US Board Invalidates Trina Solar Patents in Case Involving Canadian Solar
In a significant development for the solar technology sector, the U.S. Patent Trial and Appeal Board (PTAB) has issued final written decisions invalidating all claims of two key patents held by Trina Solar. The ruling, announced on April 17, 2026, centers on TOPCon (Tunnel Oxide Passivated Contact) solar cell technology and stems from a legal dispute initiated by Trina against its major competitor, Canadian Solar.
Examining the Trina Solar Patent Invalidation
The PTAB, which is part of the U.S. Patent and Trademark Office, sided with Canadian Solar by invalidating the entirety of the two TOPCon patents. These patents were the foundation of a patent infringement lawsuit Trina Solar had previously filed against certain subsidiaries of Canadian Solar.
This decision effectively removes the asserted patent risk against Canadian Solar’s operations in the United States concerning these specific technologies. For Canadian Solar, the ruling is a major victory, reinforcing what the company describes as a strong track record in navigating and managing complex international intellectual property disputes.
Background of the Patent Dispute
The conflict began in October 2024, when Trina Solar filed a complaint for patent infringement in the U.S. District Court for the District of Delaware against three of Canadian Solar’s subsidiaries. This action set the stage for the subsequent review by the PTAB.
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The rivalry between the two solar giants is not confined to the United States. The legal battles extend globally, highlighting the intense competition in the high-efficiency solar cell market. In February 2025, Trina Solar also initiated legal proceedings in China against Canadian Solar and its subsidiary, Changshu Canadian Solar Energy Technology Co., Ltd. In that case, Trina is seeking approximately $147 million in damages, alleging infringement of two of its TOPCon solar cell technology patents in the Chinese market.
Implications for the Solar Industry
The invalidation of these patents in the U.S. is a crucial event in the ongoing “patent wars” within the solar industry. TOPCon technology is a critical area of innovation, offering higher efficiency rates than previous generations of solar cells. As companies invest heavily in research and development, protecting their intellectual property becomes paramount.
This ruling underscores the rigorous scrutiny patents can face and highlights the strategic importance of the PTAB as a venue for challenging patent validity. For now, Canadian Solar has cleared a significant legal hurdle in the U.S., allowing it to continue its activities related to TOPCon technology without the threat of infringement claims from these two specific Trina patents. The broader, international dispute, however, continues to unfold.
