JP2017200313A - Method for controlling charging/discharging of assembled battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a current flowing through a disconnected cell when the disconnected cell of the cell block reconducts.SOLUTION: When there are normal cell blocks 30, 40, 50 in which all cells 31, 41, 51 are connected in parallel by the parallel connection line and a disconnected cell block 20a including a disconnected cell 21a in which a negative connection bus bar 26 is disconnected, on the basis of reduction in a voltage difference (| ΔOCV |) between an OCV of the normal cell block 30, 40, 50 and an OCV of the disconnected cell block 20a when charging/discharging an assembled battery 10, an SOC of the disconnected cell 21a is estimated and the assembled battery 10 is charged/discharged so that the SOC of the assembled battery 10 becomes a predetermined control range Ws around the estimated SOC of the disconnected cell 21a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an assembled battery, and more particularly to a charge / discharge control method for an assembled battery in which cell blocks in which a plurality of cells are connected in parallel are connected in series.

  In recent years, an assembled battery in which cell blocks in which a plurality of cells are connected in parallel is connected in series has been used as a battery for supplying electric power to a drive motor of an electric vehicle. In such an assembled battery, the connection line which connects each cell in parallel may be disconnected. For this reason, an apparatus for detecting disconnection of a connection line connecting cells in parallel has been proposed (see, for example, Patent Document 1).

JP 2009-216448 A

  By the way, if the connection line connecting the cells of the cell block in parallel is disconnected, the cell in which the connection line is disconnected (hereinafter referred to as disconnected cell) cannot be charged / discharged, so the charge rate of the disconnected cell (hereinafter referred to as SOC) is The SOC is maintained when the connection line is disconnected. On the other hand, the SOC of normal cells other than the disconnected cell changes due to charging / discharging of the entire assembled battery. For example, even when the SOC of a disconnected cell is maintained at 50%, the SOC of a normal cell changes within a range of 20% to 90%.

  A connection line connecting the cells of the cell block in parallel is a thin metal plate bent and connected to each cell by resistance welding to the surface of the positive electrode or the negative electrode of each cell. After the connection lines are disconnected due to vibration of the electric vehicle or the like, sparks are generated when the connection lines disconnected due to vibration or the like of the electric vehicle come into contact with each other. Thereby, the connection lines that have been disconnected may be welded together, and the disconnected cell may re-conduct. When the SOC when the disconnected cell is re-conducted is lower than the SOC of the normal cell, a large current flows from the normal cell toward the disconnected cell during the re-conduction. On the other hand, when the SOC when the disconnected cell is re-conducted is higher than the SOC of the normal cell, a large current flows from the disconnected cell toward the normal cell during the re-conduction. For this reason, when the disconnected cell is re-conducted, the temperature of the disconnected cell or the surrounding normal cell rises, and the assembled battery may deteriorate.

  Accordingly, an object of the present invention is to suppress a current flowing through a disconnected cell when the disconnected cell of the cell block is re-conducted.

  The battery pack charge / discharge control method of the present invention is a battery pack charge / discharge control method in which a plurality of cells connected in parallel are connected in series, and all the cells are connected in parallel by parallel connection lines. A normal cell block, and a disconnected cell block including a disconnected cell in which a parallel connection line is disconnected, and a first open voltage and the disconnected cell block of the normal cell block when the assembled battery is charged / discharged Based on the reduction of the voltage difference with the second open circuit voltage, the charging rate of the disconnected cell is estimated, and the charging rate of the assembled battery is within a predetermined control range centered on the estimated charging rate of the disconnected cell. And charging and discharging the assembled battery.

  The present invention can suppress a current flowing through a disconnected cell when a disconnected cell of the cell block is re-conducted.

1 is a system diagram illustrating a configuration of an electric vehicle to which a charge / discharge control method according to an embodiment of the present invention is applied. It is a top view which shows the parallel bus bar and connection bus bar of the positive electrode of the cell block which comprise the assembled battery shown in FIG. It is a top view which shows the parallel bus bar and connection bus bar of the negative electrode of the cell block which comprise the assembled battery shown in FIG. It is a sectional side view of the cell block which comprises the assembled battery shown in FIG. It is explanatory drawing which shows the driving mode of an electric vehicle shown in FIG. 1, and the change of SOC of a battery pack, a cell block, and a cell. It is explanatory drawing which shows the cutting | disconnection and re-conduction of a negative electrode connection bus bar. It is explanatory drawing which shows the change of SOC of each cell in a cell block, and an electric current at the time of reconducting when SOC of a disconnection cell is lower than SOC of a normal cell. It is explanatory drawing which shows the change of SOC of each cell in a cell block, and an electric current when re-conduction occurs when SOC of a disconnection cell is higher than SOC of a normal cell. It is a figure which shows the open circuit voltage characteristic of a normal cell block and a disconnection cell block. It is a flowchart which shows the charge control method of this embodiment. It is a graph which shows the change of the open circuit voltage of a disconnection cell block with respect to SOC of a normal cell block at the time of performing charge / discharge control of an assembled battery by the charge control method shown in FIG. It is explanatory drawing which shows the change of SOC of each cell in a disconnection cell block at the time of performing charging / discharging control of an assembled battery by the charge control method shown in FIG. It is a flowchart which shows the charge control method of this embodiment in the case of EV driving | running | working. It is a graph which shows the change of the open circuit voltage of a disconnection cell block with respect to SOC of a normal cell block at the time of performing charge / discharge control of an assembled battery by the charge control method shown in FIG. It is explanatory drawing which shows the change of SOC of each cell in a disconnection cell block at the time of performing charging / discharging control of an assembled battery by the charge control method shown in FIG. It is a flowchart which shows the charge control method of this embodiment in the case of plug-in charge. It is a graph which shows the change of the open circuit voltage of a disconnection cell block with respect to SOC of a normal cell block at the time of performing charge / discharge control of an assembled battery by the charge control method shown in FIG. It is explanatory drawing which shows the change of SOC of each cell in a disconnection cell block at the time of performing charging / discharging control of an assembled battery by the charge control method shown in FIG.

<Configuration of Electric Vehicle to which Control Method of Battery Assembly of this Embodiment is Applied>
Hereinafter, the configuration of the electric vehicle 100 to which the assembled battery control method of the present embodiment is applied will be described with reference to the drawings. In the following description, the electric vehicle 100 to which the control method of the present embodiment is applied is a hybrid vehicle driven by the motor generator 14 and the engine 16, and EV traveling that travels only by the motor generator 14 is possible. Although described as a plug-in hybrid vehicle capable of charging the assembled battery 10 mounted by an external power source, the present invention can also be applied to other electric vehicles such as an electric vehicle.

