KR102362208B1 - Abnormal cell detection device, battery system and abnormal cell detection method thereof - Google Patents

Abstract

An apparatus for detecting abnormal cells of a battery module including a plurality of cells according to an embodiment includes a measurement unit measuring cell voltage values of the plurality of cells while changing a measurement time, and a predetermined time period based on the cell voltage values Calculates the voltage change amount and the voltage change amount deviation of each of the plurality of cells for It may include a detection unit.

Description

Abnormal cell detection device, battery system, and abnormal cell detection method of a battery system

An embodiment of the present invention relates to an abnormal cell detection apparatus, a battery system, and a method for detecting an abnormal cell in the battery system.

A secondary battery differs from a primary battery in that it provides only irreversible conversion of chemical substances into electrical energy in that charging and discharging can be repeated. A low-capacity rechargeable battery is used as a power supply for small electronic devices such as cellular phones, notebook computers, and camcorders, and a high-capacity rechargeable battery is used as a power supply for a hybrid vehicle or the like.

In general, a secondary battery includes an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, a case accommodating the electrode assembly, and an electrode terminal electrically connected to the electrode assembly. In order to enable charging and discharging of the battery through the electrochemical reaction of the positive electrode, the negative electrode, and the electrolyte solution, the electrolyte is injected into the case. The shape of the case, such as cylindrical or rectangular, depends on the use of the battery.

An internal short circuit in which the positive and negative poles inside the secondary battery are short-circuited is one of the causes of overheating the secondary battery and causing safety problems in the battery system such as thermal runaway and fire. Accordingly, various technologies have been developed to prevent safety problems such as thermal runaway by detecting the occurrence of an internal short circuit of a secondary battery. However, in the current internal short-circuit detection system, it is difficult to detect an internal short or a minute internal short that occurs while the battery system is left unattended.

An object to be solved through embodiments of the present invention is to provide an apparatus for detecting an abnormal cell capable of detecting an internal short or a minute internal short that occurs while a battery system is left unattended, a battery system, and a method for detecting an abnormal cell in the battery system .

An apparatus for detecting abnormal cells of a battery module including a plurality of cells according to an embodiment of the present invention for solving the above problems includes a measuring unit measuring cell voltage values of the plurality of cells while changing a measurement time, and the cell Calculate the voltage change amount and the voltage change amount deviation of each of the plurality of cells for a predetermined time period based on the voltage values, and based on the voltage change amount deviation calculated for each of the plurality of cells while changing the time period A detection unit for detecting an abnormal cell among the plurality of cells may be included.

The detector may detect a cell in which the absolute value of the voltage variation deviation in the same time period is the maximum or is equal to or greater than a predetermined value as an abnormal cell.

The detection unit registers at least one cell selected in the order of the highest absolute value of the voltage variation deviation in each time interval as an abnormal cell candidate group, and detects the cell registered as the abnormal cell candidate group in one or more time intervals as an abnormal cell. may be

The detection unit may calculate a voltage change rate deviation from the voltage change amount deviation in each time interval, and detect a cell having an absolute value of the voltage change rate deviation equal to or greater than a predetermined value as an abnormal cell.

The detection unit calculates a voltage change rate deviation from the voltage change amount deviation in each time period, and registers at least one cell selected in the order of the absolute value of the voltage change rate deviation in each time period as an abnormal cell candidate group, one In the above time period, a cell registered as the abnormal cell candidate group may be detected as an abnormal cell.

The detector may calculate the voltage change amount and the voltage change amount deviation by using cell voltage values measured in a state in which the battery module is idle among the cell voltage values measured by the measuring unit.

In addition, the battery system according to an embodiment of the present invention may include a battery module including a plurality of cells and the abnormal cell detection device.

In addition, the method for detecting abnormal cells in a battery system including a plurality of cells according to an embodiment of the present invention includes measuring cell voltage values of the plurality of cells while changing a measurement time, changing a time period, Calculating a voltage change amount and a voltage change amount deviation of each of the plurality of cells from cell voltage values, and detecting an abnormal cell among the plurality of cells based on the voltage change amount deviation in each time interval. have.

The detecting may include detecting a cell in which the absolute value of the voltage variation deviation in the same time period is the maximum or is greater than or equal to a predetermined value as an abnormal cell.

The detecting may include registering at least one cell selected in the order of the highest absolute value of the voltage variation deviation in each time interval as an abnormal cell candidate group, and cells registered as the abnormal cell candidate group in one or more time intervals It may include the step of detecting as an abnormal cell.

