Molded electrode, method for production thereof, and secondary battery using thereof

Inactive Publication Date: 2005-01-06
TOKIN CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

In view of the above-mentioned problem of the prior art, the object of the present invention is to provide a secondary battery using a polymer active material, which has a large energy density and a large power density and which has a high freedo

Problems solved by technology

In the above production method, however, during the drying of the coating film of electrode mixture formed on the current collector, the solvent contained in the coating film vaporizes, which incurs the contraction of the film and often generates cracks in the film.
This phenomenon is more striking when the coating film is formed in a larger thickness; therefore, it is difficult to form a thick film.
In the above production method, the volume of the current collector in the battery is inevitably large; therefore, it is difficult to increase the amount of the active material to a level higher than now, within the restraint of limited battery volume.
Thus, in the conventional produc

Method used

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  • Molded electrode, method for production thereof, and secondary battery using thereof
  • Molded electrode, method for production thereof, and secondary battery using thereof
  • Molded electrode, method for production thereof, and secondary battery using thereof

Examples

Experimental program
Comparison scheme
Effect test

example 1

In this Example, a current collector sheet and an electrode material were hot-pressed into a one-piece molded electrode having a structure of FIG. 1; and a battery was constituted using the molded electrode as the positive electrode.

Production of Battery of Example 1

First, description is made on production of a battery in the following (1) to (4).

(1) Production of Positive Electrode Mixture

An aqueous solution of 1 M ammonium peroxodisulfate and an aqueous solution of 1 M of an aniline monomer were mixed with stirring at room temperature for 3 hours to allow a polymerization reaction to proceed slowly. The polymerization reaction product obtained was ground to 60 mesh or below using an agate mortar. Thereto was added an aqueous solution of 1 M of paratoluenesulfonic acid. The mixture was stirred at 65° C. for 12 hours to dope the polyaniline (PAn) with a paratoluenesulfonic acid anion (pTOS−), whereby a PAn / pTOS− powder having conductivity was obtained.

There were mixed the...

example 2

In Example 2, hot pressing for one-piece molding of current collector and electrode material was conducted 3 times to produce a molded electrode having 3 current collector sheets in the thickness direction. A battery was constituted by using the molded electrode as a positive electrode.

First, a one-piece molded positive electrode consisting of an electrode material and a current collector was formed using the same electrode material and same manner as in Example 1. With this one-piece electrode being left in the die used, the same nickel current collector as used in Example 1 was placed in the die. Then, the same positive electrode mixture as used in Example 1 was filled uniformly, and hot pressing was conducted under the same conditions as in Example 1. This operation was conducted once more to obtain a one-piece molded electrode containing three current collectors. Then, the terminal portions of the nickel current collectors were welded to form one terminal for positive electro...

example 3

The operation of Example 3 was the same as in Example 1 except that the positive electrode material was a polycyanoindole, the neutral electrolytic solution was an aqueous solution containing 1 M of zinc sulfate, and the negative electrode was metal zinc.

First, an ethanol solution of 1 M of iron sulfate and an aqueous solution of 1 M of cyanoindole were mixed with stirring at room temperature for 3 hours, to allow a polymerization reaction to proceed slowly. The polymerization product (a polycyanoindole) obtained by filtration and washing with DMF was ground to 60 mesh or below using an agate mortar. Since the polycyanoindole had been doped with sulfate ion during the polymerization reaction, no doping was applied to the polycyanoindole.

Using this polycyanoindole powder doped with sulfate ion and employing the same manner as in Example 1, a powdery electrode mixture was obtained which consisted of the polycyanoindole, a vapor phase-grown carbon and butyl butylphthalylglycolate....

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Abstract

A molded electrode into one-piece is obtained by hot pressing an electrode material obtained by mixing a polymer active material, a conductivity-enhancing agent and a plasticizer, and a current collector sheet. The electrode structure permits significant freedom when designing a secondary battery which uses this electrode with a high energy density and a high power density.

Description

BACKGROUND OF THE INVENTION (1) Field of the Invention The present invention relates to a secondary battery using a polymer active material. More particularly, the present invention relates to the composition and structure of an electrode using a polymer active material, as well as to a method for production of the electrode. (2) Description of the Prior Art Secondary batteries using a polymer material (e.g. a polyaniline or a polypyrrole) as an active material have been developed. In typical method for producing a electrode in such a secondary battery, a polymer active material, a conductivity-enhancing agent and an organic binder (e.g. a polytetrafluoroethylene) are kneaded using an appropriate solvent to obtain an electrode mixture; this electrode mixture is coated on a current collector (e.g. a metal foil), followed by drying, to form a film (or layer) of ordinarily about 20 to 100 μm in thickness on the current collector., The resulting electrode is used as a positive elect...

Claims

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Application Information

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IPC IPC(8): H01M4/02H01M4/04H01M4/137H01M4/1399H01M4/60H01M10/05H01M10/36
CPCH01M4/04H01M4/137H01M4/606Y02E60/122H01M10/05H01M10/36H01M4/608Y02E60/10
Inventor FUJIWARA, MASAKINAKAGAWA, YUJIKUROSAKI, MASATOKANEKO, SHINAKOHARADA, GAKUNISHIYAMA, TOSHIHIKO
Owner TOKIN CORP
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