光伏发电技术“十四五”科技发展展望

光伏发电技术发展现状与趋势

针对晶硅光伏组件寿命期后大规模退役问题，开展光伏组件环保处理和回收的关键技术及装备研究与示范试验，实现主要高价值组成材料的可再利用。针对目前行业各主流产品类型，开发基于物理法和化学法的低成本绿色拆解技术，掌握高价值组分高效环保分离的技术与装备；开发新型材料及新结构组件的环保处理技术和实验平台；研究组件低损拆解及高价值组分材料高效分离等关键设备，实现退役光伏组件中银、铜等高价值组分的高效回收和再利用。

In recent years, driven by technological progress, China's photovoltaic power generation industry has achieved rapid development, with the industrial scale and technological level reaching the world's leading level. Looking forward to the "14th Five-year plan" period, careful planning, advance layout, strengthen photovoltaic technology innovation and industrial upgrading, is to enhance the core source of power, promote high-quality, low-cost, large-scale development of photovoltaic power generation is an important guarantee.
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Development status and trend of photovoltaic power generation technology

(I) The development status of photovoltaic power generation technology in the world

Vigorously developing renewable energy has become the leading direction and concerted action of the global energy revolution and climate change. In recent years, photovoltaic power generation as an important renewable energy generation technology has achieved rapid development, in many countries has become a clean, low-carbon and price competitive energy form. In 2020, 127 million kw of new photovoltaic power generation will be installed globally, bringing the total installed capacity to 707 million kW.
Crystalline silicon cell is still the mainstream technology of photovoltaic cell industrialization, and the development of new cells is rapid. Photovoltaic cells, as the core components of the photovoltaic industry, can be divided into crystalline silicon cells, thin film cells, perovskite cells, organic cells and so on according to different processes and raw materials. Among them, crystalline silicon cells occupy the main body of large-scale production and application of photovoltaic cells due to their advantages of high conversion efficiency, rich source of raw materials, non-toxic and harmless. In recent years, the wide application of PERC (emitter passivation and back contact) technology has further promoted the improvement of conversion efficiency of crystalline silicon cells. On the other hand, new cells represented by perovskite cells have become a research hotspot worldwide, with rapid improvement in conversion efficiency. The highest conversion efficiency in the laboratory is close to crystal silicon cells, and the industrialization process is gradually advancing, but it still faces challenges in large-area application and device stability.

The refinement level of photovoltaic system has been continuously improved, and the application mode has been diversified. The number of photovoltaic system sub-lineup keeps increasing, the application proportion of 1500 VOLT photovoltaic system has gradually exceeded 1000 volt system, the safety and reliability standards of grid-connected system are constantly improved, and the power generation capacity and power quality of photovoltaic power station are constantly improved. The scale of composite applications such as "PHOTOVOLTAIC + agriculture", "photovoltaic + animal husbandry", "photovoltaic + construction" and "photovoltaic + fishery" continues to expand. The in-depth integration of photovoltaic power generation and power grid, such as microgrid and smart grid, has gradually become a new form of business in the power industry.

