JP3999580B2 - Charge / discharge control device and charge / discharge control method for battery pack - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to charge / discharge control of an assembled battery.
[0002]
[Prior art]
A technique for driving a load using an assembled battery including a plurality of rechargeable single cells (called cells) as a power source is known. The assembled battery repeatedly performs a discharging operation for driving the load and a charging operation for charging the cell. In such an assembled battery, the presence or absence of abnormality is determined by detecting the terminal voltages of the single cells constituting the assembled battery.
[0003]
[Problems to be solved by the invention]
The abnormality of a single cell includes an overcharge abnormality and an overdischarge abnormality. If it is determined that an abnormality has occurred in the cell, if both overcharge and overdischarge are not known, both charge control and discharge control must be stopped, and appropriate processing should be performed according to the content of the abnormality. I could not.
[0004]
The objective of this invention is providing the charging / discharging control apparatus and charging / discharging control method of an assembled battery which performed an appropriate process according to the abnormal content of overcharge and overdischarge.
[0005]
[Means for Solving the Problems]
The present invention relates to a charge / discharge control device that controls charging and discharging of an assembled battery composed of a plurality of single cells. When the detected voltage of each single cell is higher than a first voltage value, and for each detected single cell When the voltage of the battery is lower than the second voltage value lower than the first voltage value , respectively , and when detected during charging of the assembled battery, it is determined that the unit battery is overcharged, and when it is not charging If it is detected, the battery is determined to be overdischarged abnormally, and predetermined processing is performed according to the determination result.
[0006]
【The invention's effect】
According to the present invention, appropriate processing can be performed according to the determined abnormal contents of overcharge and overdischarge.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is an overall configuration diagram of a vehicle equipped with an assembled battery charge / discharge control device according to a first embodiment of the present invention. In the following embodiments, an example in which an assembled battery is applied as a power source of a hybrid electric vehicle will be described. In FIG. 1, an assembled battery 1 is configured by connecting n unit cells 11 to 1n in series. The charge / discharge control device includes current bypass circuits 21 to 2n, abnormality detection circuits 31 to 3n, an OR circuit 4, a charge / discharge control circuit 5, and an inverter / converter 6.
[0008]
The assembled battery 1 supplies current to the inverter / converter 6 during discharging. The inverter / converter 6 controls the output to the motor 7 according to a command from the charge / discharge control circuit 5. The motor 7 drives the wheel 10. When the inverter / converter 6 controls the output, the load current of the assembled battery 1 is controlled. The assembled battery 1 is charged with a current supplied from the inverter / converter 6 during charging. The inverter / converter 6 controls the charging current to the assembled battery 1 according to a command from the charge / discharge control circuit 5. The generator 8 is driven by the gasoline engine 9 and supplies the generated electric power to the inverter / converter 6.
[0009]
The charge / discharge control circuit 5 calculates a charge current value and a discharge current (load current) value for the assembled battery 1 using voltage data of the assembled battery 1 detected by a voltage detection circuit (not shown), and these charge current and discharge A charge control value and a discharge control value for obtaining a current are output to the inverter / converter 6. The actual control value while the vehicle is running is calculated using detection values obtained by various sensors (not shown) such as an accelerator operation amount sensor and a brake operation amount sensor in addition to the voltage data.
[0010]
In the cells 11 to 1n, current bypass circuits 21 to 2n are provided in parallel to the respective cells. The current bypass circuits 21 to 2n detect the terminal voltages of the cells connected in parallel, respectively, and when the detection voltage at the time of charging the assembled battery 1 reaches a first determination threshold value lower than the charge end voltage by a predetermined value, The charging current of the cell is bypassed to the current bypass circuit. As a result, the charging current to the unit cell is reduced, and the rate at which the unit cell is fully charged, that is, the state where the depth of discharge (DOD) is 0%, is slowed down. The end-of-charge voltage is a terminal voltage corresponding to DOD 0% of the unit cell.
[0011]
The unit cells 11 to 1n are further provided with abnormality detection circuits 31 to 3n in parallel to the unit cells. The abnormality detection circuits 31 to 3n detect the terminal voltages of the cells connected in parallel, respectively, and the detection voltage at the time of charging and discharging of the assembled battery 1 is set to a second determination threshold that is lower than the charge end voltage by a predetermined value. When the detection voltage reaches the third determination threshold that is higher than the discharge end voltage by a predetermined value, an abnormality detection signal is output to the OR circuit 4, respectively. The end-of-discharge voltage is a terminal voltage corresponding to a state in which the unit cell is fully discharged, that is, DOD 100%. The determination threshold has a relationship of second determination threshold> first determination threshold> third determination threshold.
