JP2000270483A - Charging condition controller of battery set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent not only overcharging but also overdischarging of a single battery while being small-sized and low-cost, avoiding wasteful consumption of charged energy. SOLUTION: A control circuit 4 shifts charges from a single battery 2A which is the highest in charged level in each group battery 1A to a single battery 2C which is the lowest in charged level via a capacitor 7A to equalize the charged condition of the single batteries 2A-2D within each group battery 1A, by operating a switch circuit 5A. At the same time, it shifts the charge from the single battery 2A the highest in charged level in the group battery 1A the highest in charged level to the single battery 2M which is the lowest in charged level in a group battery 1C which is the lowest in charged level at this time via capacitors 7A, 7B, and 7C to equalize the charged condition between the group batteries 1A and 1C by causing switching circuit 5A, 5B, 5C, 6AB, 6BC, and 6CA to operate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling the state of charge of a battery pack, and more particularly, to an apparatus for controlling the state of charge of each cell constituting a battery pack without causing overcharge or overdischarge due to variations in capacity.
The present invention relates to a charge state control device that can efficiently charge and discharge a battery pack.

[0002]

2. Description of the Related Art In recent years, the development of electric vehicles and the like has been energetically performed.
Attention is being paid to small, large-capacity lithium-ion batteries and the like. When such a secondary battery is used as a power source of an electric vehicle or the like, a desired voltage value is usually obtained by connecting a plurality of cells in series to form an assembled battery. But,
Lithium-ion batteries and the like tend to have variations in capacity due to the manufacturing history and subsequent use history, etc., and when charging or discharging the assembled battery as a single unit, small-capacity cells become overcharged or overdischarged, leading to performance degradation. There was a problem.

For example, in Japanese Patent Application Laid-Open No. 5-64377, the state of charge is detected from the terminal voltage of each cell, and when at least one of the cells is fully charged, charging of the assembled battery is stopped. There has been proposed a charging device that is stopped. However, in this charging device, the charging of the entire assembled battery is limited by the small-capacity unit cell. Therefore, there is a problem that the other large-capacity unit cell is not sufficiently charged, and the charging capacity is not fully utilized. .

Therefore, for example, in the charging device described in JP-A-8-213055, a shunt circuit is provided in parallel with each cell, and when one of the cells is fully charged, the shunt circuit is bypassed so as to bypass this. A charging current is supplied so that charging of other cells can be continued. However, in this charging device, there is a problem that the charging energy is wastefully consumed by the resistor provided in the shunt circuit for bypassing a part of the charging current.

On the other hand, Japanese Patent Application Laid-Open No. Hei 7-335266 discloses that a supplementary rechargeable battery is connected to each unit cell via a switching circuit, and when the unit cell is about to be overcharged, the unit cell is supplementarily charged. A charging device has been proposed in which a battery is connected to prevent overcharging. However, in this charging device, since the auxiliary rechargeable battery is provided for each unit cell, there is a problem that an increase in the size of the entire device and an increase in cost cannot be avoided.

[0006] When the discharge of the assembled battery proceeds, there is a possibility that the single cell having the smallest capacity may be over-discharged as described above.
There is no suggestion for a solution to this.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention is intended to solve the above-mentioned problems, and can avoid wasteful consumption of charging energy, and is small in size and low in cost. An object of the present invention is to provide an assembled battery charge state control device that prevents not only overcharge but also overdischarge and enables efficient charge and discharge of the assembled battery.

[0008]

According to the first aspect of the present invention, a plurality of single cells (2A to 2A) are provided.
D, 2E to 2H) and a plurality of group batteries (1A, 1A,
1B), and each group battery (1A, 1B) includes a plurality of unit cells (2A to 2D, 2E to 2E) connected in series.
H), auxiliary charge / discharge devices (7A, 7B), and each cell (2
A to 2H), a first state-of-charge detecting means (3A to 3H) for detecting the state of charge, and at least one unit cell including the unit cell having the highest charge level or the unit cell having the highest charge level Of the appropriate number of cells in the first series battery group (2
A, 2B and 2E, 2F), the first series battery group is connected in parallel to the auxiliary charger / discharger (7A, 7B), and then the unit cells (2C, 2C,
2G) or a smaller number of adjacent cells including the cells with the lowest charge level than the first series of cells as the second series of cells, and selecting the cells with the lowest charge level ( 2C, 2G) and first switching connection means (5A, 5B) for repeating a switching operation for connecting the second series battery group to the auxiliary charger / discharger (7A, 7B) in parallel. A second state-of-charge detecting means (4) for detecting the state of charge of the batteries (1A, 1B); a unit cell having the highest charge level in the group battery (1A) having the highest charge level; One or more suitable number of cells including high cells and adjacent thereto is selected as the third series battery group (2A, 2B), and the highest charge level or third series battery group is selected. The above highest charge level After connecting in parallel to the auxiliary discharge vessel loops battery (1A) (7A), the auxiliary discharge vessel of a low group battery the least charge level at this point (1B) (7
B) The group battery with the highest charge level (1A)
Of the group battery (1B) having the lowest charge level, or the cell having the lowest charge level at this time in the group battery (1B) having the lowest charge level. And a smaller number of adjacent cells than the third series battery group is selected as the fourth series battery group, and the cells (2E) to the fourth series battery group having the lowest charge level are selected as the fourth series battery group. Second switching connection means (5A, 5) that repeats the switching operation of connecting in parallel to the auxiliary charger / discharger (7B) of the group battery (1B) with the lowest charge level
B, 6AB).

