Effects of non-planar interface and electrode parameters on the residual stress of solid oxide fuel cell

The thermomechanical response of solid oxide fuel cell will endanger its structural reliability. In this study, the effects of non-planar interface and electrode parameters are investigated by building a cosine anode-electrolyte interface with amplitude A and wavelength λ. Results show that the planar interface model cannot completely reflect the stress state of solid oxide fuel cells. Non-planar interface can stimulate high normal stress S_n and shear stress S_t at the interface, but these stresses are zero at the planar interface. Cosine interface causes approximately cosinoidal S_n and sinusoidal S_t. The bigger the ratio of amplitude to wavelength A/λ is, the more serious the S_n fluctuates. Electrode parameter analysis shows that increasing initial porosity of oxidized anode can reduce the maximum S_n but increases the maximum S_t and the cell deflection. Parameter study show that initial porosity between 0.15 and 0.25 is suitable. The effect of anode thickness on the maximum S_n and S_t is weak, while the electrolyte thickness has a relatively strong effect when the electrolyte thickness is less than 12 μm. A NiO volume fraction between 0.52 to 0.58 is recommended to avoid overlarge S_n, S_t, and deflection.