Energy storage device and control device

Abstract

This provides a new approach to diagnosing faults in circuit breakers. [Solution] The energy storage device comprises an energy storage element, a circuit board 6, a circuit breaker provided on the circuit board to interrupt the current path of the energy storage element, and a diagnostic device for diagnosing faults in the circuit breaker. The circuit breaker has a plurality of switch elements 61A embedded inside the circuit board 6. The diagnostic device has a measuring unit 71A provided on the circuit board to measure the temperature of the switch elements, and a diagnostic unit that diagnoses faults in the switch elements based on the temperature measured by the measuring unit.

Description

Technical Field

[0001] One aspect of the present invention relates to a power storage device and a management device.

Background Art

[0002] A power storage device including a power storage element and a circuit breaker that interrupts the path of the current flowing through the power storage element has been developed. As the circuit breaker, a plurality of semiconductor switch elements such as MOSFET (Metal Oxide Semiconductor Field Effect Transistor), IGBT (Insulated Gate Bipolar Transistor), and bipolar transistors are used. When the bonding wire or gate oxide film inside the semiconductor is damaged due to electrical stress or thermal stress in the semiconductor switch element, there is a possibility that the conduction state (closed state) and the non-conduction state (open state) cannot be controlled.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By controlling the opening and closing of a plurality of switch elements and checking whether they are actually opened or closed, it is possible to determine the presence or absence of a failure in the switch element. However, there are cases where it is not possible to electrically check whether a plurality of switch elements have actually been opened or closed. For example, when the gate lines of a plurality of switch elements are integrated and the source terminals or drain terminals of those switch elements are at the same potential, it is not possible to electrically check whether each switch element has been opened or closed by conventional methods. One aspect of the present invention provides a new approach for diagnosing a failure of a circuit breaker.

Means for Solving the Problems

[0005] An energy storage device according to one aspect of the present invention comprises an energy storage element, a circuit board, a circuit breaker provided on the circuit board for interrupting the current path of the energy storage element, and a diagnostic device for diagnosing a malfunction of the circuit breaker. The circuit breaker has a plurality of switch elements embedded inside the circuit board. The diagnostic device has a measuring unit provided on the circuit board for measuring the temperature of the switch elements, and a diagnostic unit for diagnosing a malfunction of the switch elements based on the temperature measured by the measuring unit. [Effects of the Invention]

[0006] According to the above embodiment, the presence or absence of a fault in a switch element embedded in a circuit board can be determined based on the temperature of the switch element measured by the measurement unit. This provides a new approach to fault diagnosis of circuit breakers based on temperature. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view showing an example configuration of an energy storage device according to an embodiment. [Figure 2] This is a disassembled perspective view of an energy storage device. [Figure 3] This diagram illustrates the positions of the circuit breaker and temperature sensor on the circuit board. [Figure 4] This is an explanatory diagram illustrating the heat generation situation in the event of an open fault. [Figure 5] This is an explanatory diagram illustrating the heat generation situation in the event of a closed-loop failure. [Figure 6] This is a cross-sectional view of the circuit board (cross-sectional view of line IV-IV in Figure 3). [Figure 7] This is a cross-sectional view of the circuit board in the comparative example. [Figure 8] This is a block diagram showing the internal configuration of the control device. [Figure 9] This flowchart shows the steps the control unit takes when diagnosing an open fault. [Figure 10]This flowchart shows the procedure that the control unit performs when diagnosing a closed fault. [Figure 11] This diagram illustrates the positions of the circuit breaker and temperature sensor on the circuit board in a modified example. [Modes for carrying out the invention]

[0008] The following describes an overview of embodiments of the present invention. (1) The energy storage device comprises an energy storage element, a circuit board, a circuit breaker provided on the circuit board for interrupting the current path of the energy storage element, and a diagnostic device for diagnosing a malfunction of the circuit breaker. The circuit breaker has a plurality of switch elements embedded inside the circuit board. The diagnostic device has a measuring unit provided on the circuit board for measuring the temperature of the switch elements, and a diagnostic unit for diagnosing a malfunction of the switch elements based on the temperature measured by the measuring unit.

[0009] In the above configuration, an open-circuit faulty switch element will not have current flowing through it and its temperature will not rise. Other switch elements will have current flowing through them and their temperature will rise. Therefore, fault diagnosis can be performed based on the temperature of the switch elements measured by the measurement unit.

