SECONDARY BATTERY AND TOP COVER ASSEMBLY THEREOF

The present disclosure provides a top cover assembly of a secondary battery. The top cover assembly includes: a top cover plate and a gas exhaust valve mounted in the top cover plate. The gas exhaust valve includes a valve body, a valve sleeve and a valve cover. The valve body includes a valve part, and the valve part is provided with a gas exhaust hole that communicates with an interior of the secondary battery. The valve cover seals and is connected to the valve body to form an accommodation space. The valve sleeve is located in the accommodation space, and the valve sleeve covers the valve part. A gas exhaust passage is disposed between the valve sleeve and the valve part, the valve cover is provided with a venting hole that communicates with outside, and the gas exhaust passage communicates with the gas exhaust hole and the venting hole.