JP2013118757A - Battery pack control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack control device which can determine the type of abnormality in the battery.SOLUTION: There is provided a control device for a battery pack 100 which incorporates a battery pack including a plurality of unit cells and voltage detection means of detecting the voltage value of the unit cells. The control device comprises: adjustment means of adjusting the voltages or the charging states of the plurality of unit cells C1 to CN to a prescribed target value; predicted value arithmetic means of predicting an adjustment time in which a variation in the voltages or the charging states of the plurality of unit cells C1 to CN is adjusted by the adjustment means or an adjustment count per unit time or an adjustment amount made by the adjustment means as a predicted value from the voltage values of or a voltage difference between the plurality of unit cells C1 to CN; measured value arithmetic means of calculating, as a measured value, an adjustment time actually required for the voltages or the charging states of the plurality of unit cells C1 to CN to be adjusted to the target value by using the adjustment means or an adjustment count per unit time of adjustment actually made by using the adjustment means or an adjustment amount of adjustment actually made by using the adjustment means; and determination means of determining the type of abnormality in the battery pack 100 by using the predicted and the measured values.

Description

  The present invention relates to a control device for an assembled battery.

  An apparatus for detecting an abnormality in a power storage device configured by connecting a plurality of power storage units including at least one power storage element, wherein a plurality of processes for equalizing variation in capacity or voltage of each of the plurality of power storage units When the equalization processing unit finishes one equalization process, the time interval between the one equalization process executed before the one equalization process is calculated. When the time interval calculated by the equalization processing interval calculation unit and the equalization processing interval calculation unit is shorter than the time set as the power storage device should be determined to be in a state close to an abnormal state, An abnormality occurrence warning determination unit that determines that the power storage device is in a state close to an abnormal state, and measurement after the determination when the abnormality occurrence warning determination unit determines that the power storage device is in a state close to an abnormal state Said storage An abnormality determination value calculation unit that calculates an abnormality determination value that is obtained by integrating the absolute value of the charge / discharge current of the power storage device using the charge / discharge capacity of the device, and an abnormality determination value that is calculated by the abnormality determination value calculation unit. An abnormality detection of a power storage device comprising: an abnormality determination processing unit that determines that the power storage device is in an abnormal state when the power storage device is equal to or greater than a predetermined reference value set to be determined as an abnormal state. An apparatus is known (Patent Document 1).

JP 2008-134060 A

  However, in order to distinguish the types of battery abnormalities, it is not sufficient to detect that the time interval of the process for equalizing the variation of the plurality of storage batteries has become short. There is a problem that it is impossible to distinguish and detect the type of abnormality of the battery.

  The problem to be solved by the present invention is to provide a control apparatus for a battery pack that can determine the type of battery abnormality.

  The present invention predicts an adjustment time for adjusting variations in voltage or charge state of a plurality of single cells, the number of adjustments per unit time, or an adjustment capacity from a difference in voltage values between the plurality of single cells as a predicted value. Then, the adjustment time actually required until the voltage or charging state of a plurality of single cells is adjusted to the target value, or the number of adjustments per unit time is calculated as an actual measurement value, and the predicted value and the The problem is solved by determining the type of abnormality of the assembled battery using the measured value.

  According to the present invention, since the change in the actual measurement value with respect to the predicted value differs depending on the type of abnormality in the assembled battery, the type of abnormality in the assembled battery can be determined by detecting the change.

It is a block diagram of the assembled battery system containing the control apparatus of the assembled battery which concerns on embodiment of this invention. It is a block diagram of the battery controller of FIG. 2 is a graph showing characteristics of adjustment time with respect to voltage variation per unit time in the assembled battery of FIG. 1. It is a graph which shows the characteristic of the predicted value per hour calculated by the prediction part of FIG. 2, and an actual measurement part, and an actual measurement value. It is a graph which shows the voltage characteristic with respect to the capacity | capacitance in the assembled battery of FIG. It is a graph which shows the voltage characteristic with respect to the capacity | capacitance in the assembled battery of FIG. FIG. 2 is a circuit diagram of the unit cell of FIG. 1 and a capacity adjusting resistor. It is a graph which shows the characteristic of the deviation degree per time calculated by the prediction part and measurement part of FIG. It is a flowchart which shows the control procedure in the battery controller of FIG. It is a graph which shows the characteristic of the deviation degree per time calculated by the estimation part and the measurement part in the control apparatus of the assembled battery which concerns on other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< First Embodiment >>
FIG. 1 is a configuration diagram of an assembled battery system including an assembled battery control device according to the present embodiment. In the following, a case where the assembled battery system according to the present embodiment is used as a battery for a vehicle such as a hybrid vehicle or an electric vehicle will be described as an example.

  As shown in FIG. 1, the assembled battery system according to the present embodiment includes an assembled battery 100 including a plurality of unit cells C1 to CN connected in series, a load 200 electrically connected to both ends of the assembled battery 100, and an assembled battery. A capacity adjustment circuit 400 for adjusting the capacity of the battery 100 and a battery controller 500 for controlling the entire assembled battery system are provided.

  The assembled battery 100 is configured by connecting N unit cells C1 to CN in series. Examples of the single cells C1 to CN include alkaline storage batteries such as nickel metal hydride batteries and organic electrolyte secondary batteries such as lithium ion batteries. In this embodiment, lithium ion batteries are used as the single cells C1 to CN. An example will be described. In addition, the single cells C1 to CN are connected in parallel, and include a plurality of batteries that have the same terminal voltage that can be measured and can be regarded as single cells. Note that the number N of unit cells is not particularly limited, and can be appropriately set as desired. In addition, the assembled battery 100 includes a temperature sensor 102 for measuring the temperature of the single cells C <b> 1 to CN constituting the assembled battery 100. The battery temperature measured by the temperature sensor 102 is transmitted to the battery controller 500.

  A capacity adjustment circuit 400 is connected in parallel to each of the N unit cells C <b> 1 to CN constituting the assembled battery 100. The capacity adjustment circuit 400 includes a resistor 401 and a switch 402. The capacity adjustment of the cells C1 to CN can be performed by closing the switch 402 and performing capacity adjustment discharge of the cells C1 to CN. Yes. The opening / closing of each switch 402 is controlled by the battery controller 500.

