JinkoSolar files second patent lawsuit against Longi in EU court

JinkoSolar claims Longi’s high-end back-contact (BC) solar products infringe on a former LG patent, which is now held by Jinko.

JinkoSolar’s subsidiary, Shangrao Jinko Xinyuan Yuedong, has filed a lawsuit in the Munich division of the Unified Patent Court, accusing Longi Green Energy and several of its European subsidiaries of infringing on European patent EP3297043.

The patent, originally owned by South Korea’s LG, relates to a solar cell structure based on “selective doping of the passivation layer” – a technology Jinko acquired in recent years through its strategic purchase of LG’s solar patent assets.

The case targets Longi’s premium BC solar module lines – Hi-MO 7, Hi-MO 9, and X10 – signaling Jinko’s shift in focus from earlier disputes over tunnel oxide passivated contact (TOPCon) technology to the increasingly competitive BC segment.

This is Jinko’s second suit against Longi in Germany this year. On Feb. 14, Jinko filed its first Unified Patent Court action concerning patent EP4372829B1, which is related to TOPCon.

While Longi has not publicly responded to the latest BC-related allegations, it has begun to push back. On July 21, the company filed for the invalidation of the February TOPCon patent at the Unified Patent Court. Media reports also suggest Longi has initiated countersuits in China, leveraging patents it purchased from Mitsubishi Electric.

In January, JinkoSolar also filed a patent infringement lawsuit against Longi over the use of an unspecified TOPCon solar cell technology at the Nanchang Intermediate People’s Court in China.

In early December 2024, JinkoSolar filed a patent infringement lawsuit against competitor VSUN, a unit of Japan’s Fujisolar, in the US District Court for the Northern District of California. JinkoSolar said it is suing VSUN and its US affiliates, but did not disclose the patent involved in the dispute.