Dynamic electrochemical model for SOFC-stacks

A dynamic electrochemical model based on an equivalent circuit model for anode supported cells (ASC) was developed further to the stack plane level. The model parameters were identified from experimental ASC data (iv-curves and EIS) followed by a pre-identification via the distribution of relaxation times (DRT) and a Complex Nonlinear Least Squares fit (CNLS-fit). The dynamic electrochemical stack model allows separating the contributions of (i) ohmic resistance, (ii) gas phase polarisation (anode substrate), (iii) electrochemistry in the anode functional layer and (iv) oxygen reduction reaction (cathode) as a function of operating voltage and fuel gas composition along the gas channel. As a conclusion, the stack impedance and the static and dynamic current density distribution can be simulated on a stack plane level for a broad range of operating conditions.