JP2009165206A - Charge and discharge apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charge and discharge apparatus which reduces energy consumption required for leveling battery voltage through selective charge and discharge, with a compact circuit easily integrated. <P>SOLUTION: When a cell selecting circuit CS selects a cell 2 of maximum charge amount among cells in battery modules 3, a cell discharge circuit CD discharges the cell 2 of the maximum charge amount selected by the cell selecting circuit CS. Furthermore, when a module voltage detecting circuit MV detects module voltages for each battery module 3 in a battery pack 4, a system control circuit SE causes a module charging circuit MC to charge battery modules 3 where voltage differences drop below the reference voltage among the battery modules 3, based on the detection results of the module voltage. A cell charging circuit CC may charge a cell 2 of minimum charge amount selected by the cell selecting circuit CS and a module discharge circuit MD may discharge battery modules 3 where voltage differences exceed the reference value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a charge / discharge device for leveling (homogenizing) the state of charge of a large number of cells constituting an assembled battery.

  In order to level the state of charge of the cells constituting the assembled battery, it may be possible to detect and level the voltage of each cell. However, since the voltage detection circuit for detecting the cell voltage is complex and expensive, the voltage of the battery module (module voltage) in which a plurality of cells are connected in series (module voltage) is detected, and the number of objects to be detected is reduced. By reducing the number of detection circuits, the state of charge of the cells is leveled. In that case, only the discharge operation of the cells is performed by the leveling means to level the charge states of a plurality of cells (see, for example, Patent Document 1).

In addition, when an assembled battery is continuously used for a long time in an electric vehicle (EV), a hybrid electric vehicle (HEV), a fuel cell electric vehicle (FCEV), etc., a specific cell If there is no abnormality in the battery and there is no significant bias in the battery characteristics or temperature environment of each cell, the variation in the charge state of each cell generally follows a normal distribution. When leveling the voltage of cells that vary according to such a normal distribution, when trying to minimize the amount of energy consumed for the leveling operation of charge and discharge, selectively discharge the cells with a large amount of charge. However, an operation of selectively charging a cell with a small amount of charge is performed. That is, the cell voltage is leveled by appropriately performing a discharging operation and a charging operation for each cell by the leveling means (see, for example, Patent Document 2).
In addition, a technology has been proposed in which a charging circuit is provided with a bypass circuit, and for a cell with a large amount of charge, a charging current is shunted to the bypass circuit to equalize the state of charge of the cell (see, for example, Patent Document 3). .

JP 2002-325370 A (paragraphs [0044] to [0048], FIGS. 1 to 3) JP 2003-309931 A (paragraphs [0017] to [0021], FIGS. 1 to 3) Japanese Patent No. 3503453 (paragraphs [0011] to [0012], FIG. 1)

  However, in the case where the cell voltage is leveled only by the discharging operation by the leveling means (described in Patent Document 1), in order to converge the charged amount varying in each cell within a certain range, the cell with the minimum charged amount is used. As a reference, a voltage threshold is set, and only the cells exceeding the voltage threshold are discharged. In this discharge operation, a resistor is connected in parallel to each cell and energized to consume energy charged in the cell as Joule heat. Thus, when the leveling of the cell voltage by the discharge operation is repeated, the variation of the cell voltage that originally followed the normal distribution shifts to the higher voltage side (upper side) within the convergence range. Furthermore, when the cell voltage variation progresses and the cell voltage decreases beyond the convergence range of the minimum charge amount cell voltage variation, a large number of cells having a large charge amount must be discharged. Therefore, in order to dissipate the Joule heat generated by the discharge operation of a large number of cells, a cooling mechanism is required in the discharge circuit, and the leveling mechanism becomes large and the manufacturing cost increases. In addition, there is a problem in that the proportion of energy stored in the battery is consumed as Joule heat for leveling the cell voltage.

  Further, in the case where the cell voltage is leveled by using both discharge and charge by the leveling means (described in Patent Document 2), a large number of windings corresponding to the number of cells when a DC-DC converter or the like is used in the charging circuit. Therefore, there is a problem that it is difficult to integrate and downsize the charging circuit.

  Furthermore, for example, in HEV vehicles, a high voltage assembled battery of about 150 to 300 [V] is configured by connecting a large number of cells in series. For this reason, the circuit for operating the vehicle control system and the assembled battery is provided with an independent power supply by insulating the power supply system (described in Patent Document 3). That is, the power source of the battery pack operation circuit uses a high voltage battery pack itself, and the power source of the control system uses a low voltage power source insulated from the high voltage power source. Therefore, when the vehicle is left unattended, the power of the control system is cut off, but the power of the battery pack operating circuit remains connected, so the power stored in the battery pack leaks. As a result, there is a problem that the capacity of the assembled battery may be consumed.

  The present invention has been made in view of such circumstances, and it is easy to reduce the size and integration of the circuit, and the energy consumption required for leveling the battery voltage by selectively performing charging and discharging. It aims at providing the charging / discharging apparatus which can be reduced.

  In order to solve the above-mentioned problem, the invention according to claim 1 is connected to an assembled battery formed by connecting a plurality of battery modules each including a plurality of cells in series, and the cell is selected according to the state of charge of the cell or the battery module. Or a charging / discharging device for charging / discharging the battery module, a cell selection circuit for selecting a cell with the maximum charge amount between each cell in the battery module, and a maximum selected by the cell selection circuit provided for each cell A cell discharge circuit that discharges cells of a charge amount, a module voltage detection circuit that detects a module voltage for each battery module in the assembled battery, and a battery module that is provided for each battery module and charges the corresponding battery module Based on the module charging circuit and the module voltage detection result by the module voltage detection circuit, the voltage difference between the battery modules is below the reference value. To the battery module, characterized by comprising a system control circuit to execute charging by the module charging circuit.

