ENERGY STORAGE DEVICE

Abstract

An energy storage device comprises an energy storage module with an energy storage cell; a heat exchanger element that exchanges heat with the energy storage module; a thermally conductive material that is in contact with both the energy storage module and the heat exchanger element; at least one temperature sensor for detecting the temperature of the energy storage cell; and a determination unit that performs a determination process to determine whether there is an anomaly in the thermally conductive material when the energy storage cell is not being charged and discharged, wherein if the determination process determines that a magnitude of a rate of change in a detected value of the at least one temperature sensor is less than a threshold value, the determination unit determines that an anomaly occurs in the thermally conductive material.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention The present invention relates to an energy storage device. 2. Description of the state of the art JP 2005-158271 (JP 2005-158271 A) discloses a battery control unit comprising a multi-cell battery pack, a cooling airflow path arranged within the battery pack, a fan that blows air into the cooling airflow path, and a central processing unit (CPU) that detects abnormalities in the cooling airflow path. The CPU detects an abnormality in the cooling airflow path based on the current cumulative value of the battery pack's charge / discharge rate and the magnitude of the change in the battery pack's temperature. BRIEF SUMMARY OF THE INVENTION In the battery control unit described in the above-mentioned JP 2005-158271 A, abnormalities on the cooling air flow path are detected based on the current cumulative value of the charging / discharging of the battery pack, and accordingly, the above-mentioned abnormalities cannot be detected if the battery pack (energy storage module) is not being charged or discharged. The present disclosure was made to solve the above-mentioned problem, and one of its aims is to provide an energy storage device that can easily detect abnormalities occurring in the heat exchange of an energy storage module that is neither being charged nor discharged. An energy storage device according to one aspect of the present disclosure comprises an energy storage module with an energy storage cell; a heat exchanger element that exchanges heat with the energy storage module; a thermally conductive material that is in contact with both the energy storage module and the heat exchanger element; at least one temperature sensor for detecting a temperature of the energy storage cell; and a determination unit that performs a determination process to determine whether there is an anomaly in the thermally conductive material when the charging and discharging of the energy storage cell is not performed, wherein if the determination process determines that a magnitude of a rate of change in a detection value of the at least one temperature sensor is less than a threshold value, the determination unit determines that an anomaly occurs in the thermally conductive material. If, in the energy storage device according to the aspect of the present disclosure, the charging and discharging of the energy storage cell is not carried out, and it is determined that the rate of change of the detected value from at least one temperature sensor is less than the threshold value, it is determined that an anomaly has occurred in the thermally conductive material. This allows for easy determination (detection) of whether an anomaly has occurred in the thermally conductive material by simply comparing the rate of change with the threshold value. Consequently, an anomaly occurring in the heat exchange of the energy storage module, which is neither being charged nor discharged, can be easily detected. The energy storage device may further include a mounting and removal part that is detachably attached to the electrical equipment. The at least one temperature sensor may comprise several temperature sensors. If an average value of the rate of change of the temperature sensor readings when the mounting and removal part is removed from the electrical equipment is defined as the first average value, and an average value of the rate of change of the temperature sensor readings when the mounting and removal part is attached to the electrical equipment is defined, the determining unit may determine that an abnormality occurs in the thermally conductive material when the mounting and removal part is removed from the electrical equipment and is determined in the determining process.that the rate of change of the detected value from one of the temperature sensors is smaller than the first average value by a first average value or more, and can determine that an abnormality in the thermally conductive material occurs when the mounting and removal part is attached to the electrical equipment, and in the determination process it is determined that the rate of change of the detected value from one of the temperature sensors is smaller than the second average value by a second threshold value or more. Such a configuration allows the determination of whether an abnormality has occurred in the thermally conductive material by using separately set thresholds for when the mounting and removal part is removed from the electrical equipment.and when it is attached or affixed to it. Consequently, the use of a suitable threshold value according to the attached / detached state of the energy storage device allows for a proper determination of whether an abnormality is present in the thermally conductive material. The determination unit can execute the determination process in predetermined cycles and determine that an abnormality occurs in the thermally conductive material when the mounting and removal part is removed from the electrical