The detecting may include calculating a voltage change rate deviation from the voltage change amount deviation in each time interval, and detecting a cell having an absolute value of the voltage change rate deviation equal to or greater than a predetermined value as an abnormal cell.

The detecting may include calculating a voltage change rate deviation from the voltage change amount deviation in each time period, and registering at least one cell selected in the order of the highest absolute value of the voltage change rate deviation in each time period as an abnormal cell candidate group and detecting a cell registered as the abnormal cell candidate group as an abnormal cell in one or more time intervals.

The calculating may include calculating the voltage change amount and the voltage change amount deviation by using cell voltage values measured in a state in which the battery system is in a rest state among the cell voltage values.

According to embodiments of the present invention, it is possible to detect the occurrence of an internal short circuit of a cell even while the battery system is left unattended. In addition, it is possible to avoid a situation in which instantaneous voltage fluctuations due to noise are mistakenly recognized as internal short circuits, and it is possible to detect the occurrence of minute internal short circuits in which the voltage change is relatively insignificant.

1 schematically illustrates a battery system according to an embodiment of the present invention.
FIG. 2 illustrates an example of the battery module of FIG. 1 .
3 is an equivalent circuit of secondary battery cells constituting the battery module of FIG. 2 .
4 schematically illustrates a method for detecting an abnormal cell in a battery system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, with reference to the accompanying drawings, the effects and features of the embodiments and their implementation methods will be described in detail. In the drawings, like reference numerals denote like elements, and overlapping descriptions thereof are omitted. However, the present invention may be implemented in various forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the aspects and features of the invention to those skilled in the art.

Accordingly, processes, elements, and techniques deemed not necessary to those skilled in the art for a thorough understanding of aspects and features of the present invention may not be described. In the drawings, the relative sizes of elements, layers, and regions may be exaggerated for clarity.

The term "and/or" in this document includes any combination or any combination of a plurality of related listed items. The use of “may” when describing embodiments of the present invention means “one or more embodiments of the present invention”. In the following description of embodiments of the present invention, terms in the singular form may include the plural form unless the context clearly dictates otherwise.

The terms “first” and “second” are used to describe various elements, but these elements are not limited by these terms. These terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as the first component, and similarly, the first component may also be referred to as the second component.

Hereinafter, an apparatus for detecting an abnormal cell, a battery system, and a method for detecting an abnormal cell of the battery system according to an embodiment of the present invention will be described in detail with reference to the necessary drawings.

1 schematically shows a battery system according to an embodiment of the present invention, and FIG. 2 shows an example of the battery module of FIG. 1 .

Referring to FIG. 1 , a battery system 1 according to an embodiment of the present invention may include a battery module 10 and an abnormal cell detection device 20 .

The battery module 10 may include at least one secondary battery cell (hereinafter, referred to as a 'cell') connected in series and/or in parallel.

Taking FIG. 2 as an example, the battery module 10 includes a plurality of battery sub-modules 11 connected to each other in parallel between two system terminals T+ and T-. In addition, each battery submodule 11 includes a plurality of cell banks 13 connected in series with each other, and each cell bank 13 includes a plurality of cells connected in parallel with each other, for example, two cells. (100). 2 illustrates an example of the battery module 10 , the configuration of the battery module 10 is not limited thereto. For example, the battery module 10 may be configured as a single cell. Also, for example, the battery module 10 may consist of only a plurality of cells connected in series to each other. Also, for example, the battery module 10 may be configured by connecting a plurality of battery sub-modules each composed of a plurality of cells connected in series to each other in parallel. Also, for example, the battery module 10 may be configured by connecting a plurality of battery sub-modules each configured with a plurality of cells connected in series and/or in parallel to each other in series.

The battery module 10 is connected to an external charging device (not shown) or a load through the system terminals T+ and T−, and may be charged by the charging device or discharged by the load.

3 is an equivalent circuit of secondary battery cells constituting the battery module of FIG. 2 .

Referring to FIG. 3 , each cell 100 constituting the battery module 10 may include an internal resistance R _B , and the internal resistance R _B has a resistance value of several mΩ to several hundreds of mΩ. can When an internal short circuit occurs in the cell 100 , the same effect as when the switch S inside the cell 100 conducts occurs. When the switch _S conducts due to the occurrence of an internal short circuit of the cell 100 , a short circuit current I _short flows through the short circuit resistor RS and the cell 100 is discharged. In this case, the short-circuit resistance RS may have a resistance value in a wide range from several _mΩ to several kΩ.