  According to this configuration, the cell discharge circuit and the module charging circuit are provided, the cell discharge circuit discharges a cell having the maximum charge amount (that is, the maximum voltage), and the module charge circuit detects the voltage between the battery modules. The battery module in which the difference is less than a predetermined reference value is charged to realize leveling (uniformization) of the voltage of each cell in the assembled battery composed of a plurality of cells. Therefore, since the battery voltage in the assembled battery can be leveled without providing a cell discharge circuit and a cell charging circuit for each cell, integration and miniaturization of each circuit of the charge / discharge device can be easily realized. It becomes possible. In other words, by using in combination the charging means for selectively charging a part of the assembled battery and the discharging means for selectively discharging a part of the assembled battery using elements that can be easily integrated and miniaturized in each circuit of the charging / discharging device. Reduce energy consumption required for voltage leveling, and at the same time, supply power from the vehicle control system to operate the battery pack so that it does not consume battery power while the vehicle is left Can do.

  The invention according to claim 2 is a charging / discharging device that is connected to an assembled battery formed by connecting a plurality of battery modules composed of a plurality of cells in series, and performs charging / discharging according to the state of charge of the cells or battery modules. A cell selection circuit that selects a cell with the minimum charge amount between cells in the battery module, a cell charge circuit that is provided for each cell and charges a cell with the minimum charge amount selected by the cell selection circuit, Module voltage detection circuit that detects module voltage for each battery module in the battery, module discharge circuit that is provided for each battery module and discharges the corresponding battery module, and module voltage detection by the module voltage detection circuit Based on the results, the module discharge circuit discharges the battery module whose voltage difference between the battery modules exceeds the reference value. Characterized by comprising a system control circuit for the row.

  According to this configuration, the cell charging circuit and the module discharging circuit are provided, the cell charging circuit charges a cell having the minimum charge amount (that is, the minimum voltage), and the module discharging circuit detects the voltage between the battery modules. The battery module in which the difference exceeds a predetermined reference value is discharged, and the battery voltage of each cell in the assembled battery composed of a plurality of cells is leveled (uniformized). Therefore, since the battery voltage in the assembled battery can be leveled without providing a cell discharge circuit and a cell charging circuit for each cell, integration and miniaturization of each circuit of the charge / discharge device can be easily realized. It becomes possible.

  Further, the invention according to claim 3 is the invention according to claim 1, wherein the system control circuit is configured to detect a module voltage detected by the module voltage detection circuit and the voltage difference between the battery modules exceeds a reference value. The discharge is performed using all the cell discharge circuits.

  According to this configuration, even if a module discharge circuit is not provided, all cell discharge circuits in the battery module are used for all battery modules in which the voltage difference between the battery modules exceeds the reference value. Therefore, integration and miniaturization of each circuit of the charging / discharging device can be realized more easily.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the cell charging circuit includes a two-phase pulse generation circuit that complementarily outputs two types of pulses having different time axes. A diode bridge that rectifies each of the two types of pulses, a capacitor that charges and outputs the power of the two types of pulses generated by the two-phase pulse generation circuit via the diode bridge, and suppresses inrush current to the capacitor And a semiconductor switching element that is provided between the cell and the capacitor and supplies / cuts off the charging energy stored in the capacitor by ON / OFF control. Instead of charging individual cells individually with the capacitor of the cell charging circuit, it is also possible to charge all the cells in the battery module with the capacitor.

  According to this configuration, the capacitor is charged by two types of pulses generated by a known two-phase pulse generation circuit, and the cell is charged by the charge of the capacitor. Therefore, since the cell charging circuit becomes extremely simple, integration and miniaturization of the cell charging circuit can be realized more easily. If all the cells in the battery module are charged together with a capacitor, module charging can be realized.

  According to the invention according to claim 5, in the invention according to claim 4, the semiconductor switching element is configured to charge the cell by ON / OFF control based on the cell charge enable / disable signal and the minimum voltage cell discrimination signal. It is characterized by performing / not implementing.

  According to this configuration, for example, if the cell charge enable / disable signal is High (Hi level) and the minimum voltage cell determination signal is only Low (Lo level) for the minimum voltage cell and the other cells are Hi, By performing ON / OFF control of the semiconductor switching element by the logic circuit, the charge of the capacitor can be supplied to only the cell having the minimum voltage for charging.

  Moreover, according to the invention which concerns on Claim 6, it is connected to the assembled battery formed by connecting the battery module which consists of several cells in series, and it performs charging / discharging according to the charge condition of a cell or a battery module A cell voltage detection circuit that performs voltage detection for each cell in the battery module, a cell discharge circuit that is provided for each cell and discharges the corresponding cell, and a battery module that is provided for each battery module. Based on the detection result of each cell voltage and module voltage by the cell voltage detection circuit, the module charging circuit is used to charge the battery module whose voltage difference between the battery modules is below the reference value using the module charging circuit To discharge cells using a cell discharge circuit for cells in which the voltage difference between cells in the battery module exceeds a reference value Characterized by comprising a control circuit.

  According to this configuration, by providing a cell voltage detection circuit that detects the voltage of each cell, the cell voltage detection circuit detects the cell voltage of each cell without providing a module voltage detection circuit or a cell selection circuit. To estimate the module voltage for each battery module. Thus, based on the detection result of each cell voltage and module voltage, the module charging circuit charges the battery module in which the voltage difference between the battery modules is lower than the reference value, and the cell discharging circuit is in the battery module. By discharging the cells in which the voltage difference between the cells exceeds the reference value, the battery voltage in the assembled battery can be leveled.

