Battery System

Abstract

To suppress deterioration of durability of an exterior package of a cell.SOLUTION: An ECU performs processing including the steps for: determining whether or not a charge / discharge control is being executed (S100); if it is determined that the charge / discharge control is being executed (YES at S100), obtaining temperature of a terminal part (S102); setting a limit value Win of charged power and a limit value Wout of discharged power (S104); and executing the charge / discharge control by using the limit value Win of the charged power after setting and the limit value Wout of the discharged power after setting (S106).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a battery system. [Background technology]

[0002] Known secondary batteries include, for example, all-solid-state batteries that use solid electrolytes. The exterior of a cell of an all-solid-state battery may be constructed by covering it with, for example, a laminate film having a heat-sealed seal. Regarding a cell covered with such a laminate film, for example, Japanese Patent Application Laid-Open No. 2021-114373 (Patent Document 1) discloses a technology that calculates moisture permeability based on the temperature of the seal and, if the moisture permeability is equal to or greater than a threshold, cools the seal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-114373 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the laminate film covering the cells as described above is not limited to being affected by moisture penetration, but may also be affected by heat generated by the cell or heat received from adjacent cells. If the temperature of the cell terminals rises due to heat generation or heat reception, this may affect the durability of the laminate film as an exterior that is in close contact with the terminals.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a battery system that suppresses deterioration in the durability of the exterior of the cells. [Means for solving the problem]

[0006] According to an aspect of the present disclosure, there is provided a battery system including an all-solid-state battery, an acquisition device that acquires temperature information about the temperatures of terminals of the all-solid-state battery, and a control device that controls transmission power transmitted between the all-solid-state battery and an electrical device, wherein the control device sets an upper limit value for the magnitude of the transmission power using the temperature information acquired by the acquisition device.

[0007] In this way, the upper limit can be set according to the temperature of the terminal, for example, by setting a low upper limit when the terminal is hot. Therefore, by setting a low upper limit, it is possible to suppress an increase in the amount of Joule heat generated in the terminal. This suppresses the rise in the temperature of the terminal and the effect on the durability of the laminate film.

[0008] In one embodiment, the acquisition device includes a temperature sensor provided at the terminal for detecting a temperature of the terminal, and the control device sets the upper limit value so that the value is reduced when the temperature of the terminal detected by the temperature sensor is high compared to when the temperature of the terminal is low.

[0009] In this way, the upper limit can be set low when the terminal is at a high temperature, thereby suppressing the increase in Joule heat generated in the terminal, thereby suppressing the increase in terminal temperature and the effect on the durability of the laminate film.

[0010] In yet another embodiment, the all-solid-state battery includes a plurality of cells. The acquisition device includes at least one of a thermistor provided at a terminal of at least one of the plurality of cells, a surface pressure sensor provided between the plurality of cells, a temperature sensor provided in each of the plurality of cells, and a detection device for detecting resistance values of the plurality of cells. The control device estimates the temperature of the terminals using the temperature information acquired by the acquisition device, and sets an upper limit value so that, when the estimated terminal temperature is high, the value is reduced compared to when the terminal temperature is low.

[0011] In this way, the temperature of the terminal can be estimated with high accuracy using temperature information acquired by a thermistor, a surface pressure sensor, a temperature sensor, or a detection device for detecting resistance values.

[0012] In yet another embodiment, the all-solid-state battery further includes a bus bar connecting the plurality of cells. The battery system further includes a current sensor detecting a current flowing through the bus bar. The control device estimates the temperature of the terminals using the detection result of the current sensor in addition to the temperature information acquired by the acquisition device.

[0013] In this way, the temperature of the cell terminals can be estimated with high accuracy by using the current value detected by the current sensor in addition to the temperature information acquired by the acquisition device.

[0014] Furthermore, in some embodiments, the cell of the all-solid-state battery is covered with a laminate film.

