Prediction of Climate-Specific Degradation Rate for Photovoltaic Encapsulant Discoloration

Journal Article · Thu May 14 00:00:00 EDT 2020 · IEEE Journal of Photovoltaics

DOI:https://doi.org/10.1109/jphotov.2020.2989182· OSTI ID:1660166

Sinha, Archana ^[1]; Gopalakrishna, Hamsini ^[1]; Bala Subramaniyan, Arun ^[1]; Jain, Deepak ^[1]; Oh, Jaewon ^[2]; Jordan, Dirk ^[3]; TamizhMani, GovindaSamy ^[1]

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1. Arizona State Univ., Mesa, AZ (United States). Photovoltaic Reliability Lab.
2. Arizona State Univ., Mesa, AZ (United States). Photovoltaic Reliability Lab.; Appalachian State Univ., Boone, NC (United States)
3. National Renewable Energy Lab. (NREL), Golden, CO (United States)

Encapsulant discoloration is a well-known field degradation mode of crystalline-silicon photovoltaic modules, particularly in the hot climate zones. The discoloration rate is influenced by several weathering factors, such as UV light, module temperature, and humidity, as well as the permeability of oxygen into the module. Here, a rate dependence model employing the modified Arrhenius equations to predict the degradation rate for encapsulant discoloration in different climates is presented. Two modeling approaches are introduced, which utilize the field and accelerated UV testing degradation data in conjunction with the field meteorological data to determine the acceleration factor for encapsulant browning. A novel method of accelerated UV stress testing at three simultaneous module temperatures in a single environmental chamber test run is implemented to estimate the activation energy for browning. The test was performed on three field-retrieved modules to capture the wear-out failure mechanism. The degradation in short-circuit current Isc rather than maximum power is used as a decisive parameter for the discoloration analysis. Furthermore, the developed model has been used to predict the Isc degradation rate for the Arizona field characterized by a hot and dry climate and is validated against the field-measured value. It has also been applied to other climate types, e.g., the cold and dry climate of New York.

• 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
• Grant/Contract Number: AC36-08GO28308
• OSTI ID: 1660166
• Report Number(s): NREL/JA--5K00-77554; MainId:27490; UUID:8182aeeb-d12b-43f9-87dd-8291d6df8efe; MainAdminID:15231
• Journal Information: IEEE Journal of Photovoltaics, Journal Name: IEEE Journal of Photovoltaics Journal Issue: 4 Vol. 10; ISSN 2156-3381
• Publisher: IEEE
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
Arrhenius model
acceleration factor
activation energy
degradation rate
discoloration
encapsulant
photovoltaic module