WO2015004946A1

WO2015004946A1 - Charger

Info

Publication number: WO2015004946A1
Application number: PCT/JP2014/056148
Authority: WO
Inventors: 後藤　昌彦; 弘毅兵藤; 田渕　泰弘; 英裕山内; 和征榊原
Original assignee: 株式会社マキタ
Priority date: 2013-07-12
Filing date: 2014-03-10
Publication date: 2015-01-15
Also published as: JP6140557B2; JP2015019522A

Abstract

A charger capable of collectively or individually charging a plurality of battery packs (A, B) which can be used while electrically-connected in series, the charger being configured to: store effective charge capacities (MA, MB) up to which battery packs (MA, MB) can each be charged; set a prescribed charge capacity (Cmax) that is equal to or less than the smallest effective charge capacity (MA, MB) among the effective charge capacities (MA, MB) in the respective battery packs (A, B); and stop the charge when the charge capacity of respective battery packs (A, B) reaches the prescribed charge capacity (Cmax).

Description

Charger

The present invention relates to a charger that can charge a plurality of battery packs that are used in a state where they are electrically connected in series, or that can be charged one by one.

A battery pack charger used for electric tools and the like is disclosed in JP-A-2006-318682. The charger is configured to receive a signal from a temperature sensor provided in the battery pack and perform optimum charging control of the battery pack based on the signal.

The charger described above is configured so that the battery pack can be charged up to an effective charge capacity (limit charge capacity) that can be charged. For this reason, even if it is a plurality of battery packs used in a state where they are electrically connected in series, for example, each battery pack is charged to an effective charge capacity in the charger.

However, the effective charge capacity of each battery pack differs depending on the rated capacity of the battery pack. Further, even if the rated capacities of the battery packs are equal, the effective charge capacity may vary depending on the usage environment and the usage period of the battery pack.

For this reason, when these battery packs (for example, 18V) are connected in series to drive a power tool (36V), the remaining battery pack can be discharged if the battery pack with the smallest effective charge capacity cannot be discharged. Even in such a state, the electric tool cannot be driven. That is, when the remaining capacity of one battery pack becomes zero, even if the remaining battery pack has a remaining capacity, the power of the remaining battery pack cannot be used.

Therefore, in the case of a plurality of battery packs used in a state of being connected in series, if each battery pack is charged to the effective charge capacity, charging time and power are wasted.

The present invention has been made to solve the above-described problems, and the problem to be solved by the present invention is that power remaining unused in a plurality of battery packs used in a state of being connected in series. It is to eliminate the amount of battery pack charging time and waste of power.

According to one aspect of the present invention, a plurality of battery packs that are used in a state where they are electrically connected in series are collectively or can be charged one by one, and the plurality of battery packs are configured. For each battery pack, an effective charge capacity that can be charged is obtained, a specified charge capacity that is equal to or less than the smallest effective charge capacity among the effective charge capacities in each battery pack is set, and It is configured to be able to stop charging when the charging capacity reaches a specified charging capacity.

That is, it is configured to set a specified charging capacity that is equal to or less than the smallest effective charging capacity among the effective charging capacities in each battery pack, and to stop charging when the charging capacity of the battery pack reaches a specified charging capacity. ing.

For this reason, the same amount of electric power is charged in all of the plurality of battery packs, and the remaining capacity of the plurality of battery packs connected in series to the power tool becomes zero at substantially the same time. Therefore, the amount of power that remains unused is eliminated, and the battery pack charging time and waste of power can be saved.

According to another aspect, the battery pack includes a charging port to which a plurality of battery packs are respectively connected, and is configured to be able to stop charging when the charging capacity of all the battery packs reaches a specified charging capacity. To do.

As described above, since the charging port to which each of the plurality of battery packs is connected is provided, the charging amount can be adjusted by simultaneously charging the battery packs, so that the charging time can be shortened.

According to another aspect, a charging port to which one of a plurality of battery packs is connected is provided, and the charging can be stopped when the charging capacity of the one battery pack reaches a specified charging capacity. It is characterized by.

Thus, even when the charging port is a single charger, the charge amounts of a plurality of battery packs used in a state of being connected in series can be made the same.

According to another aspect, the effective charge capacity of each battery pack is determined using the rated capacity of the battery pack.

According to another aspect, the effective charge capacity of each battery pack is determined from the history data of the battery pack. Thus, the memory area of the microcomputer of the charger can be reduced by using the history data of the battery pack.