equipment. The determination process then determines that the rate of change of the detected value from one of the temperature sensors is at least a predetermined number of times smaller than the first average value by the first threshold value, or more. Now, in a state where the mounting and removal part is removed from the electrical equipment, the external environment (e.g., the degree of solar irradiance) can differ for each part of the energy storage device (i.e., for each temperature sensor).Therefore, a decrease in the accuracy of determination due to differences in the external environment, as described above, can be prevented if an abnormality is detected when the magnitude of the rate of change is smaller than the first average value by the first threshold or more for several times or more. The determination unit can determine that an abnormality occurs in the thermally conductive material when the mounting and removal part is attached to the electrical equipment, and that the determination process determines that a difference between the average value of the temperature sensor readings and an ambient temperature of the energy storage module is greater than a threshold value, and that the rate of change of the reading from one of the temperature sensors is less than the second average value by the second threshold value or more. Now, when the mounting and removal part is attached to the electrical equipment, it is relatively unlikely that the external environment will differ for the individual energy storage cells.Furthermore, the difference between the average temperature sensor readings and the ambient temperature of the energy storage module is relatively large, so the influence of differences in the readings due to manufacturing variations between the temperature sensors is not readily apparent. Therefore, even if an anomaly in the thermally conductive material is determined to have occurred, a decrease in the accuracy of the determination process is prevented simply because the rate of change is once found to be lower than the second average value by the second threshold value or more.This ensures the accuracy of the determination regarding the presence of an anomaly in the thermally conductive material and simultaneously reduces the processing load on the determination unit by requiring the determination only once, thus enabling the anomaly determination of the thermally conductive material to be completed quickly. The energy storage device may further include a storage unit that stores information about each of the first average values ​​and the second average values, wherein the first average value is an average of the magnitude of the rate of change of the temperature sensor readings in the past when the mounting and removal part is removed from the electrical device, and the second average value is an average of the magnitude of the rate of change of the temperature sensor readings in the past when the mounting and removal part is attached to the electrical device, and wherein a first number of times and a second number of times are each a predetermined number of times equal to or greater than two, the determining unit can determine that an abnormality has occurred in the thermally conductive material.If the mounting and removal part is removed from the electrical equipment, and the determination process determines for the first number of times or more that the rate of change of the detected value from one of the temperature sensors is less than the first average value stored in the memory unit by the first threshold value or more; if the mounting and removal part is attached to the electrical equipment, and the determination process determines for the second number of times or more that the rate of change of the detected value from one of the temperature sensors is less than the second average value stored in the memory unit by the second threshold value or more. With this configuration, the anomaly detection of the thermally conductive material is performed by comparison with past average values ​​stored in the memory unit.This simplifies the determination process by the determination unit compared to the case where it is necessary to calculate an average value based on the current recorded value. Furthermore, each of the first and second counts is 2 or more, which prevents a decrease in determination accuracy due to performing the determination using past recorded values, compared to when each of the first and second counts is 1. According to the present disclosure, the occurrence of an abnormality in the heat exchange of an energy storage module in which neither charging nor discharging takes place can be easily detected. BRIEF DESCRIPTION OF THE DRAWINGS The following describes the features, advantages, and technical and industrial significance of exemplary embodiments of the invention with reference to the accompanying drawings, in which the same reference numerals denote the same elements, and wherein: Fig. 1 is a diagram showing a configuration of a vehicle and a charging station according to a first embodiment; Fig. 2 is a diagram illustrating a configuration of an energy storage device according to the first embodiment; Fig. 3 is a flowchart showing control by a processor according to the first embodiment; Fig. 4 is a diagram showing a configuration of an energy storage device according to a second embodiment; Fig. 5 is a flowchart showing control by a processor according to the second embodiment; and Fig.Figure 6 is a diagram showing a configuration of an energy storage device according to a modification of the first embodiment. DETAILED DESCRIPTION OF EXECUTION FORMS Embodiments of the present disclosure are described with reference to the drawings. It should be noted that identical or equivalent components are designated by the same reference numerals in the drawings below. First embodiment