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Characterization of a Silicon Based Thermoplastic Elastomer for PV Encapsulation
G. Oreski, G. Wallner, P. Randel
Encapsulation, Polymer Film, Aging Behaviour
Components for PV Systems
Subtopic: PV Modules
Event: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain
Session: 4AV.3.48
2922 - 2924
ISBN: 3-936338-24-8
Paper DOI: 10.4229/23rdEUPVSEC2008-4AV.3.48
0,00 EUR
Document(s): paper


Ethylene vinyl acetate copolymer (EVA) is the dominant material for PV encapsulation, especially for modules with crystalline silicon solar cells. Due to some disadvantages such as time consuming curing in the module lamination process or the amount of different additives used, research work focuses on the identification and qualification of new materials for solar cell encapsulation. One candidate material for PV encapsulation are siliconbased thermoplastic elastomers (TPSE), developed by Wacker Chemie AG (D), which combines thermoplastic processability with outstanding silicon properties. Eight TPSE formulations with different chemical composition, molar mass and UV absorber content were investigated and exposed to temperature and moisture (damp heat test). To describe chemical degradation and physical aging, reference and aged materials were characterized by infrared spectroscopy in attenuated total reflection mode (ATR), by UV/VIS/NIR spectroscopy, by dynamic mechanical analysis (DMA) and by tensile tests. All investigated materials are highly transparent in the solar range, showing transmittance values above 0.9. Tensile testing and DMA revealed high flexibility over a broad temperature range (- 50 to 100°C) with elastic modulus values between 5 and 10MPa and strain-at-break values about 600%. The UV stability of TPSE is quite good. Damp heat results depend highly on chemical modifications of the polymer chain.