JP2015061378A - Balance correction device and power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a damage of an element configuring a circuit when a line disconnection occurs in the circuit.SOLUTION: A balance correction device 1 includes capacitive elements C1, C2, connected between the positive and negative terminals of power storage cells B1, B2, for equalizing the voltages of the power storage cells B1, B2 through an inductor L by the on/off control of switching elements S1, S2. The balance correction device 1 further includes constant voltage diodes D1, D2 connected in an inverse direction between the positive and negative terminals of the power storage cells B1, B2, and having a breakdown voltage higher than the maximum value that the battery voltage of the power storage cells connected in the inverse direction can take, and lower than the withstanding voltage of an element, constituting the balance correction device 1, which may be damaged by a high voltage applied due to the disconnection of a line that connects the power storage cells to the capacitive elements C1, C2.

Description

  The present invention relates to a balance correction device and a power storage device for equalizing voltages between power storage cells or between power storage modules composed of a plurality of power storage cells connected in series in an assembled battery composed of a plurality of power storage cells connected in series.

  In an assembled battery in which a plurality of power storage cells are connected in series, it is necessary to suppress variations in voltage (electromotive force) between the power storage cells in order to prevent a reduction in discharge capacity and a reduction in life. In particular, as in a power storage device used in an electric vehicle or the like, an assembled battery composed of a large number of power storage cells is required to strictly suppress voltage variation between the power storage cells.

  As a mechanism for equalizing the voltage between the storage cells, for example, in Patent Document 1, one end of the inductor L is connected to the connection point of the secondary batteries B1 and B2 connected in series, and the other end of the inductor L is connected. A first mode in which current flows through a first closed circuit formed by connecting to the other end of the battery B1, and a second closed circuit formed by connecting the other end of the inductor L to the other end of the battery B2. Disclosed is a so-called converter-type balance correction method for equalizing the voltages of the battery B1 and the battery B2 by executing an operation (switching operation) that alternately repeats the second mode to be flowd alternately for a short period of time. Yes.

  Further, in Patent Document 2, in the converter type balance correction circuit, if the connection between the power source and the balance correction device is cut during operation, the drive circuit of the switching element may be damaged by the counter electromotive force of the inductor. In view of the above, it is disclosed to provide a voltage stabilization circuit that maintains a voltage difference between the first reference voltage input terminal and the second reference voltage input terminal within a predetermined range.

JP 2001-185229 A JP 2012-217243 A

  FIG. 9 shows an example of a converter type balance correction circuit 7. As shown in the figure, the battery cells B1 and B2 are connected in series to constitute the battery assembly 3. The positive and negative terminals 31 and 32 of the assembled battery 3 include, for example, a current supply source that supplies a charging current to the assembled battery 3 (for example, a charger, a regenerative circuit, etc.) and a load that uses the power of the assembled battery 3 (for example, Motor, electronic circuit, various electric products, etc.) are connected.

  One end of the inductor L is connected to a line connecting the negative electrode of the storage cell B1 and the positive electrode of the storage cell B2. A switching element S1 is provided on the line connecting the other end of the inductor L and the positive electrode of the storage cell B1. A switching element S2 is provided on a line connecting the other end of the inductor L and the negative electrode of the storage cell B2.

  The switching elements S1 and S2 are configured using, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). Switching elements S1 and S2 are complementary to each other so that when one switching element is turned on, the other switching element is turned off by gate drivers G1 and G2 controlled by control signals φ1 and φ2 generated by control circuit 10. Works.

  As shown in the figure, a capacitive element C1 is provided between one end of the inductor L and the positive electrode of the storage cell B1, and a capacitive element C2 is provided between one end of the inductor L and the negative electrode of the storage cell B2. It has been. Capacitance elements C1 and C2 are provided for the purpose of, for example, reducing noise generated due to the on / off operation of the switching elements, mitigating voltage changes occurring in power storage cells B1 and B2 due to switching, and the like.

  The control circuit 10 outputs a control signal to control the gate drivers G1 and G2, thereby alternately turning on and off the switching element S1 and the switching element S2 with a predetermined duty ratio. As a result, energy is transferred between the storage cell B1 and the storage cell B2, and as a result, the voltages of the storage cell B1 and the storage cell B2 are equalized.

