The section Electrochemical Energy Technology of the DLR Institute of Engineering Thermodynamics, a team of about 60 persons, develops efficient electrochemical storage and conversion devices, namely electrolysers, fuel cells, and advanced batteries. These technologies are becoming more important in future energy systems due to the transformation of the energy sector in Germany. Our activities range from materials development, cell design, stack development, manufacturing and advanced diagnostics up to system optimization. For specific innovative applications we develop demonstrators and prototypes. Scientific and technical challenges for electrochemical energy technology include finding solutions to conflicting goals of efficiency, durability, safety, reliability and cost reduction.