Photovoltaic scientist sees Back Contact technology as the cell technology of the future


During the 6th China International PV Industry Conference (Chengdu, China, 13-16 November 2023), Dr Martin Green, Professor at the University of New South Wales, Australia, shared his view that IBC technology (Interdigitated Back Contact) will dominate the industry landscape. "I think everyone will eventually be manufacturing IBC cells." Although not specifying a time frame, his assessment is in line with earlier statements of LONGi's Chairman Baoshen Zhong, who emphasized the superiority and future viability of the technology over conventional technologies back in September. He said that Back Contact cells would become the most important technology in the PV sector in the next five to six years and redefine the industry landscape due to its characteristics of combining high efficiency with appealing aesthetics.

At the conference, Dr. Green gave further insights in a media interview and praised China's global leadership in solar technology and its ability to produce solar cells efficiently. 

LONGi Cell Manufacturing
LONGi Solar Cell Manufacturing

Technological breakthroughs need a well-funded R&D 

Baoshen Zhong, Chairman of LONGi, said that technological innovation would be the main driver for photovoltaic development. Over the past 15 years LONGi has spent over EUR 2.540 billion (CNY 20 billion)* in research and development which accounts for about 5 percent of its annual sales. LONGi’s R&D Technology Centre employs more than 5000 people.

LONGi's latest breakthrough for mass-market PV products is the company's proprietary HPBC (Hybrid Passivated Back Contact) solar cell, a new Back Contact technology that enables a free front side without shadowing metal contacts. This approach optimises the light absorption, resulting in enhanced conversion efficiency. After years of development by the LONGi science team, the technology was rolled out across LONGi's Hi-MO X6 series in November 2022.

The HPBC cell sets a new industry standard with a cell efficiency of over 25% in mass production, resulting in a significantly higher module output. The module efficiency is currently 23.3% in mass production and is continuously being improved.

Dr. Green sees Chinese development laboratories at the forefront of future developments 

LONGi recently announced another efficiency record of 33.9 % for crystalline silicon perovskite tandem cells, surpassing the theoretical efficiency limit of Shockley-Queisser (S-Q), which is 33.7 % for single-junction solar cells of all cell materials. 

Dr. Green commented: "China now holds the world record for the more innovative perovskite cells, meaning that the country’s laboratories not only lead in current mainstream technology, but are also well placed to be at the forefront of future developments." He further elaborated that improving cell efficiency would substantially be reducing the manufacturing costs, because that way more electricity could be produced per unit area from the cells, and cost reduction would be the best approach in the upcoming PV industry crisis. Baoshen Zhong stated earlier this year: “For the entire PV industry, achieving maximum efficiency at low cost through mass production and a high market acceptance is the key driver for future investment.” 

The PV industry crisis can be overcome by the strongest players  

Dr. Green anticipates that the price for solar modules would be dropping further, and he is hoping this will stimulate demand. During crisis, weaker players would be eliminated, and strong companies survive. This would lead to a consolidation in the industry. He anticipates that an increased demand in modules in the next 3 years, also as a result of low costs for modules, would help accelerating the replacement of the fossil fuel generation.   

In October 2023, LONGi received the AAA rating in the latest PV ModuleTech bankability report for the 15th consecutive quarter putting LONGi  among the strongest of players in the PV industry and attesting its financial stability.  

* Exchange rate: EUR 1 = 7.8771 CNY, 30th June 2023, People’s Bank of China 

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