EXPLOSION-PROOF SHEET, TOP COVER ASSEMBLY OF SECONDARY BATTERY, AND SECONDARY BATTERY

This application relates to the technical field of batteries, in particular to an explosion-proof sheet, a top cover assembly of a secondary battery, and a secondary battery. The explosion-proof sheet includes a pressure release portion arranged oppositely with the explosion-proof hole, a fixing portion surrounding the pressure release portion and connected to the top cover, a connecting portion located between the pressure release portion and the fixing portion and configured to connect the pressure release portion and the fixing portion. A thickness of a part of the connecting portion is greater than a thickness of the remaining part of the connecting portion. The explosion-proof sheet may be prevented from departing from the top cover integrally during pressure release, thereby the usage safety of the battery may be improved.