JPH0564377A - Set battery charger - Google Patents

Abstract

PURPOSE:To prevent the deterioration or destruction of a set battery due to overcharging by controlling charging current to the set battery based on the temperature and terminal voltage of each battery cell group. CONSTITUTION:The terminal voltage and temperature of each battery cell group 10-1, 10 2,...,10-2 which constitute a set battery 10 are detected by cell voltage detecting circuits 11-1, 11-2,..., 11-n and temperature sensors 41-1, 41-2,...,41-n and the detected values are inputted into a current control/full charging judging circuit 12A. The current control/full charging judging circuit 12A decides whether there are any detected terminal voltage values that show full charging. When it detects that at least one of the battery cell groups 10-1-10-n shows full charging, a variable constant-current controlling circuit 13 stops the supply of charging current to the set battery 10. By this method, the deterioration or destruction of the battery due to overcharging can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery pack charging device in which a plurality of battery cells are connected in series, and more particularly to a battery pack charging device for a vehicle. More specifically, the present invention relates to an assembled battery charging device for charging an assembled battery configured by serially connecting a plurality of battery cell groups each including at least one battery cell.

[0002]

2. Description of the Related Art In recent years, electric vehicles driven by batteries have been developed. A battery mounted on a vehicle is required to have a small size, a light weight, a large output capacity, and the like, and as a battery satisfying these conditions, an assembled battery configured by connecting a plurality of battery cells in series is often used.

As described below with reference to FIGS. 7 to 12, such charging of the assembled battery is performed by connecting a series-connected battery cell between both terminals of the assembled battery in which a plurality of battery cells are connected in series. This is done by applying a voltage according to the number.

Further, in general, even if the battery is further charged after being fully charged, the energy input is not stored and is consumed for electrolysis of the electrolytic solution, so that reaction gas is generated and abnormal heat is generated. As a result, the life of the assembled battery is adversely affected. Therefore, when charging the battery, it is necessary to detect the fully charged state and not charge the battery thereafter.

In FIG. 7, the assembled battery 50 includes a plurality of Ni / Zn battery cells 50-1, 50-2, ..., 50.
-N is connected in series. A current for charging the assembled battery is supplied to the variable constant current control circuit 51 from the main power source 53. The variable constant current control circuit 51 controls the supplied current, and supplies the battery 50 with a scheduled charging current ICH.

The overvoltage detection circuit 52 detects the terminal voltage VBA of the assembled battery 50 in order to prevent overcharge, and FIG.
As shown in (a), when the detected value reaches the overvoltage level VTH, the overvoltage detection signal S1 is output to the variable constant current control circuit 5
Supply to 1.

In the variable constant current control circuit 51, as shown in FIG. 8B, when the overvoltage detection signal S1 is detected, the charging current ICH is cut off, or the current value close to the self-discharge current of the assembled battery 50 is set. Switch to trickle charging.

FIG. 9 shows a plurality of lead battery cells 60-1, 6
0-2 ..., 60-n assembled battery 6
It is the figure which showed the charging device of 0, The same code as the above,
Represents the same or equivalent parts.

In this example, the intermittent control circuit 61 controls the variable constant current control circuit 51 on the basis of the terminal voltage VBA of the assembled battery 60, and the loop-like intermittent charging as shown in FIG. To be taken.

In FIG. 10, a variable constant current control circuit 51 is provided.
First, as described above, a constant current is output until the detection terminal voltage VBA reaches the predetermined value V2, and as shown after that, a current that the detection terminal voltage VBA maintains the upper limit value V2 is output. As in the following, the charging current is linearly reduced until the detection terminal voltage VBA decreases from the upper limit value V2 to the lower limit value V1, and as it continues, the detection terminal voltage VBA is maintained at the lower limit value V1. To increase the charging current.

In such intermittent charging, when the above-mentioned time cycle exceeds the scheduled time, it is determined that the battery is fully charged and the charging is terminated.

FIG. 11 shows a plurality of Ni / Cd battery cells 7.
It is the figure which showed the charging device of the assembled battery 70 comprised by 0-1, 70-2 ..., 70-n, and the same code | symbol as the above represents the same or equivalent part.