  In the balance correction circuit 7 having the above configuration, for example, as shown in FIG. 10, when a disconnection 71 occurs in a line connecting the connection point J1 of the storage cells B1 and B2 and the terminals of the capacitor C1 or the capacitor C2, There is a possibility that elements (control circuit 10, gate drivers G1 and G2, switching elements S1 and S2, capacitors C1 and C2, etc.) constituting the balance correction circuit 7 may be damaged.

  That is, when the disconnection 71 occurs, the capacitor C1 and the capacitor C2 are respectively applied with the voltage equivalent to the voltage division between the positive and negative terminals of the series storage cell constituted by connecting the storage cells B1 and B2 in series. Deviations occur in the voltages generated in the capacitors C1 and C2 due to variations in capacitance (impedance) of C1 and C2, the influence of dark current flowing through the balance correction circuit 7, and the like, thereby constituting the balance correction circuit 7 A voltage exceeding the withstand voltage may be applied to the device, resulting in damage to the element.

  The present invention has been made to solve such a problem, and is capable of preventing damage to elements constituting a circuit when the circuit is disconnected. The object is to provide a device.

  In order to achieve the above object, one of the present inventions is an assembled battery composed of a plurality of power storage cells connected in series, and between power storage cells or between power storage modules composed of a plurality of power storage cells connected in series. A balance correction device for equalizing voltage, the inductor having one end connected to a connection point between the first power storage module and the second power storage module that are connected back and forth, and the first power storage A first switching element connected in series with the inductor between the positive and negative terminals of the module; a second switching element connected in series with the inductor between the positive and negative terminals of the second power storage module; and the first On / off control of the switching element and the second switching element controls the supply of current to each of the power storage modules. Then, a plurality of switching controllers connected between the positive and negative terminals of the power storage cell, causing power transfer between the power storage modules via the inductor and equalizing the voltage between the power storage modules. Capacitance element and reversely connected between the positive and negative terminals of the power storage cell or between the positive and negative terminals of the power storage module, the battery voltage of the power storage cell or the power storage module connected in the reverse direction is higher than the maximum value that can be taken, In addition, a breakdown voltage lower than the breakdown voltage of the element constituting the balance correction device, which may be damaged when a high voltage is applied due to a disconnection in a line connecting the storage cell and the capacitive element, And a constant voltage diode.

  Another aspect of the present invention is the balance correction device described above, wherein a capacitor element connected between the positive and negative terminals of a series storage cell composed of a plurality of the storage cells connected in series, and the positive and negative terminals of the storage cell Or the reverse connection is made between the positive and negative terminals of the power storage module, and the power storage cell connected in the reverse direction or the battery voltage of the power storage module is higher than the maximum possible value, and the series storage cell and the capacitor element And a constant voltage diode having a breakdown voltage lower than the breakdown voltage of an element constituting the balance correction device that may be damaged when a high voltage is applied to the line connecting the two.

  Another aspect of the present invention is the balance correction device, wherein the element that may be damaged by applying a high voltage due to the disconnection includes the first switching element and the second switching element. It is at least one of a switching element, an element constituting the switching control unit, and the capacitive element.

  Another aspect of the present invention is a power storage device including the plurality of power storage cells and the balance correction device.

  In addition, the subject which this application discloses, and its solution method are clarified by the column of the form for inventing, and drawing.

  ADVANTAGE OF THE INVENTION According to this invention, when the disconnection arises in a circuit, it can prevent that the element which comprises the circuit will be damaged.

2 is an example of a balance correction circuit 1; (A) is a waveform of the control signals φ1 and φ2 output by the control circuit 10 in the first period, and (b) to (d) are waveforms of a current flowing through the inductor L in the first period. It is a figure explaining operation | movement of the balance correction circuit 1 when the disconnection 81 arises in the track | line. It is an example of the balance correction circuit 1 corresponding to equalization of the voltage of three electrical storage cells B1-B3. It is a figure explaining operation | movement of the balance correction circuit 1 when the disconnection 82 arises in the track | line. It is a figure explaining operation | movement of the balance correction circuit 1 when the disconnection 83 arises in the track | line. It is another example of the balance correction circuit 1 corresponding to equalization of the voltage of three electrical storage cells B1-B3. It is a figure explaining operation | movement of the balance correction circuit 1 when the disconnection 84 arises in the track | line. It is an example of the balance correction circuit 7 of a converter system. It is a figure which shows a mode that the disconnection 71 has arisen on the track.

