Hogan Lovells Secures Key Win for ATL in International Battery Patent Case

On Tuesday 15 July 2025, the Court largely upheld European Patent EP 3 627 606 B1, which protects an innovative electrolyte composition designed to prevent premature degradation in lithium-ion batteries.

ATL’s patent aims to improve the performance and longevity of batteries which are used for example in end-user devices such as laptops. The patent was challenged by two nullity actions filed by ATL’s Chinese competitor Zhuhai CosMX Battery Co. Ltd. and its subsidiary Zhuhai CosMX POWER Co., Ltd at the German Patent Court. Following two preliminary opinions already favoring ATL, the Court consolidated the proceedings for a joint oral hearing that took place on 15 July 2025.

At the end of the hearing, the Court announced its judgment and upheld the patent in an only slightly narrowed form according to ATL’s first auxiliary request. The Court further ruled that CosMX has to bear 75 % of the costs of the proceedings.. An appeal of this judgment to the Federal Court of Justice is admissible.

This dispute is part of a broader and commercially significant international patent conflict between ATL and CosMX, with ongoing litigation in the US and China. In March 2024, the Munich Regional Court found Zhuhai CosMX Battery Co., Ltd and several companies affiliated with it to have infringed ATL’s patent by supplying batteries that use the patent. This infringement judgment is currently under appeal before the Higher Regional Court Munich, with a hearing scheduled for March 2026. Additionally, after partial enforcement of the first-instance rulings, the Munich District Court imposed a penalty on CosMX for non-compliance, which is also subject to appeal.

For ATL

Hogan Lovells: Dr. Steffen Steininger (lead infringement and overall coordination, partner); Dr. Daniel Kaneko (senior associate) (both Munich);

Weickmann & Weickmann: Dr. Stephan Jellbauer (lead nullity, patent attorney, partner), Dr. Bettina Bach (patent attorney, senior associate) (all Munich);

Abitz: Dr. Monica Heinemann (patent attorney, partner, Munich);

For CosMX 

Eisenführ Speiser: Dr. Michael Schneider, Dr. Philipp Rastemborski, Lukas Wosnitza (all lawyers);

Peter Wiegeleben, Uwe Stilkenböhmer, Martin Nohlen (all patent attorneys) (Munich/Bremen);

Federal Patent Court, Third Senate

Walter Schramm (presiding judge).