JP2011223653A - Voltage regulation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a difference in voltage value between battery cells while simplifying the configuration of a circuit for regulating voltage values of a plurality of battery cells connected in series.SOLUTION: A voltage regulation system 1 has switches SW1-SW4, SW11-SW15 and a control unit. A detection section 8 of the control unit 6 detects voltage values Va-Vd of cells Ca-Cd. A determination section 9 determines whether a start condition and an end condition are established. When a difference ΔV between a maximum voltage value and a minimum voltage value calculated based on the voltage values Va-Vd exceeds a first predetermined voltage value Vx, the start condition is established and when that difference is less than or equal to a second predetermined voltage value Vy, the end condition is established. From the establishment of the start condition to the establishment of the end condition, a control section 10 determines one combination subjected to processing from among predetermined three combinations in accordance with a predetermined order and performs regulation processing on the determined combination, respectively.

Description

  The present invention relates to a voltage adjustment system that adjusts a difference in voltage value between a plurality of battery cells connected in series.

  Japanese Patent Application Laid-Open No. 2007-31335 discloses a case where, in a fuel cell having a plurality of cells, the voltage of each cell is periodically measured, and a performance-decreasing cell whose detected voltage is lower than a predetermined voltage is detected. A circuit connection control system is described that improves the performance of a fuel cell by connecting in parallel proximity cells adjacent to the degraded cell to the degraded cell.

JP 2007-31335 A

  In general, in an assembled battery in which a plurality of battery cells are connected in series to obtain a desired output, the capacity of the plurality of battery cells varies as charging and discharging are repeated. Small battery cells cause overcharging and overdischarging, resulting in deterioration of performance, leading to a decrease in chargeable / dischargeable capacity and a decrease in life of the entire assembled battery. For this reason, it is desirable to adjust so that the difference of the voltage value between several battery cells may reduce.

  However, in the control system described in Japanese Patent Application Laid-Open No. 2007-31335, for example, when the voltage value of the neighboring cell is also lowered, the voltage value of the performance-reduced cell is not sufficiently increased, so that the fuel cell is configured. It is not possible to reduce the voltage difference between the plurality of cells. In addition, since any cell constitutes a circuit that can be connected in parallel with neighboring cells, it is necessary to provide a large number of switches and connection lines, which complicates the control circuit.

  Therefore, the present invention provides a voltage adjustment system capable of reducing the difference in voltage values between a plurality of battery cells while simplifying the configuration of a circuit for adjusting the voltage values of the plurality of battery cells connected in series. With the goal.

  In order to achieve the above object, the present invention is a voltage adjustment system that adjusts a difference in voltage value between a plurality of battery cells connected in series, and includes a plurality of adjustment circuits, a plurality of switches, detection means, and a first determination. Means, second determination means, and control means.

  The plurality of adjustment circuits are respectively provided corresponding to a predetermined plurality of combinations among all combinations of two battery cells extracted from the plurality of battery cells, and two battery cells constituting each combination Are connected in a parallel state in which the same polarity of the two battery cells are energized. The plurality of switches are provided corresponding to each of the predetermined plurality of combinations, and are selectively set to the normal position and the adjustment position. The switch at the normal position shuts off each of the plurality of adjustment circuits, and the switch at the adjustment position connects the adjustment circuit.

  The detection means detects each voltage value of the plurality of battery cells. The first determination unit determines that the start condition is satisfied when there are two battery cells in which a difference between the voltage values detected by the detection unit exceeds a preset first predetermined voltage value. The second determination means determines that the termination condition is satisfied when there is no two battery cells in which the difference between the voltage values detected by the detection means exceeds the second predetermined voltage value set in advance below the first predetermined voltage value. Is determined. When the first determination unit determines that the start condition is satisfied, the control unit determines one combination as a processing target from the plurality of predetermined combinations, and the processing target among the plurality of switches is determined. When the end condition is satisfied, the second determination means determines that the adjustment process for continuously setting only the switch corresponding to the combination to the adjustment position until the voltage values of the two battery cells constituting the combination are averaged is established. Until the determination is made, the combination of the processing targets is changed and repeated according to a preset order.