Fig. 1 is a diagram showing a vehicle 110 equipped with an energy storage device 100 according to a first embodiment of the present disclosure and a charging station 200 that exchanges energy with the vehicle 110. It should be noted that in the present disclosure, the vehicle 110 is an example of an "electrical device". The vehicle 110 comprises a vehicle body 110a, an electronic control unit (ECU) 111, a charger / discharger 112, an inlet 113 and an outside air temperature sensor 114. The outside air temperature sensor 114 detects the ambient temperature (outside air temperature) outside the vehicle 110. Vehicle 110 is electrically connected to charging station 200 via a cable 201, enabling the vehicle to exchange energy (charge and discharge) with the charging station 200. This energy exchange takes place when a plug 202, located at one end of cable 201, is connected to input 113 of vehicle 110. The vehicle 110 can be, for example, a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a battery electric vehicle (BEV), or the like. It should be noted that the energy storage device 100 can also be located in an electrical device other than a vehicle (e.g., a stationary energy storage device). When plugged in, the vehicle 110 is capable of external charging (i.e., charging the energy storage device 100 with power from outside the vehicle) and external discharging (i.e., discharging power from the energy storage device 100 to outside the vehicle). It should be noted that the vehicle 110 can also be charged externally only. The charger / discharger 112 performs the energy conversion and balancing between the charging station 200 and the energy storage device 100 during external charging and discharging. This energy conversion is controlled by the ECU 111. Fig. 2 is a diagram showing a detailed configuration of the energy storage device 100. In Fig. 2, an up-down direction in the plane of the drawing is defined as an X-direction (where up is an X1 direction and down is an X2 direction). Furthermore, a right-left direction in the plane of the drawing is defined as a Y-direction (where left is a Y1 direction and right is a Y2 direction). A direction perpendicular to the plane of the drawing is defined as a Z-direction (where forward is a Z1 direction and backward is a Z2 direction). The energy storage device 100 comprises a battery ECU 10, a positive terminal 20, a negative terminal 21, a circuit breaker 22, a current sensor 23, a circuit breaker 24, and a fuse 25. Furthermore, the energy storage device 100 comprises an energy storage module 30 with several (seven in Fig. 2) energy storage cells 31, several (three in Fig. 2) temperature sensors 32, a voltage sensor 33, a thermally conductive material 40, a heat sink 50, an ambient air temperature sensor 60, and an ECU power supply 70. It should be noted that the heat sink 50 is an example of a "heat exchange element" in the present disclosure. Furthermore, the positive terminal 20 and the negative terminal 21 are each examples of a "mounting and removal element" in the present disclosure. The energy storage device 100 is detachably mounted on the vehicle 110 (vehicle body 110a). In particular, the positive terminal 20 is detachably mounted to a terminal 110b of the vehicle 110. The negative terminal 21 is detachably mounted to a 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 disconnected from terminal 110b, and the negative terminal 21 is also disconnected from terminal 110c. When the energy storage device 100 is mounted on the vehicle 110 (vehicle body 110a), the positive terminal 20 is connected to terminal 110b, and the negative terminal 21 is also connected to terminal 110c. Thus, the positive terminal 20 and terminal 110b are electrically connected, and the negative terminal 21 and terminal 110c are electrically connected. It should be noted that Fig.Figure 2 schematically represents a state in which the energy storage device 100 is attached to the vehicle 110 (vehicle body 110a). The battery ECU 10 comprises a processor 11, a memory 12, and a communication unit 13. The memory 12 is configured to store information. The memory 12 stores programs and also information used by the programs (e.g., maps, mathematical expressions, and various parameters). In the first embodiment, the processor 11 executes a program stored in the memory 12, with the battery ECU 10 performing various operations (e.g., processing a calculated open-circuit voltage (OCV)). It should be noted, however, that such operations can be performed solely by hardware (electronic circuits) without the use of software. It should be noted that the processor 11 is an example of the "determining unit" in the present disclosure. The communication unit 13 acquires information from various devices via Controller Area Network (CAN) communication or similar methods. For example, the communication unit 13 receives acquisition values ​​from the ECU 110a, the temperature sensor 32, the voltage sensor 33, the current sensor 23, the ambient air temperature sensor 60, and so on. Furthermore, the processor 11 sends control signals via the communication unit 13 to the interrupter circuit 22, the interrupter circuit 24, etc. In the energy storage device 100, a series circuit is formed in which the positive terminal 20, the interrupter circuit 22, the energy storage module 30, the interrupter circuit 24, the fuse 25, and the negative terminal 21 are electrically arranged in this order. The current sensor 23 detects the value of the current flowing between the interrupter circuit 22 and the energy storage module 30 in the series circuit. The ECU power supply 70 provides power to the battery ECU 10. The ECU power supply 70 is electrically connected to a point 26 between the current sensor 23 and the energy storage module 30 in series, and to a point 27 between the energy storage module 30 and the interrupter circuit 24 