Recently, the 3rd Photovoltaic New Materials (Encapsulant Film) Technology Innovation Forum was held in Shanghai. The forum featured in-depth discussions and exchanges on key topics, including encapsulant film technology innovation for N-type and perovskite solar cells, efforts to advance the localization of POE materials and restructure supply chains to enhance security, and the development of more efficient and intelligent manufacturing processes for PV encapsulant films. Guo Yiwei, Component R&D Manager at the Photovoltaic Technology Center of Tongwei Co., Ltd., was invited to attend and deliver a keynote presentation, systematically showcasing Tongwei’s latest R&D progress and mass-production practices in encapsulation materials for N-type TOPCon modules.

At the forum

In his keynote presentation, “Research on Design Optimization of High-Efficiency TOPCon Encapsulation Materials,” Guo noted that with the implementation of the national standard GB 47834-2026, *Minimum Allowable Values of Energy Efficiency and Energy Efficiency Grades for Crystalline Silicon Photovoltaic Modules and Inverters*, the PV module industry has officially entered an era of high energy efficiency. Encapsulation materials are no longer expected to serve merely as basic protective layers; instead, they require more advanced functional design across multiple dimensions, including optical utilization, process compatibility, weather resistance and reliability, and application-specific adaptability.

Guo Yiwei, Component R&D Manager at the Photovoltaic Technology Center of Tongwei Co., Ltd., delivering his keynote presentation

To address the new manufacturing challenges posed by multi-cut module structures, Tongwei has achieved effective breakthroughs through innovative encapsulation material design.

From an optical perspective, Tongwei has optimized the chemical grafting ratio and crystallinity of encapsulant film resins to improve optical compatibility between the films and other module encapsulation materials. This enhances the module’s optical gain and further increases output power.

To mitigate ultraviolet-induced degradation, Tongwei has developed an innovative UVID encapsulant film. Through cutoff-wavelength design and research into the mechanisms of yellowing under damp-heat conditions, the company has precisely balanced ultraviolet absorption with long-term weather resistance, providing a reliable solution for applications exposed to intense ultraviolet radiation.

In addition, to accommodate new processes such as ribbon folding, post-soldering, and ultra-high-screen butyl rubber technology, Tongwei has optimized the crosslinking rates and flow properties of multiple material layers. These improvements have effectively reduced defects such as bubbles formed during lamination, helping ensure the yield and reliability of high-efficiency modules.

As technologies such as heterojunction (HJT), back-contact (BC), and perovskite tandem cells continue to evolve, and applications expand into areas such as space photovoltaics and building-integrated photovoltaics, encapsulation materials will need to offer a more diverse range of functions. These include low-temperature, fast-crosslinking POE, flame retardancy, directional light conversion, and enhanced resistance to hot spots. Meeting these requirements will call for deeper collaboration between encapsulant film suppliers and module manufacturers, beginning at the initial material design stage.

This presentation demonstrated Tongwei’s technical expertise in leveraging incremental innovations in materials to improve module power output and reliability. As a vertically integrated photovoltaic company, Tongwei will continue to advance collaborative R&D across solar cells, modules, and encapsulation materials, providing systematic solutions to support the industry’s transition toward higher energy efficiency and contributing to the global development of clean energy.