Battery control system, work vehicle, and control method

Abstract

A battery control system 1 comprises a plurality of battery packs 10 connected in parallel and a controller 50. The controller 50 stores, in a storage unit 51, a battery pack 10 to be first connected to a load at the next start-up. At the time of starting, the stored battery pack 10 is first connected to the load. After connection processing of the stored battery pack 10 is performed, a failure of the battery pack 10 on which the connection processing has been performed is detected first. When no failure is detected, a battery pack 10 different from the battery pack 10 that is first connected to the load at the latest start-up is stored in the storage unit 51 as a battery pack 10 to be first connected to the load at the next start-up. When a failure is detected, a battery pack 10 that is different from the battery pack 10 first connected to the load at the latest start-up and is other than the battery pack 10 in which the failure has been detected is stored in the storage unit 51 as a battery pack 10 to be first connected to the load at the next start-up.

Description

Battery control system, work vehicle, and control method

[0001] The present disclosure relates to a battery control system, a work vehicle, and a control method.

[0002] Patent document 1 discloses a battery monitoring device that is installed in multiple battery devices and includes a relay that connects the battery to a load and a precharge relay that prevents inrush current from flowing from the battery to the load, and that monitors the status of the battery devices.

[0003] JP 2019-164897 A

[0004] Each battery pack is provided with a precharge connection member such as a precharge relay. When multiple battery packs are connected in parallel, the precharge connection member of one of the battery packs is turned on at startup to precharge the capacitor on the load side (secondary side).

[0005] However, if the precharge connector of the same battery pack is turned on to perform precharge every time the battery pack is started up, there is a risk that a malfunction in the precharge connector of another battery pack may go unnoticed.

[0006] According to the present disclosure, there is provided a battery control system including a plurality of battery packs connected in parallel and a controller controlling the battery packs, wherein the controller stores in a memory unit the battery pack that will be first connected to a load at the next startup, connects the stored battery pack to the load first at startup, and after executing a connection process for the stored battery pack, detects a fault in the battery pack that first executed the connection process, and if a fault in the battery pack that first executed the connection process is not detected, stores in the memory unit a battery pack different from the battery pack that was first connected to the load at the most recent startup as the battery pack that will be first connected to the load at the next startup, and if a fault is detected in the battery pack that first executed the connection process, stores in the memory unit a battery pack other than the battery pack in which a fault was detected that is different from the battery pack that was first connected to the load at the most recent startup as the battery pack that will be first connected to the load at the next startup.

[0007] According to the present disclosure, there is provided a work vehicle including the above-described battery control system and a work implement.

[0008] According to the present disclosure, there is provided a control method including: storing in a memory unit, among a plurality of battery packs connected in parallel, a battery pack that will be first connected to a load at the next startup; connecting the stored battery pack to the load first at startup; executing a connection process for the stored battery pack; detecting a fault in the battery pack that first executed the connection process; if a fault in the battery pack that first executed the connection process is not detected, storing in the memory unit a battery pack different from the battery pack that was first connected to the load at the most recent startup as the battery pack that will be first connected to the load at the next startup; and if a fault is detected in the battery pack that first executed the connection process, storing in the memory unit a battery pack other than the battery pack in which the fault was detected that is different from the battery pack that was first connected to the load at the most recent startup as the battery pack that will be first connected to the load at the next startup.

[0009] According to the present disclosure, a failure in a battery pack can be appropriately determined.

[0010] Fig. 1 is a block diagram showing an example of a battery control system according to an embodiment. Fig. 2 is a block diagram showing an example of a battery pack according to an embodiment. Fig. 3 is a block diagram showing a controller of the battery control system according to an embodiment. Fig. 4 is a block diagram showing a computer system according to an embodiment. Fig. 5 is a flowchart showing a battery control method according to an embodiment.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings, but the present disclosure is not limited thereto. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0012] [Embodiment] <Battery Control System> Fig. 1 is a block diagram showing an example of a battery control system according to an embodiment. Fig. 2 is a block diagram showing an example of a battery pack according to an embodiment. In the embodiment, the battery control system 1 is applied to a work vehicle powered by a battery. The battery control system 1 includes a plurality of battery packs 10 connected in parallel, a power distribution unit (PDU) 20, and a controller 50.