According to another aspect, the charging control is performed so that the charging completion time of each battery pack is the same.

According to another aspect, after the charge capacities of the respective battery packs become equal, the respective battery packs are charged in order at a constant capacity.

According to another aspect, the battery packs are charged with a constant charging current after the charge capacities of the battery packs become equal.

Therefore, even when charging of a plurality of battery packs is interrupted, each battery pack is charged with substantially the same amount of power.

Therefore, even when the charging of the battery pack is interrupted in the middle, the remaining capacity of the battery packs A and B connected in series to the electric tool (not shown) becomes zero almost at the same time.

According to another aspect, a control for stopping charging when a charging capacity of the battery pack reaches a specified charging capacity and a control for stopping charging when the charging capacity of the battery pack reaches an effective charging capacity can be switched and executed. It is comprised by these.

For this reason, it is possible to charge a plurality of battery packs used in a state of being connected in series and a battery pack used singly with a single charger.

According to the present invention, in a plurality of battery packs that are used in a state of being connected in series, there is no remaining electric energy that is not used, and it is possible to eliminate waste of charging time and waste of power of the battery pack.

It is a whole perspective view of the charger concerning Embodiment 1 of the present invention. 2 is a block diagram of a charger according to Embodiment 1. FIG. It is a time chart showing ON / OFF of the control power supply in the said charger. It is a circuit diagram of the indicator in the charger. It is a schematic diagram showing the charging operation of the said charger. It is a graph showing the relationship between the charge amount of the said charger, and charging time. It is a flowchart showing operation | movement of the said charger. It is a flowchart showing operation | movement of the said charger. It is a schematic diagram showing the charging operation of the charger which concerns on the example of a change. It is a graph showing the relationship between the charge amount of the charger which concerns on the example of a change, and charging time. It is a flowchart showing operation | movement of the charger which concerns on the example of a change. It is a flowchart showing operation | movement of the charger which concerns on the example of a change.

Embodiments of the present invention will be described with reference to FIGS. The battery charger 10 according to the present embodiment includes, for example, two battery packs 60 (hereinafter, referred to as a battery pack 60) used in a power tool (not shown) having a rated DC of 36V configured such that two battery packs 60 having a rated DC of 18V can be connected. , Battery 60). Here, front and rear, right and left, and top and bottom in the figure correspond to front and rear, right and left, and top and bottom of the charger.

The charger 10 is configured to be able to charge the batteries 60 with two rated DC 18V batteries 60 connected. As shown in FIG. 1, the charger 10 includes two sets of charging ports 12 (A, B) configured to be connectable to the battery 60.

When the battery 60 is connected to the charging port 12 (A, B), the left and right slide rails (not shown) of the battery 60 are fitted to the left and right receiving rails 13 of the charging port 12, and the battery 60 is connected to the charging port. 12 is slid from the rear side to the front side. As a result, the terminal cover 16 of the charging port 12 is pushed by the battery 60 and slides forward (in the opening direction) against the spring force.

In the process of sliding the battery 60 to the forward limit position, the positive and negative connection terminals and the connector (not shown) of the battery 60 are connected to the positive and negative connection terminals (not shown) and the connector (not shown) of the charging port 12. Will be connected to each.

Thereby, the battery 60 and the charging port 12 of the charger 10 are mechanically and electrically connected.

A partition wall 19 is formed between the leftmost charging port 12 (charging port A) and the right charging port 12 (charging port B), and a first indicator 21 is formed on the front inclined surface 19a of the partition wall 19. And a second display 22 is provided.

The 1st indicator 21 is a indicator which displays the charge state etc. of the battery 60 (battery A) connected to the charge port A, and displays the green LED 21a arranged on the upper side and the red LED 21b arranged on the lower side. I have.

The second display 22 is a display for displaying a charging state of the battery 60 (battery B) connected to the charging port B, and includes an upper green LED 22a and a lower red LED 22b.

2, the charger 10 includes a microcomputer 25 (microcomputer A), a microcomputer 26 (microcomputer B), a power supply circuit 27, and a switching circuit 28.

The power circuit 27 is a circuit that converts AC power supplied from a household outlet (not shown) through the power cord section 29 into DC power for charging.

The switching circuit 28 can switch and supply the DC power for charging the power supply circuit 27 to the battery A connected to the charging port A or the battery B connected to the charging port B based on a signal from the microcomputer A. It is configured as follows.

