| 摘要 |
PROBLEM TO BE SOLVED: To provide a metal ion secondary battery separator ensuring excellent micro short circuit prevention and high rate characteristics, when manufacturing a metal ion secondary battery separator having especially excellent heat resistance.SOLUTION: In a metal ion secondary battery separator where an inorganic pigment is carried on a nonwoven fiber base material, melting point of the constituent fiber of the nonwoven fiber base material is 200°C or more, dehydration temperature of the inorganic pigment is 250°C or more, and the ratio s/n of the maximum pore diameter s of the separator for the maximum pore diameter n of the nonwoven fiber base is 1/5-1/20. |
