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

Abstract

To provide a battery control device, battery control system, control method, and control program capable of preventing over-discharge of a secondary battery even if an abnormality occurs in the opening function of a switch connected to the secondary battery. [Solution] The battery control device 10 includes an opening function abnormality determination unit 103 that determines whether there is an abnormality in the opening function of a switch 3 connected to a plurality of secondary batteries 2 connected in series; a voltage determination unit 104 that determines, if an abnormality in the opening function is determined, whether the measured voltage of each of the plurality of secondary batteries 2 is less than or equal to a first voltage threshold that is greater than the over-discharge voltage corresponding to the over-discharge state of the secondary battery 2; and a cell balancing processing unit 106 that performs a cell balancing process to adjust the SOC or voltage of the plurality of secondary batteries 2 so that the SOC or measured voltage of the plurality of secondary batteries 2 is the same, if it is determined that the measured voltage of at least one of the plurality of secondary batteries 2 is less than or equal to the first voltage threshold.

Description

Technical Field

[0001] The present disclosure relates to a battery control device, a battery control system, a control method, and a control program for controlling a plurality of secondary batteries.

Background Art

[0002] Conventionally, in a battery control system for controlling a plurality of secondary batteries, there is one having an open-circuit function for opening and closing a switch connected to these secondary batteries. Some such battery control systems do not communicate with a power supply destination system to which the secondary batteries supply power. In a battery control system that does not communicate with a power supply destination system, when an abnormality occurs in the open-circuit function of the switch, the discharge of the secondary battery continues, so there is a possibility that the secondary battery may enter an overdischarge state. In particular, when there are variations in the SOC (State Of Charge) of a plurality of secondary batteries, the secondary battery with a low SOC is likely to enter an overdischarge state.

[0003] Regarding this point, Patent Document 1 discloses a battery protection device that restricts the charge and discharge amount of a battery to protect the battery when an abnormality occurs in a voltage equalization device that equalizes the voltages of predetermined cells in the battery.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the battery protection device disclosed in Patent Document 1 has a problem that it cannot prevent the overdischarge of a secondary battery when an abnormality occurs in the open-circuit function of a switch connected to the secondary battery.

[0006] This disclosure is made to solve these problems and aims to provide a battery control device, battery control system, control method, and control program that can prevent over-discharge of a secondary battery even if an abnormality occurs in the opening function of a switch connected to the secondary battery. [Means for solving the problem]

[0007] The battery control device relating to this disclosure is A circuit opening function abnormality determination unit that determines whether there is an abnormality in the circuit opening function of a switch connected to multiple secondary batteries connected in series, If it is determined that there is an abnormality in the circuit opening function, a voltage determination unit determines whether the measured voltage of each of the multiple secondary batteries is below a first voltage threshold that is greater than the over-discharge voltage, which is the voltage corresponding to the over-discharge state of the secondary battery. It includes a cell balancing processing unit that performs a cell balancing process to adjust the SOC or voltage of multiple secondary batteries so that the SOC or measured voltage of multiple secondary batteries is the same, The cell balancing unit, when it determines that the measured voltage of at least one of the multiple secondary batteries is below a first voltage threshold, performs cell balancing to set the total voltage, which is the sum of the measured voltages of the multiple secondary batteries, to the shutdown voltage of the system powered by the multiple secondary batteries, before the State of Charge (SOC) or the voltage of the minimum secondary battery (the secondary battery with the lowest measured voltage) of the multiple secondary batteries reaches the over-discharge voltage.

[0008] If the cell balancing unit determines that the measured voltage of at least one of the multiple secondary batteries is below a first voltage threshold, it may perform a cell balancing process to discharge the secondary batteries other than the smallest secondary battery so that the state of charge (SOC) or measured voltage of the secondary batteries other than the smallest secondary battery approaches the SOC or measured voltage of the smallest secondary battery.

[0009] If the cell balancing unit determines that the measured voltage of at least one of the multiple secondary batteries is below a first voltage threshold, it may perform a cell balancing process in which it charges the secondary batteries with a lower SOC or measured voltage using the secondary batteries with a higher SOC or measured voltage among the multiple secondary batteries.

