Relay fault diagnosis method and power storage device system

Abstract

To shorten a time required for fault diagnosis of a relay included in a power storage device pack.SOLUTION: A relay fault diagnosis method is a method for diagnosing relay faults in a power storage device system 1 including a plurality of power storage device packs 10, 20. The relay fault diagnosis method is executed by a controller 50. The relay fault diagnosis method includes a diagnostic process S1 and a change process S2. In the diagnostic process S1, a fault in the relays of some of the power storage device packs 10, 20 is diagnosed when the power storage device system 1 is started. In the change process S2, the power storage device pack that is the target of the fault diagnosis is changed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a relay fault diagnosis method and an electricity storage device system. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2017-117618 discloses a relay fault diagnosis method for multiple power supplies connected in parallel. Each of the multiple power supplies has a relay on both the positive and negative poles. The relay fault diagnosis method disclosed in this publication performs an open / close drive that switches the relay on and off based on the voltage of the power supply, and diagnoses whether the relay operates as instructed. The open / close drive includes a first step, a second step, and a third step. In the first step, multiple relays provided on one of the positive and negative poles are closed sequentially in the parallel direction. In the second step, multiple relays provided on one pole are opened collectively. In the third step, multiple relays provided on the other of the positive and negative poles are closed sequentially in the parallel direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-117618 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors wish to shorten the time required to perform fault diagnosis on a relay included in an electricity storage device pack. [Means for solving the problem]

[0005] The relay fault diagnosis method disclosed herein is a relay fault diagnosis method for an electricity storage device system including a plurality of electricity storage device packs. The relay fault diagnosis method is executed by a controller. The relay fault diagnosis method includes a diagnosis process and a change process. The diagnosis process diagnoses faults in relays of some of the plurality of electricity storage device packs when the electricity storage device system is started. The change process changes the electricity storage device pack that is the target of the fault diagnosis. This relay fault diagnosis method reduces the time required to perform fault diagnosis on relays included in the electricity storage device packs. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram showing an electricity storage device system 1. As shown in FIG. [Figure 2] FIG. 2 is a flowchart showing the processing executed by the controller 50. [Figure 3] FIG. 3 is a flowchart showing the processing executed by the controller 50 when the electricity storage device system 1 is started up. [Figure 4] FIG. 4 is a time chart showing the state of the relay. [Figure 5] FIG. 5 is a flowchart showing the process executed by the controller 50 when the power storage device system 1 is shut down. DETAILED DESCRIPTION OF THE INVENTION

[0007] An embodiment of the technology disclosed herein will be described below with reference to the drawings. The embodiment described here is, of course, not intended to limit the present invention. The drawings are schematic and do not necessarily reflect the actual product. Furthermore, the same reference numerals are appropriately used for components and parts that perform the same function, and redundant explanations will be omitted where appropriate.

[0008] <Electricity storage device system 1> FIG. 1 is a schematic diagram showing an electricity storage device system 1. The electricity storage device system 1 is also referred to as an electricity storage device pack and is an assembly including electricity storage devices, a configuration for controlling the electricity storage devices, and the like. As shown in FIG. 1, the electricity storage device system 1 includes a plurality of electricity storage device packs 10, 20 connected in parallel, and a controller 50. In this embodiment, the electricity storage device system 1 includes two electricity storage device packs 10, 20. The electricity storage device system 1 includes a first electricity storage device pack 10 and a second electricity storage device pack 20. The number of electricity storage device packs included in the electricity storage device system 1 is not particularly limited and may be three or more, for example, four. The number of electricity storage device packs included in the electricity storage device system 1 is not particularly limited and may be 10 or less.

[0009] The electricity storage device system 1 is connected in series to a load 60. Power is supplied to the load 60 from a plurality of electricity storage devices of the electricity storage device system 1. In this embodiment, the electricity storage device system 1 is connected to the load 60 of an electric vehicle. Although not particularly limited, the load 60 may be constituted, for example, by an electric motor, an inverter, etc. of the vehicle. Note that the load 60 is not limited to this form, and the electricity storage device system 1 can also be applied to systems other than electricity storage device systems mounted on electric vehicles. Furthermore, the electricity storage device system 1 is connected to a charger (not shown) and is configured to be capable of charging and discharging.

[0010] The first electricity storage device pack 10 and the second electricity storage device pack 20 are connected in parallel. The first electricity storage device pack 10 and the second electricity storage device pack 20 are also connected in parallel to the load 60.

