A secondary battery, comprising: a case; an electrode assembly, accommodated in the case and comprising a main body and a tab connected to the main body; a cap plate, coupled to the case; an electrode terminal, located on an outer side of the cap plate and comprising a first metal layer and a second metal layer disposed one on top of another, wherein the second metal layer is located on a side of the first metal layer away from the cap plate, and the first metal layer and the second metal layer are made of different materials, and wherein the electrode terminal is provided with a stepped hole, which comprises a first hole segment penetrating through the first metal layer and a second hole segment penetrating through the second metal layer and extending into the first metal layer; and a current collecting member, connected between the tab and the electrode terminal, wherein the current collecting member comprises an extending portion extending toward the electrode terminal and protruding into the first hole segment, and directly connected to the first metal layer, and the first metal layer is made of the same material as the current collecting member, wherein the second hole segment has a diameter larger than that of the first hole segment, and the extending portion is welded to the first metal layer, characterised in that the current collecting member further comprises a connecting portion located on an inner side of the cap plate and directly connected to the tab, a projection connected between the extending portion and the connecting portion and a support portion connected to the extending portion, and a recess is formed on a side of the projection away from the electrode terminal by forming the projection; the projection is provided with a through hole and the extending portion passes through the through hole; the support portion is received in the recess and fixes the connecting portion; and wherein the support portion is received in the recess and extends beyond an inner wall of the through hole in a radial direction of the through hole, and the projection is clamped by the support portion and the electrode terminal together. a case; an electrode assembly, accommodated in the case and comprising a main body and a tab connected to the main body; a cap plate, coupled to the case; an electrode terminal, located on an outer side of the cap plate and comprising a first metal layer and a second metal layer disposed one on top of another, wherein the second metal layer is located on a side of the first metal layer away from the cap plate, and the first metal layer and the second metal layer are made of different materials, and wherein the electrode terminal is provided with a stepped hole, which comprises a first hole segment penetrating through the first metal layer and a second hole segment penetrating through the second metal layer and extending into the first metal layer; and a current collecting member, connected between the tab and the electrode terminal, wherein the current collecting member comprises an extending portion extending toward the electrode terminal and protruding into the first hole segment, and directly connected to the first metal layer, and the first metal layer is made of the same material as the current collecting member, wherein the second hole segment has a diameter larger than that of the first hole segment, and the extending portion is welded to the first metal layer, characterised in that the current collecting member further comprises a connecting portion located on an inner side of the cap plate and directly connected to the tab, a projection connected between the extending portion and the connecting portion and a support portion connected to the extending portion, and a recess is formed on a side of the projection away from the electrode terminal by forming the projection; the projection is provided with a through hole and the extending portion passes through the through hole; the support portion is received in the recess and fixes the connecting portion; and wherein the support portion is received in the recess and extends beyond an inner wall of the through hole in a radial direction of the through hole, and the projection is clamped by the support portion and the electrode terminal together.