JPS60136165A - Air electrode - Google Patents

Abstract

PURPOSE:To increase mechanical strength and improve leakage resistance of cylindrical joining portion by mending defective parts of water repellent layer and porous catalyst-layer in a joining portion with plyolefin family copolymer. CONSTITUTION:An air electrode is produced, for example, from a three layer structure sheet prepared by stacking a water repellent layer, a porous catalyst- layer, and a current collector in order and pressing them. The sheet is curved or bent so that the water repellent layer exists outside and part of both ends of the sheet is lapped to form a cylinder. Polyolefin family copolymer is impregnated in the lapped portion, and the lapped portion is bonded in liquidtightness with polyolefin family copolymer by using an ultrasonic welder. Mechanical strength is increased by welding of current collecting layer, and leakage resistance in the lapped portion is improved by filling chemical resistant polymer resin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cylindrical air electrode, and more particularly to a cylindrical air electrode with high mechanical strength at the joint and excellent leakage resistance. .

[Technical background of the invention and its problems]

I, R-6, LR-14, and other types of cylindrical air drum electrodes have a water-repellent layer with oxygen gas permeability, a porous catalyst layer with oxygen gas reduction ability, and a polished current collector. The sheet-like three-layer structure laminated and pressed in this order is bent to form a cylinder with the water-repellent layer on the outside, and the image side end of the cylinder is glued with synthetic rubber or epoxy resin adhesive. It is configured as a liquid-tight cylindrical electrode in contact with the electrode.

Here, the water-repellent layer is generally made of polytetrafluorocarbon.
x From materials such as fluorine, polypropylene such as tyrene, polytetrafluoroethylene-hexafluoropropylene copolymer, polyethylene-tetrafluoroethylene copolymer, etc., for example, powder with a particle size of 0.2 to 0.4μ. Porous sheets that have oxygen gas permeability are used, such as sintered bodies, paper-like sheets made from heat-treated fibers, woven cloth sheets, and film-like sheets.

In addition, the porous catalyst layer is made of activated carbon powder supported with catalysts such as tungsten carbide, nickel, silver, platinum, and palladium coated with nickel tungstic acid, palladium, and cobalt, which have low oxygen reduction overpotentials, and polytetrafluorocarbon powder. It is formed by integrating a metal-bonded porous body, a carbon porous body, a carbon fiber nonwoven fabric, etc. using ethylene or the like as a binder.

Recently, in order to improve workability in this bonding process, adhesives made of hot melt adhesives such as polyethylene, polyethylene-vinyl acetate copolymer, polyamide, and polyisobutylene have been developed. Attempts have also been made to heat the parts to approximately 250°C and press them together.

However, in either method, the adhesive or hot-melt adhesive sheet must be in liquid-tight contact with the above-mentioned water-repellent layer. Therefore, its adhesive effect is extremely low.

Therefore, the mechanical strength of the bonded portion decreases, and furthermore, when the inside of the electrode is filled with a powdered zinc cathode mixture dispersed in a gelatinous solution, the decomposition solution leaks from the bonded portion. This situation often occurs.

[Purpose of the invention]

The present invention solves the above-mentioned drawbacks and basically consists of a water-repellent layer,
A cylindrical or square body formed from an electrode sheet consisting of three layers, a porous catalyst layer and a current collector layer, has high mechanical strength at the joint part, and is also completely liquid-tightly joined and has excellent leakage resistance. The purpose is to provide a cylindrical air electrode.

[Summary of the invention]

The air electrode of the present invention consists of a water-repellent layer with oxygen gas permeability, a porous catalyst layer with oxygen gas reduction ability, and an assembly layer, and a sheet with a three-layer structure in which these layers are laminated and pressed together. , curved or folded into a predetermined shape with the water-repellent layer on the outside;
A cylindrical or rectangular cylindrical body having a structure in which both ends of the sheet are partially overlapped by bending and the overlapping portions are joined, and the overlapping portion is impregnated with a polyolefin multi-component copolymer, and the overlapping portion is are bonded together using the polyolefin copolymer or by welding the layers of the current collector in the overlapping portion, and the missing portions of the water repellent layer and the porous catalyst layer at the joint are covered with the polyolefin copolymer. It is characterized by being repaired with a copolymer.

