JP2020056756A - Method for detecting abnormality of current sensor - Google Patents

Abstract

To accurately detect an abnormality of a current sensor detecting a charge current of a secondary battery.SOLUTION: The method for detecting an abnormality includes: monitoring the voltage of a battery detected by a voltage sensor; calculating a first charge rate showing the charge rate of the battery based on the integrated value of the charge current of the battery detected by a first current sensor; calculating a second charge rate showing the charge rate of the battery based on the integrated value of the charge current of the battery detected by a second current sensor; and determining that the second current sensor is abnormal if the first charge rate is lower than the threshold charge rate determined by the full charge voltage and the second charge rate is higher than the threshold charge rate when the voltage of the battery is lower than the full charge voltage of the battery.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for detecting an abnormality of a current sensor.

  Rechargeable secondary batteries are widely used in various fields. For example, an electric vehicle or a plug-in hybrid vehicle includes a secondary battery for supplying a current to a traveling motor.

  Secondary batteries are often charged with a specified value of current. In this case, the charging controller controls the charging operation while monitoring the charging current detected using the current sensor. For this reason, when an abnormality occurs in the gain of the current sensor that detects the charging current, the secondary battery may not be properly charged. Note that the gain of the current sensor corresponds to the ratio between the input current and the output voltage of the current sensor. Also, even when an offset error occurs due to an offset error of the current sensor, the secondary battery may not be able to be properly charged. Note that the offset error of the current sensor corresponds to the difference between the output voltage of the current sensor and the reference voltage when no current flows through the secondary battery. Also, when a current value fixing abnormality in which the output value of the current sensor is fixed to a predetermined value occurs, the secondary battery may not be able to be charged properly.

  To cope with this problem, for example, when a difference between an SOC (State of Charge) obtained based on a charging current detected by a current sensor and an SOC obtained based on a voltage detected by a voltage sensor is larger than a threshold value A technique for determining that a current sensor is abnormal has been proposed (for example, Patent Document 1). Further, techniques related to Patent Documents 2 to 4 are described.

JP 2012-088157 A JP 2010-104175 A JP 2013-217899 A JP 2012-058028 A

  However, in the method of comparing the SOC based on the measurement value of the current sensor with the SOC based on the measurement value of the voltage sensor, it may not be possible to determine which of the current sensor and the voltage sensor has failed.

  An object according to one aspect of the present invention is to accurately detect an abnormality of a current sensor that detects a charging current of a secondary battery.

  The abnormality detection method according to one aspect of the present invention monitors a voltage of a battery detected using a voltage sensor, and based on an integrated value of a charging current of the battery detected using a first current sensor, Calculating a first charging rate representing the charging rate of the battery, and calculating a second charging rate representing the charging rate of the battery based on an integrated value of the charging current of the battery detected using a second current sensor. Calculating, when the voltage of the battery is a predetermined full charge voltage, the first charging rate is within a threshold range corresponding to the full charging voltage, and the second charging rate is If it is out of the threshold range, it is determined that the second current sensor is abnormal.

  In the above method, when the voltage of the battery is at the full charge voltage, the charge rate of the battery should be within the threshold range corresponding to the full charge voltage. Therefore, when the voltage of the battery is the full charge voltage, if the second charging rate calculated based on the charging current detected using the second current sensor is out of the threshold range, the voltage sensor or It is considered that an abnormality has occurred in at least one of the second current sensors. Here, if the first charging rate calculated based on the charging current detected using the first current sensor falls within a threshold range when the voltage of the battery is the full charge voltage, the voltage sensor And the first current sensor are both considered normal. Therefore, if the first charging rate is within the threshold range and the second charging rate is out of the threshold range when the battery voltage is at the full charge voltage, the second current sensor is abnormal. Can be determined. That is, the current sensor in which the abnormality has occurred can be specified with high accuracy.

