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Multi-Imaging of PV Module Inhomogeneities in 17 kW PV Power Plant and Mutual Correlations
M. Bokalic, K. Brecl, M. Topic
Electroluminescence, Imaging, Multicrystalline Silicon, PV Module, Inhomogeneities
Photovoltaic Modules and BoS Components
Subtopic: PV Module Design, Manufacture, Performance and Reliability
Event: 35th European Photovoltaic Solar Energy Conference and Exhibition
Session: 5CV.3.4
1269 - 1272
ISBN: 3-936338-50-7
Paper DOI: 10.4229/35thEUPVSEC20182018-5CV.3.4
0,00 EUR
Document(s): paper


We have performed a detailed spatial conversion efficiency inhomogeneity inspection of a 17 kW PV power plant using an in-house developed multi-imaging system that comprises visual, UV fluorescence, EL near infrared and EL short infrared spatial imaging methods applied to full-size PV modules. All the images were comparatively analysed using an in-house developed software package. A statistical analysis of detected inhomogeneities and correlations between them is performed on a per-module basis. Several correlations between inhomogeneities were detected. Disconnected areas have high correlation with Cracks, which is obvious since cracks cause them. High correlation is also present between different types of cracks, as well as between different types of Contact finger interruptions, because these inhomogeneities were classified into types based on their intensity. Negative correlation between Bad Edges – Perpendicular and Compression cracks at random positions was not expected, but may provide a clue that Compression cracks are predefined by the cell manufacturing process. A 90% correlation between Compression cracks at random positions and UV – Dots suggests that UV – fluorescence can be used to detected Compression cracks. The correlation between UV – Along Ribbons and Contact finger interruptions may explain that the non-UV-fluorescent cell area along the ribbons is caused by the micro cracks below ribbons, which also cause contact finger interruptions.