Solar glass is a core material in the photovoltaic industry, and its production process directly impacts the photovoltaic conversion efficiency and service life of photovoltaic modules. Its production process integrates traditional glass manufacturing techniques with photovoltaic functionalization processes and consists of four key steps: raw material preparation, melt forming, tempering, and functional coating.
Raw material preparation is the foundational stage. Production uses high-purity quartz sand as the primary raw material, supplemented by fluxing agents such as soda ash and limestone, and a small amount of alumina or borate to enhance the glass's mechanical strength and weather resistance. The raw materials must be precisely proportioned and mixed to ensure a uniform chemical composition, with an error within 0.1%, providing a stable foundation for subsequent melting.
Melting forms the raw materials through high temperatures to convert them into molten glass. The mixture is heated in a furnace above 1500°C. After thorough clarification and homogenization, it forms a highly transparent, bubble- and streak-free molten glass. Modern processes often utilize oxyfuel combustion to reduce nitrogen oxide emissions and improve energy efficiency. Molten glass is processed through either the float or rolling process to form uniformly thick glass sheets. The rolling process is more suitable for surface texturing to reduce light reflection.
Tempering significantly enhances the strength and safety of glass. After preheating the formed glass sheets to over 600°C, they are rapidly cooled to form a surface compressive stress layer, increasing impact resistance by more than five times while also meeting the wind and earthquake resistance requirements of photovoltaic modules.
Functional coating is a key step in imparting photovoltaic properties to glass. Anti-reflective coatings (such as silicon nitride) are applied to the glass surface using magnetron sputtering or chemical vapor deposition (CVD) techniques, increasing visible light transmittance to over 93% while reducing ultraviolet and infrared transmission and protecting the cells from degradation. Some high-end products also incorporate conductive coatings to support building-integrated photovoltaic (BIPV) applications.
Finally, after cutting, edge grinding, and sorting, solar glass undergoes optical performance, mechanical strength, and weather resistance testing to ensure compliance with industry standards. Technological iterations in this process continue to drive down the cost of photovoltaic power generation and are a key support for the development of clean energy.
