The Jülich SOFC modelling group has been performing 3D coupled multiphysics modelling of SOFCs, auxiliary components, as well as whole fuel cell systems since five years. Currently, emphasis has been given to the thermomechanical robust design and process optimisation of full-scale fuel cell stacks and whole fuel cell systems, including all auxiliary components. Particular attention is given to improve the understanding of the steady and transient processes, effecting the robustness and life-time duration of the components that directly influence the performance. Coupled CFD/FEM is used to mimic the thermofluid flow, electrochemical and chemical reactions, as well as thermo- mechanics.