  In the above configuration, the first determination unit determines that the start condition is satisfied when there are two battery cells that have a voltage value difference exceeding the first predetermined voltage value. That is, it is determined that the start condition is satisfied when there is at least one combination of two battery cells having a voltage value difference exceeding the first predetermined voltage value. Similarly, the second determination unit determines that the termination condition is satisfied when there is no combination of two battery cells that have a difference in voltage value exceeding the second predetermined voltage value. When the first determination unit determines that the start condition is satisfied, the control unit determines and determines one combination as a processing target from a plurality of combinations set in advance according to a preset order. A first adjustment process is executed in which only the switch corresponding to the combination to be processed is set to the adjustment position. During or after execution of the first adjustment process, the second determination means determines whether or not the end condition is satisfied, and when it is determined that the end condition is not satisfied, the control means performs the first adjustment. If the process is being executed, the adjustment process is continued. If the first adjustment process is completed, the next combination to be processed is determined according to a preset order, and The second adjustment process is executed. On the other hand, when the second determination unit determines that the end condition is satisfied, the control unit does not shift to the second adjustment process when the first adjustment process is executed, and does not shift to the first adjustment process. If the adjustment process is being executed, the adjustment process is terminated halfway, or the adjustment process is not continued until the adjustment process is completed. As described above, the control unit performs processing from a plurality of predetermined combinations according to a predetermined order from when it is determined that the start condition is satisfied until when it is determined that the end condition is satisfied. One combination is determined, and adjustment processing is executed for each determined combination.

  As described above, since a combination to be processed is determined from predetermined combinations set regardless of the state of each battery cell and each adjustment process is executed, complicated determination and control are not required. The difference in voltage value between all the battery cells can be reduced. In addition, since a series of processes for repeating each adjustment process is executed from when the start condition is satisfied until the end condition is satisfied, the difference in voltage values among all the battery cells can be reliably reduced. Furthermore, since a series of processing is terminated when it is determined that the termination condition is satisfied, the time required for all the adjustment processing can be shortened and unnecessary power consumption due to the adjustment processing is suppressed. can do. Further, in each adjustment process, the control means continuously performs the adjustment process until the voltage values of the two battery cells constituting the combination to be processed are averaged, so that the voltage values of these two battery cells are reliably determined. Can be averaged. Furthermore, since the adjustment process is terminated when the two battery cells are averaged, the time required for each adjustment process can be shortened.

  Further, the plurality of predetermined combinations may be all combinations except for a combination of two battery cells adjacently connected in series.

  Generally, in order to connect two battery cells connected in series in a parallel state, a switch that cuts off the serial connection and a connection line that connects the same polarity of each battery cell are necessary. That is, when forming an adjustment circuit corresponding to all combinations of two battery cells extracted from a plurality of battery cells connected in series, one battery is connected between two battery cells adjacently connected in series. It is necessary to provide a connection line connected to the negative electrode of the cell, a connection line connected to the positive electrode of the other battery cell, and a switch.

  On the other hand, in the above configuration, among all combinations of two battery cells extracted from the plurality of battery cells, a plurality corresponding to all combinations excluding the combination of two battery cells adjacently connected in series. The adjustment circuit is provided. In this case, a connection line and a switch that are commonly connected to both the negative electrode of one battery cell and the positive electrode of the other battery cell are provided between two adjacent battery cells connected in series. It is possible to disconnect the connection and connect two battery cells in parallel. Therefore, the circuit configuration can be simplified. In addition, all the plurality of battery cells connected in series are all of the combinations of two battery cells extracted from the plurality of battery cells, except for the combination of two battery cells connected in series adjacent to each other. Since it belongs to one of the combinations, the adjustment process can be executed for all the battery cells.

  The second predetermined voltage value may be less than the first predetermined voltage value.

  In the above configuration, since the second predetermined voltage value is set to be less than the first predetermined voltage value, the start condition is not satisfied immediately after the end condition is satisfied. Therefore, the execution frequency of a series of adjustment processes can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the difference of the voltage value between several battery cells can be reduced, simplifying the structure of the circuit which adjusts the voltage value of several battery cells connected in series.

It is a lineblock diagram of the voltage regulation system of one embodiment. It is a flowchart which shows the voltage adjustment process of one Embodiment. It is a figure which shows transition of voltage value Va-Vd of cell Ca-Cd at the time of performing the adjustment process 5 times.

  Hereinafter, a voltage regulation system according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the voltage adjustment system 1 adjusts a difference in voltage value between a plurality of battery cells (secondary battery cells) Ca to Cd, and is mounted on the vehicle together with the battery cells Ca to Cd. . The battery cells Ca to Cd are connected in series, and supply power to the load circuit 2 such as a vehicle driving motor or an in-vehicle electrical component as a secondary battery. The battery cells Ca to Cd may be connected to a charging circuit 3 such as a generator, and the motor may be a motor generator having both power generation functions.