in series. The energy storage cells 31 are electrically connected in series. It should be noted that Fig. 2 shows an example in which the energy storage cells 31 are arranged in the X direction. Each of the temperature sensors 32 is arranged in one of the energy storage cells 31. For example, the temperature sensors 32 are arranged in the energy storage cell 31 closest to the X1 side, in the energy storage cell 31 in the middle in the X direction, and in the energy storage cell 31 closest to the X2 side. It should be noted that the temperature sensors 32 can be arranged within the individual energy storage cells 31. Furthermore, Fig. 2 shows an example in which the temperature sensors 32 are arranged on the surfaces of the energy storage cells 31 on the Z1 side. It should be noted that the temperature sensors 32 can be arranged, for example, near the thermally conductive material 40. For example, the temperature sensors 32 can be arranged on a Y1-side end section of the Z1-side surface of the energy storage cells 31 or on a Y1-side side surface of the energy storage cells 31 or the like. It should be noted that the processor 11 can acquire temperature information from each of the temperature sensors 32 every unit of time (e.g., 1 minute) and calculate the rate of change of the acquired value of each temperature sensor 32 (the magnitude of the change in the acquired value per unit of time) each time. It should be noted that in the following description, the term "rate of change" refers to the magnitude (absolute value) of the rate of change. The voltage sensor 33 detects a voltage value from the individual energy storage cells 31. The thermally conductive material 40 is located adjacent to the energy storage module 30. Specifically, the thermally conductive material 40 is in contact with the Y1 side surface of each energy storage cell 31. The thermally conductive material 40 extends in the X direction such that it spans the Y1 side surfaces of each energy storage cell 31. In other words, each energy storage cell 31 is covered with the thermally conductive material 40 from the Y1 side. It should be noted that the thermally conductive material 40 can be, for example, a thermally conductive gel, grease, paste, film, or the like. The heat sink 50 is positioned adjacent to the thermally conductive material 40. The thermally conductive material 40 is in contact with both the heat sink 50 and the energy storage module. The heat sink 50 is located on the side (Y1 side) of the thermally conductive material 40 opposite the energy storage module 30. The Y1 side of the thermally conductive material 40 is covered by the heat sink 50. It should be noted that the heat sink 50 can be a solid metal plate made of aluminum or a similar material. The heat sink 50 exchanges heat with the energy storage module 30. If the temperature of the energy storage cells 31 is higher than the ambient temperature of the energy storage device 100, the heat sink 50 dissipates the heat from the energy storage cells 31 to the environment. If the temperature of the energy storage cells 31 is lower than the ambient temperature of the energy storage device 100, the heat sink 50 dissipates the ambient heat to the energy storage cells 31. The outside air temperature sensor 60 detects the ambient temperature of the energy storage cell 31. The outside air temperature sensor 60 detects the outside air temperature when the energy storage device 100 is removed from the vehicle (hereinafter referred to as the "standby" case). Furthermore, the outside air temperature sensor 60 detects the outside air 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. It is now desirable to be able to easily determine whether the heat dissipation (heat exchange) of the energy storage device is normal when the energy storage device is neither being charged nor discharged. In the first embodiment, the processor 11 (battery ECU 10) performs a determination process to ascertain whether there is an abnormality in the thermally conductive material 40 (e.g., delamination of the thermally conductive material 40) when the charging and discharging of the energy storage cells 31 is not performed. If, during the above determination process, it is determined that the rate of change of the sensing value from one of the temperature sensors 32 is less than a threshold value (described later), the processor 11 determines that an abnormality has occurred in the thermally conductive material 40. Details are described below with reference to the flowchart. Control flow A control flow for detecting an abnormality in the thermally conductive material 40 by the processor 11 (battery ECU 10) is described with reference to Fig. 3. The control flow shown in Fig. 3 can be executed in predetermined control cycles (e.g., once per minute). In step S1, processor 11 determines whether the energy storage device 100 is in a stand-alone state. For example, processor 11 can determine whether the energy storage device 100 is in a stand-alone state based on the sensing value of current sensor 23. Specifically, the reference value of current sensor 23 in the stand-alone state and the reference value of current sensor 23 when the energy storage device 100 is attached to the vehicle 110 are stored in memory 12 of the battery ECU 10, and processor 11 can perform the above determination by comparing the above reference values ​​with the sensing value of current sensor 23. If it is determined that the energy storage device 100 is in a stand-alone state (Yes in S1), processing proceeds to step S2. If it is determined that the energy storage device 100 is not in a stand-alone state (No in S1), processing proceeds to step S5. In step S2, the processor 11 determines whether the rate of change of any of the temperature sensor 32 readings is less than the average of the temperature sensor 32 readings by a threshold value A (e.g., 