TOPCon technology has higher theoretical efficiency potential at 28.7%, which is even higher than that of HJT's 27.5%. However, the best TOPCon efficiency reached so far has been by ISFH at 26.1%, still less than the best HJT cell efficiency of 26.63% by Kaneka. These two top figures were actually achieved by combining the IBC architecture with respective technologies. ISFH set its record by combining its proprietary POLO structure with IBC adapted to the p-type base wafer. For a double-sided contacted cell, Fraunhofer ISE announced a record 26% efficiency for its TOPCoRE cell, an architecture adopting rear junction architecture on the TOPCon structure (see TOPCon Rear Emitter Cell Attained 26% Efficiency).
The race among the mainstream PV manufacturers has actually been an interesting one, with a series of performance records announced since the end of last year. Trina Solar, one of the early adopters of the technology, is still holding the best performance figure 25.5%, but was also first among the top companies to held the world record efficiency of 24.58% from May 2019 till July 2020, to be surpassed by JinkoSolar's 24.79%. It didn't take long for JinkoSolar to break its own record, hitting 24.9% in the beginning of January 2021. LONGi, a strong proponent of p-type PERC, announced in April 2021 that it broke the 25% barrier by achieving 25.09% for its 242.77 cm2 TOPCon cell technology called HPC (see LONGi Reports 25.09% N-type TOPCon Cell Efficiency). In June, just about 2 months later, JinkoSolar regained the spot by announcing an efficiency of 25.25%. Close, but no cigar — LONGi announced the very next day that it had achieved 25.21%, falling short by a mere 0.04%, while the average pilot run efficiency is at 24.34%. Not just setting up the record, JinkoSolar has also increased its commercial activities with TOPCon, reaching 24.15% efficiency in mass production, as indicated at the TaiyangNews virtual conference on Very High Power Solar Modules. JA Solar is yet another mainstream top tier company that is also evaluating TOPCon. The company is currently in the pilot phase with an average efficiency of above 24%. However, very recently (after we published our TOPCon report), in late March 2022, Trina Solar announced its latest world record of 25.5%, which till date is the highest, and is attained on a G12 wafer format (see JinkoSolar: 24.9% Efficiency Record For TOPCon Solar Cell).
That said, Jolywood has been the leader when it comes to commercialization of TOPCon and perhaps the only company running a GW scale TOPCon production line (even though there are few other GW-level pilot lines). Jolywood started with n-type PERT technology and improved it from 21.5% to 22% between 2016 and 2018. In parallel, it started development activities for TOPCon in 2017 with an initial efficiency of 21.8%, which currently stands at 23.8% average in mass production. With its TOPCon 2.0 technology implemented in a pilot scale, Jolywood has already achieved 24.09% average efficiency with 97% yield, while the best R&D efficiency achieved is 24.5%. Dr Du Zheren, Cell R&D Director at Jolywood, on Day 3 of TaiyangNews Virtual Conference on High Efficiency Solar Technologies 2021 said that he aims to further improve the efficiency level of their TOPCon technology (see The Progress and Applications of Jolywood N-Type TOPCon Technology).
With optimization approaches such as implementing selective emitters, optimization of anti-reflective coatings and electrodes and reducing the thickness of polycrystalline silicon film, Jolywood aims to hit 25% efficiency by second half of 2022. Adapting the TOPCon structure also on the emitter side, but selectively under the contact with local polycrystalline, the company is expected to gain about 0.2% absolute, which is expected to be accomplished in 2024. Employing high quality wafers is expected to bring the last leg of the improvement, reaching 25.52% by 2025, according to Jolywood. The company is also planning to progress to a next generation cell technology, such as the tandem structure, also based on TOPCon, which is used as the base and perovskite on top, to break the 26% barrier for a crystalline silicon cell (see Several Paths To TOPCon Cells).
This brief article is taken from our recent TaiyangNews report on TOPCon Solar Technology, which is available for free download here.
TaiyangNews Conference on High Efficiency Solar Technologies, on Day 3, focussed on TOPCon Cell. To learn more about the conference and view the presentations from varios market leaders click here