The U.S. Patent Trial and Appeal Board has issued Final Written Decisions invalidating all claims of two TOPCon solar cell patents previously held by Trina Solar Co., Ltd., Canadian Solar Inc. (NASDAQ: CSIQ) announced.

The patents, which cover Tunnel Oxide Passivated Contact solar cell technology, had been asserted by Trina Solar against certain subsidiaries of Canadian Solar in previous litigation.

The Patent Trial and Appeal Board operates under the U.S. Patent and Trademark Office and handles patent validity disputes. TOPCon technology is used in solar cell manufacturing to improve energy conversion efficiency.

"Canadian Solar has always remained committed to organic and independent R&D," said Colin Parkin, President of Canadian Solar and President of e-STORAGE. "While we respect and value the intellectual property rights of all companies as we do our own, we firmly oppose the abusive use of IP to extort or hinder competition."

Canadian Solar, founded in 2001 and headquartered in Kitchener, Ontario, manufactures solar photovoltaic modules and develops utility-scale solar power projects. The company has delivered over 174 GW of solar photovoltaic modules globally over 25 years, according to the press release statement.

Through its e-STORAGE subsidiary, Canadian Solar has shipped over 18 GWh of battery energy storage solutions as of December 31, 2025, with a $3.6 billion contracted backlog as of March 13, 2026.