Battery control device, battery control program, and battery control method

Abstract

To provide a technique that can suppress a load on a relay when switching the relay to adjust the potential of a battery circuit.SOLUTION: A battery control device 9 controls a battery circuit 10 including a battery portion in which a plurality of battery packs, each including at least battery modules 21, 31 that are secondary batteries, are connected in parallel, and an input / output portion 13, and at least one of the plurality of battery packs includes resistors 24, 34 connected in series to the battery module, series relays 23, 33 connected in series to the resistor, and parallel relays 22, 32 connected in parallel to the resistor and the series relay. The battery control device includes a relay control portion 15 that controls the on / off of each relay, and an input / output control portion 16 that controls input / output power between the input / output portion and the battery portion, and the input / output control portion controls the input / output portion to input / output power that suppresses the circulating current on the basis of the current direction and magnitude of the circulating current that flows when the relay control portion adjusts the potential between the battery packs by controlling the on / off of each relay.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Battery control device for controlling a battery circuit including a secondary battery module 、 Battery Control Program and battery control method Regarding. [Background technology]

[0002] Patent Document 1 describes a technology for suppressing inrush current that occurs when charging a capacitive load from a servo power supply. In this technology, when charging of the capacitive load begins, the capacitive load is connected to a current path connected to a resistor with a high resistance value, and as charging progresses, the capacitive load is connected to a current path connected to a resistor with a low resistance value, and as charging progresses further, the capacitive load is connected to a current path without a resistor. By switching the current path in this way, the increase in charging time caused by a decrease in charging current is suppressed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-122158 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 gives an example of a relay as a switching element for switching a current path. When a relay is used, if switching is performed while a current is flowing through the relay, a load is placed on the relay, which may shorten the relay's lifespan. In order to ensure the relay's lifespan, it is necessary to increase the relay capacity.

[0005] In view of the above, an object of the present invention is to provide a technique capable of suppressing the load on a relay when switching the relay to adjust the potential of a battery circuit. [Means for solving the problem]

[0006] The present invention provides a battery control device that controls a battery circuit including a battery unit in which multiple battery packs, each including at least a battery module that is a secondary battery, are connected in parallel, and an input / output unit that inputs and outputs power to the battery unit. In this battery control device, at least one of the multiple battery packs is a resistor-equipped battery pack including a resistor connected in series to the battery module, a series relay connected in series with the resistor to switch on and off a wiring connection, and a parallel relay connected in parallel with the resistor and the series relay to switch on and off the wiring connection. The battery control device includes a relay control unit that controls the on / off of the series relay and the parallel relay, and an input / output control unit that controls the input / output power between the input / output unit and the battery unit. When the relay control unit executes a potential adjustment sequence that adjusts the potential between the multiple battery packs by controlling on / off of the series relay and the parallel relay, the input / output control unit controls the input / output unit to input or output power adjusted to suppress the circulating current based on the direction of the circulating current flowing between the multiple battery packs and the magnitude of the circulating current.

[0007] The battery control device controls a battery circuit including a battery unit in which multiple battery packs, each including at least a battery module that is a secondary battery, are connected in parallel, and an input / output unit that inputs and outputs power to the battery unit. At least one of the multiple battery packs is a resistor-equipped battery pack including a resistor connected in series to the battery module, a series relay connected in series to the resistor for switching on and off a wiring connection, and a parallel relay connected in parallel to the resistor and the series relay for switching on and off the wiring connection. The battery control device includes a relay control unit that controls the on / off of the series relay and the parallel relay, and an input / output control unit that controls the input / output power between the input / output unit and the battery unit. When the relay control unit executes a potential adjustment sequence for adjusting the potential between the multiple battery packs by controlling the on / off of the series relay and the parallel relay, the input / output control unit controls the input / output unit to input and output power adjusted to suppress the circulating current based on the circulating current direction, which is the direction of the circulating current flowing between the multiple battery packs, and the magnitude of the circulating current. Because the potential adjustment sequence can be executed by controlling the on / off of the series relay and the parallel relay while the circulating current is suppressed, the load on the relay when switching the relay to adjust the potential of the battery circuit can be reduced. As a result, the life of the relay can be extended, which contributes to reducing replacement costs, and the capacity of the relay can be reduced, which contributes to reducing component costs.

[0008] The present invention also provides a battery control program applicable to a battery control device that controls a battery circuit including a battery unit in which multiple battery packs, each including at least a battery module that is a secondary battery, are connected in parallel, and an input / output unit that inputs and outputs power to the battery unit, wherein at least one of the multiple battery packs is a resistor-equipped battery pack including a resistor connected in series to the battery module, a series relay connected in series with the resistor for switching on and off a wiring connection, and a parallel relay connected in parallel with the resistor and the series relay for switching on and off the wiring connection. The battery control program causes a computer to execute a relay control step of controlling the on / off of the series relay and the parallel relay, and an input / output control step of controlling input / output power between the input / output unit and the battery unit. When a potential adjustment sequence is executed in the relay control step to adjust a potential between the multiple battery packs by controlling on / off of the series relay and the parallel relay, the input / output control step controls the input / output unit to input and output power adjusted to suppress the circulating current, based on the direction of the circulating current that is the current direction of the circulating current flowing between the multiple battery packs and the magnitude of the circulating current.

[0009] According to the battery control program, when the relay control step executes a potential adjustment sequence for adjusting the potential between a plurality of battery packs by controlling the on / off of the series relays and the parallel relays, the input / output control step executes control of the input / output unit so as to input and output power adjusted to suppress the circulating current based on the circulating current direction, which is the current direction of the circulating current flowing between the plurality of battery packs, and the magnitude of the circulating current. Since the potential adjustment sequence can be executed by controlling the on / off of the series relays and the parallel relays while the circulating current is suppressed, the load on the relays can be suppressed when switching the relays to adjust the potential of the battery circuit. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing a battery control device and a battery circuit controlled by the battery control device according to a first embodiment; [Figure 2] 3 is a flowchart of a battery control process executed by the battery control device according to the first embodiment. [Figure 3] 10A and 10B are diagrams illustrating the execution of a potential adjustment sequence in which a circulating current is suppressed. [Figure 4] 10 is a time chart illustrating the execution of a potential adjustment sequence in which a circulating current is suppressed. [Figure 5] 10 is a flowchart for determining whether or not there is a request to suppress circulating current. [Figure 6] FIG. 10 is a diagram showing a battery control device according to a second embodiment and a battery circuit controlled by the battery control device. [Figure 7] 10A and 10B are diagrams illustrating the execution of a potential adjustment sequence according to the second embodiment. [Figure 8] 10A to 10C are diagrams illustrating the execution of a potential adjustment sequence according to the third embodiment. [Figure 9] FIG. 10 is a diagram showing a battery circuit according to a modified example. [Figure 10] FIG. 10 is a diagram showing a battery circuit according to a modified example. [Figure 11] FIG. 10 is a diagram showing a battery circuit according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment) 1 shows a current control system including a battery control device 9 according to a first embodiment and a battery circuit 10 controlled by the battery control device 9. The battery circuit 10 includes a battery section in which a first battery pack 20 and a second battery pack 30 are connected in parallel, and an input / output section 13 that inputs and outputs power to and from the battery section. The battery control device 9 includes a relay control section 15 and an input / output control section 16.

[0012] The first battery pack 20 and the second battery pack 30 according to this embodiment have the same configuration and are designed to exhibit similar performance. Similar performance, for example, refers to the same batteries and the same degree of deterioration. The same voltage, for example, refers to the same rated voltage, initial full-charge capacity, and internal resistance. The same degree of deterioration, for example, refers to the same current full-charge capacity and internal resistance. The first battery pack 20 includes a first battery module 21 in which multiple secondary batteries (e.g., lithium-ion batteries) are connected in series, a first parallel relay 22, a first series relay 23, and a first resistor 24 connected to the high-potential side of the first battery module 21, and a first current sensor 25 connected to the low-potential side of the first battery module 21. The first parallel relay 22, the first series relay 23, and the first resistor 24 may be connected to the low-potential side of the first battery module 21. The first series relay 23 is connected in series to the first resistor 24 to switch the wiring connection on and off. The first parallel relay 22 is connected in parallel to the first resistor 24 and the first series relay 23 to switch the wiring connection on and off. The first current sensor 25 can be used as a means for detecting the current of the first battery module 21 or the current of the first battery pack 20. The current control system also includes a voltage sensor 17. The voltage sensor 17 detects the voltage of the first battery module 21 and the voltage of the second battery module 31. The voltage sensor 17 may be provided individually for each battery pack 20, 30.

[0013] The second battery pack 30 includes a second battery module 31 in which multiple secondary batteries are connected in series, a second parallel relay 32, a second series relay 33, and a second resistor 34 connected to the high-potential side of the second battery module 31, and a second current sensor 35 connected to the low-potential side of the second battery module 31. The second parallel relay 32, the second series relay 33, and the second resistor 34 may also be connected to the low-potential side of the second battery module 31. The second series relay 33 is connected in series to the second resistor 34 and switches the wiring connection on and off. The second parallel relay 32 is connected in parallel to the second resistor 34 and the second series relay 33 and switches the wiring connection on and off. The second current sensor 35 can be used as a means for detecting the current of the second battery module 31 or the current of the second battery pack 30.