[0011] <Multiple power storage device packs 10, 20> The multiple power storage device packs 10, 20 each include a power storage device 11, 21 having a positive electrode and a negative electrode, a positive electrode relay 12, 22, and a negative electrode relay 13, 23. The positive electrode relays 12, 22 are connected to the positive electrode sides of the power storage devices 11, 21. The negative electrode relays 13, 23 are connected to the negative electrode sides of the power storage devices 11, 21. The power storage device packs 10, 20 each include lower-level controllers 51, 52. The power storage device packs 10, 20 each include voltage sensors 15, 25. The power storage device 11, positive electrode relay 12, negative electrode relay 13, lower-level controller 51, and voltage sensor 15 of the first power storage device pack 10 are housed in a pack case (not shown). The power storage device 21, positive electrode relay 22, negative electrode relay 23, lower-level controller 52, and voltage sensor 25 of the second power storage device pack 20 are housed in a pack case (not shown). The pack case is a sealed container made of metal (for example, aluminum or aluminum alloy).

[0012] <Electricity Storage Devices 11, 21> The power storage devices 11 and 21 are power storage devices capable of extracting electrical energy. The power storage devices 11 and 21 include secondary batteries that can be repeatedly charged and discharged by the movement of charge carriers between a pair of electrodes (positive and negative electrodes) via an electrolyte. The power storage devices 11 and 21 include, for example, lithium-ion secondary batteries, nickel-metal hydride batteries, etc. The power storage device packs 10 and 20 may include one power storage device or multiple power storage devices (cells). The multiple cells may be electrically connected to each other via bus bars or the like to form a power storage device module. In the power storage device module, the multiple cells may be connected in series, in parallel, or in a combination of series and parallel connections. When the power storage devices 11 and 21 are power storage device modules, the number of cells is not particularly limited. The power storage devices 11 and 21 may include, for example, 10 or more cells, or may include 100 or more cells. The number of cells included in the power storage devices 11 and 21 may be, for example, 200 or less. The power storage devices 11 and 21 are connected to the load 60 via external output terminals (not shown) and supply power to the load 60 .

[0013] Voltage sensors 15 and 25 are connected in parallel to the power storage devices 11 and 21. The voltages of the power storage devices 11 and 21 are detected by the voltage sensors 15 and 25. The voltage sensor 15 detects the voltage of the power storage device 11. The voltage sensor 25 detects the voltage of the power storage device 21. If a malfunction occurs in one of the voltage sensors 15 and 25, one of the voltage sensors may detect the voltages of both the power storage devices 11 and 21. Alternatively, the power storage device system 1 may be provided with one voltage sensor that detects both the power storage devices 11 and 21. The voltages detected by the voltage sensors 15 and 25 are transmitted to the controller 50.

[0014] <Positive relays 12, 22, negative relays 13, 23> The positive electrode relays 12, 22 and the negative electrode relays 13, 23 are connected in series to the power storage devices 11, 21. There are no particular limitations on the positive electrode relays 12, 22 and the negative electrode relays 13, 23 as long as they are capable of switching between connection and disconnection between the power storage devices 11, 21 and the load 60. As the positive electrode relays 12, 22 and the negative electrode relays 13, 23, electromechanical relays or semiconductor relays may be used.

[0015] The power storage device packs 10, 20 include precharge circuits 14, 24. The precharge circuits 14, 24 are circuits in which precharge resistors 14a, 24a and precharge relays 14b, 24b are connected in series. The precharge circuits 14, 24 are circuits that prevent inrush current from flowing to the load 60 when power is supplied from the power storage device system 1 to the load 60. The precharge circuits 14, 24 are connected in parallel to the positive electrode relays 12, 22. Note that the precharge circuits 14, 24 may also be connected in parallel to the negative electrode relays 13, 23.

[0016] Before the load 60 is started, the positive electrode relays 12 and 22, the negative electrode relays 13 and 23, and the pre-charge relays 14b and 24b are in an open state. When the power storage device system 1 connected to the load 60 is started, the negative electrode relays 13 and 23 and the pre-charge relays 14b and 24b are switched to a closed state. The load 60 is connected to the power storage device system 1 via the pre-charge circuits 14 and 24. At this time, because the pre-charge circuits 14 and 24 are provided with the pre-charge resistors 14a and 24a, power is supplied to the load 60 from the power storage devices 11 and 21 at a low current. Thereafter, with the potential of the load 60 increased, the positive electrode relays 12 and 22 are switched to a closed state, and then the pre-charge relays 14b and 24b are switched to an open state. This prevents a large current from flowing through the load 60. The opening and closing of the positive relays 12 and 22, the negative relays 13 and 23, and the pre-charge relays 14b and 24b are controlled by a controller 50. In this embodiment, the opening and closing of the positive relay 12, the negative relay 13, and the pre-charge relay 14b is controlled by a lower-level controller 51. The opening and closing of the positive relay 22, the negative relay 23, and the pre-charge relay 24b is controlled by a lower-level controller 52.

