A secondary battery, comprising: a cap plate provided with a first electrode terminal and a second electrode terminal; an electrode assembly comprising a main body, a first electrode tab provided to the main body and a second electrode tab provided to the main body; and a first connecting piece connected between the first electrode tab and the first electrode terminal; the second electrode tab being electrically connected with the second electrode terminal; wherein the first electrode tab includes a first connecting portion and a first bending portion, the first connecting portion is welded with the first connecting piece, and the first bending portion is bent downwardly and connected between the main body of the electrode assembly and the first connecting portion;the secondary battery further comprises a first insulating adhesive adhered on weld zones which are formed during welding of the first connecting portion and the first connecting piece and face the main body of the electrode assembly; wherein the first connecting portion is positioned below the first connecting piece in a height direction, and an upper surface of the first connecting portion is securely connected with a lower surface of the first connecting piece; wherein the secondary battery further comprises a first welding protecting piece provided on the first connecting portion; and the first welding protecting piece, the first connecting portion and the first connecting piece are securely connected together by ultrasonic welding; the first insulating adhesive is adhered on the weld zones which are formed during the ultrasonic welding and face the main body of the electrode assembly; wherein an angle between the first connecting portion and the first bending portion ranges from 0 degrees to 45 degrees. a cap plate provided with a first electrode terminal and a second electrode terminal; an electrode assembly comprising a main body, a first electrode tab provided to the main body and a second electrode tab provided to the main body; and a first connecting piece connected between the first electrode tab and the first electrode terminal; the second electrode tab being electrically connected with the second electrode terminal; wherein the first electrode tab includes a first connecting portion and a first bending portion, the first connecting portion is welded with the first connecting piece, and the first bending portion is bent downwardly and connected between the main body of the electrode assembly and the first connecting portion;the secondary battery further comprises a first insulating adhesive adhered on weld zones which are formed during welding of the first connecting portion and the first connecting piece and face the main body of the electrode assembly; wherein the first connecting portion is positioned below the first connecting piece in a height direction, and an upper surface of the first connecting portion is securely connected with a lower surface of the first connecting piece; wherein the secondary battery further comprises a first welding protecting piece provided on the first connecting portion; and the first welding protecting piece, the first connecting portion and the first connecting piece are securely connected together by ultrasonic welding; the first insulating adhesive is adhered on the weld zones which are formed during the ultrasonic welding and face the main body of the electrode assembly; wherein an angle between the first connecting portion and the first bending portion ranges from 0 degrees to 45 degrees.