Battery repairing method and battery control device

Abstract

Provided is a battery repairing method comprising: a repair necessity determination step for determining, on the basis of cell information pertaining to a battery cell including a solid electrolyte, whether repair of the battery cell is necessary; a heating step for heating the solid electrolyte to a temperature not less than a melting temperature when it has been determined in the repair necessity determination step that the repair of the battery cell is necessary; and a recrystallization step for recrystallizing, by lowering the temperature, the solid electrolyte which has been melted in the heating step.

Description

Battery repair method and battery control device

[0001] This disclosure relates to a battery repair method and a battery control device.

[0002] In drive battery systems installed in vehicles such as electric vehicles, lithium-ion secondary batteries with high energy density and power density have conventionally been used to improve the vehicle's power performance. In recent years, all-solid-state secondary batteries that use a solid electrolyte have been proposed to improve the performance and safety of drive battery systems. Such all-solid-state secondary batteries are disclosed, for example, in Patent Documents 1 to 3.

[0003] Japanese Patent Publication No. 2022-182306, Japanese Patent Publication No. 2020-017535, Japanese Patent Publication No. 2020-528655

[0004] However, conventional all-solid-state secondary batteries, including the prior art described above, have a problem in that the electrodes are prone to volume changes as they absorb and release ions during charging and discharging. In other words, repeated charging and discharging can lead to cracks forming between the electrodes and the solid electrolyte layer, or cracks developing in the electrodes themselves. In such cases, the battery cells constituting the all-solid-state secondary battery may deteriorate, potentially preventing the vehicle from achieving the expected power performance when installed in a vehicle.

[0005] This disclosure has been made in view of the above circumstances, and the object of this disclosure is to provide a battery repair method for repairing battery cells containing a solid electrolyte, and a battery control device.

[0006] To solve the above problems, according to one aspect of this disclosure, a battery repair method is provided, which includes: a repair necessity determination step of determining whether a battery cell needs to be repaired based on cell information in a battery cell containing a solid electrolyte; a heating step of applying heat to the solid electrolyte above its dissolution temperature if it is determined in the repair necessity determination step that the battery cell needs to be repaired; and a recrystallization step of recrystallizing the solid electrolyte dissolved in the heating step by cooling.

[0007] Furthermore, in order to solve the above problems, according to another aspect of this disclosure, a battery control device is provided for controlling a battery including a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, comprising: a repair necessity determination unit that determines whether or not a battery cell needs to be repaired based on cell information in the battery cell including the solid electrolyte; and a heating control unit that provides heating to the solid electrolyte at a temperature above its dissolution temperature based on the determination result of the repair necessity determination unit, wherein the heating control unit dissolves the solid electrolyte by applying an electric current between the positive electrode layer and the negative electrode layer.

[0008] As described above, this disclosure provides a battery repair method for repairing battery cells containing a solid electrolyte, and a battery control device.

[0009] This is a schematic diagram showing an example configuration of a vehicle equipped with a battery device. This is a functional block diagram showing an example configuration of a control device. This is a schematic diagram showing an example configuration of a battery device according to the first embodiment. This is a flowchart showing an example of a battery repair method according to the first embodiment. This is a flowchart showing an example of a battery repair method according to the first embodiment. This is a diagram showing an example of a repair determination according to the first embodiment. This is a diagram showing another example of a repair determination according to the first embodiment. This is a schematic diagram showing an example configuration of a battery device according to the second embodiment. This is a flowchart showing an example of a battery repair method according to the second embodiment.

[0010] [Embodiments] Preferred embodiments of the present disclosure will be described below with reference to the accompanying drawings. Note that the dimensions and scale of parts in the drawings may differ from those of the actual parts as appropriate. Also, the drawings may be schematic for the sake of ease of understanding. Furthermore, the scope of the present disclosure is not limited to the embodiments described below unless otherwise stated to specifically limit the present disclosure. In the present disclosure, "repair" of a battery includes sealing cracks between the electrode active material and the solid electrolyte by dissolving and recrystallizing the solid electrolyte. The present disclosure may also cover cracks that occur within the solid electrolyte.

