NON-AQUEOUS ELECTROLYTIC SOLUTION SECONDARY BATTERY, SEPARATOR FORMED OF NON-AQUEOUS ELECTROLYTIC SOLUTION SECONDARY BATTERY, AND METHOD OF MANUFACTURING NON-AQUEOUS ELECTROLYTIC SOLUTION SECONDARY BATTERY

Provided are a non-aqueous electrolytic solution secondary battery, a separator formed of the non-aqueous electrolytic solution secondary battery, and a method of manufacturing the non-aqueous electrolytic solution secondary battery. The non-aqueous electrolytic solution secondary battery includes a positive electrode, a negative electrode, and a composite separator that is disposed between the positive electrode and the negative electrode, in which in the composite separator, a thermally expandable capsule is sandwiched in an interlayer of a laminate formed of at least two separator sheets.