Energy storage device

Abstract

The present invention provides an energy storage device that can easily detect abnormalities in the heat exchange of energy storage modules that are not being charged or discharged. [Solution] The energy storage device 100 includes an energy storage module 30 including an energy storage cell 31, a heat sink 50 that exchanges heat with the energy storage module 30, a thermal conductive material 40 that contacts the energy storage module 30 and the heat sink 50, a temperature sensor 32 that detects the temperature of the energy storage cell 31, and a processor 11 that performs a determination process to determine an abnormality in the thermal conductive material 40 when charging and discharging of the energy storage cell 31 is not being performed. In the determination process, the processor 11 determines that an abnormality has occurred in the thermal conductive material 40 if it determines that the magnitude of the rate of change of the value detected by the temperature sensor 32 is smaller than a threshold.

Description

Technical Field

[0001] This disclosure relates to a power storage device.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2005-158271 (Patent Document 1) discloses a battery control unit including a battery pack composed of a plurality of cells, a cooling air flow path provided in the battery pack, a cooling fan that blows air into the cooling air flow path, and a CPU that detects an abnormality in the cooling air flow path. The CPU detects an abnormality in the cooling air flow path based on the actual charge / discharge integrated value of the battery pack and the amount of temperature change of the battery pack.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the battery control unit described in Patent Document 1 above, since an abnormality in the cooling air flow path is detected based on the actual charge / discharge integrated value of the battery pack, the above abnormality cannot be detected when the battery pack (power storage module) is not being charged or discharged.

[0005] This disclosure has been made to solve the above problems, and an object thereof is to provide a power storage device capable of easily detecting that an abnormality has occurred in the heat exchange of a power storage module that is not being charged or discharged.

Means for Solving the Problems

[0006] A power storage device according to one aspect of the present disclosure comprises a power storage module including a power storage cell, a heat exchange member that exchanges heat with the power storage module, a thermal conductive material that contacts the power storage module and the heat exchange member, at least one temperature sensor that detects the temperature of the power storage cell, and a determination unit that performs a determination process to determine an abnormality in the thermal conductive material when charging and discharging of the power storage cell is not being performed. In the determination process, the determination unit determines that an abnormality has occurred in the thermal conductive material if it determines that the magnitude of the rate of change of the detected value of at least one temperature sensor is smaller than a threshold.

[0007] In an energy storage device according to one aspect of this disclosure, when charging and discharging of the energy storage cells are not being performed, if the magnitude of the rate of change of the detected value of at least one temperature sensor is determined to be smaller than a threshold, it is determined that an abnormality has occurred in the thermal conductive material. As a result, it is possible to easily determine (detect) whether or not an abnormality has occurred in the thermal conductive material simply by comparing the rate of change with the threshold. Therefore, it is possible to easily detect that an abnormality has occurred in the heat exchange of an energy storage module when charging and discharging are not being performed.

[0008] The energy storage device may further include a detachable part that can be attached to or detached from electrical equipment. At least one temperature sensor may include multiple temperature sensors. If the average of the magnitude of the rate of change of the detected values ​​of the multiple temperature sensors when the detachable part is detached from the electrical equipment is taken as the first mean value, and the average of the magnitude of the rate of change of the detected values ​​of the multiple temperature sensors when the detachable part is attached to the electrical equipment is taken as the second mean value, the determination unit may determine that an abnormality has occurred in the thermal conductive material when the detachable part is detached from the electrical equipment and the determination process determines that the magnitude of the rate of change of the detected value of any of the multiple temperature sensors is less than or equal to the first mean value by a first threshold, and when the detachable part is attached to the electrical equipment and the determination process determines that an abnormality has occurred in the thermal conductive material when the rate of change of the detected value of any of the multiple temperature sensors is less than or equal to the second mean value by a second threshold, the determination unit may determine that an abnormality has occurred in the thermal conductive material. With this configuration, it is possible to determine whether an abnormality has occurred in the thermal conductive material using thresholds separately provided for the cases when the detachable part is detached from the electrical equipment and when it is attached. As a result, by using appropriate thresholds according to the attachment / detachment state of the energy storage device, an abnormality in the thermal conductive material can be appropriately determined.

[0009] The determination unit performs a determination process at predetermined intervals. When the detachable part is removed from the electrical equipment, the determination process may determine that an abnormality has occurred in the thermal conductive material if it determines, a predetermined number of times or more, that the magnitude of the rate of change of the detected value of any of the multiple temperature sensors is less than or equal to a first threshold than the first average value. Here, when the detachable part is removed from the electrical equipment, the external environment (for example, the amount of sunlight) may differ for each part of the energy storage device (i.e., each temperature sensor). Therefore, by determining that an abnormality has occurred when it is determined that the magnitude of the rate of change is less than or equal to a first threshold than the first average value a predetermined number of times or more, it is possible to suppress a decrease in determination accuracy caused by such differences in the external environment.

