Mechanical reliabilities of solid oxide fuel cells (SOFCs) have been evaluated on the basis of physicochemical and mechanical properties of the constituent materials at elevated temper
atures. Mechanical properties at elevated temperatures under controlled atmospheres were measured by a resonance method and small-punch or four point bending tests. Oxygen potential profile and mechanical stress distribution in a cell were evaluated by a finite element method considering the microstructures of the electrode layers using a homogenization technique. Ionic/electronic mixed conductivity of the materials as well as oxygen nonstoichiometry were included in the calculation so that the oxygen potential profile inside the solid phases and then stress distribution were evaluated under steady state and transient conditions. Experimental techniques to verify the results of the simulations, e.g. in-situ Raman microscopy, cell deformation analysis, or acoustic emission measurements were developed depending on the design of the cell stack.
