"Longi Places Its Bet on Hi-Mo6 Panels with Back-Contact Solar Cell Technology"
Chinese solar module manufacturer Longi intends to incorporate its back-contact solar cell technology into the majority of its panel production. According to the company's chairman, Zhong Baoshen, who made the announcement during an investor meeting last week, Longi envisions that back-contact cells will become the dominant technology in crystalline silicon cells within the next five to six years. He emphasized the exceptional conversion efficiency of back-contact cells, characterizing it as the pinnacle of crystalline silicon technology, and suggested that the entire industry is poised to embrace this innovation.
Longi's ambitious goals include achieving a total solar cell production capacity of 110 GW by the conclusion of 2023, with 30 GW dedicated to TOPCon technology and 80 GW allocated for back-contact (BC) technology. Baoshen expressed a preference for back-contact cells over TOPCon devices, citing his belief that TOPCon cell technology is transitional and offers only marginal efficiency improvements when compared to previous advancements in PERC technology. Furthermore, BC technology can be seamlessly integrated with p-type wafers, and Longi boasts significant production capabilities in this area, providing the company with a competitive edge over the more commonly used interdigitated back-contact (IBC) technology.
Shen Wenzhong, the secretary general of the Shanghai Solar Energy Association and Director of the Solar Energy Research Institute at Shanghai Jiaotong University, explained that back-contact (BC) cell technology enhances the photoelectric conversion efficiency by relocating all the electrode grids from the front side to the back side of the cell. This relocation reduces the shading of the grids caused by sunlight. As a cell structure, BC technology offers the flexibility to be integrated with various cell technologies, allowing for the creation of back-contact-based solar cells.
In March, Longi introduced its own hybrid passivated back contact (HPBC) technology. Although the company has not provided a detailed explanation of HPBC, it is believed to be an extension of p-type (positively doped silicon) interdigitated back-contact (IBC) technology. HPBC combines the structural advantages of passivated emitter rear contact (PERC), tunnel oxide passivated contact (TOPCon), and IBC solar technologies. Longi's plan involves the development of "P-IBC" cells, utilizing its substantial production capacity for p-type wafers. This approach incorporates a silicon dioxide tunneling layer, polysilicon film, and upgraded laser equipment, as well as low-pressure chemical vapor deposition and coating-cleaning equipment, all of which are derived from PERC-process lines.