JPH0435979B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a charger for storage batteries, and the present invention relates to a so-called peak voltage that controls the charging current when the charging voltage is lower than the peak value of the charging voltage of the storage battery to be charged. This paper relates to improvements in detection methods.

(Prior Art) There is a storage battery charging method called the so-called peak voltage detection method, which detects the peak point of the charging voltage that appears at the end of charging of a sealed storage battery based on the charging voltage that decreases thereafter, and controls the charging current to the storage battery. Proposed. (For example, Japanese Unexamined Patent Publication No. 54-162140) (Problems to be solved by the invention) This device can rapidly charge a storage battery to be charged with a relatively large charging current, and at the end of charging regardless of the temperature of the storage battery. Although it is possible to reliably detect and be practically effective, if the temperature range exceeds a specified value, e.g.
At temperatures above 50° C. or below a predetermined value, for example below 0° C., the charging current is large and therefore has various adverse effects on the storage battery, reducing its lifespan.

(Means for Solving the Problems) The present invention eliminates these conventional drawbacks and includes a means for detecting the storage battery or its surrounding temperature, so that when the temperature becomes above or below a predetermined value, the charging current to the storage battery is reduced. In addition, when the temperature returns to a predetermined range, the influence of the existing peak value detection means is eliminated by the delay circuit, so that rapid charging can be reliably returned.

(Embodiment) An embodiment of the present invention will be described in detail based on the drawings. Reference numeral 1 denotes a DC power supply unit, which includes, for example, a plug for connecting to a commercial AC, a transformer, and a rectifier connected to the secondary side of the transformer. 2 is a constant current circuit, which has two transistors Q1 and Q2 with a common collector.
and diodes D1, D2, etc. connected between the emitters and bases of the transistors Q1, Q2. Reference numeral 3 denotes a storage battery to be charged, such as a sealed nickel-cadmium storage battery, which is connected in series to the constant current circuit section via a diode D3, and is charged by controlling the charging current to a constant level in the constant current circuit section 2 by the DC power supply section 1. Ru. 4 is a peak voltage detection unit, which includes three resistors R1, which are connected in parallel with the storage battery 3 to be charged;
A series circuit consisting of R2, R3 and a Sienna diode ZD1, and three OP amplifiers IC1 and IC whose output ends are connected to the non-inverting input terminal (+) in sequence.
2, IC3, and a peak hold capacitor C1 connected to the output terminal of the first OP amplifier IC1.
The third OP amplifier IC3 is used as a comparator, and its inverting input terminal (-) is connected to the series circuit (A), and the non-inverting input terminal (+) of the first OP amplifier IC1 is connected in series. Detects the potential difference between the circuit and the connected point (b), and then connects the capacitor C.
By holding the potential at point (B) according to 1, when the voltage at point (A) is lower than the voltage at point (B) instantaneously before, that is, the voltage held in capacitor C1, the third
It outputs an output signal from the output terminal of the OP amplifier IC3. 5 is the temperature detection section with two comparators
It consists of IC4, IC5 and a thermistor TH, and the thermistor TH is provided in contact with or in close proximity to the storage battery 3 to be charged, and detects the temperature of the storage battery itself or its surroundings. Two comparators IC4 are installed at the midpoint of the series circuit of the thermistor TH and resistor R4.
The non-inverting terminal (+) and inverting input terminal (-) of IC5 are connected, and the other inverting input terminal (-) and non-inverting input terminal are connected in parallel to dividing resistors R5, R6, R7 and R8, respectively. ，
Connected to the midpoint between R9 and R10. The output terminals of each comparator IC4 and IC5 are made common,
An output signal is output from the output terminal based on the resistance value of the thermistor, which changes depending on the temperature. Reference numeral 6 denotes a control section which includes a thyristor THYI, a comparator IC6, etc., and the output terminal of the comparator IC6 is connected to the base of the transistor Q2 of the constant current circuit section 2.
The output terminal of the peak voltage detection section 4 is connected to the gate of the thyristor THYI via a diode D4. Furthermore, the output terminal of the temperature detection section 5 is connected to the inverting input terminal (-) of the comparator IC6, and the output terminal and the output terminal of the peak voltage detection section 4 are connected via a diode D5. D
6 is a diode connected between the inverting input terminal (-) of the comparator IC6 and the anode of the thyristor THYI. 7 is a delay circuit and is a siener diode.
ZD2 and capacitor C2, the output terminal of the peak voltage detection section 4 and the thyristor of the control section 6
A Sienna diode ZD2 is inserted in series and a capacitor C2 is inserted in parallel between the gates of THYI. 8 is a timer circuit section, which consists of a timer (MC14541B manufactured by Motorola), etc., and is a safety timer for controlling charging time and preventing overcharging in unexpected situations such as when the peak voltage detection section 4 etc. does not operate. The output terminal thereof is connected to the gate of the thyristor THYI of the control unit 6 via the diode D7, so that the charging current is controlled by the timer output.

