High Efficiency CFY-Stack for High Power Applications

Abstract

SOFC modules with a power of 5 to 50 kW are a serious competitor to commercially available combined heat and power plants for decentralized electricity and heat supply with high electrical efficiency. Electrical efficiency and electrical power of a SOFC stack are essential for its profitable operation. The highest power density and electrical efficiency can only be achieved with planar SOFC stacks. Electrolyte supported cells with 10ScSZ electrolytes allow power densities of more than 500 mW/cm². On account of the thermomechanical properties of electrolyte this potential can only be used in stacks with chromium based interconnects (CFY from Plansee SE). High power, robustness and long-term stability are essential for stationary SOFC systems. In order to fulfill these requirements Fraunhofer IKTS in close collaboration with Plansee SE develops a new stack design with larger active area, simple cathode contacting, external cathode manifold and optimized interconnect layer. This paper will give an overview of the current SOFC stack development focused on power output, long-term stability, temperature cycling and reliability of SOFC stack assembling.