JPS6022775Y2 - battery charging device - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a device for charging two or more batteries in parallel.

Conventionally, a common switch is inserted between two or more batteries, a parallel circuit, and a charging power source, but in order to prevent overcharging, the battery charging voltage is detected based on the battery that initially has a large remaining capacity. However, when charging is stopped by turning off the common switch section, batteries with low remaining capacity are not sufficiently charged.

Conversely, when the battery charging voltage is detected based on a battery with a small remaining capacity, the battery with a large remaining capacity will be overcharged.

Furthermore, when detecting the charging voltage of the battery when a charging current is flowing in, the voltage drop due to the charging current and the internal impedance of the battery is also taken into consideration, resulting in erroneous detection.

The present invention has been devised in view of these points, and each embodiment of the present invention will be described below with reference to the drawings.

First, to explain the first embodiment, in FIG. 1, two batteries 2 and 3 are connected in parallel to a charging power source 1, and gate turn-off type silicon controlled rectifiers are connected in series with each battery as semiconductor switch elements ( (hereinafter referred to as SCR) 4,
5 to form each charging path.

Reference numeral 6 denotes a pulse generating circuit which generates a repetitive pulse signal for forming an on period and an off period of each SCR by shifting the phase according to each SCR.

This pulse generating circuit 6 consists of a pulse generator 7 and a counter 8. As shown in FIG. 2, the outputs of the counter 8 are as shown in b and C in response to the pulse a1 from the pulse generator 7. Focusing on this output C, Then, the rising signal d of the output C
1 becomes the turn-on signal of 5CR4, and the falling signal of the output C becomes the turn-on signal.

Therefore, for one SCR4, period T1 in the figure is an on period, and T
2 is an off period, and for the other 5CR5, T1 is an off period and T2 is an on period.

The batteries 2 and 3 are charged during this on period.

Next, 9 is a detection control circuit which detects a predetermined battery charging voltage during the OFF period of each SCR and individually maintains each SCR OFF using the detection output. Multiplexer 1
Consists of 2.

Then, during the ON period T1 or T2 of -f3cR4,5, this SCR becomes conductive and charges the battery 2 or 3.

Therefore, batteries 2 and 3 are gradually charged. The battery 2 is charged during the period T1 of the counter output C, but the falling signal turns off the SCR 4.

Therefore, the period T2 becomes a charging stop period, and the charging voltage of the battery 2 is compared with a predetermined reference voltage in the detection circuit 11 through the multiplexer 10, and when the charging voltage has not yet reached the predetermined voltage, a demultiplexer synchronized with the multiplexer 10 is used. There is no detection output through 12 as in the second group, and the next rising signal d1 causes SCR4 to be output again.
turns on and charges battery 2.

On the other hand, when the charging voltage of the battery 2 when 5CR4 is off is higher than the predetermined voltage, the output of the detection circuit 11 from the demultiplexer 12 appears as shown in e2 of FIG. 2, and the subsequent rising signal d□ is bypassed. This prevents the hip 5CR4 from turning on and maintains this SCR in the off state.

Similarly, when the charging voltage of the other battery 3 when the SCR 5 is off is equal to or higher than a predetermined voltage, further charging is stopped.

FIG. 3 shows the second embodiment.The difference from the first embodiment will be explained in that transistors 13 and 14 are used as semiconductor switch elements connected in series to each battery 2 and 3.

Further, the pulse generation circuit 6 includes a pulse generator 7 and a counter 8.
As shown in FIG. 4, in response to pulse a2 from pulse generator 7, a pair of counter outputs (i) and (c) are obtained, and the OR circuit 15 receives signals a2 and b as inputs. The output becomes f, which is applied to the base of one transistor 13.

Similarly, the output of the OR circuit 16 which inputs the signal a2 and C becomes g, which is applied to the base of the other transistor 14.

The output f becomes a repetitive pulse signal during the on period and off period of both transistors 13 and 14, respectively.

Since it is determined by g, the phase is shifted.

Furthermore, the detection control circuit 9 detects that the output f9g is connected to the inverter 1.
a gate circuit 19.20 applied via 7.18;
Detection circuits 11A and 11 to which charging voltages of the batteries 2 and 3 are applied via this gate circuit and compared with a predetermined reference voltage.
B and the output of this detection circuit is inverted and the output L g
The flip-flops 21 and 22 block the voltage from being applied to the bases of the transistors 13 and 14.

In the above configuration, each battery 2,
3 is charged.