[0014] The first battery pack 20 and the second battery pack 30 are resistor-equipped battery packs that include a resistor connected in series to the battery module, a series relay connected in series to the resistor to switch the wiring connection on and off, and a parallel relay connected in parallel to the resistor and the series relay to switch the wiring connection on and off.

[0015] The first battery pack 20 and the second battery pack 30 are connected to each other on their high potential sides by a high potential side relay 11, and are connected to each other on their low potential sides by a low potential side relay 12. A circuit current sensor 14 is provided on the wiring connecting the low potential sides of the first battery pack 20 and the second battery pack 30 to the input / output unit 13. The circuit current sensor 14 may also be provided on the wiring connecting the high potential sides of the first battery pack 20 and the second battery pack 30 to the input / output unit 13. The first battery pack 20, the second battery pack 30, the high potential side relay 11, the low potential side relay 12, and the circuit current sensor 14 form a battery unit in which a plurality of battery packs, each including at least a battery module that is a secondary battery, are connected in parallel.

[0016] The input / output unit 13 is connected in parallel to the battery unit and inputs and outputs power to the battery unit. The input / output unit in the present application may be a device capable of both inputting power from the battery unit and outputting power to the battery unit, such as a charging / discharging device, or may be a device capable of only inputting power from the battery unit, or may be a device capable of only outputting power to the battery unit. In the first embodiment, a case will be described in which the input / output unit 13 is a charging / discharging device. For example, the battery unit may be mounted on a vehicle and connected to a charging / discharging device external to the vehicle to form the battery circuit 10. The battery control device 9 may be mounted on the vehicle, or may be a device external to the vehicle that is connected to the vehicle for use.

[0017] The battery control device 9 is primarily composed of a well-known microcomputer (MCU) including a CPU, ROM, RAM, flash memory, etc. For example, the CPU executes a program installed in the ROM to realize functions such as the relay control unit 15 and the input / output control unit 16 of the battery control device 9. The functions provided by the MCU may be provided by software stored in a physical memory device and a computer that executes the software, by software alone, by hardware alone, or a combination thereof. For example, when the MCU is implemented by a hardware electronic circuit, the function may be implemented by a digital circuit including multiple logic circuits or an analog circuit. For example, the MCU executes a program stored on a non-transitory physical recording medium that serves as its own storage unit. The program may include, for example, a battery control processing program described below. Execution of the program results in the execution of a method corresponding to the program. The storage unit may be, for example, a non-volatile memory. Note that the program stored in the storage unit can be updated, for example, via a network such as the Internet.

[0018] The relay control unit 15 turns on and off the high potential side relay 11, the low potential side relay 12, the first parallel relay 22, the first series relay 23, the second parallel relay 32, and the second series relay 33. The relay control unit 15 acquires detection data from the first current sensor 25 and the second current sensor 35. The input / output control unit 16 controls the input / output unit 13 to control the input / output power between the input / output unit 13 and the battery unit. The input / output control unit 16 acquires detection data from the circuit current sensor 14. Note that the input / output control unit 16 may be configured to acquire the sum of the detection data from the first current sensor 25 and the second current sensor 35 instead of the detection data from the circuit current sensor 14.

[0019] The relay control unit 15 executes a potential adjustment sequence that adjusts the potential between the first and second battery packs 20, 30 by controlling the on / off of the first parallel relay 22, the first series relay 23, the second parallel relay 32, and the second series relay 33. The potential adjustment sequence is a sequence for preventing relay failures. The following describes an example in which the first and second battery modules 21, 31 are charged by the input / output unit 13 functioning as a charging device. The following describes a case in which the first and second battery modules 21, 31 are charged while the first parallel relay 22 and the second parallel relay 32 are in the on state and the first series relay 23 and the second series relay 33 are in the off state. Depending on the degree of battery module deterioration, charging may end with a difference in potential between the first battery module 21 and the second battery module 31. If the charging current from the input / output unit 13 is interrupted while the potentials are misaligned, an inrush current and a circulating current may flow from the battery module with the higher potential to the battery module with the lower potential of the first and second battery modules 21, 31. In order to suppress this circulating current, a potential adjustment sequence is executed.

[0020] When the relay control unit 15 executes the potential adjustment sequence, the input / output control unit 16 controls the input / output unit 13 to input and output power adjusted to suppress the circulating current based on the circulating current direction, which is the direction of the circulating current flowing between the first and second battery packs 20, 30, and the magnitude of the circulating current. In this embodiment, the current direction is either a first direction in which the current flows from the positive electrode terminal of the first battery module 21 to the positive electrode terminal of the second battery module 31, or a second direction in which the current flows from the positive electrode terminal of the second battery module 31 to the positive electrode terminal of the first battery module 21. The first direction, in other words, is the direction in which the circulating current discharges the first battery module 21 and charges the second battery module 31. The second direction, in other words, is the direction in which the circulating current discharges the second battery module 31 and charges the second battery module 21. For example, the input / output control unit 16 calculates a command value for a circulating canceling current (hereinafter, the current command value Ich*) that flows in the opposite direction to the circulating current and cancels out the circulating current based on the magnitude of the circulating current, and controls the input / output power of the input / output unit 13 based on the calculated current command value Ich*. This control causes the circulating current to be canceled out by the circulating canceling current, reducing the current flowing through the battery pack and approaching zero. With the circulating current suppressed by the input / output control unit 16, the relay control unit 15 can perform on / off control of the first parallel relay 22, the first series relay 23, the second parallel relay 32, and the second series relay 33. This reduces the load on the first parallel relay 22, the first series relay 23, the second parallel relay 32, and the second series relay 33. As a result, the life of each relay can be extended, contributing to reduced replacement costs. Furthermore, the capacity of each relay can be reduced, contributing to reduced component costs.

[0021] The input / output control unit 16 estimates the magnitude and direction of the circulating current based on the voltage of the first battery module 21 (hereinafter referred to as the first voltage V1) and the voltage of the second battery module 31 (hereinafter referred to as the second voltage V2) detected by the voltage sensor 17. For example, the input / output control unit 16 may estimate the magnitude and direction of the circulating current based on the difference between the first voltage V1 and the second voltage V2 and the resistance of the first and second battery packs 20, 30 (specifically, for example, the first and second battery modules 21, 31). Here, the input / output control unit 16 may estimate the resistance of the first and second battery packs 20, 30 based on, for example, map information correlating the temperatures of the first and second battery packs 20, 30 with the resistance of the first and second battery packs 20, 30, or based on the detected values ​​of the first and second current sensors 25, 35 and the first and second voltages V1, V2. Furthermore, the input / output control unit 16 may estimate that the magnitude of the circulating current is greater as the difference between the first voltage V1 and the second voltage V2 increases. Furthermore, the input / output control unit 16 may estimate that the circulating current flows from the positive electrode terminal of the first battery module 21 to the positive electrode terminal of the second battery module 31 when the first voltage V1 is greater than the second voltage V2, and may estimate that the circulating current flows from the positive electrode terminal of the second battery module 31 to the positive electrode terminal of the first battery module 21 when the second voltage V2 is greater than the first voltage V1.

[0022] Fig. 2 shows a flowchart of the battery control process executed by the battery control device 9. The process shown in Fig. 2 is executed by the battery control device 9 when the CPU included in the battery control device 9 executes a battery control program installed in the ROM.

[0023] In step S101, it is determined whether or not there is a request to suppress the circulating current Icr flowing between the battery packs 20 and 30. If there is a request, the process proceeds to step S102.

[0024] Each process shown in steps S102 to S106 is a step for controlling the input / output power between the input / output unit 13 and the battery unit, and corresponds to an input / output control step in which control is performed on the input / output unit 13 so as to input and output power adjusted to suppress the circulating current based on the circulating current direction, which is the current direction of the circulating current flowing between multiple battery packs, and the magnitude of the circulating current.

[0025] More specifically, in step S102, the current command value Ich*, which is a command value for the input / output current to suppress the circulating current, is calculated. In step S103, the input / output power of the input / output unit 13 is controlled based on the calculated current command value Ich*.

[0026] In step S104, it is determined whether the absolute value of the first current value I1 detected by the first current sensor 25 is less than or equal to the absolute value of the second current value I2 detected by the second current sensor 35. If it is determined that |I1|≦|I2|, the process proceeds to step S105, where it is determined whether the absolute value of the first current value I1 is less than or equal to a predetermined first current threshold X1. The first current threshold X1 is a switching current threshold, and is set to a current value that can ensure the desired lifespan of each relay 22, 23 in the first battery pack 20. The relationship between the current flowing through the relay and its lifespan can be derived by experiment, etc. If |I1|≦X1, the process proceeds to step S107. If |I1|>X1, the process proceeds to step S103.

[0027] On the other hand, if it is determined in step S104 that |I1|>|I2|, the process proceeds to step S106, where it is determined whether the absolute value of the second current value I2 is equal to or less than a predetermined second current threshold X2. The second current threshold X2 is a switching current threshold, and is set to a current value that can ensure the desired lifespan of each of the relays 32, 33 in the second battery pack 30. If |I2|≦X2, the process proceeds to step S110. If |I2|>X2, the process proceeds to step S103.

[0028] In step S107, the first series relay (first S relay) 23 is turned on, and then the process proceeds to step S108. In step S108, the first parallel relay (first P relay) 22 is turned off, and then the process proceeds to step S109.

