The promotion of electric vehicles with an adequate cruising range intensifies the necessity of lightweight constructions – especially in terms of the battery systems. On the one hand side the batteries have to be powerful and robust, on the other hand their operation weight is supposed to be less dominant, as it directly influences the nominal reach of the corresponding automobile. Against this background the industrial production concentrates on battery trays made of different sorts of Aluminum. While the supporting frame is realized by extruded profiles or casted structures, sheet material is used for covers and forged parts together with castings serve for attachments. In order to ideally combine these mixtures of Aluminum variants to one ideal assembly, plenty of joining technologies are used. In this context the present article focuses on welding technologies, as they enable dynamic strength and media tightness at the same time and for a long period. Aside from the conventional arc welding the battery trays are commonly produced by laser and laser-hybrid processes as well as Friction Stir Welding (FSW). While arc and laser welding are fusion processes and melt or even evaporate the workpiece, FSW features a solid-state technology without any molten state of the relevant base materials. The usage of filler material and therewith a manipulation of the chemical composition in the weld seam is typically for fusion technologies, not for solid-state welding. On the other hand the significantly lower working temperature of FSW can generate a grain refinement and preserve the properties of self-hardening alloys. So the variety of welding technologies together with the mixture of Aluminum variants offer a large influence on the resulting characteristics of the processed battery trays. In the presentation the current situation is illustrated and summarized by an outlook towards future applications.