JPH0765822A - Lead acid battery - Google Patents

Abstract

PURPOSE:To extend the life of a battery by using an alloy-expanded grid for a positive electrode. CONSTITUTION:Lead alloy containing 0.05-0.09% calcium, 0.06-1.80% tin and 0.005-0.05% bismuth is cold rolled into a sheet and then expanded to form a grid for at least a positive electrode, so that the life of a lead acid battery is improved. With the addition of bismuth, the oxidation resistance of the grid is improved and the oxidation corrosion of a rolled sheet due to expansion is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a lead-acid battery, and more particularly to a maintenance-free type lead-acid battery using a lead-calcium-tin alloy in an anode grid.

[0002]

2. Description of the Related Art A lead-acid battery using a lead-calcium-tin alloy for positive and negative electrode grids is called a maintenance-free battery because it has features such as low self-discharge and excellent storage characteristics. There is.

In batteries using such an alloy system for a grid, a method of expanding a rolled lead alloy sheet to form a grid body has been widely used instead of the conventional casting method.

However, a lead-acid battery using such a lead-calcium-tin alloy as the anode has a lower adhesion between the lattice and the active material than a battery using the lead-antimony alloy as the anode. It is generally known that performance degradation is likely to occur.

One of the causes for this is that the anode lattice undergoes volume expansion in the process of acid corrosion during use, which causes the entire lattice to deform, thereby forming voids between the active material and the lattice.

One method for solving this cause is to further improve the oxidation resistance of the lattice alloy. By improving the oxidation resistance, it is possible to suppress the oxidation of the anode grid and suppress the deformation due to the volume expansion of the grid.

Regarding this, it has been found that increasing the tin concentration in the lead-calcium-tin alloy within the range of 2.0% is an effective means.

[0008]

However, the problem of improving the corrosion resistance of the grid of the lead-acid battery, especially the anode grid, is universal, and the present invention also expands the cold-rolled sheet of lead-calcium alloy. It is an object of the present invention to further improve the corrosion resistance of the battery used as the anode and consequently provide a battery having a long life.

[0009]

[Means for Solving the Problems] As a method for solving this problem, an alloy obtained by adding bismuth as a new element to a lead-calcium-tin alloy is used as a conventional cold-rolled sheet, which is expanded. It is processed and used.

That is, the lead-acid battery of the present invention has a calcium content of 0.
A lead alloy containing 0.05 to 0.09%, tin 0.60 to 1.80%, and bismuth 0.005 to 0.05% is cold-rolled to form a sheet, and then expanded to form a grid body. It is characterized in that it is used for at least an anode.

[0011]

[Function] The corrosion resistance can be improved by adding bismuth as a new element to the lead-calcium-tin alloy.
The effect is synergistic with the effect of improving corrosion resistance by adding tin. As a result, the corrosion of the expanded anode grid is reduced, and the battery life can be improved.

The reason why the corrosion resistance can be improved by adding bismuth is considered as follows. That is, the cold-rolled sheet of lead-calcium-tin alloy is rolled to form a fine structure. This fine structure is a structure with excellent corrosion resistance, but when further secondary mechanical processing such as expanding processing is performed, the stress due to this processing causes coarse crystal structure that is easily corroded later. However, it is presumed that the addition of bismuth brings about an effect of suppressing the formation of a structure easily corroded after the secondary machining even if the secondary machining is performed.

[0013]

The present invention will be described with reference to the following examples.

Continuous slabs of various composition ratios having a thickness of 10 mm and a width of 80 mm were prepared from a lead-calcium-tin-bismuth alloy and cold rolled into sheets.

Table 1 shows the results of the life test of the battery using the expanded lattice of these alloys as the anode. As the life test, the SAE life test was performed at 75 ° C. so that the lattice elongation was in the deterioration mode of the battery. Also, the battery is 5
The evaluation was performed using a type battery having a time capacity of 48 Ah.

[0016]

[Table 1] As is clear from Table 1, the tin content is 0.60% to 1.
When it is 80%, the number of lifespan increases as bismuth is added, and 0.005% or more has the effect of extending the life,
When the amount of bismuth added exceeds 0.10%, the life becomes saturated. Therefore, the addition amount of bismuth is 0.005% to 0.
A range of 05% is suitable. Also, the amount of tin added is 0.6
The reason for limiting the content to 0% to 1.80% is that the life is shortened when the content is less than 0.6% or exceeds 1.8%.
When the amount of calcium is less than 0.05%, the mechanical strength of the lattice is low, and when it exceeds 0.09%, the amount of corrosion of the lattice increases, resulting in a shortened life.
A value between ˜0.09% was suitable. Table 1 shows the number of life tests, together with the results of examining the life test by stopping the life test at 2400 times and disassembling the battery to determine what percentage of the anode grid was oxidatively corroded.

From these results, it can be seen that there is a close relationship between the number of lifespan of the above life test and the oxidation resistance of the lattice.

From the above results, as the addition amount of the element, the amount of calcium is 0.05% to 0.09%, and the amount of tin is 0.
60% to 1.80%, the amount of bismuth is 0.005% to
Between 0.05% is considered suitable.

In addition, this kind of lead-calcium alloy is used in the alloy preparation by several hundreds p to stabilize the calcium concentration.
Although it is widely practiced to add pm of aluminum, the present invention is of course effective for such alloys.

[0020]

INDUSTRIAL APPLICABILITY As described above, the present invention remarkably improves the life characteristics of a calcium battery, and its industrial value is great.

Front page continuation (72) Inventor Nobuyuki Takami 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. Calcium 0.05 to 0.09%, tin 0.60 to 1.80%, and bismuth 0.005 to 0.0.
A lead storage battery, characterized in that a lead alloy containing 5% is cold-rolled to form a sheet, and further expanded lattice is used for at least an anode.