motor is in a regenerative state, the electric power generated by the motor is supplied to the lithium ion battery to charge the lithium ion battery. Thereby, the electric power generated by the motor in the regenerative state can be effectively used. As a result, the efficiency of the hybrid vehicle or the electric vehicle can be improved.

  When a battery composed of the above-mentioned novel positive electrode material is applied to such a hybrid vehicle or an electric vehicle, when the remaining capacity decreases, electric power is supplied to the battery composed of the new positive electrode material from the motor in a regenerative state. At the time, there is a concern that the heat generation amount and the power consumption increase due to the rise in resistance, the life becomes short, and the regenerative power can not be sufficiently used. In addition, even when charging from an external commercial power source such as an electric car or a plug-in hybrid car, if the remaining capacity decreases, there is a concern that the amount of heat generated during charging and the power consumption will increase due to the increase in resistance.

   The present invention has been made in view of such circumstances, and it is possible to supply electric power to a battery composed of a novel positive electrode material while suppressing the temperature rise of the battery and the increase of power consumption at the time of charging. It aims at providing an apparatus and a charge method.

The first invention made to achieve the above object has a layered rock salt type crystal structure, and the transition metal has a six-coordinated local structure, and the chemical formula Li _2-x Ni _α M ¹ _β M ² _γ O _4-ε (where, 0.50 <α ≦ 1.33, 0 ≦ β <0.67, 0 ≦ γ ≦ 1.33, M ¹ is at least ^one of Co, Al and Ga, M ² (A) reversibly changes the range of 0 ≦ x ≦ 2 by occluding and releasing lithium ion and at least one of Mn, Ge, Sn and Sb; If the resistance is higher than the characteristic change threshold when the remaining capacity is less than the characteristic change threshold and the resistance is 0% when the remaining capacity is 0%, the resistance is twice as high as the characteristic change threshold. Battery with the above characteristics and normal charging A main power supply that supplies power to the battery to charge the battery by flowing current, and a lead storage battery or commercial that outputs ac storage battery or AC that supplies power to the battery to charge the battery by flowing a pre-charging current smaller than the normal charging current If the remaining power of the auxiliary power supply provided with the power supply (230) and the battery is less than the characteristic change threshold, the auxiliary power is controlled to supply power to the battery from the auxiliary power supply, and the remaining capacity of the battery becomes at least the characteristic change threshold And a control unit for charging the battery.

  According to this configuration, when the remaining capacity of the battery is less than the characteristic change threshold, power is supplied to the battery from the auxiliary power supply, and the battery is charged until the remaining capacity of the battery reaches at least the characteristic change threshold. Therefore, it is possible to eliminate the situation where power is supplied from the main power source to the battery in a state where the remaining capacity of the battery is less than the characteristic change threshold value, that is, in a state where the resistance is large. Therefore, power can be supplied to the battery from the main power supply without reducing the current. Moreover, when the remaining capacity of the battery is less than the characteristic change threshold, the battery is charged by supplying a pre-charging current smaller than the normal charging current. Therefore, even if the remaining capacity becomes less than the characteristic change threshold and the resistance increases, the temperature rise of the battery and the increase in power consumption can be suppressed.

The second invention made to achieve the above object has a layered rock salt type crystal structure, and the transition metal has a six-coordinated local structure, and the chemical formula Li _2-x Ni _α M ¹ _β M ² _γ O _4-ε (where, 0.50 <α ≦ 1.33, 0 ≦ β <0.67, 0 ≦ γ ≦ 1.33, M ¹ is at least ^one of Co, Al and Ga, M ² (A) reversibly changes the range of 0 ≦ x ≦ 2 by occluding and releasing lithium ion and at least one of Mn, Ge, Sn and Sb; If the resistance is higher than the characteristic change threshold when the remaining capacity is less than the characteristic change threshold and the resistance is 0% when the remaining capacity is 0%, the resistance is twice as high as the characteristic change threshold. Has the above characteristics, and usually A method of charging a battery to which power is supplied and charged by flowing an electric current, the system comprising a lead storage battery or a commercial power supply (230) for outputting alternating current when the remaining capacity of the battery is less than the characteristic change threshold. Power is supplied to the battery by supplying a precharging current smaller than the normal charging current from a power supply different from the power supply, and the battery is charged until the remaining capacity of the battery reaches at least a characteristic change threshold.

  According to this method, when the remaining capacity of the battery is less than the characteristic change threshold, power is supplied to the battery from a power source different from the main power supply, and the battery is charged until the remaining capacity of the battery reaches at least the characteristic change threshold. Therefore, it is possible to eliminate the situation where power is supplied from the main power source to the battery in a state where the remaining capacity of the battery is less than the characteristic change threshold value, that is, in a state where the resistance is large. Therefore, power can be supplied to the battery from the main power supply without reducing the current. Moreover, when the remaining capacity of the battery is less than the characteristic change threshold, the battery is charged by supplying a pre-charging current smaller than the normal charging current. Therefore, even if the remaining capacity becomes less than the characteristic change threshold and the resistance increases, the temperature rise of the battery and the increase in power consumption can be suppressed.

