Solid Oxide Fuel Cell, Stack and System Development Status at Forschungszentrum Jülich

Abstract

Based on more than 20 years SOFC scientific development, JÜLICH is still continuously improving its technology. Utilizing the proprietary cell manufacturing technology of warm pressing of the anode substrate cells of the dimension 20x20 cm² have been manufactured and tested in various stack sizes with power outputs of up to 5 kW, of which four were operated in a 20 kW system. It was demonstrated in a 1 kW stack that cells of this size can also be successfully operated using tape casted substrates. In parallel to the cell development the stack design was improved aiming at enhanced thermo-mechanical robustness. Thereby a stack in the kW range could be cycled successfully 100 times between 200 and 700°C. To be able to integrate also cells from other manufacturers the design was shifted to a picture frame layout, incorporating currently four 10x10 cm² cells in one layer, a larger number of cells is still optional. First successfully operated stacks showed a comparable performance to short stacks with one 10x10 cm² cell. The 20 kW system set into operation in 2012 was operated for about 7000 h in total proofing thereby the suitability of the module and system concept developed in JÜLICH. As special highlights, the long-term tests with short stacks have now reached under continuous operation at 700 °C and 0.5 Acm-² times of 63,000 h (degradation 0.7%/kh, 0.3%/kh in the last 25,000h) and 33,500 h (degradation 0.3%/kh), respectively.