The peak value detection circuit 71 detects the terminal voltage VBA of the assembled battery 70 in order to prevent overcharge, and when the detected voltage VBA reaches the peak value VP, as shown in FIG. 12 (a). , And outputs the peak detection signal S2 to the variable constant current control circuit 51.

When the peak detection signal S2 is input, the variable constant current control circuit 51 cuts the charging current ICH or charges at a current value close to the self-discharge current, as shown in FIG. 12 (b). Switch to trickle charging.

As described above, the conventional battery pack is charged until the terminal voltage VBA of the battery pack is detected and the detected terminal voltage VBA reaches a voltage indicating a fully charged state.

[0016]

In the above-mentioned prior art, whether the assembled battery has reached the fully charged state or not is determined using the terminal voltage VBA as a parameter. Therefore, if there is a variation in the capacity or charge amount of each battery cell that constitutes the assembled battery, the charging is not completed as a whole because the battery cell is not fully charged even if one battery cell is fully charged. Therefore, there is a problem in that charging is continued and as a result, overcharging occurs in a specific battery cell and the life of the assembled battery is significantly impaired.

Further, in the prior art, since the temperature of the battery cell is not taken into consideration when determining the charging start timing and setting the charging current value, the charging current exceeds the proper value, and the amount of oxygen generated in the battery cell is increased. May increase the charging efficiency and decrease the charging efficiency, or the internal pressure may increase, adversely affecting the life of the assembled battery.

An object of the present invention is to solve the above-mentioned problems of the prior art and to charge an assembled battery efficiently without causing excessive charging current or overcharging and without deterioration of life. Another object of the present invention is to provide an assembled battery charger.

[0019]

In order to achieve the above object, the present invention provides a battery pack including a plurality of battery cell groups each including at least one battery cell connected in series. In the charging device, the charging current to the assembled battery is controlled based on the temperature and terminal voltage of each battery cell group.

[0020]

According to the present invention, the charging current can be appropriately controlled according to the degree (rate) of charging of each battery cell group forming the assembled battery and whether or not they have reached full charge. As a result, it becomes possible to prevent deterioration or destruction of the assembled battery caused by excessive charging current or overcharging of the specific battery cell group.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of a battery charger which is an embodiment of the present invention.

In the figure, each battery cell group 10-1, 10-2, ..., 10-n that constitutes the assembled battery 10 includes at least one battery cell, and each cell group has its own terminal voltage. , 11-n for detecting the cell voltage are connected. In addition, it is desirable that the battery cells included in one battery cell group have as close as possible a capacity and a charge / discharge characteristic. Each cell voltage detection circuit 11-1 to 11-
The voltage values detected by n are all the current control circuit 1
Entered in 2.

The current control circuit 12 determines the optimum charging current based on the detection values of the cell voltage detection circuits 11-1 to 11-n. The variable constant current control circuit 13 adjusts the current output from the main power supply 14 and outputs the determined charging current ICH.

In such a configuration, when at least one of the battery cell groups 10-1 to 10-n is fully charged and the terminal voltage thereof rises, the voltage control circuit 12 causes the variable constant current control circuit 13 to operate. To stop charging. In response to the charge stop instruction, the voltage control circuit 12 or the variable constant current control circuit 13 stops the supply of the charge current to the assembled battery 10.

According to the present embodiment, the charging is stopped when at least one of the battery cell groups 10-1 to 10-n forming the assembled battery 10 is fully charged, so that the battery cell group is deteriorated due to overcharging. Or it will not be destroyed.

In this embodiment, the description has been made assuming that the supply of the charging current is stopped when the full charge is detected, but the present invention is not limited to this, and the full charge is detected. After that, trickle charging may be performed with a small current. By doing so, it is possible to continue charging the other fully charged battery cell groups to the fully charged state without adversely affecting the already fully charged battery cell groups.

FIG. 2 is a block diagram of a charging device according to another embodiment of the present invention, and the same reference numerals as those used above represent the same or equivalent parts.