[0013] The battery control system 1 includes a plurality of battery packs connected in parallel. In the embodiment, the battery control system 1 includes a first battery pack 10 １ and the second battery pack 10 ２ The first battery pack 10 １ and the second battery pack 10 ２ are electrically connected in parallel. １ and the second battery pack 10 ２ When there is no particular need to distinguish between the battery packs 10 and the battery pack 11, the battery packs 10 will be described as the battery pack 10. The number of battery packs 10 may be plural and is not limited to two.

[0014] The battery pack 10 includes a battery 11, a negative electrode main connection member 12, a precharge connection member 15, a resistor 16, and a positive electrode main connection member (main connection member) 17. The battery pack 10 is electrically connected to a power distribution device 20 via a positive electrode terminal 10a and a negative electrode terminal 10b.

[0015] An identification number is assigned to the battery pack 10. In the embodiment, the battery packs 10 are assigned consecutive numbers.

[0016] The battery 11 has a plurality of battery cells electrically connected in series. A disconnect switch (not shown) may be electrically connected to the positive electrode side of the battery 11. A negative electrode main connecting member 12 is electrically connected to the negative electrode side of the battery 11.

[0017] The negative main connection member 12 is electrically connected to the negative side of the battery 11. The negative main connection member 12 is disposed between the negative electrode of the battery 11 and the terminal 10b. The negative main connection member 12 may be any device capable of switching the main circuit in the battery pack 10 between ON and OFF, such as a relay, a contactor, an IGBT (Insulated Gate Bipolar Transistor), or a switching element. The negative main connection member 12 is controlled to be turned ON and OFF by commands from the controller 50. The negative main connection member 12 is turned ON together with the precharge connection member 15 when precharging is performed.

[0018] The precharge connection member 15 switches the precharge circuit using the battery 11 between ON and OFF. The precharge connection member 15 is electrically connected to the positive electrode side of the battery 11. The precharge connection member 15 is electrically connected in parallel with the positive electrode main connection member 17. The precharge connection member 15 is electrically connected between the positive electrode side of the battery 11 and the resistor 16. The precharge connection member 15 may be any device capable of switching the precharge circuit in the battery pack 10 between ON and OFF, such as a relay, contactor, IGBT, or switching element. The precharge connection member 15 is controlled to be ON or OFF by commands from the controller 50. The precharge connection member 15 is turned ON when precharging is performed. The precharge connection member 15 is turned OFF after precharging is completed.

[0019] The resistor 16 is electrically connected to the positive electrode side of the battery 11. The resistor 16 is electrically connected in series with the precharge connection member 15. The resistor 16 is electrically connected in parallel with the positive electrode main connection member 17. The resistor 16 is disposed between the precharge connection member 15 and the terminal 10a.

[0020] The positive electrode main connection member 17 is electrically connected to the positive electrode side of the battery 11. The positive electrode main connection member 17 is electrically connected in parallel with a precharge circuit composed of the precharge connection member 15 and the resistor 16. The positive electrode main connection member 17 is electrically connected between the positive electrode side of the battery 11 and the terminal 10a. The positive electrode main connection member 17 may be any device that can switch the circuit in the battery pack 10 between ON and OFF, such as a relay, contactor, IGBT, or switching element. The positive electrode main connection member 17 is controlled to be ON or OFF by commands from the controller 50. The positive electrode main connection member 17 is turned OFF when precharge is performed. The positive electrode main connection member 17 is turned ON after precharge is completed.

[0021] The power distribution device 20 distributes the power supplied from the battery pack 10 to the load side. The power distribution device 20 is electrically connected to the battery pack 10, the on-board charger 43, and the inverter 45.

[0022] The charging port 42 is electrically connected to an on-board charger 43 .

[0023] The on-board charger 43 is a charger mounted on the vehicle and is electrically connected to the terminals 20 e and 20 f of the power distribution device 20 .

[0024] The inverter 45 is electrically connected to the power distribution device 20 via terminals 20g and 20h. A motor 46, which is a load, is connected to the inverter 45. The inverter 45 includes a capacitor (not shown).

