vehicle

Abstract

This prevents an excessive rise in internal battery pressure caused by gas generated inside the battery when the vehicle is stopped. [Solution] When the power switch is operated and the vehicle is stopped, the battery ECU determines whether the battery temperature TB is above a predetermined value α and the battery state of charge (SOC) is above a predetermined value β (first state) (S11, S12). The time spent in the first state (affirmed in S11 and S12) is accumulated to calculate the cumulative time ΣT (S13). When the cumulative time ΣT is above a predetermined value s (affirmed in S14), the flag F is set to 1 (second state), and the cooling device is activated to cool the battery (S17). If the cooling device cannot be activated (negatively determined in S16), the battery is discharged. As the temperature TB and SOC decrease, the first state is exited, which suppresses the gas generated when the vehicle is stopped and prevents an excessive rise in battery internal pressure.

Description

Technical Field

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[0001] The present disclosure relates to a vehicle.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2018-98900 (Patent Document 1) discloses suppressing excessive increase in the internal pressure of a secondary battery capable of charging and discharging. In this Patent Document 1, based on the internal pressure and voltage of the battery, a limit value of the input power of the battery is set to suppress the gas generated inside the battery and suppress the increase in the internal pressure of the battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the increase in the internal pressure of the battery is suppressed by restricting the input power of the battery. However, when the start switch mounted on the vehicle is turned off and the vehicle stops, and in the system-off state, the charging and discharging of the battery stops. Therefore, in Patent Document 1, the gas generated inside the battery in the system-off state is not considered.

[0005] An object of the present disclosure is to suppress excessive increase in the internal pressure of the battery due to the gas generated inside the battery when the vehicle stops.

Means for Solving the Problems

[0006] The vehicle of this disclosure is a vehicle equipped with an externally rechargeable battery, a drive system that drives the vehicle using the power of the battery, a cooling device for cooling the battery, and a control device. The control device includes a determination means for determining whether the battery is in a first state in which the temperature of the battery is above a first predetermined temperature and the State of Charge (SOC) of the battery is above a first predetermined value when the power switch is operated and the drive system is stopped, and an accumulation means for accumulating the time when the battery is in the first state. When the control device enters a second state in which the accumulated time calculated by the accumulation means is above a set time, it discharges the battery.

[0007] In this configuration, the control device's determination means determines whether the battery is in a first state, where, when the power switch is operated and the drive system is stopped, the battery temperature is above a first predetermined temperature and the battery's SOC is above a first predetermined value. The first state is a state in which gas is easily generated inside the battery, even when the battery is not being charged or discharged. The integration means integrates the time spent in the first state. The accumulated time calculated by the integration means is approximately proportional to the amount of gas inside the battery and correlates with the magnitude of the battery's internal pressure. The second state, where the accumulated time is above a set time, is a state in which the battery's internal pressure is high.

[0008] The control device discharges the battery when it enters a second state, where the cumulative time exceeds a set time. Discharging the battery reduces the State of Charge (SOC). When the SOC falls below a first predetermined value, the device exits the first state, making it less likely for gas to be generated inside the battery, thus suppressing a further increase in the battery's internal pressure. Therefore, it is possible to suppress an excessive increase in the battery's internal pressure caused by gas generated inside the battery when the drive system is stopped (when the vehicle is stopped).

[0009] Preferably, the cooling device may cool the battery by a refrigeration cycle that operates using the battery's power. The control device may operate the refrigeration cycle to discharge the battery and cool it.

[0010] In this configuration, when the control device enters the second state, it activates the refrigeration cycle to discharge the battery and cool it. Discharge causes the State of Charge (SOC) to fall below a first predetermined value, and the battery is cooled, causing its temperature to fall below the first predetermined temperature. Therefore, the first state is exited due to the decrease in SOC and the decrease in battery temperature, making it less likely for gas to be generated inside the battery, and more preferably suppressing an excessive rise in internal battery pressure.

[0011] Preferably, when the control device reaches the second state, it stops discharging if the battery temperature is below a second predetermined temperature or if the SOC is below a second predetermined value. The control device may then proceed with discharging if the battery temperature is above the second predetermined temperature and the SOC is greater than the second predetermined value.

[0012] In this configuration, when the second state is reached, if the battery temperature is below a second predetermined temperature, or if the SOC is below a second predetermined value, discharge is stopped. The second predetermined temperature may be lower than the first predetermined temperature, or it may be the same as the first predetermined temperature. The second predetermined value may be smaller than the first predetermined value, or it may be the same as the first predetermined value. By stopping the discharge, an excessive decrease in SOC can be prevented, the operation of the cooling device is stopped, and an excessive decrease in the battery temperature can be prevented.

