JPH07134973A - Sealed lead-acid battery - Google Patents

Abstract

PURPOSE:To facilitate insertion of a group of electrode plates into a battery case so as to improve battery assembly efficiency and to reduce dispersion of battery characteristics by providing a hollow part vertically penetrating the battery case in the part parallel. to the electrode plate among barrier walls. CONSTITUTION:Among barrier walls 5, in the first, the third, and the fifth barrier walls 5 from the short side face 4A of a battery case 1, a hollow parts 6 vertically penetrating the battery case are arranged, and the thickness of both faces 5A, 5B of the barrier wall 5 facing the hollow part 6 are thinner than the thickness of the face 4A of the outer circumferential wall. When the inside of the storage battery is turned into a decompression condition, the surface facing the part 6 in the wall 5 is brought into contact with the atmosphere, so that a differential pressure P works between the inside of the storage battery and the part 6. Therefore, the odd numbers walls 5 from the outer circumference wall face 4A are bent by the differential pressure P, while they always press the respective group of electrode plates 2 with constant force. As the wall 5 is thinner than the face 4A and is easily deformed, the outer circumference wall is not bent. Therefore, battery can be provided with stable characteristics while its life can be greatly prolonged, even when thickness of a separator has some errors.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a sealed lead acid battery.

[0002]

2. Description of the Related Art In a sealed lead-acid battery, the oxygen gas generated from the anode side during charging during use is absorbed by the cathode plate to suppress hydrogen gas generation from the cathode side, resulting in excessive pressure in the battery. Is being prevented. Therefore, a gap that serves as a passage for the oxygen gas is required between the bipolar plates in addition to the electrolytic solution. For this reason, the electrolytic solution is impregnated into the separator in such a state that the electrolytic solution does not exude so that continuous voids as gas passages exist between the fibers inside the separator. As a result, the resistance value between the electrode plates changes significantly depending on the degree of contact between the separator and the electrode plate surface, which appears as a change in battery characteristics.

As described above, in the sealed lead-acid battery, unlike the conventional lead-acid battery having a fluid, the degree of pressure between the separator and the electrode plate surface is the most important factor affecting the characteristics.
Moreover, since the degree of pressure differs depending on the shape of the battery case and the position of the cell in the monoblock battery case, there is always a difference in characteristics between the cells. Therefore, in the sealed lead-acid battery, a retainer mat made of elastic glass fiber is used as a separator, and the electrode plate group is inserted into the battery case while pressing the separator with the electrode plate.

However, if the electrode plate group is inserted into the battery case under a too high degree of pressure, the electrode plate group may be damaged or the active material may penetrate the separator to induce a short circuit, so that the upper limit of the pressure degree is required. Is specified. For example, the thickness of the separator is 1/1
If the thickness is 0, the degree of pressure may be too high to insert the electrode plate group into the battery case. On the other hand, the separator contracts when it absorbs the electrolyte, so its pressure is 1 /
It drops sharply to 5 to 1/10 or less. For example, if the thickness of the separator is reduced to 1/10, the degree of compression between the electrode plates may become zero in the electrolytic solution-impregnated state. Therefore, the thickness of the separator cannot be easily changed. Further, the elasticity of the separator also deteriorates with age. For this reason, it is difficult to make the degree of compression applied to the electrode plates in the sealed lead-acid battery uniform, and this causes a large variation in the characteristics such as life.

It is known that even a sealed lead-acid battery constituted by a single cell can obtain much more stable characteristics than a side-to-side type monoblock cell. This is because the cathode plate absorbs the generated gas in the sealed lead acid battery as described above, so there is always a reduced pressure state and there is a differential pressure between it and the atmospheric pressure. This is because the electrode group is bent and pressed, whereas in the latter case, the intermediate cell is not pressed by the differential pressure.

For example, the internal pressure of the sealed battery may drop to 0.2 to 0.3 atm. In this case, since the differential pressure is 0.7 atm, the area of one side wall of the battery case is 10 cm × 10 cm.
= 100 cm ² , a load of 70 kg is applied to the side wall surface of the battery case. As described above, in the sealed battery having the single cell structure, the electrode plate surface and the separator can be stably contacted with the help of the very large differential pressure, and the stable discharge characteristic is obtained.

[0007]

On the other hand, in the case of a combination type monoblock battery case even in a sealed lead storage battery, if the battery container outer peripheral wall is made thin, the battery container outer peripheral wall bends inside the battery when decompressing. Therefore, it is known that the electrode plate group is uniformly pressed, but the curvature of the outer peripheral wall of the battery case is unattractive and impairs the marketability.

