JPS6116763Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a battery charging device that charges m batteries to a predetermined state of charge.

A parallel charging method and a series charging method are known as methods for charging n batteries. The parallel charging method connects n batteries in parallel, but when charging from a commercial power source, for example, the voltage step-down rate must be increased in the step-down section, which has the disadvantage of large losses in the step-down section. The series charging method connects n batteries in series, and there is no need to increase the step-down ratio of the step-down section compared to the parallel charging method, and while there is less loss in the step-down section, the remaining capacity of each battery is reduced. If there is a difference, there is a drawback that some batteries may become overcharged or undercharged.

In view of these points, the present invention employs a series charging method, but attempts to eliminate the drawbacks of this method.One embodiment of the present invention will be described below with reference to the drawings. In the drawings, reference numeral 1 denotes a charging power source, which is composed of, for example, a rectifying and smoothing output circuit that steps down the voltage of a commercial power source.
A charging path L is connected to the charging power source 1, and a voltage terminal 2
has. The control unit 3 provided in the charging path L has a first Darlington-connected switch element as a switch element.
It consists of second transistors Q1 and Q2, a third transistor Q3 that controls the cutoff of the transistors, a fourth transistor Q4 that makes the charging current flowing in the charging path L a constant current, and resistors R1 and R2. Connected between collector and base. The resistor R2 is inserted in the charging path L, and the base-emitter of the fourth transistor Q4 whose collector is connected to the base of the second transistor Q2 is connected to the resistor R.
Connected to both ends of 2.

Although n batteries can be inserted in series in the charging path L, in the embodiment, five batteries B1 are inserted into the charging path L.
The case of ~B5 is shown. Each battery has a shorting branch l1-l5 consisting of resistors r1-r5 and a respective relay switch.
Connections can be switched between RY1 and RY5.

Next, D1 to D5 serve as detection units corresponding to the individual batteries B1 to B5, and are supplied with power from the voltage terminal 2. Each detection section has the same configuration, and the first detection section D1 will be explained. That is, between the power supply terminal 2 and the ground, there is a series circuit of a detection switch SW1 and a constant voltage element Z that closes when it detects that the corresponding battery B1 is inserted into the charging path L, and a series circuit between the battery B1 and the short circuit branch. A switching circuit 4 that switches and connects l1 and a third transistor Q3
A control circuit 5 for controlling the battery B1 is connected in parallel to the constant voltage element Z, and a charging indicator light 6 and a detection circuit 7 for detecting a predetermined state of charge of the battery B1 are connected in parallel to the constant voltage element Z. The switching circuit 4 consists of a series circuit of a fifth transistor Q51 and a relay coil RC1 that opens and closes the relay switch RY1.A constant voltage is applied to the base of the fifth transistor Q51 by a constant voltage element Z, and the relay is activated by excitation of the relay coil RC1. Switch RY1
is connected to the battery B1 side. The control circuit 5 is a resistor R
A constant voltage from a constant voltage element Z is applied to the base of the sixth transistor, and the collector of the sixth transistor is connected to the base of the third transistor Q3. The detection circuit 7 includes a heat-sensitive thyristor S1 that detects the temperature of the battery B1 in a predetermined state of charge, a detection temperature setting resistor R4 connected between the gate and anode of the thyristor, and a noise prevention capacitor C.
The anode and cathode of the heat-sensitive thyristor S1 are connected to both ends of the constant voltage element Z.

Thus, the heat-sensitive thyristor S1 is a thyristor that switches depending on the temperature. That is, when the temperature of the thyristor exceeds a set value, the thyristor switches from the off state to the on state, and once conductive, the conductive state is maintained until the main current flowing between the anode and cathode becomes equal to or less than the holding current. Further, the switch temperature can be set by changing the resistance value of the detection temperature setting resistor R4, and increasing the resistance value lowers the switch temperature.

The operation in the above configuration will be explained.

