JP2007330021A - Capacity regulator for battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To regulate the capacities of cells without computing a variation among cells in the capacity or an amount of capacity regulation. <P>SOLUTION: Cell controllers CC1 to CCt having a capacity regulation circuit regulate the capacities of a predetermined number of cells among multiple cells so that the voltage of the predetermined number of cells becomes equal to a target voltage. Each of the cell controllers CC1 to CCt regulates the capacity of at least one of the predetermined number of cells redundantly with other cell controllers. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus for adjusting capacity (remaining capacity) between a plurality of cells constituting an assembled battery.

  Conventionally, the open circuit voltage of a plurality of cells constituting an assembled battery is detected, the voltage variation amount is obtained, the discharge required amount of each cell is calculated based on the obtained voltage variation amount, and each cell is discharged. Thus, an apparatus for making the capacity between cells (remaining capacity) uniform is known (see Patent Document 1).

JP-A-10-322925

  However, the conventional capacity adjusting device has a problem that it is necessary to calculate the voltage variation amount and the discharge required amount of each cell in order to make the capacity between the cells uniform.

  The capacity adjustment apparatus for an assembled battery according to the present invention includes a plurality of capacity adjustments for adjusting the capacity of a predetermined number of cells so that the remaining capacity of the predetermined number of cells is uniform among the plurality of cells constituting the assembled battery. A plurality of capacity adjustment circuits each performing capacity adjustment by overlapping at least one cell of a predetermined number of cells with another capacity adjustment circuit.

  According to the capacity adjustment device for an assembled battery according to the present invention, the capacity adjustment between cells can be performed without calculating the capacity variation amount and the capacity adjustment amount between a plurality of cells constituting the assembled battery.

  FIG. 1 is a diagram illustrating a configuration of an assembled battery capacity adjustment device according to an embodiment. The assembled battery 100 is configured by connecting in series n chargeable / dischargeable cells (n is a natural number) C1 to Cn. Each of the cell controllers CC1 to CCt (t is a natural number) has a capacity adjustment circuit therein, and adjusts the capacity of a predetermined number of cells. Here, each of the cell controllers CC1 to CCt adjusts the capacity of four cells. In addition, one of the four cells whose capacity is adjusted by one cell controller is a capacity adjustment target cell of another cell controller. In addition, the capacity | capacitance in a present Example represents remaining capacity (SOC), and is only described as a capacity | capacitance below.

  Specifically, the cell controller CC1 adjusts the capacity of the cells C1 to C4, and the cell controller CC2 adjacent to the cell controller CC1 adjusts the capacity of the cells C4 to C7. Accordingly, the cell C4 is a capacity adjustment target cell of the two cell controllers CC1 and CC2. The cell controller CC3 adjacent to the cell controller CC2 adjusts the capacity of the cells C7 to C10. Therefore, the cell C7 is a capacity adjustment target cell of the two cell controllers CC2 and CC3. Further, the cell controller CC4 adjacent to the cell controller CC3 adjusts the capacity of the cells C10 to C13. Hereinafter, similarly, four cells are capacity adjustment target cells of one cell controller, and one of the four cells is a capacity adjustment target cell of another adjacent cell controller. Yes.

  That is, the cells C1 to C4 constitute a capacity adjustment target cell group M1 whose capacity is adjusted by the cell controller CC1, and the cells C4 to C7 constitute a capacity adjustment target cell group M2 whose capacity is adjusted by the cell controller CC2. Yes. Hereinafter, similarly, the cell controller CC3 configures a capacity adjustment target cell group M3 whose capacity is adjusted by the cells C7 to C10, and the cell controller CC3 adjusts the capacity adjustment target cell group M4 whose capacity is adjusted by the cells C10 to C13. It is composed.

  FIG. 2 is a diagram showing a detailed configuration inside cell controllers CC1 and CC2. The cell controller CC1 includes resistors R1 to R4a, switches S1 to S4a, comparators (comparators) CP1 to CP4a, and a target voltage output circuit B1. The resistors R1 to R4a, the switches S1 to S4a, the comparators (comparators) CP1 to CP4a, and the target voltage output circuit B1 constitute a capacitance adjusting circuit for making the capacitances of the cells C1 to C4 uniform. Note that the switches S1 to S4 are transistors, for example.

