In the n-type circuit, DAS Solar is recognized as a black horse. It took less than five years for a new product to emerge from its initial appearance and become one of the top 10 global module shipments. During this period, DAS Solar focused on TOPCon cell technology innovation and fully promoted industrial development. At the beginning of 2022, Dr. Song Dengyuan, a veteran and leader of n-type technology in the solar industry, joined a new energy company and led a new energy TOPCon cell continuous technology iteration to stage 3.0, with an average conversion efficiency of 25.2%.
In 2023, DAS Solar has set a new goal – the cell conversion efficiency of TOPCon 4.0 will exceed 26%, and its TOPCon cell module capacity will reach 30 GW by the end of the year.
As a leading figure in the industry’s n-type high-efficiency cell technology, Song has made significant contributions to the industrialization of n-type cell technology in China. Tracing the history of the development of n-type technology, Yingli Solar first conducted research and development of n-type cells in 2009. At that time, Yingli’s team led by Song joined hands with the Energy Research Centre of the Netherlands (ECN) to develop high-efficiency n-type silicon bifacial PERT cell technology, and the project was named “Panda”. In 2010, the cell conversion efficiency of Yingli’s Panda reached 18.5%, demonstrating the high-efficiency advantages of n-type cells to the industry.
In 2013, German Fraunhofer ISE first proposed the concept of tunneling oxide passivation contact (TOPCon) cell technology, but at that time, the industry chain ecology was not yet mature. At the beginning of 2022, Song joined DAS Solar and served as the company’s Chief Technology Officer, fully responsible for the company’s research and development work as well as the technical research and development of n-type high-efficiency cells and modules. Under the leadership of Song, a new company successfully developed TOPCon 3.0 technology, further improving the average conversion efficiency of TOPCon cells in mass production to over 25.2%.
By the end of the TOPCon 3.0, the average conversion efficiency of the cell has increased from 24.6% in phase 2.0 to 25.2%, with a maximum efficiency of 25.8%. “TOPCon3.0 is a milestone in the entire TOPCon innovation series and serves as a connecting link between the preceding and the following. We have successfully developed the industrialization technology of high energy laser i-SE (industry selected emitter) with independent intellectual property rights, effectively reducing the recombination of photogenerated carriers on the front surface and improving the utilization rate of short wavelength spectroscopy; while the back side is ultra-thin ut-polySi (Ultrathin Poly Si). The technology can effectively reduce the parasitic absorption of the long wavelength spectrum by the back polysilicon layer, significantly improving the utilization rate of the long wavelength spectrum. The perfect combination of these two technologies overcomes the bottleneck in improving the efficiency of TOPCon solar cells, resulting in a 40.6% and 15.3% increase in the quantum efficiency of short wavelength and long wavelength light, respectively, with an average increase in cell efficiency of more than 25.2%,” said Song.
According to DAS Solar’s TOPCon cell technology roadmap, the average conversion efficiency of its TOPCon 4.0 cell will exceed 26% by the end of 2023, which is encouraging news for the industry. Every 1% increase in cell efficiency will increase the power density of the module by 5%, and the system end will bring a gain of 7%-9%.
Speaking of the technical direction of achieving a breakthrough in the average conversion efficiency of TOPCon 4.0 cells of 26%, Song introduced, “TOPCon cell technology is by far the most perfect passivation contact cell structure for crystalline silicon cells, with a cell efficiency limit of 28.7%, which is closest to the limit efficiency of 29.4% for crystalline silicon solar cells. In fact, there is still a lot of room for improvement. To achieve efficiency of 26%, the direction is to further develop TOPCon 4.0 technology based on high carrier selection materials and cell structure, which will completely overturn the current market pattern of crystalline silicon cell products.”
According to InfoLink’s statistics, by the end of 2022, the landing capacity of TOPCon and HJT cells had reached 81 GW and 13 GW respectively, and the module shipments had reached 16 GW and 3 GW respectively.
By the end of this year, the silicon cost of TOPCon cells will be basically equal to that of PERC. From the perspective of the non silicon cost of the cell end, TOPCon is about RMB 0.17-0.19 yuan/W, and PERC is about RMB 0.14 yuan/W. Seen from power station system gain, TOPCon has higher power generation per watt, lower system costs, and more obvious overall cost performance advantages.
Since 2022, DAS Solar has won a bid with a scale of 10 GW. To ensure the supply of n-type high-efficiency products, DAS Solar is also steadily expanding, and it is expected to achieve more than 30 GW of cells and modules by the end of 2023.
According to Song’s prediction, combined with HJT and XBC, it is expected that by 2025, the market share of n-type products will exceed that of p-type products and become the mainstream.