[0015] In this way, the temperature rise of the cell terminals can be suppressed, thereby suppressing the influence on the durability of the laminate film. [Effects of the Invention]

[0016] According to the present disclosure, it is possible to provide a battery system that suppresses deterioration in the durability of the exterior of the cell. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram showing an example of the configuration of a vehicle equipped with a battery system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a battery pack. [Figure 3] 4 is a flowchart illustrating an example of processing executed by an ECU. [Figure 4] FIG. 10 is a diagram illustrating an example of a map showing the relationship between temperature and a limit value. [Figure 5]10A and 10B are diagrams illustrating an example of the configuration of a battery pack according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0019] In the following, a case where a battery system 90 according to this embodiment is mounted on an electric vehicle (hereinafter referred to as a vehicle) 1 will be described as an example.

[0020] FIG. 1 is a diagram showing an example of the configuration of a vehicle 1 equipped with a battery system 90 according to this embodiment. As shown in FIG. 1, the vehicle 1 includes a motor generator (MG) 10, a power transmission gear 20, drive wheels 30, a power control unit (PCU) 40, a system main relay (SMR) 50, a charging relay (hereinafter referred to as a CHR) 60, a charging device 70, an inlet 80, a battery pack 100, and an electronic control unit (ECU) 300. The battery system 90 according to this embodiment is composed of the PCU 40, the charging device 70, the battery pack 100, and the ECU 300. The battery system 90 may further include the SMR 50 and the CHR 60.

[0021] The MG 10 is, for example, a three-phase AC rotating electric machine that functions as both an electric motor (motor) and a generator. The output torque of the MG 10 is transmitted to the drive wheels 30 via a power transmission gear 20 that includes a reduction gear, a differential gear, and the like.

[0022] When braking the vehicle 1, the MG 10 is driven by the drive wheels 30, and the MG 10 operates as a generator. This allows the MG 10 to function as a braking device that performs regenerative braking, converting the kinetic energy of the vehicle 1 into electric power. The regenerative power generated by the regenerative braking force in the MG 10 is stored in the battery pack 100.

[0023] PCU 40 is a power conversion device that converts power bidirectionally between MG 10 and battery pack 100. PCU 40 includes an inverter and a converter that operate based on a control signal from ECU 300, for example.

[0024] The converter boosts the voltage supplied from the battery pack 100 and supplies the boosted voltage to the inverter when the battery pack 100 is discharging. The inverter converts the DC power supplied from the converter into AC power to drive the MG 10.

[0025] On the other hand, the inverter converts AC power generated by the MG 10 into DC power and supplies it to the converter when charging the battery pack 100. The converter steps down the voltage supplied from the inverter to a voltage suitable for charging the battery pack 100 and supplies it to the battery pack 100.

[0026] Furthermore, PCU 40 suspends charging and discharging by stopping the operation of the inverter and converter based on a control signal from ECU 300. Note that PCU 40 may be configured without the converter.

[0027] The SMR 50 is electrically connected to a power line connecting the battery pack 100 and the PCU 40. When the SMR 50 is closed (i.e., in a conductive state) in response to a control signal from the ECU 300, power can be exchanged between the battery pack 100 and the PCU 40. On the other hand, when the SMR 50 is opened (i.e., in a cut-off state) in response to a control signal from the ECU 300, the electrical connection between the battery pack 100 and the PCU 40 is cut off.

[0028] The CHR 60 is electrically connected between the battery pack 100 and the charging device 70. When the CHR 60 is closed (i.e., in a conductive state) in response to a control signal from the ECU 300 and a connector 150 of a system power supply 160, which is an external power source, is attached to an inlet 80, which will be described later, the battery pack 100 can be charged using the charging device 70. On the other hand, when the CHR 60 is opened (i.e., in a cut-off state) in response to a control signal from the ECU 300, the electrical connection between the battery pack 100 and the charging device 70 is cut off.

[0029] The inlet 80 is provided on the exterior of the vehicle 1 together with a cover such as a lid (not shown). The inlet 80 has a shape that allows a connector 150, which will be described later, to be mechanically connected. Both the inlet 80 and the connector 150 have built-in contacts, and when the connector 150 is attached to the inlet 80, the contacts come into contact with each other, and the inlet 80 and the connector 150 are electrically connected.

