JP2005151720A - Cell balance correcting device, secondary battery, method of correcting cell balance and cell balance correcting program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cell balance correcting device which can correct a cell balance at a secondary battery charging/discharging time and to provide a secondary battery, a method of correcting the cell balance and a cell balance correcting program. <P>SOLUTION: The cell balance correcting device includes a constant current source 20 for supplying an extrapolating current for extrapolating the charging/discharging current of a plurality of batteries 10 for constituting a series battery 100, and a plurality of voltage sensors 30 for measuring the voltage values of the plurality of the batteries 10. A voltage monitor 40 for inputting the voltage values of the plurality of the batteries 10 from the plurality of the voltage sensors 30, comparing the voltage values of the plurality of the batteries 10, and starting the constant current source 20, thereby correcting the cell balance. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a power storage device, UPS (uninterruptible
Rechargeable batteries for emergency power supplies such as power supplies (uninterruptible power supplies) and HEV (Hybrid Electric)
The present invention relates to a cell balance correction device, a secondary battery, a cell balance correction method, and a cell balance correction program used in a secondary battery for a mobile object such as a vehicle (hybrid electric vehicle) and an electric forklift.

When a secondary battery is overcharged or overdischarged, life deterioration and safety problems occur. In series battery systems, due to variations in the capacity of individual batteries, even if the same power is charged / discharged, some batteries will be overcharged / overdischarged, so a mechanism to correct the voltage balance of each battery is required. Become.
As a cell balance correction method, it is conventionally known to correct the voltage balance of a series battery using a capacitor. For example, Patent Literature 1 discloses a charge / discharge control device using a capacitor. According to the present invention, a plurality of unit capacitors are connected in series as a cell to form a combined power source, and an adjustment cell that can be charged / discharged with respect to each cell of the combined power source and the adjustment cell individually And connecting means for controlling the connecting means so that the adjustment cell is connected to each cell of the assembled power supply in order (see FIG. 7).
By comprising in this way, the voltage of each cell is equalized by charging / discharging between the cell for adjustment and each cell, and the overdischarge and the overcharge by the capacity variation of a cell are prevented.
JP 2003-189495 A

  According to the above-described invention, the balance circuit can be configured at low cost. However, when this method is applied to a large-capacity battery, there is a problem that it is difficult to reduce the size because a large capacitor is required as the adjustment cell.

The present invention has been made in view of such circumstances, and a first object is to provide a cell balance correction apparatus, a cell balance correction method, and a cell balance correction method capable of correcting cell balance during charging and discharging of a secondary battery. It is to provide a cell balance correction program.
A second object is to provide a cell balance correction device, a cell balance correction method, and a cell balance correction program capable of realizing cell balance correction of a large-capacity series battery with a small circuit.

  The present invention has been made to solve the above problems, and the present invention provides a constant current source that supplies a complementary current that complements charging / discharging currents of a plurality of batteries constituting a series battery, and voltages of the plurality of batteries. A plurality of voltage sensors for measuring values, and voltage monitoring for inputting the voltage values of the plurality of batteries from the plurality of voltage sensors, comparing the voltage values of the plurality of batteries, and starting the constant current source Means.

  Further, according to the present invention, one constant current source is provided corresponding to one battery constituting the series battery, and the voltage monitoring unit is configured to output voltage values of the plurality of batteries from the plurality of voltage sensors. And a voltage value of each of the plurality of batteries is compared, and a constant current source corresponding to a battery whose voltage value is lower than a set value by a value higher than the highest voltage battery is started.

  According to the present invention, one constant current source is provided corresponding to a group consisting of a plurality of batteries among all the batteries constituting the series battery, and the switching means is controlled by the voltage monitoring means. Supplying a complementary current that complements the charging / discharging current of one battery among the plurality of batteries constituting the group, and the voltage monitoring means includes a plurality of batteries constituting the group from the plurality of voltage sensors, respectively. A constant current source corresponding to the battery with the lowest voltage value among the batteries whose voltage value is lower than the highest voltage by a set value or more. It is characterized by starting.

  In the present invention, the voltage monitoring means further outputs a current command corresponding to a voltage difference between a battery having the highest voltage value and a battery that activates the constant current source to the activated constant current source. And

  Further, according to the present invention, the voltage monitoring unit is configured such that when the voltage difference between the battery having the highest voltage value and the battery that activates the constant current source is larger than a threshold, the current is lower than the current command corresponding to the voltage difference A current command indicating a value is output to the activated constant current source.