It is a circuit diagram of the charging device in a 1st embodiment. It is a perspective view of the lithium ion battery which comprises the battery in FIG. It is the III-III arrow sectional drawing in FIG. It is a graph which shows the characteristic of resistance with respect to the remaining capacity of the battery in FIG. It is a graph which shows the characteristic of the characteristic change threshold value periphery in FIG. It is a flowchart for demonstrating the operation | movement of the charging device in FIG. FIG. 6 is a first circuit diagram for illustrating the operation of the charging device in FIG. 1; FIG. 6 is a second circuit diagram for illustrating the operation of the charging device in FIG. 1; FIG. 7 is a third circuit diagram for illustrating the operation of the charging device in FIG. 1; It is a circuit diagram of the charging device in a 2nd embodiment. It is a flowchart for demonstrating the operation | movement of the charging device in FIG. FIG. 11 is a first circuit diagram for illustrating the operation of the charging device in FIG. 10. FIG. 11 is a second circuit diagram for illustrating the operation of the charging device in FIG. 10.

  Next, the present invention will be described in more detail by way of embodiments. In this embodiment, the example which applied the charging device which concerns on this invention to the charging device mounted in a vehicle is shown.

First Embodiment
First, the configuration of the charging device of the first embodiment will be described with reference to FIGS. 1 to 5.

  The charging device 1 shown in FIG. 1 is a device for charging a battery 10 mounted on a vehicle. The charging device 1 includes a battery 10, a power conversion circuit 11, a motor 12, an auxiliary power supply 13, and a control circuit 14. Here, the power conversion circuit 11 and the motor 12 correspond to the main power supply of the present invention. The control circuit 14 corresponds to the control unit of the present invention.

  The battery 10 is a chargeable / dischargeable secondary battery that supplies power to the motor 12 via the power conversion circuit 11. The battery 10 is configured by connecting a plurality of lithium ion batteries 100 shown in FIGS. 2 and 3.

  The lithium ion battery 100 includes a positive electrode 100a, a negative electrode 100b, a non-aqueous electrolyte 100c, a separator 100d, and a case 100e.

  The positive electrode 100a includes a positive electrode current collector 100f and a positive electrode active material layer 100g.

  The positive electrode current collector 100 f is a thin plate-like member made of a metal such as aluminum.

The positive electrode active material layer 100 g is made of an oxide capable of absorbing and desorbing lithium ions, and is formed on the surface of the positive electrode current collector 100 f. The oxide forming the positive electrode active material layer 100 g has a layered rock salt type crystal structure, a transition metal having a six-coordinated local structure, and a chemical formula Li _2-x Ni _α M ¹ _β M ² _γ O _{4 −ε} (where, 0.50 <α ≦ 1.33, 0 ≦ β <0.67, 0 ≦ γ ≦ 1.33, M ¹ is at least ^one of Co, Al and Ga, M ² is Mn And at least one of Ge, Sn, and Sb, which reversibly changes the range of 0 ≦ x ≦ 2 by occluding and releasing lithium ions, as a positive electrode active material. It is. The positive electrode active material layer 100 g is formed by mixing the above-mentioned oxide together with a conductive material, a binder and the like in a solvent, and applying and drying it on the surface of the positive electrode current collector 100 f. The conductive material is, for example, a carbon material or a conductive polymer material. The carbon material is ketjen black, acetylene black, carbon black, graphite, carbon nanotube, amorphous carbon or the like. Also, the conductive polymer material is polyaniline, polypyrrole, polythiophene, polyacetylene, polyacene. The binder is, for example, a polymer material. The polymer material is polyvinylidene fluoride, polytetrafluoroethylene, ethylene propylene rubber, styrene butadiene rubber, nitrile rubber, fluoro rubber, acrylic binder. The solvent is, for example, water, N-methyl-2-pyrrolidone.

  The negative electrode 100 b includes a negative electrode current collector 100 h and a negative electrode active material layer 100 i.

  The negative electrode current collector 100 h is a thin plate-like member made of a metal such as Cu.

  The negative electrode active material layer 100i is made of a compound capable of absorbing and releasing lithium ions, and is formed on the surface of the negative electrode current collector 100h. The compound which forms the negative electrode active material layer 100i is, for example, a metal material such as lithium foil, an alloy material containing Si, Sn, Cu or the like, a carbon material such as graphite or coke, or a titanium oxide. The negative electrode active material layer 100i is prepared by mixing the above-described compound forming the negative electrode active material layer 100i with the same conductive material and binder as the positive electrode 100a in the same solvent as the positive electrode 100a, and then using the negative electrode current collector 100h. It is formed by applying and drying on the surface of.

