JPH05316662A - Charging device for nickel-cadmium storage battery - Google Patents

Abstract

PURPOSE:To appropriately charge a nickel-cadmium storage battery regardless of the residual capacity of the storage battery by discharging the residual capacity by connecting a discharge circuit when the storage battery is set in a battery device section and charging the battery for a fixed period of time by actuating a timer type charge circuit after disconnecting the discharge circuit when the discharged current drops from a referece value. CONSTITUTION:When a storage battery 1 is set in a battery mounting section and self-resetting type push-button switch 10 is operated, a discharge circuit 2 is connected to the storage battery 1 and a relay coil 6 is excited by the residual capacity of the storage battery 1 and self-holds the excited state. When the discharge from the storage battery 1 advances and the current discharged from the storage battery 1 becomes smaller than the value required for self- holding the coil 6, a relay contact 6a is turned off and the circuit 3 is disconnected from the storage battery 1. As a result, another relay contact 6b is turned on and the output of an AC-DC converter 4 is supplied to a timer type charge circuit 3 so as to charge the storage battery 1 by a guasi-constant-current system. When a fixed period of time elapses after starting the charging, a timer contact 9a is turned off and the charging operation ends.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device for a nickel-cadmium storage battery, and more particularly to a technical improvement for always charging an appropriate amount.

[0002]

2. Description of the Related Art Sealed nickel-cadmium storage batteries have become widely used in ordinary households. A sealed nickel-cadmium storage battery is used together with an ordinary dry battery (primary battery) as a power source for radios, tape recorders, transceivers, radio-controlled toys, and the like. A charging device connected to an AC power outlet of a general home is used for charging the storage battery.

[0003]

A general-purpose charging device for nickel-cadmium storage batteries is designed to charge at a constant current or a quasi-constant current. The standard charging current of a general-purpose storage battery is 0.1 C (hour rate), and it takes 14 to 16 hours to fully charge the battery. Therefore, there is a great demand for a battery that can be charged in a shorter time and a charge control method, and some charging devices that can perform rapid charging for about 1 hour have been developed.

The rapid charge control system is a battery voltage detection system,
A -ΔV detection control method, a battery temperature detection method, a timer method, etc. are known. Among them, the timer method of charging for a certain time by a timer is the simplest in terms of circuit, and can be commercialized at a cost close to that of a general slow-speed charging device. However, in the case of a timer-type rapid charging device, care must be taken because a battery with a remaining capacity will be overcharged. As is well known, overcharging causes the life of nickel-cadmium storage batteries to be shortened. Therefore, it is not possible to easily use the timer-type rapid charging device unlike the general slow speed charging device.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to use a timer-controlled charging circuit having a simple structure, and to always charge properly regardless of the remaining capacity of the battery. An object of the present invention is to provide a charging device for a nickel-cadmium storage battery that can be performed.

[0006]

The charging device of the present invention comprises:
A discharge circuit for discharging the nickel-cadmium storage battery set in the battery mounting portion, a timer-type charging circuit for charging the storage battery for a certain period of time, and the discharge circuit is first connected to the discharge circuit for discharging. And a control circuit that disconnects the discharge circuit from the storage battery and connects the charging circuit to the storage battery to activate the discharge circuit when the discharge current becomes lower than a reference value.

[0007]

When the nickel-cadmium storage battery is set in the battery mounting portion of the charging device, the discharge circuit is first connected to the storage battery, and the remaining capacity is discharged. When the discharge current due to the remaining capacity becomes lower than the reference, the control circuit operates, the discharge circuit is disconnected from the storage battery, and at the same time, the charging circuit is connected to the storage battery and activated. That is, the battery is discharged to the reference state regardless of the remaining capacity, and then the timer type charging circuit charges the battery for a fixed time.

[0008]

FIG. 1 shows the circuit configuration of a charging device according to an embodiment of the present invention. In the figure, reference numeral 1 indicates a nickel-cadmium storage battery set in the battery mounting portion. This charging device includes a discharging circuit 2 for discharging the storage battery 1 and a timer-type charging circuit 3 for charging the storage battery 1 with an output of an AC-DC converter 4 for a predetermined time.
And a control circuit for switching the operation sequence from discharging to charging.

