JPS5854839A - Charge control circuit for storage battery - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a storage battery charger used by being inserted into a power tool, and particularly to a charging control circuit thereof.

In recent years, with the penetration of convenient cordless power tools powered by storage batteries into the market, opportunities to use chargers have increased, and with this, problems with the charging performance of chargers have become a problem. Taking up this problem, the gate circuit of switching elements such as thyristors detects the heat generation of the storage battery at the end of charging.

City 1] For those that control the charging operation to stop (
1) When the source pressure is high or the temperature is high, the charging current of the storage battery passes through the temperature sensor, which causes the temperature sensor to self-heat and reach the operating temperature. However, charging operation stops.

(2) In devices that use a temperature detection switch as a temperature sensor, arcing caused by switching on and off the charging current can cause welding of the contacts, overcharging the storage battery, and causing damage and burnout of the storage battery. This significantly shortens the life of the temperature detection switch contacts.

(6) If you continue to connect the charger to the power outlet after the storage battery is fully charged, the charging operation will be restarted due to sudden fluctuations in the power supply voltage, and the storage battery will be overcharged (
Similar to 2), the storage battery breaks down.

(4) When the source acid pressure is low or the temperature is low,
Charging operation cannot be started.

(5) Depending on the charger and storage battery, the amount of drowsiness during charging when the charging operation is stopped varies, and charging is not performed consistently.

etc., there was a drawback that satisfactory charging characteristics could not be obtained.

As a result of the inventor's analysis of the causes of these problems, the conventional charger in this building had problems with the control status of the thyristor gate that restricts charging, the connection position and operation of the temperature detector in the circuit. It turns out that there is.

It is an object of the present invention to eliminate the drawbacks found in the conventional chargers described above, and to ensure that switching elements such as thyristors are gated and gated during charging operation, regardless of fluctuations in source pressure and temperature. It triggers the operation state to continue, and when the storage battery reaches full charge, it accurately detects this and stops the charging operation, ensuring that the switching element is not activated during subsequent non-charging operations of the charger. In short,
To provide a charging control circuit that can perform reliable and efficient charging under any charging conditions.

The present invention provides a control circuit for a charger that lights up when a storage battery container is inserted into a charger and is equipped with a temperature detection switch that is disposed in close contact with the storage battery body and detects heat generation when the Wakasa Pond is full. In this case, the AC power source is '+' l fR and the storage battery is connected to the smooth (-) current supply source via a thyristor that controls the charging operation, and the gate of the thyristor and one end of the storage battery are connected to the temperature sensor. A switch is used to connect the thyristor gate, and a capacitor and a resistor connected in parallel to each other are connected in a 1h series to the thyristor gate, and in the non-charging operation state after charging is completed, the thyristor gate is short-circuited to close the gate. It is equipped with a transistor that bypasses the current, and enables reliable and complete nine-ridge control.

Specific embodiments of the present invention will be described with reference to the drawings. 1st
The figure is an electric circuit diagram according to the present invention. In the figure, 1 is an AC open circuit, 2 is a transformer that performs insulation and step-down, and 3 is a transformer 2.
4 is a full-wave rectifier connected to the output terminal of the transformer, and 5 is a current fuse that prevents overcurrent from flowing into the charging circuit.

6 is a storage battery, and 7 is a switching element such as a thyristor (hereinafter referred to as a thyristor) for controlling charging of the storage battery 6. These are connected in series with each other, and both ends thereof are connected in parallel to the rectified output terminal of the full-wave rectifier 4. Ru. 8 is full wave rectifier 4
A smoothing capacitor for stabilizing operation is connected in parallel with the rectified output terminal VC of the capacitor 8, and 9 is a resistor for discharging the capacitor 8.

10.11.12 are each i connected in series with each other
These are a t-detection switch, a diode, and a temperature fuse, and are connected between the θ terminal of the storage battery 6 and the gate of the thyristor 7. The temperature detection switch 10 is disposed in close contact with the surface of the case of the storage battery 6, and detects the temperature of the surface of the storage battery 6. The contact is closed during charging operation and supplies gate current to thyristor 7, and when the storage battery 6 heats up at the end of charging, it becomes open at a temperature corresponding to the full state, and then returns to the open state due to natural cooling when charging is stopped. An operation is performed to return to the closed state, and in this process, the gate circuit of the thyristor 7 is temporarily opened. The warm fuse 12 is activated when the temperature of the storage ff pond 6 rises by 1j due to a malfunction of the charging section 6 or the like.