[0010] The determination unit may, when the detachable unit is attached to electrical equipment, determine in the determination process that an abnormality has occurred in the thermal conductive material if it determines that the difference between the average value of the detected values ​​of multiple temperature sensors and the ambient temperature of the energy storage module is greater than a threshold, and it also determines that the magnitude of the rate of change of any of the multiple temperature sensors is less than or equal to a second threshold than the second average value. Here, when the detachable unit is attached to electrical equipment, the possibility of different external environments for each energy storage cell is relatively low. Also, because the difference between the average value of the detected values ​​of the temperature sensors and the ambient temperature of the energy storage module is relatively large, the influence of differences in detected values ​​due to manufacturing variations between temperature sensors is less likely to occur. Therefore, even if an abnormality in the thermal conductive material is determined to have occurred after only one determination that the magnitude of the rate of change is less than or equal to a second threshold than the second average value, the decrease in the determination accuracy in the above determination process is suppressed. This makes it possible to reduce the processing load on the determination unit by requiring only one determination while ensuring the accuracy of determining whether or not there is an abnormality in the thermal conductive material, and to quickly complete the abnormality determination of the thermal conductive material.

[0011] The energy storage device may further include a storage unit that stores information for a first average value and a second average value. The first average value is the average of the magnitude of the rate of change of past detected values ​​of multiple temperature sensors when the detachable unit is removed from the electrical equipment, and the second average value is the average of the magnitude of the rate of change of past detected values ​​of multiple temperature sensors when the detachable unit is attached to the electrical equipment. If the first count and the second count each are two or more predetermined counts, the determination unit may determine that an abnormality has occurred in the thermal conductive material when, in the determination process, the detachable unit is removed from the electrical equipment and the determination process determines that the magnitude of the rate of change of any of the multiple temperature sensors is less than or equal to a first threshold than the first average value stored in the storage unit for one or more counts, and when, in the determination process, the determination process determines that the magnitude of the rate of change of any of the multiple temperature sensors is less than or equal to a second threshold than the second average value stored in the storage unit for two or more counts. This configuration simplifies the judgment process by the judgment unit by performing abnormality detection of the thermal conductive material by comparing it with past average values ​​stored in the memory unit, compared to cases where an average value based on the current detected value must be calculated. Furthermore, by having both the first and second counts be 2 or more, the decrease in judgment accuracy caused by using past detected values ​​can be suppressed compared to cases where both the first and second counts are 1. [Effects of the Invention]

[0012] According to this disclosure, it is possible to easily detect when an abnormality occurs in the heat exchange of an energy storage module that is not being charged or discharged. [Brief explanation of the drawing]

[0013] [Figure 1] This diagram shows the configuration of the vehicle and power station according to the first embodiment. [Figure 2] This diagram shows the configuration of the energy storage device according to the first embodiment. [Figure 3] This is a flowchart illustrating the control of the processor according to the first embodiment. [Figure 4] This diagram shows the configuration of the energy storage device according to the second embodiment. [Figure 5] This is a flowchart illustrating the control of the processor according to the second embodiment. [Figure 6] This diagram shows the configuration of an energy storage device according to a modification of the first embodiment. [Modes for carrying out the invention]

[0014] Embodiments of this disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same number.

[0015] (First Embodiment) Figure 1 shows a vehicle 110 equipped with a power storage device 100 in the first embodiment of this disclosure, and a power stand 200 that exchanges power between the vehicle 110 and the vehicle 110. The vehicle 110 is an example of the "electrical equipment" in this disclosure.

[0016] The vehicle 110 includes a vehicle body 110a, an ECU 111, a charger / discharger 112, an inlet 113, and an outside temperature sensor 114. The outside temperature sensor 114 detects the ambient temperature (outside temperature) of the vehicle 110.

[0017] Vehicle 110 is electrically connected to power stand 200 via cable 201, enabling power exchange (charging and discharging) between it and power stand 200. This power exchange takes place with a plug 202 at the end of cable 201 connected to the inlet 113 of vehicle 110.

[0018] The vehicle 110 may be, for example, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a battery electric vehicle. The energy storage device 100 may also be installed in electrical equipment other than the vehicle (for example, a stationary energy storage device).

