Investigating the Crosslinking, Degradation, and Adhesion Behavior of Photovoltaic Encapsulants Under Thermal Accelerated Aging

Liu, Kuan; Miller, David C.; Bosco, Nick; Newkirk, Jimmy M.; Sakamoto, Tomoko; Dauskardt, Reinhold H.

doi:10.1109/JPHOTOV.2024.3496512

Investigating the Crosslinking, Degradation, and Adhesion Behavior of Photovoltaic Encapsulants Under Thermal Accelerated Aging

Journal Article · Sun Dec 15 23:00:00 EST 2024 · IEEE Journal of Photovoltaics

DOI:https://doi.org/10.1109/JPHOTOV.2024.3496512· OSTI ID:2500784

Liu, Kuan; ; ; Newkirk, Jimmy M.; Sakamoto, Tomoko; Dauskardt, Reinhold H.

Degradation of photovoltaic (PV) module encapsulant characteristics that lead to mechanical embrittlement and delamination remains a cause of failure in solar installations. A multiscale reliability model connecting the encapsulant mechanical and fracture properties to the degraded molecular structure and interfacial bonding to adjacent solar cell and glass substrates was previously published. The model, developed primarily for poly(ethylene-co-vinyl acetate) acetate (EVA) encapsulants, remains to be experimentally validated. Determining the degradation and crosslinking kinetics of alternative encapsulants, such as polyolefin elastomer (POE) and EVA/POE/EVA composites (EPE), can generalize the model. In this work, we subject fully cured EVA, POE, and EPE encapsulants to accelerated thermal aging to determine how high temperatures impact reaction kinetics. An increase in gel content (crosslinking) and decrease in crystallinity of the encapsulants under hot-aerobic (90 degrees C, 22% RH) and hot-anaerobic (90 degrees C, sealed in N 2 air) aging were observed, even in the absence of UV and crosslinking initiators. Fourier transform infrared spectroscopy (FTIR)-attenuated total reflectance analysis showed insignificant encapsulant degradation, demonstrating the critical role of UV and moisture in accelerating degradation. Adhesion testing performed on coupon-level specimens (cell/encapsulant/glass laminates) showed decreases in adhesion energy, Gc , from 5000 h of hot-dry (90 degrees C, ~1% RH) and hot-humid (90 degrees C, 60% RH) aging. POE coupons demonstrated the best stability, followed by EPE then EVA. For EVA and POE, hot-humid aged coupons experienced a larger decrease in Gc due to enhanced hydrolytic degradation. Hot-dry aging condition demonstrated that thermal degradation of the interface could be significant even if the encapsulant experiences negligible degradation in the absence of UV and elevated humidity.

Research Organization:: National Renewable Energy Laboratory (NREL), Golden, CO (United States)

Sponsoring Organization:: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office; National Science Foundation (NSF)

DOE Contract Number:: AC36-08GO28308

OSTI ID:: 2500784

Report Number(s):: NREL/JA-5K00-92085; MainId:93863; UUID:462659ee-a8c3-40b6-ad33-390d1511e1ae; MainAdminId:74285

Journal Information:: IEEE Journal of Photovoltaics, Journal Name: IEEE Journal of Photovoltaics Journal Issue: 2 Vol. 15

Country of Publication:: United States

Language:: English

References (30)