  The electric vehicle 100 includes an assembled battery 10, an inverter 13 connected to the assembled battery 10 through a positive electrode line 11 and a negative electrode line 12, a motor generator 14 for driving a vehicle controlled by the inverter 13, an engine 16, And a control unit 70 for controlling operations of the inverter 13, the motor generator 14, and the engine 16 and charging / discharging of the assembled battery 10. Further, an ignition switch 19 for starting and stopping the electric vehicle 100 is attached to the driver's seat of the electric vehicle 100. The ignition switch 19 is connected to the control unit 70.

  The output shaft of the motor generator 14 and the output shaft of the engine 16 are connected to a power split mechanism 15 that divides the output of the engine 16 into a driving force for wheels 18 and a driving force for driving the motor generator 14 as a generator. Yes. The output shaft of the power split mechanism 15 is configured to drive the wheels 18 via the differential gear 17.

  The assembled battery 10 is formed by connecting cell blocks 20, 30, 40, and 50 in which a plurality of cells 21, 31, 41, and 51 of rechargeable secondary batteries such as lithium ion batteries are connected in parallel. Hereinafter, the structure of the cell block will be described using the cell block 20 as an example. The structure of the cell blocks 30, 40, 50 is the same as that of the cell block 20, and for the same parts, the cell block 30 is the same in the 30th place, the cell block 40 is the same in the 40th place, The cell block 50 is assigned the same number in the 50's.

  The cell block 20 includes a plurality of cylindrical lithium ion battery cells 21, a positive electrode parallel bus bar 24, a positive electrode connection bus bar 25, a negative electrode parallel bus bar 27, and a negative electrode connection bus bar 26.

  As shown in FIG. 2A, the positive electrode parallel bus bar 24 is a flat metal plate in which openings 24a are arranged in accordance with the arrangement of the cells 21. A plurality of positive electrode parallel bus bars 24 are arranged from the periphery of each opening 24a toward the center of each opening 24a. The positive connection bus bar 25 extends. As shown in FIG. 3, the positive electrode connection bus bar 25 is an elongated plate that is bent obliquely downward from the positive electrode parallel bus bar 24 toward the positive electrode 22 of the cell 21. As shown in FIGS. 2A and 3, the tip 28 of the positive connection bus bar 25 is connected to the positive electrode 22 by resistance welding. Thus, the positive electrodes 22 of the plurality of cells 21 are connected in parallel by the positive electrode parallel bus bar 24 and the plurality of positive electrode connection bus bars 25.

  As shown in FIGS. 2B and 3, the negative electrode parallel bus bar 27 and the negative electrode connection bus bar 26 have the same structure as the positive electrode parallel bus bar 24 and the positive electrode connection bus bar 25, and the negative electrode connection bus bar 26 has an opening 27 a of the negative electrode parallel bus bar 27. This is an elongated plate that is bent obliquely upward from the peripheral edge of the cell 21 toward the negative electrode 23 of the cell 21. As shown in FIGS. 2B and 3, the tip 29 of the negative electrode connection bus bar 26 is connected to the negative electrode 23 by resistance welding. The negative electrodes 23 of the plurality of cells 21 are connected in parallel to a negative electrode parallel bus bar 27 and a plurality of negative electrode connection bus bars 26.

  Therefore, the positive parallel bus bar 24 and the plurality of positive connection bus bars 25 constitute a positive parallel connection line, and the negative parallel bus bar 27 and the plurality of negative connection bus bars 26 constitute a negative parallel connection line. Yes.

  As shown in FIG. 1, the positive parallel bus bar 24 of the cell block 20 is connected to the positive line 11 of the assembled battery 10, and the negative parallel bus bars 27, 37, 47 of the cell block 20 to the cell block 40 are connected from the cell block 30 to the cell. The positive and parallel bus bars 34, 44, and 54 of the block 50 are connected by serial bus bars, respectively. The negative parallel bus bar 57 of the cell block 50 is connected to the negative electrode line 12 of the assembled battery 10. Thus, the cell blocks 20, 30, 40, 50 are connected in series.

  As shown in FIG. 1, between each positive electrode parallel bus bar 24, 34, 44, 54 and each negative electrode parallel bus bar 27, 37, 47, 57 of each cell block 20, 30, 40, 50, each cell block. Voltage sensors 64, 65, 66, and 67 for detecting block voltage values V1, V2, V3, and V4 of 20, 30, 40, and 50 are attached. A voltage sensor 61 for detecting the voltage value Vb of the assembled battery 10 is attached between the positive electrode line 11 and the negative electrode line 12 of the assembled battery 10, and the current value Ib of the assembled battery 10 is connected to the positive electrode line 11. A current sensor 62 is attached to detect. Further, a temperature sensor 63 for detecting the temperature Tb of the assembled battery 10 is attached to the assembled battery 10. Furthermore, as shown in FIG. 1, a connector 90 that can be connected to an external power source is connected to the positive electrode line 11 and the negative electrode line 12.

  The control unit 70 includes a CPU 71 that performs information processing and calculation therein, a memory 72 that stores control programs, control data, and the like, a sensor that is connected to the voltage sensors 61 and 64 to 67, the current sensor 62, and the temperature sensor 63. The computer includes a device interface 73, and the CPU 71, the memory 72, and the sensor / device interface 73 are mutually connected by a data bus 74. The ECU 80 is also a computer that includes a CPU that performs information processing and computation and a memory that stores control programs, control data, and the like.

  Motor generator 14 receives electric power output from battery pack 10 to drive electric vehicle 100, converts kinetic energy generated during braking of electric vehicle 100 into electric power, and charges battery pack 10. Therefore, the battery pack 10 is repeatedly charged and discharged while the electric vehicle 100 is traveling. Note that the current value Ib of the battery pack 10 is such that the discharge current is positive (+) and the charge current is negative (−).

<Changes in driving mode of electric vehicle and SOC of battery pack>
Next, referring to FIG. 4, the travel mode of the electric vehicle 100 and changes in the SOC of the assembled battery 10, the cell blocks 20, 30, 40, 50 and the cells 21, 31, 41, 51 will be described. 4 shows only changes in the SOC of the cell block 20 and the cell 21, but all the cells 21, 31, 41, and 51 of the cell blocks 20, 30, 40, and 50 are all normally connected without disconnection. Therefore, changes in SOC of other cell blocks and cells are the same as changes in SOC of the cell block 20 and cell 21. As shown in FIG. 4A, the electric vehicle 100 includes a hybrid travel mode (hereinafter, referred to as an HV mode) that travels by the engine 16 and the motor generator 14, and an electric travel mode (hereinafter, that is traveled by only the motor generator 14). The vehicle can travel in two modes (referred to as EV mode). The electric vehicle 100 can perform plug-in charging in which an external power source is connected to the connector 90 shown in FIG. 1 and the assembled battery 10 is charged by the external power source.

