Resistance welding for future hydrogen economy - the comeback of an old welding technology for modern applications

Upscaling hydrogen production through water electrolysis with proton exchange membranes (PEM) has established high interest in several industrial fields to achieve the ambitious goals given by legislative bodies regarding production volumes and cost reductions. One approach is the substitution of sintered bodies with joined multi-layered expanded metal mesh (EMM) composites that are used as porous transport layers in PEM electrolysis. For joining the multi-layered structures, capacitor discharge welding is a favored welding technology, which offers the possibility for automation, while being a highly economic and robust process. But since EMM exhibits anisotropic properties as well as a wide variety of mesh geometries, the design of such multi-layered composites leads to various possibilities for modifying the properties of the composites in terms of flow characteristics and cell efficiency. Simultaneously, these variations also influence the joining process itself. In this paper, different EMM geometries are joined in 90°- and 180°-layer-to-layer orientation in a resistance projection welding process with capacitor discharge welding. While compression tests reveal improved damping characteristics for 90°-orientation, the CFD simulation hints at more pronounced turbulences in fluid flow which are assumed to favor gas bubble accumulation and a cell efficiency decrease. Contrary, for 180°-orientation less flow turbulences and a smaller pressure drop across the cell are revealed.