A research team of the US National Renewable Energy Laboratory has analyzed N-Type Modules that were used in a commercial PV project of 3 MW in an attempt to assess the high relegation speed reported by the plant owner. The scientists discovered that Ultraviolet -induced demolition (UVID) was an important factor that influenced the performance of the facility.
Researchers of the National Renewable Energy Laboratory (NREL) of the US Department of Energy have investigated how ultraviolet can influence the performance of PV systems with the help of N-Type Solar modules and have not been designed to be bary who are not designed to be beat who have been designed those who are unpreted those who are not to be used to have been filled those who have been filled those who have been filled those who have been filled who have been bones that have been bones that are unguiten who have been filled. For assessing all risks of potential performance losses.
The scientists carried out their analysis on a 3 MW Commercial PV system that was deployed at an unknown location in a moderate zone of the United States. “The site was identified as underperforming by the owner, and Veldstroom (IV) curves indicated that modules had broken off about 2.4%/year compared to the nameplate,” they explained. “After about 6 years of implementation, four field modules and two unfinished spare parts were reserved for our studies.”
The system is based on N-Type modules based on passivated Emitter-Agste full diffuse (pert) modules of a non-specific manufacturer, but the scientists warned that their findings could be extended to other module technologies such as Tunnel Oxide Passivated Contact (Hjjunction). “There is evidence through laboratory studies that some of these cells are more sensitive to UVID, but there is a lack of confirmation that such a demolition takes place in the field,” the group emphasized.
For their analysis, the academics used the power voltage (IV) and Suns-VOC scanning, electroluminescence (EL) imaging, photoluminescence (PL) imaging, external quantumfficiency (EQE) measurements, dark lock-in thermography (dlit) and Energdon microscopy (Eds).
They also carried out damp heat (DH) and UV stress tests from combined with scanning spreading resistance Microscopy (SSRM), optical microscopy, the Fourier-transformation infrared spectroscopy (FTIR), High-quality liquid chromatography-specture-Specture-Specture-specture To assess the size of the module degradation.
The scientists discovered by EQE measurers that the analyzed modules Uvide losses members caused by cell area recumbine losses. They also identified a second cause of Uvid loss in the lack of zinc (ZN) in the metallization paste used for the analyzed modules.
“UV-exposure alone, but beyond the IEC 61215-2 MQT10 stands (15 kWh/m2280–400 Nm), reproduced the demolition of the surface, but not the raised series resistance, “they explained.” UV exposure of 67.5 kWh/m2 (200 – 400 Nm) was needed before there was a measurable power loss. Subsequent humid heat stress (1000 H 85/85) caused a serious increase in the series resistance of the UV-blot cells, but not the non-UV-stung cells. This suggests an important switch between these stress factors. “
Moreover, the research group exposed the modules to a testing of 1,000 hours that showed a further “serious” series of resistance breakdown, even in those panels with a metallization paste that contained Zn. “We attribute this to higher concentrations of acetic acid that is generated on the UV-blot area of the module, which leads to demolition of the grid line/cell interface and high series resistance,” said it.
The academics concluded that the current IEC standards only require minimal UV exposure, which can be harmful to accurate UVID loss assessments.
“The UV stress test that is currently included in the IEC 61215-2 standard is 15 kWh/m2 (MQT 10), which is usually about 2-3 months in the field, depending on the location (1.8 months on the specific utility site that is studied in this), which implies that UV effects can go unnoticed in the longer term, “they emphasized.
Their findings were presented in the study “UV + wet heat-induced power losses in fielded utility n-type si pv modules“Published in Progress in photovoltaic.
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