Prediction of crack propagation paths in the unit cell of SOFC stacks

Planar Solid Oxide Fuel Cells (SOFC) stacks are multi-material layered systems with different thermo-mechanical properties. Due to their severe thermal loading, these layers have to meet high demands to preserve their mechanical integrity without any cracks initiation and propagation. In this paper, cracks propagation in a typical unit cell of the stack which consists of positive electrode–electrolyte–negative electrode (PEN) is modeled. Based on the mechanical properties of each layer and their interfaces, an energy criterion as a function of crack length is used for the prediction of possible crack extensions in the PEN. An analysis of the competition between crack deflections in the interfaces and crack penetration in layers is presented.