摘要：
本工作对一批由西门子公司生产的SM55单晶光伏组件在深圳海边户外运行17年后的电性能失效原因进行了探究.944块组件的平均最大功率 (Pmax) 衰减23. 35％, 电性能参数变化主要表现为填充因子 (FF) 和短路电流 (Isc) 明显下降.观察组件的EL和红外热图像发现, 主栅处发亮和电池中间黑区是EL图像中的主要缺陷, 而电池脱焊可能是造成这批组件填充因子明显下降的主要原因.通过扫描电镜-能谱仪 (SEM与EDS) 和X射线光电子能谱仪 (XPS) 对电池表面细栅线进行进一步分析, 发现电池黑区部分正面细栅处有醋酸铅等针状物质形成, 导致银栅线接触电阻和金属电阻增大.旧组件光伏玻璃表面受到污染后, 靠边框部位有粘附性积灰, 导致光伏玻璃透光率下降, 而边缘处玻璃透光率下降更为显著, 从而使得组件的Isc下降.同时采用正常片、EL正常的高串阻与云片高串阻三种电池片制备样品组件, 并通过湿热实验来模拟电池制备因素对脱焊的影响, 发现EL正常的高串阻电池组件进行湿热试验后, 主栅处EL图像出现发亮现象, 红外热图像显示EL发亮处温度相应较高.这说明EL正常的高串阻电池在湿热环境下可能会增加主栅处脱焊和腐蚀的风险.%The electrical performance failure of a batch of SM55 mono-crystalline silicon PV modules was carried out in this study. These modules were manufactured by Siemens Solar Company, installed in the seaside of Shenzhen and in service for 17 years. The average maximum power (Pmax) degradation of 944 modules was 23. 5％, which was mainly caused by the serious reduction of fill factor (FF) and short-circuit (Isc) of module. It could be easily found from the EL and IR images of the modules that brightness along the busbar, which caused by the solder bond failure, and the dark area in the middle of the solar cell were the main defects in EL image. That might be the main reason for the reduction of the FF of the module. Further observation and analysis were conducted on the front fingers of the solar cell by scanning electron microscopy (SEM) , energy dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS) . It was found that there was lead acetate needle-like substance formed in the front fingers of the dark area in the solar cell, resulting in the increase of contact resistance and metal resistance. The surface of PV glass has been contaminated, and there was adhesive dust on the edge of PV glass, which led to the drop of the transmittance of the PV glass. A more serious decrease in transmittance has been found at the edge of PV glass, causing a significant decrease of Iscof the module.Meanwhile, PV module samples were prepared, some modules used normal solar cell, some modules used the high series resistance solar cell with normal EL image and some modules used the high series resistance solar cell. These PV module samples were accelerated degradation under damp-heat test to simulate the impact of high square resistance on the solder bond failure. The results showed that bright spot appeared along the busbar of the high series resistance solar cell with normal EL image module, there was a corresponding higher temperature of the bright spot shown in IR image. This indicates that the high series resistance solar cell with normal EL image may promote the risk of solder bond failure and corrosion of busbar in a hot and humid environment.