  Further, the present invention further includes one or a plurality of current sensors for measuring charge / discharge currents of a plurality of batteries constituting the series battery, and the voltage monitoring unit uses the charge / discharge current values measured by the current sensors. It is input, and a current command corresponding to the voltage difference and the charge / discharge current value is output to the activated constant current source.

  In the invention, it is preferable that the constant current source is supplied with a driving current from the series battery.

  Further, the present invention is characterized in that the constant current source is supplied with a drive current from a predetermined external power supply device.

  Moreover, the secondary battery of this invention is equipped with the said cell balance correction apparatus, It is characterized by the above-mentioned.

  Further, according to the present invention, the plurality of voltage sensors measure the voltage value of each of the plurality of batteries constituting the series battery, input the voltage value of each of the plurality of measured batteries, and the voltage value of each of the plurality of batteries. And starting a constant current source for supplying a complementary current that complements the charging / discharging currents of a plurality of batteries constituting the series battery.

  Further, the present invention compares the process of inputting each voltage value from a plurality of voltage sensors provided in each of a plurality of batteries constituting a series battery, and the voltage value of each of the input plurality of batteries, It is a cell balance correction program for making a computer perform the process which starts the constant current source which supplies the complementary current which supplements the charging / discharging current of the some battery which comprises a series battery.

As described above, according to the present invention, a plurality of voltage sensors measure a voltage value of each of a plurality of batteries constituting a series battery, and a voltage value of each of the plurality of batteries is compared to constitute a series battery. A constant current source that supplies a complementary current that supplements the charging / discharging currents of a plurality of batteries is activated.
By comprising in this way, the supplementary electric current which complements the charging / discharging electric current of a battery is supplied based on the voltage value of each of the some battery which comprises a series battery at the time of charging / discharging.
Therefore, at the time of charging, in addition to the charging current from the charger, the complementary current from the constant current source flows to the corresponding battery, so that an effect of eliminating the voltage difference from other batteries can be obtained.
Further, at the time of discharging, the current flows from the constant current source connected to the corresponding battery to the load, so that the discharge current of the battery itself is reduced and the voltage difference is eliminated.
Moreover, since the voltage of a series battery is equalized only by the loss of a constant current source by comprising in this way, the effect which can improve the cell balance efficiency at the time of charging / discharging is acquired.
Also, with this configuration, the voltage of the series battery is equalized only by the constant current source and the control circuit that controls the constant current source instead of the capacitor, so that the effect of reducing the size of the device can be obtained. It is done.

According to the present invention, it is also possible to provide one constant current source corresponding to a group consisting of a plurality of batteries among all the batteries constituting the series battery. In this case, switching control is performed by the voltage monitoring means. The supplementary electric current which supplements the charging / discharging electric current of one battery among the some batteries which comprise a group is supplied through the switching means to be performed.
Therefore, since the number of constant current source circuits can be reduced, an effect that the manufacturing cost can be greatly reduced is obtained.

Further, according to the present invention, the voltage monitoring means has a current value lower than the current command corresponding to the voltage difference when the voltage difference between the battery having the highest voltage value and the battery that activates the constant current source is larger than the threshold value. Is output to the activated constant current source.
With this configuration, a large current does not flow through the battery even when the voltage difference is large.
Therefore, an electronic element used in the constant current source circuit can be a low-cost electronic element having a small current value, and an effect of preventing a decrease in charge / discharge efficiency due to a large current flowing can be obtained.

Further, according to the present invention, one or more current sensors for measuring charge / discharge currents of a plurality of batteries constituting the series battery are further provided, and the voltage monitoring means inputs the charge / discharge current values measured by the current sensors. The current command corresponding to the voltage difference and the charge / discharge current value is output to the activated constant current source.
Therefore, since a low complementary current corresponding to a low load can be supplied at the time of discharging, an effect of efficiently equalizing the voltage of the series battery can be obtained even when the load is low.

  Hereinafter, the best mode for carrying out the present invention will be described.

