  A multi-physics and multi-scale computational approach is proposed in the
present work to study the evolution of microcracking in polycrystalline Silicon
(Si) solar cells composing photovoltaic (PV) modules. Coupling between the
elastic and the electric fields is provided according to an equivalent circuit
model for the PV module where the electrically inactive area is determined from
the analysis of the microcrack pattern. The structural scale of the PV
laminate(the macro-model) is coupled to the scale of the polycrystals (the
micro-model) using a multiscale nonlinear finite element approach where the
macro-scale displacements of the Si cell borders are used as boundary
conditions for the micro-model. Intergranular cracking in the Si cell is
simulated using a nonlinear fracture mechanics cohesive zone model (CZM). A
case-study shows the potentiality of the method, in particular as regards the
analysis of the microcrack orientation and distribution, as well as of the
effect of cracking on the electric characteristics of the PV module.