[0030] Connector 150 is connected to system power supply 160 via charging cable 170. Therefore, when connector 150 is connected to inlet 80 of vehicle 1, power from system power supply 160 can be supplied to vehicle 1 via charging cable 170, connector 150, and inlet 80.

[0031] The charging device 70 is electrically connected to the battery pack 100 via the CHR 60 and is also electrically connected to the inlet 80. In response to a control signal from the ECU 300, the charging device 70 converts AC power supplied from the system power supply 160 into DC power and outputs the DC power to the battery pack 100. For example, when a connector 150 is attached to the inlet 80, the charging device 70 charges the battery pack 100 using the power supplied from the system power supply 160. Hereinafter, such charging using the system power supply 160 may be referred to as "external charging."

[0032] The battery pack 100 is a power storage device that stores power for driving the MG 10. The battery pack 100 is a rechargeable DC power supply, and is configured, for example, by connecting a plurality of cells 110 in series. The cells 110 are secondary batteries that use a solid electrolyte for the movement of ions between the positive electrode and the negative electrode, and are all-solid-state batteries whose constituent members are all-solid-state. As materials for composing the cells 110, any known materials for composing all-solid-state batteries may be used, as will be described later.

[0033] A voltage sensor 210, a current sensor 220, and a terminal temperature sensor 230 are connected to ECU 300.

[0034] The voltage sensor 210 detects the voltage Vb between the terminals of each of the multiple cells 110. The current sensor 220 detects the current Ib input to and output from the battery pack 100. The terminal temperature sensor 230 is provided at the positive or negative terminal of each of the multiple cells 110, and detects the temperature Tb of the provided terminal (hereinafter referred to as terminal temperature). Each sensor outputs its detection result to the ECU 300.

[0035] ECU 300 includes a CPU (Central Processing Unit) 301 and memory (ROM (Read Only Memory) and RAM (Random Access Memory)) 302. ECU 300 controls each device (for example, PCU 40 or charging device 70) based on signals received from each sensor and information such as maps and programs stored in memory 302, so that vehicle 1 is in a desired state.

[0036] The amount of stored power in the battery pack 100 is generally managed by the SOC, which indicates the ratio of the current amount of stored power to the fully charged capacity as a percentage. The ECU 300 has a function of successively calculating the SOC of the battery pack 100 based on the values detected by the voltage sensor 210, the current sensor 220, and the terminal temperature sensor 230. As a method for calculating the SOC, various known methods can be used, such as a method based on current value integration (coulomb counting) or a method based on open circuit voltage (OCV) estimation.

[0037] While vehicle 1 is in operation, battery pack 100 is charged or discharged by regenerative power or discharge power from MG 10. ECU 300 controls the output of MG 10 so that MG 10 outputs power for generating the vehicle driving force (required driving force set according to the accelerator opening) or braking force (required deceleration force set according to the brake pedal depression amount and vehicle speed) requested by the driver.

[0038] On the other hand, when the vehicle 1 is stopped and the connector 150 is connected to the inlet 80, the ECU 300 turns on the CHR 60 and operates the charging device 70 to charge the battery pack 100 using power from the system power supply 160.

[0039] For example, the ECU 300 continues charging until the SOC of the battery pack 100 reaches a preset upper limit value (or a value set according to the deterioration state of the battery pack 100), and terminates charging when the SOC of the battery pack 100 reaches the upper limit value.

[0040] The ECU 300 sets a limit value (hereinafter referred to as Win) of the charging power when charging the battery pack 100 depending on, for example, the temperature of the battery pack 100, and controls the PCU 40 and the charging device 70 so that the battery pack 100 is not charged with charging power that exceeds the limit value Win. Furthermore, the ECU 300 sets a limit value (hereinafter referred to as Wout) of the discharging power when discharging the battery pack 100 depending on, for example, the temperature of the battery pack 100, and controls the PCU 40 so that the battery pack 100 is not discharged with discharging power that exceeds the limit value Wout.

[0041] The battery pack 100 configured as described above and mounted on the vehicle 1 includes a plurality of cells 110. The plurality of cells 110 are configured to be covered with a laminate or the like as an exterior covering, for example.

