Encapsulant Adhesion to Surface Metallization on Photovoltaic Cells

Nicholas Bosco, Jared Tracy, Reinhold Dauskardt

Research output: Contribution to journalArticlepeer-review

28 Scopus Citations

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 ethylene vinyl acetate (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/antireflective (AR) coating (>2900 J/m2) and ∼60% lower than that of the EVA to the surface of cell (2265 J/m2). After only 300 h 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 chemical byproducts at elevated temperature, which in part accounts for the propensity of metalized surfaces to delaminate in the field.

Original languageAmerican English
Article number8030993
Pages (from-to)1635-1639
Number of pages5
JournalIEEE Journal of Photovoltaics
Volume7
Issue number6
DOIs
StatePublished - 2017

Bibliographical note

Publisher Copyright:
© 2017 IEEE.

NREL Publication Number

  • NREL/JA-5J00-70596

Keywords

  • Accelerated aging
  • adhesion
  • delamination
  • metallization
  • photovoltaic modules

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