JPH10214635A - Lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress reduction of a quantiy of electrolyte under a high temperature in particular and water evaporation caused by steam evaporation of the electrolyte, by floating a synthetic resin foam, a hollow synthetic resin plate or a synthetic resin balloon on electrolyte surface. SOLUTION: In a lead-acid battery for a vehicle, a synthetic resin foam plate 9 is put in a cell in advance before welding a lid 3, and is arranged so that it is floated on electrolyte surface. The synthetic resin foam plate 9 is made so that its position descends along with descent of the electrolyte surface If the electrolyte 10 is reduced. A shape of the synthetic resin foam plate is made smaller than an inner dimension of a battery container so that it can move around easily by fluctuation of electrolyte surface. For instance, the rate for the synthetic resin foam plate to cover the electrolyte surface is set for 95%, and in another battery, it is left as in the past. When comparing both batteries, although life performance of a battery reduces as a test temperature increases, the battery with the synthetic resin floated shows a performance increase of more than 40%, especially in a high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a liquid lead storage battery.

[0002]

2. Description of the Related Art Liquid-type (open type) lead-acid batteries are used in many applications, such as starting and lighting vehicles, electric vehicles such as battery forklifts, and stationary devices. In recent years, various improvements have been made to lead-acid batteries in order to suppress self-discharge during standing and to reduce water replenishment due to decomposition of electrolyte (dilute sulfuric acid) during use. Typical examples thereof include a reduction in the amount of antimony added to the positive electrode lattice alloy or the use of a positive electrode lattice made of a lead alloy (lead-calcium-tin-based alloy) containing no antimony.

[0003]

In the case of a lead-acid battery for automobiles, the temperature in the engine room where the lead-acid battery is installed can be as high as 70 ° C. or more in summer. At such a high temperature, not only the liquid reduction due to the decomposition of the electrolytic solution (water decomposition) during the overcharging of the storage battery, but also the evaporation of water due to the increase in the vapor pressure of the electrolytic solution becomes a serious problem. Therefore, simply promoting the reduction of antimony or antimony free as described above was not sufficient to suppress a decrease in the amount of electrolyte particularly at high temperatures.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a problem that a synthetic resin foam, a hollow synthetic resin plate or a synthetic resin balloon is floated on the electrolyte surface of a liquid lead storage battery. It is characterized by.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In a lead-acid battery according to the present invention, a synthetic resin foam, a hollow synthetic resin plate or a synthetic resin balloon is floated on an electrolyte surface. By doing so, the evaporation of water from the electrolyte surface can be prevented, and the liquid reduction characteristics can be improved.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

[0007] An ordinary lead-acid battery for automobiles using a positive electrode grid made of a Pb-Sb-based alloy (1.7% by weight Sb) and a negative electrode grid made of a Pb-Ca-Sn-based alloy was prepared and the following test was conducted. Was done. In one storage battery, as shown in FIG. 1, a synthetic resin foam plate 9 was previously placed in the cell before the lid 3 was welded, and was arranged so as to float on the electrolyte surface. When the electrolytic solution 10 decreases, the position of the synthetic resin foam plate 9 decreases in accordance with the decrease in the liquid level. The shape of the synthetic resin foam plate 9 was made slightly smaller than the inner size of the battery case 2 so as to easily move due to the fluctuation of the electrolyte surface. Here, the ratio of covering the electrolyte surface of the synthetic resin foam plate was 95%. The other battery was used as a conventional product for comparison. In FIG. 1, 1
Denotes an electrode plate group, 4 denotes a terminal, 5 denotes an electrode pole, 6 denotes a liquid inlet, 7 denotes a partition wall penetrating connection portion, and 8 denotes a strap.

[0008] The test battery is a 55D23 lead-acid battery for automobiles having a nominal capacity of 48 Ah (5 hour rate) and a nominal voltage of 12 V described in JIS D 5301. These test batteries were subjected to a light load life test. The test was performed in accordance with JIS D 5301, but here, the environmental temperature was changed to four types of 40, 60, 75, and 90 ° C. Also, the weight of the battery was measured during the light load life test,
The amount of liquid reduction during the cycle was investigated.

FIG. 2 shows the relationship between the life performance of these batteries and the test temperature, and FIG. 3 shows the relationship between the amount of liquid reduction during the life test (average amount of liquid reduction per charge / discharge cycle) and the test temperature. .

As shown in FIG. 2, although the life performance of these batteries decreased as the test temperature was increased, the batteries in which the synthetic resin foam plate was floated on the electrolytic solution surface according to the present invention, especially at high temperatures, were not used. It showed excellent life performance. The reason why the battery according to the present invention has an excellent life performance is that, as shown in FIG. 3, the amount of liquid reduction during the life test of the product of the present invention is smaller than that of the conventional product, and therefore, the increase in the specific gravity of the electrolyte can be suppressed. it is conceivable that. The reason why the synthetic resin foam plate was floated on the electrolyte surface to improve the liquid-reducing property is considered to be that the evaporation of the water from the electrolyte became less likely to occur by covering the electrolyte surface with this.

The synthetic resin foam plate used here has a thickness of 1
mm polystyrene foam. If it is a floating body that covers the electrolyte surface, it is not limited to this, and a small piece of synthetic resin foam,
A hollow synthetic resin plate, a synthetic resin balloon or the like can be used. In addition, when a synthetic resin plate is used, if it is colored in an easy-to-see color, the liquid surface is easy to see when rehydrating, and it is convenient.

[0012]

As described above, according to the present invention, a lead-acid battery in which a synthetic resin foam, a hollow synthetic resin plate or a synthetic resin balloon is floated on the surface of an electrolyte according to the present invention has a reduced liquid content during use at high temperatures. Its industrial value is great, as it hardly occurs and stable battery performance can be maintained for a long period of time.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of the lead storage battery of the present invention.

FIG. 2 is a diagram comparing the light load life performance of lead storage batteries.

FIG. 3 is a diagram showing a liquid reduction characteristic during a light load life test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode group 2 Battery case 3 Lid 4 Terminal 5 Electrode 6 Injection port 7 Partition penetration connection part 8 Strap 9 Synthetic resin foam board 10 Electrolyte

Claims (1)

[Claims] 1. A lead-acid battery in which a synthetic resin foam, a hollow synthetic resin plate or a synthetic resin balloon is floated on an electrolyte surface.