  Hereinafter, embodiments of the present invention will be described. In the following description, the same or similar parts may be denoted by the same reference numerals and redundant description may be omitted.

  FIG. 1 shows a balance correction circuit 1 (balance correction apparatus) shown as an embodiment of the present invention. The balance correction circuit 1 includes, for example, a power storage device (an electric vehicle, a hybrid vehicle, an electric motorcycle, a railway vehicle, a lift, a power storage device for system linkage, a personal computer, a notebook computer) that uses an assembled battery composed of a plurality of power storage cells connected in series. (Book type computer, mobile phone, smartphone, PDA device, etc.). The power storage cell is, for example, a lithium ion secondary battery, a lithium ion polymer secondary battery, or the like, but may be another type of power storage element such as an electric double layer capacitor.

  When manufacturing quality and the degree of deterioration differ between the storage cells that make up the assembled battery, battery characteristics (battery capacity, discharge voltage characteristics) may vary between storage cells. As a result, the voltage between the storage cells may vary during charging and discharging. Therefore, in order to suppress the occurrence of such variation, the balance correction circuit 1 equalizes the voltage between the storage cells or the voltage between the storage modules composed of a plurality of storage cells connected in series (ensuring cell balance). To work.

  As shown in the figure, an assembled battery 3 is constituted by power storage cells B1 and B2 connected in series. The positive and negative terminals 31 and 32 of the assembled battery 3 include, for example, a current supply source (for example, a charger, a regenerative circuit, etc.) that supplies a charging current to the assembled battery 3 and a load that functions using the electromotive force of the assembled battery 3. (For example, a motor, an electronic circuit, an electrical product, etc.) are connected.

  One end of the inductor L is connected to a line connecting the negative electrode of the storage cell B1 and the positive electrode of the storage cell B2. A switching element S1 is provided on the line connecting the other end of the inductor L and the positive electrode of the storage cell B1. A switching element S2 is provided on a line connecting the other end of the inductor L and the negative electrode of the storage cell B2.

  The switching elements S1 and S2 are configured using MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). The switching elements S1 and S2 are turned off when one switching element is turned on by the gate drivers G1 and G2 controlled by the control signals φ1 and φ2 generated by the control circuit 10 (switching control unit). Operate in a complementary manner. The switching elements S1 and S2 can also be configured using bipolar transistors.

  A capacitive element C1 is provided between one end of the inductor L and the positive electrode of the storage cell B1, and a capacitive element C2 is provided between one end of the inductor L and the negative electrode of the storage cell B2. These capacitive elements C1 and C2 are provided for the purpose of, for example, reducing noise caused by the on / off operation of the switching elements, and mitigating voltage changes that occur in the storage cells B1 and B2 due to switching.

  As shown in the figure, the control circuit 10 includes a control signal generation circuit 101, a duty ratio control circuit 102, and a measurement circuit 103 (voltage measurement unit). The control circuit 10 includes, for example, a microcomputer including an arithmetic device (CPU (Central Processing Unit), MPU (Micro Processing Unit), etc.) and a storage device (RAM (Random Access Memory), ROM (Read Only Memory), etc.). Can be realized.

  The control signal generation circuit 101 generates two-phase control signals φ1 and φ2 to be supplied to the gate drivers G1 and G2, respectively. In the present embodiment, the control signals φ1 and φ2 are two-phase square waves (for example, PWM pulse (PWM: Pulse Width Modulation)) having a predetermined duty ratio (for example, 50%).

  The duty ratio control circuit 102 controls the duty ratio of the control signals φ1 and φ2 generated by the control signal generation circuit 101. In addition, the duty ratio control circuit 102 determines the speed, safety, efficiency, etc. of the voltage between the storage cells B1, B2 according to the voltage of the storage cells B1, B2 obtained from the measurement value of the measurement circuit 103, for example. From the viewpoint of improvement, the duty ratios of the control signals φ1 and φ2 are controlled so as to be appropriately equalized.

  The measurement circuit 103 acquires in real time a measurement value of a voltage (for example, a voltage between the connection points J5-J3, a voltage between the connection points J3-J10, etc.) of a predetermined part of the line constituting the balance correction circuit 1. Then, the acquired measurement value is transmitted to the control signal generation circuit 101 and the duty ratio control circuit 102.