  The load 200 is, for example, a motor and an inverter mounted on a hybrid vehicle, an electric motor vehicle, or the like. For example, during regenerative control, the load 200 is reversely converted into electric energy via the motor and the inverter, and the assembled battery 100 is charged. It is possible. The assembled battery 100 can be charged by being connected to an external power source (not shown), for example.

  FIG. 2 is a functional block diagram of the battery controller 500. As shown in FIG. 2, the battery controller 500 includes a voltage detection unit 501, a current detection unit 502, a battery temperature detection unit 503, a capacity adjustment unit 504, a control unit 505, an abnormality determination unit 506, a prediction unit 507, a storage unit 508, An actual measurement unit 509, a notification unit 510, and a communication unit 511 are provided.

  The voltage detection unit 501 time-series the voltage values of the terminal voltages of the single cells C1 to CN constituting the assembled battery 100 at a predetermined cycle via a plurality of terminal lines connected to the single cells C1 to CN. The terminal voltage of each of the unit cells C1 to CN detected by measurement is converted from an analog signal to a digital signal and sent to the control unit 505. In addition, as a method of measuring the terminal voltage of each cell C1-CN, a flying capacitor system etc. are mentioned, for example.

  The current detection unit 502 acquires the charging / discharging current detected by the current sensor 300 at a predetermined period, converts the acquired charging / discharging current from an analog signal to a digital signal, and sends the converted signal to the control unit 505. Note that the current sensor 300 includes, for example, a resistance element, a current transformer, and the like.

  The battery temperature detection unit 503 acquires the temperatures of the individual cells C1 to CN measured by the temperature sensor 102 provided in the assembled battery 100 at a predetermined cycle, and the acquired temperatures of the individual cells C1 to CN are analog signals. Is converted into a digital signal and sent to the control unit 505.

  When the variation in the terminal voltage or the state of charge (SOC: State of Charge) of each unit cell C1 to CN becomes equal to or greater than a predetermined value between the unit cells C1 to CN, the capacity adjustment unit 504 On the basis of the capacity adjustment command, the opening / closing of each switch 402 provided in each capacity adjustment circuit 400 is controlled, whereby the capacity of the assembled battery 100 is adjusted.

The control unit 505 is a capacity adjustment unit based on the terminal voltage, charge / discharge current, and battery temperature data of each of the cells C1 to CN received from the voltage detection unit 501, the current detection unit 502, and the battery temperature detection unit 503. Capacitance adjustment control is performed to cause 504 to perform capacity adjustment. Specifically, the control unit 505 first sets a target equalization voltage V _tar that is a voltage for making the voltages of the individual cells C1 to CN constituting the assembled battery 100 uniform. The target equalization voltage V _tar is not particularly limited and can be set arbitrarily. For example, the lowest voltage among the voltages of the cells C1 to CN is set as the target equalization voltage V _tar . Alternatively, a predetermined voltage near the full charge of the assembled battery 100 or a predetermined voltage (for example, a full charge voltage or a predetermined voltage near the full charge voltage) is set in advance as the target equalization voltage V _tar. It may be set. The target equalization voltage V _tar set in this way is stored in a memory (not shown) provided in the battery controller 500. And the control part 505 calculates | requires the maximum voltage value and the minimum voltage value from the voltage between terminals of each cell C1-CN, and also calculates the voltage difference. When the voltage difference becomes equal to or greater than a preset voltage difference threshold value, the unit cells C1 to CN constituting the assembled battery 100 are uniformly supplied to the capacity adjustment unit 504 at the target equalization voltage _Vtar . A capacity adjustment command for performing control to obtain a correct voltage is generated, and the generated capacity adjustment command is sent to the capacity adjustment unit 504.

  Here, the voltage difference threshold corresponds to the magnitude of variation of each of the cells C1 to CN, and the variation condition becomes stricter by decreasing the threshold, and the variation condition becomes gradual by increasing the threshold. It is a threshold value. In this example, the voltage difference threshold value may be arbitrarily changed.

Then, the capacity adjustment unit 504 performs capacity adjustment by turning on the switches 402 of the cells C1 to CN to be adjusted during the adjustment time calculated by the actual measurement unit 509 described later based on the capacity adjustment command. Do. The voltage detector 501 detects the voltages of the cells C1 to CN even during capacity adjustment. Then, when the detected voltage of the cells C <b> 1 to CN during capacity adjustment reaches the target equalization voltage V _tar , the control unit 505 transmits a command to end the capacity adjustment to the capacity adjustment unit 504. The capacity adjustment unit 504 ends the capacity adjustment by turning off the switch 402 based on the command. The capacity adjustment unit 504 and the control unit 505 perform capacity adjustment in the same manner for other adjustment target batteries. Accordingly, the capacity adjustment unit 504 controls the on / off of each switch 402, thereby performing the control so that the voltages of the individual cells C1 to CN are uniform at the target equalization voltage _Vtar . Adjustments can be made. Alternatively, the capacity adjustment unit 504 performs capacity adjustment so that each of the single cells C1 to CN has a predetermined voltage by controlling on and off of each switch 402 based on the capacity adjustment command, and thereafter In the assembled battery 100, it is also possible to perform control such that the voltage of each of the single cells C1 to CN becomes uniform at the target equalization voltage V _tar by being repeatedly charged and discharged.

  In addition, the control unit 505 receives the data on the terminal voltage, charge / discharge current, and battery temperature of each of the cells C1 to CN received from the voltage detection unit 501, the current detection unit 502, and the battery temperature detection unit 503, and the abnormality determination unit. 506, to the prediction unit 507 and the actual measurement unit 509.

  The abnormality determination unit 506 is a determination unit that determines the type of abnormality of the assembled battery 100 using the actual measurement value calculated by the actual measurement unit 509 and the predicted value calculated by the prediction unit 507. An abnormality is determined after distinguishing between an abnormality caused by capacity deterioration, an abnormality caused by a short circuit in the assembled battery 100, and an abnormality caused by deterioration of the resistor 401. In addition, the control for abnormality determination of the assembled battery 100 in the abnormality determination part 506 is mentioned later.

  The predicting unit 507 adjusts the variation by the capacity adjusting unit 504 based on the voltage difference between the terminal voltages of the individual cells C1 to CN transmitted from the control unit 505, or per unit time by the capacity adjusting unit 504. The number of times of capacity adjustment is predicted as a predicted value. Note that the calculation control of the prediction value in the prediction unit 507 will be described later.

