Duesenfeld Succeeds in Patent Defense against Volkswagen AG, Ascend Elements, Inc., and URT Umwelt- und Recycling Technik GmbH in Europe and the United States

Wendeburg, Germany – December 2025

Duesenfeld GmbH announces a series of significant legal victories in defending its core patents for vacuum drying technology used in the recycling of lithium-ion batteries. These victories before the European Patent Office (EPO) and the United States Patent and Trademark Office (USPTO) strengthen Duesenfeld's position as a global technology leader and protect its innovations from challenges by the industry.

European Patent Office confirms validity of patent at first instance

In opposition proceedings initiated by Volkswagen AG against European patent EP 3 289 627, which concerns Duesenfeld's vacuum drying process, the EPO confirmed the patent in an amended but fully enforceable form. The patent remains in force and ensures the continued protection of Duesenfeld's proprietary technology in Europe.

Success in the USA – Post-Grant Review Rejected

As part of ongoing infringement proceedings brought by Duesenfeld GmbH against Ascend Elements, Inc. for unauthorized use of Duesenfeld's patented technology, Ascend Elements requested a review of US Patent No. 12,119,463 B2. In October 2025, the USPTO rejected the request on the merits, confirming the validity of the patent and strengthening its enforceability.

Further successes in the USA – Inter Partes Reviews

Both Ascend Elements, Inc. and URT Umwelt- und Recyclingtechnik GmbH attempted to invalidate US Patent No. 11,050,097 through separate IPR proceedings. After initiating the proceedings and reviewing the case, the USPTO rejected both challenges, confirmed the validity of most claims as originally issued, and upholding other claims in amended form.

The Duesenfeld patents challenged in the US and Europe relate to vacuum drying processes and play a key role in the reuse of lithium-ion batteries and the recycling of raw materials such as cobalt, nickel, and lithium. Unlike conventional processes, Duesenfeld's process prevents the formation of hazardous hydrogen fluoride and enables high-purity solvent recovery, preserving the lithium salts in their original chemical form (LiPF₆). The low-temperature process reduces energy consumption and ensures a positive CO₂ balance. These advantages make Duesenfeld's process unique, which is confirmed by the fact that the company has successfully implemented this innovation from concept to commercial scale – with three large-scale plants currently under construction in Europe.

Significance for Duesenfeld

“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.”

These rulings have examined and validated Duesenfeld's patents. This outcome enables a rebalancing of competitive conditions in the battery recycling industry and secures the company's pioneering role in the research and development of circular economy solutions for battery recycling.

About Duesenfeld GmbH

Duesenfeld is a pioneer in the recycling of lithium-ion batteries and has developed processes that eliminate the need for conventional melting or heating of the batteries. From the very beginning, Duesenfeld's processes have been environmentally friendly, with a focus on CO2 avoidance and high recycling efficiency.

Duesenfeld licenses the technology worldwide.

Contact:

phone: +49 5303 508280
media@duesenfeld.com
www.duesenfeld.com