Cover plate assembly, battery cell, battery and electric equipment

The utility model discloses a cover plate assembly, the cover plate assembly comprises a cover plate, a solder layer and a sealing member, the cover plate is provided with a liquid injection hole and a welding groove, and the welding groove is arranged around the liquid injection hole; the solder layer is located in the welding groove; the sealing piece is contained in the welding groove and seals the liquid injection hole, and the welding flux layer is connected to the sealing piece and the welding groove so that the sealing piece can be connected with the cover plate in a sealed mode. The utility model further discloses a battery cell provided with the cover plate assembly, a battery and electric equipment.