[0029] On the other hand, in step S110, the second series relay (second S relay) 33 is turned on, and then the process proceeds to step S111. In step S111, the second parallel relay (second P relay) 32 is turned off, and then the process proceeds to step S109.

[0030] The processes shown in steps S107, S108, S110, and S111 correspond to a potential adjustment sequence that adjusts the potential between the first and second battery packs 20, 30 by controlling the on / off of the first parallel relay 22 and the first series relay 23, or the on / off of the second parallel relay 32 and the second series relay 33. The processes shown in steps S107, S108, S110, and S111 correspond to a relay control step that controls the on / off of the series relays and parallel relays and executes a potential adjustment sequence that adjusts the potential between the multiple battery packs by controlling the on / off of the series relays and parallel relays.

[0031] In step S109, an input / output current stop command is sent from the input / output control unit 16 to the input / output unit 13. As a result, as shown in step S112, the input / output current flowing between the battery circuit 10 and the input / output unit 13 is stopped. When the input / output current is stopped after the switching control of each relay related to the potential adjustment sequence is completed, the potential between each battery pack 20, 30 is adjusted by the circulating current Icr. More specifically, the potential difference between each battery pack 20, 30 is reduced.

[0032] In step S113, it is determined whether or not there is a load request for the battery unit. If it is determined in step S113 that there is no load request, the process proceeds to step S114.

[0033] In step S114, it is determined whether the magnitude of the circulating current Icr has decreased to a level at which the potential difference adjustment sequence does not need to be performed. For example, if it is determined that the difference between the first voltage V1 and the second voltage V2 is less than a predetermined voltage threshold, it may be determined that the magnitude of the circulating current Icr has decreased (YES).

[0034] If a negative determination is made in step S114, the process proceeds to step S113. On the other hand, if a positive determination is made in step S114, the process proceeds to step S115. If step S107 is performed, the first series relay 23 is turned off in step S115. On the other hand, if step S110 is performed, the second series relay 33 is turned off in step S115.

[0035] If it is determined in step S113 that there is a load request, the process proceeds to step S116. If step S108 has been executed, the first parallel relay 22 is turned on in step S116. On the other hand, if step S111 has been executed, the second parallel relay 32 is turned on in step S116.

[0036] After that, the process proceeds to step S117. If step S107 has been executed, the first series relay 23 is turned off in step S117. On the other hand, if step S110 has been executed, the second series relay 33 is turned off in step S117.

[0037] If it is determined in step S101 that there is no suppression request, the process proceeds to steps S118 and S119. In steps S118 and S119, the same processing as in steps S109 and S112 is performed.

[0038] In step S120, the same process as in step S113 is performed. If it is determined in step S120 that there is no load request, the process proceeds to step S121, where the first and second parallel relays 22, 32 that are in the on state are turned off.

[0039] As described above, according to the battery control process of the first embodiment, when there is a request to suppress the circulating current Icr, a current command value Ich* corresponding to a command value for the circulating cancellation current value is calculated as shown in step S101. The circulating current Icr is appropriately suppressed by adjusting the input / output current through the input / output control step. As a result, the relay control steps shown in steps S107, S108, S110, and S111 are executed, and the potential adjustment sequence is executed, provided that the current (first current value I1, second current value I2) flowing through the wiring in each battery pack 20, 30 is equal to or less than the switching current thresholds (first current threshold X1, second current threshold X2). As a result, the life of the relays in each battery pack 20, 30 can be secured.

[0040] The potential adjustment sequence for suppressing circulating current, which is executed by the above-described battery control process, will be described using Figure 3. Each diagram in Figure 3 is a schematic representation of the battery circuit 10 shown in Figure 1. Figure 3(a) shows a state in which the first battery module 21 and the second battery module 31 are being charged. The first parallel relay 22 and the second parallel relay 32 are in the on state, and a charging current Ich flows from the input / output unit 13 to the battery unit.

[0041] When charging of the first battery module 21 and the second battery module 31 is completed, a request to suppress the circulating current occurs. In this case, the input / output control step controls the charging current Ich from the input / output unit 13 to gradually approach the current command value Ich*, which corresponds to the command value of the circulating canceling current value. As the charging current Ich gradually approaches the current command value Ich*, the first current value I1 and the second current value I2 also gradually decrease.

[0042] Then, when |I1|≦X1 is satisfied, the first series relay 23 is switched to the ON state, as shown in FIG. 3(b). Subsequently, the first parallel relay 22 is switched to the OFF state, as shown in FIG. 3(c). Thereafter, as shown in FIG. 3(d), when the input / output current of the input / output unit 13 is stopped, a circulating current Icr flows in the closed circuit formed by the first battery module 21, first resistor 24, first series relay 23, second parallel relay 32, and second battery module 31, reducing the potential difference between the first battery pack 20 and the second battery pack 30. At this time, the inclusion of the first resistor 24 in the closed circuit can enhance the effect of reducing the circulating current.

[0043] FIG. 4 shows a time chart of the potential adjustment sequence for suppressing circulating current, which is executed by the battery control process described above. The vertical axes of FIGS. 4(a) to 4(g) respectively represent the charging current Ich, the first current value I1, the second current value I2, the current value I1P of the current flowing through the first parallel relay 22, the current value I1S of the current flowing through the first series relay 23, the current value I2P of the current flowing through the second parallel relay 32, and the current value I2S of the current flowing through the second series relay 33, while the horizontal axis represents time t. FIGS. 4(d) to 4(g) also show the on / off states of each relay. In FIG. 4, the first current value I1 is positive when flowing from the positive terminal to the negative terminal of the first battery module 21, and the second current value I2 is positive when flowing from the positive terminal to the negative terminal of the second battery module 31. The charging current Ich is positive when output from the input / output unit 13, and the current values ​​I1P, I1S, I2P, and I2S flowing through each relay are positive when flowing from the high potential side to the low potential side.

[0044] The time chart in Fig. 4 corresponds to the states in Fig. 3(a) to (d). Time t = t0 to t1 in Fig. 4 corresponds to the state in Fig. 3(a). From time t = t0 to t1, as the charging current Ich gradually decreases, the first current value I1, the second current value I2, the current value I1P, and the current value I2P also gradually decrease. Because the first series relay 23 and the second series relay 33 are in the OFF state, the current value I1S and the current value I2S remain constant at zero.

[0045] The period t=t1 to t2 in FIG. 4 corresponds to the states in FIGS. 3(b) and 3(c). From t=t1 to t2, the charging current Ich is maintained at a current value suitable as a circulating canceling current. Because the circulating canceling current is balanced with the circulating current Icr flowing through the first parallel relay 22, the first current value I1 is maintained constant at approximately zero during this period. The second current value I2 and the current value I1S are constant but not approximately zero. Because the second series relay 33 is in the off state, the current value I2S remains constant at approximately zero. During this period, the first series relay 23 is switched to the on state, and then the first parallel relay 22 is switched to the off state. The input / output current at the input / output unit 13 is controlled by the current command value Ich* corresponding to the circulating canceling current, thereby canceling the circulating current. This reduces the current flowing through each battery pack 20, 30 without shutting off the battery circuit 10. Furthermore, since each relay can be switched while the current flowing through each battery pack 20, 30 is reduced, the life of the relay can be secured.

[0046] The state after time t=t2 in FIG. 4 corresponds to the state shown in FIG. 3(d). When a command to stop the input / output current is sent to the input / output unit 13 at time t=t2, the charging current Ich drops to zero in an approximately stepwise manner. Thereafter, the first current value I1 and the second current value I2 gradually converge to zero. Because the first series relay 23 and the second parallel relay 32 are in the ON state, the current values ​​I1S and I2P also gradually converge to zero after time t=t2. As shown in FIG. 3(d), relay control is performed so that the first series relay 23 is in the ON state and the first parallel relay 22 is in the OFF state. This stops the input / output current after the first resistor 24 is included in the current path, thereby suppressing the large current flow during shutdown (time t=t2). Because the first parallel relay 22 and the second series relay 33 are in the OFF state, the current values ​​I1P and I2S remain constant at zero.

[0047] As described above, in the potential adjustment sequence, when the current flowing through at least one resistor-equipped battery pack falls below a predetermined switching current threshold, the relay control unit 15 switches the series relay to the ON state and then switches the parallel relay to the OFF state. This allows each relay to be switched while suppressing the load on each relay, thereby ensuring the relay's lifespan. Even if the battery packs 20 and 30 have the same configuration, the potentials of the battery modules 21 and 31 may differ due to, for example, differences in the degree of deterioration of the battery modules 21 and 31. If input / output power is stopped in this state, there is a concern that a large inrush current or circulating current may flow from the battery pack with a higher potential to the battery pack with a lower potential. According to this embodiment, the circulating current Icr is suppressed by the input / output current controlled to a current command value* equivalent to the circulating cancellation current value, and each relay can be switched while suppressing the load on each relay.

[0048] Furthermore, when the input / output control unit 16 controls the input / output unit 13 so that a charging current flows to the battery unit, the relay control unit 15 switches the current path by controlling the series relays and parallel relays included in the resistor-equipped battery pack in which the circulating current Icr is discharged. In the example shown in Fig. 3, the resistor-equipped battery pack in which the circulating current Icr is discharged is the first battery pack 20 including the first battery module 21. By controlling the charging current from the input / output control unit 16 to the battery unit to the current command value Ich* equivalent to the circulating cancellation current value, it is possible to switch each relay while suppressing the circulating current Icr, thereby suppressing the load on each relay and ensuring the life of the relay.

