JPS58158869A - Carbon positive pole for air cell - Google Patents

Abstract

PURPOSE:To maintain high electromotive force and charge current density and make it possible to control osmosis of electrolyte by controlling mainly the grain size of a raw material resin and active carbon. CONSTITUTION:In a nonburnt electrode, wherein a resin is mixed with active carbon while being heated and solidified, active carbon having the grain diameter of not more than 200 meshes and two kinds of resin having the grain diameters of not more than 100 meshes and not more than 300 meshes respectively are used as raw materials and said three kinds of raw materials are mixed to be followed by heating and deposition thus to form a state, wherein resins of two kinds, namely, large and small grain diameters are mixedly existing and deposited in an active carbon layer, thus to be molded. The critical range is difficult to be found for the compounding ratio of said three kinds of raw materials. It is, however, recommended that the range may preferably be active carbon 75-80wt%, the resin having the grain diameter of not more than 300 meshes 13-17wt% and the resin having the grain diameter of not more than 100 meshes 3-12wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anode having a novel composition for air batteries,
More specifically, in an unfired electrode in which resin is mixed with activated carbon and then heated and solidified, by controlling the particle size of the raw material resin and activated carbon, it is possible to maintain high electromotive force and discharge dust, and to increase the penetration of electrolyte. The present invention relates to the configuration of an anode that can control the

An air battery is a primary battery that uses oxygen in the air as a depolarizing agent, and has the following structure (air - 1 carbon, 1 electrolyte, 1 zinc e), but its carbon electrode does not absorb the electrolyte if it is not waterproof. The rate of penetration is fast and significantly shortens battery life, so in the case of fired electrodes, the electrode is immersed in a solution of waterproofing agent such as paraffin or resin, then the solvent is evaporated and a thin waterproof membrane is coated to control the penetration of the electrolyte. In the case of unfired electrodes, activated carbon and resin solution are kneaded, molded and then dried and solidified, or colloidal resin powder of 0.5μ or less and activated carbon are mixed and heated to form a waterproof membrane. It was a method that generated and solidified at the same time. In short, all of the above methods are based on the principle of coating the carbon surface with a thin waterproof film to control penetration of the electrolyte into the electrode.

On the other hand, the present invention differs from the known methods described above and the principle of the invention, in that the particle diameters of the resin particles and activated carbon are appropriately selected, mixed 17, and then heated and welded after mixing.
In addition to examining the blending ratio of these raw material components, we were able to obtain a strong electrode with a high electromotive force and a slow permeation rate of the electrolyte, which we have put to practical use.

That is, the present invention uses activated carbon with a particle size of 200 mesh or less and two types of resins with particle sizes of 100 mesh or less and 300 mesh or less as raw materials. After mixing these six types of raw materials, they are heated and welded, and as shown in the attached drawings. As will be explained, molding is performed by forming a state in which resins of two types of particle sizes are mixed and deposited in the activated carbon layer.

It is difficult to find a critical range for the blending ratio of these six types of raw materials, but preferably activated carbon is 75 to 80% by weight and particle size is 3.
00 mesh or less resin 13-17 weight ratio and particle size 10
A range of 3 to 12% by weight of resin with 0 mesh or less is recommended.

To illustrate an example of the implementation of the present invention, 75% by weight of activated carbon with a particle size of 200 mesh or less, 1% polyethylene with a particle size of 2 to 40μ
Mix 15% by weight of polyethylene with 5% by weight and 100-200 mesh particle size, put it into a molding machine, and make about 50% of polyethylene per 11% by weight.
5~ at 120~160°C while applying 1f' pressure.
After heating for 10 minutes, let it cool.

A battery was assembled using a known method in which one side of the 1.7 mm thick flat anode thus obtained was used as an air-facing surface and the other surface was used as a liquid-facing surface, zinc was used as the cathode, and caustic soda or caustic potash solution was used as the electrolyte. The battery was discharged at a constant current density until the voltage suddenly decreased, and the performance of the battery at that time was determined as follows.

Table 1 In contrast, the performance of the commercially available unfired battery was as follows: Table 2 From Tables 1 and 2 above, for the same current density, capacitance, and immersion area, the performance of the electrode according to the present invention was as follows: The thickness is 17 mm, but the commercially available product is 10 mm thick, clearly indicating that the electrolyte permeation rate of the product of the present invention is slow. Furthermore, the practical current density of conventional air batteries is said to be a maximum of approximately 5 mA/CΔ, but the present invention has the feature that it can be used even at 1[] mA/7, which also shows the superiority of the present invention. I can say that.

[Brief explanation of the drawing]

The drawing is an enlarged model diagram of a part of the structure of the electrode of the present invention. In the figure, the large black dots are resin particles with a particle size of 10D mesh or less, the small particles are resin grains with a particle size of 500 mesh or less, and the medium black dots are activated carbon particles with a particle size of 2[]0 mesh or less''.
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Claims (1)

[Scope of Claims] 1. An unfired electrode in which resin is mixed with activated carbon and solidified by heating, and there are two types of resin particle sizes: 300 mesh or less and 100 mesh or less, and activated carbon has a particle size of 200 mesh or less.
An anode for an air battery, characterized in that the anode is less than mesh. 2. Resin particle size of 16 to 1 500 mesh or less
Claim 1, characterized in that the blending ratio is 7% by weight, 6% to 12% by weight of particles having the same particle size of 100 mesh or less, and 75% to 80% by weight of activated carbon particles having a particle size of 200 mesh. Anode for air batteries.