  The non-aqueous electrolyte 100 c enables movement of charge carriers such as ions between the positive electrode 100 a and the negative electrode 100 b.

  The separator 100d is a thin plate-like member that insulates the positive electrode 100a from the negative electrode 100b while allowing movement of charge carriers between the positive electrode 100a and the negative electrode 100b. The separator 100d is, for example, a porous synthetic resin film, in particular, a porous film made of a polyolefin polymer, cellulose, glass fiber, or a non-woven fabric. The separator 100d may contain ceramics as its component.

  The case 100e is a member that accommodates the positive electrode 100a, the negative electrode 100b, the separator 100d, and the non-aqueous electrolyte 100c. The case 100 e is formed of, for example, a laminate film. The case 100e includes a positive electrode terminal 100j and a negative electrode terminal 100k. The positive electrode terminal 100 j and the negative electrode terminal 100 k are fixed to the case 100 e in a state in which one end portion protrudes into the internal space of the case 100 e and the other end portion protrudes outside the case 100 e.

  The positive electrode 100a and the negative electrode 100b are alternately stacked. The separator 100d is provided between the positive electrode 100a and the negative electrode 100b. The positive electrode 100a, the negative electrode 100b, and the separator 100d are accommodated in the internal space of the case 100e. The end of the positive electrode 100a is connected to the positive electrode terminal 100j, and the end of the negative electrode 100b is connected to the negative electrode terminal 100k. The non-aqueous electrolyte 100c is accommodated in the internal space of the case 100e together with the positive electrode 100a, the negative electrode 100b, and the separator 100d.

In the battery 10, the oxide forming the positive electrode active material layer 100 g has a layered rock salt type crystal structure, the transition metal has a six-coordinated local structure, and the chemical formula Li _2-x Ni _α M ¹ _β M ² _γ O _4-ε (where, 0.50 <α ≦ 1.33, 0 ≦ β <0.67, 0 ≦ γ ≦ 1.33, M ¹ is at least ^one of Co, Al and Ga, M ² reversibly changes the range of 0 ≦ x ≦ 2 by occluding and releasing lithium ion and at least one of Mn, Ge, Sn, and Sb; It contains as an active material. As a result, compared with the case where such a substance is not contained, the safety is high and the capacity per volume can be further increased. In addition, when the residual capacity is less than the characteristic change threshold, the resistance is larger than the resistance when the characteristic change threshold or higher, and when the residual capacity is 0%, the resistance is twice or more the resistance in the characteristic change threshold or higher. Have the following characteristics. Here, the characteristic change threshold value is a remaining capacity indicating a boundary at which the value of the resistance changes, in the graph showing the characteristic of the resistance with respect to the remaining capacity of the battery 10. For example, as shown in FIGS. 4 and 5, the resistance of the battery 10 in the case where the remaining capacity is less than 2% is higher than the resistance in the case where the remaining capacity is 2% or more. Furthermore, the resistance of the battery 10 at the remaining capacity of 0% is 5 times or more than the resistance at 2% or more.

  The reason why the battery 10 has such characteristics is that, in the region where the residual capacity is less than the characteristic change threshold as a result of intensive studies, it is based on covalent bonding of Sn or Ge and oxygen to secure a new lithium diffusion path. While mass transfer including heavy elements such as Sn and Ge is necessary when deforming inside a strong layered rock salt type crystal, a diffusion path is already formed in the region where the residual capacity is equal to or higher than the characteristic change threshold. And it is believed that no further mass transfer is necessary.

  The power conversion circuit 11 shown in FIG. 1 is controlled by the control circuit 14 and converts a direct current supplied from the battery 10 into a three-phase alternating current and supplies it to the motor 12 to drive the motor 12 to drive the vehicle. Is a circuit that generates It is also a circuit that charges the battery 10 and the auxiliary power supply 13 by converting the three-phase alternating current generated by the motor 12 in the regenerative state into direct current and supplying the direct current to the battery 10 and the auxiliary power supply 13. The power conversion circuit 11 is connected to the battery 10, the motor 12 and the auxiliary power supply 13 respectively. It is also connected to the control circuit 14.

  The motor 12 is a device that generates a driving force for driving a vehicle by being supplied with a three-phase alternating current. It is also a device that generates three-phase alternating current when in the regenerative state. The motor 12 is connected to the power conversion circuit 11.

  The auxiliary power supply 13 is a chargeable and dischargeable power supply which is controlled by the control circuit 14 and supplies power to the battery 10 to charge the battery 10. The auxiliary power supply 13 includes at least one of a lead storage battery, a lithium ion battery, a nickel hydrogen battery, and a capacitor. The auxiliary power supply 13 is set to have a smaller resistance than the battery 10 so as to supply power to the battery 10.