In the first invention, when the first series battery group including the unit cell having the highest charge level in each group battery is connected to the auxiliary charger / discharger, the first series battery group is connected to the auxiliary battery charger. A current is supplied to the discharger, and the voltage of the cell having the highest charge level decreases. Thereafter, when a smaller number of the second series battery groups including the unit cells having the lowest charge level at this time and less than the first series battery group are connected to the auxiliary charger / discharger, the current of the auxiliary charger / discharger is reduced. The second series battery group is discharged and supplied, and the second series battery group is charged. When the charge level of the other cells becomes the highest, the same operation is performed between the new first series battery group including the other cells and the auxiliary charger / discharger, and the charge levels decrease one after another. At the same time, the second series battery group is charged from the auxiliary charger / discharger, the charge level of each unit cell is increased, and the charge state of the unit cells in the group cells is always uniformed. And
If the state of charge is not uniform among the group batteries, the third series battery group including the unit cells having the highest charge level in the group battery having the highest charge level is connected to the auxiliary charger / discharger, and the third series battery is connected. A current is supplied from the battery group to the auxiliary charge / discharge device, and the voltage of the unit cell having the highest charge level decreases. Subsequently, the auxiliary charger / discharger is connected to the auxiliary charger / discharger of the group battery having the lowest charge level to transfer the charge,
Then, in the group battery with the lowest charge level,
At this time, the fourth series battery group including the unit cell with the lowest charge level is connected to the auxiliary charger / discharger, and the current of the auxiliary charger / discharger is efficiently discharged and supplied to the fourth series battery group, 4
Are charged. When the charge level of the other group batteries becomes the highest, the same operation is performed between the new third series battery group and the auxiliary charger / discharger in the group battery, and the charge levels are reduced one after another. Then, charging is performed from the auxiliary charger / discharger to the fourth series battery group in the group battery having the lowest charge level to increase the charge level, and as a result, the state of charge between the group batteries is always equalized. According to the first aspect of the present invention, the charge states of the cells belonging to each group are equalized at the same time as the charge states of the group cells are balanced, so that the charge states can be quickly equalized. In addition, the entire capacity of the battery pack at the time of charging and discharging is efficiently used, and overcharging and overdischarging of the unit cells are also prevented.

