JP2003087987A - Charging and discharging circuit for group of series- connected batteries - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging and discharging circuit for a group of series- connected batteries which enables exclusion of a deteriorated battery or equalization of voltages without interrupting charging and discharging operation by simple configuration. SOLUTION: This circuit is composed of a group of battery units which are obtained by connecting a plurality of series single elements in series. Each of the elements is formed by connecting a battery Bn, a first switching assembly composed of a first diode Dn1 arranged in the forward direction to a charging current Ir and a first switch Sn1 connected in parallel to the first diode, and a second switching assembly each of which is composed of a second diode Dn2 arranged in the reverse direction to the charging current and a second switch Sn2 connected in parallel to the second diode. Further, the element is connected in parallel to one of series single elements, and a control unit which turns off the first switch S11 of a first series single element, turns on the second switch S12 of a second switching assembly after that connected in parallel to the first series single element, and by-passes the battery B1 of the first series single element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging / discharging circuit for a group of batteries connected in series, and more particularly to a load leveling device used as a backup power source for factories, hospitals, etc. or for storing nighttime electric power and discharging it during the daytime. Applied to lithium secondary batteries installed in electric vehicles.

[0002]

2. Description of the Related Art FIG. 14 shows a battery group in which a large number of batteries are connected in series. Hereinafter, the case where each of the batteries is a lithium battery will be described as an example.

Some lithium batteries currently under development have an electromotive force of about 4 V in a single cell. This lithium battery is often used by being connected in series, and for example, 4 to 40 lithium batteries may be connected in series.

When lithium batteries are connected in series and used, the difference in characteristics of the lithium batteries poses a problem. That is, when charging and discharging are repeated, the voltage of each battery varies due to the difference in the characteristics of each battery. When the charging / discharging operation is repeated, even if the charging / discharging operation time is the same, the charging voltage and the discharging voltage of each battery differ. If a lithium battery is overcharged, it may lead to an accident, and if it is overdischarged, the battery capacity will be exhausted. For these reasons, strict protection and management are required for overcharge and overdischarge.

When variations occur in the battery voltage of lithium batteries connected in series in a single line, charging must be completed in accordance with the battery that reaches the charge termination voltage first, so other Since the battery cannot be fully charged and the discharge has to be completed in time for the battery that reaches the discharge end voltage at the very beginning, the other batteries cannot be completely discharged. For this reason, it is not possible to sufficiently charge or discharge the entire battery group connected in series.

As a method of suppressing this variation, FIG.
There is an example using a Zener diode as shown in No. 5 (see Japanese Patent Laid-Open No. 11-332115). The technique described in this publication focuses on preventing the charging voltage from becoming excessive. However, Zener diodes are not suitable for high currents. The Zener diode is used at about 1 to 3 A and cannot be used at a level exceeding 4 A.

Lithium batteries connected in series are, for example,
It is used for power load leveling, which stores night-time power and discharges it during the day. In this type of application, it is premised that a current of 10 to 20 A can be handled. Therefore, the Zener diode (general-purpose product) is not suitable for the above application.

Therefore, as shown in FIG. 16, a circuit for bypassing the current has been studied. Regarding battery B1, normally switch S111 is turned on and switch S112 is turned off.
Set to F, and switch S111 is turned off during bypass
And the switch S112 is turned on.

According to this circuit configuration, the switch S11
If the capacities of 1, S112, ..., S1n1, S1n2 are increased, it can be applied to a large current. However, when switching the switch, for example, when the battery B1 is bypassed, the switch S111 is turned off and then the switch S112 is turned on.
So that both switches S111, S112
It was necessary to provide a period in which the switch is OFF (when both switches S111 and S112 are ON, the battery B1 is short-circuited).

However, during a period in which both the switches S111 and S112 are off, there is no route for current to flow. Therefore, from the moment the switch S111, which was on until then, is turned off, an excessive surge voltage is applied to the part of the switch S111. Could occur. In this case, depending on the situation, it has been a factor that damages the battery.