  According to the invention according to claim 7, in the invention according to claim 6, the module charging circuit includes a two-phase pulse generation circuit that complementarily outputs two types of pulses having different time axes, and each module charging circuit. A diode bridge that rectifies each of the two types of pulses, and a capacitor that is provided for each module charging circuit and that charges and outputs the power of the two types of pulses generated by the pulse generation circuit via the diode bridge. Provided for each module charging circuit, current limiting element that suppresses inrush current to the capacitor and between the battery module and the capacitor, and supplies the charging energy stored in the capacitor by ON / OFF control to the battery module / Semiconductor switching element to cut off.

  According to this configuration, the capacitor is charged with two types of pulses generated by a known two-phase pulse generation circuit, and the battery module is charged with the charge of the capacitor. Therefore, since the module charging circuit becomes extremely simple, integration and miniaturization of the module charging circuit can be realized more easily.

  According to the invention of claim 8, in the invention of claim 7, the semiconductor switching element charges the battery module by ON / OFF control based on the cell charge enable / disable signal and the minimum voltage cell discrimination signal. It is characterized by performing / non-implementing.

  According to this configuration, by performing ON / OFF control of the semiconductor switching element by the logic circuit, the charge of the capacitor can be supplied only to the battery module having the minimum voltage to be charged.

  According to the first aspect of the present invention, the cell discharge circuit discharges the cell with the maximum charge amount, and the module charging circuit charges the battery module in which the voltage difference between the battery modules is lower than the reference value. Since the battery voltage in the assembled battery can be leveled, the charging / discharging device can be integrated and made compact. Furthermore, by selectively performing charging and discharging by the module charging circuit and the cell discharging circuit, it is possible to reduce energy consumption required for leveling the battery voltage.

  According to the second aspect of the present invention, the cell charging circuit charges the cell with the minimum charge amount, and the module discharging circuit discharges the battery module in which the voltage difference between the battery modules exceeds the reference value. Since the battery voltage in the assembled battery can be leveled, the charging / discharging device can be integrated and made compact. Furthermore, by selectively performing charging and discharging by the cell charging circuit and the module discharging circuit, it is possible to reduce energy consumption required for leveling the battery voltage.

  According to the third aspect of the present invention, it is possible to discharge all cells (that is, discharge the battery module) using all the cell discharge circuits in the battery module without using the module discharge circuit. Therefore, the charge / discharge device can be made more compact.

  According to the invention of claim 4, since the cell charging circuit realized by the two-phase pulse generation circuit is a very simple circuit, integration and miniaturization of the cell charging circuit can be easily realized.

  According to the fifth aspect of the present invention, since the charge of the capacitor can be supplied only to the cell having the minimum voltage by performing ON / OFF control of the semiconductor switching element by the logic circuit, the cell charging circuit It is greatly simplified.

  According to the invention of claim 6, since the cell voltage detection circuit detects the cell voltage of each cell and estimates the module voltage for each battery module, the voltage difference between the battery modules becomes the reference value by the module charging circuit. The battery module that has fallen below can be charged, and the cell discharge circuit can discharge the cell in which the voltage difference between the cells in the battery module exceeds the reference value. As a result, the battery voltage in the assembled battery can be leveled without providing a module voltage detection circuit or a cell selection circuit, and thus the charge / discharge device can be miniaturized.

  According to the seventh aspect of the present invention, the module charging circuit realized by the two-phase pulse generation circuit becomes very simple, so that integration and miniaturization of the module charging circuit can be easily realized.

  According to the eighth aspect of the invention, the charge of the capacitor can be supplied only to the battery module having the minimum voltage by performing ON / OFF control of the semiconductor switching element by the logic circuit, so that the module charging circuit Is greatly simplified.

Next, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.
<< First Embodiment >>
FIG. 1 is an overall configuration diagram showing a charge / discharge device 101 according to a first embodiment of the present invention.
The assembled battery 4 is a battery in which a plurality of battery modules 3 are connected in series. The battery module 3 is a battery in which a plurality of cells 2 are connected in series. The cell 2 includes one or more single batteries 1 connected in series. Or they are connected in parallel. The assembled battery 4 is connected to a load such as an electric motor and a charging mechanism such as an alternator (both not shown).

  The cell 2 is a minimum control unit of the assembled battery 4 and includes at least one unit cell 1. For example, when three cells 1 are connected in series to form a cell 2 and the rated voltage of the cell 1 is 1.5 [V], the rated voltage of the cell 2 is 4.5 [V]. .

  The battery module 3 is configured by connecting a plurality of cells 2 in series. For example, when the battery module 3 is configured by connecting four cells 2 in series, the rated voltage of the battery module 3 is 18 [V]. Furthermore, the assembled battery 4 is configured by connecting a plurality of battery modules 3 in series. For example, when three battery modules 3 are connected in series to form the assembled battery 4, the rated voltage of the assembled battery 4 is 54 [V]. In an EV car, HEV car, or FCEV car that is put into practical use, since the assembled battery 4 that is configured by connecting more battery modules 3 in series is mounted, the rated voltage of the assembled battery 4 is, for example, 150 It is about ~ 300 [V].

  Thus, (1) changing the number of cells 1 connected in series in the cell 2, (2) changing the number of cells 2 connected in series in the battery module 3, or (3) connecting in series in the assembled battery 4. The rated voltage of the assembled battery 4 can be set to a desired value by changing the number of the battery modules 3 or either.

  In addition, a cell discharge circuit CD and a cell charging circuit CC are connected in parallel to each cell 2. Further, a cell discharge circuit CD that discharges the target cell 2 or a cell selection circuit CS that selects a cell charging circuit CC that charges the target cell 2 is provided for each battery module 3. With this configuration, the cell 2 selected by the cell selection circuit CS is discharged by the cell discharge circuit CD or charged by the cell charging circuit CC, and the battery voltage leveling of each cell 2 is performed.

