LITHIUM ION SECONDARY BATTERY

To provide a lithium ion secondary battery having high characteristics and arranged so as to be able to safely stop in the event of abnormal temperature increase.SOLUTION: A lithium ion secondary battery comprises: a positive electrode mixture having a positive electrode active material; a negative electrode mixture having a negative electrode active material; and a ceramic layer between the positive and negative electrode mixture layers, which is provided in the state of being applied to the positive or negative electrode mixture layer. The ceramic layer has ceramic particles and a gas generating agent. When the ceramic layer is divided to a part on a positive electrode mixture layer side and a part on a negative electrode mixture layer side, the ratio A/B of an amount A of the gas generating agent that is present in the part on the positive electrode side and an amount B of the gas generating agent that is present in the part on the negative electrode side is in a range given by 0.5≤A/B≤2.0.SELECTED DRAWING: Figure 3 【課題】本発明の目的は、特性が高く、異常昇温時に安全に停止するリチウムイオン二次電池を提供することである。【解決手段】正極活物質を有する正極合剤と、負極活物質を有する負極合剤と、前記正極合剤層と前記負極合剤層の間にはセラミック層が、前記正極合剤層または、前記負極合剤層に塗布された状態で設けられ、前記セラミック層は、セラミック粒子とガス発生剤とを有し、前記セラミック層を前記正極合剤層側と前記負極合剤層側とに分割した時に、正極側に存在するガス発生剤の量Ａと、負極側に存在するガス発生量Ｂとの比率Ａ／Ｂは、０．５≦Ａ／Ｂ≦２．０の範囲であるリチウムイオン二次電池。【選択図】図３