As a preventive measure for this, at the time of charging, both the switches S111 and S112 are off (for example, 1
It is conceivable to prevent the generation of surge voltage by stopping the supply of the charging current at 00 μsec).

However, in order to prevent the generation of surge voltage as in the charging, the switch S11 is in discharging.
In the period in which both S1 and S112 are OFF, if the discharge current is not passed, the current cannot be taken during that period. Depending on the conditions on the load side, it may be essential to take out the current at all times, and in that case, the situation in which the current is not output should be avoided even temporarily.

As another preventive measure, it is possible to prevent the generation of surge voltage by providing a surge absorbing circuit (eg, snubber circuit). However, since the surge absorbing circuit is provided, the loss becomes large, and the capacity of the battery cannot be maximized during charging and discharging. Therefore, it is desirable to avoid the use of surge absorbing circuits.

[0014]

DISCLOSURE OF THE INVENTION An object of the present invention is to charge and discharge a series connected battery group capable of excluding deteriorated batteries or equalizing voltages without interrupting charge and discharge operations with a simple structure. To provide a circuit.

Another object of the present invention is to provide a charging / discharging circuit for a battery group connected in series, which has a simple structure and can eliminate deteriorated batteries or equalize voltages without interrupting charging / discharging operation. Especially.

[0016]

[Means for Solving the Problem] [Means for Solving the Problem] will be described below by using the numbers and symbols used in the [Embodiment of the Invention]. These numbers and signs are
Although added to clarify the correspondence between the description in [Claims] and the description in [Embodiment of the Invention], the technology of the invention described in [Claims] It should not be used to interpret the scope.

The charging / discharging circuit of the series-connected battery group of the present invention is the first circuit arranged in the forward direction with respect to the charging current (Ir).
Diode (Dn1) and the first diode (Dn1)
A first switching assembly composed of a first switch (Sn1) connected in parallel to the battery, and a battery group in which a plurality of series units connected to the battery (Bn) are connected in series,
A second device arranged in a direction opposite to the charging current (Ir)
Diode (Dn2) and the second diode (Dn2)
A second switch (Sn2) connected in parallel to the second switching assembly connected in parallel to the serial unit, and a battery voltage of the battery (B1) of the first serial unit during charging. Is equal to or higher than a predetermined value, the first switch (S11) of the first series simple substance is turned off.
F, and then the second switch (S12) of the second switching assembly connected in parallel to the first series unit is turned on to bypass the battery (B1) of the first series unit. And a control unit.

In the charging / discharging circuit for a series-connected battery group according to the present invention, the control unit is configured to control the first battery when the battery voltage of the second battery (B1) of the second battery is less than a predetermined value during discharging. Turning off the first switch (S11) of the second series unit, and then the second switch of the second switching assembly connected in parallel to the second series unit.
The switch (S12) is turned on to bypass the battery (B1) of the second series unit.

The charging / discharging circuit of the series-connected battery group according to the present invention is arranged so that the first body diode is formed in the forward direction with respect to the charging current (Ir).
S-FET (Sn1) and a battery (Bn) are connected to each other in series, and a second body diode is formed in the opposite direction to the charging current (Ir). The battery voltage of the second MOS-FET (Sn2) arranged as described above and connected in parallel to the serial unit and the battery voltage of the first serial unit battery (B1) during charging becomes equal to or higher than a predetermined value. Sometimes the first serial unit of the first
Turning off the MOS-FET (S11) of the second MOS, and then the second MOS connected in parallel to the first serial unit.
A control unit for turning on the FET (S12) and bypassing the battery (B1) of the first series unit.

In the charging / discharging circuit for a series-connected battery group according to the present invention, the control unit is configured to control the first battery when the battery voltage of the second battery (B1) of the second single battery unit becomes a predetermined value or less during discharging. The first MOS-FET (S
11) is turned off, and then the second MOS-FET (S12) connected in parallel to the second series unit is turned on to bypass the battery (B1) of the second series unit.