  The control circuit 14 is a circuit that estimates these remaining capacities based on information obtained from the battery 10 and the auxiliary power supply 13, and controls the power conversion circuit 11 and the auxiliary power supply 13 based on the estimated remaining capacities. . When the driving force for driving the vehicle is generated in the motor 12, the control circuit 14 controls the power conversion circuit 11 to convert direct current supplied from the battery 10 into three-phase alternating current and supply the same to the motor 12.

  When charging the battery 10, if the remaining capacity of the battery 10 is equal to or greater than the characteristic change threshold, the control circuit 14 controls the power conversion circuit 11 to convert the three-phase alternating current generated by the motor 12 in the regenerative state into direct current. It converts and supplies power to the battery 10 to charge the battery 10. At this time, power is normally supplied to the battery 10 by supplying a charging current. The normal charging current is determined according to the current value that can be supplied to the battery 10 in the regenerative state, and the remaining capacity of the battery 10 is set based on the resistance of the battery 10 at or above the characteristic change threshold. On the other hand, when the remaining capacity of the battery 10 is less than the characteristic change threshold, the control circuit 14 controls the auxiliary power supply 13 to supply power from the auxiliary power supply 13 to the battery 10, and the remaining capacity of the battery 10 is at least characteristic. The battery 10 is charged until the change threshold is reached. At this time, power is supplied to the battery 10 by flowing a pre-charging current smaller than the normal charging current. The pre-charging current is set based on the resistance of the battery 10 when the battery 10 residual capacity is less than the characteristic change threshold value. When the remaining capacity of the auxiliary power supply 13 is less than the auxiliary power supply charging threshold, the control circuit 14 controls the power conversion circuit 11 to convert the three-phase alternating current generated by the motor 12 in the regenerative state into direct current to Power is supplied to the power supply 13 to charge the auxiliary power supply 13. Here, the auxiliary power supply charge threshold value indicates the remaining capacity of the auxiliary power supply 13 which is required at the minimum when the battery 10 is charged by supplying power from the auxiliary power supply 13 to the battery 10.

  Next, the operation of the charging device of the first embodiment will be described with reference to FIGS. 1 and 6 to 9.

  As shown in FIG. 6, in step S100, the control circuit 14 shown in FIG. 1 estimates the remaining capacity of the battery 10 based on the information obtained from the battery 10. Then, in step S101, it is determined whether the estimated remaining capacity of the battery 10 is equal to or greater than the characteristic change threshold value.

  When it is determined that the estimated remaining capacity of the battery 10 is less than the characteristic change threshold value, the resistance of the battery 10 is larger than in the case where it is equal to or higher than the characteristic change threshold value. Therefore, it is necessary to reduce the resistance by making the remaining capacity of the battery 10 equal to or higher than the characteristic change threshold. Therefore, in step S102, the control circuit 14 pre-charges the battery 10. Specifically, the auxiliary power supply 13 is controlled, and power is supplied to the battery 10 by supplying a pre-charging current smaller than the normal charging current from the auxiliary power supply 13 to the battery 10 as shown in FIG. To charge. Thereby, the temperature rise of the battery 10 at the time of charge and the increase in power consumption can be suppressed. Then, as shown in FIG. 6, the preliminary charging of the battery 10 is repeated until the estimated remaining capacity of the battery 10 becomes equal to or greater than the characteristic change threshold value. That is, the precharging of the battery 10 is repeated until the remaining capacity of the battery 10 reaches at least the characteristic change threshold value. Thereby, the resistance of the battery 10 can be reduced.

  On the other hand, when it is determined that the estimated remaining capacity of the battery 10 is equal to or greater than the characteristic change threshold, the resistance of the battery 10 is small. Therefore, it is not necessary to pre-charge the battery 10 as described above.

  Thereafter, in step S103, the control circuit 14 estimates the remaining capacity of the auxiliary power supply 13 based on the information obtained from the auxiliary power supply 13. Then, in step S104, it is determined whether the estimated remaining capacity of the auxiliary power supply 13 is equal to or greater than the auxiliary power supply charging threshold.

  If it is determined that the estimated remaining capacity of the auxiliary power supply 13 is equal to or greater than the auxiliary power supply charging threshold, sufficient power for precharging the battery 10 is secured in the auxiliary power supply 13, and it is necessary to charge the auxiliary power supply 13 Absent. Therefore, in step S105, the control circuit 14 normally charges the battery 10. Specifically, when the regeneration state occurs at an arbitrary timing, the power conversion circuit 11 is controlled to convert the three-phase alternating current generated by the motor 12 in the regeneration state into a direct current to supply power to the battery 10 And charge the battery 10. More specifically, the power conversion circuit 11 is controlled, and power is supplied to the battery 10 by flowing a normal charging current from the power conversion circuit 11 to the battery 10 as shown in FIG. 8 to charge the battery 10.