[0011] <First Embodiment> (Vehicle Configuration) Figure 1 is a schematic diagram showing an example of the configuration of a vehicle 1 equipped with a battery device 90 according to this embodiment. The vehicle 1 has a plurality of motors 10. As shown in Figure 1, the vehicle 1 is a four-wheel drive vehicle equipped with a motor 10 corresponding to each of the four drive wheels 3. The motors 10 are not particularly limited, but for example, an axial gap motor (AGM) is used. A normal reduction gear may be interposed between the motors 10 and the drive wheels 3.

[0012] Vehicle 1 has an electric steering system 15 and a conventional brake fluid pressure control unit (not shown), etc. The electric steering system 15 and the brake fluid pressure control unit are controlled by a control device 60 which includes one or more electronic control units (ECUs). The electric steering system 15 has a conventional electric motor (not shown) and a gear mechanism (not shown), and adjusts the steering angle of the drive wheels 3 (left front wheel and right front wheel) based on the control of the control device 60. During manual driving, the control device 60 controls the electric steering system 15 based on the steering angle of the steering wheel 13 by the driver.

[0013] The brake system of vehicle 1 is configured as, for example, a hydraulic brake system. The brake fluid pressure control unit (not shown) described above adjusts the hydraulic pressure of the oil supplied to the brake calipers 17 provided on each of the four drive wheels 3, thereby generating braking force. The operation of such a brake fluid pressure control unit is controlled by a control device 60.

[0014] The control device 60 includes one or more electronic control units (ECUs). These ECUs control the drive of the motor 10 that outputs the drive torque of the vehicle 1, the steering wheel 13 and the electric steering device 15 that controls the steering angle of the steering wheels, and the brake fluid pressure control unit that controls the braking force of the vehicle 1.

[0015] The control device 60 functions as a device that repairs the battery devices 90 and 902, as described later, by having one or more CPUs (Central Processing Units) or other processors execute a computer program. The computer program is a computer program that causes the processor to execute the battery repair method, etc., of this disclosure. The computer program executed by the processor may be recorded on a storage device 63 (memory), a recording medium built into the control device 60, or any recording medium that can be attached externally to the control device 60, as described later.

[0016] Recording media for storing computer programs may include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as CD-ROMs, DVDs, and Blu-ray®; magneto-optical media such as floppy disks; memory elements such as RAM (Random Access Memory) and ROM (Read Only Memory); flash memory such as USB (Universal Serial Bus) memory and SSD (Solid State Drive); and other media capable of storing programs.

[0017] In addition to the visual sensor 81 and tactile sensor 82 described later, the vehicle 1 according to this embodiment may also have, for example, a GPS (Global Positioning System) sensor or a vehicle status sensor. Examples of vehicle status sensors include a vehicle speed sensor, acceleration sensor, angular velocity sensor, steering angle sensor, accelerator position sensor, brake stroke sensor, and brake pressure sensor.

[0018] The visual sensor 81 includes, for example, a conventional LiDAR (Light Detection And Ranging) 81A and forward-facing cameras 81B and 81C. The forward-facing cameras 81B and 81C and the LiDAR 81A have the function of acquiring visual information of the surrounding environment of the vehicle 1. The forward-facing cameras 81B and 81C have, for example, conventional CCD (Charged-Coupled Devices) or CMOS (Complementary Metal-Oxide-Semiconductor) image sensors.

[0019] The LiDAR 81A transmits optical waves and receives reflected waves of said optical waves, and detects an object and the distance to the object based on the time from the transmission of the optical waves to the reception of the reflected waves. The vehicle 1 may have a radar sensor or an ultrasonic sensor, etc., as a visual sensor 81 for acquiring visual information of the surrounding environment, either instead of the LiDAR 81A or in combination with the LiDAR 81A. In addition, the vehicle 1 may have, in addition to the forward-facing cameras 81B and 81C, a conventional camera, for example, mounted on a side mirror to photograph the left rear or right rear.

[0020] The tactile sensor 82 is, for example, installed on the drive wheel 3 and detects longitudinal force Fx, lateral force Fy, and vertical force Fz acting on the drive wheel 3 from the road surface on which it is traveling. There are no particular limitations on such a tactile sensor 82, and examples include a conventional tire force sensor or a hub sensor.