[0049] 3 and 4, the case where the input / output control unit 16 controls the input / output unit 13 so that a charging current flows to the battery unit has been described. The same applies to the case where the input / output unit 13 is controlled so that a discharging current flows from the battery unit to the input / output control unit 16. When the relay control unit 15 controls the input / output unit 13 so that a discharging current flows from the battery unit to the input / output control unit 16, the relay control unit 15 switches the current path by controlling the series relays and parallel relays included in the resistor-equipped battery pack in which the circulating current Icr is the charging direction. By controlling the discharging current from the battery unit to the input / output control unit 16 to the current command value Ich* corresponding to the circulating cancellation current value, each relay can be switched while suppressing the circulating current Icr. This reduces the load on each relay and ensures the relay's life.

[0050] 2 to 4, after the relay control unit 15 switches the series relay to the ON state, the parallel relay is switched to the OFF state, and then the input / output control unit 16 controls the input / output unit 13 to stop the input / output of power adjusted to suppress the circulating current Icr. Since the input / output current is stopped after the current path is set to include resistance, it is possible to suppress a large current that flows when the input / output current is stopped.

[0051] The input / output control unit 16 may be configured to estimate the current direction and magnitude of the circulating current Icr based on the voltage of each battery module 21, 31 or the voltage of each battery pack 20, 30 and the internal resistance of each battery module 21, 31. Furthermore, the input / output control unit 16 may be configured to control the input / output unit 13 to input or output power adjusted to suppress the circulating current Icr when the circulating current Icr exceeds the upper limit Ib_max of the chargeable / dischargeable current of each battery module 21, 31. This can reduce the current flowing as the circulating current Icr, thereby shortening the potential adjustment time.

[0052] Fig. 5 is a diagram showing a specific example of the process of step S101 shown in Fig. 2. In step S201 shown in Fig. 5, the current direction and magnitude of the circulating current Icr are estimated, and the process proceeds to step S202.

[0053] In step S202, based on the estimation result of step S201, it is determined whether the magnitude of the circulating current Icr exceeds the upper limit (Ib_max) of the chargeable / dischargeable current of the first and second battery modules 21, 31. If Icr>Ib_max, the process proceeds to step S203, where it is determined that there is a request to suppress the circulating current Icr. If Icr≦Ib_max, the process proceeds to step S204, where it is determined that there is no request to suppress the circulating current Icr.

[0054] Furthermore, the resistance value of the resistors included in each resistor-equipped battery pack may be adjustable based on a predetermined battery parameter that affects the circulating current Icr. This can effectively reduce the current flowing as the circulating current Icr, thereby shortening the time required for potential adjustment. One way to adjust the resistance value is to adjust the number of resistors, but other means for adjusting the resistance value can also be used.

[0055] Examples of predetermined battery parameters that affect the circulating current Icr include the voltage, temperature, state of health (SOH), and internal resistance of each battery module 21, 31, but other parameters may also be used. Specifically, when the voltage of each battery module 21, 31 is used as a parameter, the circulating current Icr increases when the voltage difference between the battery modules 21, 31 is high, so the number of resistors is increased to increase their resistance values. For example, the input / output control unit 16 increases the number of resistors by switching the relays 22, 23, 32, and 33 on and off so that both the first and second resistors 24 and 34 are included in the current path. When the temperature is used as a parameter, the circulating current Icr increases when the temperature is high, so the number of resistors is increased to increase their resistance values. When the degree of deterioration is used as a parameter, the circulating current Icr increases when the degree of deterioration is high, so the number of resistors is increased to increase their resistance values. When the internal resistance is used as a parameter, the circulating current Icr decreases when the internal resistance is high, so the number of resistors is reduced to decrease their resistance values. By adjusting the resistance value in this way, it is possible to effectively suppress inrush current and circulating current. Note that the temperature and deterioration level of each battery module 21, 31 are related to the internal resistance, and a high temperature and a high deterioration level correspond to a low internal resistance.

[0056] When there is a load request from the battery module, the relay control unit 15 selects the first mode, switches the parallel relay to the ON state, and then switches the series relay to the OFF state, thereby terminating the potential adjustment sequence. This allows the parallel relay, which does not include a resistor in the current path, to discharge from the battery module in response to the load request. Furthermore, when there is no load request from the battery module, the relay control unit 15 switches the series relay to the OFF state, thereby terminating the potential adjustment sequence, thereby avoiding unnecessary execution of the process of switching the parallel relay to the ON state.

[0057] Furthermore, when a load request is made from the battery unit while the series relay is in the ON state, the input / output control unit 16 controls the input / output unit 13 to input or output power adjusted to suppress the circulating current Icr, and the relay control unit 15 may be configured to turn the series relay to the OFF state and then turn the parallel relay to the ON state. Since the switching of each relay can be performed with the circulating current Icr suppressed, the load on each relay can be suppressed and the life of the relay can be secured.

[0058] The relay control unit 15 may be configured to estimate a circulating current Icr when the parallel relay is switched to the ON state while the series relay is in the ON state, and to switch the parallel relay to the ON state when the estimated value of the circulating current Icr is equal to or less than the upper limit Ib_max of the chargeable / dischargeable current of the battery module. This reduces the current value flowing as the circulating current and shortens the time required for potential adjustment.

[0059] (Second embodiment) In the first embodiment, a case where two battery packs are connected in parallel to form a battery unit has been described as an example, but this is not limiting. Three or more battery packs may be connected in parallel to form a battery unit. In the second embodiment, a case where three battery packs are connected in parallel as shown in FIG. 6 will be described as an example.

[0060] The battery circuit shown in FIG. 6 differs from the battery circuit 10 shown in FIG. 1 in that a third battery pack 40 is provided between the second battery pack 30 and the input / output unit 13. The third battery pack 40 includes a third battery module 41 in which multiple secondary batteries are connected in series, a third parallel relay 42, a third series relay 43, and a third resistor 44 connected to the high-potential side of the third battery module 41. Similarly to the other battery packs 20 and 30, the third battery module 41 also includes a third current sensor 45 connected to the low-potential side of the third battery module 41. The third current sensor 45 can be used to detect the current of the third battery module 41 or the third battery pack 40. The detected value of the third current sensor 45 (hereinafter, the third current value I3) is input to the relay control unit 15. The voltage sensor 17 detects the voltage of the third battery module 41. Note that the battery voltage detected by the voltage sensor 17 is not limited to the terminal voltage of the battery module, but may also be the voltage of the battery cells constituting the battery module.

[0061] 6 does not show the high potential side relay 11, the low potential side relay 12, and the high potential side relay and the low potential side relay provided between the second battery pack 30 and the third battery pack 40. The third parallel relay 42, the third series relay 43, and the third resistor 44 may be connected to the low potential side of the third battery module 41.

[0062] 7(a) to 7(c) are diagrams that schematically show a battery circuit. Note that Fig. 7 will be described taking as an example a case where the input / output unit 13 can function as a charging device.

[0063] As shown in FIG. 7(a), the first parallel relay 22, the second parallel relay 32, and the third parallel relay 42 are in the ON state, and a charging current Ich flows from the input / output unit 13 to the battery unit.

[0064] In the following, the direction of the circulating current flowing through the first and second battery modules 21, 31 is the direction of discharging from the first and second battery modules 21, 31, and the direction of the circulating current flowing through the third battery module 41 is the direction of charging the third battery module 41.

[0065] The input / output control unit 16 identifies the battery modules in which the circulating current flows in the discharging direction based on the first voltage V1, the second voltage V2, and the voltage of the third battery module 41 (hereinafter referred to as the third voltage V3) detected by the voltage sensor 17. In the example shown in Fig. 7, the input / output control unit 16 identifies the first and second battery modules 21 and 31 as the battery modules in which the circulating current flows in the discharging direction.

[0066] The input / output control unit 16 identifies the battery module with the smallest circulating current among the first and second battery modules 21, 31 in the discharging direction based on the first to third voltages V1 to V3. The input / output control unit 16 may identify the battery pack with the smallest circulating current based on the first to third voltages V1 to V3, for example. In the example shown in Fig. 7, the input / output control unit 16 identifies the first battery module 21 as the battery pack with the smallest circulating current.

[0067] The input / output control unit 16 controls the output power of the input / output unit 13 so that the absolute value of the first current value I1 flowing through the first battery pack 20, at which the magnitude of the circulating current is minimum, is equal to or less than the switching current threshold (first current threshold X1). Specifically, for example, the input / output control unit 16 calculates the current command value Ich* and controls the output power of the input / output unit 13 so that the charging current supplied from the input / output unit 13 to the first battery module 21 is the same in magnitude as the circulating current flowing through the first battery module 21. This makes it possible to suppress the circulating current while minimizing the charging current output from the input / output unit 13.

[0068] After that, in a state where |I1|≦X1 is satisfied, the relay control unit 15 switches the first series relay 23 to the ON state as shown in Fig. 7(b), and then switches the first parallel relay 22 to the OFF state as shown in Fig. 7(c). Although not shown, the input / output current of the input / output unit 13 may then be stopped, as in Fig. 3(d).

