JPH0529025A - Button type air cell - Google Patents

Abstract

PURPOSE:To improve reliability in discharge performance by forming recesses/ projections in a check pattern or in a radial pattern on the lower surface of a water repellent film without using an air diffusing paper brought into contact directly with an air hole arranged in the bottom part of a positive electrode case. CONSTITUTION:A water repellent film 3 is placed directly in a positive electrode case 1 having an air hole 1a on the bottom surface. Checkered projections are formed on the reverse surface 3a of the film 3, and these projection parts are brought into contact with the case 1, and recess parts are used as an air passage. An air electrode 4 consisting of activated carbon or manganese oxide and so on exists on the film 3, and a separator 5 is placed further thereupon, so that a positive electrode side constituting part can be formed. A zinc negative electrode 6 is housed separately in a negative electrode case 7 formed by adhering an insulating gasket 8 on the outer periphery, and is superposed upon the positive electrode side constituting part, and after the opening edge is caulked, a battery is sealed up. A rail paper 9 is stuck on the bottom surface of the case 1, and in the case when the battery is not used, an air hole 1a is sealed up. By arranging the film 3, reliability in continuous discharge performance is improved as the load becomes large, and productivity can be also improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a button type air battery having a water-repellent film excellent in air diffusion.

[0002]

2. Description of the Related Art In recent years, button type air batteries are becoming popular as a power source for hearing aids and the like in place of button type mercury batteries.

The structure of a conventional button type air battery will be described below with reference to the drawings. Figure 3 shows the structure of a conventional button-type air battery (height 3.6 mm, diameter 7.9 mm). As shown in FIG. 3, an air diffusion paper 22 is adhered to a positive electrode case 21 having air holes 21a on the bottom surface, a water-repellent film 23 having a smooth surface on both sides is placed thereon, and activated carbon or manganese oxide is placed thereon. After mounting the air electrode 24 composed of, for example, the separator 25 was further mounted thereon to form the positive electrode side component. Then, after fitting the components on the positive electrode side into a negative electrode case 27 (having an insulating gasket 28 adhered to the outer peripheral portion) accommodating a zinc negative electrode 26 composed of an alkaline electrolyte and zinc fluoride powder, the opening edge of the positive electrode case 21 is closed. They crimped to form a battery. Reference numeral 29 denotes a sticker paper, which closes the air hole 1a when the battery is not used, in order to prevent the deterioration of the battery performance during storage.

Of these constituent parts, the purpose of the water-repellent film 23 is to supply oxygen that has passed through the air diffusion paper 22 from the air holes 21a to the air electrode 24 and to pass from the zinc negative electrode 26 to the air electrode 24. This is to prevent the alkaline electrolyte from leaking out of the battery. Porous fluororesin is used as a material that satisfies this purpose.

Further, the purpose of the air diffusion paper 22 is to make the air holes 21.
This is for uniformly supplying the oxygen taken in from a through the water-repellent film 23 to the entire surface of the air electrode. For this reason, the air diffusion paper 22 (or the air diffusion film) needs to have much higher air permeability than the water repellent film 23. However, if the material is porous fluororesin, it is molded and processed into an extremely thin layer to achieve high air permeability. Must. However, in this molding and processing, since it becomes too soft and the tensile strength is lowered, it is difficult to put it into practical use in a battery production process in which it is continuously punched into a perfect circle. Further, even if it is punched out into a perfect circle, wrinkles are more likely to occur, so that it becomes difficult to adhere to the bottom surface of the positive electrode case 21 having the air holes 21a. A nonwoven fabric made of pulp, vinylon, or the like has been used as a material having high air permeability and not having the above-mentioned drawbacks.

However, the air diffusion paper 2 made of this non-woven fabric
Since 2 is rich in water supply, if the water repellent film 23, the air electrode 24, and the separator 25 are made to have the same diameter and placed below the water repellent film 23, the alkali diffusion from the outermost peripheral surface of the air diffusion paper 22 during storage of the battery can be prevented. The electrolytic solution permeates and leaks from the air holes 21a. This is because the alkaline electrolyte in the zinc negative electrode 26 easily advances downward from the outermost peripheral portion of the bottom surface of the insulating gasket 28. In order to prevent this liquid leakage, a stepped bottom surface is provided as the sticking surface of the seal paper 29 of FIG. 3, and the air diffusion paper 22 is adhered to this inner side surface. That is, the diameter of the air diffusion paper 22 is made smaller than the diameters of the other three layers of materials for accurate positioning.

The air diffusion paper 22 is adhered by dripping a small amount of water-based glue as an adhesive to a point on the inner surface of the stepped bottom surface that is farthest from the air holes 21a and surely contacts the air diffusion paper 22. After that, the air diffusion paper 22 was placed on this.

[0008]

However, in such a conventional structure, when the air diffusion paper 22 is adhered to the stepped bottom surface, it is an adhesive agent during storage due to the water supply of the non-woven fabric. There has been a problem that a small amount of water-based glue leaches out to the air holes 21a, the air holes 21a are partially blocked, and abnormal discharge occurs. Further, if the air diffusion paper 22 is simply placed without using an adhesive, the non-woven fabric will be extremely thin and thin, which may cause displacement and dropout in the battery mass production process. Therefore, the use of the adhesive was indispensable.

Furthermore, it is desirable not to use an air diffusion paper if possible. However, if the air diffusion paper is not used, the oxygen supply to the air electrode 24 will be insufficient only with the water-repellent film 23, and a battery having a short duration will be generated when a heavy load continuous discharge is performed. Can not be omitted.

