LONGi’s HPBC Inching Closer To 29.4% Theoretical Cell Efficiency Limit

LONGi’s Product Marketing Manager Dante Zeng, while speaking on day 4 of the 4-day TaiyangNews High Efficiency Solar Technologies 2024 Conference called his company a pioneer of the BC technology having introduced it to the market for the first time in 2022. The manufacturer made the technology its own with the hybrid passivation back contact (HPBC) technology.  

Having achieved 25.5% cell efficiency with HPBC technology, LONGi reported 26.6% efficiency for HPBC 2.0 generation in 2024 using its TaiRay wafer and incorporating a zero busbar (0BB) structure, among other improvements. It is now inching closer towards the theoretical limit of 29.4% cell efficiency in mass production, pointed out Zeng.   

Even though most tier I manufacturers prefer TOPCon or work on HJT, LONGi chose the BC route due to its potential for high efficiency, pleasant aesthetics, and reliability, explained Zeng. It has the highest theoretical cell efficiency among all silicon technologies at 29.1%.  

A soft breakdown design structure under HPBC 2.0 reduces shading power loss, allowing blocked current to bypass and prevent localized overheating. At the same time, shared Zeng, its high-doped, low resistance self-developed bipolar hybrid passivation contact layer improves overall cell performance.  

Compared to a TOPCon structure, LONGi’s HPBC 2.0 based Hi-MO X10 modules get up to a 2.18% power boost, he added.   

Going forward, LONGi’s cell technology roadmap shows it continuing with the BC platform, but exploring the HBC or heterojunction+back contact route, aiming for a mass efficiency of 27% in 2026. It has a pilot line for HBC, and also an R&D line for tandem.  

For more presentation videos and conference summaries for all 4 days of the TaiyangNews High Efficiency Solar Technologies 2024 Conference, click here for days 1 and 2, and here for days 3 and 4.