[0042] Fig. 2 is a diagram showing an example of the configuration of a battery pack 100. As shown in Fig. 2, the battery pack 100 includes a plurality of cells 110, each including a positive terminal 102, a negative terminal 104, and an exterior laminate film 118, a plurality of bus bars 106 that connect the positive terminal 102 of one of the plurality of cells 110 to the negative terminal 104 of the cell 110 adjacent to the positive terminal 102, a battery case 112 that houses a stack formed by stacking a predetermined number of the plurality of cells (seven in Fig. 2), and a bus bar 108 that has one end connected to the terminal negative terminal 104.

[0043] Each of the plurality of cells 110 includes an electrode assembly including a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer.

[0044] The solid electrolyte material contained in the solid electrolyte layer is not particularly limited as long as it is a material that can be used as a solid electrolyte in an all-solid-state battery. Examples of the solid electrolyte material include a sulfide-based amorphous solid electrolyte and an oxide-based amorphous solid electrolyte.

[0045] The active materials contained in the positive electrode layer and the negative electrode layer are not particularly limited as long as they are usable as electrode active materials for all-solid-state batteries, and examples of the active materials include nickel-cobalt-manganese oxide (NCM), nickel-cobalt-aluminum-lithium oxide (NCA), lithium cobalt oxide (LCO), (lithium titanate) LTO, and lithium manganese oxide (LMO).

[0046] The positive electrode layer and the negative electrode layer may contain conductive additive particles, such as graphite or carbon black.

[0047] The materials for the positive electrode current collector and the negative electrode current collector are not particularly limited as long as they are conductive and function as positive electrode current collector and negative electrode current collector, respectively, and examples thereof include SUS (Steel Use Stainless Steel), aluminum, copper, nickel, iron, titanium, and carbon. Furthermore, the shapes of the positive electrode current collector and the negative electrode current collector include, for example, foil, plate, mesh, etc. A positive electrode terminal is connected to the positive electrode current collector. A negative electrode terminal is connected to the negative electrode current collector.

[0048] The electrode assembly includes a first element having a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer stacked in this order, and a second element having a negative electrode current collector layer shared by the first element and the second element stacked in the reverse order. The first and second elements are alternately stacked. The negative electrode current collector layers of the multiple elements are connected to the negative electrode terminal 104 of the cell 110, and the positive electrode current collector layers of the multiple elements are connected to the positive electrode terminal 102 of the cell 110. The positive electrode terminal 102 and the negative electrode terminal 104 of the cell 110 are arranged in the front-to-rear direction of the page in FIG. 2. The positive electrode terminal 102 and the negative electrode terminal 104 of the adjacent cell 110 are stacked so that the positive electrode terminal 102 and the negative electrode terminal 104 of the adjacent cell 110 face each other. FIG. 2 shows a cross section including either the positive electrode terminal 102 or the negative electrode terminal 104 of the multiple cells 110.

[0049] 2, the electrode body of each of the multiple cells 110 is covered as an exterior with a laminate film 118. The laminate film 118 is in close contact with the terminal portions (positive electrode terminal 102 and negative electrode terminal 104) of the electrode body, thereby preventing dust and water from entering the interior.

[0050] In the battery pack 100 configured as described above, the laminate film 118 covering the electrode bodies of the plurality of cells 110 described above may be affected by heat received from adjacent cells 110 via the bus bar 106. In other words, if the temperature of the terminals of the cells 110 increases via the bus bar 106, this may affect the durability of the laminate film 118 that is in close contact with the terminals.

[0051] Therefore, in this embodiment, the ECU 300 sets an upper limit value for the magnitude of the transmission power transmitted between the battery pack 100 and an electrical device (for example, the PCU 40 or the charging device 70) using temperature information about the temperatures of the terminal portions of the multiple cells 110 that are all-solid-state batteries.

[0052] In this way, the upper limit value can be set in accordance with the temperature of the terminal portion, for example, by setting a low upper limit value when the terminal portion of one of the multiple cells 110 is at a high temperature, thereby preventing the temperature of the terminal portion from affecting the durability of the laminate film 118, which is the exterior.

