JPS5931002Y2 - flat alkaline battery - Google Patents

Description

[Detailed Description of the Invention] The object of the present invention is to improve the leakage resistance of a flat alkaline battery and to reduce the internal resistance of the battery.

A conventional flat alkaline battery of this type has an insulating gasket with a cross-section shaped like a letter C, which comes into contact with the inner bottom surface of a metal case a and has a step C that projects inward, as shown in Figure 3 of the drawing.
d is fitted into a metal case, and a gelled negative electrode mixture g is placed inside the separator f, which has cellophane or a microporous synthetic resin film laminated to cellophane on the upper surface of the step C and the positive electrode mixture e. There is also a structure in which a metal sealing plate filled with metal is placed and the opening of the metal case a is bent inward to seal it, but this structure works well because the separator is pressed only with the metal sealing plate. This resulted in an accident in which the alkaline electrolyte in the negative electrode leaked to the outside through the gap between the separator and the metal sealing plate.

In addition, when the battery is turned on, the stepped portion C is compressively deformed, extends in the inner diameter direction, and shrinks, lifting the positive electrode mixture e toward the gelled negative electrode mixture g, causing poor electrical contact between the positive electrode mixture and the metal case inside the battery. It had the disadvantage of increasing resistance.

The present invention solves the above-mentioned conventional drawbacks, and one embodiment thereof will be described below.

In FIGS. 1 and 2, 1 is made of a metal plate whose outer surface is coated with nickel, and has an outer dimension of 11.6 mm and a height dimension of 1.
It is a 6 mm metal case, and inside the case 1 is an insulating gasket 4 made of synthetic resin such as nylon or polyethylene that abuts from the inner wall 2 of the case to the inner bottom 3 of the case.
are fitted.

The insulating gasket 4 has a cross-sectional shape in which a cylindrical part 5 in contact with the inner wall 2 of the metal case 1 and an annular step part 6 protruding inwardly below the cylindrical part 5 are integrally formed. ing.

7 is a positive electrode mixture made of silver oxide and scaly graphite, and a cylindrical metal current collector 8 is fitted to the outer peripheral edge of this positive electrode mixture 7.

The inner peripheral edge of the annular step 6 is in contact with the outer peripheral edge of the cylindrical metal current collector 8 surrounding the positive electrode mixture, and the upper surface 9 of the annular step 6 covers the upper surface of the positive electrode mixture 7. A peripheral portion 11 of a separator 10, which is made of cellophane or cellophane laminated with a microporous polyethylene film, is placed.

Further, an insulating ring 12 made of synthetic resin such as Teflon or nylon is located on the upper surface of the peripheral portion 11 of the separator.

This insulating ring 12 is wider than the upper surface 9 of the annular step 6 of the insulating gasket, and the inner peripheral edge 13 of the ring 12 covers the outer peripheral edge of the positive electrode mixture 7.

14 is an electrolyte holding layer made of a nonwoven fabric of rayon fibers.

Reference numeral 15 denotes a metal sealing plate filled with a gelled negative electrode mixture 16 which is a mixture of an alkaline electrolyte made of caustic soda, a gelling agent such as sodium polyacrylate, carboxymethylcellulose, and zinc powder; The peripheral edge 17 of is placed on the outer peripheral edge of the insulating ring, and the opening 18 of the metal case 1 is bent inward, so that the cylindrical part of the insulating gasket 4 is interposed between the metal case and the metal sealing plate. The batteries are sealed.

The battery A of the present invention shown in FIG. 1 explained in the above embodiment and the battery B explained in the conventional example shown in FIG.
After assembling 30 of each type 1116S batteries and storing them in an atmosphere at a temperature of 45°C and a humidity of 90% for 40 days, an external inspection was performed using a 20x magnifying glass to determine the number of leaks, and the temperature after manufacture was determined. After storage at 20° C. for 30 days, the internal resistance was measured at IKHz using an impedance meter and the results were as follows.

In the flat alkaline battery according to the present invention, an insulating ring 12 having a width that covers the upper surface of the annular step of the insulating gasket and the upper peripheral edge of the positive electrode mixture is interposed between a metal sealing plate 15 and a separator 10. Therefore, the peripheral edge of the metal sealing plate is held between the cylindrical portion 5 of the insulating gasket 4 and the insulating ring 12, so that leakage of the alkaline electrolyte can be prevented.

Furthermore, even if the insulating gasket 4 is compressed and deformed during battery operation, the inner peripheral edge 13 of the insulating ring 12 can prevent the annular stepped portion of the gasket from escaping toward the gelled negative electrode mixture. It deforms and moves in the direction of opening No. 1.

As a result, the annular stepped portion of the insulating gasket is less narrowed in the radial direction, and the gasket, which comes into contact with the side edge of the positive electrode mixture through the cylindrical current collector, lifts the positive electrode mixture toward the gelled negative electrode mixture. This has great industrial value, such as reducing battery internal resistance without inhibiting electrical contact between the positive electrode mixture and the metal case.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a flat alkaline battery according to an embodiment of the present invention. FIG. 2 is a sectional view of the battery of the present invention shown in FIG. 1 before being sealed. The second figure is a sectional view of a conventional flat alkaline battery. DESCRIPTION OF SYMBOLS 1... Metal case, 4... Insulating gasket, 6... Annular step part, 7... Positive electrode mixture.

Claims (1)

[Scope of utility model registration request] In a flat alkaline battery in which an insulating gasket is interposed between a metal case and a metal sealing plate in which a battery power generation element of a positive electrode mixture, a gelled negative electrode mixture, and a separator interposed between the two electrodes is housed, The insulating gasket has a cylindrical body having an angular cross-sectional shape and abuts from the inner wall to the inner bottom of the metal case, and an annular step portion protruding inwardly below the cylindrical portion, and an inner peripheral edge of the annular step. is in contact with the cylindrical current collector surrounding the positive electrode mixture, and the upper surface of the annular step and the upper surface of the separator, which is laid on the upper surface of the annular step of the insulating gasket and the positive electrode mixture, 1. A flat alkaline battery characterized in that an insulating ring covering an upper peripheral portion is provided between a separator and a metal sealing plate, and an opening of a metal case is bent inward and sealed.