Top cover assembly for battery and battery

A top cover assembly for a battery, the battery comprising a housing having an opening and a jelly-roll disposed within the housing, the top cover assembly being for closing the opening, wherein the top cover assembly comprises:

• a top cover, the top cover having at least one mounting hole, the mounting hole extending through the top cover in a thickness direction of the top cover, the top cover having a first recess on a top surface thereof, the first recess being provided around the mounting hole;
• a terminal post, the terminal post penetrating the mounting hole, a first end of the terminal post being limited to a side of the top cover on which a bottom surface thereof is located, a second end of the terminal post being higher than the top surface of the top cover;
• and
• an upper plastic member, the upper plastic member being provided on a side of the top cover on which the top surface is located and surrounding the second end of the terminal post to be connected to the second end of the terminal post, the upper plastic member having a first boss on a bottom surface thereof, the first boss being accommodated in the first recess, the bottom surface of the upper plastic member being located on the top surface of the top cover, wherein:
• a first convex ring is provided at an outer edge of the first recess, and
• the first convex ring is provided around the mounting hole,
• a first concave ring is provided at a position of the first boss of the upper plastic member corresponding to the first convex ring, and
• the first convex ring is embedded in the first concave ring.