Battery module and battery system

Abstract

To improve battery productivity.SOLUTION: A battery module 100 includes a battery pack 10, a first contactor 11, a second contactor 12, a pair of connection points 30, 40, a precharge circuit 13, and a service plug 14. The first contactor is connected in series to the battery pack from the positive electrode side of the battery pack. The second contactor is connected in series to the battery pack from the negative electrode side of the battery pack. The pair of connection points are provided at both ends of the first contactor, the battery pack, and the second contactor, which are connected in series. The precharge circuit is connected in parallel to one of the contactors. The service plug is provided between the pair of connection points, on the opposite pole side of the battery pack from the contactor to which the precharge circuit is connected in parallel. The service plug is connected in series to the other contactor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery module and a battery system. [Background technology]

[0002] International Publication WO 2012 / 168963 discloses a battery system having a first battery and a second battery connected in parallel, a first relay, a second relay, and a controller. The first relay is switched between an on state that allows charging and discharging of the first battery and an off state that prohibits charging and discharging of the first battery. The second relay is switched between an on state that allows charging and discharging of the second battery and an off state that prohibits charging and discharging of the second battery. The controller controls the on and off states of the first and second relays. The controller changes the order in which the first and second relays are turned on when charging and discharging the first and second batteries. This configuration is said to suppress deterioration of the first and second relays. In the battery system disclosed in the publication, a service plug is provided in each of the assembled batteries that constitute the first and second batteries. The service plug is provided at the middle position of the assembled batteries that are connected in series. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 168963 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors wish to further improve safety during maintenance. [Means for solving the problem]

[0005] The battery module disclosed herein includes a battery pack, a first contactor connected in series to the battery pack from the positive electrode side of the battery pack, a second contactor connected in series to the battery pack from the negative electrode side of the battery pack, a pair of connection points provided at both ends of the first contactor, the battery pack, and the second contactor connected in series and connected to an external load, a precharge circuit connected in parallel to one of the first and second contactors, the precharge circuit having a precharge resistor and a third contactor connected in series, and a service plug. The service plug is provided between the pair of connection points on the opposite pole side of the battery pack from the one contactor connected in parallel to the precharge circuit, and is connected in series to the other of the first and second contactors. Such a battery module is safer during maintenance. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram showing a battery system 1. As shown in FIG. [Diagram 2] FIG. 2 is a flowchart showing the process executed by the control device 50. [Diagram 3] FIG. 3 is a flowchart showing the process executed by the control device 50. [Figure 4] FIG. 4 is a schematic diagram showing the battery module 100A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, an embodiment of the technology disclosed herein will be described with reference to the drawings. The embodiment described herein is, of course, not intended to limit the present invention in particular. Each drawing is drawn typically and does not necessarily reflect the actual product. Furthermore, the same reference numerals are appropriately used for members and parts that perform the same function, and duplicated descriptions are appropriately omitted.

[0008] <Battery System 1> Fig. 1 is a schematic diagram showing a battery system 1. As shown in Fig. 1, the battery system 1 includes a battery module 100 and an external load 200. The battery module 100 is connected to the external load 200, such as a load of a vehicle (a drive device such as an electric motor) or an external power supply.

[0009] <Battery module 100> The battery module 100 includes a first system 110 and a second system 120 connected in parallel, and a control device 50. The battery module 100 includes a pair of connection points 30, 40 that are connected to an external load 200. In this embodiment, the first system 110 and the second system 120 are connected in parallel via the connection points 30, 40. The battery module 100 includes a voltage measuring device 60 that measures the voltage of the external load 200.

[0010] The first system 110 of the battery module 100 includes an assembled battery 10, a first contactor 11, a second contactor 12, a precharge circuit 13, and a service plug 14. A pair of connection points 30, 40 are located at both ends of the first contactor 11, the assembled battery 10, and the second contactor 12, which are connected in series. In other words, the first contactor 11, the assembled battery 10, and the second contactor 12 are connected in series between the connection points 30, 40.

[0011] Similar to the first system 110, the second system 120 includes a battery pack 20, a first contactor 21, a second contactor 22, a precharge circuit 23, and a service plug 24. The second system 120 is connected in parallel to the first system 110 via connection points 30 and 40. The circuit configuration of the first system 110 in the battery module 100 will be described below. Here, since the first system 110 and the second system 120 have similar circuit configurations, description of the circuit configuration of the second system 120 will be omitted.