In this embodiment, each battery cell group 10-
1, 10-2 ... 10-n include bypass circuits 15-1 to 15-1
5-n are respectively connected in parallel. As shown in FIG. 3, each of the bypass circuits 15-1 to 15-n acts to pass the charging current as the bypass current IBP when the terminal voltage VSL of the battery cell group becomes the full charging voltage VFU.

FIG. 4 is a circuit diagram showing an example of the configuration of the bypass circuit 15. As can be easily seen from the figure, a bypass circuit consisting of a resistor R1 and diodes D1, D2, D3 connected in series in the forward direction is connected in parallel to each battery cell group, and the sum of the forward voltages by the diodes D1 to D3 is It is set to be equal to the full charge voltage VFU of the battery cell group. The resistor R1 can be omitted.

FIG. 5 is a circuit diagram showing the configuration of another example of the bypass circuit 15. The base of the transistor Tr is connected to the connection point of the voltage dividing resistors R2 and R3 connected between both terminals of the battery cell group, and the collector of the transistor Tr is connected to one terminal of the battery cell group via the resistor R4. The emitter of the transistor Tr is connected to the other terminal.

According to the configurations shown in FIGS. 4 and 5, when the terminal voltage of the battery cell group rises to reach the full charge voltage VFU, the series-connected diodes D1 to D3 are turned on or the base voltage of the transistor Tr is turned on. Rises to an on state, so that the charging current to the battery cell group is bypassed by the diode and the transistor Tr. Therefore, even if the charging current TCH is supplied to the assembled battery, the fully charged battery cell group is not further charged, and overcharging is avoided.

FIG. 6 is a block diagram of a charging device according to still another embodiment of the present invention, in which the same symbols as those used above represent the same or equivalent parts.

In this embodiment, each battery cell group 10-
1, 10-2 ... 10-n, cell voltage detection circuits 11-1 to 11-n and current control circuit 18-
1 to 18-n, and variable constant current control circuits 19-1 to 19-1
9-n are connected to each of the variable constant current control circuits 19-1 to 19-1.
Each of 9-n is connected to the main power supply 12.

In such a configuration, when one of the battery cell groups 10-1 to 10-n is fully charged and its terminal voltage rises to a predetermined value, the voltage control corresponding to the battery cell group concerned. The circuit 12 instructs the variable constant current control circuit 13 to stop charging. In response to this, the variable constant current control circuit 13 stops supplying the charging current to the corresponding battery cell group.

According to this embodiment, since the charging is controlled for each of the battery cell groups 10-1 to 10-n forming the assembled battery 10, the battery cell group is deteriorated or destroyed due to overcharging. Not only is there no adverse effect, but since all the battery cell groups can be fully charged, the charge capacity of the assembled battery can be efficiently utilized.

Although the variable constant current control circuit 19 stops supplying the charging current when full charge is detected in the present embodiment, the present invention is not limited to this. Similarly to the above, trickle charging may be performed after full charge is detected.

FIG. 13 is a block diagram of a charging device according to still another embodiment of the present invention, in which the same symbols as those used above represent the same or equivalent parts. In this embodiment, the charging start timing is set to the temperature and AC of each battery cell group.
It is determined as a function of the elapsed time from (commercial) power supply connection, and the charging current value is set as a function of the terminal voltage and temperature of each battery cell group.

An AC power source is connected to the variable constant current control circuit 13 (either the AC plug 21 is inserted or A (not shown)).
When the C power switch is turned on), the standby timer 22 is activated and starts measuring elapsed time. .. 41-n, such as temperature-sensitive resistors, at appropriate places of the battery cell groups 10-1, 10-2 ,. Are attached, and the detection outputs T-1, T-2, ... Tn are supplied to the current control / full charge determination circuit 12A and the upper limit table / determination circuit 23. In the upper limit table / determination circuit 23, the upper limit value of the maximum temperature of the battery cell group that can allow the actual start of charging current supply to the assembled battery 10 is connected to the variable constant current control circuit 13 with the AC power source. Stored as a function of waiting time from.

The upper limit value is preferably determined from the following viewpoints. Generally, it is desirable to charge the battery at a temperature as low as possible from the viewpoints of efficiency, suppression of oxygen generation, and long life, but on the other hand, it is necessary to wait until the temperature of the battery after discharging has dropped sufficiently, so the charging time There is a problem that it becomes too long and not practical.