  As shown in the figure, a constant voltage diode D1 is connected in the reverse direction between the positive and negative terminals of the storage cell B1. As the constant voltage diode D1, the breakdown voltage (zener voltage) is higher than the maximum value that can be taken by the battery voltage of the storage cell B1, and disconnection occurs in the line connecting the connection point J1 and the connection point J3. Select a device that has a lower withstand voltage than the elements (for example, the control circuit 10, the gate driver G1, the switching element S1, and the capacitor C1) constituting the balance correction circuit 1 that may be damaged when a high voltage is applied. doing. Since the constant voltage diode D1 is selected such that its breakdown voltage is higher than the maximum value that the battery voltage of the storage cell B1 can take, as long as the balance correction circuit 1 operates normally, the constant voltage diode D1 is constant. The voltage diode D1 is not energized.

  As shown in the figure, a constant voltage diode D2 is connected in the reverse direction between the positive and negative terminals of the storage cell B2. As the constant voltage diode D2, the breakdown voltage is higher than the maximum value that the battery voltage of the storage cell B2 can take, and a high voltage is generated by disconnection in the line connecting the connection point J1 and the connection point J3. An element that is lower than the withstand voltage of the elements (for example, the control circuit 10, the gate driver G2, the switching element S2, and the capacitor C2) constituting the balance correction circuit 1 that may be damaged when applied is selected. In this manner, since the constant voltage diode D2 is selected such that its breakdown voltage is higher than the maximum value that the battery voltage of the storage cell B2 can take, as long as the balance correction circuit 1 operates normally, the constant voltage diode D2 is constant. The voltage diode D2 is not energized.

  Next, the basic operation of the balance correction circuit 1 having the above configuration will be described with reference to FIG.

  FIG. 2A shows the waveforms of the control signals φ1 and φ2 generated by the control circuit 10 during the period when the on / off control of the switching elements S1 and S2 is performed. During the period, the control circuit 10 generates control signals φ1 and φ2 composed of square waves that are complementarily turned on and off in the same cycle as shown in FIG.

  2B to 2D are waveforms of the current iL flowing through the inductor L during the period when the on / off control of the switching elements S1 and S2 is performed. Of these, FIG. 2B shows a waveform of the current iL flowing through the inductor L when the voltage E1 of the storage cell B1 is larger than the voltage E2 of the storage cell B2, and FIG. 2C shows the voltage of the storage cell B1. FIG. 2D shows the waveform of the current iL flowing through the inductor L when E1 is smaller than the voltage E2 of the storage cell B2, and FIG. 2D shows that the voltage E1 of the storage cell B1 and the voltage E2 of the storage cell B2 are equal ( This is a waveform of the current iL flowing through the inductor L in the case of substantially equal).

  As shown in FIG. 2B, when the voltage E1 of the energy storage cell B1 is larger than the voltage E2 of the energy storage cell B2 (E1> E2), during the period when the switching element S1 is on and the switching element S2 is off, The positive electrode of the storage cell B1 → the connection point J7 → the connection point J6 → the connection point J5 → the switching element S1 → the connection point J4 → the inductor L → the connection point J3 → the connection point J2 → the connection point J1 → the negative electrode path of the storage cell B1 ( Hereinafter, this is referred to as a first path), and a current iL flows. That is, during this period, current iL flows mainly in the direction of the solid line arrow shown in FIG.

  Thereafter, when the switching element S1 is turned off and the switching element S2 is turned on, the energy stored in the inductor L is changed from the inductor L → the connection point J3 → the connection point J2 → the connection point J1 → the positive electrode of the storage cell B2 → the storage cell B2. Of the negative electrode → the connection point J8 → the connection point J9 → the connection point J10 → the switching element S2 → the inductor L, whereby the storage cell B2 is charged. Then, when the energy of the inductor L is lost, the current iL starts to flow through the inductor L in the reverse direction (the direction of the broken line arrow shown in FIG. 1).