That is, the air electrode of the present invention is manufactured, for example, from a sheet of a three-layer structure in which a water-repellent layer, a porous catalyst layer, and an assembly layer are laminated in this order and pressed together. As the water-repellent layer, an oxygen gas permeable sheet made of polytetrafluoroethylene, polytetrafluoroethylene-hexafluoropropylene copolymer, polyethylene-tetrafluoroethylene copolymer, polypropylene, etc. is used, and a porous sheet is used. As a catalyst layer, platinum; palladium; silver; manganese dioxide; activated carbon; nickel tungstic acid.

Tungsten carbide coated with palladium F-balt,
A conductive porous sheet is used, which is made by binding activated carbon powder carrying nickel, silver, platinum, palladium, etc. with polytetrafluoroethylene. Examples of the current collector layer include a nickel wire mesh, an expanded metal thin plate, and a punched metal thin plate.

Curve (cylindrical electrode) or bend (prismatic cylindrical electrode) this three-layer structure so that the sheetra water-repellent layer is on the outside.
Then, parts of both side ends of the sheet are overlapped to form a cylinder. Next, this superimposed part is impregnated with a polyolefin multi-component copolymer, and the superimposed part is made liquid-tight with the polyolefin multi-component copolymer using an ultrasonic welder, an island frequency heating machine, a heat sealer, etc. It is glued together.

In order to connect the overlapping portions of the twisted air electrodes in a liquid-tight manner and with increased mechanical strength, the overlapping portions must be connected directly.
Alternatively, remove the water repellent layer and porous catalyst layer in this overlapping area, and remove the exposed aggregate layer.
Welding is performed by welding methods such as tM welding, beam welding, and laser bath welding. In addition, 'A' where the current collector layer is exposed from the beginning
If it is, weld it as is.

Unfortunately, at this time, the inside and outside of the cylinder are connected to each other in the second part, and are not in a liquid-tight state.

The riL'ux of the present invention is a product in which the defect is repaired in a liquid-tight manner by providing a polyolefin multi-component copolymer layer on the defect Ld1, which is not in a liquid-tight state.

The polyolefin-based multicomponent copolymer used in the present invention includes polyethylene, polyethylene terephthalate, polypropylene, vinyl! il(+1'
=, vinylidene chloride resin, fluorine resins such as polytetrafluoroethylene, acrylic resins, styrene resins, etc., and can be used for acrylonitrile-butadiene copolymers, acrylonitrile-butadiene-styrene copolymers, ethylene- Copolymers of the above resins such as vinyl acetate copolymers can be mentioned. The present invention provides them with an acetoxy group (-0COCH3), a hydroxyl group (-ol-
x), the inclusion of polar groups such as carboxyl groups (-Cool-1) in the molecular chain is a 4+ sign, and by incorporating these polar groups into the polymer chain, the The adhesion of the copolymer to various materials can be improved.

In particular, when the above polar group is introduced into the ethylene-[vinyl acid copolymer], the strength and elongation at break are large (elongation at break: 440-750 cracks, 1-11, elasticity: 07-1.21).
03rcg/all) This resin has both flexibility and rigidity and has excellent adhesive properties, and by using this resin, it is possible to connect the desired air electrode more firmly and liquid-tightly.

〔Effect of the invention〕

In the air electrode obtained according to the present invention, its mechanical strength is increased by welding the main body layers, and the leakage resistance of the overlapping portion is ensured by liquid-tightly filling with chemical-resistant polymer resin. Therefore, it is useful because its mechanical strength and leakage resistance are improved as a whole.

[Example of “Hayuu”]

Hereinafter, a description will be given of a kettle-6 type zinc-air battery according to the present invention as an example.

Examples 1 and 2 Micropores with an average pore diameter of 10μ were uniformly distributed as a water-repellent layer.
A porous PTFE film with a thickness of 100μ was loaded with activated carbon powder with an average particle size of 100μ on which 5% of the base was supported as a catalyst layer.
Fj! A film having a thickness of 05 nm and 1 m, which was prepared by rolling the mixed powder mixed with powder I and rolled by a conventional method, was prepared as a layer of a Nisokuru wire mesh having a diameter of 0.1 mm and a diameter of 40 mm.