[0021] The inverter 16 supplies the current necessary to drive the motor 10. There are no particular restrictions on the inverter 16 in this embodiment; for example, a normal inverter capable of supplying the current necessary to drive the motor 10 can be used. In Figure 1, there is one inverter 16, but this is not the case; multiple inverters may be provided in the vehicle 1 depending on the number of motors 10, and a single inverter 16 may control the driving of multiple motors 10.

[0022] The battery device 90 supplies power to the motor 10 via the inverter 16 based on the control of the control device 60. The battery device 90 according to this embodiment is a rechargeable battery device containing a solid electrolyte. The battery device 90 may also be electrically connected to a connector C, as shown in Figure 1. The connector C functions as a plug-in (charging port) connected to a cable that connects to an external charge / discharge heating device M located outside the vehicle 1. The external charge / discharge heating device M may be mounted on a fast charger installed at a charging station (charging spot) for charging electric vehicles or at a car dealership, for example.

[0023] In Figure 1, there is one battery device 90, but this is not limited to this. Multiple battery devices may be provided in the vehicle 1 depending on the number of motors 10, and a single battery device 90 may control the driving of multiple motors 10.

[0024] The display device 50 is driven by the control device 60 and displays various information visible to the driver of the vehicle 1. The display device 50 according to this embodiment is, for example, a display device provided in the instrument panel or a display device of a navigation system. The form of the display device 50 is not particularly limited, and other display devices different from these may also be used.

[0025] Figure 2 is a block diagram showing an example configuration of the control device 60. As shown in Figure 2, the control device 60 is connected to the battery device 90 and the display device 50. The control device 60 includes a communication device 61, a processing device 62, and a storage device 63. The processing device 62 includes one or more processors such as a CPU, and various peripheral components. Part or all of the processing device 62 may be composed of updatable components such as firmware, and may also be program modules executed by commands from the CPU, etc.

[0026] The communication device 61 is a known communication circuit that is communicably connected to an external connected device (for example, the external charge / discharge heating device M). The communication device 61 functions as an input / output interface in the connection with the external connected device. The control device 60 according to the present embodiment further has a communication interface (not shown) connected to a network such as the Internet, and may be connected to an external connected device such as a server, a personal computer, a smartphone, or a tablet terminal via this network. In this case, various data may be exchanged between the control device 60 and the external connected device.

[0027] The storage device 63 is one or more recording media such as a RAM, a ROM, a HDD (Hard Disk Drive), a CD (Compact Disc), a DVD (Digital Versatile Disc), a SSD, a USB flash, or a storage device, which is communicably connected to the processing device 62. However, the type and number of the storage device 63 are not particularly limited. The storage device 63 records a computer program executed by the processing device 62, various parameters used for arithmetic processing, and data regarding arithmetic results and the like. A part of the storage device 63 is used as a work area of the processing device 62.

[0028] The memory device 63 according to this embodiment stores cell information in the battery device 90. The cell information may include, for example, information on cell voltage values, or information on cell resistance values calculated from the changes in cell voltage values and battery current. The cell information may further include cell capacity information including the capacity value of the battery cell, cell repair period information including information on past repair times in the battery cell, cell charge / discharge amount information including the charge / discharge amount within a predetermined period in the battery cell, and the like. The integrated current value during the rise or fall of the cell voltage to a predetermined value may be stored as the above cell information. More specifically, the memory device 63 may store the above information as cell information during the running of the vehicle 1 or during the charging of the battery device 90. The cell information stored in the memory device 63 may be associated with information such as the running date and time of the vehicle 1. The memory device 63 may further store the average value of all cells included in the battery with respect to the above cell information. Also, the difference between this average value and the information of an arbitrary cell may be stored as cell information.

[0029] The processing device 62 functionally includes a repair necessity determination unit 62A and a heating control unit 62B. The functions of these units are realized by the execution of a computer program by a processor. Note that a part of the repair necessity determination unit 62A and the heating control unit 62B may be configured by hardware such as an analog circuit. Note that the processing device 62 is not limited to an electronic control device mounted on the vehicle 1, and may be, for example, a laptop computer, a mobile phone, a smartphone, a wearable device, or a tablet terminal.

