JPH0693366B2 - Sealed lead acid battery - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of a sealed lead-acid battery.

Conventional technology and its problems There are two types of sealed lead-acid batteries, the retainer type and the gel type, in which the negative electrode absorbs oxygen gas generated during charging of the battery. The retainer type inserts a mat-shaped separator (glass separator) made of fine glass fibers between the positive electrode plate and the negative electrode plate, thereby holding the sulfuric acid electrolyte necessary for discharge and separating the two electrodes. In recent years, it has been widely used as a backup power source for portable devices and computers. However, the retainer type has a drawback that the discharge capacity is limited by the amount of electrolytic solution at low rate discharge because it cannot hold a sufficient amount of electrolytic solution, which is an obstacle to the widespread use of this type of sealed battery.

On the other hand, the gel type has a drawback that the battery performance is inferior to that of the retainer type.

Means for Solving the Problems The present invention eliminates the above-mentioned drawbacks of conventional sealed lead-acid batteries, and provides a sealed lead-acid battery having excellent discharge performance, the main point of which is to charge and discharge the battery. The necessary and sufficient amount of sulfuric acid electrolyte is filled and arranged around the separator and the electrode plate group, and the fine silica powder is granulated using a binder to impregnate and hold the powder. . The present invention will be described below based on examples.

Example A positive and negative electrode grid made of Pb-Ca-Sn alloy was filled with ordinary positive electrode and negative electrode pastes and aged to prepare an unformed electrode plate. Then, an electrode plate group was prepared using these positive electrode and negative electrode non-formed electrode plates and a papermaking separator made of fine glass fibers (fiber diameter 0.5 to 1 micron) having sufficiently high porosity and surface area, and inserted into a battery case. . So the particle size is
Fine silica powder of 10 to 40 millimicrons is kneaded with water containing 15% of methyl methacrylate as a binder, granulated to a particle size of 100 to 200 microns, and dried, and then the battery wall and electrode plate They were closely packed while applying vibration to and from the group. The granules filled here are 100% of fine primary silica particles that are condensed.
The secondary particles were ~ 200 microns, and the granulated particles had a porosity of 90% or more, and a porosity of about 85% when filled in the gaps.

After filling the granulated material in this way, the lid was adhered, an exhaust valve was attached, and a sealed lead-acid battery having a nominal capacity of 4.5 Ah was produced and subjected to a capacity test. For comparison, conventional retainer type batteries and gel type batteries using the same lot of electrode plates were prepared and their performances were compared with the products of the present invention. Table 1 shows the test results.

From this test result, when comparing the retainer type and the gel type, the retainer type was superior in high rate discharge performance to the gel type because the electrolytic solution specific gravity was slightly high. On the other hand, the product of the present invention has improved performance by 10 to 20% in both low rate discharge and high rate discharge as compared with these conventional sealed lead acid batteries. This is because by packing silica granules around the electrode plate group, it was possible to retain a larger amount of electrolytic solution than that of the retainer type, and to make the electrolytic solution specific gravity higher than that of the gel type. If the specific gravity of the electrolyte is increased by the gel method, the performance of the gel changes and the battery performance rather deteriorates.

EFFECTS OF THE INVENTION As is apparent from the above-described examples, the sealed lead-acid battery according to the present invention is obtained by impregnating and holding the electrolytic solution in the granules of the silica fine powder arranged around the fine glass paper separator and the electrode plate group. The performance of the conventional sealed lead-acid battery can be greatly improved, and its industrial value is great.

Claims (1)

[Claims] 1. In a sealed lead-acid battery in which oxygen gas generated during charging of the battery is absorbed by a negative electrode, an electrode plate group consisting of a positive electrode plate, a negative electrode plate, and a papermaking separator made of fine glass fibers is pressed to put it in a battery case. In addition to storing the electrode in the electrode plate group, a porous powder obtained by granulating 10-40 mm micron silica fine powder with a binder is placed around the electrode plate and placed to provide the electrolyte necessary for battery charging and discharging. A sealed lead-acid battery in which the above-mentioned papermaking separator and the above-mentioned granulated powder arranged around the electrode plate group are impregnated and held.