Examination of a Size-Change Test for Photovoltaic Encapsulation Materials

David C. Miller, Xiaohong Gu, Liang Ji, George Kelly, Nichole Nickel, Paul Norum, Tsuyoshi Shioda, Govindasamy Tamizhmani, John H. Wohlgemuth

Research output: Contribution to conferencePaperpeer-review

1 Scopus Citations


We examine a proposed test standard that can be used to evaluate the maximum representative change in linear dimensions of sheet encapsulation products for photovoltaic modules (resulting from their thermal processing). The proposed protocol is part of a series of material-level tests being developed within Working Group 2 of the Technical Committee 82 of the International Electrotechnical Commission. The characterization tests are being developed to aid module design (by identifying the essential characteristics that should be communicated on a datasheet), quality control (via internal material acceptance and process control), and failure analysis. Discovery and interlaboratory experiments were used to select particular parameters for the size-change test. The choice of a sand substrate and aluminum carrier is explored relative to other options. The temperature uniformity of ?5?C for the substrate was confirmed using thermography. Considerations related to the heating device (hot-plate or oven) are explored. The time duration of 5 minutes was identified from the time-series photographic characterization of material specimens (EVA, ionomer, PVB, TPO, and TPU). The test procedure was revised to account for observed effects of size and edges. The interlaboratory study identified typical size-change characteristics, and also verified the absolute reproducibility of ?5% between laboratories.

Original languageAmerican English
StatePublished - 2012
EventReliability of Photovoltaic Cells, Modules, Components, and Systems V - San Diego, CA, United States
Duration: 13 Aug 201216 Aug 2012


ConferenceReliability of Photovoltaic Cells, Modules, Components, and Systems V
Country/TerritoryUnited States
CitySan Diego, CA

Bibliographical note

See CP-5200-54186 for preprint

NREL Publication Number

  • NREL/CP-5200-55866

Other Report Number

  • Paper No. 84720T


  • Material characteristics
  • Polymer
  • Quality assurance
  • Shrinkage


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