  As shown in FIG. 1, in this embodiment, four battery cells Ca to Cd are mounted on a vehicle, and the voltage adjustment system 1 includes a battery side switch group 4, an adjustment side switch group 5, and a control unit 6. . The battery side switch group 4 has four switches SW1 to SW4, and the adjustment side switch group 5 has five switches SW11 to SW15. In the following description, the battery cell is simply abbreviated as a cell. The predetermined combinations are all combinations excluding the combination of two battery cells adjacently connected in series, the combination of cell Ca and cell Cc, the combination of cell Cb and cell Cd, and the cell There are three combinations of Ca and cell Cd. The order of determining one combination to be processed in each adjustment process from these three combinations is firstly the combination of cell Ca and cell Cc, second is the combination of cell Cb and cell Cd, A combination of cell Ca and cell Cd. Further, the second predetermined voltage value Vy is less than the first predetermined voltage value Vx.

  The switches SW1 to SW4 of the battery side switch group 4 have two contact points, and can be set to any one of a connection position for connecting the two contact points and a neutral position for blocking between the two contact points. Switch.

  The switches SW1 to SW4 are provided on the negative electrode sides of the cells Ca to Cd, respectively. The switch SW1 connects and disconnects the negative electrode of the cell Ca and the positive electrode of the cell Cb, and connects and disconnects the negative electrode of the cell Ca and the switch SW12. The switch SW2 connects and disconnects between the negative electrode of the cell Cb and the positive electrode of the cell Cc, and connects and disconnects the negative electrode of the cell Cb and the switch SW13. The switch SW3 connects and disconnects the negative electrode of the cell Cc and the positive electrode of the cell Cd, and connects and disconnects the negative electrode of the cell Cc and the switch SW14. The switch SW4 connects and disconnects the negative electrode of the cell Cd and the switch SW15.

  When the switches SW1 to SW4 are all set to the connection position (two contacts are connected), the cells Ca to Cd are connected in series. On the other hand, when any of the switches SW1 to SW4 is set to the neutral position, the series connection between the cells Ca to Cd is cut off. Accordingly, the switches SW1 to SW4 in the normal state in which the cells Ca to Cd are discharged and charged with the motor, the generator, and the like and the voltage adjustment process described later is not executed are connected by the control unit 6. Set and maintained in position. In addition, during the voltage adjustment process, the switch that does not correspond to the combination of the two cells to be processed among the switches SW1 to SW4 is set to the neutral position by the control unit 6.

  The switches SW11 to SW15 of the adjustment-side switch group 5 have a basic contact, a first contact, and a second contact, a first connection position for connecting the basic contact to the first contact, and a basic contact to the second contact. This is a three-way switch that can be set to any one of a second connection position to be set and a neutral position in which the basic contact is not connected to either the first contact or the second contact.

  The basic contact 11a of the switch SW11 is connected to the positive electrode of the cell Ca. The basic contact 12a of the switch SW12 is connected to the negative electrode of the cell Ca and the positive electrode of the cell Cb through the switch SW1. The basic contact 13a of the switch SW13 is connected to the negative electrode of the cell Cb via the switch SW2 and to the positive electrode of the cell Cc. The basic contact 14a of the switch SW14 is connected to the negative electrode of the cell Cc via the switch SW3 and to the positive electrode of the cell Cd. The basic contact 15a of the switch SW15 is connected to the negative electrode of the cell Cd through the switch SW4. The first contacts 11b to 15b of the switches SW11 to SW15 are connected to the first connection line 12, respectively, and the second contacts 11c to 15c are connected to the second connection line 13, respectively. The switches SW11 to SW15 in the normal state in which voltage adjustment processing described later is not executed are set and maintained at the neutral position by the control unit 6.

  The switch SW1 is set to the connection position (two contacts are connected), the switch SW3 is set to the connection position (two contacts are connected), and the switch SW11 is set to the first connection position (the basic contact 11a and the first contact). 1 contact 11b is connected), switch SW12 is set to the second connection position (basic contact 12a and second contact 12c are connected), and switch SW13 is set to the first connection position (basic contact 13a and first contact). When the switch SW14 is set to the second connection position (the basic contact 14a and the second contact 14c are connected) and the switch SW2 is set to the neutral position, the cell Ca and the cell Cc are connected. Are connected in a parallel state in which the same poles of both cells are energized. When there is a difference between the voltage values of the cell Ca and the cell Cc connected in parallel, the cell with the large voltage value is discharged to the small cell, the small cell is charged, and the voltage value between the cell Ca and the cell Cc is , Adjusted so as to approach the average voltage value of both cells. That is, the switch SW1 is in the connection position, the switch SW3 is in the connection position, the switch SW11 is in the first connection position, the switch SW12 is in the second connection position, the switch SW13 is in the first connection position, and the switch SW14 is in the second connection position. In addition, the circuit formed by setting the switch SW2 to the neutral position functions as an adjustment circuit corresponding to the combination of the cell Ca and the cell Cc, and the switch SW1, the switch SW3, the switch SW11, the switch SW12, SW13 and switch SW14 function as an adjustment switch corresponding to the combination of cell Ca and cell Cc. In this case, the connection position of the switch SW1, the connection position of the switch SW3, the first connection position of the switch SW11, the second connection position of the switch SW12, the first connection position of the switch SW13, and the second connection position of the switch SW14 This is an adjustment position at which the adjustment circuit corresponding to the combination of Ca and cell Cc functions. Also, for the combination of the cell Cb and the cell Cd and the combination of the cell Ca and the cell Cd, an adjustment circuit corresponding to the combination of the cell Ca and the cell Cc can be formed, and a switch that functions as an adjustment switch and its adjustment The position is determined.