[0012] <1st system 110> In the first system 110, the battery pack 10, the first contactor 11, and the second contactor 12 are connected in series. In the first system 110, a precharge circuit 13 is connected in parallel to the second contactor 12. In addition, in the first system 110, a service plug 14 is connected in series to the battery pack 10, the first contactor 11, and the second contactor 12.

[0013] <Battery 10> The battery pack 10 is a battery group in which a predetermined number of unit cells are connected in series via a bus bar. As the unit cells, for example, secondary batteries such as lithium ion secondary batteries and nickel-metal hydride 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 can be used. The battery pack 10 may be connected to one or more unit cells connected in parallel.

[0014] <First Contactor 11> The first contactor 11 is connected in series to the battery pack 10 from the positive electrode side. The first contactor 11 is a device that switches between electrical connection and disconnection between the battery pack 10 and the external load 200 on the positive electrode side of the battery pack 10. The first contactor 11 is configured to be switchable between an open state and a closed state. The open state is a state in which the battery pack 10 and the external load 200 are disconnected on the positive electrode side of the battery pack 10. The closed state is a state in which the battery pack 10 and the external load 200 are connected on the positive electrode side of the battery pack 10. The first contactor 11 is connected to the control device 50 so as to be able to communicate with the control device 50. The first contactor 11 is controlled by the control device 50 to switch between a closed state and an open state.

[0015] <Second Contactor 12> The second contactor 12 is connected in series to the battery pack 10 from the negative electrode side. The second contactor 12 is a device that switches between electrical connection and disconnection between the battery pack 10 and the external load 200 on the negative electrode side of the battery pack 10. The second contactor 12 is configured to be switchable between an open state and a closed state. The second contactor 12 is connected to the control device 50 so as to be able to communicate with the control device 50, similar to the first contactor 11. The second contactor 12 is controlled by the control device 50 to switch between a closed state and an open state. When the battery pack 10 is charged or discharged, both the first contactor 11 and the second contactor 12 are closed. When the battery pack 10 is not charged or discharged, at least one of the first contactor 11 and the second contactor 12 can be opened.

[0016] <Precharge circuit 13> In this embodiment, the precharge circuit 13 is connected in parallel to the second contactor 12 connected to the negative electrode side of the battery pack 10. The precharge circuit 13 is a circuit in which a precharge resistor 13a and a third contactor 13b are connected in series. The precharge circuit 13 is a circuit that prevents an inrush current from flowing to the external load 200 immediately after power is supplied from the battery pack 10 to the external load 200. The third contactor 13b of the precharge circuit 13 is connected to the control device 50 so as to be able to communicate with the control device 50. The third contactor 13b is controlled by the control device 50 to be switched between a closed state and an open state.

[0017] In this embodiment, after the first contactor 11 is closed when the external load 200 is started, the third contactor 13b of the precharge circuit 13 is closed before the second contactor 12 is closed. As a result, the external load 200 is connected to the battery pack 10 via the precharge circuit 13 to which the precharge resistor 13a is connected. At this time, the external load 200 is supplied with power from the battery pack 10 at a lower current than when the first contactor 11 and the second contactor 12 are closed immediately after the external load 200 is started. Thereafter, the second contactor 12 is closed when the potential of the external load 200 is increased. This prevents a large current from flowing to the external load 200.

[0018] <Service Plug 14> The service plug 14 is a device for physically switching between connection and disconnection of the circuit between the battery module 100 and the external load 200. The service plug 14 is appropriately disconnected to interrupt the power circuit during inspection and maintenance of parts through which a large current may flow, such as the battery module 100 and the external load 200. The service plug 14 is connected in series to the battery pack 10 and the external load 200.

[0019] The service plug 14 is provided between a connection point 30 on the positive electrode side of the battery pack 10 and a connection point 40 on the negative electrode side of the battery pack 10. In this embodiment, the service plug 14 is provided on the opposite electrode side of the battery pack 10 to the second contactor 12 to which the precharge circuit 13 is connected in parallel. In other words, the service plug 14 is provided on the positive electrode side of the battery pack 10. The service plug 14 is connected in series to the first contactor 11. In this embodiment, the service plug 14 is provided between the first contactor 11 and the connection point 30.

[0020] The location of the service plug 14 is not particularly limited as long as it is provided on the opposite pole side of the battery pack 10 to the contactor to which the precharge circuit 13 is connected in parallel. For example, the service plug 14 may be provided between the battery pack 10 and the first contactor 11 in the first system 110 described above.