  A circuit in which a resistor R1 and a switch S1 are connected in series is connected in parallel to the cell C1. Similarly, the circuits in which the resistors R2 to R4a and the switches S2 to S4a are connected in series are connected in parallel to the other cells C2 to C4.

  The target voltage output circuit B1 outputs the voltage having the lowest value among the cell voltages V1 to V4 of the cells C1 to C4 to the comparators CP1 to CP4a as the target voltage at the time of capacity adjustment. The target voltage output circuit B1 is composed of an analog circuit. Here, the capacity adjustment is performed when the assembled battery is not loaded (when charging / discharging is not performed). Therefore, the cell voltage is the no-load voltage (open voltage). In the example, the cell voltage is simply described for simplicity.

  The comparators CP1 to CP4a compare the target voltage (the lowest voltage among the cell voltages V1 to V4) output from the target voltage output circuit B1 with the cell voltages V1 to V4 of the cells C1 to C4, respectively. When the voltage is higher than the target voltage, a signal for turning on the corresponding switches S1 to S4 is output. For example, if the voltage V2 of the cell C2 is higher than the target voltage, a signal for turning on the switch S2 is output. When the switch S2 is turned on, a discharge current flows from the cell C2 via the resistor R2. With such a configuration, voltage adjustment is performed so that the voltages of the cells C1 to C4 coincide with the target voltage.

  The cell controller CC2 includes resistors R4b to R7a, switches S4b to S7a, comparators (comparators) CP4b to CP7a, and a target voltage output circuit B2. The resistors R4b to R7a, the switches S4b to S7a, the comparators (comparators) CP4b to CP7a, and the target voltage output circuit B2 constitute a capacitance adjusting circuit for making the capacitances of the cells C4 to C7 uniform.

  The circuit in which the resistor R4b and the switch S4b are connected in series is connected in parallel with the cell C4. Similarly, the circuits in which the resistors R5 to R7a and the switches S5 to S7a are connected in series are connected in parallel to the other cells C5 to C7.

  The target voltage output circuit B2 outputs the voltage having the lowest value among the cell voltages V4 to V7 of the cells C4 to C7 to the comparators CP4b to CP7a as the target voltage at the time of capacity adjustment. Similarly to the target voltage output circuit B1, the target voltage output circuit B2 is configured by an analog circuit instead of a CPU. The operations of the comparators CP4b to CP7a are the same as the operations of the comparators CP1 to CP4a. That is, by turning on a switch provided corresponding to a cell whose cell voltage is higher than the target voltage output from the target voltage output circuit B2, the cells whose cell voltage is higher than the target voltage are discharged, and each cell C4 is discharged. The voltage of ~ C7 is made uniform.

  Note that the cell controllers CC3 to CCt have the same configuration as that described above, and a description thereof will be omitted.

  3-6 is a figure which shows the voltage change of each cell, when the capacity | capacitance adjustment between cells is performed using the capacity adjustment apparatus of the assembled battery in one Embodiment. Here, it is assumed that the assembled battery 100 includes 22 cells C1 to C22. FIG. 3 shows the voltage value of each cell before capacity adjustment.

  As described above, each of the cell controllers CC1 to CC7 discharges other cells using the voltage of the cell having the lowest voltage value among the four managed cells as the target voltage. When the voltage of each cell before capacity adjustment is as shown in FIG. 3, for example, the cell controller CC1 uses the voltage value of the cell C2 having the lowest voltage value among the cells C1 to C4 as the target voltage, and the cells C1, C3, C4 is discharged. The cell controller CC2 discharges the cells C4, C5, and C7 using the voltage value of the cell C6 having the lowest voltage value among the cells C4 to C7 as a target voltage. FIG. 4 is a diagram showing the cell voltage after discharging each cell with the voltage of the cell having the lowest voltage value among the four cells managed by each cell controller CC1 to CC7 as the target voltage. is there.

  Each of the cell controllers CC1 to CC7 again discharges each cell with the voltage of the cell having the lowest voltage value among the four cells being managed as the target voltage. When the voltage of each cell is as shown in FIG. 4, for example, the cell controller CC1 uses the voltage value of the cell C4 having the lowest voltage value among the cells C1 to C4 as the target voltage, and the cells C1, C2, C3 Discharge. The cell controller CC2 discharges the cells C4, C5, and C6 using the voltage value of the cell C7 having the lowest voltage value among the cells C4 to C7 as a target voltage. FIG. 5 is a diagram illustrating the cell voltage after the second capacity adjustment is performed by each of the cell controllers CC1 to CC7.