[0010] The cell balancing unit can continuously discharge multiple secondary batteries after performing the cell balancing process.

[0011] The system's shutdown voltage is greater than the sum of the over-discharge voltages of multiple secondary batteries.

[0012] Furthermore, the battery control device is If it is determined that there is no abnormality in the circuit opening function, the system includes a variation determination unit that determines whether there is variation in SOC or measured voltage among multiple secondary batteries by determining whether the difference between the maximum and minimum values ​​of the SOC of multiple secondary batteries, or the difference between the maximum and minimum values ​​of the measured voltage of multiple secondary batteries, is greater than or equal to a predetermined threshold. If it is determined that there is variation in the State of Charge (SOC) or measured voltage among multiple secondary batteries, the voltage determination unit determines whether the measured voltage of each of the multiple secondary batteries is greater than or equal to a second voltage threshold which is greater than the first voltage threshold. If it is determined that the measured voltage of at least one of the multiple secondary batteries is equal to or greater than a second voltage threshold, the cell balancing unit may perform a cell balancing process in which it charges the secondary batteries with the lower SOC or measured voltage using the secondary batteries with the higher SOC or measured voltage among the multiple secondary batteries.

[0013] The battery control system relating to this disclosure is A control device for controlling multiple secondary batteries connected in series, It includes a cell balancing circuit connected to each of the multiple secondary batteries, The control device is A circuit opening function abnormality determination unit that determines whether there is an abnormality in the circuit opening function of a switch connected to multiple secondary batteries, If it is determined that there is an abnormality in the circuit opening function, a voltage determination unit determines whether the measured voltage of each of the multiple secondary batteries is below a first voltage threshold that is greater than the over-discharge voltage, which is the voltage corresponding to the over-discharge state of the secondary battery. It includes a cell balancing processing unit that performs a cell balancing process to adjust the SOC or voltage of multiple secondary batteries so that the SOC or measured voltage of multiple secondary batteries is the same, If the cell balancing unit determines that the measured voltage of at least one of the multiple secondary batteries is below a first voltage threshold, it instructs the cell balancing circuit to perform cell balancing processing so that the total voltage, which is the sum of the measured voltages of the multiple secondary batteries, becomes the shutdown voltage of the system powered by the multiple secondary batteries, before the State of Charge (SOC) or the voltage of the secondary battery with the lowest measured voltage becomes the over-discharge voltage.

[0014] The control method for controlling multiple secondary batteries connected in series according to this disclosure is a computer that controls Determine if there is an abnormality in the opening function of the switch connected to multiple secondary batteries connected in series. If an abnormality is detected in the circuit opening function, it is determined whether the measured voltage of each of the multiple secondary batteries is below a first voltage threshold that is greater than the over-discharge voltage, which is the voltage corresponding to the over-discharge state of the secondary battery. If it is determined that the measured voltage of at least one of the multiple secondary batteries is below a first voltage threshold, a cell balancing process is performed to adjust the SOC or voltage of the multiple secondary batteries so that the SOC or measured voltage of the multiple secondary batteries is the same. The total voltage, which is the sum of the measured voltages of the multiple secondary batteries, is set to the shutdown voltage of the system powered by the multiple secondary batteries before the voltage of the smallest secondary battery (the secondary battery with the lowest SOC or measured voltage) reaches the over-discharge voltage.

[0015] The control program for controlling multiple secondary batteries connected in series according to this disclosure is provided to a computer, The system determines whether there is an abnormality in the opening function of the switch connected to multiple secondary batteries connected in series. When it is determined that an abnormality has occurred in the open-circuit function, it is determined whether the measured voltage of each of the plurality of secondary batteries is equal to or less than a first voltage threshold that is greater than the over-discharge voltage corresponding to the over-discharge state of the secondary battery. When it is determined that the measured voltage of at least one of the plurality of secondary batteries is equal to or less than the first voltage threshold, cell balancing processing is executed to adjust the SOC or voltage of the plurality of secondary batteries so that the SOC or measured voltage of the plurality of secondary batteries becomes the same, and before the voltage of the minimum secondary battery, which is the secondary battery with the minimum SOC or measured voltage among the plurality of secondary batteries, reaches the over-discharge voltage, the total voltage, which is the sum of the measured voltages of the plurality of secondary batteries, is set to the stop voltage of the system to which the plurality of secondary batteries supply power.

