NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

Provided is a means capable of improving battery cycle durability in a non-aqueous electrolyte secondary battery having a capacity and a size which are assumed to increase the capacity and capable of suppressing occurrence of internal short-circuit.Disclosed is a non-aqueous electrolyte secondary battery including a power generating element, which includes a positive electrode, a negative electrode, and a separator including a resin film having a three-layer structure, a ratio of a rated capacity to a pore volume of a positive electrode active material layer being 2.08 Ah/cc or more, a ratio of a battery area to a rated capacity being 7 cm/Ah or more, and a rated capacity being 50 Ah or more, in which a value R of the separator represented by the following Formula 1 is 62 to 110:(provided that, the average pore diameter is 0.10 to 0.18 µm, the porosity is 0.43 to 0.65, the air permeability is 140 to 305 sec/100 ml, and the thickness is 11 to 25 µm).