  Thereafter, each of the cell controllers CC1 to CC7 repeatedly performs a process of discharging each cell using the voltage of the cell having the lowest voltage value among the four managed cells as the target voltage. FIG. 6 is a diagram illustrating the cell voltage when the above-described capacity adjustment processing is repeatedly performed and the voltage of each cell becomes uniform. By repeatedly performing the capacity adjustment process described above, the voltage of each cell is adjusted to the voltage of the cell C10 having the lowest voltage before the capacity adjustment.

  That is, each of the cell controllers CC1 to CCt adjusts the capacity between the cells so that the voltage of the four managed cells becomes the lowest cell voltage among the four cells. Since one of the cells is a capacity adjustment target cell of another cell controller, the voltage of all the cells can be made uniform by repeatedly performing the capacity adjustment.

  According to the assembled battery capacity adjustment device in one embodiment, each of the cell controllers CC1 to CCt including the capacity adjustment circuit has a predetermined number of cells remaining among the plurality of cells C1 to Cn constituting the assembled battery 100. The capacity of the predetermined number of cells is adjusted so that the capacities are uniform, and each of the cell controllers CC1 to CCt has at least one cell of the predetermined number of cells overlapping with other cell controllers. Make adjustments. Thereby, the capacity | capacitance adjustment between cells can be performed, without calculating the voltage variation amount between several cells C1-Cn which comprises the assembled battery 100, or a capacity | capacitance adjustment amount. Since it is not necessary to provide an IC or a CPU for calculating the amount of voltage variation between cells or the amount of capacity adjustment, the cost of the capacity adjustment device as a whole can be reduced. Further, the voltages of all the cells can be made uniform without performing data communication between the cell controllers CC1 to CCt or between the cell controller and another controller.

  In particular, according to the battery pack capacity adjustment device in one embodiment, capacity adjustment is performed using the lowest cell voltage among a predetermined number of cells as a target voltage, so that the voltage of each cell constitutes battery pack 100. It can be adjusted to the lowest cell voltage among all the cells C1 to Cn.

  The present invention is not limited to the embodiment described above. For example, the temperature sensor 200 may be provided in each of the cell controllers CC1 to CCt to detect the temperature of the capacity adjustment circuit, and the capacity adjustment may not be performed when the detected temperature is higher than a predetermined temperature Tth. At the time of cell capacity adjustment, since the discharge current flows through the resistors R1 to Rn provided corresponding to the cells C1 to Cn, the heat generation amount increases and the temperature rises. Thus, further temperature rise can be suppressed.

  FIG. 7 is a diagram illustrating a configuration in which the switch S1 is turned off when the temperature of the capacitance adjustment circuit detected by the temperature sensor 200 is higher than the predetermined temperature Tth inside the cell controller CC1. The comparator CP1 outputs an H level signal if the voltage V1 of the cell C1 is higher than the target voltage output from the target voltage output circuit B1, and outputs an L level signal if the cell voltage V1 is lower than the target voltage. To do. Note that an H level signal means a state in which current flows, and an L level signal means a state in which no current flows. The comparator 300 outputs an L level signal if the temperature detected by the temperature sensor 200 is higher than a predetermined temperature Tth, and outputs an H level signal if the detected temperature is lower than the predetermined temperature Tth. The AND circuit 400 performs an AND operation based on the output value of the comparator CP1 and the output value of the comparator 300. The switch S1 is turned on when the output value of the AND circuit 400 is at the H level and turned off when the output value is at the L level. Therefore, when the temperature detected by the temperature sensor 200 is higher than the predetermined temperature Tth, the switch S1 is turned off regardless of the output value of the comparator CP1. Although FIG. 7 shows a configuration diagram for turning off the switch S1, the configuration for turning off the other switches S2 to Sn is the same. Thereby, when the temperature of the capacity adjustment circuit is higher than the predetermined temperature Tth, it is possible to prevent the capacity adjustment.