[0021] The first system 110 may be provided with a fuse 15 for preventing an overcurrent from flowing to the battery pack 10 and the external load 200. The fuse 15 may be connected in series with the battery pack 10 at any position between the connection point 30 on the positive electrode side and the connection point 40 on the negative electrode side. The fuse 15 may be provided between any of the cells constituting the battery pack 10. Although not particularly limited, in this embodiment, the fuse 15 is provided between the first contactor 11 and the service plug 14.

[0022] However, high safety is required for battery modules that require high output from the assembled battery, such as battery modules for electric vehicles. To ensure the safety of the battery module, a service plug is provided in the battery module. Conventionally, as disclosed in International Publication WO 2012 / 168963, a service plug is incorporated in a battery assembly in which a plurality of single cells are connected in series. The service plug can be provided, for example, at a position in the assembled battery where the voltage is approximately half.

[0023] In the above-described embodiment, the battery module 100 includes the battery pack 10, the first contactor 11, the second contactor 12, a pair of connection points 30, 40, a precharge circuit 13, and a service plug 14. The first contactor 11 is connected in series to the battery pack 10 from the positive electrode side of the battery pack 10. The second contactor 12 is connected in series to the battery pack 10 from the negative electrode side of the battery pack 10. The pair of connection points 30, 40 are provided at both ends of the first contactor 11, the battery pack 10, and the second contactor 12, which are connected in series, and are connected to an external load 200. The precharge circuit 13 is connected in parallel to the second contactor 12. The precharge circuit 13 includes a precharge resistor 13a and a third contactor 13b, which are connected in series. The service plug 14 is provided between the pair of connection points 30, 40 on the opposite polarity side of the battery pack 10 to the second contactor 12 to which the precharge circuit 13 is connected in parallel. The service plug 14 is connected in series to the first contactor 11.

[0024] In the battery module 100, safety is ensured during work such as inspection and maintenance (hereinafter simply referred to as "work") by disconnecting the service plug 14. In the above-described embodiment, the precharge circuit 13 is provided on the negative electrode side of the battery pack 10, and the service plug 14 is provided on the positive electrode side of the battery pack 10. By providing a configuration for ensuring safety on each of the positive and negative electrode sides of the battery pack 10, safety during work can be improved.

[0025] For example, in the above-described embodiment, the safety during work is improved when a defect occurs in which the first contactor 11 on the positive electrode side of the battery pack 10 is welded. In the case where a service plug is provided between the cells in a battery pack connected in series as in the past, even if the service plug is disconnected, a part of the battery pack is physically connected to an external load on both the positive and negative electrode sides of the battery pack. In the above-described embodiment, even if the first contactor 11 is welded, the connection between the positive electrode side of the battery pack 10 and the external load 200 is physically cut off by disconnecting the service plug 14. Therefore, even if the first contactor 11 is welded, work can be performed more safely.

[0026] In addition, in the battery module 100, in order to ensure safety, welding of the contactors included in the battery module 100 may be judged. Even when it is necessary to judge which of the first contactor 11 and the second contactor 12 is welded, the number of welding judgments for ensuring the safety of the work can be reduced. For example, the connection between the positive electrode side of the battery pack 10 and the external load 200 can be cut by the service plug 14. Therefore, the welding judgment for ensuring the safety of the work is not necessarily required. Regarding the welding judgment for ensuring the safety of the work, the safety of the work can be ensured by judging the presence or absence of welding of the second contactor 12 that switches the connection between the negative electrode side of the battery pack 10 and the external load 200.

[0027] As described above, the battery module 100 includes the first system 110, the second system 120 having the same circuit configuration as the first system 110, and the control device 50. The second system 120 includes the battery pack 20, the first contactor 21 connected in series from the positive electrode side of the battery pack 20, the second contactor 22 connected in series from the negative electrode side of the battery pack 20, the precharge circuit 23, the service plug 24, and the fuse 25. The precharge circuit 23 has a precharge resistor 23a and a third contactor 23b connected in series, and is connected in series to the second contactor 22. The control device 50 is configured to be able to determine which of the contactors included in the battery module 100 is welded. This makes it easier to ensure the safety of the battery module 100. Hereinafter, an example of the process executed by the control device 50 will be described.

[0028] <Control device 50> As described above, the control device 50 controls switching between the closed state and the open state of the first contactor 11, the second contactor 12, and the third contactor 13b. The control device 50 is, for example, a microcomputer. The control device 50 includes, for example, a communication interface, a CPU, a ROM, and a RAM. As shown in FIG. 1, the control device 50 includes an instruction unit 51, an acquisition unit 52, and a determination unit 53. The instruction unit 51, the acquisition unit 52, and the determination unit 53 may be realized by, for example, a plurality of processors. The instruction unit 51, the acquisition unit 52, and the determination unit 53 may be configured to be able to communicate with each other.

