The utility model provides a secondary battery. The utility model discloses a secondary battery, include: top cap piece, first ploe post, second ploe post, utmost point ear pad board, naked electric core, first ploe ear and second ploe ear, first ploe post and second ploe post all set up on the top cap piece, and utmost point ear pad board is rectangular shape platelike structure, and utmost point ear pad board is located between top cap piece and the naked electric core, and the first ploe ear includes connecting portion, folding portion and weld part, and connecting portion are located the upside of utmost point ear pad board, welding?parts in the downside of utmost point ear pad board, and connecting portion are connected with naked electric core, weld part and first ploe support connnection, folding portion walks around utmost point ear pad board and connects connecting portion and weld part, the second ploe post passes through the second ploe ear and is connected with naked electric core. The utility model discloses an and welding of producing during the welding of utmost point ear is printed and the extremely connecting portion and the isolation of the physics between the naked electric core of ear, has improved the performance of battery, and then has prolonged the life's of battery effect.