MICRO LEVEL TWO DIMENSIONAL STRESS AND THERMAL ANALYSIS ANODE/ELECTROLYTE INTERFACE OF A SOLID OXIDE FUEL CELL

Abstract

The delamination and degradation of solid oxide fuel cells (SOFCs) electrode/electrolyte interface is estimated by calculating the stresses generated within the different layers of the cell. The stresses developed in a SOFC are usually assumed to be homogenous through a cross section in the mathematical models at macroscopic scales. However, during the operating of these composite materials the real stresses on the multiphase porous layers might be very different than those at macro-scale. Therefore micro-level modeling is needed for an accurate estimation of the real stresses and the performance of SOFC. This study combines the microstructural characterization of a porous solid oxide fuel cell anode/electrolyte with two dimensional mechanical and electrochemical ana yses to investigate the stress and the overpotential. The microstructure is determined by using focused ion beam (FIB) tomography and the resulting microstructures are used to generate a solid mesh of two dimensional triangular elements. COMSOL Multiphysics package is employed to calculate the principal stress and Maxwell Stefan Diffusion. The stress field is calculated from room temperature to operating temperature while the overpotential is calculated at operating temperature.