Advantages of the Invention

[0016] According to the present disclosure, it is possible to provide a battery control device, a battery control system, a control method, and a control program that can prevent over-discharge of a secondary battery even when an abnormality occurs in the open-circuit function of a switch connected to the secondary battery.

Brief Description of the Drawings

[0017] [Figure 1] It is a diagram showing an example of a battery control system according to the present disclosure. [Figure 2] It is a block diagram showing an example of the configuration of a control device according to the present disclosure. [Figure 3] It is a flowchart showing an example of the processing executed by the control device according to the present disclosure. [Figure 4] It is a flowchart showing an example of open-circuit function abnormality determination processing. [Figure 5] It is a diagram showing the concept of open-circuit function abnormality determination processing. [Figure 6] It is a diagram showing the change over time of the voltage of a secondary battery when the cell balancing processing according to the present disclosure is executed in the case where there is an abnormality in the open-circuit function. [Figure 7] It is a diagram showing the change over time of the voltage of a secondary battery when the cell balancing processing is not executed in the case where there is an abnormality in the open-circuit function. [Figure 8]This figure shows the change in the total voltage of multiple secondary batteries over time when there is an abnormality in the circuit opening function and cell balancing is not performed, and the change in the total voltage of multiple secondary batteries over time when cell balancing is performed and the multiple secondary batteries are continuously discharged. [Modes for carrying out the invention]

[0018] Figure 1 shows an example of a battery control system 1 according to this disclosure. The battery control system 1 is a system that controls multiple secondary batteries 2a and 2b connected in series. A specific example of the battery control system 1 is a battery management system installed in a vehicle. Although only two secondary batteries 2a and 2b are shown in Figure 1, the battery control system 1 can control three or more secondary batteries. Secondary batteries 2a and 2b can also be referred to as secondary battery 2, which may indicate one or more secondary batteries.

[0019] Multiple secondary batteries 2a and 2b are connected in series to a switch 3. When the switch 3 is closed, the multiple secondary batteries 2a and 2b supply power to the power supply system 4 via electrical wires 5 and 6. The battery control system 1 and the power supply system 4 according to this disclosure do not communicate with each other. Therefore, the battery control system 1 does not notify the power supply system 4 of information such as the status of the multiple secondary batteries 2 and the switch 3.

[0020] Multiple secondary batteries 2a and 2b are connected in series with a voltage sensor 13. The voltage sensor 13 measures the total voltage of the multiple secondary batteries 2a and 2b (hereinafter referred to as "total voltage") and provides the measured voltage value to the battery control system 1.

[0021] The battery control system 1 includes a control device 10, cell balancing circuits 11a and 11b, and voltage sensors 12a and 12b.

[0022] The cell balance circuits 11a and 11b, under the control of the control device 10, adjust the State of Charge (SOC) or measured voltage of multiple secondary batteries 2 to the secondary batteries 2a and 2b, respectively. The cell balance circuits 11a and 11b can also be referred to as cell balance circuit 11, which indicates one or more cell balance circuits.

[0023] Voltage sensors 12a and 12b measure the voltages of secondary batteries 2a and 2b, respectively, and provide the measured voltage values ​​to the battery control system 1. Voltage sensors 12a and 12b may also be referred to as voltage sensor 12, which indicates one or more voltage sensors.

[0024] Figure 2 is a block diagram showing an example of the configuration of the control device 10. The control device 10 comprises an arithmetic unit 100, input / output ports 110, and a storage device 120. The control device 10 corresponds to a battery control device.

[0025] The input / output port 110 is an interface for transmitting and receiving signals between the control device 10 and other devices, specifically the switch 3, the cell balance circuit 11, and the voltage sensors 12 and 13. The storage device 120 is a storage device that stores programs executed by the arithmetic unit 100 and various information processed by the arithmetic unit 100.