In the second invention, a plurality of group batteries (1A, 1B) each composed of a plurality of unit cells (2A to 2J, 2E to 2H) and connected in series to each other to form a battery pack (CB) are provided. Equipped, each group battery (1A, 1
B) includes a plurality of unit cells (2A to 2J,
2E to 2H), auxiliary charge / discharge devices (7A, 7B), first charge state detecting means (3A to 3J) for detecting the charge state of each cell (2A to 2J), and the highest charge level. A single cell, or one or more suitable number of cells including the cell with the highest charge level and adjacent thereto is selected as a first series battery group (2A, 2B and 2E, 2F), and After one series battery group is connected in parallel to the auxiliary charger / discharger (7A, 7B), at this time, the cells (2C, 2G) having the lowest charge level or the cells having the lowest charge level are included. A smaller number of adjacent cells than the first series of cells are selected as the second series of cells, and the cells (2C, 2G) or the second series of cells with the lowest charge level are supplementarily charged. The switching operation of connecting the discharger (7A, 7B) in parallel is repeated. To the first switching connection means (5A, 5
B), and each group battery (1A, 1B)
Second state-of-charge detecting means (4) for detecting the state of charge of the battery
And a cell having the highest charge level in the group battery (1A) having a relatively high charge level among the adjacent group batteries (1A, 1B), or a cell including the cell having the highest charge level and being adjacent thereto. One or more suitable cells are selected as a third series battery group (2A, 2B),
After connecting the single battery with the highest charge level or the third series battery group in parallel to the auxiliary charger / discharger (7A) of the group battery (1A) with the relatively high charge level,
A cell connected to one group battery (1A) among the adjacent group batteries (1A) and one or more unit cells including and including the unit cell adjacent to another group battery (1B) is connected in a fifth series. The battery group (2I, 2J) is selected, and the unit cell (2I) having the lowest charge level among these, or a smaller number of adjacent cells than the third series battery group including the unit cell having the lowest charge level. Is selected as the fourth series battery group, and the unit cells (2I) having the lowest charge level through the fourth series battery group are supplementally charged with the group batteries (1A) having the relatively high charge level. The battery is connected in parallel to the discharger (7A), and then the unit cells or the fifth series battery group (2I, 2J) are connected to the auxiliary charger / discharger (7B) of the group battery (1B) having a relatively low charge level. Connect in parallel Further, after that, in the group battery (1B) having the relatively low charge level, the cell (2E) having the lowest charge level at this time or the cell (2E) having the lowest charge level is included in the fifth battery. A smaller number of adjacent unit cells than the series battery group (2I, 2J) are selected as the sixth series battery group, and the unit cells (2E) to the sixth series battery group having the lowest charge level are described above. Second switching connection means (5A, 5B) for repeating a switching operation of connecting the auxiliary battery (7B) of the group battery (1B) having a relatively low charge level in parallel to the auxiliary charging / discharging device (7B).

In the second invention, the charge is transferred from the first series battery group to the second series battery group by the same operation as in the first invention, and the state of charge of the unit cells in each group of batteries is changed. And the electric charge is transferred from the third series battery group to the sixth series battery group via the fourth and fifth series battery groups, so that the charging between the group batteries is performed. The state is made uniform and the first
The same effect as the invention can be obtained. In particular, in the second aspect of the present invention, since the charge transfer between the group batteries is not performed directly by the auxiliary charger / discharger, but is performed via the fourth and fifth series battery groups, all the switching connection means are FETs having a low required withstand voltage. (Effect transistor) switch, which has the effect of reducing the size and cost.

In the third invention, a plurality of cells (2A to 2D, 2I, 2J and 2E to 2H, 2I, 2J) are respectively provided.
Composed of at least one unit cell (2I, 2J)
And a plurality of group batteries (1A, 1B) connected in series with each other to form a battery pack (CB),
Each group battery (1A, 1B) has a plurality of unit cells (2A to 2D, 2I, 2J and 2E to 2H, 2) connected in series.
I, 2J), auxiliary charge / discharge devices (7A, 7B), charge state detection means (3A-3J) for detecting the charge state of each cell (2A-2J), a cell having the highest charge level, Alternatively, one or more appropriate number of cells including the cell having the highest charge level may be connected to the first series cell group (1
A, 1B and 2E, 2F), and after connecting the first series battery group to the auxiliary charger / discharger (7A, 7B) in parallel, the cells (2C, 2C,
2G) or a smaller number of adjacent unit cells including the unit cell with the lowest charge level than the first series cell group as the second series cell group, and selecting the unit cell with the lowest charge level Switching connection means (5A, 5B) for repeating a switching operation of connecting (2C, 2G) or the second series battery group to the auxiliary charger / discharger (7A, 7B) in parallel is provided.

In the third aspect of the present invention, when the first series battery group including the unit cell having the highest charge level in each group battery is connected to the auxiliary charger / discharger, the first series battery group is switched from the first series battery group to the auxiliary battery. A current is supplied to the discharger, and the voltage of the cell having the highest charge level decreases. Thereafter, when a smaller number of second series battery groups including the unit cells having the lowest charge level at this time are connected to the auxiliary charger / discharger, the charge of the auxiliary charger / discharger is reduced. The second series battery group is discharged and supplied, and the second series battery group is charged. When the charge level of the other cells becomes the highest, the same operation is performed between the new first series battery group including the other cells and the auxiliary charger / discharger, and the charge levels decrease one after another. At the same time, the second series battery group is charged from the auxiliary charger / discharger, the charge level of each unit cell is increased, and the charge state of the unit cells in the group cells is always uniformed. At this time, in the present invention, since one or more single cells are shared between adjacent group batteries, the exchange of charge by charge and discharge between the single cells in each of the above-described group batteries is also performed on adjacent group batteries. As a result, the state of charge between the group batteries is also made uniform at the same time.

