不同气候环境下的单晶组件衰减对比

Comparison of study on the degradation of monocrystalline silicon photovoltaic modules exposed in different climates Huili HanSun Yat-Sen UniversityShunDe SYSU Institute for Solar Energy2019.06.04 1 Outline1. Research background2. Field and PV module information3. Degradation Analysis of the PV modules4. Results and outlook 2 Research background 3 Why and how we do these work 4 Experimental PV systems Accelerating testsStandards for assessment of module quality / Optimize evaluation method of PV plantResearch EVA; BacksheetTPT Rated value P 48 Wp， Voc 19.8 V， Isc 3.35 A, Vm 15.9 V， Im 3.02 A M75 moduleSM55 module Produce and installation 1992-1998 Location Shenzhen hot-humid climate Glass 3.2 mm; EVA; BacksheetTPT Rated value P 55 Wp， Voc 21.7 V， Isc 3.45 A, Vm 17.4 V， Im 3.15 A 12Location Climate Yearly Mean Temperature ℃ Extreme Temperatures ℃ Average Relative Humidity YearlyMeanPrecipitationmm Yearly Mean Insolation kWh/m2 Shenzhen Subtropical Monsoon 22 Min 0.2/Max 38.7 75.6 1933 1427 Dunhuang Temperate arid Continental 9.3 Min -28.5 /Max 43.6 39.9 38 1778 M75 modules SM55 modules 13 Degradation Analysis of the PV modules 14 SM55 moduels The average maximum power Pm , open-circuit voltage Voc , short-circuit current Isc and fill factor FF decreased by 24.62, 2.4, 7.72, and 16.25, respectively, as compared with the nameplate values Pmax Voc Isc Vm Im FFNameplate value 48.00 19.80 3.35 15.90 3.02 72.00 Testing value 41.83 19.64 3.14 15.10 2.77 67.81 Degradation （ ） 12.85 0.79 6.27 5.06 8.24 5.82 Pmax Voc Isc Vm Im FFNameplate value 55.00 21.7 3.45 17.4 3.15 73.00 Testing average value 41.46 21.18 3.18 14.88 2.78 61.39 Average Degradation （ ） 24.62 2.40 7.72 5.06 8.24 16.25M75 moduels The average maximum power Pm , open-circuit voltage Voc , short-circuit current Isc and fill factor FF decreased by 12.85, 0.79, 6.27, and 5.82, respectively, as compared with the nameplate values 15 It exists a significantly positive correlation between the degradation of Pm and FF with a correlation coefficient of 0.86, indicating that the reduction of Pm is mainly attributed to the decrease of FF, most probably caused by an increase of series resistance of the modules. The correlations between the degradation of Pm and of Voc , Isc , or FFSM55 moduels 16 The correlations between the degradation of Pm and of Voc , Isc , or FFM75 moduels The results illustrate that the degradation in power output is mainly due to the decrease of FF, most probably caused by an increase of series resistance of the modules. While the degradation of Isc causes less significant losses. 17 Analysis of EL defects a a PV module exposed in the field dark area in center of cells, b PV module exposed in the field dark area around the edge of cells, c the PV module kept indoor Three types of defects were observed. Defect A, is characterized by a dark area in the middle of the cell between the two bus- bars. Defect B,features a bright spot around the center point of the busbar. Defect C, is characterized by a dark border around the cells SM55 moduels 18l Some aggregations of needles are clearly detected on the surface of Ag grid in the dark area;l The resultsfromXPSandEDXindicatetheexistenceofsilveroxide and lead acetate in the needles, which confirm the oxidation of Agtogetherwiththecorrosionofleadoxide 19The cross-sectional SEM images of a solder interconnection area of a field-exposed module. A long crack between the solder layer and the Ag busbar is clearly observed. The EDX analysis of the solder layer showing the presence of Sn and Pb as expected, but also the presence of Cu dissolved from the ribbon forming brittle intermetallics, as well as the presence of oxygen and carbon probably coming from the acetic acid formation. 20 Because of the higher of the temperature difference between day and night and the wind and sand load, the additional cracks can be generated or electrical interconnections can be damaged by existing microcracks after mechanical stress or thermal cycling, leading to a significant degradation of the PV modules.Analysis of ELdefects The PV module exposed in the fieldM75 moduels c 21 Results and outlook 22 The average power degradation of SM55 modules is 24.62, or 1.54 per year, which exposed in Shenzhen. However, the average power degradation of M75 modules is 12.85, which exposed in Dunhuang. The degradation of power is main caused by the fill factor derease for both two types modules. In Shenzhen, becaused of the higher relative humidity, acetic acid evolving from the EVA after diffusion of moisture inside the module during aging caused the corrosion of the metal, which resulted in an increase of Rs In Dunhuang, due to the influence of temperature difference between day and night and the load of wind and sand, the electrode defect and cracked cells are the main failure modes, which are the main cuase of the degradation of fill factor. It can be seen that under different climatic conditions, due to the different environment stresses, there are different failure modes of PV modules, which result in the different degree of power degradation. Results 23 1. Select modules according to different climates, and study on the affect of environmental atresses such as humidity, temperature and UV dose, on the reliability of modules.2. We are building a living database of fielded modules in order to track the degradate trend, it would be a reference to the testing dose and sequence.3. A multi stress accelerated aging model was used to establish the relationship between indoor accelerated aging and outdoor aging, to evaluate material properties and the quality of PV module.4. Establish the differentiation evaluation system for different modules and PV system.Outlook Thank you86 17739728752hanhuili107126.com 24