<First Embodiment>
Hereinafter, an embodiment of a cell balance correction apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of the cell balance correction apparatus of the present embodiment.
As shown in FIG. 1, the cell balance correction apparatus of the present embodiment provides a complementary current that complements a charging current and a discharging current during charging / discharging with respect to a series battery 100 in which a plurality of cells (batteries) 10 are connected in series. The cell balance is adjusted by supplying.
Specifically, the cell balance correction apparatus according to the present embodiment includes a plurality of constant current sources 20, a plurality of voltage sensors 30, a voltage monitoring unit 40, and an insulation type DC / DC converter 50.
The constant current source 20 corresponds to all the batteries 10 constituting the series battery 100, that is, one constant current source 20 is provided for one battery 10 and supplies a complementary current that complements the charge / discharge current of the corresponding battery 10. To do. The constant current source 20 is configured using, for example, an amplifier, a constant voltage element, a transistor, and the like as shown in FIGS. 2 and 3, and controls the current value of the complementary current to be output to the battery 10. In addition to the above, a specific configuration example of the constant current source 20 may be configured by using a dedicated IC for battery charging control, for example. Is something that can be done. The constant current source 20 is connected to the series battery 100 via the insulation type DC / DC converter 50, and receives a drive current from the series battery 100.

Similarly to the constant current source 20, the voltage sensor 30 corresponds to all the batteries 10 constituting the series battery 100, that is, one voltage sensor 30 is provided for one battery 10 and measures the voltage value of the corresponding battery 10. And output to the voltage monitoring unit 40.
The voltage monitoring unit 40 is composed of one or a plurality of logic circuits having a CPU and other voltage comparison circuits. The voltage monitoring unit 40 inputs the voltage values of all the batteries 10 from all the voltage sensors 30, and the voltages of all the batteries 10. The values are compared, and an activation signal for activating the constant current source 20 is output according to the conditions set at the time of charging / discharging. Specifically, the voltage monitoring unit 40 compares the input voltage values, and outputs an activation signal for activating the constant current source 20 corresponding to a battery whose voltage value is lower than a set value by a value higher than the highest voltage battery. . For example, at the time of charging, the voltage monitoring unit 40 outputs an activation signal for activating the constant current source 20 corresponding to the battery 10 having a voltage 25 mV (millivolt) or more lower than the highest voltage battery 10 in the series battery 100. On the other hand, at the time of discharging, the voltage monitoring unit 40 outputs an activation signal for activating the constant current source 20 corresponding to the battery 10 whose voltage is 25 mV (millivolt) or lower than the highest voltage battery 10 in the series battery 100.
The insulated DC / DC converter 50 steps down the total battery voltage input from the series battery 100 and supplies it to the constant current source 20.

Next, the operation of the cell balance correction apparatus of this embodiment will be described.
First, at the time of charging, the series battery 100 is connected to a charger, and charging current is supplied to all the batteries 10. At this time, the voltage values measured from all the voltage sensors 30 to the voltage monitoring unit 40 are constantly output, and the voltage values input by the voltage monitoring unit 40 are compared. And the voltage monitoring part 40 selects the battery 10 whose voltage is 25 mV (millivolt) or more lower than the battery 10 of the highest voltage among the input voltage values.
Even when there are a plurality of batteries 10 whose voltages are 25 mV (millivolt) or more lower than the highest voltage battery 10, the voltage monitoring unit 40 activates the constant current sources corresponding to all the corresponding batteries.
When a limit on the number of constant current sources to be activated is set in advance, an activation signal for activating the constant current sources 20 corresponding to the limited number of batteries is output from the lowest voltage value.
When the constant current source 20 is activated, the supplementary current supplied from the constant current source 20 flows to the corresponding battery 10 in addition to the charging current supplied from the charger, so that no other supplemental current is supplied. Charging is accelerated compared to 10, and the voltage difference is eliminated.
When the voltage difference becomes 15 mV or less, the constant current source 20 corresponding to the battery is stopped. When the number of constant current sources to be started is limited, instead of the stopped constant current source, the battery with the next lowest voltage value among the batteries whose voltage value is 25 mV (millivolt) or more lower than the highest voltage battery The constant current sources 20 corresponding to 10 are sequentially activated.
Note that frequent switching is prevented by providing hysteresis to the start / stop voltage.

On the other hand, at the time of discharging, series battery 100 is connected to a load and supplies a discharging current. Similarly, the voltage values measured from all the voltage sensors 30 to the voltage monitoring unit 40 are always output at this time, and the voltage values input by the voltage monitoring unit 40 are compared. And the voltage monitoring part 40 selects the battery 10 whose voltage is 25 mV (millivolt) or more lower than the battery 10 of the highest voltage among the input voltage values.
Even when there are a plurality of batteries 10 whose voltages are 25 mV (millivolt) or more lower than the highest voltage battery 10, the voltage monitoring unit 40 activates the constant current sources corresponding to all the corresponding batteries.
When a limit is set in advance for the number of constant current sources to be activated, an activation signal for activating the constant current sources 20 corresponding to the limited number of batteries is output from the lowest voltage value. When the constant current source 20 is activated, a complementary current flows from the constant current source 20 connected to the corresponding battery 10 to the load, so that the discharge current of the battery 10 itself is reduced compared to the battery 10 to which no other complementary current is supplied. However, the voltage difference will disappear.
When the voltage difference becomes 15 mV or less, the constant current source 20 corresponding to the battery is stopped. When the number of constant current sources to be started is limited, instead of the stopped constant current source, the battery with the next lowest voltage value among the batteries whose voltage value is 25 mV (millivolt) or more lower than the highest voltage battery The constant current sources 20 corresponding to 10 are sequentially activated.
By giving hysteresis to the start / stop voltage, frequent switching is prevented in the same way as during charging.

