NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

PURPOSE:To provide a nonaqueous electrolyte secondary battery which is excellent at cycle life characteristic and low temperature characteristics by improving the solvent of electrolyte. CONSTITUTION:A nonaqueous electrolyte secondary battery includes a negative electrode 3 made by a carbonaceous material which can store and release lithium ions, nonaqueous electrolyte, and a positive electrode 1 made by an oxide containing lithium, and the solvent of the nonaqueous electrolyte is formed by mixing of ethylene carbonate, diethyl carbonate and propionic acid ethyl. The mixing ratio of the ethylene carbonate is 20 to 50% of the whole solvent and the mixing ratio of the propionic acid ethyl is 25 to 75% of chain ester. The nonaqueous electrolyte secondary battery excellent in cycle life and low temperature characteristics is thus obtained.