In the charging / discharging circuit of the series-connected battery group of the present invention, the operation reference when the control unit bypasses the battery (B1) is that the battery voltage of each battery (Bn) of the battery group is It is determined by whether or not it has reached a predetermined value.

In the charging / discharging circuit of the series-connected battery group of the present invention, the operation reference when the control unit bypasses the battery (B1) is the voltage of the two batteries (Bn) included in the battery group. Determined by the difference.

[0023]

DETAILED DESCRIPTION OF THE INVENTION One embodiment of the present invention will be described.

Referring to FIG. 1, a bypass circuit for a lithium secondary battery will be described as an embodiment of a charge / discharge circuit for a series-connected battery group according to the present invention.

When using batteries for power storage and electric vehicles, it is necessary to connect a plurality of batteries in series and use them as an assembled battery in order to increase the storage capacity of electricity. However, in reality, when batteries are connected in series, due to mixing of deteriorated batteries and variations in individual batteries,
Overcharge or over discharge of the battery occurs. In the present invention, the following methods are adopted to solve these problems.

As shown in FIG. 1, each switch S11, S
12, ... Adjacent to Sn1 and Sn2, a diode D11,
D12, ... Dn1, Dn2 are provided. The diodes D11, ... Dn1 are arranged in the forward direction with respect to the charging current. The diodes D12, ... Dn2 are arranged in the forward direction with respect to the discharge current.

In FIG. 1, the battery Bn is connected in series via a first switching assembly consisting of a diode Dn1 arranged in the forward direction with respect to the charging current and a switch Sn1 connected in parallel with it. It constitutes a battery group. The second switching assembly is connected in parallel to a series unit formed by connecting the first switching assembly and the battery Bn, and the diode Dn2 arranged in the opposite direction to the charging current is connected in parallel to the diode Dn2. It is composed of a connected switch Sn2.

First, the operation of bypassing the battery B1 during charging will be described.

First, at the normal time when the bypass is not performed, the switch S11 is ON, and the charging current flows into the battery B1 via the switch S11.

Next, when the battery voltage of the battery B1 exceeds a predetermined voltage, the switch S11 is turned off. When the switch S11 is turned off, the charging current flows into the battery B1 via the diode D11 (at this time,
Battery B1 continues to be charged).

Next, when the switch S12 is turned on, the switch S12 is turned on rather than the turn-on voltage of the diode D11.
Since the on-voltage of is smaller, the charging current is
2 and the battery B1 is bypassed. Also,
At this time, the diode D11 is reverse-biased by the battery B1, and the diode D11 is turned on.
FF is done.

Next, the operation of bypassing the battery B1 during discharge will be described.

First, the switch S11 is turned on during the normal time when the bypass is not performed, and the discharge current is the battery B1.
Flows from the + terminal side to the external load (not shown) via the switch S11.

Next, when the battery voltage of the battery B1 becomes lower than a predetermined voltage, the switch S11 is turned off. When the switch S11 is turned off, the discharge current flows to the external load via the diode D12. This allows
Even if the battery B1 is bypassed during discharging, the current path of the discharging current is secured.

The diode D12 has a high turn-on voltage, and the loss is large when a discharge current flows through the diode D12 for a long time. The discharge current is a large current (for example, 20
In the case of (A), it becomes a problem. Therefore, the switch S1
2 is turned on, and the discharge current is passed through the switch S12. As a result, the loss is effectively suppressed as compared with the case of passing through the diode D12.

From the above operation, the current path between the battery B1 bypassing at the time of charging and discharging is always secured, and the continuity of the current is maintained. Therefore, the surge absorbing circuit is not necessary and it is not necessary to stop the supply of the charging current.

FIG. 2 shows a concrete example. 2, members having the same functions as those in FIG. 1 are designated by the same reference numerals.

As shown in FIG. 2, the switch unit is a MOS-
It consists of FET. MOS-FET has a structure that
Since the diode part (this is called a body diode) is formed from the source to the drain, the circuit configuration is simplified by using it. The body diode is MO
It has the same current capacity as the S-FET.