[0013] Then, when the battery temperature rises above the second predetermined temperature and the SOC (State of Charge) exceeds the second predetermined value, approaching a state where gas is easily generated inside the battery, discharge is performed again. This suppresses gas generation and prevents the internal pressure of the battery from rising excessively.

[0014] The vehicle of this disclosure is a vehicle equipped with an externally rechargeable battery, a drive system that drives the vehicle using the power of the battery, a cooling device for cooling the battery, and a control device. The control device includes a determination means for determining whether the battery is in a first state in which the temperature of the battery is above a first predetermined temperature and the state of charge (SOC) of the battery is above a first predetermined value when the power switch is operated and the drive system is stopped, and an integration means for accumulating the time when the first state is in place. When the control device enters a second state in which the accumulated time calculated by the integration means is above a set time, the control device cools the battery with the cooling device.

[0015] In this configuration, when the control device enters a second state where the cumulative time exceeds a set time, the cooling device cools the battery. Cooling the battery lowers its temperature. When the battery temperature falls below a first predetermined temperature, it exits the first state, making it less likely for gas to be generated inside the battery, thus suppressing a further increase in the battery's internal pressure. Therefore, it is possible to suppress an excessive increase in the battery's internal pressure caused by gas generated inside the battery when the drive system is stopped (when the vehicle is stopped).

[0016] Preferably, the battery is a battery pack consisting of multiple battery cells. Each battery cell is equipped with a pressure relief valve that opens when the internal pressure exceeds a predetermined pressure. The set time may be set to a value such that the internal pressure of the battery does not exceed the predetermined pressure due to the gas generated inside the battery cell.

[0017] In this configuration, the set time is set to a value that prevents the internal pressure of the battery from exceeding a predetermined pressure due to the gas generated inside the battery cell. When the drive system stops (when the vehicle stops), the generation of gas inside the battery can be suppressed before the internal pressure rises excessively due to the gas generated inside the battery and the pressure relief valve opens, thereby preventing the pressure relief valve from opening. [Effects of the Invention]

[0018] According to this disclosure, it is possible to suppress an excessive rise in internal battery pressure caused by gas generated inside the battery when the vehicle is stopped. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic configuration diagram of a vehicle according to the present embodiment. [Figure 2] This is a diagram for explaining an example of a cooling device. [Figure 3] This is a flowchart showing an example of stop-time battery control executed by a battery ECU. Embodiments for Carrying Out the Invention

[0020] 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 denoted by the same reference numerals, and the description thereof will not be repeated.

[0021] FIG. 1 is a schematic configuration diagram of a vehicle 1 according to the present embodiment. In this embodiment, the vehicle 1 is an electric vehicle, for example, a battery electric vehicle (BEV). 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 battery 100, a monitoring unit 200, a battery electronic control unit (ECU) 250, and a control ECU 300.

[0022] The MG 10 has functions as an electric motor and as a generator. The output torque of the MG 10 is transmitted to the drive wheels 30 via a power transmission gear 20 configured to include a reduction gear and a differential device.

[0023] When the vehicle 1 is braked, the drive wheels 30 drive the MG 10, and the MG 10 operates as a generator. The regenerative power generated by the regenerative braking force in the MG 10 is stored in the battery 100.

[0024] The PCU40 is a power converter that converts power bidirectionally between the MG10 and the battery 100. The PCU40 includes, for example, an inverter and a converter that operate based on control signals from the control ECU300 to drive the MG10. The MG10, PCU40, etc., constitute an example of the “drive system” of this disclosure.

[0025] The SMR50 is electrically connected to the power line connecting the battery 100 and the PCU 40. When the SMR50 is turned ON and conducting in response to a control signal from the control ECU 300, power can be exchanged between the battery 100 and the PCU 40. On the other hand, when the SMR50 is turned OFF and disconnected, the electrical connection between the battery 100 and the PCU 40 is disconnected.

[0026] Battery 100 stores power to drive MG10. Battery 100 is a secondary battery and is a battery pack composed of a plurality of individual cells 110. Each individual cell is, for example, a lithium-ion battery, which may be a nickel-metal hydride battery or a solid-state battery. Battery 100 corresponds to the “battery” in this disclosure.

