Cap assembly and secondary battery

A secondary battery, comprising:

• a case provided with an opening;
• an electrode assembly accommodated in the case;
• and,
• a cap assembly, comprising:
• a cap plate, provided with an electrode lead-out hole;
• an electrode terminal, covering the electrode lead-out hole and comprising a main body, wherein the main body is provided with a recess on a side wall;
• an isolating member comprising a receiving portion, wherein the main body is received in the receiving portion;
• and
• a protrusion, connected to an inner wall of the isolating member and extending towards an axis of the electrode lead-out hole,
• wherein the protrusion is received in the recess so as to prevent the main body from rotating relative to the isolating member,
• wherein the cap assembly is configured to cover the opening to close the case with the electrode assembly therein, and
• wherein the cap assembly further comprises a connecting member, which is welded with the cap plate and is connected with the main body through the isolating member, the connecting member comprises a first connecting portion located on a side of the main body facing away from the cap plate, and a part of the isolating member is located between the first connecting portion and the cap plate.