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 significant reliability issues 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 non-critical, 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/m 2 ), followed by recovery after humidity freeze-testing, which may influence outdoor performance and the outcomes of certification tests (IEC61730-2, Sequence B). The results highlight the areas of need for more targeted testing and technological refinement.