Reliability of Commercial TOPCon PV Modules - An Extensive Comparative Study

Tunnel oxide passivated contact (TOPCon) is poised to emerge as the predominant technology in photovoltaic (PV) cells, yet accelerated aging tests point towards significant reliability issues that remain unresolved. This study conducts a comparative analysis of 20 TOPCon PV module types, utilizing a range of electrical characterization and accelerated aging assessments. This investigation provides a detailed evaluation of the electrical performance, resulting in an energy rating of the modules, establishing a benchmark for cutting-edge TOPCon technology. While some failure modes, such as LeTID, appear to be noncritical, the findings confirm previously identified degradation pathways in TOPCon modules due to moisture penetration. During UV exposure, a novel degradation pattern was observed during the indoor tests, showing severe losses (up to -12% after 120 kWh/m2), followed by recovery after humidity freeze testing, which may influence outdoor performance and the outcomes of certification tests (IEC 61730-2, Sequence B). The results highlight the areas of need for more targeted testing and technological refinement.