() First, if no battery is inserted into the charging path L, each detection part Dn (suffix n is 1 to 5
It is a general term for same as below. ) detection switch
Since both SWn detect that the battery is not inserted and open, the fifth and sixth transistor Q5
Since the collector voltage of the sixth transistor Q6n is high, the third transistor Q3 is conductive, and the first and second transistors Q1 and Q2 are in a cutoff state, and the charging path L is opened. .

() Next, when only one battery, say B1, is inserted into the charging path L, the detection switch SW1 closes due to the presence of the battery, and since the battery temperature is low at the beginning of charging, the detection circuit There is no output of 7. Therefore, the fifth and sixth transistor Q5
1, Q61 are both conductive, relay coil RC1
Due to the excitation of the relay switch RY1, the battery B1
to charge the battery B1. Detection part D
2 to D5, each relay switch RY2 to RY5 is connected to the short circuit branch line l2 to l5 side as in the case of () above, and these detection parts D2 to D5
The collector voltage of each of the fifth transistors tends to increase, but due to the conduction of the sixth transistor Q61 of the first detection section D1, the collector voltage of the third transistor Q3 increases.
base voltage is low, the third transistor is cut off, and the first and second transistors Q1 and Q2 are conductive.

By charging the battery B1, the battery enters a predetermined charging state, and when the battery temperature rises and the temperature of the heat-sensitive thyristor S1 reaches a set value determined by the detection temperature setting resistor R4, the thyristor becomes conductive. Therefore, the fifth and sixth transistor Q5
1, Q61 is cut off due to a drop in its base voltage,
The relay switch RY1 is connected to the short circuit branch l1 side, and the fifth transistor of each detection unit Dn is cut off, so that the third transistor Q3 becomes conductive due to the rise in its base voltage, and the first and second transistors Q1 and Q2 are cut off. Charging is completed.

() When two to five batteries are inserted into the charging path L, the remaining capacity of each battery differs, so the time at which charging of the batteries ends differs. In other words, a battery Bk (subscript k is a number from 1 to 5) with a large remaining capacity quickly reaches a predetermined state of charge, and the battery Bk has a large remaining capacity. , the relay switch RYk connected to the battery Bk side is switched to the short circuit branch lk side, and charging of the battery is completed. At this time, battery Bk with low remaining capacity
continues to be charged because it has not yet reached the predetermined state of charge. In this way, charging is completed in order from the battery with the highest remaining capacity, and the last battery
When Bk″ is in a charged state, charging of all batteries is completed in the same manner as explained in () above.

Although the detection circuit Dn detects the battery temperature in the embodiment, it is clear that it may also detect the battery voltage.

As described above, according to the present invention, since n batteries are connected in series and charged, the step-down ratio of the charging power supply section can be lowered compared to the parallel charging method, and the loss in the step-down section can be reduced. Can be done. In addition, since the predetermined state of charge of each battery is detected and charged individually, it is possible to detect the predetermined state of charge of all n batteries connected in series. will not become overcharged or undercharged. Furthermore, when detecting the battery temperature to detect the predetermined state of charge of the battery, the battery and each detection section can be insulated.

[Brief explanation of the drawing]

The drawing is an electrical circuit diagram showing an embodiment of the device according to the present invention. B1-B5...battery, l1-l5...short circuit branch, L...charging path, D1-D5...detection section, 7...
...Detection circuit, 4...Switching circuit, Q1, Q2...Switch element, 5...Control circuit, S1...Temperature detection element.

Claims (1)

[Claims for Utility Model Registration] (1) A battery comprising: m charging paths that can be arranged in series so that each battery can be connected to a short-circuit branch, and n detection units that detect a predetermined state of charge of the batteries. , each detection section includes a detection circuit that detects a predetermined state of charge of a corresponding battery, a switching circuit that switches and connects the battery and the short circuit branch using the output of the circuit, and a switching circuit that connects the battery and the short circuit branch via the output of the detection circuit to the charging path. A battery charging device comprising a control circuit for controlling an inserted switch element, and controlling the switch element to be cut off when there is no output signal from any of the control circuits of the respective detection sections. (2) The battery charging device according to claim 1, wherein the circuit for detecting a predetermined state of charge of the battery includes a temperature measuring element for detecting battery temperature.