On February 3, the inaugural Space-Based Solar Power Investors Forum, co-hosted by SOLARZOOM and Western Securities, was held in Shanghai. The forum focused on the commercialization path of space-based photovoltaic (PV) technology, bringing together representatives from the aerospace industry, investment institutions, and leading PV enterprises to explore the new frontier of space-based energy. Dr. Long Wei, Director of Tongwei Co., Ltd.'s PV Technology Center, was invited to attend and deliver a keynote speech titled "Tongwei's HJT Development Progress and Considerations for Space Applications".

Technological Breakthrough

HJT Emerges as the Optimal Solution for the Space Environment

With the accelerated development of sectors like commercial aerospace and space-based AI computing, space-based solar power has become a new strategic high ground in the global energy landscape. The space environment imposes extreme requirements on PV technology regarding lightweight design, high efficiency, and radiation resistance. Crystalline silicon materials, leveraging their natural advantages of abundant reserves and low cost, combined with the inherent benefits of Heterojunction (HJT) technology—such as short minority carrier collection paths and strong adaptability to ultra-thin wafers—have demonstrated exceptional performance in the harsh conditions of space via the p-type HJT + copper plating technical route. Research confirms that this structure exhibits outstanding performance in metrics like radiation resistance and tolerance to extreme temperature differentials (-170°C to +150°C). Notably, gallium-doped p-type silicon wafers with a resistivity of 15 Ω·cm show optimal radiation resistance, laying the foundation for the lightweight design and high reliability of space-based PV modules.

Keynote speech by Dr. Long Wei, Director of the PV Technology Center of Tongwei Co., Ltd.

Tongwei Practice

Technological Accumulation from Terrestrial to Space

Since initiating HJT R&D in 2018, Tongwei has achieved breakthroughs in core technologies like bifacial microcrystalline processing, silver-coated copper, and copper interconnect, reducing silver consumption to below 4mg/W and setting new HJT module power records 11 times. Particularly noteworthy, Tongwei's research achievement in 55μm ultra-thin HJT cells was featured on the cover of Nature, marking the company's global leadership in ultra-thin cell technology. Furthermore, Tongwei has established the industry's first 5MW perovskite-crystalline silicon tandem cell pilot line, initiating the exploration of tandem cell technology with over 30% efficiency for space applications.

Keynote speech

Space Prospects

GW-Scale Market Poised for Take-off

The current annual demand for space-based PV is approximately 15-20MW. With the increasing power of low-earth orbit satellites (evolving from 5kW towards 100kW) and the growth in launch volume, the medium-to-long-term market scale is expected to expand to the GW level. Dr. Long Wei also emphasized the need for a rational view of the unique space environment—UV radiation intensity under AM0 spectrum is over 1,200% higher than on the ground, and the temperature range spans from -170°C to +150°C, necessitating the establishment of dedicated reliability standards.

Industrial Empowerment

Technology-Driven Green Transformation for Aerospace

As a global PV leader featured in the Fortune Global 500 list for three consecutive years, Tongwei provides high-efficiency, low-cost energy solutions for commercial aerospace through forward-looking technological layout and mass-production capabilities. Moving forward, Tongwei will continue to deepen HJT technology iteration and research on space adaptability, supporting China's aerospace industry in transitioning towards a "low-cost, high-reliability" new energy era. Simultaneously, leveraging its collaborative innovation system encompassing "equipment-materials-processes," Tongwei will accelerate the journey of space-based PV technology from the laboratory to orbit, injecting green momentum into humanity's exploration of space.