The top cover structure of the power battery includes a cap plate, a cathode column, a conducting piece and a reversing piece, the conducting piece is electrically connected with the cathode column, the cathode column is insulatedly assembled with the cap plate; the reversing piece includes a welding part, a embossment with a solid core structure and a joint part arranged between the welding part and the embossment, the embossment is arranged at the center of the joint part, the welding part is arranged on the outer margin of the joint part; the welding part is electrically connected with the cap plate, the embossment does not contact the conducting piece, when the pressure inside the power battery increases, the reversing piece receives the pressure inside the power battery, and moves upwards, so that the embossment is electrically connected to the conducting piece.