Technology adaptabilityRegarding BC technology, a new entrant following TOPCon and PERC, its adaptability to the existing PV ecosystem, including both upstream and downstream components, will play a crucial role in a successful technology transition, says Xu. Providing a brief overview of the PV ecosystem during the transition from PERC to TOPCon, Xu highlighted the major challenges, opportunities, and legacies that the industry encountered. Key challenges included the shift from p-type to n-type, the need for higher-purity polysilicon, silicon wafers with lower oxygen impurity (Oi) content – down to 12 ppma – the increase in minority carrier lifetime (MCLT) from 70 µs to 1 ms, the adjustment of resistivity range from 0.3-2.1 ohm·cm to 0.7-1.4 ohm·cm, and the reduction of wafer thickness to 125 µm.Although TOPCon technology inherits the cell process flow and is largely compatible with tools used in PERC cell and module lines, several new process tools were required, including boron diffusion, SiOx+poly-Si deposition, laser for boron SE or LECO, as well as new metallization paste, encapsulant, and edge passivation. Xu also noted that TOPCon inherited established markets from PERC, such as utility, residential, and commercial applications.In contrast, TBC technology inherited several features from the TOPCon ecosystem, including the same-grade n-type poly-Si, the same or lower requirements for Oi content (no boron diffusion), and identical MCLT ranges. However, the flexibility to use higher wafer resistivity, compared to TOPCon’s range of 0.7-1.4 ohm·cm, presents an opportunity for ingot makers, Xu noted. While the cell fabrication process steps offer multiple inheritances, including tool compatibility, a lower budget for thermal processes, encapsulant, and edge passivation, there is a need for 2 additional process steps: patterning/cleaning and an extra poly-Si deposition. Additionally, metallization paste, customized for contacting p-poly-Si, is required. On top of it, the BC transition must address the global economic landscape of oversupply and the industry's cash loss challenges.The company expects to launch the next-generation Maxeon 8 series IBC module, which will feature more than 25% efficiency, in 2025.
