SEPARATOR FOR BATTERY, AND NON-AQUEOUS LITHIUM BATTERY

Disclosed is a separator for a battery, which comprises a porous film mainly composed of a polyolefin film, has heat resistance, and can improve battery properties. Specifically disclosed is a separator for a battery, which is characterized by having a layer mainly composed of a polyolefin resin, wherein at least one surface of the separator has an arithmetic average roughness (Ra) of 0.3µm or more.