Reference numeral 13 indicates a circuit section included in the storage battery container, and the charging control circuit 14 is electrically connected to the section indicated by a-a', bb', and c-c' through connectors, etc. I'm starting to get it. Note that the diode 11 is provided to prevent the storage battery 6 from being short-circuited by accidentally contacting the a' and b' ends when the storage battery container is disconnected from the charger and damaging the temperature detection switch 10. It is provided for. 15 is a resistor for limiting the gate current of thyristor 7, and 16 and 17 are connected in parallel to each other to connect the gate of thyristor 7 and resistor 1.
It is a capacitor and a resistor installed between 50 and 50, and is configured to supply a strong current during light-duty operation, and suppress the current to a very small amount during non-charging operation.

18 and 19 are resistors and capacitors connected in parallel between the gate and cathode of the thyristor 7 to absorb gate noise.

20 and 21 are resistors and capacitors connected in series with each other to form an integrating circuit, one end of which is connected to the cathode of the thyristor 7, and the other end connected to the θ terminal of the storage battery 6.
It is continued. Note that diodes 22 and 23 are connected in parallel to the resistor 20 and the capacitor 21, respectively, in a direction opposite to the charging polarity of the capacitor 21.

24 is a switching element (hereinafter referred to as a transistor) such as a transistor that shorts the gate and cathode of the thyristor 7 and bypasses the current flowing to the gate circuit of the thyristor 7 when the charger is in non-charging operation; 24 paces, 20 resistors, 21 capacitors
A Zener diode 25 is connected between the connection points.

26 is a resistor connected in parallel between the pace and emitter of the transistor 24. 27 is a diode provided between the collector of the transistor 24 and the gate of the thyristor 7, and due to the voltage drop in the 110 direction of the diode 27, when the transistor 24 is in a conductive state, the emitter-collector saturation due to an increase in the collector magnetic current, vOm. Even if the pressure rises, the HC4 flow of the thyristor 7 is prevented from flowing into the thyristor 7.

28 is a pilot lamp consisting of a light emitting diode, etc., which indicates that charging is in progress; lI
The control is performed by the voltage generated between the gate and cathode when the thyristor 7 is in a conductive state.

29 is a transistor for driving the pilot lamp 28, 30 is a current limiting resistor, and 31 is a resistor provided between the pace of the transistor 29 and the gate of the thyristor 7.

The operation of the charging circuit configured as described above will be explained with reference to the timing chart shown in FIG.
1. When the storage circuit 13 is connected to the photoelectric control circuit 14, current flows through the route of the transformer 2, all-V rectifier 4, storage battery 6, and thyristor 7, and charging of the storage battery B is started.

During the charging operation, the thyristor 7 is gate-triggered every half cycle of the magnetic source 1, and continues a switching operation having two states of conduction and non-conduction within a half cycle.

A capacitor is connected to the gate of the thyristor 7 via a warm detection switch 10, a diode 11, etc. from the point at which the output voltage of the full-wave rectifier 4 becomes higher than the terminal voltage of the storage battery 6 at the beginning of a half cycle. Gate current begins to flow through 16. When the gate current reaches the gate trigger current value of the thyristor 7, the thyristor 7 is turned on, becomes conductive, and the storage battery 6 is charged. While the thyristor 7 is conducting, the pilot lamp 28 lights up. A strong gate current is supplied to the thyristor 7 by the capacitor 16, and the capacitor 16 repeatedly charges and releases in response to the switching operation of the thyristor 7. That is, charging is performed by the above-mentioned gate current, and discharging is performed during the period from when the thyristor 7 is turned on until the gate current begins to flow through the thyristor 7 in the next half cycle, and the charged charge is transferred to the resistor 17. is discharged.

At the end of the half cycle of the AC radio wave 1, when the output voltage of the full-wave light generator 4 becomes lower than the terminal voltage of the storage battery 6, the anode current of the thyristor 7 becomes less than the holding current, and the thyristor 7 is turned off.

As charging progresses as described above and the storage battery 6 reaches the final stage of charging, the temperature on the surface of the storage battery 6 will rapidly increase as charging progresses due to the internal resistance of the storage battery 6 and heat generated by the gas reaction inside the battery. Rise.

