JPS6311031A - Charge controller of secondary 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 Field of Industrial Application The present invention relates to a charging control device for a secondary battery built into a rechargeable vacuum cleaner or the like used in general households.

BACKGROUND OF THE INVENTION The structure of a conventional charging control device will be described below with reference to the drawings. In FIG. 3, 1 is a transformer of the DC power supply device 4, and 2
．． 3 is a rectifying diode.

A secondary battery 5 and a switching element (transistor in this embodiment) 6 are connected in series to the DC power supply device 4. The pace terminal of transistor 6 is connected to resistor 7. It is connected to the positive electrode of the DC power supply device 4 via a diode 8 . Further, a thyristor 9 is connected between the anode of the diode 8 and GND, and the gate terminal of the thyristor 9 is connected to the connection point between the Zener diode 10 and the resistor 11.

The other end of the resistor 11 is connected to (rND) of the DC power supply 4, and the other end of the Zener diode 10 is connected to the positive electrode.The capacitor 12 is for smoothing the DC power supply 4.

Charging of the secondary battery 5 is performed by resistor 7.
A current is supplied to the base of the transistor 6 via the diode 8, the transistor 6 is turned on, and a charging current is supplied to the secondary battery 5. When the voltage between the terminals of the secondary battery increases with charging and reaches the Zener voltage of the Zener diode 10, a gate current is supplied to the thyristor 9 via the Zener diode 10, and the thyristor 9 is turned on. At this point, the pace current of transistor 6 is cut off and charging is stopped.

FIG. 5C&) shows charging characteristics when charging is performed using the above-mentioned conventional charging control device.

In the figure, 13 is a charging voltage, and 14 is a charging current.

Further, 15 is a charging completion voltage set by the Zener diode 1o.

Problems to be Solved by the Invention However, the conventional charging control device described above has a problem in that charging is interrupted immediately after charging starts depending on the state of the secondary battery (over-discharged or over-charged state). It was something. As shown in Fig. 4, the cause of this is that the secondary battery 5 is equivalent to a series circuit of a voltage source (EQ) 16 according to the remaining capacity and an internal resistance (r) 17, and overdischarge is taken as an example. The remaining capacity is small, the voltage Eo becomes low, and the internal resistance 17 becomes large. When such a secondary battery 5 is charged with a full-wave rectified charging current, the voltage vo between the terminals of the battery is expressed as 'I10 = Eo + I・r, and since the internal resistance r is large, the voltage occurs, and the height of this voltage peak increases in proportion to the internal resistance r. Then, although Eo is low, the peak value of the voltage exceeds the charging completion voltage 18 at the beginning of charging, so the thyristor 9 is turned on and the charging current is cut off.

As described above, conventional charging control devices have a problem in that they cannot be charged when a battery has been overcharged or overdischarged.

FIG. 5(b) shows the charging characteristics at this time, where 19 indicates the charging voltage, 20 indicates the charging current, and 21 indicates the charging completion voltage.

The present invention aims to solve the above-mentioned conventional problems, and is configured so that even if the secondary battery itself is in an over-discharge state, charging can be performed until charging is completely completed, thereby improving the reliability of the charging control device. It is intended to improve

Means for Solving the Problems In order to solve the above conventional problems, the present invention provides a series circuit of a secondary battery and a switching circuit connected to the output of a full-wave rectified DC power supply, and a series circuit of a switching circuit connected to the output of a full-wave rectified DC power supply. It has a synchronous pulse generation circuit that generates a pulse train synchronized with seven crosses of a full-wave rectified voltage waveform, a secondary battery voltage detection circuit, and a latch circuit, and generates a voltage in synchronization with the pulse signal from the synchronous pulse generation circuit. When the detection circuit is activated and the terminal voltage of the secondary battery reaches an externally determined voltage, a signal is generated from the voltage detection circuit,
The above switching circuit is cut off via a latch circuit,
It is configured to stop charging.

Effect: In the above configuration, the voltage detection circuit operates at the timing when a synchronous pulse synchronized with the full-wave rectified waveform of the DC power supply is generated, so the voltage vo between the terminals of the battery is vo = xo + IXr (see Figure 4). ), the EQ in the above equation means that only the normal battery voltage is detected. As described above, the charging control device according to the present invention enables charging control that is completely unaffected by the internal resistance of the battery.

Example Examples thereof will be described below based on the drawings.