The MOS-FETs S12 and Sn2 function as a bypass switch. Also, MOS-FET
When S11, S12, ... Sn1 and Sn2 are turned on, the current may flow in either the direction from the drain to the source or the direction from the source to the drain, so that it can function as a bidirectional switch. In FIG. 2, the MOS-FET is provided in one stage, but in the case of a large current, the MOS-FET can be provided in parallel in multiple stages.

Next, the operation of this embodiment will be described.

First, the operation of bypassing the battery B1 during charging will be described.

First, at the normal time when bypass is not performed, M
A bias voltage is applied to the gate of the OS-FET S11, the MOS-FET S11 is turned on, and the charging current flows into the battery B1 via the MOS-FET S11.

Next, when the battery voltage of the battery B1 exceeds a predetermined voltage (for example, 4, 2V), the MOS-F
Reverse bias voltage is applied to the gate of ET S11, and M
Turn off the OS-FET S11. MOS-FET
When S11 is turned off, the charging current is MOS-FE
It flows into the battery B1 via the body diode of T S11 (at this time, the battery B1 is continuously charged).

Next, when a predetermined voltage is applied to the gate of the MOS-FET S12 to turn on the MOS-FET S12, the on-voltage of the MOS-FET S12 is higher than the turn-on voltage of the body diode of the MOS-FET S11. Is small, the charging current is MOS-FET S1.
2 and the battery B1 is bypassed.

Next, the operation of bypassing the battery B1 during discharging will be described.

First, at the normal time when bypass is not performed, M
A bias voltage is applied to the gate of the OS-FET S11, the MOS-FET S11 is turned on, and the discharge current is from the + terminal side of the battery B1 to the MOS-FET S11.
Through an external load (not shown).

Next, when the battery voltage of the battery B1 becomes lower than a predetermined voltage (for example, 3 or 3 V), the MOS-F
Reverse bias voltage is applied to the gate of ET S11, and M
Turn off the OS-FET S11. MOS-FET
When S11 is turned off, the discharge current is MOS-FE.
It flows to the external load via the body diode of T S12. Thereby, even if the battery B1 is bypassed at the time of discharging, the current path of the discharging current is secured.

The body diode of the MOS-FET S12 has a high turn-on voltage, and the loss is large when the discharge current flows through the body diode for a long time. Therefore, a bias voltage is applied to the gate of the MOS-FET S12 to turn on the MOS-FET S12, and the MO-FET S12 is turned on.
A discharge current is passed through the S-FET S12. As a result, the loss of the discharge current is effectively suppressed as compared with the case of passing through the body diode of the MOS-FET S12.

From the above operation, the current path between the bypass of the battery B1 during charging and discharging is always ensured, and the continuity of current is maintained. Therefore, the surge absorbing circuit is not necessary and it is not necessary to stop the supply of the charging current.

Since the turn-on voltage of the body diode of the MOS-FET is generally high, a current flows through the body diode for a predetermined time or longer, causing heat generation or the like.
The MOS-FET may be damaged. In the present embodiment, the charging current flows through the body diode of the MOS-FET S11 for the duration of the MOS-FET S11.
Is turned off, the MOS-FET S12 is turned on.
It takes only a short time to switch to (for example, several hundred μsec). Similarly, the discharge current is MOS
-The time to flow through the body diode of FET S12 is
After the MOS-FETS11 is turned off, the MOS-
It is only a short time required for switching until the FET S12 is turned on (for example, several hundred μsec). Therefore, in this embodiment, there is no possibility that the MOS-FETs S11 and S12 are damaged by the current flowing through the body diode.

As described above, in the present embodiment, the current flows through the body diode in a short time, and the disadvantages associated with its use do not occur. Therefore, it is not necessary to use a diode (individual element) other than the body diode. .

In FIG. 2, the switch portion is on the positive terminal side of the battery, but there is no problem if the switch portion is on the negative terminal side of the battery as shown in FIG.