(ii) Development trend of photovoltaic power generation technology in the world

Countries around the world continue to deepen the layout of photovoltaic power industry chain innovation, as a major strategic measure to promote the development of emerging industries, through the comprehensive layout of advanced materials, manufacturing and system application of research and development to achieve cost reduction and competitiveness.
Photovoltaic core devices are developing towards high efficiency, low energy consumption and low cost. Crystalline silicon cells have built a complete whole industry chain, and will continue to occupy the main share of photovoltaic cell production, and will further develop towards higher conversion efficiency, less raw material consumption, lower energy consumption and lower manufacturing cost in the future. Perovskite, laminated battery as an important development direction of future photovoltaic battery technology, in this respect in every country in the world the key input, to improve the device performance and stability, and promote the industrialization of layout, after solve the problem of large area, stability, etc, perovskite battery is expected to change the industry pattern of photovoltaic application market.
Photovoltaic applications are developing towards multi-use scenarios. Countries around the world, combined with their own actual situation, actively promote the development of photovoltaic building integration, floating photovoltaic, photovoltaic + agriculture, photovoltaic carport and other new application forms, and related specific product technology, joint operation control technology and so on become the focus of research.
(iii) Current situation of Photovoltaic power generation technology in China
During the 13th Five-Year Plan period, driven by the rapid expansion of the industrial scale, China's photovoltaic power generation technology has achieved rapid development, and the industrialization mass production technology of photovoltaic cells, modules and other key components has reached the world's leading level. The production equipment and technology are constantly upgraded, and the localization is basically realized. The complete set of photovoltaic power generation system technologies have been continuously optimized and improved, and the level of intelligence has been significantly improved.
Photovoltaic cell module technology is rapidly iterating, and its industrial manufacturing level is leading the world. By the end of the "13th Five-Year Plan", China's photovoltaic cell manufacturing process has basically realized the upgrading of the traditional "polycrystalline aluminum back field" technology to "single crystal PERC" technology, and the average conversion efficiency of the mainstream large-scale crystal silicon cell has increased from 18.5% to 22.8% at the beginning of the "13th Five-Year Plan", realizing a leapfrog development. The industrialization level of TOPCon (tunnel oxidation layer passivation contact), HJT (heterojunction), IBC (back electrode contact) and other new crystalline silicon high-efficiency battery and module technology has been continuously improved. The head enterprise has repeatedly refreshed the world record of industrialization production conversion efficiency, and has large-scale production capacity and strong international competitiveness. Perovskite and other new generation of high-efficiency battery technology keep pace with the world, research institutions have repeatedly created the world record of perovskite battery laboratory conversion efficiency, some enterprises have carried out industrial production research, and repeatedly refresh the industrial production module conversion efficiency record.
The level of photovoltaic power generation manufacturing equipment has been significantly improved, and basically localization has been realized. China's photovoltaic equipment has realized the development from low-end to high-end, the degree of product customization continues to improve, high productivity and efficient automation capacity continues to improve, automation, digitalization, networking degree to promote the photovoltaic manufacturing to photovoltaic intelligent manufacturing transformation. Polysilicon silicon chip, cell chip, component production equipment has basically realized localization.
Photovoltaic power generation system technology has been continuously optimized, and intelligent operation and maintenance has helped improve power generation capacity. A large number of new technologies have been applied to the overall design and system-level optimization of PHOTOVOLTAIC power stations. Photovoltaic support tracking system and 1500 volt voltage effectively improve the actual power generation capacity of photovoltaic power generation system; Intelligent robots, drones, big data, remote monitoring and advanced communication technologies have been used in the operation of power stations.
(4) Development trend of Photovoltaic power generation technology in China
As the world's largest photovoltaic power generation application market, China has become the incubator of all kinds of new photovoltaic cell technology industrialization transformation and application. In the future, China will continue to focus on the key development direction of international photovoltaic power generation technology and lead the continuous innovation and development of global photovoltaic power generation industrialization technology.
Photovoltaic cell efficiency has been further improved. Crystalline silicon cells will remain dominant for some time, and PERC technology will dominate. N-type crystalline silicon cells using TOPCon or HJT technology are expected to become the next mainstream photovoltaic cell technology after comprehensive consideration of efficiency, cost, scale and good market competitiveness. High-efficiency photovoltaic cells based on new material systems such as perovskite cells and laminated cells are the research hotspots, which are expected to bring a step improvement in the conversion efficiency of the next photovoltaic cell after the industrialization technology is gradually mature.
Photovoltaic modules go hand in hand with high efficiency and reliability. Component technologies such as half-chip technology, imbricated technology and multi-main grid will be further widely used, and double-sided components will gradually become the mainstream of the market to improve component efficiency and power generation capacity. New packaging technology and packaging materials further improve the reliability of components.
Photovoltaic power generation system intelligent, diversified development. The inverter will develop to the direction of high-power single machine, high-voltage access and intelligence, and constantly deepen the integration with energy storage technology, and improve the level of intelligent operation and maintenance technology. The application technology of photovoltaic building integration and other new scenarios is constantly improved to expand the development space of photovoltaic power generation.
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Development direction and goals of photovoltaic power generation technology in the 14th Five-Year Plan
It is predicted that in order to achieve the goal of carbon peak and carbon neutrality, by 2030, China's installed photovoltaic power generation needs to reach 900 ~1 billion kW; By 2060, it needs to reach 3 to 3.5 gigawatts. Photovoltaic power generation in the unprecedented development opportunities and space, but also facing many challenges, photovoltaic technology innovation will become a key factor to deal with these challenges.