In the side-to-side monoblock battery case, a beam is provided on the short side surface and pressure is applied from the outer surface of the battery case. However, even the electrode plate group in the central cell is uniform. No pressure is applied, which causes variation in characteristics between cells. When the characteristics vary between cells like this,
As the battery as a whole is dominated by cells with low characteristics, the reliability of the battery is reduced.

For this reason, in the case of the conventional monoblock battery case, whether it is the combination type or the side-to-side type, the pressure applied to the electrode plate group had to depend on the elasticity of the separator. Therefore, as described above, after all, if the separator thickness changes even a little, if the error is in the positive direction, the electrode plate group cannot be inserted into the battery case. This resulted in a decrease in battery performance due to a decrease in pressure after injection.

The object of the present invention is to facilitate the insertion of the electrode plate group into the battery case to improve the battery assembly efficiency, and to uniformly press the electrode plate group after injecting the electrolytic solution regardless of the thickness of the separator. Is to reduce variations in battery characteristics.

In the present invention, the side-to-side type is a type in which all partition walls are formed parallel to the electrode plate surface as shown in FIG. 1, and the combination type is as shown in FIG. In addition, a mold formed of a partition wall parallel to the electrode plate surface and a partition wall perpendicular to the electrode plate surface.

[0012]

In order to achieve the object, the sealed lead acid battery of the present invention has a plate group inserted into each cell of a monoblock battery case partitioned by a partition into a plurality of cells. According to another aspect of the present invention, a hollow portion is provided in a portion of the partition wall that is parallel to the electrode plate so as to penetrate vertically in the battery case.

In this case, it is preferable that the partition wall facing the hollow portion is thinner than the outer peripheral wall of the battery case. As a typical embodiment of the present invention, a battery in which a monoblock battery case is composed of 6 cells arranged side-to-side and a hollow part is provided in an odd-numbered partition wall counted from the end, Another example is a battery in which a monoblock battery case is composed of 6 cells arranged in a combination type, and hollow portions are provided in all partition walls parallel to the electrode plate.

[0014]

In the sealed lead acid battery, the oxygen gas generated during charging is absorbed by the cathode plate as described above, so that the cathode plate is always in a depressurized state during use, and there is a pressure difference from the atmospheric pressure. Therefore, the partition wall and the outer peripheral wall of the battery case facing the hollow portion communicating with the outside air are curved inward due to the differential pressure. Since the partition wall facing the hollow portion is parallel to the electrode plate, it simultaneously presses the outer wall parallel to the electrode plate and presses the electrode plate group from both sides substantially uniformly. In this respect, unlike the conventional sealed lead-acid battery that depends only on the elasticity of the glass mat for the degree of pressure, the degree of pressure on the electrode plate group is not affected by the thickness error of the separator and the secular change of elasticity of the glass mat.

That is, since the differential pressure between the inside and outside of the storage battery, which is higher than the elasticity of the glass mat, is applied to the electrode plate group, the degree of pressure on the electrode plate group is the above-mentioned differential pressure regardless of the thickness error of the separator and the aging of the glass mat. Depends on. Therefore, the variation in the characteristics between the cells is small, and the characteristics of the entire battery are stable. If the thickness of the partition wall facing the hollow portion is made thinner than the thickness of the outer peripheral wall of the battery case, the partition wall is preferentially curved more largely than the outer peripheral wall, and therefore the commercial appearance is not impaired.

When the monoblock battery case is composed of 6 cells arranged side-to-side, all partition walls are parallel to the electrode plate, but only the odd-numbered partition walls counted from the end are hollow. When the parts are provided, the same differential pressure is generated in each cell, so that the variation between cells is almost eliminated. Further, when the monoblock battery case is composed of 6 cells arranged in a combination type, if all the partition walls parallel to the electrode plate, that is, the partition walls in the long side direction are provided with hollow portions,
Since the same differential pressure is generated in each cell, variations among cells are almost eliminated.

[0017]

【Example】

-Example 1- Hereinafter, the present invention will be described with reference to specific examples. Figure 1
FIG. 4 shows a battery case portion of a sealed lead acid battery according to the first embodiment of the present invention.

FIG. 1 (A) is a plan view of the battery case, FIG. 1 (B).
1A is a cross-sectional view taken along line AA in FIG. 1A, in which a one-dot chain line portion is a battery lid and shows a sealed state having a sealing function.

