The thermo-mechanical degradation of ethylene vinyl acetate used as a solar panel adhesive and encapsulant

Badiee, Amir; Ashcroft, Ian; Wildman, Ricky D.

doi:10.1016/j.ijadhadh.2016.03.008

Cited by 76 publications

(36 citation statements)

References 25 publications

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“…A significant change for neat EVA was observed at around 78 °C. According to A. Badie et al 32 , it can be associated with internal structural changes or crystallization transitions of the matrix.…”

Section: Dsc Analysismentioning

confidence: 99%

Processing and characterization of UHMWPE composite fibres with alumina particles in poly(ethylene-vinyl acetate) matrix

Zec

Tomić

Zrilić

et al. 2017

Journal of Thermoplastic Composite Materials

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Processing of hybrid composites represents a challenge for engineers where the aim is to establish compatibility among several materials. The aim of this study is to evaluate the effects of different size and morphology of alumina fillers on the mechanical and thermal properties of the composite fibers based on ultra-high molecular weight polyethylene fibers (UHMWPE).These fibers have an outstanding elastic modulus and they are compatible with nonpolar sequences of the poly(ethylene-co-vinyl acetate) (EVA) matrix. Compared to the fibers, inferior mechanical properties of the matrix can be improved using alumina particles. Commercial Al 2 O 3 nanoparticles, commercial whiskers and synthesized particles of Al 2 O 3 doped with iron oxide, incorporated in different weight percent were used as fillers. The UHMWPE fibers were impregnated using the solution of EVA in toluene with dispersed particles. FT-IR and FE-SEM were used for structural examination. Tensile testing revealed increasing of modulus of elasticity and strengths of obtained hybrid composite fibers. Thermal gravimetry showed improved thermal stability up to 350°C of the hybrid composite fibers with alumina particles doped with iron oxide. Results of tested samples showed that the best mechanical properties were for hybrid composite fibers with 1 wt.% of iron doped alumina filler.

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Section: Dsc Analysismentioning

confidence: 99%

Processing and characterization of UHMWPE composite fibres with alumina particles in poly(ethylene-vinyl acetate) matrix

Zec

Tomić

Zrilić

et al. 2017

Journal of Thermoplastic Composite Materials

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“…The encapsulation of silicon (Si) cells by the use of EVA helps in guarding them against various field stressors such as humidity, thermal extremes, mechanical damage, and UV radiation . The most commonly used VA content for such an application is around 28–33% . However, there have been no systematic studies on exploring the usage of EVA outside this composition range as encapsulate materials.…”

Section: Introductionmentioning

confidence: 99%

Effect of vinyl acetate content on the photovoltaic‐encapsulation performance of ethylene vinyl acetate under accelerated ultra‐violet aging

Sharma

Desai

Singh

et al. 2019

J of Applied Polymer Sci

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The vinyl acetate (VA) content in ethylene vinyl acetate (EVA) can significantly affect its performance as an encapsulant in photovoltaic modules under field conditions. EVA films of varying VA content (18, 24, 33, and 40%) have been prepared using twin screw extruder with the necessary additives and subsequently cured at 150 C. All the EVA films have been subjected to UV radiation at a wavelength of 340 nm for 1000 and 2000 h to simulate accelerated field aging. The effects of accelerated aging on the gel content, mechanical properties, transmittance, Fourier transform infra-red (FTIR) spectra, thermal stability, degree of crystallinity, and yellowness have been studied. The observations made in this study of UV aging up to 2000 h suggests that the optimum range of VA content in EVA should be between 18 and 33% by weight. VA content beyond 40% degrades almost all properties needed for an encapsulate material after aging of only 2000 h. VA content of around 18% is the most stable under UV aging conditions but has a slightly lower value of transmittance for the unaged sample although the difference in transmittance between different specimens decreases with UV aging.

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“…Heat flow was measured over 2 heating and cooling cycles, administered from −40°C to 150°C at a heating rate of 10°C per minute, with 5‐minute dwells at the minimum and maximum of each cycle. Equation was used to evaluate χ c :

χ_{c} = \frac{{Δ H}_{f}}{{Δ H}_{f}^{italicPE}} \times 100

in which the enthalpy of fusion, Δ H f , was measured by integrating the area beneath the endothermic peak of the second heating cycle and the enthalpy of fusion of 100% crystalline polyethylene (PE), Δ H f PE (290 J/g), was taken from literature . Note that this normalization is a typical procedure for PE copolymers such as EVA and allows for a more reliable comparison of PE‐based materials because of a well‐defined reference point.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Ethylene vinyl acetate copolymer (EVA) has for decades been the predominant module encapsulant choice as it is inexpensive, possesses favorable mechanical properties, and initially adheres well to module components. Given the importance of encapsulation in preserving module performance, degradation of bulk EVA in the presence of heat, humidity, and/or ultraviolet (UV) radiation has been investigated extensively . While some studies have proposed correlations between climate characteristics and degradation, only a few have investigated the impact of terrestrial stresses on adhesion for actual EVA‐based modules .…”

Section: Introductionmentioning

confidence: 99%

“…Given the importance of encapsulation in preserving module performance, degradation of bulk EVA in the presence of heat, humidity, and/or ultraviolet (UV) radiation has been investigated extensively. [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] While some studies have proposed correlations between climate characteristics and degradation, 34,35 only a few have investigated the impact of terrestrial stresses on adhesion for actual EVA-based modules. [36][37][38] Notably, none of them include the reliable quantitative adhesion data for developing predictive degradation models for decade-long field operation.…”

Section: Introductionmentioning

confidence: 99%

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Evaluating and predicting molecular mechanisms of adhesive degradation during field and accelerated aging of photovoltaic modules

Tracy

D’hooge

Bosco

et al. 2018

Progress in Photovoltaics

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Extending photovoltaic (PV) module lifetimes beyond 30 years is a goal of significant priority. A challenge that must first be addressed, however, is the development of a predictive reliability model that captures the synergy of terrestrial stressors on module degradation, particularly at encapsulant interfaces. Using a metrology designed specifically for PV modules, a comprehensive study of the widely used ethylene vinyl acetate encapsulant was performed in which encapsulant adhesion was evaluated as a function of environmental stressors (UV exposure, temperature, and humidity) for modules aged both under accelerated lab and internationally located field conditions for months to nearly 3 decades. Mechanical and chemical characterization methods are combined with fundamental polymer reaction engineering to unravel the degradation processes active at the molecular scale that lead to encapsulant delamination. An analytical and modular model framework is put forward enabling the prediction of long‐term PV module durability, starting from fundamental principles at the molecular level and explicitly accounting for bond rupture events in the bulk encapsulant and at the encapsulant interfaces. Successful parameter tuning to adhesion data indicates a dominant occurrence of deacetylation, β‐scission, and hydrolytic depolymerization, respectively. The model contributes to the longstanding challenge of predicting module lifetimes in any geographic location while minimizing time‐consuming and costly aging studies.

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The thermo-mechanical degradation of ethylene vinyl acetate used as a solar panel adhesive and encapsulant

Cited by 76 publications

References 25 publications

Processing and characterization of UHMWPE composite fibres with alumina particles in poly(ethylene-vinyl acetate) matrix

Processing and characterization of UHMWPE composite fibres with alumina particles in poly(ethylene-vinyl acetate) matrix

Effect of vinyl acetate content on the photovoltaic‐encapsulation performance of ethylene vinyl acetate under accelerated ultra‐violet aging

Evaluating and predicting molecular mechanisms of adhesive degradation during field and accelerated aging of photovoltaic modules

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