We will strengthen technological innovation, increase the value of comprehensive land use, and promote large-scale development of photovoltaic energy. It is estimated that the potential of solar energy development in China can reach 100 billion kilowatts, but considering the ecological red line and basic farmland, about 44% of China's land area cannot be used for photovoltaic and other new energy projects. The National Forestry and Grassland Administration and other departments have increasingly standardized requirements for new energy development. Under the new situation, it is urgent to further improve photovoltaic power generation capacity per unit area, reduce the demand for construction land for photovoltaic power generation projects, and strengthen comprehensive land use to improve land use efficiency. On the one hand, through the application of new materials and new technologies, the conversion efficiency of photovoltaic cell modules is improved, and the power generation capacity of photovoltaic modules per unit area is improved. On the other hand, the design and construction level of photovoltaic power generation system is constantly optimized, application mode innovation is carried out, and intelligent management, operation and maintenance of photovoltaic power station life cycle is strengthened to improve the power generation efficiency of photovoltaic power station.

The grid-connected performance of photovoltaic power generation is further improved to meet the requirements of high permeability applications. With the continuous improvement of photovoltaic power penetration in the power grid, the power system will face challenges in security, stability, power quality, economy and other aspects. As an important part of the construction of a new power system with new energy as the main body, it will become an important research direction to improve the prediction accuracy of photovoltaic power generation power, improve the photovoltaic system active support and resistance to power system disturbance and other grid related performance.

The integration of distributed photovoltaic and other fields will become an important part of photovoltaic power generation in the future. While steadily promoting the construction of large-scale photovoltaic bases, new application forms such as the integration of photovoltaic buildings, photovoltaic and transportation, and the integrated development of new infrastructure have put forward new requirements on the performance of photovoltaic products and photovoltaic power generation system. It is necessary to combine specific application conditions to continuously promote the development of photovoltaic power generation related technologies.

Improve the whole life cycle of photovoltaic power generation green industry chain. With the rapid growth of photovoltaic power generation installed scale in China in recent years, the issue of photovoltaic module recycling at the end of life has been increasingly concerned. Combined with the growth of photovoltaic power generation scale in China, it is expected that China will usher in the first demand peak of photovoltaic module recycling around 2040. In the long run, under the requirement of carbon peak and carbon neutrality, it is urgent to improve the harmless recycling and treatment technology of photovoltaic modules due to expire, push it to industrialization, and complete the last link of the green industry chain of the whole life cycle of photovoltaic power generation.

Strong capacity to ensure the implementation of photovoltaic development goals. In 2020, China's photovoltaic module production capacity 244.3 million kw, the actual output of 124.6 million kW, about 60% of the modules sold overseas, "14th five-year" period still need to further improve the capacity of photovoltaic products guarantee. On the one hand, it is necessary to further develop the intelligent manufacturing technology of photovoltaic cells, modules, inverters and other core components, improve the level of intelligent production, improve production efficiency and production capacity; On the other hand, it is necessary to further carry out technological breakthroughs, break through the localization technology of a small number of key manufacturing equipment components as soon as possible, and eliminate potential bottlenecks in development.

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Development prospect of photovoltaic power generation technology in the 14th Five-Year Plan

Synthesis of carbon peak, carbon neutral situation needs analysis of the development of photovoltaic industry technology, during the period of "difference", photovoltaic power generation technology in China is expected to continue rapid development momentum, "much starker choices-and graver consequences-in" in the country as a whole under the guidance of development goals, focusing on the key problems existing in the industrial chain research and breakthrough, "fill the short board, long forging board", To continuously improve the technical level of China's photovoltaic power generation industry and help achieve the goal of carbon peak and carbon neutrality.

(1) Developing high-efficiency and low-cost photovoltaic cell technology

Build new formats of high-efficiency and low-cost crystalline silicon cells, further improve the conversion efficiency of crystalline silicon cells, promote the wide application of high-efficiency new technologies, and improve the power generation capacity per unit area of photovoltaic power generation system. One is the key for TOPCon, HJT, IBC new crystalline silicon cell, such as low cost and high quality manufacturing technology research and industrialization of key materials, development of high quality industrial production technology and equipment manufacturing technology, further improve the industrialization production efficiency and the battery conversion efficiency, reduce production costs, promote efficient crystal silicon scale applications, It includes the research of low-cost and efficient cleaning technology, high-quality passivation technology, low-cost metallization technology and so on. The second is to study the manufacturing technology of low-cost and high-quality silicon wafers. Focus on breakthroughs in low-cost and efficient silicon pellet preparation, continuous crystal drawing, n-type and gallium-doped P-type silicon rod preparation technology, strengthen support for large-scale development from the source of the industrial chain. At the same time, we will develop the large-size ultra-thin silicon wafer cutting technology, master the ultra-thin silicon wafer cutting process, complete the development of supporting equipment, related main and auxiliary materials and supporting technology research, achieve the stable cutting and output of large-size ultra-thin silicon wafer, and support the development of photovoltaic cells with low silicon cost.