The present invention solves such problems, and an object of the present invention is to provide a button type air battery which eliminates fluctuations in discharge performance and improves mass productivity.

[0011]

In order to solve this problem, the present invention provides a positive electrode case having an air hole on the bottom surface, a water repellent film, an air electrode and a separator placed in the positive electrode case, A zinc negative electrode containing zinc hydride powder and an alkaline electrolyte as a main component, and the positive electrode case is sealed to the negative electrode case via a gasket. The surface of the water repellent film in contact with the air holes is a cross board. The grooves are formed in the shape of eyes or radials.

[0012]

According to this structure, the oxygen diffused from the air holes can be spread over the entire surface of the air electrode without using the air diffusion paper, as in the case where the lower surface of the water-repellent film having the groove is formed using the air diffusion paper. A gas passage for diffusing and supplying the gas can be formed to rapidly activate the inside of the battery.

[0013]

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

FIG. 1 shows the structure of a button type air battery according to an embodiment of the present invention. The water-repellent film 3 is directly placed on the positive electrode case 1 having the air holes 1a on the bottom surface. As shown in FIG.
The particle-shaped unevenness shown in (A) is formed. The convex portion 10 contacts the positive electrode case, and the convex portion 11 serves as an air passage. An air electrode 4 made of activated carbon, manganese oxide, or the like is provided on the water-repellent film 3, and a separator 5 is placed on the air electrode 4 to form a component on the positive electrode side. Separately, a zinc negative electrode 6 made of zinc fluoride powder and an alkaline electrolyte is housed in a negative electrode case 7 having an insulating gasket 8 adhered to the outer periphery, positive electrode side components are stacked and inserted into the positive electrode case 1,
The battery is sealed by caulking the opening edge of the positive electrode case 1. Rail paper 9 is attached to the bottom surface of the positive electrode case 1 to seal the air hole 1a when the battery is not used. The difference from the conventional air battery is that the air diffusion paper is not used and that the grid-like projections shown in FIG. 2A are formed on the lower surface 3a of the water-repellent film 3. This water-repellent film was formed by embossing by pressing the uneven surface provided on the outer periphery of a resin or metal drum, on which the desired protrusions are formed, onto the sheet of the water-repellent film 3.

Each of the battery of this example and the conventional battery was stored at 20 ° C. for 1 month, and then the duration of heavy load continuous discharge and the defective rate of heavy load standard load and light load continuous discharge were measured (Table It is shown in 1). The duration (h) of (Table 1) is 20
The time required for the discharge voltage to drop to 0.9 v from the start of discharge in heavy load continuous discharge with a load resistance of 300Ω. The number of tests is 20 each. The failure rate (%) is the rate of occurrence of abnormal discharge due to air hole blockage during continuous discharge of heavy load and standard load using load resistances of 300Ω, 3kΩ, and 15kΩ at 20 ℃. It is 100 each.

[0016]

[Table 1]

As shown in (Table 1), in the battery of this example, the reliability of continuous discharge performance was improved as the load was increased.
And productivity is also improved.

The shape of the water repellent film 3 is shown in FIG.
It was molded as shown in (C). 2 (B) and 2 (C) are both water-repellent films in which radial grooves are formed by the same method as in FIG. 2 (A). As a result of performing the above-mentioned tests on these water-repellent films 3, the battery showed the same duration as the battery of this example (Table 1) and the defective rate was also 0%.

Also in FIGS. 2A and 2B, the reliability of continuous discharge performance is improved and the productivity is improved as the load is increased.

In this embodiment, the case where the groove shape on the lower surface of the water-repellent film 3 is formed in a grid pattern or a radial shape has been described, but it is easy to diffuse and supply the air entering from the air holes to the entire surface of the air electrode. It is needless to say that various shapes can be applied in consideration of the groove shape, pitch, irregularity, etc. as long as the gas passage can be formed.

[0021]

As is apparent from the above description of the embodiments, according to the present invention, a go board is formed on the lower surface of the water repellent film without using an air diffusion paper which is in direct contact with the air holes provided at the bottom of the positive electrode case. By forming the concavo-convex pattern in the shape of eyes or radii, it is possible to realize a button type air battery with improved reliability of discharge performance and mass productivity of batteries.

Further, it is possible to reduce man-hours and costs by omitting the air diffusion paper and its bonding step. In addition, since the step of aligning and arranging the air diffusion paper on the stepped bottom surface, which is the sticking surface of the sticker paper, is eliminated, the outer space of the stepped bottom surface can be used as an increase in the internal volume, and The capacity can be increased.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional view of a button type air battery according to an embodiment of the present invention.

FIG. 2A is a plan view of a groove shape of the same water-repellent film, FIG. 2B is a plan view of a groove shape of another water-repellent film, and FIG. Plan view of groove shape of water film

FIG. 3 is a partially cutaway sectional view of a conventional button type air battery.

[Explanation of symbols]

 1 Positive electrode case 3 Water-repellent film 3a Shape of water-repellent film contact surface with air holes 4 Air electrode 5 Separator 6 Negative electrode 7 Negative electrode case

Claims (1)

Claim: What is claimed is: 1. A positive electrode case having an air hole on the bottom surface, a water-repellent film, an air electrode and a separator are placed in the positive electrode case, and zinc hydride powder and alkaline electrolysis are placed in the negative electrode case. A structure in which a zinc negative electrode mainly composed of a liquid is filled, and the positive electrode case is sealed in the negative electrode case via a gasket, and a grid-shaped or radial groove is formed on the surface of the water-repellent film in contact with the air holes. Button type air battery.