[0030] The repair necessity determination unit 62A has a function of determining whether a cell needs to be repaired based on the cell information stored in the above-described memory device 63. More specifically, as an example, the repair necessity determination unit 62A can determine that the repair of the cell is necessary when the cell resistance value within a predetermined time increases more than a predetermined value determined in advance. Also, as another example, the repair necessity determination unit 62A compares the integrated current value of an arbitrary cell with the average value of the integrated current values of all cells, and can determine that the repair of the cell is necessary when it becomes smaller than a predetermined value determined in advance.

[0031] The heating control unit 62B has the function of applying heating to cells that are determined to require repair among a plurality of cells, at a temperature above the dissolution temperature of the solid electrolyte contained in those cells. In other words, the heating control unit 62B has the function of controlling the repair of cells by dissolving the solid electrolyte contained in them through heating. The heating of the solid electrolyte may also be performed by applying (discharging) an electric current between the positive electrode layer and the negative electrode layer of the cell. That is, the heating control unit 62B may have the function of controlling the amount of current between the positive electrode layer and the negative electrode layer. Furthermore, the heating control unit 62B may have the function of controlling the temperature during the recrystallization of the solid electrolyte dissolved by the heating. That is, the heating control unit 62B may have the function of accelerating or slowing down the cooling rate when the solid electrolyte dissolved by heating recrystallizes.

[0032] The heating control unit 62B may display information visible to the driver of the vehicle 1 on the display device 50. This information may include, for example, information prompting the driver of the vehicle 1 to repair the battery device.

[0033] (Battery Device Configuration) Figure 3 is a schematic diagram showing an example of the configuration of the battery device 90 according to this embodiment. As shown in Figure 3, a known configuration including a solid electrolyte can be applied to the battery device 90. That is, the battery device 90 includes a battery management circuit 91, a discharge circuit 92 electrically connected to the battery management circuit 91, and battery cells 930 (hereinafter simply referred to as "cells 930") electrically connected to each of these discharge circuits.

[0034] In Figure 3, the battery device 90 is composed of four cells 930A to 930D, but it is not limited to this. That is, the battery device 90 may be composed of one cell, or it may be composed of two or more cells. Since cells 930A to 930D ​​have similar configurations, they will be described in detail below as "cell 930". As shown in Figure 3, cell 930 has a negative electrode current collector 931, a negative electrode active material layer 932, a solid electrolyte layer 933, a positive electrode active material layer 934, and a positive electrode current collector 935.

[0035] The negative electrode current collector 931 and the positive electrode current collector 935 can be applied with known metal foils or the like applicable to, for example, in-vehicle battery devices. The negative electrode current collector 931 is electrically connected to the negative electrode terminal of the battery device 90. Also, the positive electrode current collector 935 is electrically connected to the positive electrode terminal of the battery device 90.

[0036] The negative electrode active material layer 932 may contain a negative electrode active material applicable to known battery devices. The negative electrode active material layer 932 may further contain a conductive assistant and a binder for the negative electrode. The negative electrode active material is not particularly limited as long as it can occlude and release ions during charging and discharging of the battery device 90, and may be, for example, a metal such as a carbon material, Sn (tin), or In (indium). Specifically, it may be a metal powder such as natural graphite, graphite, Sn, Si (silicon), Al, Sb (antimony), Zn (zinc), or Bi (bismuth), Sn ５ Cu ６ 、Sn ２ Co or Sn ２ metal alloy powders such as Fe, amorphous alloys, or plated alloys.

[0037] The solid electrolyte layer 933 contains a solid electrolyte. The solid electrolyte has ion conductivity. The solid electrolyte is preferably a crystalline substance, and preferably a molecular crystal having a structure in which molecules are regularly arranged in the crystal lattice. Also, the solid electrolyte is preferably a substance that dissolves when heated above the melting temperature and recrystallizes when the dissolved substance is slowly cooled. The solid electrolyte is preferably a sulfide-based solid electrolyte from the viewpoint of obtaining high ion conductivity. Specifically, for example, Li ２ S and SiS ２ 、GeS ２ 、P ２ S ５ or B ５ S ３ and inorganic solid electrolytes combined with each other, and organic solid electrolytes such as Li(FSA)(SN) ２ etc. In particular, since it is stable even at room temperature or higher and high ion conductivity can be obtained even under low temperature conditions compared to other solid electrolytes, the solid electrolyte contained in the solid electrolyte layer 933 is Li(FSA)(SN)２ It is preferable that the solid electrolyte of the solid electrolyte layer 933 be Li(FSA)(SN) ２ By adopting this, the charge and discharge efficiency of cell 930 is improved and the operational stability is enhanced compared to when other solid electrolytes are used. Note that the above "FSA" stands for N(SO ２ F) ２ It means that "SN" stands for NCCH ２ CH ２ It means CN.