The reference numerals in parentheses indicate the correspondence with the specific means described in the embodiments described later.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows the overall configuration of a charging state control device. The charge state control device includes a plurality (three in this embodiment) of group batteries 1A, 1B, 1
C in series, and each group battery 1A, 1B, 1C has a plurality (four in this embodiment) of unit cells 2A, 2B, 2C, 2D and 2E such as lithium ion batteries. 2F, 2G, 2H and 2M, 2N, 2O, 2P are connected in series. A charge / discharge line L extends from the battery pack CB, and when charging the battery pack CB, a current is supplied to the charge / discharge line L from a charging power supply (not shown).
Is discharged, a current is supplied from the charge / discharge line L to a load (not shown).

A voltmeter 3A, 3B, 3C,..., 3H, 3M-3P is connected in parallel to each of the cells 2A-2H, 2M-2P, and a voltage signal from each voltmeter 3A-3P Is being entered. In a lithium ion battery or the like, the charge state of the battery is substantially proportional to the battery voltage, so that the control circuit 4 can easily and accurately know the charge state of each of the cells 2A to 2P by the voltage signal. Of course, it is also possible to know the state of charge by means other than the voltmeter. Capacitors 7A to 7C are provided as auxiliary charge / discharge devices corresponding to the respective group batteries 1A to 1C.
Switching circuits 5A to 5C as switching connection means are interposed between C and each group battery 1A to 1C. Each of the switching circuits 5A to 5C is switched and operated by a signal from the control circuit 4 as described later, and selects a single cell or a series battery group consisting of an appropriate number of cells adjacent to each other and supplies it to the capacitors 7A to 7C. Switch connection.
Note that the capacitance of the capacitor is about several thousand to 10,000 μF.
Switching circuits 6AB, 6BC, and 6CA as switching connection means are interposed between the capacitors 7A to 7C.
Switching operation is performed by a signal from the control circuit 4 as described later.

The switching circuits 5A to 5C are provided with switches 51A to 5C connecting the positive electrodes of the cells 2A to 2D, 2E to 2H and 2M to 2P and the positive electrodes of the capacitors 7A, 7B and 7C.
1D, 51E to 51H, 51M to 51P, and each cell 2
Switches 52A-52 connecting negative electrodes of A-2D, 2E-2H, 2M-2P and negative electrodes of capacitors 7A, 7B, 7C.
D, 52E to 52H and 52M to 52P. The switching circuits 6AB to 6CA are switches 61A connecting the positive electrodes of the capacitors 7A to 7C, respectively.
61C and switches 62A to 62C connecting the negative electrodes of the capacitors 7A to 7C. These switches 51A to 51P, 52A to 52P, 61A to 61
As C and 62A to 62C, for example, an FET switch can be suitably used.

The operation of the charging / discharging device having such a configuration will be described below with reference to the flowcharts of FIGS. In FIG.
In step 100, the state of charge of the cells in each of the group batteries 1A to 1C is equalized. This solves the non-uniform charge state among the cells 2A to 2D, 2E to 2H, and 2M to 2P that constitute the group batteries 1A to 1C for each of the group batteries 1A to 1C. 3 is shown.

In FIG. 3, each of the group batteries 1A to 1C
2A-2D, 2E-2H, 2M-2P
Out of the group batteries, the unit cell having the highest charge level and one or more suitable single cells adjacent thereto are selected as the first series battery group (step 101).
Are connected in parallel to the capacitors 7A to 7C by the switching circuits 5A to 5C, respectively (step 102). The charge level of each cell is, as described above, a voltmeter 3 connected in parallel to these cells 2A to 2P.
It can be known from the values of A to 3P. After a lapse of a predetermined time (step 103), in step 104, the cells 2A to 2A
D, 2E to 2H, and 2M to 2P, the unit cells having the lowest charge level in each group battery, or the number of adjacent cells including the unit cells having the lowest charge level and less than the first series battery group. The battery is selected as the second series battery group (step 104), and the unit cell or the second series battery group having the lowest charge level is connected in parallel to the capacitors 7A to 7C by the switching circuits 5A to 5C for a certain time. (Steps 105 and 106). Step 107
Then, it is confirmed whether or not the uniformity of the charged state of all the cells has been completed.

