JPH06215794A - Thin type sealed storage battery - Google Patents

Abstract

PURPOSE:To provide a thin type sealed storage battery capable of minimizing the difference in reduction of electrolyte between cells and extending the life. CONSTITUTION:Cells 2 formed enclosing electrode plate groups are laminated in a battery jar 1 consisting of a film or sheet synthetic resin body, and the whole body of the group of the laminated cells 2 is housed in a metal case 4, and pressurized by the metal case 4 in the laminated direction to constitute a thin type sealed storage battery. A metal plate 3 larger than the contact area to the cell 2 is interposed between the adjacent cells 2 of such a thin type sealed storage battery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a thin sealed storage battery such as a thin sealed lead storage battery.

[0002]

2. Description of the Related Art Conventionally, this type of thin sealed storage battery has been
In a battery case made of a film- or sheet-shaped synthetic resin body, an electrode plate group consisting of an anode plate, a cathode plate and a separator is wrapped, and an electrolyte solution is injected into the battery case to form a single cell, The single cells are stacked, and the entire group of the stacked single cells is housed in a metal case, and the assembled battery is pressed by the metal case in the stacking direction.

[0003]

However, when the thin sealed storage battery having such a structure is used at a high temperature, variations in charge / discharge characteristics between cells due to a difference in reduction in electrolytic solution between cells poses a problem. Is coming. That is, in the single cell that is in contact with the metal case and the inner single cell that is not in contact with the metal case, the inner single cell has a greater decrease in the electrolytic solution than the single cell that is in contact with the metal case.

The cause of this is not clear, but because the inner unit cells have poorer adhesion between the cells than the unit cells of which one side is a metal case, or due to the stacking deviation between the cells, the atmosphere of the inner unit cells is different. It is thought that this is because the exposed area of the electrolyte increases and the electrolyte decreases due to moisture permeation.

In a single cell with a large decrease in electrolyte, the capacity decreases, the capacity of the entire assembled battery decreases, and the voltage rises at the end of charging early during charging, causing heat generation due to the oxygen absorption reaction of the cathode plate. In many cases, the battery pack as a whole tends to be overcharged, and in the worst case, the current runs into a thermal runaway state in which the current does not decrease at the end of charging, and the battery life ends early.

[0006] Such a thin sealed storage battery is mainly used as a power source for portable equipment, but the portable equipment is often used in a high temperature state, and an uninterruptible power supply (UPS) or the like is used. It may be installed inside a device that has a relatively high temperature.

An object of the present invention is to provide a thin sealed storage battery which can reduce the difference in decrease of the electrolytic solution between cells and can have a long life.

[0008]

The structure for achieving the above object will be described. The present invention is a unit cell formed by enclosing an electrode plate group in a battery case made of a film-shaped or sheet-shaped synthetic resin body. In a thin sealed storage battery in which the entire group of the stacked single cells is housed in a metal case and is pressed from the stacking direction by the metal case, between the adjacent single cells. Is characterized in that a metal plate larger than the contact area with the unit cell is interposed.

[0009]

When a metal plate having an area larger than the contact area with respect to the single cell is interposed between the adjacent single cells, all the single cells come into contact with the metal plate or the metal case, and between the metal plate or the metal case and the single cell. Good adhesion is obtained, and the difference in the decrease of the electrolytic solution due to moisture permeability is reduced.

[0010]

1 shows an embodiment in which the present invention is applied to a thin sealed lead-acid battery. In this thin sealed lead-acid battery, a separator mainly composed of glass fibers is interposed between an anode plate and a cathode plate (not shown) to constitute an electrode plate group, and the electrode plate group is made of a synthetic material having acid resistance and heat welding property. A single cell 2 is formed by enclosing and sealing a battery case 1 made of a resin film or sheet, and injecting an electrolytic solution into the battery case 1. The unit cells 2 are stacked via a metal plate 3 such as a stainless plate. The metal plate 3 has a shape larger than the contact area with the unit cell 2.
The whole group of the unit cells 2 stacked with the metal plate 3 interposed therebetween is housed in a metal case 4 made of stainless steel or the like, and is pressed by the metal case 4 in the stacking direction to form a battery pack structure. Has become.

In this way, the metal plate 3 is provided between the adjacent single cells 2.
Between the thin sealed lead acid battery of the present invention (the present invention product) in which the metal sheet 3 is interposed, and the conventional thin sealed lead acid battery (the conventional product) in which the metal plate 3 is not interposed between the adjacent single cells 2. In order to compare the difference in the decrease of the electrolytic solution, the product of the present invention and the conventional product were left at high temperature. The standing temperature is 71 ° C. The conventional product has a structure in which the metal plate 3 is removed from the product of the present invention, and other parts are exactly the same.

FIG. 2 shows the electrolyte reduction characteristics of the product of the present invention and the conventional product. As shown in the figure, in the conventional product, the amount of decrease in the electrolytic solution in the inner cell is larger than that in the cell in contact with the outer metal case, and there is a range in the amount of decrease in the electrolytic solution. The difference in the amount of decrease in the electrolytic solution was small, and the effect was recognized.

The present invention is not limited to the thin sealed lead-acid battery, but can be similarly applied to other sealed lead-acid batteries.

[0014]

As described above, in the thin sealed storage battery according to the present invention, since the metal plate having the area larger than the contact area with respect to the single cells is interposed between the adjacent single cells, all the single cells are disposed. Touches the metal plate or metal case, and good adhesion can be obtained between the metal plate or metal case and the unit cell.
It is possible to reduce the difference in the decrease in the electrolytic solution due to moisture permeation. Therefore, according to the thin sealed storage battery according to the present invention,
The variation in charge / discharge characteristics among cells can be reduced, the thermal escape phenomenon can be prevented, and the life can be extended.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a thin sealed storage battery according to the present invention.

FIG. 2 is a characteristic diagram showing reduction in electrolyte at high temperature between a thin sealed lead acid battery to which the present invention is applied and a conventional thin sealed lead acid battery.

[Explanation of symbols]

 1 Battery case 2 Single cell 3 Metal plate 4 Metal case

Claims (1)

[Claims] 1. A single cell formed by enclosing an electrode plate group in a battery case made of a film-shaped or sheet-shaped synthetic resin body, and the whole group of the stacked single cells is a metal case. In a thin sealed storage battery housed inside and being pressed from the stacking direction by the metal case, metal plates having a contact area larger than the contact area with the unit cells are interposed between the adjacent unit cells. A thin sealed storage battery characterized in that