In the figure, the sealed lead-acid battery comprises a monoblock battery case 1, an electrode plate group (two-dot chain line portion) 2 and a battery lid 3. The monoblock battery case 1 has No. 5 partition walls 5 parallel to the short side surface 4A of the outer peripheral wall thereof. It is divided into 6 cell spaces 1 to 6, and the cells are arranged side to side. Then, the electrode plate group 2 is inserted into each cell in parallel with the short side surface 4A of the outer peripheral wall and connected in series by a conductor (not shown). Of the partition walls 5, the short side surface 4 of the battery case 1
1st, 3rd and 5th bulkheads 5 counting from A
Is provided with a hollow portion 6 penetrating vertically in the battery case,
The thickness of both sides 5A, 5B of the partition wall facing the hollow portion 6 is smaller than the thickness of the short side surface 4A of the outer peripheral wall. The battery lid 3 is provided with a function necessary for constructing a sealed lead-acid battery, for example, a check valve 7 that allows gas to flow out from the inside only when the internal pressure rises, and is well-known for adhesion, welding, etc. to the upper part of the battery case 1. It is fixed by the fixing means.

When the inside of the storage battery is in a depressurized state, the surface of the partition wall 5 facing the hollow portion 6 comes into contact with the atmosphere, so that a differential pressure P acts between the inside of the storage battery and the hollow portion 6. Therefore, the odd-numbered partition walls 5 counting from the short side surface 4A of the outer peripheral wall are curved by receiving the differential pressure P and press the respective electrode plate groups 2 with a constant force. Moreover, since the partition wall 5 is thinner than the short side surface 4A of the outer peripheral wall and is easily deformed, the outer peripheral wall is not curved. Therefore, the commercial appearance is not impaired. In the figure, the curved dotted line portions 8A and 8B are the partition wall surfaces 5 facing the hollow portion 6.
It shows the case where A and 5B are in a reduced pressure state.

On the other hand, in the conventional battery case, the partition wall 5 is not provided with the hollow portion 6. Therefore, in a sealed lead-acid battery in a depressurized state, no matter what tough resin material is used, the short side surface 4A always bends inward of the battery and stops when the pressure level of the electrode plate group 2 is balanced. Moreover, since the above-mentioned differential pressure is absorbed by the elastic contraction of the separators of the cells at both ends, the partition wall 5 does not bend. Therefore, the cell Nos. 1, 6 and the central cell No. 2 to 5 differ in the degree of pressure applied to the electrode plate group. As a result, the characteristics vary between cells. Since the characteristics of the entire battery are dominated by the characteristics of the inferior cell, the battery performance must be inferior in the end. Moreover, since only the short side surface 4A of the outer peripheral wall receives all of the above-mentioned differential pressure, the outer peripheral wall may be damaged.

In this example, the hollow portion 6 of the partition wall 5 has a cell No. 1 and cell No. 1 2, cell number. 3 and cell No. 3
4, cell no. 5 and cell number. 6 is provided between the cells No. 6 and No. 2 and cell No. 3, cell No. 4 and cell No. 4 It may be provided between the five. Alternatively, the hollow portions 6 may be provided in the partition walls 5 at five locations between the cells.

Example 2 FIG. 2 shows a sealed lead acid battery according to a second example of the present invention. FIG. 2A is a plan view of a 6-cell monoblock battery case arranged in a combination type, FIG.
2B is a cross-sectional view taken along line BB when the electrode plate group is inserted into the battery case of FIG. 2A and the battery lid is covered to complete the battery.

The sealed lead-acid battery comprises a monoblock battery case 1, an anode plate 2A, a cathode plate 2B and an electrode plate group 2 composed of a separator 2C between both electrodes, and a battery lid 3. The monoblock battery case 1 has No. 6 partition walls 5 parallel to the short side surface 4A or the long side surface 4B of the outer peripheral wall thereof. It is divided into 6 cell spaces 1 to 6, and the cells are arranged in a combination type. Then, the electrode plate group 2 is inserted into each cell in parallel with the long side surface 4B of the outer peripheral wall and connected in series by a conductor (not shown). Electrodes 2A and 2B of the partition wall 5
All of the partition walls 5 parallel to each other are provided with hollow portions 6 penetrating vertically in the battery case. The thickness of both side surfaces 5A and 5B of the partition walls 5 facing the hollow portions 6 is the long side surface of the outer peripheral wall. It is thinner than the thickness of 5B. The battery lid 3 is fixed to the upper part of the battery case 1 with a function necessary for constructing a sealed lead-acid battery, for example, a check valve 7 that allows gas to flow out from the inside only when the internal pressure rises.