  When the electric vehicle 100 is traveling in the HV mode as between the time t0 and the time t1 shown in FIG. 4A, the SOC of the assembled battery 10 is within a predetermined range centered on a certain SOC. It is controlled to become. As shown in FIG. 4B, the SOC of each cell block 20, 30, 40, 50 and the SOC of each cell 21, 31, 41, 51 change in the same manner as the SOC of the battery pack 10.

  When the assembled battery 10 of the electric vehicle 100 is charged by plug-in charging as between time t2 and t3 in FIG. 4A, the SOC of the assembled battery 10 increases from about 50% to about 90%, for example. To do. As shown in FIG. 4C, the SOC of each cell block 20, 30, 40, 50 and the SOC of each cell 21, 31, 41, 51 rise as well as the SOC of the battery pack 10. When the electric vehicle 100 travels in the EV mode from time t4 to time t5 in FIG. 4A, the SOC of the assembled battery 10 decreases from about 90% at time t4 to 20% at time t5. As shown in FIG. 4 (d), the SOC of each cell block 20, 30, 40, 50 and the SOC of each cell 21, 31, 41, 51 also decrease in the same manner as the SOC of the battery pack 10. After time t5 shown in FIG. 4A, electric vehicle 100 travels again in the HV mode. When shifting to the HV mode at time t5, the SOC of the assembled battery 10 is again controlled to be within a predetermined range centered on a certain SOC, and as shown in FIG. 4 (e), each cell block 20, 30 is controlled. , 40, 50 and the SOC of each cell 21, 31, 41, 51 are controlled in the same manner as the SOC of the battery pack 10.

<Connection line disconnection and re-conduction>
Next, the disconnection and re-conduction of the negative electrode connection bus bar 26 will be briefly described with reference to FIG. As shown in FIG. 5A, in the normal state, the negative electrode connection bus bar 26 is bent obliquely upward from the peripheral edge of the opening 27a of the negative electrode parallel bus bar 27 toward the negative electrode 23 of the cell 21, and the tip 29 thereof is negative electrode 23. It is resistance welded. As shown in FIG. 5B, when the negative electrode connection bus bar 26 is broken between the tip 29 and the negative electrode parallel bus bar 27 due to vibration of the electric vehicle 100 or the like, a broken portion 26a is formed. No current flows through the normal cell 21, or a disconnected cell 21a as shown in FIG. Thereafter, when the broken end on the tip 29 side of the negative electrode connection bus bar 26 and the broken end on the negative electrode parallel bus bar 27 side come into contact with each other due to vibration of the electric vehicle 100 or the like, as shown in FIG. As shown in FIG. 5 (d), a spark is generated, and both broken ends are welded to form a re-welded portion 26b. The negative electrode parallel bus bar 27 and the negative electrode 23 of the cell 21 are reconnected, and the disconnected cell 21a is normal. Return to cell 21.

  As described above, when all the cells 21 of the cell block 20 are normally connected, the SOCs of all the cells 21 are substantially the same. For this reason, as shown in FIG. 6A, the SOC of the normal cell 21 and the disconnected cell 21a are substantially the same immediately after the negative electrode connection bus bar 26 is disconnected and becomes the disconnected cell block 20a including the disconnected cell 21a. ing. When the disconnected cell block 20a is charged in this state, as shown in FIG. 6B, the SOC of the normal cell 21 rises, but the SOC of the disconnected cell 21a is maintained at the SOC at the time of disconnection. Then, as shown in FIG. 6C, when the negative electrode connection bus bar 26 of the disconnection cell 21a is turned on again, a large current flows instantaneously from the normal cell 21 toward the disconnection cell 21a, and the temperature of the disconnection cell 21a or the surroundings In some cases, the temperature of the normal cell 21 rises and the broken cell block 20a deteriorates. After re-conduction, the disconnected cell 21a becomes the normal cell 21, so that the SOCs of all the cells 21 are substantially the same.

  Further, as shown in FIG. 7A, the SOC of the cell 21 at the time of disconnection is high, and thereafter, as shown in FIG. After the SOC of 21a is maintained in a high state, when the negative electrode connection bus bar 26 is re-conducted as shown in FIG. 7 (c), the disconnection cell 21a is reversed, as described with reference to FIG. A large current instantaneously flows toward the normal cell 21, and the temperature of the disconnected cell 21a or the temperature of the surrounding normal cell 21 increases, and the disconnected cell block 20a may deteriorate.

<Open circuit voltage characteristics of normal cell block and open cell block>
Next, the open-circuit voltage characteristics of the normal cell block 20 in which all the cells 21 are normally connected and the open-circuit voltage characteristics of the disconnected cell block 20a including the disconnected cell 21a will be described with reference to FIG. In the following description, the open circuit voltage is described as OCV. The characteristic curve of the cell block OCV with respect to the SOC of the normal cell block 20 is a characteristic curve in which the OCV increases as the SOC increases, as indicated by the solid line q in FIG. If the capacity of the normal cell block 20 is capacity Q20 (A × h), the SOC of the normal cell block at the capacity Q20 is 100%, and the OCV at that time is OCV (100%).

In the disconnected cell block 20a, only the normal cell 21 is charged / discharged, and the disconnected cell 21a is not charged / discharged. For this reason, the capacity Q20a (A × h) of the disconnected cell block 20a is smaller than the capacity Q20 (A × h) of the normal cell block 20 as shown in the following equation (1).

Q20a = Q20 × (number of normal cells−number of disconnected cells) / number of all cells (1)

  Accordingly, in the disconnected cell block 20a, the SOC of the disconnected cell block 20a with the capacity Q20a smaller than the capacity Q20 is 100%, and the OCV at that time is OCV (100%). Therefore, as shown in FIG. 8, when the SOC of the normal cell block 20 is set on the horizontal axis, the OCV characteristic curve of the broken cell block 20a is the OCV of the normal cell block 20 indicated by the solid line q as shown by the broken line p. This characteristic curve is compressed in the horizontal direction by (Q20a / Q20). Since the OCV value for each SOC is the same in both the normal cell block 20 and the disconnected cell block 20a, the SOC of the normal cell block 20 and the SOC of the disconnected cell block 20a are as shown at the intersection of the broken line p and the solid line q shown in FIG. Are the same SOC0, the OCV of the normal cell block 20 and the OCV of the disconnected cell block 20a are the same.

