Liquid injection part structure, battery cover plate and battery

The utility model relates to the field of lithium battery manufacturing, and discloses a liquid injection part structure, a battery cover plate and a battery, the liquid injection part structure comprises a liquid injection part main body, a sealing gasket and a hole plug, the liquid injection part main body is provided with a liquid injection hole penetrating from top to bottom, the liquid injection hole comprises a first through hole located at the upper part and a second through hole located at the lower part, the second through hole is coaxial with the first through hole, the diameter of the second through hole is smaller than that of the first through hole, the hole plug is detachably arranged in the first through hole and matched with the first through hole, the sealing gasket is arranged on a platform where the first through hole and the second through hole are connected, the sealing gasket is arranged below the hole plug, and the sealing gasket is arranged below the hole plug. And the upper end of the