Study on the characteristics of elongation at break and tensile strength of photovoltaic insulating backsheets subjected to partial discharge degradation

As widely distributed vast reserves of emerging green energy, solar energy has gained widespread attention in recent years. Photovoltaic (PV) power generation is one of the most scientific ways to use solar energy. In PV systems, polyethylene terephthalate (PET) is the chief material of PV backsheets. It is well known that PV backsheets will encounter various challenges, among which partial discharge (PD) is one of these that cause deterioration in insulating and mechanical properties of PET. It has severely affected the service life of PV backsheets. In this paper, the PD characteristic of PET samples at different PD durations and temperatures was studied through phase-resolved PD patterns. In addition, the change mechanism of mechanical properties including elongation at break and tensile strength of PET after PD in 30, 60, and 120 min at 30 and 55 °C was also studied. It can be found that the insulating and mechanical properties of PET are reduced after PD degradation at different aging durations and temperatures. This study can provide a reference for the performance improvement of PV PET backsheets, which will also help to evaluate the service life of the PV module and PV power generation systems.