[0019] In the vehicle 110 in the plugin state, external charging (i.e., charging the power storage device 100 with electric power from outside the vehicle) and external discharging (i.e., discharging the electric power of the power storage device 100 to the outside of the vehicle) are possible. Note that the vehicle 110 may be capable of performing only external charging. The charger / discharger 112 performs power conversion and the like between the power stand 200 and the power storage device 100 in external charging and external discharging. This power conversion is controlled by the ECU 111.

[0020] FIG. 2 is a diagram showing a detailed configuration of the power storage device 100. In FIG. 2, the vertical direction of the paper surface is taken as the X direction (upward: X1 direction, downward: X2 direction). Also, the horizontal direction of the paper surface is taken as the Y direction (leftward: Y1 direction, rightward: Y2 direction). The direction perpendicular to the paper surface is taken as the Z direction (front side: Z1 direction, back side: Z2 direction).

[0021] The power storage device 100 includes a battery ECU 10, a positive electrode terminal 20, a negative electrode terminal 21, a cutoff circuit 22, a current sensor 23, a cutoff circuit 24, and a fuse 25. The power storage device 100 further includes a power storage module 30 including a plurality (seven in FIG. 2) of power storage cells 31, a plurality (three in FIG. 2) of temperature sensors 32, a voltage sensor 33, a heat conductive material 40, a heat dissipation plate 50, an outside air temperature sensor 60, and an ECU power supply 70. Note that the heat dissipation plate 50 is an example of the "heat exchange member" of the present disclosure. Also, each of the positive electrode terminal 20 and the negative electrode terminal 21 is an example of the "detachable portion" of the present disclosure.

[0022] The energy storage device 100 is configured to be detachable from the vehicle 110 (vehicle body 110a). Specifically, the positive terminal 20 is detachable from terminal 110b of the vehicle 110. The negative terminal 21 is detachable from terminal 110c of the vehicle 110. When the energy storage device 100 is removed from the vehicle 110 (vehicle body 110a), the positive terminal 20 is detached from terminal 110b (the connection is released), and the negative terminal 21 is detached from terminal 110c. When the energy storage device 100 is attached to the vehicle 110 (vehicle body 110a), the positive terminal 20 is attached to terminal 110b (connected), and the negative terminal 21 is attached to terminal 110c. As a result, the positive terminal 20 and terminal 110b are electrically connected, and the negative terminal 21 and terminal 110c are electrically connected. Figure 2 schematically illustrates the state in which the energy storage device 100 is attached to the vehicle 110 (vehicle body 110a).

[0023] The battery ECU 10 includes a processor 11, a memory 12, and a communication unit 13. The memory 12 is configured to store stored information. In addition to the program, the memory 12 stores information used by the program (e.g., maps, mathematical formulas, and various parameters). In the first embodiment, the processor 11 executes the program stored in the memory 12, thereby performing various processes by the battery ECU 10 (e.g., OCV calculation process). However, these processes may be performed by hardware (electronic circuits) alone without using software. The processor 11 is an example of the "determination unit" in this disclosure.

[0024] The communication unit 13 acquires information from various devices via CAN (Controller Area Network) communication, etc. For example, the communication unit 13 acquires detection values ​​from the ECU 110a, temperature sensor 32, voltage sensor 33, current sensor 23, and ambient temperature sensor 60, etc. The processor 11 also transmits control signals to the cutoff circuit 22 and cutoff circuit 24, etc., through the communication unit 13.

[0025] In the energy storage device 100, a series circuit is formed in which the positive terminal 20, the circuit breaker 22, the energy storage module 30, the circuit breaker 24, the fuse 25, and the negative terminal 21 are electrically arranged in that order. The current sensor 23 detects the current value flowing between the circuit breaker 22 and the energy storage module 30 in the above series circuit.

[0026] The ECU power supply 70 supplies power to the battery ECU 10. The ECU power supply 70 is electrically connected to point 26 between the current sensor 23 and the energy storage module 30 in the series circuit, and to point 27 between the energy storage module 30 and the circuit breaker 24 in the series circuit.

[0027] Multiple energy storage cells 31 are electrically connected in series. Figure 2 shows an example where multiple energy storage cells 31 are arranged in the X direction.

[0028] Each of the multiple temperature sensors 32 is located in one of the multiple energy storage cells 31. For example, the temperature sensors 32 are located in the energy storage cell 31 closest to X1, the energy storage cell 31 in the center in the X direction, and the energy storage cell 31 closest to X2. Note that the temperature sensors 32 may be located in each of the energy storage cells 31. Figure 2 illustrates an example where the temperature sensors 32 are located on the Z1 side surface of the energy storage cell 31. The temperature sensors 32 may also be located near, for example, the thermal conductive material 40. For example, the temperature sensors 32 may be located at the Y1 side end of the Z1 side surface of the energy storage cell 31, or on the Y1 side surface of the energy storage cell 31.

