Lithium secondary battery and manufacturing method thereof

摘要

A lithium secondary battery, includes: a cylindrical battery case (16) provided with electrode caps at both end portions thereof; an electrode body (1) impregnated with a nonaqueous electrolyte solution and contained in the battery case and including a positive electrode, a negative electrode, and a separator, the positive electrode and the negative electrode being wound or laminated through the separator; and moreover, an elastic body (23) disposed between the battery case (16) and the electrode caps with portions in which the battery case (16) contacts the elastic body (23) being brought into press-contact to form a caulked portion to seal the battery case (16). With Rbody (mm) being diameter of a body part of the battery case (16), Rtop (mm) being diameter of the caulked portion, Rbody and Rtop fulfill relationship of Rbody > Rtop. Improvement in long period stability and reliability can be planned by intensifying the caulking between the battery case and the electrode cap and by removing the caulked gap between the battery case and the electrode cap so as to suppress leakage of the electrolyte solution.