A Custom High-Throughput Optical Mapping Instrument for Accelerated Stress Testing of PV Module Materials

Journal Article · Sat Nov 13 00:00:00 UTC 2021 · IEEE Journal of Photovoltaics

DOI: https://doi.org/10.1109/jphotov.2021.3122925 · OSTI ID:1835079

Khan, Imran S.  ^[1]; Morse, Joshua ^[1]; White, Robert R. ^[1]; Miller, David C.  ^[1]

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1. National Renewable Energy Lab. (NREL), Golden, CO (United States)

The performance and integrity of photovoltaic (PV) modules and materials may be assessed through optical characterizations. We have developed a custom optical mapping instrument (OMI) to improve measurement throughput time, facilitate automated measurements, allow for localized specimen examination, obtain spatial information relative to commercial benchtop spectrophotometer instruments, and provide automated data analysis. Both the key components and the methods used to improve the measurements are described. The measurement precision for the OMI is benchmarked for hemispherical transmittance relative to a previous round-robin study for commercial spectrophotometers. In addition to the unique instrument developed in this study, new insights have emerged from the examination of specimens from previous experiments, including: the depletion of the UV absorber is revealed for specimens beyond a certain size after artificial ultraviolet (UV) weathering; an optical degradation by internal haze formation is confirmed following Damp Heat (85 °C/85% relative humidity) testing; the better uniformity of the wear pattern for falling sand abrasion is used to select the DIN 52348 fixture over the ASTM D968 fixture; and the greater local (in the order of millimeters) heterogeneity of surface contamination in the soiling-prone location of Dubai relative to Kuwait. The results of the UV study have already been used to improve the standardized weathering of encapsulants. The example for Damp Heat testing is given to increase awareness of a degradation believed to be ubiquitously occurring in safety and design-type qualification testing of PV modules.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
• Grant/Contract Number: AC36-08GO28308
• OSTI ID: 1835079
• Report Number(s): NREL/JA-5K00-78974; MainId:32891; UUID:9406442e-acf2-4268-8016-be35b00f7a8a; MainAdminID:63414
• Journal Information: IEEE Journal of Photovoltaics, Journal Name: IEEE Journal of Photovoltaics Journal Issue: 1 Vol. 12; ISSN 2156-3381
• Publisher: IEEECopyright Statement
• Country of Publication: United States
• Language: English