[0029] The processor 11 may acquire temperature information from each temperature sensor 32 at unit time intervals (for example, every minute) and calculate the rate of change of the detected value of each temperature sensor 32 (the amount of change in the detected value per unit time) each time. In the following, when "rate of change" is used, it refers to the magnitude (absolute value) of the rate of change.

[0030] The voltage sensor 33 detects the voltage value of each of the multiple energy storage cells 31.

[0031] The thermal conductive material 40 is positioned adjacent to the energy storage module 30. Specifically, the thermal conductive material 40 is in contact with the Y1 side surface of each of the multiple energy storage cells 31. The thermal conductive material 40 extends in the X direction so as to straddle the Y1 side surface of each of the multiple energy storage cells 31. In other words, each of the multiple energy storage cells 31 is covered from the Y1 side by the thermal conductive material 40. The thermal conductive material 40 may be, for example, a thermally conductive gel, grease, paste, or sheet.

[0032] The heat sink 50 is positioned adjacent to the thermal conductive material 40. The thermal conductive material 40 is in contact with both the heat sink 50 and the energy storage module. The heat sink 50 is positioned on the opposite side (Y1 side) from the energy storage module 30 relative to the thermal conductive material 40. The thermal conductive material 40 is covered from the Y1 side by the heat sink 50. The heat sink 50 may be a solid metal plate made of, for example, aluminum.

[0033] The heat sink 50 exchanges heat with the energy storage module 30. When the temperature of the energy storage cell 31 is higher than the ambient temperature of the energy storage device 100, the heat sink 50 dissipates heat from the energy storage cell 31 to the surroundings. Conversely, when the temperature of the energy storage cell 31 is lower than the ambient temperature of the energy storage device 100, the heat sink 50 dissipates ambient heat to the energy storage cell 31.

[0034] The ambient temperature sensor 60 detects the ambient temperature of the energy storage cell 31. The ambient temperature sensor 60 detects the ambient temperature when the energy storage device 100 is removed from the vehicle (hereinafter referred to as the standalone state). The ambient temperature sensor 60 also detects the ambient temperature or the ambient temperature of the energy storage device 100 inside the vehicle body 110a when the energy storage device 100 is attached to the vehicle.

[0035] Therefore, it is desirable to be able to easily detect whether or not the heat dissipation (heat exchange) of the energy storage device is occurring normally when charging and discharging of the device are not taking place.

[0036] In the first embodiment, the processor 11 (battery ECU 10) performs a determination process to determine an abnormality in the thermal conductive material 40 (for example, delamination of the thermal conductive material 40) when the energy storage cell 31 is not being charged or discharged. In the above determination process, the processor 11 determines that an abnormality has occurred in the thermal conductive material 40 if it determines that the rate of change of the detected value of any of the temperature sensors 32 is smaller than a threshold (described later). Further details will be explained with reference to the flowchart below.

[0037] (Control flow) Referring to Figure 3, the control flow for detecting an abnormality in the thermal conductive material 40 by the processor 11 (battery ECU 10) will be explained. The control flow shown in Figure 3 may be executed at predetermined control cycles (for example, every minute).

[0038] In step S1, the processor 11 determines whether the energy storage device 100 is in a standalone state or not. For example, the processor 11 may determine whether the energy storage device 100 is in a standalone state or not based on the detected value of the current sensor 23. Specifically, the reference value of the current sensor 23 in a standalone state and the reference value of the current sensor 23 when the energy storage device 100 is attached to the vehicle 110 are stored in the memory 12 of the battery ECU 10, and the processor 11 may perform the above determination by comparing the reference value with the detected value of the current sensor 23. If it is determined that the energy storage device 100 is in a standalone state (Yes in S1), the process proceeds to step S2. If it is determined that the energy storage device 100 is not in a standalone state (No in S1), the process proceeds to step S5.

[0039] In step S2, the processor 11 determines whether the rate of change of the detected value of any of the multiple temperature sensors 32 is less than or equal to a threshold A (for example, 3°C) than the average rate of change of the detected values ​​of the multiple temperature sensors 32. If any rate of change is less than or equal to the threshold A than the average value (Yes in S2), the process proceeds to step S3. If there are no temperature sensors 32 whose rate of change is less than or equal to the threshold A than the average value (No in S2), the process proceeds to step S4. The average value in step S2 is an example of the "first average value" in this disclosure. Also, threshold A is an example of the "first threshold" in this disclosure.