  When the voltage of the battery is at the full charge voltage, the first charging rate is within a threshold range, and the second charging rate is out of the threshold range, and the first charging rate is different from the first charging rate. The second current sensor may be determined to be abnormal only when the difference from the second state of charge is greater than a predetermined threshold. Here, in the case where the calculation result of the first charging rate and / or the second charging rate has an error, the first current sensor and the second current sensor may be in a normal state even though the first and second current sensors are normal. A state where the state of charge is within the threshold range and the second state of charge slightly deviates from the threshold range may occur. That is, erroneous detection may occur. Therefore, the above-described erroneous detection is avoided or suppressed by determining that the second current sensor is abnormal only when the difference between the first state of charge and the second state of charge is greater than a predetermined threshold. obtain.

  At the start of charging the battery, only when the initial values for calculating the first charging rate and the second charging rate are reset based on the voltage of the battery detected using the voltage sensor, respectively. It may be determined whether the first current sensor and the second current sensor are abnormal. Here, when the charging rate is calculated based on the integrated value of the charging current, errors in the calculation result may accumulate. When the presence or absence of an abnormality in the first current sensor and the second current sensor is determined using the charging rate in which the error has accumulated, the reliability is reduced. Therefore, by resetting the initial values for calculating the first charging rate and the second charging rate based on the voltage of the battery detected using the voltage sensor, the accumulation of errors is eliminated, and Of the current sensor and the second current sensor is improved.

  According to the above aspect, it is possible to accurately detect the abnormality of the current sensor that detects the charging current of the secondary battery.

FIG. 2 is a diagram illustrating an example of a battery pack in which the current sensor abnormality detection method according to the embodiment of the present invention is used. It is a figure showing an example of a charging operation. FIG. 7 is a diagram illustrating an example of a case where a gain abnormality of a current sensor is detected. 5 is a flowchart illustrating an example of an abnormality detection method.

  FIG. 1 shows an example of a battery pack in which an abnormality detection method for a current sensor according to an embodiment of the present invention is used. The battery pack 100 shown in FIG. 1 is mounted on, for example, an electric vehicle or a plug-in hybrid vehicle. In the following description, an electric vehicle or a plug-in hybrid vehicle may be referred to as an “electric vehicle”.

  As shown in FIG. 1, the battery pack 100 includes a battery 1, current sensors 2a and 2b, a voltage sensor 3, and a processor 10. Note that the battery pack 100 may include other circuit elements not shown in FIG.

  Battery 1 is a secondary battery, and can be charged by charging device 200. The charging device 200 can be attached to and detached from the battery pack 100. Further, the battery 1 can supply a current to a load (not shown). The load includes, for example, a motor of the electric vehicle.

  The current sensors 2a and 2b (first current sensor and second current sensor) are provided between the charging device 200 and the battery 1, and detect the charging current of the battery 1, respectively. The current sensors 2a and 2b are connected in series with each other. Each of the current sensors 2a and 2b is not particularly limited, but is configured using, for example, a Hall element. However, each of the current sensors 2a and 2b may be realized by another configuration. The voltage sensor 3 detects a voltage between the positive terminal and the negative terminal of the battery 1.

  Processor 10 controls a charging operation by charging device 200. For example, the processor 10 can provide the charging device 200 with a command value of a charging current. Further, the processor 10 can manage the state of the battery 1. Further, the processor 10 executes an abnormality detection process for detecting an abnormality of the current sensors 2a, 2b. That is, the processor 10 can operate as an abnormality detection device that detects an abnormality of the current sensors 2a and 2b.

  The abnormalities of the current sensors 2a and 2b include at least one of an abnormal gain, an abnormal offset, and an abnormal fixed current value, and the following embodiments will be described on the assumption that there is an abnormal gain. When an abnormality not limited to a gain abnormality is assumed, “gain abnormality” in the following embodiments can be replaced with “abnormal”.

  Further, in this embodiment, the processor 10 performs both the charge control and the state management of the battery 1, but the present invention is not limited to this configuration. That is, the charge control for giving the charging current command value to the charging device 200 and the state management for managing the state of the battery 1 may be executed by separate processors.