As described above, according to the cell balance correction apparatus of the present embodiment, the plurality of voltage sensors 30 measure the voltage values of the plurality of batteries 10 constituting the series battery 100, and the voltages of the plurality of batteries 10 respectively. The values are compared, and an activation signal for activating the constant current source 20 that supplies a complementary current that complements the charge / discharge current is output.
By comprising in this way, the supplementary electric current which supplements the charging / discharging electric current of the battery 10 is supplied based on each voltage value of the some battery 10 which comprises the series battery 100 at the time of charging / discharging. Therefore, at the time of charging, in addition to the charging current from the charger, the complementary current from the constant current source 20 flows to the corresponding battery 10, so that the effect of eliminating the voltage difference from the other batteries 10 can be obtained. Further, at the time of discharging, the current flows from the constant current source 20 connected to the corresponding battery 10 to the load, so that the discharge current of the battery itself is reduced and the voltage difference is eliminated.
Moreover, since the voltage of the series battery 100 is equalized only by the loss of the constant current source 20 by comprising in this way, the effect which can improve the cell balance efficiency at the time of charging / discharging is acquired.
Further, with this configuration, the voltage of the series battery 100 is equalized only by the constant current source 20 and the voltage monitoring circuit 40 that controls the constant current source 20 instead of the capacitor, so that the size of the device can be reduced. The effect that can be obtained.
Furthermore, by limiting the number of constant current sources to be activated, it is possible to suppress deterioration in efficiency and temperature rise in the apparatus due to loss of the constant current source.

<Second Embodiment>
Hereinafter, a second embodiment of the cell balance correction apparatus of the present invention will be described with reference to the drawings. FIG. 4 is a configuration diagram of the cell balance correction apparatus of the present embodiment. The cell balance correction apparatus of this embodiment is different from the first embodiment in that the constant current source 20 is not provided for all the batteries 10, but all the batteries constituting the series battery 100 are replaced by a plurality of batteries 10. And a single constant current source 20 is provided for a plurality of batteries 10 belonging to this group. Hereinafter, regarding the cell balance correction apparatus of the present embodiment, description of points that are common to the first embodiment will be omitted, and only differences will be described.
As shown in FIG. 4, the cell balance correction apparatus of this embodiment divides the series battery 100 into a plurality of groups N (in FIG. 4, only the groups K and K + 1 are shown as an example), and a plurality of batteries belonging to each group. For 10, the cell balance is corrected for each group. That is, one constant current source 20 is provided corresponding to a group consisting of a plurality of batteries 10 among all the batteries constituting the series battery 100. Each constant current source 20 is connected to a plurality of batteries 10 in the group via a switch 60. The switch 60 is switch-controlled by the voltage monitoring unit 40 and supplies a complementary current input from the constant current source 20 to one of the batteries 10 in the group.
The voltage monitoring unit 40 inputs the voltage values of all the batteries 10 in the group from all the voltage sensors 30 in the group, compares the respective voltage values, and according to the conditions set at the time of charging / discharging. An activation signal for activating any constant current source 20 is output. Note that a predetermined number of voltage monitoring units 40 are appropriately provided depending on the implementation. Specifically, the voltage monitoring units 40 are provided corresponding to each group, or the voltage monitoring unit 40 is provided in the apparatus to centrally monitor and control the voltages of all groups. It is conceivable to provide one.