[0040] In step S3, the processor 11 increases the count of the temperature sensors 32 that satisfy the judgment conditions of step S2 (the rate of change is less than or equal to the threshold A than the average value). For example, the count of a temperature sensor 32 that is determined to satisfy the judgment conditions of step S2 for the first time changes from 0 to 1. Also, if a temperature sensor 32 that has previously been determined to satisfy the judgment conditions of step S2 is determined to satisfy the judgment conditions of step S2 again, the count changes from 1 to 2.

[0041] In step S4, the processor 11 determines whether there is a temperature sensor 32 whose count is equal to or greater than the threshold B (for example, 10). If there is a temperature sensor 32 whose count is equal to or greater than the threshold B (Yes in S4), the process proceeds to step S9. If there is no temperature sensor 32 whose count is equal to or greater than the threshold B (No in S4), the process ends.

[0042] In step S5, the processor 11 determines whether the vehicle 110 is in a charging / discharging (operation) stopped state. The processor 11 makes the above determination based on the signal from the ECU 110a (Figure 2). If the vehicle 110 is in a charging / discharging (operation) stopped state (Yes in S5), the process proceeds to step S6. If the vehicle 110 is not in a charging / discharging (operation) stopped state (No in S5), the process ends.

[0043] In step S6, the processor 11 determines whether it is possible to obtain information on the ambient temperature of the vehicle 110 or the ambient temperature of the energy storage device 100. Specifically, the processor 11 determines whether the communication unit 13 has received detection information from at least one of the ambient temperature sensor 114 (Figure 1) and the ambient temperature sensor 60 (Figure 2). If ambient temperature information has been received (Yes in S6), the process proceeds to step S7. If ambient temperature information has not been received (No in S6), the process ends. If the processor 11 has received information from both the ambient temperature sensor 114 and the ambient temperature sensor 60, in step S7 described below, it may use the detection value of either ambient temperature sensor as the ambient temperature, or it may use the average value of the detection values ​​of each ambient temperature sensor as the ambient temperature. If information has not been received from either the ambient temperature sensor 114 or the ambient temperature sensor 60, for example, if either the ambient temperature sensor 114 or the ambient temperature sensor 60 is malfunctioning.

[0044] In step S7, the processor 11 determines whether the difference between the average value of the detection values ​​from the multiple temperature sensors 32 and the ambient temperature corresponding to step S6 is greater than or equal to a threshold C (for example, 20°C). If the difference between the average value and the ambient temperature is greater than or equal to the threshold C (Yes in S7), the process proceeds to step S8. If the difference between the average value and the ambient temperature is less than the threshold C (No in S7), the process ends.

[0045] In step S8, the processor 11 determines whether the rate of change of the detected value of any of the multiple temperature sensors 32 is less than or equal to a threshold D (for example, 5°C) than the average value of the rates of change of the detected values ​​of the multiple temperature sensors 32. If the rate of change of any of the sensors is less than or equal to the threshold D than the average value (Yes in S8), the process proceeds to step S9. If there are no temperature sensors 32 whose rate of change is less than or equal to the threshold D than the average value (No in S8), the process ends. That is, unlike step S2, in step S8, the process proceeds to step S9 after only one determination of Yes. The average value in step S8 is an example of the "second average value" in this disclosure. The threshold D is also an example of the "second threshold" in this disclosure. The threshold D may be greater than the threshold A. The threshold D may also be less than or equal to the threshold A.

[0046] In step S9, the processor 11 performs a process to notify the user of an abnormality in the heat conductive material 40. For example, the processor 11 may send a message notifying the user of the abnormality in the heat conductive material 40 to the user's terminal (e.g., a smartphone) via the communication unit 13. If the energy storage device 100 is installed in the vehicle 110, the above message may also be displayed on the vehicle 110's navigation device (not shown). If the energy storage device 100 is installed in the vehicle 110, the processor 11 may also control, for example, the cutoff circuit 22 and the cutoff circuit 24 to cut off the current in the series circuit. After step S9, the process ends.

[0047] Note that the control flow in Figure 3 is merely an example, and this disclosure is not limited to this example. For example, steps S3, S4, and S7 may be omitted. Also, if the energy storage device 100 is not in a standalone state (No in S1), the counters described in steps S3 and S4 may be used.