  The processor 10 includes a charge control unit 11, a voltage monitor 12, an SOC calculation unit 13, and a determination unit 14, as shown in FIG. The functions of the charge control unit 11, the voltage monitor 12, the SOC calculation unit 13, and the determination unit 14 are realized, for example, by the processor 10 executing a software program stored in a memory (not shown). In addition, the processor 10 can provide functions not shown in FIG.

  The charging control unit 11 controls the charging device 200 by giving a charging current command value to the charging device 200. Further, when the charging operation includes the constant current charging mode and the constant voltage charging mode, the charging control unit 11 may control the timing of switching from the constant current charging mode to the constant voltage charging mode. For example, at the start of the charging operation, the battery 1 is charged in the constant current charging mode. At this time, the charge control unit 11 monitors the voltage (closed circuit voltage: CCV) of the battery 1 detected by the voltage sensor 3. Then, when the voltage of the battery 1 reaches the full charge voltage, the charge control unit 11 switches the charge mode from the constant current charge mode to the constant voltage charge mode. In the constant voltage charging mode, the charging current is gradually reduced. Then, when the state where the charging current is sufficiently small continues for a predetermined time, the charging control unit 11 ends the charging operation.

  The voltage monitor 12 monitors the voltage of the battery 1 detected using the voltage sensor 3. As an example, voltage monitoring unit 12 monitors the voltage of battery 1 detected using voltage sensor 3 when charging operation of battery 1 from charging device 200 is being performed. In this case, the closed circuit voltage of the battery 1 is monitored. Further, the voltage monitoring unit 12 monitors the voltage of the battery 1 detected by using the voltage sensor 3 when the battery 1 is not used. In this case, the open circuit voltage (OCV) of the battery 1 is monitored.

The SOC calculator (charging rate calculator) 13 calculates SOC_a (first charging rate) representing the charging rate of the battery 1 based on the integrated value of the charging current of the battery 1 detected using the current sensor 2a. I do. Further, the SOC calculation unit 13 calculates SOC_b (second charging rate) representing the charging rate of the battery 1 based on the integrated value of the charging current of the battery 1 detected using the current sensor 2b. SOC (State of Charge) represents the current charge capacity with respect to the full charge capacity of the battery. That is, the SOC represents the charging rate of the battery. Therefore, the SOC of the battery 1 is calculated by, for example, equation (1).
SOC = SOC before charging + 100 × current integrated value / full charge capacity (1)

  The pre-charge SOC is determined based on, for example, the voltage of the battery 1 at the start of charging (here, the open circuit voltage). Note that the SOC of the battery 1 uniquely corresponds to the voltage of the battery 1. Therefore, SOC calculating section 13 can calculate the pre-charge SOC by acquiring the output signal of voltage sensor 3 at the start of charging. However, SOC calculating section 13 may determine the pre-charge SOC by another method. For example, the SOC at an arbitrary time can be calculated by setting an initial SOC value based on the open circuit voltage of the battery 1 at a certain time, and then monitoring and integrating the output current and the charging current of the battery 1. In this case, SOC calculating section 13 can obtain the pre-charge SOC by integrating the current from the time when the SOC initial value is set to the time when charging starts.

  The integrated current value of the expression (1) represents the integrated value of the charging current of the battery 1 detected by the current sensors 2a and 2b. The full charge capacity of the expression (1) is estimated using, for example, aging information on the full charge capacity of the battery 1. The aging information indicates a change in the full charge capacity of the battery 1 with the passage of time, and is created in advance in accordance with the structure of the battery 1 and the material of the battery 1. Therefore, SOC calculating unit 13 can estimate the full charge capacity of battery 1 based on the lapse of time from when battery 1 was manufactured.

  As described above, SOC calculation unit 13 calculates SOC_a corresponding to the charging current detected using current sensor 2a and SOC_b corresponding to the charging current detected using current sensor 2b. Here, if the gains of the current sensors 2a and 2b are normal, SOC_a and SOC_b should be substantially the same. In other words, when SOC_a and SOC_b are different from each other, it is considered that the gain of at least one of the current sensors 2a and 2b is abnormal.