In the present invention, as a compromise, a current control circuit is used in an experiment of a vehicle battery charger using an assembled battery in which eight Ni-Zn battery cells connected in series are set as one group and four groups are connected in series. If the waiting time from when the AC power supply is connected to 13 to the start of the actual charging current supply is within 2 hours, the above upper limit value is set to 25 ° C. and the waiting time is 2 hours.
Above the time, set the upper limit to 40 ℃,
Practically good results were obtained. In this experiment, considering that it takes about 7 to 8 hours to fully charge, and that it is necessary to complete charging from the night before to the next morning,
The above upper limit was determined. Of course, it may be set to a value different from this, but in view of the above requirements, the longer the waiting time, the higher the upper limit value should be set.

The upper limit value table / determination circuit 23 reads the upper limit value corresponding to the waiting time from the table and
The upper limit value is set to the detected temperatures T-1 and T- of each battery cell group.
2, ... Tn, when all the detected temperatures are equal to or lower than the upper limit value, the variable constant current control circuit 13 is activated. As a result, the charging of the assembled battery 10 is actually started.

The control of the charging current is performed by the current control / full charge determination circuit 12A as follows. FIG. 14 is a diagram showing the state of charge current control, that is, the change in charge mode according to this embodiment.

At time t0, the actual charging does not start immediately even if the AC power source is connected to the current control circuit 13, and as described above, the charging is performed according to the elapsed time and the temperature of each battery cell group. The start timing t1 is determined, and the first-stage charging with the first constant current value is started. It is desirable that the value of the first constant current is set as large as possible within a range in which oxygen generation in the cell can be suppressed to an allowable limit. In the experiments conducted by the inventors, the value of the first constant current was set to 6.6A.

As the charging progresses, the terminal voltage of each battery cell group gradually rises. Similarly to the above-described embodiments, the terminal voltage of each battery cell group 10-1, 10-2, ... Is detected by the cell voltage detection circuits 11-1, 11-2 ,. It is supplied to the determination circuit 12A. At the timing t2 when the terminal voltage rises to the intermediate target voltage corresponding to the value at the time of scheduled% (normally 80 to 90%) charging, the second stage charging mode is switched. Since the terminal voltage of the battery cell group decreases as the battery temperature rises, temperature compensation as in the following equation (1) is necessary. {0 ° C./Terminal voltage at scheduled charging −0.016 [v / ° C.] × battery temperature [° C.]} (V) (Equation 1) In the above experiments by the inventors, the planned charging percentage was 90. Therefore, the following formula is adopted.

{15.1-0.016 [v / ° C.] × battery temperature [° C.]} (V) In the second-stage charging, the maximum value of the terminal voltage of the battery cell group is the value obtained by the equation (1). That is, constant voltage mode charging is performed so that the maximum terminal voltage at time t2 is maintained. In the second-stage charging, as the charging progresses over time, the charging current gradually decreases, while the oxygen generation in the cell increases with the charging. At the time t3 when the oxygen generation in the cell reaches the limit value, the mode is switched to the constant current charging mode of the third stage. The charging current value when the oxygen generation reaches the limit value is experimentally confirmed in advance, and this value can be used as the current target value for switching to the third-stage charging.
In the above experiments by the present inventors, the charging current at this time was 3.4.
It was A.

In the third-stage charging, constant-current charging is performed so as to suppress the oxygen generation in the cell within the limit value while maintaining the charging current value at the time of switching, that is, the second constant-current value.
As the charging progresses, the maximum terminal voltage of the battery cell group gradually rises. Charging is completed at timing t4 when the maximum terminal voltage of the battery cell group has risen to a voltage corresponding to the value at the time of 100% charging. The target value of the maximum terminal voltage at this time can be calculated by the following equation (2). {0 ° C./100% charge terminal voltage −0.016 [v / ° C.] × battery temperature [° C.]} (V) (Equation 2) Adopted the formula.