[0017] <Controller 50> The controller 50 controls the opening and closing of the positive electrode relays 12, 22 and the negative electrode relays 13, 23. The controller 50 is configured to be able to communicate with the voltage sensors 15, 25.

[0018] The controller 50 may be, for example, a computer such as an ECU (Electronic Control Unit) or a circuit board equipped with a microcomputer. The computer may include, for example, an interface (I / F) for receiving data from an external device, a central processing unit (CPU) for executing program instructions, a ROM for storing the program executed by the CPU, a RAM used as a working area for expanding the program, and a storage device (recording medium) such as a memory for storing the program and various data. The relay fault diagnosis method disclosed herein may be realized by cooperation between a predetermined program (software) and a computer (hardware) that executes the program. Relay fault diagnosis may be performed by cooperation between multiple controllers. The relay fault diagnosis method may be realized, for example, by cooperative processing between multiple computers connected via a network.

[0019] In this embodiment, the controller 50 includes a host controller 55 and subordinate controllers 51 and 52. The host controller 55 is configured to be able to communicate with the subordinate controllers 51 and 52. The host controller 55 and subordinate controllers 51 and 52 may be configured to be able to communicate with each other via wired or wireless communication. The host controller 55 includes a storage unit 55a, a command unit 55b, and a determination unit 55c. The subordinate controllers 51 and 52 include communication units 51a and 52a, command units 51b and 52b, determination units 51c and 52c, and acquisition units 51d and 52d. Each unit of the controller 50 may be realized by one or more processors or may be incorporated into a circuit. Furthermore, since each unit of the subordinate controller 51 and the subordinate controller 52 executes the same process, redundant description will be omitted where appropriate.

[0020] The relay fault diagnosis method disclosed herein will be described below. The relay fault diagnosis method for an electricity storage device system 1 including a plurality of electricity storage device packs 10, 20 is executed by a controller 50. Fig. 2 is a flowchart showing the processing executed by the controller 50. As shown in Fig. 2, the relay fault diagnosis method includes a diagnostic process S1 for diagnosing a relay fault and a change process S2 for changing the electricity storage device pack that is the target of the fault diagnosis.

[0021] <Diagnosis process S1> The diagnostic process S1 is executed at the start of the power storage device system 1. In the diagnostic process S1, the controller 50 diagnoses faults in the relays of some of the power storage device packs 10, 20.

[0022] The controller 50 (in this embodiment, the memory unit 55a of the upper controller 55) stores the order of fault diagnosis of the multiple power storage device packs 10, 20. In this embodiment, the memory unit 55a stores the number of times the power storage device system 1 has been started up. When the power storage device system 1 is started up an odd-numbered time, the first power storage device pack 10 of the multiple power storage device packs 10, 20 is diagnosed for a fault in its relay. When the power storage device system 1 is started up an even-numbered time, the second power storage device pack 20 of the multiple power storage device packs 10, 20 is diagnosed for a fault in its relay.

[0023] When the power storage device system 1 is started up an odd number of times, the command unit 55b of the upper controller 55 transmits an inspection command to the lower controller 51. The inspection command may be a signal transmitted from the command unit 55b of the upper controller 55. The communication unit 51a of the lower controller 51 receives the inspection command. When the inspection command is transmitted to the lower controller 51 of the first power storage device pack 10, a fault diagnosis of the power storage device 11 included in the first power storage device pack 10 is started.

[0024] The command unit 51b of the lower-level controller 51 controls the opening and closing of the positive electrode relay 12, the negative electrode relay 13, and the pre-charge relay 14b of the first power storage device pack 10 in a predetermined order.

[0025] When the electricity storage device system 1 is started up, the positive electrode relay 12 and the negative electrode relay 13 of the electricity storage device pack 10 are set to an open state. Similarly, the positive electrode relay 22 and the negative electrode relay 23 of the electricity storage device pack 20 are set to an open state.

[0026] Fig. 3 is a flowchart showing the processing executed by the controller 50 when the power storage device system 1 is started up. Fig. 3 shows the processing executed when the power storage device system 1 is started up an odd number of times. Fig. 4 is a time chart showing the states of the relays. Fig. 4 shows the processing executed by the controller 50 when the power storage device system 1 is started up and shut down.