[0053] An example of processing executed by ECU 300 will be described below with reference to Fig. 3. Fig. 3 is a flowchart showing an example of processing executed by ECU 300. A series of processing shown in this flowchart is repeatedly executed by ECU 300 at predetermined intervals while vehicle 1 is being driven or while charging using an external power source.

[0054] In step (hereinafter, step will be abbreviated as S) 100, ECU 300 determines whether charge / discharge control is being executed. ECU 300 determines that charge / discharge control is being executed when either charge control or discharge control is being executed on battery pack 100. ECU 300 may determine that either charge control or discharge control is being executed when the magnitude of the current detected by current sensor 220 is equal to or greater than a predetermined value. Alternatively, ECU 300 may determine that either charge control or discharge control is being executed when, after outputting a control signal to PCU 40 for executing either charge control or discharge control, ECU 300 has not output a control signal to PCU 40 for stopping the control. Alternatively, ECU 300 may determine that either charge control or discharge control is being executed when a flag that is turned on when either charge control or discharge control is executed and turned off when the control is stopped is on. If it is determined that charge / discharge control is being executed (YES in S100), the process proceeds to S102.

[0055] In S102, ECU 300 obtains the temperature of the terminal portion of each of the plurality of cells 110 using terminal temperature sensor 230.

[0056] In S104, ECU 300 sets a limit value Win of charging power and a limit value Wout of discharging power.

[0057] Specifically, the ECU 300, for example, identifies the maximum temperature (hereinafter referred to as the maximum temperature) among the temperatures of the terminal portions of the plurality of cells 110, and sets the limit value Win of the charging power and the limit value Wout of the discharging power corresponding to the identified maximum temperature. Note that the ECU 300 may set the limit values Win and Wout using the average value of the temperatures of the terminal portions of the plurality of cells instead of the maximum temperature.

[0058] ECU 300 sets the limit value Win of charging power and the limit value Wout of discharging power from the maximum temperature identified using, for example, a map showing the relationship between temperature and limit values. FIG. 4 is a diagram showing an example of a map showing the relationship between temperature and limit values. The horizontal axis of FIG. 4 represents the temperature of the terminal portion. The vertical axis of FIG. 4 represents the limit value Win of charging power (negative direction) and the limit value Wout of discharging power (positive direction). LN1 in FIG. 4 represents the change in the limit value Wout of discharging power with respect to the change in temperature of the terminal portion. LN2 in FIG. 4 represents the change in the limit value Win of charging power with respect to the change in temperature of the terminal portion.

[0059] As shown in LN1 of Fig. 4, the relationship between the temperature of the terminal part and the limit value Wout of the discharge power is such that the limit value Wout of the discharge power is set to a predetermined value Wout(1) until the temperature of the terminal part reaches a predetermined first temperature Tb(0). Then, the relationship between the temperature of the terminal part and the limit value Wout of the discharge power is such that when the temperature of the terminal part reaches or exceeds the first temperature Tb(0), the limit value Wout of the discharge power is set to a smaller value as the temperature of the terminal part increases. In other words, when the temperature of the terminal part is high, the limit value Wout of the discharge power is set to a smaller value than when the temperature of the terminal part is low.

[0060] The first temperature Tb(0) is adapted, for example, through experiments, etc. Furthermore, the relationship between the temperature of the terminal part and the limit value Wout of the discharge power is such that when the temperature of the terminal part becomes equal to or higher than a predetermined second temperature Tb(1), the limit value Wout of the discharge power is set to zero.

[0061] As shown in LN2 of FIG. 4, the relationship between the terminal temperature and the limit value Win of the charging power is such that a predetermined value Win(1) is set as the limit value Win of the charging power until the temperature of the terminal reaches a first temperature Tb(0). The relationship between the terminal temperature and the limit value Win of the charging power is such that, when the temperature of the terminal reaches or exceeds the first temperature Tb(0), the limit value Win of the charging power is set to a smaller value as the temperature of the terminal increases. That is, when the temperature of the terminal is high, the limit value Win of the charging power is set to a smaller value compared to when the temperature of the terminal is low. Furthermore, the relationship between the terminal temperature and the limit value Win of the charging power is such that, when the temperature of the terminal reaches or exceeds a second temperature Tb(1), the limit value Win of the charging power is set to zero. The relationships between the terminal temperature and the limit values shown in LN1 and LN2 of FIG. 4 are merely examples, and are not limited to the relationship shown in FIG. 4.