[0038] The positive electrode active material layer 934 may contain a positive electrode active material applicable to known battery devices. The positive electrode active material layer 934 may further contain a conductive additive and a positive electrode binder. The positive electrode active material is not particularly limited as long as it can intercept and release ions during charging and discharging of the battery device 90, but may be, for example, a composite oxide of lithium and a transition metal. Specifically, LiCoO ２ LiNiCoO ２ LiNiO ２ , LiNiCoAlO ２ , LiNiMnCoO2, LiFeMnO ２ Li ２ PtO ３ LiMnNiO ４ LiMn ２ O ４ LiNiMnO ２ LiNiVO ４ LiCrMnO ４ LiFePO ４ LiFe(SO ４ ) ３ LiCoVO ４ LiCoPO ４ , or S (sulfur), etc.

[0039] The discharge circuit 92 is electrically connected to the battery management circuit 91 and has the function of discharging to the corresponding cell 930. More specifically, the discharge circuit 92 has the function of discharging charge based on the control of the battery management circuit 91, thereby melting the solid electrolyte in the corresponding cell 930 by Joule heating.

[0040] The battery management circuit 91 has the function of driving the discharge circuit 92 based on the control of the control device 60. More specifically, the battery management circuit 91 may drive the discharge circuit 92 by activating the discharge relay drive circuit included in the battery management circuit 91. Known circuits including PNP transistors can be used as the discharge relay drive circuit. The battery management circuit 91 also has the function of controlling the charge when the discharge circuit 92 discharges to the cell 930. More specifically, the battery management circuit 91 has the function of adjusting the amount of Joule heat when dissolving the solid electrolyte by controlling the amount of charge when discharging to the cell 930. The battery management circuit 91 also has the function of controlling the temperature during the cooling process when the solid electrolyte recrystallizes due to cooling by controlling the amount of charge during discharge. That is, the battery management circuit 91 has the function of adjusting the recrystallization rate of the solid electrolyte, such as slowing it down.

[0041] Furthermore, the battery management circuit 91 has a function to acquire information on the voltage value of the cell 930. If the battery device 90 includes multiple cells, the battery management circuit 91 may also have a function to acquire the average value of the voltage values ​​of each cell 930. The battery management circuit 91 may also have a function to acquire the cell resistance value based on the acquired cell voltage value and battery current. The battery management circuit 91 may further have a function to acquire the integrated current value while the cell voltage rises or falls to a predetermined value.

[0042] (Battery Repair Method) Figures 4 and 5 are flowcharts illustrating an example of the battery repair method of this disclosure. Hereinafter, an example of the battery repair method of this disclosure will be described with appropriate reference to Figures 4 and 5.

[0043] Figure 4 is a flowchart of the repair necessity determination process. After the control device 60 is started by the ignition of the vehicle 1 (IG-ON), the repair necessity determination unit 62A first determines whether or not the cell repair flag is set (step St1). Specifically, if the cell repair flag set in the repair necessity determination process in the previous process has not been cleared (Yes in step St1), the series of processes is terminated. On the other hand, if the cell repair flag is not set (No in step St1), the repair necessity determination unit 62A performs the cell repair necessity process (step St2). If it is determined in the cell repair necessity process that cell repair is necessary (Yes in step St3), the repair necessity determination unit 62A sets the cell repair flag in the control device 60 (step St4) and also sets the wake-up timer for when the ignition is turned off (IG-OFF) (step St5), and the series of processes is terminated. On the other hand, if it is determined that cell repair is not necessary (No in step St3), the series of processes is terminated.

[0044] Figure 5 is a flowchart showing the flow when it is determined that repair is necessary in the repair necessity determination process. After the control device 60 is started by the wake-up timer (START), the repair necessity determination unit 62A sequentially performs the heating process (step St6) and the recrystallization process (step St7). Next, the repair necessity determination unit 62A clears the cell repair flag in the control device 60 (step St8) and ends the series of processes (END).