[0027] The single cell 110 may be, for example, a rectangular cell 110a. In the rectangular cell 110a, an electrode body 112a is housed inside a case 111a made of a rectangular parallelepiped housing, and an electrolyte is sealed inside. Alternatively, the single cell 110 may be a laminated cell (pouch cell) 110b. In the laminated cell 110b, an electrode body 112b and an electrolyte are sealed inside a case 111b made of laminate film. Both the rectangular cell 110a and the laminated cell 110b are equipped with components such as a discharge valve (pressure relief valve) for releasing gas to the outside when the internal pressure of the battery rises due to gas generated inside the battery (inside the case), and a current interruption mechanism for interrupting the current when the battery overheats abnormally. The pressure relief valve opens when the internal pressure of the battery exceeds a predetermined pressure.

[0028] The monitoring unit 200 includes a voltage detection unit, a current sensor, and a temperature detection unit. The voltage detection unit detects the battery voltage VB. The current sensor detects the current IB that is input to and output from the battery 100. The temperature detection unit detects the temperature TB of the battery 100. The voltage VB, temperature TB, and current IB are input to the battery ECU 250. The battery ECU 250 calculates the State of Charge (SOC) of the battery 100. The SOC may be calculated, for example, by the Coulomb count method, the SOC-OCV (Open Circuit Voltage) characteristic, or a combination thereof. The voltage VB, temperature TB, current IB, and SOC are output from the battery ECU 250 to the control ECU 300. The battery ECU 250 corresponds to an example of a "control device" in this disclosure.

[0029] Vehicle 1 is equipped with a DC inlet 60 and an AC inlet 80, and the battery 100 can be charged (externally charged) from an external DC power supply 400 or an external AC power supply 500, or other charging equipment (EVSE: Electric Vehicle Supply Equipment) 2. When the connector 420 at the end of the charging cable 410 of the external DC power supply (EVSE) 400 is connected to the DC inlet 60, the charging relay 70 is controlled to the connected state, and external charging (rapid charging) of the battery 100 is performed.

[0030] When the connector 520 at the end of the charging cable 510 of the external AC power supply (EVSE) 500 is connected to the AC inlet 80, the onboard charger 130 converts the alternating current power supplied from the external AC power supply into direct current power. The direct current power output from the onboard charger 130 is supplied to the battery 100 via the charging relay 90, and external charging (normal charging) of the battery 100 is performed.

[0031] The control ECU 300 includes a CPU (Central Processing Unit) 301 and a memory 302. Based on signals received from the battery ECU 250, signals from various sensors (not shown) (e.g., accelerator opening signal, vehicle speed signal, etc.), and information such as maps and programs stored in the memory 302, the control ECU 300 controls each device so that the vehicle 1 reaches a desired state. The control ECU 300 controls the cooling system 800. The battery ECU 250 also includes a CPU and memory, similar to the control ECU 300.

[0032] The power switch (ignition switch) 350 is operated by the user. For example, if the user operates the power switch 350 while pressing the brake pedal (not shown), the control ECU 300 controls the SMR50 to turn ON (conductive state). When the SMR50 is ON, the PCU 40 enables the MG10 to be driven (the drive system is started), and vehicle 1 becomes drivable. If the user operates the power switch 350 while vehicle 1 is drivable, the SMR50 turns OFF (disconnected state), the PCU 40 etc (drive system) stops, and vehicle 1 comes to a stop.

[0033] The HMI (Human Machine Interface) device 700 includes an input device and a display device. The input device and display device may be a touch panel display.

[0034] Vehicle 1 is equipped with a cooling system 800. The cooling system 800 cools the battery 100. Figure 2 is a diagram illustrating an example of the cooling system 800. In this embodiment, the cooling system 800 consists of a thermal management circuit capable of cooling and heating the battery 100. The cooling system 800 (thermal management circuit) includes a thermal circuit S and a refrigeration cycle R.

[0035] The refrigeration cycle R circulates a refrigerant. The refrigeration cycle R includes a compressor R1 and a condenser R2. The high-pressure refrigerant discharged from the condenser R2 flows into the evaporator R3 via an electric expansion valve, and also flows into the chiller Ch via an electric expansion valve. The evaporator R3 is used as the cooling source for the air conditioning system of the vehicle 1. The chiller Ch exchanges heat with the heat transfer medium circulating in the heat circuit S, thereby cooling the heat transfer medium.