During the off period T3 of one output f, the gate circuit 19 is opened by the inverter 17, and the charging voltage of the battery 2 is detected by the detection circuit 1.
1A, and when the charging voltage or predetermined voltage has not been reached, the flip-flop 21 is not inverted, and the battery 2 is charged again after the off period "3" has elapsed.

On the other hand, when the battery charging voltage during the off period T3 reaches a predetermined voltage or higher, the flip-flop 21 is inverted.

Therefore, after the off period T3 has elapsed, the output amount f will not bypass through the flip-flop 21 and the transistor 13 will not become conductive.

Therefore, transistor 13 is maintained in an off state, and battery 2
Charging will be stopped.

Similarly, when the charging voltage of the transistor 14 when the transistor 14 is off is equal to or higher than a predetermined voltage, charging of the other batteries 3 is stopped thereafter.

FIG. 5 shows a modification of the second embodiment, which differs from the detection control circuit 9 in the ant circuit 23.
4 and a common detection circuit 11, and a latch circuit 25 is provided in place of the flip-flops 21 and 22.

As shown in FIG. 6, the pulse a2 from the pulse generator 7
, a pair of counter outputs s and c are obtained, and the signals a2 . The output of the OR circuit 15 with input b becomes f, and this output f and one output of the latch circuit 25 become the inputs of the AND circuit 23, and its output i becomes the output of the transistor 13.
is applied to

Similarly, signal a2. The output of the OR circuit 16 inputting c is g, and this output g and the other output j of the latch circuit 25
becomes an input of the AND circuit 24, and its output k is applied to the transistor 14.

Therefore, when the transistor 13 is turned off at time t1, the charging voltage of the battery 2 is changed to the gate circuit 19 as in the second embodiment.
is applied to the detection circuit 11 through the battery charge voltage and compared with a predetermined reference voltage, and when the battery charging voltage has not reached the predetermined reference voltage, there is no change in the latch output, and at time t2 when the AND output i reaches 1 Battery 2 is charged.

Next, when the transistor 13 is turned off, if the battery charging voltage is higher than the predetermined reference voltage, it is latched at the AND output i, and the latch output changes from "1" to "O".
After that, the AND output i is maintained at 0.

Therefore, transistor 13 is kept off and charging of battery 2 is stopped.

Similarly, when the charging voltage of the transistor 14 when the transistor 14 is off is equal to or higher than the predetermined reference voltage, charging of the other batteries 3 is stopped thereafter.

When this is the case, further charging is stopped.

In each embodiment, in order to simplify the explanation, a case has been described in which two batteries are connected in parallel to a charging power source, but it is clear that the number of batteries connected in parallel can be two or more. It is.

As described above, according to the configuration of the present invention, a plurality of batteries connected in parallel to a charging power source can be individually charged to a predetermined charging voltage. This eliminates the drawback that some batteries may be overcharged or undercharged, such as in a device.

Further, a pulse generating circuit is provided which alternately generates a repetitive pulse signal for forming the on period and off period of the semiconductor switch elements connected in series to each battery at a time interval of 172 cycles to each switch element. and detecting a charging voltage of a battery connected to one of the switch elements that is in an off state, and when the detected voltage is equal to or higher than a predetermined voltage, the switch element that is in an off state is maintained in an off state. Since the control circuit is provided, the state of charge of each battery can be detected at different times, and although the detection circuit section for the state of charge may be provided separately, the configuration is simple and inexpensive if one unit is used in common. become,
Furthermore, since the battery charging voltage is detected during the off period, that is, when the battery is not being charged, it has excellent effects such as being able to detect the correct battery charging voltage excluding the voltage drop caused by the internal impedance of the battery.

[Brief explanation of the drawing]

1, 3 and 5 are electrical circuit diagrams showing different embodiments of the charging device according to the present invention, and FIGS. 2, 4 and 6
The figures are waveform explanatory diagrams etc. in each example. 1... Charging power source, 2, 3... Battery, 4
．． 5. 13.14...Semiconductor switch element, 6...Pulse generation circuit, 9...Detection control circuit.

Claims (1)

[Scope of utility model registration request] A battery group consisting of a pair of at least one battery connected in parallel to each other to a charging power source, a semiconductor switch element connected in series to each battery group, and for forming an on period and an off period of each of the switch elements. A pulse generation circuit that alternately generates a repetitive pulse signal of 1 to each switch element at a time interval of 172 cycles, and a charging voltage of a battery connected to one of the switch elements that is in an OFF state. A battery charging device comprising a detection control circuit that detects and maintains the off-state switch element in the off-state when the detected voltage is equal to or higher than a predetermined voltage.