JPH07335183A - Sealed lead acid battery - Google Patents

Abstract

PURPOSE:To provide a sealed lead acid battery which has a long lifetime and is free from water reduction through a battery jar wall parallel with electrode plates even through a long period of service. CONSTITUTION:A sealed lead acid battery has battery jars 5, 10 and an electrode bunch 1 which is formed by stacking positive electrode plate 2 and negative electrode plates 3 with separators 4 interposed, wherein the negative electrode plates 3 are located at the two ends. Anti-acid metal foils 7, 12 are attached fast to the inside surfaces 6, 11 of the battery jar side walls 4, 14 which are parallel with the negative electrode plates 3. The metal foils 7, 12 are in contact with negative electrode plates 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed lead-acid battery used as a backup power source for computers, communication equipment and the like and a power source for electric tools and the like.

[0002]

2. Description of the Related Art A sealed lead-acid battery normally transfers oxygen gas generated in the positive electrode plate to the negative electrode plate at the end of charging to react with the negative electrode active material to consume the oxygen gas and bring the negative electrode plate into a discharged state. It is hermetically sealed by using a so-called "O ₂ cycle" that suppresses the generation of hydrogen gas from. However, the oxygen gas absorption efficiency of the negative electrode plate is completely 100%.
However, it is impossible to completely eliminate the generation of hydrogen gas from the negative electrode plate.Since hydrogen gas is generated not only at the end of charging but also during storage by self-discharge of the battery, release it into the atmosphere. It has a safety valve. At this time,
Moisture in the electrolytic solution is also released outside the battery system, and the amount of the electrolytic solution decreases.

In addition to the escape from the safety valve, the water content in the electrolytic solution is released into the atmosphere through the wall of the container, which causes an increase in internal resistance. The increase in the internal resistance deteriorates the discharge voltage characteristic, and the capacity cannot be taken out especially in the case of high rate discharge, and the decrease in the capacity is controlled by the amount of water reduction. Normal ABS (acrylonitrile
Although synthetic resins such as butadiene / styrene) and PP (polypropylene) are used, the water permeability is particularly high in the case of ABS resin.

In the case of a sealed lead-acid battery composed of a plurality of cells,
Each cell is partitioned by partition walls. There are roughly two methods, that is, a "eye" shape as shown in FIG. 9 and a "field" shape as shown in FIG. Among these, in the case of the "eye" shape, the difference in the surface area of the intermediate cell and the cells at both ends in contact with the atmosphere is large, so the water reduction amount of both end cells becomes larger than that of the intermediate cell, and when used for a long time The battery capacity becomes dominated by the cells at both ends. Of course, in order to improve the life of sealed lead-acid batteries that are used for a long period of time, not only in the case of such an "eye" shape,
Even in the case of the "rice field" shape, there is a problem, and it is necessary to reduce water reduction through this battery wall. In order to improve such a problem, in Japanese Unexamined Patent Publication No. 6-20661, a metal foil is arranged outside the side walls parallel to the partition walls of the cell chambers at both ends in the case of the above-mentioned "eye" shape. Is proposed.

[0005]

However, when the metal foil is arranged on the outside of the side wall, the water vapor that has permeated from the inside is accumulated between the metal foil and the resin battery case and pushes up the metal foil to lift it up. There was a problem that unevenness was formed on the surface and even peeled off in extreme cases. The present invention overcomes the above-mentioned problems, and an object of the present invention is to provide a sealed lead-acid battery with a long life, which does not reduce water through a battery case wall parallel to an electrode plate even when used for a long period of time. It is a thing. Furthermore, the present invention is a sealed type with a long life that does not reduce water through the battery case wall parallel to the electrode plate not only when the cells are partitioned in the shape of "eyes" but also in the shape of "fields". It is intended to provide a lead storage battery.

[0006]

In order to achieve the above object, the present invention is a sealed lead acid battery having a battery case 5 or 10 and a pole group 1, wherein the pole group 1 is a positive electrode plate. 2 and the negative electrode plate 3 are laminated via a separator 4, and the negative electrode plate 3 is provided at both ends, and the battery case 5 or 10 is parallel to the working surface of the negative electrode plate 3. Acid resistant metal foil 7 or 1 on the inner surface 6 or 11 of the side wall 8 or 14.
2 is integrated, and the metal foil 7 or 12 is in contact with the negative electrode plate 3. The metal foil 7 or 12 is preferably a foil containing lead as a main component, and the metal foil 7 or 12 is preferably integrated with the battery case 5 or 10 with a hot-melt adhesive. .

