A secondary battery, characterized in that, comprising: a cap assembly, comprising: a cap plate provided with an electrode lead-out hole; an electrode terminal, adapted to cover the electrode lead-out hole; a sealing ring disposed between the cap plate and the electrode terminal; and a lower insulating member comprising a base portion and a protruding portion connected to each other, wherein the base portion is located at a lower side of the cap plate and has a thickness of 0.01 mm to 10 cm, and the protruding portion is at least partially located in the electrode lead-out hole; a current collecting member comprising a body portion and an extending portion connected to each other, wherein the body portion is located below the base portion of the lower insulating member, and the extending portion is configured to extend into the electrode lead-out hole and is connected to the electrode terminal; and a support member disposed between the body portion of the current collecting member and the base portion of the lower insulating member, wherein the support member is formed as an elastic member and has a thickness in a free state greater than or equal to a distance between the body portion of the current collecting member and the base portion of the lower insulating member in an axial direction of the electrode lead-out hole, and the support member has a rigidity smaller than that of the sealing ring. a cap assembly, comprising: a cap plate provided with an electrode lead-out hole; an electrode terminal, adapted to cover the electrode lead-out hole; a sealing ring disposed between the cap plate and the electrode terminal; and a lower insulating member comprising a base portion and a protruding portion connected to each other, wherein the base portion is located at a lower side of the cap plate and has a thickness of 0.01 mm to 10 cm, and the protruding portion is at least partially located in the electrode lead-out hole; a cap plate provided with an electrode lead-out hole; an electrode terminal, adapted to cover the electrode lead-out hole; a sealing ring disposed between the cap plate and the electrode terminal; and a lower insulating member comprising a base portion and a protruding portion connected to each other, wherein the base portion is located at a lower side of the cap plate and has a thickness of 0.01 mm to 10 cm, and the protruding portion is at least partially located in the electrode lead-out hole; a current collecting member comprising a body portion and an extending portion connected to each other, wherein the body portion is located below the base portion of the lower insulating member, and the extending portion is configured to extend into the electrode lead-out hole and is connected to the electrode terminal; and a support member disposed between the body portion of the current collecting member and the base portion of the lower insulating member, wherein the support member is formed as an elastic member and has a thickness in a free state greater than or equal to a distance between the body portion of the current collecting member and the base portion of the lower insulating member in an axial direction of the electrode lead-out hole, and the support member has a rigidity smaller than that of the sealing ring.