JPH04248332A - Battery pack - Google Patents

Abstract

PURPOSE:To charge each battery perfectly by providing each battery with a charge current control circuit thereby controlling the charging current for each battery independently. CONSTITUTION:A charger 12 charges a battery 16A at first and upon finish of charging operation thereof, a next battery 16B is charged In other words, upon finish of charging of the battery 16A switching circuits 22A, 22C and 24A are turned OFF while switching circuits 22B and 24B are turned ON. The charger 12 then feeds a charging current to the battery 16B and upon finish of charging thereof, next battery 16C is charged. In other words, the switching circuit 22A, 22B, 24A and 24B are turned OFF while the switching circuit 22C is turned ON and the battery 16C is charged. Consequently, the batteries can be operated efficiently.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to battery packs.
For example, it can be applied to a camera-integrated video tape recorder.

0002

[Prior Art] Conventionally, power supplies for camera-integrated video tape recorders and the like have been made to use battery packs.This type of battery pack can be used repeatedly by being charged using a charging device. It has been made possible.

That is, in this type of battery pack, a plurality of batteries are housed in a case and connected to each other to supply power at a predetermined voltage and current according to the power supply voltage and power consumption of the main body of the electronic device. As a result, the battery pack can be easily charged by, for example, connecting the entire battery pack to the main body of an electronic device to supply power, and then removing it from the main body of the electronic device and connecting it to a charging device.

0004

By the way, a simple method for charging this type of battery pack is to connect it to a constant current circuit and supply a constant charging current. However, this type of battery pack has a problem in that even if it is charged in this way, the built-in batteries cannot be completely charged and therefore cannot be used efficiently.

That is, as shown in FIG. 4, in a battery pack in which a plurality of batteries are connected in series, the batteries 2A to 2C and the internal resistances R1 to R of each battery 2A to 2C are
It can be expressed by an equivalent circuit in which 3 and 3 are connected in series.

[0006] At this time, since the conditions required for charging each battery 2A to 2C vary, when the battery pack 2 as a whole approaches full charge, for example, while battery 2A is fully charged, batteries 2B and 2C are still not fully charged. A situation arises where this is not the case. If you continue charging in this state,
The battery 2A would be overcharged, potentially damaging the battery pack 2 as a whole, and eventually charging had to be stopped before the battery pack 2 as a whole was completely charged.

The present invention has been made in consideration of the above points, and it is an object of the present invention to propose a battery pack that can fully charge each battery.

[0008]

[Means for Solving the Problems] In order to solve the problems, the present invention provides a plurality of batteries 16A, 16B,
16C is connected in series and stored, battery 16A, 16B
, 16C to a predetermined electronic device, and connects to a predetermined charging device 12 to charge batteries 16A, 16B,
In the battery pack 14 for charging 16C, the plurality of batteries 16A, 16B, 16C each have a control circuit 22A, 24A, 22B, which independently controls the charging current.
It has 24B and 22C.

[0009]

[Operation] Control circuit 22A that independently controls charging current;
24A, 22B, 24B, 22C, each battery 16A
, 16B, 16C, each battery 1
6A, 16B, and 16C can be fully charged.

0010

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

In FIG. 1, reference numeral 10 generally indicates a power supply device, and a charging device 12 is used to charge a battery pack 14 of a camera-integrated video tape recorder. That is, in the battery pack 14, batteries 16A to 16C of the same type are connected in series to power output terminals 18A and 18B, so that power can be supplied to the batteries 16A to 16C via the power output terminals 18A and 18B. ing.

On the other hand, when charging, the battery pack 14
In this case, charging current is input from the charging device 12 via power input terminals 20A and 20B. Each battery 16A
~16C connects the positive side electrode to the positive side power input terminal 20A through the switch circuits 22A to 22C, while connecting the negative side electrode to the negative side through the switch circuits 24A, 24B and the diode 26, respectively. Power input terminal 20
B.

[0013] The switch circuits 22A to 22C, 24A
, 24B are controlled by the charging device 12 to sequentially switch their contacts so that each battery can be fully charged. In other words, at the start of charging, the switch circuit 22
A and 24A are turned on, and the remaining switch circuits 22B, 22C, and 24B are turned off.