Next, the operation of the cell balance correction apparatus of this embodiment will be described.
First, at the time of charging, the series battery 100 is connected to a charger, and charging current is supplied to all the batteries 10. At this time, in each of the groups 1 to N, the voltage values measured from all the voltage sensors 30 in the group to the voltage monitoring unit 40 of each group are always output, and the voltage values input by the voltage monitoring unit 40 are compared. . And the voltage monitoring part 40 selects the battery 10 whose voltage is 25 mV (millivolt) lower than the battery 10 of the highest voltage among the input voltage values from each group.
If there is one battery 10 in each group whose voltage is 25 mV (millivolt) or more lower than the highest voltage battery 10, the voltage monitoring unit 40 activates the constant current source 20 corresponding to this battery 10 and a switch 60 switching signals are output. On the other hand, when there are a plurality of batteries 10 having a voltage of 25 mV (millivolt) or more lower than that of the highest voltage battery 10 in each group, the voltage monitoring unit 40 sequentially determines the voltage corresponding to the battery 10 having the lowest voltage value in each group. An activation signal for activating the current source 20 and a switching signal for the switch 60 are output. When the constant current source 20 corresponding to the battery 10 having the lowest voltage value in each group is activated, the corresponding battery 10 is supplied from the constant current source 20 via the switch 60 in addition to the charging current supplied from the charger. When the supplied complementary current flows, charging is accelerated compared to other batteries 10 to which no complementary current in the group is supplied, and the voltage difference is eliminated. Then, when the voltage difference becomes 15 mV or less, the constant current source 20 is stopped in each group, and the constant current source 20 corresponding to the battery 10 having the next lowest voltage value is sequentially started in each group. Thus, hysteresis is given to the starting voltage. With this configuration, frequent switching within each group is prevented.

On the other hand, at the time of discharging, series battery 100 is connected to a load and supplies a discharging current. At this time, similarly, the voltage values measured from all the voltage sensors 30 in the group are constantly output to the voltage monitoring unit 40, and the voltage values input by the voltage monitoring unit 40 are compared. And the voltage monitoring part 40 selects the battery 10 whose voltage is 25 mV (millivolt) lower than the battery 10 of the highest voltage among the input voltage values in each group.
If there is one battery 10 whose voltage is 25 mV (millivolt) or more lower than the highest voltage battery 10, the voltage monitoring unit 40 activates the constant current source 20 corresponding to this battery 10 and the switch 60 switching signal. Is output. On the other hand, when there are a plurality of batteries 10 whose voltage is 25 mV (millivolt) or more lower than the highest voltage battery 10, the voltage monitoring unit 40 sequentially activates the constant current source 20 corresponding to the battery 10 having the lowest voltage value. And a switching signal of the switch 60 is output. When the constant current source 20 corresponding to the battery 10 having the lowest voltage value is activated, the complementary current in the group is supplied by the complementary current flowing from the constant current source 20 connected to the corresponding battery 10 via the switch 60 to the load. The discharge current of the battery 10 itself is reduced as compared with other batteries 10 that are not, and the voltage difference is eliminated. When the voltage difference becomes 15 mV or less, the constant current source 20 is stopped, and the constant current source 20 corresponding to the battery 10 having the next lowest voltage value is sequentially started in each group, so that the starting voltage is obtained. Give hysteresis to it. Such a configuration prevents frequent switching as in the case of charging.

As described above, according to the cell balance correction apparatus of the present embodiment, the constant current source 20 corresponds to the groups 1 to N including the plurality of batteries 10 among all the batteries 10 constituting the series battery 100. One supplemental current that complements the charge / discharge current of one battery 10 among the plurality of batteries 10 constituting the group is supplied via one switch 60 that is provided and controlled to be switched by the voltage monitoring unit 40.
Therefore, the effect that the cell balance of the battery voltage for each group of series batteries 100 can be corrected is obtained. Moreover, since the number of circuits of the constant current source 20 for controlling the entire series battery can be reduced, an effect that the manufacturing cost can be significantly reduced is obtained.