For example, in FIG. 1, it is assumed that the cell 2A has the highest charge level among the group batteries 1A, and the cell 2C has the lowest charge level at this time. The control circuit 4 selects the unit cell 2A and the unit cell 2B adjacent to the unit cell as a first series cell group, and makes the switches 51A and 52B conductive. As a result, current flows from the first series battery group 2A, 2B to the capacitor 7A, the voltage of the unit cells 2A, 2B decreases, and the capacitor 7A is charged. After the elapse of the predetermined time t1, the control circuit 4 selects the cell 2C having the lowest charge level and switches 51A and 52B.
, The switches 51C and 52C are turned on. As a result, current flows from the capacitor 7A to the cell 2C, and the cell 2C is charged. The capacitor 7A at this time
Is almost twice the voltage of the unit cell 2C, so that efficient and reliable charging is quickly performed. After a predetermined time t2 has elapsed, the switches 51C and 52C are turned off. The fixed times t1 and t2 correspond to the first series battery group 2A,
The time is set to a time sufficient for a uniform state between the cell 2B and the capacitor 7A or between the cell 2C and the capacitor 7A to stop the current from flowing. Therefore, it may be possible to detect that the current has actually stopped flowing and proceed to the next operation. The same operation is performed for the other group batteries 1B and 1C.

The above operation, that is, step 10 in FIG.
The operations of 1 to 107 are repeated at, for example, 5 Hz, and when the charge level of the other cell is the highest, the other cell and the cell adjacent thereto are selected as a new first series cell group, A similar operation is repeated between the new first series battery group and the unit cell having the lowest charge level at this time or the second series battery group including the same via the capacitor 7A, 7B or 7C. . By repeating such an operation, all the cells 2A to 2D, 2E to 2H, and 2M to 2P constituting each group battery 1A, 1B, 1C are overcharged during charging of the battery pack CB. In this state, the cells 2A to 2D, 2E to 2H, and 2M to 2P are charged to their full capacity and become fully charged. During the discharge of the assembled battery CB, all the cells 2A to 2D and 2E to 2E
The discharge levels (charge levels) of the H and 2M to 2P are made uniform without causing overdischarge, and the discharge is completed almost simultaneously. Therefore, the cells 2A to 2D, 2E to 2H, 2
Since overdischarge of M to 2P can be avoided, and no residual charge is generated in each unit cell at the end of the discharge operation, battery deterioration due to recharging while generating the residual charge can also be avoided. Note that it is better to check the state of charge of the cells 2A to 2P only when charging and discharging of the cells are suspended. The reason is that when the charge / discharge current is flowing, the terminal voltages of the cells 2A to 2P fluctuate, and the state of charge may not be accurately determined. The uniformity of the charge / discharge state in each of the group batteries does not need to be performed only at the time of charge / discharge of the assembled battery, but may be performed at all times.

Cell 2A in each group of batteries 1A-1C
2D, 2E to 2H, and 2M to 2P, the charging state is made uniform by the above-described procedure.
If the state of charge among the group batteries 1A to 1C becomes non-uniform at 00, the group batteries 1A to 1C described in detail below are used.
During this time, the state of charge is made uniform (step 300). The state of charge of each of the group batteries 1A to 1C is determined by the unit cells 2A to 2D, 2 constituting the group batteries 1A to 1C.
It can be known by adding the terminal voltages of E to 2H and 2M to 2P in the control circuit 4. Group battery 1A
FIG. 4 shows the procedure for equalizing the state of charge between 1C and 1C.

In FIG. 4, each of the group batteries 1A to 1C
Of the group batteries having the highest charge level, for example, the group battery 1A, and the cells 2A to 2A constituting the same.
Among D, the unit cell having the highest charge level and one or more suitable unit cells adjacent thereto are selected as the third series battery group (step 301), and this third series battery group is switched. The circuit 5A connects the capacitor 7A in parallel (step 302). After a lapse of a predetermined time (step 303), in step 304, the group battery 1A having the highest charge level and the group battery having the lowest charge level at this time, for example, the capacitor 7C of the group battery 1C are connected by the switching circuit 6CA ( Step 304), charging the capacitor 7C of the group battery 1C. After a lapse of a predetermined time (step 305), the cells having the lowest charge level or the cells having the lowest charge level among the cells 2M to 2P constituting the group battery 1C are higher than the third series cell group. A small number of adjacent cells are selected as the fourth series cell group (step 306), and the cell having the lowest charge level or the fourth cell group is selected.
Are connected in parallel to the capacitor 7C by the switching circuit 5C for a predetermined time (steps 307 and 3).
08). In step 309, it is checked whether or not the non-uniformity between the group batteries in question has been resolved. If the non-uniformity has been resolved, the process returns to step 100 in FIG.