3 °C) or more. If any of the rate of change is less than the average by a threshold value A or more (Yes in S2), processing proceeds to step S3. If there is no temperature sensor 32 whose rate of change is less than the average by a threshold value A or more (No in S2), processing continues to step S4. It should be noted that the average value in step S2 is an example of the "first average value" in this disclosure. Furthermore, the threshold A is an example of the "first threshold" in this disclosure. In step S3, processor 11 increments a count value for temperature sensor 32 that meets the determination condition in step S2 (the rate of change is less than the average value by threshold A or more). For example, a count value for a temperature sensor 32 that was first determined to meet the conditions in step S2 is changed from 0 to 1. Furthermore, a count value for a temperature sensor 32 that was previously determined to meet the conditions in step S2, and which is again determined to meet the conditions in step S2, is changed from 1 to 2. In step S4, processor 11 determines whether there is a temperature sensor 32 whose count is equal to or greater than a threshold value B (e.g., 10). If there is a temperature sensor 32 whose count is equal to or greater than the threshold value B (Yes in S4), processing proceeds to step S9. If there is no temperature sensor 32 whose count is equal to or greater than the threshold value B (No in S4), processing ends. In step S5, processor 11 determines whether vehicle 110 is in a state where charging / discharging (operation) is stopped. Processor 11 makes this determination based on a signal from ECU 110a (Fig. 2). If vehicle 110 is in a state where charging / discharging is stopped (Yes in S5), processing proceeds to step S6. If vehicle 110 is not in a state where charging / discharging (operations) is stopped (No in S5), processing ends. In step S6, the processor 11 determines whether information about the ambient temperature of the vehicle 110 or the ambient temperature of the energy storage device 100 can be acquired. Specifically, the processor 11 determines whether the communication unit 13 has received information about the measured value from at least one of the ambient air temperature sensors 114 (Fig. 1) and 60 (Fig. 2). If the ambient temperature information has been received (Yes in S6), processing proceeds to step S7. If no ambient temperature information has been received (No in S6), processing ends.It should be noted that if information is received from both outdoor air temperature sensor 114 and outdoor air temperature sensor 60, processor 11 in step S7, which is described later, can use the measured value from one of the outdoor air temperature sensors as the ambient temperature, or an average of the measured values ​​from each of the outdoor air temperature sensors as the ambient temperature. Furthermore, if no information is received from either outdoor air temperature sensor 114 or outdoor air temperature sensor 60, this could be due to, for example, a malfunction of both outdoor air temperature sensor 114 and outdoor air temperature sensor 60. In step S7, processor 11 determines whether the difference between the average of the temperature sensor readings 32 and the ambient temperature, as determined in step S6, is equal to or greater than a threshold value C (e.g., 20 °C). If the difference between the average and the ambient temperature is equal to or greater than the threshold value C (Yes in S7), processing proceeds to step S8. If the difference between the average and the ambient temperature is less than the threshold value C (No in S7), processing terminates. In step S8, the processor 11 determines whether the rate of change of any of the temperature sensor 32's measured values ​​is less than the average of the temperature sensor 32's measured values ​​by a threshold value D (e.g., 5 °C) or more. If any of the rate of change is less than the average by a threshold value D or more (Yes in S8), processing proceeds to step S9. If there is no temperature sensor 32 whose rate of change is less than the average by a threshold value D or more (No in S8), processing terminates. That is, in step S8, processing proceeds to step S9 after only one "Yes" determination, unlike in step S2. It should be noted that the average value in step S8 is an example of a "second average value" in this disclosure. Furthermore, the threshold value D is an example of a "second threshold" in this disclosure.Furthermore, the threshold value D can be greater than the threshold value A. It should be noted that the threshold value D can be equal to or less than the threshold value A. In step S9, processor 11 performs processing to notify the user about the abnormality in the thermally conductive material 40. For example, processor 11 can transmit a message or similar information to a user connection (e.g., a smartphone) via communication unit 13 to inform the user about the abnormality in the thermally conductive material 40. Furthermore, if the energy storage device 100 is attached to the vehicle 110, the message can be displayed on the vehicle's navigation system (omitted in the figure). Additionally, if the energy storage device 100 is attached to the vehicle 110, processor 11 can, for example, control circuit breaker 22 and circuit breaker 24 to interrupt the current in the series circuit. The processing ends after step S9. It should be noted that the control flow in Fig. 3 is merely an example, and the present disclosure is not limited to this example. For instance, the processing of steps S3, S4, and S7 can be omitted. Furthermore, the counters described in steps S3 and S4 can be used if the energy storage device 100 is not in a stand-alone state (No in S1). As described above, in the first embodiment, the processor 11 determines that an anomaly has occurred in the thermally