JPH05205769A - Sealed metal oxide hydrogen storage battery - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a sealed metal oxide / hydrogen storage battery that does not cause an internal short circuit and does not cause a defect when a spiral electrode body is manufactured. [Structure] Adhesive tapes 7a and 7b capable of being heat-welded are adhered to the innermost peripheral end portion 2a and the outermost peripheral end portion 2b of the sheet-shaped negative electrode 2, and the separator 3 is heat-sealed to the adhesive tapes 7a and 7b. Fix it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed metal oxide / hydrogen storage battery, and more particularly to improvement of a spiral electrode body portion thereof.

[0002]

2. Description of the Related Art In a sealed metal oxide / hydrogen 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. Since the spirally wound electrode body is housed in a cylindrical battery case with a bottom, the cut end of the wire mesh used as a support for the negative electrode penetrates the separator and contacts the positive electrode, causing an internal short circuit. There is a problem that is likely to occur.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the problem of the internal sealed metal oxide / hydrogen storage battery, which is liable to cause an internal short circuit, and has the reliability of preventing internal short circuit. An object is to provide a highly sealed metal oxide / hydrogen storage battery.

[0004]

According to the present invention, a heat-sealable pressure-sensitive adhesive sheet is attached to the innermost peripheral edge and the outermost peripheral edge of a sheet-shaped negative electrode to prevent the occurrence of internal short circuits. In addition to achieving the object, the separator is heat-fused and fixed to the adhesive tape to prevent the occurrence of defects during the manufacture of the spiral electrode body.

That is, by sticking heat-sealable adhesive sheets to the innermost peripheral edge and the outermost peripheral edge of the sheet-shaped negative electrode, the cut end face of a wire mesh or the like used as a support for the negative electrode is covered. Then, the cut end of the support was prevented from penetrating the separator and coming into contact with the positive electrode.

Then, by fixing the separator to the adhesive tape by heat fusion, it is possible to prevent the generation of wrinkles and winding disorder when wound in a spiral shape, and the occurrence of defects in manufacturing the spiral electrode body. It also prevented this.

In the present invention, as the adhesive tape, for example, a masking tape (trade name: Scotch No.
219) and the like can be used.

As the separator, for example, polyamide non-woven fabric, synthetic resin non-woven fabric such as sulfonated polypropylene or grafted polypropylene is used.

[0009]

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

Example 1 FIG. 1 is a fragmentary side view of a sealed type metal oxide / hydrogen storage battery of Example 1, and FIG. 2 is a cross section of a stack of a negative electrode and a separator before being spirally wound. It is a figure and FIG. 3 is the top view.

First, the production of the negative electrode and the spiral electrode body will be described.

The composition is (Ti _0.5 Zr _1.5 V _1.0 N _3.0 )
_{Using 0.8} Cr _0.2 hydrogen storage alloy as the negative electrode active material,
Using a stainless steel net as a support, the above hydrogen storage alloy is rolled together with the stainless steel net and sintered at about 1000 ° C. for 30 minutes to produce a sheet-shaped sintered body, which is cut into a predetermined size. As a result, a sheet-shaped negative electrode was produced.

As shown in FIGS. 2 and 3, adhesive tapes 7a and 7b are attached to the cut ends of the sheet-shaped negative electrode 2, that is, the innermost peripheral end 2a and the outermost peripheral end 2b when wound. It was attached so that the end face was completely covered. As the adhesive tapes 7a and 7b, the above-mentioned Scotch No. 219 (trade name) was used.

Next, the separator 3 made of polyamide nonwoven fabric was heat-fused and fixed to the adhesive tapes 7a and 7b.

Since FIG. 2 schematically shows,
Although it is illustrated that there is a gap between the negative electrode 2 and the separator 3 in a portion where the adhesive tapes 7a and 7b are not interposed, the adhesive tapes 7a and 7b and the separator 3 are thin, There is no gap between the negative electrode 2 and the separator 3 except for a part.

Then, a sheet-shaped positive electrode containing nickel hydroxide as an active material was placed on the separator 3 which is a stack of the separator 3 and the negative electrode 2 and was spirally wound to produce a spirally wound electrode body.

The spiral electrode body is housed in a battery case,
An electrolytic solution made of an alkaline aqueous solution was injected, and thereafter, a sealed metal oxide / hydrogen storage battery having a structure shown in FIG. 1 was manufactured according to a conventional method.