[0012]
The OR circuit 4 calculates the logical sum of the abnormality detection signals output from the abnormality detection circuits 31 to 3n and outputs the calculation result to the charge / discharge control circuit 5. Thereby, when an abnormality is detected in any of the abnormality detection circuits 31 to 3n, the charge / discharge control circuit 5 is notified of the abnormality.
[0013]
In the present invention, when an abnormality is detected in any of the abnormality detection circuits 31 to 3n constituting the charge / discharge control device, the abnormality content is determined, and different processing is performed according to the determination content.
[0014]
In the above description, each of the current bypass circuits 21 to 2n and the abnormality detection circuits 31 to 3n detects the voltage of the unit cell, but includes one set of voltage detection circuits that detect the terminal voltage of each unit cell. You may comprise so that the detected value by a voltage detection circuit may be used together by the current bypass circuits 21-2n and the abnormality detection circuits 31-3n. For example, the abnormality detection circuits 31 to 3n are provided with a voltage detection circuit for a single battery, and the abnormality detection circuits 31 to 3n themselves and the current bypass circuits 21 to 2n use the voltage detection values of the abnormality detection circuits 31 to 3n.
[0015]
FIG. 2 is a flowchart for explaining the flow of the charge / discharge control process of the assembled battery 1 performed by the charge / discharge control circuit 5. The processing according to FIG. 2 is repeatedly performed when a power switch (not shown) of the charge / discharge control device is turned on. In step S1 of FIG. 2, the charge / discharge control circuit 5 determines whether or not there is a cell abnormality. The charge / discharge control circuit 5 makes an affirmative determination in step S1 when an abnormality is notified from the OR circuit 4, and proceeds to step S2. If the abnormality is not notified from the OR circuit 4, the charge / discharge control circuit 5 makes a negative determination in step S1. The process according to FIG. 2 ends.
[0016]
In step S <b> 2, the charge / discharge control circuit 5 determines whether or not the battery pack 1 is being charged. When the battery pack 1 is being charged, the charge / discharge control circuit 5 makes an affirmative decision in step S2 and proceeds to step S3. If not charged, the charge / discharge control circuit 5 makes a negative decision in step S2 and proceeds to step S4. In step S3, the charge / discharge control circuit 5 determines that the abnormality detection signal is an overcharge abnormality, and proceeds to step S5. An overcharge abnormality is a case where the terminal voltage of any one of the cells 11 to 1n is equal to or higher than the second determination threshold value. In step S5, the charge / discharge control circuit 5 performs a predetermined abnormality avoidance process based on the overcharge abnormality, and ends the process of FIG. The abnormality avoidance process in this case may be a control process in a direction that suppresses the charge amount that restricts the charge current or prohibits the charge.
[0017]
When the process proceeds to step S4, when the battery pack 1 is being controlled to be discharged (during discharging), when the power switch of the charge / discharge control device is turned on (starting), and neither the battery pack 1 is charged nor discharged. Including time. In step S4, the charge / discharge control circuit 5 determines that the abnormality detection signal is an overdischarge abnormality, and proceeds to step S6. The overdischarge abnormality is when the terminal voltage of any one of the cells 11 to 1n is equal to or lower than the third determination threshold value. In step S6, the charge / discharge control circuit 5 performs a predetermined abnormality avoidance process based on the overdischarge abnormality, and ends the process of FIG. The abnormality avoidance process in this case may be a control process in a direction that suppresses the discharge amount that restricts the discharge current or prohibits the discharge.
[0018]
The first embodiment described above will be summarized.
(1) The charge / discharge control device includes current bypass circuits 21 to 2n, and the terminal voltage of any one of the cells 11 to 1n reaches a first determination threshold that is lower than the charge end voltage by a predetermined value during charging of the assembled battery 1. Then, the charging current of the unit cell is bypassed. Accordingly, since the charging current of a single cell that has approached full charge (DOD 0%) sooner than other single cells decreases and the speed at which the single cell reaches the full charge state becomes slow, The difference in DOD between the batteries can be reduced, and variations in DOD between single cells can be suppressed. As a result, a reduction in discharge capacity as the assembled battery 1 can be prevented. The variation in DOD is caused by a difference in characteristics between the single cells produced during the production of the single cells, a difference in temperature environment between the single cells in use as the assembled battery 1, and the like.