[0045] As an example of a cell repair necessity determination process, an example of determining whether repair is necessary based on cell resistance information will be explained using Figure 6. In Figure 6, the horizontal axis shows the cell resistance value acquisition timing, and the vertical axis shows the cell resistance value. Here, the cell resistance value acquisition timing may be a predetermined timing, for example, the resistance value may be acquired at predetermined time intervals. Alternatively, the timing when the battery management circuit 91 detects a current change of a predetermined value or more in the battery device 90 may be used as the cell resistance value acquisition timing. Furthermore, the timing when the battery management circuit 91 detects rapid charging of the battery device 90 may also be used as the cell resistance value acquisition timing. In Figure 6, the more recent these cell resistance value acquisition timings are displayed on the right side of the horizontal axis. That is, 1 on the horizontal axis is the most recent data, and n is the oldest data among those displayed. On the other hand, on the vertical axis, the average resistance value of all cells included in the battery device 90 is shown by ○, and the resistance value of any cell acquired at the same time is shown by ◆.

[0046] As shown in Figure 6, the repair necessity determination unit 62A can determine that cell repair is necessary if the deviation from the average value of all cells is greater than or equal to a predetermined value and the number of consecutive detections is greater than or equal to a predetermined number. For example, in Figure 6, between 12 and n on the horizontal axis, and between 7 and 8 on the horizontal axis, the difference between the resistance value of a specific cell and the average resistance value of all cells is less than a predetermined value, so the repair necessity determination unit 62A can determine that cell repair is unnecessary. Also, in Figure 6, between 9 and 11 on the horizontal axis, the difference between the resistance value of a specific cell and the average resistance value of all cells is greater than or equal to a predetermined value, but the number of consecutive detections is less than a certain number, so the repair necessity determination unit 62A can determine that cell repair is unnecessary. On the other hand, in Figure 6, between 1 and 6 on the horizontal axis, the difference between the resistance value of a specific cell and the average resistance value of all cells is greater than or equal to a predetermined value, and the number of consecutive detections is greater than or equal to a predetermined number, so the repair necessity determination unit 62A can determine that cell repair is necessary. The specific values ​​for the difference in resistance and the number of consecutive cycles used to determine whether repair is necessary can be appropriately set by a person skilled in the art.

[0047] Next, as another example of the cell repair necessity process step St2, an example of determining whether repair is necessary based on cell capacity information will be explained using Figure 7. In Figure 7, the horizontal axis shows the cell capacity value acquisition timing, and the vertical axis shows the cell's full charge capacity (Ah). Here, the cell capacity value acquisition timing may be a predetermined timing, for example, it may be the acquisition of resistance values ​​at predetermined time intervals. Alternatively, the cell capacity value acquisition timing may be when the SOC change exceeds a predetermined value during one run of the vehicle 1. Furthermore, the cell capacity value acquisition timing may be when the SOC rises above a predetermined value during a single charge. In Figure 7, the more recent these cell capacity value acquisition timings are displayed, the further to the right they are on the horizontal axis. That is, 1 on the horizontal axis is the most recent data, and 6 is the oldest data displayed. On the other hand, on the vertical axis, the average capacity of all cells included in the battery device 90 is shown with ○, and the capacity value of any cell acquired at the same time is shown with ▲.

[0048] As shown in Figure 7, the repair necessity determination unit 62A can determine that cell repair is necessary if the deviation from the average value of all cells is greater than or equal to a predetermined value and the number of consecutive detections is greater than or equal to a predetermined number. For example, in Figure 7, when the horizontal axis is 4 or 6, the difference between the capacity of the specific cell and the average capacity of all cells is less than a predetermined value, so the repair necessity determination unit 62A can determine that cell repair is unnecessary. Also, in Figure 7, when the horizontal axis is 5, the difference between the capacity of the specific cell and the average capacity of all cells is greater than or equal to a predetermined value, but the number of consecutive detections is less than a certain number, so the repair necessity determination unit 62A can determine that cell repair is unnecessary. On the other hand, in Figure 7, when the horizontal axis is 1 to 3, the difference between the capacity of the specific cell and the average capacity of all cells is greater than or equal to a predetermined value, and the number of consecutive detections is greater than or equal to a predetermined number, so the repair necessity determination unit 62A can determine that cell repair is necessary. Here, the specific values ​​of the difference in capacity values ​​and the number of consecutive detections used to determine whether repair is necessary can be appropriately set by a person skilled in the art.

