First Solar has filed a Sec. 337 investigation request with the U.S. International Trade Commission (ITC) on a swath of crystalline silicon panel competitors for allegedly infringing on First Solar’s TOPCon patents. A Sec. 337 of the Tariff Act violation declares that the infringement of certain patents leads to unfair competition in import trade.
Canadian Solar TOPCon module
First Solar filed the investigation request last week against Axitec, Canadian Solar, JA Solar, Jinko Solar, Mundra (Adani), Philadelphia Solar, Qcells, Runergy, Trina Solar (including T1 Energy) and VSUN (Toyo). First Solar, a cadmium-telluride (CdTe) thin-film solar panel manufacturer, holds one silicon solar panel patent involving tunnel oxide passivated contact (TOPCon) technology — U.S. Patent No. 9,130,074.
Toward the end of 2025, the U.S. Patent and Trademark Office validated First Solar’s TOPCon patent after Jinko, Mundra and Canadian Solar attempted to claim the designs were unpatentable.
First Solar has gone through with the Sec. 337 investigation request based on its licensing of the TOPCon patent to solar cell startup Talon PV. Talon is establishing a cell manufacturing operation outside of Houston and expects to begin supplying U.S. solar panel assemblers with M10 and G12 TOPCon cells sometime next year. Thus with a domestic industry established, First Solar can ask the U.S. government to review TOPCon imports for patent infringement.
First Solar has asked the ITC for a general exclusion order for any TOPCon solar cells entering the United States that have been manufactured using First Solar’s patent — which would include any solar panel made with the cells.
There’s been a lot of back-and-forth in the industry regarding TOPCon solar patents, with most manufacturers involved in lawsuits in some way. It is already altering the domestic manufacturing landscape, with the country’s only cell manufacturers sticking with PERC designs to avoid the IP mess. Who has the right to produce advanced n-type solar panel designs in the United States means more than just determining ownership of a novel technology. Drawn-out legal fights could set the United States even further behind China in solar panel manufacturing ability.
Trina Solar filed its own Sec. 337 request involving TOPCon patents against Runergy, Mundra/Adani and Canadian Solar in 2024. In February 2026, the investigation was terminated entirely, by request of Trina.
Another Sec. 337 investigation ongoing in the solar industry is Shoals’ filing against Voltage. The ITC issued an initial determination that Voltage cable management products did infringe upon Shoals patents. A final decision on the matter is scheduled for June 2026.
