Title:	Crack Propensity of PV Backsheets – Comparison of Laminated and Co-extruded Backsheets
Author(s):	G. Oreski, C. Barretta, A. Macher, G.C. Eder, L. Neumaier, M. Feichtner, M. Aarnio-Winterhof
Keywords:	Encapsulation, Reliability
Topic:	Photovoltaic Modules and BoS Components
Subtopic:	Materials for PV Modules, Durability, Reliability and Accelerated Testing Methods
Event:	8th World Conference on Photovoltaic Energy Conversion
Session:	3DO.17.1
ISBN:	3-936338-86-8
Price:	0,00 EUR
Document(s):	presentation

Abstract/Summary:

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Co-extruded backsheets based on polypropylene (PP) are an interesting alternative to laminated backsheets containing polyester films (PET). Backsheet cracking has become a frequent failure mode in the last years, causing not only safety issues but on the long term also reducing the lifetime of PV modules. In this work the crack susceptibility of different backsheets was investigated using solder bump coupon specimens. The solder bump coupons were exposed to test sequence of exposure to UV light followed by thermal cycles. Overall, the PP as well as the fluoropolymer backsheets showed excellent stability and no susceptibility to material embrittlement or cracking. By comparison, the PA as well as the PET based backsheets showed next to significant discoloration also strong cracking after a few test cycles. Overall, the study confirms that co-extruded PP backsheets show great potential to be a valid replacement of standard PET based backsheets in PV modules.