Investigation and Analysis of Chemical Degradation in Metallization and Interconnects using Electroluminescence Imaging in Crystalline Silicon Photovoltaic Modules

Electroluminescence imaging (EL) technique has been widely used for detection and analysis of defects and degradation in crystalline silicon photovoltaic (PV) modules. However, it has not been effectively exploited for identification, analysis and differentiation of multiple chemical degradation products in metallization and interconnects, under moisture intrusive conditions. This paper presents a systematic approach to identify characteristic patterns of chemical degradations using EL imaging technique including oxide formation at fingers in cell edges, and tin migration at finger-cell interface. The present work can be used for differentiation of chemical degradation from other defects, which appear similar in EL images.