JPH0787679A - Charger - Google Patents

Abstract

(57) [Summary] [Objective] To provide a charging device capable of performing rapid charging for a short time by using a pulse voltage in a constant voltage region during charging. [Constitution] In charging a secondary battery B, after the voltage v of the secondary battery B reaches a predetermined voltage, in a charging device for charging with a constant charging voltage, the secondary battery B has a predetermined voltage. Comparator 4 for detecting the reaching and pulse voltage generator 5
After the voltage v of the secondary battery B reaches a predetermined voltage value, the output voltage of the pulse voltage generator 5 is superposed on the charging voltage for charging, or the charging voltage is changed to the pulse voltage generator 5.
The charging time was shortened by switching to the output voltage and charging.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant voltage charging type charging device such as a lithium-ion battery or a lead battery, and the charging time is greatly shortened by charging using a pulse voltage in a constant voltage region. The present invention relates to a charging device.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing a configuration example of a conventional constant voltage charging type charging device. As shown in the figure, the conventional charging device includes a controller 1, a controller 2, a comparator 3, a transistor Q1,
Switch SW1, resistors R1, R2, R3, input terminal T
1, T2, and output terminals T3 and T4.

The DC power source is input from the input terminal T1 to the terminal e (emitter) of the transistor Q1, and the transistor Q1
From the first terminal c (collector) to the output terminal T3 through the switch SW1, the charging current i is supplied to the secondary battery B. The resistor R3 is a low resistor for detecting the charging current i, and is connected in series with the secondary battery B through the output terminal T4 (r3 << r1, r2, where r1, r2, r3 are resistors R1 respectively. , R2, R3 resistance values).

The output voltage at the terminal c of the transistor Q1 is divided by the resistors R1 and R2, the divided voltage value V ₁ is input to the controller 1 together with the reference voltage value V _ref1 , and the difference voltage is the transistor Q1. Output to terminal b of (feedback)
The charging voltage V is controlled to be constant. The voltage value V ₂ of the resistor R3 through which the charging current i flows is input to the controller 2 together with the reference voltage value V _ref2 , and the difference voltage is output to the terminal b of the transistor Q1 to control the charging current i constant. Further, the voltage value V ₂ of the resistor R3 is input to the comparator 3 together with the reference voltage value V _ref3 , and when the voltage value V ₂ becomes lower than the voltage value set by the reference voltage value V _ref3 , the comparator 3 _turns on the switch SW1. Turn off and stop charging.

FIG. 4 is a diagram showing charging characteristics of a conventional charging device. While the voltage v of the secondary battery B at the initial stage of charging is lower than the constant voltage value V _B , the controller 2 operates, and the controller 2 controls the charging current i to a constant current value I ₁ so as not to become an overcurrent. . This period (0 to H ₁ ) is called a constant current region. When charging progresses and the voltage v of the secondary battery B reaches a constant voltage V _B , the controller 1 operates. The controller 1 replaces the controller 2 and controls the voltage v of the secondary battery B to a constant voltage value V _B so as not to become an overvoltage. This period (H _{1 to} H ₂ ) is called a constant voltage region. Further, when the charging progresses and the charging current i becomes lower than the constant current value I ₂ , the comparator 3 operates and the switch SW1
Is turned off and charging is completed.

[0006]

However, in the conventional charging device, the time in the constant voltage region (H _{1 to} H ₂ ) is long, and moreover, the amount of accumulated charging energy is small. For example, the charging energy storage amount is only about 20 to 30% in the constant voltage region, while it is about 70 to 80% in the constant current region. Moreover,
It takes (H ₂ −H ₁ ) / H ₁ ≈1.5 times. Further, the total charging time is about twice as long as the charging time of the Ni-Cd (nickel-cadmium) battery, and the conventional constant voltage type charging device has a problem that the charging time is very long.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and eliminates the above-mentioned problems and provides a charging device that shortens the charging time by performing rapid charging by using a pulse voltage in a constant voltage region during charging. The purpose is to provide.

[0008]

In order to solve the above-mentioned problems, the present invention charges the charging voltage v after charging the secondary battery B after the terminal voltage v of the secondary battery B reaches a predetermined voltage value V _B. In a charging device for charging with a constant voltage value V _B , a comparator 4, which detects that the secondary battery B has reached a predetermined voltage value V _B , and a pulse voltage are generated, as shown in FIG. A pulse voltage generator 5 is provided, and when it is detected that the secondary battery B of the comparator 4 has reached a predetermined voltage value V _B , the output voltage of the pulse voltage generator 5 is superimposed on the voltage value V _B for charging. Or the charging voltage V is switched to the output voltage of the pulse voltage generator 5 to perform charging, thereby shortening the charging time.