The sealed lead-acid battery of this example has the characteristics of a general sealed battery, and the oxygen gas generated in the battery is absorbed by the cathode plate, so that the internal pressure of the battery does not change during normal use of the charge / discharge cycle. About 0.5 atm, the generated gas is completely absorbed by the cathode plate when left to stand, so that the pressure drops to about 0.2 atm. Even if the internal pressure is 0.5 atm, the differential pressure from the atmosphere is 0.5 atm, and assuming that the area of the long side surface 4B of the battery is 10 cm × 10 cm = 100 per cell, 50 kg.
A heavy load is applied to the long side surface 4B.

When the inside of the storage battery is depressurized in this way, the surface of the partition wall 5 facing the hollow portion 6 comes into contact with the atmosphere, so that a differential pressure P acts between the inside of the storage battery and the hollow portion 6. Therefore, the partition wall 5 parallel to the long side surface 4B of the outer peripheral wall is bent by the differential pressure P (one-dot chain line portion in the figure) and presses each electrode plate group 2 with a constant force. The degree of pressure due to the differential pressure P is 10 times or more than the degree of pressure due to only the elasticity of the separator even if the partition wall 5 having the hollow portion 6 is curved by 1 mm, so a rigidly deformed battery case was used. It provides much more stable discharge characteristics than a sealed lead acid battery. Moreover, since the partition wall 5 is thinner and more easily deformed than the long side surface 4B of the outer peripheral wall, the outer peripheral wall is not curved. Therefore, the commercial appearance is not impaired.

On the other hand, in the conventional battery case, the partition wall 5 is not provided with the hollow portion 6. Therefore, in a sealed lead-acid battery in a depressurized state, no matter what tough resin material is used, the long side surface 4B is always curved inward of the battery and stops when the pressure level of the electrode plate group 2 is balanced. Therefore, the commercial appearance of the battery is greatly impaired.

[0028]

Since the sealed lead-acid battery of the present invention has the above-mentioned structure, it exerts a great effect as follows.

(1) Due to the pressure difference between the inside and the outside of the battery, the partition wall provided with the hollow portion can be deformed / curved to constantly press the electrode plate group. Therefore, even if there is an error in the separator thickness, stable characteristics and a significant prolongation of life can be obtained.

(2) Since the partition having the hollow portion is preferentially deformed, the outer peripheral wall of the battery case can be prevented from being deformed at all.
This made a great contribution to improving the appearance of the product. (3) Since it is not necessary to rely on the pressure of the glass mat, the electrode plate group can be easily inserted into the battery case, and the workability in assembling is significantly improved.

(4) Since the hollow portion penetrates up and down the battery case, the mold for molding the hollow portion can be fixed at both ends when the battery container is injection molded. Therefore, it is possible to prevent damage and deformation of the thinnest part of the mold.

[Brief description of drawings]

FIG. 1 shows a battery case of a sealed lead-acid battery according to a first embodiment, (A) is a plan view of the battery case, and (B) is AA of (A).
It is sectional drawing cut | disconnected along the line.

FIG. 2 shows a sealed lead acid battery according to a second embodiment,
(A) is a plan view of the battery case, and (B) is a cross-sectional view taken along line BB in the case where the electrode plate group is inserted into the battery container of (A) and the battery cover is covered to complete the battery.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Monoblock battery case 2 ... Electrode plate group 2A ... Anode plate 2B ... Cathode plate 2C ... Separator 3 ... Battery lid 4 ... Battery container outer peripheral wall 4A ... Short side surface of battery container outer peripheral wall 4B ... Long surface of battery container outer peripheral wall 5 ... Partition walls 5A, 5B ... Both side surfaces of the partition wall having a hollow part 6 ... Hollow part 7 ... Check valve 9 ... Connection rod position 10 ... Fixed part

Claims (4)

[Claims] 1. A sealed lead acid battery in which an electrode plate group is inserted into each cell of a monoblock battery case partitioned into a plurality of cells by a partition wall, wherein a battery case is provided in a portion of the partition wall parallel to the electrode plate. A sealed lead-acid battery characterized in that it has a hollow portion that penetrates vertically. 2. The sealed lead-acid battery according to claim 1, wherein the partition wall facing the hollow portion is thinner than the outer peripheral wall of the battery case. 3. The monoblock battery case is composed of 6 cells arranged side by side, and a hollow portion is provided in an odd-numbered partition wall counted from the end. Sealed lead acid battery. 4. The monoblock battery case is composed of 6 cells arranged in a combination type, and hollow portions are provided in all partition walls parallel to the electrode plate.
The sealed lead acid battery according to.