Patent ID: 10135054

Abstract:
A battery separator is disclosed. The battery separator includes a polyolefin porous membrane which has a plurality of protrusions including a polyolefin. The protrusions are interspersed randomly on at least one surface of the polyolefin porous membrane at a density of not less than 3 protrusions/cm2 and not greater than 200 protrusions/cm2. The protrusions have a size W, where 5 μm≤W≤50 μm, and the protrusions have a height H, where 0.5 μm≤H. The battery separator also includes a modified porous layer, including a fluorine-based resin, and a plurality of inorganic particles laminated on the at least one surface of the polyolefin porous membrane. A concentration of the inorganic particles is not less than 40 wt. % and is less than 80 wt. %.