  The storage unit 508 is a memory that stores the voltage difference between the cells C1 to CN, the capacity adjustment time, and the detection time in association with each other. The storage unit 508 stores data that is referred to when the prediction unit 507 calculates a predicted value. In this example, in order for the prediction unit 507 to calculate a prediction value, data indicating the characteristics of the assembled battery 100 is continuously stored in the storage unit 508 as past data.

Found 509 by capacity adjustment unit 504, the calculation time in which capacity adjustment time of the voltage of each cell C1~CN until the targeted equalization voltage V _tar, or the adjustment number of times per unit time as a measured value To do. In the case of adjusting the capacity by discharging, the adjustment time for adjusting the capacity corresponds to the time for which each switch 402 is turned on. Since the on / off control of the switch 402 is controlled by the capacity adjustment unit 504, the actual measurement unit 509 measures the on-time of the switch 402 in the control of the capacity adjustment unit 504, thereby obtaining the actual capacity adjustment time. It can be calculated. The actual measurement unit 509 calculates the actual measurement value in time series by calculating the actual measurement value every time the capacity is adjusted.

Since the capacity adjustment time can be calculated from the detection voltage of each of the cells C1 to CN and the resistance value of the resistor 401, the actual measurement unit 509 adjusts the capacity by calculation using the detection voltage of each of the cells C1 to CN. You may calculate time. Also, when the capacity adjustment by charging and discharging, from the time of adjustment start, when the voltage of each cell C1~CN to calculating the time until the targeted equalization voltage V _tar, calculates the capacity adjustment time May be.

  When the abnormality determination unit 506 detects an abnormality in the assembled battery 100, the notification unit 510 notifies the abnormality of the assembled battery 100 by turning on a warning lamp (not shown) or the like. The communication unit 511 is a communication device that communicates the result of the abnormality determination of the assembled battery 100 determined by the abnormality determination unit 506 to the outside.

  Next, the control contents of the battery controller 500 will be described. First, prediction value calculation control by the prediction unit 507 will be described. The predicted value is an adjustment time corresponding to the ON time of the switch 402, the number of times of capacity adjustment per unit time, or an adjustment capacity. In the following description, the adjustment time will be described as a predicted value.

  As described above, the storage unit 508 stores the voltage difference between the detection voltages of the cells C1 to CN, the capacity adjustment time, and the detection time as past data. The voltage difference between the single cells C1 to CN, that is, the variation of the single cells C1 to CN increases as the deterioration of the battery proceeds. And the adjustment time which capacity | capacitance adjustment requires becomes long, so that the voltage difference between the single cells C1-CN is large.

  Here, the variation in voltage per unit time (change voltage per unit time) will be described. For voltage variation per unit time, the voltage difference between the cells C1 to CN at the time of adjustment is divided by the time from when there is no variation among the cells C1 to CN (immediately after capacity adjustment) to when the capacity adjustment is performed. It is calculated by doing. The voltage variation per unit time becomes larger as the battery deteriorates.

  As the variation per unit time increases, the adjustment time required for capacity adjustment also increases, so the adjustment time changes in a linear function with respect to the variation per unit time.

  The prediction unit 507 extracts measurement data from the latest data in time series to a predetermined number of data among the data stored in the storage unit 508, and each cell C1 to C1 included in the extracted measurement data. The voltage variation per unit time is calculated from the CN voltage difference and the detection time. Note that the voltage variation per unit time may be calculated by the prediction unit 507 when stored in the storage unit 508 and may be stored sequentially.

  The predicting unit 507 associates the voltage variation per unit time when the capacity adjustment is performed with the adjustment time when the capacity adjustment is performed, and then calculates the voltage variation per unit time on the x axis. Each data is plotted with the adjustment time as the y-axis. Next, a regression line as shown in FIG. 3 is obtained by performing linear regression on the obtained plot. Note that the method of linear regression is not particularly limited, and a least square method or the like may be used.

  And since the dispersion | variation in the voltage per unit time becomes large with progress of time, the adjustment time with respect to arbitrary future time can be estimated by extending the regression line shown in FIG. That is, the prediction unit 507 calculates the voltage difference between the cells C1 to CN in a predetermined cycle, and divides the voltage difference by the time from the current time to the previous capacity adjustment end time. The voltage variation is calculated. Then, using the adjustment time, the regression line of FIG. 3 is calculated, and the adjustment time corresponding to the voltage variation per unit time is extracted, whereby the predicted value is calculated in time series.

  As described above, in this example, the voltage variation of the cells C1 to CN and the adjustment time, which change due to battery deterioration, are stored in the storage unit 508 as past data, and a predicted value is calculated from the past data. When the assembled battery 100 is normal, the adjustment time actually performed by the capacity adjustment unit 504 later and the adjustment time related to the predicted value are substantially equal. On the other hand, when an abnormality occurs in the assembled battery 100, the actual adjustment time is different from the adjustment time related to the predicted value. Therefore, in this example, the abnormality of the assembled battery 100 is detected using the predicted value and the actually measured value.

  Next, control for determining abnormality of the assembled battery 100 will be described. The abnormality determination unit 506 reads, via the control unit 505, the adjustment time that is the actual measurement value calculated by the actual measurement unit 509 and the adjustment time that is the prediction value calculated by the prediction unit 507. Then, the abnormality determination unit 506 calculates the divergence of the actual measurement value with respect to the predicted value by calculating the difference between the actual measurement value and the predicted value. When the measured value and the predicted value are the same value, the divergence degree is zero.

  Here, the relationship between the actually measured value and the predicted value and the type of abnormality of the assembled battery 100 will be described with reference to FIG. FIG. 4 is a graph showing characteristics of actual measurement values and prediction values with respect to time. Graphs a and b in FIG. 4 are characteristics of actual measurement values, and a graph c is a graph indicating characteristics of predicted values. As shown in FIG. 4, the prediction unit 507 and the actual measurement unit 509 calculate the predicted value and the actual measurement value in time series, respectively. The actual measurement value changes with a different waveform depending on the type of abnormality of the assembled battery 100 with respect to the predicted value.

  A case where the actual measurement value is smaller than the predicted value as shown in graph a of FIG. 4 will be described. When the actual measurement value is smaller than the predicted value, the battery pack 100 is abnormal because the capacity of the battery pack 100 has deteriorated.