[0014] Accordingly, in the charging device 12, the battery 16A is first charged, and when the charging of the battery 16A is completed, the subsequent battery 16B is charged. That is, when charging of the battery 16A is completed, the switch circuits 22A, 22C and 24A are turned off, and the switch circuits 22B and 24B are turned on. Thereby, the charging device 12 supplies a charging current to the following battery 16B, and when the charging of the battery 16B is completed, the charging device 12 charges the following battery 16C.

That is, switch circuits 22A, 22B, 2
4A and 24B are turned off, and the switch circuit 22C is turned on, thereby charging the battery 16C. Therefore, in the battery pack 14, by providing the switch circuits 22A to 22C, 24A, and 24B, the batteries 16A to 16 are sequentially and independently operated.
By controlling the charging current of C, each battery 16A~
16C can be completely charged, and batteries 16A to 16C can be used more efficiently than before.

According to the above configuration, the switch circuit 22A
~ Each battery 16A ~ using 22C, 24A, and 24B
By independently controlling the charging current of 16C, each battery 16A to 16C can be completely charged, and the batteries can be used more efficiently.

In the above-described embodiment, a case has been described in which each battery is sequentially and independently charged by switching the contacts of the switch circuit, but the present invention is not limited to this, and the switch circuit may be formed of a semiconductor circuit. You can also do this.

Further, in the above-described embodiment, a case has been described in which charging is sequentially switched in the charging device 12, but the present invention is not limited to this, and as shown in FIG. You can also do this. That is, in the battery pack 30, each battery 16
A to 16C connect transistors 32A to 32C in parallel, respectively.

Each of the transistors 32A to 32C is a series circuit of a Zener diode 32A, a resistor 36A, and 38A, a Zener diode 32B, and a resistor 36B, 38A.
B series circuit, Zener diode 32C, resistor 36C
, 38C are connected between the collector and emitter, and their bases are connected to the connection midpoints of the resistors 36A, 38A, 36B, 38B, and 36C, 38C, respectively. As a result, the transistors 32A to 32C are sequentially turned on when the batteries 16A to 16C are charged and their terminal voltages rise above a predetermined voltage.

[0020] As a result, in the battery pack 30,
After starting charging the three batteries at the same time, the supply of charging current is stopped sequentially from the battery that has completed charging,
Each battery can be fully charged.

Further, in the above-described embodiment, a case was described in which a constant charging current was supplied, but the present invention is not limited to this, and as shown in FIG. Good too.

That is, in the battery pack 40, each battery 16A to 16C is connected to a transistor 42.
44 and a current control circuit formed by resistors 45 to 47 are connected so that the base voltage of transistor 44 can be controlled to independently control the charging current of each battery 16A to 16C. In this way, each battery 16A to 16
Even if the charging current of C is independently controlled, each battery 16A to 16C can be completely charged.

Further, in the above-described embodiments, the present invention was applied to a battery pack for a video tape recorder integrated with a camera, but the present invention is not limited to this, but can be widely applied to power supplies for various electronic devices. be able to.

[0024]

As described above, according to the present invention, each battery is provided with a charging current control circuit, and by independently controlling the charging current of each battery, each battery can be fully charged. Accordingly, it is possible to obtain a battery pack that can use batteries more efficiently than in the past.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing a charging device according to an embodiment of the present invention.

FIG. 2 is a connection diagram showing a second embodiment thereof.

FIG. 3 is a connection diagram showing a third embodiment thereof.

FIG. 4 is a connection diagram showing a battery pack.

[Explanation of symbols]

2, 14, 30, 40...Battery pack, 2A-2C
, 16A-16C...Battery, 22A-22C, 24
A, 24B...Switch circuit.

Claims (1)

[Claims] Claim 1: A plurality of batteries are connected in series and housed, and power from the batteries is outputted to a predetermined electronic device, and
A battery pack that is connected to a predetermined charging device to charge the batteries, wherein each of the plurality of batteries has a control circuit that independently controls charging current.