  The determination unit 14 detects a gain abnormality of the current sensors 2a and 2b based on the voltage of the battery 1 detected by the voltage sensor 3 and the SOC_a and SOC_b calculated by the SOC calculation unit 13. For example, when the voltage of the battery 1 is a predetermined full charge voltage and the SOC_a falls within a threshold range corresponding to the full charge voltage and the SOC_b falls outside the threshold range, the determination unit 14 Determines that the gain of the current sensor 2b is abnormal. Similarly, when SOC_b is within the threshold range and SOC_a is outside the threshold range when the voltage of battery 1 is at the full charge voltage, determination unit 14 determines that the gain of current sensor 2a is abnormal. Is determined.

  The “threshold range corresponding to the full charge voltage” is expressed in terms of SOC (that is, the charging rate of the battery 1), and is set to include the SOC corresponding to the full charge voltage. The “SOC corresponding to the full charge voltage” is 100% in this embodiment. The lower limit of the threshold range is obtained by subtracting Δ1 from 100%, and the upper limit of the threshold range is obtained by adding Δ2 to 100%. That is, the threshold range is from “100−Δ1 (%)” to “100 + Δ2 (%)”.

  Δ1 and Δ2 may be the same or different from each other. Here, if Δ1 and Δ2 are too large, the threshold range becomes wide, and there is a possibility that a detection omission that cannot detect an abnormal gain of the current sensor may occur. On the other hand, if Δ1 and Δ2 are too small, the threshold range becomes narrow, and erroneous detection of a normal current sensor that may detect an abnormal gain may occur. Therefore, Δ1 and Δ2 defining the threshold range need to be appropriately determined. Δ1 and Δ2 are not particularly limited, but are, for example, about several percent in terms of SOC. Note that Δ1 and Δ2 are set to absorb detection errors of the current sensors 2a and 2b and the voltage sensor 3.

  FIG. 2 shows an example of a charging operation of the battery pack 100. In this embodiment, the charging operation is started at time T1. After the start of charging, charging device 200 charges battery 1 in the constant current charging mode. That is, as shown in FIG. 2A, the charging device 200 charges the battery 1 with a constant charging current Icc according to a command value given from the charging control unit 11. Then, the voltage of the battery 1 (that is, the closed circuit voltage) increases as shown in FIG.

  At this time, the voltage monitoring unit 12 monitors the voltage of the battery 1. When the voltage of the battery 1 reaches a predetermined full charge voltage, the charge control unit 11 switches the charge mode of the battery 1 from the constant current charge mode to the constant voltage charge mode. In the example shown in FIG. 2, at time T2, the voltage of the battery 1 reaches the full charge voltage, and the switching from the constant current charging mode to the constant voltage charging mode is performed.

  In the constant voltage charging mode, the charging current is gradually reduced. At this time, the voltage of the battery 1 is maintained at substantially the full charge voltage. Then, when the state where the charging current is sufficiently small continues for a predetermined time, the charging control unit 11 ends the charging operation. In the example shown in FIG. 2, the charging operation has been completed at time T3.

  Here, it is assumed that the gains of the current sensors 2a and 2b are both normal, and both the current sensors 2a and 2b correctly detect the charging current. In this case, as shown in FIG. 2C, the output signals of the current sensors 2a and 2b (that is, the charging currents detected by the current sensors 2a and 2b) substantially match each other.

  At this time, the SOC calculation unit 13 calculates SOC_a and SOC_b based on the charging current detected by the current sensors 2a and 2b, respectively. Here, when the current sensors 2a and 2b each detect the charging current correctly, the SOC_a and the SOC_b substantially coincide with each other as shown in FIG. It gradually increases. Then, when the voltage of battery 1 reaches the full charge voltage at time T2, SOC_a and SOC_b each reach the SOC (ie, 100%) corresponding to the full charge voltage. Therefore, when the voltage of battery 1 reaches the full charge voltage at time T2, SOC_a and SOC_b are both within the threshold range.