[0007]

Since the metal foils 7 and 12 are arranged on the inner surfaces 6 and 11 of the side walls of the battery cells 5 and 10 which are parallel to the electrode plates 2 and 3, the moisture in the electrolytic solution is provided by the shielding function of the foils 7 and 12. Does not dissipate to the outside of the battery through the side wall. Also, the foils 7, 1
Since 2 is inside the resin container, water vapor does not accumulate between the foils 7 and 12 and the resin container, and moreover, because it is pressed against the negative electrode plate 3, it is lifted from the resin container. There is no. Since the foil containing lead as a main component is harmless to the battery and has excellent corrosion resistance, it does not adversely affect the performance of the battery. Further, when the hot-melt adhesive is used to integrate the metal foils 7, 12 and the battery cases 5, 10, the metal foils 7, 12 can be integrated at the same time when the battery cases 5, 12 are molded.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a perspective view showing a state immediately before inserting a pole group into a battery case according to an embodiment of the present invention, in which 1 is two positive electrode plates 2 and three negative electrode plates 3 and A negative electrode plate 3 is disposed at both ends of the positive and negative electrode plates, which is a group of electrodes formed by arranging a separator 4 made of fine glass fiber. 5 is AB
It is a battery case made of S resin, and each cell is partitioned in a "rice field" shape, and a pure lead foil 7 having a thickness of about 200 μm is formed on the inner surface 6 of the side wall 8 parallel to the working surfaces of the electrode plates 2 and 3. It is attached with epoxy resin. Such a sealed lead-acid battery A of the present invention was produced. The thickness of the long side wall 8 of the battery case 5 is 1.
The thickness of the short side wall 9 was 0 mm, and the thickness of the short side wall 9 was 2.5 mm.

A sealed lead-acid battery B having the same structure as that of the sealed lead-acid battery A described above was prepared, but the pure lead foil was not adhered to the inner surface of the side wall of the battery case. . A float life test was carried out on these two sealed lead acid batteries at 50 ° C., and changes in capacity, water reduction and internal resistance were measured. The results are shown in FIGS. The test conditions are
It was carried out by constant voltage charging at 2.275 V / cell at an ambient temperature of 50 ° C., taken out every month, and confirming the 3C capacity at an ambient temperature of 25 ° C.

After the end of the test, the battery was disassembled to investigate the cause of the decrease in capacity. As a result, the sealed lead-acid battery A according to the present invention
In contrast, while the corrosion of the positive electrode grid was the cause of the capacity reduction, when the sealed lead-acid battery B of the conventional configuration was replenished with water corresponding to the water loss, the capacity was about 85% of the initial capacity. From the obtained results, it was judged that the capacity could not be taken out due to the increase of internal resistance due to the decrease of water content in the electrolytic solution.

(Embodiment 2) FIG. 5 is a perspective view showing a battery case according to another embodiment of the present invention. 10 is a battery container made of ABS resin, and each cell has a shape of "eye". The pure lead foil 12 having a thickness of about 200 μm is attached to the inner surface 11 of the side wall 14 which is partitioned and parallel to the working surface of the electrode plate (not shown) with a hot-melt adhesive to form the sealed lead-acid battery C according to the present invention. It was made.
The long side wall 13 of the battery case 10 has a thickness of 2.0 mm and the short side wall 14
Had a thickness of 2.0 mm. The pole group had the same configuration as in Example 1.

A sealed lead-acid battery D having a conventional structure, which has the same pole group structure and the same battery material as that of the above-mentioned sealed lead-acid battery C but has no lead foil attached to the inner surface of the side wall of the battery case, was manufactured. A float life test was carried out on these two sealed lead acid batteries at 50 ° C., and changes in capacity, water reduction and internal resistance were measured. The results are shown in FIGS. The test method is
This is the same as in the first embodiment. After the test was completed, the battery was disassembled to investigate the cause of the decrease in capacity. Sealed lead-acid battery C according to the present invention
In contrast, while the corrosion of the positive electrode grid was the cause of the capacity decrease, when the sealed lead-acid battery D of the conventional configuration was replenished with water corresponding to the water loss, the capacity was about 90% of the initial capacity. From the obtained results, it was judged that the capacity could not be taken out due to the increase in internal resistance due to the decrease in water content in the electrolytic solution.

The sealed lead-acid battery according to the first to second embodiments of the present invention has a long service life even if it is used for a long period of time, because its life is not controlled by water reduction through the wall of the battery case. It turns out that it is a storage battery. Moreover, in the case of the sealed lead-acid battery according to the present invention, the life is controlled by the water reduction through the battery case wall not only when the cells are partitioned in the shape of "eyes" but also when the cells are in the shape of "fields". It is clear from Example 1 that the product has a long life and does not occur.

In the examples, the method of arranging the foil containing lead as the main component on the inner wall of the battery case is shown by using an epoxy resin example and a hot melt adhesive, but the present invention is not limited to this. Absent. Especially in the case of using a hot-melt adhesive, it is applied on the surface of the metal foil in advance, and it is placed in the mold core part during the molding of the battery case, and then the battery container is molded by normal injection molding to achieve integration. It is easily possible. Further, in the case of an epoxy resin, the same effect can be obtained by applying it to the surface of the metal foil in the B stage state. At this time, if it is applied to both sides of the foil, direct contact with the negative electrode plate can be prevented and the risk of internal short circuit can be reduced, which is more effective.