The bypass operation can be performed as follows. A description will be given separately for charging and discharging. There are two methods (1) and (2) for each charging / discharging time point.

[1] During charging (1) Each battery voltage is measured, and when the voltage reaches a predetermined value, the battery is bypassed. Bypass is released when discharging. (2) Each battery voltage is measured, two battery voltages are compared, and when the difference reaches a specified voltage, the battery with a high voltage is bypassed. The bypass of the bypassed battery is canceled when the battery voltage of the battery having the low battery voltage increases by the difference.

[2] During discharging (1) Each battery voltage is measured, and when the voltage reaches a predetermined value, the battery is bypassed. Bypass is canceled when charging. (2) Each battery voltage is measured, two battery voltages are compared, and when the difference reaches a specified voltage, the battery with a low voltage is bypassed. When the battery voltage of the battery having a high battery voltage drops by the difference, the bypass of the bypassed battery is released.

Next, with reference to FIGS. 4 and 5, the above [1] (1) will be specifically described. here,
The battery to be bypassed will be described as being removed as a deteriorated battery. However, even if the battery should be bypassed,
It goes without saying that it may be used as it is without being removed as a deteriorated battery.

FIG. 4 is an operation flow diagram at the time of charging when four batteries are temporarily used, and FIG. 5 is a block diagram of a depleted battery removing circuit at the time of charging.

In FIG. 5, the initial state during charging is the first
Switching assembly MOS-FET Sn1
Is turned on, and the MOS-FET Sn2 of the switch Sn2 of the second switching assembly is turned off.

At the time of charging from the charging device, the MOS-FET Sn1 of the first switching assembly is turned on.
The charging current is passed through the MOS-FET Sn1 to monitor the voltage of each battery Bn (S
1). As a result of the monitoring, when a deteriorated battery showing an abnormal voltage increase is detected (S2), the MOS-FET Sn1 of its first switching assembly is turned off, and then the switch of its second switching assembly is switched. When the MOS-FET Sn2 of Sn2 is turned on (S3) and the charging current is bypassed, the above deteriorated battery is excluded without stopping the system, and then the deteriorated battery is replaced with a new battery and all the batteries have the same voltage. The MOS-FET Sn2 of its second switching assembly is turned off and then the MOS-FET Sn1 of its first switching assembly is turned on (S4) to restore the normal state.

Next, with reference to FIGS. 6 and 7, the above (2) (1) will be described in detail. here,
The battery to be bypassed will be described as being removed as a deteriorated battery. However, even if the battery should be bypassed,
It goes without saying that it may be used as it is without being removed as a deteriorated battery.

FIG. 6 is an operation flow diagram (removal circuit) at the time of discharging when four batteries are used, and FIG. 7 is a block diagram of a circuit for removing a deteriorated battery at the time of discharging.

In FIG. 7, the initial state at the time of discharge is the first
Switching assembly MOS-FET Sn1
Is turned on, and the MOS-FET Sn2 of the switch Sn2 of the second switching assembly is turned off.

At the time of discharging to the load, the MOS-FET Sn1 of the first switching assembly is turned on, and the discharge current is passed through the MOS-FET Sn1 to monitor the voltage of each battery Bn (S5). . As a result of the monitoring, when a deteriorated battery showing an abnormal voltage drop is detected (S6), the MOS-FET Sn1 of its first switching assembly is turned off, and then the switch of its second switching assembly is switched. When the MOS-FET Sn2 of Sn2 is turned on (S7), the above deteriorated battery is excluded without stopping the system by bypassing the discharge current, and then the deteriorated battery is replaced with a new battery, and all the batteries have the same voltage. Turn off the MOS-FET Sn2 of its second switching assembly and then turn off the MOS-FET of its first switching assembly.
The FET Sn1 is turned on (S8) to restore the normal state.

Next, with reference to FIGS. 8 to 10, the above (1) (2) will be specifically described.

