South Korean chemical firm LG Chem Ltd has filed a patent infringement lawsuit against Jaesae Neungwon, the local subsidiary of Chinese battery producer Ningbo Ronbay New Energy Technology Company, according to local reports citing industry sources.

The lawsuit is understood to have been filed in August at the Seoul Central District Court over allegations of patent infringement related to cathode materials—a key component accounting for roughly 40% of the cost of lithium-ion batteries used in electric vehicles. Lithium-ion batteries are used in a wide range of electronic products, energy storage systems (ESS) as well as in EVs.

LG Chem claims that Ronbay’s local subsidiary has used its NCM (Nickel, Cobalt, Manganese) cathode material technology patents without authorisation. Reports suggest the alleged patent infringement claim centres on five patents relating to the structure and characteristics of the particles of the cathode active material.

LG Chem stated that it analyzed samples of Ronbay's cathode materials produced at its plant in Chungju, in South Korea’s North Chungcheong province, and confirmed multiple patent infringements.

Shanghai-listed Ronbay has challenged the validity of the patents, arguing: "The patents acquired by LG Chem are invalid and we are filing for an invalidation trial and a confirmation of the scope of rights.” Ronbay suggested that LG Chem acquired two of the main patents in question from Hanyang University in 2022, which have issues with “patent specification and lack novelty.”

Jaesae Neungwon is building a second cathode materials plant in Chungju and plans to start constructing a third plant in the country next year, with the aim of having a total production capacity of 100,000 tons of cathode materials per year as it seeks to shake up South Korea’s battery supply chain.