<Third Embodiment>
Hereinafter, a third embodiment of the cell balance correction apparatus of the present invention will be described with reference to the drawings. FIG. 5 is a configuration diagram of the cell balance correction apparatus of the present embodiment. The cell balance correction apparatus of this embodiment is different from the second embodiment in that a current source 21 having a variable current value is provided in place of the constant current source 20, and a current for measuring a charge / discharge current flowing through each group. The sensor 70 is provided, and a voltage / current monitoring unit 41 for monitoring the voltage / current is provided in place of the voltage monitoring unit 40. Hereinafter, the cell balance correction apparatus according to the present embodiment will not be described for points that are common to the first and second embodiments, and only different points will be described.
The current source 21 is activated by receiving an activation signal from the voltage / current monitoring unit 41, and a current corresponding to the voltage difference between the battery having the highest voltage value from the voltage / current monitoring unit 41 and the battery that activates the constant current source. A command is input to supply a complementary current to the battery 10.
For example, if a current command of 25% to 100% of the current source output is input at a voltage difference of 25 mV to 100 mV, and the voltage difference exceeds 100 mV, then a fixed output of 100% is set and the supplementary current to be supplied beyond this is supplied Do not increase.
The current source 21 inputs a current command corresponding to the charge / discharge current measured by the current sensor 70 when the discharge current supplied to the load is smaller than the complementary current corresponding to the voltage difference during discharge. The supplementary current 10 is supplied to the battery. For example, when the command value is set to about 10% of the charge / discharge current, the current source 21 outputs a complementary current of about 10% of the charge / discharge current to the battery 10.
When the voltage difference between the battery 10 having the highest voltage value and the battery 10 that activates the constant current source is larger than the threshold value, the voltage / current monitoring unit 41 shows a current value lower than the current command corresponding to the voltage difference. The command is output to the activated current source 21. Further, the voltage / current monitoring unit 41 inputs the charge / discharge current value measured by the current sensor 70 and outputs the current command according to the voltage difference and the charge / discharge current value described above to the activated current source 21. .
The current sensor 70 is provided for each group (FIG. 5) or in common for all groups, and measures the charge / discharge current of the series battery 100.

Next, the operation of the cell balance correction apparatus of this embodiment will be described.
First, at the time of charging, the series battery 100 is connected to a charger, and charging current is supplied to all the batteries 10. At this time, in each of the groups 1 to N, the voltage value measured by the voltage / current monitoring unit 41 of each group from all the voltage sensors 30 in the group and the current sensor 70 prepared for each group or common to all groups, and The charge / discharge current value is always output, and the voltage / current monitoring unit 41 first compares each voltage value input. Then, the voltage / current monitoring unit 41 selects, from each group, a battery 10 whose voltage is lower by 25 mV (millivolt) than the battery 10 having the highest voltage among the input voltage values.
If there is one battery 10 in each group whose voltage is 25 mV (millivolt) or more lower than the highest voltage battery 10, the voltage / current monitoring unit 41 activates the current signal 21 corresponding to this battery and a switch 60 switching signals are output. On the other hand, when there are a plurality of batteries 10 in each group whose voltage is 25 mV (millivolt) or more lower than that of the highest voltage battery 10, the voltage / current monitoring unit 41 is all applicable in the configuration in which the current source 21 is arranged for each battery. In order from the battery 10 or the lowest voltage, start signals for starting the current sources 21 corresponding to the limited number of batteries 10 are output. In the configuration in which one current source 21 is installed for each group, an activation signal for activating the current source 21 corresponding to the battery 10 having the lowest voltage value in each group is sequentially output. Simultaneously with the activation signal output of the current source, the voltage / current monitoring unit 41 outputs a current command corresponding to the voltage difference between the battery 10 having the highest voltage value and the battery 10 that activates the constant current source, and a switch 60 switching signal. To do.

When the current source 21 corresponding to the battery 10 is activated in each group, the corresponding battery 10 includes a battery having the highest voltage value from the current source 21 via the switch 60 in addition to the charging current supplied from the charger. A complementary current corresponding to the voltage difference between the battery 10 and the battery 10 is supplied. Thereby, charge is accelerated compared with the other battery 10 to which the complementary current in the group is not supplied, and the voltage difference is gradually eliminated.
However, in the case where the charging / discharging current is lower than the complementary current corresponding to the voltage difference between the battery 10 having the highest voltage value and the battery 10, the voltage / current monitoring unit 41 has a current corresponding to the charging / discharging current. The command is output to the current source 21.
For example, when a current command at a constant ratio is input to the charge / discharge current, the current source 21 sets the charge / discharge current smaller than the complementary current corresponding to the voltage difference between the battery 10 having the highest voltage value and the battery 10. On the other hand, a complementary current of a certain ratio is supplied to the battery 10 via the switch 60. Thereby, charge is accelerated compared with the other battery 10 to which the complementary current in the group is not supplied, and the voltage difference is gradually eliminated.

