JPH04328269A - Sealed type lead-acid battery - Google Patents

Abstract

PURPOSE:To prevent lowering of battery performance to be caused by generation of clearance between a positive electrode plate and a negative electrode plate by pressing a foaming resin plate to projecting parts provided in four sides of the side surfaces inside of a battery jar for abutment, and pressing the top surface of the powder material. CONSTITUTION:A foaming resin plate 4 has acid resistance and passes gas and electrolyte but not the powder material 3. This plate 4 is foamed outside of a battery and is formed into plate, and when the pressure more than a constant pressure is applied to this plate 4, it is deformed, and is not returned to the original shape. The plate 4 is inserted from the top surface of a battery jar 1, and is made to abut on projecting parts 5 provided in the four sides of the side surfaces inside of the battery jar 1. When the plate 4 is inserted furthermore, the plate 4 is inserted forcedly to be deformed into the shape of the projecting parts 5, and is made to abut on the top surface of the powder material 3 filled inside of a battery. Blow-up of the powder material 3 at the time of the charge is thereby prevented to prevent lowering of battery performance.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in sealed lead-acid batteries.

0002

BACKGROUND OF THE INVENTION There are two types of sealed lead-acid batteries in which the negative electrode absorbs oxygen gas generated during charging of the battery: a retainer type and a gel type. In the retainer type, a matte separator (glass separator) mainly made of fine glass fibers is inserted between the positive and negative electrode plates, and this holds the sulfuric acid electrolyte necessary for discharge and isolates the two electrodes. In recent years, it has been widely used as a backup power source for portable devices and computers due to its characteristics such as no maintenance, no leakage, and no position.

[0003] However, glass separators are made of fine glass fibers with a diameter of around 1 micron manufactured using a special method into a mat shape, and are considerably more expensive than separators for lead-acid batteries that are generally used. In addition, in order to obtain stable battery performance, the electrode plates must be strongly compressed and assembled, which makes assembly of the battery difficult and inevitably increases the manufacturing cost of the battery.

[0004] Furthermore, only the glass separator inserted between the positive and negative electrode plates can hold the sulfuric acid electrolyte, and the electrolyte cannot be kept around the electrode plates as in an open type lead-acid battery. Since the battery cannot be placed anywhere in the battery, the battery reaction is limited by the amount of electrolyte, which has the disadvantage that the battery performance is inferior to that of a liquid type battery.

On the other hand, gel type batteries are cheaper than cage type batteries, but their battery performance is inferior to that of cage type sealed lead acid batteries.
The drawback was that the electrolyte separated from the sulfuric acid gel during use, resulting in poor longevity.

[0006] In order to eliminate these drawbacks, sealed lead-acid batteries have been proposed that are neither retainer type batteries using fine glass fiber nor gel type batteries using a gel electrolyte. That is, a powder having high porosity and a large specific surface area, such as silica powder, is used as an electrolyte holding material, and the above powder is filled in the gap between the positive electrode plate and the negative electrode plate and around the electrode plate group. This is a sealed lead-acid battery.

[0007] Silica powder is an inexpensive material that is produced and sold in large quantities, and has excellent acid resistance and electrolyte retention ability, so it is a powder used as an electrolyte retaining material for this type of sealed lead-acid battery. It can be said that it is an excellent material. but,
In sealed lead-acid batteries that use this powder as an electrolyte holder, this powder moves to the top of the battery along with the electrolyte and gas generated from the electrode plates during charging, and is deposited between the positive and negative plates. It has been found that voids may occur, which may reduce battery performance.

Therefore, in order to suppress the movement of the powder, a porous thin sheet is placed on top of the powder, and a perforated resin plate with a plurality of holes is then forcibly inserted into the battery case. ,
Alternatively, foam the phenolic resin on top of the powder,
The silica powder was fixed. However, the method of using a thin porous sheet and a perforated resin plate in combination is complicated, and has the disadvantage that the perforated resin plate requires high dimensional accuracy because it is forced into the battery case.

