US solar panel manufacturer First Solar has filed a patent lawsuit in the US District Court for the District of Delaware against Chinese competitor JinkoSolar. The lawsuit is related to US Patent No. 9,130,074, which First Solar said covers an unspecified TOPCon manufacturing technology.

“First Solar obtained the US TOPCon patents and related international counterparts through its 2013 acquisition of TetraSun, Inc.,” First Solar said in a statement. “The patents include issued patents in the United States, Australia, Canada, China, the European Union, Hong Kong, Japan, Mexico, Malaysia, Singapore, South Korea, the United Arab Emirates, and Vietnam with validities extending to 2030 and beyond. The portfolio also includes pending patent applications in the European Union, Japan, Hong Kong, United Arab Emirates, and Vietnam.”

In November 2024, First Solar sent letters through its attorneys to a number of major solar manufacturers, warning that it believed that its patents are being violated. The letters went to solar panel producers Longi, Trina Solar, Jinko Solar, JA Solar, and Canadian Solar.

Several leading manufacturers are actively asserting patent-related claims against each other, particularly in relation to TOPCon solar cell technology.

First Solar’s warning letter to its competitors claimed that the companies it listed have been using First Solar TOPCon patents without a license.