STRUCTURALLY STABLE, FUSIBLE BATTERY SEPARATORS AND METHOD OF MAKING SAME

摘要

The battery separator comprises a microporous polyolefinic membrane for maintaining an electrical resistance greater than 10,000 ohms/cm2> for at least 185[deg]C as measured at a scan rate of 60[deg]C/minute. An independent claim is also included for the production of a battery separator by: (a) extruding a cylindrical parison of a polymer film in a molten state having inner and outer surfaces; (b) applying a low temperature fluid stream to the inner and outer surfaces of the cylindrical parison; and (c) imparting porosity to the polymer film. The low temperature fluid stream is operative to quench the molten polymer film on both surfaces such that it is in a solidified state.