  On the other hand, as shown in FIG. 6, when it is determined that the estimated remaining capacity of the auxiliary power supply 13 is less than the auxiliary power supply charging threshold, sufficient power for precharging the battery 10 is secured in the auxiliary power supply 13. The auxiliary power supply 13 needs to be charged. Therefore, in step S106, the control circuit 14 normally charges the battery 10 and also charges the auxiliary power supply 13. Specifically, the power conversion circuit 11 is controlled in a regeneration state which occurs at an arbitrary timing, and as shown in FIG. 9, the battery 10 is normally charged. Further, it controls the power conversion circuit 11, converts the three-phase alternating current generated by the motor 12 in the regenerative state into direct current, supplies power to the auxiliary power supply 13, and also charges the auxiliary power supply 13. Thereby, the electric power for the precharging of the battery 10 can be secured by effectively using the electric power generated by the motor 12 in the regenerative state.

  Next, the effect of the charging device of the first embodiment will be described.

According to the first embodiment, the charging device 1 includes the battery 10, the power conversion circuit 11, the motor 12, the auxiliary power supply 13, and the control circuit 14. The battery 10 has a layered rock salt type crystal structure, and has a transition metal six-coordinated local structure, and has a chemical formula Li _2-x Ni _α M ¹ _β M ² _γ O _4-ε (here, 0. 0. 50 <α ≦ 1.33, 0 ≦ β <0.67, 0 ≦ γ ≦ 1.33, M ¹ is at least ^one of Co, Al and Ga, M ² is at least Mn, Ge, Sn, Sb A lithium transition metal oxide represented by 1), which reversibly changes the range of 0 ≦ x ≦ 2 by occluding and releasing lithium ions, is included as a positive electrode active material. As a result, the resistance when the remaining capacity is less than the characteristic change threshold is larger than the resistance when the characteristic change threshold or more, and the resistance when the remaining capacity is 0% is twice or more the resistance when the characteristic change threshold or more Will have the following characteristics. The control circuit 14 controls the power conversion circuit 11, converts the three-phase alternating current generated by the motor 12 in the regenerative state into direct current, supplies power to the battery 10, and charges the battery 10. Then, when the remaining capacity of battery 10 is less than the characteristic change threshold, control circuit 14 controls auxiliary power supply 13 to supply power from auxiliary power supply 13 to battery 10, and the remaining capacity of battery 10 is at least the characteristic change threshold. The battery 10 is charged until That is, as the charging method, when the remaining capacity of the battery 10 is less than the characteristic change threshold value, the motor 12 in the regenerative state and the power conversion circuit 11 controlled by the control circuit 14 are not used. Power is supplied to the battery 10 by supplying a precharging current smaller than the normal charging current from the auxiliary power supply 13 controlled by the control circuit 14. Then, the battery 10 is charged until the remaining capacity of the battery 10 reaches at least the characteristic change threshold value. Therefore, in the state where the remaining capacity of the battery 10 is less than the characteristic change threshold value, that is, in the state where the resistance is large, a situation where power is supplied to the battery 10 from the motor 12 in the regenerative state via the power conversion circuit 11 is eliminated. be able to. Therefore, power can be supplied to the battery 10 from the motor 12 in the regenerative state without reducing the current via the power conversion circuit 11. Moreover, when the remaining capacity of the battery 10 is less than the characteristic change threshold, the battery 10 is charged by supplying a pre-charging current smaller than the normal charging current. Therefore, even if the remaining capacity falls below the characteristic change threshold and the resistance increases, the temperature rise of the battery 10 and the increase in power consumption can be suppressed. Therefore, the situation where the life of the battery 10 becomes short can be suppressed.

  The auxiliary power supply 13 charges the battery 10 by precharging when the remaining capacity of the battery 10 is less than the characteristic change threshold value. According to the first embodiment, the characteristic change threshold of the battery 10 is 2%, which is very small. Therefore, it is not necessary to pre-charge the battery 10 until the remaining capacity is less than 2%. Therefore, the interval from the precharging to the precharging can be extended. That is, the number of times of preliminary charging can be suppressed. As a result, frequent precharging can be suppressed.

  According to the first embodiment, the auxiliary power supply 13 can be charged and discharged. When the remaining capacity is less than the auxiliary power supply charging threshold, power is supplied and charged. Therefore, sufficient power for precharging can be reliably ensured. Therefore, the battery 10 can be reliably precharged as needed.

