| 摘要 |
PURPOSE:To make it possible to maintain highly hermetical performance over a long period by using highly crystalline polypropylene of fixed density as an insulating packing material. CONSTITUTION:An insulating packing 7 is formed by molding highly crystalline polypropylene on a peripheral part of a sealing plate 2 by an injection molding method. The highly crystalline polypropylene used here is of block.copoly type of 0.905 g/cm<3> to 0.914 g/cm<3> in density. An enclosed battery which maintains highly hermetical performance over a long period can be obtained by the use of this insulating packing material 7. |
