SEPARATOR AND NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

In a non-aqueous electrolyte secondary battery, a separator in which its dynamic hardness DH obtained when the load to an indenter reaches 12 kgf/cm2 is 1000 or more is used. This separator includes at least one porous layer X including a polyolefin, and at least one porous layer Y including a heat resistant resin. The porosity of the porous layer X is 35% or more and 65% or less. In a pore size distribution of the porous layer X measured with a mercury porosimeter, a ratio of pores having a pore size of 0.02 μm or more and 0.2 μm or less is 40 vol % or more relative to a total pore volume. The thermal deformation temperature of the heat resistant resin is 160° C. or more.