  In addition, a module discharge circuit MD, a module charging circuit MC, and a module voltage detection circuit MV are connected in parallel to the battery module 3, respectively. Further, a system control circuit SE to which the module discharge circuit MD, the module charging circuit MC, and the module voltage detection circuit MV are connected is provided. With this configuration, the system control circuit SE controls the module discharge circuit MD and the module charge circuit MC based on the voltage of each battery module 3 detected by the module voltage detection circuit MV, and charges / discharges the target battery module 3. The battery voltage of each battery module 3 is leveled. In addition, the circuit part comprised from the cell discharge circuit CD provided for every battery module 3, the cell charge circuit CC, the cell selection circuit CS, the module discharge circuit MD, and the module charge circuit MC is called module control circuit MS.

  In the charging / discharging device 101, the system control circuit SE sets the module charging circuit MC or the module discharging circuit MD based on the variation in the charging amount (that is, the module voltage) of each battery module 3 detected by the module voltage detecting circuit MV. The operation is performed so that the voltage variation between the battery modules 3 is leveled. In addition, when the charging / discharging electric current to each cell 2 is small, the charge condition of each cell 2 can be estimated with the voltage between terminals. The system control circuit SE has a function of calculating the charge state (charge amount) of the cell 2 based on the charge / discharge current to the cell 2 and the voltage between the terminals of the cell 2.

  In the charging / discharging device 101, the cell selection circuit CS selects the cell 2 having the maximum charge amount from each cell 2 in the battery module 3, and the cell discharge circuit CD selects the maximum charge amount selected by the cell selection circuit CS. The cell 2 is discharged. The module voltage detection circuit MV detects the module voltage for each battery module 3 in the assembled battery 4, and the system control circuit SE detects a voltage difference in the battery module 3 based on the detection result of the module voltage. The battery module 3 that has fallen below the reference value is charged by the module charging circuit MC.

  Furthermore, the cell selection circuit CS selects the cell 2 with the minimum charge amount from each cell in the battery module 3, and the cell charge circuit CC charges the cell 2 with the minimum charge amount selected by the cell selection circuit CS. . The module voltage detection circuit MV detects the module voltage for each battery module 3 in the assembled battery 4, and the system control circuit SE detects a voltage difference in the battery module 3 based on the detection result of the module voltage. The module discharge circuit MD causes the battery module 3 exceeding the reference value to be discharged.

  The configuration in which the charging / discharging device 101 equalizes the battery voltage for all the cells 2 and the battery modules 3 included in the assembled battery 4 has been described. However, the charging / discharging device 101 performs the discharge of each cell 2 and the charging of each battery module 3 by the combination of the cell discharge circuit CD and the module charging circuit MC to realize the leveling of the battery voltage, and the cell charging. The combination of the circuit CC and the module discharge circuit MD has a function of arbitrarily switching between the case where the charge for each cell 2 and the discharge for each battery module 3 are performed to realize the leveling of the battery voltage.

FIG. 2 is a circuit diagram showing in detail the maximum voltage cell discrimination circuit 10a included in the cell selection circuit CS shown in FIG.
The maximum voltage cell discriminating circuit 10a is a circuit that discriminates the cell 2 having the maximum voltage by comparing the voltages between the cells 2, and is a differential amplifier circuit that inputs the cell voltage VC of each cell 2 (see FIG. 1). 11, a maximum value circuit 12a, and a comparator circuit 13a.

  In the maximum voltage cell discriminating circuit 10a, when each cell voltage VC of the cells 2 (see FIG. 1) connected in series is applied as a potential difference to two adjacent input terminals of the differential amplifier circuit 11, Since one amplifier circuit including one operational amplifier U1 in the amplifier circuit 11 amplifies this potential difference and outputs it as a potential VC1 proportional to the cell voltage VC, this potential VC1 is applied to each operational amplifier U2 of the maximum value circuit 12a. Input to the positive terminal. The output terminal of each operational amplifier U2 has a potential corresponding to the magnitude of the input potential VC1.

  At this time, in the maximum value circuit 12a, only the NPN transistor Q1 of the system having the maximum potential VC1 (that is, the cell voltage VC is maximum) is turned on, and the other transistors Q1 are operated at the maximum potential VC1. Since the emitter voltage of the transistor Q1 (that is, the upper end voltage of the resistor R1) is high, the transistor Q1 is turned off. In this way, the maximum value signal is output from the predetermined terminal of the maximum value circuit 12a.

  Since the emitter potential of each transistor Q1 in the maximum value circuit 12a is monitored in this way, it can be determined which cell 2 has the maximum cell voltage VC. The maximum value circuit 12a is an analog OR circuit. Works as. As described above, the maximum value circuit 12a includes an amplifier circuit including the operational amplifier U2 in parallel, and is configured to selectively operate the transistor Q1 having the maximum base voltage.

  In the maximum value circuit 12a, the emitter potential of the transistor Q1 is increased only in the circuit of the system in which the potential VC1 (that is, the cell voltage VC) has the maximum value. Therefore, in the comparator circuit 13a, the potential VC1 (that is, the cell voltage VC). Only the transistor Q2 of the system with the maximum value is in the ON state. Therefore, in the comparator circuit 13a, only the negative terminal of the input of the operational amplifier U3 in which the transistor Q2 is turned on is at the ground potential, so that the output terminal of the operational amplifier U3 in that system is at the High (Hi) level. That is, in the comparator circuit 13a, the output terminal of the operational amplifier U3 having the maximum potential VC1 (that is, the cell voltage VC) is at the Hi level, and the output terminals of the operational amplifiers U3 of the other systems are at the Low (Lo) level. Become. As described above, in the maximum voltage cell discriminating circuit 10a, the output terminal of the system related to the cell 2 having the maximum voltage is set to the Hi level from the comparator circuit 13a, and the output terminals of the systems related to the other cells 2 are set to the Lo level. Sends the maximum cell discrimination signal. Therefore, the maximum voltage cell discriminating circuit 10a included in the cell selection circuit CS (see FIG. 1) can select the cell 2 having the maximum cell voltage and operate the corresponding cell discharge circuit CD.

