JP2000082489A - Lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve service life of a lead-acid battery. SOLUTION: In an electrode group, for which a positive electrode plate with active material filled in a plane lattice has framed skeletons 1, inner skeletons 2 and a lug portion 3 and a negative electrode plate are combined via a separator, a portion facing opposite the lug portion 3 of the negative electrode plate, of the positive electrode lattice is formed cut off obliquely. The lattice is formed in casting with a lead-calcium based alloy. Lead power mainly containing lead monoxide and lead is compounded with dilute sulfuric acid to prepare a paste active material. The paste active material is applied to the lattice to manufacture a green positive electrode plate following aging and drying processes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to extending the life of a lead storage battery.

[0002]

2. Description of the Related Art Lead-acid batteries are widely in demand for backup power supplies for computer equipment and communication equipment, power sources for electric vehicles, and emergency power supplies for buildings and hospitals. recent years,
There is an extremely strong demand for extending the life of lead-acid batteries used in these devices. As the positive electrode plate and the negative electrode plate of the above-mentioned lead-acid battery, a paste type electrode plate manufactured by filling a paste-like active material into a grid made of a lead alloy is generally used. As shown in FIG. 4, the conventional lattice body has a substantially rectangular lattice shape, and is constituted by a frame bone 1 on the periphery, an inner bone 2 on the inside, and a current collecting ear 3. . The positive electrode plate 4 and the negative electrode plate 5 are combined via a separator to form an electrode group (FIG. 5). The main factor affecting the life of the battery is a short circuit between the positive electrode plate 4 and the negative electrode plate 5.
That is, it has been clarified that the grid for the positive electrode is corroded by oxidation and is elongated, and the elongated positive electrode plate 4 and the ear portion 3 of the negative electrode plate 5 are short-circuited, and the life is often extended.

[0003] For the reasons described above, development of a positive electrode lattice body which is hardly corroded and hard to expand has been studied. In addition, in order to suppress corrosion of the grid for the positive electrode, means for lowering the specific gravity of sulfuric acid used as the electrolyte, means for lowering the calcium concentration in the lead-calcium alloy which is a raw material of the grid, and Means for thickening the body are being studied. However, the use of a means for reducing the specific gravity of sulfuric acid causes a decrease in the capacity of the battery, a decrease in the calcium concentration in the lead-calcium alloy causes a decrease in the strength of the lattice, which makes handling difficult, and the thickness of the lattice is reduced. When the thickness is large, there is a problem that the battery weight increases and the cost increases.

Further, means for inserting an insulating synthetic resin film or the like between the vicinity of the ear portion 3 of the negative electrode plate 5 and the positive electrode plate 4 is also being studied. However, this method has problems that the workability is inferior and the cost is high.

On the other hand, as reported in Japanese Patent Application Laid-Open No. 8-293307, means for suppressing a curve caused by corrosion of the grid body by providing a cut portion in a part of the frame of the grid for the positive electrode has been studied. ing. However, when this method is used, there is a problem that the physical strength of the positive electrode plate 4 itself is reduced, so that handling becomes difficult.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a long-life lead-acid battery which is easy to handle and suppresses a short circuit between a positive electrode plate 4 and a lug 3 of a negative electrode plate 5 by a low-cost method. To provide.

[0007]

In order to solve the above-mentioned problems, in the first invention, an active material is filled in a flat lattice body having a substantially rectangular frame bone 1, inner bone 2, and ears 3. In a lead-acid battery using an electrode group obtained by combining the positive electrode plate 4 and the negative electrode plate 5 and the positive electrode plate 4 and the negative electrode plate 5 with a separator 6 interposed therebetween, the ears of the negative electrode plate 5 in the electrode group In a second aspect of the present invention, the separator has a rectangular shape and is larger than a reaction area of the negative electrode plate. Characterized in that:

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described below.

Example 1 FIG. 1 is a schematic view of a grid for a positive electrode according to the present invention. That is, a portion of the grid for the positive electrode facing the ear 3 of the negative electrode plate 5 is cut off obliquely. The lattice body used in this example was formed by casting using a lead-calcium alloy. Next, a paste-like active material is prepared by kneading lead monoxide and a lead powder mainly composed of lead with dilute sulfuric acid. This paste-like active material was applied to this lattice body, and an unformed positive electrode plate 4 was produced through the steps of aging and impression. This unformed positive electrode plate 4 was subjected to tank formation in dilute sulfuric acid. Then, the positive electrode plate 4 was combined with the conventionally used negative electrode plate 5 and separator 6 to form an electrode group as shown in FIG. .

An overcharge test was performed on the manufactured sealed lead-acid battery at a constant voltage of 13.65 V in an environment of 45 ° C. The battery under test was discharged every 30 days at a temperature of 25 ° C and a discharge current of 6 ° C.
A, a capacity confirmation test was performed at a final voltage of 10.2V.

(Comparative Example) As a comparative example, a sealed lead-acid battery was prepared by using a grid of a conventional shape as the positive electrode plate 4 as shown in FIG. In addition, the manufacturing conditions and test conditions of the battery are exactly the same as those in (Example 1).

FIG. 6 shows the results of a life test under the above conditions.
Shown in In the product of the present invention, the initial capacity is slightly inferior to the conventional product because the electrode area of the positive electrode plate 4 is reduced. However, the tendency of the capacity to decrease is gradual, and the target 1.5 hours is satisfied even after 500 days. on the other hand,
The capacity of the conventional product rapidly decreases after 300 days of testing, and the life of the product has reached 420 days. When these two types of batteries were disassembled after 420 days had elapsed, the battery using the conventional grid had an upper part of the positive electrode plate 4 and a negative electrode plate 5.
In the battery using the product of the present invention, elongation of the grid for the positive electrode was observed, but no short circuit occurred with the ear 3 of the negative electrode plate 5. Was.

The same effect can be obtained even when the shape of the grid for the positive electrode is as shown in FIGS. 2 and 3, and the life of the sealed lead-acid battery can be extended.

[0014]

As described above, the use of the positive electrode grid of the present invention is advantageous in that the life of a lead-acid battery can be extended.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a grid for a positive electrode of the present invention.

FIG. 2 is a schematic view of a grid for a positive electrode according to the present invention.

FIG. 3 is a schematic view of a grid for a positive electrode of the present invention.

FIG. 4 is a schematic view of a conventional positive electrode lattice body.

FIG. 5 shows a state where a positive electrode plate, a separator and a negative electrode plate are combined.

FIG. 6 shows the results of an overcharge life test of a lead storage battery.

[Explanation of symbols]

1: frame bone, 2: inner bone, 3: ear, 4: positive electrode plate, 5: negative electrode plate, 6: separator

Claims (2)

[Claims] 1. A lead-acid battery produced by combining a positive electrode plate and a negative electrode plate, each of which is filled with an active material, in a flat lattice formed of a substantially rectangular frame bone, an inner bone, and an ear via a separator. 2. The lead-acid battery according to claim 1, wherein a dimension in a height direction of the grid for the positive electrode in a portion of the negative electrode plate facing the ear is short. 2. The separator according to claim 1, wherein the separator has a rectangular shape.
2. The lead-acid battery according to claim 1, wherein the lead-acid battery is larger than a reaction area of the negative electrode plate.