[0026] The arithmetic unit 100 is a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The arithmetic unit 100 executes the control method defined by the control program stored in the memory device 120. Alternatively, an integrated circuit such as an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit) may execute the control program. The processor, MPU, FPGA, and ASIC are equivalent to a computer.

[0027] The arithmetic unit 100 includes a switch control unit 101, a measurement voltage acquisition unit 102, an open circuit function abnormality determination unit 103, a voltage determination unit 104, a variation determination unit 105, and a cell balance processing unit 106. These functions can be implemented by program.

[0028] The switch control unit 101 controls the opening and closing of the switch 3 by sending an open signal or a closed signal to the switch 3.

[0029] The voltage measurement unit 102 acquires the measured voltage of the secondary battery 2 from the voltage sensors 12 and 13.

[0030] The circuit opening function abnormality determination unit 103 determines whether or not there is an abnormality in the circuit opening function of switch 3 and outputs the determination result.

[0031] The voltage determination unit 104 compares the measured voltage of the secondary battery 2 acquired by the voltage sensors 12 and 13 with a predetermined voltage.

[0032] The variation determination unit 105 determines whether or not there is variation in SOC among the multiple secondary batteries 2. Specifically, the variation determination unit 105 determines whether the difference between the SOC of the secondary battery with the smallest SOC and the SOC of the secondary battery with the largest SOC among the multiple secondary batteries 2 is greater than or equal to a predetermined value. The predetermined value can be any value. If this difference in SOC is greater than or equal to the predetermined value, the variation determination unit 105 determines that there is variation in SOC among the multiple secondary batteries 2.

[0033] In other embodiments, the variation determination unit 105 may determine whether or not there is variation in the measured voltage among the multiple secondary batteries 2. In this case, the variation determination unit 105 determines whether or not the difference between the measured voltage of the secondary battery with the lowest measured voltage and the measured voltage of the secondary battery with the highest measured voltage is greater than or equal to a predetermined value. If this difference in measured voltage is greater than or equal to a predetermined value, the variation determination unit 105 determines that there is variation in the State of Charge (SOC) among the multiple secondary batteries 2.

[0034] The cell balancing unit 106 performs cell balancing to adjust the SOC or measured voltage of multiple secondary batteries 2 so that the SOC or measured voltage of multiple secondary batteries 2 becomes the same. For example, a passive cell balancing method can be used as the cell balancing method. In the passive cell balancing method, the cell balancing circuit 11 discharges secondary batteries other than the minimum secondary battery so that the SOC or measured voltage of all secondary batteries 2 except the minimum secondary battery approaches the SOC or measured voltage of the minimum secondary battery. The cell balancing circuit 11 can discharge the secondary batteries 2 using elements such as resistors.

[0035] Alternatively, an active cell balancing method may be used as the cell balancing process. In the active cell balancing method, the cell balancing circuit 11 uses the secondary battery with the highest SOC or measured voltage among the multiple secondary batteries 2 to charge the secondary battery with the lowest SOC or measured voltage among the multiple secondary batteries 2.

[0036] Figure 3 is a flowchart showing an example of a process executed by the control device 10. In step S1, the circuit opening function abnormality determination unit 103 executes a circuit opening function abnormality determination process. Details of the circuit opening function abnormality determination process will be described later. In the process shown in Figure 3, in step S2, the process branches to either step S3 or step S7 depending on the result of the circuit opening function abnormality determination process. Specifically, if the result of the circuit opening function abnormality determination process indicates that there is an abnormality in the circuit opening function, the process branches to step S3. On the other hand, if the result of the circuit opening function abnormality determination process indicates that the circuit opening function is normal, the process branches to step S7.