[0029] The instruction unit 51 is connected to the contactors 11, 12, 21, 22, 13b, and 23b included in the battery module 100. The instruction unit 51 is configured to be able to instruct each of the contactors 11, 12, 21, 22, 13b, and 23b to switch between a closed state and an open state. The instruction unit 51 is communicably connected to the contactors 11, 12, 21, 22, 13b, and 23b. Here, expressions such as "instruct to close state" and "instruct to open state" mean that the control device 50 issues an instruction to switch or maintain the contactor in the instructed state, such as sending a signal to make the contactor in the closed state or open state. For this reason, for example, when the contactor is welded, the closed state can be maintained even if the open state is instructed.

[0030] The acquisition unit 52 acquires the voltage applied to the external load 200. The acquisition unit 52 is connected to a voltage measurement device 60 so as to be able to communicate with the voltage measurement device 60. The voltage measurement device 60 is connected in parallel to the external load 200 and may be a device capable of measuring the voltage applied to the external load 200. The determination unit 53 determines whether the contactors 11, 12, 21, and 22 included in the battery module 100 are welded based on the voltage value of the external load 200. The control device 50 may be configured to automatically input a system number for determining whether or not the contactors are welded. The number of systems connected in parallel (2 in this embodiment) may be recorded in advance in the control device 50.

[0031] Fig. 2 is a flowchart showing the processing executed by the control device 50. Fig. 2 shows a flowchart for determining whether the first contactors 11, 21 and the third contactors 13b, 23b are welded, which is executed when the external load 200 is started. When the external load 200 is started, the first contactors 11, 21, the second contactors 12, 22, and the third contactors 13b, 23b are all instructed to be open, and the following control is started.

[0032] When the external load 200 is started, a system for which the presence or absence of welding is to be determined is selected. The number of the system for which the presence or absence of welding is to be determined is represented by, for example, n (i.e., the nth system). Immediately after the external load 200 is started, 0 is input to n. In step S0, n+1 is substituted for n. Therefore, 1 is input to n, and the presence or absence of welding of the contactor of the first system 110 is determined.

[0033] In step S2, the instruction unit 51 instructs the third contactor 13b of the first system 110 to be in a closed state. In step S4, the determination unit 53 determines whether or not the voltage value of the external load 200 acquired by the acquisition unit 52 is equal to or lower than a specified value. The specified value here can be determined in advance based on a voltage value that can be taken when the external load 200 is not connected to the assembled batteries 10 and 20. The specified value can be set to a voltage value that is higher than a voltage value that can be taken when the external load 200 is not connected to the assembled batteries 10 and 20 and lower than a voltage value that can be taken when the external load 200 is connected to the assembled batteries 10 and 20. The specified value can be set to a value that is slightly higher than a voltage value that can be taken when the external load 200 is not connected to the assembled batteries 10 and 20, for example.

[0034] If the first contactor 11 of the first system 110 is welded, when the third contactor 13b is closed in step S2, the positive electrode side of the battery pack 10 is connected to the external load 200 via the welded first contactor 11. Therefore, the voltage value of the external load 200 may become higher than the specified value. If the voltage value of the external load 200 is not equal to or lower than the specified value in step S4 (No), the process proceeds to step S30. In step S30, the determination unit 53 determines that the first contactor 11 of the first system 110 is welded. At this time, the start of the external load 200 is stopped, and inspection, maintenance, etc. may be performed.

[0035] If the voltage value of the external load 200 is below the specified value (Yes) in step S4, in step S6, the judgment unit 53 judges that the first contactor 11 of the first system 110 is not welded, and the instruction unit 51 instructs the third contactor 13b of the first system 110 to be in the open state.

[0036] In step S8, it is determined whether n (here, 1) is equal to or greater than the number of systems connected in parallel (in this embodiment, 2). Since n is not equal to or greater than the number of systems connected in parallel (No), the process returns to step S0. Returning to step S0, 2 is input into n.

[0037] In step S2, the instruction unit 51 instructs the third contactor 23b of the second system 120 to be in a closed state. In step S4, the determination unit 53 determines whether or not the voltage value of the external load 200 acquired by the acquisition unit 52 is equal to or less than a specified value. If the voltage value of the external load 200 is not equal to or less than the specified value (No) in step S4, the process proceeds to step S30. In the same manner as in the above-described determination of welding of the first contactor 11 of the first system 110, in step S30, the determination unit 53 determines that the first contactor 21 of the second system 120 is welded. At this time, the start of the external load 200 is stopped, and inspection, maintenance, and the like can be performed.