These are made into 4λ layers under the above-mentioned normal pressure, and the total weight is 1 ton.
A polarized sheet was obtained by applying 1D pressure at a pressure of /clst.

A1: Form the electrode sheet into a cylindrical shape, apply electric current to the rlJ of the end portion 2, and then use the ethylene-
A partially cured product of vinyl acetate copolymer with the following chemical structural formula (
A type containing an acetoxy group or a hydroxyl group represented by 1) and a type containing an acetoxy group, a hydroxyl group or a carboxyl group represented by (2)0COOf1301-■ are bonded by heat and pressure to form a cylindrical shape. 2 was produced.

Examples 3 and 4 An f4m sheet was prepared in exactly the same manner as in Examples 1 and 2,
The above structural formula (1) is applied to the overlapped part of this electrode sheet,
The core electrode sheet was impregnated with the multicomponent copolymer shown in (2) and then formed into a cylinder, and a cylindrical electrode 3.4 was prepared in exactly the same manner as in Examples 1 and 2.

Examples 5 and 6 Electrode sheets were prepared in exactly the same manner as in Examples 3 and 4, and the heavily impregnated portions were impregnated with a multi-component copolymer, formed into a cylinder, and welded with a partial sound spot weld of overlapped nickel wire mesh. did.

When this cylindrical shape ``[d(4)'' is bath-welded with the sporato welder, the lζ-deficient portion and its surrounding area are expressed by the above structural formula (
The multi-component copolymers shown in 1) and (2) are installed in the form of a fused head, and the defective part and its surrounding area are placed in a tub 1;
j, Cylindrical electrodes 5 and 6 were created.

The electrode sheet prepared in exactly the same manner as in Examples J and 2) was formed into a circular shape, the ends of which were tied together as they were, and a sheet made of polyethylene was placed in that area. A composite sheet consisting of a sheet of melt adhesive R'f agent and a sheet of PTFN was placed so that the hot melt adhesive side was pressed against the sheet, and the entire sheet was heated to 200'01300kq/c:nf.
A cylindrical battery was produced by thermal compression bonding with a force of n. This was taken as a comparative example. Examples 1 to 6 are electrodes of the present invention, and comparative examples are conventional electrodes.

The tensile strength of the bonded portions of five of each of these seven types of cylindrical electrodes was measured. In addition, 50 LR-6 type cylindrical zinc-air battery cans were made from these four electrodes according to a conventional method, and all of these were stored at room temperature (25°C) for one month. We looked into cases of leakage.

The above results are shown in the table as average values for each battery.

From the results shown in the table above, it can be seen that by using the cylindrical pneumatic electrode a of the present invention, a cylindrical pneumatic electrode having high mechanical strength and excellent leakage resistance can be obtained.

Although the above embodiments have been described with respect to zinc-air batteries, it goes without saying that they can also be applied to battery systems that use other air electrodes, such as air-fluminiram, nitrogen-magnesium, etc.

Claims (1)

[Scope of Claims] (1) A three-layer structure consisting of a water-repellent layer having oxygen gas permeability, a porous catalyst layer having oxygen gas reduction ability, and a current collector layer, which are laminated. The electrode sheet of the body is a cylindrical or rectangular tube body having a structure in which the electrode sheet is bent or bent into a predetermined shape so that both ends of the sheet partially overlap, and the overlapping portion is joined, and the overlapping portion is made of a polyolefin multi-component material. An air electrode characterized by being bonded with a polymer. (2. An air electrode according to Claim 1, characterized in that the mold part of the electrode sheet is impregnated with a polyolefin multi-component copolymer. +3) 'h nrT: Claim 1 or Claim 1. In Section 2, the current collector layer at the overlapped part of the electrode sheets is welded and joined, and the defective part and surrounding part of the water repellent layer and the porous soot layer at the joint part are repaired with the polyolefin multi-component copolymer. An air electrode characterized by comprising: (4) In claims 1, 2, and 3, the polyolefin multicomponent copolymer is polyethylene or an ethylene-vinyl acetate copolymer containing at least one acetoxy group, hydroxyl group, or carfoyacyl group. An air electrode characterized in that it is a copolymerized mixture of two.