| abstract |
In a lithium ion secondary battery according to an embodiment of the present invention, an electrode active material, a conductive assistant, and a binder component that bonds the conductive assistant to form a conductive path between the electrode active material and an electrode; And a binder composed of a melting point depressant that lowers the melting point of the binder component. The melting point depressant is a PTC function-imparting component that lowers the melting start temperature of the binder and imparts a PTC function to the lithium ion secondary battery. In the lithium ion secondary battery of the present invention, when a short-circuit heat is generated in the battery due to the conductive foreign matter, the binder around the foreign matter is melted to cut the conductive path. |