Finite element modeling and analysis of photovoltaic modules

A Photovoltaic (PV) module consists of layers of different materials constrained together through an encapsulant polymer. During operation, it experiences mechanical and thermal loads due to seasonal and temperature variations, which cause breakage of interconnects owing to fatigue and laminate warpage. This is due to the fact that there is a coefficient of thermal expansion (CTE) mismatch because of the presence of unlike materials within the laminate. Therefore, thermo-mechanical stresses are induced in the module. Glass, being the thickest of all in the module, plays a significant role in the stressing of components. The lifetime of today's PV module is expected to be 25 years and this period corresponds to the guarantee of the manufacturer. Its high reliability will help it to reach grid parity. But the problem is that it is not convenient to wait and assess its durability. Qualification standards such as ASTM E1171-09 are useful in predicting a module's failure. In this work, material of each component of the PV module is characterized and then the implementation of material models is discussed. A Finite-Element (FE) model of 36 cell PV module is developed using 2D layered shell elements in ANSYS. A single temperature cycle of ASTM E1171-09 is simulated after lamination procedure and 24 hour storage at constant temperature. The FE model is validated by simulating an experimental procedure in the literature by determining change of cell gap during the temperature cycle. Finally, parametric studies are performed with respect to lamination thickness.