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 surrounds the liquid injection hole; the sealing piece is contained in the welding groove and seals the liquid injection hole, the welding groove comprises a welding face, the welding face comprises a welding bottom face and a welding inner circumferential face, the welding inner circumferential face is connected to the outer edge of the welding bottom face, and the sealing piece comprises an inner surface facing the welding bottom face and an outer side face surrounding the welding bottom face. A first gap is formed between the welding inner peripheral surface and the outer side surface; the welding flux layer is contained in the first gap and connected to the welding inner circumferential face and the outer side face so as to be connected with the cover plate and the sealing piece in a sealed mode. The utility model also discloses a battery cell, a battery and electric equipment.