[0036] The thermal circuit S circulates a heat transfer medium. The thermal circuit S includes a three-way valve S1, a battery 100, a reserve tank (R / T), an SPU (Smart Power Unit), a PCU 40, an oil cooler (O / C), and pumps W1 and W2. When pump W1 is activated, ports P1 and P2 of the three-way valve S1 are connected, and the heat transfer medium cooled by the chiller Ch circulates through the battery 100, thereby cooling the battery 100. When pump W2 is activated, ports P2 and P3 of the three-way valve S1 are connected, and the heat transfer medium heated by the waste heat from the SPU, PCU 40, and O / C circulates through the battery 100, thereby heating the battery 100. An electric heater may be provided between port P2 and the battery 100.

[0037] The heat transfer medium circulating in the heat circuit S may be, for example, insulating oil or insulating antifreeze. The refrigeration cycle R and the heat circuit S (compressor R1, pumps W1, W2, etc.) are driven by power stored in the battery 100.

[0038] When a single cell 110 is held at a high temperature TB (for example, 40°C or higher) and a high state of charge (for example, 80% or higher), gas may be generated inside due to the decomposition reaction of the electrolyte, even without charging or discharging. The generated gas fills the inside of the single cell 110, causing the internal pressure (internal battery pressure) to rise. If the internal battery pressure rises excessively, the pressure relief valve opens. In this embodiment, the gas generated when the single cell 110 is held at a high temperature and high SOC state is suppressed from causing an increase in internal battery pressure large enough to open the pressure relief valve, thereby enabling the battery 100 to be used for a long period of time.

[0039] Figure 3 is a flowchart showing an example of the battery control process performed by the battery ECU 250 when the vehicle is stopped. This flowchart is executed repeatedly at predetermined intervals when the power switch 350 is operated, the SMR 50 is turned OFF (shut off), and the PCU 40 etc. (drive system) is in a stopped state (vehicle 1 is in a stopped state).

[0040] If vehicle 1 is stopped, step 10 (hereinafter referred to as "S") determines whether flag F is 1 or not. The initial value of flag F is set to "0", and until flag F is set to 1 in S15 (described later), it is determined to be negative and the process proceeds to S11.

[0041] In S11, it is determined whether the temperature TB of battery 100 is greater than or equal to a predetermined value α. If the temperature TB is greater than or equal to the predetermined value α (TB ≥ α), the result is positive and the process proceeds to S12. If the temperature TB is less than the predetermined value α (TB < α), the result is negative and the process proceeds to S21.

[0042] In S12, it is determined whether the State of Charge (SOC) of battery 100 is greater than or equal to a predetermined value β. If the SOC is greater than or equal to the predetermined value β (SOC ≥ β), the result is positive and the process proceeds to S13. If the SOC is less than the predetermined value β (SOC < β), the result is negative and the process proceeds to S21.

[0043] In S13, when a positive determination is made in S11 and a positive determination is made in S12, the time is integrated to calculate the cumulative time ΣT, and the process proceeds to S14. When a positive determination is made in S11 and a positive determination is made in S12, it corresponds to the "first state" of the present disclosure. The predetermined value α corresponds to the "first predetermined temperature" of the present disclosure, and the predetermined value β corresponds to the "first predetermined value" of the present disclosure. The predetermined value α and the predetermined value β are values that identify a region where gas is likely to be generated due to the decomposition reaction of the electrolytic solution while being maintained in a high-temperature and high-SOC state even when the charge and discharge of the battery 100 are not performed, and are set by experiments or the like. The cumulative time ΣT may be calculated by integrating the processing interval time of this routine.

[0044] In S14, it is determined whether the cumulative time ΣT is equal to or greater than a predetermined value s. The predetermined value s corresponds to the "set time" of the present disclosure. The cumulative time ΣT is almost proportional to the amount of gas generated inside due to the decomposition reaction of the electrolytic solution in a high-temperature and high-SOC state even when the charge and discharge of the battery 100 are not performed, and correlates with the magnitude of the internal pressure of the battery 100 (single cell 11). The predetermined value s is the time when the battery internal pressure reaches a pressure lower than the valve opening pressure (predetermined pressure) of the relief valve, and may be, for example, 2000 hours (2000h).

[0045] In S14, when the cumulative time ΣT is equal to or greater than the predetermined value s (ΣT≧s), a positive determination is made and the process proceeds to S15. When the cumulative time ΣT is less than the predetermined value s (ΣT<s), a negative determination is made and the process proceeds to S21.

[0046] In S15, after setting the flag F to 1, the process proceeds to S16. The state in which the flag F is set to 1 corresponds to the "second state" of the present disclosure.