Again, referring to FIG. 1 , the abnormal cell detection apparatus 20 according to an embodiment of the present invention detects an internal short circuit of the battery module 10 and protects the battery module 10 from a dangerous situation due to the internal short circuit. protection function can be implemented. To this end, the abnormal cell detection apparatus 20 may include a measurement unit 21 , a detection unit 22 , a control unit 23 , and a memory 24 .

The measuring unit 21 continuously measures the voltage of the cells 100 constituting the battery module 10 while changing the measurement timing constituting the battery module 10, and the measured voltage value (hereinafter, 'cell voltage value') ) may be transferred to the detection unit 22 . The measurement unit 21 may perform measurement discretely. A predetermined time interval may exist between the two measurement points, and the length of the time interval may be the same or may be changed. In the latter case, the time interval between measurement time points may be changed depending on the state of the battery module 10 (charging, discharging, and idle state), how much time has elapsed from the charging/discharging end time, and the like.

The detection unit 22 may receive the cell voltage values of the battery module 10 measured by the measurement unit 21 . Then, based on the received cell voltage values, the voltage change amount of each of the plurality of cells 100 may be calculated for a predetermined time period. That is, the detector 22 may calculate a voltage change amount in a corresponding time period by calculating a difference between cell voltage values measured at two different measurement time points for each cell 100 . Here, the detector 22 may calculate the voltage change amount by using only voltage values measured in a rest period in which the battery module 10 is in a rest state among the received cell voltage values. The idle state of the battery module 10 means a state in which the battery module 10 is charging or not discharging, that is, a state in which the battery module 10 is not electrically connected to a charger or a load. The detector 22 may recognize whether the battery module 10 is in the idle state by monitoring the cell voltage values of the battery module 10 or the charge/discharge current value of the battery module 10 .

As described above, when the voltage change amount is calculated for each cell 100 in a predetermined time period, the detector 22 may calculate a voltage change amount deviation for each cell 100 in the corresponding time period. Here, the voltage variation deviation means a difference value between the average value of the voltage variations of all cells 100 constituting the battery module 10 and the voltage variation of each cell 100 .

The detection unit 22 calculates the voltage change amount and the voltage change amount deviation of each cell 100 in the above-described manner while changing the time period, and compares the calculated voltage change amount and the voltage change amount deviation with the cell voltage value of each cell 100 They may be stored together in the memory 24 . In this case, the length of each time interval may be the same or different from each other.

In addition, the detector 22 monitors the voltage variation calculated for each cell 100 in each time interval, and among the cells 100 constituting the battery module 10 , an abnormal cell (eg, a cell in which an internal short circuit has occurred) ) can be detected.

For example, the detection unit 22 detects a cell in which the absolute value (hereinafter, referred to as 'absolute deviation') of the voltage change amount deviation in the same time interval among the plurality of cells 100 is greater than or equal to a predetermined value or greater than the maximum cell. cells can be detected.

Also, for example, the detection unit 22 registers at least one cell 100 selected in the order of the highest absolute deviation of the voltage change in each time interval as an abnormal cell candidate group, and is registered as an abnormal cell candidate group in one or more time intervals. The cell 100 may be detected as an abnormal cell.

In addition, for example, the detection unit 22 calculates the voltage change rate deviation by dividing each voltage change amount deviation by the time length of the corresponding time period as in Equation 1 below, and the voltage change rate deviation is a cell having a predetermined value or more. may be detected as an abnormal cell.

[Equation 1]

((B - A) - average(∑B-A)) / t

In Equation 1 above, for the same cell, A and B represent cell voltage values measured at different measurement time points, average(∑BA) represents the average voltage change amount of all cells, and t represents the time of the corresponding time interval. indicates the length.

Also, for example, the detection unit 22 registers at least one cell 100 selected in the order of the highest absolute deviation of the voltage change rate in each time interval as an abnormal cell candidate group, and is registered as an abnormal cell candidate group in one or more time intervals. The cell 100 may be detected as an abnormal cell.

As described above, when an abnormal cell or an abnormal cell candidate group is detected, the detection unit 22 sets a flag indicating that the corresponding cells are the abnormal cell or the abnormal cell candidate group, and registers the abnormal cell or the abnormal cell candidate group in the memory 24 can do.

