| 摘要 |
PROBLEM TO BE SOLVED: To provide a fine porous membrane which is capable of suppressing gases generated during storage at high temperatures and deterioration of discharge capacity as well as keeping physical property needed as a high performance separator for high capacity rechargeable lithium-ion batteries. SOLUTION: This fine porous membrane contains polyethylene in an amount of not less than 50% by weight, and a content of polyethylene in an area close to the surface of the membrane is less than the average in the entire membrane. COPYRIGHT: (C)2004,JPO |
