Reliability and Durability Comparison of Different Backsheet for PV Modules

Backsheet is the first barrier to ensure the 25+ reliability and durability of PV modules. To reduce cost, backsheets with different composition and construction have been developed and introduced to PV modules. For the PV module manufacturers, it is a challenge to select a backsheet with low cost that can maintain the current high reliability and durability performance. This work compared the properties of the several backsheets with different composition and construction. To distinguish the different backsheet properties, intensive and long-term weathering tests were performed. The results showed that the backsheet properties had a significant influence on the durability of the material. The ability of the backsheet to withstand extended high humidity exposure is mainly affected by the hydrolysis performance of core layer PET material, and was not affected by the outer layer material. Some backsheets, like PVDF/PET/PVDF and PVF/PET/PE that use a modified PE as inner layer, also showed a high ability to withstand extended UV exposure. PET-based backsheet showed weak withstand UV performance. The PA-based backsheets demonstrated the worst weatherability performance.