In the figure, R11 to R23 represent resistors, and D8 to D10 represent diodes.

The charger configured in this way has a DC power supply section 1.
When turned on, transistors Q1 and Q2 become conductive and rapidly charge the storage battery 3 to be charged. During that time, the peak voltage detection unit 4 continuously measures the charging voltage of the storage battery 3 to be charged using a series circuit of resistors R1, R2, R3 connected in parallel to this and a siener diode ZD1, and the storage battery 3 to be charged is charged. When the charging voltage reaches its final stage and passes the peak point of the charging voltage, the voltage at point (a) of the series circuit described above drops from the voltage at point (b) instantaneously before, so a detection signal is output from the third OP amplifier IC3 and the delay circuit is activated. When the capacitor C2 of No. 7 is charged and the Siener potential exceeds that of the Siener diode ZD2, this is applied to the gate of the thyristor THYI of the control unit 6, and the thyristor THYI becomes conductive. When the potential of the comparator IC6 decreases, an output signal is generated from the output terminal of the comparator IC6, and the transistor Q2 of the constant current circuit section 2
Since the base potential of is increased, it becomes non-conductive, and the charging current to the storage battery 3 to be charged passes only through the transistor Q1, and the control is switched from rapid charging to trickle charging with a small current value, and the charging of the storage battery 3 to be charged is controlled safely. Well, it's complete. Peak voltage detection section 4
If the temperature of the charged storage battery or its surrounding temperature exceeds a predetermined value and becomes 50°C or higher or 0°C or lower before the operation of , the resistance value of the thermistor TH of the temperature detection section 5 changes to a smaller or larger value, so the comparator IC4 or IC5 changes. The input signal of is inverted,
Since the output signal from the output terminal changes from the H level to the L level signal, the comparator of the control section 6
The input of IC6 is inverted, and an output signal is output from the output terminal, and the transistor Q of the constant current circuit section 2 is similar to the above.
2 becomes non-conductive and the charging current is controlled. At this time, as the charging current decreases, the peak voltage detection section 4 operates and outputs an output signal, but the diode D
The signal flows into the comparator IC4 or IC5 via the circuit 5, and the cycler THYI of the control section 6 is not conductive. When the temperature returns to the predetermined value, the input signal of the comparator IC4 or IC5 of the temperature detection section 5 returns to the original value, and accordingly, the comparator IC6 of the control section 6 also returns to the original state, and control of the charging current is released, and the constant current circuit section The transistor Q2 of No. 2 becomes conductive, and the storage battery 3 to be charged is quickly charged again. During this time, there is a slight time delay until the output signal of the peak voltage detection section 4 stops, but the Zener diode ZD2
The delay circuit 7 consisting of the capacitor C2 and the capacitor C2 prevents the thyristor THYI of the control section 6 from becoming conductive and ensures a return to rapid charging. When the storage battery 3 to be charged reaches the final stage of charging, the peak voltage is detected and the charging current is controlled as described above. Furthermore, timer circuit section 8
When the set time of the timer elapses, quick charging is controlled regardless of the presence or absence of peak voltage detection. Note that when the detection signals of the temperature detection section 5 and the peak voltage detection section 4 are almost simultaneous, and the detection signal from the temperature detection section 5 is slightly earlier and then a predetermined detection signal is output from the peak voltage detection section 4, the temperature is determined to be a predetermined value. When the value is restored, the detection signal from the peak voltage detection section 4 does not stop, so the capacitor C2 of the delay circuit 7 is charged in the same manner as described above, and the charging current is controlled when the voltage reaches or exceeds the Zener potential of the Zener diode ZD2.

(Effects) As described above, according to the present invention, rapid charging can be performed safely and reliably within a predetermined temperature range at all times, and even if the temperature returns to the predetermined temperature range after deviating from the predetermined temperature range, rapid charging can be performed reliably without malfunction. It has the effect of being able to recover.

[Brief explanation of drawings]

The figure is a circuit diagram of one embodiment of the present invention. 1...DC power supply section, 2...Constant current circuit diagram, 3...
...Storage battery to be charged, 4...Peak voltage detection section, 5...
...Temperature detection unit, 6...Control unit, 7...Delay circuit,
8...Timer circuit section.

Claims (1)

[Claims] 1 Continuously measure the charging voltage of the storage battery to be charged,
a first detection means for detecting that the charging voltage has decreased from a peak value and outputting a detection signal; and a first detection means for detecting that the temperature of the storage battery to be charged or its surrounding temperature has become above or below a predetermined value and outputting a detection signal. A second detection means for outputting an output, and a charging current control means for reducing the charging current and switching to trickle charging according to a detection signal from either the first or second detection means, A storage battery charger configured to release control of the charging current by delaying a detection signal from a first detection means that continuously measures the charging voltage when the charging voltage returns to a predetermined value.