  As shown in FIG. 2C, when the voltage E1 of the energy storage cell B1 is smaller than the voltage E2 of the energy storage cell B2 (E1 <E2), during the period in which the switching element S1 is off and the switching element S2 is on, The positive electrode of the storage cell B2 → the connection point J1 → the connection point J2 → the connection point J3 → the inductor L → the connection point J4 → the switching element S2 → the connection point J10 → the connection point J9 → the connection point J8 → the negative electrode path of the storage cell B2 ( Hereinafter, this is referred to as a second path), and current iL flows. That is, during this period, current iL flows mainly in the direction of the broken line arrow shown in FIG.

  Thereafter, when the switching element S2 is turned off and the switching element S1 is turned on, the energy stored in the inductor L is changed from the inductor L → the connection point J4 → the switching element S1 → the connection point J5 → the connection point J6 → the connection point J7 → power storage. The battery B1 is discharged along the path of the positive electrode → the negative electrode of the storage cell B1 → the connection point J1 → the connection point J2 → the connection point J3 → the inductor L, whereby the storage cell B1 is charged. When the energy of the inductor L is lost, the current iL begins to flow in the inductor L in the reverse direction (the direction of the solid line arrow shown in FIG. 1).

  As described above, when there is a voltage difference between the storage cells B1 and B2, the current iL alternately flows through the first path and the second path, thereby transferring energy between the storage cell B1 and the storage cell B2. As a result, both voltages are equalized to ensure cell balance. As shown in FIG. 2D, when the voltage E1 of the storage cell B1 and the voltage E2 of the storage cell B2 are equal (E1 = E2), the storage cell accompanies the on / off control of the switching elements S1 and S2. The balance of energy exchanged between B1 and B2 is balanced, and the voltage between the storage cells B1 and B2 is kept uniform.

  The control circuit 10 measures the voltage (the voltage between the respective terminals of the storage cells B1 and B2 (for example, the voltage between the connection points J5-J3, the voltage between the connection points J3-J10, etc.) measured by the measurement circuit 103. When monitoring in real time and detecting that the voltages of the storage cells B1 and B2 are equal (substantially match), the on / off control of the switching elements S1 and S2 is stopped.

  In addition, the control circuit 10 is acquired from the measured value of the measurement circuit 103, for example so that the voltage between electrical storage cell B1, B2 may be equalized appropriately from a viewpoint of improving quickness, safety, efficiency, etc. The duty ratios of the control signals φ1 and φ2 may be controlled according to the voltages of the storage cells B1 and B2.

<Operation at disconnection>
Next, the operation of the balance correction circuit 1 when a disconnection occurs in the line connecting the connection point J1 and the connection point J3 of the balance correction circuit 1 shown in FIG.

  As shown in FIG. 3, when a disconnection 81 occurs on the line connecting the connection point J1 and the connection point J3, between the positive and negative terminals of the capacitors C1 and C2 connected in series (between the connection point J5 and the connection point J9). Is applied with a voltage between the positive and negative terminals of the series storage cell constituted by connecting the storage cells B1 and B2 in series, and the voltage between the positive and negative terminals of the capacitor C1 is equivalent to the divided voltage, that is, the capacitors C1 and C2. An attempt is made to change the partial pressure to be determined by the variation in capacitance (impedance) and the dark current of the balance correction circuit 1. However, when the voltage between the positive and negative terminals of the capacitor C1 rises, the constant voltage diode D1 is energized when the voltage exceeds the breakdown voltage of the constant voltage diode D1, and the rise of the voltage between the positive and negative terminals of the capacitor C1 stops. Similarly, when the voltage between the positive and negative terminals of the capacitor C2 increases, the constant voltage diode D2 is energized when the voltage exceeds the breakdown voltage of the constant voltage diode D2, and the voltage between the positive and negative terminals of the capacitor C2 increases. Stops.

  As described above, in the balance correction circuit 1 according to the present embodiment, even when the disconnection 81 occurs in the line connecting the connection point J1 and the connection point J3 of the balance correction circuit 1, the positive and negative of the capacitors C1 and C2 respectively. The voltage between the terminals does not increase beyond the withstand voltage of the elements constituting the balance correction circuit 1 (for example, the control circuit 10, the gate drivers G1 and G2, the switching elements S1 and S2, and the capacitors C1 and C2), It is possible to reliably prevent the elements constituting the balance correction circuit 1 from being damaged due to the disconnection 81.

<When there are three or more storage cells>
The configuration of the balance correction circuit 1 described above can be expanded when there are three or more power storage cells.

