SECONDARY BATTERY

A secondary battery is disclosed, including: an electrode unit, including an electrode body and a tab extending from the electrode body, where the tab includes a first part and a second part that are spaced apart along a height direction of the secondary battery; and a top cover assembly, disposed on one side of the electrode body toward the tab, where the top cover assembly includes a top cover body and a hold-down beam, and a positioning bulge is disposed on a first surface of the top cover body toward the electrode unit, a positioning chute is disposed on the positioning bulge, and the hold-down beam is located between the first part and the second part, and is detachably disposed in the positioning chute. This application improves safety performance of the secondary battery effectively.