  As described above with reference to FIGS. 6 and 7, when the negative electrode connection bus bar 26 is disconnected, the SOCs of the normal cell 21 and the disconnected cell 21a are substantially the same. Therefore, the SOC of the disconnected cell block 20a at this time And the SOC of the normal cell blocks 30, 40, 50 are the same. Therefore, when the negative electrode connection bus bar 26 is disconnected, the OCV of the disconnected cell block 20a is the same as the OCV of the normal cell blocks 30, 40, 50, and the difference between them is zero. That is, SOC0 shown in FIG. 8 in which the difference between the OCV of the disconnected cell block 20a and the OCV of the normal cell blocks 30, 40, 50 becomes zero becomes the SOC when the disconnection occurs in the negative electrode connection bus bar 26.

  Since the assembled battery 10 has a plurality of cell blocks 20, 30, 40, 50 connected in series, the assembled battery 10 is discharged to drive the motor generator 14, or the assembled battery 10 is connected by an external power source via the connector 90. 10 is charged, the current value Ib flowing through each cell block 20, 30, 40, 50 is the same. For this reason, even when a disconnection occurs in the negative electrode connection bus bar 26 of the cell block 20 and the disconnection cell block 20a is formed, the disconnection cell block 20a and the other normal cell blocks 30, 40, 50 are charged and discharged with the same current. The Since the capacity Q20a of the disconnected cell block 20a is smaller than the capacity Q20 of the normal cell block 20 as shown in the equation (1), when the charge / discharge is performed with the same current as that of the normal cell blocks 30, 40, 50. The SOC of the disconnected cell block 20a changes faster than the SOC of the normal cell blocks 30, 40, and 50.

Assuming that the SOC (%) value at the time of disconnection is the disconnection occurrence SOC, the SOC (%) value of the disconnection cell block 20a and the normal cell blocks 30, 40 when the assembled battery 10 is charged / discharged after the disconnection occurs. The relationship with the value of 50 SOC (%) is as follows.

Disconnection cell block SOC value = disconnection generation SOC value− (disconnection generation SOC value−normal cell block SOC value) × (Q20 / Q20a) (2)

Therefore, for example, in 6 parallels, when one of the negative connection bus bars 26 is disconnected at an SOC of 50% and then the normal cell blocks 30, 40, 50 are charged to an SOC of 80%, the SOC 80 of the normal cell blocks 30, 40, 50 is obtained. The SOC of the disconnected cell block 20a with respect to%

50− (50−80) × 6/5 = 86 (3)
Therefore, it becomes 86%.

Further, in 6 parallels, when one of the negative connection bus bars 26 is disconnected at an SOC of 50%, and then the normal cell blocks 30, 40, 50 are discharged to an SOC of 20%, the normal cell blocks 30, 40, 50 have an SOC of 20%. The SOC of the disconnected cell block 20a is

50− (50−20) × 6/5 = 14 (4)
14%.

  For this reason, as shown in FIG. 8, when the battery block 10a is charged after the cell block 20 becomes the disconnected cell block 20a when the SOC is SOC0 of about 50%, the SOC of the disconnected cell block 20a having a smaller capacity is obtained. It rises faster than the SOC of the normal cell blocks 30, 40, 50. Then, as shown in FIG. 8, the SOC of the disconnected cell block 20a reaches 100% before the SOC of the normal cell blocks 30, 40, 50 reaches 100%, and the OCV of the disconnected cell block 20a is equal to the normal cell block 30. , 40, 50 reaches OCV (100%) before it becomes OCV (100%) with respect to SOC 100%. Therefore, as shown by the broken line p and the solid line q in FIG. 8, when the assembled battery 10 is charged after the occurrence of the disconnection, the OCV of the disconnected cell block 20a becomes the OCV of the normal cell blocks 30, 40, 50 as the battery is charged. The absolute value (| ΔOCV |) of the difference between the OCV of the disconnected cell block 20a and the OCV of the normal cell blocks 30, 40, 50 increases.

  On the contrary, when the assembled battery 10 is discharged after the cell block 20 becomes the disconnected cell block 20a when the SOC is SOC0 of about 50%, the SOC of the disconnected cell block 20a having a smaller capacity is the normal cell block 30, 40. , Drops faster than 50 SOC. Then, the SOC of the disconnected cell block 20a reaches 0% before the SOC of the normal cell blocks 30, 40, 50 reaches 0%, and the OCV of the disconnected cell block 20a is equal to that of the normal cell blocks 30, 40, 50. OCV (0%) is reached before the OCV becomes OCV (0%) relative to SOC 0%. Therefore, as shown by the broken line p and the solid line q in FIG. 8, when the assembled battery 10 is discharged after the occurrence of the disconnection, the OCV of the disconnected cell block 20a becomes the OCV of the normal cell blocks 30, 40, and 50 as the battery is discharged. The absolute value (| ΔOCV |) of the difference between the OCV of the disconnected cell block 20a and the OCV of the normal cell blocks 30, 40, 50 increases.

  In the assembled battery charge / discharge control method according to the present embodiment, when charge / discharge is performed after disconnection of the positive electrode or negative electrode connection bus bars 25, 26 in the assembled battery 10, the disconnected cell block 20a and the normal cell blocks 30, 40, 50 When there is a difference in the OCV between the two cell blocks due to the difference in the SOC between the two cell blocks, and when there is a disconnection in the SOC where the difference in the OCV between the disconnected cell block 20a and the normal cell blocks 30, 40, 50 is zero The charge / discharge control of the assembled battery 10 is performed by using the SOC.

<The charge / discharge control method of the assembled battery of this embodiment>
<Operation of control unit during HV traveling>
Hereinafter, the charge / discharge control method when the electric vehicle 100 is traveling in the HV mode will be described with reference to FIGS. 9 to 11. First, the electric vehicle 100 is traveling in the HV mode, and the SOC of the assembled battery 10 is controlled to fall within the control range W0 where the SOC 0 is the SOC control center C0 of the assembled battery 10. A case where the SOC of battery 10 is SOC0 will be described. In the battery pack charge / discharge control method of this embodiment, the CPU 71 executes a charge / discharge control program stored in the memory 72 of the control unit 70 shown in FIG. 1. The control unit 70 repeatedly executes the operation of the flowchart shown in FIG. 9 at a predetermined cycle such as 0.1 seconds.