FIG. 8 is a voltage equalizing circuit diagram for bypassing the deteriorated battery at the time of charging when four batteries are used for equalizing the deteriorated battery, and FIG. 9 shows the relationship between time and voltage at that time. FIG. 10 is a graph diagram showing this, and FIG. 10 is a flow chart diagram showing the operation at that time.

In FIG. 8, batteries B connected in series
It is assumed that the battery B1 among 1, B2, B3, and B4 is a deteriorated battery having a higher voltage than the other batteries (see FIG. 9). The charging current of this circuit is Ir. Here, in order to balance the voltage V1 of the depleted battery with the voltage of the other batteries, M of its first switching assembly
Turn off the OS-FET Sn1 and then turn on the MO of the switch Sn2 of its second switching assembly.
The S-FET Sn2 is turned on (S9 in FIG. 10). At that time, the voltage V1 of the battery B1 drops to V1 ′ because the voltage drop due to the internal resistance becomes zero. Here, the voltage V1 at t1 is kept constant at V1 ′. After that, V at t2
When the value of 2 and V1 are equal to V1 (t1) at t1 (S10), turn off the MOS-FET Sn2 of its second switching assembly and then turn off its first switching assembly. MOS-FET
Sn1 is turned on (S11), and at that time, the voltage V1 is restored to this voltage. After t2, V1 is charged with the same voltage as V2, thus allowing balanced charging. This bypass operation repeats the bypass operation of the deteriorated battery many times even for a new voltage imbalance occurring after t2.
Equalize the voltage.

In the flowchart of FIG. 10, the average voltage Vav is obtained by removing the battery having the highest voltage, and the average voltage Vav is compared with the highest voltage to equalize the voltages. The method is not limited. For example,
The voltages of any two (adjacent) batteries are compared, and when the difference reaches a specified voltage, the high voltage battery is bypassed. The bypass of the bypassed battery can be canceled when the battery voltage of the battery having the low battery voltage rises by the difference.

Next, (2) of the above [2] will be specifically described with reference to FIGS. 11 to 13.

FIG. 11 is a voltage equalizing circuit diagram for bypassing a deteriorated battery during discharging, FIG. 12 is a graph showing the relationship between time and voltage at that time, and FIG. 13 shows the operation at that time. It is a flowchart figure shown.

In FIG. 11, B1, B2, B3, and B4 are batteries connected in series, and it is assumed that the battery B1 is a deteriorated battery having a lower voltage than other batteries (FIG. 12).
reference). The discharge current of this circuit is Io. Now, in order to balance the voltage V1 of the degraded battery with the voltage of the other batteries, turn off the MOS-FET S11 of its first switching assembly at t1, and then
Its second switching assembly MOS-FE
Turn on T Sn2 (S12 in FIG. 13). At that time,
The voltage V1 rises to V1 ″ because the battery B1 is opened. Here, the voltage V1 at t1 is kept constant at V1 ″. Then, when the value of V2 at time t2 and V1 become equal to V1 (t1) at time t1 (S13), the MOS-FET Sn of the second switching assembly of the same.
2 is turned off and then its first switching
Turn on the MOS-FET Sn1 of the assembly (S1
4) At that time, the voltage V1 is restored to this voltage. After t2, V1 is discharged at the same voltage as V2, which allows a balanced discharge. In this bypass operation, even if a new voltage imbalance occurs after t2, the bypass operation of the deteriorated battery is repeated many times to equalize the voltages.

In the flowchart of FIG. 13, the average voltage Vav is obtained by removing the battery having the lowest voltage, and the average voltage Vav is compared with the lowest voltage to equalize the voltages. The method is not limited. For example,
The voltages of any two (adjacent) batteries are compared, and when the difference reaches a specified voltage, the low voltage battery is bypassed. The bypass of the bypassed battery can be canceled when the battery voltage of the battery having the high battery voltage drops by the difference.

Instead of using the body diode of MOS-FET, an external diode can be used. When an external diode is used, a switch other than MOS-FET can be used.
As the switch, it is possible to use a relay (mechanical switch), an IGBT, a thyristor, a GTO, a power transistor, or the like, in addition to a semiconductor element such as a MOS-FET.

