LITHIUM ION SECONDARY BATTERY, AND SECONDARY BATTERY SYSTEM USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide: a lithium ion secondary battery which enables the materialization of a lithium ion secondary battery adaptive to a large-size electric device and arranged so that the balance among the capacity, safety and cycle characteristics can be achieved at a higher level than that achieved in the case of a compact electronic device; and a secondary battery system using such a lithium ion secondary battery.SOLUTION: A lithium ion secondary battery according to the present invention comprises: a positive electrode; a negative electrode; and a nonaqueous electrolytic solution. The nonaqueous electrolytic solution contains: a supporting electrolyte; a nonaqueous solvent; and a decomposition-inhibiting additive agent. The decomposition-inhibiting additive agent contains S-methyl methanethiosulfonate; the content of the S-methyl methanethiosulfonate is over 0.1 to 10 pts.mass to a total of 100 pts.mass of the supporting electrolyte and the nonaqueous solvent.