[0037] In step S3, the measurement voltage acquisition unit 102 acquires the measurement voltage of each of the multiple secondary batteries 2. In step S4, the voltage determination unit 104 determines whether the acquired measurement voltage of each of the multiple secondary batteries 2 is below a first voltage threshold. As shown in Figure 6, the first voltage threshold is a voltage that is greater than the over-discharge voltage, which is the voltage corresponding to the over-discharge state of secondary batteries 2a and 2b, and less than the over-charge voltage, which is the voltage corresponding to the over-charge state of secondary batteries 2a and 2b. In addition, it is preferable that the first voltage threshold is a voltage in a capacity region where the voltage change in response to a change in the capacity of secondary batteries 2a and 2b is small, or a voltage in an SOC region where the voltage change in response to a change in SOC is small. In other words, it is preferable that the first voltage threshold is a voltage that is greater than or equal to the voltage at which the discharge rate of secondary batteries 2a and 2b (corresponding to the slope in Figure 6) is greater than or equal to a predetermined value. By setting this first voltage threshold, cell balancing is performed before the voltages of the secondary batteries 2a and 2b decrease rapidly, thus preventing the secondary batteries 2a and 2b from entering an over-discharge state.

[0038] If it is determined that the measured voltage of each of the multiple secondary batteries 2 exceeds the first voltage threshold (NO), the process returns to step S3. On the other hand, if it is determined that the measured voltage of at least one of the multiple secondary batteries 2 is below the first voltage threshold (YES), the cell balance processing unit 106 performs cell balance processing in step S5. In step S6, the cell balance processing unit 106 continues to discharge each secondary battery 2, and the process shown in Figure 2 is completed.

[0039] In step S7, the measurement voltage acquisition unit 102 acquires the measurement voltage of each of the multiple secondary batteries 2. In step S8, the variation determination unit 105 determines whether or not there is variation in the state of charge (SOC) among the multiple secondary batteries 2. If it is determined that there is no variation in the SOC (NO), the process returns to step S1. On the other hand, if it is determined that there is variation in the SOC (YES), the process branches to step S9.

[0040] In step S9, the voltage determination unit 104 determines whether the measured voltage of each of the acquired secondary batteries 2 is greater than or equal to a second voltage threshold which is greater than the first voltage threshold. If it is determined that the measured voltage of each of the multiple secondary batteries 2 is less than the second voltage threshold (NO), the process returns to step S1. On the other hand, if it is determined that the measured voltage of at least one of the multiple secondary batteries 2 is greater than or equal to the second voltage threshold (YES), in step S10, the cell balance processing unit 106 performs cell balance processing and the process returns to step S1.

[0041] Figure 4 is a flowchart showing an example of the process for determining abnormalities in the circuit opening function. Figure 5 is a diagram illustrating the concept of the process for determining abnormalities in the circuit opening function.

[0042] In step S11, the circuit opening function abnormality determination unit 103 transmits a circuit opening instruction signal to the switch 3, instructing it to open. In step S12, the measured voltage acquisition unit 102 acquires a measured voltage from the voltage sensor 13 that represents the total voltage of the multiple secondary batteries 2.

[0043] In step S13, the circuit opening function abnormality determination unit 103 determines whether the total voltage of the multiple secondary batteries 2 is equal to or greater than a predetermined voltage. The predetermined voltage is set to a value greater than the total voltage of the multiple secondary batteries 2 predicted when the switch 3 is opened. Specifically, for example, the predetermined voltage can be 10% of the total voltage of the multiple secondary batteries 2 when fully charged. As shown in Figure 5, if the circuit opening function is normal, the total voltage after sending the circuit opening instruction signal to the switch 3 will be lower than the predetermined voltage. On the other hand, if the circuit opening function is abnormal, the total voltage after sending the circuit opening instruction signal to the switch 3 will be higher than the predetermined voltage.

[0044] If the total voltage of the multiple secondary batteries 2 is determined to be above a predetermined voltage (YES), in step S14 the circuit opening function abnormality determination unit 103 outputs a result indicating that the circuit opening function is abnormal, and the circuit opening function abnormality determination process ends. On the other hand, if the total voltage of the multiple secondary batteries 2 is determined to be below a predetermined voltage (NO), in step S15 the circuit opening function abnormality determination unit 103 outputs a result indicating that the circuit opening function is normal, and the circuit opening function abnormality determination process ends.