  According to the first embodiment, when the remaining capacity of the auxiliary power supply 13 is less than the auxiliary power supply charging threshold, the control circuit 14 controls the power conversion circuit 11 to generate the three-phase alternating current generated by the motor 12 in the regenerative state. It converts into direct current and supplies power to the auxiliary power supply 13 to charge the auxiliary power supply 13. Therefore, the auxiliary power supply 13 can be charged reliably. Moreover, the auxiliary power supply 13 is charged using the power generated by the motor 12 in the regenerative state. Therefore, the efficiency of the charging device 1 can be improved.

  According to the first embodiment, the auxiliary power supply 13 includes at least one of a lead storage battery, a lithium ion battery, a nickel hydrogen battery, and a capacitor. Therefore, the power for precharging can be ensured.

  According to the first embodiment, the auxiliary power supply 13 is set to have a smaller resistance than the battery 10. Therefore, it is possible to suppress the loss of the auxiliary power supply 13 at the time of precharging and at the time of charging the auxiliary power supply 13.

  In the first embodiment, an example in which the characteristic change threshold of the battery 10 is 2% is given, but the present invention is not limited to this. The characteristic change threshold value of the battery 10 may be a predetermined value of 10% or less, or may be a predetermined value of 15% or less. If it is a predetermined value of 20% or less, frequent precharging can be suppressed within the practical range.

Second Embodiment
Next, the charging device of the second embodiment will be described. While the charging apparatus of the second embodiment supplies power to the lithium ion battery from the chargeable and dischargeable auxiliary power supply of the first embodiment, the charging apparatus of the second embodiment uses an auxiliary power supply including a commercial power supply and a power conversion circuit. It is intended to supply power to a lithium ion battery. Therefore, unlike the charging device of the first embodiment, the auxiliary power supply can not be charged.

  First, the configuration of the charging apparatus of the second embodiment will be described with reference to FIG.

  As shown in FIG. 10, the charging device 2 includes a battery 20, a power conversion circuit 21, a motor 22, an auxiliary power supply 23, and a control circuit 24.

  The battery 20, the power conversion circuit 21, and the motor 22 are the same as the battery 10, the power conversion circuit 11, and the motor 12 of the first embodiment, and are configured in the same manner.

  The auxiliary power supply 23 is controlled by the control circuit 24 and supplies power to the battery 20 to charge the battery 20. Unlike the auxiliary power supply 13 of the first embodiment, it can not be charged. It has only the function of supplying power to the battery 20. The auxiliary power supply 23 is set to have a smaller resistance than the battery 20 so that power can be supplied to the battery 20. The auxiliary power supply 23 includes a commercial power supply 230 and a power conversion circuit 231.

  The commercial power source 230 is a power source that outputs alternating current provided in a house or the like. The power conversion circuit 231 is a circuit which is controlled by the control circuit 24 and converts alternating current supplied from the commercial power source 230 into direct current and supplies the direct current to the battery 20 to charge the battery 20. The power conversion circuit 231 is connected to the commercial power source 230 and the battery 20 respectively. It is also connected to the control circuit 24.

  The control circuit 24 is a circuit that estimates the remaining capacity of the battery 20 based on the information obtained from the battery 20 and controls the power conversion circuit 21 and the auxiliary power supply 23 based on the estimated remaining capacity of the battery 20. When the driving force for driving the vehicle is generated in the motor 22, the control circuit 24 controls the power conversion circuit 21 to convert direct current supplied from the battery 20 into three-phase alternating current and supply it to the motor 22.

  When charging the battery 20, when the remaining capacity of the battery 20 is equal to or greater than the characteristic change threshold, the control circuit 24 controls the power conversion circuit 21 to convert the three-phase alternating current generated by the motor 22 in the regenerative state into direct current. It converts and supplies power to the battery 20 to charge the battery 20. At this time, power is normally supplied to the battery 20 by supplying a charging current. The normal charging current is determined according to the current value that can be supplied to the battery 20 in the regenerative state, and the remaining capacity of the battery 20 is set based on the resistance of the battery 20 at or above the characteristic change threshold. On the other hand, when the remaining capacity of the battery 20 is less than the characteristic change threshold, the control circuit 24 controls the power conversion circuit 231 to convert alternating current supplied from the commercial power source 230 into direct current to supply power to the battery 20. The battery 20 is supplied and charged until the remaining capacity of the battery 20 reaches at least a characteristic change threshold. At this time, power is supplied to the battery 20 by flowing a pre-charging current smaller than the normal charging current. The preliminary charging current is set based on the resistance of the battery 20 when the battery 20 residual capacity is less than the characteristic change threshold. After preliminary charging has been performed, charging may be continued from the auxiliary power supply 23 with normal charging current. After preliminary charging has been performed, charging may be continued from the auxiliary power supply 23 with normal charging current.

  Next, the operation of the charging device of the second embodiment will be described with reference to FIGS. 10 to 13.

