Modeling of solid oxide fuel cells with optimized interconnect designs

A 3D model is developed to investigate solid oxide fuel cells (SOFCs) contacting with optimized interconnect designs and the results indicate that the current density and thermal stress are closely related to both the shape of tip in interconnects and the depth of it in the cathode. The interconnect with triangular rips can yield the best electrochemical performance compared to those with tips of rectangle and trapezium, and the current densities increase with the depth of tips in cathodes, except the trapezoidal ribs, which shows a concaving change with the depth. The 1st principle stress reaches around 21.9 MPa and 16.6 MPa at the interfaces of electrodes and electrolytes, but it rises to 60 MPa and 18 MPa for the rectangular tips at the air and fuel inlets, respectively, which sharply decreases to nearly 25 MPa and 10 MPa with the depth in cathodes approaching 5 μm. The maximum shear stresses are found to reach 34.4 MPa and 32.1 MPa at the two interfaces, and the triangular tips will induce the most intensive stresses at electrolyte-cathode interface. The resulting conclusions are beneficial to optimize interconnect design to improve the efficiency of current collection and also reduce the risk of generation of remarkable thermal stresses.