  FIG. 4 is an example of the balance correction circuit 1 corresponding to equalization of the voltages of the three power storage cells B1 to B3, which is shown as an example when there are three or more power storage cells. In the figure, the control circuit 10 complementarily turns on and off the switching elements S1 and S2 to equalize the voltage of the storage cell B1 and the voltage of the storage cell B2, and turns on and off the switching elements S3 and S4 in a complementary manner. The voltage of the storage cell B2 and the voltage of the storage cell B3 are equalized. By these controls, the voltage of the power storage cell B2 is equalized with the voltages of the two power storage cells B1, B3, and as a result, the voltages of the three power storage cells B1, B2, B3 are equalized.

  In the figure, the capacitive elements C1 to C4 are all provided for the purpose of reducing noise caused by the on / off operation of the switching elements S1 to S4 and alleviating voltage changes occurring in the storage cells B1 to B3. Yes. As shown in the figure, the capacitor C1 is connected between the positive and negative terminals of the storage cell B1, the capacitors C2 and C3 are both connected between the positive and negative terminals of the storage cell B2, and the capacitor C4 is connected between the positive and negative terminals of the storage cell B3. ing.

  As shown in the figure, each of the constant voltage diodes D1, D2, and D3 is connected in the reverse direction between the positive and negative terminals of the storage cells B1, B2, and B3. The constant voltage diodes D1, D2, and D3 each have a breakdown voltage that is higher than the maximum value that can be taken by the battery voltages of the storage cells B1, B2, and B3, and constitutes the balance correction circuit 1. An element (for example, control circuit 10, gate drivers G1, G2, G3, G4, switching elements S1, S2, S3, capacitors C1, C2, C3) having a lower withstand voltage is selected. Since the constant voltage diodes D1, D2, and D3 are selected in such a manner that their respective breakdown voltages are higher than the maximum values that can be taken by the battery voltages of the storage cells B1, B2, and B3, the balance correction is performed. As long as the circuit 1 operates normally, the constant voltage diodes D1, D2, and D3 are not energized.

  Next, as shown in FIG. 5, for example, when a disconnection 82 occurs in the line connecting the connection point J41 and the connection point J43, the negative terminals of the capacitors C2 and C3 connected in parallel (connection point J55, connection point J66). And a voltage between the positive and negative terminals of the series storage cell configured by connecting the storage cells B1 and B2 in series, between the positive terminal of the C1 connected in series (the connection point J46). As a result, the voltage between the positive and negative terminals of the capacitors C2 and C3 connected in parallel (between the connection point J44 (connection point J67) and the connection point J55 (connection point J66)) may increase. However, when the voltage between the positive and negative terminals of the capacitors C2 and C3 connected in parallel rises and the voltage exceeds the breakdown voltage of the constant voltage diode D2, the constant voltage diode D2 is energized, and the capacitors C2 and C3 connected in parallel The rise in voltage between the positive and negative terminals of is stopped. Similarly, when the voltage between the positive and negative terminals of the capacitor C1 (between the connection point J46 and the connection point J44) rises, the voltage between the positive and negative terminals of the capacitor C1 rises and the voltage of the constant voltage diode D1 increases. When the breakdown voltage is exceeded, the constant voltage diode D1 is energized, and the voltage increase between the positive and negative terminals of the capacitor C1 stops.

  As described above, in the balance correction circuit 1 of the present embodiment, even when the disconnection 82 occurs in the line connecting the connection point J41 and the connection point J43, the voltage between the positive and negative terminals of the capacitors C1, C2, and C3. Can be prevented from exceeding the withstand voltage of the elements constituting the balance correction circuit 1, and the elements constituting the balance correction circuit 1 can be reliably prevented from being damaged.