The microcomputer A is a part that controls charging of the battery A connected to the charging port A, and is configured to operate the power supply circuit 27 and the switching circuit 28 based on a program stored in the memory so as to perform charging. Yes.

In addition, the microcomputer A is configured to operate the power supply circuit 27 and the switching circuit 28 based on the data transmitted from the microcomputer B.

Further, the microcomputer A is configured to monitor the connection state of the battery A to the charging port A and the charging state of the battery A and output a signal to the first display 21.

The microcomputer B is a part that controls charging of the battery B connected to the charging port B, transmits data to the microcomputer A, and operates the power supply circuit 27 and the switching circuit 28 via the microcomputer A to operate the battery B. It is comprised so that it can charge.

Further, the microcomputer B is configured to monitor the connection state of the battery B to the charging port B and the charging state of the battery B and output a signal to the second display 22.

Further, the microcomputer A is configured to be able to turn on and off the control power supply VccA used when charging the battery A in accordance with the connection state of the battery A to the charging port A, the charging state, the charging suspension state, and the like. .

Similarly, the microcomputer B is configured to be able to turn on and off the control power supply VccB used when charging the battery B according to the connection state of the battery B to the charging port B, the charging state, the charging suspension state, and the like. Yes.

For example, as shown in FIG. 3, when the battery A is set (connected) to the charger 10 and charging of the battery A is started, the control power supply VccA used when charging the battery A is turned on. Become. When the charging of the battery A is completed, even if the battery A is set, the control power supply VccA is turned off after confirming the state of the battery A for a certain period of time.

Further, when the battery B is set to the charging port B while the battery A is being charged, the control power supply VccB is quickly turned off after the control power supply VccB is turned on for a predetermined time for checking the state of the battery B. When charging of the battery B is started, the control power supply VccB is turned on. Thus, since the control power supplies VccA and VccB are turned on only when necessary, waste of power can be saved.

The first display 21 is a display that displays the state of charge of the battery A and the like. For example, the red LED 21b is turned on while the battery A is being charged, and the green LED 21a is turned on when charging is completed.

The second display 22 is a display that displays the charging state of the battery B, and is configured so that, for example, the red LED 22b is lit while the battery B is being charged, and the green LED 22a is lit when the charging is completed.

As shown in FIG. 4, the LED 21a, LED 21b of the first display 21 and the LED 22a, LED 22b of the second display 22 are connected in series to the dedicated power supply VLED for LED via the constant current circuit 23. It is connected. Transistors T21a, T21b, T22a, and T22b are connected to each LED in parallel.

That is, while the battery A is being charged, the red LED 21b of the first display 21 is turned on when the transistor T21b is turned off, and the green LED 21a is turned off when the transistor T21a is turned on. On the contrary, when the charging of the battery A is completed, the red LED 21b of the first indicator 21 is turned off when the transistor T21b is turned on, and the green LED 21a is turned on when the transistor T21a is turned off.

The operation of the second indicator 22 for the battery B is the same as the operation of the first indicator 22 for the battery A. Thus, since a plurality of (four) LEDs are connected to the dedicated power supply VLED via the constant current circuit 23 in a state where they are connected in series, even if all four LEDs are lit, there is no difference. A current of the same magnitude as that when the LED of the base is turned on flows. For this reason, power consumption can be suppressed in a circuit using a large number of LEDs.

Next, the operation of the charger 10 will be described based on the schematic diagram showing the charging operation in FIG. 5, the graph showing the relationship between the charge amount and the charging time in FIG. 6, and the flowcharts in FIGS. 7 and 8 are prepared on the assumption that the batteries A and B are connected to the charging ports A and B of the charger 10 almost simultaneously. Here, the processing shown in FIGS. 7 and 8 is executed based on a program stored in the memories of the microcomputers A and B of the charger 10.

First, when the battery A is connected to the charging port A of the charger 10 (FIG. 7, step S101 YES), the current charging capacity (remaining capacity CAstart) of the battery A, the effective charging capacity MA, and history information of the battery A Are stored (step S102 in FIG. 7). Here, the effective charging capacity MA is a capacity that allows the battery A to be charged to the limit.

When battery B is connected to charging port B of charger 10 (FIG. 7, step S103 YES), current charging capacity of battery B (remaining capacity CBstart), effective charging capacity MB, and history information of battery B Are stored (step S104 in FIG. 7).

