Hermetically sealed lithium secondary battery

A hermetically sealed lithium secondary battery comprising

• an electrode assembly that has a positive electrode and a negative electrode,
• a battery case that houses the electrode assembly and an electrolyte, and
• a current-interrupt mechanism that operates when the internal pressure of the battery case has risen, wherein
• the positive electrode comprising a positive electrode current collector and a positive electrode mixture layer formed on the positive electrode current collector and including a positive electrode active material, an electroconductive material, and a binder;
• the negative electrode comprising a negative electrode current collector and a negative electrode mixture layer formed on the negative electrode current collector and including a negative electrode active material and a binder;
• a positive electrode assist layer that includes an electroconductive material and a binder and that substantially does not contain a positive electrode active material is formed on the positive electrode current collector in at least a portion of an area adjacent to the positive electrode mixture layer;
• the positive electrode mixture layer is not formed on the area;
• and
• the electrolyte contains an overcharge inhibitor that generates a gas when a prescribed battery voltage is exceeded.