FIG. 5 is a graph showing voltage characteristics with respect to the capacities of the single cells C <b> 1 to CN included in the assembled battery 100. The graph a in FIG. 5 shows the characteristics before deterioration, and the graph b shows the characteristics after deterioration. As shown in the graph b, when the cells C1 to CN are deteriorated, the capacity with respect to the voltage is reduced. Voltage differential fully charged when the voltage ([Delta] V) content, adjusting capacity required for lowering the voltage (discharge capacity) of .DELTA.Ah 1 _(before deterioration), when .DELTA.Ah 2 _(after deterioration), after degradation .DELTA.Ah ₂ Becomes smaller than ΔAh ₁ before deterioration. That is, as the capacity deterioration progresses, the electric capacity necessary for capacity adjustment becomes smaller, so the adjustment time becomes shorter and the actual measurement value becomes smaller.

  Therefore, as shown in the graph a of FIG. 4, the fact that the measured value is smaller than the predicted value indicates that an abnormality has occurred due to the capacity deterioration of the assembled battery 100. Further, since the capacity deterioration progresses with time, as shown in FIG. 4, the difference between the actual measurement value and the predicted value increases with time.

  A case where the actual measurement value is larger than the predicted value as shown in the graph b of FIG. 4 will be described. When the measured value is larger than the predicted value, the battery pack 100 is abnormal due to a minute short circuit in the battery pack 100, deterioration of the internal resistance of the battery pack 100, or deterioration of the resistor 401. Has occurred.

  FIG. 6 is a graph showing voltage characteristics with respect to the capacity of the assembled battery 100. Graph a in FIG. 6 shows the characteristics of a battery in which a micro short circuit has not occurred, and graph b shows the characteristics of a battery in which a micro short circuit has occurred. As shown in the graph b, when a micro short circuit occurs, the voltage with respect to the full charge capacity does not drop, but as the capacity becomes smaller, the voltage with the short circuit becomes lower than the voltage without the short circuit. If the adjustment capacity is the same, the voltage drop due to the adjustment of the battery in which the micro short circuit has occurred is larger than the voltage drop due to the adjustment of the battery in which the micro short circuit has not occurred. In addition, when the voltage difference is the same, the adjustment capacity of the battery with the micro short circuit is larger than the adjustment capacity of the battery without the micro short circuit, and the adjustment time is similarly longer. growing. Therefore, the fact that the actual measurement value is larger than the predicted value indicates that an abnormality has occurred due to a minute short circuit in the assembled battery 100.

  FIG. 7 is a circuit diagram simply showing a connection circuit between the cells C1 to CN and the resistor 401 in this example. As shown in FIG. 7, the resistance value of the internal resistance of the unit cell Cp is r, the resistor R, and the output current of the unit cell Cp is i. The unit cell Cp indicates any unit cell included in the unit cells C1 to CN.

First, deterioration of the resistor 401 will be described. When the resistance 401 deteriorates, the resistance value (R) increases. When the inter-terminal voltage of the cell Cp is E ₀ and the internal resistance is r, the output current (i) of the cell Cp is calculated from i = E ₀ / (r + R). When the resistance value (R) increases due to deterioration of the resistor 401, the output current (i) of the unit cell Cp decreases. When capacity adjustment is performed with the deteriorated resistor 401, the current (i) of the unit cell Cp discharged for adjustment becomes small, and the time for outputting the current for capacity adjustment becomes long. Since the adjustment time when the deterioration of the resistor 401 advances is longer than the adjustment time when the deterioration of the resistor 401 does not advance, the actual measurement value becomes larger than the predicted value. Therefore, the fact that the actually measured value is larger than the predicted value indicates that an abnormality has occurred due to the deterioration of the resistor 401.

  Next, deterioration of the internal resistance of the cells C1 to CN will be described with reference to FIG. When the internal resistance of the unit cell Cp deteriorates, the resistance value (r) increases. When the resistance value (r) increases due to the deterioration of the internal resistance, the output current (i) of the unit cell Cp decreases, so the adjustment time when the deterioration of the internal resistance has progressed is when the deterioration of the internal resistance has not progressed It becomes longer compared with the adjustment time. Therefore, the adjustment time when the deterioration of the internal resistance proceeds is longer than the adjustment time when the deterioration of the internal resistance is not advanced, and the actual measurement value becomes larger than the predicted value.

  Therefore, the fact that the actual measurement value is larger than the predicted value indicates that an abnormality has occurred due to the deterioration of the internal resistance of the cells C1 to CN. Further, since the deterioration of the resistor 401 and the deterioration of the internal resistances of the cells C1 to CN progress with time, as shown in FIG. 4, the difference between the actually measured value and the predicted value becomes larger with time.

  When the actual measurement value is larger than the expected value, the abnormality determination unit 506 is caused by a minute short circuit in the assembled battery 100, deterioration of the internal resistance of the cells C1 to CN included in the assembled battery 100, or deterioration of the resistor 401. If it is determined that an abnormality has occurred and the actual measurement value is smaller than the predicted value, it is determined that an abnormality has occurred due to the deterioration of the capacity of the assembled battery 100.

  In this example, the abnormality determination unit 506 may determine from the positive / negative of the degree of deviation when determining the magnitude relationship between the actual value and the predicted value using the degree of deviation of the actual value with respect to the predicted value. That is, the value obtained by subtracting the predicted value from the actual measurement value is defined as the divergence degree. When the divergence degree is positive, the actual measurement value is larger than the expected value, and when the divergence degree is negative, the actual measurement value is smaller than the predicted value. . The abnormality determination unit 506 calculates the divergence degree in time series.

  The characteristics shown in FIG. 4 are represented as shown in FIG. FIG. 8 is a graph showing the time characteristic of the divergence. Graph a in FIG. 8 corresponds to graph a in FIG. 4 and graph b in FIG. 8 corresponds to graph b in FIG.

  Then, the abnormality determination unit 506 determines that an abnormality has occurred in the assembled battery 100 when the magnitude (absolute value) of the divergence degree is larger than a determination threshold value for abnormality determination. That is, the predicted value is derived from the past voltage difference data as described above, and is merely an estimated value based on the past data. The predicted value is a value that varies depending on the degree of deterioration of the assembled battery 100, manufacturing variations, and the like. Therefore, even when no abnormality has occurred in the assembled battery 100, the actual measurement value and the predicted value may not completely match. Therefore, in this example, by setting a determination threshold value that is not zero, when determining an abnormality in the assembled battery 100 based on a change in the actual measurement value with respect to the predicted value, the predicted value has a width to prevent erroneous detection.