Next, a specific example of determining the cell 2 having the minimum voltage by comparing the cell voltages VC of the cells 2 in the charge / discharge device 101 (see FIG. 1) will be described.
FIG. 3 is a circuit diagram showing in detail the minimum voltage cell discrimination circuit 10b included in the cell selection circuit CS shown in FIG.
The minimum voltage cell discriminating circuit 10b includes a differential amplifier circuit 11 for inputting a cell voltage VC, a minimum value circuit 12b, and a comparator circuit 13b. The differential amplifier circuit 11 of the minimum voltage cell discriminating circuit 10b may have the same circuit configuration as the differential amplifier circuit 11 of the maximum voltage cell discriminating circuit 10a shown in FIG.

  In the minimum voltage cell discriminating circuit 10b, when each cell voltage VC of the cells 2 (see FIG. 1) connected in series is applied as a potential difference to two adjacent input terminals of the differential amplifier circuit 11, One amplifier circuit including one operational amplifier U1 in the amplifier circuit 11 amplifies this potential difference and outputs it as a potential VC1 proportional to the cell voltage VC. Therefore, this potential VC1 is applied to each operational amplifier U2 of the minimum value circuit 12b. Input to the positive terminal. The output terminal of each operational amplifier U2 has a potential corresponding to the magnitude of the input potential VC1.

  At this time, in the minimum value circuit 12b, since the base potential of the NPN transistor Q3 of the system having the minimum potential VC1 (that is, the cell voltage VC is minimum) is the lowest, only the transistor Q3 is turned on. The transistor Q3 is turned off because the emitter voltage of the transistor Q3 operated at the minimum potential VC1 (that is, the lower end voltage of the resistor R2) is low. In this way, the minimum value signal is output from the predetermined terminal of the minimum value circuit 12b.

  Since the emitter potential of each transistor Q3 in the minimum value circuit 12b is monitored in this way, it is possible to determine which cell voltage VC is minimum, and the minimum value circuit 12b operates as an analog AND circuit. . As described above, the minimum value circuit 12b includes an amplifier circuit including the operational amplifier U2 in parallel, and is configured to selectively operate the transistor Q3 having the minimum base voltage.

  Thus, the maximum voltage cell discrimination signal obtained by the maximum voltage cell discrimination circuit 10a shown in FIG. 2 is inputted to the cell discharge circuit CD to discharge the maximum voltage cell, and the minimum voltage cell discrimination shown in FIG. By charging the minimum voltage cell by inputting the determination signal of the minimum voltage cell obtained by the circuit 10b to the cell charging circuit CC, it is possible to level the variation in the charging state between the cells 2 in the battery module 3. .

  In addition, when the charging / discharging current to the assembled battery 4 (see FIG. 1) is very large, a potential difference due to the internal resistance difference for each cell 2 is generated, and therefore there is a possibility that the determination by comparison of the voltage VC of the cell 2 cannot be performed accurately. There is. In that case, it is desirable to stop the operation of the cell charging circuit CC and the cell discharging circuit CD by the system control circuit SE.

Next, a specific example of the cell discharge circuit CD will be described.
FIG. 4 is a circuit diagram showing in detail a basic example of the cell discharge circuit CD.
When the maximum value circuit 12a in the maximum voltage cell discriminating circuit 10a shown in FIG. 2 selects the cell 2 having the maximum voltage from the plurality of cells 2, the cell discharge enable / disable signal from the system control circuit SE shown in FIG. 4 (Hi level), the cell discharge circuit CD shown in FIG. 4 includes the FETs (23a, 23b, 23c, 23d) of the system corresponding to the cell 2 having the maximum voltage among the provided FETs 23a, 23b, 23c, 23d. ) Is conducted, and the cell 2 having the maximum voltage is discharged.

  For example, in the cell discharge circuit CD of FIG. 4, when the cell discharge enable / disable signal from the system control circuit SE (see FIG. 1) is Yes (Hi level), the maximum voltage cell discrimination circuit 10a (see FIG. 2) outputs it. Only the output of the NAND circuit 21a of the detection system (that is, the detection system of the maximum voltage cell) in which the maximum cell discrimination signal is Hi level becomes the Lo level, and the outputs of the other NAND circuits 21b, 21c, and 21d become the Hi level. . Therefore, only the output of the NOT circuit 22a connected to the output of the NAND circuit 21a is at the Hi level, and the outputs of the other NOT circuits 22b, 22c, and 22d are at the Lo level. As a result, only the FET 23a connected in parallel to the maximum voltage cell 2a becomes conductive, and the other FETs 23b, 23c, and 23d become non-conductive, so that only the maximum voltage cell 2a is discharged by the resistor R3 through the FET 23a. Is done.

Next, a specific example of the module discharge circuit MD will be described.
FIG. 5 is a circuit diagram showing an example of the module discharge circuit MD.
When the module discharge command signal from the system control circuit SE (see FIG. 1) is at the Hi level, the output of the buffer 22 in the module discharge circuit MD is at the Hi level, causing the FET 23 to conduct, and the cells 2a, 2b, 2c, 2d. The battery module 3a made of is discharged.

FIG. 6 is a circuit diagram showing a modification of the cell discharge circuit CD.
If a modification of the cell discharge circuit CD shown in FIG. 6 is used instead of the basic example of the cell discharge circuit CD shown in FIG. 4, the module discharge circuit MD (see FIG. 5) can be used without the module discharge circuit MD (see FIG. 5). Since all the cells 2a, 2b, 2c, 2d can be discharged at the same time, the module discharge circuit MD can be omitted.

