At the BC Deep Dive session during STC.I 2026, experts examined BC solar technology from cell and module perspectives
They discussed design, metallization challenges, process complexity, and integration into manufacturing lines
BC modules are already deployed at utility scale; these show promise for space applications, and could surpass front-contact technologies in efficiency
Back-contact (BC) solar technology is gaining attention globally. It is seen as a potential pathway to achieving higher efficiencies in single-junction silicon cells. At the Back Contact Deep Dive session during the TaiyangNews Solar Technology Conference India 2026 (STC.I 2026), speakers examined the technology from both cell and module perspectives.
They discussed its design, metallization challenges, process complexity, material requirements, and integration considerations. The session also assessed the technology’s potential and its relevance for future manufacturing in India.
Radovan Kopecek, Co-founder and Director of ISC Konstanz, highlighted the key factors shaping the adoption of BC. He noted that BC modules are already being deployed at utility scale and are expected to surpass front-contact technologies as efficiencies improve toward the practical limit of 26% for single-junction silicon modules.
Kopecek emphasized that the technology is not inherently complex and benefits from easier rear-side polysilicon application, simplified copper metallization, improved bifacial performance, and lower degradation. There are also ongoing R&D collaborations for space applications, including self-repairing BC cells for satellites.
He also highlighted key advantages of BC over TOPCon: cell and module efficiency, comparable bifaciality and COO, and a potential low LCOE of less than 1 ct/kWh. Kopecek noted that ISC's BC technology will not have any IP conflicts for manufacturing.
Kopecek also underscored the potential for local production in India using BC technology. In summary, he stressed that BC technology is poised to lead the next wave of solar efficiency gains, both on Earth and in space, while offering practical advantages in manufacturing and long-term module performance. Bifacial BC will dominate the market from 2029/2030 as its bifaciality will reach 80+%, said Kopecek.
His colleague from ISC Konstanz, Raphael Shanmugam, highlighted the technical advantages of BC gapless solar modules. He explained that BC technology moves all electrical contacts to the rear of the cell, allowing for fully black, unshaded front surfaces and overlapping cells to create gapless modules. This improves efficiency, reduces hotspots, and lowers cell stress, enhancing long-term reliability.
Adopted by leading manufacturers such as AIKO and LONGi, BC is already achieving top efficiencies in the market, and has strong prospects for widespread adoption, he pointed out.
Shanmugam shared that ISC Konstanz has developed full modules using copper metallization and is currently researching the lamination interconnection method. He said these can be integrated with existing module production lines.
Building on ISC Konstanz’s research in BC module integration, the session then explored how existing production lines can be upgraded to leverage cutting-edge BC and TOPCon technologies.
Jerry Liao, Chief Technology Officer (CTO) of Leadmicro, detailed the company’s approach to upgrading existing TOPCon solar production lines to BC technology. He highlighted multiple upgrade routes using PE, LP, and combined PE+LP processes and shared advancements in PECVD, ALD, EPD, and laser technologies.
Liao introduced a new PECVD method for TBC that deposits tunnel oxide and poly through PE, followed by an additional annealing step to enhance performance. He emphasized that turnkey TBC solutions from Leadmicro are expected to be available later this year.
He highlighted Leadmicro’s improvements in equipment design, including advanced loading methods, uniformity control, and no-cooling maintenance processes, all aimed at reducing costs, boosting throughput, and ensuring reliable mass production.
This article is part of TaiyangNews’ multi-part coverage of the TaiyangNews Solar Technology Conference India 2026 (STC.I 2026). Other sessions on Day 1 of STC.I 2026, apart from the inaugural session, included one on module manufacturing equipment, on module performance and reliability, on quality and sustainability, a policy panel, and an executive panel. Day 2 also covered a market overview.
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