SEPARATOR FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERIES, AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

[Problem] To provide: a separator which contains glass fibers as a constituent material and has a strength sufficient for preventing the occurrence of a break or a crack during the production of a wound battery, and which enables the achievement of high discharge rate characteristics; and a nonaqueous electrolyte secondary battery. [Solution] A separator for nonaqueous electrolyte secondary batteries, which is mainly composed of glass fibers, and which is characterized by having a thickness of 45 μm or less, a winding failure strength of 1.2 kg or more, a short-circuit resistance of 0.7 kgf or more; a void fraction of 60% or more; a Gurley air permeability of 3 s/100 mL or less, and an average pore diameter of from 1 μm to 5 μm (inclusive).