{15.7-0.016 [v / ° C.] × battery temperature [° C.]} (V) It should be noted that the completion of charging is performed by a known appropriate method, for example, a rapid increase in the internal pressure in the cell or a delta peak. The maximum terminal voltage of the battery cell group for determining the completion of charging can be experimentally known in advance. Charging may be stopped immediately after charging is completed, or trickle charging may be continued as described above. It is desirable to turn on the charging lamp (not shown) after the power supply of the variable constant current control circuit 13 is turned on until the charging is completed, that is, during the charging standby and the first to third stage charging periods.

It is desirable that the charging be stopped not only when the third stage charging is completed and full charging is detected as described above, but also under the following conditions. (1) When the scheduled time (for example, 12 hours) or more has elapsed from the start of charging. (2) Scheduled time (for example, 2 hours) from the start of the third stage charging
When the above has passed. (3) When the terminal voltage of any of the battery cell groups drops by a predetermined value (for example, 0.5 V) or more during charging. (4) When the load side (motor 24) main switch (25 in FIG. 13) of the assembled battery 10 is turned on. (5) When the charging (commercial) power supply is cut off.

The current sensor 42 detects the charge / discharge current of the assembled battery 10. The detected current signal is supplied to the remaining amount calculation circuit 43 and integrated, and the calculated battery remaining amount signal is transferred to the remaining amount meter 44 (for example, as a pulse width modulation signal) and displayed. The remaining amount meter 44 is 100% charged "F" by the signal from the current control / full charge determination circuit 12A every time charging is completed as described above.
The calibration is set to "ULL". The remaining amount calculation circuit 43 also displays, for example, by turning on the reserve lamp 45 when the remaining amount of the battery becomes equal to or less than the predetermined value and recharging becomes necessary.

The NG signal generator 47 outputs the NG signal when the remaining battery level is reduced to a predetermined value (for example, the remaining amount is 0) or when one of the lowest terminal voltages of the battery cell group drops below the predetermined value. Is generated, the motor switch 25 is opened, and the motor 24 is stopped. The minimum terminal voltage is
For example, it can be determined by the following equation (3). {11.2-0.016 [v / ℃] × battery temperature [℃]} (V)
When the motor 24 is included in the load of the battery 10, the regeneration permission / inhibition signal generator 48 generates the regeneration permission / inhibition signal RC according to the maximum terminal voltage of each battery cell group, and the maximum voltage is the predetermined value. In the above case, regenerative charging is prohibited to protect the battery 10 from overcharging. In the experiments conducted by the inventors of the present invention, for example, when the regeneration permission / inhibition signal RC is equal to or higher than a predetermined value determined by the equation (4), the regenerative charging is prohibited, and conversely, the equation (5) is used. When the value is less than the planned value determined by, regenerative charging is enabled. {15.1-0.016 [v / ℃] × battery temperature [℃]} (V)
... Formula (4) {14.8-0.016 [v / ° C] × battery temperature [° C]} (V)
Equation (5) In the embodiment of FIG. 13, cell voltage detection circuits 11-1 and 11
The input side terminals of -2, ... Are directly connected to the terminals of each battery cell group, but for the purpose of shortening the wiring length and the like, as shown schematically in FIG. The measurement wiring of the cell voltage detection circuits 11-1 and / or 11-n connected to the battery cell terminals of the high voltage end and the low voltage end may be directly connected to the charging current wiring. In this case, reference numerals Ri1 and R in FIG.
The voltage drop caused by the internal resistance of the charging circuit wiring or the current sensor (hereinafter simply referred to as the charging wiring resistance) as equivalently indicated by i2 may cause a measurement error, and the above-mentioned charging control performance may be deteriorated. .. In this case, the cause of the measurement error can be eliminated as follows.

That is, first, immediately before the start of charging, the terminal voltages of the battery cell group-in particular, the battery cell groups 10-1 and 10-n at the high voltage end and the low voltage end of the assembled battery 10 are measured. This value is a value when no current actually flows in each wiring, and can be regarded as a true terminal voltage of the battery cell groups 10-1 and 10-n. Next, immediately after the start of charging by the first constant current I described with reference to FIG.
After 0 msec), the terminal voltage of the same battery cell group 10-1, 10-n is measured. At this time, as can be seen from FIG. 15, the true terminal voltage of each battery cell group and the wiring resistance Ri
The voltage of the sum of 1 and the voltage drop in Ri2 is measured. On the other hand, since each battery cell group is not actually charged, the terminal voltage should not change.

