JPS62122057A - Button type battery - Google Patents

Abstract

PURPOSE:To increase ion conductivity and remarkably decrease internal resistance by mixing carbon fibers in an electrolyte holding material. CONSTITUTION:A positive active material 2 comprising a positive mix of silver oxide and graphite is filled in a positive case 1. Polyvinyl alcohol or non- acetalized polyvinyl alcohol serving as binder is dispersed in water. Acetalized polyvinyl alcohol and carbon fiber obtained by baking phenol resin are mixed to the above dispersion and stirred to uniformly disperse. This dispersion is made in paper with a metal net and dried to form a nonwoven fabric. This is used as an electrolyte holding material 4. The electrolyte holding material 4 is placed on a separator 3 obtained by laminating a porous polyethylene and cellophane. A negative active material 5 comprising gelled negative mix is filled in a negative cap 6. The negative cap 6 is fixed to the positive case 1 through a polyethylene gasket 7, and the opening of the positive case 1 is bent inward to seal and obtain a button type battery.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to button-type batteries used in electronic devices and wristwatches, and particularly relates to improvements in electrolyte holding materials used in button-type batteries.

[Conventional technology]

This type of button-type battery is small and has a high capacity, so it is suitable for long-term discharge of a relatively small current, and is used as a power source for pocket calculators, electronic wristwatches, and computer backup memories. In order to stabilize the battery discharge characteristics in such applications, graphite, carbon fiber, or carbon black can be added to improve the conductivity of the positive electrode active material, or conductive moisture can be added to the surface of the active material. The plan is to apply powder, nickel powder.

In addition, in order to reduce the resistance at the contact interface between the separator and the positive electrode mixture in order to reduce the internal resistance of the battery, the separator is sufficiently filled with electrolyte, and the electrolyte is also retained on the separator side of the positive electrode mixture. In order to enhance ionic conduction, an electrolytic solution is also injected and held between the separator and the positive electrode mixture.

Furthermore, in order to enhance the ionic conductivity of the electrolyte holding material in the battery, Japanese Patent Laid-Open No. 57-8'7066 proposes a method in which graphite powder is coated on kraft paper and polyvinyl alcohol is used as a binder.

[Problems to be solved by the invention] On the other hand, in the above-mentioned conventional proposal,
When applying the graphite powder described in Publication No. 6, the movement of the graphite powder may be slow if the material has a high fiber density such as kraft paper.
This is prevented because the HM gap is narrow, but polypropylene fibers and acetalized polyvinyl alcohol fibers are used as electrolyte holding materials.

As a result of manufacturing by mixing mercerized natural m-fibers, the air permeability is 10 to 30 times higher than the Gurley number, and the graphite powder is about several tens of microns to 100 microns, so it cannot become entangled between the fibers. It is impossible to hold the electrolyte in the electrolyte holding material. For this reason, the graphite powder is liberated into the electrolyte in the battery, making it impossible to maintain the ionic conductivity of the electrolyte holding material at a low level, resulting in a problem in which the internal resistance of the battery cannot be reduced.

SUMMARY OF THE INVENTION Therefore, in order to solve the problems of the conventional example, an object of the present invention is to reduce the internal resistance of a battery by including carbon fibers that are not released even during long-term storage in an electrolyte holding material.

[Means for Solving the Problems] In order to achieve the above object, the present invention will be described in detail. In the button type battery, the electrolyte holding material is made of a mixture of carbon fiber and synthetic resin fiber.

[Function] And the present invention uses polypropylene or polyethylene when paper-making an electrolyte holding material by the above-mentioned means.

Acetalized polyvinyl alcohol, nylon.

Tetrafluoroethylene (PTFE) is a fluororesin.