[0049] The above describes examples of determining whether repair is necessary based on cell resistance information and cell capacitance information, but the means for determining whether repair is necessary are not limited to these. That is, the repair necessity determination unit 62A may determine whether cell repair is necessary based on both cell resistance information and cell capacitance information. The repair necessity determination unit 62A may also determine whether cell repair is necessary by combining cell resistance information or cell capacitance information with appropriately known information. Furthermore, the repair necessity determination unit 62A may determine whether cell repair is necessary based on cell repair period information including information on past repair times in the cell, or cell charge / discharge amount information including the charge / discharge amount in the cell within a predetermined period, instead of, or in combination with, cell resistance information or cell capacitance information.

[0050] Next, an example of the solid electrolyte heating process (step St6) is described below. In the heating process, the heating control unit 62B performs a heating treatment of the solid electrolyte on cells that have been determined to require cell repair in the cell repair necessity determination process. More specifically, the heating control unit 62B drives the discharge circuit 92 to supply a current that dissolves the solid electrolyte. At this time, the current value for dissolving the solid electrolyte may be adjusted in advance by setting a current limiting resistor in the discharge circuit 92 so as not to exceed the maximum allowable current value of the battery device 90. Furthermore, the timing for ending the energization in the heating process can be determined by pre-setting the time required to dissolve the solid electrolyte, or by detecting that the cell voltage has reached the lower allowable limit.

[0051] The recrystallization process (step St7) is described below. In the recrystallization process, the solid electrolyte dissolved in the heating process is recrystallized by cooling. More specifically, in the recrystallization process, as the battery temperature gradually decreases after the energization of the heating process ends, the crystalline solid electrolyte recrystallizes as the temperature decreases. The dissolved solid electrolyte flows into the cracks between the electrode active material and the solid electrolyte during the heating process, and these cracks are sealed by the solid electrolyte during the recrystallization process, thus improving battery performance.

[0052] Furthermore, the recrystallization process may include a cooling control step for controlling the temperature during the cooling process of the solid electrolyte. More specifically, the cooling control step may be a step in which, in the control of the heating control unit 62B, a smaller current is passed from the discharge circuit 92 than that of the heating step described above, thereby slowing down the recrystallization rate of the solid electrolyte (slowly cooling the dissolved solid electrolyte).

[0053] Furthermore, a regulating discharge step may be included after the recrystallization step, in which a discharge is performed on the cells that have undergone the heating and recrystallization steps described above, and the response voltage is checked. The discharge in this regulating discharge step may be performed by a known method as appropriate. In addition, known cell balance control may be performed on the cells that have undergone the recrystallization step described above by the battery management circuit 91.

[0054] <Second Embodiment> Next, a second embodiment of the present disclosure will be described. The second embodiment differs from the first embodiment described above in that the battery device 90 does not include a discharge circuit 92. For this reason, components similar to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0055] (Battery Device Configuration) Figure 8 is a schematic diagram showing an example of the configuration of a battery device 902 according to the second embodiment. As shown in Figure 8, the battery device 902 is equipped with a connector C that can be connected to an external charge / discharge heating device M. The connector C is electrically connected to the current collectors of the cells included in the battery device 902. With this configuration, the battery device can be repaired without having a discharge circuit corresponding to each cell, and miniaturization of the battery device and cost reduction can be expected.

[0056] Figure 9 is a flowchart showing an example of a battery repair method performed by the battery device 902 according to the second embodiment. As shown in Figure 9, in the battery repair method according to the second embodiment, the process may be started at a preset timing. For example, the process may be set to start when the vehicle running time exceeds a predetermined value, or when the accumulated current in the battery device exceeds a predetermined value.

