Evonik Launches New Processing Aids For Improving Photovoltaic Wafer Cutting

German speciality chemicals firm Evonik has launched its new processing aids portfolio under the brand name TEGO® Surten E in China. The firm claims that new additives improve the performance and efficiency of photovoltaic (PV) wafer cutting, leading to better overall performance and production efficiency of solar modules.

With many countries, including China, pledging their commitment to achieving carbon neutrality, better and more cost-effective utilization of renewable energy is vital. The Chinese solar industry, which has emerged as the world leading sector accounting for a majority of solar manufacturing, has been a key reason for the global drop in solar prices as well as improving efficiency.

However, the economic competitiveness of current PV systems compared to other energy options remains to be a key metric for the future development of the industry. Solar module manufacturers are looking for any opportunity to reduce production costs while improving the conversion efficiency of solar cells to electricity.

Cutting silicon ingots with diamond wire saws (DWS) is a crucial step in the production of PV cells based on crystalline silicon. Cutting fluids with standard surfactants do not meet the requirements of the latest high-performance cutting process: Deep cut lines and divots caused by ineffective swarf transport and degradation of the wire’s diamond coating not only lower wafer quality but can also lead to the formation of large crystals during the subsequent diffusion step, reducing the surface area for photon capture resulting in lower cell efficiency.

“The newly launched product series TEGO® Surten E for the PV industry expands our comprehensive additives portfolio for renewable energy manufacturing,” said Benjamin Brehmer, Global Segment Manager Energy & Storage at Evonik’s Interface & Performance business line, “These low-dose additives can significantly improve the quality and speed of PV wafer cutting, contributing to a further step forward on the road to a climate-neutral future.”

TEGO® Surten E wetting agents and defoamers aim to deliver the right balance of extremely low dynamic surface tensions and adhesion tendency to effectively remove cutting swarf. Evonik claims that cutting fluid formulations containing a low dosage of TEGO® Surten E can achieve a much better cut quality ratio (more A⁺ vs. A^–) at higher cutting speeds using smaller wire diameters, on ever larger wafers (M12). This leads to an improved economic balance with less costly post-treatment remedial work required for cut wafers. The optimized formulation ensures a consistent cut quality on larger wafers leading to a significant increase in overall PV energy output.

In addition, the ideal wetting behavior of TEGO® Surten E products can be modified to specifically operate under extreme operation conditions, such as in circular systems, by refining the overall cooling performance of the fluid. This helps to maintain the durability and performance of the diamond wire, improving the efficiency and sustainability of the whole process.

Evonik’s TEGO® Surten E surfactant portfolio can also be useful as a process additive in many related and emerging PV applications, such as supporting more uniform and improved anti-reflective and reflective coatings, as well as other engineered surface modifications that improve overall energy yield.

With solar manufacturing being pushed across more and more countries, especially India, Evonik surely will see the opportunity in India soon. The firm has been pushing its technology for CBG (Compressed Bio Gas) plants currently.