Forensic analysis of Si-based PV module micro-cracking due to standard IEC thermal and mechanical testing procedures

摘要

Micro-cracking analysis of Si-based photovoltaic (PV) modules and its effect on the module performance has been under study since a few years but only from a theoretical point of view. Currently there is not a well stablished procedure to evaluate the micro-cracking in order to prevent it and the electrical losses associated when aging and mechanical stress caused produced under normal working conditions and maintenance. In this work we show a forensic analysis of real PV modules uninstalled from a multi-MW PV plant and tested in a certified IEC lab for a micro-cracking analysis using camera based electroluminescent (EL) imaging analysis and solar simulator pre- and post-climate chamber. The results show that the thermal cycles applied to the PV modules produce almost no new micro-cracks but predispose the PV modules to cracking in subsequent mechanical testing. The results are useful for planning the addition of a new film to reinforce the PV module and, consequently, diminish the evolution of these micro-cracks.