Table 1 below shows an example of a cell voltage change when an abnormal cell occurs.

cell after balancing After discharge (A) After leaving (B) voltage change
Deviation
(average: 0.019) After leaving (C) voltage variation deviation
(average: 0.000) Voltage
(V) Voltage
(V) Voltage
(V) Voltage
Change (BA) Voltage
(V) Voltage
Change (CB) #One 3.560 3.187 3.212 0.025 0.006 3.212 0.000 0.000 #2 3.558 3.181 3.204 0.023 0.004 3.204 0.000 0.000 #3 3.559 3.203 3.224 0.022 0.002 3.224 0.000 0.000 #4 3.561 3.212 3.228 0.017 -0.003 3.228 0.000 0.000 #5 3.560 3.181 3.206 0.026 0.006 3.206 0.000 0.000 #6 3.560 3.202 3.222 0.020 0.001 3.222 0.000 0.000 #7 3.567 3.349 3.328 -0.021 -0.040 3.323 -0.005 -0.005 #8 3.560 3.186 3.204 0.018 -0.001 3.203 -0.001 -0.001 #9 3.561 3.198 3.217 0.019 0.000 3.217 0.000 0.000 #10 3.559 3.183 3.201 0.018 -0.001 3.200 -0.001 -0.001 #11 3.562 3.192 3.218 0.027 0.007 3.218 0.000 0.000 #12 3.561 3.209 3.227 0.018 -0.001 3.226 -0.001 -0.001 #13 3.560 3.186 3.210 0.024 0.005 3.210 0.000 0.000 #14 3.559 3.177 3.199 0.022 0.003 3.199 0.000 0.000 #15 3.561 3.200 3.223 0.023 0.004 3.223 0.000 0.000 #16 3.561 3.192 3.215 0.023 0.004 3.215 0.000 0.000 #17 3.560 3.195 3.214 0.019 0.000 3.214 0.000 0.000 #18 3.560 3.196 3.218 0.023 0.003 3.219 0.001 0.001 #19 3.559 3.185 3.206 0.022 0.002 3.206 0.000 0.000 #20 3.556 3.163 3.181 0.018 -0.001 3.181 0.000 0.000 #21 3.560 3.195 3.214 0.019 0.000 3.214 0.000 0.000 #22 3.560 3.196 3.213 0.017 -0.002 3.214 0.001 0.001

In Table 1 above, measurement time A is included in the idle section immediately after discharging, and measurement points B and C are included in the idle section in a state in which the battery system 1 is left unattended for a predetermined time or longer. Table 1 above exemplifies the voltage change in a state where an internal short circuit occurs in cell #7 among the plurality of cells (#1 to #22). Referring to Table 1 above, when an abnormal cell is detected only by a cell voltage value, the occurrence of an abnormality in cell #7 cannot be detected in a state in which the plurality of cells #1 to #22 are balanced. In addition, in the case of a cell in which the cell voltage value is relatively low compared to other cells due to the characteristics (degradation, etc.) of the cell 100, such as cell #20, it may be mistakenly recognized as an abnormal cell even though an internal short circuit does not occur. .

On the other hand, when an abnormal cell is detected using the voltage variation deviation as in the embodiment, the cell #20 has a voltage variation variation in both the BA time interval and the CB time interval similar to other cells, so that it is not mistakenly recognized as an abnormal cell. can In addition, in the case of cell #7 in which an actual internal short circuit occurs, the absolute deviation of the voltage change amount appears as the highest value in both the B-A time period and the C-B time period, so that it can be detected as an abnormal cell.

When an abnormal cell is detected in the above-described manner, the detection unit 22 may transmit an alarm signal for notifying the abnormal cell to the control unit 23 . In this case, the detection unit 22 may transmit identification information of the cell 100 identified as an abnormal cell included in the alarm signal.

When an alarm signal for notifying an abnormal cell is received from the detection unit 22, the control unit 23 transmits it to a higher-level controller (not shown) or executes protective operations to protect the battery module 10 from a dangerous situation. have.

In addition, when a request is received from the host controller, the control unit 23 receives a voltage change amount and a voltage change amount deviation for each cell 100 in each time period from the memory 24, or an abnormal cell or a group of abnormal cells in each time period. It can also read information and transmit it to the upper controller. In this case, the host controller displays information on the voltage change amount and voltage change amount deviation for each cell 100 in each time period, or the information on the abnormal cell or the abnormal cell candidate group in each time period on the screen, so that the administrator can control the cell 100 to check their abnormal status.