[0019]
(2) The charge / discharge control device includes abnormality detection circuits 31 to 3n, and a second determination threshold value at which the terminal voltage of any of the cells 11 to 1n is lower than the charge end voltage by a predetermined value when the assembled battery 1 is charged and discharged. Or when the third determination threshold value higher than the discharge end voltage by a predetermined value is reached, an abnormality detection signal is output. Therefore, it can be detected that any single cell is approaching full charge or approaching full discharge (DOD 0%). Note that the determination threshold value is second determination threshold value> first determination threshold value> third determination threshold value.
[0020]
(3) When the abnormality detection circuits 31 to 3n detect an abnormality, the charge / discharge control circuit 5 separates the overcharge abnormality and the overdischarge abnormality depending on whether or not the battery pack 1 is being charged. It is possible to take measures according to the abnormal content.
[0021]
(Second embodiment)
Instead of the process of FIG. 2, the charge / discharge control process of FIG. 3 may be performed. Here, the same steps as those in FIG. 2 are denoted by the same step numbers as those in FIG. In step S11 that proceeds after making an affirmative determination in step S2 of FIG. 3, the charge / discharge control circuit 5 switches from charge control to discharge control and proceeds to step S12. In step S12, the charge / discharge control circuit 5 determines whether or not the cell abnormality continues. The charge / discharge control circuit 5 makes an affirmative determination in step S12 when the abnormality notification is continued from the OR circuit 4, and proceeds to step S15. If the abnormality notification is not continued from the OR circuit 4, the negative determination is made in step S12. Then, the process proceeds to step S16.
[0022]
In step S15, the charge / discharge control circuit 5 determines that the abnormality detection signal is an overdischarge abnormality, and proceeds to step S6. In step S6, the charge / discharge control circuit 5 performs a predetermined abnormality avoidance process based on the overdischarge abnormality, and ends the process of FIG.
[0023]
In step S13, which proceeds with a negative determination in step S2, the charge / discharge control circuit 5 switches to charge control (starts charging) and proceeds to step S14. In step S14, the charge / discharge control circuit 5 determines whether or not the cell abnormality continues. The charge / discharge control circuit 5 makes an affirmative determination in step S14 when abnormality notification is continued from the OR circuit 4, and proceeds to step S16. If the abnormality notification is not continued from the OR circuit 4, the negative determination is made in step S14. Then, the process proceeds to step S15.
[0024]
In step S16, the charge / discharge control circuit 5 determines that the abnormality detection signal indicates an overcharge abnormality, and proceeds to step S5. In step S5, the charge / discharge control circuit 5 performs a predetermined abnormality avoidance process based on the overcharge abnormality, and ends the process of FIG.
[0025]
According to the second embodiment described above, the overcharge abnormality and the overdischarge abnormality are separated depending on whether the abnormality continues even when the charge / discharge control is switched. In the same manner as described above, it is possible to perform treatment according to the abnormality.
[0026]
(Third embodiment)
Instead of the process of FIG. 2, the charge / discharge control process of FIG. 4 may be performed. Here, the same steps as those in FIG. 2 are denoted by the same step numbers as those in FIG. In step S21 of FIG. 4, the charge / discharge control circuit 5 outputs a command for reducing the charge amount to the inverter / converter 6 and proceeds to step S22. As a result, the inverter / converter 6 reduces the charging current. In step S22, the charge / discharge control circuit 5 determines whether or not the cell abnormality continues. The charge / discharge control circuit 5 makes an affirmative decision in step S22 when the abnormality notification is continued from the OR circuit 4, and proceeds to step S23. If the abnormality notification is not continued from the OR circuit 4, the negative determination is made in step S22. Then, the process according to FIG. In step S23, the charge / discharge control circuit 5 outputs a command for prohibiting charging to the inverter / converter 6 and ends the process of FIG. As a result, the inverter / converter 6 stops charging the battery pack 1 (sets the charging current to 0).
