NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

Provided is a nonaqueous electrolyte secondary battery including a flat wound electrode body (20). The flat wound electrode body (20) has a flat portion (P), a first R portion (R 1 ), and a second R portion (R 2 ). The second R portion (R 2 ) is provided on a bottom side of a battery case (10) when a nonaqueous electrolytic solution is put into the battery case (10) at least in a battery construction step. Opposite end portions (27) of the second R portion (R 2 ) in the winding axial direction are squashed in a thickness direction of the electrode body to a larger extent than opposite end portions of the first R portion (R 1 ) in the winding axial direction.