Framework for Predicting the Photodegradation of Adhesion of Silicone Encapsulants

Journal Article · Thu Dec 13 00:00:00 EST 2018 · Solar Energy Materials and Solar Cells

DOI:https://doi.org/10.1016/j.solmat.2018.11.024· OSTI ID:1489188

Cai, Can ^[1]; Miller, David C. ^[2]; Tappan, Ian A. ^[2]; Dauskardt, Reinhold H. ^[1]

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1. Stanford Univ., CA (United States)
2. National Renewable Energy Lab. (NREL), Golden, CO (United States)

We developed a framework to predict and model the photodegradation of adhesion and cohesion of a silicone encapsulant for concentrator photovoltaic applications. Silicone encapsulant specimens were artificially weathered under narrow band UV filters to determine the effects of individual wavelengths within the UV spectrum on the photodegradation of the cohesion of encapsulant material and its adhesion with adjacent interfaces. The threshold wavelength, signifying the upper bound of the damaging action spectrum for the silicone, was identified from the results. In addition, specimens were artificially weathered with different relative humidities to understand the effects of moisture on the rate of photodegradation. The adhesion energy was measured using a fracture mechanics approach. The complementary delaminated surfaces were characterized to determine the failure pathway and chemistry changes resulting from photodegradation. A previously developed model was modified to account for the effects of damaging wavelengths in the terrestrial solar spectrum and reciprocity law failure due to varying UV intensity during weathering. With these modifications, the model showed good agreement with the behavior of the silicone encapsulant exposed in an outdoor solar concentrator simulating concentrator photovoltaics operating conditions. Similar studies can be adopted to develop models that can have high predictive accuracies based on accelerated aging studies.

• Research Organization: National Renewable Energy Lab. (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S), SunShot Initiative; USDOE
• Grant/Contract Number: AC36-08GO28308; EE0006343; AC36-08-GO28308
• OSTI ID: 1489188
• Alternate ID(s): OSTI ID: 1636900
• Report Number(s): NREL/JA-5K00-73005
• Journal Information: Solar Energy Materials and Solar Cells, Vol. 191, Issue C; ISSN 0927-0248
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
accelerated aging
concentrator photovoltaics
encapsulant
lifetime prediction
photodegradation
silicone