  That is, the abnormality determination unit 506, when the degree of divergence is larger than the threshold value and the degree of divergence is positive, the micro short circuit in the assembled battery 100, the inside of the cells C1 to CN included in the assembled battery 100 When it is determined that an abnormality has occurred due to the deterioration of the resistance or the deterioration of the resistance 401 and the magnitude of the divergence is larger than the threshold and the divergence is negative, the capacity of the assembled battery 100 is deteriorated. It is determined that an abnormality has occurred.

  Next, the control processing procedure of the controller 500 will be described with reference to FIG. FIG. 9 is a flowchart showing a control procedure of the controller 500. Note that the control loop shown in FIG. 9 is repeatedly performed unless it is determined that the assembled battery 100 is abnormal.

  In step S1, voltage detection unit 501 detects the terminal voltages of single cells C1 to CN at a predetermined cycle. In step S <b> 2, the control unit 505 identifies the maximum voltage and the minimum voltage from the detection voltages of the individual cells C <b> 1 to CN, and takes the difference between the maximum voltage and the minimum voltage to obtain a voltage difference (ΔV). Is calculated.

  In step S3, the control unit 505 compares the voltage difference (ΔV) with a voltage difference threshold value. If the voltage difference (ΔV) is less than the voltage difference threshold value, it is determined that there is no variation between the cells C1 to CN, and the process returns to step S1. On the other hand, if the voltage difference (ΔV) is greater than or equal to the voltage difference threshold, in step S4, the control unit 505 transmits a capacity adjustment command to the capacity adjustment unit 504, and the capacity adjustment unit 504 switches the switch based on the command. 402 is turned on to adjust the capacity.

In step S <b> 5, the capacity adjustment unit 504 determines whether or not the voltages of all the cells C <b> 1 to CN that have been subjected to capacity adjustment have reached the target equalization voltage V _tar from the detection voltage of the voltage detection unit 501. Thus, it is determined whether or not the capacity adjustment is completed. When the capacity adjustment is not completed, the capacity adjustment control by the capacity adjustment unit 504 is continued. When the capacity adjustment is completed, the process proceeds to step S6.

  In step S6, the prediction unit 507 calculates a predicted value at the start of capacity adjustment in step S4, and an actual value 509 calculates an actual value in capacity adjustment control in steps S4 and S5.

  First, the prediction unit 507 uses the time from the completion of the previous capacity adjustment to the start of the current capacity adjustment and the voltage difference at the start of the current capacity adjustment (corresponding to the voltage difference (ΔV) in step S2). Thus, the variation in voltage per unit time (the amount of change in voltage difference per unit time) is calculated. Further, the prediction unit 507 calculates a regression line from the past data stored in the storage unit 508 by performing a linear regression operation on the characteristics of the adjustment time with respect to the variation in voltage per unit time. Then, the prediction unit 507 calculates an adjustment time corresponding to the predicted value using the calculated voltage variation per unit time and the regression line.

  In step S <b> 7, the abnormality determination unit 506 calculates the degree of divergence by subtracting the predicted value calculated by the prediction unit 507 from the actual value calculated by the actual value 509. Then, the abnormality determination unit 506 compares the absolute value of the divergence degree with a determination threshold value. If the absolute value of the divergence degree is lower than the determination threshold, the abnormality determination unit 506 determines that no abnormality has occurred in the assembled battery 100 in step S11, and the control process ends.

  Returning to step S7, if the absolute value of the divergence degree is greater than or equal to the determination threshold value, it is determined in step S8 whether the divergence degree is greater than zero or not. When the divergence degree is 0 or less, that is, when the divergence degree is negative, the actual measurement value is smaller than the predicted value. Therefore, in step S <b> 9, the abnormality determination unit 506 generates a micro short-circuit in the assembled battery 100. The controller 505 determines that an abnormality has occurred due to the deterioration of the internal resistance of the assembled battery 100 or the deterioration of the resistor 401, and the control unit 505 notifies the user of the abnormality by controlling the notification unit 510, thereby controlling the present example. finish.

  On the other hand, when the degree of divergence is greater than zero, that is, when the degree of divergence is positive, the actual measurement value is larger than the predicted value. Therefore, in step S10, the abnormality determination unit 506 causes the capacity degradation of the assembled battery 100 to occur. The controller 505 determines that an abnormality has occurred, controls the notification unit 510 to notify the user of the abnormality, and ends the control of this example.

  As described above, the present invention includes a capacity adjustment unit 504 that adjusts the variation of the cells C1 to CN, a prediction unit 507 that calculates a predicted value from the voltage difference between the cells C1 to CN, and an actual capacity adjustment. An actual measurement unit 509 that calculates the adjustment time as an actual measurement value, and an abnormality determination unit 506 that determines the type of abnormality of the assembled battery 100 using the predicted value and the actual measurement value. Thus, by using both the predicted value and the actual measurement value for detecting the abnormality of the assembled battery 100, it is possible to detect the difference in the actual value change with respect to the predicted value, and thus distinguish the type of abnormality of the assembled battery 100. In addition, an abnormality can be determined.

  In the present invention, the abnormality determination unit 506 calculates the divergence degree of the actual measurement value with respect to the predicted value, and determines the type of abnormality of the assembled battery 100 according to the divergence degree. The type of abnormality of the assembled battery 100 differs depending on how the actual measurement value changes with respect to the predicted value. However, since this example calculates the divergence degree, a change in divergence degree (positive or negative change) is detected. As a result, the abnormality determination can be performed after distinguishing the type of abnormality of the assembled battery 100. Furthermore, since the change in the degree of divergence (positive or negative change) distinguishes the capacity deterioration of the assembled battery 100 from the deterioration of the internal resistance of the assembled battery 100 and the deterioration of the resistor 401, this example shows the deterioration of the assembled battery 100. Abnormality of the assembled battery 100 can be determined after distinguishing the types.

  Further, in this example, when the actual measurement value is larger than the predicted value, the abnormality determination unit 506 causes the assembled battery 100 due to deterioration of the internal resistance of the assembled battery 100, a minute short circuit within the assembled battery 100, or deterioration of the resistor 401. It is determined that an abnormality has occurred. Thereby, this example can determine the abnormality of the assembled battery 100, after specifying the cause of abnormality of the assembled battery 100.

