NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery with long storage life and high capacity. SOLUTION: In a sealed nonaqueous electrolyte secondary battery formed by pouring a nonaqueous electrolyte containing a lithium salt in a battery container, then sealing the battery container, the content of free acid contained in the nonaqueous electrolyte is controlled so as not to exceed 300 ppm three years after sealing.