Top cover assembly of secondary battery and secondary battery

The utility model relates to a top cover assembly of a secondary battery and the secondary battery, and the top cover assembly comprises a top cover plate which is provided with a first pole via hole penetrating along the thickness direction, and the upper surface of the top cover plate is provided with a penetrating welding groove surrounding the first pole via hole at the outer side of the first pole via hole; a pole; the bracket is matched with the pole post, and the pole post is embedded in the bracket; the pole cap is arranged on the outer side of the pole column in a surrounding mode and connected with the pole column and the support, the edge of the lower end of the support extends to form a welding part which is exposed out of the pole cap and matched with the penetrating welding groove, and the welding part is arranged in the penetrating welding groove and welded to the bottom face of the penetrating welding groove in a penetrating mode. The secondary battery comprises the top cover assembly. By arra