Therefore, by calculating the voltage difference between the first measured voltage value and the later measured voltage value, the voltage drop due to the charging wiring resistance can be detected, and this can be used as a correction value for the subsequent battery voltage measured value. Can be used as Furthermore, since the value of the charging wiring resistance can be calculated from the voltage difference and the value of the first current, even if the charging current changes, the voltage drop due to the charging wiring resistance is based on the charging current value and the charging wiring resistance value at that time. The same correction can be performed by calculating the minutes. The same correction can be applied to the terminal voltage measurement of the battery cell group connected to the intermediate position. Also, instead of the first constant current I, an appropriate known current value may be used.

As described above, the output of the current sensor is integrated by the remaining amount calculation circuit. However, since an operational amplifier is used for amplifying the output of the current sensor, an error is accumulated in the calculation result due to the offset of the operational amplifier. There is a risk that By storing the output of an operational amplifier or the like when the charge / discharge current is 0 and using this as an offset correction value, the error of battery charge / discharge current integration during motor operation is reduced, and the remaining battery level is monitored. The accuracy can be improved.

Charging start timing / mode setting, charging start / stop control, battery remaining amount monitoring, regenerative charging availability judgment, battery voltage / mode adopted in the embodiment shown in FIG.
It will be easily understood that the current calibration function and the like can be naturally applied to each of the above-described embodiments. Further, the portion surrounded by the dotted line in FIG. 13 can be configured by a microcomputer or the like.

[0056]

As is apparent from the above description, according to the present invention, the charging current is controlled depending on whether or not each battery cell group forming the assembled battery has reached full charge. It is possible to realize a quick and complete full charge while preventing deterioration or destruction of the battery due to charging.

[Brief description of drawings]

FIG. 1 is a block diagram of a charging device that is an embodiment of the present invention.

FIG. 2 is a block diagram of a charging device according to another embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation of FIG.

FIG. 4 is a diagram showing an example of the bypass circuit shown in FIG.

5 is a diagram showing another embodiment of the bypass circuit shown in FIG.

FIG. 6 is a block diagram of a charging device according to still another embodiment of the present invention.

FIG. 7 is a block diagram of a conventional technique.

FIG. 8 is a diagram for explaining the operation of the charging device in FIG.

FIG. 9 is a block diagram of a charging device according to the prior art.

FIG. 10 is a diagram for explaining the operation of the charging device in FIG.

FIG. 11 is a block diagram of the related art.

FIG. 12 is a diagram for explaining the operation of the charging device in FIG. 11.

FIG. 13 is a block diagram of a charging device according to still another embodiment of the present invention.

FIG. 14 is a diagram for explaining the operation of the embodiment of FIG.

FIG. 15 is a diagram showing a circuit configuration for compensating for a detection error due to wiring resistance when a terminal voltage of a battery cell group is detected in the present invention.

[Explanation of symbols]

10 ... assembled battery, 10-1 to 10-n ... battery cell group, 11-1 to 11-n ... cell voltage detection circuit,
12A ... Current control / full charge determination circuit, 13 ... Variable constant current control circuit, 14 ... Main power supply, 22 ... Standby timer, 23 ... Upper limit table / determination circuit, 24 ...
Motors, 41-1 to 41-n ... Temperature sensor, 42 ...
Current sensor, 43 ... Remaining amount calculation circuit, 44 ... Remaining amount memory
Ta

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Nakazawa, 1-4-1, Chuo, Wako, Saitama, Ltd. Inside Honda R & D Co., Ltd.

