Among the many scientific research and innovation achievements of the photovoltaic industry, diamond wire cutting technology cannot be ignored. An electroplated diamond wire with the same thickness as hair and with diamond micropowder inlaid on the surface plays an important role in promoting the development of my country's photovoltaic industry.
The thickness and cutting loss of upstream silicon wafers in the photovoltaic industry are important factors that affect battery costs and even system power generation costs. The quality of silicon wafers produced by different cutting methods is not the same. The main cutting methods on the market include sand wire cutting and diamond wire cutting. The cutting principles of the two are different. The more traditional sand wire cutting is "rolling-embedded" cutting, similar to sawing; while diamond wire cutting is cutting processing, similar to grinding. Which cutting technology a company chooses is the key to its development.
According to Wang Yingge, assistant to the chairman and head of global market of Longji Leye Photovoltaic Technology Co., Ltd., diamond wire cutting is faster and more efficient than sand wire cutting, which can reduce the demand for silicon material per silicon wafer. To be thinner, thereby reducing the unit investment cost of silicon wafers. "If sand wire cutting is used, in addition to steel wire, auxiliary materials such as silicon carbide, polyethylene glycol, cutting fluid, etc. are also needed, and a large amount of mortar needs to be recycled. In contrast, diamond wire cutting can reduce the cost of auxiliary materials and also Environmental protection."
Although diamond wire cutting has obvious advantages, since the technology was only in the hands of a few Japanese manufacturers in the early days, it was not used in the photovoltaic industry at the beginning, and the entire domestic diamond wire industry chain was in a blank state, resulting in extremely high costs for adopting this technology. Therefore, in the early stage of the development of the photovoltaic industry, the more traditional sand wire cutting won at the price and became the "darling" of domestic silicon wafer manufacturers.
In Wang Yingge's memory, the diamond thread ten years ago is not too much to be called a luxury. "At that time, the price of diamond wire was more than one meter per one yuan, but now it is only about 0.1 yuan/meter, which is a drop of more than 10 times. This was unimaginable at the time."
Although the price of sand wire cutting and diamond wire cutting is very different, LONGi's founder and president Li Zhenguo and chairman Zhong Baoshen had keen insight at the time that there is limited room for future mortar cutting cost reduction, and diamond wire cutting is helping photovoltaic power generation to reduce costs and increase efficiency. , A tool for cheap Internet access, diamond wire cutting will become the mainstream technology of silicon wafer manufacturers.
Under this prediction, in order to reduce consumables and greatly reduce the defect rate of silicon wafers, at the end of 2012, LONGi made a major decision to fully convert the production line from sand wire cutting to diamond wire cutting.
In 2013, the transformation of LONGi's silicon wafer production line was first carried out in Xi'an Slicing Plant. Wang Yingge recalled that Longi's R&D model was not laboratory R&D, which greatly facilitated the transformation of production lines. For example, when the diamond wire is imported, it is first applied to some test models, and then copied to the production line after multiple modifications and successful running-in. After months of hard work and persistence, the diamond wire cutting transformation work is finally completed.