In the battery system 1 described above, the measurement unit 21 , the detection unit 22 , or the control unit 23 is performed by one or more central processing units (CPUs) or other chipsets, microprocessors, and the like, implemented by a processor. can be

4 schematically illustrates a method for detecting an abnormal cell in a battery system according to an embodiment of the present invention. The abnormal cell detection method of FIG. 4 may be performed by the abnormal cell detection apparatus 20 described with reference to FIG. 1 .

Referring to FIG. 4 , the abnormal cell detecting apparatus 20 according to an embodiment of the present invention continuously measures the cell voltage values of the plurality of cells 100 constituting the battery module 10 ( S11 ). Then, based on the measured cell voltage values, the voltage change amount for each cell 100 is calculated for a predetermined time period (S12), and the voltage change amount (or voltage change rate) deviation for each cell 100 is calculated therefrom ( S12 ). do (S13). Here, the abnormal cell detection apparatus 20 may calculate a voltage change amount and a voltage change amount deviation by using voltage values measured in an idle period in which the battery module 10 is in an idle state.

When the deviation of the voltage change amount (or voltage change rate) for each cell 100 is calculated through the steps S12 and S13 , the abnormal cell detection apparatus 20 monitors this and determines an abnormal cell among the plurality of cells 100 ( S14 ). ).

In step S14 , the abnormal cell detecting apparatus 20 may determine a cell having the absolute deviation of the voltage change greater than or equal to a predetermined value or the maximum in the same time period among the plurality of cells 100 as an abnormal cell.

Also, in step S14, the abnormal cell detection apparatus 20 registers at least one cell 100 selected in the order of the highest absolute deviation of the voltage change in each time interval as an abnormal cell candidate group, and in one or more time intervals, the abnormal cell The cell 100 registered as a candidate group may be determined as an abnormal cell.

Also, in step S14 , the abnormal cell detecting apparatus 20 may detect a cell having a voltage change rate deviation equal to or greater than a predetermined value in a predetermined time interval among the plurality of cells 100 as an abnormal cell.

In addition, in step S14 , the abnormal cell detection apparatus 20 registers at least one cell 100 selected in the order of the highest absolute deviation of the voltage change rate in each time interval as an abnormal cell candidate group, and the abnormal cell in one or more time intervals The cell 100 registered as a candidate group may be detected as an abnormal cell.

When an abnormal cell is detected among the plurality of cells 100 through the step S14 ( S15 ), the abnormal cell detection apparatus 20 generates an alarm signal notifying it ( S16 ).

As described above, the abnormal cell detecting apparatus 20 according to the embodiment may detect the occurrence of an internal short circuit of the cell even while the battery system 1 is left unattended. And, by using the voltage change amount or the voltage change rate deviation for abnormal cell determination, it is possible to avoid a situation in which instantaneous voltage fluctuations due to noise are mistakenly recognized as an internal short circuit. In addition, it is possible to also detect the occurrence of a minute internal short circuit in which the voltage change is relatively insignificant through continuous monitoring of the voltage change amount deviation or the voltage change rate deviation.

An electronic or electrical device and/or any other related device or component according to the embodiments of the invention described herein may include any suitable hardware, firmware (eg, an application-specific integrated circuit), It may be implemented using software, or a combination of software, firmware, and hardware. For example, the various components of these devices may be formed on one integrated circuit (IC) chip or on separate IC chips. In addition, various components of these devices may be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or one substrate. can The electrical connection or interconnection described herein may be implemented, for example, by wiring or conductive elements on a PCB or other type of circuit carrier. The conductive element may include pins and/or metallizations, such as surface metallizations, for example, and may include conductive polymers or ceramics. Electrical energy may also be transmitted via a wireless connection using, for example, electromagnetic radiation or light.

In addition, the various components of these devices run on one or more processors, within the one or more computing devices, execute computer program instructions, and interact with other system components to perform the various functions described herein. or a thread. The computer program instructions are stored in a memory that may be implemented in a computing device using a standard memory device, such as, for example, random access memory (RAM). The computer program instructions may also be stored on other non-transitory computer readable media, such as, for example, a CD-ROM, flash drive, or the like.

