Polyolefin-based film and preparation method thereof, separator, secondary battery, and electric apparatus

Abstract

A polyolefin-based film is described. Through optimization of tortuosity of a pore structure in the polyolefin-based film, the polyolefin-based film has a uniform pore structure, thereby improving consistency of the base film, reducing performance deviation of the base film, and effectively ensuring air permeability of the base film. Additionally, the polyolefin-based film of this application is ultra-thin. For every 1 μm reduction in thickness, energy density of a battery cell can increase by approximately 0.7%. Therefore, with the thickness controlled to be below 7 μm, the energy density of the battery cell is improved. When the polyolefin-based film is used as a separator in a battery, electrical performance of the battery can be improved, including reducing battery internal resistance, direct current resistance, self-discharge rate, short-circuit rate, and the like. This application further relates to a preparation method of the polyolefin-based film, a separator, a secondary battery, and an electric apparatus.

Dependencies are inferred from the claim text.