[0038] If the voltage value of the external load 200 is equal to or lower than the specified value (Yes) in step S4, in step S6, the judgment unit 53 judges that the first contactor 21 of the second system 120 is not welded, and the instruction unit 51 instructs the third contactor 23b of the second system 120 to be in the open state.

[0039] In step S8, it is again determined whether n (here, 2) is the number of systems connected in parallel (in this embodiment, 2). Since n is the number of systems connected in parallel (Yes), the process proceeds to step S10.

[0040] In step S10, the first contactor 11 of the first system 110 and the first contactor 21 of the second system 120 are instructed to be in a closed state. In step S12, the third contactor 13b of the first system 110 is instructed to be in a closed state.

[0041] In step S14, the determination unit 53 determines whether the voltage value of the external load 200 acquired by the acquisition unit 52 is equal to or greater than a specified value. The specified value here can be determined in advance based on a possible voltage value when the external load 200 is connected to the battery pack 10. The specified value can be set to a voltage value lower than a possible voltage value when the external load 200 is connected to the battery pack 10.

[0042] When an abnormality occurs in the precharge circuit 13 of the first system 110 (for example, a failure of the precharge resistor 13a or the third contactor 13b, etc.), a problem may occur in the connection between the external load 200 and the battery pack 10 via the precharge circuit 13. For this reason, the acquired voltage value may be lower than when the external load 200 and the battery pack 10 are normally connected via the precharge circuit 13. If the voltage value acquired in step S14 is not equal to or higher than the specified value (No), the process proceeds to step S40. In step S40, the determination unit 53 determines that an abnormality has occurred in the precharge circuit 13 of the first system 110. At this time, the start of the external load 200 is stopped, and inspection, maintenance, etc. may be performed.

[0043] If the voltage value acquired in step S14 is equal to or greater than the specified value (Yes), in step S16, the determination unit 53 determines that the precharge circuit 13 is normal. The instruction unit 51 instructs the second contactors 12, 22 of the first system 110 and the second system 120 to be in a closed state. In step S18, the instruction unit 51 instructs the third contactor 13b of the first system 110 to be in an open state. The external load 200 is started normally.

[0044] The above-mentioned control at the start of the external load 200 may be performed, for example, after the result of the welding determination performed when the external load 200 is stopped is confirmed. The control at the start of the external load 200 is not limited to the above-mentioned form. For example, in step S12, the third contactor 23b of the second system 120 may be closed, and the presence or absence of an abnormality in the pre-charge circuit 23 may be determined. In step S12, both the third contactor 13b of the first system 110 and the third contactor 23b of the second system 120 may be closed. In addition, the voltage measurement and the presence or absence of an abnormality in the pre-charge circuits 13, 23 may not be performed in step S14.

[0045] In the above-described embodiment, the control device 50 is configured to execute a process (S2) of instructing the third contactor 13b to be in a closed state from a state in which the first contactor 11, the second contactor 12, and the third contactor 13b of the first system 110 are instructed to be in an open state, a process (S4) of determining whether or not the voltage value of the external load 200 is equal to or lower than a predetermined value, and a process (S30) of determining that the first contactor 11 is welded when the voltage value of the external load 200 is not equal to or lower than the predetermined value (S4, No). By detecting the welding of the first contactor 11 through such processes, it is possible to perform inspection, maintenance, etc. to prevent possible malfunctions of the battery module 100, the external load 200, etc. In addition, the control device 50 is configured to be able to execute the same process for the second system 120. By executing the above processes individually for each of the first system 110 and the second system 120, it is possible to determine which system's first contactor is welded. This makes it easier to identify the first contactor that needs to be inspected and maintained. The number of systems is not limited to two as described above, and three or more systems may be connected in parallel.

[0046] Fig. 3 is a flowchart showing the processing executed by the control device 50. Fig. 3 shows a flowchart for determining whether the second contactors 12, 22 are welded, which is executed when the external load 200 is stopped. When the external load 200 is stopped, the first contactors 11, 21 and the second contactors 12, 22 are instructed to be in the closed state, and the third contactors 13b, 23b are instructed to be in the open state, and the following control is started.

[0047] In step S50, the instruction unit 51 instructs the second contactors 12, 22 to be in an open state. In step S52, the determination unit 53 determines whether the voltage of the external load 200 is equal to or lower than a specified value. The specified value here may be the same value as the specified value used to determine whether the first contactors 11, 21 are welded when the external load 200 is started.