[0069] In the second embodiment, the battery unit includes first to third battery packs 20, 30, and 40, which are three resistor-equipped battery packs connected in parallel to one another. In this case, the input / output control unit 16 controls the input / output power of the input / output unit 13 so that the current flowing through, for example, the first battery pack 20, which has the smallest circulating current Icr among the first to third battery packs 20, 30, and 40, is equal to or less than the switching current threshold (first current threshold X1). It is possible to execute the potential adjustment sequence by minimizing the input / output power of the input / output unit 13.

[0070] Furthermore, the input / output control unit 16 may be configured to determine whether the current from the input / output unit 13 to the battery unit is a charging current or a discharging current depending on the direction of the current flowing through the series relay or parallel relay included in the resistor-equipped battery pack in which the magnitude of the circulating current Icr is minimum.

[0071] Instead of functioning as a charging device, the input / output unit 13 may function as a discharging device, or the input / output unit 13 may function as a charging / discharging device. First, a case where the input / output unit 13 can function as a discharging device (for example, a DC-DC converter) will be described. The discharging device has a function of receiving power from the battery module side.

[0072] The input / output control unit 16 identifies the battery modules in which the circulating current direction is the charging direction based on the first to third voltages V1 to V3. In the example described below, the input / output control unit 16 identifies the first and second battery modules 21 and 31 as the battery modules in which the circulating current direction is the charging direction.

[0073] The input / output control unit 16 identifies the battery module with the smallest circulating current magnitude among the first and second battery modules 21, 31 in the charging direction based on the first to third voltages V1 to V3. In the example described below, the input / output control unit 16 identifies the first battery module 21 as the one with the smallest circulating current magnitude.

[0074] The input / output control unit 16 controls the input power of the input / output unit 13 so that the absolute value of the first current value I1 flowing through the first battery pack 20, at which the magnitude of the circulating current is minimum, is equal to or less than a switching current threshold (first current threshold X1). Specifically, for example, the input / output control unit 16 calculates the current command value Ich* and controls the input power of the input / output unit 13 so that the discharge current flowing from the first battery module 21 to the input / output unit 13 is equal to the magnitude of the circulating current flowing through the first battery module 21. Thereafter, in a state where |I1|≦X1 is satisfied, the relay control unit 15 switches the first series relay 23 to the ON state, and subsequently switches the first parallel relay 22 to the OFF state.

[0075] Next, a case where the input / output unit 13 can function as either a discharge device or a charge device will be described.

[0076] The input / output control unit 16 identifies the battery module with the smallest circulating current among the first, second, and third battery modules 21, 31, and 41 based on the first to third voltages V1 to V3. In the example described below, the input / output control unit 16 identifies the first battery module 21 as having the smallest circulating current. The input / output control unit 16 determines whether the direction of the circulating current flowing through the first battery module 21 is the charging direction or the discharging direction of the first battery module 21.

[0077] When the input / output control unit 16 determines that the direction of the circulating current flowing through the first battery module 21 is the discharging direction, it calculates the current command value Ich* and controls the output power of the input / output unit 13 so that the charging current supplied from the input / output unit 13 to the first battery module 21 is the same in magnitude as the circulating current flowing through the first battery module 21.

[0078] On the other hand, when the input / output control unit 16 determines that the direction of the circulating current flowing through the first battery module 21 is the charging direction, it calculates the current command value Ich* and controls the input power of the input / output unit 13 so that the discharge current flowing from the first battery module 21 to the input / output unit 13 is the same in magnitude as the circulating current flowing through the first battery module 21.

[0079] (Third embodiment) In each of the above embodiments, the relay switching related to the potential adjustment sequence is performed in only one battery pack among the multiple resistor-equipped battery packs that make up the battery unit, but this is not limiting, and the potential adjustment sequence may be performed in multiple battery packs.

[0080] Each diagram in FIG. 8, like FIG. 3, is a schematic representation of the battery circuit 10 shown in FIG. 1. Like FIG. 3(a), FIG. 8(a) illustrates a state in which the first battery module 21 and the second battery module 31 are being charged. The first parallel relay 22 and the second parallel relay 32 are in the on state, and a charging current Ich flows from the input / output unit 13 to the battery unit. When charging of the first battery module 21 and the second battery module 31 is completed, a request to suppress the circulating current is generated, and the input / output control step controls the charging current Ich to gradually decrease toward the current command value Ich*, which corresponds to the circulating cancellation current value. As the charging current Ich gradually decreases toward the current command value Ich*, the first current value I1 and the second current value I2 also gradually decrease.

[0081] When |I1|≦X1 is satisfied, the first series relay 23 is switched on as shown in FIG. 8(b). Subsequently, the first parallel relay 22 is switched off as shown in FIG. 8(c). After that, when |I2|≦X2 is satisfied, the second series relay 33 is switched on, and then the second parallel relay 32 is switched off as shown in FIG. 8(d). Although not shown, the input / output current of the input / output unit 13 is then stopped, as in FIG. 3(d). When the potential of the multiple resistor-equipped battery packs constituting the battery unit is high, the large current that flows when input / output power is stopped can be effectively suppressed by configuring multiple resistors (first resistor 24 and second resistor 34) to switch the relay related to the potential adjustment sequence. For example, multiple potential thresholds with different magnitudes may be set for the potential of the multiple resistor-equipped battery packs constituting the battery unit. The number of resistors used to switch the relay related to the potential adjustment sequence may be increased as the potential exceeds a higher potential threshold.

[0082] (Variation) In the above-described embodiments, the input / output unit 13 is a charge / discharge device, but is not limited thereto. For example, as shown in FIG. 9 , the input / output unit 13 may be a DC-DC converter 93 connected to a vehicle auxiliary battery 94. Alternatively, the input / output unit 13 may be an air compressor, a heater, or other load. As described above, the input / output unit in the present application is not limited to a configuration capable of both input and output, and may be a configuration having only one of the input and output functions.

[0083] In addition, in the above-described embodiments, the battery unit is configured by resistor-equipped battery packs connected in parallel to each other, but this is not limiting. For example, as shown in Fig. 10, the battery unit may be configured by connecting in parallel a battery pack similar to the first battery pack 20 and a battery pack that does not include a resistor, a series relay, or a parallel relay and includes only a battery module 51. It is sufficient that at least one resistor-equipped battery pack is included in the parallel-connected battery packs that make up the battery unit.

[0084] Furthermore, as shown in FIG. 11 , the battery unit may be configured to switch the connection state of each battery pack between parallel and series. In this case, when the battery packs are connected in parallel, the battery control method described above can be applied. As shown in FIG. 11 , the left battery pack including a battery module 61, a parallel relay 62, a series relay 63, and a resistor 64 is connected to the right battery pack including a battery module 71, a parallel relay 72, a series relay 73, and a resistor 74 via relays 81 to 83. The relay 81 connects the high-potential sides of the battery packs to each other. The relay 82 connects the low-potential sides of the battery packs to each other. The relay 83 connects the low-potential side of the battery module 61 to the high-potential sides of the parallel relay 72 and the series relay 73 to each other. The wiring 84 connects the high-potential side of the input / output unit 13 to the high-potential sides of the parallel relay 62 and the series relay 63 to each other. The battery packs can be connected in parallel by turning relay 83 off and relays 81 and 82 on. The battery packs can be connected in series by turning relay 83 on and relays 81 and 82 off.

[0085] According to each of the above embodiments, the following effects can be obtained.

[0086] The battery control device 9 controls a battery circuit 10 including a battery section in which a plurality of battery packs (first to third battery packs 20, 30, 40) including at least battery modules (first to third battery modules 21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section 13 that inputs and outputs power to the battery section. At least one of the plurality of battery packs is a resistor-equipped battery pack including resistors (first to third resistors 24, 34, 44) connected in series to the battery modules, series relays (first to third series relays 23, 33, 43) connected in series to the resistors to switch the wiring connection on and off, and parallel relays (first to third series relays 22, 32, 43) connected in parallel to the resistors and series relays to switch the wiring connection on and off.

[0087] The battery control device 9 includes a relay control unit 15 that controls the on / off of the series relay and the parallel relay, and an input / output control unit 16 that controls the input / output power between the input / output unit 13 and the battery unit. When the relay control unit 15 executes a potential adjustment sequence that adjusts the potential between multiple battery packs by controlling the on / off of the series relay and the parallel relay, the input / output control unit 16 controls the input / output unit 13 to input / output power adjusted to suppress the circulating current based on the circulating current direction, i.e., the current direction of the circulating current flowing between the multiple battery packs, and the magnitude of the circulating current. This allows the potential adjustment sequence to be executed by controlling the on / off of the series relay and the parallel relay while suppressing the circulating current, thereby reducing the load on the relay when switching the relay to adjust the potential of the battery circuit 10. As a result, the life of the relay can be extended, contributing to reduced replacement costs. Furthermore, the capacity of the relay can be reduced, contributing to reduced component costs.

[0088] In the potential adjustment sequence, when the current flowing through at least one of the resistor-equipped battery packs becomes equal to or less than a predetermined switching current threshold, the relay control unit 15 switches the series relay to the ON state and then switches the parallel relay to the OFF state. This allows each relay to be switched while suppressing the load on each relay, thereby ensuring the life of the relay.

