Duesenfeld GmbH has secured favorable rulings from patent authorities in both Europe and the United States, reinforcing its intellectual property rights for vacuum drying technology applied in lithium-ion battery recycling. In European opposition proceedings initiated by Volkswagen AG, the European Patent Office upheld European Patent EP 3 289 627 in an amended but fully enforceable form, ensuring ongoing protection of Duesenfeld’s core process in Europe.
In the United States, the company achieved success on multiple fronts. A post-grant review petition against US Patent No. 12,119,463 B2, filed by Ascend Elements, Inc. amid infringement litigation, was rejected on its merits by the United States Patent and Trademark Office in October 2025. This decision affirms the validity and enforceability of the patent covering Duesenfeld’s vacuum drying approach.
Separately, Ascend Elements and URT Umwelt- und Recyclingtechnik GmbH each challenged US Patent No. 11,050,097 through inter partes review proceedings. After consideration, the USPTO dismissed both challenges, confirming most claims as originally issued and upholding the remaining claims in amended form.
Duesenfeld’s patents protect a low-temperature vacuum drying process that prevents the formation of hazardous hydrogen fluoride, allows high-purity solvent recovery, and preserves lithium salts in their original chemical form (LiPF₆). This method reduces energy consumption, maintains a favorable CO₂ balance, and supports the sustainable recovery of key raw materials such as cobalt, nickel, and lithium. The process has advanced from concept to commercial scale, with three large-scale recycling plants currently under construction in Europe.
“These decisions not only confirm the technical substance of our patents, but also underscore the strength of our intellectual property portfolio,” commented Till Bußmann, CTO at Duesenfeld GmbH. “The rulings protect years of research and innovation and secure our leading position in the field of sustainable, safe, and efficient recycling of lithium-ion batteries.”
By affirming the validity of its vacuum drying patents, Duesenfeld reinforces competitive balance in the battery recycling industry and solidifies its role as a pioneer in circular economy solutions.
Source: Duesenfeld Press Release