For example, in FIG. 1, it is assumed that the charge level of the group battery 1A is the highest, and the cell 2A has the highest charge level in the group battery 1A. The control circuit 4 selects the unit cell 2A and the unit cell 2B adjacent to the unit cell as a third series cell group, and turns on the switches 51A and 52B. As a result, a current flows from the third series battery group 2A, 2B to the capacitor 7A, and the capacitor 7A is charged. After the elapse of the predetermined time t3, the control circuit 4 conducts the switches 61C and 62C of the switching circuit 6CA in place of the switches 51A and 52B to connect the capacitor 7C of the group battery 1C and the capacitor 7A,
The former is charged by the latter. In this state, after a lapse of a predetermined time t4, the control circuit 4 selects the cell 2M having the lowest charge level from the group batteries 1C, and switches 61C and 62C.
The switches 51M and 52M are turned on in place of C,
The cell 2M is connected to the capacitor 7C. This allows
A current flows from the capacitor 7C to the cell 2M, and the cell 2M is charged. At this time, the voltage of the capacitor 7C is almost twice the voltage of the cell 2M, so that efficient and reliable charging is quickly performed. After a predetermined time t5 has elapsed, the switches 51M and 52M are turned off. During the above-mentioned fixed times t3, t4, t5, a current flows when the third series battery groups 2A, 2B and the capacitor 7A, the capacitor 7A and the capacitor 7C, and the capacitor 7C and the unit cell 2M become uniform. Allow enough time for it to disappear. Therefore, it may be possible to detect that the current has actually stopped flowing and proceed to the next operation.

The above operation, that is, step 30 in FIG.
The operations of 1 to 309 are repeated at, for example, 5 Hz, and when the charge level of the other group batteries becomes the highest,
A similar equalizing operation is performed between the other group battery and the group battery having the lowest charge level at this time.
According to the present embodiment, the assembled battery is divided into a plurality of group batteries including a predetermined number of cells, and the state of charge among the cells is made uniform in each group battery simultaneously and in parallel. Accordingly, the state of charge of the unit cells can be quickly uniformed. Therefore, the capacity of the entire assembled battery can be efficiently used at the time of charging and discharging, and overcharging and overdischarging of the unit cells can be prevented. Further, each of the switches 51A to 51A of the switching circuits 5A, 5B, 5C
When using an FET switch as 52P, FE
Since only the voltage in each group of batteries is applied to the T switch and the voltage of the entire assembled battery is not applied, an inexpensive and small FET switch having a small withstand voltage can be used. In step 304 of FIG. 4, the switching circuits 6AB and 6BC may be sequentially operated instead of the switching circuit 6CA. In this case, the switching circuit 6CA is unnecessary.

(Second Embodiment) In this embodiment, in order to facilitate understanding, as shown in FIG. 5, only two of the three group batteries in the first embodiment are shown and described below. . In the present embodiment, the switching circuit between the group batteries 1A and 1B (such as 6AB in FIG. 1) is abolished, and the cells 2I and 2J belonging to the group battery 1A are newly provided at a position close to the adjacent group battery 1B. I have. The positive electrodes of the cells 2I and 2J are connected to the capacitors 7 through the switches 51I and 51J of the switching circuit 5A.
A is connected to the positive electrode of A and the switching circuit 5B
Are connected to the positive electrode of the capacitor 7B of the group battery 1B via the switches 51K and 51L. The negative electrodes of the cells 2I and 2J are connected to the negative electrode of the capacitor 7A via the switches 52I and 52J, and also connected to the negative electrode of the capacitor 7B of the group battery 1B via the switches 52K and 52L of the switching circuit 5B. ing.

Cell 2A in each group of batteries 1A, 1B
2J and 2E to 2H are made uniform by the procedure already described in the first embodiment by appropriately switching the switches 51A to 52J and 51J in the switching circuits 5A and 5B.
By operating E-52H, each group battery 1
The charge and discharge are repeated between the cells 7A and 7B and each unit cell or series battery group constituting the same for each of A and 1B, thereby achieving uniformity.

The procedure for equalizing between the group batteries 1A and 1B by the control circuit 4 when unevenness occurs between the group batteries 1A and 1B will be described below. It is assumed that the charge level of the group battery 1A is relatively high, and the cell 2A has the highest charge level in the group battery. The control circuit 4 selects the unit cell 2A and the unit cell 2B adjacent to the unit cell as a third series cell group, and turns on the switches 51A and 52B. As a result, a current flows from the third series battery group 2A, 2B to the capacitor 7A, and the capacitor 7A is charged. After a certain period of time, the cells 2I and 2J are selected as a fifth series battery group, and the charge levels of these cells 2I and 2J are compared. If the charge level of the cells 2I is lower, the control circuit 4 The cells 51 are charged by conducting the switches 51I and 52I in place of the switches 51A and 52B. After a certain time has passed in this state, the switch 51
The switches 51K and 52L are turned on in place of I and 52I, and the capacitor 7B is charged by the cells 2I and 2J as the fifth series battery group. Further, assuming that the charge level of the unit cell 2E is the lowest in the group battery 1B after a certain period of time has elapsed, the control circuit 4 switches the switches 51K and 52K.
The switches 51E and 52E are turned on in place of L to connect the capacitor 7B to the cell 2E. As a result, current flows from the capacitor 7B to the cell 2E,
E is charged. At this time, the voltage of the capacitor 7B is almost twice the voltage of the cell 2E, so that efficient and reliable charging is quickly performed. The switches 51E and 52E are turned off after a certain period of time.