  As shown in step S101 of FIG. 9, the control unit 70 determines whether there is a broken cell block. As described above, when charging / discharging is performed after disconnection of the positive or negative electrode connection bus bars 25 and 26 in the assembled battery 10, a difference occurs between the OCV of the disconnected cell block and the OCV of the normal cell block. Therefore, the control unit 70 sets the voltage values V1 to V4 of the cell blocks 20, 30, 40, and 50 detected by the voltage sensors 64 to 67 when the electric vehicle 100 is stopped and the ignition switch 19 is turned off. It is detected as each OCV of the cell block 20, 30, 40, 50. Then, when there is a cell block having a voltage higher or lower than the average voltage Vave by a predetermined voltage ΔS among the voltage values V1 to V4, the control unit 70 determines that the cell block is a disconnected cell block. Identify. The method for identifying the broken cell block is not limited to the above method, and may be performed by another method.

  If the control unit 70 determines that there is no broken cell block, the control unit 70 ends the execution of the program without executing steps S102 to S107 shown in FIG.

  In the following description, in step S101, the control unit 70 identifies the cell block 20 as a disconnected cell block in which disconnection has occurred, determines that the other cell blocks 30, 40, and 50 are normal cell blocks, A description will be given assuming that the process proceeds to step S102.

  When the electric vehicle 100 is in the HV travel mode in step S102, the control unit 70 determines whether each OCV of each cell block 20, 30, 40, 50 has been detected. Proceed to step S103 of step 9. If the OCV cannot be detected, the program execution is terminated.

When the vehicle is traveling in the HV mode, the electric vehicle 100 always charges and discharges the assembled battery 10, and thus it is difficult to directly detect the OCV. Therefore, when the electric vehicle 100 is stopped or stopped and the current value Ib detected by the current sensor 62 is small, the control unit 70 uses the voltage sensors 64 to 67 to generate a voltage value V1 that is a closed circuit voltage (CCV). ˜V4 is detected. Further, the control unit 70 obtains the internal resistance Ra of each cell block 20, 30, 40, 50 from a map or the like stored in the memory 72 based on the temperature Tb of the assembled battery 10 detected by the temperature sensor 63. And the control part 70 detects OCV by estimating OCV by the following formula | equation (5). Here, the case where the current value Ib detected by the current sensor 62 is small is a case where the current value Ib is equal to or smaller than the current threshold value Ibs1 so that the OCV estimation error when the OCV is calculated by the equation (1) is equal to or smaller than a predetermined range.

OCV = CCV + Ra × Ib (5)

Further, when the electric vehicle 100 is stopped and the current value Ib detected by the current sensor 62 is very small, the voltage values V1 to V4 (CCV) detected by the voltage sensors 64 to 67 are used as the cell blocks 20, 30, The OCV may be detected by regarding 40,50 OCV. Here, when the current value Ib detected by the current sensor 62 is very small, the current threshold value Ibs2 is such that the estimated error of the OCV when the voltage values V1 to V4 (CCV) are regarded as OCV is equal to or less than a predetermined range. This is the case. The current threshold value Ibs2 is a value smaller than the current threshold value Ibs1 described above.

  First, since the cell block 20 is identified as a disconnected cell block in step S101, the control unit 70 can detect disconnection if the OCVs of the disconnected cell block 20a and the normal cell blocks 30, 40, 50 can be detected in step S102. The absolute value (| ΔOCV |) of the difference between the OCV of the cell block 20a and the OCV of the normal cell blocks 30, 40, 50 is calculated. At this time, the OCV of the normal cell blocks 30, 40, 50 may use an average value of the plurality of normal cell blocks 30, 40, 50.

  After calculating | ΔOCV | in step S103 of FIG. 9, the control unit 70 proceeds to step S104 and determines whether or not | ΔOCV | is smaller than a predetermined threshold value. The predetermined threshold is obtained by adding detection errors of the voltage sensors 64 to 67 and OCV estimation errors to zero. Then, in step S104, if | ΔOCV | is less than the predetermined threshold value, control unit 70 considers | ΔOCV | to be zero. That is, the OCV of the disconnected cell block 20a and the OCV of the normal cell blocks 30, 40, 50 are regarded as the same. As described above with reference to FIG. 8, the SOC in which | ΔOCV |, which is the difference between the OCV of the disconnected cell block 20 a and the OCV of the normal cell blocks 30, 40, 50 becomes zero, is disconnected in the cell block 20. Is the SOC when a broken cell block 20a is generated. As described above with reference to FIGS. 6 and 7, when a disconnection occurs, the SOC of the disconnected cell 21a is the SOC of the disconnected cell block 20a and the SOC of the normal cell blocks 30, 40, 50, that is, a set. It is the same as the SOC of the battery 10. Therefore, when | ΔOCV | is less than the predetermined threshold, the SOC of the current assembled battery 10 is the SOC of the disconnected cell 21a.

  As shown in FIG. 10, in SOC0 which is the SOC of the current assembled battery 10, since | ΔOCV | is less than a predetermined threshold value, the control unit 70 determines YES in step S104 and proceeds to step S105, and proceeds to step S105. The SOC of the battery 10 is set as the SOC of the disconnected cell 21a, and the process proceeds to step S106. Then, SOC0, which is the SOC of the current assembled battery 10, is set as the SOC control center C0 of the assembled battery 10.

  Then, the control unit 70 proceeds to step S107, and limits the SOC control range of the assembled battery 10 to a predetermined control range Ws that is narrower than the current W0. As described with reference to FIG. 6 and FIG. 7, the predetermined control range Ws is the normal state of the disconnected cell 21a due to the current flowing into the disconnected cell 21a when the disconnected cell block 20a is re-conducted or the current flowing out of the disconnected cell 21a. The range in which the temperature rise generated in the cell 21 does not cause deterioration of the disconnected cell 21 a or the normal cell 21, and the electric vehicle 100 is in a range where HV traveling is possible while charging and discharging the assembled battery 10. .

  If the control part 70 restrict | limits the SOC control range of the assembled battery 10 to the predetermined control range Ws by step S107, the execution of the program of the time will be complete | finished.

  As described above, in the charge / discharge control method of the present embodiment, the SOC control center of the assembled battery 10 is set as the SOC of the disconnected cell 21a, and the SOC control range of the assembled battery 10 is limited to a predetermined control range Ws narrower than the initial W0. By doing so, it is possible to suppress the current flowing through the disconnected cell 21a when the disconnected cell 21a is re-conducted, and to prevent the assembled battery 10 from deteriorating.