[0010] It is difficult to directly attach the measurement unit to the switch element. With the above configuration, since the switch element is embedded in the circuit board, the measurement unit can be easily attached near the switch element (for example, on the surface of the circuit board).

[0011] (2) In the energy storage device described in (1) above, the measurement unit may have a plurality of temperature sensors provided corresponding to the plurality of switch elements. The temperature sensor may be a contact-type sensor such as a thermistor, or a non-contact-type sensor.

[0012] With the above configuration, fault diagnosis of multiple switch elements embedded in the circuit board can be performed with greater accuracy using multiple corresponding temperature sensors.

[0013] (3) In the power storage device according to the above (1) or (2), the measurement unit may be provided on a surface of the circuit board opposite to the surface facing the power storage element, or inside the circuit board.

[0014] According to the above configuration, it is possible to suppress the influence of heat generated from the power storage element on the temperature sensor, cause the temperature sensor to detect the temperature of the switching element, and perform more accurate failure diagnosis of a plurality of switching elements.

[0015] The technology of the present disclosure may be implemented as a management device or a management method for a power storage element. (4) A management device for a power storage element includes a circuit board, a circuit breaker provided on the circuit board to cut off the current path of the power storage element, and a diagnostic device for diagnosing a failure of the circuit breaker. The circuit breaker has a plurality of switching elements embedded inside the circuit board. The diagnostic device has a measurement unit provided on the circuit board to measure the temperature of the switching element, and a diagnostic unit for diagnosing a failure of the switching element based on the temperature measured by the measurement unit.

[0016] Hereinafter, the present invention will be specifically described based on the drawings showing its embodiments. FIG. 1 is a perspective view showing a power storage device 1 according to an embodiment, and FIG. 2 is an exploded perspective view of the power storage device 1. Hereinafter, a configuration example of the power storage device 1 will be described while referring to the directions of "front and rear", "left and right", and "up and down" shown in the drawings.

[0017] The power storage device 1 is, for example, a battery (rated 12V) suitably mounted on vehicles such as engine vehicles, electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and other moving bodies.

[0018] The energy storage device 1 comprises an energy storage element 2, a busbar unit 4, and a circuit board 6. The energy storage element 2, the busbar unit 4, and the circuit board 6 are housed inside a housing case 10. The housing case 10 is made of synthetic resin. The housing case 10 comprises a case body 11 with an open top and a cover 12 that covers the opening of the case body 11. The dimensions of the case body 11 and the cover 12 are designed according to the dimensions and number of energy storage elements 2 housed inside. The case body 11 and the cover 12 are liquid-tightly fixed together with the energy storage elements 2, the busbar unit 4, and the circuit board 6 housed inside by fasteners such as screws, adhesive, or welding.

[0019] The energy storage element 2 is, for example, a lithium-ion secondary battery cell. The energy storage element 2 comprises a hollow rectangular parallelepiped case 21. The positive terminal 22 and negative terminal 23 of the energy storage element 2 are provided on the top surface of the case 21. Electrodes, electrolyte, and the like are housed inside the case 21.

[0020] The electrode body, although not shown in detail, is constructed by overlapping a sheet-shaped positive electrode and a negative electrode with two sheet-shaped separators in between, and then winding them together (either vertically or horizontally). The separators are made of a porous resin film. As the porous resin film, a porous resin film made of resin such as polyethylene (PE) or polypropylene (PP) can be used.

[0021] The positive electrode is an electrode plate in which a positive electrode active material layer is formed on the surface of a long, strip-shaped positive electrode substrate made of, for example, aluminum or an aluminum alloy. The positive electrode active material layer contains a positive electrode active material. As the positive electrode active material, a material capable of intercalating and deintercalating lithium ions can be used, such as LiFePO4. The positive electrode active material layer may further contain conductive additives, binders, etc.

[0022] The negative electrode is an electrode plate in which a negative electrode active material layer is formed on the surface of a long, strip-shaped negative electrode substrate made of, for example, copper or a copper alloy. The negative electrode active material layer contains a negative electrode active material. As the negative electrode active material, a material capable of intercalating and deintercalating lithium ions can be used, such as graphite, hard carbon, or soft carbon. The negative electrode active material layer may further contain a binder, a thickener, or the like.

