A secondary battery, comprising: a cap plate provided with a first electrode terminal and a second electrode terminal; multiple electrode assemblies, each 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 connecting piece includes a first electrode terminal connecting portion, a first electrode tab connecting portion and a first fusing portion, the first electrode terminal connecting portion is fixed to the first electrode terminal, the first electrode tab connecting portion is fixed to the first electrode tab, and the first fusing portion is connected between the first electrode terminal connecting portion and the first electrode tab connecting portion; characterized in that the first connecting piece is wholly positioned at a side of the main body of the electrode assembly, the side of the main body of the electrode assembly faces the cap plate and is positioned in a height direction; the secondary battery further comprises an insulating piece adhered on a surface of the first connecting piece, the surface of the first connecting piece is connected with the first electrode tab; the first electrode tab connecting portion includes two first electrode tab connecting sub-portions and a first electrode tab jointing sub-portion; the two first electrode tab connecting sub-portions extend along a length direction, and each first electrode tab connecting sub-portion is fixed to and electrically connected with the first electrode tab of the corresponding electrode assembly; the first electrode tab jointing sub-portion extends along a width direction, and two ends of the first electrode tab jointing sub-portion are connected with the two first electrode tab connecting sub-portions respectively; the first electrode terminal connecting portion is positioned between the two first electrode tab connecting sub-portions and extends along the length direction; the first fusing portion extends along the length direction and is connected between the first electrode tab jointing sub-portion and the first electrode terminal connecting portion; the insulating piece at least covers two edges of the first electrode terminal connecting portion which are respectively positioned at two sides of the first electrode terminal connecting portion along the width direction so as to avoid the first electrode tab directly contacting the edges. a cap plate provided with a first electrode terminal and a second electrode terminal; multiple electrode assemblies, each 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 connecting piece includes a first electrode terminal connecting portion, a first electrode tab connecting portion and a first fusing portion, the first electrode terminal connecting portion is fixed to the first electrode terminal, the first electrode tab connecting portion is fixed to the first electrode tab, and the first fusing portion is connected between the first electrode terminal connecting portion and the first electrode tab connecting portion; characterized in that the first connecting piece is wholly positioned at a side of the main body of the electrode assembly, the side of the main body of the electrode assembly faces the cap plate and is positioned in a height direction; the secondary battery further comprises an insulating piece adhered on a surface of the first connecting piece, the surface of the first connecting piece is connected with the first electrode tab; the first electrode tab connecting portion includes two first electrode tab connecting sub-portions and a first electrode tab jointing sub-portion; the two first electrode tab connecting sub-portions extend along a length direction, and each first electrode tab connecting sub-portion is fixed to and electrically connected with the first electrode tab of the corresponding electrode assembly; the first electrode tab jointing sub-portion extends along a width direction, and two ends of the first electrode tab jointing sub-portion are connected with the two first electrode tab connecting sub-portions respectively; the first electrode terminal connecting portion is positioned between the two first electrode tab connecting sub-portions and extends along the length direction; the first fusing portion extends along the length direction and is connected between the first electrode tab jointing sub-portion and the first electrode terminal connecting portion; the insulating piece at least covers two edges of the first electrode terminal connecting portion which are respectively positioned at two sides of the first electrode terminal connecting portion along the width direction so as to avoid the first electrode tab directly contacting the edges.