| 摘要 |
PROBLEM TO BE SOLVED: To provide a porous membrane comprising silane crosslinked polyethylene, high in obstacle to conductive particulates such as active materials, having low prermeation resistance of an electrolyte ion and characteristics tolerant to a tension upon manufacturing a battery, and further an excellent heat resistance in such a manner that even if an electrode surface is uneven, a projection does not pass through a separator and a short-circuit is not made; a separator for the battery comprising the porous membrane, and to provide a manufacturing method of them. SOLUTION: This comprises silane crosslinked polyethylene. A porosity ratio is 20 to 60%. The maximum pore size is equal to or less than 1μm<2> . An air permeability (Gurley value) is equal to or less than 1000 sec. The number of projections having a height which is equal to or larger than twice the average thickness is equal to or less than 10 per area of 1 m<2> of the porous membrane surface. A raw material is a mixture resin comprising the silane denaturation polyethylene and organic low molecule indicative of a compatibility therewith. An extruding step, a crosslinking step, and an extracting step are included. |