[0023] The electrolyte can be the same as that used in conventional lithium-ion secondary batteries. For example, an electrolyte containing a supporting salt in an organic solvent can be used. As the organic solvent, aprotic solvents such as carbonates, esters, and ethers can be used. As the supporting salt, lithium salts such as LiPF6, LiBF4, and LiClO4 are preferably used. The electrolyte may also contain various additives such as gas generators, film-forming agents, dispersants, and thickeners.

[0024] Instead of a lithium-ion secondary battery cell, the energy storage element 2 may be a cell such as an all-solid-state battery, lead-acid battery, redox flow battery, zinc-air battery, alkaline manganese battery, lithium-sulfur battery, sodium-sulfur battery, silver-zinc oxide battery, nickel-metal hydride battery, or molten salt thermal battery, or it may be a capacitor.

[0025] Instead of a rectangular battery cell equipped with wound electrodes, the energy storage element 2 may be a cylindrical battery cell, a laminated (pouch) battery cell, or a battery cell equipped with stacked electrodes.

[0026] In this embodiment, the number of energy storage elements 2 housed in the case body 11 is four. Alternatively, the number of energy storage elements 2 housed in the case body 11 may be one or more but less than four, or more than four.

[0027] In the following description, the energy storage elements 2 will also be referred to as the first energy storage element 2A, the second energy storage element 2B, the third energy storage element 2C, and the fourth energy storage element 2D, in order from the front of the case body 11. That is, the second energy storage element 2B is positioned adjacent to the rear surface of the first energy storage element 2A, the third energy storage element 2C is positioned adjacent to the rear surface of the second energy storage element 2B, and the fourth energy storage element 2D is positioned adjacent to the rear surface of the third energy storage element 2C. In the example in Figure 2, the first energy storage element 2A and the third energy storage element 2C are housed in the case body 11 with the positive terminal 22 on the left and the negative terminal 23 on the right, while the second energy storage element 2B and the fourth energy storage element 2D are housed in the case body 11 with the positive terminal 22 on the right and the negative terminal 23 on the left.

[0028] The energy storage device 1 is provided with a charge / discharge path (current path) that electrically connects the energy storage elements 2 housed in the case body 11 to external terminals 13A and 13B. Part of the charge / discharge path is made up of busbars, which are not shown in the figure. For example, the negative terminal 23 of the first energy storage element 2A is connected to the external terminal 13A via a busbar. The positive terminal 22 of the first energy storage element 2A and the negative terminal 23 of the second energy storage element 2B are connected to each other via a busbar. The positive terminal 22 of the second energy storage element 2B and the negative terminal 23 of the third energy storage element 2C are connected to each other via a busbar. The positive terminal 22 of the third energy storage element 2C and the negative terminal 23 of the fourth energy storage element 2D are connected to each other via a busbar. The positive terminal 22 of the fourth energy storage element 2D is connected to the external terminal 13B via a busbar. In this example, the energy storage elements 2A to 2D are connected in series by busbars. Alternatively, some or all of the energy storage elements 2A to 2D may be connected in parallel.

[0029] A busbar unit 4 is positioned on the terminal surface (upper surface) of the energy storage element 2. The busbar unit 4 comprises the aforementioned busbars and a resin busbar frame 40 that holds these busbars. The busbar frame 40 covers the upper side of the multiple energy storage elements 2 and blocks the radiant heat emitted from the multiple energy storage elements 2. A circuit board 6 is positioned on the upper surface of the busbar frame 40. The circuit board 6 is fixed to the busbar frame 40 via a spacer 41, while being separated from the upper surface of the busbar frame 40. An insulating layer such as the busbar frame 40 or air exists between the circuit board 6 and the energy storage elements 2, and the circuit board 6 is positioned thermally separated from the energy storage elements 2.

[0030] The circuit board 6 includes a circuit breaker 60 for connecting or interrupting the charge / discharge path (current path) between the positive terminal 22 of the fourth energy storage element 2D and the external terminal 13B. The circuit breaker 60 is embedded in the circuit board 6. In Figure 2, the temperature sensor (see Figure 3) is not shown.

