JPH0618469B2 - Sealed lead acid battery charger - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed lead acid battery charger.

2. Description of the Related Art Conventionally, batteries that have been left after being over-discharged (hereinafter referred to as "over-discharged batteries") have been a problem with sealed lead-acid battery chargers.
There is rechargeability for. This is because the charging current is difficult to flow because the internal resistance of the over-discharged battery is high. In particular, in the case of a so-called cathode absorption type sealed lead-acid battery, in which oxygen generated at the anode is consumed by the cathode active material during charging, charging with a minute current (hereinafter referred to as "trickle charging") is detected after the end-of-charge voltage is detected. Is often used.

When an over-discharged battery is charged by this type of charger, the internal resistance of the over-discharged battery is high, so that the charging voltage rises immediately after the start of charging and trickle charging occurs, resulting in almost no charging. As one of the methods for solving this drawback, as described in the specification of Japanese Patent Application No. 61-16196, which was previously filed, after applying a current in the reverse direction to the normal state to an over-discharged battery ( There is a method to return to normal charging (hereinafter referred to as "reverse charging").

Problems to be Solved by the Invention When the above charging method is applied to an actual charger, there is a problem in that it may not be recovered depending on the conditions for ending reverse charging.

As a condition for ending the reverse charge, the simplest method is to make the reverse charge time constant. But with this method,
Overcharged batteries with extremely high internal resistance have poor recoverability, and when the internal resistance is relatively low, reverse charging more than necessary increases the charging time, heat generation during charging, and life characteristics after recovery. There are adverse effects such as deterioration. An example of this is shown below.

The battery used is a sealed lead acid battery of 4V and 4Ah.
The charging characteristics when the reverse charging time is 60 minutes are shown in FIGS. 4 and 5. Figure 4 shows the charging characteristics of an over-discharged battery with an internal resistance of approximately 300Ω, and Figure 5 shows the charging characteristics when the internal resistance is approximately 1600Ω.

When the internal resistance was about 300 Ω, normal charging was started after reverse charging, but when the internal resistance was high at about 1600 Ω, normal charging was resumed, then trickle charging was started early, and charging was not performed. Table 1 shows an overdischarged battery with an internal resistance of about 300Ω. The maximum battery surface temperature when the reverse charging time is changed is shown. Obviously, the longer the reverse charging time, the more heat is generated. FIG. 6 shows the cycle life characteristics after recovery of the over-discharged battery which was recovered after the reverse charge time was 60 minutes. The internal resistance of an over-discharged battery with an internal resistance of approximately 10Ω is approximately 300Ω.
Compared to the case of, the capacity decreases faster, and the life is about 150 cycles.

From the above, when reverse charging is performed to recover, it is considered that a method of performing reverse charging according to the internal resistance of the over-discharged battery is preferable.

Means for Solving the Problems The present invention solves the above-mentioned problems, and only an over-discharged battery having a high internal resistance performs reverse charging according to the internal resistance.
When the AC voltage component included in the charging voltage has a certain value A or more and the DC voltage component has a certain value B or more, reverse charging is performed for a certain time, and the AC voltage component included in the charging voltage has the certain value A or more and When the DC voltage component is equal to or less than the constant value B, a current is supplied in the same direction as normal charging, and a means for performing normal charging only when the AC voltage component included in the charging voltage is equal to or less than the constant value A is provided. It is a feature.

Action The present invention has the above-mentioned characteristics, so that it is possible to perform reverse charging according to the internal resistance only when the internal resistance of the over-discharged battery is high, and to recover by normal charging when the internal resistance is not high. Become. This is the same as when the internal resistance of the over-discharged battery is high, the DC component contained in the charging voltage increases, and when the internal resistance is not high, the AC voltage component contained in the charging voltage decreases until it becomes the same as usual. This is because it is possible to recover by normal charging by passing a current in the direction.