In addition, those skilled in the art will appreciate that the functionality of various computing devices may be combined or integrated into a single computing device, or the functionality of a particular computing device may be distributed across one or more other computing devices without departing from the scope of exemplary embodiments of the present invention. It should be recognized that it can be

Claims (13)

An apparatus for detecting abnormal cells of a battery module including a plurality of cells, the apparatus comprising:
A measuring unit that measures the cell voltage values of the plurality of cells while changing the measurement time, and
The voltage change amount and the voltage change amount deviation of each of the plurality of cells are calculated for a predetermined time period based on the cell voltage values, and the voltage change amount deviation calculated for each of the plurality of cells while changing the time period a detection unit configured to detect an abnormal cell among the plurality of cells based on the
The detector compares cell voltage values measured at two different measurement points included in the time period for each of the plurality of cells to calculate the voltage change amount, and an average value of the voltage change amounts of the plurality of cells and calculating the voltage change amount deviation of each of the plurality of cells from the difference between the voltage change amount of each of the plurality of cells,
The time interval between the measurement times of the measuring unit is changed according to whether the battery module is charging or discharging, or a time elapsed from the charging/discharging time point of the battery module. According to claim 1,
The detection unit,
An abnormal cell detection apparatus for detecting a cell in which the absolute value of the voltage variation deviation in the same time period is the maximum or is greater than or equal to a predetermined value as an abnormal cell. 2. The method of claim 1
The detection unit,
Abnormal cell detection, in which at least one cell selected in the order of the highest absolute value of the voltage variation deviation in each time interval is registered as an abnormal cell candidate group, and cells registered as the abnormal cell candidate group in one or more time intervals are detected as abnormal cells Device. According to claim 1,
The detection unit,
An abnormal cell detection apparatus, wherein a voltage change rate deviation is calculated from the voltage change amount deviation in each time section, and a cell having an absolute value of the voltage change rate deviation equal to or greater than a predetermined value is detected as an abnormal cell. 2. The method of claim 1
The detection unit,
The voltage change rate deviation is calculated from the voltage change amount deviation in each time period, and at least one cell selected in the order of the highest absolute value of the voltage change rate deviation in each time period is registered as an abnormal cell candidate group, and in one or more time periods An abnormal cell detection apparatus for detecting a cell registered as the abnormal cell candidate group as an abnormal cell. According to claim 1,
The detection unit,
and calculating the voltage change amount and the voltage change amount deviation by using cell voltage values measured when the battery module is in a rest state among the cell voltage values measured by the measuring unit. A battery module including a plurality of cells, and
A battery system comprising the abnormal cell detection device of any one of claims 1 to 6. A method for detecting abnormal cells in a battery system including a plurality of cells, the method comprising:
measuring the cell voltage values of the plurality of cells while changing the measurement timing;
Calculating a voltage change amount and a voltage change amount deviation of each of the plurality of cells from the cell voltage values measured for a predetermined time period, and
Detecting an abnormal cell among the plurality of cells based on the voltage variation calculated for each of the plurality of cells while changing the time period,
The calculating step is
Comparing cell voltage values measured at two different measurement points included in the time period for each of the plurality of cells to calculate the voltage change amount, and
calculating a deviation of the voltage change amount of each of the plurality of cells from a difference between the average value of the voltage change amounts of the plurality of cells and the voltage change amount of each of the plurality of cells,
In the measuring step, a time interval between measurement time points is changed according to whether the plurality of cells are being charged or discharged, or a time elapsed from the charging or discharging end time point of the plurality of cells, abnormal cell detection method. 9. The method of claim 8,
The detecting step is
and detecting, as an abnormal cell, a cell in which the absolute value of the voltage variation deviation in the same time period is the maximum or is greater than or equal to a predetermined value. 9. The method of claim 8,
The detecting step is
Registering at least one cell selected in the order of the highest absolute value of the voltage variation deviation in each time interval as an abnormal cell candidate group, and
Detecting a cell registered as the abnormal cell candidate group as an abnormal cell in one or more time intervals, the abnormal cell detection method. 9. The method of claim 8,
The detecting step is
calculating a voltage change rate deviation from the voltage change amount deviation in each time interval; and
and detecting a cell in which the absolute value of the voltage change rate deviation is equal to or greater than a predetermined value as an abnormal cell. 9. The method of claim 8,
The detecting step is
calculating a voltage change rate deviation from the voltage change amount deviation in each time interval;
Registering at least one cell selected in the order of the highest absolute value of the voltage change rate deviation in each time interval as an abnormal cell candidate group, and
Detecting a cell registered as the abnormal cell candidate group as an abnormal cell in one or more time intervals, the abnormal cell detection method. 9. The method of claim 8,
Calculating the voltage change amount comprises:
and calculating the voltage change amount using cell voltage values measured when the battery system is in a rest state among the cell voltage values.

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