  Note that the adjustment circuits corresponding to these three combinations each composed of two cells can be formed by two different paths. For example, among the adjustment switches corresponding to the combination of the cell Ca and the cell Cc, the adjustment positions of the switch SW11 and the switch SW13 are switched from the first connection position to the second connection position (basic contacts 11a and 13a and the second contact 11c. , 13c are respectively connected), and the adjustment positions of the switch SW12 and the switch SW14 are switched from the second connection position to the first connection position (the basic contacts 12a, 14a and the first contacts 12b, 14b are respectively connected). ), The cell Ca and the cell Cc are connected in parallel. That is, the switch SW1 and the switch SW3 are set to the connection position, the switch SW11 and the switch SW13 are set to the second connection position, the switch SW12 and the switch SW14 are set to the first connection position, and the switch SW2 is set to the neutral position. The circuit also functions as an adjustment circuit corresponding to the combination of the cell Ca and the cell Cc.

  The control unit 6 includes a CPU (Central Processing Unit) 7 and a storage unit 11. The storage unit 11 is configured by a recording medium such as a ROM (Read Only Memory) or a RAM (Random Access Memory).

  The storage unit 11 stores a voltage adjustment process execution program. The CPU 7 functions as the detection unit 8, the determination unit 9, and the control unit 10 by executing the voltage adjustment process according to the voltage adjustment process execution program. In addition, the storage unit 11 sequentially updates and stores the voltage values of the cells Ca to Cd and three predetermined combinations (the combination of the cell Ca and the cell Cc, the cell Cb and the cell Cd The adjustment switch corresponding to the combination, the combination of the cell Ca and the cell Cd) and the adjustment switch setting table in which the adjustment position is set in advance are stored. As described above, since the adjustment circuit corresponding to these three combinations can be formed by two different paths, any one of these two paths is selected in advance in the adjustment switch setting table, An adjustment switch and an adjustment position for functioning the adjustment circuit formed by the path are set. Further, the adjustment switch and the adjustment position corresponding to each combination are set in the order of the combinations to be processed in each adjustment process. In the adjustment switch setting table according to the present embodiment, the adjustment switch and the adjustment position corresponding to the combination of the cell Ca and the cell Cc in the first order, the adjustment switch corresponding to the combination of the cell Cb and the cell Cd in the second order, and An adjustment switch and an adjustment position corresponding to the combination of the cell Ca and the cell Cd in the third order are set, and the switch SW1 (adjustment) is set as an adjustment switch and an adjustment position corresponding to the combination of the cell Ca and the cell Cc. Position: connection position), switch SW3 (adjustment position: connection position), switch SW11 (adjustment position: first connection position), switch SW12 (adjustment position: second connection position), switch SW13 (adjustment position: first connection position) ) And switch SW14 (adjustment position: second connection position).

  The detection unit 8 detects the voltage values Va to Vd of the cells Ca to Cd, and sequentially updates and stores the detected voltage values Va to Vd in the voltage value storage table of the storage unit 11.

  The determination unit 9 includes a first determination unit and a second determination unit. The first determination unit calculates a difference ΔV between the maximum voltage value and the minimum voltage value among the voltage values Va to Vd detected by the detection unit 8, and the difference ΔV between the calculated voltage values is a first predetermined value. It is determined whether the voltage value Vx is exceeded (whether there are two cells in which the difference between the voltage values exceeds the first predetermined voltage value Vx). When the first determination unit determines that the voltage value difference ΔV exceeds the first predetermined voltage value Vx (there are two cells in which the difference between the voltage values exceeds the first predetermined voltage value Vx), It is determined that the start condition is satisfied. The second determination unit calculates a difference ΔV between the maximum voltage value and the minimum voltage value among the voltage values Va to Vd detected by the detection unit 8, and the difference ΔV between the calculated voltage values is a second predetermined value. It is determined whether the voltage value Vy is exceeded (whether there are two battery cells in which the difference between the voltage values exceeds the second predetermined voltage value Vy). When the second determination unit determines that the voltage value difference ΔV is equal to or smaller than the second predetermined voltage value Vy (there is no two battery cells in which the difference between the voltage values exceeds the second predetermined voltage value Vy), It is determined that the end condition is satisfied.

