NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY AND METHOD FOR PRODUCING NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY

Provided is a technique for suppressing the formation of black regions in a wound electrode body. The production method disclosed herein is a method for producing a non-aqueous electrolyte secondary battery that includes a wound electrode body, a non-aqueous electrolyte, and a battery case. This production method includes the following steps: an assembling step S of placing the wound electrode body and the non-aqueous electrolyte in the battery case to construct a secondary battery assembly; a first step S of performing initial charging on the secondary battery assembly; and a second step S of setting the temperature of the wound electrode body to 50° C. or lower and keeping this state for at least 72 hours after the first step.