  In the above-described embodiment, the lowest cell voltage among the four cells managed by the cell controllers CC1 to CCt is set as the target voltage so that the voltage of each cell becomes the target voltage. However, the average voltage of the four cells managed by each cell controller CC1 to CCt can be set as the target voltage. In the method of setting the average voltage of the four cells as the target voltage, the time required for making the voltages of all the cells uniform is longer than in the method of setting the lowest voltage among the four cells as the target voltage. The configuration of the target voltage output circuits B1 to Bt that output the average voltage of the four cells as the target voltage can be simplified. In addition to the minimum voltage and the average voltage, a voltage value based on the voltage of a predetermined number of capacity adjustment target cells may be set as the target voltage. Furthermore, in the capacity adjustment between cells, the remaining capacity of a predetermined number of cells only needs to be uniform. Therefore, the capacity adjustment method is not limited to the method in which the voltage of each cell is set to the target voltage.

  In the above-described embodiment, an example in which the capacity adjustment circuit provided in the cell controller adjusts the capacity of four cells has been described. However, the number of target cells in which one capacity adjustment circuit performs capacity adjustment is four. It is not limited and may be 3 or less, or 5 or more.

  In the embodiment described above, for example, the cell C4 is a capacity adjustment target cell of the cell controller CC1 and also a capacity adjustment target cell of the cell controller CC2 adjacent to the cell controller CC1, but one cell On the other hand, cell controllers that perform capacity adjustment in an overlapping manner are not limited to adjacent ones. Further, the number of cells for which capacity adjustment is performed in duplicate is not limited to one, and may be two or three or more.

  The above-described battery pack capacity adjustment device can be applied to a vehicle system such as an electric vehicle or a hybrid vehicle, or a system other than a vehicle. When applied to a vehicle system, the capacity adjustment of each cell can be performed not only when the vehicle is running, but also when the vehicle is stopped.

  The correspondence between the constituent elements of the claims and the constituent elements of the embodiment is as follows. That is, the cell controllers CC1 to CCt constitute a capacity adjustment circuit, the target voltage output circuits B1 to Bt constitute a target voltage setting circuit, and the temperature sensor 200 constitutes a temperature detection means. In addition, the above description is an example to the last, and when interpreting invention, it is not limited to the correspondence of the component of said embodiment and the component of this invention at all.

The figure which shows the structure of the capacity adjustment apparatus of the assembled battery in one embodiment The figure which shows the detailed structure inside cell controller CC1 and CC2. The figure which shows the voltage value of each cell before performing capacity adjustment The figure which shows the voltage value of each cell after performing capacity | capacitance adjustment of the 1st time by each cell controller. The figure which shows the voltage value of each cell after performing capacity | capacitance adjustment of the 2nd time by each cell controller. The figure which shows cell voltage when capacity adjustment is done repeatedly and the voltage of each cell becomes uniform The figure which shows the structure which turns off switch S1, when the temperature of the capacity | capacitance adjustment circuit detected by a temperature sensor is higher than predetermined temperature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Battery pack, 200 ... Temperature sensor, 300 ... Comparator, 400 ... AND circuit, B1-Bt ... Target voltage output circuit, C1-Cn ... Cell, CP1-CPn ... Comparator, R1-Rn ... Resistance, S1- Sn ... switch

Claims (5)

In a capacity adjustment device for an assembled battery that performs capacity adjustment between a plurality of cells constituting the assembled battery,
A plurality of capacity adjustment circuits for adjusting the capacity of the predetermined number of cells so that the remaining capacity of the predetermined number of cells is uniform among the plurality of cells;
Each of the plurality of capacity adjustment circuits adjusts the capacity of at least one cell of the predetermined number of cells by overlapping with another capacity adjustment circuit. The capacity adjustment apparatus for an assembled battery according to claim 1,
Each capacity adjustment circuit adjusts the voltage of a predetermined number of cells for capacity adjustment to be uniform, thereby making the remaining capacity of the predetermined number of cells uniform. . The capacity adjustment device for an assembled battery according to claim 2,
Each capacity adjustment circuit adjusts so that the voltage of the predetermined number of cells becomes the lowest cell voltage among the predetermined number of cells. The capacity adjustment device for an assembled battery according to claim 2,
Each capacity adjustment circuit adjusts so that the voltage of the predetermined number of cells becomes an average voltage of the predetermined number of cells. In the capacity adjustment apparatus of the assembled battery as described in any one of Claims 1-4,
Temperature detecting means for detecting the temperature of the capacitance adjusting circuit;
The capacity adjustment circuit according to claim 1, wherein the capacity adjustment circuit does not adjust the capacity of the cell when the temperature detected by the temperature detection means is equal to or higher than a predetermined temperature.

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