Reliability testing of backsheets: Thermal analysis for comparing single and module aged films


By Gernot Oreski, Senior Researcher, Polymer Competence Center Leoben GmbH; Marlene Knausz, Researcher, Polymer Competence Center Leoben GmbH; Gabriele Eder, OFI Austrian Research Institute for Chemistry and Technology; Yuliya Voronko, Researcher, OFI Austrian Research Institute for Chemistry and Technology, Institute of Materials Science and Technology, Vienna University of Technology; Thomas Koch, Senior Scientist, Institute of Materials Science and Technology, Vienna University of Technology; Karl Berger, Energy Department, Austrian Institute of Technology (AIT)

The main objective of this study was to evaluate the suitability of thermal analysis for characterizing the stage of hydrolytic degradation of PV backsheets containing polyethylene terephthalate (PET) as a core layer. Additionally, the ageing behaviour of single backsheets was compared with that of backsheets incorporated within PV modules. Test modules using identical components (glass, encapsulant, solar cells, etc.), varying only in the type of backsheet used, were fabricated and artificially aged (damp heat:85°C / 85% relative humidity storage up to 2000h). The material characteristics of the single backsheets and module-incorporated backsheets before and after artificial ageing were determined by thermal analysis. It was shown that the most significant changes between unaged and aged sheets can be observed in the cooling curve of the differential scanning calorimetry (DSC) runs. For all materials, a significant increase in the crystallization temperature was found. Furthermore, the results revealed no influence of the PV module lamination procedure on the thermal characteristics of the polymeric backsheets. Even after artificial ageing under damp-heat conditions, differences between single and module-incorporated laminated backsheets were negligible. The ageinginduced degradation effects of PET could be detected by DSC for all the aged sheets. It is therefore proposed that the testing of single PET-based backsheets under accelerated ageing conditions may be a practicable way to investigate the applicability of a new backsheet material for use in reliable PV modules.

Published In

In this issue we offer some insights into what the next wave of photovoltaic technologies may look like as that upturn gathers pace. Industry observers have been in broad agreement that the major next-gen PV technology innovations won’t happen straight away. But there’s also little doubt that the search is now on in earnest for the breakthroughs that will come to define the state of the art in the industry in the years to come.

Read Next

Subscribe to Newsletter

Upcoming Events

Solar Media Events
June 4, 2024
London, UK
Upcoming Webinars
June 11, 2024
3:00 PM (BST) / 4:00 PM (CEST)
Solar Media Events
July 2, 2024
Athens, Greece
Solar Media Events
July 9, 2024
Sands Expo and Convention Centre, Singapore