| 摘要 |
PURPOSE: A secondary battery is provided to additionally introduce a safety improver into a negative electrode, thereby improving safety of a battery at overcharging when internal temperature of the battery is increased at high temperature exposure. CONSTITUTION: A lithium ion secondary battery comprises a negative electrode. The negative electrode comprises a negative electrode layer including a negative electrode active material and a current collector. The negative electrode layer additionally includes alloy represented by chemical formula 1: M_aN_b or /and metal oxides represented by chemical formula 2: Toc. In the chemical formula 1, M is a metal which is not reactable with lithium ions, N is a metal which is reactable with lithium ions, 0<a/b<=5, and 0<b<=3. In the chemical formula 2, T is one selected from a transition metal group consisting of Mo, V, Ti, Cr, Y, Zr, Nb, and W; and 0<c<=3. [Reference numerals] (AA) Calory/Wg^-1; (BB) Example 7, 100% charged; (CC) Comparative example 1, 50% charged; (DD) Comparative example 1, 100% charged; (EE) Temperature/°C |
