Degradation of Backsheets for Crystalline Photovoltaic Modules under Damp Heat Test
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The reliability of crystalline silicon photovoltaic (PV) modules is determined not only by the efficiency loss of thesilicon cells but also by the degradation of other components (ethyl vinyl acetate, ribbon, glass, and backsheet). Among thesecomponents, the backsheet provides electrical insulation and physical support, and acts as a barrier against moisture and weathering ofthe PV module. We investigated the degradation of different types of backsheets under damp heat conditions [95°C/85% relativehumidity (R.H), 85°C/85% R.H]. During the damp heat treatment, tensile tests were carried out to investigate the mechanicaldegradation of the backsheets. The molecular weight of the polyethylene terephthalate (PET) in the backsheets was measured by gelpermeation chromatography (GPC) to understand the intrinsic mechanism of degradation. After damp heat test, mechanicaldegradation of backsheet occurred significantly beyond passing the specified molecular weight region of PET film in backsheetmaterials. By finding the correlation between tensile strength and the molecular weight of the backsheets, our results make it possibleto improve the reliability of backsheets.
Abstract
The reliability of crystalline silicon photovoltaic (PV) modules is determined not only by the efficiency loss of thesilicon cells but also by the degradation of other components (ethyl vinyl acetate, ribbon, glass, and backsheet). Among thesecomponents, the backsheet provides electrical insulation and physical support, and acts as a barrier against moisture and weathering ofthe PV module. We investigated the degradation of different types of backsheets under damp heat conditions [95°C/85% relativehumidity (R.H), 85°C/85% R.H]. During the damp heat treatment, tensile tests were carried out to investigate the mechanicaldegradation of the backsheets. The molecular weight of the polyethylene terephthalate (PET) in the backsheets was measured by gelpermeation chromatography (GPC) to understand the intrinsic mechanism of degradation. After damp heat test, mechanicaldegradation of backsheet occurred significantly beyond passing the specified molecular weight region of PET film in backsheetmaterials. By finding the correlation between tensile strength and the molecular weight of the backsheets, our results make it possibleto improve the reliability of backsheets.
참고문헌 (30)
- D. L. King, "Photovoltaic Module Performance and Durability Following Long-Term Field Exposure", Prog. Photovoltaics, 8, pp.241~ (2000)
- I. V. Fisher, "Factors affecting the stability of CdTe", CdS solar cells deduced from stress tests at elevated temperature, 2003, pp.13, 289~
- M. A. Cluintana, "Commonly observed degradation in field-aged photovoltaic modules", Photovoltaic Specialists Conference (PVSC), 29th IEEE, pp.1436~ (2002)
- D. Wu, "Degradation of interfacial adhesion strength within photovoltaic mini-modules during damp-heat exposure", Prog. Photovoltaics, 22, pp.796~809 (2000)
- W. Gambogi, "The Role of Backsheet in Photovoltaic Module Performance and Durability", 26th European Photovoltaic Solar Energy Conference and Exhibition (PVSEC), pp.3325~3328 (2011)
- Y. Zhang, "Long-term reliability of silicon wafer-based traditional backsheet modules and double glass modules", RSC Adv, 5, pp.65768~65774 (2015)
- G. Oreski, "Aging mechanisms of polymeric films for PV encapsulation", Sol. Energy Mater. Sol. Cells, 79, pp.612~617 (2005)
- K. J. Geretschlager, "Raman and Infrared Microscopical Analysis of Multilayer Backsheets", 26th EU Photovoltaic Solar Energy Conference and Exhibition (PVSEC), pp.3499~3502 (2015)
- S. Venkatachalam, "Polyester", pp.75~98 (2012), InTech
- E. Wanga, "Failure Modes Evaluation of PV Module via Materials Degradation Approach", Energy Procedia, 33, pp.256~264 (2013)
- G. Oreski, "Delamination behaviour of multi-layer films for PV encapsulation", Sol. Energy Mater. Sol. Cells, 89, pp.139~151 (2005)
- J. C. Moore, "Gel permeation chromatography. I. A new method for molecular weight distribution of high polymers", J. Polym. Sci, 2, pp.835~843 (1964)
- P. Sánchez-Friera, "Analysis of degradation mechanisms of crystalline silicon PV modules after 12 years of operation in Southern Europe", Prog. Photovoltaics, 19, pp.658~ (2011)
- A. E. Hamielec, "Generalized Universal Molecular Weight Calibration Parameter in GPC", J. Liq. Chromatogr, 1, pp.111~120 (1978)
- G. D. Barber, "New Barrier Coating Materials for PV Module Backsheets", Photovoltaic Specialists Conf. 2002, 29th IEEE, pp.1541~1544 (2002)
- P. Hülsmann, "Impact of Permeation Properties and Backsheet-Encapsulant Interactions on the Reliability of PV Modules", IMECE, 4, pp.5~ (2012)
- M.D. Kempe, "Modeling of rates of moisture ingress into photovoltaic modules", Sol. Energy Mater. Sol. Cells, 90, pp.2720~2738 (2006)
- M. A. Hallam, "Relationship between tensile strength and molecular weight of highly drawn polyethylenes", J. Mater. Sci, 6, pp.975~976 (1987)
- P. Smith, "Tensile strength of highly oriented polyethylene. II. Effect of molecular weight distribution", J. Polym. Sci. Polym. Phys. Ed, 20, pp.2229~2241 (1982)
- F. D. Novoa, "Environmental mechanisms of debonding in photovoltaic backsheets", Sol. Energy Mater. Sol. Cells, 120, pp.87~93 (2014)
- A. Iguchi, "Evaluation of Degradation of PET Film by Partial Discharge Method", Mater. Sci. Appl, 5, pp.33~38 (2014)
- C. Sammon, "An FT-IR study of the effect of hydrolytic degradation on the structure of thin PET flms", Polym. Degrad. Stab, 67, pp.149~158 (2000)
- M. Edge, "Aspects of poly (ethylene terephthalate) degradation for archival life and environmental degradation", Polym. Degrad. Stab, 32, pp.131~153 (1991)
- R. C. Golike, "Kinetics of hydrolysis of polyethylene terephtalate films", J. Phys. Chem, 64, pp.895~898 (1960)
- E. Pirzadeh, "Hydrolytic and Thermal Degradation of PET Fibers and PET Granule: The Effects of Crystallization, Temperature, and Humidity", J. Appl. Polym. Sci, 106, pp.1544~1549 (2007)
- W. McMahon, "Physical properties evaluation of compounds and materials_Degradation Studies of Polyethylene Terephthalate", J. Chem. Eng, 4, pp.57~79 (1959)
- L. J. Fetters, "Connection between Polymer Molecular Weight, Density, Chain Dimensions, and Melt Viscoelastic Properties", Macromolecules, 27, pp.4639~4647 (1994)
- D. F. Farrar, "Hydrolytic degradation of polyglyconate B: the relationship between degradation time, strength and molecular weight", Biomaterials, 23, pp.3905~3912 (2002)
- P. J. Flory, "Tensile Strength in Relation to Molecular Weight of High Polymers", J. Am. Chem. Soc, 67, pp.2048~2050 (1945)
- N. Kim, "Study on the degradation of different types of backsheets used in PV module under accelerated conditions", Sol. Energy Mater. Sol. Cells, 120, pp.543~548 (2014)