CosMX and ATL take laptop battery fight to next round

Chinese battery manufacturers Zhuhai CosMX and ATL continue their battle in German courts over lithium-ion batteries. The Federal Patent Court has now upheld an ATL patent with some restrictions, which could impact the second-instance infringement hearing.

The dispute is part of a larger series of ongoing conflicts between the parties, including proceedings in the US and China. In March 2024, Munich Regional Court found CosMX and laptop manufacturer Acer had infringed ATL’s patent (case IDs: 44 O 11698/22 and 44 O 11725/22).  Now, the Federal Patent Court under presiding judge Walter Schramm has upheld EP 3 627 606 B1 with restrictions.

The patent owner is the China-based company Ningde Amperex Technology, known as ATL. The patent protects an electrolyte composition that prevents premature degradation of the electrolyte in a battery. This improves the performance of lithium-ion batteries used in devices such as laptops.

ATL’s Chinese competitor Zhuhai CosMX Battery filed the first nullity suit in May 2023 (case ID: 3 Ni 12/23). After the Federal Patent Court indicated in a preliminary opinion that the patent might be valid, and in light of ongoing infringement proceedings before the Munich Regional Court, CosMX changed its advisors and filed a second nullity action in July 2024.

Second nullity claim partly successful
CosMX filed the second action through its subsidiary Zhuhai CosMX Power (case ID: 3 Ni 12/24). The Federal Patent Court combined both proceedings for a joint hearing and decision.

In the oral hearing, the court addressed to what extent reworking an electrolyte composition disclosed in prior art can lead to the claimed subject matter. CosMX submitted tests from three institutes to scrutinise the effect of individual electrolyte components. The court followed this argumentation and limited the scope of the patent. This limitation could now impact the pending infringement proceedings.

The infringement judgments are under appeal. The Higher Regional Court Munich has scheduled an oral hearing for 19 March 2026. Additionally, after ATL partly enforced the first-instance decision against CosMX, Munich Regional Court found CosMX to be out of compliance with the judgment and issued a penalty order, which CosMX is also appealing.

Internationally, there are parallel proceedings in China and the US, which also concern other patents from the same patent family. Most recently, the Eastern District of Texas revoked one of the patents.