After the storage battery 1 to be charged is set in the battery mounting portion, the self-reset type push button switch (normally open contact) 10 is operated to be temporarily turned on. Switch 10
When is turned on, the discharge circuit 2 is connected to the storage battery 1. The discharge circuit 2 includes a relay coil 6 and a discharge resistor R2.
And a parallel circuit of a display circuit (current limiting resistor R1 and LED lamp 5). When the switch 10 is turned on, the relay coil 6 is excited by the remaining capacity of the storage battery 1, and the relay contacts 6a and 6b are inverted. That is, the normally closed contact 6b is turned off and the normally open contact 6a is turned on. When the relay contact 6b is turned off, the output of the AC-DC converter 4 becomes the charging circuit 3
When the storage battery 1 has a remaining capacity although it is not supplied to the discharge circuit 2, the discharge current of the storage battery 1 continues to flow in the relay coil 6, and the state is maintained by turning on the relay contact 6a.

Therefore, when the storage battery 1 has a certain amount of remaining capacity, even if the push button switch 10 is released and the finger is turned off, the discharge current of the storage battery 1 causes the relay 6 to self-hold and continue discharging. The discharge current of the storage battery 1 also flows into the LED lamp 5 to light it. Storage battery 1
The discharge voltage decreases as the discharge progresses. When the discharge current becomes smaller than the value required for self-holding of the relay 6, the relay contact 6a returns to OFF and the discharge circuit 2 is disconnected from the storage battery 1, and at the same time the relay contact 6b returns to ON and A
The output of the C-DC converter 4 is supplied to the timer type charging circuit 3, and the timer type charging circuit 3 is activated.

The timer type charging circuit 3 has a timer 9 and its timer contact 9a, and the normally closed timer contact 9a is turned off after a certain time (1 hour) after the timer 9 is energized. When the timer contact 9a is on, the DC output of the AC-DC converter 4 is supplied to the storage battery 1 via the relay contact 6b, the timer contact 9a, the current limiting resistor R4, and the backflow prevention diode 8, and the storage battery is quasi-constant current system. 1 is charged. At the same time, during charging, a current also flows through the LED lamp 7 through the current limiting resistor R3, and this lights up. Note that the LED lamp 5 for discharge display and the LED lamp 7 for charge display have different emission colors.

When a certain time has elapsed from the start of charging, the timer contact 9a turns off and the charging operation ends.

[0013]

As described in detail above, the charging device of the present invention first discharges the nickel-cadmium storage battery set in the battery mounting portion, and when the discharge current becomes less than the reference, the discharge circuit is Since the timer-type charging circuit is activated at the same time to charge the battery for a certain period of time at the same time, even if the remaining capacity of each storage battery is different, it will be charged for a certain period of time after the remaining capacity is discharged to almost zero. Since it is performed, there is no fear of overcharging, and all batteries can be charged in appropriate amounts. Therefore, it is not necessary to carry out a troublesome operation such as charging up at an appropriate time while being aware of the remaining capacity. In addition, since there is no danger of overcharging, there is no problem even if quick charging is performed by the timer type charging circuit, and the inexpensive timer timer type rapid charging circuit allows even ordinary people who do not have electrical knowledge to charge with peace of mind. It can be carried out.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a charging device for a nickel-cadmium storage battery according to an embodiment of the present invention.

[Explanation of symbols]

 1 Nickel-cadmium storage battery 2 Discharge circuit 3 Timer type charging circuit 4 AC-DC converter 5 LED lamp 6 Relay coil 6a, 6b Relay contact 7 LED lamp 8 Diode 9 Timer 9a Timer contact 10 Pushbutton switches R1 to R4 Resistance

Claims (1)

[Claims] 1. A discharge circuit for discharging a nickel-cadmium storage battery set in a battery mounting part, a timer type charging circuit for charging the storage battery for a predetermined time, and the discharge circuit is first connected to the storage battery. And discharging, and disconnecting the discharge circuit from the storage battery when the discharge current becomes equal to or less than a reference, and a control circuit for connecting the charging circuit to the storage battery and activating the nickel. -Cadmium battery charger.