Separator for use in non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery

摘要

A separator for use in a non-aqueous electrolyte secondary battery including a first porous layer (layer A) having a shutdown function which becomes substantially a non-porous layer at a high temperature, and a second porous layer (layer B) including an aramid resin and an inorganic material, wherein a ratio (TA/TB) of a thickness (TA) of the layer A relative to a thickness (TB) of the layer B is 2.5 or more and 13 or less.