DAS Solar has taken a formal step toward industrializing BC solar cells after local authorities in Guizhou published an EIA public-participation notice for a 5 GW BC high-efficiency cell project.
The Weining County filing, dated Sept. 8, identifies the developer as Das Solar New Energy Technology (Weining) Co. and lists a 177,000-square-meter site planned for cell workshops, chemical stores, wastewater treatment, a 110 kV substation and associated support infrastructure.
The project remains at the EIA disclosure stage. The company and local government have not published a detailed construction timetable or final capital budget.
Das Solar signed a CNY 2 billion (280.7 million) agreement with the Weining authorities in April 2024 for a related n-type cell project. The company’s existing Weining manufacturing base also completed a 2.4 GW n-type tunnel oxide passivated contact (TOPCon) module line in January 2024 with a reported investment of CNY 310 million and an annual output value of about CNY 2.5 billion. If the earlier CNY 2 billion framework corresponds to the new 5 GW factory, that would imply a development cost of roughly CNY 400 million per GW – a notional figure that requires official confirmation.
Technically, the move reflects a deliberate shift from DAS Solar’s established TOPCon expertise toward a dual-track strategy. The company describes its BC approach as “DBC” – a hybrid that transfers TOPCon’s SiOx/Poly-Si passivated contact architecture to the rear of the cell and combines it with a full back-contact design. The intended result is a front surface free of metal busbars, higher current density and retention of TOPCon’s cost characteristics.
DAS Solar claimed third-party verification for recent performance gains: a DBC cell registered at 27.77% efficiency with an open-circuit voltage of 745.7 mV, certified by the China Photovoltaic Testing Center (CPVT). It said it has filed more than 60 patents related to BC technology and has led drafting of some 20 industry and group standards.
DAS Solar added that its “DBC 3.0 Plus” is compatible with TOPCon-5.0 process flows and ready for scale-up in 2025, with an initial market focus on distributed generation and BIPV. At the module level, the company showcased a “Diamond” DBC product at SNEC PV+ 18th (2025) International Photovoltaic Power Generation and Smart Energy Conference and Exhibition, advertising a 670 W output and 24.3% module efficiency.
DAS Solar remains an active TOPCon player. Since its founding in 2018, it has advanced TOPCon through successive generations, reporting a 2024 mass-production average module efficiency of 26.7% and continued process upgrades into 2025. The company said it has built about 40 GW of battery and module capacity across several Chinese provinces and aims to lift component capacity toward 50 GW by the end of 2025.
According to market research firm PV InfoLink, DAS Solar was the world’s ninth-largest module supplier in 2024.
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