According to this embodiment, it is possible to provide a bypass circuit in which the batteries connected in series can be uniformly charged and discharged, and the continuity of current is ensured.

[0074]

According to the charging / discharging circuit for a series-connected battery group of the present invention, a deteriorated battery can be eliminated or the voltages can be equalized with a simple structure without interrupting the charging / discharging operation.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of an embodiment of a charging / discharging circuit of a series-connected battery group of the present invention.

FIG. 2 is a circuit diagram showing a specific example of an embodiment of a charging / discharging circuit for a series-connected battery group of the present invention.

FIG. 3 is a circuit diagram showing another specific example of the embodiment of the charging / discharging circuit of the series-connected battery group of the present invention.

FIG. 4 is a flowchart showing an operation at the time of charging in a specific example of one embodiment of the charging / discharging circuit of the series-connected battery group of the present invention.

FIG. 5 is a block diagram of a circuit for removing a deteriorated battery at the time of charging in a specific example of an embodiment of a charging / discharging circuit for a series-connected battery group of the present invention.

FIG. 6 is a flowchart showing an operation at the time of discharging in a specific example of an embodiment of the charging / discharging circuit of the series-connected battery group of the present invention.

FIG. 7 is a block diagram of a circuit for removing a deteriorated battery at the time of discharging in a specific example of an embodiment of a charging / discharging circuit for a series-connected battery group of the present invention.

FIG. 8 is a circuit diagram for explaining a voltage equalizing method for bypassing a deteriorated battery at the time of charging in a specific example of an embodiment of a charging / discharging circuit for a series-connected battery group of the present invention.

FIG. 9 shows time and battery voltage when a voltage equalizing method for bypassing a deteriorated battery at the time of charging is performed in a specific example of an embodiment of a charging / discharging circuit for a series-connected battery group of the present invention. It is a graph showing the relationship.

FIG. 10 is a flowchart showing an operation of a voltage equalizing method for bypassing a deteriorated battery at the time of charging in a specific example of an embodiment of a charging / discharging circuit for a series-connected battery group of the present invention.

FIG. 11 is a circuit diagram for explaining a voltage equalizing method for bypassing a deteriorated battery at the time of discharging in a specific example of an embodiment of a charging / discharging circuit of a series-connected battery group of the present invention.

FIG. 12 shows the time and the battery voltage when the voltage equalizing method for bypassing the deteriorated battery at the time of discharging is performed in the specific example of the embodiment of the charging / discharging circuit of the series-connected battery group of the present invention. It is a graph showing the relationship.

FIG. 13 is a flowchart showing an operation of a voltage equalizing method for bypassing a deteriorated battery at the time of discharging in a specific example of one embodiment of a charging / discharging circuit for a battery group of serial connection of the present invention.

FIG. 14 is a circuit diagram showing a configuration in which a large number of batteries are connected in series.

FIG. 15 is a circuit diagram showing a configuration of a conventional technique.

FIG. 16 is a circuit diagram showing a configuration of another conventional technique.

[Explanation of symbols] B1 battery B2 battery B3 battery B4 battery Bn battery D drain G Gate D11 diode D12 diode Dn1 diode Dn2 diode Ir charging current Io discharge current S source S11 MOS-FET (switch) S12 MOS-FET (switch) S21 MOS-FET (switch) S22 MOS-FET (switch) S31 MOS-FET (switch) S32 MOS-FET (switch) S41 MOS-FET (switch) S42 MOS-FET (switch) Sn1 MOS-FET (switch) Sn2 MOS-FET (switch) S111 switch S112 switch S1n1 switch S1n2 switch V1 battery voltage V2 battery voltage V3 battery voltage V4 battery voltage

