JPS6323623B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for restoring the capacity of a lead-acid battery that has become unchargeable due to overdischarge.

The only conventional method for restoring a storage battery that has become unchargeable due to overdischarge is to apply a high voltage to the battery and charge it with a minute current. The problem with this method is that it requires a special charger and takes a long time to complete recovery, making it impractical. When charging is performed with a large current to shorten this recovery charging time, the battery generates heat, which may impair the performance and life of the battery.

In a storage battery that has become unchargeable due to overdischarge, coarse particles of lead sulfate formed at the interface between the positive electrode lattice surface and the active material exhibit a semiconductor-like rectifying effect, and when current flows in the normal charging direction. By applying an AC voltage to a storage battery in this state, the battery initially has a high internal resistance in the charging direction, but it has a relatively low internal resistance in the discharging direction. Although the amount of electricity flowing in the discharge direction is large, the amount of electricity gradually becomes equal or close to it in both directions. After this initial discharge, regular charging is possible using a normal charging method.

Embodiments of the present invention will be described below with reference to the drawings. In Figure 1, when all the switches SW of the charger are connected to the a side, the constant voltage circuit C operates and a regular constant voltage charging circuit is configured, and when all the switches SW of the charger are connected to the b side, the battery 1
A circuit is configured to which AC voltage 2 is applied to. Note that T is a step-down transformer and R is a full-wave rectifier.
Now, turn the switch SW to the side a to connect the over-discharged battery 1 that could not be charged to the charging terminal, turn the switch SW to the b position to connect it, apply AC voltage to the battery 1, and connect the battery 1 to the light emitting diode L. When it lights up, turn the switch SW to side a again to perform normal charging.

The battery whose capacity was restored by such charging had the following state compared to its initial capacity before overdischarge.

Initial capacity 3.2Ah Capacity after recovery charge 3.1Ah Capacity recovery rate 96.9% Based on the same principle, in the charge recovery circuit without transformer T shown in Figure 2, after applying high voltage alternating current to battery 1 in an overdischarged state, The recovery situation when connected to a voltage charger and subjected to regular recovery charging was also exactly the same as the above results.

Based on the characteristics of over-discharged batteries as mentioned above, use the charging circuit shown in Figure 3, and for batteries where no current flows even if the interlocking switch SW is turned to side a and normal charging is performed, turn the switch SW to side b. to reverse charge by passing current in the discharging direction, and then turn the switch SW to a.
Even if you charge it by laying it on its side, you can get almost the same recovery rate as above.

According to the capacity recovery method of the present invention, even if a storage battery is over-discharged and cannot be recharged using the normal charging/discharging method, by applying an AC voltage or performing reverse charging, the surface of the positive electrode grid can be restored. By destroying a semiconducting substance that exhibits a rectifying effect generated at the interface with the active material and making it possible to conduct electricity through this substance, a state in which charging can be recovered in a short period of time can be achieved, which is a major practical advantage. worth it.

Furthermore, the present invention has the advantage of being of high economic value because the capacity of the battery can be restored by adding an inexpensive circuit to a normal charging circuit or by preparing a separate circuit.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a charging circuit used for capacity recovery in an embodiment of the present invention, and FIGS. 2 and 3 are circuit diagrams in other embodiments. 1... Over-discharged battery, 2... AC power supply, T...
...transformer, R...full wave rectifier, C...constant voltage circuit, SW...switch.

Claims (1)

[Claims] 1. A lead-acid battery that has become unchargeable due to over-discharge,
A method for restoring the capacity of a lead-acid battery, characterized by applying an alternating voltage or reverse charging to destroy a semiconducting material formed at the interface between a positive electrode lattice surface and an active material, and then performing regular charging.