  Further, in this example, the abnormality determination unit 506 determines that an abnormality has occurred in the assembled battery 100 due to capacity deterioration of the assembled battery 100 when the actually measured value is smaller than the predicted value. Thereby, this example can determine the abnormality of the assembled battery 100, after specifying the cause of abnormality of the assembled battery 100.

  Further, in this example, the abnormality determination unit 506 determines that an abnormality has occurred in the assembled battery 100 when the magnitude (absolute value) of the divergence degree is larger than a determination threshold value for abnormality determination. In other words, the abnormality determination unit 506 determines that an abnormality has occurred in the assembled battery 100 when the actually measured value is outside a predetermined range including the expected value (corresponding to the determination threshold). Thereby, when the measured value deviates from the range of the predicted value, it can be determined that an abnormality has occurred in the assembled battery 100, and the accuracy of the abnormality determination can be increased.

  Further, in this example, the notification unit 510 notifies the abnormality of the assembled battery 100. Thereby, the user can confirm the abnormality of the assembled battery 100. When an abnormality occurs in the assembled battery 100, the notification unit 510 notifies the abnormality of the assembled battery 100 and the type of abnormality to the outside such as the center via the communication unit 511, so that the same as the assembled battery 100. The possibility of future abnormality in the battery can be alerted.

  In this example, the abnormality determination unit 506 calculates the difference between the predicted value and the actual measurement value (corresponding to the degree of divergence) in time series, and the difference calculated at a predetermined time is calculated before the predetermined time. It may be determined that an abnormality has occurred in the battery pack 100 when the difference calculated is greater than the difference. The deterioration of the assembled battery 100, the deterioration of the internal resistance in the assembled battery 100, or the deterioration of the resistor 401 gradually proceeds with time. And the progress of these deteriorations appears as the difference between the predicted value and the measured value gradually increases. Further, as described above, since the type of deterioration can be distinguished from the magnitude relationship between the predicted value and the actually measured value, the divergence direction of the difference between the predicted value and the actually measured value, in other words, the actually measured value for the predicted value. By detecting whether the value is gradually increased or gradually decreased, the tendency of abnormality of the assembled battery 100 can be determined while distinguishing the type of abnormality.

  Therefore, in this example, the abnormality determination unit 506 calculates the divergence degree in time series, and if the divergence degree at the predetermined time is larger than the divergence degree calculated before the predetermined time, the abnormality determination unit 506 It is determined that an abnormality has occurred. Thereby, at the time when the divergence degree expansion tendency is detected, it is possible to determine the abnormality after distinguishing the type of abnormality of the assembled battery 100 from the deviation direction of the actual measurement value with respect to the predicted value.

  In this example, the abnormality determination unit 506 determines that the abnormality determination is performed when the amount of change in the predicted value per unit time is larger than a predetermined amount of change (corresponding to the “third change amount” of the present invention). Is prohibited. The predicted value calculated by the predicted value 507 is a value calculated from past data stored in the storage unit 508, and is merely an expected value. Therefore, when the predicted value changes suddenly, the calculated value of the predicted value 507 may not be accurate. Furthermore, when the predicted value fluctuates rapidly, but the measured value does not fluctuate abruptly, there is a higher possibility that the calculated value of the predicted value 507 is not accurate.

  Therefore, in this example, the abnormality determination unit 506 determines that the change amount of the predicted value per unit time is larger than the predetermined change amount, or the change amount of the predicted value per unit time is larger than the predetermined change amount. In addition, when the amount of change in the actual measurement value per unit time is smaller than the predetermined amount of change, the determination of abnormality of the assembled battery 100 is prohibited. Thus, in this example, when the prediction unit 507 calculates a predicted value with low reliability, it is possible to prevent the abnormality of the assembled battery 100 from being erroneously determined using the predicted value.

  In this example, the prediction unit 507 may calculate the predicted value using information regarding the other assembled battery 100 received by the communication unit 511. The prediction unit 507 calculates a predicted value from the data of the past assembled battery 100, but acquires data corresponding to the past data from a vehicle equipped with a battery similar to the assembled battery 100 via the communication unit 511.

  For example, in another vehicle, data related to the assembled battery 100 has already been acquired and accumulated in a database of a center that manages the other vehicle. When the assembled battery 100 is used in the own vehicle, past data of the assembled battery 100 is stored. Is not stored in the storage unit 508. In such a case, since the prediction unit 507 cannot use the data in the storage unit 508, the past data for calculating the predicted value is acquired from the center via the communication unit 511. And the prediction part 507 calculates a regression line using the data received with the communication part 511 similarly to the above, and calculates a predicted value.

  Thereby, since this example can calculate a predicted value using not only the data of the assembled battery 100 of the own vehicle but also the data of the assembled battery 100 of another vehicle, the calculation accuracy of the predicted value can be improved. .

  In this example, the prediction unit 507 calculates the capacity adjustment time as the predicted value, but may calculate the number of capacity adjustments per unit time as the predicted value. The number of times of capacity adjustment is, for example, the time of adjustment, the number of times the switch 402 is turned on and off is stored in the storage unit 508, and the prediction unit 507 adjusts per unit time from these data stored in the storage unit 508. Calculate the number of times.

  The prediction unit 507 calculates the variation in voltage per unit time in the same manner as described above. When the variation in voltage per unit time increases, the time from when there is no variation (state after capacity adjustment) until the voltage difference between the cells C1 to CN reaches the voltage difference threshold is shortened. The number of times also increases. The number of times of capacity adjustment per unit time changes in a linear function with respect to variation per unit time.

  The predicting unit 507 refers to the data in the storage unit 508, associates the voltage variation per unit time with the number of capacity adjustments per unit time, and sets the voltage variation per unit time as the x-axis. Each data is plotted with y as the y-axis. Next, a regression line is obtained by performing linear regression on the obtained plot. And since the voltage variation per unit time becomes large with progress of time, the frequency | count of adjustment with respect to arbitrary future time can be estimated by extending the said regression line.

