| 摘要 |
PROBLEM TO BE SOLVED: To prevent generation of short-circuit caused by a surface disorder resulting from a thin structure by composing the subject separator of two or more kinds of polyolefin resin constituent, and performing paper making together with polyolefin fibers by a wet paper making method after a split type composite fiber capable of being divided into fine fibers is preliminarily devided. SOLUTION: It is preferable that a separator contains 5-60 wt.% of split type composite fiber whose length is 1-4 mm, and 40-95 wt.% of polyolefin fiber. The split type composite fiber is preferably composed of polyethylene/ polypropylene, polypropylene/ethylene vinyl alcohol copolymer or the like. The polyolefin fiber is preferably of a side-by-side type or a sheathed type composite fiber, a synthesized pulp of olefin resin monofiber and fine olefin resin, and is made of polyethylene, polypropylene. copolymer of propylene and ethylene, and resin mainly composed of them. Accordingly, the separator having a high liquid reserving characteristic and absorption characteristic, and less battery performance is provided. |
