Field-Aged Glass/Backsheet and Glass/Glass PV Modules: Encapsulant Degradation Comparison

Patel, Aesha P.; Sinha, Archana; TamizhMani, GovindaSamy

doi:10.1109/jphotov.2019.2958516

Cited by 38 publications

(34 citation statements)

References 17 publications

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“…The enthalpies gradually decreased with the increase in UV doses in UV-DH combined tests (Figure 11b). Furthermore, only small variations The decrease in the melting enthalpy is a good indicator for material/polymers degradation [32]. The enthalpy measured in the EVA decreased after the first step of DH aging (500 h), indicating a decrease in the average size of the crystallites of aged EVA, and then remained constant independently of the backsheet type used (Figure 11a).…”

Section: Backsheet Comparison: Determination Of Eva Melting Enthalpymentioning

confidence: 99%

“…Additionally, a recent study of combined accelerated aging tests has drawn attention [26]. The results of most studies indicate that despite the investigation of EVA degradation using Fourier Transform Infra-Red spectroscopy (FTIR-ATR) [17][18][19][20]24,25,27], Raman spectroscopy [25,28], Differential Scanning Calorimetry (DSC) [15,22,24,25,[29][30][31][32][33][34][35][36] and tensile tests [24,37], the correlation of EVA chemical and thermal properties with stress factor changes remains unclear.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Backsheet Properties on PV Encapsulant Degradation during Combined Accelerated Aging Tests

et al. 2020

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Long-term photovoltaic (PV) module reliability is highly determined by the durability of the polymeric components (backsheet and encapsulation materials). This paper presents the result of experiments on encapsulant degradation influenced by the backsheet permeation properties. Towards this goal, one type of ethylene/vinyl acetate copolymer (EVA) was aged in glass/EVA/backsheet laminates in accelerated aging tests (up to 4000 h for Damp-Heat (DH) and up to 480 kWh/m2 for UV and UV-DH combined). The samples contained three backsheets with different permeation properties to examine their impact on EVA degradation. Thermal and chemical characterization shows that the EVA degradation is stronger with the glass–EVA–polyamide (PA)-based backsheet than with the polyethylene terephthalate (PET)-based backsheets. The higher oxygen transmission rate (OTR) of the PA-based backsheet may increase photo-oxidation and aggravating the degradation of EVA in the laminates. Furthermore, FTIR results were used to demonstrate the effect of damp heat exposure on the EVA interfaces, showing an accelerated degradation at the glass–EVA interface. The comparison of accelerated aging stress factors reveals that EVA suffers the strongest chemical and optical degradation when high UV, high temperature and high relative humidity are combined simultaneously.

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Section: Backsheet Comparison: Determination Of Eva Melting Enthalpymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Backsheet Properties on PV Encapsulant Degradation during Combined Accelerated Aging Tests

et al. 2020

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“…Browning of EVA negatively impacts the power output and short circuit current of the module by decreasing the light reaching the solar cell [ 30 , 39 , 40 , 42 ]. This was also observed in Type B modules which showed a 26.18% drop in the short circuit current, as can be seen in Fig 9.…”

Section: Resultsmentioning

confidence: 99%

Assessing the reliability and degradation of 10–35 years field-aged PV modules

Noman

Ahmad

et al. 2022

PLoS ONE

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The objective of this study was to conduct a reliability analysis on photovoltaic (PV) modules from the oldest PV installation site in Pakistan. Four sets of modules; Type A & B (30 years old), Type C (10 years old), and Type D (35 years old) were identified for this analysis. It has been observed that modules have shown degradation after working for a good number of years in the field. Comparing with nameplate data (available for Type B & C only), a drop of 28.68% and 2.99 percentage points (pp) was observed in the output power (Pmax) and efficiency (Eff.) respectively for Type B, while a drop of 22.21% and 4.05 pp was observed in Pmax and Eff. respectively for Type C. A greater drop in ISC and Pmax was observed in Type B, which is attributed to severe browning of EVA in them. While the greater drop in Pmax, in case of Type C, is attributed to the poor quality of materials used. Amongst the different defects observed, the junction box defects which include cracking and embrittlement, etc., and backsheet defects which include discoloration, delamination and cracking, etc. were found in all four types of modules. Other defects include browning of EVA, observed in Type B and D, and corrosion of frame and electrical wires, found in Type A, B, and D. This first-ever study will provide valuable information in understanding the degradation mechanism and henceforth, improving the long term reliability of PV modules in the humid-subtropical conditions of Pakistan.

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“…Polyamide backsheets were the most common types (reported from 12 sites) which were found during analysis and is certainly a known critical material [8]. Other critical material stacks were F-C/PET/PP (8 sites) and PET based structures (e.g., PET/PET/PET) (4 sites).…”

Section: Resultsmentioning

confidence: 99%

Advanced analysis of backsheet failures from 26 power plants

et al. 2021

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Backsheet degradation is a known reliability issue affecting field-exposed photovoltaic (PV) modules power plants. In this work, we present lessons learned during the last three years, examining modules from 26 power plants in the TestLab PV Modules at Fraunhofer ISE. The basis is a description of the currently observed backsheets and associated degradation features as for example backsheet chalking, cracks in different layers and chemical changes in composition. Furthermore, we lay out analytical methods for initial and more detailed analysis of the failures and module materials. For example, a method designated as “flashlight test” has been found to provide a quick and straightforward method to identify damaged polypropylene (PP) layers within backsheets. Furthermore, scanning acoustic microscopy (SAM) and a comparison of different variants of FTIR spectroscopy are presented.

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Field-Aged Glass/Backsheet and Glass/Glass PV Modules: Encapsulant Degradation Comparison

Cited by 38 publications

References 17 publications

Effect of Backsheet Properties on PV Encapsulant Degradation during Combined Accelerated Aging Tests

Effect of Backsheet Properties on PV Encapsulant Degradation during Combined Accelerated Aging Tests

Assessing the reliability and degradation of 10–35 years field-aged PV modules

Advanced analysis of backsheet failures from 26 power plants

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