  As shown in FIG. 11, in step S200, the control circuit 24 shown in FIG. 10 estimates the remaining capacity of the battery 20 based on the information obtained from the battery 20. Then, in step S201, it is determined whether the estimated remaining capacity of the battery 20 is equal to or greater than the characteristic change threshold value.

  When it is determined that the estimated remaining capacity of the battery 20 is less than the characteristic change threshold value, the resistance of the battery 20 is larger than in the case where it is equal to or higher than the characteristic change threshold value. Therefore, it is necessary to reduce the resistance by making the remaining capacity of the battery 20 equal to or higher than the characteristic change threshold value. Therefore, in step S202, the control circuit 24 precharges the battery 20. Specifically, the power conversion circuit 231 is controlled to convert alternating current supplied from the commercial power source 230 into direct current, and supply power to the battery 20 to charge the battery 20. More specifically, power conversion circuit 231 is controlled, and power is supplied to battery 20 by supplying a pre-charging current smaller than the normal charging current from power conversion circuit 231 to battery 20 as shown in FIG. Charge 20. As a result, it is possible to suppress the temperature rise of the battery 20 and the increase in power consumption at the time of charging. Then, as shown in FIG. 11, the preliminary charging of the battery 20 is repeated until the estimated remaining capacity of the battery 20 becomes equal to or greater than the characteristic change threshold value. That is, the precharging of the battery 20 is repeated until the remaining capacity of the battery 20 reaches at least the characteristic change threshold value. Thereby, the resistance of the battery 20 can be reduced.

  On the other hand, when it is determined that the estimated remaining capacity of the battery 20 is equal to or greater than the characteristic change threshold value, the resistance of the battery 20 is small. Therefore, it is not necessary to pre-charge the battery 20 as described above. Therefore, in step S203, the control circuit 24 normally charges the battery 20. Specifically, when the regeneration state occurs at an arbitrary timing, the power conversion circuit 21 is controlled to convert the three-phase alternating current generated by the motor 22 in the regeneration state into a direct current to supply power to the battery 20 The battery 20 is charged. More specifically, the power conversion circuit 21 is controlled, and as shown in FIG. 13, power is supplied to the battery 20 by charging a normal charging current from the power conversion circuit 21 to the battery 20 to charge the battery 20. Further, after charging from the auxiliary power supply 23 to the characteristic threshold or more with the preliminary charging current, charging may be continued from the auxiliary power supply 23 with the normal charging current.

  Next, the effect of the charging device of the second embodiment will be described.

According to the second embodiment, the charging device 2 includes the battery 20, the power conversion circuit 21, the motor 22, the auxiliary power supply 23, and the control circuit 24. The battery 20 has a layered rock salt type crystal structure, and has a transition metal six-coordinated local structure, and has a chemical formula Li _2-x Ni _α M ¹ _β M ² _γ O _4-ε (here, 0. 0. 50 <α ≦ 1.33, 0 ≦ β <0.67, 0 ≦ γ ≦ 1.33, M ¹ is at least ^one of Co, Al and Ga, M ² is at least Mn, Ge, Sn, Sb A lithium transition metal oxide represented by 1), which reversibly changes the range of 0 ≦ x ≦ 2 by occluding and releasing lithium ions, is included as a positive electrode active material. As a result, the resistance when the remaining capacity is less than the characteristic change threshold is larger than the resistance when the characteristic change threshold or more, and the resistance when the remaining capacity is 0% is twice or more the resistance when the characteristic change threshold or more Will have the following characteristics. The control circuit 24 controls the power conversion circuit 21, converts the three-phase alternating current generated by the motor 22 in the regenerative state into direct current, supplies power to the battery 20, and charges the battery 20. When the remaining capacity of the battery 20 is less than the characteristic change threshold, the control circuit 24 controls the power conversion circuit 231 to supply power from the commercial power supply 230 to the battery 20 via the power conversion circuit 231. The battery 20 is charged until the remaining capacity reaches at least the characteristic change threshold. That is, as the charging method, when the remaining capacity of the battery 20 is less than the characteristic change threshold, the motor 22 in the regenerative state and the power conversion circuit 21 controlled by the control circuit 24 are not used. Power is supplied to the battery 20 by supplying a pre-charging current smaller than the normal charging current from the commercial power source 230 through the power conversion circuit 231 controlled by the control circuit 24. Then, the battery 20 is charged until the remaining capacity of the battery 20 reaches at least the characteristic change threshold value. Therefore, in the state where the remaining capacity of the battery 20 is less than the characteristic change threshold value, that is, in the state where the resistance is large, a situation where power is supplied to the battery 20 from the motor 22 in the regenerative state via the power conversion circuit 21 is eliminated. be able to. Therefore, power can be supplied to the battery 20 from the motor 22 in the regenerative state without reducing the current via the power conversion circuit 21. Moreover, when the remaining capacity of battery 20 is less than the characteristic change threshold, battery 20 is charged by supplying a pre-charging current smaller than the normal charging current. Therefore, even if the remaining capacity falls below the characteristic change threshold and the resistance increases, the temperature rise of the battery 20 and the increase in power consumption can be suppressed. Therefore, the situation where the life of the battery 20 becomes short can be suppressed.