  When the prediction unit 507 uses the number of adjustments per unit time as a predicted value, the actual measurement unit 509 uses the number of adjustments per unit time actually adjusted by the capacity adjustment unit as the actual measurement value instead of the adjustment time. Calculate. Then, the abnormality determination unit 506 uses the number of adjustments per unit time calculated by the prediction unit 507 and the number of adjustments per unit time calculated by the actual measurement unit 509 in the same manner as described above. What is necessary is just to perform abnormality determination and abnormality type determination.

  In this example, when the absolute value of the divergence degree is equal to or greater than the determination threshold value and the divergence degree is a positive value, the abnormality determination unit 506 generates a micro short-circuit in the assembled battery 100, or the assembled battery 100. It is determined that an abnormality has occurred due to the deterioration of the internal resistance of the battery or the deterioration of the resistance 401. However, using the amount of change in the actual measurement value, the short-circuit in the battery pack 100 and the internal resistance of the battery pack 100 After distinguishing the deterioration and the deterioration of the resistor 401, the battery pack 100 or more may be determined.

  That is, the deterioration of the internal resistance of the assembled battery 100 and the deterioration of the resistance 401 gradually progress, but a micro short circuit occurs in the short term. For this reason, the amount of change in the short-term change in the actually measured value is greater than the amount of change due to resistance deterioration when a micro short circuit occurs. When the micro short circuit occurs, the magnitude of the actually measured value that changes is determined in advance by the cells C <b> 1 to CN incorporated in the assembled battery 100. Therefore, a threshold value for determining a minute short circuit can be set in advance.

  Therefore, the abnormality determination unit 506 compares the amount of change of the measured value per unit time with the threshold value in the process of step S9 of FIG. 9, and if the amount of change is larger than the threshold value, the abnormality determination unit 506 When it is determined that an abnormality of the assembled battery 100 has occurred due to a micro short-circuit, and the amount of change is smaller than the threshold value, the abnormality of the assembled battery 100 has occurred due to deterioration of the internal resistance of the assembled battery 100 or deterioration of the resistor 401. judge. Thereby, this example can detect abnormality of a battery, after subdividing the kind of abnormality of assembled battery 100 further.

  In this example, the control unit 505 may use the temperature detected by the temperature sensor 102 when determining the variation in capacity using the SOCs of the cells C1 to CN. The SOC of the single cells C1 to CN and the detection voltage of the single cells C1 to CN have a correlation as shown in FIG. 6, but the correlation has temperature dependency. Then, how the voltage-SOC curve of FIG. 6 changes with respect to the battery temperature is determined in advance according to the characteristics of the battery. Therefore, the control unit 505 calculates the SOC by referring to the curve from the detected temperatures of the cells C1 to CN, calculating the corresponding SOC, and correcting according to the temperature sensor 102.

  In this example, the resistance value of the resistor 401 is a fixed value, but the resistor 401 may be a variable resistor. In addition, when the resistor 401 is a variable resistor, the prediction unit 507 and the actual measurement unit 509 use the battery adjustment capacity (charge / discharge) until the variation of the cells C1 to CN is adjusted instead of the adjustment time and the number of adjustments. Capacity). The adjustment capacity corresponds to the difference between the capacity of the battery before capacity adjustment and the capacity of the battery after capacity adjustment.

  The control unit 505 sets the resistance value of the resistor 401 when the capacitance adjustment unit 504 performs capacitance adjustment. Further, the control unit 505 calculates the integrated value of the charge / discharge current being adjusted by integrating the detection current of the current sensor 102 during capacity adjustment. Then, the control unit 505 can calculate the adjustment capacity from the integrated value and the set resistance value.

  The control unit 505 stores the calculated adjustment capacity in the storage unit 508 as past data. Then, the prediction unit 507 calculates a regression line as a predicted value after calculating a regression line using the past data in the storage unit 508 in the same manner as described above. The actual measurement unit 509 uses the adjustment capacity calculated by the control unit 505 as an actual measurement value.

  Accordingly, in this example, the adjustment capacity of the cells C1 to CN is calculated as the predicted value and the actual measurement value by the prediction unit 507 and the actual measurement unit 509, respectively, and using the predicted value and the actual measurement value, Determine the type of abnormality. The resistance for capacity adjustment may be a resistance of an external circuit of the assembled battery system.

  The voltage detection unit 501 corresponds to the “voltage detection unit” of the present invention, the capacity adjustment unit 504 is the “capacity adjustment unit” of the present invention, the prediction unit 507 is the “predicted value calculation unit”, and the actual measurement unit 509 is In the “actual value calculation means”, the abnormality determination unit 506 corresponds to “determination means”, the notification unit 510 corresponds to “notification unit”, and the communication unit 511 corresponds to “communication unit”.

<< Second Embodiment >>
FIG. 10 is a graph showing the characteristic of the degree of deviation with respect to time in the battery pack control apparatus according to another embodiment of the invention. In this example, part of the abnormality determination control of the battery pack 100 is different from the first embodiment described above. Since the configuration other than this is the same as that of the first embodiment described above, the description thereof is incorporated as appropriate.

  The abnormality determination unit 506 calculates a divergence degree in time series from the difference between the predicted value of the prediction unit 507 and the actual measurement value of the actual measurement unit 509. The abnormality determination unit 506 calculates the amount of change in the deviation degree per unit time. The abnormality determination unit 506 detects whether the sign of the divergence degree is reversed. When the positive / negative of the opening degree is reversed, the abnormality determination unit 506 calculates the amount of change per unit time from the amount of change in the divergence degree before and after the reversal, and compares the amount of change per unit time with the change amount threshold value. To do. The change amount threshold value is a threshold value set in advance, and is a threshold value for determining an abnormality of the assembled battery 100. Then, the abnormality determination unit 506 causes the abnormality of the assembled battery 100 due to a short circuit abnormality in the assembled battery 100 when the degree of deviation is reversed from negative to positive and the variation amount per unit time is larger than the variation amount threshold value. It is determined that it has occurred.

A case where a minute short-circuit suddenly occurs at the time t _{0 in} a situation where the capacity deterioration of the assembled battery 100 is progressing with time will be described. Before the minute short circuit occurs, the actual measurement value becomes smaller than the predicted value due to the capacity deterioration of the assembled battery 100. Therefore, as shown in FIG. 10, the degree of divergence becomes a negative value and gradually decreases with time. . When a short circuit occurs at the time t ₀ , the actual measurement value exceeds the predicted value and becomes large. That is, the time of t ₀ is a change point, the change amount per unit time of t ₀ and subsequent, t ₀ is larger than the amount of change per previous unit time.

