SK Nexilis copper-foil patent dispute highlights U.S.-UPC divide over claim construction

Context:

• SK Nexilis, the copper foil business of South Korea’s SKC Co., sued local rival Solus Advanced Materials and several Volta Energy Solutions units in the U.S. District Court for the Eastern District of Texas in November 2023. Solus makes copper foil for electric vehicle batteries, and its Volta units handle European sales and production.
• A jury found in May 2026 that Solus and the Volta units willfully infringed five SK Nexilis patents and awarded $3.3 million (jury verdict and judgment below box). Judge Rodney Gilstrap entered judgment on June 2, 2026, but declined to enhance damages despite the willfulness finding. The U.S. case is not over, though. Post-trial motions are pending, including SK Nexilis’s request for a permanent injunction and ongoing royalties, on which Judge Gilstrap held a hearing on September 9, 2026. Most of these filings are sealed, so the scope of the requested injunction is not public (details below).
• In September 2025, SK Nexilis also announced it had filed two suits at the UPC over European sales (September 29, 2025, SKC, press release). One of them concerns EP3316363 (“Electrolytic copper foil, current collector including same electrolytic copper foil, electrode including same current collector, secondary battery including same electrode, and method for manufacturing same”), the European counterpart of U.S. Patent No. 10,480,090 (“Electrolytic copper foil, current collector comprising the same, electrode comprising the same, secondary battery comprising the same, and method for manufacturing the same”), one of the five patents in the Texas verdict. The key term in that patent is “peak count roughness” (Rpc). It counts the peaks along a measured stretch of the foil’s surface profile, so a higher number means a more finely textured foil. Claim 1 of EP’363 requires an Rpc of 10 to 100. The dispute is over what length that count is measured across.