POLYOLEFIN MICROPOROUS MEMBRANE, PRODUCTION METHOD FOR POLYOLEFIN MICROPOROUS MEMBRANE, BATTERY SEPARATOR, AND BATTERY

摘要

Provided are a polyolefin microporous membrane capable of achieving a low shutdown temperature while keeping air permeation resistance sufficiently low, and a method for producing the polyolefin microporous membrane. The polyolefin microporous membrane according to the present invention has, when a temperature is raised to 230 °C at a temperature rise rate of 10 °C/min in differential scanning calorimetry (DSC), a ratio of a melting heat quantity (”H Tm0 ) of equal to or larger than 95% at temperatures lower than an equilibrium melting point of polyethylene, relative to 100% of the total melting heat quantity (”H all ).