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Title: Tearing and reliability of photovoltaic module backsheets

Abstract

We report that the backsheet in photovoltaic modules belongs to an important class of layered materials where the tearing behavior of the individual layers does not necessarily represent the tearing behavior of the entire backsheet. Such characteristic arises from the interaction between the individual layers during the tearing process, where one layer of the backsheet is mechanically constrained by its neighboring layers and the layers may debond from each other. The mechanical constraint and debonding change the amount of energy dissipated during tearing and affect the overall tearing energy. In this article, we exposed a wide selection of backsheets with polymers including ethylene-vinyl acetate (EVA), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), and ethylene tetrafluoroethylene (ETFE) to damp heat (85°C/85%RH) for up to 2000 hours. We report on the effect of damp heat on the tearing energy as a function of damp heat exposure. We developed a model that describes the tearing energy of a layered structure by accounting for the tearing of the individual layers in the backsheet, the effect of mechanical constraint, and the adhesive debonding between the layers. Additionally, we explore the relationship between the microstructural change in the polymers which resulted from the damp heat exposure andmore » the mechanical properties using modulated differential scanning calorimetry (MDSC), small and wide angle X-ray scattering (SAXS and WAXS), and tensile testing.« less

Authors:
 [1]; ORCiD logo [2];  [3]; ORCiD logo [2]; ORCiD logo [1]
  1. Stanford Univ., CA (United States)
  2. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  3. SolarCity, Fremont, CA (United States)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
OSTI Identifier:
1560684
Alternate Identifier(s):
OSTI ID: 1523542
Grant/Contract Number:  
AC02‐76SF00515; ECCS‐1542152
Resource Type:
Accepted Manuscript
Journal Name:
Progress in Photovoltaics
Additional Journal Information:
Journal Volume: 27; Journal Issue: 8; Journal ID: ISSN 1062-7995
Publisher:
Wiley
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; backsheet; damp heat; MDSC; polymer; reliability; small and wide angle X‐ray scattering; tearing; tensile testing

Citation Formats

Yuen, Pak Yan, Moffitt, Stephanie L., Novoa, Fernando D., Schelhas, Laura T., and Dauskardt, Reinhold H. Tearing and reliability of photovoltaic module backsheets. United States: N. p., 2019. Web. doi:10.1002/pip.3144.
Yuen, Pak Yan, Moffitt, Stephanie L., Novoa, Fernando D., Schelhas, Laura T., & Dauskardt, Reinhold H. Tearing and reliability of photovoltaic module backsheets. United States. doi:10.1002/pip.3144.
Yuen, Pak Yan, Moffitt, Stephanie L., Novoa, Fernando D., Schelhas, Laura T., and Dauskardt, Reinhold H. Wed . "Tearing and reliability of photovoltaic module backsheets". United States. doi:10.1002/pip.3144.
@article{osti_1560684,
title = {Tearing and reliability of photovoltaic module backsheets},
author = {Yuen, Pak Yan and Moffitt, Stephanie L. and Novoa, Fernando D. and Schelhas, Laura T. and Dauskardt, Reinhold H.},
abstractNote = {We report that the backsheet in photovoltaic modules belongs to an important class of layered materials where the tearing behavior of the individual layers does not necessarily represent the tearing behavior of the entire backsheet. Such characteristic arises from the interaction between the individual layers during the tearing process, where one layer of the backsheet is mechanically constrained by its neighboring layers and the layers may debond from each other. The mechanical constraint and debonding change the amount of energy dissipated during tearing and affect the overall tearing energy. In this article, we exposed a wide selection of backsheets with polymers including ethylene-vinyl acetate (EVA), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), and ethylene tetrafluoroethylene (ETFE) to damp heat (85°C/85%RH) for up to 2000 hours. We report on the effect of damp heat on the tearing energy as a function of damp heat exposure. We developed a model that describes the tearing energy of a layered structure by accounting for the tearing of the individual layers in the backsheet, the effect of mechanical constraint, and the adhesive debonding between the layers. Additionally, we explore the relationship between the microstructural change in the polymers which resulted from the damp heat exposure and the mechanical properties using modulated differential scanning calorimetry (MDSC), small and wide angle X-ray scattering (SAXS and WAXS), and tensile testing.},
doi = {10.1002/pip.3144},
journal = {Progress in Photovoltaics},
number = 8,
volume = 27,
place = {United States},
year = {2019},
month = {5}
}

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