conductive material 40 when it detects that the rate of change of the temperature sensor 32's sensing value is less than the threshold value (average value - threshold A(D)). Thus, the threshold value A(D) makes it easy to determine whether an anomaly has occurred in the thermally conductive material 40. Therefore, the occurrence of an anomaly in the heat exchange of an energy storage module 30, whether charging or discharging, can be easily detected. Second embodiment A second embodiment of the present disclosure is described below with reference to Figures 4 and 5. In the second embodiment, an anomaly in the thermally conductive material 40 is determined based on the average value of past temperature sensor readings 32. It should be noted that the same configurations and processes as in the first embodiment are designated by the same reference numerals as in the first embodiment, and their description is not repeated. Fig. 4 is a diagram showing a configuration of an energy storage device 300 according to 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 10 of the first embodiment. The battery ECU 310 comprises a processor 311, a memory 312, and a communication unit 313. It should be noted that the processor 311 and the memory 312 are examples of the “determination unit” and “memory unit,” respectively, of the present disclosure. Memory 312 stores information about an average value of the rates of change of the values ​​detected by the temperature sensors 32 when the energy storage device 300 was in a stand-alone state in the past (hereinafter referred to as "average value Va"). Memory 312 also stores information about an average value of the rates of change of the detected values ​​of the temperature sensors 32 when the energy storage device 300 was attached to the vehicle in the past (hereinafter referred to as "average value Vb"). The average value Vb is stored separately for each vehicle (vehicle identification information). The average value Va is updated each time the rate of change of the detected value of each temperature sensor 32 is calculated while the energy storage device 300 is in a standstill state.The average value Vb is updated each time the rate of change of the measured value of each temperature sensor 32 is calculated in a state where the energy storage device 300 is attached to the vehicle. It should be noted that the average value Vb can be stored separately for each vehicle model. Control flow The following describes a control flow for detecting an abnormality in the thermally conductive material 40 by the processor 311 (battery ECU 310) according to the second embodiment with reference to Fig. 5. The control flow shown in Fig. 5 can be executed in predetermined control cycles (e.g., once per minute). In step S11, processor 311 determines whether the average value of the temperature sensor 32 readings lies outside a threshold range. The threshold range can be, for example, a temperature range centered around the ambient air temperature (e.g., ambient air temperature ±10 °C). Alternatively, the threshold range can be a predefined fixed value. If the average value of the temperature sensor 32 readings lies outside the threshold range (Yes in S11), processing proceeds to step S12. If the average value of the temperature sensor 32 readings lies within the threshold range (No in S11), processing terminates. It should be noted that in the present disclosure, instead of processing step S11, it can be determined, for example, whether the loading (or unloading) has been carried out. In this case, if the loading (or unloading) has been carried out, the determination in step S11 is Yes. Alternatively, it can be determined whether the average value of the measured values ​​of the temperature sensors 32 is equal to or greater than a predetermined threshold. In this case, if the average value is equal to or greater than the predetermined threshold, the determination in step S11 is Yes. Furthermore, step S11 and these determinations do not need to be carried out. In step S12, the processor 311 performs the same processing as in step S1 (Fig. 3) of the first embodiment. If it is determined that the energy storage device 300 is in a stand-alone state (Yes in S12), the processing proceeds to step S13. If it is determined that the energy storage device 300 is not in a stand-alone state (No in S12), the processing proceeds to step S14. In step S13, the processor 311 sets the average value Va as the comparison value X. The processing then proceeds to step S17. In step S14, the processor 311 performs the same processing as in step S5 (Fig. 3) in the first embodiment. If the vehicle 110 is in a state where the charging / discharging processes are stopped, the processing proceeds to step S15. If the vehicle 110 is not in a state where the charging / discharging process is stopped, the processing ends. In step S15, processor 311 determines whether the vehicle 110, to which the energy storage device 300 is attached, is a vehicle to which the energy storage device 300 has been attached in the past. Processor 311 can make this determination based on a signal received from the vehicle 110's ECU 110a via the communication unit 313. If the vehicle is a vehicle to which the energy storage device has been attached in the past (Yes in S15), processing proceeds to step S16. If the vehicle is a vehicle to which the energy storage device has not been attached in the past (No in S15), processing proceeds to step S21. In step S16, processor 311 sets an average value Vb, corresponding to vehicle 110, from the average values ​​Vb stored in memory 312 as the comparison value X. The processing then proceeds to step S17. In step S17, the processor 311 determines whether the largest value from the rate of change of the measured values ​​of the individual temperature sensors 32 (hereinafter referred to as the largest rate of change) is