[0045] As described above, the circuit opening function abnormality determination unit 103 determines whether there is an abnormality in the circuit opening function of the switch 3 connected to the multiple secondary batteries. If the voltage determination unit 104 determines that there is an abnormality in the circuit opening function, it determines whether the measured voltage of each of the multiple secondary batteries 2 is less than or equal to a first voltage threshold that is greater than the over-discharge voltage, which is the voltage corresponding to the over-discharge state of the individual secondary battery 2. If the cell balance processing unit 106 determines that the measured voltage of at least one of the multiple secondary batteries 2 is less than or equal to the first voltage threshold, it performs a cell balance processing to adjust the SOC or voltage of the multiple secondary batteries 2 so that the SOC or measured voltage of the multiple secondary batteries 2 is the same, and sets the total voltage, which is the sum of the measured voltages of the multiple secondary batteries 2, to the stop voltage of the power supply destination system 4 to which the multiple secondary batteries 2 supply power, before the voltage of the smallest secondary battery, which is the secondary battery with the smallest SOC or measured voltage of the multiple secondary batteries 2, reaches the over-discharge voltage.

[0046] By adopting this configuration, as shown in Figure 6, the voltage of the smallest secondary battery reaches the system shutdown voltage before it reaches the over-discharge voltage, thus stopping the power supply from the multiple secondary batteries 2 to the power supply destination system 4. Therefore, even if there is a malfunction in the opening function of the switch 3 connected to the secondary batteries 2, over-discharge of the secondary batteries 2 can be prevented. In addition, users of the power supply destination system 4 can recognize the over-discharge of the secondary batteries 2 when the power supply destination system 4 shuts down. The system charging voltage shown in the figure is set to a voltage that does not exceed the voltage upper limit of the power supply destination system 4 and secures the energy necessary for the operation of the power supply destination system 4. The opening circuit breaker voltage shown in the figure is the voltage for opening switch 3. When the total voltage of the multiple secondary batteries 2 falls below the opening circuit breaker voltage, the control device 10 sends an open signal to switch 3.

[0047] Figure 7 shows the change in voltage of a secondary battery over time when there is a malfunction in the circuit opening function and cell balancing is not performed. As shown in Figure 7, if cell balancing is not performed when there is a malfunction in the circuit opening function, the measured voltage of the secondary battery with the lowest measured voltage, in other words, the measured voltage of the secondary battery with the lowest SOC, will reach the over-discharge voltage before the total voltage of the multiple secondary batteries reaches the system shutdown voltage. On the other hand, in the embodiment described above, cell balancing is performed when there is a malfunction in the circuit opening function, so the multiple secondary batteries 2 will not enter an over-discharge state.

[0048] Furthermore, as described above, the cell balancing unit 106 continues to discharge the multiple secondary batteries 2 after performing the cell balancing process. Figure 8 shows the change in the total voltage of the multiple secondary batteries 2 over time when the cell balancing process is not performed in the case of an abnormality in the circuit opening function, and the change in the total voltage of the multiple secondary batteries 2 over time when the multiple secondary batteries 2 are continuously discharged after the cell balancing process is performed. As shown in Figure 8, by continuously discharging the multiple secondary batteries 2 after performing the cell balancing process, the total voltage reaches the system shutdown voltage more quickly.

[0049] Furthermore, as described above, if the variation determination unit 105 determines that there is no abnormality in the circuit opening function, it determines whether the difference between the maximum and minimum values ​​of the SOC or measured voltage of the multiple secondary batteries 2 is greater than or equal to a predetermined threshold. If it determines that the difference between the maximum and minimum values ​​of the SOC or measured voltage is greater than or equal to a predetermined threshold, the voltage determination unit 104 determines whether the measured voltage of each of the multiple secondary batteries 2 is greater than or equal to a second voltage threshold which is greater than the first voltage threshold. If it determines that the measured voltage of at least one of the multiple secondary batteries 2 is greater than or equal to the second voltage threshold, the cell balance processing unit 106 performs a cell balance process in which it charges the secondary batteries with the lower SOC or measured voltage among the multiple secondary batteries 2 using the secondary batteries with the higher SOC or measured voltage among the multiple secondary batteries 2.