  When the determination unit 9 determines that the start condition is satisfied, the control unit 10 determines a combination to be processed from predetermined three combinations according to a preset order, and the combination is determined for the combination. Execute the adjustment process. The controller 10 refers to the adjustment switch setting table, sets the adjustment switch corresponding to the combination of the cell Ca and the cell Cc set in the first order to the adjustment position, and sets the adjustment switch to the combination of the cell Ca and the cell Cc. The corresponding adjustment circuit is caused to function (first adjustment process). The control unit 10 determines whether or not the voltage values of the cells Ca and Cc are averaged, and when determining that the voltage values are averaged, the control unit 10 returns the switch set to the adjustment position to the normal position. When the determination unit 9 determines that the end condition is not satisfied after the end of the first adjustment process, the control unit 10 refers to the adjustment switch setting table and sets the cell Cb and the cell set in the second order. A second adjustment process is executed in which the adjustment switch corresponding to the combination of Cd is set to the adjustment position. The control unit 10 determines the preset order (first order: combination of cell Ca and cell Cc, second order: cell Cb and cell Cd) until the determination unit 9 determines that the end condition is satisfied. , Third order: combination of cell Ca and cell Cd), the combination of processing targets is changed and each adjustment process is repeatedly executed (the third adjustment process (the combination of cells Ca and Cd is set as the processing target). Adjustment process), the fourth adjustment process (adjustment process for which the combination of the cells Ca and Cc is processed), the fifth adjustment process (adjustment process for which the combination of the cells Cb and Cd is processed), -Nth adjustment process). When the determination unit 9 determines that the end condition is satisfied, the control unit 10 does not proceed to the next adjustment process, but ends a series of processes that repeat each adjustment process.

  Note that a method for determining that the voltage values of two cells connected in parallel in each adjustment process are averaged is not particularly limited. For example, the voltage values of two cells are sequentially detected and 2 2 A method of determining that the difference between the two voltage values is equal to or less than a reference voltage value Vz (Vz ≦ Vy) set to be equal to or less than the second predetermined voltage value Vy, and a current value of a connected adjustment circuit is measured. , A method for determining that the measured current value is averaged when it is equal to or less than a predetermined reference current value, and setting and calculating the time required for averaging the voltage value as a reference time, and measuring the elapsed time of the adjustment process, Various methods such as a method of determining that the measured elapsed time has been averaged when it reaches the reference time can be applied.

  Hereinafter, the voltage adjustment process executed by the CPU 7 will be described with reference to the flowchart of FIG. This process is started on the condition that the cells Ca to Cd are not charged or discharged, such as when the vehicle is stopped, and is executed every predetermined time. Also, it is executed on condition that each adjustment process is not being executed. Hereinafter, the voltage values Va to Vd of the cells Ca to Cd will be described assuming that Va> Vc> Vd> Vb.

  When the process is started, the detection unit 8 detects the voltage values Va to Vd of the cells Ca to Cd, and stores the detected voltage values Va to Vd in the storage unit 11 (step S1).

  Next, the determination unit 9 determines whether a start condition is satisfied (step S2). Specifically, the voltage values Va to Vd are read from the storage unit 11, the difference between the maximum voltage value and the minimum voltage value (ΔV = Va−Vb) is calculated, and the calculated voltage value difference ΔV Whether or not exceeds the first predetermined voltage value Vx.

  When the voltage value difference ΔV exceeds the first predetermined voltage value Vx (ΔV> Vx), it is determined that the start condition is satisfied (step S2: YES), and the control unit 10 performs the first adjustment process. Is executed (step S3). The control unit 10 refers to the adjustment switch setting table, sets the adjustment switch corresponding to the combination of the cell Ca and the cell Cc set in the first order to the adjustment position, and arranges the cell Ca and the cell Cc in parallel. Make the adjustment circuit connected to the state work. Specifically, the switch SW1 is set (maintained) at the connection position, the switch SW3 is set (maintains) at the connection position, the switches SW11 and SW13 are set at the first connection position, the switches SW12 and SW14, Is set to the second connection position, and the switch SW2 and the switch SW4 (switches that do not correspond to the combination of the cell Ca and the cell Cc among the switches SW1 to SW4) are set to the neutral position. The control unit 10 determines whether or not the voltage values of the cell Ca and the cell Cc are averaged. When the control unit 10 determines that the voltage values are averaged, the switch SW1, the switch SW3, and the switches SW11 to SW14 are moved from the adjustment position to the normal position. The switch SW2 and the switch SW4 are returned from the neutral position to the normal position.