[0031] Figure 3 is a schematic diagram showing the circuit configuration of the circuit breaker 60. The circuit breaker 60 includes, for example, switch elements 61A to 63A for interrupting charging and switch elements 61B to 63B for interrupting discharging. The switch elements 61A to 63A and 61B to 63B are, for example, N-channel MOSFET (Metal Oxide Semiconductor Field Effect Transistor) chips embedded in the circuit board 6, and each has a parasitic diode. Alternatively, the switch elements 61A to 63A and 61B to 63B may be P-channel MOSFET chips.

[0032] The FET chips 61A and 61B embedded in the circuit board 6 are connected back-to-back via wiring patterns within the board, with their drains connected to each other. The source of FET chip 61A is connected to the positive terminal 22 of the energy storage element 2D via wiring patterns and busbars. The source of FET chip 61B is connected to the external terminal 13B via wiring patterns and busbars. The gates of FET chips 61A and 61B are connected to the control device 100 (see Figure 8) via wiring patterns. The FET chips 61A and 61B are configured to open and close in response to control signals (open / close signals) sent from the control device 100.

[0033] Similarly, the FET chips 62A and 62B embedded in the circuit board 6 are connected to each other via wiring patterns within the board. The source of FET chip 62A is connected to the positive terminal 22 of the energy storage element 2D via wiring patterns and busbars. The source of FET chip 62B is connected to the external terminal 13B via wiring patterns and busbars. The gates of FET chips 62A and 62B are connected to the control device 100 via wiring patterns. FET chips 62A and 62B are configured to open and close in response to control signals (open / close signals) sent from the control device 100.

[0034] Similarly, the FET chips 63A and 63B embedded in the circuit board 6 are connected to each other via wiring patterns within the board. The source of FET chip 63A is connected to the positive terminal 22 of the energy storage element 2D via wiring patterns and busbars. The source of FET chip 63B is connected to the external terminal 13B via wiring patterns and busbars. The gates of FET chips 63A and 63B are connected to the control device 100 via wiring patterns. FET chips 63A and 63B are configured to open and close in response to control signals (open / close signals) sent from the control device 100.

[0035] The circuit breaker 60 turns the FET chips 61A~63A and 61B~63B on / off under control from the control device 100. By turning on the FET chips 61A~63A for charge interruption, the circuit breaker 60 connects the charging path to the energy storage element 2, and by turning off the FET chips 61A~63A, it interrupts the charging path to the energy storage element 2. By turning on the FET chips 61B~63B for discharge interruption, the circuit breaker 60 connects the discharge path (power supply path to the load) of the energy storage element 2, and by turning off the FET chips 61B~63B, it interrupts the discharge path of the energy storage element 2.

[0036] Instead of placing the circuit breaker 60 on the positive side (high side) of the energy storage element 2, the circuit breaker 60 may be placed on the negative side (low side) of the energy storage element 2.

[0037] In this embodiment, the circuit breaker 60 is configured to include three sets (a total of six) of FET chips. Alternatively, the circuit breaker 60 may be configured to include one set (a total of two), two sets (a total of four), or four or more sets (a total of eight) of FET chips.

[0038] In this embodiment, a common-drain circuit configuration was used, in which the two MOSFET chips were connected by their drains. Alternatively, the circuit breaker 60 may have a common-source circuit configuration, in which the two MOSFET chips were connected by their sources.

[0039] In the example shown in Figure 3, for the sake of explanation, the circuit configuration is such that FET chips 61A and 61B are connected by a single wiring pattern, FET chips 62A and 62B are connected by a separate wiring pattern, and FET chips 63A and 63B are connected by yet another wiring pattern. Alternatively, a circuit configuration in which FET chips 61A to 63A and FET chips 61B to 63B are connected by a common wiring pattern P1 is also possible. That is, the drain of FET chip 61A may be connected to the respective drains of FET chips 61B to 63B by wiring pattern P1. The same applies to the drains of FET chips 62A and 63A.

[0040] In the following explanation, FET chips 61A to 63A are connected to three FET chips 61B to 63B, respectively, and it is assumed that, in the absence of a fault, the current flowing through one FET chip 61A (or 62A, 63A) is distributed among the three FET chips 61B to 63B.