[0025] <Controller> Fig. 3 is a block diagram showing a controller of the battery control system according to the embodiment. The controller 50 controls the battery pack 10. The controller 50 is electrically connected to the battery pack 10, the power distribution device 20, the on-board charger 43, and the inverter 45. The controller 50 includes a numerical calculation device (processor) such as a CPU (Central Processing Unit). The controller 50 is configured with one or more numerical calculation devices.

[0026] The functions implemented by the controller 50 will be described.

[0027] The controller 50 has the following functions: stores in a memory unit 51 the battery pack 10 to be connected to the load first at the next startup; connects the stored battery pack 10 to the load first at startup; detects a fault in the battery pack 10 that first executed the connection process after executing the connection process for the stored battery pack 10; if no fault is detected in the battery pack 10 that first executed the connection process, stores in the memory unit 51 a battery pack 10 different from the battery pack 10 that was first connected to the load at the most recent startup as the battery pack 10 to be connected to the load first at the next startup; if a fault is detected in the battery pack 10 that first executed the connection process, stores in the memory unit 51 a battery pack 10 other than the battery pack 10 that was detected to be faulty and different from the battery pack 10 that was first connected to the load at the most recent startup as the battery pack 10 to be connected to the load first at the next startup.

[0028] The controller 50 has a function of connecting the precharge connection member 15 of the battery pack 10 to the battery pack 10 that is to be connected to the load first, performing precharge, and then connecting the battery pack 10 to the load.

[0029] The controller 50 has the following functions: if no failure is detected in the battery pack 10 that first executed the connection process, the controller 50 performs the connection process on all battery packs 10 other than the battery pack 10 that first executed the connection process; if a failure is detected in the battery pack 10 that first executed the connection process, the controller 50 performs the connection process on one of the battery packs 10 other than the battery pack 10 that first executed the connection process.

[0030] The controller 50 has the function of storing in the memory unit 51, if no failure is detected in the battery pack 10 that first performed the connection process, the battery pack 10 that has the number next to the number of the battery pack 10 that was first connected to the load at the most recent startup as the battery pack 10 that will be first connected to the load at the next startup.

[0031] For example, each function of the controller 50 may be included in a single main controller, in which case the single main controller performs processing to control each battery pack.

[0032] The functions of the controller 50 may be distributed among, for example, a battery controller disposed in each battery pack and a main controller that controls them. In this case, the battery controllers and the main controller perform processing in cooperation with each other.

[0033] The functions of the controller 50 may be allocated to, for example, one of the battery controllers arranged in each battery pack, which functions as a main controller that controls the other battery controllers. In this case, the one battery controller functioning as the main controller performs processing to control each battery pack.

[0034] In the following description, as an example, it is assumed that each function of the controller 50 is provided by one main controller.

[0035] The controller 50 includes a storage unit 51 , a connection processing unit 54 , and a failure detection unit 55 .

[0036] The storage unit 51 stores information such as an identification number (number) indicating the battery pack 10 that will be first connected to a load at the next startup. When the connection process for the battery pack 10 at startup is completed, the storage unit 51 updates and stores information such as the identification number indicating the battery pack 10 that will be first connected to a load at the next startup.

[0037] A different battery pack is designated each time the device is started as the battery pack to be first connected to the load at startup. For example, one of a plurality of battery packs is designated in order as the battery pack to be first connected to the load at startup. The battery pack to be first connected to the load at startup is a battery pack different from the battery pack designated first at the most recent startup.

[0038] The storage unit 51 may store information such as an identification number indicating the battery pack 10 in which a failure has been detected by the failure detection unit 55. The battery pack 10 in which a failure has been detected is excluded from the battery packs 10 that will be first connected to a load at the next startup until replacement or repair is completed. In other words, the battery pack 10 is not stored in the storage unit 51 as the battery pack 10 that will be first connected to a load at the next startup.

[0039] If no failure is detected in the battery pack 10 that first executed the connection process, the memory unit 51 stores a battery pack 10 different from the battery pack 10 that was first connected to the load at the most recent startup as the battery pack 10 that will be first connected to the load at the next startup.

[0040] In an embodiment, if no fault is detected in the battery pack 10 that first performed the connection process, the memory unit 51 stores in the memory unit 51 the battery pack 10 numbered with the number next to the number of the battery pack 10 that was first connected to the load at the most recent startup as the battery pack 10 that will be first connected to the load at the next startup.