  Subsequently, the detection unit 8 detects the voltage values Va to Vd of the cells Ca to Cd, and updates the voltage values Va to Vd stored in the storage unit 11 (step S4).

  Next, the determination unit 9 determines whether or not an end condition is satisfied (step S5). Specifically, the voltage values Va to Vd are read from the storage unit 11 to calculate a difference ΔV between the maximum voltage value and the minimum voltage value, and the calculated difference ΔV is the second predetermined voltage value. It is determined whether or not Vy is exceeded.

  When the voltage value difference ΔV exceeds the second predetermined voltage value Vy (ΔV> Vy), it is determined that the termination condition is not satisfied (step S5: NO), and the control unit 10 determines that the cell Cb and the cell Cd A second adjustment process is performed with the combination of the two as a processing target (step S3).

  Subsequently, the detection unit 8 detects the voltage values Va to Vd of the cells Ca to Cd, and updates the voltage values Va to Vd of the storage unit 11 (step S4).

  The determination unit 9 determines whether or not an end condition is satisfied (step S5). When the voltage value difference ΔV is equal to or less than the second predetermined voltage value Vy (ΔV ≦ Vy), the end condition is satisfied. (Step S5: YES) and this process is terminated.

  Further, when the voltage value difference ΔV is equal to or smaller than the first predetermined voltage value Vx (ΔV ≦ Vx), the determination unit 9 determines that the start condition is not satisfied (step S2: NO), and the CPU 7 performs this process. Exit.

Next, the state of the voltage values Va to Vd of the cells Ca to Cd that execute the adjustment process will be described with reference to FIG. FIG. 3 is a diagram illustrating changes in the voltage values Va to Vd of the cells Ca to Cd when the adjustment process is performed five times. FIG. 3A is a diagram illustrating the voltage values Va to Vd of the cells Ca to Cd before execution of the first adjustment process. FIG. 3B is a diagram illustrating the voltage values Va ₂ , Vb, Vc ₂ , and Vd of the cells Ca to Cd after execution of the first adjustment process that targets the combination of the cell Ca and the cell Cc. FIG. 3C is a diagram illustrating the voltage values Va _{2 to} Vd ₂ of the cells Ca to Cd after execution of the second adjustment process with the combination of the cell Cb and the cell Cd as a processing target. FIG. 3D is a diagram illustrating the voltage values Va ₃ , Vb ₂ , Vc ₂ , and Vd ₃ of the cells Ca to Cd after execution of the third adjustment process for which the combination of the cell Ca and the cell Cd is a processing target. . FIG. 3E is a diagram illustrating the voltage values Va ₄ , Vb ₂ , Vc ₃ , and Vd ₃ of the cells Ca to Cd after execution of the fourth adjustment process for which the combination of the cell Ca and the cell Cc is a processing target. . FIG. 3F is a diagram illustrating the voltage values Va ₄ , Vb ₃ , Vc ₃ , Vd ₄ of the cells Ca to Cd after execution of the fifth adjustment process for which the combination of the cell Cb and the cell Cd is a processing target. . Each adjustment process is continuously executed until the voltage values of the two cells are completely averaged and equal.

  As shown in FIG. 3A, the voltage values Va to Vd of the cells Ca to Cd before executing the first adjustment process are Va> Vc> Vd> Vb. At this time, the voltage value difference ΔV1 = Va−Vb between the cell Ca and the cell Cb exceeds the first predetermined voltage value Vx (ΔV1> Vx), and the start condition is satisfied.

When the first adjustment process is executed, the cell Ca and the cell Cc are connected in parallel, the cell Ca having a large voltage value is discharged, and the cell Cc having a small voltage value is charged. That is, the voltage value Va of the cell Ca decreases, the voltage value Vc of the cell Cc increases, and the voltage values Va and Vc of the cells Ca and Cc are averaged. The voltage values Va ₂ and Vc ₂ of the cells Ca and Cc after execution of the first adjustment process are Va ₂ = Vc ₂ = (Va + Vc) / 2, and as shown in FIG. 3B, the cells Ca to Cd The voltage values Va ₂ , Vb, Vc ₂ , and Vd are Va ₂ = Vc ₂ >Vd> Vb. At this time, the voltage value difference ΔV2 = Va ₂ −Vb between the cell Ca and the cell Cb exceeds the second predetermined voltage value Vy (ΔV2> Vy), and the termination condition is not satisfied.

