With an electrical power output of more than 5 kW, the aim is for the demonstrator to achieve an electrical efficiency in excess of 50%. SOFC20 is sponsored by the German Federal Ministry of Economics and Technology. The initial test of the planned hot box was completed successfully in March 2012.
For the SOFC20 project, the Fraunhofer Institute for Ceramic Technologies IKTS designed the hot box with eight fuel cell stacks in series. During the test, the stack module achieved a power output of 5.5 kW. Following a further test using simulated natural gas reformate, the stack module will be installed in a specially developed system environment at AVL List GmbH, where it will be tested.
PLANSEE's contribution to this project is the world's largest SOFC interconnects with an integrated protective coating manufactured using powder metallurgy and with dimensions of 130 x 150 mm. These components connect the individual fuel cells and distribute fuel gas and air in the system. With the MK351, PLANSEE has developed an interconnect from chromium (Cr), iron (Fe) and yttrium (Y) - known as a CFY alloy - specially for use in combination with electrolyte supported cells made from fully stabilized zirconia. The coefficient of expansion of this chromium-based interconnect is perfectly matched to that of the electrolyte. Unlike proprietary, protected designs, the MK351 interconnect is available to all potential stack manufacturers.
SOTC stands for solid oxide fuel cell, which is used at operating temperatures of between 650 and 1000°C. In an ESC SOFC (Electrolyte Supported Cell), the electrolyte not only conducts the oxygen ions but also ensures the mechanical stability of the cell. Unlike other types of fuel cell, the SOFC is not only able to convert hydrogen to water with the help of oxygen, but can also convert CO to CO2. This electrochemical reaction results in the generation of predominantly electrical power from the energy contained in the gases.