What is the difference between single crystal and polycrystalline photovoltaic modules? Which is goo

       Photovoltaic modules ( also known as solar panels and photovoltaic panels ) mainly include polycrystalline modules, polycrystalline modules and thin film modules. What is the difference between single crystal and polycrystalline components? Which is good?

Solar power generation equipment

       There are historical reasons why the market share of single crystal components is smaller than that of polycrystalline components: the single crystal production process is more complex and the cost is higher than that of polycrystalline components. At the beginning of the rapid development of photovoltaic industry, the production capacity was king, and the intensive single crystal production capacity could not meet the market demand in terms of expansion speed. From 2005 to 2010, polycrystalline battery technology rapidly expanded its share based on relatively low cost, thus becoming dominant.

       However, single crystals have excellent properties. More than 30 years of application practice have proved the reliability of the single crystal technology route. In 1982, Europe's first online photovoltaic system was built in Switzerland, using a single crystal system. The single crystal system was also used in some domestic power stations in the 1980s. The data show that the total attenuation rate of Ningbo's single crystal photovoltaic system built in 1994 is only 3.1 % in 21 years, while the average annual attenuation rate of the single crystal roof photovoltaic system built in Munich, Germany, in 1997 is 0.4 %, which is obviously better than that of the polycrystalline photovoltaic power station.

       According to industry sources, the crystal arrangement of polycrystalline materials is irregular and the power station is prone to crack during the long-term alternation of high temperature and low temperature. The single crystal structure has better mechanical properties than polycrystals and better anti - cryption. Taken together, the unit power generation of single crystals is about 5 % higher than that of polycrystals.

       The advantages of single crystal power generation are due to its low operating temperature, weak light response, low line loss and low attenuation. At high temperature, the temperature difference of a single polycrystalline component is 3 - 5 degrees Celsius, and the power of the component will drop by 0.4 - 0.45 % every time the temperature rises. According to the long-term decay rate, the annual average decay rate of single crystal components is 0.55 % from the second year, while that of polycrystals is 0.73 %.

       In addition, the economy of single crystal can also be reflected in saving land, building materials, engineering and installation costs. It is estimated that the 50 MW single crystal photovoltaic project can save 100 mu of land, 160 tons of steel, 40 km of cables and 50 % of labor costs than the polycrystal photovoltaic project.

       In 2013, Panasonic HIT single crystal battery conversion efficiency reached 25.6 %, exceeding the maximum theoretical efficiency limit in photovoltaic industry. People again evaluated the performance and cost range of various technologies. From 2013 to 2015, the introduction of continuous rapid crystal pulling technology and diamond wire slicing technology reduced the cost gap between single crystal components and polycrystalline components to less than 3 %, and the unit investment cost of power stations using single crystal components and polycrystalline components was further reduced.

       With the breakthrough of technology and the reduction of the cost of single crystal products, their characteristic advantages will be better brought into play. The industry expects that by 2016, with the application of efficient technologies such as PERC, the cost of single crystal components and polycrystalline components will be basically the same. More optimistic forecasts say that by 2018, the market share of single crystal components and polycrystalline components is expected to reach 50 % each.

       On June 1, 2015, the State Energy Administration, the Ministry of Industry and Information Technology and the CNCA jointly issued the Opinions on Promoting the Application of Advanced Photovoltaic Technology Products and Industrial Upgrading. The State Energy Administration arranges a special market scale to implement the " Leader" plan every year, requiring the project to adopt advanced technology products. In 2015, the " leader" advanced technology products should reach the following targets: the photoelectric conversion efficiency of polysilicon battery module and monocrystalline silicon battery module should reach 16.5 % and 17 % respectively. According to this requirement, the polycrystalline components correspond to 270 watts ( 60 - 156 pieces ) and 325 watts ( 72 - 156 pieces ), respectively, and the single crystals are 275 watts ( 60 - 156 pieces ) and 330 watts ( 72 - 156 pieces ). This policy is considered by the industry, or will further activate the single crystal market.

       Market research shows that more than 80 % of single crystal products produced by domestic first-line manufacturers can meet the index requirements of the " leader" program. However, it is difficult for polycrystalline producers to meet the requirements of the " leader" program. Reaching the " leader" requirement is not only to say that the product meets the requirements of the procurement index, but also to verify whether it is produced with advanced technology and whether the product represents the advanced nature of the industry technology.

       For a long time, polycrystal has more cost advantages than single crystal. In the past, initial investment was more important in building photovoltaic power stations. Therefore, low-cost polycrystal products are naturally more favored. Now everyone's concept is also changing, paying more attention to the average cost of electricity throughout the life cycle of photovoltaic power stations. In this case, the performance advantages of single crystal will be more prominent.

       Considering the conversion efficiency and manufacturing cost of single crystals and polycrystals, at present, both single crystals and polycrystals have relatively mature technologies. Starting in 2016, the production cost of single crystal components will be almost the same as that of polycrystalline components. It is the same as that of the same enterprise that debated whether single crystal or polycrystalline silicon or thin film is good. It is not decided by which enterprise, but ultimately decided by the market, and it cannot be said who will replace whom.