Computational study of the effect of photovoltaic (PV) module parameters on stress development in silicon under static loading

A photovoltaic (PV) module is subjected to numerous cycles of mechanical and thermal loads during its lifetime. These loads can induce normal and shear stresses in different layers of the module. Normal stresses may lead to crack development and propagation in silicon resulting in power loss. Excessive shear stresses may culminate in delamination of different layers. Choosing appropriate materials, module-layout design and layers' dimensions may help in mitigating the stresses that induce premature failure. However, it is both expensive and time consuming to evaluate the most optimum conditions for module reliability experimentally. We have used finite element (FE) computations to determine stress development in the silicon layer while exerting a static pressure load of 5400 Pa on the PV module. This has been done for a range of glass thicknesses. Stress profiles for multiple module-layouts as well as stack designs have been evaluated as well and significant differences in the magnitude and distribution of normal stresses have been found. This has serious implications for crack development in silicon layer and the subsequent power loss. Informed decisions about the overall design of the module to improve reliability can be taken using the results in this study.