  If | ΔOCV | is equal to or greater than the predetermined threshold value, the control unit 70 determines NO in step S104 and proceeds to step S108, where the OCV of the disconnected cell block 20a and the OCV of the normal cell blocks 30, 40, and 50 are determined. It is determined whether or not the difference ΔOCV is zero or more. When ΔOCV is greater than or equal to zero, the OCV of the broken cell block 20a indicated by the broken line a in FIG. 10 is larger than the OCV of the normal cell blocks 30, 40, and 50 indicated by the solid line b in FIG. Is SOC1 larger than SOC0 which is SOC of the disconnection cell 21a.

  In this case, as shown in FIG. 10, the electric vehicle 100 is controlled such that the SOC of the assembled battery 10 falls within the control range W1 centered on the SOC control center C10 of the assembled battery 10. The SOC of the battery 10 is SOC1 within the control range W1. Further, as shown in FIG. 11A, the SOC control center C10 and the SOC1 that is the SOC of the current assembled battery 10 are both larger than the SOC0 that is the SOC of the disconnected cell 21a, and the normal cells in the disconnected cell block 20a. The SOC of 21 is larger than the SOC of the disconnected cell 21a.

  If ΔOCV is greater than or equal to zero and it is determined YES in step S108, control unit 70 proceeds to step S109, and reduces the SOC control center of battery pack 10 from current SOC control center C10 of battery pack 10 by ΔSOC1. To C11.

  As shown in FIG. 10, when the SOC control center of the battery pack 10 is C11, the battery pack 10 is controlled so that the SOC falls within the control range W1 centered on the SOC control center C11 of the battery pack 10. . For this reason, the SOC of the assembled battery 10 approaches SOC0, which is the SOC of the disconnected cell 21a, as compared with the case where the SOC control center of the assembled battery 10 is C10, and | ΔOCV |

  When the SOC control center of the battery pack 10 is reduced by ΔSOC1 in step S109, the control unit 70 ends the execution of the program. ΔSOC1 may be about 0.5%, for example.

  When the predetermined period elapses, the control unit 70 again starts executing the program shown in the flowchart of FIG. Since the cell block 20 is identified as the disconnected cell block 20a when the previous program is executed, the control unit 70 determines YES in step S101 of FIG. 9, and proceeds to step S102. When the OCV of the disconnected cell block 20a and the normal cell blocks 30, 40, 50 can be detected at that time, the process proceeds to step S103 in FIG. 9 to calculate | ΔOCV |.

  As shown in FIG. 10, the SOC control center C11 of the assembled battery 10 newly set by the execution of the previous program is still larger than SOC0 which is the SOC of the disconnected cell 21a, | ΔOCV | is equal to or greater than the threshold value, and ΔOCV Since ≧ 0, the control unit 70 determines NO in step S104, determines YES in step S108, proceeds to step S109, and moves the SOC control center of the assembled battery 10 from the current SOC control center C11 of the assembled battery 10. Decrease by ΔSOC1. When the SOC control center of the battery pack 10 is reduced by ΔSOC1 in step S109, the control unit 70 ends the execution of the program.

  Then, every time the program is executed, the control unit 70 decreases the SOC of the battery pack 10 by reducing the SOC control center of the battery pack 10 by ΔSOC1. As a result, | ΔOCV | is gradually reduced. If | ΔOCV | becomes less than the threshold value in step S104, the control unit 70 estimates the SOC of the assembled battery 10 at that time as the SOC of the disconnected cell 21a as shown in step S105, and proceeds to step S106. The SOC of the battery pack 10 at that time is set as the SOC control center of the battery pack 10. Then, the control unit 70 proceeds to step S107, limits the SOC control range of the battery pack 10 to a predetermined control range Ws narrower than the current W0, and ends the execution of the program for that time.

  At this time, the SOC of the assembled battery 10 is SOC0 similar to the SOC of the disconnected cell 21a, and as shown in FIG. 11B, the SOC of the normal cell 21 in the disconnected cell block 20a is the SOC of the disconnected cell 21a. The SOC control center of the battery pack 10 is also the same SOC0.

  On the other hand, if | ΔOCV | is equal to or greater than a predetermined threshold value and ΔOCV is negative, control unit 70 determines NO in step S108 shown in FIG. 9 and proceeds to step S110. In this case, as shown in FIG. 10, the electric vehicle 100 is controlled so that the SOC of the assembled battery 10 falls within the control range W2 centering on the SOC control center C20 of the assembled battery 10. The SOC of the battery 10 is SOC2 within the control range W2. Further, as shown in FIG. 11C, the SOC control center C20 and the SOC2 that is the SOC of the current assembled battery 10 are both smaller than the SOC0 that is the SOC of the disconnected cell 21a, and the normal cells in the disconnected cell block 20a. The SOC of 21 is smaller than the SOC of the disconnected cell 21a.

  In this case, contrary to the case of ΔOCV ≧ 0 described above, the control unit 70 increases the SOC of the battery pack 10 by increasing the SOC control center of the battery pack 10 by ΔSOC2 every time the program is executed. Go. Accordingly, | ΔOCV | is gradually reduced. If | ΔOCV | becomes less than the threshold value in step S104, the control unit 70 estimates the SOC of the assembled battery 10 at that time as the SOC of the disconnected cell 21a as shown in step S105, and proceeds to step S106. The SOC of the battery pack 10 at that time is set as the SOC control center of the battery pack 10. Then, the control unit 70 proceeds to step S107, limits the SOC control range of the battery pack 10 to a predetermined control range Ws narrower than the current W0, and ends the execution of the program for that time.

  At this time, the SOC of the assembled battery 10 is SOC0 similar to the SOC of the disconnected cell 21a, and as shown in FIG. 11D, the SOC of the normal cell 21 in the disconnected cell block 20a is the SOC of the disconnected cell 21a. The SOC control center of the battery pack 10 is also the same SOC0.

  As described above, in the charge / discharge control method of this embodiment, as shown in FIGS. 11A to 11D, the SOC of the normal cell 21 in the disconnected cell block 20a is larger than the SOC of the disconnected cell 21a. If so, the SOC control center of the assembled battery 10 is gradually reduced. If the SOC of the normal cell 21 in the disconnected cell block 20a is smaller than the SOC of the disconnected cell 21a, the SOC control of the assembled battery 10 is performed. Increase the center little by little. Accordingly, | ΔOCV | is gradually reduced. When | ΔOCV | becomes less than a predetermined threshold, the SOC of the assembled battery 10 at that time is estimated to be the SOC of the disconnected cell 21a, and the SOC of the disconnected cell 21a that estimates the SOC control center of the assembled battery 10 To do. Further, the SOC control range of the battery pack 10 is limited to a predetermined control range Ws narrower than the initial W1 and W2. Thereby, the charging / discharging control method of this embodiment can suppress the electric current which flows into the disconnection cell 21a when the disconnection cell 21a re-conducts, and can suppress that the assembled battery 10 deteriorates.