[0041] This section will explain the heat generation situation when current flows through the circuit breaker 60. Figure 4 is an explanatory diagram illustrating the heat generation situation when an open fault occurs. When the FET chips 61A~63A and 61B~63B provided by the circuit breaker 60 are closed, and there are no faults in them, the current will be distributed and flow through each FET chip 61A~63A and 61B~63B. As a result, if individual differences in each element are not taken into consideration, the temperature of the FET chips 61A~63A and 61B~63B will rise uniformly.

[0042] In contrast, if an open fault occurs in some of the FET chips 61A-63A and 61B-63B (i.e., if a circuit that should be closed cannot be closed for some reason), a path where no current flows is created, reducing the number of current-distributed paths, and causing current to concentrate in the remaining paths. For example, if an open fault occurs in FET chip 62A, no current flows in the current path including FET chip 62A, and therefore current concentrates in the current path including FET chips 61A and 63A. On the other hand, since FET chips 61B-63B are each connected to the three FET chips 61A-63A, current flows in a distributed manner in the current path including FET chips 61B-63B. As a result, there is no temperature rise in FET chip 62A where no current flows, and the temperature rise of FET chips 61A and 63A, where current is concentrated, is higher than the temperature rise of FET chips 61B-63B, where current is distributed.

[0043] Figure 5 is an explanatory diagram illustrating the heat generation situation when a closed fault occurs. When the FET chips 61A~63A and 61B~63B of the circuit breaker 60 are opened, no current flows through them if there is no fault in them. As a result, the temperature of the FET chips 61A~63A and 61B~63B does not rise.

[0044] In contrast, if a closed fault occurs in some of the FET chips 61A-63A and 61B-63B (i.e., if they are unable to open for some reason when they should), current will concentrate in the current path containing the FET chip with the closed fault. For example, if a closed fault occurs in FET chip 62A, current will concentrate in FET chip 62A, and no current will flow to the other FET chips 61A, 63A, 61B-63B. As a result, the temperature of FET chip 62A, where the current is concentrated, will rise significantly, while the temperature of FET chips 61A, 63A, 61B-63B, where no current flows, will not rise.

[0045] The control device 100 according to this embodiment individually measures the temperature of each FET chip 61A~63A, 61B~63B using temperature sensors 71A~73A, 71B~73B (see Figure 3), and diagnoses a fault in the circuit breaker 60 based on the measured temperature.

[0046] Figure 6 is a cross-sectional view along line IV-IV in Figure 3, illustrating an example of the implementation of the temperature sensor 71A. The FET chip 61A embedded in the circuit board 6 is connected to other FET chips via a wiring pattern P1 embedded in the circuit board 6. The temperature sensor 71A, located on the surface of the circuit board 6 opposite the FET chip 61A, is connected to the control device 100 via a wiring pattern P2 provided on the surface of the circuit board 6. The temperature sensor 71A can detect the temperature rise of the FET chip 61A caused by current flowing through it with high accuracy and minimal time lag. The temperature sensor 71A is located on the side of the circuit board 6 opposite to the side facing the energy storage element 2 (the bottom surface in Figure 6). Therefore, the influence of temperature rises of other components besides the FET chip 61A on the temperature sensor 71A can be reduced. Alternatively, the temperature sensor 71A may be located inside the circuit board 6 (it may be embedded).

[0047] The same applies to temperature sensors 72A, 73A, and 71B-73B. They measure the temperature of the FET chips 62A, 63A, and 61B-63B, which are located opposite each other, and output the resulting temperature data to the control device 100.

[0048] Figure 7 is a comparative example illustrating the mounting position of the temperature sensor 71A when the FET chip 61A is mounted on the surface of the circuit board 6. The FET chip 61A is mounted on a wiring pattern P2 provided on the surface of the circuit board 6 via a base plate 65. The surface of the FET chip 61A is covered by a package portion 66. The temperature sensor 71A is mounted on the surface of the circuit board 6 at a position away from the FET chip 61A. In this case, the heat transfer path becomes longer, and a time lag occurs before the temperature sensor 71A detects the temperature rise of the FET chip 61A. In addition, the temperature sensor 71A is more likely to detect temperature rises of other components (e.g., other FETs) other than the FET chip 61A.