[0050] By adopting this configuration, the secondary battery 2 with the lowest State of Charge (SOC) or measured voltage among the multiple secondary batteries 2 is charged, thereby preventing over-discharge of the secondary battery 2.

[0051] In the above example, the program can be stored and provided to the computer using various types of non-transitory computer-readable medium. Non-transitory computer-readable medium includes various types of tangible storage medium. Examples of non-transitory computer-readable medium include magnetic storage media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical storage media (e.g., magneto-optical disks), CD-ROMs, CD-Rs, CD-R / Ws, and semiconductor memory (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, RAMs). Alternatively, the program may be provided to the computer using various types of transient computer-readable medium. Examples of transient computer-readable medium include electrical signals, optical signals, and electromagnetic waves. Transitory computer-readable medium can supply the program to the computer via wired communication channels such as electric wires and optical fibers, or via wireless communication channels.

[0052] This disclosure is not limited to the embodiments described above, and may be modified as appropriate without departing from the spirit of this disclosure. [Explanation of Symbols]

[0053] 1: Battery control system 2: Secondary battery 2a: Secondary battery 2b: Secondary battery 3: Switch 4: Power supply destination system 5,6: Electric wires 10: Control device, battery control device 11: Cell balancing circuit 11a: Cell balancing circuit 11b: Cell balancing circuit 12: Voltage sensor 12a: Voltage sensor 12b: Voltage sensor 13: Voltage Sensor 100: Arithmetic device 101: Switch Control Unit 102: Measurement voltage acquisition unit 103: Open circuit function abnormality determination section 104: Voltage determination unit 105: Variation determination unit 106: Cell balance processing unit 110: Input / Output Port 120: Storage device

Claims

1. A circuit opening function abnormality determination unit that determines whether there is an abnormality in the circuit opening function of a switch connected to multiple secondary batteries connected in series, If it is determined that there is an abnormality in the circuit opening function, a voltage determination unit determines whether the measured voltage of each of the multiple secondary batteries is less than or equal to a first voltage threshold that is greater than the over-discharge voltage, which is the voltage corresponding to the over-discharge state of the secondary battery. Includes a cell balancing processing unit that performs cell balancing processing to adjust the SOC (State of Charge) or voltage of the plurality of secondary batteries so that the SOC or measured voltage of the plurality of secondary batteries is the same, When the cell balancing processing unit determines that the measured voltage of at least one of the plurality of secondary batteries is below the first voltage threshold, it performs the cell balancing process to set the total voltage, which is the sum of the measured voltages of the plurality of secondary batteries, to the shutdown voltage of the system powered by the plurality of secondary batteries, before the voltage of the minimum secondary battery, which is the secondary battery with the lowest SOC or measured voltage, reaches the over-discharge voltage. Battery control unit.

2. The battery control device according to claim 1, wherein the cell balancing processing unit determines that the measured voltage of at least one of the plurality of secondary batteries is less than or equal to the first voltage threshold, and performs a cell balancing process to discharge the secondary batteries other than the smallest secondary battery so that the SOC or measured voltage of the secondary batteries other than the smallest secondary battery approaches the SOC or measured voltage of the smallest secondary battery.

3. The battery control device according to claim 1, wherein the cell balancing processing unit determines that the measured voltage of at least one of the plurality of secondary batteries is less than or equal to the first voltage threshold, and performs a cell balancing process in which it charges the secondary battery with a lower SOC or measured voltage among the plurality of secondary batteries using the secondary battery with a higher SOC or measured voltage among the plurality of secondary batteries.

4. The battery control device according to any one of claims 1 to 3, wherein the cell balancing processing unit continues to discharge the plurality of secondary batteries after performing the cell balancing processing.

5. The battery control device according to any one of claims 1 to 3, wherein the shutdown voltage of the system is a voltage greater than the sum of the over-discharge voltages of the plurality of secondary batteries.