  6 is different from the basic example of the cell discharge circuit CD shown in FIG. 4 in that OR circuits 24a, 24b, 24c, and 24d are added, and these OR circuits 24a, 24b, 24c, and 24d are added. In either case, the battery module discharge command signal is input. For example, in this cell discharge circuit CD, when the cell discharge enable / disable signal from the system control circuit SE (see FIG. 1) is possible (Hi level), the maximum output from the maximum voltage cell discriminating circuit 10a (see FIG. 2). Only the output of the NAND circuit 21a of the detection system in which the cell discrimination signal is Hi level (that is, the detection system of the maximum voltage cell) is Lo level, and the outputs of the other NAND circuits 21b, 21c, and 21d are Hi level. Therefore, only the output of the NOT circuit 22a connected to the output of the NAND circuit 21a is at the Hi level, and the outputs of the other NOT circuits 22b, 22c, and 22d are at the Lo level.

  On the other hand, OR circuits 24a, 24b, 24c, and 24d are connected to the output side of the NOT circuits 22a, 22b, 22c, and 22d, and a battery module discharge command signal is further input. Therefore, even if the Hi level and Lo level signals of the maximum cell discrimination signal are mixedly input to one input terminal of each of the OR circuits 24a, 24b, 24c, and 24d, the OR circuits 24a, 24b, and 24c. 24d, the Hi-level battery module discharge command signal is input to the other input terminal, so that Hi-level signals are output from the output terminals of all the OR circuits 24a, 24b, 24c, and 24d. Thus, since all the FETs 23a, 23b, 23c, and 23d are in the ON state, all the cells 2a, 2b, 2c, and 2d can be discharged by simultaneously making the cell discharge circuit CD conductive, and the module discharge circuit MD is omitted. can do.

Next, a specific example of the cell charging circuit CC will be described.
FIG. 7 is a circuit diagram showing in detail an example of the cell charging circuit CC.
In this cell charging circuit CC, the two-phase pulses generated by the two-phase pulse generation circuits P31 and P32 are rectified by the diode bridges 33a, 33b, 33c and 33d, charged by the capacitors 34a, 34b, 34c and 34d, respectively, and output. Thus, the DC power for charging the cells 2a, 2b, 2c, and 2d is obtained.

  At this time, when the minimum value circuit 12b in the minimum voltage cell discriminating circuit 10b (see FIG. 3) selects the cell 2a having the minimum voltage from the plurality of cells 2a, the cell from the system control circuit SE (see FIG. 1). If the charge enable / disable signal is enabled (Hi level), the cell charging circuit CC shown in FIG. 7 conducts the FET of the system corresponding to the cell 2a having the minimum voltage among the provided FETs, and sets the minimum voltage. The cell 2a is charged.

  For example, in the cell charging circuit CC, when the cell discharge enable / disable signal from the system control circuit SE (see FIG. 1) is “Yes” (Hi level), the minimum voltage output from the minimum voltage cell determination circuit 10b (see FIG. 3). Only the output of the NOT circuit 31a of the detection system in which the cell discrimination signal is at the Lo level (that is, the detection system of the minimum voltage cell) is at the Hi level, and the outputs of the other NOT circuits 31b, 31c, 31d are at the Lo level. Accordingly, only the output of the AND circuit 32a is at the Hi level, and the outputs of the other AND circuits 32b, 32c, and 32d are at the Lo level. As a result, only the FETs 35a and 36a connected to the system of the cell 2a having the minimum voltage are turned on, and the other FETs 35b, 35c and 35d and the FETs 36b, 36c and 36d are turned off. Accordingly, only the cell 2a having the minimum voltage is charged through the FETs 35a and 36a.

Next, a specific example of the module charging circuit MC will be described.
FIG. 8 is a circuit diagram showing in detail an example of the module charging circuit MC.
In this module charging circuit MC, when the module discharge command signal from the system control circuit SE (see FIG. 1) is at the Hi level, the FETs 35 and 36 are turned on, so that the pulses from the two-phase pulse generation circuits P31 and P32 are diode bridges. 33 is rectified, charged by the capacitor 34 and output, and charged to the battery module 3a.

  The module charging circuit MC shown in FIG. 8 is similar to the cell charging circuit CC shown in FIG. 7, but the DC power voltage required for charging the battery module 3a is required for charging the cells 2a, 2b, 2c, and 2d. Therefore, the amplitudes of the two-phase pulses generated by the two-phase pulse generation circuits P31 and P32 are individually set in the module charging circuit MC and the cell charging circuit CC. Therefore, separate two-phase pulse generation circuits P31 and P32 are used for the cell 2a and the battery module 3, respectively.

  In this module charging circuit MC, the operating power of the module control circuit MS (see FIG. 1) can be taken out from the connection point A between the diode bridge 33 and the FET 35. If the two-phase pulse generation circuits P31 and P32 are controlled by the system control circuit SE (see FIG. 1), the two-phase pulse generation circuits P31 and P32 may be operated only when it is desired to operate the module control circuit MS. When the cell charge enable / disable signal from the system control circuit SE (see FIG. 1) is NO (Lo level), the module control circuit MS and the cells 2a, 2b, 2c, 2d are separated by the FETs 35, 36. For example, EV The electrical system (not shown) of cars, HEV cars, and FCEV cars does not operate. Therefore, even if these vehicles (not shown) are left unattended, the module control circuit MS is prevented from consuming the power of the assembled battery 4 (see FIG. 1).

FIG. 9 is a circuit diagram showing in detail an example of the module voltage detection circuit MV.
The module voltage detection circuit MV is based on a voltage detection method known as a flying capacitor circuit. That is, module voltages having different potentials are connected via the capacitor 45 by alternately turning on the photoMOS relays 41 and 42 and the photoMOS relays 43 and 44 by the control signals (Port A and Port B) from the system control circuit SE. By transferring Vm to the system control circuit SE, the module voltage Vm of the battery module 3a can be detected by the system control circuit SE.