In FIG. 1, 101 is a DC power supply device, and a full-wave rectified voltage is generated at the output A (the voltage waveform is shown in FIG. 2 (2L)).

Further, a secondary battery 102 and a first switching circuit 103 are connected in series between the output terminals of the DC power supply 101, and charge is performed when the first switching circuit 103 is in the ON state, and stops charging when the first switching circuit 103 is in the OFF state. This is how it works. 104 is a synchronous pulse generation circuit connected between the output terminals of the DC power supply 101 and synchronized with the full-wave rectified voltage waveform, and its output waveform B is shown in FIG. 2(b). 0 again
The waveform at the point is the rectifier diode 105 and the DC power supply 101.
Since the output of the secondary battery 102 and the charging control circuit side of the secondary battery 102 are separated, as shown in FIG. 2(C), the output of the secondary battery 102
A voltage is generated that is represented by the sum of the remaining capacity EO, the charging current, and the voltage having a peak value proportional to the internal resistance of the secondary battery 102. 106 is a voltage detection circuit υ, which operates only when the second switching circuit 107 receiving the output signal of the synchronous pulse generation circuit 104 is in the ON state, and the voltage detection circuit 106 does not operate while no pulse is generated. Become. Therefore, since the synchronous pulse is generated at the zero-crossing part of the full-wave rectified waveform, the voltage detection circuit works only when the voltage Eo in Figure 2 (C) is generated, and only the normal voltage XO is detected, and the internal resistance It becomes possible to detect voltage completely unaffected by r. Here, the voltage detection circuit 106 calculates the battery voltage (
(in this case, the voltage is proportional to EO) reaches a predetermined charging completion voltage, the output signal is input to the latch circuit 10B, and the first switching circuit 103 changes from ON to OFF state, and the OFF state is maintained by the latch circuit 108. Therefore, charging will be stopped.

According to the above configuration, charging of the secondary battery 102 is not affected by the internal resistance r at all, so the secondary battery 102
Even if 2 is overcharged or overdischarged and has a high internal resistance, it does not affect charging at all, and the normal voltage T! , o are charged without malfunction until they reach a predetermined voltage. Therefore, the conventional problem that the charging control device malfunctions when the internal resistance r of the secondary battery 102 becomes high can be solved.

Effects of the Invention As described above, according to the present invention, since the voltage detection circuit is operated by a synchronized pulse synchronized with the full-wave rectified waveform of the DC power supply, the voltage detection circuit detects only the normal voltage EO, which is caused by the internal resistance r. Since it is not affected at all, even if the secondary battery is overcharged or overdischarged, it will continue to be charged without malfunction until charging is completely completed. Furthermore, when performing rapid charging in the future, the influence of the internal resistance r has been a major obstacle, but this will all be solved by fully adopting the system of the present invention. Furthermore, the use of the device of the present invention will significantly reduce the number of complaints about battery defects that have arisen due to malfunctions of conventional charging control devices, resulting in a significant improvement in market quality.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a charging control device showing an embodiment of the present invention, Fig. 2 (&), (b), and (0) are waveform diagrams of the charging control device, and Fig. 3 is a conventional charging control device. circuit diagram,
FIG. 4 is an action explanatory diagram, and FIGS. 5 (iL) and (b) are charging waveform diagrams. 101...DC power supply device, 103...
Switching circuit, 104... Synchronous pulse generation circuit, 106... Battery voltage detection circuit, 108.
...Latch circuit. Name of agent: Patent attorney Toshio Nakao and 1 other personE〇-Battery level! 4t r----Content of 15 J1! ,) Maru! ---Katsu Den Den; Circle Figure 2 Vo-Eo+I+cr OL U'' Figure 5 Time Time

Claims (1)

[Claims] a series circuit of a secondary battery and a switching circuit connected to the output of the full-wave rectified DC power supply; a synchronous pulse generation circuit that generates a pulse train synchronized with the zero cross of the full-wave rectified voltage waveform of the DC power supply; A secondary battery voltage detection circuit,
a latch circuit, the voltage detection circuit is operated in synchronization with the pulse signal from the synchronous pulse generation circuit, and when the terminal voltage of the secondary battery reaches a predetermined voltage, the voltage detection circuit generates a signal; A charging control device for a secondary battery configured to shut off the switching circuit via a latch circuit to stop charging.