[0041] When a failure is detected in the battery pack 10 that first executed the connection process, the memory unit 51 stores in the memory unit 51 a battery pack 10 other than the battery pack 10 in which the failure was detected, which is different from the battery pack 10 that was first connected to the load at the most recent startup, as the battery pack 10 to be first connected to the load at the next startup.

[0042] At the time of startup, the connection processing unit 54 performs connection processing for the battery pack 10 to be connected to the load first, which is stored in the storage unit 51. At the time of startup, the connection processing unit 54 connects the battery pack 10 to the load first, which is stored in the storage unit 51, to the load first, in other words, before performing connection processing for the other battery packs 10.

[0043] If this is the first connection process at startup, in other words, if precharging is not complete, the connection processing unit 54 performs connection processing with precharging for the battery pack 10 that is to be connected to the load first, as stored in the memory unit 51. The connection processing unit 54 connects the precharge connection member 15 of the battery pack 10 to the battery pack 10 that is to be connected to the load first, performs precharging, and then connects the battery pack 10 to the load. The connection processing unit 54 turns on the negative main connection member 12 and the precharge connection member 15 while keeping the positive main connection member 17 of the battery pack 10 that is to be connected to the load first in the OFF state. The connection processing unit 54 determines that precharging is complete when the voltages at point A1 on the positive side of the precharge connection member 15 and point A2 on the terminal 10a side of the resistor 16 are equal, and when the voltages at points B1 and B2 across the negative main connection member 12 are equal. The connection processing unit 54 determines that precharging is complete when the difference between the total voltage on the battery 11 side and the total voltage on the load side remains smaller than the precharge completion determination voltage for a determination time. When determining that precharging is complete, the connection processing unit 54 turns off the precharge connection member 15 and turns on the positive electrode main connection member 17.

[0044] If no fault is detected in the battery pack 10 that first executed the connection process, the connection processing unit 54 performs the connection process on all battery packs 10 other than the battery pack 10 that first executed the connection process. The connection processing unit 54 turns on the negative electrode main connecting member 12 and the positive electrode main connecting member 17 of all battery packs 10 other than the battery pack 10 that first connects to the load.

[0045] When a failure is detected in the battery pack 10 that first executed the connection process, the connection processing unit 54 performs connection processing on one of the battery packs 10 other than the battery pack 10 that first executed the connection process. The connection processing unit 54 performs connection processing with precharging on one of the battery packs 10 other than the battery pack 10 that is first connected to the load. The connection processing unit 54 turns on the negative main connection member 12 and the precharge connection member 15 of one of the battery packs other than the battery pack 10 that is first connected to the load, while keeping the positive main connection member 17 OFF.

[0046] The fault detection unit 55 detects a fault in the battery pack 10 that first executed the connection process after executing the connection process in the battery pack 10 that is connected to the load first. The fault detection unit 55 determines a fault in the precharge connection member 15 in the battery pack 10 after executing the connection process involving precharge. The fault detection unit 55 determines whether or not there is an abnormality in the precharge in the battery pack 10 after executing the connection process involving precharge. The fault detection unit 55 determines whether or not precharge in the battery pack 10 was completed normally. For example, if the total voltage on the load side remains below a predetermined value for a predetermined period of time, the fault detection unit 55 determines that precharge was not completed normally and that there is an abnormality, in other words, that there is a fault.

[0047] FIG. 4 is a block diagram showing a computer system according to an embodiment. The controller 50 includes a computer system 1000. The computer system 1000 includes a processor 1001 such as a CPU, a main memory 1002 including a nonvolatile memory such as a read-only memory (ROM) and a volatile memory such as a random access memory (RAM), a storage 1003, and an interface 1004 including an input / output circuit. The functions of the controller 50 described above are stored as a program in the storage 1003. The processor 1001 reads the program from the storage 1003, loads it into the main memory 1002, and executes the above-described processing in accordance with the program. The program may be distributed to the computer system 1000 via a network.

[0048] <Control Method> Figure 5 is a flowchart showing a battery control method according to this embodiment. For example, when the key of a work vehicle is turned on, the battery control system 1 is started. When the battery control system 1 is started, the processing of the flowchart shown in Figure 5 is started and the control method is executed.