[0048] When at least one of the second contactors 12, 22 is welded, even if the first contactors 11, 21 are instructed to be open in step S50, at least one of the assembled batteries 10, 20 will be electrically connected to the external load 200 via the welded contactor. Therefore, the voltage value of the external load 200 may become higher than the specified value.

[0049] In step S52, if the voltage value of the external load 200 is equal to or lower than the specified value (Yes), it is determined that neither of the second contactors 12, 22 is welded, and the process proceeds to step S54. In step S54, the instruction unit 51 instructs the first contactors 11, 21 to be in the open state. The external load 200 is normally stopped.

[0050] In step S52, if the voltage value of external load 200 is not equal to or less than the specified value (No), it is determined that either of second contactors 12, 22 is welded, and the process proceeds to step S60. In step S60 and thereafter, it can be determined which of second contactors 12, 22 is welded.

[0051] In step S60, the instruction unit 51 instructs the first contactor 11 of the first system 110 to be in the open state. The first contactor 21 of the second system 120 remains in the closed state.

[0052] When the second contactor 22 of the second system 120 is not welded, the battery pack 20 of the system 120 and the external load 200 are electrically disconnected. When the first contactor 11 of the first system 110 is welded, the connection between the battery pack 10 of the first system 110 and the external load 200 is cut off by the process of step S60. Therefore, the voltage value of the external load 200 may become lower than the specified value by the process of step S60.

[0053] In step S62, the determination unit 53 determines whether or not the voltage of the external load 200 is equal to or lower than the specified value. If the voltage of the external load 200 is equal to or lower than the specified value (Yes) in step S62, the process proceeds to step S64. In step S64, the determination unit 53 determines that the second contactor 12 of the first system 110 is welded. In step S66, the instruction unit 51 instructs the first contactor 21 of the second system 120 to be in an open state. The external load 200 is stopped, and inspection, maintenance, and the like can be performed.

[0054] In step S62, if the voltage of the external load 200 is not equal to or lower than the specified value (No), the process proceeds to step S70. In step S70, the instructing unit 51 instructs the first contactor 11 of the first system 110 to be in the closed state, and instructs the first contactor 21 of the second system 120 to be in the open state.

[0055] When the second contactor 12 of the first system 110 is not welded, the battery pack 10 of the first system 110 and the external load 200 are electrically disconnected. When the second contactor 22 of the second system 120 is welded, the connection between the battery pack 20 of the second system 120 and the external load 200 is cut off by the process of step S60. Therefore, the voltage value of the external load 200 may become lower than the specified value by the process of step S60.

[0056] In step S72, the determination unit 53 determines whether or not the voltage of the external load 200 is equal to or lower than the specified value. If the voltage of the external load 200 is equal to or lower than the specified value (Yes) in step S72, the process proceeds to step S74. In step S74, the determination unit 53 determines that the second contactor 22 of the second system 120 is welded. In step S76, the instruction unit 51 instructs the first contactor 11 of the first system 110 to be in an open state. The external load 200 is stopped, and inspection, maintenance, and the like can be performed.

[0057] In the above-mentioned step S62, the voltage value of the external load 200 is measured in a state in which the first contactor 11 of the first system 110 is controlled to be in an open state and the first contactor 21 of the second system 120 is controlled to be in a closed state. In the above-mentioned step S72, the voltage value of the external load 200 is measured in a state in which the first contactor 11 of the first system 110 is controlled to be in a closed state and the first contactor 21 of the second system 120 is controlled to be in an open state. If both of the second contactors 12 and 22 are welded, and in any of the processes in step S72, the voltage of the external load 200 may be higher than the specified value. Therefore, in step S72, if the voltage value of the external load 200 is not equal to or lower than the specified value (No), it is determined that both of the second contactors 12 and 22 are welded (step S80). The external load 200 may be stopped and inspected, maintained, or the like.

[0058] In the above-described embodiment, the control device 50 is configured to execute a process (S50) of instructing the second contactors 12, 22 to be in an open state from a state in which the first contactors 11, 21 and the second contactors 12, 22 are instructed to be in a closed state and the third contactors 13b, 23b are instructed to be in an open state, a process (S52) of determining whether or not the voltage value of the external load 200 is equal to or lower than a predetermined value, a process (S60, 70) of instructing the first contactor to be in an open state if the voltage value of the external load 200 is not equal to or lower than the predetermined value (No in S52), a process (S62, S72) of determining whether or not the voltage value of the external load 200 is equal to or lower than a predetermined value after the first contactor is instructed to be in an open state, and a process (S64, 74) of determining that the second contactor is welded if the voltage value of the external load 200 is equal to or lower than the predetermined value (Yes in S62, S72). Here, if the determination in step S62 is Yes, it is determined that the second contactor 12 of the first system 110 is welded. If the determination in step S72 is Yes, it is determined that the second contactor 22 of the second system 120 is welded. In this way, the control device 50 can also determine which second contactor is welded. By executing such processing and detecting the welding of the second contactor, it is possible to perform inspection, maintenance, etc. to prevent possible malfunctions in the battery module 100, the external load 200, etc. It is to be noted that the number of systems is not limited to the above-mentioned two, and three or more systems may be connected in parallel.

