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 (D) between the body portion of the current collecting member and the base portion of the lower insulating member in an axial direction (X) 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 (D) between the body portion of the current collecting member and the base portion of the lower insulating member in an axial direction (X) of the electrode lead-out hole , and the support member has a rigidity smaller than that of the sealing ring . <EOS>