[0049] The control device 100 diagnoses faults in the circuit breaker 60 based on temperature data output from temperature sensors 71A-73A and 71B-73B. Figure 8 is a block diagram showing the internal configuration of the control device 100. The control device 100 is, for example, a BMU (Battery Management Unit) that manages the status of the energy storage device 1. In one example, the control device 100 is mounted on circuit board 6. Alternatively, the control device 100 is mounted on a separate board from circuit board 6 (for example, circuit board 7). Furthermore, the control device 100 may be a computer such as a terminal device or server device connected to the outside of the energy storage device 1.

[0050] The control device 100 includes a control unit 101, a storage unit 102, a communication unit 103, an operation unit 104, a display unit 105, and the like.

[0051] The control unit 101 is an arithmetic circuit equipped with, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The CPU of the control unit 101 reads and executes various computer programs stored in the ROM and memory unit 102, and functions as a diagnostic device to diagnose faults in the circuit breaker 60. In this embodiment, the control unit 101 diagnoses faults in the circuit breaker 60 based on the temperature measured by temperature sensors 71A~73A and 71B~73B.

[0052] Alternatively, the control unit 101 may be any arithmetic circuit equipped with multiple CPUs, a multi-core CPU, a GPU (Graphics Processing Unit), a microcontroller, volatile or non-volatile memory, etc. The control unit 101 may also include functions such as a timer for measuring the elapsed time from the time a measurement start instruction is given until a measurement end instruction is given, a counter for counting numbers, and a clock for outputting date and time information.

[0053] The storage unit 102 includes a storage device such as flash memory or a hard disk. Various computer programs and data are stored in the storage unit 102. The computer programs stored in the storage unit 102 include a diagnostic program PG that causes the computer to execute a process to diagnose a fault in the circuit breaker 60 based on the temperature measured by temperature sensors 71A~73A and 71B~73B. The data stored in the storage unit 102 includes parameters used in the diagnostic program PG and data generated by the control unit 101.

[0054] The computer program, including the diagnostic program PG, is provided on a non-temporary recording medium RM on which the computer program is recorded in a readable format. The recording medium RM is a portable memory such as a CD-ROM, USB memory, or SD (Secure Digital) card. The control unit 101 reads the desired computer program from the recording medium RM using a reading device (not shown in the figure) and stores the read computer program in the storage unit 102. Alternatively, the computer program, including the diagnostic program PG, may be provided via communication.

[0055] The communication unit 103 is equipped with a communication interface for sending and receiving various signals and data. For example, the communication unit 103 transmits control signals to the circuit board 6 to open and close the switch elements 61A~63A and 61B~63B in response to instructions from the control unit 101, and also receives temperature data output from the temperature sensors 71A~73A and 71B~73B. The communication unit 103 may also communicate with external devices such as components (e.g., an on-board ECU) within the vehicle on which the energy storage device 1 is installed.

[0056] The operation unit 104 is equipped with various input devices such as switches and buttons, and accepts user operations. The display unit 105 is equipped with a display device such as a liquid crystal display, and displays information to be notified to the user. Alternatively, the control device 100 may be configured to accept necessary operations via an external computer and transmit information to be notified to the user to the external computer. In this case, the operation unit 104 and the display unit 105 do not need to be mounted on the control device 100.

[0057] The operation of the control device 100 will be described below. Figure 9 is a flowchart showing the procedure executed by the control unit 101 when diagnosing an open fault. The control unit 101 reads the diagnostic program PG from the storage unit 102 and executes it, thereby performing the following processing: The control unit 101 sends a control signal to the circuit board 6 from the communication unit 103 to close the switch elements 61A~63A and 61B~63B, thereby closing the switch elements 61A~63A and 61B~63B (step S101). After transitioning the switch elements 61A~63A and 61B~63B to a state where they can conduct electricity, the control unit 101 flows a current for a short time (for example, 1 second) (step S102). If the switch elements 61A~63A and 61B~63B are already closed when the diagnosis of the open fault is started, the processing in step S101 may be omitted.

[0058] The control unit 101 acquires temperature data output from temperature sensors 71A~73A and 71B~73B via the communication unit 103 (step S103).

