Three-dimensional simulation to study the influence of foil thickness on residual stress in the bonded compliant seal design of planar solid oxide fuel cell

► The peak residual stresses are located in foil and BNi2. ► The peak residual stresses are increased as the foil thickness increase. ► With the foil thickness increase, residual stresses in the window frame are increased. ► Residual stresses in Ag–CuO metal are decreased with the foil thickness increase. Bonded compliant seal (BCS) design, which uses a thin S-shaped foil to connect the cell and frame by brazing, is a new sealing method for planar solid oxide fuel cell (SOFC). This paper studies the brazed residual stress in BCS design of a planar SOFC by three-dimensional finite element method. The effect of foil thickness on residual stress has been investigated. The results show that the peak residual stresses are located in S-shaped foil and BNi2 filler metal and have exceeded the yield strength. Therefore S-shaped foil and BNi2 filler metal are the most dangerous zone. The foil thickness has a great effect on residual stress. The peak residual stresses in foil and BNi2 are increased with the foil thickness increase. With the foil thickness increase, the residual stresses in window frame are increased, while residual stresses in Ag–CuO filler metal are decreased.