  Actually, the charging current flows even after the transition from the constant current charging mode to the constant voltage charging mode, so that the SOC_a and the SOC_b increase after the time T2. However, compared to the constant current charging mode, the charging current in the constant voltage charging mode is smaller, and the charging time is shorter. Therefore, in the embodiment shown in FIG. 2, the increase in SOC due to the constant voltage charging mode executed after time T2 is ignored.

  In the period T2 to T3, the battery 1 is charged in the constant voltage charging mode, so that the voltage of the battery 1 is maintained at the full charge voltage. That is, when the charging operation is completed, the voltage of the battery 1 is the full charge voltage.

  When the voltage of the battery 1 is the full charge voltage, the determination unit 14 determines whether or not the current sensors 2a and 2b have a gain abnormality. As an example, the determination unit 14 determines whether the current sensors 2a and 2b have a gain abnormality at the time when the charging operation ends or after the charging operation ends. Here, in the example shown in FIG. 2, since both SOC_a and SOC_b fall within the threshold range, abnormal gain of the current sensors 2a and 2b is not detected.

  FIG. 3 shows an example of a case where an abnormal gain of the current sensor is detected. Here, as in the example shown in FIG. 2, battery 1 is charged in the constant current charging mode in periods T1 and T2, and battery 1 is charged in the constant voltage charging mode in periods T2 and T3. That is, as shown in FIG. 3A, a constant charging current Icc is supplied in the period T1 to T2, and as shown in FIG. 3B, at time T2, the voltage of the battery 1 reaches the full charge voltage. Thereafter, the voltage of the battery 1 is maintained at the full charge voltage.

  In this embodiment, the current sensor 2a can correctly detect the current, but the current sensor 2b cannot correctly detect the current. Specifically, the gain of the current sensor 2b is smaller than a normal value. As a result, as shown in FIG. 3C, the current value detected by the current sensor 2b becomes smaller than the current value detected by the current sensor 2a.

  The processor 10 executes the abnormality detection processing when the voltage of the battery 1 is the full charge voltage. In this embodiment, for example, the processor 10 executes the abnormality detection processing when the charging operation ends at time T3. However, the processor 10 may execute the abnormality detection processing after the charging operation is completed and the polarization of the battery 1 is resolved. Further, the processor 10 may execute the abnormality detection processing when charging is performed in the constant voltage charging mode.

  The abnormality detection process includes a process of monitoring the closed circuit voltage of the battery 1 based on the output signal of the voltage sensor 3, a process of calculating SOC_a and SOC_b based on the output signals of the current sensors 2a and 2b, and a process of calculating the closed circuit voltage and SOC_a. , SOC_b to determine whether there is a gain abnormality in the current sensors 2a and 2b.

The determination unit 14 determines that the gain of the current sensor is abnormal when the following two requirements are satisfied when the voltage of the battery 1 is the fully charged voltage.
(1) The SOC calculated based on the charging current detected by one of the current sensors 2a and 2b is within a threshold range. (2) The charging current detected by the other of the current sensors 2a and 2b SOC calculated based on the threshold value is out of the threshold range

  In the example shown in FIG. 3, it is assumed that the abnormality detection processing is executed at time T3. At time T3, the voltage of battery 1 is the full charge voltage.

  At time T3, as shown in FIG. 3D, SOC_a falls within the threshold range. That is, the above requirement (1) is satisfied. SOC_b is out of the threshold range. That is, the above requirement (2) is also satisfied. In this case, the determination unit 14 determines that the gain of the current sensor 2b is abnormal. Here, SOC_b at time T3 is smaller than the lower limit of the threshold range. Therefore, the determination unit 14 determines that the gain of the current sensor 2b is smaller than the normal value.