less than the reference value X set in step S13 or S16 by a threshold value F or more. If the largest rate of change is less than the reference value X by a threshold value F or more (Yes in S17), processing proceeds to step S18. If the largest rate of change is not less than the reference value X by a threshold value F or more (No in S17), processing proceeds to step S22. In step S18, the processor 311 increments a count value for the temperature sensor 32 that meets the requirements of step S17 (corresponding to the largest rate of change that is smaller than the reference value X by the threshold F or more). In step S19, the processor 311 determines whether there is a temperature sensor 32 whose count is equal to or greater than a threshold value G (e.g., 10). If there is a temperature sensor 32 whose count is equal to or greater than the threshold value G (Yes in S19), processing proceeds to step S20. If there is no temperature sensor 32 whose count is equal to or greater than the threshold value G (No in S19), processing terminates. It should be noted that the value of the threshold value G may differ depending on whether the energy storage device 300 is in a stand-alone state or not. Furthermore, the threshold value G is an example of the “first count value” and “second count value” in this disclosure. In step S20, the processor 311 processes the user notification of an abnormality in the thermally conductive material 40, in the same way as in step S9 (Fig. 3) in the first embodiment. The processing then ends. In step S21, processor 311 links the average value of the rate of change of the temperature sensor readings 32 with vehicle information for vehicle 110 (identification information for determining vehicle 110) and stores this information in memory 312 in the corresponding state. The processing then ends. In step S22, if the energy storage device 300 is in a stand-alone state (Yes in S12), the processor 311 reflects the measured values ​​of the individual temperature sensors 32 as the average value Va. If the energy storage device 300 is not in a stand-alone state (No in S12), the processor 311 reflects the measured values ​​of the individual temperature sensors 32 as the average value Vb. The processing then ends. It should be noted that the control flow shown in Fig. 5 is merely an example, and the present disclosure is not limited to this example. For instance, it can be determined that an abnormality has occurred in the thermally conductive material 40, regardless of the count values ​​in steps S18 and S19 (i.e., if the determination of Yes is made only once in step S17), in at least one of the cases when the energy storage device 300 is in a stand-alone state and when it is not in a stand-alone state. The other configurations and processing methods are the same as in the first embodiment and are therefore not described again. 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 a value suitable for vehicle 110. This makes it possible to determine more accurately whether an abnormality has occurred in the thermally conductive material 40. Fig. 6 shows a configuration of an energy storage device 400 according to a modification of the above embodiments. The energy storage device 400 comprises a battery pack 100a and a battery pack 100b. The battery packs 100a and 100b each have the same configuration as the energy storage device 100 according to the first embodiment. Fig. 6 is a schematic representation of a state in which the energy storage device 400 is attached to the vehicle 110. The positive terminal 20 of the battery pack 100a is connected to terminal 110b of the vehicle 110, and the negative terminal 21 of the battery pack 100b is connected to terminal 110c of the vehicle 110. Furthermore, the negative terminal 21 of the battery pack 100a and the positive terminal 20 of the battery pack 100b are electrically connected. The battery ECU 10 of battery pack 100a and the battery ECU 10 of battery pack 100b each communicate with the vehicle ECU 111 of the vehicle 110 via CAN communication or the like. It should be noted that in the example shown in Fig. 6, the ECU 111, which receives information from the individual battery ECUs 10, can determine whether an abnormality has occurred in each of the thermally conductive materials 40. In this case, the ECU 111 is contained in the energy storage device 400.The first and second embodiments described above provide an example in which the average value of the change rates of the temperature sensor readings 32 is used to determine whether an abnormality has occurred in the thermally conductive material 40, but the present disclosure is not limited to this. For example, instead of the average value, a fixed value predetermined can be used as a threshold. It should be noted that in this case, the energy storage module 30 can be equipped with only one temperature sensor 32.Furthermore, if the difference between the largest and smallest values ​​among the rates of change of the detection values ​​of the individual temperature sensors 32 is equal to or greater than a predetermined threshold, it can be determined that an abnormality has occurred in the thermally conductive material 40 (or the count value of the temperature sensor 32 corresponding to the smallest value can be increased). The first and second embodiments described above provide examples in which the heat sink 50 exchanges heat with the energy storage module 30, but the present disclosure is not limited to these. For example, instead of the heat sink 50, a tube may be provided in which a flow path is formed through which a refrigerant (e.g., coolant) flows. The second embodiment describes an example in which the anomaly determination of the thermally conductive material 40 is carried out based on the difference between a past average value and the highest rate of change, but the present disclosure is not limited to this. The anomaly determination of the thermally conductive material 40 may be carried out based on the difference between the past average value and the rate of change of the temperature sensor 32 that has the lowest rate of change in its measured values ​​among the temperature sensors 32. The configurations of the embodiments and modifications described above can be combined. It should be noted that the embodiments disclosed herein are in every respect exemplary and should not be considered limiting. The scope of this disclosure is defined more by the claims than by the above description of the embodiments and further includes all modifications that are consistent with the meaning and scope of the claims. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature JP 2005-158271