The warm detection switch 10 opens the contact at a temperature corresponding to full charge (for example, 45°C), and the previously closed state is reversed to the open state, and the gate circuit of the thyristor 7 is opened to start charging. stops.

When the light beam stops, the capacitor 21 starts to become magneto-magnetic, the charged acid pressure rises, and the Zener dial 1--25 starts charging and transmitting pressure.
When the Zener withstand voltage reaches the Zener breakdown voltage, a base magnetic current flows through the transistor 24 and the transistor 24 becomes conductive, shorting the gate and cand of the thyristor 7 and preventing the thyristor 7 from being turned on thereafter. Due to the conduction of the transistor 24, the contact of the temperature detection stopper 10 is reversed due to the cooling of the storage battery 6 after the charging operation is stopped, and the contact of the temperature detection switch 10 is again closed, and even if the current flows due to the opening of the gate circuit of the thyristor 7,
A current is bypassed to the collector side of the transistor 24, and no current flows to the gate of the thyristor 7, so that a non-conductive state is maintained. Note that after the temperature detection switch 10 is closed, the capacitor 6 remains charged, and the bypass current of the transistor 24 becomes minute, flowing through the resistor 17.

) In FIG. 1 showing a specific embodiment of the present invention, the transistor 24 is used as the element that shorts between the gate and cathode of the thyristor 7, but the present invention is not limited to this, and a switching element such as a thyristor may be used. etc. may also be used.

According to the present invention, the temperature detection switch 10 is connected to the thyristor 7.
Since the charging current of the storage battery B does not pass through the temperature detection switch 10, self-heating of the warm detection switch 10 does not occur, and the power supply voltage is
Even when the temperature is low or the temperature is good, complete charging can be performed, and since there is no opening/closing operation of the charging current, there is no overcharging of the t11I6 due to welding of the contacts, and at the same time there is no wear of the contacts (f- can be prevented and extend its life.

According to the present invention, after the charging operation is stopped, the transistor 24 short-circuits the gate of the thyristor 7.
Since there is no gate current flowing to the supply voltage ! 4
! Even if current flows through the gate circuit of the thyristor due to drastic fluctuations, the thyristor 7 will not be gate-triggered, and overcharging of the storage battery 6 due to old charging operation can be prevented.

Further, the control signal for the pilot lamp 28 can be obtained from the direct pressure generated between the gate and cand of the thyristor 7, and the number of parts of the indicator lamp circuit can be reduced.

According to the present invention, since the gate of the thyristor is short-circuited during non-charging operation, the values of the capacitor and resistor connected in series with the gate circuit can be freely selected and a strong gas is applied to the thyristor 7 during the charging operation. Since t&ci can be supplied, the charging operation can be reliably started even when the power supply voltage is low or the temperature is low and the gate trigger sensitivity of the thyristor 7 is poor.

According to the present invention, the heat generated by the fully charged battery 6 is detected by the operation of the contact of the temperature detection switch 10 from closing to opening, and the gate circuit of the thyristor 7 is opened, so that the thermistor etc. The temperature change in the resistance value of the thyristor 7 is used for operation, and the gate current is not controlled by the impedance change rC of the gate circuit. It can be stopped and always charged with a constant amount of electricity.

According to the invention, one end of the temperature detection switch 10 can be connected to the θ terminal of the storage battery 10, thereby saving the number of connectors for electrically connecting the charging control circuit 14 and the storage battery container internal circuit 13. This reduces costs and improves reliability.

[Brief explanation of the drawing]

FIG. 1 is a one-shot circuit diagram showing a specific embodiment of the present invention, and FIG. 2 is a timing chart schematically showing the operation of the one-shot circuit of FIG. 1. In the figure, 1 is an AC core source, 4 is a full-wave rectifier, 6 is a reservoir, 7 is a thyristor, 10 is a temperature detection switch, 16 is a capacitor, 17 is a resistor, and 24 is a transistor.

Claims (1)

[Claims] A storage battery connected to a father current power supply via a rectifier and a switching element such as a thyristor for controlling charging of the storage battery, which is connected to the output terminal of the storage battery and is connected to the output terminal of the storage battery when it is fully charged. a temperature detection switch that detects heat generation; a capacitor and a resistor that are connected between the heating switch and the gate of the switching element; and a temperature detection switch that detects heat generation of the switching element; A battery charging control circuit characterized by comprising a switching element that short-circuits the battery.