As shown in FIG. 5, the battery A and the battery B are batteries having the same rated capacity, but since the battery B is more deteriorated than the battery A, the effective charge capacity (limit charge capacity) of the battery A is large. MA is larger than the effective charge capacity (limit charge capacity) MB of battery B. Further, the remaining capacity CAstart of the battery A is assumed to be smaller than the remaining capacity CBstart of the battery B as shown in FIG.

When the history information of the batteries A and B is stored in this way, the effective charge capacity MA of the battery A and the effective charge capacity MB of the battery B are compared, and the smaller one is stored as the specified charge capacity Cmax ( FIG. 7 Step S105). As shown in FIG. 5, since the effective charging capacity MA> the effective charging capacity MB, the effective charging capacity MB of the battery B is set to the specified charging capacity Cmax.

Here, the specified charging capacity Cmax can be set to a value smaller than the effective charging capacity MB of the battery B.

Next, the remaining capacity CAstart of the battery A and the remaining capacity CBstart of the battery B are compared (step S106 in FIG. 7). Since CAstart <CBstart (FIG. 7, step S106 YES), first, the battery A is charged (see FIG. 7, step S107, FIG. 5, FIG. 6, N1). When the current charging capacity CAnow of the battery A becomes equal to the current charging capacity CBnow (remaining capacity CBstart) of the battery B by charging (step S109 YES in FIG. 7), the battery A enters a charging suspension state (step S110 in FIG. 7).

Here, if the remaining capacity CAstar of the battery A is larger than the remaining capacity CBstart of the battery B (FIG. 7, step S106 NO), the battery B is charged (step S108 in FIG. 7). When the current charging capacity CBnow of the battery B becomes equal to the current charging capacity CAnow of the battery A due to charging (step S109 YES in FIG. 7), the battery B enters a charging suspension state (step S110 in FIG. 7).

At this stage, as shown by N1 in FIGS. 5 and 6, since the battery A is charged and the battery A is in the charging halt state (step S111 YES in FIG. 8), the battery B is then charged. (See FIG. 8, Step S112, FIG. 5, FIG. 6, N2). When a certain amount of charging for the battery B is completed (FIG. 8, step S113: YES), the battery B enters a charging suspension state (FIG. 8, step S114).

Next, the battery A is charged (see step S115 in FIG. 8, N3 in FIG. 5 and FIG. 6). When a certain amount of charge is performed on battery A (YES in step S116 in FIG. 8), battery A enters a charging suspension state (step S117 in FIG. 8).

At this stage, as shown in FIGS. 5 and 6, since neither the battery A nor the battery B is charged to the specified charge capacity Cmax, the determination in step S118 in FIG. 8 is NO and the determination in step S120. NO, the determination in step S121 is NO, and the battery B is charged in step S112 of FIG. 8 (see N4 in FIGS. 5 and 6).

As described above, the processes of steps S112 to S117, step S118 (NO), step S120 (NO), and step S121 (NO) in FIG. (Refer to FIG. 5, FIG. 6, N5, N6,..., Nn, Nn + 1).

For example, when the current charging capacity CAnow of the battery A becomes larger than the specified charging capacity Cmax (step S118 YES in FIG. 8), the charging of the battery A is completed (step S119).

Next, in FIG. 8, step S120, the current charge capacity CBnow of the battery B and the specified charge capacity Cmax are compared. If CBnow <Cmax (FIG. 8, step S120: NO), it is determined in step S121 that charging of one battery A is completed. As described above, since charging of the battery A is completed (step S121 YES in FIG. 8), the battery B is charged in step S122. When the current charging capacity CBnow of battery B> the specified charging capacity Cmax (step S120 YES in FIG. 8), charging of battery B is completed (step S123).

Thus, the batteries A and B can be charged up to the specified charge capacity Cmax. Further, since the charging is performed alternately, even when the charging is stopped halfway, the battery A and the battery B are charged with substantially the same amount of power.

According to the charger 10 according to the present embodiment, the specified charging capacity Cmax smaller than the smallest effective charging capacity MA, MB in each of the batteries A, B is set, and the charging capacity of the batteries A, B is set. Is configured to be able to stop charging when it reaches the specified charging capacity Cmax. For this reason, the plurality of batteries A and B are charged with the same amount of electric power, and the remaining capacity of the plurality of batteries A and B connected in series to the electric tool (not shown) becomes almost zero at the same time. .