[0057] In other words, in this second embodiment, the repair necessity determination unit 62A determines whether the cell 930 needs to be repaired (step St101). If it is determined that repair is necessary (Yes in step St102), a display to that effect is shown on the display device 50 or the like (step St103). This display may be a warning to the driver of the vehicle 1 prompting them to repair the cell 930. In the second embodiment, the determination of whether the cell needs to be repaired may be made based on cell information including cell resistance value information and cell capacitance information, as in the first embodiment described above. If it is determined that repair is not necessary (No in step St102), the series of processes may be terminated.

[0058] Next, the vehicle's connector C is connected to the external charge / discharge heating device M, and a current value sufficient to dissolve the solid electrolyte flows, thereby executing the heating process (step St104). In the heating process of this second embodiment, the discharge process and the charging process for the cells may be repeated. That is, the external charge / discharge heating device M may have both a discharge function and a charging function for the cells. In the heating process, the cells are energized so that charging and discharging have the same current capacity, thereby suppressing variations in the remaining capacity of the multiple cells contained in the battery device 902. Also, in the heating process, charging and discharging are switched so as not to exceed the upper and lower voltage limits of the battery device 902, thereby ensuring the energizing time necessary to dissolve the solid electrolyte while avoiding failure of the battery device 902. The current value Im for dissolving the solid electrolyte in the heating process can be set to less than the maximum allowable current value of the battery device 902. Also, the cell voltage Vtcd for switching from charging to discharging can be set to less than the maximum allowable cell voltage value. Furthermore, the cell voltage Vtdc for switching from discharging to charging can be set to greater than the minimum allowable cell voltage value. During the heating process, the energizing time may be adjusted as appropriate according to the battery temperature of the battery device 902.

[0059] In the recrystallization step (step St105), the molten solid electrolyte is recrystallized by cooling. Similar to the first embodiment described above, the recrystallization step may include a cooling control step to slow down the recrystallization rate of the solid electrolyte. After the recrystallization step, the series of processes is completed (END).

[0060] [Supplement] The battery repair method and battery control device illustrated in the above embodiments were described using a battery mounted on a vehicle as an example. However, they are not limited to this and can also be applied to stationary batteries or to mobile objects other than vehicles, such as airplanes.

[0061] Furthermore, the technology disclosed herein can also be realized as a vehicle equipped with the battery control device described in the above embodiment, a battery repair method using the battery control device, a computer program that causes a computer to function as the above-mentioned battery control device, and a non-temporary tangible recording medium on which the computer program is recorded.

[0062] 1...Vehicle 60...Control device 62...Processing device 62A...Repair necessity determination unit 62B...Heating control unit 90, 902...Battery device 930...Cell

Claims

1. A battery repair method comprising: a repair necessity determination step of determining whether a battery cell needs to be repaired based on cell information in a battery cell containing a solid electrolyte; a heating step of applying heat to the solid electrolyte at a temperature above its dissolution temperature if it is determined in the repair necessity determination step that the battery cell needs to be repaired; and a recrystallization step of recrystallizing the solid electrolyte dissolved in the heating step by cooling.

2. The battery repair method according to claim 1, wherein the cell information includes at least one of: cell resistance information including the resistance value of the battery cell; cell capacity information including the capacity value of the battery cell; cell repair period information including information on past repair times for the battery cell; and cell charge / discharge amount information including the charge / discharge amount for the battery cell within a predetermined period.

3. The battery repair method according to claim 1 or 2, further comprising a regulating discharge step of discharging the battery cell after the recrystallization step and confirming the response voltage at that time.

4. The battery repair method according to claim 1 or 2, further comprising a cooling control step for controlling the temperature during the cooling process of the solid electrolyte in the recrystallization step.

5. A battery control device for controlling a battery including a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, comprising: a repair necessity determination unit that determines whether or not a battery cell needs to be repaired based on cell information in the battery cell including the solid electrolyte layer; and a heating control unit that, based on the determination of the repair necessity determination unit, applies heat to the solid electrolyte contained in the solid electrolyte layer at a temperature above its dissolution temperature, wherein the heating control unit dissolves the solid electrolyte by applying an electric current between the positive electrode layer and the negative electrode layer.

6. The battery control device according to claim 5, wherein the cell information includes at least one of cell resistance information including the resistance value of the battery cell, cell capacity information including the capacity value of the battery cell, cell repair period information including information on past repair times in the battery cell, and cell charge / discharge amount information including the charge / discharge amount in the battery cell within a predetermined period.

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