  As described above, in the abnormality detection processing, the gain state of the current sensor is detected based on the requirements (1) and (2) described above. Here, assuming that the gain of the current sensor is normal, when the voltage of the battery 1 is the full charge voltage, the SOC corresponding to the current sensor should be within the threshold range. Therefore, if the SOC corresponding to the current sensor is out of the threshold range when the voltage of the battery 1 is the full charge voltage, it is assumed that some abnormal state has occurred.

  In the example shown in FIG. 3, for example, at time T3, the voltage of the battery 1 is the full charge voltage, but the SOC_b corresponding to the current sensor 2b is out of the threshold range. However, in this situation alone, it is not possible to determine which of the voltage sensor 3 and the current sensor 2b is abnormal. Therefore, the determination unit 14 refers to the SOC_a corresponding to the current sensor 2a. Here, at time T3, when the voltage of the battery 1 is the full charge voltage, the SOC_a corresponding to the current sensor 2a is within the threshold range. That is, since the output signal of the voltage sensor 3 and the output signal of the current sensor 2a do not contradict each other, it is determined that the voltage sensor 3 and the current sensor 2a are normal. Therefore, at time T3, the determination unit 14 determines that the gain of the current sensor 2b is abnormal.

  FIG. 4 is a flowchart illustrating an example of the abnormality detection method according to the embodiment of the present invention. In this embodiment, the abnormality detection processing is executed when the charging operation is completed.

  In S1, the charging control unit 11 starts charging the battery 1 in the constant current charging mode. Then, a current is supplied from the charging device 200 to the battery 1, and the voltage of the battery 1 (here, the closed circuit voltage CCV) gradually increases.

  In S2, the voltage monitoring unit 12 determines whether the closed circuit voltage CCV of the battery 1 detected by the voltage sensor 3 has reached the full charge voltage. If the closed circuit voltage CCV has not reached the full charge voltage, the charge control unit 11 continues the charging operation in the constant current charge mode.

  When the closed circuit voltage CCV of the battery 1 reaches the full charge voltage, in S3, the charge control unit 11 switches the charge mode from the constant current charge mode to the constant voltage charge mode. In the constant voltage charging mode, the charging current is gradually reduced while the closed circuit voltage CCV of the battery 1 is maintained at the full charging voltage.

  In S4, the charging control unit 11 determines whether to end the charging operation. In this embodiment, if the charging current detected by the current sensors 2a and 2b continues to drop below a predetermined value for a predetermined time, the charging control unit 11 determines that the charging operation should be terminated. Then, after the end of the charging operation, the process of the processor 10 proceeds to S5. When the processing after S5 is executed, the charging operation has been completed, so that the voltage of the battery 1 is substantially maintained at the full charge voltage.

  In S5, the SOC calculation unit 13 calculates SOC_a and SOC_b. That is, the SOC calculation unit 13 calculates the SOC_a using the integrated value of the charging current detected by the current sensor 2a. The SOC calculation unit 13 calculates the SOC_b using the integrated value of the charging current detected by the current sensor 2b.

  In S6 to S8, the determination unit 14 determines the state of the current sensors 2a, 2b. Specifically, when SOC_a and SOC_b are both within the threshold range (S6: Yes, S7: Yes), the determination unit 14 determines in S9 that the gains of the current sensors 2a and 2b are normal. I do. That is, no gain abnormality is detected for any of the current sensors.

  When SOC_a is within the threshold range and SOC_b is out of the threshold range (S6: Yes, S7: No), the determination unit 14 determines in S10 that the gain of the current sensor 2b is abnormal. I do. When SOC_a is out of the threshold range and SOC_b is in the threshold range (S6: No, S8: Yes), the determination unit 14 determines in S11 that the gain of the current sensor 2a is abnormal. Is determined.

  When both SOC_a and SOC_b are out of the threshold range (S6: No, S8: No), the determination unit 14 determines which of the voltage sensor 3 and the current sensors 2a, 2b is abnormal. Can not. In this case, the determination unit 14 outputs an error message in S12.