  According to the second embodiment, by having the same configuration as that of the first embodiment, the same effect as that of the first embodiment corresponding to the same configuration can be obtained.

  In the second embodiment, the auxiliary power supply 23 includes the commercial power supply 230 and the power conversion circuit 231. However, the present invention is not limited to this. The auxiliary power supply 23 may have an alternator.

  DESCRIPTION OF SYMBOLS 1 ... charge apparatus, 10 ... battery, 100 ... lithium ion battery, 100a ... positive electrode, 100 g ... positive electrode active material layer, 11 ... power conversion circuit, 12 ... motor, 13 · · · power supply, 14 · · · control circuit

Claims (8)

It has a layered rock salt type crystal structure, a transition metal has a six-coordinated local structure, and the chemical formula Li _2-x Ni _α M ¹ _β M ² _γ O _4-ε (where, 0.50 <α ≦ 1.33, 0 ≦ β <0.67, 0 ≦ γ ≦ 1.33, M ¹ is at least ^one of Co, Al and Ga, M ² is at least one of Mn, Ge, Sn and Sb, lithium ion Containing a lithium transition metal oxide represented by 0) xx 可逆 2 reversibly by occluding and releasing) as a positive electrode active material, and the remaining capacity is less than the characteristic change threshold value. A battery (10, 20) having a characteristic in which the resistance in the case where the remaining capacity is 0% is larger than the resistance in the case where the characteristic change threshold is equal to or more than twice the resistance in the case where the characteristic change threshold is equal to or more ,
A main power supply (11, 12, 21, 22) for supplying power to the battery by charging a normal charging current to charge the battery;
An auxiliary power supply (13, 23) comprising a lead storage battery or a commercial power supply (230) for outputting alternating current, which supplies power to the battery to charge the battery by supplying a precharging current smaller than the normal charging current;
When the remaining capacity of the battery is less than the characteristic change threshold, the auxiliary power supply is controlled to supply power from the auxiliary power to the battery, and the battery is operated until the remaining capacity of the battery reaches at least the characteristic change threshold. A control unit (14, 24) to charge;
With a charging device.   The charging device according to claim 1, wherein the characteristic change threshold of the battery is a predetermined value of 20% or less. The charging device according to claim 1 or 2, wherein the auxiliary power supply ( 13 ) provided with the lead storage battery is chargeable and dischargeable, and power is supplied and charged when the remaining capacity is less than an auxiliary power supply charging threshold.   The charging device according to claim 3, wherein the main power supply (11, 12) supplies power to the auxiliary power supply to charge the auxiliary power supply when the remaining capacity of the auxiliary power supply is less than the auxiliary power supply charging threshold. Wherein said auxiliary power supply with a commercial power supply (23), said converts the alternating current supplied to the DC from the commercial power source supplies power to the battery, and includes a power conversion circuit for charging (231) the battery The charging device according to claim 1 or 2. The charging device according to any one of claims 1 to 5 , wherein the auxiliary power supply has a smaller resistance than the battery. It has a layered rock salt type crystal structure, a transition metal has a six-coordinated local structure, and the chemical formula Li _2-x Ni _α M ¹ _β M ² _γ O _4-ε (where, 0.50 <α ≦ 1.33, 0 ≦ β <0.67, 0 ≦ γ ≦ 1.33, M ¹ is at least ^one of Co, Al and Ga, M ² is at least one of Mn, Ge, Sn and Sb, lithium ion Containing a lithium transition metal oxide represented by 0) xx 可逆 2 reversibly by occluding and releasing) as a positive electrode active material, and the remaining capacity is less than the characteristic change threshold value. Is larger than the resistance at the characteristic change threshold and the resistance at the remaining capacity is 0% is twice or more than the resistance at the characteristic change Power is supplied by passing current A method of charging a battery to be charged,
When the remaining capacity of the battery is less than the characteristic change threshold value, a preliminary charging current smaller than the normal charging current is supplied from an auxiliary power supply provided with a lead storage battery or a commercial power supply (230) outputting AC. A charging method of supplying power to the battery by flowing, and charging the battery until the remaining capacity of the battery reaches at least the characteristic change threshold. The auxiliary power supply (23), the charging method according to claim 7 which converts the alternating current supplied to the DC supplies power to the battery to charge the battery from the commercial power source.

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