[0002] JP 2005-158271 A [0002, 0003]

Claims

Energy storage device comprising: an energy storage module with an energy storage cell; a heat exchanger element that exchanges heat with the energy storage module; a thermally conductive material that is in contact with both the energy storage module and the heat exchanger element; at least one temperature sensor for detecting the temperature of the energy storage cell; and a determination unit that performs a determination process to determine whether there is an anomaly in the thermally conductive material when the charging and discharging of the energy storage cell is not performed, wherein if the determination process determines that a magnitude of a rate of change in a detected value of the at least one temperature sensor is less than a threshold value, the determination unit determines that an anomaly occurs in the thermally conductive material. Energy storage device according to claim 1, further comprising: a mounting and removal part that is detachably mountable to an electrical device, wherein the at least one temperature sensor comprises several temperature sensors, and where an average value of the magnitude of the rate of change of the detection values ​​of the temperature sensors when the mounting and removal part is removed from the electrical equipment is defined as the first average value, and an average value of the magnitude of the rate of change of the detection values ​​of the temperature sensors when the mounting and removal part is attached to the electrical equipment is defined as the second average value, the determination unit determines that an abnormality in the thermally conductive material occurs when the mounting and removal part is removed from the electrical equipment and is determined in the determination process.that the rate of change of the detection value from one of the temperature sensors is smaller than the first average value by a first average value or more, and determines that an abnormality in the thermally conductive material occurs when the mounting and removal part is attached to the electrical equipment, and in the determining process it is determined that the rate of change of the detection value from one of the temperature sensors is smaller than the second average value by a second threshold value or more. Energy storage device according to claim 2, wherein the determination unit performs the determination processing in predetermined cycles, and determines that an abnormality occurs in the thermally conductive material when the attachment and removal part is removed from the electrical equipment, and in the determination processing it is determined that the magnitude of the rate of change of the detection value from one of the temperature sensors is smaller than the first average value by at least a predetermined number of times the first threshold value or more. Energy storage device according to claim 2 or 3, wherein the determining unit determines that an abnormality occurs in the thermally conductive material when the fastening and removal part is attached to the electrical equipment, and in the determining process it is determined that a difference between the average value of the temperature sensor readings and an ambient temperature of the energy storage module is greater than a threshold value, and it is determined that the magnitude of the rate of change of the reading from one of the temperature sensors is less than the second average value by the second threshold value or more. Energy storage device according to claim 2 or 3, further comprising: a storage unit that stores information about the first average value and the second average value, wherein: the first average value is an average value of the magnitude of the rate of change of the temperature sensor readings in the past when the mounting and removal part is removed from the electrical device, the second average value is an average value of the magnitude of the rate of change of the temperature sensors in the past when the mounting and removal part is attached to the electrical device, and with a first number of times and a second number of times each being a predetermined number of times equal to or greater than two, the determining unit determines that an abnormality has occurred in the thermally conductive material.If the mounting and removal part is removed from the electrical equipment and, during the determination process, it is determined for the first number of times or more that the rate of change of the detected value from one of the temperature sensors is less than the first average value stored in the memory unit by the first threshold value or more, and if the mounting and removal part is attached to the electrical equipment and, during the determination process, it is determined for the second number of times or more that the rate of change of the detected value from one of the temperature sensors is less than the second average value stored in the memory unit by the second threshold value or more.

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