LITHIUM ION SECONDARY BATTERY

摘要

Provided is a lithium ion secondary battery including: a positive electrode having a positive electrode active material layer disposed on a positive electrode current collector; a negative electrode having a negative electrode active material layer disposed on a negative electrode current collector; and an electrolyte solution. The positive electrode active material layer includes a positive electrode active material containing a lithium nickel composite oxide. The positive electrode contains an alkaline component by less than 1% relative to a weight of the positive electrode active material. The electrolyte solution includes an additive containing a cyclic carbonate additive with an unsaturated bond. A molar ratio of the cyclic carbonate additive with an unsaturated bond relative to a total molar amount of the additive is 78% or less.