[0048] As described above, in the first embodiment, the processor 11 determines that an abnormality has occurred in the thermal conductive material 40 when it determines that the magnitude of the rate of change of the temperature sensor 32's detected value is smaller than a threshold (average value - threshold A(D)). This makes it easy to determine whether or not an abnormality has occurred in the thermal conductive material 40 by using threshold A(D). Therefore, it is easy to detect when an abnormality has occurred in the heat exchange of the energy storage module 30 when charging and discharging are not taking place.

[0049] (Second Embodiment) Next, a second embodiment of the present disclosure will be described with reference to Figures 4 and 5. In the second embodiment, an abnormality in the thermal conductive material 40 is determined based on the past average value of the temperature sensor 32. Note that components and processes identical to those in the first embodiment will be denoted by the same reference numerals as in the first embodiment, and will not be described repeatedly.

[0050] Figure 4 shows the configuration of the energy storage device 300 in the second embodiment of the present disclosure. The energy storage device 300 differs from the energy storage device 100 of the first embodiment in that it includes a battery ECU 310 instead of the battery ECU 110 of the first embodiment. The battery ECU 310 includes a processor 311, a memory 312, and a communication unit 313. The processor 311 and the memory 312 are examples of the "determination unit" and "storage unit" of the present disclosure, respectively.

[0051] Memory 312 stores information on the average value (hereinafter referred to as average value Va) of the rate of change of the detected values ​​of the multiple temperature sensors 32 when the energy storage device 300 was left alone in the past. Memory 312 also stores information on the average value (hereinafter referred to as average value Vb) of the rate of change of the detected values ​​of the multiple temperature sensors 32 when the energy storage device 300 was installed in a vehicle in the past. Average value Vb is stored separately for each vehicle (vehicle identification information). Average value Va is updated each time the rate of change of the detected value of each temperature sensor 32 is calculated when the energy storage device 300 is left alone. Average value Vb is updated each time the rate of change of the detected value of each temperature sensor 32 is calculated when the energy storage device 300 is installed in a vehicle. Note that average value Vb may also be stored separately for each vehicle type.

[0052] (Control flow) Referring to Figure 5, the control flow for detecting an abnormality in the thermal conductive material 40 by the processor 311 (battery ECU 310) in the second embodiment will be described. The control flow shown in Figure 5 may be executed at predetermined control cycles (for example, every minute).

[0053] In step S11, the processor 311 determines whether the average value of the temperature sensor 32's detection range is outside the threshold range. The threshold range may be, for example, a temperature range centered on the ambient temperature (for example, ambient temperature ±10°C). Alternatively, the threshold range may be a fixed value set in advance. If the average value of the temperature sensor 32's detection range is outside the threshold range (Yes in S11), the process proceeds to step S12. If the average value of the temperature sensor 32's detection range is within the threshold range (No in S11), the process ends.

[0054] In this disclosure, instead of the process in step S11, it may be determined, for example, whether or not charging (or discharging) has been performed. In this case, the determination in step S11 will be Yes if charging (or discharging) has been performed. Alternatively, it may be determined whether or not the average value of the detection values ​​of the multiple temperature sensors 32 is equal to or greater than a predetermined threshold. In this case, the determination in step S11 will be Yes if the average value is equal to or greater than the predetermined threshold. Furthermore, step S11 and these determinations may not be performed.

[0055] In step S12, the processor 311 performs the same processing as in step S1 (Figure 3) of the first embodiment described above. If it is determined that the energy storage device 300 is in a standalone idle state (Yes in S12), the process proceeds to step S13. If it is determined that the energy storage device 300 is not in a standalone idle state (No in S12), the process proceeds to step S14.

[0056] In step S13, the processor 311 sets the average value Va to the comparison value X. Then the process proceeds to step S17.

[0057] In step S14, the processor 311 performs the same processing as in step S5 (Figure 3) of the first embodiment described above. If the vehicle 110 is in a charging / discharging (operation) stopped state, the process proceeds to step S15. If the vehicle 110 is not in a charging / discharging (operation) stopped state, the process ends.

[0058] In step S15, the processor 311 determines whether the vehicle 110 to which the energy storage device 300 is installed has had the energy storage device 300 installed in the past. The processor 311 may make the above determination based on a signal obtained from the ECU 110a of the vehicle 110 via the communication unit 313. If the vehicle has had the energy storage device installed in the past (Yes in S15), the process proceeds to step S16. If the vehicle has not had the energy storage device installed in the past (No in S15), the process proceeds to step S21.

[0059] In step S16, the processor 311 sets the average value Vb corresponding to the vehicle 110 from the average values ​​Vb stored in memory 312 as the comparison value X. Next, the process proceeds to step S17.