[0062] Therefore, for example, when ECU 300 identifies that the maximum temperature among the plurality of cells 110 is Tb(1), it sets Wout(0) as the limit value Wout of the discharge power and sets Win(0) as the limit value Win of the charge power. Thereafter, the process proceeds to S106.

[0063] In S106, ECU 300 executes charge / discharge control using the set limit value Win of charge power and the set limit value Wout of discharge power.

[0064] For example, while the battery pack 100 is being charged, the ECU 300 controls the current supplied to the battery pack 100 so that the magnitude of the charging power does not exceed the limit value Win. For example, when the battery pack 100 is charged using an external power supply, the ECU 300 performs the above-described current control using the charging device 70. Furthermore, for example, when the battery pack 100 is charged while driving, the ECU 300 performs the above-described current control using the PCU 40.

[0065] On the other hand, while the battery pack 100 is discharging, the ECU 300 controls the current supplied from the battery pack so that the magnitude of the discharge power does not exceed the magnitude of the limit value Wout. For example, when the battery pack 100 is discharged during driving, the ECU 300 executes the above-described current control using the PCU 40.

[0066] An example of the operation of the battery system 90 based on the above-described structure and flowchart will now be described.

[0067] For example, assume that the battery pack 100 is being charged using an external power source. When charge / discharge control is being executed (YES in S100), the detection results of the terminal temperature sensors 230 provided in each of the multiple cells 110 are obtained to acquire the terminal temperatures of each of the multiple cells 110 (S102).

[0068] The maximum temperature among the acquired terminal temperatures is identified, and a limit value Win of the charging power and a limit value Wout of the discharging power are set based on the identified maximum temperature and the relationship between the terminal temperatures and the limit values shown in FIG. 4 (S104). Then, charge / discharge control is performed using the set limit value Win of the charging power and the set limit value Wout of the discharging power (S106). Therefore, while the battery pack 100 is being charged, the current supplied to the battery pack 100 is controlled using the charging device 70 so that the magnitude of the charging power does not exceed the set limit value Win of the charging power. As a result, heat generation in each of the multiple cells 110 is suppressed.

[0069] As described above, according to the battery system 90 of this embodiment, the upper limit values (limit values Win and Wout) can be set in accordance with the temperature of the terminal portions, for example, by setting a low upper limit value when the terminal portions are at high temperatures, thereby preventing the temperature of the terminal portions from affecting the laminate film 118. Therefore, it is possible to provide a battery system that prevents deterioration in the durability of the exterior of the cells.

[0070] Furthermore, each limit value is set so that the magnitude decreases as the temperature of the terminal portion detected by the terminal temperature sensor 230 increases, so that the influence of the temperature of the terminal on the laminate film 118 can be suppressed.

[0071] Modifications will be described below. In the above-described embodiment, it has been described that the charging power limit value Win and the discharging power limit value Wout are set using the temperature of the terminal portion acquired by the terminal temperature sensor 230 provided at either the positive terminal or the negative terminal of the cell 110, but this is not particularly limited to acquiring the temperature of the terminal portion using the terminal temperature sensor 230.

[0072] For example, the maximum temperature among the temperatures of the plurality of cells 110 may be obtained using the detection result of the resistance value of a thermistor provided at at least one terminal portion of the plurality of cells 110. The thermistors may be provided at multiple locations among the plurality of cells 110 constituting the battery pack 100 where the temperature is higher than the other cells.

[0073] Alternatively, for example, the maximum temperature among the temperatures of the plurality of cells 110 may be obtained using the detection results of temperature sensors provided at locations other than the terminal portions of the plurality of cells 110.