  Next, for example, as shown in FIG. 6, when a disconnection 83 occurs in the line connecting the connection point J51 and the connection point J53, the positive terminals of the capacitors C2 and C3 connected in parallel (connection point J44, connection point J67). And a voltage between the positive and negative terminals of a series storage cell constituted by connecting the storage cells B2 and B3 in series, between the negative terminal of the C4 connected in series (connection point J64), As a result, the voltage between the positive and negative terminals of the capacitors C2 and C3 (between the connection point J44 (connection point J67) and the connection point J55 (connection point J66)) may increase. However, when the voltage between the positive and negative terminals of the capacitors C2 and C3 connected in parallel rises and the voltage exceeds the breakdown voltage of the constant voltage diode D2, the constant voltage diode D2 is energized, and the capacitors C2 and C3 connected in parallel The rise in voltage between the positive and negative terminals of is stopped. Similarly, when the voltage between the positive and negative terminals of the capacitor C4 (between the connection point J66 and the connection point J64) rises, the voltage between the positive and negative terminals of the capacitor C4 rises, and the voltage of the constant voltage diode D3 increases. When the breakdown voltage is exceeded, the constant voltage diode D4 is energized, and the voltage increase between the positive and negative terminals of the capacitor C4 stops.

  As described above, in the balance correction circuit 1 of the present embodiment, even when the disconnection 83 occurs in the line connecting the connection point J51 and the connection point J53, the voltage between the positive and negative terminals of the capacitors C2, C3, and C4. Can be prevented from exceeding the withstand voltage of the elements constituting the balance correction circuit 1, and the elements constituting the balance correction circuit 1 can be reliably prevented from being damaged.

  FIG. 7 shows the equalization of the voltages of the three storage cells B1 to B3 as an example in the case where there are three or more storage cells and the connection state of the capacitors is different from that of the balance correction circuit 1 shown in FIG. Is an example of a balance correction circuit 1 corresponding to the above. As shown in the figure, the capacitor C1 is connected between the positive and negative terminals of the storage cell B2, the capacitor C2 is connected between the positive and negative terminals of a series storage cell formed by connecting the storage cells B1 and B2, and the capacitor C3 is connected to the storage cell B3. The capacitor C4 is connected between the positive and negative terminals of a series power storage cell constituted by connecting power storage cells B2 and B3 in series.

  In the figure, the control circuit 10 complementarily turns on and off the switching elements S1 and S2 to equalize the voltage of the storage cell B1 and the voltage of the storage cell B2, and turns on and off the switching elements S3 and S4 in a complementary manner. The voltage of the storage cell B2 and the voltage of the storage cell B3 are equalized. By these controls, the voltage of the power storage cell B2 is equalized with the voltages of the two power storage cells B1, B3, and as a result, the voltages of the three power storage cells B1, B2, B3 are equalized.

  The capacitive elements C1 to C4 are all provided for the purpose of reducing noise caused by the on / off operation of the switching elements S1 to S4, mitigating voltage changes occurring in the storage cells B1 to B3, and the like.

  As shown in the figure, each of the constant voltage diodes D1, D2, D3 is connected in the reverse direction between the positive and negative terminals of the storage cells B1, B2, B3. Each of the constant voltage diodes D1, D2, D3 has a breakdown voltage higher than the maximum value that each battery voltage of the storage cells B1, B2, B3 can take, and constitutes the balance correction circuit 1. Lower than the breakdown voltage of the elements (for example, the control circuit 10, gate drivers G1, G2, G3, G4, switching elements S1, S2, S3, capacitors C1, C2, C3), and the sum of the breakdown voltages of D1, D2 and The sum of the breakdown voltages of D2 and D3 is selected to be lower than the breakdown voltage of each of the capacitors C2 and C4. Since the constant voltage diodes D1, D2 and D3 are selected in such a way that the breakdown voltage is higher than the maximum value that can be taken by the battery voltages of the storage cells B1, B2 and B3, the balance correction circuit 1 is normal. The constant voltage diodes D1, D2, and D3 are not energized as long as they are operating.