[0027] As shown in FIGS. 3 and 4, in step S11, the command unit 51b commands the precharge relay 14b of the power storage device pack 10 to be in a closed state.

[0028] In step S12, the determination unit 51c determines whether or not the negative electrode relay 13 has a closed fault, based on the voltage of the power storage device 11 acquired by the acquisition unit 51d. If the negative electrode relay 13 does not have a closed fault (if it is normal), the power storage device 11 and the load 60 are not connected even if the pre-charge relay 14b is closed. For this reason, the voltage of the power storage device 11 does not increase before and after the pre-charge relay 14b is opened and closed. If the negative electrode relay 13 has a closed fault, the power storage device 11 and the load 60 are connected by the pre-charge relay 14b and the negative electrode relay 13 with the closed fault. If the voltage of the power storage device 11 increases after the pre-charge relay 14b is closed, the determination unit 51c determines that the negative electrode relay 13 has a closed fault. For example, a voltage reference value may be set in advance, and if the voltage acquired by the acquisition unit 51d is higher than the reference value, it may be determined that the negative electrode relay 13 has a closed fault. The process performed by the determination unit 51c may be executed by the determination unit 55c of the upper controller 55.

[0029] If the negative relay 13 has a closed fault (Yes), the communication unit 51a of the lower controller 51 notifies the upper controller 55 that the negative relay 13 has a closed fault. The command unit 55b of the upper controller 55 halts the start-up of the electricity storage device system 1. If the negative relay 13 does not have a closed fault (No), proceed to step S13.

[0030] In step S13, the command unit 51b commands the pre-charge relay 14b to be in the open state. In step S14, the command unit 51b commands the negative electrode relay 13 to be in the closed state. In step S15, the command unit 51b commands the pre-charge relay 14b to be in the closed state.

[0031] In step S16, the determination unit 51c determines whether or not the negative electrode relay 13 has an open circuit fault, based on the voltage of the power storage device 11 acquired by the acquisition unit 51d. If the negative electrode relay 13 does not have an open circuit fault (if it is normal), when the precharge relay 14b is closed, the power storage device 11 and the load 60 are connected by the precharge relay 14b and the negative electrode relay 13. Therefore, after the precharge relay 14b is closed, the voltage of the power storage device 11 increases. If the negative electrode relay 13 has an open circuit fault, the power storage device 11 and the load 60 are not connected. If the voltage of the power storage device 11 does not increase after the precharge relay 14b is closed, the determination unit 51c determines that the negative electrode relay 13 has an open circuit fault. For example, a voltage reference value may be set in advance, and if the voltage acquired by the acquisition unit 51d is lower than the reference value, the determination unit 51c may determine that the negative electrode relay 13 has an open circuit fault.

[0032] If the negative relay 13 has an open circuit fault (Yes), the communication unit 51a of the lower-level controller 51 notifies the upper-level controller 55 that the negative relay 13 has an open circuit fault. The command unit 55b of the upper-level controller 55 halts the startup of the electricity storage device system 1. If the negative relay 13 does not have an open circuit fault (No), proceed to step S17.

[0033] In step S17, the command unit 51b instructs the positive electrode relay 12 to close. After the potential of the load 60 increases, in step S18, the command unit 51b instructs the pre-charge relay 14b to open.

[0034] In step S19, the determination unit 51c determines whether or not the positive electrode relay 12 has an open circuit fault, based on the voltage of the power storage device 11 acquired by the acquisition unit 51d. If the positive electrode relay 12 does not have an open circuit fault (if it is normal), when the pre-charge relay 14b is opened, the power storage device 11 and the load 60 are connected by the positive electrode relay 12 and the negative electrode relay 13. Therefore, the voltage of the power storage device 11 is constant before and after the pre-charge relay 14b is opened and closed. If the positive electrode relay 12 has an open circuit fault, the connection between the power storage device 11 and the load 60 is cut off. If the voltage of the power storage device 11 drops after the pre-charge relay 14b is closed, the determination unit 51c determines that the positive electrode relay 12 has an open circuit fault.

[0035] If the positive relay 12 has an open circuit fault (Yes), the communication unit 51a of the lower-level controller 51 notifies the upper-level controller 55 that the positive relay 12 has an open circuit fault. The command unit 55b of the upper-level controller 55 halts the start-up of the electricity storage device system 1. If the positive relay 12 does not have an open circuit fault (No), the process proceeds to step S20.