  That is, by inputting the analog outputs of the maximum value circuit 12a of the maximum voltage cell discrimination circuit 10a (see FIG. 2) and the minimum value circuit 12b of the minimum voltage cell discrimination circuit 10b (see FIG. 3) to the operational amplifier 46 shown in FIG. When the voltage indicating the variation amount of the cell voltage VC of each cell 2a, 2b, 2c, 2d in the battery module 3a is received by the system control circuit SE, the cell of each cell 2a, 2b, 2c, 2d in the battery module 3a Whether the voltage VC needs to be leveled can be detected.

  Here, if leveling of the cell voltages VC of the cells 2a, 2b, 2c, and 2d is not required, the cell discharge enable / disable signal (see FIG. 4) from the system control circuit SE (see FIG. 1) is rejected (see FIG. 4). Lo), or the cell charge enable / disable signal (see FIG. 7) from the system control circuit SE (see FIG. 1) is kept in the no (Lo) state, thereby constituting a large number of cells 2. It is possible to prevent the module control circuit MS from inadvertently malfunctioning due to charging / discharging current to the assembled battery 4 or disturbance noise.

  Further, in the module control circuit MS (see FIG. 1), the cell charge / discharge is stopped when the variation amount of the cell 2 is small, and the same is true even if there is no instruction signal from the system control circuit SE (see FIG. 1). The effect of can be obtained. In this case, the analog signal of the maximum value circuit 12a of the maximum voltage cell discrimination circuit 10a shown in FIG. 2 and the minimum value circuit 12b of the minimum voltage cell discrimination circuit 10b shown in FIG. 3 is compared with a predetermined reference voltage. The cell 2 with a small charge amount in the battery module 3 and the cell 2 with a large charge amount can be detected.

  In addition to the configuration in which the module voltage of each battery module 3 is compared with a predetermined reference voltage as described above, the same effect can be obtained by a configuration in which the cell voltage VC for each cell 2 is compared with a predetermined reference voltage. It is done. In the configuration in which the cell voltage VC is compared with a predetermined reference voltage, as many voltage comparison circuits as the number of cells 2 are required. Therefore, the maximum value circuit 12a (see FIG. 2) and the minimum value circuit 12b (see FIG. 3) are provided. The configuration used can reduce the number of parts.

<< Second Embodiment >>
FIG. 10 is an overall configuration diagram showing the charging / discharging device 102 of the second embodiment according to the present invention.
This charging / discharging device 102 is provided with a cell voltage detection circuit CV for each cell 2 instead of the module voltage detection circuit MV provided for each battery module 3 in the charging / discharging device 101 of the first embodiment shown in FIG. It has a configuration excluding the cell selection circuit CS provided for each battery module 3.

  The system control circuit SE inputs the cell voltage VC of each cell 2 detected by the cell voltage detection circuit CV, the cell 2 having a large charge amount is discharged by the cell discharge circuit CD, and the cell 2 having a small charge amount is charged by the cell. It is charged by the circuit CC. At this time, the system control circuit SE estimates the charge amount in the unit of the battery module 3 from the cell voltage VC of each cell 2 detected by each cell voltage detection circuit CV, and the module charging circuit MC and the module discharging circuit MD respectively. The battery module 3 is charged and discharged to level the entire assembled battery 4.

  In the charging / discharging device 101 (see FIG. 1) of the first embodiment described above, in the cell charging circuit CC (see FIG. 7), the diode bridges 33a, 33b, 33c, 33d and the cells 2a, 2b, 2c, 2d, respectively, In the charging / discharging device 102 (see FIG. 10) of the second embodiment, the switching element (FETs 35a, 35b, 35c, 35d, 36a, 36b, 36c, 36d) is inserted between and the charging control is performed. Two-phase pulse generation circuits P31 and P32 (see FIG. 7) are made independent for each cell 2, and the presence or absence of charging to the cell 2 is controlled by the presence or absence of a pulse. In that case, the switching elements (FETs 35a, 35b, 35c, 35d, 36a, 36b, 36c, 36d) can be omitted.

<< Modification of Embodiment >>
In the charging / discharging device 101 (see FIG. 1) of the first embodiment or the charging / discharging device 102 (see FIG. 2) of the second embodiment, when the variation of the cell voltage VC is small in each cell 2 in the battery module 3 Either the cell charging circuit CC or the cell discharging circuit CD may be omitted. This is because in this case, since the adjustment amount of the charge state by charging / discharging between the cells 2 is small, the cell 2 having a small charge amount is charged by the cell charging circuit CC or the cell having a large charge amount by the cell discharge circuit CD. This is because the battery pack 4 can be leveled without significantly increasing the power loss if either one of the two is discharged.

  Further, when the variation of each cell 2 in the battery module 3 is relatively large and the adjustment amount of charging / discharging between the battery modules 3 and the adjustment amount of charging / discharging between the cells are not so different, the module is determined by the cell discharge circuit CD. The discharge circuit MD may be substituted. Alternatively, the module charging circuit MC may be replaced by the cell charging circuit CC. In these cases, either one of the cell charging circuit CC or the cell discharging circuit CD is a circuit in units of 2 cells, and the other is a circuit in units of the battery module 3, thereby reducing the number of parts and suppressing manufacturing costs. .

  For example, the cell discharge circuit CD and the module charging circuit MC may be combined to discharge the cells 2 and charge the battery modules 3 to level the battery voltage. A combination of the discharge circuit MD and the charge for each cell 2 and the discharge for each battery module 3 may be used to level the battery voltage.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram which shows the charging / discharging apparatus of 1st Embodiment by this invention. FIG. 2 is a circuit diagram showing in detail a maximum voltage cell discrimination circuit provided in the cell selection circuit shown in FIG. 1. FIG. 2 is a circuit diagram showing in detail a minimum voltage cell discrimination circuit provided in the cell selection circuit shown in FIG. 1. It is a circuit diagram which shows the basic example of a cell discharge circuit in detail. It is a circuit diagram which shows an example of a module discharge circuit. It is a circuit diagram which shows the modification of a cell discharge circuit. It is a circuit diagram which shows an example of a cell charging circuit in detail. It is a circuit diagram which shows an example of a module charging circuit in detail. It is a circuit diagram which shows an example of a module voltage detection circuit in detail. It is a whole block diagram which shows the charging / discharging apparatus of 2nd Embodiment by this invention.

