| abstract |
Provided is a nonaqueous electrolyte secondary battery separator including a porous film containing polyolefin as a main component, the nonaqueous electrolyte secondary battery separator having a time until temperature rise cessation with respect to an amount of resin per unit area of 2.9 sec·m 2 /g to 5.7 sec·m 2 /g, the time being obtained in a case where the nonaqueous electrolyte secondary battery separator is impregnated with N-methyl pyrrolidine containing 3 wt % water and is subsequently irradiated, at an output of 1,800 W, with a microwave having a frequency of 2,455 MHz, the nonaqueous electrolyte secondary battery separator having an excellent initial rate characteristic and being capable of preventing a deterioration in rate characteristic which deterioration is caused by repeated charge and discharge. |