Segbefia Oscar Kwame
Department of Engineering Sciences, University of Agder, 4879 Grimstad, Norway.
Heliyon. 2023 Aug 28;9(9):e19566. doi: 10.1016/j.heliyon.2023.e19566. eCollection 2023 Sep.
Moisture ingress into PV module in the presence of ultraviolet radiation, high temperature, and other environmental stressors can affect the optical integrity of the PV module. Optical degradation can take the form of delamination, discolouration of encapsulant, metal grids corrosion, and trapped moisture or chemical species. This can influence the photon absorption and current transport properties in the PV module bulk, which can affect the module operating temperature. In the present work, the relationship between optical degradation and temperature sensitivity of 20-year-old multicrystalline silicon field-aged PV modules have been investigated. The selected PV modules were characterized using visual inspection, current-voltage (I-V) characterization, temperature coefficients profiling, current resistivity profiling, infrared (IR) thermal, ultraviolet fluorescence (UV-F), and electroluminescence (EL) imaging. PV modules affected by optical degradation show weak fluorescence and luminescence signal intensities. The average difference in cell temperature () between the warmest and coldest cell for the PV modules investigated was found to be around 10 ± 2 °C and the average power degradation rate was approximately 0.8% per year. The underlying factor for the observed degradation is attributed to the degradation in the temperature coefficients of open circuit voltage () and maximum power point voltage (). The average temperature coefficient of efficiency () of the modules was found to be around -0.5%/°C. Finally, a temperature dependent resistivity method for extracting temperature coefficients from IR thermal data of PV modules has been proposed.
在紫外线辐射、高温及其他环境应激因素存在的情况下，水分进入光伏组件会影响光伏组件的光学完整性。光学降解可能表现为分层、封装材料变色、金属网格腐蚀以及水分或化学物质的截留。这会影响光伏组件本体中的光子吸收和电流传输特性，进而影响组件的工作温度。在本研究中，对使用了20年的多晶硅现场老化光伏组件的光学降解与温度敏感性之间的关系进行了研究。通过目视检查、电流-电压（I-V）特性表征、温度系数分析、电流电阻率分析、红外（IR）热成像、紫外荧光（UV-F）和电致发光（EL）成像对所选光伏组件进行了表征。受光学降解影响的光伏组件显示出较弱的荧光和发光信号强度。在所研究的光伏组件中，最热电池和最冷电池之间的电池温度（）平均差异约为10±2°C，平均功率降解率约为每年0.8%。观察到的降解的潜在因素归因于开路电压（）和最大功率点电压（）的温度系数的降解。发现这些组件的效率（）平均温度系数约为-0.5%/°C。最后，提出了一种基于温度的电阻率方法，用于从光伏组件的红外热数据中提取温度系数。