[0060] In step S17, the processor 311 determines whether the maximum value among the rate of change of each of the multiple temperature sensors 32 (hereinafter referred to as the maximum rate of change) is less than or equal to a threshold F than the comparison value X set in step S13 or S16. If the maximum rate of change is less than or equal to a threshold F than the comparison value X (Yes in S17), the process proceeds to step S18. If the maximum rate of change is not less than or equal to a threshold F than the comparison value X (No in S17), the process proceeds to step S22.

[0061] In step S18, the processor 311 increases the count of the temperature sensor 32 that satisfies the determination condition of step S17 (corresponding to the maximum rate of change that is less than or equal to the threshold F than the comparison value X).

[0062] In step S19, the processor 311 determines whether there is a temperature sensor 32 whose count is equal to or greater than a threshold G (for example, 10). If there is a temperature sensor 32 whose count is equal to or greater than a threshold G (Yes in S19), the process proceeds to step S20. If there is no temperature sensor 32 whose count is equal to or greater than a threshold G (No in S19), the process ends. The value of the threshold G may be different depending on whether the energy storage device 300 is left unattended or not. The threshold G is also an example of the "first count" and "second count" in this disclosure.

[0063] In step S20, the processor 311 performs a process to notify the user of an abnormality in the thermal conductive material 40, similar to step S9 (Figure 3) of the first embodiment described above. After that, the process ends.

[0064] In step S21, the processor 311 stores the average of the rate of change of the detected values ​​from the multiple temperature sensors 32 in memory 312, linked to the vehicle information of the vehicle 110 (identification information for identifying the vehicle 110). After that, the process ends.

[0065] In step S22, if the energy storage device 300 is left unattended (Yes in S12), the processor 311 reflects the detection values ​​of each of the multiple temperature sensors 32 into the average value Va. If the energy storage device 300 is not left unattended (No in S12), the processor 311 reflects the detection values ​​of each of the multiple temperature sensors 32 into the average value Vb. After that, the process ends.

[0066] Note that the control flow shown in Figure 5 is merely an example, and this disclosure is not limited to this example. For example, in at least one of the cases where the energy storage device 300 is left unattended and in cases where it is not left unattended, it may be determined that an abnormality has occurred in the heat conductive material 40 regardless of the counts in steps S18 and S19 (i.e., even if it is determined to be Yes only once in step S17).

[0067] Furthermore, the other configurations and processes are the same as those of the first embodiment described above, so no further explanation will be given.

[0068] In the second embodiment, as described above, the average value Vb is stored separately for each vehicle 110. This allows the magnitude of the comparison value X to be set to an appropriate value for each vehicle 110. As a result, it is possible to more accurately determine when an abnormality has occurred in the heat conductive material 40.

[0069] Figure 6 shows the configuration of a modified energy storage device 400 according to the above embodiment. The energy storage device 400 includes a battery pack 100a and a battery pack 100b. Each of the battery packs 100a and 100b has the same configuration as the energy storage device 100 of the first embodiment.

[0070] Figure 6 schematically illustrates the state in which the energy storage device 400 is attached to the vehicle 110. The positive terminal 20 of the battery pack 100a is attached to terminal 110b of the vehicle 110, and the negative terminal 21 of the battery pack 100b is attached to terminal 110c of the vehicle 110. In addition, the negative terminal 21 of the battery pack 100a and the positive terminal 20 of the battery pack 100b are electrically connected.

[0071] The battery ECU 10 of battery pack 100a and the battery ECU 10 of battery pack 100b each communicate with the ECU 111 of vehicle 110 via CAN communication or the like. In the example shown in Figure 6, the ECU 111, which has acquired information from each battery ECU 10, may determine whether or not there is an abnormality in each heat conductive material 40. In this case, the ECU 111 is included in the energy storage device 400.

[0072] In the first and second embodiments described above, examples were shown in which an abnormality in the thermal conductive material 40 is determined based on the average value of the rate of change of the detected values ​​of a plurality of temperature sensors 32, but the disclosure is not limited thereto. For example, instead of the average value, a preset fixed value may be used as a threshold. In this case, there may be only one temperature sensor 32 provided in the energy storage module 30. Furthermore, if the difference between the maximum and minimum values ​​of the rate of change of the detected values ​​of each of the plurality of temperature sensors 32 becomes greater than or equal to a predetermined threshold, it may be determined that an abnormality has occurred in the thermal conductive material 40 (or the count of the temperature sensor 32 corresponding to the minimum value is increased).