[0036] If a close fault or an open fault of the negative electrode relay 13 and an open fault of the positive electrode relay 12 have not been detected up to step S19, the first electricity storage device pack 10 is started up normally. After the first electricity storage device pack 10 has started up, the second electricity storage device pack 20 is started up. The start-up of the second electricity storage device pack 20 may be instructed, for example, by the upper controller 55 that has not detected a fault of the first electricity storage device pack 10 up to step S19. For example, the command unit 55b of the upper controller 55 may send a normal start-up command to the lower controller 52. The lower controller 52 may receive the normal start-up command via the communication unit 52a and start the start-up of the second electricity storage device pack 20.

[0037] After the fault diagnosis of the first power storage device pack 10, the command unit 52b of the lower-level controller 52 controls the positive electrode relay 22, the negative electrode relay 23, and the pre-charge relay 24b of the second power storage device pack 20 to the closed state in a predetermined order. At this time, the second power storage device pack 20 is not diagnosed for a fault.

[0038] In step S20, the command unit 52b instructs the negative electrode relay 23 to be closed. In step S21, the command unit 52b instructs the pre-charge relay 24b to be closed. In step S22, the command unit 52b instructs the positive electrode relay 22 to be closed. In step S23, the command unit 52b instructs the pre-charge relay 24b to be open. This starts up the second electricity storage device pack 20.

[0039] In the above-described embodiment, after the first electricity storage device pack 10 has been started up and the diagnostic process has been performed, the diagnostic process is not performed when the second electricity storage device pack 20 is started up. This reduces the startup time of the electricity storage device system 1.

[0040] Fig. 5 is a flowchart showing the processing executed by the controller 50 when shutting down the power storage device system 1. As shown in Fig. 4 and Fig. 5, when shutting down the power storage device system 1 after starting it up an odd number of times, the power storage device pack 20 is shut down and then the power storage device pack 10 is shut down.

[0041] In step S31, the command unit 52b issues a command to open the positive electrode relay 22 of the second electricity storage device pack 20. In step S32, the command unit 52b issues a command to open the negative electrode relay 23. This completes the shutdown of the second electricity storage device pack 20.

[0042] In step S33, the command unit 51b instructs the positive electrode relay 12 of the first power storage device pack 10 to be in an open state. In step S34, the determination unit 51c determines whether or not the positive electrode relay 12 has a closed-state fault, based on the voltage of the power storage device 11 acquired by the acquisition unit 51d. If the positive electrode relay 12 does not have a closed-state fault (if it is normal), the connection between the power storage device 11 and the load 60 is interrupted when the positive electrode relay 12 is set to the open state. Therefore, the voltage of the power storage device 11 drops after the positive electrode relay 12 is set to the open state. If the positive electrode relay 12 has a closed-state fault, the power storage device 11 and the load 60 remain connected by the positive electrode relay 12 with the closed-state fault and the negative electrode relay 13. If the voltage of the power storage device 11 does not drop after the positive electrode relay 12 is set to the open state, the determination unit 51c determines that the positive electrode relay 12 has a closed-state fault. In this case, the upper controller 55 is notified that the positive relay 12 has an open fault.

[0043] In step S35, the command unit 51b issues a command to open the negative electrode relay 13 of the first electricity storage device pack 10. This completes the shutdown of the first electricity storage device pack 10. Once the shutdown of the first electricity storage device pack 10 and the second electricity storage device pack 20 is complete, the change process S2 (see FIG. 2) is carried out.

[0044] <Change process S2> The change process S2 is a process for changing the power storage device pack that will be the target of fault diagnosis at the next startup. The timing at which the change process S2 is performed is not particularly limited. The change process S2 may be performed, for example, during startup of the power storage device system 1, after startup of the power storage device system 1, during shutdown of the power storage device system 1, or after shutdown of the power storage device system 1. The order of fault diagnosis may be predetermined in the controller 50 (in this embodiment, the storage unit 55a of the upper controller 55), and the power storage device pack that will be the target of fault diagnosis may be read in as appropriate when the power storage device system 1 is started up.

[0045] The controller 50 (in this embodiment, the memory unit 55a of the upper controller 55) stores the "number of startups" of the electricity storage device system 1. After the startup of the electricity storage device system 1 is completed, "1" is added to the stored "number of startups." This allows the controller 50 to recognize that the next startup will be an even-numbered startup. At the next startup, the second electricity storage device pack 20 will be the target of fault diagnosis. Note that fault diagnosis at the even-numbered startup is performed by the same process as fault diagnosis at the odd-numbered startup. Since fault diagnosis at the even-numbered startup can be performed by appropriately replacing the fault diagnosis process at the odd-numbered startup described above, a detailed description will be omitted.

