This study concerns deformation and fracture of solder bonds and adjacent materials in photovoltaic modules. The mismatch in coefficients of thermal expansion between different materials causes internal deformation and stress buildup, leading to structural failure. Numerical finite element analyses are performed, using layered model structures, to quantify deformation and simulate the ductile failure process in solder. Failure propensity and pattern in solder, as well as cracking tendency in silicon, are identified. The mechanical stiffness of the encapsulation material is found to play a critical role.
