JPS6276266A - Button type air-cell - Google Patents

Abstract

PURPOSE:To prevent electrolyte from permeating through a water-repellent layer to an air-diffusion paper by forming a recess in a positive electrode case such that the difference of inner diameter between the upper and lower sections will take a predetermined value. CONSTITUTION:A recess 23 is formed in a positive electrode case 21 such that the dimensional difference of inner diameter between the upper and lower sections will be 0-1.0mm. consequently, the sideface of the recess 23 in the positive electrode case 21 will be vertical or approximately vertical, and when containing an air-diffusion paper 24 in said recess 23, a slight gap will occur or no gas will occur between the recess and the air-diffusion paper. Consequently, permeation of electrolyte through a water-repellent layer due to crack occurred in the water-repellent layer can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a button-type air battery, and more particularly, to a button-type air battery in which the shape of the air diffusion paper storage recess of the special positive electrode case is improved.

[Technical background of the invention and its problems]

As a conventional button-type air battery, one having the structure shown in FIG. 3 is known. That is, 1 in the figure is a positive electrode case having an air supply hole 2 and an air diffusion paper storage recess 3 at the bottom. An air diffusion paper 4 is housed in the recess 3 of the positive electrode case 10, and a fluororesin water-repellent layer 5, a positive electrode catalyst layer 6, and a separator 2 are sequentially stacked and stored on the diffusion paper 4 to form a positive electrode side assembly. are doing. On the other hand, the negative electrode side assembly has a structure in which a cap 9 which also serves as a negative electrode terminal is mounted on a gasket 8, and a negative electrode active material 10 is filled in the cap 9. Then, by fitting the positive electrode assembly and the negative electrode assembly and bending the opening side of the positive electrode case 1 inward, the battery elements in the positive electrode case 1 and the cap 9 are sealed.

By the way, the purpose of the air diffusion paper 4 is to uniformly diffuse the air entering through the air supply hole 2 of the positive electrode case 1 to the positive electrode catalyst layer 6, and to prevent deformation of the fluororesin water-repellent layer 5 and the positive electrode catalyst layer 6. It is established for the purpose of preventing. Also,
The positive electrode case 10 recess 3 has a gentle inclination angle and a tab p.
The upper inner diameter is larger than the lower inner diameter, and the diffusion paper 4 to be accommodated in the recess 3 is sufficiently smaller than the recess 3.

However, when the water repellent layer 5 is pushed toward the air diffusion paper 4 due to expansion due to discharge of the negative electrode active material 10, there is a gap between the air diffusion paper 4 and the recess 3 of the positive shuttle case 1, so that the water repellent layer 5 When ring-shaped depressions 11 are formed and cracks occur, the air diffusion paper 4 becomes wet. The air diffusion paper 4 wetted with the electrolyte prevents the air entering from the air supply hole 2 formed at the bottom of the positive electrode case 1 from diffusing into the positive electrode catalyst layer 6, thereby reducing the activity of the positive electrode catalyst layer 6. . As a result, there was a problem in that the battery performance deteriorated significantly, and if the battery was left with a load connected to it after discharge, liquid leaked from the air supply hole 2.

For this reason, it is conceivable to reduce the amounts of the negative electrode active material and electrolyte to prevent leakage, but this poses a problem of decreasing battery capacity.

[Purpose of the invention]

The present invention aims to provide a button-type air cell in which a water-repellent layer is undone due to expansion of a negative electrode active material due to discharge, and the electrolyte is prevented from passing through the water-repellent layer and reaching the air diffusion paper. It is.

[Summary of the invention]

The present invention provides air diffusion paper,
In an air cell in which a water-repellent layer and a positive electrode catalyst layer are sequentially laminated, the recess formed in the positive electrode case is shaped such that the difference between the inner diameter of the lower part and the inner diameter of the upper part is 0 to 1, OU. It is something to do.

