SK Nexilis develops copper foil for cylindrical batteries

South Korea's SK Nexilis, a maker of copper foil for secondary cells under SKC Inc., has achieved a world first with its development of a highly elongated 'V copper foil' for the next-generation high-capacity cylindrical 4680-type battery, which is 46 mm wide and 80 mm tall. Demand for the foil is expected to soar in tandem with that for cylindrical cells.

SK Nexilis on Sunday said its V copper foil has a success rate of not breaking when stretched, or the elongation ratio, 30% higher than other products on the market. The foil has also passed client evaluations worldwide in a first for the global copper foil industry, and installation is expected after the mass output of t4680 cells begins. The company said it expects to launch mass production next year.

The high-capacity cylindrical cell led by the 4680 type has five to six times more energy density and output than the existing 2710 type, as well as lower manufacturing costs and superior performance than pouch or prismatic cells. Major electric vehicle makers are thus strongly considering adopting the model.

The global market for cylindrical cells through 2030 is expected to grow at a high average clip of 23% per year focused on high-capacity products, and that for copper foil used in such batteries is projected to jump from 43,000 tons this year to 230,000 by 2030.

Demand for the V copper foil is also seen to surge. The 4680-type cell has higher capacity than conventional cylindrical models and needs an extremely high elongation rate, making it competitive in this aspect.

An SK Nexilis source said, "Through a high elongation rate, our V copper foil makes up for the problem of anode material expansion during charging and discharging. The foil is suitable for cylindrical secondary cells with relatively strong expansion due to the battery's structure."

Through the development of its V copper foil, the company has secured a product lineup with all the physical properties in demand by clients. And in an industry first, it secured mass production technology for ultra-high-strength 'U copper foil' with a tensile strength of 65 kg-force per square mm.

SKC plans to focus more on copper foil thanks to the growth of affiliate SK Nexillis. The strategy is to boost profitability by fostering copper foil and considering it a future growth engine instead of the sluggish chemical business. Also under consideration is setting up an incorporated subsidiary in North America.

Write to Seo-Woo Jang at suwu@hankyung.com