Tongwei Solar's has developed p-TBC, n-TBC, and n-HTBC cell structures at its R&D center, which reach up to 25.21%, 26.66%, and 27% efficiency, respectively
It has a TNC technology roadmap of advancing up to TNC 2.0 version with 26.5% efficiency from the existing TNC 1.0 level of 25.4%
The company's latest multi-scenario TNC modules are all made up of G12 or G12R size TNC cells
Leading Chinese PV manufacturers have outpaced Europe, once at the pinnacle of PV technology, over the last decade. This has been primarily catalyzed by consistent investment in R&D, among other factors. Several Chinese PV manufacturers have leveraged their fully vertically integrated manufacturing capabilities to successfully commercialize new PV technologies, scaling them from lab-scale to mass production.
At the recent TaiyangNews High-Efficiency Solar Technologies Conference 2024, Jerry Jiang, Regional Technical Service Director at Tongwei Solar, provided a brief overview of the company's advancements and the roadmap for cell technology, as well as its latest module offerings (see Tongwei Solar presentation here).
Tongwei Solar, based in Chengdu, China, is a fully vertically integrated PV manufacturing company, with operations spanning from polysilicon to modules. It operates based on a dual-green strategy – Green Agriculture and Green Energy. Its annual vertically integrated manufacturing capacities are distributed as follows: up to 850,000 tons of polysilicon, 20 GW of ingots and wafers, 126 GW of PV cells, and 85 GW of PV modules. The 4 polysilicon production bases are located in Tongwei Yunnan, Yongxiang New Energy, Yongxiang Polysilicon, and Tongwei Inner Mongolia. For cell and module production, the company has 6 production bases within China.
R&D Progress Status
Tongwei Solar, with an R&D investment of $568.9 million – equivalent to 2.86% of its 2023 revenue – has established a global innovation and R&D center in Chengdu, China. The center spans an area of 270,000 m², with 108,000 m² dedicated to R&D workshops. This integrated facility houses a TNC cell pilot line, TBC cell and module pilot lines, a module R&D center, and an HJT + GW-level perovskite cell lab. The company’s R&D portfolio covers a wide range of technologies, including PERC, TOPCon, HJT, XBC, and perovskite/tandem cell technologies.
After providing an overview of the company’s R&D activities, Jiang presented the latest innovations in n-type cell technology platforms. These platforms combine p-PERC cells and TNC cell structures into a back-contact configuration, resulting in the p-TBC cell. The p-TBC cell features a 730 mV Voc, up to 25% efficiency, and bifaciality of up to 60%. By shifting both the front and back contacts to the rear side of the TNC cell structure, the company developed an n-TBC cell, which delivers a Voc of up to 743 mV, an efficiency of up to 26.5%, and bifaciality of up to 70%. A comparative analysis of p-TBC and n-TBC technologies revealed that cheaper p-type wafers are more prone to degradation compared to traditional n-type BC technology. Additionally, p-TBC cells exhibit lower minority carrier lifetime, which leads to reduced efficiency and a lower bifacial factor. Meanwhile, the company’s n-HTBC cell structure – a combination of n-TOPCon and n-HJT cell technologies – has achieved up to 27% efficiency and up to 75% bifaciality.
Starting with the TBC pilot line in Q2 2022, the company’s latest BC technology report shows that as of December 2023, p-IBC or p-TBC technology achieved up to 25.51% efficiency, while n-IBC cell technology reached up to 26.66% efficiency by August 2024. Following the progress in BC technology, the company introduced the TNC cell technology roadmap. This includes upgrading the TBC 1.0 version, which achieves up to 25.4% mass production efficiency, to the TBC 2.0 version, with the potential to reach up to 26.5% efficiency at mass scale by incorporating multiple technological advancements. Key pathways for further progress include the integration of EPT, 0BB technology, advanced printing technology with improved metallization paste, and high-quality wafers.
In terms of its module offerings, the company has transitioned to TNC G12 and TNC G12R-size cells, moving from the TNC M10 size. The TNC-G12R 48 series module, featuring 48 G12R TNC cells, delivers up to 455 W of power, representing a 15 W relative power gain compared to the TNC-M10 54 series module. This module, with an active area of less than 2 m² and a weight of 20.9 kg, is suitable for residential applications and is available in various types, including all-black or transparent versions. The TNC-G12R 54 series module, equipped with 54 G12R TNC cells, suitable for commercial and industrial (C&I) applications, boasts a power output of up to 515 W and an efficiency of up to 23.2%. For utility applications, Tongwei offers TNC-G12R 66 and TNC-G12R 66 series modules with a maximum power output of up to 635 W and 725 W, respectively. Both module series offer product warranties of up to 12 years and a 30-year performance warranty.