Degradation in PV Encapsulant Strength of Attachment: An Interlaboratory Study Towards a Climate-Specific Test

David C. Miller, Eleonora Annigoni, Amal Ballion, Jayesh G. Bokria, Laura S. Bruckman, David M. Burns, Xinxin Chen, Jiangtao Feng, Roger H. French, Sean Fowler, Christian C. Honeker, Michael D. Kempe, Hussam Khonkar, Michael Kohl, Laure Emmanuelle Perret-Aebi, Nancy H. Phillips, Kurt P. Scott, Fanny Sculati-Meillaud, John H. Wohlgemuth

Research output: Contribution to conferencePaperpeer-review

14 Scopus Citations


Reduced strength of attachment of the encapsulant resulting from the outdoor environment, including ultraviolet (UV) radiation, may decrease photovoltaic (PV) module lifetime by enabling widespread corrosion of internal components. To date, few studies exist showing how the adhesion of PV components varies with environmental stress. We have conducted an interlaboratory experiment to provide an understanding that will be used to develop climatic specific module tests. Factors examined in the study included the UV light source (lamp type), temperature, and humidity to be proposed for use in accelerated aging tests. A poly (ethylene-co-vinyl acetate) (EVA) formulation often used in veteran PV installations was studied using a compressive shear test - to quantify the strength of attachment at the EVA/glass interface. Replicate laminated glass/polymer/glass coupon specimens were weathered at 12 institutions using a variety of indoor chambers or field aging. Shear strength, shear strain, and toughness were measured using a mechanical load-frame for the compressive shear test, with subsequent optical imaging and electron microscopy of the separated surfaces.

Original languageAmerican English
Number of pages6
StatePublished - 18 Nov 2016
Event43rd IEEE Photovoltaic Specialists Conference, PVSC 2016 - Portland, United States
Duration: 5 Jun 201610 Jun 2016


Conference43rd IEEE Photovoltaic Specialists Conference, PVSC 2016
Country/TerritoryUnited States

Bibliographical note

See NREL/CP-5J00-65539 for preprint

NREL Publication Number

  • NREL/CP-5J00-67957


  • durability
  • reliability
  • Xenon


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