Simulation and Analysis of Thermal Stress and Sintering Warpage of Planar Solid Oxide Fuel Cells

Due to mismatching of thermophysical properties between involved materials, a non-uniform distribution of generated thermal stress may result in a deformation and warpage in the cell sintering steps for SOFC (solid oxide fuel cell). A three-dimensional CFD (computational fluid dynamics) model is developed to study the displacement and thermal stress distribution within the SOFC sintered functional layers. It is found that the thermal stress is concentrated on the interface between the anode and the electrolyte layers; the warpage is larger during the co-sintering of anode and electrolyte layers (i.e., half-cell sintering). A parameter study is also conducted for the thickness variation of the anode, as well as for the four corners being chamfered. Considering effects of microscopic structure evolution on the cell shrinkage, a correlated method is developed to evaluate the thermal expansion coefficients varied with the sintering temperature. It is found that the difference becomes bigger in the correlated thermal expansion coefficients between the YSZ and anode layers, which leads to even larger displacement predictions. The findings and predicted results may be applied for optimization of the material designs and the sintering parameters for SOFC.