Extended Accelerated Stress Testing (EAST) of Glass/Glass, Glass/Backsheet and Glass/Transparent Backsheet PV Modules: Influence of EVA and POE Encapsulants

Kumar, Akash; Pavgi, Ashwini; Hacke, Peter; Choudhury, Kaushik Roy; TamizhMani, GovindaSamy

doi:10.1109/pvsc48317.2022.9938862

Cited by 4 publications

(4 citation statements)

References 5 publications

(5 reference statements)

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“…Such UVF can be correlated to yellowing and modestly reduced short‐circuit current, 15 but the magnitude of the effect was not evaluated in this work in view of more significant degradation modes discussed below. A discussion in our sister paper concludes that the luminescing chromophores seen on the module front are associated with UV absorbers migrating from the cell‐bottom encapsulant layer during lamination 16 . Oxygen bleaching is primarily seen at the perimeter of the glass substrate modules from where oxygen can diffuse in; however, evolution of the UVF signal varies with other factors such as temperature.…”

Section: Resultsmentioning

confidence: 91%

“…these are 58, 80, 81, and 82. sulant layer during lamination. 16 Oxygen bleaching is primarily seen at the perimeter of the glass substrate modules from where oxygen can diffuse in; however, evolution of the UVF signal varies with other factors such as temperature. For example, the glass/glass modules exposed for 1.5 years with no thermal insulation on the back shows less evolution of fluorescence due to lower operating temperature compared with the modules with thermal insulation on the back (Figure 6).…”

Section: Encapsulant Degradationmentioning

confidence: 99%

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Evaluation of bifacial module technologies with combined‐accelerated stress testing

Hacke

Kumar

Terwilliger

et al. 2022

Progress in Photovoltaics

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In view of the increasing interest and market share of bifacial cells and modules, suitable substrates such as glass and transparent backsheets along with ethylene vinyl acetate (EVA) and polyolefin elastomer (POE) encapsulants were examined in combined‐accelerated stress testing (C‐AST) to evaluate and compare degradation modes. Testing with both monofacial and bifacial cells, we found that glass–glass modules with monofacial cells led to greater grid finger breakage than those with polymeric backsheets. This is attributed to previous X‐ray topography and modeling work showing higher stress in cells and interconnections in glass–glass modules than glass backsheet modules. Consistent with the objectives of C‐AST, which stresses modules at levels corresponding to the limits seen in the natural environment, we observed the UV‐fluorescence signatures of modules tested in C‐AST (considering the degradation associated with developing chromophores, moisture penetration, and photobleaching effects) to be like those in fielded modules, more so than other chamber stress testing implemented for comparison. We found light‐induced degradation (LID) in module types with regenerated (inactive) cells with C‐AST, suggesting the possibility of LID destabilization in some field conditions. We could also distinguish potential‐induced degradation (PID) on the back of the bifacial passivated emitter and rear cells (PERC) in C‐AST. Confirming with ex situ tests, we found polarization‐type PID most prevalent in glass‐glass modules with EVA as would be anticipated considering the greater leakage current through such module encapsulation. Unlike PID tests performed in the dark, which can lead to false positive PID test results, field‐representative illumination is experienced by the modules on the front and back sides while −1200 V system voltage is applied in C‐AST, supporting the conclusion that this module type with glass‐glass construction would be susceptible to PID in the field.

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Section: Resultsmentioning

confidence: 91%

Section: Encapsulant Degradationmentioning

confidence: 99%

Evaluation of bifacial module technologies with combined‐accelerated stress testing

Hacke

Kumar

Terwilliger

et al. 2022

Progress in Photovoltaics

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“…Currently, 90% of bifacial modules are made of GG (glass-to-glass) structures. 131 Lately, however, GB (glass-to-backsheet) structures have been developed because there are benefits in terms of lightness, cost reduction, ease of transportation, and installation. It was also confirmed that GB structures had lower PIDs than GG structures.…”

Section: Backsheetmentioning

confidence: 99%

Recent developments of polymer-based encapsulants and backsheets for stable and high-performance silicon photovoltaic modules: materials nanoarchitectonics and mechanisms

Kim,

Lim,

Kim

et al. 2024

J. Mater. Chem. A

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“…[19] In accelerated weathering experiments conducted in a laboratory setting, where various stress factors like heat, [20] humidity, [21] and UV light [22] are applied; alternatives such as TPO [23] and POE [24] have demonstrated superior optical, physical, chemical, [25] mechanical, and PID [26] performance compared to EVA. Further investigation extending from laminates [27] or glass/backsheet constructions as considered in this study to glass/transparent, glass/glass [28] and bifacial [29] (for a review on degradation in bifacial modules, cf. [30] ) constructions confirms the improvement potential underlying in devised encapsulation alternatives.…”

Section: Introductionmentioning

confidence: 99%

Assessing the Environmental Benefits of Extending the Service Lifetime of Solar Photovoltaic Modules

Paç,

Gok

2024

Global Challenges

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Requiring no fuel for generation and negligible material/energy for operation and maintenance, photovoltaic (PV) systems have environmental impacts mostly due to the production of modules and the commissioning of power plants. Thus, extending the service lifetime of these systems from 30 to 40 years through an enhanced lamination process for module production potentially reduces environmental impacts per unit energy generated. Life cycle assessment is employed to evaluate the environmental impacts under scenarios for resource utilizations for the new lamination process, operation and maintenance requirements in the extended service lifetime, and degradation rates of the devised modules. Extending the service lifetime significantly reduces environmental impacts across categories, with a 21–27% reduction in global warming potential on the pessimistic and optimistic ends. At least 20% impact reduction is achieved in most impact categories, even under a pessimistic scenario. Considering uncertainty models in the life cycle inventories, samples are generated for scenarios via Monte Carlo simulation, and with significant improvements with large effects in most environmental impact categories, deterministic impact comparisons are supported by ANOVA and Tukey tests. Production strategies for more durable and reliable PV modules have a significant potential in contributing to global sustainability efforts.

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Extended Accelerated Stress Testing (EAST) of Glass/Glass, Glass/Backsheet and Glass/Transparent Backsheet PV Modules: Influence of EVA and POE Encapsulants

Abstract: This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. U.S. Department of Energy (DOE) reports produced after 1991 and a growing number of pre-1991 documents are available free via www.OSTI.gov.

Cited by 4 publications

References 5 publications

Evaluation of bifacial module technologies with combined‐accelerated stress testing

Evaluation of bifacial module technologies with combined‐accelerated stress testing

Recent developments of polymer-based encapsulants and backsheets for stable and high-performance silicon photovoltaic modules: materials nanoarchitectonics and mechanisms

Assessing the Environmental Benefits of Extending the Service Lifetime of Solar Photovoltaic Modules

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