Wedoany.com Report-Sept. 16, DAS Solar has moved forward with industrializing back-contact (BC) solar cells after local authorities in Guizhou issued an environmental impact assessment (EIA) public-participation notice for a 5 GW BC high-efficiency cell project. The filing, dated September 8, identifies the developer as Das Solar New Energy Technology (Weining) Co. and outlines plans for a 177,000-square-meter site in Weining County. The site will include cell workshops, chemical storage facilities, wastewater treatment systems, a 110 kV substation, and other supporting infrastructure.
The project is still at the EIA disclosure stage, and neither the company nor the local government has released a detailed construction timeline or final investment figures. In April 2024, DAS Solar signed a CNY 2 billion (USD 280.7 million) agreement with Weining authorities for a related n-type cell project. Earlier, in January 2024, its Weining base completed a 2.4 GW n-type tunnel oxide passivated contact (TOPCon) module production line with an investment of CNY 310 million and an annual output value of about CNY 2.5 billion. If the April 2024 agreement applies to the new 5 GW facility, the notional development cost would be around CNY 400 million per GW, though this awaits official confirmation.
Technically, the new project reflects DAS Solar’s shift toward a dual-track strategy, balancing its existing TOPCon expertise with BC cell development. The company describes its approach as “DBC,” a hybrid design that applies TOPCon’s SiOx/Poly-Si passivated contact structure to the rear of the cell while adopting a full back-contact configuration. This eliminates metal busbars from the front surface, enhances current density, and maintains the cost advantages of TOPCon.
DAS Solar reported progress with verified performance results. A DBC cell achieved 27.77% efficiency and an open-circuit voltage of 745.7 mV, as certified by the China Photovoltaic Testing Center (CPVT). The company also stated it has filed more than 60 patents connected to BC technology and has contributed to drafting about 20 industry and group standards. It added that its “DBC 3.0 Plus” is compatible with TOPCon-5.0 process flows and ready for large-scale production in 2025, targeting distributed generation and building-integrated photovoltaics (BIPV). At the module level, DAS Solar introduced its “Diamond” DBC product at the SNEC PV+ 18th (2025) International Photovoltaic Power Generation and Smart Energy Conference and Exhibition, featuring a 670 W output and 24.3% module efficiency.
Alongside its BC advancements, DAS Solar continues to strengthen its TOPCon portfolio. Since its founding in 2018, the company has pursued multiple generations of TOPCon upgrades, reporting an average module efficiency of 26.7% in mass production during 2024 and ongoing process improvements into 2025. It has built about 40 GW of battery and module capacity across several provinces in China and plans to expand to 50 GW by the end of 2025.
According to PV InfoLink, DAS Solar ranked as the world’s ninth-largest module supplier in 2024, reflecting its growing role in global photovoltaic development.
