| 摘要 |
PURPOSE:To improve the liquid leak proof of a cell, by heat-treating a gasket, which is made of a synthetic resin and used for a sealed portion, in vacuo or in an atmosphere of an inert gas to increase its crystallization degree. CONSTITUTION:A positive electrode compound 2 is filled into a positive electrode can 1, and on top of this compound a separator 3 is placed. Then a negative electrode terminal plate 5, in which a negative electrode compound 4 is filled, is fitted into the opening of the positive electrode can 1 by interposing an annular gasket 6 made of a synthetic resin and having an L-shaped cross section. This unit is hermetically sealed to construct a button-shaped cell. The gasket 6 for said cell is subjected to a heat treatment under vacuum or in an inert gas to increase its crystallization degree. A temperature for said heat treatment shall be above the glass transition temperature of the synthetic resin used, but not higher than its melting point. It is preferably above 100 deg.C. The crystallization degree, through it is different according to the synthetic resin to be used, is preferably, for instance, about 75-90% for polyethylene and about 68-90% for polypropylene. |