[0009]

According to the present invention, when an overvoltage charging voltage is applied to a secondary battery B such as a lithium-ion battery or a lead battery for a long time, the battery is damaged and the life is shortened. -It is an application of not giving the error. As described in the means for solving the above problems, the pulse voltage generator 5 is provided to generate a pulse voltage having a width that does not give damage to the secondary battery B, and is superimposed on the charging voltage V in the constant voltage region. Charging or switching to the output voltage of the pulse voltage generator 5 and increasing the charging voltage V to increase the charging current i can increase the charging energy per unit time and shorten the charging time. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram showing a configuration example of a charging device of the present invention. As shown in the figure, the charging device of the present invention constitutes a conventional charging device: controller 1, controller 2, comparator 3, transistor Q1, switch SW1, resistors R1, R2, R.
3, a charging device having input terminals T1 and T2, output terminals T3 and T4, and a comparator 4 for detecting a constant voltage region, a pulse voltage generator 5, and a switch SW2.

The DC power source is input from the input terminal T1 to the terminal e (emitter) of the transistor Q1, and the transistor Q1
The charging current i is supplied from the terminal c (collector) of No. 1 to the output terminal T3 through the switch SW1 and is supplied to the secondary battery B connected to the outside. The resistance value r3 of the resistor R3 is a low resistor for detecting the charging current i, and is connected in series with the secondary battery B through the output terminal T4 (r3 << r1, r
2, where r1, r2 and r3 are resistors R1 and R, respectively
2, the resistance value of R3).

The output voltage at the terminal c of the transistor Q1 is divided by the resistors R1 and R2, and the divided voltage value V ₁ is input to the controller 1 together with the reference voltage value V _ref1 , and the difference voltage is the transistor Q1. It is output to the terminal b of and the charging voltage V is controlled to be constant. The voltage value V2 of the resistor R3 through which the charging current i flows is input to the controller 2 together with the reference voltage value _Vref2 , and the difference voltage is output to the terminal b of the transistor Q1 to control the charging current i constant. The above is the same as the conventional charging device.

In the charging device of the present invention, the pulse voltage generator 5 is connected from the input terminal T1 through the switch SW2, and the output signal thereof is superimposed on the output of the conventional transistor Q1 and output as the charging voltage. The diodes D1 and D2 of the output circuit are for preventing the reverse flow of current. Both the voltage value V ₁ and the reference voltage value V _ref4 are input to the comparator 4, and the comparator 4 detects the time when the charging state enters the constant voltage region, turns on the switch SW2, and activates the pulse voltage generator 5,
The pulse output voltage is superimposed on the output of the transistor Q1.

FIG. 2 is a diagram showing the charging characteristics of the charging device of the present invention. As shown in the figure, the pulse voltage generator 5 which operates by entering the constant voltage region intermittently generates a pulse voltage, and the pulse voltage is superposed on the voltage value V _B of the conventional constant voltage to recharge the secondary battery B.
Applied to. Pulse voltage value and pulse voltage generation time t ₁
And the rest time t ₂ are set by the pulse voltage generator 5. Therefore, as shown in FIG. 2, the charging current i is the same as that in the conventional case during the pulse voltage pause time t ₂ , but is larger than the conventional time during the pulse voltage generation time t ₁ . Therefore, charging can be completed in a shorter time H ₃ than the conventional charging time H ₂ (FIG. 4).

Further, the voltage value V ₂ is input to the comparator 3 together with the reference voltage value V _ref3 , and when the charging current i at t ₂ becomes lower than the value set by the voltage reference voltage value V _ref3 during the pulse voltage rest time, it is switched. SW1 is turned off to stop charging.

Further, in the above description, the pulse voltage is applied by superimposing it on the constant voltage value V _B of the prior art, but the voltage value V _B is switched to the pulse voltage of a higher voltage value and applied to change the charging current i. It is also possible to shorten the charging time by increasing and charging.

It is needless to say that the pulse width of the pulse voltage is set so as not to give damage to the secondary battery B.

[0018]

As described in detail above, according to the present invention, the following excellent effects are expected. A pulse voltage generator is provided to generate a pulse voltage with a width that does not give damage to the secondary battery, and in the constant voltage region, charging is performed by superimposing it on the charging voltage or the output voltage of the pulse voltage generator. By switching, raising the charging voltage and increasing the charging current, the charging energy per unit time can be increased and the charging time can be shortened.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a charging device of the present invention.

FIG. 2 is a diagram showing charging characteristics by the charging device of the present invention.

FIG. 3 is a diagram showing a configuration example of a conventional constant voltage charging type charging device.

FIG. 4 is a diagram showing a charging characteristic of a conventional constant voltage charging type charging device.

[Explanation of symbols]

 1 controller 2 controller 3 comparator 4 comparator 5 pulse voltage generator Q1 transistor D1 diode D2 diode R1 resistor R2 resistor R3 resistor SW1 switch SW2 switch B secondary battery T1 input terminal T2 input terminal T3 output terminal T4 output terminal

Claims (1)

[Claims] 1. A charging device for charging a rechargeable battery, wherein the rechargeable battery is charged at a constant voltage after the rechargeable battery voltage reaches a predetermined voltage, wherein the rechargeable battery has a predetermined voltage. When the voltage detection means detects that the voltage of the secondary voltage has reached a predetermined voltage, the pulse voltage generation means for detecting the arrival of the pulse voltage and the pulse voltage generation means for generating the pulse voltage are provided. A control means for superimposing the pulse output voltage of the means on the charging voltage for charging, or for switching the charging voltage to the pulse output voltage of the pulse voltage generating means for charging with the pulse output voltage. Charging device to do.