Subsequently, when the second adjustment process is executed, the cell Cb and the cell Cd are connected in parallel, and the voltage values Vb and Vd of the cells Cb and Cd are averaged. The voltage values Vb ₂ and Vd ₂ of the cells Cb and Cd after the second adjustment processing are executed are Vb ₂ = Vd ₂ = (Vb + Vd) / 2, and as shown in FIG. The voltage values Va _{2 to} Vd ₂ are Va ₂ = Vc ₂ > Vb ₂ = Vd ₂ . At this time, the voltage value difference ΔV3 = Va ₂ −Vb ₂ between the cell Ca and the cell Cb exceeds the second predetermined voltage value Vy (ΔV3> Vy), and the termination condition is not satisfied.

Subsequently, the voltage values Va ₃ and Vd ₃ of the cells Ca and Cd averaged by executing the third adjustment process are Va ₃ = Vd ₃ = (Va + Vb + Vc + Vd) / 4, and the fourth adjustment process is executed. Then, the voltage values Va ₄ and Vc ₃ of the cells Ca and Cc are Va ₄ = Vc ₃ = (3Va + Vb + 3Vc + Vd) / 8. Each voltage value of the cells Ca to Cd after execution of the third and fourth adjustment processes is as shown in FIGS. 3D and 3E, and the maximum voltage value and the minimum value among the voltage values of the cells Ca to Cd. The difference ΔV4, ΔV5 from the voltage value exceeds the second predetermined voltage value Vy (ΔV4> Vy, ΔV5> Vy), and the termination condition is not satisfied. When the fifth adjustment process is executed, the voltage values Vb ₃ and Vd ₄ of the cells Cb and Cd become Vb ₃ = Vd ₄ = (Va + 3Vb + Vc + 3Vd) / 8, and as shown in FIG. 3 (f), the cells Ca to Cd The voltage values Va ₄ , Vb ₃ , Vc ₃ , and Vd ₄ are Va ₄ = Vc ₃ > Vb ₃ = Vd ₄ . At this time, the voltage difference ΔV6 = Va ₄ −Vb ₃ between the cell Ca and the cell Cb becomes equal to or less than the second predetermined voltage value Vy (ΔV6 ≦ Vy), the end condition is satisfied, and the series of adjustment processing ends.

  The difference ΔV1 between the maximum voltage value and the minimum voltage value among the voltage values of the cells Ca to Cd before execution of the first adjustment process and after execution of the fifth adjustment process (shown in FIG. 3A). And ΔV6 (shown in FIG. 3F) are the following expressions (1) and (2), and ΔV1−ΔV6 is the following expression (3).

ΔV1 = Va−Vb (1)
ΔV6 = Va ₄ −Vb ₃
= (Va-Vb + Vc-Vd) / 4 (2)
ΔV1−ΔV6 = (3Va−3Vb−Vc + Vd) / 4
= {3 (Va−Vb) − (Vc−Vd)} / 4 (3)

  Since Va> Vc> Vd> Vb, Va−Vb> Vc−Vd, 3 (Va−Vb) − (Vc−Vd)> 0 in the above equation (3), and ΔV1−ΔV6> 0. It becomes. That is, the difference ΔV6 between the maximum voltage value and the minimum voltage value among the voltage values of the cells Ca to Cd after the fifth adjustment process is performed is based on the difference ΔV1 between the voltage values before the first adjustment process is performed. Since it is small ((DELTA) V1> (DELTA) V6), it turns out that the difference of voltage value Va-Vd between cell Ca-Cd reduces by performing adjustment processing 5 times.

  As described above, according to the voltage adjustment system of the present embodiment, it is possible to reduce the difference in voltage value between the battery cells while simplifying the configuration of the circuit for adjusting the voltage values of the plurality of battery cells connected in series. Can do.

  In the above embodiment, the determination unit 9 calculates the difference between the maximum voltage value and the minimum voltage value among the voltage values Va to Vd of the cells Ca to Cd, and the difference ΔV between the calculated voltage values is By determining whether or not the first predetermined voltage value Vx is exceeded, it is determined whether or not the start condition is satisfied, but is not limited to the above, and exceeds the first predetermined voltage value. Various methods can be applied as long as it is possible to determine whether or not there is at least one combination of two cells having a voltage value difference. For example, a method of extracting two voltage values from the voltage values Va to Vd and sequentially comparing the difference between the two voltage values with the first predetermined voltage value, or calculating an average value of the voltage values Va to Vd. A first upper limit voltage value obtained by adding a half value of the first predetermined voltage value to the calculated average value and a first lower limit voltage value obtained by subtraction, and a cell having a voltage value exceeding the first upper limit voltage value. And a method of determining whether or not a cell having a voltage value equal to or lower than the first lower limit voltage value exists at the same time. The same applies to determining the end condition.