<Operation of the control unit of the present embodiment during EV traveling>
Next, a charge / discharge control method when the electric vehicle 100 is traveling in the EV mode will be described with reference to FIGS. The control unit 70 repeatedly executes the program shown in the flowchart of FIG. 12 at a predetermined cycle. Control similar to the charge / discharge control during traveling in the HV mode described above with reference to FIGS. 9 to 11 will be briefly described.

  The program shown in the flowchart of FIG. 12 is based on the assumption that the program shown in FIG. 9 has been executed at least once and a broken cell block has been specified. Therefore, in the following description, similarly to the description of the previous embodiment, it is assumed that the cell block 20 is identified as a disconnected cell block, and the cell blocks 30, 40, 50 are determined to be normal cell blocks.

  As shown in Step S201 and Step S202 of FIG. 12, the control unit 70 determines whether or not traveling in the EV traveling mode is started after the ignition switch 19 is turned on. As shown in step S208 of FIG. 12, if the EV mode traveling is not started even after a predetermined standby time has elapsed, the control unit 70 ends the execution of the program at that time.

  When the EV running is started, the control unit 70 proceeds to step S203 in FIG. 12, and detects the OCV of the disconnected cell block 20a and the normal cell blocks 30, 40, and 50. As described above, the OCV may be calculated by estimating the OCV from the voltage values V1 to V4 detected by the voltage sensors 64 to 67, which are CCV, when the current value Ib is small. When the voltage values are very small, the voltage values V1 to V4 detected by the voltage sensors 64 to 67 may be detected as the OCV.

  When detecting the OCV, the control unit 70 proceeds to step S204 of FIG. 12, and calculates the absolute value (| ΔOCV |) of the difference between the OCV of the broken cell block 20a and the OCV of the normal cell blocks 30, 40, 50, Proceed to step S204. When | ΔOCV | is not less than the predetermined threshold value (when | ΔOCV | is equal to or larger than the predetermined threshold value), the control unit 70 proceeds to step S210 in FIG. 12, and the value of | ΔOCV | Judge whether it is shrinking more than usual.

  As shown in FIG. 13, the EV traveling is often started after the battery pack 10 is charged to the SOC 3 to the extent that the assembled battery 10 is almost fully charged by plug-in charging or the like. In this case, as shown in FIG. 13, SOC4, which is the SOC of the disconnected cell 21a, is lower than SOC3. Accordingly, when the SOC of the battery pack 10 decreases due to EV traveling, the current SOC of the battery pack 10 approaches the SOC 4 that is the SOC of the disconnected cell, and | ΔOCV | gradually decreases. Therefore, when it is determined YES in step S210, the control unit 70 repeats steps S203, S204, S205, and S210 until | ΔOCV | becomes less than a predetermined threshold value in step S204. If | ΔOCV | becomes less than the predetermined threshold value in step S205, in step S206, the SOC 4 at that time is estimated as the SOC of the disconnected cell 21a, and the process proceeds to step S207, where the control center of the assembled battery 10 is set to SOC4. . Then, the control unit 70 proceeds to step S208 and limits the SOC control range of the assembled battery 10 to a predetermined control range Ws narrower than W0 in the normal HV travel mode. Then, the control unit 70 proceeds to step S209, shifts from the EV traveling mode to the HV traveling mode, and ends the execution of the program. Thereafter, the control unit 70 controls the electric vehicle 100 in the HV mode while controlling the SOC of the assembled battery 10 so that the SOC of the assembled battery 10 falls within the predetermined control range Ws.

  On the other hand, when the value of | ΔOCV | is increased in step S210 in FIG. 12 from the previous execution of the program, the control unit 70 determines that the current SOC of the assembled battery 10 is higher than the SOC of the disconnected cell 21a. If the SOC of the battery pack 10 decreases due to the EV running, the SOC of the battery pack 10 is separated from the SOC of the disconnected cell, and | ΔOCV | is increased, and the process proceeds to step S211 and the current battery pack 10 The SOC is set at the SOC control center of the battery pack 10, and the process proceeds to step S209. The EV travel mode is changed to the HV travel mode, and the program execution is terminated. Then, the program shown in the flowchart of FIG. 9 is executed to search for SOC0, which is the SOC of the disconnected cell 21a, and when SOC0 can be specified, the SOC control center of the battery pack 10 is set to SOC0, and the control range is set to the predetermined control range Ws. And

  As described above, in the charge / discharge control method according to the present embodiment, as shown in FIG. 14A, the SOC of the normal cell 21 in the disconnected cell block 20a at the start of the electric vehicle 100 during EV traveling is changed to that of the disconnected cell 21a. If the SOC is larger than the SOC, the EV travel is performed until the SOC of the assembled battery 10 becomes the SOC of the disconnected cell 21a. When | ΔOCV | becomes less than a predetermined threshold, the SOC of the assembled battery 10 at that time is reduced. As shown in FIG. 14B, the SOC control center of the battery pack 10 is set as the SOC of the battery breaker cell 21a, and the SOC control range of the battery pack 10 is set in the normal HV mode. Is limited to a predetermined control range Ws narrower than the control range W0. Thereafter, the electric vehicle 100 is controlled in the HV mode. Thereby, when the disconnection cell 21a re-conducts, the current flowing through the disconnection cell 21a can be suppressed, and deterioration of the assembled battery 10 can be suppressed.

<Operation of the battery control device of the present embodiment during plug-in charging>
Next, a charge / discharge control method when plugging in the electric vehicle 100 will be described with reference to FIGS. 15 to 17. The control unit 70 repeats the program shown in the flowchart of FIG. 15 at a predetermined cycle. Note that the vehicle is traveling in the EV mode described with reference to FIGS. 12 to 14 and the same control as the charge / discharge control during traveling in the HV mode described above with reference to FIGS. The same control as the charge / discharge control in this case will be described briefly.

  The program shown in the flowchart of FIG. 15 is based on the assumption that the program shown in FIG. 9 has been executed at least once and a broken cell block has been specified. Therefore, in the following description, similarly to the description of the previous embodiment, it is assumed that the cell block 20 is identified as a disconnected cell block, and the cell blocks 30, 40, 50 are determined to be normal cell blocks.

  As shown in step S301 in FIG. 15, the control unit 70 determines whether or not plug-in charging is started after the ignition switch 19 is turned off. As shown in step S308 of FIG. 15, when the plug-in charging is not started even after a predetermined standby time has elapsed, the control unit 70 ends the execution of the program at that time.

