Image: DAS Solar
DAS Solar has taken a formal step toward industrializing back-contact (BC) solar cells, following the publication of an Environmental Impact Assessment (EIA) public-participation notice for a 5 GW BC high-efficiency cell project in Guizhou Province.
The filing, issued on Sept. 8 by Weining County authorities, lists Das Solar New Energy Technology (Weining) Co. as the project developer. The proposed 177,000-square-meter site will house cell workshops, chemical storage facilities, wastewater treatment, a 110 kV substation, and related infrastructure.
The project remains at the EIA disclosure stage, with no final construction schedule or capital budget released. However, DAS Solar signed a CNY 2 billion (US$280.7 million) agreement with Weining authorities in April 2024 for an n-type cell project. The company also completed a 2.4 GW n-type TOPCon module line in January 2024, representing a CNY 310 million investment and an estimated annual output value of CNY 2.5 billion. If the earlier CNY 2 billion framework is linked to the new 5 GW facility, it would imply a notional development cost of about CNY 400 million per GW—pending official confirmation.
Strategically, the move underscores DAS Solar’s shift from a TOPCon-only focus toward a dual-track cell technology roadmap. The company’s “DBC” architecture adapts the SiOx/Poly-Si passivated contact structure of TOPCon to the cell rear side, integrating it with a full back-contact design. This results in a metal-free front surface, improved current density, and preservation of TOPCon’s cost advantages.
DAS Solar recently reported third-party verification of its DBC performance, with the China Photovoltaic Testing Center (CPVT) certifying a cell efficiency of 27.77% and an open-circuit voltage of 745.7 mV. The company says it has filed more than 60 patents related to BC technology and has contributed to drafting around 20 industry and group standards.
The company’s latest platform, “DBC 3.0 Plus,” is said to be compatible with TOPCon-5.0 manufacturing processes and ready for mass production in 2025, targeting distributed generation and building-integrated PV (BIPV). At SNEC PV+ 18th (2025) in Shanghai, DAS Solar showcased its “Diamond” DBC module, rated at 670 W with 24.3% efficiency.