6. If it is determined that no abnormality has occurred in the circuit opening function, the system includes a variation determination unit that determines whether there is variation in SOC or measured voltage among the multiple secondary batteries by determining whether the difference between the maximum and minimum SOC values ​​of the multiple secondary batteries, or the difference between the maximum and minimum measured voltage values ​​of the multiple secondary batteries, is greater than or equal to a predetermined threshold. If it is determined that there is variation in SOC or measured voltage among the plurality of secondary batteries, the voltage determination unit determines whether the measured voltage of each of the plurality of secondary batteries is greater than or equal to a second voltage threshold which is greater than the first voltage threshold. The battery control device according to any one of claims 1 to 3, wherein, if it is determined that the measured voltage of at least one of the plurality of secondary batteries is equal to or greater than the second voltage threshold, the cell balancing processing unit performs a cell balancing process in which it charges the secondary battery with a lower SOC or measured voltage among the plurality of secondary batteries using the secondary battery with a higher SOC or measured voltage among the plurality of secondary batteries.

7. A control device for controlling multiple secondary batteries connected in series, This includes a cell balancing circuit connected to each of the aforementioned plurality of secondary batteries, The control device is A circuit opening function abnormality determination unit that determines whether there is an abnormality in the circuit opening function of the switches connected to the plurality of secondary batteries, If it is determined that there is an abnormality in the circuit opening function, a voltage determination unit determines whether the measured voltage of each of the multiple secondary batteries is less than or equal to a first voltage threshold that is greater than the over-discharge voltage, which is the voltage corresponding to the over-discharge state of the secondary battery. Includes a cell balancing processing unit that performs a cell balancing process to adjust the SOC or voltage of the plurality of secondary batteries so that the SOC or measured voltage of the plurality of secondary batteries is the same, When the cell balancing processing unit determines that the measured voltage of at least one of the plurality of secondary batteries is below the first voltage threshold, it causes the cell balancing circuit to perform the cell balancing process so that the total voltage, which is the sum of the measured voltages of the plurality of secondary batteries, becomes the shutdown voltage of the system powered by the plurality of secondary batteries, before the voltage of the minimum secondary battery, which is the secondary battery with the lowest SOC or measured voltage, reaches the over-discharge voltage. Battery control system.

8. A control method for controlling multiple secondary batteries connected in series, wherein a computer controls Determine if there is an abnormality in the opening function of the switch connected to multiple secondary batteries connected in series. If it is determined that there is an abnormality in the circuit opening function, it is determined whether the measured voltage of each of the multiple secondary batteries is below a first voltage threshold that is greater than the over-discharge voltage, which is the voltage corresponding to the over-discharge state of the secondary battery. If it is determined that the measured voltage of at least one of the plurality of secondary batteries is below the first voltage threshold, a cell balancing process is performed to adjust the SOC or voltage of the plurality of secondary batteries so that the SOC or measured voltage of the plurality of secondary batteries is the same, and the total voltage, which is the sum of the measured voltages of the plurality of secondary batteries, is set to the shutdown voltage of the system powered by the plurality of secondary batteries before the voltage of the smallest secondary battery, which is the secondary battery with the smallest SOC or measured voltage, reaches the over-discharge voltage. Control method.

9. A control program for controlling multiple secondary batteries connected in series, which allows a computer to: The system determines whether there is an abnormality in the opening function of the switch connected to multiple secondary batteries connected in series. If it is determined that there is an abnormality in the circuit opening function, the system will determine whether the measured voltage of each of the multiple secondary batteries is below a first voltage threshold that is greater than the over-discharge voltage, which is the voltage corresponding to the over-discharge state of the secondary battery. If it is determined that the measured voltage of at least one of the plurality of secondary batteries is below the first voltage threshold, a cell balancing process is performed to adjust the SOC or voltage of the plurality of secondary batteries so that the SOC or measured voltage of the plurality of secondary batteries is the same, and the total voltage, which is the sum of the measured voltages of the plurality of secondary batteries, is set to the shutdown voltage of the system supplied by the plurality of secondary batteries before the voltage of the smallest secondary battery, which is the secondary battery with the smallest SOC or measured voltage, reaches the over-discharge voltage. Control program.

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