  When plug-in charging is started, the control unit 70 proceeds to step S303 in FIG. 15 and detects OCVs of the disconnected cell block 20a and the normal cell blocks 30, 40, and 50. The OCV may be detected, for example, by detecting the OCV with the voltage sensors 64 to 67 when the charging stops at a predetermined timing and the current value Ib becomes zero, and the current value is the same as described above. The OCV may be estimated and calculated from the voltage values V1 to V4 detected by the voltage sensors 64 to 67 that are CCV when Ib is small, or the voltage detected by the voltage sensors 64 to 67 when the current value Ib is very small. The values V1 to V4 may be detected as OCV.

  When detecting the OCV, the control unit 70 proceeds to step S304 in FIG. 15 and calculates the absolute value (| ΔOCV |) of the difference between the OCV of the broken cell block 20a and the OCV of the normal cell blocks 30, 40, 50, Proceed to step S305. If | ΔOCV | is not less than the predetermined threshold value (when | ΔOCV | is equal to or greater than the predetermined threshold value), the control unit 70 proceeds to step S310 in FIG. 15, and the value of | ΔOCV | Judge whether it is shrinking more than usual.

  As shown in FIG. 16, plug-in charging is often started in a state where the SOC of the battery pack 10 is low as after EV traveling. In this case, as shown in FIG. 16, SOC6 that is the SOC of the disconnected cell 21a is higher than SOC5 that is the SOC of the current assembled battery 10. Therefore, when the SOC of the assembled battery 10 increases due to plug-in charging, the SOC of the assembled battery 10 approaches the SOC 6 that is the SOC of the disconnected cell, and | ΔOCV | gradually decreases. Therefore, when it is determined YES in step S310, the control unit 70 repeats steps S303, S304, S305, and S310 until | ΔOCV | becomes less than a predetermined threshold value in step S304. If | ΔOCV | becomes less than the predetermined threshold value in step S305, in step S306, the SOC 6 at that time is estimated as the SOC of the disconnected cell 21a, and the process proceeds to step S307, where the control center of the assembled battery 10 is set to SOC6. . Then, the control unit 70 proceeds to step S308, and limits the SOC control range of the battery pack 10 to a predetermined control range Ws narrower than W0 in the normal HV travel mode. Then, the control unit 70 proceeds to step S309, stops plug-in charging, and ends the execution of the program. Thereafter, the control unit 70 controls the electric vehicle 100 in the HV mode while controlling the SOC of the assembled battery 10 so that the SOC of the assembled battery 10 falls within the predetermined control range Ws.

  On the other hand, when the value of | ΔOCV | is increased in step S310 of FIG. 15 from the previous execution of the program, the control unit 70 determines that the current SOC of the assembled battery 10 is higher than the SOC of the disconnected cell 21a. If the SOC of the battery pack 10 increases greatly due to plug-in charging, the SOC of the battery pack 10 is separated from the SOC of the disconnected cell, and it is determined that | ΔOCV | is increased, and the process proceeds to step S311. Is set at the SOC control center of the battery pack 10 and the process proceeds to step S309, the plug-in charging is stopped, the travel mode of the electric vehicle 100 is shifted to the HV mode, and the execution of the program is terminated. Then, the program shown in the flowchart of FIG. 9 is executed to search for SOC0 that is the SOC of the disconnected cell 21a, and when SOC0 can be estimated, the SOC control center of the battery pack 10 is set to SOC0, and the control range is set to the predetermined control range Ws. And

  As described above, in the charge / discharge control method of the present embodiment, as shown in FIG. 17A, the SOC of the normal cell 21 in the disconnected cell block 20a at the start of plug-in charging of the electric vehicle 100 is disconnected. If the SOC of the assembled battery 10 is the SOC of the disconnected cell 21a, plug-in charging is performed until the SOC of the assembled battery 10 becomes the SOC of the disconnected cell 21a. As shown in b), the SOC control center of the battery pack 10 is set to the SOC of the disconnected cell 21a, and the SOC control range of the battery pack 10 is set to a predetermined control range Ws narrower than the control range W0 in the normal HV mode. Restrict. Thereafter, the electric vehicle 100 is controlled in the HV mode. Thereby, when the disconnection cell 21a re-conducts, the current flowing through the disconnection cell 21a can be suppressed, and deterioration of the assembled battery 10 can be suppressed.

  As described above, the charge / discharge control method according to the present embodiment has a voltage difference (| ΔOCV) between the OCV of the normal cell blocks 30, 40, and 50 and the OCV of the disconnected cell block 20a when the assembled battery 10 is charged and discharged. Based on the reduction of |), the SOC of the disconnected cell 21a is estimated, and the assembled battery 10 is charged and discharged so that the SOC of the assembled battery 10 is within the predetermined control range Ws centered on the SOC of the disconnected cell 21a. Thereby, when the disconnection cell 21a is re-conducted, the current flowing through the disconnection cell 21a can be suppressed, and deterioration of the assembled battery 10 can be suppressed.

  10 assembled battery, 11 positive line, 12 negative line, 13 inverter, 14 motor generator, 15 power split mechanism, 16 engine, 17 differential gear, 18 wheels, 19 ignition switch, 20, 30, 40, 50 cell block, 20a disconnection Cell block, 21, 31, 41, 51 cell (normal cell), 21a disconnection cell, 22 positive electrode, 23 negative electrode, 24, 34, 44, 54 positive parallel bus bar, 24a, 27a opening, 25 positive connection bus bar, 26 negative connection Bus bar, 26a Broken part, 26b Re-welded part, 27, 37, 47, 57 Negative parallel bus bar, 28, 29 Tip, 61, 64, 65, 66, 67 Voltage sensor, 62 Current sensor, 63 Temperature sensor, 70 Control part , 71 CPU, 72 Memory, 73 Sensor / Equipment Centers face, 74 data bus, 90 connector, 100 electric vehicle.

Claims (1)

A charge / discharge control method for an assembled battery in which cell blocks in which a plurality of cells are connected in parallel are connected in series,
When there is a normal cell block in which all the cells are connected in parallel with the parallel connection line, and a disconnected cell block including a disconnected cell in which the parallel connection line is disconnected,
Based on the reduction of the voltage difference between the first open voltage of the normal cell block and the second open voltage of the disconnected cell block when charging and discharging the assembled battery, the charge rate of the disconnected cell is estimated,
Charging and discharging the assembled battery so that the charging rate of the assembled battery is within a predetermined control range centered on the estimated charging rate of the disconnected cell;
A charge / discharge control method for an assembled battery.

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