| abstract |
To provide a means capable of suppressing the occurrence of internal short circuit in a power generating element when a battery is destroyed from the outside in a nonaqueous electrolyte secondary battery having a capacity and a size corresponding to a high energy density. n Provided is a nonaqueous electrolyte secondary battery which includes a power generating element including a positive electrode fabricated by forming a positive electrode active material layer containing a positive electrode active material on a surface of a positive electrode current collector, a negative electrode fabricated by forming a negative electrode active material layer containing a negative electrode active material on a surface of a negative electrode current collector, and a separator including a resin film and in which a volumetric energy density of the nonaqueous electrolyte secondary battery is 350 Wh/L or more and there is at least one direction having a tensile yield strength of 14 MPa or less at normal temperature, a tensile elongation at break of 100% or more at normal temperature, and a thermal shrinkage of 10% or less at the time of heating at 150° C. for 1 hour in a plane direction of the separator. |