[0027]
In step S24 of FIG. 4, the charge / discharge control circuit 5 outputs a command for reducing the discharge amount to the inverter / converter 6 and proceeds to step S25. As a result, the inverter / converter 6 reduces the load current. In step S25, the charge / discharge control circuit 5 determines whether or not the cell abnormality continues. The charge / discharge control circuit 5 makes an affirmative decision in step S25 when the abnormality notification is continued from the OR circuit 4, and proceeds to step S26. If the abnormality notification is not continued from the OR circuit 4, the negative determination is made in step S25. Then, the process according to FIG. In step S <b> 26, the charge / discharge control circuit 5 outputs a command for prohibiting discharge to the inverter / converter 6, and ends the process of FIG. 4. As a result, the inverter / converter 6 stops discharging the assembled battery 1 (the load current is set to 0).
[0028]
According to the third embodiment described above, overcharge abnormality and overdischarge abnormality are separated depending on whether charging control of the assembled battery 1 is being performed, the amount of charge is reduced in the case of overcharge abnormality, and the case of overdischarge The amount of discharge was narrowed down, and charging was prohibited or discharge was prohibited depending on whether the abnormality continued thereafter. As a result, appropriate measures can be taken according to the abnormality.
[0029]
(Fourth embodiment)
In the fourth embodiment, when it is determined that there is an overcharge abnormality or an overdischarge abnormality, charging or discharging is prohibited according to the total voltage of the assembled battery 1. FIG. 5 is an overall configuration diagram of a vehicle equipped with an assembled battery charge / discharge control device according to a fourth embodiment of the present invention. 5, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. The total voltage detection circuit 50 is configured to detect the total voltage of the assembled battery 1 and output a detection signal to the charge / discharge control circuit 5A. The total voltage is a terminal voltage of the assembled battery 1.
[0030]
FIG. 6 is a flowchart for explaining the flow of the charge / discharge control process according to the fourth embodiment. Here, the same steps as those in FIG. 4 are denoted by the same step numbers as those in FIG. In step S31 of FIG. 6, the charge / discharge control circuit 5A determines whether or not the total voltage is equal to or higher than the fourth determination threshold value V4. The determination threshold V4 is a voltage value that is lower than the charge end total voltage by a predetermined value. The charge / discharge control circuit 5A makes an affirmative decision in step S31 when the voltage value based on the detection signal sent from the total voltage detection circuit 50 is equal to or greater than the fourth determination threshold value V4, proceeds to step S32, and the voltage value is the fourth value. If it is less than the determination threshold value V4, a negative determination is made in step S31, and the processing in FIG.
[0031]
In step S32, the charge / discharge control circuit 5A outputs a command for prohibiting charging to the inverter / converter 6 and ends the process of FIG. As a result, the inverter / converter 6 stops charging the battery pack 1.
[0032]
In step S33, the charge / discharge control circuit 5A determines whether or not the total voltage is equal to or lower than the fifth determination threshold value V5. The determination threshold V5 is a voltage value that is higher than the discharge end total voltage by a predetermined value. The charge / discharge control circuit 5A makes an affirmative decision in step S33 when the voltage value based on the detection signal sent from the total voltage detection circuit 50 is equal to or lower than the fifth determination threshold value V5, and proceeds to step S34. If the determination threshold value V5 is exceeded, a negative determination is made in step S33 and the processing in FIG. 6 is terminated.
[0033]
In step S34, the charge / discharge control circuit 5A outputs a command for prohibiting the discharge to the inverter / converter 6 and ends the process of FIG. As a result, the inverter / converter 6 stops discharging the assembled battery 1.
[0034]
According to the fourth embodiment described above, overcharge abnormality and overdischarge abnormality are separated depending on whether charging control of the assembled battery 1 is being performed, and after the separation, the total voltage is detected, and overcharge abnormality and total voltage are detected. Charging is prohibited when the value is equal to or higher than the fourth determination threshold value, and discharging is prohibited when overdischarge is abnormal and the total voltage is equal to or lower than the fifth determination threshold value. As a result, appropriate measures can be taken according to the abnormality.