[0059] The control unit 101 diagnoses a fault in the circuit breaker 60 based on the acquired temperature data (step S104). If an open fault occurs in some of the switch elements 61A~63A, 61B~63B of the circuit breaker 60, three types of states occur: a path where no current flows, a path where current is concentrated, and a path where current is dispersed. The degree of temperature rise of the switch elements 61A~63A, 61B~63B differs depending on whether they are located in a path where no current flows, a path where current is concentrated, or a path where current is dispersed. The control unit 101 measures the temperature of each switch element 61A~63A, 61B~63B and compares the degree of temperature rise between the elements to determine whether an open fault has occurred. Furthermore, the control unit 101 may identify the switch element with the lowest degree of temperature rise as the switch element that has experienced an open fault.

[0060] The control unit 101 determines whether or not an open fault has been detected (step S105). If it determines that no open fault has been detected (S105: NO), it outputs information to that effect (step S106). On the other hand, if it determines that an open fault has been detected (S105: YES), the control unit 101 outputs information to that effect (step S107). For example, the control unit 101 displays text information indicating that an open fault has been detected (or that no open fault has been detected) on the display unit 105. Alternatively, the control unit 101 may notify the user terminal of the information indicating that an open fault has been detected (or that no open fault has been detected) via the communication unit 103. If the control unit 101 identifies the switch element that has experienced an open fault, it may also output information about the switch element that has experienced an open fault (for example, information about the connection location).

[0061] After diagnosing the open fault, the control unit 101 may send a control signal from the communication unit 103 to the circuit board 6 to open each of the switch elements 61A~63A and 61B~63B, thereby opening the switch elements 61A~63A and 61B~63B.

[0062] Figure 10 is a flowchart showing the procedure executed by the control unit 101 when diagnosing a closed fault. The control unit 101 reads the diagnostic program PG from the storage unit 102 and executes it, thereby performing the following processes: The control unit 101 determines whether or not it is permissible to open the switch elements 61A~63A and 61B~63B (step S121). For example, the control unit 101 communicates with the in-vehicle ECU through the communication unit 103 to determine whether or not there are any devices operating that are receiving power from the energy storage device 1. If there are no operating devices, it determines that it is permissible to open the switch elements 61A~63A and 61B~63B. If it is determined that it is permissible to open them (S121: YES), the control unit 101 executes the processes from step S122 onwards. If it is determined that it is not permissible to open them (S121: NO), the control unit 101 terminates the process according to this flowchart.

[0063] The control unit 101 transmits a control signal from the communication unit 103 to the circuit board 6 to open the switch elements 61A~63A and 61B~63B, thereby opening the switch elements 61A~63A and 61B~63B (step S122). The control unit 101 then supplies a short current (for example, 1 second) to the switch elements 61A~63A and 61B~63B (step S123).

[0064] The control unit 101 acquires temperature data output from temperature sensors 71A~73A and 71B~73B via the communication unit 103 (step S124).

[0065] The control unit 101 diagnoses a fault in the circuit breaker 60 based on the acquired temperature data (step S125). Specifically, if an open fault occurs in some of the switch elements 61A~63A, 61B~63B of the circuit breaker 60, two types of states will occur: one path where no current flows and another path where current concentrates. This will result in a difference in the degree of temperature rise of the switch elements 61A~63A, 61B~63B. The control unit 101 will then detect this difference in temperature rise to determine whether or not a closed fault has occurred. Furthermore, the control unit 101 may identify the switch element with the highest temperature rise as the switch element that has experienced a closed fault.

[0066] The control unit 101 determines whether or not a closed fault has been detected (step S126). If it determines that no closed fault has been detected (S126: NO), it outputs information to that effect (step S127). On the other hand, if it determines that a closed fault has been detected (S126: YES), the control unit 101 outputs information to that effect (step S128). For example, the control unit 101 displays text information indicating that a closed fault has been detected (or that no closed fault has been detected) on the display unit 105. Alternatively, the control unit 101 may notify the user terminal via the communication unit 103 that an open fault has been detected (or that no closed fault has been detected). If the control unit 101 identifies the switch element that has experienced a closed fault, it may also output information about the switch element that has experienced a closed fault (for example, information about the connection position).

[0067] As described above, in this embodiment, it is possible to determine whether or not there is a fault without individually controlling the opening and closing of the switch elements 61A to 63A and 61B to 63B.