[0047] In S16, it is determined whether the battery 100 can be cooled using the cooling device 800. If the battery 100 can be cooled by the cooling device 800, a positive determination is made and the process proceeds to S17. If the battery 100 cannot be cooled by the refrigeration cycle R due to an abnormality in the refrigeration cycle R (for example, a failure of the compressor R1) or a failure of the pump W1, etc., a negative determination is made and the process proceeds to S18. The battery ECU 250 acquires the state of the cooling device 800 via the control ECU 300.

[0048] In S17, the compressor R1 is driven using the power from battery 100, and the battery 100 is cooled by the refrigeration cycle R, ending this routine. Battery 100 is discharged and cooled. As a result, the state of charge (SOC) of battery 100 decreases and the temperature (TB) decreases. The cooling device 800 (refrigeration cycle R) is controlled via the control ECU 300.

[0049] In S18, the battery 100 is discharged, and the routine ends. Discharging from the battery 100 may be performed by operating auxiliary equipment that uses the power of the battery 100. For example, the blower of an air conditioning system (not shown) may be operated. If the refrigeration cycle R is normal but the pump W1 is faulty and the heat circuit S is abnormal, the refrigeration cycle R may be operated and the floor of the air conditioning system may be operated at the same time. Control of auxiliary equipment is performed via the control ECU 300, and if the monitoring unit 200 has a discharge resistor, the battery ECU 250 may discharge from the battery 100 using the discharge resistor. This will cause the State of Charge (SOC) of the battery 100 to decrease.

[0050] If flag F is set to 1 in S15, a positive determination is made in S10, and the process proceeds to S19. In S19, it is determined whether the temperature TB is less than or equal to a predetermined value A. The predetermined value A corresponds to the "second predetermined temperature" in this disclosure. In this embodiment, the predetermined value A is set to a value smaller than the predetermined value α. Note that the predetermined value A may be the same value as the predetermined value α. If the temperature TB is less than or equal to the predetermined value A (TB ≤ A), a positive determination is made, and the process proceeds to S21. If the temperature TB is greater than the predetermined value A (TB > A), a negative determination is made, and the process proceeds to S20.

[0051] In S20, it is determined whether SOC is less than or equal to a predetermined value B. The predetermined value B corresponds to the "second predetermined value" in this disclosure. In this embodiment, the predetermined value B is set to a value smaller than the predetermined value β. Note that the predetermined value B may be the same value as the predetermined value β. If SOC is less than or equal to the predetermined value B (SOC ≤ B), it is determined to be positive and the process proceeds to S21. If SOC is greater than the predetermined value B (SOC > B), it is determined to be negative and the process proceeds to S16.

[0052] In S21, if cooling of battery 100 is being performed, the operation of the refrigeration cycle R is stopped, and the cooling of battery 100 is stopped. Also, if battery 100 is being discharged using auxiliary equipment, etc., the discharge is stopped. If neither cooling nor discharge is being performed, that state is maintained, and this routine is terminated.

[0053] According to this embodiment, when the power switch 250 is operated and the drive system is stopped, the time spent in a state (first state) where the temperature TB is above a predetermined value α and the SOC is above a predetermined value β is accumulated and the cumulative time ΣT is calculated. The first state is a state in which gas is easily generated inside the battery even when the battery 100 is not being charged or discharged. The cumulative time ΣT is approximately proportional to the amount of gas inside the battery 100 (single cell 110) and correlates with the magnitude of the internal pressure.

[0054] When the cumulative time ΣT exceeds a predetermined value s, the flag F is set to 1. The state in which the flag F is set to 1 (second state) is a state in which the internal pressure of the battery is high. When the flag F is set to 1, the refrigeration cycle R of the cooling device 800 is activated to discharge the battery 100. If the battery 100 cannot be cooled, auxiliary equipment is activated to discharge the battery 100. When the battery 100 is discharged, the SOC decreases and it exits the first state, so gas generation becomes less likely and a further increase in the internal pressure of the battery 100 can be suppressed. Therefore, an excessive increase in internal pressure due to gas generated inside the battery when the vehicle is stopped can be suppressed. Also, when the battery 100 is cooled and the temperature TB decreases, it exits the first state, so gas generation becomes less likely and a further increase in the internal pressure of the battery 100 can be suppressed.

