NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY

PROBLEM TO BE SOLVED: To provide a high-capacity non-aqueous electrolyte secondary battery that is excellent in safety.SOLUTION: In a non-aqueous electrolyte secondary battery, a wound electrode body is formed by winding a positive electrode, a negative electrode, and a separator, and is housed in a bottomed outer can having an opening. The opening is sealed by a sealing body. Above the wound electrode body, the non-aqueous electrolyte secondary battery also has a current breaking mechanism that is activated by a rise in battery internal pressure. A bottom surface of the outer can is parallel to a winding axis direction of the wound electrode body. The thickness of the negative electrode at a charge depth of 100% is 130% or less of the thickness of the same at the time of assembly of the non-aqueous electrolyte secondary battery is assembled. Maximum width, perpendicular to the winding axis direction, of the wound electrode body at the time of assembly is 90% to 98% of a distance from the bottom surface of the outer can to the current breaking mechanism. The non-aqueous electrolyte secondary battery has a capacity of 4 Ah or more.