2014 China PV power plant construction will reach 10-12GW, accounting for a quarter of the world's. To November, the domestic photovoltaic power plant started to usher in the peak period. Currently, however, has built PV power plant quality large-scale problems of extraordinary attention, including large ground station components attenuation and snail patterns outbreaks and other issues. The author of the owner of Qinghai, Xinjiang, part of the power plant in Zhangjiakou conducted research or talk to visit and found the well-known brand component parts used in power plants of 1-2 years on the assembly severe decay, snail pattern is a large-scale outbreak.
Beijing CGC relevant responsible person said, the current problems of photovoltaic power plants focused on the quality of equipment, plant design, power plant construction and power plant operation and maintenance and so on. Through the 425 plant test found that PV modules mainly hot spots, cracked and power attenuation and other quality problems. In power attenuation, for example, runs at the center of last year's 11 large-scale field testing ground station components for about a year, after taking into account the uncertainty of device discovery, about 50% of the component attenuation between 5% to 10% , about 30% of the components of the power attenuation of more than 10%, 8% of component has more than 20% decay. This means that the 25 component companies generally promise only 20% attenuation of warranty, and some products had only one year to run close to or even beyond the bottom line.
Two years before the Chinese PV industry excessive investment, coupled with low investment threshold, leading to the outbreak of capacity, followed by Gresham's law. Because many developers do not understand the power station component technology and system technology, simply use a lot of investment income in order to pursue cheap, low-quality components. Through research on the domestic power plants, power plants do well attenuation, attenuation of the annual assembly of generating capacity can do 0.1%, while some components of the product has not been tested, attenuation actually over 60%. Solar PV modules in plastic parts is its quality short board. Plastic parts junction box, sealing silicone, backplanes and EVA film . EVA film which is the weakest part. EVA film, EVA resin and additives by heating the extrusion. Because EVA resin itself readily hydrolyzed to produce acetic acid, has become an important component of many different reasons for power attenuation problems.
Acetic acid sodium salt of the glass can be caused by the reaction of sodium ion migration resulting in attenuation of power components (PID attenuation), the gate line can also be induced by oxidation reaction of the silver pattern phenomenon occurs snails. Japan Chemitox by cells immersed in a dilute solution of acetic acid concentration observed certain changes in the silver grid lines can be gradually proved acetate silver gate line cells surface corrosion narrowed.
Through experimental simulation harsh natural environment, 85 degrees Celsius, 85% humidity and applied voltage 1000V, aged 96 hours, the current use of inexpensive EVA film PV modules are 20% -60% of decay occurs. This means that if the domestic production of components in a power plant environment is not the ideal situation that may happen in 10 years on a large scale attenuation. Even with 96 hours or 192 hours decay test whether PV modules can guarantee 25 years of life is still unknown. Some large temperature difference between morning and evening, or near the water's edge PV plant is crisis-ridden, and these sites due to the low price or no other use is often easy to become a PV power plant is selected.
With the development of PV technology, power users, many countries have anti-decay properties of components made progressively more stringent requirements. For example PVEL PV modules have been raised through 600 hours of anti-PID aging test, while Japan Chemitox raised the need to retain in the case of the module surface water film anti-PID test component attenuation performance. For snail pattern problem of PV modules, there is no pretty standard test methods, but most will be made of cells cracked state assembly and then made alternately aging and exposure to hot and humid. Some EVA film makers to use EVA snail pattern attributed to recycled materials, with no use of EVA material back to promises no snail pattern phenomenon, in fact, this is the performance of fur and EVA resin only know very little understanding of the components and the blind structure made guarantee. Plastics Processing times will naturally lead to a gradual degradation of its own, but in the production of EVA film rarely have the possibility of repeated processing of EVA resin. Water permeability and the choice of formulation and processing lines and snails EVA film solar cell quality, backplane are, design and other aspects of the relationship between the components of both. For EVA film, in order to achieve the anti-snail pattern is more important is how to do their own resistance to hydrolysis.
PV power currently used anti-decay program components to ensure that after 85 degrees Celsius and 85% humidity of 96 hours of aging 1000V PV module power attenuation within 5%. Wei Hai excellent use of new materials AG EVA film anti-PID attenuation attenuation of less than 2% in a number of well-known components of plant trials. In the component surface water film in Japan Chemitox have anti-decay tests, new materials Wei Hai excellent anti-PID attenuation AG EVA film is to become the national assembly plant tested an important guarantee. Which means sea gifted Granville EVA film can in the harsh natural environment, protect PV modules have a longer life.
Plant life of 25 years, according to calculations, the components used in power and attenuation attenuation 0.8% compared to 5%, a difference of 9.4% ROI. Back to a point of view, now the best and worst of EVA material EVA material, the only difference between the cost per watt of 0.03 yuan, that generation made three days of gains can completely cover the costs. According to the British Wind & Sun Company 2.6KW power plant (the UK's first distributed power plants) and Hainan Jianfengling research station, power attenuation EVA yellowing and mostly caused by lightning patterns lead to hot spots, if high-quality EVA, component life completely can be more than 25 years to achieve a higher life. CQC technical engineer Zhang Xue said: Common Station power plant owners to invest considers component cost as low as possible, the actual components of such a concept does not take 25 years of life, and ROI power station, power plant investors should be concerned about the quality of the components, and packaging materials in the components in a very important position, especially EVA material, because the use of low-quality EVA could lead to large-scale outbreaks of lightning power plants and power lines attenuation as domestic installed capacity to grow, more and more prominent. Owners PV power plant investment, the choice of materials for EVA also need to be cautious.
I believe that despite the low quality components to reduce the cost per watt of installed capacity, but significantly reduces the life of the power station, leading to power plant does not meet lifetime decay occurs, even ahead of power plant scrapped. Investors should ignore the power plant construction cost per watt, and then focus on the cost of electricity.
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