Effect of UV aging on degradation of Ethylene-vinyl Acetate (EVA) as encapsulant in photovoltaic (PV) modules Badiee, Amir; Wildman, Ricky; Ashcroft, Ian SPIE Solar Energy + Technology, SPIE Proceedings https://doi.org/10.1117/12.2062007	conference	October 2014
Review of degradation and failure phenomena in photovoltaic modules Aghaei, M.; Fairbrother, A.; Gok, A. Renewable and Sustainable Energy Reviews, Vol. 159 https://doi.org/10.1016/j.rser.2022.112160	journal	May 2022
Predicting encapsulant delamination in photovoltaic modules bridging photochemical reaction kinetics and fracture mechanics Liu, Kuan; Thornton, Patrick; D'hooge, Dagmar R. Progress in Photovoltaics: Research and Applications, Vol. 32, Issue 5 https://doi.org/10.1002/pip.3771	journal	December 2023
The thermal degradation of poly(vinyl acetate) and poly(ethylene-co-vinyl acetate), Part I: Experimental study of the degradation mechanism Rimez, B.; Rahier, H.; Van Assche, G. Polymer Degradation and Stability, Vol. 93, Issue 4 https://doi.org/10.1016/j.polymdegradstab.2008.01.010	journal	April 2008
Evaluation of high-temperature exposure of photovoltaic modules Kurtz, Sarah; Whitfield, Kent; TamizhMani, G. Progress in Photovoltaics: Research and Applications, Vol. 19, Issue 8 https://doi.org/10.1002/pip.1103	journal	March 2011
Viscoelastic Material Characterization and Modeling of Photovoltaic Module Packaging Materials for Direct Finite-Element Method Input Bosco, Nick; Springer, Martin; He, Xin IEEE Journal of Photovoltaics, Vol. 10, Issue 5 https://doi.org/10.1109/jphotov.2020.3005086	journal	September 2020
Additivation of the ethylene–vinyl acetate copolymer (EVA) with maleic anhydride (MA) and dicumyl peroxide (DCP): the impact of styrene monomer on cross-linking and functionalization Luna, Carlos Bruno Barreto; da Silva Barbosa Ferreira, Eduardo; Siqueira, Danilo Diniz Polymer Bulletin, Vol. 79, Issue 9 https://doi.org/10.1007/s00289-021-03856-x	journal	August 2021
Analysis of the degradation of encapsulant materials used in photovoltaic modules exposed to different climates in China Han, Huili; Yan, Huan; Wang, Xuemeng Solar Energy, Vol. 194 https://doi.org/10.1016/j.solener.2019.10.014	journal	December 2019
Diffusion of UV Additives in Ethylene-Vinyl Acetate Copolymer Encapsulants and the Impact on Polymer Reliability Heidrich, Robert; Lüdemann, Marius; Mordvinkin, Anton IEEE Journal of Photovoltaics, Vol. 14, Issue 1 https://doi.org/10.1109/jphotov.2023.3333198	journal	January 2024
Crosslinking and post-crosslinking of ethylene vinyl acetate in photovoltaic modules Oreski, G.; Rauschenbach, A.; Hirschl, C. Journal of Applied Polymer Science, Vol. 134, Issue 23 https://doi.org/10.1002/app.44912	journal	February 2017
Measurement and simulation of dynamic mechanical loads on PV-modules Weiss, Karl-Anders; Assmus, Marcus; Jack, Steffen SPIE Proceedings https://doi.org/10.1117/12.824859	conference	August 2009
The Natural and Accelerated Evolution of EVA Adhesion Through Intermediate Exposures Thornton, Patrick; Bosco, Nick; Dauskardt, Reinhold H. IEEE Journal of Photovoltaics, Vol. 12, Issue 6 https://doi.org/10.1109/jphotov.2022.3195095	journal	November 2022
Field testing of thermoplastic encapsulants in high-temperature installations Kempe, Michael D.; Miller, David C.; Wohlgemuth, John H. Energy Science & Engineering, Vol. 3, Issue 6 https://doi.org/10.1002/ese3.104	journal	November 2015
Thermal decomposition of cross-linked polybutadiene and its copolymers Jiang, David D.; Levchik, Galina F.; Levchik, Sergei V. Polymer Degradation and Stability, Vol. 65, Issue 3 https://doi.org/10.1016/S0141-3910(99)00027-0	journal	September 1999
Photo- and thermal-oxidation of polyethylene: Comparison of mechanisms and influence of unsaturation content Gardette, Mélanie; Perthue, Anthony; Gardette, Jean-Luc Polymer Degradation and Stability, Vol. 98, Issue 11 https://doi.org/10.1016/j.polymdegradstab.2013.07.017	journal	November 2013
