TOP COVER ASSEMBLY AND SECONDARY BATTERY

The present application relates to a top cover assembly and a secondary battery. The top cover assembly includes: a top cover plate including a lead-out hole and an inside surface forming the lead-out hole; an electrode terminal including a cylindrical portion penetrating the lead-out hole and an annular flange, the annular flange extending beyond the inside surface along the lead-out hole; a sealing ring including a barrel portion and a ring portion, surrounding the cylindrical portion by the barrel portion, the barrel portion seals the inside surface and the cylindrical portion. The ring portion includes a first ring body and a second ring body distributed in the radial direction. The first ring body is connected to the barrel portion; the annular flange is connected to the top cover plate through the first ring body in a sealing manner, and the second ring body does not extend beyond the annular flange; an insulating member including a connecting portion and an extension portion, along the axial direction of the lead-out hole, a projection of the connecting portion overlaps with a projection of the second ring body, and the connecting portion seals the second ring body; a portion of the insulating member beyond the second ring body forms the extension portion, and in the radial direction, the extension portion extends beyond the annular flange.