Characterization of Electrical Parameters of Cracked Crystalline Silicon Solar Cells in Photovoltaic Modules

In this work we investigate the characteristics of solar cells cracks in photovoltaic (PV) modules for understanding the extent to which the solar cell electrical parameters change due to cell crack degradation. The experimental investigation is performed on two custom nine-cell mini-modules of mono- and multi-crystalline silicon, respectively, where each solar cell in the module has a junction box, allowing individual and module level characterization. Results show that power loss caused by cell cracks is driven primarily by a reduction of the cell’s maximum power point current, in particular B type cracks. C cracks also affect the short circuit current of the cells, whereas cells with combined B and C cracks show the most reduction of the short circuit current. Equivalent circuit diode model curve fitting and analysis of the light or dark I-V curves proved of limited used in analyzing degradation of cracked cells, as the model assumptions break down. However, a comparative analysis of dark and light I-V curves with a Suns-V
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curve was better suited for understanding the evolution of diode parameters on cracked cells for increasing levels of degradation.