[0049] The controller 50 causes the connection processing unit 54 to transmit a connection command to the battery pack 10 that is to be connected to the load first and that is stored in the storage unit 51, to execute connection processing (step ST11).

[0050] The controller 50 causes the connection processing unit 54 to turn on the precharge connection member 15 of the battery pack 10 specified in the connection command (step ST12). When step ST12 is executed after step ST11, the battery pack 10 specified in the connection command is the battery pack 10 to be connected to the load first. When step ST12 is executed after step ST17, the battery pack 10 specified in the connection command is the battery pack 10 to be connected next. The controller 50 causes the connection processing unit 54 to turn on the negative main connection member 12 and precharge connection member 15 of the battery pack 10 to be connected first or next, while keeping the positive main connection member 17 OFF. When the negative main connection member 12 and precharge connection member 15 of the battery pack 10 to be connected first or next are turned on, the capacitor of the inverter 45 is precharged by the precharge circuit.

[0051] The controller 50 determines whether the battery pack 10 that was connected in step ST12 has successfully completed precharging (step ST13). More specifically, the controller 50 determines that precharging has successfully completed when the connection processing unit 54 determines that the voltages at point A1 on the positive side of the precharge connection member 15 and point A2 on the terminal 10a side of the resistor 16 are equal, and also when the voltages at points B1 and B2 across the negative main connection member 12 are equal. The controller 50 determines that precharging has successfully completed when the connection processing unit 54 determines that the difference between the total voltage on the battery 11 side and the total voltage on the load side of the battery pack 10 that was connected in step ST12 remains smaller than the precharge completion determination voltage for a determination time. If the controller 50 determines that precharging has successfully completed precharging (Yes in step ST13), the controller 50 proceeds to step ST14. If the controller 50 does not determine that the precharge has been completed normally (No in step ST13), the controller 50 proceeds to step ST17.

[0052] When it is determined that the precharge has been completed normally (Yes in step ST13), the controller 50 causes the connection processing unit 54 to turn on the main connection member (step ST14). More specifically, the controller 50 causes the connection processing unit 54 to turn off the precharge connection member 15 of the battery pack 10 that was connected in step ST12, and turn on the positive main connection member 17.

[0053] The controller 50 causes the connection processing unit 54 to execute the connection process for the remaining battery packs (step ST15). More specifically, the controller 50 causes the connection processing unit 54 to turn on the negative electrode main connecting members 12 and the positive electrode main connecting members 17 of the battery packs 10 that have not been connected in step ST12, in other words, the remaining battery packs 10.

[0054] The controller 50 stores in the storage unit 51 the battery pack 10 to be first connected to the load at the next startup (step ST16). If no failure is detected in the battery pack 10 that first executed the connection process, the controller 50 stores in the storage unit 51 a battery pack 10 different from the battery pack 10 that was first connected to the load at the most recent startup as the battery pack 10 to be first connected to the load at the next startup. If a failure is detected in the battery pack 10 that first executed the connection process, the controller 50 stores in the storage unit 51 a battery pack 10 other than the battery pack 10 in which the failure was detected, that is different from the battery pack 10 that was first connected to the load at the most recent startup, as the battery pack 10 to be first connected to the load at the next startup.

[0055] If it is not determined that the precharge has been completed normally (No in step ST13), the controller 50 causes the connection processing unit 54 to send a connection command to the next battery pack to execute connection processing (step ST17).

[0056] After step ST17, the controller 50 executes the process of step ST12 again.

[0057] In this way, in step ST12, the positive main connection member 17 remains OFF, and the negative main connection member 12 and precharge connection member 15 are turned ON to form a precharge circuit. Because the resistor 16 is connected in series with the precharge connection member 15, a small current flows. The capacitor of the inverter 45, which is arranged on the load side, is charged (precharged) with a small current. In step ST14, the precharge connection member 15 of the battery pack 10 is turned OFF, and the positive main connection member 17 is turned ON to form a normal circuit.

[0058] The battery pack 10 that is first connected to the load at startup is different each time. In step ST13, the battery pack 10 used for precharging is checked for any malfunction. For this reason, the precharge connection members 15 of the multiple battery packs 10 are periodically checked for any malfunction.

