BACKFLIP: A Comparison of Emerging Non-Fluoropolymer-Based, Co-Extruded PV Backsheets to Industry-Benchmark Technologies

Conference · Tue Feb 08 04:00:00 EST 2022

OSTI ID:1845086

Al Hasan, Naila M.; Arnold, Rachael L.; King, Bruce; Miller, David C.; Newkirk, Jimmy M.; Rago, Emily; Schelhas, Laura T.; Sinha, Archana; Terwilliger, Kent; Thuis, Michael; Ulicna, Sona

As the photovoltaic (PV) industry is rapidly expanding around the world, there has been an increasing interest in extending the lifespan of PV modules. Concern has also emerged regarding the recyclability of modules and their component materials, including fluoropolymer-based backsheets. Laminated polyethylene-terephthalate (PET) core backsheets have traditionally been used in the PV industry, but new, co-extruded polyolefin (PO) backsheets show promise as an improved alternative. Mini-module and coupon samples of seven different backsheets (made of layers including contemporary PET and fluoropolymers, novel PO, and polyamide (PA) materials) were run through hygrometric- or UV photolytic-accelerated aging to identify and better understand each material's degradation modes and the backsheets' field reliability. In addition to the artificial aging, the natural weathering methods used in this study are described. The comprehensive set of chemical, mechanical, and structural characterizations at intermittent read points in this study is presented, including: visual appearance and color; gloss; mechanical tensile testing; I-V performance; electroluminescence (EL) imaging; dielectric breakdown; FTIR-chemical structure; X-ray-polymer structure (WAXS); and DSC-crystalline content. After 4000 h of aging, a strong correlation occurs between initial physical characteristics (mechanical tensile test) and operating performance (EL and I-V characteristics). This presentation focuses on gloss, FTIR, and breakdown voltage measurements. Results for MiMo power, grayness from EL imaging, optical micrscopy, and specimen morphology (on extraction when cut from MiMos) is also presented.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S), Durable Modules Consortium (DuraMAT)
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 1845086
• Report Number(s): NREL/PR-5K00-81880; MainId:82653; UUID:b514469a-6e89-45be-b06f-cad1731f5300; MainAdminID:63835
• Country of Publication: United States
• Language: English

Related Subjects

DuraMAT
IEC TS 62788-7-2
PET
SOLAR ENERGY
UV weathering
backsheet
damp heat testing
durability
polyolefin