Fang Li , Dylan J. Colvin , Viswa Sai Pavan Buddha , Kristopher O. Davis , Govindasamy Tamizhmani
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引用次数: 0
Abstract
Fielded photovoltaic (PV) modules often exhibit series resistance-related defects, mainly due to solder bond degradation and metallization corrosion. To quantitatively analyze the series resistance increase in fielded modules, we conducted a detailed investigation on two sets of modules, employing two complementary techniques, electroluminescence (EL) and infrared (IR) imaging. The dependence of EL image characteristics on module temperature, as revealed in IR images, was a key focus of this study. The first and second sets of modules were exposed in Florida (hot and humid climate) and Arizona (hot and dry climate) over 10 years and 18 years, respectively. The resistive defect patterns obtained using EL and IR images showed a closer correlation for the Florida modules compared to the Arizona modules as the Florida modules primarily experience solder bond degradation. EL and IR images were acquired at five current injection levels (i.e., 0.1, 0.3, 0.5, 0.7, 1.0 x short circuit current) and two exposure times (i.e., 60 s and 300 s) and used to develop and report a new curve fitting method for estimating the external series resistance. The results indicate that inaccurate temperature determinations from IR images can lead to underestimations (up to 23 %) in EL-based external series resistance estimates. For the most accurate series resistance estimation, especially in modules with severe thermal defects and series resistance deterioration, the study recommends obtaining EL and IR images within 60 s of the current injection time. This study also reports a Monte Carlo simulation assessing the impact of EL and IR characteristics on the accuracy of external series resistance estimations.
现场安装的光伏(PV)组件通常会出现与串联电阻相关的缺陷,这主要是由于焊点降解和金属化腐蚀造成的。为了定量分析现场组件中串联电阻的增加,我们采用电致发光 (EL) 和红外 (IR) 成像这两种互补技术,对两组组件进行了详细调查。红外图像显示的电致发光图像特征与组件温度的关系是本次研究的重点。第一组和第二组组件分别在佛罗里达州(炎热潮湿气候)和亚利桑那州(炎热干燥气候)暴露了 10 年和 18 年。与亚利桑那州的组件相比,佛罗里达州组件使用 EL 和 IR 图像获得的电阻缺陷模式显示出更密切的相关性,因为佛罗里达州的组件主要经历焊料粘接退化。在五种电流注入水平(即 0.1、0.3、0.5、0.7、1.0 x 短路电流)和两种曝光时间(即 60 秒和 300 秒)下获取的 EL 和 IR 图像用于开发和报告一种新的曲线拟合方法,以估算外部串联电阻。结果表明,根据红外图像确定的温度不准确会导致基于 EL 的外部串联电阻估算值被低估(最高可达 23%)。为获得最准确的串联电阻估计值,尤其是在存在严重热缺陷和串联电阻劣化的模块中,该研究建议在电流注入时间后 60 秒内获取 EL 和红外图像。本研究还报告了蒙特卡罗模拟,评估 EL 和 IR 特性对外部串联电阻估算准确性的影响。
期刊介绍:
Solar Energy welcomes manuscripts presenting information not previously published in journals on any aspect of solar energy research, development, application, measurement or policy. The term "solar energy" in this context includes the indirect uses such as wind energy and biomass