[0059] <Effects> As described above, in the embodiment, the battery pack 10 that is first connected to the load at startup can be different each time. According to the embodiment, it is possible to periodically check whether or not there is a malfunction in the precharge connection members 15 of the plurality of battery packs 10. In the embodiment, it is possible to detect a malfunction in a battery pack after executing the connection process for the battery pack 10 that is first connected to the load at startup that is stored.

[0060] In the embodiment, the battery packs 10 other than the battery pack 10 in which a failure is detected are stored. According to the embodiment, it is possible to avoid using the battery pack 10 in which a failure is detected for precharging until it is replaced.

[0061] In the embodiment, the battery pack 10 that is to be connected to the load first at the time of startup can be connected to the precharge connection member 15 of the battery pack 10 to perform precharge, and then connected to the load. According to the embodiment, the inrush current flowing into the load at the time of startup can be suppressed.

[0062] In the embodiment, if no failure is detected in the battery pack 10 used for precharging, connection processing is executed for all battery packs 10 other than the battery pack 10 that executed the precharging. In the embodiment, if a failure is detected in the battery pack 10 used for precharging, connection processing is executed for one of the battery packs 10 other than the battery pack 10 that executed the precharging. According to the embodiment, if the battery pack 10 initially connected to the load is faulty and cannot be precharged, precharge can be executed using another battery pack 10.

[0063] In the embodiment, the battery pack 10 in which a fault has been detected can be prevented from being stored as a battery pack to be first connected to a load at the next startup until the battery pack 10 is replaced or repaired. According to the embodiment, the battery pack 10 in which a fault has been detected can be prevented from being used for precharging until the battery pack 10 is replaced.

[0064] In the embodiment, a failure of the precharge connection member can be detected as a failure of the battery pack 10 .

[0065] In an embodiment, if no fault is detected in the battery pack 10 that first performed the connection process, the battery pack 10 numbered with the number next to the number of the battery pack 10 that was first connected to the load at the most recent startup can be stored as the battery pack 10 that will be first connected to the load at the next startup.

[0066] In the above, there is no limitation on the order in which the precharge connection members 15 and the resistors 16 are connected, but the order in which the precharge connection members 15 and the resistors 16 are connected may be reversed.

[0067] In the above embodiment, the case where the invention is applied to a work vehicle has been described, but the invention is not limited to work vehicles.

[0068] <Modification> A case will be described in which the functions of the controller 50 are distributed between a battery controller disposed in each battery pack and a main controller that controls them. In this case, for example, the storage unit 51 is disposed in the main controller, and the fault detection unit 55 is disposed in the battery controller. The functions of the connection processing unit 54 are distributed between the main controller and the battery controller, and are implemented by their cooperation.

[0069] At startup, the connection processing unit 54 of the main controller transmits a connection request to the battery pack 10 to be connected to the load first, which is stored in the storage unit 51. The connection processing unit 54 of the main controller receives a failure detection result from the battery pack 10 that transmitted the connection request.

[0070] After connecting the battery pack 10 that was first connected to the load, the connection processing unit 54 of the main controller transmits connection requests to the remaining battery packs. More specifically, if the precharge of the battery pack 10 that was first connected to the load is successfully completed, the connection processing unit 54 of the main controller transmits connection requests to the remaining battery packs 10. If the precharge of the battery pack 10 that was first connected to the load is not successfully completed, the connection processing unit 54 of the main controller transmits a connection request to one of the remaining battery packs 10. Subsequent processing is the same as that performed after the first battery pack 10 is connected.

[0071] The connection processing unit 54 of the main controller functions as a command transmitting unit.

[0072] The connection processing unit 54 of the battery controller arranged in each battery pack 10 receives a connection request transmitted from the connection processing unit 54 of the main controller to that battery pack 10. The connection processing unit 54 of the battery controller performs connection processing in that battery pack 10 that has received the connection request. The connection processing unit 54 of the battery controller receives a failure detection result from that battery pack 10 that has executed connection processing.

