| abstract |
Considering that battery separators will require further thinner materials and lower costs in the future, a battery separator of the present invention, in which multi-layer polyolefin porous membrane with exceptionally high peel strength against a modified porous layer, suitable for high-speed processing during slit process and battery assembly process, and suitable for laminating on a multi-layer modified porous layer, and a multi-layer modified porous layer are laminated, is provided. A multi-layer polyolefin porous membrane comprising at least two or more layers, the multi-layer polyolefin porous membrane having a shut-down temperature in a range of 128 to 135° C., a rate of increase in air permeation resistance from 30° C. to 105° C. scaled to 20 μm thickness less than 1.5 sec/100 cc Air/° C., and a thickness not more than 20 μm. |