[0089] When the input / output control unit controls the input / output unit so that a discharge current flows from the battery unit, the relay control unit 15 switches the current path by controlling a series relay or a parallel relay included in the resistor-equipped battery pack in which the circulating current has a charging direction. Also, when the input / output control unit controls the input / output unit so that a charging current flows to the battery unit, the relay control unit 15 switches the current path by controlling a series relay or a parallel relay included in the resistor-equipped battery pack in which the circulating current has a discharging direction. By switching the current path so that the current directions of the circulating current and the input / output power are opposite, the input / output power can be used as a circulating canceling current.

[0090] The battery unit may include at least three resistor-equipped battery packs connected in parallel. In this case, the input / output control unit 16 is preferably configured to control the input / output power of the input / output unit so that the current flowing through the resistor-equipped battery pack with the smallest circulating current among the at least three resistor-equipped battery packs included in the battery unit is equal to or less than the switching current threshold. This makes it possible to execute the potential adjustment sequence by minimizing the input / output power of the input / output unit 13. Furthermore, the input / output control unit 16 may be configured to determine whether the current from the input / output unit to the battery unit is a charging current or a discharging current, depending on the direction of the current flowing through the series relay or parallel relay included in the resistor-equipped battery pack with the smallest circulating current.

[0091] After the relay control unit 15 switches the series relays to the ON state and the parallel relays to the OFF state, the input / output control unit 16 may be configured to control the input / output unit 13 to stop the input / output of power adjusted to suppress the circulating current. Since the input / output current is stopped after the current path is made to include resistance, it is possible to suppress a large current that flows when the input / output current is stopped.

[0092] The resistance of the resistor in the battery pack may be adjustable based on a predetermined battery parameter that affects the circulating current, thereby effectively reducing the circulating current and shortening the time required for potential adjustment.

[0093] The input / output control unit 16 may be configured to estimate the direction and magnitude of the circulating current based on the voltage of the battery module or the voltage of the battery pack and the internal resistance of the battery module, and to control the input / output unit 13 to input or output power adjusted to suppress the circulating current when the circulating current exceeds the upper limit of the chargeable / dischargeable current of the battery module. This can reduce the current value flowing as the circulating current and shorten the time required for potential adjustment.

[0094] When the battery module includes at least two resistor-equipped battery packs connected in parallel, the relay control unit 15 may be configured to change the potential adjustment sequence in response to a load request from the battery module when the series relay is turned on and the parallel relay is turned off, causing a circulating current to flow through the resistor. Specifically, for example, when there is a load request from the battery module, the relay control unit 15 may be configured to terminate the potential adjustment sequence by switching the parallel relay on and then off. This allows the battery module to discharge current from the parallel relay, which does not include a resistor in the current path, in response to a load request. Furthermore, when there is no load request from the battery module, the relay control unit 15 may be configured to terminate the potential adjustment sequence by switching the series relay off. This avoids unnecessary execution of a process of switching the parallel relay on. Furthermore, the relay control unit 15 may be configured to estimate a circulating current when the parallel relay is turned on while the series relay is on, and to switch the parallel relay on when the estimated circulating current is equal to or less than the upper limit of the chargeable / dischargeable current of the battery module. The current value flowing as a circulating current can be reduced, and the time required for potential adjustment can be shortened.

[0095] If a load request is made from the battery unit while the series relay is in the ON state, the input / output control unit 16 controls the input / output unit 13 to input or output power adjusted to suppress circulating current, and the relay control unit 15 may be configured to turn the series relay off and then turn the parallel relay on. Since the relays can be switched while suppressing circulating current, the load on each relay can be suppressed and the life of the relays can be secured.

[0096] The battery control device 9 may be configured to execute a battery control program to perform the battery control processes executed by the components described above. This battery control program causes the computer to execute a relay control step of controlling the on / off of the series relay and the parallel relay, and an input / output control step of controlling the input / output power between the input / output unit 13 and the battery unit. When a potential adjustment sequence for adjusting the potential between the multiple battery packs is executed by controlling the on / off of the series relay and the parallel relay in the relay control step, the input / output control step controls the input / output unit 13 to input / output power adjusted to suppress the circulating current based on the circulating current direction, which is the current direction of the circulating current flowing between the multiple battery packs, and the magnitude of the circulating current.

[0097] The controller and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the controller and methods described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the controller and methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0098] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] A battery control device (9) controls a battery circuit (10) including a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, at least one of the plurality of battery packs is a resistor-equipped battery pack including a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on / off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on / off a wiring connection, a relay control unit (15) that controls the on / off of the series relay and the parallel relay; an input / output control unit (16) that controls input / output power between the input / output unit and the battery unit, The input / output control unit controls the input / output unit to input and output power adjusted to suppress the circulating current based on the circulating current direction, which is the current direction of the circulating current flowing between the plurality of battery packs, and the magnitude of the circulating current, when the relay control unit executes a potential adjustment sequence to adjust the potential between the plurality of battery packs by on / off control of the series relay and the parallel relay. [Configuration 2] The battery control device according to configuration 1, wherein the relay control unit switches the series relay to an ON state and then switches the parallel relay to an OFF state when a current flowing through at least one of the resistor-equipped battery packs becomes equal to or less than a predetermined switching current threshold during the potential adjustment sequence. [Configuration 3] The battery control device according to configuration 2, wherein the relay control unit switches the current path by controlling the series relay or the parallel relay included in the resistor-equipped battery pack in which the circulating current has a charging direction when the input / output control unit controls the input / output unit so that a discharging current flows from the battery unit. [Configuration 4] The battery control device according to configuration 2, wherein the relay control unit switches the current path by controlling the series relay or the parallel relay included in the resistor-equipped battery pack in which the circulating current is in the discharging direction when the input / output control unit controls the input / output unit so that a charging current flows to the battery unit. [Configuration 5] the battery unit includes at least three of the resistor-equipped battery packs connected in parallel with each other, The battery control device according to configuration 2, wherein the input / output control unit controls the input / output power of the input / output unit so that the current flowing through the resistor-equipped battery pack having the smallest circulating current among the at least three resistor-equipped battery packs included in the battery unit is equal to or less than the switching current threshold. [Configuration 6] The battery control device according to configuration 5, wherein the input / output control unit determines whether the current from the input / output unit to the battery unit is a charging current or a discharging current depending on the current direction of the current flowing through the series relay or the parallel relay included in the resistor-equipped battery pack in which the magnitude of the circulating current is minimum. [Configuration 7] The battery control device according to any one of configurations 2 to 6, wherein after the relay control unit switches the series relay to an on state and switches the parallel relay to an off state, the input / output control unit controls the input / output unit to stop inputting and outputting power adjusted to suppress the circulating current. [Configuration 8] 8. The battery control device according to any one of configurations 1 to 7, wherein the resistor included in the resistor-equipped battery pack has a resistance value that can be adjusted based on a predetermined battery parameter that affects the circulating current. [Configuration 9] The battery control device according to any one of configurations 1 to 8, wherein the input / output control unit estimates the direction and magnitude of the circulating current based on the voltage of the battery module or the voltage of the battery pack and the internal resistance of the battery module, and controls the input / output unit to input / output power adjusted to suppress the circulating current when the circulating current exceeds an upper limit value of the chargeable / dischargeable current of the battery module. [Configuration 10] the battery unit includes at least two of the resistor-equipped battery packs connected in parallel with each other, The battery control device according to any one of configurations 1 to 9, wherein the relay control unit changes the potential adjustment sequence in accordance with a load request of the battery unit when the series relay is turned on and the parallel relay is turned off so that the circulating current flows through the resistor. [Configuration 11] 11. The battery control device according to claim 10, wherein the relay control unit, when there is a load request from the battery unit, ends the potential adjustment sequence by switching the parallel relay to an on state and then switching the series relay to an off state. [Configuration 12] 11. The battery control device according to claim 10, wherein the relay control unit ends the potential adjustment sequence by switching the series relay to an OFF state when there is no load request from the battery unit. [Configuration 13] 11. The battery control device according to claim 10, wherein the relay control unit estimates an estimated value of the circulating current when the parallel relay is switched to an on state while the series relay is in an on state, and switches the parallel relay to an on state when the estimated value of the circulating current becomes equal to or less than an upper limit value of the chargeable / dischargeable current of the battery module. [Configuration 14] 11. A battery control device according to claim 10, wherein when a load request is made to the battery unit while the series relay is in an on state, the input / output control unit controls the input / output unit to input / output power adjusted to suppress the circulating current, and the relay control unit turns the series relay off and then turns the parallel relay on. [Configuration 15] A battery control program applied to a battery control device (9) for controlling a battery circuit (10) including a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, at least one of the plurality of battery packs being a resistor-equipped battery pack (20, 30, 40) including a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on / off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on / off the wiring connection, the battery control program being configured to include: a relay control step of controlling the series relay and the parallel relay to be turned on and off; an input / output control step of controlling input / output power between the input / output unit and the battery unit; The input / output control step is a battery control program that, when a potential adjustment sequence is executed in the relay control step to adjust the potential between the plurality of battery packs by controlling the series relay and the parallel relay on and off, controls the input / output unit to input and output power adjusted to suppress the circulating current based on the circulating current direction, which is the current direction of the circulating current flowing between the plurality of battery packs, and the magnitude of the circulating current. [Explanation of symbols]

