RECTANGULAR NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

[Problem] To provide a rectangular nonaqueous electrolyte secondary battery including a flat wound electrode body, in which the reaction of an additive agent in a nonaqueous electrolyte is stimulated during overcharging and stability during the overcharging is improved. [Solution] A rectangular nonaqueous electrolyte secondary battery (10) of the present invention includes a flat wound electrode body (14). A nonaqueous electrolyte contains an additive agent consisting of 0.5 to 4 mass% of 1, 3-dioxane and at least one type of aromatic compound selected from 0.5 to 4 mass% of a cycloalkyl benzene compound and a compound having quaternary carbon adjacent to a benzene ring. The flat wound electrode body (14) has an unpressed portion formed thereon, which accounts for 0.1 to 0.9.