Abstract
Off-grid power generation is considered as an attractive market for fuel cells. For this purpose, a compact SOFC battery hybrid system was developed that operates on commercially available fuels. Due to its progressive thermal packaging, the mobile prototype achieves a net efficiency of 22 % with commercial BoP components. It was possible to reduce the cold start time of the system by direct cathode preheating with burner off-gas. Thus, the system is designed for frequent start-up and cycling capability. In consequence the planar SOFC stack was tested with rapid heating rates up to 20 K/min in furnace and hotbox environment. The degradation caused by system cycling is less than 0.1 % per cycle. Finally, the optimization of stack temperature conditions has improved the lifetime of the SOFC stack significantly.