JPS58186173A - Air cell - Google Patents

Abstract

PURPOSE:To secure an air cell that will not go down in a discharge capacity even when it is stored for a long period of time, by using such a sealing material as one made up of more than two kinds of layers of a film comprising a constituent element being small in at least either transmissivity among steam, oxygen and carbon dioxide gas transmissivities. CONSTITUTION:An air hole 10 is hermetically sealed by a sealing material 11 that implies a composite film which is formed by laminating more than two kinds of film capable of satisfying at least either one of the following conditions and is also able to meet any of the following conditions, while those conditions are, steam transmissivity below 900, oxygen transmissivity below 5, and carbon dioxide gas transmissivity below 20, (each unit of above numerical values is X10<11>cc.cm<2>.Hg in either case). In this connection, as a resin material being small in steam transmissivity there are polyvinyl fluoride, nylon 11, polytriethylenechloride fluoride and vinyl chloride-vinylidene chloride copolymer, while as a resin material being small in oxygen and carbon dioxide gas transmissivity, those of polyvinyl fluoride, polyvinylidene fluoride, nylon 6, nylon 11, damp-proof cellophane, etc., can be enumerated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an air battery having a long shelf life, and more particularly to a sealing material having excellent impermeability to gases in each ridge.

[Technical background of the invention]

An air battery generally consists of a negative electrode made of zinc powder, an alkaline electrolyte such as potassium hydroxide, and a positive electrode such as activated carbon, which are housed in a positive electrode can that also serves as a positive terminal. At the bottom of the positive electrode can, at least 1 ml of positive electrode (activated carbon: adsorbs oxygen in the air and ionizes the oxygen to generate an electric current) Kjll* is provided.
Each air hole is perforated. The air holes are covered with water-resistant paper.

A sealing material made of polyethylene film, polypropylene film, etc. is applied from the outside to seal the air holes.

Efforts are made to prevent the electrolyte in the battery from drying out during battery storage, or to prevent the positive electrode's # gas ionization ability from decreasing due to the inflow of moisture or carbon dioxide from the outside.

When using the battery, the sealing material is peeled off to supply air to the positive electrode.

However, in conventional batteries with this type of structure, these sealing materials are not sufficiently impermeable to water vapor, **, and carbon dioxide gas, so during long-term storage, gases in the air can penetrate the sealing materials. It penetrates into the battery, resulting in a decrease in the battery's discharge capacity, an increase in internal resistance, and an increase or decrease in the electrolyte concentration due to water vapor transmission.

[Aim of the present invention] An object of the present invention is to solve the above-mentioned nine problems and provide an air battery whose discharge capacity does not decrease even when stored for a long period of time.

[Summary of the invention]

The present inventor has discovered that various thermoplastic resins, their water vapor,
Measure the oxygen and Iwashun gas permeability and obtain the results shown in Table 1.

These results show that polyvinyl heptatide and nylon 11.1 are superior in terms of water vapor transmission rate to polyethylene and polypropylene, which are commonly used as conventional sealants. Polytrifluorochloroethylene and vinyl chloride-vinylidene chloride copolymer are superior, and in terms of oxygen and carbon dioxide gas permeability, polyvinyl fluoride, polyvinylidene fluoride, nylon 6, and nylon 11m moisture-proof discovered that polytrifluorochloroethylene and vinyl chloride-vinylidene chloride copolymer were superior, and by appropriately combining membranes made of these materials and using nine composite membranes, the present invention was completed. Nine.

That is, the air battery of the present invention has a water vapor permeability of 900 or less, an oxygen permeability of 5 or less, and a jR11 gas permeability of 20.
Below (all the above numbers are in units).

It is XIO ICC-3/S@C・-・amHf. )
It is a composite metal made by laminating two or more types of M that satisfy at least one of the above conditions, and is characterized by having a structure in which the air holes are sealed with a sealing material that satisfies any of the above conditions t4. be.

The present invention will be explained below based on an illustrated embodiment.

In the figure, l is a positive electrode made of activated Dake powder.

Its upper surface is covered with an isolation layer 8 made of dragon Rohan.

It is in contact with an electrolyte holding material 3 made of a woven fabric (for example, polyand) or a porous structure (for example, polypropylene) that has excellent liquid retention properties and alkali resistance for holding an alkaline electrolyte. 4 is a negative electrode 1 which is usually made of gelled zinc. On the lower surface of the positive electrode 1 is an air-permeable membrane 5 made of, for example, Teflon. Air permeable membranes 6 made of cellulose nonwoven fabric with excellent air permeability are sequentially laminated.

All of these are stored in a positive electrode can γ with an open top.
For example, a negative electrode can 8 made of stainless steel is attached via a gasket 9.

Further, the bottom of the positive electrode can 7 in which the air hole IO is formed is covered with a sealant 11 (for example, pasted with an adhesive), so that the inside of the battery is in a sealed state.

The sealing material 11 is a composite membrane and has a low gas permeability.

That is, it is constructed by appropriately laminating two or more types of at which are made of a material having a small permeability in at least one of water vapor permeability, GI1 rate permeability, and carbon dioxide gas permeability. Therefore, the cough-tight art material 11 can exhibit low transmittance for any of water vapor, oxygen, and carbon dioxide gas. Each line that makes up the v41 sealing material 11 is! It is attached using means such as I adhesive, heat fusion, or ultrasonic welding.

Examples of materials with low water vapor permeability are 5. For example, polyvinyl heptadide, nylon, 11. Polyethylene chloride/1
Examples include thermoplastic resins such as vinyl chloride-vinylidene chloride copolymers. In addition, materials with low oxygen and carbon dioxide gas permeability include, for example, polyvinyl fluoride, polyvinylidene fluoride, nylon 6, nylon LT1 anti-effi chloride, polytrifluorochloroethylene, and vinyl chloride-vinylidene chloride copolymer. Examples include thermoplastic resins such as polymers.

As mentioned above, the air battery of the present invention uses a sealing material that has excellent impermeability to various gases.
Even if sold batteries are stored for a long period of time, gas

[Brief explanation of drawings]

The drawings are nine longitudinal sectional views showing one embodiment of the air battery of the present invention. 1... Positive electrode, 2... Isolation layer 3... Electrolyte holding material 4... Negative electrode 6... Air permeable membrane
6... Breathable membrane 7... Positive electrode can 8°°° Negative electrode can 9... Gasket 10... Air hole 11.
...Sealing material 11&...First layer 11b...Second layer 373-

Claims (1)

[Claims] Water vapor permeability is 900 or less, oxygen permeability is 5 or less, carbon dioxide gas permeability is 20 or less (the units of the above values are X 10" ce -am/see ・j ・aw
There is Hfte. ) A composite membrane is obtained by laminating two or more types of membranes that satisfy at least one of the above conditions, and the air holes are sealed with a sealing material that satisfies all of the above conditions. battery.