  Next, the operation at the time of disconnection will be described. For example, as shown in FIG. 8, when the disconnection 84 occurs in the line connecting the connection point J51 and the connection point J53, between the positive and negative terminals of the capacitors C1 and C3 connected in series (the connection between the connection point J44 and the connection point J64). Between the positive and negative terminals of the series storage cell constituted by connecting the storage cells B2 and B3 in series, which may increase the voltage between the positive and negative terminals of the capacitor C1. However, when the voltage between the positive and negative terminals of the capacitor C1 rises and the voltage exceeds the breakdown voltage of the constant voltage diode D2, the constant voltage diode D2 is energized, and the voltage increase between the positive and negative terminals of the capacitor C1 stops. Similarly, when the voltage between the positive and negative terminals of the capacitor C3 rises, similarly, when the voltage between the positive and negative terminals rises and the voltage exceeds the breakdown voltage of the constant voltage diode D3, the constant voltage diode D3 is energized, and the capacitor C3 The voltage rise between the positive and negative terminals stops. Further, between the positive and negative terminals of the series storage cell constituted by connecting the storage cells B1, B2, and B3 in series between the positive and negative terminals of the capacitors C2 and C3 connected in series (between the connection point J46 and the connection point J64). This may cause the voltage between the positive and negative terminals of the capacitor C2 to rise. However, when the voltage between the positive and negative terminals of the capacitor C2 rises and the voltage exceeds the sum of the breakdown voltages of the constant voltage diodes D1 and D2, the constant voltage diodes D1 and D2 are energized, and the voltage between the positive and negative terminals of the capacitor C2 The ascent stops. Similarly, when the voltage between the positive and negative terminals of the capacitor C3 rises, the voltage between the positive and negative terminals rises and the constant voltage diode D3 is energized when the voltage exceeds the breakdown voltage of the constant voltage diode D3. The rise in voltage between the positive and negative terminals of the capacitor C3 stops.

  As described above, in the balance correction circuit 1 of the present embodiment, even when the disconnection 84 occurs in the line connecting the connection point J51 and the connection point J55 of the balance correction circuit 1, each of the capacitors C1, C2, and C3. The voltage between the positive and negative terminals does not increase beyond the withstand voltage of the elements constituting the balance correction circuit 1, and the elements constituting the balance correction circuit 1 can be reliably prevented from being damaged. .

  By the way, description of embodiment described above is for making an understanding of this invention easy, and does not limit this invention. It goes without saying that the present invention can be changed and improved without departing from the gist thereof, and that the present invention includes equivalents thereof.

  For example, the balance correction circuit of the present invention may be provided separately from the storage cell, or may be integrated with the storage cell to form a battery pack or the like.

  DESCRIPTION OF SYMBOLS 1 Balance correction circuit, 10 Control circuit, 101 Control signal generation circuit, 102 Duty ratio control circuit, 103 Measuring circuit, L Inductor, C1, C2, C3, C4 Capacitance element, B1, B2, B3 Storage cell, S1, S2, S3, S4 switching element, D1, D2, D3 constant voltage diode

Claims (4)

In an assembled battery composed of a plurality of power storage cells connected in series, a balance correction device for equalizing a voltage between the power storage cells or between power storage modules composed of a plurality of power storage cells connected in series,
An inductor having one end connected to a connection point between the first power storage module and the second power storage module connected back and forth;
A first switching element connected in series with the inductor between the positive and negative terminals of the first power storage module;
A second switching element connected in series with the inductor between the positive and negative terminals of the second power storage module;
On / off control of the first switching element and the second switching element controls the supply of current to each of the power storage modules, thereby causing power to be transferred between the power storage modules via the inductor. Switching controller for equalizing the voltage between the storage modules,
A plurality of capacitive elements connected between the positive and negative terminals of the storage cell;
Reversely connected between the positive and negative terminals of the power storage cell or between the positive and negative terminals of the power storage module, the battery voltage of the power storage cell or the power storage module connected in the reverse direction is higher than the maximum value that can be taken, and the power storage A constant voltage diode having a breakdown voltage lower than the breakdown voltage of an element constituting the balance correction device, which may be damaged when a high voltage is applied to the line connecting the cell and the capacitive element. And a balance correction device. The balance correction apparatus according to claim 1,
A capacitive element connected between the positive and negative terminals of a series storage cell consisting of a plurality of the storage cells connected in series;
Reversely connected between the positive and negative terminals of the power storage cell or between the positive and negative terminals of the power storage module, the battery voltage of the power storage cell or the power storage module connected in the reverse direction is higher than the maximum value that can be taken, and the series A constant voltage having a breakdown voltage lower than the withstand voltage of the element constituting the balance correction device, which may be damaged when a high voltage is applied to the line connecting the storage cell and the capacitive element. A balance correction device comprising a diode. The balance correction apparatus according to claim 1 or 2,
The element that may be damaged when a high voltage is applied due to the disconnection includes the first switching element, the second switching element, the element constituting the switching control unit, and the capacitor element. A balance correction device that is at least one of them.   A power storage device comprising: the plurality of power storage cells; and the balance correction device according to any one of claims 1 to 3.

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