An electrochemical energy storage element includes an electrode-separator assembly enclosed in a housing that includes a closure assembly. The closure assembly includes a first sheet metal part having a first side, an opposite second side, and an aperture. The closure assembly also includes a second sheet metal part having a contact segment extending on the first side of the first sheet metal part, a fixing segment extending on the second side of the first sheet metal part, and a tubular feedthrough connecting the connecting the contact segment and the fixing segment through the aperture. An electrically insulating seal is disposed between the first sheet metal part and the second sheet metal part. A first part of the fixing segment is formed as a bottom that closes the tubular feedthrough on the second side of the first sheet metal part.