The sealed metal oxide / hydrogen storage battery shown in FIG. 1 will be described. Reference numeral 1 is a positive electrode, and this positive electrode 1 is a sheet-like material having nickel hydroxide as an active material. The sheet-shaped negative electrode 2 is superposed with the sheet interposed and wound in a spiral shape.

Reference numeral 4 denotes a metal battery case. The battery case 4 accommodates the spiral electrode body, and an electrolytic solution (35
(% By weight potassium hydroxide aqueous solution), and after connecting the lead body 8 and arranging the insulating material 9, the sealing lid 6 is arranged in the opening of the battery case 4 via the annular gasket 5.
The opening edge portion 4a of the battery case 4 is caulked and sealed to complete the state shown in FIG.

However, the sealing lid 6 is activated when a large amount of gas is generated inside the battery and the internal pressure rises abnormally, and the gas inside the battery is released to the outside of the battery to prevent the battery from bursting. Vent mechanism is incorporated.

That is, when the internal pressure of the battery rises abnormally, the elastic valve body 10 is deformed to form a gap between the valve hole 11 and the exhaust hole 12, and the gas inside the battery is pumped through the valve hole 1
A vent mechanism for releasing the gas to the outside of the battery through the exhaust port 1 and the exhaust hole 12 is incorporated in the sealing lid 6.

Comparative Example 1 A spiral electrode body and a spiral electrode body were prepared in the same manner as in Example 1 except that the adhesive tape was not attached to the innermost peripheral edge portion or the outermost peripheral edge portion of the negative electrode and the separator was not heat-sealed. A sealed metal oxide / hydrogen storage battery was manufactured.

Table 1 shows the results of examining 100 occurrences of each of the batteries of Example 1 and Comparative Example 1 and examining the occurrence of internal short circuit. The presence or absence of the internal short circuit was judged by measuring the open circuit voltage, and the result was displayed in the mode in which the denominator indicates the total number of batteries prepared and the numerator indicates the number of batteries in which the internal short circuit occurred.

[0024]

[Table 1]

In addition, in the above-mentioned Example 1 and Comparative Example 1, the results of examining the occurrence of defects during the work of the spiral electrode body are shown in Table 2.
Shown in.

That is, in Example 1 and Comparative Example 1, 100 spiral electrode bodies were produced by a normal working procedure, and the occurrence of wrinkles and winding disturbances during winding was examined, and the number of defects was determined. Is shown in Table 2. In addition, also in Table 2, the results are shown in such a manner that the total number of the spirally wound electrode bodies produced is shown in the denominator and the number of defects generated is shown in the numerator.

[0027]

[Table 2]

As is clear from the results shown in Tables 1 and 2,
According to the present invention, the occurrence of an internal short circuit is prevented, and the occurrence of a defect at the time of manufacturing the spiral electrode body is prevented.

[0029]

As described above, in the present invention, heat-adhesive pressure-sensitive adhesive tapes are attached to the innermost peripheral edge and the outermost peripheral edge of the sheet-shaped negative electrode, and the separators are heat-fused to these pressure-sensitive adhesive tapes. It was possible to prevent the occurrence of an internal short circuit in the sealed metal oxide / hydrogen storage battery and to prevent the occurrence of a defect during the production of the spiral electrode body.

[Brief description of drawings]

FIG. 1 is a fragmentary side view showing an embodiment of a sealed metal oxide / hydrogen storage battery of the present invention.

FIG. 2 is a sectional view of a stack of a negative electrode and a separator before being spirally wound.

FIG. 3 is a plan view of a stack of a negative electrode and a separator before spirally winding.

[Explanation of symbols]

 1 Positive Electrode 2 Negative Electrode 2a Innermost End 2b Outermost End 3 Separator 4 Battery Case 5 Annular Gasket 6 Sealing Lid 7a Adhesive Tape 7b Adhesive Tape

Claims (1)

[Claims] 1. A sheet-shaped positive electrode 1 having a metal oxide as an active material and a sheet-shaped negative electrode 2 having a hydrogen storage alloy as an active material are spirally wound with a separator 3 interposed therebetween. The spirally wound electrode body produced was used to form a cylindrical battery case 4 with a bottom.
In a sealed metal oxide / hydrogen storage battery which is housed in a battery case 4 and has the opening of the battery case 4 sealed, the sheet-shaped negative electrode 2 can be heat-welded to the innermost peripheral end 2a and the outermost peripheral end 2b. Adhesive tape 7a, 7b is attached,
A sealed metal oxide / hydrogen storage battery characterized in that a separator 3 is heat-welded and fixed to 7b.