Top cap assembly, secondary battery, battery module and device

A top cap assembly for a secondary battery, the top cap assembly comprising

• a top cap plate, having an electrode lead-out hole;
• an electrode terminal, arranged at the top cap plate and covering the electrode lead-out hole;
• a current collecting member, wherein the current collecting member comprises a convex portion having an accommodating cavity, at least part of the convex portion is arranged in the electrode lead-out hole, and welded and connected to the electrode terminal to form a welding portion facing the accommodating cavity, the current collecting member has a connecting hole, and the connecting hole has a first opening formed on a surface of the current collecting member away from the electrode terminal;
• an insulating protection member, wherein the insulating protection member is arranged at a side of the current collecting member away from the electrode terminal, the insulating protection member comprises a shielding portion and a connecting portion connected with the shielding portion, the shielding portion shields the welding portion, and at least part of the connecting portion extends into the connecting hole through the first opening and is connected and fixed to the current collecting member.