<Variation 1>
Output signals of the voltage sensor 3 and the current sensors 2a and 2b include an error. In addition, when SOC_a and SOC_b are calculated based on the integrated values of the charging currents detected by the current sensors 2a and 2b, errors in SOC_a and SOC_b may accumulate. For this reason, when the voltage of the battery 1 is at the full charge voltage, one SOC is within the threshold range and the other SOC is out of the threshold range, and the difference between the two SOCs is small. However, the reliability of the determination result of the determination unit 14 is not always high.

  Therefore, the determination unit 14 may determine whether or not the current sensor has a gain abnormality only when the difference between SOC_a and SOC_b is larger than a predetermined threshold. By introducing this procedure, the reliability of the determination result of the determination unit 14 is improved. Specifically, the possibility that the gain of the current sensor is determined to be abnormal although the gain is normal is reduced.

<Variation 2>
As described above, when SOC_a and SOC_b are calculated based on the integrated values of the charging currents detected by the current sensors 2a and 2b, errors in SOC_a and SOC_b may accumulate. Here, the accumulation of this error can be performed, for example, by resetting the initial values for calculating the SOC_a and the SOC_b based on the closed-circuit voltage detected by using the voltage sensor 3 at the start of charging the battery 1. Can be eliminated.

  Therefore, the determination unit 14 determines whether or not the initial values for calculating the SOC_a and the SOC_b based on the voltage of the battery 1 detected using the voltage sensor 3 at the start of charging are reset only when the current sensor 2a is reset. 2b, the presence or absence of the gain abnormality may be determined. In this case, the accuracy of the SOC_a and the SOC_b increases, so that the reliability of the determination result of the determination unit 14 improves. The reset of the initial values for calculating the SOC_a and the SOC_b is periodically performed by, for example, the SOC calculation unit 13.

DESCRIPTION OF SYMBOLS 1 Battery 2a, 2b Current sensor 3 Voltage sensor 10 Processor 11 Charge control unit 12 Voltage monitor unit 13 SOC calculation unit 14 Judgment unit 100 Battery pack

Claims (4)

Monitor the battery voltage detected using the voltage sensor,
Calculating a first charging rate indicating a charging rate of the battery based on an integrated value of the charging current of the battery detected using a first current sensor;
Calculating a second charging rate representing the charging rate of the battery based on an integrated value of the charging current of the battery detected using a second current sensor;
When the voltage of the battery is a predetermined full charge voltage, the first charging rate falls within a threshold range corresponding to the full charging voltage, and the second charging rate falls within the threshold range. If not, determining that the second current sensor is abnormal. When the voltage of the battery is the full charge voltage, the first charging rate is within the threshold range, and the second charging rate is out of the threshold range, and The abnormality detection method according to claim 1, wherein if the difference between the first charging rate and the second charging rate is larger than a predetermined threshold value, it is determined that the second current sensor is abnormal. At the start of charging the battery, initial values for calculating the first charging rate and the second charging rate are reset based on the voltage of the battery detected using the voltage sensor. The abnormality detection method according to claim 1, further comprising: determining whether there is an abnormality in the first current sensor and the second current sensor. Batteries and
A voltage sensor for detecting a voltage of the battery;
A first current sensor for detecting a charging current of the battery;
A second current sensor connected in series to the first current sensor and detecting a charging current of the battery;
A voltage monitoring unit that monitors the voltage of the battery detected using the voltage sensor,
Calculating a first charging rate indicating a charging rate of the battery based on an integrated value of the charging current of the battery detected using the first current sensor, and detecting the charging rate using the second current sensor; A charging rate calculation unit that calculates a second charging rate representing the charging rate of the battery based on the integrated value of the charging current of the battery,
When the voltage of the battery is a predetermined full charge voltage, the first charging rate falls within a threshold range corresponding to the full charging voltage, and the second charging rate falls within the threshold range. If not, a determination unit that determines that the second current sensor is abnormal,
A battery pack comprising:

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