In the present embodiment, the switches 6AB and 6BC for switching between the auxiliary charge / discharge devices of the group battery in the first embodiment are not required. Therefore, when FET switches are used as switches, all switches are used. Of the switching circuit can be reduced, and the cost and size of the switching circuit can be reduced.

In the present embodiment, a case will be described in which the fifth series battery group in a certain group of batteries is composed of two single cells, and the single cells in an adjacent group of batteries are charged via a capacitor. However, the fifth series battery group is constituted by three or more unit cells, and a smaller number of sixth series battery groups than the fifth series battery group in the adjacent group batteries are charged. Is also good. Instead of selecting the unit cell 2I, a smaller number of unit cells than the third series battery group including the unit cell are selected as the fourth series battery group, and the fifth series battery group is replaced with the fourth series battery group. And an appropriate number of unit cells including the series battery group. Further, it is needless to say that the fourth and fifth series battery groups may be provided in any adjacent group batteries.

(Third Embodiment) To facilitate understanding in this embodiment, only two of the three group batteries in the first embodiment will be described below.
In FIG. 6, the group battery 1A in the second embodiment
The cells 2I and 2J belonging only to the group battery 1B belong to the adjacent group battery 1B. Then, as described in the first embodiment, each of the group batteries 1A, 1B is switched by the switching circuits 5A, 5B via the capacitors 7A, 7B.
The electric charge is transferred between the unit cells or the series cell groups in each cell, whereby each cell 2A in each group cell 1A, 1B is transferred.
The charge states of A to 2D, 2I, 2J and 2I, 2J, 2E to 2H are made uniform. At this time, both group batteries 1A, 1B
Since the cells 2I and 2J are shared between the cells, the exchange of charge by charge / discharge between the series cells or the cells in each group cell 1A and 1B spreads to the adjacent group cells 1A and 1B, Thereby, the group battery 1
The charge state between A and 1B is made uniform at the same time. In this embodiment, only the unit cell 2J may be shared by both groups of batteries, or three or more unit cells may be shared by both groups of batteries.

In each of the above embodiments, it is possible to always charge only one unit cell to another unit cell without selecting a series cell group.

[0033]

As described above, according to the battery state control apparatus of the present invention, it is possible to avoid wasteful consumption of charging energy, and at the same time, it is small and low-cost, and only overcharges the unit cells. In addition, overdischarging can be prevented, and efficient charging and discharging of the assembled battery can be realized.

[Brief description of the drawings]

FIG. 1 is a main part circuit diagram of a state-of-charge control device, showing a first embodiment of the present invention.

FIG. 2 is a flowchart of a control circuit.

FIG. 3 is a flowchart of a control circuit.

FIG. 4 is a flowchart of a control circuit.

FIG. 5 is a main part circuit diagram of a state-of-charge control device, showing a second embodiment of the present invention.

FIG. 6 is a main part circuit diagram of a charge state control device showing a third embodiment of the present invention.

[Explanation of symbols]

1A, 1B ... group battery, 2A, 2B, 2C, 2D,
2E, 2F, 2G, 2H, 2I, 2J ... cells, 2 ... capacitors, 3A, 3B, 3C, 3D, 3C, 3E, 3
F, 3G, 3H, 3I, 3J: voltmeter, 4: control circuit,
5A, 5B, 6: switching circuit, 7A, 7B: capacitor, battery module, 8: short circuit prevention circuit, CB: assembled battery.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G016 CA03 CB11 CB12 CC01 CC04 CC12 CC27 CD10 5G003 AA01 BA03 CA11 CC04 CC08 DA12 DA13 GA01 GC05 5H030 AA03 AA04 AA10 AS08 BB01 BB21 FF43 FF44

Claims (3)