On the other hand, at the time of discharging, series battery 100 is connected to a load and supplies a discharging current. Similarly, in each of the groups 1 to N, the voltage / current monitoring unit 41 of each group is measured from all voltage sensors 30 in the group and one current sensor 70 prepared for each group or common to all groups. The voltage value and the charge / discharge current value are always output, and the voltage / current monitoring unit 41 first compares the respective voltage values input. Then, the voltage / current monitoring unit 41 selects, from each group, a battery 10 whose voltage is lower by 25 mV (millivolt) than the battery 10 having the highest voltage among the input voltage values.
If there is one battery 10 in each group whose voltage is 25 mV (millivolt) or more lower than that of the highest voltage battery 10, the voltage / current monitoring unit 41 activates the current source 21 corresponding to this battery, and The current command according to the voltage difference between the battery 10 having the highest voltage value and the battery 10 having the lowest voltage value, and the switching signal of the switch 60 are output. On the other hand, when there are a plurality of batteries 10 in each group whose voltage is 25 mV (millivolt) or more lower than that of the highest voltage battery 10, the voltage / current monitoring unit 41 is all applicable in the configuration in which the current source 21 is arranged for each battery. In the configuration in which the activation signal for activating the current sources 21 corresponding to the batteries 10 corresponding to the number of activations sequentially limited from the battery 10 or the lowest voltage is output, while one current source 21 is installed for each group. The activation signal for activating the current source 21 corresponding to the battery 10 having the lowest voltage value in sequence in each group is output.
Simultaneously with the activation signal output of the current source 21, the voltage / current monitoring unit 41 switches the switch 60 and the current command according to the voltage difference between the battery 10 having the highest voltage value and the battery 10 that activates the constant current source. Output a signal.

When the current source 21 corresponding to the battery 10 is activated in each group, a complementary current corresponding to the voltage difference between the battery 10 having the highest voltage value and the battery 10 flows to the load via the switch 60, so that Compared with other batteries 10 to which no supplemental current is supplied, the discharge current of the battery 10 itself decreases, and the voltage difference is eliminated.
However, in the case where the charge / discharge current is less than the complementary current corresponding to the voltage difference between the battery 10 having the highest voltage value and the battery 10, the voltage / current monitoring unit 41 determines the current command according to the charge / discharge current. Is output to the current source 21.
For example, when a current command at a constant ratio is input to the charge / discharge current, the current source 21 sets the charge / discharge current smaller than the complementary current corresponding to the voltage difference between the battery 10 having the highest voltage value and the battery 10. On the other hand, a certain amount of complementary current is supplied to the load via the switch 60. As a result, the discharge current of the battery 10 itself is reduced as compared with other batteries 10 to which no complementary current is supplied in the group, and the voltage difference is gradually eliminated.

  As described above, according to the cell balance correction apparatus of the present embodiment, the voltage / current monitoring unit 41 determines that the voltage difference when the voltage difference between the battery 10 having the highest voltage value and the battery 10 is larger than the threshold value. A current command indicating a current value lower than the current command corresponding to is output to the activated current source 21. With this configuration, a large current does not flow through the battery 10 even when the voltage difference is large. Therefore, an effect of preventing a decrease in charge / discharge efficiency due to a large current flowing can be obtained.

In addition, according to the cell balance correction apparatus of the present embodiment, a plurality of current sensors 70 for measuring charge / discharge currents of the plurality of batteries 10 constituting the series battery 100 are further provided, and the voltage / current monitoring unit 41 includes the current sensor. The charge / discharge current value measured by 70 is input, and a current command corresponding to the voltage difference and the charge / discharge current value is output to the activated constant current source.
Therefore, since a low complementary current corresponding to a low load can be supplied during discharge, an effect of efficiently equalizing the voltage of the series battery 100 can be obtained even when the load is low.

<Fourth embodiment>
Hereinafter, a fourth embodiment of the cell balance correction apparatus of the present invention will be described with reference to the drawings. FIG. 6 is a configuration diagram of the cell balance correction apparatus of the present embodiment. The difference between the cell balance correction apparatus of this embodiment and the first embodiment is that the current source 21 is supplied with a drive current from a predetermined external power supply apparatus 200 instead of the series battery 100. Hereinafter, the cell balance correction apparatus according to the present embodiment will not be described for points that are common to the first and second embodiments, and only different points will be described.
As shown in FIG. 6, an external power supply device 200 of a commercial system is connected via a bidirectional inverter 300 in the forward direction with respect to the discharge currents flowing through the groups 1 to N. The external power supply apparatus 200 is connected to the current source 21 of each group via the AC / DC converter 400 and supplies a drive current.
Therefore, an effect of reducing the power supply load of the series battery 100 can be obtained as compared with the case where the series battery 100 is used as a drive power supply source.

  In the above embodiment, the specific value of the complementary current is not particularly limited. For example, the charge / discharge current may be changed by 0.1 A (ampere) or 1 ampere according to the voltage value. Conceivable. For example, if the charging / discharging current is 10 A, it is assumed that a supplementary current of 1 A is supplied at an output of 100%, and a supplementary current of 0.25 A is supplied at an output of 25%.