[0068] The disclosed embodiments are illustrative in all respects and not restrictive. The scope of the invention is defined by the claims and includes all modifications in the sense and scope equivalent to the claims.

[0069] For example, although the embodiment described an application example in the energy storage device 1, the diagnostic method described in the embodiment can also be applied to power supply devices, transformers, electrical equipment, and circuit breakers mounted on electronic equipment.

[0070] The control device 100 may detect signs of failure in the circuit breaker 60 by performing the above-described fault diagnosis as needed. For example, the control device 100 may determine that it has detected signs of failure if it detects a difference of a predetermined percentage or more in the measured temperature rise. If the control device 100 determines that it has detected signs of failure, it may actually control the opening and closing of the corresponding switch element to diagnose whether or not a failure has occurred.

[0071] In the embodiment described, the case in which fault diagnosis of the circuit breaker 60 was determined by short-term energization was explained. The concept of the present invention is that fault determination of a switch element is determined by whether or not the switch element is within the assumed temperature range during assumed operation (when energized). Therefore, in addition to short-term energization when fault diagnosis of the circuit breaker 60, it is also possible to obtain the temperature of each switch element 61A~63A, 61B~63B and perform fault diagnosis based on whether or not the obtained temperature is within the assumed range. For example, the control device 100 may estimate the temperature of the switch elements 61A~63A, 61B~63B from the energization history, and perform fault diagnosis of the switch elements 61A~63A, 61B~63B after confirming whether or not the temperature of the switch elements 61A~63A, 61B~63B is within the assumed temperature range.

[0072] In this embodiment, fault diagnosis of switch elements 61A~63A, 61B~63B is performed based on the heat generation phenomenon of switch elements 61A~63A, 61B~63B when energized. Therefore, if, for example, the temperature change of each switch element 61A~63A, 61B~63B cannot be obtained, or if only a change within the margin of error can be obtained, due to prolonged periods of inactivity, fault diagnosis of switch elements 61A~63A, 61B~63B may be performed using the procedure shown in Figure 9 or Figure 10. If the switch elements 61A~63A, 61B~63B heat up to a certain temperature or higher after prolonged operation, it may be difficult to obtain the temperature difference between each switch element 61A~63A, 61B~63B. In such cases, fault diagnosis of switch elements 61A~63A, 61B~63B may be performed under conditions where temperature differences are likely to occur, such as by allowing time for the switch elements 61A~63A, 61B~63B to cool down before performing the diagnosis.

[0073] As shown in Figure 11, the temperature sensors 71C, 72C, and 73C may be provided between the switch elements 61A to 63A for interrupting charging and the switch elements 61B to 63B for interrupting discharge. In this specification, such a configuration is also included in the meaning of "provided in correspondence with the switch elements." [Explanation of symbols]

[0074] 1. Energy storage device 2 Energy storage element 6 Circuit board 60 Circuit breakers 61A~63A, 61B~63B FET chip (switch element) 71A~73A, 71B~73B, 71C~73C Temperature Sensor (Measurement Unit) 100 Control device (diagnostic unit)

Claims

1. Energy storage element, Circuit board and A circuit breaker provided on the circuit board for interrupting the current path of the energy storage element, The system includes a diagnostic device for diagnosing a fault in the circuit breaker, The circuit breaker has a plurality of switch elements embedded inside the circuit board, The diagnostic device includes a measuring unit provided on the circuit board for measuring the temperature of the switch element, and a diagnostic unit for diagnosing a malfunction of the switch element based on the temperature measured by the measuring unit. Energy storage device.

2. The energy storage device according to claim 1, wherein the measurement unit has a plurality of temperature sensors provided corresponding to the plurality of switch elements.

3. The energy storage device according to claim 1 or claim 2, wherein the measuring unit is provided on the side of the circuit board opposite to the side facing the energy storage element, or inside the circuit board.

4. A device for managing energy storage elements, Circuit board and A circuit breaker provided on the circuit board for interrupting the current path of the energy storage element, The system includes a diagnostic device for diagnosing a fault in the circuit breaker, The circuit breaker has a plurality of switch elements embedded inside the circuit board, The diagnostic device includes a measuring unit provided on the circuit board for measuring the temperature of the switch element, and a diagnostic unit for diagnosing a malfunction of the switch element based on the temperature measured by the measuring unit. Management device.

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