[0073] In the first and second embodiments described above, examples were shown in which the heat sink 50 exchanges heat with the energy storage module 30, but the disclosure is not limited thereto. For example, instead of the heat sink 50, piping with a flow path for a refrigerant (e.g., cooling water) may be provided.

[0074] In the second embodiment described above, an example was shown in which abnormality of the thermal conductive material 40 is determined based on the difference between the past average value and the maximum rate of change, but the disclosure is not limited thereto. Abnormality of the thermal conductive material 40 may also be determined based on the difference between the past average value and the rate of change of the temperature sensor 32 with the smallest rate of change of detected value among the multiple temperature sensors 32.

[0075] The configurations of each of the above embodiments and each of the modified examples may be combined with each other.

[0076] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of this disclosure is defined by the claims rather than the description of the embodiments above, and includes all modifications within the meaning and scope equivalent to the claims. [Explanation of Symbols]

[0077] 11,311 Processor (determination unit), 20 Positive terminal (detachable unit), 21 Negative terminal (detachable unit), 30 Energy storage module, 31 Energy storage cell, 32 Temperature sensor, 40 Thermal conductive material, 50 Heat sink (heat exchange component), 100,300,400 Energy storage device, 110 Vehicle (electrical equipment), 312 Memory (storage unit).

Claims

1. Energy storage module including energy storage cells, A heat exchange member that exchanges heat with the aforementioned energy storage module, A heat conductive material that comes into contact with each of the energy storage module and the heat exchange member, At least one temperature sensor for detecting the temperature of the energy storage cell, The system includes a determination unit that performs a determination process to determine an abnormality in the thermal conductive material when the energy storage cell is not being charged or discharged, The determination unit determines, in the determination process, that an abnormality has occurred in the heat conductive material when it determines that the magnitude of the rate of change of the detected value of the at least one temperature sensor is smaller than a threshold, in an energy storage device.

2. It further includes a detachable part that can be attached to and removed from electrical equipment, The aforementioned at least one temperature sensor includes a plurality of temperature sensors, If the average of the magnitude of the rate of change of the detected values ​​of the multiple temperature sensors when the detachable part is removed from the electrical equipment is taken as the first average value, and the average of the magnitude of the rate of change of the detected values ​​of the multiple temperature sensors when the detachable part is attached to the electrical equipment is taken as the second average value, The determination unit, When the detachable part is removed from the electrical equipment, the determination process determines that the magnitude of the rate of change of the detected value of any of the multiple temperature sensors is less than or equal to the first threshold than the first average value, and determines that an abnormality has occurred in the heat conductive material. The energy storage device according to claim 1, wherein, when the attachment / detachment part is attached to the electrical equipment, the determination process determines that an abnormality has occurred in the heat conductive material when it is determined that the rate of change of the detected value of any of the plurality of temperature sensors is less than or equal to the second average value by a second threshold.

3. The determination unit, The determination process is executed at predetermined intervals. The energy storage device according to claim 2, wherein, when the detachable part is removed from the electrical equipment, the determination process determines that an abnormality has occurred in the heat conductive material when it is determined a predetermined number of times or more that the magnitude of the rate of change of the detected value of any of the plurality of temperature sensors is less than or equal to the first threshold than the first average value.

4. The energy storage device according to claim 2 or 3, wherein the determination unit determines, in the determination process when the attachment / detachment unit is attached to the electrical equipment, that the difference between the average value of the multiple temperature sensors and the ambient temperature of the energy storage module is greater than a threshold, and that the magnitude of the rate of change of any of the multiple temperature sensors is less than or equal to the second threshold than the second average value, that an abnormality has occurred in the heat conductive material.

5. The system further comprises a storage unit that stores information for the first average value and the second average value, The first average value is the average value of the magnitude of the rate of change of past detected values ​​of the plurality of temperature sensors when the detachable part is removed from the electrical equipment. The second average value is the average value of the magnitude of the rate of change of past detected values ​​of the plurality of temperature sensors when the detachable part is attached to the electrical equipment. If the first and second counts are each two or more predetermined counts, The determination unit, When the attachment / detachment unit is removed from the electrical equipment, the determination process determines, for a first time or more, that the magnitude of the rate of change of the detected value of any of the plurality of temperature sensors is smaller than or equal to the first average value stored in the storage unit by a first threshold, and When the attachment / detachment unit is attached to the electrical equipment, in the determination process, when it is determined that the magnitude of the rate of change of the detected value of any of the plurality of temperature sensors is smaller than or equal to the second threshold than the second average value stored in the storage unit, The energy storage device according to claim 2 or 3, which determines that an abnormality has occurred in the heat conductive material.

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