Investigation of fatigue crack propagation in photovoltaic modules under dynamic cyclic loading

Microcracks in silicon cells induced by environmental loads would significantly degrade the long-term power output and reliability of photovoltaic (PV) modules. Previous studies concern the development of microcracks under static loads but limited attention have been paid to the fatigue crack propagation under dynamic cyclic loading. In this study, a three-dimensional numerical model based on the extended finite element method (XFEM) and Paris’ law was built to investigate the crack propagation in silicon cells under cyclic loading. The numerical model was validated against published experimental data to ensure its accuracy. An optimized mounting location was obtained to minimize the crack area in silicon cells. With the optimized mounting location, the fatigue crack behavior in silicon cell with different initial microcracks under dynamic cyclic loads with different amplitude, frequency, and waveforms were studied. It is found that the load amplitude significantly influences the propagation of crack. The crack in silicon cells increase progressively with the increase of loading cycles. The waveform of cyclic loading plays a key role in determining the final state of fatigue cracks. Unidirectional pressure cycling poses a greater fatigue risk than bidirectional pressure cycling. These findings would be helpful for the design and maintenance of PV systems.