[0073] In this modification, in step ST11, the connection processing unit 54 of the main controller transmits a connection request to the battery pack 10 stored in the memory unit 51 to be connected to the load first. In step ST12, the connection processing unit 54 of the battery controller turns on the precharge connection member 15 of the battery pack 10 that received the connection request. In step ST13, the fault detection unit 55 of the main controller determines whether or not there is a precharge abnormality in the battery pack 10. In step ST14, the connection processing unit 54 of the battery controller turns on the main connection member of the battery pack 10 that received the connection request. In step ST15, the connection processing unit 54 of the main controller transmits connection requests to the remaining battery packs. In step ST16, the main controller stores in the memory unit 51 the battery pack 10 that will be connected to the load first at the next startup. In step ST17, the connection processing unit 54 of the main controller transmits a connection request to the next battery pack.

[0074] 1... Battery control system, 10... Battery pack, 10a... Terminal, 10b... Terminal, 11... Battery, 12... Negative electrode main connection member, 15... Precharge connection member, 16... Resistor, 17... Positive electrode main connection member (main connection member), 20... Power distribution unit (PDU), 20a １ ...terminal, 20a ２ ...terminal, 20b １ ...terminal, 20b ２ ...terminal, 20c...terminal, 20d...terminal, 20e...terminal, 20f...terminal, 20g...terminal, 20h...terminal, 20i...terminal, 20j...terminal, 20k...terminal, 20m...terminal, 20n...terminal, 20p...terminal, 42...charging port, 43...on-board charger, 45...inverter, 46...motor, 50...controller, 51...memory unit, 54...connection processing unit, 55...fault detection unit.

Claims

1. A battery control system comprising a plurality of battery packs connected in parallel, and a controller for controlling the battery packs, wherein the controller: stores in a memory unit the battery pack to be connected to a load first at the next startup; connects the stored battery pack to the load first at startup; detects a fault in the battery pack that first executed the connection process after executing the connection process of the stored battery pack; if a fault in the battery pack that first executed the connection process is not detected, stores in the memory unit a battery pack different from the battery pack that was first connected to the load at the most recent startup as the battery pack to be connected to the load first at the next startup; if a fault is detected in the battery pack that first executed the connection process, stores in the memory unit a battery pack other than the battery pack in which the fault was detected, that is different from the battery pack that was first connected to the load at the most recent startup, as the battery pack to be connected to the load first at the next startup.

2. A battery control system as described in claim 1, further comprising: a precharge connection member connected to the battery of the battery pack and switching a circuit for precharging using the battery between ON and OFF, wherein the controller connects the precharge connection member of the battery pack to the battery pack that is to be connected to a load first, performs the precharge, and then connects the battery to the load.

3. The battery control system of claim 1, wherein the controller, if no failure is detected in the battery pack that first executed the connection process, performs connection processing on all of the battery packs other than the battery pack that first executed the connection process, and, if a failure is detected in the battery pack that first executed the connection process, performs connection processing on one of the battery packs other than the battery pack that first executed the connection process.

4. The battery control system according to claim 1, wherein the battery pack in which a failure has been detected is not stored as the battery pack to be first connected to the load at the next startup until replacement or repair is completed.

5. The battery control system according to claim 1, further comprising: a precharge connection member connected to the battery of the battery pack and switching a precharge circuit using the battery between ON and OFF, wherein a failure of the battery pack is a failure of the precharge connection member.

6. The battery control system of claim 1, wherein the battery packs are assigned numbers for identification, and when no failure is detected in the battery pack that first executed the connection process, the controller stores in the memory unit the battery pack numbered with the number next to the number of the battery pack that was first connected to the load at the most recent startup as the battery pack that will be first connected to the load at the next startup.

7. A work vehicle comprising: a battery control system according to any one of claims 1 to 6; and a work implement.

8. A control method comprising: storing in a memory unit, among multiple battery packs connected in parallel, the battery pack that will be first connected to a load at the next startup; connecting the stored battery pack to the load first at startup; executing a connection process for the stored battery pack, and then detecting a fault in the battery pack that first executed the connection process; if no fault is detected in the battery pack that first executed the connection process, storing in the memory unit a battery pack different from the battery pack that was first connected to the load at the most recent startup as the battery pack that will be first connected to the load at the next startup; if a fault is detected in the battery pack that first executed the connection process, storing in the memory unit a battery pack other than the battery pack in which the fault was detected, that is different from the battery pack that was first connected to the load at the most recent startup, as the battery pack that will be first connected to the load at the next startup.

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