Silicon wafer accounts for 30%-40% of the cost of a solar module. Larger wafer size increase the area exposed to light, increasing power and reducing cost. So that, since 2H-2018, the industry has continued to develop larger size wafers, leading to various specifications.
LONGi Solar has launched recently a press release stressesing the need for consistency in standards for PV wafers size. As the press release states, according to Professor Shen Wenzhong, Director, Solar Energy Research Institute of Shanghai Jiaotong University: “The 166 mm wafer has reached the allowable limit of production equipment which is difficult to overcome. This would be the upper limit of the standard for a considerable period.”
Li Zhenguo, President of LONGi Group considers that these different wafer sizes will lead to a mismatch in processes and standards in the supply chain, according to. “If manufacturers cannot reach an agreement on a size standard, it will restrict the development of the whole industry.” said.
Shen Wenzhong also said: “Existing crystal drawing and slicing equipment are compatible with 166 mm size silicon wafer. Production equipment for cell and module needs to be modified, though the costs are lower and easier to achieve. Calculated by “flux”, cell and module production line using 166 mm wafer will increase capacity by 13% as compared with the 156 mm size”.
The order books for LONGi’s Hi-MO4 modules using M6 monocrystalline silicon wafers, 166 mm, have exceeded 2 GW, so that large-scale production will commence the third quarter of 2019.
By the end of 2020, LONGi will upgrade its existing cell and module lines and transform them for production with 166 mm wafer. New lines – such as the 5 GW monocrystalline cell line in Yinchuan – will be designed for the 166 mm size from the start.
LONGi announced the price of its M6 monocrystalline silicon wafer in May-2019 at 3.47 RMB/piece, which is only a small 0.4 RMB premium compared to its M2 wafer. According to LONGi, the compatibility of wafer production lines with M6 would ensure large-scale supply in 2019, thereby reducing the price differential to less than 0.2 RMB.