[0055] According to this embodiment, when flag F is set to 1 (when the second state is reached), the battery ECU 250 stops cooling and discharging the battery 100 if the temperature TB is below a predetermined value A or the SOC is below a predetermined value B. By stopping cooling and discharging, it is possible to prevent the SOC from dropping excessively and to suppress an excessive drop in the battery temperature. When flag F1 is set, and the temperature TB is higher than the predetermined value A and the SOC is higher than the predetermined value B, approaching a state where gas is likely to be generated, the cooling cycle R of the cooling device 800 is activated again to discharge the battery 100 and to discharge the battery 100. If the battery 100 cannot be cooled, auxiliary equipment is activated to discharge the battery 100. This suppresses gas generation and prevents an excessive rise in the internal pressure of the battery.

[0056] According to this embodiment, the battery 100 is a battery pack consisting of a plurality of single cells 100, and each single cell 110 is equipped with a pressure relief valve that opens when the internal pressure exceeds a predetermined pressure. The predetermined value s (set time) is set to a value such that the internal pressure of the battery does not exceed the predetermined pressure due to the gas generated inside the single cell 110. Before the internal pressure of the battery rises excessively and the pressure relief valve opens, the generation of gas can be suppressed by discharging the battery 100 and cooling the battery 100, thereby preventing the pressure relief valve from opening.

[0057] In the above embodiment, the processes S11 and S12 (Figure 3) correspond to the “determination means” of this disclosure, and the process S13 corresponds to the “accumulation means” of this disclosure.

[0058] In the above embodiment, when flag F is set to 1 in S15, the HIM device 700 may display "The cooling system will operate while the vehicle is stopped" to inform the user. This provides the user with useful information.

[0059] In the above embodiment, the cooling device 800 (refrigeration cycle R, thermal circuit S) is driven using the power of the battery 100. However, the cooling device 800 may be driven without using the power of the battery 100. For example, when the battery 100 is being charged by external power supplied from the DC inlet 60 or AC inlet 80, the external power may be used to charge the battery 100 and drive the cooling device 800.

[0060] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0061] 1 Vehicle, 2 EVSE, 10 MG, 20 Power transmission gear, 30 Drive wheels, 40 PCU, 50 SMR, 60 DC inlet, 70, 90 Charging relay, 80 AC inlet, 100 Battery, 110 Single cell (battery cell), 130 Onboard charger, 200 Monitoring unit, 250 Battery ECU, 300 Control ECU, 350 Power switch, 700 HMI device, 800 Cooling device, R Refrigeration cycle.

Claims

1. Externally rechargeable battery, A drive system that drives the vehicle using the power of the aforementioned battery, A cooling device for cooling the aforementioned battery, A vehicle equipped with a control device, The control device, when the power switch is operated and the drive system is stopped, A determination means for determining whether the battery is in a first state in which the temperature of the battery is above a first predetermined temperature and the state of care (SOC) of the battery is above a first predetermined value, Includes an integration means for accumulating the time when the first state is described above, A vehicle that discharges the battery when it reaches a second state in which the cumulative time calculated by the aforementioned accumulating means is equal to or greater than a set time.

2. The cooling device cools the battery by a refrigeration cycle that operates using the battery's power, The vehicle according to claim 1, wherein the control device operates the refrigeration cycle to perform the discharge and cool the battery.

3. When the control device enters the second state, If the temperature of the battery is below the second predetermined temperature, or if the SOC is below the second predetermined value, the discharge is stopped. The vehicle according to claim 1 or 2, wherein the discharge is performed when the temperature of the battery is higher than the second predetermined temperature and the SOC is greater than the second predetermined value.

4. Externally rechargeable battery, A drive system that drives the vehicle using the power of the aforementioned battery, A cooling device for cooling the aforementioned battery, A vehicle equipped with a control device, The control device, when the power switch is operated and the drive system is stopped, A determination means for determining whether the battery is in a first state in which the temperature of the battery is above a first predetermined temperature and the state of care (SOC) of the battery is above a first predetermined value, Includes an integration means for accumulating the time when the first state is described above, A vehicle that cools the battery with the cooling device when the cumulative time calculated by the accumulating means reaches a second state where the cumulative time is equal to or greater than a set time.

5. The aforementioned battery is a battery pack consisting of multiple battery cells, The aforementioned battery cell is equipped with a pressure relief valve that opens when the internal pressure exceeds a predetermined pressure. The vehicle according to claim 1 or claim 4, wherein the setting time is set to a value such that the internal pressure does not exceed the predetermined pressure due to the gas generated in the battery cell.

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