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hidehiko Tajima             1-1 Satinoura Town, Nagasaki City, Nagasaki Prefecture Mitsubishi Heavy Industries             Nagasaki Shipyard Co., Ltd. (72) Inventor Katsuaki Kobayashi             3-5-1, 717-1, Fukahori-cho, Nagasaki-shi, Nagasaki             Hishi Heavy Industries Ltd. Nagasaki Research Center (72) Inventor Kosuke Harada             2-82 Watanabe Dori, Chuo-ku, Fukuoka City, Fukuoka Prefecture               Kyushu Electric Power Co., Inc. (72) Inventor Shunji Taniguchi             2-82 Watanabe Dori, Chuo-ku, Fukuoka City, Fukuoka Prefecture               Kyushu Electric Power Co., Inc. (72) Inventor Kazuyuki Adachi             2-82 Watanabe Dori, Chuo-ku, Fukuoka City, Fukuoka Prefecture               Kyushu Electric Power Co., Inc. (72) Inventor Goichi Ariyoshi             2-82 Watanabe Dori, Chuo-ku, Fukuoka City, Fukuoka Prefecture               Kyushu Electric Power Co., Inc. (72) Inventor Hiroyuki Shibata             2-82 Watanabe Dori, Chuo-ku, Fukuoka City, Fukuoka Prefecture               Kyushu Electric Power Co., Inc. F-term (reference) 5G003 AA01 BA03 CA14 CC02 CC04                       DA07 GA01                 5H030 AA03 AA04 AS03 AS08 BB01                       BB21 DD01 DD06 FF43 FF44

Claims (6)

[Claims] 1. A battery is connected to a first switching assembly comprising a first diode arranged in a forward direction with respect to a charging current and a first switch connected in parallel to the first diode. Consisting of a plurality of series-connected single cells connected in series, a second diode arranged in the opposite direction to the charging current, and a second switch connected in parallel to the second diode. A second switching assembly connected in parallel; and, when charging, when the battery voltage of the battery of the first series unit exceeds a predetermined value during charging, the first switching unit of the first series unit.
A controller for turning off the switch and then turning on the second switch of the second switching assembly connected in parallel to the first series unit to bypass the battery of the first series unit; A series charging / discharging circuit for a battery group. 2. The charging / discharging circuit for a series-connected battery group according to claim 1, wherein the control unit is configured to perform the discharging when the battery voltage of the battery of the second single unit in series becomes a predetermined value or less during discharging. Turning off the first switch of the second series unit and then turning on the second switch of the second switching assembly connected in parallel to the second series unit to turn on the second series unit. 2. A charging / discharging circuit for a series connected battery group that bypasses the battery. 3. A first M arranged so that its first body diode is formed in the forward direction with respect to the charging current.
A battery group in which a plurality of series single bodies each including an OS-FET and a battery are connected in series, and the series single body is arranged so that its second body diode is formed in a direction opposite to the charging current. A second MOS-FET connected in parallel to the first series unit, and a second MOS-FET connected to the first series unit when the battery voltage of the battery of the first series unit exceeds a predetermined value during charging.
And turning off the second MOS-FET connected in parallel to the first serial unit, and turning on the second MOS-FET of the first serial unit to bypass the battery of the first serial unit. Charge and discharge circuit for series connected batteries. 4. The charging / discharging circuit for a series-connected battery group according to claim 3, wherein the control unit is configured to perform the discharging when the battery voltage of the battery of the second serial unit becomes a predetermined value or less during discharging. The first MOS-FET of the second series single body is turned off, and then the second MOS-FET connected in parallel to the second series single body is turned on to turn on the second series single body. A series charging / discharging circuit that bypasses the batteries. 5. The charging / discharging circuit for a series-connected battery group according to claim 1, wherein the operation reference when the control unit bypasses the battery is that of each of the battery groups. A charging / discharging circuit for a series connected battery group that is determined by whether or not the battery voltage of the battery has reached a predetermined value. 6. The charging / discharging circuit for a series-connected battery group according to claim 1, wherein an operation standard when the control unit bypasses the battery is included in the battery group. A charging / discharging circuit for a series connected battery group determined by a voltage difference between the two batteries.