[0074] Alternatively, for example, the maximum temperature among the temperatures of the plurality of cells 110 may be obtained using the detection results of a surface pressure sensor provided between at least any two of the plurality of cells 110. FIG. 5 is a diagram illustrating an example of the configuration of a battery pack 100 according to a modified example. As shown in FIG. 5, a surface pressure sensor 240 is provided to cover the entire surface in the stacking direction between each of the plurality of cells 110. The surface pressure sensor 240 includes a plurality of surface pressure measurement points, detects pressure acting at the measurement points, and transmits information indicating the detected pressure and information indicating the positions of the measurement points to the ECU 300. The ECU 300 may estimate the expansion amount of the plurality of cells 110 using the received pressure, estimate the temperature of the terminal portion from the estimated expansion amount, and obtain the maximum temperature among the temperatures of the plurality of cells 110.

[0075] Alternatively, the ECU 300 may detect the resistance value (internal resistance) of each of the multiple cells 110. The ECU 300 may detect the resistance value of each of the multiple cells 110, for example, by detecting the voltage and current applied to each of the multiple cells 110. The ECU 300 may estimate the temperature of each of the multiple cells 110 using the detected resistance value, and obtain the maximum temperature of each of the multiple cells 110 using the estimated temperature.

[0076] By using the temperature information on the temperature of the terminal portion as described above, the temperature of the terminal portion of the cell 110 can be estimated with high accuracy.

[0077] Furthermore, in addition to the temperature information obtained using the above-mentioned thermistor, surface pressure sensor, temperature sensor, or detection device that detects resistance values, the temperature of the terminal portion may be estimated using a current sensor 220 that detects the value of the current flowing through the bus bar 106 that connects each of the multiple cells 110.

[0078] For example, ECU 300 may correct the temperature of the terminal portion of each cell acquired using the temperature information using a current value indicated by the detection result of current sensor 220. For example, ECU 300 may correct the temperature of the terminal portion so that the temperature increases as the current value of current sensor 220 increases. Because heat (Joule heat) generated at the terminal portion also contributes to the current flowing through the bus bar, the temperature of the terminal portion can be estimated with high accuracy by estimating the temperature of the terminal portion using a current value in addition to the temperature information as described above.

[0079] The above-described modifications may be implemented in whole or in part in appropriate combination. The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0080] 1 Vehicle, 10 MG, 20 Power transmission gear, 30 Drive wheels, 40 PCU, 50 SMR, 60 CHR, 70 Charging device, 80 Inlet, 90 Battery system, 100 Battery pack, 102 Positive terminal, 104 Negative terminal, 106, 108 Bus bar, 110 Cell, 112 Battery case, 118 Laminate film, 150 Connector, 160 System power supply, 170 Charging cable, 210 Voltage sensor, 220 Current sensor, 230 Terminal temperature sensor, 240 Surface pressure sensor, 300 ECU, 301 CPU, 302 Memory.

Claims

1. A battery system, All-solid-state batteries and an acquisition device that acquires temperature information regarding the temperature of a terminal of the all-solid-state battery; a control device that controls transmission power transmitted between the all-solid-state battery and an electrical device; the control device sets an upper limit value for the magnitude of the transmission power using the temperature information acquired by the acquisition device; the all-solid-state battery includes a plurality of cells and a bus bar connecting the plurality of cells, the acquisition device includes at least one of a thermistor provided at at least one terminal of the plurality of cells, a surface pressure sensor provided between the plurality of cells, a temperature sensor provided in each of the plurality of cells, and a detection device for detecting resistance values of the plurality of cells; the control device estimates the temperature of the terminal using the temperature information acquired by the acquisition device, and when the estimated temperature of the terminal is high, sets the upper limit value so that the value is reduced compared to when the temperature of the terminal is low; the battery system further includes a current sensor that detects a current flowing through the bus bar; The control device estimates the temperature of the terminals using the temperature information acquired by the acquisition device as well as the detection result by the current sensor.

2. the acquisition device includes a temperature sensor provided in the terminal and detecting a temperature of the terminal; 2. The battery system according to claim 1, wherein the control device sets the upper limit value so that the value is smaller when the temperature of the terminal detected by the temperature sensor is high than when the temperature of the terminal is low.

3. The battery system according to claim 1 , wherein the cells of the all-solid-state battery have a laminate film as an exterior material.

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