Accordingly, the amount of power that is not used is eliminated, and the charging time of the batteries A and B and the waste of power can be saved.

Further, since the effective charging capacities MA and MB of the batteries A and B are determined using the battery history data, the storage area of the

microcomputers

25 and 26 of the charger 10 can be reduced.

Further, even when the charging of the batteries A and B is interrupted in the middle, each battery is charged with substantially the same amount of power. Therefore, even when the charging of the batteries A and B is interrupted in the middle, the remaining capacity of the batteries A and B connected in series to the electric tool (not shown) becomes zero almost at the same time.

Hereinafter, a charger according to Embodiment 2 of the present invention will be described with reference to FIGS. The charger 10 according to the present embodiment is different from the charger 10 according to the first embodiment in a method of charging the batteries A and B, and the basic configuration is the same as that of the charger 10 according to the first embodiment.

Also in the case of the charger 10 according to the present embodiment, when the batteries A and B are connected to the charging ports A and B of the charger 10 (FIG. 11, steps S141 and 143 YES), the remaining capacity of the batteries A and B ( (Remaining capacity CAstart, CBstart), effective charge capacity MA, MB that can be charged, history information of the batteries A, B, etc. are stored (FIG. 11, steps S142, 144).

Then, the effective charge capacity MA of the battery A and the effective charge capacity MB of the battery B are compared, and the smaller one is stored as the specified charge capacity Cmax (step S145 in FIG. 11). As shown in FIG. 9, since the effective charging capacity MA> the effective charging capacity MB, the effective charging capacity MB of the battery B is set to the specified charging capacity Cmax.

Next, the battery A and the battery B are charged with an optimum current suitable for charging the respective batteries (step S146). That is, as shown in FIGS. 9 and 10, the battery A is charged with the target charging current I1, and the battery B is charged with the target charging current I2. Here, current I1> current I2.

At the present stage, as shown in FIGS. 9 and 10, since the current charging capacities CAnow and CBnow of the batteries A and B are smaller than the specified charging capacity Cmax (step S147 NO in FIG. 11), the current charging of the battery A is performed in step S148. It is determined whether or not the capacity CAnow and the current charging capacity CBnow of the battery B are equal. If the current charging capacity CAnow of the battery A is smaller than the current charging capacity CBnow of the battery B (see timing T1 in FIG. 10, FIG. 11, step S148, NO), the target charging current between the battery A and the battery B in step S146 in FIG. Charging by I1 and I2 is continued.

Then, when the processing from step S146 to step S148 in FIG. 11 is repeated and the current charging capacity CAnow of battery A becomes equal to the current charging capacity CBnow of battery B (see timing T2 in FIG. 10, YES in step S148 in FIG. 11), the battery. The target charging current I1 (> I2) of A is limited to the target charging current I2 of the battery B (FIG. 12, step S150, YES, step S151). Then, the battery A and the battery B are charged with the same target charging current I2 (FIG. 12, step S154).

In the state where the batteries A and B are charged with the same target charging current I2 (see timing T3 in FIG. 10), the current charging capacities CAnow and CBnow of the batteries A and B are smaller than the specified charging capacity Cmax (FIG. 12, step S155 NO) Step S157 NO), since the charging of the battery is not completed (FIG. 12, Step S158 NO), the processes up to Step S154, Step S155, Step S157, and Step S158 are repeatedly executed.

And, for example, when the current charge capacity CAnow of the battery A becomes larger than the specified charge capacity Cmax (FIG. 12, step S155 YES), the charging of the battery A is completed (see timing T4 in FIG. 10, FIG. 12, step S156). Further, when the current charging capacity CBnow of the battery B becomes larger than the specified charging capacity Cmax (step S157 YES in FIG. 12), the charging of the battery B is completed (see timing T4 in FIG. 10, step S160 in FIG. 12).

Even when the charging of one battery is completed, if the current charging capacity Cnow of the other battery is smaller than the specified charging capacity Cmax (FIG. 12, step S157 NO), the determination in step S158 is YES, and the other battery Is continued (FIG. 12, step S159). When the current charging capacity Cnow of the other battery becomes larger than the specified charging capacity Cmax (FIG. 12, step S157 YES), the charging of the other battery is completed (step S160 in FIG. 12).

Here, in the present embodiment, the case where the target charging current I1 of the battery A is larger than the target charging current I2 of the battery B is illustrated, but when the target charging current I1 <the target charging current I2, The determination in step S151 is NO, and the target charging current I2 of the battery B is limited to the target charging current I1 of the battery A (FIG. 12, step S153).

