Filling and formation control device for battery

The utility model discloses a filling and formation control device for a battery, which comprises an inner piston, an outer piston, a filling hole on the cover plate of a battery shell, a plastic bracket in the battery shell, and a piston packaging device capable of controlling the gas discharge pressure, wherein the inner piston is fixed in the plastic bracket in a disassembled and assembled way, a screw hole matched with the outer piston is formed in the inner piston, the screw hole is mutually aligned with the filling hole, and the outer piston penetrates the filling hole to be connected with the threads in the screw hole of the inner piston to enclose the filling hole. The positive-direction gas pressure in the battery acts on the inner piston to compress the sealing surface of the inner piston, so as to ensure the gas tightness of the filling hole. By controlling the gas discharge pressure during battery formation, the gas pressure in the battery can be reduced, battery expansion can be reduced, simultan