Comparison of Commercial TOPCon PV Modules in Accelerated Aging Tests

TOPCon is set to become the new mainstream cell technology despite considerable reliability concerns. This work compares commercially available full-scale TOPCon PV module types from 5 different manufacturers in a variety of electrical characterization, accelerated aging tests and (for some selected types) outdoor exposure. This case study represents a selection process of PV modules for larger PV installations. Therefore, the work features an in-depth comparison of the electrical performance (Energy Rating) that can serve as a reference for state-of-the-art TOPCon modules. The preliminary aging results confirm previously reported degradation mechanisms of the TOPCon technology due to humidity and UV stresses. Where possible, connections to the used bill of materials, with focus on the encapsulant, are drawn. In the case of UV aging, a new pattern of strong degradation (up to 12 % after 60 kWh/m²) and subsequent recovery after humidity freeze-test is presented, which could have implications on the results of certification tests (IEC61730-2, Sequence B). The outdoor exposure is used to evaluate the development of this failure pattern under realistic outdoor conditions, for different operation conditions. Finally, areas of demand for more focused testing and technological development are highlighted.