[Claims] 1. A battery pack comprising a plurality of unit cells each comprising a plurality of unit cells and connected in series to each other to form an assembled battery, wherein each group cell includes a plurality of unit cells connected in series and an auxiliary A charger / discharger, a first state-of-charge detecting means for detecting a state of charge of each of the unit cells, and a unit cell having the highest charge level or one or more cells including the unit cell having the highest charge level After selecting an appropriate number of cells as the first series battery group and connecting the cells having the highest charge level or the first series battery group to the auxiliary charger / discharger in parallel, A cell having the lowest charge level or a smaller number of adjacent cells including the cell having the lowest charge level than the first series battery group is selected as the second series battery group, and the most chargeable battery is selected. Simple low level A first switching connection means for repeating a switching operation of connecting a battery or the second series battery group to the auxiliary charger / discharger in parallel, and a second state detecting a charge state of each group battery. A state-of-charge detection means, and a unit cell having the highest charge level among the group cells having the highest charge level, or one or more suitable cells adjacent to and including the unit cell having the highest charge level.
After selecting the series battery group having the highest charge level or the third series battery group in parallel with the auxiliary charger / discharger of the group battery having the highest charge level, The auxiliary charge / discharger of the group battery with the highest charge level is connected to the auxiliary charge / discharger of the group battery with the lowest charge level, and then the lowest charge level in the group battery with the lowest charge level at this time. A unit cell or a unit cell including the unit cell having the lowest charge level and selecting a smaller number of adjacent unit cells than the third series cell group as the fourth series cell group, and selecting the unit cell having the lowest charge level A second switching connection means for repeating a switching operation of connecting the fourth series battery group in parallel to the auxiliary charger / discharger of the group battery having the lowest charge level. The state of charge control device. 2. A battery comprising a plurality of unit cells each comprising a plurality of unit cells and connected in series to each other to form an assembled battery, wherein each group cell includes a plurality of unit cells connected in series;
Auxiliary charger / discharger, first state-of-charge detecting means for detecting the state of charge of each unit cell, unit cell having the highest charge level, or one or more cells including the unit cell having the highest charge level After selecting an appropriate number of cells as the first series battery group and connecting the cells having the highest charge level or the first series battery group to the auxiliary charger / discharger in parallel, A cell having the lowest charge level or a smaller number of adjacent cells including the cell having the lowest charge level than the first series battery group is selected as the second series battery group, and the charge level is selected. And a first switching connection means for repeating a switching operation of connecting the lowest unit cell or the second series battery group to the auxiliary charger / discharger in parallel, and detecting a state of charge of each of the group batteries. Second state of charge detection Means and a unit cell having the highest charge level in a group battery having a relatively high charge level among adjacent group batteries, or one or more suitable numbers including and adjacent to the unit cell having the highest charge level Is selected as a third series battery group, and the single battery having the highest charge level or the third series battery group is connected in parallel to the auxiliary charger / discharger of the group battery having the relatively high charge level. After the connection, a cell adjacent to another group battery in the one group battery of the adjacent group batteries or one or more cells including the unit cell adjacent thereto is connected to a fifth series battery group. And the unit cell having the lowest charge level among these, or the adjacent unit cell including the unit cell having the lowest charge level and having a smaller number than the third series cell group is referred to as a fourth cell. Select a series battery group, lower the most charge level unit cell to the fourth
Is connected in parallel to the auxiliary charger / discharger of the group battery having a relatively high charge level, and thereafter, the single cell or the fifth series battery group is connected to the group battery having a relatively low charge level. Connected in parallel to the auxiliary charger / discharger, and further including the cell having the lowest charge level at this time in the group battery having the relatively low charge level or the cell having the lowest charge level at this time. A smaller number of adjacent cells than the series battery group of the series are selected as the sixth series battery group, and the cells having the lowest charge level or the sixth series battery group are grouped with the relatively low charge level. And a second switching connection means for repeating a switching operation of connecting the battery in parallel to an auxiliary charger / discharger of the battery. 3. A plurality of group batteries each comprising a plurality of unit cells, connected to each other in series while sharing one or more unit cells, and forming a battery pack, wherein each group battery is connected in series. A plurality of cells connected to
Auxiliary charger / discharger, charge state detecting means for detecting the charge state of each unit cell, unit cell having the highest charge level, or 1 unit including and adjacent to the unit cell having the highest charge level
At least one unit cell is selected as a first series cell group, and the unit cell having the highest charge level or the first cell unit is selected.
After connecting the series battery group in parallel to the auxiliary charger / discharger,
At this point, the unit cell having the lowest charge level, or a smaller number of adjacent unit cells including the unit cell having the lowest charge level than the first series cell group is selected as the second series cell group, A charging state control device for an assembled battery, comprising: switching connection means for repeating a switching operation of connecting the unit cell having the lowest charge level or the second series battery group to the auxiliary charger / discharger in parallel.