  Therefore, in this example, the abnormality determination unit 506 detects the degree of divergence in time series, thereby determining the magnitude relationship between the predicted value and the actual measurement value, and the amount of change in the difference between the predicted value and the actual measurement value per unit time. Is detected. Then, the abnormality determination unit 506 reverses the magnitude relationship between the predicted value and the actually measured value, and the change amount of the difference between the predicted value and the actually measured value per unit time is the change amount threshold (the “second change of the present invention”). It is determined that an abnormality of the assembled battery 100 has occurred.

  As described above, in this example, the abnormality determination unit 506 reverses the magnitude relationship between the predicted value and the actually measured value, and the change amount of the difference between the predicted value per unit time and the actually measured value is the change amount threshold (from If it is larger, it is determined that an abnormality has occurred in the assembled battery 100. Thus, in this example, a change in the actual measurement value with respect to the predicted value is detected in time series, so that the abnormality occurring in the assembled battery 100 is detected. The type can be determined.

  Further, in this example, the abnormality determination unit 506 performs a micro short circuit in the assembled battery 100 when the divergence degree is reversed from negative to positive and the change amount of the divergence degree per unit time is larger than the change amount threshold value. It is determined that an abnormality of the assembled battery 100 has occurred. Thereby, this example can determine the kind of abnormality, after specifying a micro short circuit among the kinds of abnormality which has arisen in the assembled battery 100. FIG.

  In this example, the type of abnormality is determined based on the positive / negative change point of the divergence degree and the change amount of the divergence degree per unit time. However, the abnormality determination unit 506 determines the change amount of the divergence degree per unit time. If it is larger than the change amount threshold (corresponding to the “first change amount” of the present invention), it may be determined that an abnormality has occurred in the battery pack 100.

  Unlike a capacity deterioration or a resistance deterioration, a micro short circuit may occur suddenly, and may occur even in the case of a battery in which deterioration has not progressed relatively. Therefore, by determining as described above, in this example, the deterioration of the assembled battery 100 is not progressing, and the type of abnormality can be determined after specifying a micro short circuit that has occurred with a low degree of divergence. it can.

DESCRIPTION OF SYMBOLS 100 ... Assembly battery C1-CN, Cp ... Single cell 102 ... Temperature sensor 200 ... Load 300 ... Current sensor 400 ... Capacity adjustment circuit 401 ... Resistance 402 ... Switch 500 ... Battery controller 501 ... Voltage detection part 502 ... Current detection part 503 ... Battery temperature detection unit 504 ... capacity adjustment unit 505 ... control unit 506 ... abnormality determination unit 507 ... prediction unit 508 ... storage unit 509 ... measurement unit 510 ... notification unit 511 ... communication unit

Claims (11)

A battery pack control device comprising a battery pack including a plurality of battery cells and a voltage detection means for detecting a voltage value of the battery cell,
Adjusting means for adjusting the voltage or state of charge of the plurality of single cells to a predetermined target value;
Adjustment time for adjusting variations in voltage or charging state of the plurality of single cells by the adjusting means, adjustment frequency per unit time by the adjusting means, or voltage or charging of the plurality of single cells by the adjusting means Predicted value calculation means for predicting the adjustment capacity of the plurality of single cells for adjusting the state variation as a predicted value from a voltage difference of the voltage values between the plurality of single cells;
Using the adjustment means, the adjustment time actually required until the voltage or state of charge of the plurality of single cells is adjusted to the target value, or per unit time actually adjusted using the adjustment means The number of adjustments, or the adjustment capacity that is actually adjusted using the adjustment means, as an actual measurement value calculation means,
An assembled battery control device comprising: a determination unit that determines a type of abnormality of the assembled battery using the predicted value and the actually measured value. The determination means includes
The assembled battery control device according to claim 1, wherein a deviation degree of the actual measurement value with respect to the predicted value is calculated, and an abnormality type of the assembled battery is determined according to the deviation degree. The determination means includes
When the actual measurement value is larger than the predicted value, the battery pack may be deteriorated due to deterioration of internal resistance of the battery pack, micro short circuit in the battery pack, or deterioration of adjustment resistance included in the adjustment unit. 3. The assembled battery control device according to claim 1, wherein it is determined that an abnormality has occurred. The determination means includes
4. The method according to claim 1, wherein when the actually measured value is smaller than the predicted value, it is determined that an abnormality of the assembled battery has occurred due to deterioration of the capacity of the assembled battery. The control apparatus of the assembled battery as described. The determination means includes
Calculate the difference between the predicted value and the measured value in time series,
2. The battery pack according to claim 1, wherein when the difference calculated at a predetermined time is larger than the difference calculated at a time before the predetermined time, it is determined that an abnormality has occurred in the assembled battery. The control apparatus of the assembled battery as described in any one of -4. The determination means includes
Calculate the difference between the predicted value and the measured value in time series,
5. The battery pack according to claim 1, wherein when the amount of change in the difference per unit time is larger than a first change amount indicating an abnormality of the assembled battery, it is determined that an abnormality has occurred in the assembled battery. The assembled battery control device according to claim 1. The determination means includes
Calculate the difference between the predicted value and the measured value in time series,
An abnormality occurs in the assembled battery when the magnitude relationship between the predicted value and the actually measured value is reversed and the change amount of the difference per unit time is larger than a second change amount indicating an abnormality of the assembled battery. The battery pack control apparatus according to claim 1, wherein the battery pack control apparatus determines that the battery pack has The determination means includes
2. The determination of abnormality of the assembled battery is prohibited when the amount of change of the predicted value per unit time is larger than a third amount of change indicating a criterion for determining abnormality of the assembled battery. The control apparatus of the assembled battery as described in any one of -7. The determination means includes
9. The battery pack according to claim 1, wherein when the actual measurement value is outside a predetermined range including the predicted value, it is determined that an abnormality of the assembled battery has occurred. Control device for battery pack. It further includes a communication unit that communicates with the outside,
The predicted value calculation means includes:
The assembled battery control device according to any one of claims 1 to 9, wherein the predicted value is calculated using information on the assembled battery received by the communication unit. The control device for an assembled battery according to any one of claims 1 to 10, further comprising notification means for notifying the abnormality of the assembled battery.

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