Therefore, according to the present invention, when an over-discharged battery having a high internal resistance is charged, it can be recovered by repeating reverse charging for a certain time until the DC component included in the charging voltage becomes a certain value or less. Further, in the case of an over-discharged battery whose internal resistance is not high, it is possible to recover by applying a current in the same direction as normal charging until the AC voltage component contained in the charging voltage becomes a certain value or less.

Embodiment An embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a circuit diagram of a charger using the present invention. During normal charging, trickle charging is started after the end-of-charge voltage is detected. When the first end voltage detection unit 5 detects the end-of-charge voltage, the control unit 4 operates and controls the current control unit 3 to control the resistance 2. The trickle charging is started.

During charging of the over-discharged battery, the AC voltage component generated in the sealed lead storage battery 15 is applied to the resistor 12 through the capacitor 11. This AC voltage is input to the AC voltage detection unit 10 whose detection voltage is A. The second voltage detection unit 9 whose detection voltage is B detects the DC voltage component included in the charging voltage, and the outputs of the voltage detection unit 9 and the current / voltage detection unit 10 are the same as the input of the reverse charging control unit 8. Become. The output of the reverse charge control unit 8 is
The timer 6 and the control unit 4 are controlled. The reverse charge control unit 8
When the AC voltage detection unit 10 and the second voltage detection unit 9 operate, the timer 6 is controlled, the timer 6 causes a current to flow through the coil 7 of the relay, switches the contact 13 of the relay, and controls the control unit 4 to perform reverse charging. A current is passed to perform reverse charging for a fixed time. or,
When only the AC voltage detecting unit 10 operates, the reverse charging control unit 8 controls the control unit 4 to supply the charging current. By such an operation, it is possible to perform reverse charging only for an over-discharged battery having a high internal resistance, and to recover a battery having a low internal resistance without performing reverse charging. In FIG. 1, reference numeral 1 is a transformer rectifier, and 14 is a diode.

Charging characteristics when using a sealed lead acid battery of 4V and 4Ah are shown in FIG. 2 and FIG. The end-of-charge detection voltage is 4.9
V, the set voltage of the timer is 15 (min), the AC component detection voltage A is 0.5V ^PP , and the DC component detection voltage B is 5.6V.

Fig. 2 shows the charging characteristics when the internal resistance is about 1600Ω. After repeating reverse charging 6 times, normal charging is started. Fig. 3 shows the charging characteristics when the internal resistance is about 50Ω. Normal charging starts about 30 minutes after the start of charging without reverse charging.

Effects of the Invention As described above, the present invention focuses on the fact that an AC voltage component and a DC voltage component contained in the charging voltage and an over-discharged battery having a high internal resistance can be recovered without performing reverse charging,
When the internal resistance is high, it is possible to repeat the reverse charging depending on the internal resistance, and when the internal resistance is low, it is possible to recover without performing the reverse charging. Therefore, it is possible to minimize the reverse charge, and the industrial value is extremely great.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIGS. 2 and 3 are charging characteristic curve diagrams when the charger according to the present invention is used, and FIGS. 4 and 5 show reverse charging time. FIG. 6 is a characteristic curve diagram showing the charging characteristic when it is constant, and FIG. 6 is a characteristic curve diagram showing the cycle life characteristic after the reverse charge recovery. 3 is a current control unit, 4 is a control unit, 5 is a first voltage detection unit, 6
Is a timer, 8 is a reverse charge control unit, 9 is a second voltage detection unit, 10
Is an AC voltage detector, 15 is a sealed lead-acid battery

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akio Komaki 2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo Shin-Kindo Electric Co., Ltd. Examiner Akira Suzuki

Claims (1)

[Claims] 1. When the AC voltage component included in the charging voltage has a certain value A or more and the DC voltage component has a certain value B or more, a current in a direction opposite to normal charging is supplied for a certain period of time and included in the charging voltage. When the AC voltage component to be generated is equal to or higher than the constant value A and the DC voltage component is equal to or lower than the constant value B, a current in the same direction as normal charging is applied, and when the AC component included in the charging voltage is equal to or lower than the constant value A. A sealed lead-acid battery charger characterized in that it is provided with means for performing normal charging only.