紫外湿热条件下复合型透明光伏背板的老化行为研究

Aging Behaviour of Composite Transparent Photovoltaic Backsheets Under UV Moist Heat Conditions

随着双面发电系统的逐渐普及,为了满足其组件稳定运行25年的要求,透明背板的可靠性也在逐步提升。湿热老化和光老化是导致背板老化的主要环境因素,本文采用紫外湿热加速老化试验,观察透明背板的水蒸气透过率、透光率、拉伸性能、层间剥离性能四个方面性能的变化情况,并采用FTIR、DSC、光学显微镜等测试手段研究其变化机理。结果显示,温度85℃相对湿度85%的45 kWh紫外湿热试验期间,试验透明背板的分子结构、结晶度、透光率、水蒸气透过率尚未发生显著变化;背板PET面的微观结构裂纹随试验进行逐渐增多,导致透明背板的拉伸性能明显劣化;样品拉断时,用剥离最大应力可以较准确地表征复合背板层间粘接性能的变化,胶水粘接强度在(0~15)kWh迅速上升,后在(15~45)kWh缓慢下降。

With the gradual popularisation of double-sided power generation systems,the reliability of transparent backsheets has been gradually improved in order to meet the requirement of 25 years of stable operation of their components.Humidity and heat aging and light aging are the main environmental factors leading to the aging of backsheets.In this paper,Uv humidity and heat accelerated aging test is used to observe the changes in four aspects of transparent backsheets performance:water vapour transmission rate,light transmittance,tensile properties,and interlaminar peeling properties,and to study the mechanism of the change by using test methods such as FTIR,DSc,and optical microscopy.The results show that the molecular structure,crystallinity,light transmittance and water vapour transmission rate of the transparent backsheet have not yet changed significantly during the 45 kWh UV hygrothermal test at a temperature of 85 C and a relative humidity of 85%:the microstructural cracks on the PET surface of the backsheet gradually increase with the test,which leads to a significant deterioration in the tensile properties of the transparent backsheet;the maximum stress of the stripping can be used to characterize the inter-layer bonding properties of the composite backsheet more accurately when the samples are pulled off.When the sample is pulled off,the peeling maximum stress can more accurately characterise the change of the interlayer bonding performance of the composite backsheet,and the adhesive bonding strength rises rapidly from 0 to 15 kwh,and then decreases slowly from 15 to 45 kWh.