About Double Glass Photovoltaic Module Knowledge
Recently, some domestic mainstream manufacturers have introduced dual glass components. Double glass components are like rockets. Their heat is high and they suddenly start to fire. What kind of product is it?
The double-glass photovoltaic module refers to a double-glazed solar PV module formed by two glass sheets and a solar cell sheet, and the battery sheets are connected together by a wire string and a parallel connection to a lead end. Due to the use of standard photovoltaic glass before and after, the early double glass units were heavy and inconvenient to handle. At the same time, because of the inability to solve the power loss due to light leakage between the cells, no mass production has been established.
Since 2013, with the photovoltaic power stations that have been previously invested in domestic and overseas power generation and have been operating for a period of time, the quality problems of power plants at home and abroad have appeared on a large scale. Many power stations have experienced quality problems such as snail lines and PID decay. This problem has triggered a great concern at home and abroad on the quality of power stations. Due to the short lifespan and poor weatherability of organic materials, the quality of EVA films and backsheets in photovoltaic modules has begun to receive high attention. Some domestic power stations have caused large-scale snail problems in 70% of components due to the use of inferior EVA films, and some power plants have found up to 60% attenuation in one year of operation.
In addition to the brutal construction, these problems are often closely related to the rapid degradation of poor EVA resin through water vapor penetrating the back sheet. EVA resin begins to decompose when it encounters water, and its decomposition product contains acetic acid and acetic acid to corrode the silver grid line and the splicing zone on the photovoltaic cell, so that the power generation efficiency of the module decreases year by year. Photovoltaic projects in areas with near-water photovoltaic power generation, such as fish and fish complementing, beach power stations, agricultural greenhouses, and areas with large amounts of water in the morning and evening, quickly became high-risk projects. Since the current plant owner calculates the investment rate of return on a per-kilowatt basis, the long-term reliability and post-resistance of components have become the first considerations for PV module manufacturers.
The advantages of double glass components provide the best solution for high quality photovoltaic power plants.
1) With a higher life cycle power generation, 21% higher than normal components.
2) The general component warranty is 25 years and the double glass assembly is 30 years.
3) The attenuation of conventional components is about 0.7%, and that of double glass components is 0.5%.
4) The water permeability of the glass is almost zero, and there is no need to consider the problem of water vapor intrusion into the module to induce hydrolysis of the EVA film. The back plate of the traditional crystalline silicon solar module has a certain water permeability. The water vapor passing through the back plate causes the poor quality EVA resin to quickly resolve the acetic acid, resulting in electrochemical corrosion inside the module, increasing the occurrence of PID decay and snail appearance. The probability. It is especially suitable for photovoltaic power stations in the seaside, waterside and high humidity areas.
5) The glass is an inorganic silica, which is the same kind of material as the everywhere sand, and has superior weathering resistance and corrosion resistance to any known plastic. Ultraviolet light, oxygen, and moisture cause the backsheet to gradually degrade, and the surface is chalked and broken. The use of glass solves the problem of weatherability of the components once and for all, and it also easily puts an end to the more weather-resistant disputes of PVF and PVDF, not to mention the poor weatherability, poor water repellency of PET backings, coated backplanes, and Other low-end backplanes. . This feature makes the double glass module suitable for photovoltaic power plants in areas with more acid rain or salt spray.
6) The wear resistance of the glass is very good, and it also solves the problem of sand resistance of the module in the field. In areas with large winds and sand, the advantages of double-glass components are obvious.
7) The double glass assembly does not require an aluminum frame unless it has a large amount of dew on the glass surface. Without an aluminum frame, the electric field causing PID cannot be established, which greatly reduces the possibility of PID attenuation.
8) The insulation of the glass is better than that of the back plate, which enables the double glass block to meet a higher system voltage, so as to save the system cost of the entire power plant.
9) The fire rating of double glass components is upgraded from Class C to Class A of common crystalline silicon components, making it more suitable for use in residential areas, chemical plants and other areas that need to avoid potential fire hazards.
Why is a double glass assembly not used on a large scale in photovoltaic power plants?
Although the double glass component has so many advantages, it has not been used on a large scale in photovoltaic power plants. One important reason is that it is a transparent EVA film before and after its use, resulting in a large loss of power. Because there is no white backplane to reflect the light leakage between the cells back into the assembly, the module has at least 2% more power loss. "Using white EVA as the backside encapsulation material", a simple way to see the test, has plagued the assembly plant for many years.
Double-glass components currently have two options for sealing and non-sealing. An important reason why components are manufactured using unsealed solutions is that vapor erosion of the EVA film seems to be only about 0.5 to 1 cm deep. The actual 1000-3000 hours of hygrothermal aging test also seems to verify this statement. However, the water vapor transmission rate of EVA film is as high as 20-30 g/m2. Days, this design plan should still be a great risk. A more reasonable solution is to install butyl tape around the double glass assembly to isolate the EVA film from water vapor and oxygen. Another problem that the double glass assembly urgently needs to answer is to determine how much the wind pressure affects it. Due to the loss of the stereotyped effect of the four-sided aluminum frame, whether the double-glazed glass under wind pressure can avoid damage caused by wind pressure to the module also requires certain data support.
Due to the elimination of the use of aluminum frames for the double glass assembly, the cost savings allow the entire assembly to provide sufficient space for the use of high-quality EVA film, butyl tape, and junction box under the premise of cost reduction. This gives the double glass assembly the possibility of being a component that can be used for 30 years, 40 years or even 50 years. At the same time, high-quality white EVA makes the PV modules more efficient, even if the power generation efficiency is improved. All of these have led to a significant drop in the cost of electricity for photovoltaic modules, making investment in photovoltaic power plants a truly life-long project. Since glass itself is a commonly used building material, the use of a double-glass assembly is naturally ready for the large-scale use of double-glass PV modules in buildings in the future.
Hebei Giant Metal Technology Co., Ltd. , https://www.wiremesh.pl