Characterisation of Potential-Induced Degradation Shunting in c-Si PV Modules Using Electroluminescence and Infrared Imaging

Potential-induced degradation shunting (PID-s) is a major degradation mechanism that significantly impacts the long-term performance and reliability of crystalline silicon (c-Si) photovoltaic (PV) modules. For regular maintenance and monitoring, the investigation and characterization of PID-s are essential. Techniques such as current-voltage (I-V) characteristics, electroluminescence (EL) imaging, and infrared thermography (IRT) are commonly used for this purpose. However, implementing I-V characterization on large-scale utility PV fields is not feasible due to practical limitations. Therefore, EL imaging and IRT emerge as more suitable methods for PID-s characterization. Yet, PID-s manifests with varying severity and nature, and no single technique can comprehensively capture all aspects. EL imaging has limitations in characterizing severely affected PID-s cells, whereas IRT can detect thermal signatures even in cases where EL imaging fails. On the other hand, IRT primarily captures the effect (heat generation), not the root cause. It does not reveal the nature of PID-s, such as ohmic and nonohmic which depends sodium ion concentration diffused in p-n junction. EL imaging, however, can detect such phenomena, making it more effective in evaluating the underlying nature of PID-s. Therefore, this work presents the combined application of EL imaging and IRT for a comprehensive analysis and characterization of PID-s. The integration of both techniques offers complementary strengths, enhances PID-s diagnosis, and improves the reliability forecasting of PV systems.