| 摘要 |
PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery which enables the improvement in the thermal stability when a battery is stored in a high-temperature condition and battery characteristics.SOLUTION: A lithium ion secondary battery comprises: a positive electrode active material including a lithium nickel complex oxide; and a nonaqueous electrolyte which contains at least one disulfonate selected from a group consisting of a cyclic disulfonate ester and a chain disulfonate ester, and at least one carbonate selected from a group consisting of a vinylene carbonate and a vinyl ethylene carbonate and having an unsaturated bond. The nonaqueous electrolyte includes 0.05 mass % or more and 0.5 mass% or less of the disulfonate to the total mass of the nonaqueous electrolyte, and 0.2 mass% or more and 1.5 mass% or less of the carbonate having an unsaturated bond to the total mass of the nonaqueous electrolyte. |
