The ultraviolet fluorescence (UVF) imaging method has been widely used as a rapid and economic field inspection tool for investigating encapsulant discoloration of field-aged photovoltaic (PV) modules. In field-aged PV modules, encapsulant discoloration can result in a pronounced decrease in the short-circuit current. The spatial distribution of environmental stressors and therefore discoloration pattern over each cell of a module depends on the climate. In this article, we investigated the discoloration patterns (and their correlation with electrical parameters of modules and the extracted-cells from the modules) of ten modules produced at the same manufacturing facility and retrieved respectively from two distinct climates of Arizona (hot-dry; seven modules; 18 years of exposure) and Florida (hot-humid; three modules; ten years of exposure). In the Arizona modules, three distinct spatial patterns were observed in the UVF images: cell center region (intense browning); cell edge region (no browning); region between cell center; and cell edge region (light browning). However, in the Florida modules, only two distinct spatial distributions were observed: nonedge cell region (medium browning) and cell edge region (no browning). Furthermore, we employed a high-contrast UVF imaging technique to correlate the interdependence between the encapsulant discoloration pattern and the metallization/contact degradation pattern. For this correlative study, various experimental characterizations were carried out on both field-aged (Arizona and Florida) and unexposed modules and the cells extracted from the modules of the same model and they include: processed UVF and EL images, and I-V, TLM, optical microscopy, and XPS measurements.

中文翻译：

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紫外荧光图像与现场检索光伏模块性能损失的相关性


紫外荧光 (UVF) 成像方法已被广泛用作一种快速且经济的现场检查工具，用于研究现场老化的光伏 (PV) 模块的密封剂变色情况。在现场老化的光伏组件中，密封剂变色会导致短路电流显着下降。环境压力源的空间分布以及模块每个电池的变色模式取决于气候。在本文中，我们研究了在同一制造工厂生产的十个模块的变色模式（及其与模块的电气参数和从模块中提取的电池的相关性），并分别从亚利桑那州的两种不同气候（干热；干燥；干燥）中检索。七个模块；暴露 18 年）和佛罗里达州（湿热；三个模块；暴露十年）。在亚利桑那州模块中，在 UVF 图像中观察到三种不同的空间模式：细胞中心区域（强烈褐变）；细胞边缘区域（无褐变）；细胞中心之间的区域；和细胞边缘区域（浅棕色）。然而，在佛罗里达模块中，仅观察到两种不同的空间分布：非边缘细胞区域（中等褐变）和细胞边缘区域（无褐变）。此外，我们采用高对比度 UVF 成像技术来关联密封剂变色图案和金属化/接触退化图案之间的相互依赖性。对于这项相关研究，对现场老化（亚利桑那州和佛罗里达州）和未暴露的模块以及从同一模型的模块中提取的电池进行了各种实验表征，包括：处理后的 UVF 和 EL 图像以及 IV、TLM、光学显微镜和 XPS 测量。