Abstract: A frame attachment assembly includes a hollow element, and a bracket configured to be inserted into the hollow element. The bracket includes an elongated body extending between a first end and a second end, a first plate element positioned at the first end, the first plate element having an aperture configured to receive a first fastener, and a second plate element positioned at the second end, the second plate element having an aperture configured to receive a fastener. The bracket, when inserted into the hollow element, is configured to secure the hollow element between a first and second frame member by securing the first plate element to the first frame member by the first fastener and securing the second plate element to the second frame member by the second fastener.

Abstract: A battery system, which is robust for mobile use and fulfils both the mechanical and thermal and electrical demands on a mobile, portable battery system, which are configured to be used in a flexible manner. The battery system also includes battery modules which in each case have at least one battery cell and one electronic module, at least one string housing, wherein the battery modules are arranged in the at least one string housing, and an external housing, wherein the at least one string housing is arranged in the external housing.