[0046] Incidentally, when starting up an electricity storage device system including a plurality of electricity storage device packs, a fault in the relay of the electricity storage device pack may be diagnosed. During the fault diagnosis, it takes time to start up due to the time it takes to open and close the relay and to determine whether or not there is a fault when the relay is opened and closed. If a fault in the relay is diagnosed for all of the plurality of electricity storage device packs, it may take a long time to start up the electricity storage device system.

[0047] In the above-described embodiment, the relay fault diagnosis method is a relay fault diagnosis method for the power storage device system 1 including a plurality of power storage device packs 10, 20. The relay fault diagnosis method is executed by the controller 50. The relay fault diagnosis method includes a diagnostic process S1 and a change process S2. In the diagnostic process S1, a fault is diagnosed in the relays of some of the plurality of power storage device packs 10, 20 when the power storage device system 1 is started up. In the change process S2, the power storage device pack to be diagnosed is changed. In the diagnostic process S1, only some of the power storage device packs included in the power storage device system 1 are diagnosed for faults, thereby reducing the time required for the fault diagnosis. As a result, the time required for startup of the power storage device system 1 is reduced. Furthermore, in the change process S2, the power storage device pack to be diagnosed for faults at the next startup is changed, so that the plurality of power storage device packs 10, 20 are sequentially diagnosed for faults over multiple uses. This makes it easy to achieve both a reduction in the startup time of the power storage device system 1 and inspection of the power storage device system 1.

[0048] In the above-described embodiment, the power storage device pack to be diagnosed for failure is changed depending on the number of startups. As a result, in the change process S2, the power storage device pack to be diagnosed for failure is changed so that some of the power storage device packs diagnosed for failure in the diagnosis process S1 (in this embodiment, the first power storage device pack 10) will not be diagnosed for failure the next time the power storage device system 1 is started up. As a result, the power storage device packs to be diagnosed for failure are not consecutive at each startup, making it easier to inspect all the power storage device packs 10, 20 included in the power storage device system 1 evenly.

[0049] In the above-described embodiment, the power storage device pack 10 and the power storage device pack 20 are alternately diagnosed for faults. In the change process S2, the power storage device pack to be diagnosed for faults is changed according to a predetermined order of fault diagnosis. This prevents the power storage device packs to be diagnosed for faults from being consecutive at each startup. Furthermore, the power storage devices 11, 21 included in the power storage device system 1 can be more evenly inspected.

[0050] In the above-described embodiment, the controller 50 executes the diagnostic process S1 by switching the relay of one of the positive and negative electrode relays 12 and 13, which are currently open, to a closed state (step S14) for the power storage device pack 10 (negative electrode relay 13). After switching the relay of one of the positive electrode relays (negative electrode relay 13) to a closed state, the controller 50 executes a process by which the relay of the other electrode (positive electrode relay 12) is switched to a closed state (step S17). The controller 50 executes processes (steps S16 and S19) for diagnosing faults in the positive electrode relay 12 and the negative electrode relay 13 based on the voltage of the power storage device 11 of the power storage device pack 10 detected by the voltage sensor 15. This diagnostic process S1 makes it possible to diagnose relay faults in the power storage device pack 10 in synchronization with startup of the power storage device pack 10. As a result, the time required for relay fault diagnosis is reduced. Note that the relay opening and closing process in the diagnostic process S1 is not limited to the above-described form. The timing of switching from the open state to the closed state may be reversed between the positive relay 12 and the negative relay 13.

[0051] In the above-described embodiment, the controller 50 includes a host controller 55 and lower controllers 51 and 52. The host controller 55 transmits an inspection command to the lower controllers 51 and 52 of the power storage device pack to be diagnosed for a fault. The host controller 55 also changes the power storage device pack to be diagnosed as appropriate. The lower controllers 51 and 52 diagnose relay faults in the respective power storage device packs 10 and 20. The processes executed by the host controller 55 and the lower controllers 51 and 52 are separate. This eliminates the need for processes to synchronize the lower controllers 51 and 52. Furthermore, this eliminates the need for wiring or the like for transmitting and receiving information between the lower controllers 51 and 52. As a result, the processes executed by the entire controller 50 can be simplified. Furthermore, the time required for fault diagnosis can be shortened.

