A validated multi-scale model of a SOFC stack at elevated pressure

Abstract

This paper presents a multi-scale model of a solid oxide fuel cell (SOFC) stack consisting of five anode-supported cells. A two-dimensional isothermal elementary kinetic model is used to calculate the performance of single cells. Several of these models are thermally coupled to form the stack model. Simulations can be carried out at steady-state as well as dynamic operation. The model is validated over a wide range of operating conditions including variation of temperature, gas composition (both on anode and cathode side), and pressure. Validation is carried out using polarization curves and impedance spectra. The model is then used to explain the pressure-induced performance increase measured at constant fuel utilization of 40%. Results show that activation and concentration overpotentials are reduced with increasing pressure.