[0099] 9. Battery control device, 10. Battery circuit, 13. Input / output section, 15. Relay control section, 16. Input / output control section, 20. First battery pack, 21. First battery module, 22. First parallel relay, 23. First series relay, 24. First resistor, 30. Second battery pack, 31. Second battery module, 22. Second parallel relay, 23. Second series relay, 24. Second resistor

Claims

1. A battery control device (9) for controlling a battery circuit (10) including a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, At least one of the plurality of battery packs is a resistor-equipped battery pack including a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on and off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on and off a wiring connection, a relay control unit (15) that controls the on / off of the series relay and the parallel relay; an input / output control unit (16) that controls input / output power between the input / output unit and the battery unit, when the relay control unit executes a potential adjustment sequence for adjusting a potential between the plurality of battery packs by controlling on and off of the series relays and the parallel relays, the input / output control unit calculates a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, based on a circulating current direction that is a current direction of the circulating current flowing between the plurality of battery packs and a magnitude of the circulating current, and controls the input / output unit to input and output power adjusted to suppress the circulating current, based on the calculated current command value; When the input / output control unit controls the input / output unit so that a discharge current flows from the battery unit to the input / output unit in order to suppress the circulating current, if the current flowing through the resistor-equipped battery pack in which the circulating current has a charging direction becomes equal to or less than a switching current threshold in the potential adjustment sequence, the relay control unit switches the series relay included in the resistor-equipped battery pack in which the circulating current has a charging direction to an on state, and then switches the parallel relay included in the resistor-equipped battery pack in which the circulating current has a charging direction to an off state.

2. A battery control device (9) for controlling a battery circuit (10) including a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, At least one of the plurality of battery packs is a resistor-equipped battery pack including a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on and off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on and off a wiring connection, a relay control unit (15) that controls the on / off of the series relay and the parallel relay; an input / output control unit (16) that controls input / output power between the input / output unit and the battery unit, when the relay control unit executes a potential adjustment sequence for adjusting a potential between the plurality of battery packs by controlling on and off of the series relays and the parallel relays, the input / output control unit calculates a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, based on a circulating current direction that is a current direction of the circulating current flowing between the plurality of battery packs and a magnitude of the circulating current, and controls the input / output unit to input and output power adjusted to suppress the circulating current, based on the calculated current command value; When the input / output control unit controls the input / output unit so that a charging current flows from the input / output unit to the battery unit in order to suppress the circulating current, if the current flowing through the resistor-equipped battery pack in which the circulating current is in the discharging direction becomes equal to or less than a switching current threshold in the potential adjustment sequence, the relay control unit switches the series relay included in the resistor-equipped battery pack in which the circulating current is in the discharging direction to an on state, and then switches the parallel relay included in the resistor-equipped battery pack in which the circulating current is in the discharging direction to an off state.

3. A battery control device (9) for controlling a battery circuit (10) including a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, At least one of the plurality of battery packs is a resistor-equipped battery pack including a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on and off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on and off a wiring connection, a relay control unit (15) for controlling the on / off of the series relay and the parallel relay; an input / output control unit (16) that controls input / output power between the input / output unit and the battery unit, when the relay control unit executes a potential adjustment sequence for adjusting a potential between the plurality of battery packs by controlling on and off of the series relays and the parallel relays, the input / output control unit calculates a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, based on a circulating current direction that is a current direction of the circulating current flowing between the plurality of battery packs and a magnitude of the circulating current, and controls the input / output unit to input and output power adjusted to suppress the circulating current, based on the calculated current command value; the relay control unit switches the series relay to an ON state and then switches the parallel relay to an OFF state when a current flowing through at least one of the resistor-equipped battery packs becomes equal to or less than a predetermined switching current threshold in the potential adjustment sequence; a battery control device in which, after the relay control unit switches the series relay to an on state and the parallel relay to an off state, the input / output control unit controls the input / output unit to stop inputting and outputting power adjusted to suppress the circulating current.

4. A battery control device (9) for controlling a battery circuit (10) including a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, At least one of the plurality of battery packs is a resistor-equipped battery pack including a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on and off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on and off a wiring connection, a relay control unit (15) for controlling the on / off of the series relay and the parallel relay; an input / output control unit (16) that controls input / output power between the input / output unit and the battery unit, when the relay control unit executes a potential adjustment sequence for adjusting a potential between the plurality of battery packs by controlling on and off of the series relays and the parallel relays, the input / output control unit calculates a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, based on a circulating current direction that is a current direction of the circulating current flowing between the plurality of battery packs and a magnitude of the circulating current, and controls the input / output unit to input and output power adjusted to suppress the circulating current, based on the calculated current command value; The input / output control unit estimates the direction and magnitude of the circulating current based on the voltage of the battery module or the voltage of the battery pack and the internal resistance of the battery module, and controls the input / output unit to input and output power adjusted to suppress the circulating current when the circulating current exceeds an upper limit value of the charge / discharge current of the battery module.

5. A battery control device (9) for controlling a battery circuit (10) including a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, At least one of the plurality of battery packs is a resistor-equipped battery pack including a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on and off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on and off a wiring connection, a relay control unit (15) for controlling the on / off of the series relay and the parallel relay; an input / output control unit (16) that controls input / output power between the input / output unit and the battery unit, when the relay control unit executes a potential adjustment sequence for adjusting a potential between the plurality of battery packs by controlling on and off of the series relays and the parallel relays, the input / output control unit calculates a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, based on a circulating current direction that is a current direction of the circulating current flowing between the plurality of battery packs and a magnitude of the circulating current, and controls the input / output unit to input and output power adjusted to suppress the circulating current, based on the calculated current command value; the battery unit includes at least two of the resistor-equipped battery packs connected in parallel with each other, The relay control unit changes the potential adjustment sequence in accordance with a load request of the battery unit when the series relay is turned on and the parallel relay is turned off so that the circulating current flows through the resistor.

6. 6. The battery control device according to claim 5, wherein, when there is a load request from the battery unit, the relay control unit switches the parallel relay to an ON state and then switches the series relay to an OFF state, thereby ending the potential adjustment sequence.

7. The battery control device according to claim 5 , wherein the relay control unit ends the potential adjustment sequence by switching the series relay to an OFF state when there is no load request from the battery unit.

8. 6. The battery control device according to claim 5, wherein the relay control unit estimates an estimated value of the circulating current when the parallel relay is switched to an on state while the series relay is in an on state, and switches the parallel relay to an on state when the estimated value of the circulating current becomes equal to or less than an upper limit value of a charge / discharge current of the battery module.

9. 6. The battery control device according to claim 5, wherein when a load request is made for the battery unit while the series relay is in an on state, the input / output control unit controls the input / output unit to input / output power adjusted to suppress the circulating current, and the relay control unit turns the series relay to an off state and then turns the parallel relay to an on state.

10. A battery control program applied to a battery control device (9) for controlling a battery circuit (10) including a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, wherein at least one of the plurality of battery packs is a resistor-equipped battery pack (20, 30, 40) including a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on and off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on and off the wiring connection, the battery control program being programmed to a computer: a relay control step of controlling the series relay and the parallel relay to be turned on and off; an input / output control step of controlling input / output power between the input / output unit and the battery unit; the input / output control step is a step of calculating, based on a circulating current direction that is a current direction of a circulating current flowing among the plurality of battery packs and a magnitude of the circulating current, a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, when a potential adjustment sequence for adjusting a potential between the plurality of battery packs is executed by controlling on / off of the series relay and the parallel relay in the relay control step, and controlling the input / output unit to input or output power adjusted to suppress the circulating current based on the calculated current command value; the relay control step is a step of switching on the series relay included in the resistor-equipped battery pack in which the circulating current has a charging direction to an on state and then switching off the parallel relay included in the resistor-equipped battery pack in which the circulating current has a charging direction to an off state when, in the potential adjustment sequence, the current flowing through the resistor-equipped battery pack in which the circulating current has a charging direction becomes equal to or less than a switching current threshold, when the input / output unit is controlled by the input / output control step so that a discharge current flows from the battery unit to the input / output unit in order to suppress the circulating current.

11. A battery circuit comprising a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, wherein at least one of the plurality of battery packs is a resistor-equipped battery pack comprising a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on / off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on / off a wiring connection, the battery control program being applied to a battery control device (9) that controls the battery circuit (10), a relay control step of controlling the series relay and the parallel relay to be turned on and off; an input / output control step of controlling input / output power between the input / output unit and the battery unit; the input / output control step is a step of calculating, based on a circulating current direction that is a current direction of a circulating current flowing among the plurality of battery packs and a magnitude of the circulating current, a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, when a potential adjustment sequence for adjusting a potential between the plurality of battery packs is executed by controlling on / off of the series relay and the parallel relay in the relay control step, and controlling the input / output unit to input / output power adjusted to suppress the circulating current based on the calculated current command value; The relay control step is a step of switching on the series relay included in the resistor-equipped battery pack in which the circulating current is in the discharging direction and then switching off the parallel relay included in the resistor-equipped battery pack in which the circulating current is in the discharging direction when the input / output control step controls the input / output unit so that a charging current flows from the input / output unit to the battery unit in order to suppress the circulating current.