[0035]
(Fifth embodiment)
In the fifth embodiment, the amount of charge or the amount of discharge is reduced in accordance with the contents of cell abnormality determined in the past, that is, overdischarge abnormality or overcharge abnormality. FIG. 7 is a flowchart for explaining the flow of the charge / discharge control process according to the fifth embodiment. The process according to FIG. 7 is performed before step S1 in each charge / discharge control process according to the first to fourth embodiments described above.
[0036]
In step S41 of FIG. 7, the charge / discharge control circuit 5 (5A) determines whether or not there is a cell abnormality experience in the past. The charge / discharge control circuit 5 (5A) makes an affirmative decision in step S41 when there is an experience of determining a cell abnormality and proceeds to step S42, and makes a negative determination of step S41 if there is no experience of determining a cell abnormality. 7 is terminated. When the process of FIG. 7 is terminated, the process proceeds to step S2 of each charge / discharge control process described above.
[0037]
In step S42, the charge / discharge control circuit 5 (5A) determines a past abnormal mode. The charge / discharge control circuit 5 (5A) proceeds to step S43 when it is determined that the overcharge abnormality has occurred in the past, and proceeds to step S44 when it is determined that the overdischarge abnormality has occurred in the past. In step S43, the charge / discharge control circuit 5 (5A) ends the process of FIG. 7 so as to reduce the amount of charge during charge control of the assembled battery 1. In step S44, the charge / discharge control circuit 5 (5A) ends the process of FIG. 7 so as to reduce the discharge amount during the discharge control of the assembled battery 1.
[0038]
According to the fifth embodiment described above, the amount of charge at the time of charge control is narrowed down when there is experience in determining overcharge abnormality in the past, and the amount of discharge at the time of discharge control when there is experience of determining overdischarge abnormality. Since each charge / discharge control process according to any one of the first embodiment to the fourth embodiment is performed after narrowing down, it is appropriate to cope with an abnormality that has occurred in the past and an abnormality that has newly occurred. Can be treated.
[0039]
The correspondence between each component in the claims and each component in the embodiment of the invention will be described. An assembled battery is comprised by the cell 11-11n, for example. The charge / discharge control means, the charge determination means, the determination means, and the abnormality processing means are configured by, for example, the charge / discharge control circuit 5 (5A). The voltage detection means and the abnormality detection means are constituted by, for example, abnormality detection circuits 31 to 3n. The first voltage value corresponds to, for example, a second determination threshold value. The second voltage value corresponds to, for example, a third determination threshold value. For example, the fourth determination threshold corresponds to the first total voltage value. The second total voltage value corresponds to, for example, a fifth determination threshold value. In addition, each component is not limited to the said structure, unless the characteristic function of this invention is impaired.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a vehicle equipped with an assembled battery charge / discharge control device according to a first embodiment of the present invention;
FIG. 2 is a flowchart for explaining a flow of an assembled battery charge / discharge control process performed by a charge / discharge control circuit;
FIG. 3 is a flowchart for explaining a flow of charge / discharge control processing of a battery pack according to the second embodiment.
FIG. 4 is a flowchart for explaining a flow of charge / discharge control processing for an assembled battery according to a third embodiment;
FIG. 5 is an overall configuration diagram of a vehicle equipped with an assembled battery charge / discharge control device according to a fourth embodiment of the present invention;
FIG. 6 is a flowchart for explaining a flow of charge / discharge control processing for an assembled battery according to a fourth embodiment;
FIG. 7 is a flowchart for explaining a flow of charge / discharge control processing for an assembled battery according to a fifth embodiment;
[Explanation of symbols]
1 ... assembled battery, 4 ... OR circuit,
5, 5A ... charge / discharge control circuit, 6 ... inverter / converter,
11 to 1n, single cell, 21 to 2n, current bypass circuit,
31 to 3n: Abnormality detection circuit 50: Total voltage detection circuit

Claims (10)

Charging / discharging control means for controlling charging and discharging of a battery pack composed of a plurality of single cells;
A voltage detecting means provided for each unit cell for detecting the voltage of each unit cell;
Charge determining means for determining whether or not the assembled battery is being charged;
Provided for each unit cell, when the voltage detected by the voltage detection means is higher than the first voltage value, and when the voltage detected by the voltage detection means is lower than the second voltage value lower than the first voltage value Anomaly detection means for outputting a signal indicating anomaly when low,
When the signal indicating the abnormality is output when the charging determination unit determines that charging is in progress, it is determined that the unit cell is overcharged abnormally, and when the charging determination unit does not determine that charging is in progress, the abnormality is determined. Determining means for determining that the unit cell is overdischarged when a signal indicating is output;