The cell balance correction apparatus described above has a computer system inside.
A series of processes related to the cell balance correction process described above is stored in a computer-readable recording medium in the form of a program, and the above process is performed by the computer reading and executing this program.
That is, each processing means and processing unit in the cell balance correction device is performed by a central processing unit such as a CPU reading the above program into a main storage device such as a ROM or RAM and executing information processing / calculation processing. Is realized.
Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

In the first to fourth embodiments, an AC / DC converter may be used instead of the insulated DC / DC converter 50.
Further, a transformer may be used instead of the AC / DC converter 400.

The lineblock diagram of the cell balance amendment device of a 1st embodiment. The block diagram of the constant current source 20. FIG. FIG. 6 is another configuration diagram of the constant current source 20. The block diagram of the cell balance correction apparatus of 2nd Embodiment. The block diagram of the cell balance correction apparatus of 3rd Embodiment. The block diagram of the cell balance correction apparatus of 4th Embodiment. The block diagram of the conventional charging / discharging control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Battery 20 ... Constant current source 21 ... Current source 30 ... Voltage sensor 40 ... Voltage monitoring part 41 ... Voltage / current monitoring part 50 ... Insulation type DC / DC converter 60 ... Switch 70 ... Current sensor 100 ... Series battery 200 ... External Power supply 300 ... Bidirectional inverter 400 ... AC / DC converter

Claims (11)

A constant current source for supplying a complementary current that complements the charging / discharging current of a plurality of batteries constituting the series battery;
A plurality of voltage sensors for measuring voltage values of the plurality of batteries;
Voltage monitoring means for inputting a voltage value of each of the plurality of batteries from the plurality of voltage sensors, comparing the voltage values of the plurality of batteries, and starting the constant current source. Cell balance correction device. The constant current source is provided corresponding to one battery constituting the series battery,
The voltage monitoring means inputs the voltage value of each of the plurality of batteries from the plurality of voltage sensors, compares the voltage value of each of the plurality of batteries, and has a voltage value lower than a maximum voltage battery by a set value or more. The cell balance correction apparatus according to claim 1, wherein a constant current source corresponding to is activated. The constant current source is provided in correspondence with a group consisting of a plurality of batteries among all the batteries constituting the series battery, and the group is connected via a switching means that is controlled by the voltage monitoring means. Supplying a complementary current that complements the charge / discharge current of one battery among the plurality of batteries constituting the battery,
The voltage monitoring means inputs the voltage value of each of the plurality of batteries constituting the group from the plurality of voltage sensors, compares the voltage value of each of the plurality of batteries, and sets the voltage value from the highest voltage battery. 2. The cell balance correction device according to claim 1, wherein a constant current source corresponding to a battery having the lowest voltage value among the batteries having a value lower than the value is started. The voltage monitoring means further outputs a current command according to a voltage difference between a battery having the highest voltage value and a battery that activates the constant current source to the activated constant current source. The cell balance correction apparatus according to claim 3. When the voltage difference between the battery having the highest voltage value and the battery that activates the constant current source is greater than a threshold value, the voltage monitoring means outputs a current command indicating a current value lower than a current command corresponding to the voltage difference. The cell balance correction apparatus according to claim 4, wherein the cell balance correction apparatus outputs to the activated constant current source. One or more current sensors for measuring charge / discharge currents of a plurality of batteries constituting the series battery are further provided,
The voltage monitoring means inputs the charge / discharge current value measured by the current sensor, and outputs a current command according to the voltage difference and the charge / discharge current value to the activated constant current source. The cell balance correction apparatus according to claim 4 or 5. The cell constant correction apparatus according to any one of claims 1 to 6, wherein the constant current source is supplied with a drive current from the series battery. The cell balance correction apparatus according to any one of claims 1 to 6, wherein the constant current source is supplied with a drive current from a predetermined external power supply device.   A secondary battery comprising the cell balance correction device according to any one of claims 1 to 8. A plurality of voltage sensors measure the voltage value of each of the plurality of batteries constituting the series battery,
A constant current that inputs a voltage value of each of the measured plurality of batteries, compares a voltage value of each of the plurality of batteries, and supplies a complementary current that complements charge / discharge currents of the plurality of batteries constituting the series battery. A cell balance correction method characterized by starting a source. A process of inputting each voltage value from a plurality of voltage sensors provided in each of a plurality of batteries constituting the series battery;
And comparing the input voltage values of the plurality of batteries to start a constant current source that supplies a complementary current that complements the charge / discharge currents of the plurality of batteries constituting the series battery. Cell balance correction program.

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