(2) Strengthen the research on the preparation and industrial production technology of high-efficiency perovskite batteries

Closely follow the world's photovoltaic technology development hot spots, carry out new perovskite cell preparation and industrial production technology focus, promote the large-scale production of single-junction perovskite cell. At the same time, the efficient stacked cell process is developed to break through the efficiency limit of single junction cells and realize the step improvement of photovoltaic cell conversion efficiency. First, study the complete set of preparation technology of large-area high-efficiency, high-stability and environment-friendly perovskite battery, develop the cascade and packaging technology of high-reliability components, develop the mass production process equipment based on solution method and physical method, and realize the industrialized mass production of high-efficiency single-junction perovskite battery. The second is to carry out research on the preparation technology of high-efficiency laminated cells such as crystal silicon/perovskite and perovskite/perovskite, optimize the design of laminated structure and preparation process, greatly improve the power generation efficiency of photovoltaic cells, and gradually realize the industrial mass production capacity.
(3) Promote the grid-connected performance of photovoltaic power generation
Develop new type high efficient high-capacity photovoltaic (pv) grid technology research and demonstration test, the key technology breakthrough in medium voltage grid inverter, carry out under the condition of weak power grid coupling resonance mechanism and suppression strategies, active standby and energy storage unit with the combination of the optimal adaptive virtual synchronization technology, high power density, medium voltage power module optimization design and system integration empirical testing technology research, Ac direct - mounted medium - voltage grid-connected inverter is developed. To break the bottleneck of large photovoltaic efficient and stable DC convergence technology, carry out research on high-power and high-efficiency DC boost converter topology, self-discipline control technology, intelligent series/parallel control of multiple DC converters and multi-scene intelligent operation control technology, and develop high-power DC converters. Carry out research on key technologies such as transient steady-state characteristics and simulation between photovoltaic power generation and power system to improve grid-connected performance of photovoltaic power generation.
(4) Promoting the application of distributed technologies such as the integration of photovoltaic buildings
We will promote the "PHOTOVOLTAIC plus" and other distributed photovoltaic application technology innovation, expand the application of distributed photovoltaic, and boost the high proportion of photovoltaic power generation. Focus on the research on related technologies of photovoltaic roof, glass curtain wall and other integrated products of various forms of photovoltaic building, comprehensively consider the building structure, strength, fire prevention, safety performance and other factors to meet the needs of large-scale application. At the same time, we will carry out research on product modularization and lightweight technology, improve relevant technical standards and specifications, and promote the integration of photovoltaic buildings and large-scale and wide application of comprehensive utilization of photovoltaic power generation and other fields.
(5) Strengthening the localization of photovoltaic smart manufacturing and equipment
Build a smart photovoltaic production and manufacturing system, improve the production and manufacturing capacity, carry out key focused breakthroughs, make breakthroughs in the localization of key equipment and components, solve potential production technology bottlenecks, and ensure the supply of future photovoltaic core products. First, improve the production of polysilicon and other basic materials, the intelligent level of photovoltaic cell and component manufacturing, improve the supply capacity of intelligent photovoltaic terminal products; Second, independently research and develop core equipment for high-quality heterojunction batteries, break through manufacturing technologies such as molecular pumps, vacuum valves, power supplies, vacuum gauges and other vacuum equipment standards and performance testing equipment for high-quality manufacturing equipment; The third is to break through the large-scale application technology of domestic power modules, controller chips, digital signal processors and other key components for photovoltaic inverters; Fourth, master the manufacturing technology of key materials such as low-temperature silver paste and sputtering target materials for heterojunction photovoltaic cells.
(6) Developing photovoltaic module recovery, treatment and reuse technology
To solve the problem of large-scale decommissioning of crystalline silicon photovoltaic modules after their life, research and demonstration tests on key technologies and equipment for environmental protection treatment and recovery of photovoltaic modules will be carried out to realize the reuse of major high-value constituent materials. Develop low-cost green disassembly technology based on physical and chemical methods, and master the technology and equipment for high-value components separation with high efficiency and environmental protection, aiming at the current mainstream product types in the industry; Developing environmental protection treatment technology and experimental platform for new materials and new structural components; Research key equipment such as low-loss component disassembly and high-value material separation to realize efficient recovery and reuse of high-value components such as silver and copper in retired photovoltaic modules.