Abstract
Delamination of encapsulant materials from PV cell surfaces often appears to originate at regions with metallization. Using a fracture mechanics based metrology, the adhesion of EVA encapsulant to screen printed silver metallization was evaluated. At room temperature, the fracture energy, Gc [J/m2], of the EVA/silver interface (952 J/m2) was ~70% lower than that of the EVA/AR coating (>2900 J/m2) and ~60% lower than that of the EVA to the surface of cell (2265 J/m2). After only 300 hours of damp heat aging, the adhesion energy of the silver interface dropped to and plateaued at ~50-60 J/m2, while that of the EVA/AR coating and EVA/cell remained mostly unchanged. Elemental surface analysis showed that the EVA separates from the silver in a purely adhesive manner, indicating that bonds at the interface were likely displaced in the presence of humidity and elevated temperature, and may explain the propensity for delamination to occur at metallized surfaces in the field.
Original language | American English |
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Number of pages | 5 |
State | Published - 2017 |
Event | 2017 IEEE 44th Photovoltaic Specialists Conference (PVSC) - Washington, D.C. Duration: 25 Jun 2017 → 30 Jun 2017 |
Conference
Conference | 2017 IEEE 44th Photovoltaic Specialists Conference (PVSC) |
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City | Washington, D.C. |
Period | 25/06/17 → 30/06/17 |
Bibliographical note
See NREL/CP-5K00-74000 for paper as published in IEEE proceedingsNREL Publication Number
- NREL/CP-5J00-68601
Keywords
- adhesion
- encapsulant
- EVA
- metallization
- PV module reliability