According to the above-described configuration, the side surfaces of the recess of the positive electrode case are vertical or nearly vertical, and when the air diffusion paper is stored in the recess, a slight gap or no gap is created between the recess and the air diffusion paper. . As a result, even if the negative electrode active material expands due to discharge and the water repellent layer is pushed toward the air diffusion paper, there is little or no gap between the air diffusion paper and the recess, so the water repellent layer It is possible to prevent ring-shaped depressions from occurring. As a result, it prevents the electrolyte from passing through the water-repellent layer due to the occurrence of cracks in the water-repellent layer, prevents the active ability of the positive electrode catalyst layer from deteriorating for a long period of time, and allows for a long period of time when a load is connected to the page after discharge. Even if left in this state, leakage from the air supply hole can be prevented.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

Reference numeral 21 in the figure is a positive electrode case having an air supply hole 22 and four parts 23 for storing air diffusion paper at the bottom.

An air diffusion paper 24 is housed in the recess 23 of the case 21, and on the diffusion paper 24 is a fluororesin water-repellent layer 25, and a positive electrode filled with a catalytic material made of a nickel net mixed with activated carbon and polytetrafluoroethylene powder. The catalyst M26 and the separator 22 are sequentially stacked to form a positive electrode assembly. On the other hand, the negative electrode side assembly has a structure in which a cap 29 which also serves as a negative electrode terminal is mounted on a gasket 28, and a negative electrode active material 30 impregnated with an electrolytic solution is filled in the cap 29. Then, by fitting the positive electrode assembly and the negative electrode assembly and bending the opening side of the positive electrode case 21 inward, F)ff
The battery elements in the positive electrode case 1 and the cap 29 were sealed to produce a PR44 size air battery.

Therefore, as shown in FIG. 2, the recess 2 of the positive electrode case 21
The lower inner diameter dimension a2 in 3 is 81, and the lower inner diameter dimension a, O difference a, -am with respect to the upper inner diameter dimension a is Q, Q, 5U, 1. Qill.

1.511j, 2. OvA batteries were prepared, and these batteries were subjected to 2500 continuous discharges. The results are shown in the table below, which shows the discharge duration as an average of 6 batteries and the leakage rate as an average of 10 batteries.

Note that the air diffusion paper used had the same size as the lower inner diameter dimension am of the recess.

As is clear from the above table, the recessed portion has the above-mentioned size difference a, -a
It can be seen that by using a positive electrode case in which , iai or less, an air battery with a long discharge duration and a low leakage rate can be obtained.

On the other hand, when using a positive electrode case with a concave portion with a size difference of more than one fin, the water-repellent layer deforms during sealing9, is prone to cracking, reduces discharge performance, and prevents air supply holes from forming. Leakage occurs.

〔Effect of the invention〕

As described in detail above, according to the present invention, the water-repellent layer is dented due to expansion of the negative electrode active material due to discharge, it is possible to prevent cracks from occurring in the water-repellent layer, and to prevent the electrolyte from passing through the water-repellent layer. It is possible to provide a high-performance, highly reliable button-type air battery that can stably maintain the active ability of the layer for a long period of time and prevent liquid leakage due to discharge.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a button-type air battery showing an embodiment of the present invention, FIG. 2 is a partially enlarged sectional view of the positive electrode case of FIG. 1,
FIG. 3 is a sectional view showing a conventional button-type air battery. 2... Positive electrode case, 22... Air supply hole, 23...
... recess, 24 ... air diffusion paper, 25 ... water repellent layer, 26 ... positive electrode catalyst layer, 29 ... cap, 30 ...
...Negative electrode active material.

Claims (1)

[Claims] An air battery in which an air diffusion paper, a water repellent layer, and a positive electrode catalyst layer are sequentially laminated in a positive electrode case having an air supply hole at the bottom and a recess for storing air diffusion paper, the recess formed in the positive electrode case. A button-type air cell characterized in that the difference between the inner diameter of the upper part and the inner diameter of the lower part is 0 to 1.0 mm.