JPS62103986A - Hermetically sealed lead storage battery - Google Patents

Abstract

PURPOSE:To enhance the volumetric energy density of a battery employing a battery jar of no moisture permeation, by setting the specific gravity of an electrolytic solution at 1.34-1.36 at a temperature of 20 deg.C. CONSTITUTION:An electrolytic solution of 1.35 in specific gravity at a temperature of 20 deg.C is used to assemble a hermetically sealed lead storage battery of 12V and 0.8Ah. An aluminum film layer is provided at a thickness of 50mu on the surface of a battery air to prevent the permeation of moisture. At the final stage of discharge, the specific gravity of the electrolytic solution approaches 1 so that the recovering property of the battery deteriorates. For that reason, 4,000-8,000ppm of Na ions are added to the electrolytic solution. The volume of the battery is thus made smaller than a conventional battery with an electrolytic solution of 1.30 in specific gravity, to enhance the volumetric energy density of the former battery.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a sealed lead acid battery.

BACKGROUND OF THE INVENTION Generally, sealed lead-acid batteries have very limited capacity because the electrolyte is non-fluidized. However, while the battery is in use, water vapor permeates through the battery case, reducing the amount of electrolyte in the battery case, leading to a decrease in discharge capacity. In order to ensure the maximum amount of electrolyte in advance so that the discharge capacity does not deteriorate even if such a phenomenon occurs, a fine glass fiber non-woven fabric with a high liquid retention capacity is used.

The electrolyte, sulfuric acid, is held in a lead-acid battery. Normally, the specific gravity of automobile batteries is 126 to 1.28 (a
Since the liquid volume is limited in sealed lead-acid batteries, the concentration is slightly high, 1.28 to 1.30.
The electrolyte with a specific gravity of (a t 20°C) has been used up.

Problems to be Solved by the Invention By the way, new battery cases are being used for the purpose of further extending the life of sealed lead-acid batteries. The battery case has a layer of polyvinylidene chloride or metal film on its surface, which has almost no moisture permeability. For this reason, it was necessary to ensure that the amount of liquid was kept at the minimum necessary level (although it was necessary to review the optimal specific gravity of the electrolyte in consideration of improving energy density).

Means for solving the problem Consisting of a minimum amount of sulfuric acid to ensure battery capacity 1.20
The volumetric energy density was measured by combining a sulfuric acid solution with a specific gravity of ~1.40 (a t 20''C), an electrode plate holding it, and a glass fine fiber nonwoven fabric. The results are shown in the drawings.

From the figure, it was found that the electrolytic solution with a specific gravity of 1.34 to 1.36 (at 20°C) had a large value.

Effects The present invention is capable of improving the volumetric energy density of a battery using a battery case without moisture permeability.

Example An embodiment of the present invention will be described.

12vO using electrolyte specific gravity 1.35 (at 20℃)
A 68Ah sealed lead acid battery was assembled.

In addition, in order to prevent moisture permeation, an oxide film layer (thickness: 50 μm) was provided on the surface of the film. Further, at the end of discharge, the specific gravity of the electrolyte approaches 1, resulting in poor recovery performance, so 4000 to 8000 ppmffi of Na ions were added to the electrolyte.

The volume was reduced by about 6 points compared to the case where a conventional specific gravity of 1.30 was used, and the volumetric energy density was increased by 5 points as shown in the drawing. In addition, the volumetric energy density ratio (
Excellent) is the one in which the volumetric energy density at the electrolyte ratio i1.3 (at 20° C.) is 100.

Effects of the Invention As described above, the present invention makes it possible to increase the volumetric energy density of a sealed lead-acid battery.

[Brief explanation of drawings]

The drawing is a characteristic curve diagram showing the relationship between electrolyte specific gravity and volumetric energy density ratio.

Claims (1)

[Claims] The electrode plate group consists of an anode plate with lead dioxide as a reactant, a cathode plate with lead as a reactant, and a nonwoven fabric made of fine glass fibers that can hold the electrolyte interposed between the anode and cathode plates to suppress the permeation of water vapor. A sealed lead acid battery housed in a battery case, wherein the electrolyte has a specific gravity of 1.34 to 1.36 (at 20°C).