JPS601755A - Method of stirring electrolyte of lead storage battery - Google Patents

Abstract

PURPOSE:To prevent any decrease in the discharge capacity of a lead storage battery as well as any deterioration of the lower portions of plates which might be caused under an atmosphere of high specific gravity by detecting terminal voltage or increase in the terminal voltage during charging and applying pressure fluctuation to intracellular spaces according to the result of the detection. CONSTITUTION:A monoblock lead storage battery 1 is constituted, for example, by unifying six cells. It has an internal space extending over the cells. A connection conduit 2 for connecting the cell spaces of adjacent storage batteries 1 is led to an adjacent storage battery or apparatus. The exhaust part 5 of a storage battery group has a valve function opening only into the outside. A charging apparatus 6 and a decompression pump 7 work according to necessity by detecting the terminal voltage of the storage battery 1 by means of the charging apparatus 6. For instance, by driving the decompression pump 7 when the terminal voltage reaches 2.4V/cell, gas contained in the plate group and a small amount of gas produced by charging expand before rising through electrolyte and being discharged thereby stirring the electrolyte.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for stirring an electrolyte solution for a lead-acid battery for cycle service.

Overcharging accelerates the deterioration of the positive electrode plate of lead-acid batteries, so recently there are current-regulated constant-voltage charging or quasi-constant-voltage charging that detects the terminal voltage and uses a timer to terminate charging to reduce overcharging. It is widespread. However, a new problem has arisen with this type of charging with little overcharging. To explain this, an automotive lead-acid battery is 20 amperes (
Constant current discharge of A>, maximum current 20A1 set voltage 2.4
FIG. 1 shows the results of changes in terminal voltage and changes in electrolyte specific gravity when constant current/constant voltage charging of the V/cell was performed. The specific gravity of the electrolyte was measured at two locations, one slightly above the upper end of the electrode plate, and the other at the upper end.The specific gravity of the upper part significantly decreased due to discharge, and did not recover much during charging. On the other hand, in the lower part, the specific gravity decreases little during discharge, but increases significantly during charging. Therefore, there is a considerable difference in the specific gravity of the electrolyte between the upper and lower parts. Such stratification of the electrolytic solution is undesirable because it causes a decrease in discharge capacity and deterioration of the lower part of the electrode plate in a high specific gravity atmosphere.

The present invention provides an electrolyte stirring method that can eliminate the above-mentioned drawbacks of lead-acid batteries with a small amount of overcharge. It consists in applying fluctuations.

The present invention will be explained below using FIG. 2.

In FIG. 2, reference numeral 1 denotes a monoblock type lead-acid FF battery, which is made up of, for example, six cells, and the space above each cell is continuous inside. Reference numeral 2 denotes a connecting conduit that connects each cell space, etc. of adjacent storage batteries 1, and extends to adjacent storage batteries or equipment. 3 is a terminal of the storage battery 1, 4.4' is a conductor, and 5 is an exhaust part of the storage battery group, which has a valve function that opens only to the outside. 6 is the charger, 7 is the vacuum pump, ? 5. Terminal voltage of battery 1 is detected by charger 6 and activated as required. Note that the connecting conduit 2 can also be used when replenishing the storage battery group with water.

Next, the present invention will be explained in detail. Discharge and charge under the same conditions as shown in Figure 1, and the terminal voltage was 2.4V /
When the cell is reached, the vacuum pump 7 is operated for only 5 minutes. When the inside of the storage battery 1 is in a reduced pressure state, the gas contained in the electrode plate group and a small amount of gas generated by charging expand in volume compared to the case under normal pressure, rise in the electrolytic solution, and are discharged. This rise in gas stirs the electrolytic solution and eliminates stratification. This situation is shown in FIG. 1 by dotted lines.

When charging a lead-acid battery, there is a period when the terminal voltage changes significantly when charging is almost completed. Therefore, the decompression pump 7 may be operated by detecting the rate of rise in the terminal voltage. Further, for the same reason, the increase value of the terminal voltage may be detected.

Furthermore, by detecting the terminal voltage or its increased value during charging of the lead-acid battery and operating the decompression pump 7, the electrolyte can be stirred when the charging of the lead-acid battery is almost completed. , it can efficiently (reliably eliminate) the stratification of the electrolyte.Also, if the battery is over-discharged and the specific gravity of the electrolyte is extremely reduced, a high normal voltage may be shown at the beginning of charging. When the battery is depressurized and the electrolyte is stirred, not only the concentration becomes uniform, but also the electrolyte penetrates into the inside of the electrode plate, making it easier to charge.

Furthermore, since the gas accumulated in the battery can be easily handled even if it is pressurized and then returned to normal pressure, a similar effect can be obtained by pressurizing it with a compressor instead of the decompression pump 7. That is, pressure fluctuations may be applied to the storage battery.

As described above, according to the present invention, the stratification phenomenon of the electrolyte in a lead-acid battery for cycle service with a small amount of overcharge can be efficiently and reliably eliminated by simple means, leading to a decrease in discharge capacity and deterioration of the lower part of the electrode plate. can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram showing changes in terminal voltage and electrolyte specific gravity during discharging and charging of a lead-acid battery, and FIG. 2 is a system diagram for explaining the electrolyte stirring method for a lead-acid battery according to the present invention.

Claims (1)

[Claims] A method for stirring an electrolyte solution for a lead-acid battery, characterized by detecting the terminal voltage or its rising value during charging and applying pressure fluctuations to the internal space of the cell.