Tetrafluoroethylene-hexafluoropropylene copolymer (FE
P), When paper is made from synthetic fibers such as tetrafluoroethylene-bar 70-roalkyl vinyl ether copolymer (ETFE) with an average fineness of 0.3 denier or more and a 11 fiber length of 0.3n+m or more, the fibers are arranged in irregular directions. When dispersing synthetic fibers in a dispersion medium, the fibers of thermosetting resin such as acrylonitrile, epoxy, and phenolic resins with an average fiber size of 0.3 denyl or more should be roasted in the air or in an inert atmosphere. If the carbon fibers obtained by roasting are cut to have a fiber length Q of 3 mm or more and mixed with synthetic fibers in a dispersion medium, the paper becomes uniform and the carbon fibers and synthetic fibers intertwine with each other to make paper. Therefore, even when used as an electrolyte holding material, it does not become liberated in the electrolyte, and the ionic conductivity is increased by the carbon fibers, so the internal resistance of the battery can be reduced.

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

In the figure, 1 is a nickel-plated steel plate, and a positive electrode case 1 obtained by drawing a nickel-plated stainless steel plate is filled with a positive electrode active material 2 made of a positive electrode mixture of silver oxide and graphite. 3 is a separator made by laminating porous polyethylene and cellophane, and the upper surface of this separator 3 is coated with water as a dispersion medium and polyvinyl alcohol as a release adhesive or fibers with a length of 0.1 to 15 mm, preferably 0.5 to 15 mm. 5
Non-acetalized polyvinyl alcohol fibers having a diameter of 0.3 denier or more as synthetic fibers are dispersed in advance, and the fiber diameter is 0.3 denier or more, preferably 0.03 in.
5 to 1.0 denier, fiber length 0.1 to 1.5 mm, preferably 0.5 to 10 mm, and acetalized polyvinyl alcohol with a diameter of at least 0.3 denier, preferably 0.5 to 1.0 denier.
Carbon 1 is a roasted phenolic resin with a denier of 5 to 5.0 and a fiber density of 0.1 to 15 mm, preferably 0.5 to 10 mm! Carbon fibers or carbon fibers such as intermediate carbon fibers (trademark: Ketjen Black, manufactured by Exo Corporation), which have graphitized surfaces, are added to the dispersion medium and stirred for 10 to 20 minutes to uniformly disperse the carbon fibers. An electrolyte holding material 4 made of a nonwoven fabric made from a metal net and dried is placed thereon. Further, after mixing zinc powder and sodium polyacrylate, a negative electrode active material 5 made of a gel-like negative electrode mixture mixed with an electrolyte of 35% sodium hydroxide is applied to the inner surface of copper, stainless steel, and nickel. The clad plate with each plate crimped is filled into the drawn negative electrode cap 6, and the positive electrode case 1 and the negative electrode cap 6 are fitted together via the polypropylene insulating gasket 7, and the positive electrode case 1 is roughly connected to the negative electrode cap 6. The opening is bent inward and sealed to form a button-type battery.

Button type battery A uses the alkaline electrolyte obtained in the above example, the same electrolyte holding material as described in the example was used, and manganese dioxide was used as the positive electrode active material.

Lithium is used as the negative electrode active material, propylene carbonate and jetoxymethane are mixed in the electrolytic solution in a ratio of 1:1, and 0.
CR20 dissolved in lithium perchlorate at a concentration of 1 mol/historical
16-inch button-type lithium battery B, the button-type battery A
Assemble 50 each of B and conventional battery C2D in which carbon l1Iff is not mixed into the electrolyte holding material B.
The results of measuring the internal resistance of the battery using an H2 AC impedance meter are shown below. In addition, button type batteries A and C are 5
It is an R916 type silver battery.

Internal resistance ([(nu) Button type setting!!A 12.00C15,
8!1 8 8.7〃 D 11.5II [Effect of the invention 1 As detailed above, the product of the present invention improves ionic conductivity by incorporating carbon fiber into the electrolyte holding material, and significantly lowers the internal resistance of the battery. It is possible to provide a button-type battery that reduces energy consumption.

[Brief explanation of drawings]

The drawing is a cross-sectional view of a button-type battery in an embodiment of the present invention.

Claims (1)

[Claims] 1. A button type battery comprising a separator and an electrolyte holding material between a positive electrode active material and a negative electrode active material, wherein the electrolyte holding material is made of a material mixed with carbon fiber.