[0052] The change process S2 for changing the power storage device pack to be diagnosed is not limited to the above-described embodiment. In the above-described embodiment, the multiple power storage device packs 10, 20 are repeatedly diagnosed for failure at the same frequency at each startup, but the frequency of the failure diagnosis may be different. If the power storage device system includes multiple power storage device packs with different degrees of deterioration, for example, those manufactured at different times, the power storage device pack to be diagnosed for failure may be determined according to the degree of deterioration. In the change process, the power storage device pack to be diagnosed for failure at the next startup may be determined so that the more deteriorated the power storage device pack, the more frequently it will be diagnosed for failure. In the change process S2, the power storage device pack to be diagnosed for failure at the next startup may be determined randomly.

[0053] In the change process S2, the power storage device pack to be diagnosed may be changed based on the voltage of the power storage device (or cell) included in the power storage device system. The power storage device pack to be diagnosed may be changed based on the total voltage of each of the multiple power storage device packs connected in parallel. In this case, in the change process S2, the power storage device pack with the highest total voltage may be selected as the target of the fault diagnosis. Also, the power storage device pack to be diagnosed may be changed based on the maximum voltage of the cells included in the multiple power storage device packs. In this case, in the change process S2, the power storage device pack including the cell with the highest voltage may be selected as the target of the fault diagnosis. Also, the power storage device pack to be diagnosed may be changed based on the minimum voltage of the cells included in the multiple power storage device packs. In this case, in the change process S2, the power storage device pack including the cell with the lowest voltage may be selected as the target of the fault diagnosis. By changing the power storage device pack that is the target of the fault diagnosis based on the voltage of the power storage device included in the power storage device system, faults in the relays of the power storage device packs can be easily diagnosed early.

[0054] Furthermore, the diagnostic process S1 does not necessarily have to be executed at every startup. For example, if a predetermined interval has elapsed since the last diagnostic process S1 when the power storage device system 1 was started, the diagnostic process S1 may be executed. If a predetermined interval has not elapsed since the last diagnostic process S1 when the power storage device system 1 was started, the diagnostic process S1 may not be executed. The interval used as a reference for determining whether or not to execute the diagnostic process S1 may be determined based on the date and time of the startup interval. The reference interval may be stored, for example, in the storage unit 55a of the upper controller 55. The storage unit 55a may store the date and time when the diagnostic process S1 was last executed. If the difference between the date and time when the diagnostic process S1 was last executed and the current date and time when the power storage device system 1 is about to be started is equal to or greater than the reference interval, the command unit 55b of the upper controller 55 may send an inspection command to the lower controllers 51 and 52 to execute the diagnostic process S1.

[0055] In the above-described embodiment, the power storage device system 1 includes two power storage device packs 10, 20. However, the present invention is not limited to this. The power storage device system may include three or more power storage device packs. In the diagnostic process, faults in the relays of at least two or more power storage device packs (but less than the number of power storage device packs included in the power storage device system) may be diagnosed. This makes it possible to diagnose many power storage device packs with fewer startups. As a result, the time required to diagnose faults in all of the power storage device packs included in the power storage device system can be shortened.

[0056] The relay fault diagnosis method exemplified here may be realized by a program executed by a controller, or may be configured as a computer system including a memory (e.g., storage unit 55a of host controller 55) that stores the program and one or more processors that can execute the program stored in the memory.

[0057] The technology disclosed herein has been described in various ways. Unless otherwise specified, the embodiments and the like described herein do not limit the present invention. Furthermore, the technology disclosed herein can be modified in various ways, and as long as no particular problems arise, each component and each process described herein can be omitted or combined as appropriate. Furthermore, this specification includes the disclosures described in the following sections.

[0058] Section 1: A relay fault diagnosis method for an electric storage device system including a plurality of electric storage device packs, executed by a controller, comprising: a diagnostic process for diagnosing faults in relays of some of the plurality of power storage device packs when the power storage device system is started up; A change process for changing the power storage device pack that is the target of the fault diagnosis. Including, Relay fault diagnosis method.

[0059] Section 2: Item 1. A relay fault diagnosis method according to Item 1, wherein the change process changes the storage device packs to be subject to fault diagnosis so that the part of the storage device packs diagnosed for faults in the diagnosis process will not be subject to fault diagnosis the next time the storage device system is started.

[0060] Section 3: the controller stores an order of fault diagnosis for the plurality of power storage device packs; 3. The relay fault diagnosis method according to item 1 or 2, wherein the change process changes the power storage device pack that is the target of fault diagnosis in accordance with the order.