Claims (14)

[Claims] 1. An assembled battery charging device configured by connecting a plurality of battery cell groups in series with each other, each battery cell group including at least one battery cell, and the battery based on the terminal voltage of each battery cell group. An assembled battery charging device characterized by controlling a charging current to a cell group. 2. A battery cell group voltage detection means for detecting a terminal voltage of each battery cell group, and a charging current value supplied to the battery cell group based on the terminal voltage detected by the battery cell group voltage detection means. The assembled battery charging device according to claim 1, further comprising: a current control unit that determines a charge current, and a current supply unit that supplies the charge current having the determined value to the battery. 3. A bypass unit, which is connected in parallel to each battery cell group and bypasses a charging current to the battery cell group, wherein the bypass unit has a terminal voltage of a certain battery cell group substantially equal to a full charge voltage. At this time, the assembled battery charging device according to claim 1, wherein the charging current to the battery cell group is bypassed. 4. A battery cell group voltage detection means for detecting a terminal voltage of each battery cell group, and a battery cell group provided uniquely corresponding to each battery cell group,
Based on the terminal voltage detected by each battery cell group voltage detection means, the current control means for individually determining the charging current to each battery cell group, and provided uniquely corresponding to each battery cell group,
2. A current supply unit that supplies the determined charging current to the battery cell group.
The assembled battery charger described. 5. The assembled battery charging device according to claim 1, wherein the charging current is determined as a function of the terminal voltage and the temperature of the battery cell group. 6. The maximum temperature of the battery cell group is determined in advance as a function of the elapsed time from when the charging AC power source is turned on, for determining the maximum temperature of the battery cell group for starting the supply of the charging current. 6. The assembled battery charging device according to claim 1, wherein the start of supply of charging current is made to stand by until the value becomes less than or equal to the upper limit value. 7. The battery pack charging apparatus according to claim 6, wherein the upper limit value is set to be higher as the elapsed time from when the charging AC power source is turned on is longer. 8. The charging of each battery cell group is performed with a constant large current until a terminal voltage of any one of the battery cell groups rises to a predetermined first predetermined voltage value as a function of temperature. The first-stage charging performed in the current mode and the terminal voltage indicating the maximum value of the battery cell group from the completion of the first-stage charging until the charging current decreases to a predetermined value is the first voltage. Constant voltage mode so that the planned voltage value is maintained.
Comparison between the second stage charging performed by the battery and the terminal voltage of one of the battery cell groups after the second stage charging is completed until the second predetermined voltage value rises as a function of temperature. Constant current mode
8. The combined battery charging device according to claim 1, wherein the combined battery charging device comprises a combination with a third-stage charging that is performed by a battery. 9. The charging current value in constant current mode charging is set so that oxygen generation in each battery cell due to the charging current is less than a predetermined amount. The assembled battery charger described in. 10. Termination of third stage charging, first stage or third stage
The method further comprises means for interrupting the charging current when a predetermined time has elapsed from the start of the stage charging and at least one of the voltage drops of the terminal voltage of any one of the battery cell groups is detected. Claim 1 to 9 characterized
The assembled battery charger according to any one of 1. 11. An assembled battery is a motor as a load,
And a means for regeneratively charging the assembled battery by the motor, further comprising means for inhibiting regenerative charging when the terminal voltage indicating the maximum value of the battery cell group is equal to or higher than a predetermined value. Item 11. The assembled battery charger according to any one of items 1 to 10. 12. A current sensor for detecting a charging / discharging current of an assembled battery, a remaining amount calculating circuit for integrating outputs of the current sensor, and a remaining amount meter for displaying the calculated remaining amount. 12. The battery pack charging according to claim 1, wherein the display of the remaining amount meter is calibrated in response to the full charge determination signal from the current control / full charge determination circuit. apparatus. 13. The battery cell group voltage detection means calculates the difference between the terminal voltages of the battery cell group immediately before the start of charging and immediately after the start of charging with a known current, and based on the obtained voltage difference, the subsequent battery cell group. The assembled battery charging device according to claim 2, wherein the detected voltage value is corrected. 14. The battery cell group voltage detection means calculates a difference between terminal voltages of the battery cell group immediately before starting charging and immediately after starting charging with a known current, and based on the obtained voltage difference and the value of the constant current. 5. The assembled battery charging device according to claim 2, wherein the charging wiring resistance is calculated, and the subsequent battery cell group voltage detection value is corrected based on the obtained charging wiring resistance value and charging current value.