From December 9 to 10, the 13th BackContact Workshop, jointly organized by TNO (Netherlands Organization for Applied Scientific Research), Fraunhofer ISE (Fraunhofer Institute for Solar Energy Systems), ISFH (Institute for Solar Energy Research in Hamelin), ISC Konstanz (International Solar Energy Research Center Konstanz), and TU Delft (Delft University of Technology), was successfully held in Amsterdam, the Netherlands. Focusing on the latest R&D advancements and industrialization challenges of back-contact and passivation contact technologies—the core technologies for next-generation high-efficiency silicon-based solar cells—the event brought together top global research institutions, universities, and industry representatives. In-depth discussions were held on innovative processes, material systems, reliability enhancement, and cost reduction pathways for xBC cells, aiming to accelerate the PV industry's transition to a new phase of higher efficiency and lower costs. Li Zhonglan, Director of the Cell Development Department I of the PV Technology Center of Tongwei Co., Ltd., was invited to attend and deliver a keynote speech. She also participated in a panel discussion on BC technology R&D hotspots alongside leading R&D heads from Maxeon, Aiko European Research Institute, FuturaSun, and Kalyon PV.

Keynote Speech by Director Li Zhonglan from the PV Technology Center of Tongwei Co., Ltd.

Director Li Zhonglan delivered a keynote speech titled TOPCon Convert to TBC - The Tongwei Way, systematically introducing Tongwei's latest advancements in the field of xBC cell technology, with a focus on analyzing the innovative integration path of TBC technology with PECVD polysilicon processes and its industrialization potential.

"The transition from TOPCon to TBC is not merely a simple process overlay but a comprehensive upgrade of platform-based technology," stated Director Li Zhonglan. She emphasized that Tongwei has completed the development of TBC cells, single and double-glass modules, and high-density packaged TBC modules, achieving industry-leading standards. Tongwei has led the industry's transition to half-cell manufacturing for BC cells by commissioning its first BC half-cell finished product line in April 2024, a project initially planned in late 2023. Simultaneously, Tongwei becomes the first in the industry to publicly achieve PE-poly TBC cell technology.

Tongwei is also the first to propose applying PECVD Npoly-Si technology to TBC cells, while overcoming a series of challenges such as warping, passivation, and process integration. This technology provides a clear path for the company's future capacity upgrades. Moreover, the PECVD solution offers about 2% higher mass production yield compared to traditional LPCVD, while also demonstrating greater advantages in polysilicon layer thinning and module bifaciality.

Looking ahead, Tongwei will continue to deepen the research and development of BC technology, promote the upgrade and large-scale application of TBC technology, and simultaneously advance the integration of "multi-slicing + high-density packaging" with "perovskite/silicon tandem" technologies. Leveraging Tongwei Global Innovation R&D Center, the company will conduct comprehensive R&D on mainstream technology solutions such as TOPCon, BC, and HJT, building a multi-level and forward-looking technology matrix to create greater value for global customers and lead the sustained development of the PV industry in the new technological era.