Simulation of cracking of electrode assembly in planar solid oxide fuel cell

Cracking characteristics of the positive electrode-electrolytenegative electrode (PEN) assembly under thermal stresses in a planar solid oxide fuel cell (SOFC) stack are studied, using finite element analysis (FEA). A 3-D FEA model is constructed for a multiple-cell stack to perform thermal stress analysis at both steady operation and shutdown stages. The stress intensity factors for various combinations of surface crack shape (semicircular and semi-elliptical) and size (1 μm, 10 μm, and 100 μm) at the highly stressed regions in the PEN are calculated at both room temperature and steady stage. Simulation results indicate the stress intensity factor is increased with crack size for semicircular surface cracks. A deep, semi-elliptical surface crack tends to grow wider, while a shallow one tends to grow deeper.