Enhancing SOFC-Stack Performance by Model-Based Adaptation of Cathode Gas Transport Conditions

Abstract

High performance anode–supported cells (ASC), contacted in a planar stack by metallic interconnectors (MIC), undergo a significant power density reduction. Performance limiting factors originating from the MIC-design were identified by detailed experimental data analysis and via a straightforward FEM simulation. Conclusively, gas diffusion polarisation contributes close to the sum of all ohmic losses to the overall polarization, both controlling stack performance. Based on this knowledge, a multiphysic-FEM-model was developed, considering coupled ohmic, gas diffusion and nonlinear polarization losses in the electrodes and ohmic losses in the electrolyte. Consequential ASC-performance depends over a broad range of operating conditions on i) an optimal MIC-design and ii) a well-chosen cathode thickness increases the overall power output.