[0059] Furthermore, when there is one system (for example, when only the first system 110 is connected to the external load 200), the second contactor 12 of the first system 110 is determined to be welded when the voltage value of the external load 200 is not equal to or lower than a predetermined value in the above-mentioned control. At this time, the processes from step S60 onward for identifying which of the multiple systems has welded contactors need not be executed. Even when there are multiple systems, by executing such control, it can be determined that at least one of the second contactors 12, 22 has welded.

[0060] The above-described control of the determination of welding of the contactor and the determination of abnormality detection of the precharge circuit is merely an example, and the timing and control method are not limited to those described above.

[0061] The circuit configuration of the battery module is not limited to the above-mentioned form. Fig. 4 is a schematic diagram showing a battery module 100A. In the battery module 100A shown in Fig. 4, the precharge circuits 13, 23 are connected in parallel to the first contactors 11, 21, and the service plugs 14, 24 are connected in series to the second contactors 12, 22. In the battery module 100A, the precharge circuits 13, 23 and the service plugs 14, 24 are provided on different poles of the assembled batteries 10, 20, so that the safety during work is improved when a malfunction such as welding of the contactors occurs. In addition, welding of the contactors can be detected by executing a process similar to that described above.

[0062] The technology disclosed herein has been described above 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 each component and each process described herein can be omitted or combined as appropriate, unless a particular problem occurs.

[0063] For example, in the above-described embodiment, the first system 110 and the second system 120 are provided with the fuses 15 and 25, respectively. Without being limited to this embodiment, the battery system 1 may further be provided with a fuse connected in series to the external load 200. For example, when the number of systems increases, the battery system may be provided with a fuse that prevents a large current from flowing to the external load while preventing the fuse from being blown in each system.

[0064] This specification also includes the disclosures described in the following sections.

[0065] Section 1: A battery pack; a first contactor connected in series to the battery pack from a positive electrode side of the battery pack; a second contactor connected in series to the battery pack from a negative electrode side of the battery pack; a pair of connection points provided at both ends of the first contactor, the assembled battery, and the second contactor, the connection points being connected to an external load; a precharge circuit connected in parallel to one of the first contactor and the second contactor, the precharge circuit having a precharge resistor and a third contactor connected in series; Service plug and Equipped with the service plug is provided between the pair of connection points on the opposite pole side of the battery pack to the one of the contactors to which the precharge circuit is connected in parallel, and is connected in series to the other of the first contactor and the second contactor.

[0066] Section 2: the precharge circuit is connected in parallel to the second contactor; Item 2. The battery module according to item 1, wherein the service plug is connected in series to the first contactor.

[0067] Section 3: the precharge circuit is connected in parallel to the first contactor; Item 2. The battery module according to item 1, wherein the service plug is connected in series to the second contactor.

[0068] Section 4: A control device is further provided. The control device includes: a process of instructing the third contactor to a closed state from a state in which the first contactor, the second contactor, and the third contactor are instructed to be in an open state; A process of determining whether a voltage value of the external load is equal to or lower than a predetermined value; determining that the first contactor is welded when a voltage value of the external load is not equal to or less than the predetermined value; The battery module according to any one of items 1 to 3, configured to perform the above.

[0069] Section 5: A control device is further provided. The control device includes: a process of instructing the second contactor to be in an open state from a state in which the first contactor and the second contactor are instructed to be in a closed state and the third contactor is instructed to be in an open state; A process of determining whether a voltage value of the external load is equal to or lower than a predetermined value; determining that the second contactor is welded when the voltage value of the external load is not equal to or less than the predetermined value; The battery module according to any one of items 1 to 3, configured to perform the above.