Explanation of symbols

1 unit cell 2a, 2b, 2c, 2d cell 3, 3a battery module 4 assembled battery 10a maximum voltage cell discrimination circuit 10b minimum voltage cell discrimination circuit 11 differential amplifier circuit 12a maximum value circuit 12b minimum value circuit 13a, 13b comparator circuit 21a, 21b, 21c, 21d, NAND circuit 22 buffer 22a, 22b, 22c, 22d, 31a, 31b, 31c, 31d NOT circuit 23, 23a, 23b, 23c, 23d FET
24a, 24b, 24c, 24d OR circuit 32a, 32b, 32c, 32d AND circuit 33, 33a, 33b, 33c, 33d Diode bridge 34, 34a, 34b, 34c, 34d, 45 Capacitor 35, 35a, 35b, 35c, 35d 36a, 36b, 36c, 36d FET
41, 42, 43, 44 Photo MOS relay CC cell charging circuit CD cell discharging circuit CS cell selection circuit CV cell voltage detection circuit MC module charging circuit MD module discharging circuit MS module control circuit MV module voltage detecting circuit P31, P32 Two-phase pulse Generator circuit SE system control circuit

Claims (8)

A charging / discharging device that is connected to an assembled battery formed by connecting a plurality of battery modules composed of a plurality of cells in series, and performs charging / discharging of the cell or the battery module according to a charging state of the cell or the battery module. ,
A cell voltage detection circuit for detecting a cell voltage for each of the cells in the battery module;
A cell selection circuit for selecting a cell with the maximum charge amount between each cell in the battery module;
A cell discharge circuit that is provided for each cell and discharges a cell having a maximum charge amount selected by the cell selection circuit;
A module voltage detection circuit for detecting a module voltage for each battery module in the assembled battery;
A module charging circuit that is provided for each battery module and charges the corresponding battery module;
Based on the detection result of the module voltage by the module voltage detection circuit, a system control circuit that causes the module charging circuit to charge the battery module in which the voltage difference between the battery modules is lower than a reference value;
A charge / discharge device comprising: A charging / discharging device that is connected to an assembled battery formed by connecting a plurality of battery modules composed of a plurality of cells in series, and performs charging / discharging according to a charging state of the cell or the battery module,
A cell voltage detection circuit for detecting a cell voltage for each of the cells in the battery module;
A cell selection circuit for selecting a cell with the minimum charge amount between each cell in the battery module;
A cell charging circuit that is provided for each cell and charges a cell of the minimum charge amount selected by the cell selection circuit;
A module voltage detection circuit for detecting a module voltage for each battery module in the assembled battery;
A module discharge circuit that is provided for each battery module and discharges the corresponding battery module;
Based on the module voltage detection result by the module voltage detection circuit, a system control circuit that causes the module discharge circuit to discharge the battery module in which the voltage difference between the battery modules exceeds a reference value;
A charge / discharge device comprising:   The system control circuit causes each battery discharge circuit to discharge a battery module in which a voltage difference between the battery modules exceeds a reference value by detecting a module voltage by the module voltage detection circuit. The charging / discharging device according to claim 1. The cell charging circuit includes:
A two-phase pulse generation circuit for complementary output of two types of pulses with different time axes;
A diode bridge for rectifying each of the two types of pulses;
A capacitor that charges and outputs the electric power of the two types of pulses generated by the two-phase pulse generation circuit via the diode bridge;
A current limiting element for suppressing an inrush current to the capacitor;
A semiconductor switching element that is provided between the cell and the capacitor and supplies / cuts off the charging energy stored in the capacitor by ON / OFF control;
The charge / discharge device according to any one of claims 1 to 3, further comprising:   5. The charging according to claim 4, wherein the semiconductor switching element performs charging / discharging of the cell by ON / OFF control based on a cell charging enable / disable signal and a minimum voltage cell determination signal. Discharge device. A charging / discharging device that is connected to an assembled battery formed by connecting a plurality of battery modules composed of a plurality of cells in series, and performs charging / discharging according to a charging state of the cell or the battery module,
A cell voltage detection circuit that performs voltage detection for each cell in the battery module;
A cell discharge circuit which is provided for each cell and discharges the corresponding cell;
A module charging circuit that is provided for each battery module and charges the corresponding battery module;
Based on the detection result of each cell voltage and module voltage by the cell voltage detection circuit, the battery module in which the voltage difference between the battery modules is below a reference value is charged using the module charging circuit, and the battery A system control circuit that causes the cell discharge circuit to discharge a cell in which a voltage difference between cells in the module exceeds a reference value;
A charge / discharge device comprising: The module charging circuit is
A two-phase pulse generation circuit for complementary output of two types of pulses with different time axes;
A diode bridge provided for each module charging circuit and rectifying the two types of pulses;
A capacitor that is provided for each module charging circuit and that charges and outputs the electric power of the two types of pulses generated by the pulse generation circuit via the diode bridge;
A current limiting element that is provided for each module charging circuit and suppresses an inrush current to the capacitor;
A semiconductor switching element which is provided between the battery module and the capacitor and supplies / cuts off the charging energy stored in the capacitor by ON / OFF control;
The charge / discharge device according to claim 6, comprising:   The said semiconductor switching element performs implementation / non-implementation of the said battery module by ON / OFF control based on a cell charge availability signal and a minimum voltage cell discrimination signal. Charge / discharge device.

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