[0061] Section 4: the electricity storage device system includes three or more electricity storage device packs, 4. The relay fault diagnosis method according to any one of items 1 to 3, wherein the diagnostic process diagnoses faults in the relays of at least two power storage device packs.

[0062] Section 5: Each of the plurality of electricity storage device packs comprises: an electricity storage device having a positive electrode and a negative electrode; a positive electrode relay connected to a positive electrode side of the power storage device; a negative electrode relay connected to the negative electrode side of the power storage device; Equipped with the controller controls opening and closing of the positive electrode relay and the negative electrode relay; When the power storage device system is started up, the positive electrode relay and the negative electrode relay of the part of the power storage device packs are in an open state, The diagnostic process includes the steps of: A process of switching the relay of either one of the positive electrode relay and the negative electrode relay, which are in an open state, to a closed state; a process of switching the relay of one of the poles to a closed state and then switching the relay of the other pole to a closed state; a process of diagnosing a fault in the positive electrode relay and the negative electrode relay based on the voltage of the power storage device in the part of the power storage device packs; 5. A relay fault diagnosis method according to any one of items 1 to 4, comprising:

[0063] Item 6: 6. A program that causes a controller to execute the relay fault diagnosis method according to any one of items 1 to 5.

[0064] Section 7: A memory for storing the program according to item 6; one or more processors capable of executing the program stored in the memory; A computer system comprising:

[0065] Section 8: a plurality of power storage device packs connected in parallel; Controller and Equipped with The controller a process of diagnosing a fault in a relay of some of the plurality of power storage device packs at startup; A process to change the power storage device pack to be diagnosed every time the device is started. The power storage device system is configured to execute the above. [Explanation of symbols]

[0066] 1. Energy storage device system 10,20 Energy storage device pack 11,21 Energy storage devices 12,22 Positive relay 13,23 Negative relay 14,24 Precharge circuit 14a, 24a Precharge resistor 14b, 24b Precharge relay 15,25 Voltage sensor 50 Controllers 51,52 Lower Controller 51a,52a Communication Department 51b,52b Command section 51c,52c Judgment section 51d,52d Acquisition Department 55 Upper controller 55a Memory section 55b Command Department 55c Judgment section 60 load

Claims

1. A relay fault diagnosis method for an electric storage device system including a plurality of electric storage device packs, executed by a controller, comprising: a diagnostic process for diagnosing faults in relays of some of the plurality of power storage device packs when the power storage device system is started up; A change process for changing the power storage device pack that is the target of the fault diagnosis. Including, Relay fault diagnosis method.

2. 2. The relay fault diagnosis method according to claim 1, wherein the change process changes the electric storage device packs to be subjected to fault diagnosis so that the part of the electric storage device packs diagnosed for fault in the diagnosis process will not be subjected to fault diagnosis at the next startup of the electric storage device system.

3. the controller stores an order of fault diagnosis for the plurality of power storage device packs; The relay fault diagnosis method according to claim 1 , wherein the change process changes the power storage device pack to be diagnosed in accordance with the order.

4. the electricity storage device system includes three or more electricity storage device packs, The relay fault diagnosis method according to claim 1 , wherein the diagnostic process diagnoses faults in the relays of at least two power storage device packs.

5. Each of the plurality of electricity storage device packs comprises: an electricity storage device having a positive electrode and a negative electrode; a positive electrode relay connected to a positive electrode side of the power storage device; a negative electrode relay connected to the negative electrode side of the power storage device; Equipped with the controller controls opening and closing of the positive electrode relay and the negative electrode relay; When the power storage device system is started up, the positive electrode relay and the negative electrode relay of the part of the power storage device packs are in an open state, The diagnostic process includes the steps of: A process of switching the relay of either one of the positive electrode relay and the negative electrode relay, which are in an open state, to a closed state; a process of switching the relay of one of the poles to a closed state and then switching the relay of the other pole to a closed state; a process of diagnosing a fault in the positive electrode relay and the negative electrode relay based on the voltage of the power storage device in the part of the power storage device packs; 5. The relay fault diagnosis method according to claim 1, further comprising:

6. A program that causes a controller to execute the relay fault diagnosis method according to any one of claims 1 to 4.

7. a memory for storing the program according to claim 6; one or more processors capable of executing the program stored in the memory; A computer system comprising:

8. a plurality of power storage device packs connected in parallel; Controller and Equipped with The controller a process of diagnosing a fault in a relay of some of the plurality of power storage device packs at startup; A process to change the power storage device pack to be diagnosed every time the device is started. The power storage device system is configured to execute the above.

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