[0070] Item 6: A control device is further provided. The control device includes: a process of instructing the second contactor to be in an open state from a state in which the first contactor and the second contactor are instructed to be in a closed state and the third contactor is instructed to be in an open state; A process of determining whether a voltage value of the external load is equal to or lower than a predetermined value; a process of instructing the first contactor to be in an open state when a voltage value of the external load is not equal to or less than the predetermined value; a process of determining whether or not a voltage value of the external load is equal to or lower than the predetermined value after the first contactor is instructed to be in an open state; a process of determining that the second contactor is welded when a voltage value of the external load is equal to or lower than the predetermined value; The battery module according to any one of items 1 to 3, configured to perform the above.

[0071] Section 7: A battery pack; a first contactor connected in series to the battery pack from a positive electrode side of the battery pack; a second contactor connected in series to the battery pack from a negative electrode side of the battery pack; a precharge circuit connected in parallel to one of the first contactor and the second contactor, the precharge circuit having a precharge resistor and a third contactor connected in series; a service plug that is provided on an opposite pole side of the battery pack to the one contactor to which the precharge circuit is connected in parallel, and that is connected in series to the other of the first contactor and the second contactor; A battery system comprising: [Explanation of symbols]

[0072] 1 Battery System 10,20 Battery pack 11,21 First Contactor 12,22 Second Contactor 13,23 Precharge circuit 13b, 23b 3rd contactor 13a, 23a Precharge resistor 14,24 Service plug 15,25 Fuse 30,40 Connection point 50 Control device 51 Instruction section 52 Acquisition Department 53 Judgment section 60 Voltage measuring device 100,100A battery module 110 1st system 120 2nd system 200 External Load

Claims

1. A plurality of systems connected in parallel to a pair of connection points connected to an external load; Control device and Equipped with The plurality of lines include A battery pack; a first contactor connected in series to the battery pack from a positive electrode side of the battery pack; a second contactor connected in series to the battery pack from a negative electrode side of the battery pack; a precharge circuit connected in parallel to one of the first contactor and the second contactor, the precharge circuit having a precharge resistor and a third contactor connected in series; The side where the precharge circuit is provided is a service plug connected in series to the other contactor on the opposite side via the battery pack. Each of these features is provided. The control device includes: a process of instructing the third contactor to a closed state from a state in which the first contactor, the second contactor, and the third contactor are instructed to be in an open state; A process of determining whether a voltage value of the external load is equal to or lower than a predetermined value; determining that the first contactor is welded when a voltage value of the external load is not equal to or less than the predetermined value; is executed sequentially for the plurality of systems.

2. The control device further comprises: When the external load is stopped, a process of instructing the second contactor to be in an open state from a state in which the first contactor and the second contactor are instructed to be in a closed state and the third contactor is instructed to be in an open state for the plurality of systems; A process of determining whether or not a voltage value of the external load is equal to or lower than a predetermined value; The battery module according to claim 1 , wherein the following is configured to be performed:

3. The control device includes: When the voltage value of the external load is not equal to or less than the predetermined value, a process of instructing the second contactor to be in an open state from a state in which the first contactor and the second contactor are instructed to be in a closed state and the third contactor is instructed to be in an open state; A process of determining whether a voltage value of the external load is equal to or lower than a predetermined value; a process of instructing the first contactor to be in an open state when a voltage value of the external load is not equal to or less than the predetermined value; a process of determining whether or not a voltage value of the external load is equal to or lower than the predetermined value after the first contactor is instructed to be in an open state; The battery module according to claim 2 , wherein the first and second power supply circuits are configured to be sequentially operated for the plurality of systems.

4. A plurality of systems connected in parallel to a pair of connection points connected to an external load; Control device and Equipped with The plurality of lines include A battery pack; a first contactor connected in series to the battery pack from a positive electrode side of the battery pack; a second contactor connected in series to the battery pack from a negative electrode side of the battery pack; a precharge circuit connected in parallel to one of the first contactor and the second contactor, the precharge circuit having a precharge resistor and a third contactor connected in series; The side where the precharge circuit is provided is a service plug connected in series to the other contactor on the opposite side via the battery pack. Each of these features is provided. The control device includes: When the external load is stopped, a process of instructing the second contactor to be in an open state from a state in which the first contactor and the second contactor are instructed to be in a closed state and the third contactor is instructed to be in an open state for the plurality of systems; A process of determining whether or not a voltage value of the external load is equal to or lower than a predetermined value; The battery module is configured to execute the above.

5. The control device includes: When the voltage value of the external load is not equal to or less than the predetermined value, A process of instructing the first contactor to be in an open state; a process of determining whether or not a voltage value of the external load is equal to or lower than the predetermined value after the first contactor is instructed to be in an open state; The battery module according to claim 4 , wherein the first and second power supply circuits are configured to sequentially supply the first and second power supplies to the first and second power supply circuits.

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