[0009]

[Means for Solving the Problems] The present invention fills the gap between the positive electrode plate and the negative electrode plate and the periphery of the electrode plate group with powder having high porosity and large specific surface area.
The problem with sealed lead-acid batteries in which the powder is substantially impregnated with a sufficient amount of sulfuric acid electrolyte is that the powder moves to the top of the battery along with the electrolyte and gas generated from the electrode plates during charging. This prevents air gaps from forming between the positive electrode plate and the negative electrode plate, which degrades battery performance. The purpose is to press against the convex portions provided on the four circumferences of the side surface and press against the upper surface of the powder.

0010

EXAMPLES The present invention will be explained below based on examples. FIG. 1 is a cross-sectional view of the main parts of a sealed lead-acid battery according to the present invention, in which a battery case 1 is inserted with a plate group 2 consisting of a positive plate, a negative plate, and a separator. The gap and the periphery of the electrode plates are filled with powder 3 having high porosity and large surface area.

[0011] Since this powder 3 has high porosity and a large surface area, it can strongly hold a large amount of electrolyte. In this example, silica powder was used. This powder 3
A foamed resin board 4 is pressed onto the top of the board.

[0012] This foamed resin plate 4 must have acid resistance and allow gas and electrolyte to pass therethrough, but not the powder 3. Here, a foamed phenolic resin board was used. This foamed phenolic resin plate 4 is formed into a plate shape by foaming outside the battery, and when pressure above a certain level is applied, it deforms and hardly returns to its original shape. Further, although the foamed resin plate 4 which is slightly smaller than the top surface of the battery case 1 is used here, a plate having the same size as the top surface of the battery case 1 may be forcibly inserted and pressed.

This foamed resin plate 4 is inserted from the upper surface of the battery case 1 and comes into contact with the convex portions 5 provided on the four circumferences of the inner surface of the battery case 1. The convex portion 5 can be formed into a cross-sectional shape as shown in FIG. Figure 2 (B) after filling
) may be pasted onto a predetermined position. When the foamed resin plate 4 is further pushed in, it is forcibly inserted while deforming into the shape of the convex portions 5 provided on the four circumferences of the inner surface of the battery case 1, and comes into contact with the upper surface of the powder 3 filled in the battery. At the position where it is pressed against the upper surface of the powder 3, the foamed resin plate 4 must be in contact with the convex portions 5 provided on the four circumferences of the inner surface of the battery case 1. In this way, the foamed resin plate 4 is pressed against the upper surface of the powder 3 filled in the battery. In this example, we used a foamed resin plate that was foamed outside the battery, cut into a predetermined shape, and molded, so it was possible to remove the skin layer that is impermeable to the electrolyte and gas that is produced during foaming, and the inner surface of the battery case. Since the foamed resin plate is pressed against the convex portions provided on the four circumferences of the foamed resin plate to be deformed and brought into close contact with the battery case, high dimensional accuracy is not required for molding the foamed resin plate.

[0014]

As described in detail above, according to the present invention, the disadvantages of the conventional method can be solved by simply providing a protrusion on the inner surface of the battery case and pressing the powder while pressing a foamed resin plate onto the protrusion. It can prevent body swelling and has great industrial value.

[Brief explanation of drawings]

[Fig. 1] Cross-sectional view of essential parts of a sealed lead-acid battery according to the present invention

[Fig. 2] An explanatory diagram showing an example of a convex portion provided on the inner surface of the battery case according to the present invention.

[Explanation of symbols]

1 Battery case 2 Pole group 3 Powder 4. Foamed resin board 5.Protrusion 6 Lid

Claims (1)

[Claims] Claim 1: A powder having high porosity and a large specific surface area is filled in the gap between the positive electrode plate and the negative electrode plate and around the electrode plate group, and a sufficient amount of sulfuric acid electrolyte necessary for charging and discharging the battery is substantially applied. A sealed lead-acid battery impregnated and held in the powder,
A closed type, characterized by a foamed resin plate that allows gas and electrolyte to pass through but not the powder, which is pressed against the convex parts provided on the four circumferences of the inner surface of the battery case, and is forcibly inserted while pressing the top surface of the powder. Lead acid battery.