An assembled battery charge / discharge control apparatus comprising: an abnormality processing unit that instructs the charge / discharge control unit to perform a predetermined process according to a determination result of the determination unit. In the assembled battery charge / discharge control device according to claim 1,
The time when the charge determination means does not determine that the battery is being charged is when the charge / discharge control device is started, when the battery pack is discharged, and when the battery pack is neither charged nor discharged A charge / discharge control device for an assembled battery, comprising: In the charging / discharging control apparatus of the assembled battery according to claim 1 or 2,
The determination unit instructs the charge / discharge control unit to switch from charge to discharge when the signal indicating the abnormality is output when the charge determination unit determines that charging is in progress, and instructs to switch to the discharge. When the signal indicating the abnormality is continuously output later, it is determined that the battery is overdischarged abnormally, and when the signal indicating the abnormality is not output after the switching instruction to the discharge is performed, the battery is overcharged abnormally And a charge / discharge control device for an assembled battery. In the charging / discharging control apparatus of the assembled battery in any one of Claims 1-3,
The determination means instructs the charge / discharge control means to start charging when a signal indicating the abnormality is output when the charge determination means does not determine that charging is in progress, and instructs to switch to the charge When the signal indicating the abnormality is continuously output later, it is determined that the unit battery is overcharged abnormally. And a charge / discharge control device for an assembled battery. In the charging / discharging control apparatus of the assembled battery in any one of Claims 1-4,
The abnormality processing means instructs the charge / discharge control means to reduce the amount of charge when an overcharge abnormality of the unit cell is determined by the determination means, and continuously outputs a signal indicating the abnormality after the instruction. When this is done, the charge / discharge control device for a battery pack further instructs the charge / discharge control means to prohibit charging. In the charging / discharging control apparatus of the assembled battery in any one of Claims 1-5,
The abnormality processing means instructs the charge / discharge control means to reduce the discharge amount when the determination means determines that the overdischarge abnormality of the unit cell, and continuously outputs a signal indicating the abnormality after the instruction. When this is done, the charge / discharge control device for a battery pack further instructs the charge / discharge control means to prohibit discharge. In the charging / discharging control apparatus of the assembled battery as described in any one of Claims 1-4,
Further comprising total voltage detecting means for detecting the voltage of the assembled battery;
The abnormality processing means prohibits the charge / discharge control means from being charged when the determination means determines that the overcharge abnormality of the unit cell is detected and the voltage detected by the total voltage detection means is higher than a predetermined total voltage value. A charge / discharge control device for an assembled battery, characterized by: In the charging / discharging control apparatus of the assembled battery as described in any one of Claims 1-4 ,
Further comprising total voltage detecting means for detecting the voltage of the assembled battery;
The abnormality processing means prohibits the charge / discharge control means from discharging when the determination means determines that an overdischarge abnormality of the unit cell is detected and the voltage detected by the total voltage detection means is lower than a predetermined total voltage value. A charge / discharge control device for an assembled battery, characterized by: In the charging / discharging control apparatus of the assembled battery in any one of Claims 1-8,
The abnormality processing means instructs the charge / discharge control means to reduce the charge amount regardless of the presence or absence of a signal indicating the abnormality after the determination means determines that the overcharge abnormality of the unit cell is present, and the determination Charge / discharge control of the assembled battery, characterized in that the charge / discharge control means is instructed to reduce the discharge amount regardless of the presence or absence of a signal indicating the abnormality after the unit determines that the overdischarge abnormality of the unit cell is detected. apparatus. In a charge / discharge control method for controlling charge and discharge of a battery pack composed of a plurality of single cells,
Detecting the voltage of each unit cell,
Determine whether the battery pack is charging,
When the detected voltage of the single cell is higher than a first voltage value, and when the detected voltage of the single cell is lower than a second voltage value lower than the first voltage value, respectively,
When it is determined that the battery is being charged, it is determined that the battery is overcharged when it is considered abnormal, and when it is not determined that the battery is being charged, the battery is overdischarged. Judged as abnormal,
A charge / discharge control method for an assembled battery, wherein a predetermined process is instructed according to the determination result.

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