JPH05190200A - Sealed type alkaline storage battery - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent an internal short circuit from being caused by a metal burr of the base material on the cut surface of the positive electrode or the negative electrode penetrating the separator. [Structure] The peripheral portion of the positive electrode 1 and / or the peripheral portion of the negative electrode is covered with the heat-fusible resin 2 including the cut end face thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed alkaline storage battery using a spiral electrode body.

[0002]

2. Description of the Related Art In a sealed alkaline storage battery, a sheet-shaped positive electrode and a sheet-shaped negative electrode are spirally wound with a separator interposed therebetween to produce a spirally wound electrode body, and the spirally wound electrode body is used as a battery case. It is housed inside and the opening of the battery case is sealed and hermetically closed (for example, Japanese Patent Laid-Open No. 2-199768).

[0003]

However, since the positive electrode and the negative electrode used in the production of the spirally wound electrode body are long or wide ones cut into a predetermined size, they are On the cut surface of the electrode, a protrusion (so-called burr) of a constituent metal such as a metal mesh used as the base material is generated, and the metal burr penetrates the separator, causing an internal short circuit, and There is a problem that the characteristics are rapidly deteriorated.

[0004]

According to the present invention, by covering the peripheral portion of the positive electrode and / or the peripheral portion of the negative electrode also with the cut end face thereof with an alkali-resistant heat-fusible resin,
This prevents metal burrs on the cut end faces from penetrating the separator and causing an internal short circuit.

In the present invention, examples of the alkali-resistant heat-fusible resin used for coating the peripheral portion of the positive electrode and the peripheral portion of the negative electrode include modified polyethylene, modified polypropylene and modified ethylene-propylene copolymer. The film-like one is suitable for use.

The coating with the alkali-resistant heat-fusible resin is suitable for both the peripheral portion of the positive electrode and the peripheral portion of the negative electrode, but either the peripheral portion of the positive electrode or the peripheral portion of the negative electrode may be performed. Even if it is performed on one side, the burr of the other electrode does not enter into the electrode on the coated side, so that the occurrence of an internal short circuit can be prevented.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

Example 1 A slurry containing nickel powder as a main component was applied to both surfaces of a nickel porous plate, dried, sintered at about 1000 ° C. for 30 minutes, and then cooled to room temperature.

After impregnating this in a nitrate bath several times, it is neutralized, charged in an alkaline electrolyte, washed with water and dried, and then the obtained sheet material is cut into a predetermined size.
A sheet-shaped positive electrode was produced.

Then, as shown in FIG. 1, after a current collector piece 3 is attached to the sheet-shaped positive electrode 1, a modified polyethylene film including the cut end face thereof is heat-sealed to the peripheral portion of the positive electrode 1. The peripheral portion of the positive electrode 1, including the cut end face thereof, was covered with the heat-fusible resin 2.

Apart from this, the composition is Ti ₁₆ Zr ₁₆ V ₂₂ N
i ₃₃ Cr ₇ hydrogen-absorbing alloy powder was rolled together with a plain weave nickel net as a base material, sintered at about 1000 ° C. for about 30 minutes, and cooled to room temperature, and then the obtained sheet-shaped product was made to have a predetermined size. The sheet was cut into a sheet-shaped negative electrode.

Then, as shown in FIG. 2, after the collector piece 6 is attached to the negative electrode 4, a modified polyethylene film including the cut end face thereof is heat-sealed to the peripheral edge portion of the negative electrode 4 to form a negative electrode 4. The peripheral edge portion of was also coated with the heat-fusible resin 5 including the cut end surface.

The positive electrode 1 and the negative electrode 4 are spirally wound with a separator interposed therebetween to form a spiral electrode body, and the spiral electrode body is housed in a battery case. The sealed alkaline storage battery shown in 3 was assembled.

Explaining the battery shown in FIG. 3, 1 is a positive electrode, 3 is a current collecting piece, 4 is a negative electrode, and 6 is a current collecting piece.
7 is a separator. In FIG. 3, since the detailed portion cannot be illustrated due to a space limitation, the heat-melting resins 2 and 5 described above are not illustrated.

The positive electrode 1 and the negative electrode 4 are sheet-shaped, and as described above, they are spirally wound with the separator 7 interposed therebetween to form a spiral electrode body, which is housed in the battery case 8. The end of the current collecting piece 6 has the battery case 8
Spot welded to the bottom of the.

In addition to the above materials, an insulating material 9 is arranged at the bottom of the battery case 8, and an electrolytic solution composed of an aqueous solution of potassium hydroxide is injected to the insulating material 10 on the spirally wound electrode body. It is arranged.

A sealing lid 12 is arranged in the opening of the battery case 8 via an annular gasket 11, and the opening of the battery case 8 is sealed by caulking the opening edge of the battery case 8 inward. It is designed so that the sealed state is maintained.

However, the sealing lid 12 is provided with a vent which operates when a large amount of gas is generated inside the battery and the internal pressure rises abnormally to release the gas inside the battery to the outside to prevent the battery from bursting. The mechanism is adopted.

The upper portion of the sealing lid 12 functions as an electrode terminal, and the lower portion of the sealing lid 12 and the positive electrode 1 collect the current collecting piece 3.
Are electrically connected by.

When 100 batteries of this Example 1 were produced and examined for the occurrence of internal short circuit, no internal short circuit occurred.

[0021]

As described above, according to the present invention, the peripheral portion of the positive electrode and / or the peripheral portion of the negative electrode is coated with the alkali-resistant heat-fusible resin, including the cut end face thereof, to thereby improve the internal performance. It was possible to prevent the occurrence of a short circuit.

[Brief description of drawings]

FIG. 1 is a plan view showing a state in which a current collector piece is attached to a positive electrode and a peripheral portion of the positive electrode is covered with an alkali-resistant heat-fusible resin.

FIG. 2 is a plan view showing a state in which a current collector piece is attached to a negative electrode and a peripheral portion of the negative electrode is covered with an alkali-resistant heat-fusible resin.

FIG. 3 is a sectional view showing an embodiment of the sealed alkaline storage battery of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Thermal adhesive resin 4 Negative electrode 5 Thermal adhesive resin 7 Separator 8 Battery case 11 Annular gasket 12 Sealing lid

Claims (1)

[Claims] 1. A spirally wound electrode body in which a sheet-shaped positive electrode 1 and a sheet-shaped negative electrode 4 are spirally wound with a separator 7 interposed therebetween is housed in a battery case 8, and the opening of the battery case 8 is accommodated. In a sealed alkaline storage battery having a closed end, the peripheral edge of the positive electrode 1 and / or the peripheral edge of the negative electrode 4 is coated with the alkali-resistant heat-fusible resin 2, 5 including the cut end face thereof. A sealed alkaline storage battery.