Creep in photovoltaic modules: Examining the stability of polymeric materials and components Miller, David C.; Kempe, Michael D.; Glick, Stephen. H. 2010 35th IEEE Photovoltaic Specialists Conference (PVSC) https://doi.org/10.1109/pvsc.2010.5615832	conference	June 2010
Effects of crystallinity and crosslinking on the thermal and rheological properties of ethylene vinyl acetate copolymer Sung, Y. T.; Kum, C. K.; Lee, H. S. Polymer, Vol. 46, Issue 25 https://doi.org/10.1016/j.polymer.2005.09.080	journal	November 2005
Photo-oxidation of ethylene-vinyl acetate copolymers Skowronski, T. A.; Rabek, J. F.; Rånby, B. Polymer Photochemistry, Vol. 3, Issue 5 https://doi.org/10.1016/0144-2880(83)90048-9	journal	January 1983
PV encapsulant formulations and stress test conditions influence dominant degradation mechanisms Uličná, Soňa; Sinha, Archana; Miller, David C. Solar Energy Materials and Solar Cells, Vol. 255 https://doi.org/10.1016/j.solmat.2023.112319	journal	June 2023
Mechanism of the Acid-Catalyzed Si−O Bond Cleavage in Siloxanes and Siloxanols. A Theoretical Study Cypryk, Marek; Apeloig, Yitzhak Organometallics, Vol. 21, Issue 11 https://doi.org/10.1021/om011055s	journal	May 2002
Melt functionalization of EVA copolymers with maleic anhydride Soares, Bluma G.; Colombaretti, Rodrigo S. C. Journal of Applied Polymer Science, Vol. 72, Issue 14 https://doi.org/10.1002/(SICI)1097-4628(19990628)72:14<1799::AID-APP1>3.0.CO;2-G	journal	June 1999
Dependence of adhesion on degradation mechanisms of ethylene co-vinyl acetate encapsulants over the lifetime of photovoltaic modules Thornton, Patrick; Moffitt, Stephanie L.; Schelhas, Laura T. Solar Energy Materials and Solar Cells, Vol. 244 https://doi.org/10.1016/j.solmat.2022.111818	journal	August 2022
Determining the degree of crosslinking of ethylene vinyl acetate photovoltaic module encapsulants—A comparative study Hirschl, Ch.; Biebl–Rydlo, M.; DeBiasio, M. Solar Energy Materials and Solar Cells, Vol. 116 https://doi.org/10.1016/j.solmat.2013.04.022	journal	September 2013
Determining the Crosslinking and Degradation Reaction Kinetics in Photovoltaic Encapsulants Using Accelerated Aging Liu, Kuan; Miller, David C.; Bosco, Nick 2024 IEEE 52nd Photovoltaic Specialist Conference (PVSC) https://doi.org/10.1109/PVSC57443.2024.10749611	conference	June 2024
Correlation of spatially resolved photoluminescence and viscoelastic mechanical properties of encapsulating EVA in differently aged PV modules: Correlation of spatially resolved photoluminescence and viscoelastic mechanical properties Schlothauer, Jan C.; Grabmayer, Klemens; Wallner, Gernot M. Progress in Photovoltaics: Research and Applications, Vol. 24, Issue 6 https://doi.org/10.1002/pip.2734	journal	January 2016
Evaluating and predicting molecular mechanisms of adhesive degradation during field and accelerated aging of photovoltaic modules Tracy, Jared; D'hooge, Dagmar R.; Bosco, Nick Progress in Photovoltaics: Research and Applications, Vol. 26, Issue 12 https://doi.org/10.1002/pip.3045	journal	July 2018
Multi angle laser light scattering evaluation of field exposed thermoplastic photovoltaic encapsulant materials Kempe, Michael D.; Miller, David C.; Wohlgemuth, John H. Energy Science & Engineering, Vol. 4, Issue 1 https://doi.org/10.1002/ese3.106	journal	January 2016
FTIR Investigation of EVA Chemical Bonding Environment and Its Impact on Debond Energy Spinella, Laura; Bosco, Nick IEEE Journal of Photovoltaics, Vol. 9, Issue 3 https://doi.org/10.1109/jphotov.2019.2904219	journal	May 2019
Encapsulant Adhesion to Surface Metallization on Photovoltaic Cells Tracy, Jared; Bosco, Nick; Dauskardt, Reinhold IEEE Journal of Photovoltaics, Vol. 7, Issue 6 https://doi.org/10.1109/jphotov.2017.2746572	journal	November 2017
The Thermal and Mechanical Properties of Poly(ethylene-co-vinyl acetate) Random Copolymers (PEVA) and its Covalently Crosslinked Analogues (cPEVA) Wang, Ke; Deng, Qibo Polymers, Vol. 11, Issue 6 https://doi.org/10.3390/polym11061055	journal	June 2019

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