Further, in the present embodiment, an example is shown in which the current charging capacity CAnow of the battery A and the current charging capacity CBnow of the battery B are equal before the charging of the batteries A and B is completed. However, before the battery A is charged with the target charge current I1 and the battery B is charged with the target charge current I2, the current charge capacity CAnow of the battery A and the current charge capacity CBnow of the battery B become equal. If the current charging capacities CAnow and CBnow of the batteries A and B become larger than the specified charging capacity Cmax (step S147 YES in FIG. 11), the charging of the batteries A and B is completed at this time ( FIG. 11 Step S149).

In the case of the charger 10 according to the present embodiment, the charging completion times of the batteries A and B are equal (see timing T4 in FIG. 10).

Here, the present invention is not limited to the first and second embodiments, and can be modified without departing from the gist of the present invention.

For example, in the first and second embodiments, the charger 10 including two sets of charging ports 12 is illustrated, but the present invention can also be applied to a charger including three or more sets of charging ports 12.

In the first and second embodiments, an example in which the smaller of the effective charge capacities MA and MB of the batteries A and B is defined as the specified charge capacity Cmax and the batteries A and B are charged to the specified charge capacity Cmax is shown. However, the charger 10 may be provided with a mode changeover switch 25s (see FIG. 2) or the like so that the battery can be switched between charging to the specified charging capacity Cmax or charging to the effective charging capacity MA, MB. good.

In the first and second embodiments, the charger 10 including two sets of the charging ports 12 is illustrated, but the present invention can be applied to the case where the charging port 12 is only one set.

Specifically, the battery A inserted first is charged, and the effective charging capacity of the battery A when the charging is completed is stored in the charger 10. Next, the effective charging capacity of the battery B inserted into the charger 10 is acquired, and this is compared with the effective charging capacity of the battery A stored earlier, and the smaller one is set as the specified charging capacity. And you may make it charge the battery B to a regulation charge capacity. Further, by performing the same process for the battery C inserted next to the battery B, the smallest effective charge capacity can be set as the specified charge capacity.

Here, the specified charging capacity may be stored in a nonvolatile memory of the charger 10. In this case, it is preferable to use a mode changeover switch 25s (see FIG. 2) or the like for the charger 10. Further, when it is better to clear the specified charge capacity every time the charger 10 is reset, the specified charge capacity may be stored in the volatile memory.

In the present embodiment, an example in which charging is performed using the dedicated charger 10 has been described. However, a similar charging function is provided in a tool box for storing tools, batteries, and the like, and the battery is stored in the tool box. It is also possible to charge the battery while it is running.

Claims

It is a charger that can charge a plurality of battery packs used in a state where they are electrically connected in series, or can be charged one by one.
For each of the battery packs constituting the plurality of battery packs, an effective charge capacity that can be charged is obtained, and a specified charge capacity that is equal to or less than the smallest effective charge capacity among the effective charge capacities in each battery pack is set. A charger configured to stop charging when the charging capacity of each of the battery packs reaches a specified charging capacity.
The charger according to claim 1, wherein
A charger comprising a charging port to which each of the plurality of battery packs is connected, and configured to be able to stop charging when the charging capacities of all the battery packs reach a specified charging capacity.
The charger according to claim 1, wherein
A charger configured to include a charging port to which one of the plurality of battery packs is connected, and to stop charging when a charging capacity of the one battery pack reaches a specified charging capacity.
The charger according to any one of claims 1 to 3,
A battery charger in which the effective charge capacity of each battery pack is determined using the rated capacity of the battery pack.
The charger according to any one of claims 1 to 3,
The charger in which the effective charge capacity of each battery pack is determined from the history data of the battery pack.
The charger according to claim 2, wherein
A charger in which charging control is performed so that the charging completion time of each battery pack is the same.
The charger according to claim 2, wherein
A charger that charges each battery pack in order by a fixed capacity after the charge capacity of each battery pack becomes equal.
The charger according to claim 6, wherein
A charger that charges each battery pack with a constant charging current after the charge capacity of each battery pack becomes equal.
The charger according to any one of claims 1 to 8, wherein
A control for stopping charging when the charging capacity of the battery pack reaches the specified charging capacity and a control for stopping charging when the charging capacity of the battery pack reaches the effective charging capacity are configured to be switched. Charger.