  In the above embodiment, the determination unit 9 determines whether or not the end condition is satisfied after each adjustment process is executed. However, the determination unit 9 sequentially determines during the execution of each adjustment process and the end condition is satisfied. When the determination is made, the series of adjustment processes may be terminated. However, in each adjustment process, the voltage values of the two cells are averaged when the difference between the voltage values of the two cells is equal to or less than the reference voltage value Vz (Vz <Vy) set to be less than the second predetermined voltage value Vy. When it is determined that the adjustment processing has been completed, the adjustment processing may not be completed although the end condition of the series of adjustment processing is satisfied. In this case, when the end condition is satisfied, the adjustment process is terminated and the series of adjustment processes is terminated, or when the adjustment process is completed, the series of adjustment processes is terminated.

  Moreover, the form and arrangement | positioning of the circuit and switch which connect two cells which respectively comprise a predetermined several combination in a parallel state are not limited above.

  Further, the predetermined plurality of combinations are not limited to the above. For example, all combinations of two battery cells adjacently connected in series may be set as a predetermined combination. In this case, the circuit which forms each adjustment circuit respectively corresponding to all the combinations of two battery cells adjacently connected in series is comprised.

  Further, the number of battery cells connected in series is not limited to four, but may be two or three, or may be five or more.

  The adjustment switch setting table is not limited to the above. For example, an adjustment switch setting table in which adjustment switches and adjustment positions corresponding to the combinations are set in any order may be used. In this case, when the control unit 10 determines one combination to be processed in a preset order, the control unit 10 refers to the adjustment switch setting table and determines an adjustment switch and an adjustment position corresponding to the combination. Further, the adjustment switch setting table may be set with an adjustment switch and an adjustment position that function two paths that can be formed. In this case, before starting this process, the user selects one route from the two stored routes in advance.

  Further, the second predetermined voltage value Vy may be set to the same value as the first predetermined voltage value Vx. However, in this case, as compared with the case where the second predetermined voltage value Vy is set to be less than the first predetermined voltage value Vx as described above, the number of adjustment processes is the same or less, and the time required for all the adjustment processes is also reduced. Although it is the same or shorter, the possibility that the start condition is satisfied immediately increases when the cells Ca to Cd are discharged. As the second predetermined voltage value Vy is set smaller than the first predetermined voltage value Vx, the period from when the end condition is satisfied to when the start condition is satisfied becomes longer, and the frequency of execution of the adjustment process is reduced.

  The above-described embodiment is an example of the present invention and can be changed without departing from the present invention.

  The present invention is widely applicable to voltage adjustment between battery cells when a large number of battery cells are connected in series, such as a power source mounted on a hybrid vehicle or an electric vehicle.

1: Voltage adjustment system 2: Load circuit 3: Charging circuit 4: Battery side switch group 5: Adjustment side switch group 6: Control unit 7: CPU (Central Processing Unit)
8: Detection unit (detection means)
9: Determination unit (determination means)
10: Control unit (control means)
11: Storage unit 12, 13: Connection line Ca to Cd: Battery cells SW1 to SW4, SW11 to SW15: Switch

Claims (3)

A voltage adjustment system for adjusting a voltage value difference between a plurality of battery cells connected in series,
Two battery cells that are respectively provided corresponding to a predetermined plurality of combinations among all combinations of two battery cells extracted from the plurality of battery cells and that constitute each combination are the two batteries. A plurality of adjustment circuits connected in a parallel state in which the same polarity of the cells are energized;
A plurality of switches provided corresponding to each of the predetermined plurality of combinations, and selectively set to a normal position that blocks each of the plurality of adjustment circuits and an adjustment position that connects the adjustment circuits;
Detecting means for detecting each voltage value of the plurality of battery cells;
A first determination unit that determines that a start condition is satisfied when there are two battery cells in which a difference between the voltage values detected by the detection unit exceeds a preset first predetermined voltage value;
A second determination that the end condition is satisfied when there is no two battery cells in which a difference between the voltage values detected by the detection means exceeds a second predetermined voltage value set in advance below the first predetermined voltage value; A determination means;
When the first determination unit determines that the start condition is satisfied, one combination is determined as a processing target from the plurality of predetermined combinations, and the processing target combination among the plurality of switches is determined. Until the second determination means determines that the end condition is satisfied, the adjustment process of continuously setting only the switch to the adjustment position until the voltage values of the two battery cells constituting the combination are averaged And a control unit that changes and repeats the combination of the processing targets according to a preset order. The voltage regulation system according to claim 1,
The predetermined plurality of combinations are all combinations except for a combination of two battery cells adjacently connected in series. The voltage regulation system according to claim 1 or 2,
The second predetermined voltage value is less than the first predetermined voltage value.

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