In the case of the present invention, since the metal foil is arranged on the inner wall of the battery case, the adhesive strength between the battery case and the metal foil need not be so large. This happens when the metal foil is attached to the outer surface of the side wall, because the metal foil is placed inside the battery case, and the metal foil is pressed against the one surface by the parallel negative plate. This is because there is no fear that the foil will float or peel off, and there will be no problem in appearance. In order to obtain such an effect, in the sealed lead acid battery of the present invention, the metal foil must be arranged on the inner surface of the side wall of the battery case in parallel with the working surface of the negative electrode plate. This is because, if the metal foil is arranged in the direction perpendicular to the negative electrode plate, the metal foil is also arranged in the direction perpendicular to the positive electrode plate, and the possibility of causing a short circuit increases.

As the metal foil, an example of using pure lead was shown in the embodiment, but the present invention is not limited to this, and an alloy of lead and another metal such as Ca, Sn, Sb, aluminum or the like is used. It is possible. However, an alloy containing lead as a main component, particularly an alloy that can be used for a normal negative electrode grid, is preferable because it can reduce self-discharge and prevent abnormal corrosion. With respect to the thickness, an example in which the thickness is 200 μm is shown in the embodiment, but the present invention is not limited to this, and may be any thickness which is easy to integrate with the battery case and easy to handle. However, in order to reduce the risk of tearing during handling, 50
A thickness of up to 500 μm is suitable.

Although the thickness of the side wall of the battery case on the surface to which the metal foil is attached is the same as that of the conventional example in the embodiment, in the case of the present invention, the water reduction through the side wall is so small that it can be ignored, so the capacity of the battery is reduced. In order to increase the thickness, it can be made thinner than before, and the side wall thickness can be made as thin as 1.5 mm. In the examples, the example in which the ABS resin is used as the battery case material is shown, but the present invention is not limited to this. Even if a PP resin having a water permeability of about 1/3 to 1/10 that of an ABS resin is used, the water permeability of a foil containing lead as a main component is estimated to be 0. It is effective in improving the life of lead acid batteries.

[0017]

As described above in detail, according to the present invention, there is provided a sealed lead acid battery having a long life, which does not have its life controlled by water reduction through the side wall of the battery case even when used for a long time. It is possible. Further, according to the present invention, even when the partitioning of the cells is not only in the shape of "eye" but also in the shape of "field", the life is not controlled by the water reduction through the battery wall, and the life is long. It is possible to provide a sealed lead acid battery. Further, when a foil containing lead as a main component is used as the metal foil as in claim 2, the metal foil is excellent in corrosion resistance without self-discharge. Further, when the hot-melt adhesive is used to integrate the metal foil and the battery case as in claim 3, the battery container can be integrated at the same time when molding, and the manufacturing method is simplified.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state immediately before inserting a pole group into a battery case according to an embodiment of the present invention.

2 is a graph showing the life characteristics of the product of the present invention and the conventional product in Example 1. FIG.

FIG. 3 is a graph showing changes in internal resistance of the product of the present invention and a conventional product in Example 1.

FIG. 4 is a graph showing changes in the amount of water reduction of the product of the present invention and the conventional product in Example 1.

FIG. 5 is a perspective view showing a battery case according to another embodiment of the present invention.

FIG. 6 is a graph showing life characteristics of the product of the present invention and a conventional product in Example 2.

FIG. 7 is a graph showing changes in internal resistance of the product of the present invention and a conventional product in Example 2.

FIG. 8 is a graph showing changes in the amount of water reduction of the product of the present invention and the conventional product in Example 2.

FIG. 9 is a plan view showing an “eye” -shaped battery case.

FIG. 10 is a plan view showing a battery case having a “T” shape.

[Explanation of symbols]

 1 Pole group 2 Positive electrode plate 3 Negative electrode plate 4 Separator 5,10 Battery case 6,11 Side wall inner surface 7,12 Metal foil 8,9,13,14 Side wall

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Kitami 6-6 Josaimachi, Takatsuki City, Osaka Prefecture Yuasa Corporation

Claims (3)

[Claims] 1. A sealed lead acid battery having a battery case (5, 10) and a pole group (1), wherein the pole group (1) comprises a positive electrode plate (2) and a negative electrode plate (3). The negative electrode plates (3) are laminated on both sides with a separator (4) in between.
The battery case (5, 10) has an acid resistant metal foil (7, 7) on an inner surface (6, 11) of a side wall (8, 14) parallel to the negative electrode plate (3). 12) is integrated, and the metal foil (7, 12) is in contact with the negative electrode plate (3). A sealed lead acid battery. 2. The metal foil (7, 12) according to claim 1,
A sealed lead-acid battery, which is a foil containing lead as a main component. 3. The sealed lead acid battery according to claim 1, wherein the metal foil (7, 12) is integrated with the battery case (5, 10) with a hot-melt adhesive.