12. A battery circuit comprising a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, wherein at least one of the plurality of battery packs is a resistor-equipped battery pack comprising a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on / off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on / off a wiring connection, the battery control program being applied to a battery control device (9) that controls the battery circuit (10), a relay control step of controlling the series relay and the parallel relay to be turned on and off; an input / output control step of controlling input / output power between the input / output unit and the battery unit; the input / output control step is a step of calculating, based on a circulating current direction that is a current direction of a circulating current flowing among the plurality of battery packs and a magnitude of the circulating current, a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, when a potential adjustment sequence for adjusting a potential between the plurality of battery packs is executed by controlling on / off of the series relay and the parallel relay in the relay control step, and controlling the input / output unit to input / output power adjusted to suppress the circulating current based on the calculated current command value; the relay control step is a step of switching the series relay to an ON state and then switching the parallel relay to an OFF state when a current flowing through at least one of the resistor-equipped battery packs becomes equal to or less than a predetermined switching current threshold in the potential adjustment sequence; a battery control program for controlling the input / output unit to stop input / output of power adjusted to suppress the circulating current after the series relay is switched to an on state and the parallel relay is switched to an off state in the relay control step;

13. A battery circuit comprising a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, wherein at least one of the plurality of battery packs is a resistor-equipped battery pack comprising a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on / off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on / off a wiring connection, the battery control program being applied to a battery control device (9) that controls the battery circuit (10), a relay control step of controlling the series relay and the parallel relay to be turned on and off; an input / output control step of controlling input / output power between the input / output unit and the battery unit; the input / output control step is a step of calculating, based on a circulating current direction that is a current direction of a circulating current flowing among the plurality of battery packs and a magnitude of the circulating current, a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, when a potential adjustment sequence for adjusting a potential between the plurality of battery packs is executed by controlling on / off of the series relay and the parallel relay in the relay control step, and controlling the input / output unit to input / output power adjusted to suppress the circulating current based on the calculated current command value; The input / output control step is a step of estimating the direction and magnitude of the circulating current based on the voltage of the battery module or the voltage of the battery pack and the internal resistance of the battery module, and controlling the input / output unit to input and output power adjusted to suppress the circulating current when the circulating current exceeds an upper charge / discharge current limit value of the battery module.

14. A battery circuit comprising a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, wherein at least one of the plurality of battery packs is a resistor-equipped battery pack comprising a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on / off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on / off a wiring connection, the battery control program being applied to a battery control device (9) that controls the battery circuit (10), a relay control step of controlling the series relay and the parallel relay to be turned on and off; an input / output control step of controlling input / output power between the input / output unit and the battery unit; the input / output control step is a step of calculating, based on a circulating current direction that is a current direction of a circulating current flowing among the plurality of battery packs and a magnitude of the circulating current, a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, when a potential adjustment sequence for adjusting a potential between the plurality of battery packs is executed by controlling on / off of the series relay and the parallel relay in the relay control step, and controlling the input / output unit to input / output power adjusted to suppress the circulating current based on the calculated current command value; the battery unit includes at least two of the resistor-equipped battery packs connected in parallel with each other, a battery control program for changing the potential adjustment sequence in accordance with a load request of the battery module when, in the relay control step, the series relay is turned on and the parallel relay is turned off so that the circulating current flows through the resistor.

15. A battery control method applied to a battery circuit (10) comprising a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, wherein at least one of the plurality of battery packs is a resistor-equipped battery pack (20, 30, 40) that comprises a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on / off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on / off a wiring connection, the method comprising: a relay control step of controlling the series relay and the parallel relay to be turned on and off; an input / output control step of controlling input / output power between the input / output unit and the battery unit; the input / output control step is a step of calculating, based on a circulating current direction that is a current direction of a circulating current flowing among the plurality of battery packs and a magnitude of the circulating current, a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, when a potential adjustment sequence for adjusting a potential between the plurality of battery packs is executed by controlling on / off of the series relay and the parallel relay in the relay control step, and controlling the input / output unit to input or output power adjusted to suppress the circulating current based on the calculated current command value; the relay control step is a step of switching on the series relay included in the resistor-equipped battery pack in which the circulating current has a charging direction to an on state and then switching off the parallel relay included in the resistor-equipped battery pack in which the circulating current has a charging direction to an off state when, in the potential adjustment sequence, the current flowing through the resistor-equipped battery pack in which the circulating current has a charging direction becomes equal to or less than a switching current threshold, when the input / output unit is controlled by the input / output control step so that a discharge current flows from the battery unit to the input / output unit in order to suppress the circulating current.

16. A battery circuit comprising a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, wherein at least one of the plurality of battery packs is a resistor-equipped battery pack (10) that comprises a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on / off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on / off a wiring connection, the battery control method being applied to a battery circuit (10) that comprises: a relay control step of controlling the series relay and the parallel relay to be turned on and off; an input / output control step of controlling input / output power between the input / output unit and the battery unit; the input / output control step is a step of calculating, based on a circulating current direction that is a current direction of a circulating current flowing among the plurality of battery packs and a magnitude of the circulating current, a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, when a potential adjustment sequence for adjusting a potential between the plurality of battery packs is executed by controlling on / off of the series relay and the parallel relay in the relay control step, and controlling the input / output unit to input / output power adjusted to suppress the circulating current based on the calculated current command value; The relay control step is a step of switching on the series relay included in the resistor-equipped battery pack in which the circulating current is in the discharging direction, and then switching off the parallel relay included in the resistor-equipped battery pack in which the circulating current is in the discharging direction, when the input / output control step controls the input / output unit so that a charging current flows from the input / output unit to the battery unit in order to suppress the circulating current, when the current flowing through the resistor-equipped battery pack in which the circulating current is in the discharging direction becomes equal to or less than a switching current threshold in the potential adjustment sequence.

17. A battery circuit comprising a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, wherein at least one of the plurality of battery packs is a resistor-equipped battery pack (10) that comprises a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on / off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on / off a wiring connection, the battery control method being applied to a battery circuit (10) that comprises: a relay control step of controlling the series relay and the parallel relay to be turned on and off; an input / output control step of controlling input / output power between the input / output unit and the battery unit; the input / output control step is a step of calculating, based on a circulating current direction that is a current direction of a circulating current flowing among the plurality of battery packs and a magnitude of the circulating current, a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, when a potential adjustment sequence for adjusting a potential between the plurality of battery packs is executed by controlling on / off of the series relay and the parallel relay in the relay control step, and controlling the input / output unit to input / output power adjusted to suppress the circulating current based on the calculated current command value; the relay control step is a step of switching the series relay to an ON state and then switching the parallel relay to an OFF state when a current flowing through at least one of the resistor-equipped battery packs becomes equal to or less than a predetermined switching current threshold in the potential adjustment sequence; a relay control step of switching the series relay to an on state and the parallel relay to an off state, and then, in the input / output control step, controlling the input / output unit to stop input / output of power adjusted to suppress the circulating current.

18. A battery circuit comprising a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, wherein at least one of the plurality of battery packs is a resistor-equipped battery pack (10) that comprises a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on / off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on / off a wiring connection, the battery control method being applied to a battery circuit (10) that comprises: a relay control step of controlling the series relay and the parallel relay to be turned on and off; an input / output control step of controlling input / output power between the input / output unit and the battery unit; the input / output control step is a step of calculating, based on a circulating current direction that is a current direction of a circulating current flowing among the plurality of battery packs and a magnitude of the circulating current, a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, when a potential adjustment sequence for adjusting a potential between the plurality of battery packs is executed by controlling on / off of the series relay and the parallel relay in the relay control step, and controlling the input / output unit to input / output power adjusted to suppress the circulating current based on the calculated current command value; The input / output control step is a step of estimating the direction and magnitude of the circulating current based on the voltage of the battery module or the voltage of the battery pack and the internal resistance of the battery module, and controlling the input / output unit to input and output power adjusted to suppress the circulating current when the circulating current exceeds an upper charge / discharge current limit value of the battery module.

19. A battery circuit comprising a battery section in which a plurality of battery packs (20, 30, 40) including at least battery modules (21, 31, 41) that are secondary batteries are connected in parallel, and an input / output section (13) that inputs and outputs power to the battery section, wherein at least one of the plurality of battery packs is a resistor-equipped battery pack (10) that comprises a resistor (24, 34, 44) connected in series to the battery module, a series relay (23, 33, 43) connected in series to the resistor for switching on / off a wiring connection, and a parallel relay (22, 32, 42) connected in parallel to the resistor and the series relay for switching on / off a wiring connection, the battery control method being applied to a battery circuit (10) that comprises: a relay control step of controlling the series relay and the parallel relay to be turned on and off; an input / output control step of controlling input / output power between the input / output unit and the battery unit; the input / output control step is a step of calculating, based on a circulating current direction that is a current direction of a circulating current flowing among the plurality of battery packs and a magnitude of the circulating current, a current command value that is opposite to the circulating current direction and that is for suppressing the circulating current, when a potential adjustment sequence for adjusting a potential between the plurality of battery packs is executed by controlling on / off of the series relay and the parallel relay in the relay control step, and controlling the input / output unit to input / output power adjusted to suppress the circulating current based on the calculated current command value; the battery unit includes at least two of the resistor-equipped battery packs connected in parallel with each other, a battery control method in which, in the relay control step, when the series relay is turned on and the parallel relay is turned off so that the circulating current flows through the resistor, the potential adjustment sequence is changed in accordance with a load request of the battery unit.

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