Trina Solar v. Canadian Solar defendants

Trina Solar (U.S.), Inc., Trina Solar US Manufacturing Module 1, LLC, and Trina Solar Co., Ltd. (collectively, "Trina") initiated this patent infringement litigation against Canadian Solar Inc., CSI Solar Co., Ltd., Canadian Solar (USA) Inc., Canadian Solar Manufacturing (Thailand) Co., Ltd., Canadian Solar US Module Manufacturing Corporation, and Recurrent Energy Development Holdings, LLC (collectively, "Canadian Solar defendants"). Both Trina Solar and Canadian Solar are prominent global players in the solar energy industry, involved in the research, development, manufacturing, and sales of photovoltaic (PV) products, including solar cells, modules, and complete energy solutions. Trina Solar operates a vertically integrated production process, covering solar wafers, cells, and modules. Similarly, Canadian Solar is a leading manufacturer of solar PV modules and provides battery energy storage solutions, as well as developing utility-scale solar power and battery energy storage projects.

The core of the dispute revolved around alleged infringement of Trina Solar's Tunnel Oxide Passivated Contact (TOPCon) solar cell technology. The accused products were "certain TOPCon solar cells, modules, panels, components thereof, and products containing the same" imported into or sold within the United States. TOPCon is a critical innovation designed to enhance solar cell efficiency by employing an ultra-thin tunnel oxide layer coupled with a highly doped polysilicon layer to minimize energy losses. The asserted patents in this investigation were U.S. Patent No. 10,230,009 ("the '009 patent") and U.S. Patent No. 9,722,104 ("the '104 patent"), both generally titled "Solar Cell and Method for Manufacturing the Same" and pertaining to structural and process innovations aimed at improving solar cell efficiency and manufacturing scalability.

This litigation commenced on October 23, 2024, when Trina Solar filed a complaint with the U.S. International Trade Commission (ITC), leading to the institution of investigation 337-TA-1425 on December 9, 2024. This ITC investigation was subsequently consolidated with a related Trina Solar complaint (337-TA-1422) against other entities like Runergy and Adani on January 21, 2025. The ITC is a significant forum for patent disputes involving imported goods, offering powerful remedies such as Limited Exclusion Orders, which can bar infringing products from entering the U.S. market, and Cease and Desist Orders to prevent further sales. However, despite initial expectations for preliminary and final rulings in 2026, the ITC investigation 337-TA-1425 (and its consolidated counterpart) was terminated in its entirety on February 10, 2026, following an initial determination granting a joint motion to terminate the investigation. The specific reasons for this termination were not publicly disclosed in detail, but such outcomes often suggest a settlement, licensing agreements, or strategic consolidation of proceedings. Adding to the notability of the case, on April 17, 2026, the U.S. Patent Trial and Appeal Board (PTAB) issued final written decisions invalidating all claims of both asserted patents, 9,722,104 and 10,230,009. This PTAB ruling effectively removed the legal foundation for Trina Solar's parallel patent infringement lawsuit against Canadian Solar in the U.S. District Court for the District of Delaware, which had been stayed pending the ITC investigation and inter partes reviews. This outcome represents a significant victory for Canadian Solar in this particular U.S. patent dispute, though the broader IP competition between the solar giants continues, including a separate lawsuit filed by Trina Solar against Canadian Solar in China.

Trina Solar's patent infringement litigation against Canadian Solar defendants at the U.S. International Trade Commission (ITC), Investigation No. 337-TA-1425, saw a swift resolution through termination based on a joint motion by the parties in early 2026.

Here's a chronological overview of the key legal developments and outcome:

• Filing & Initial Pleadings:

  • On October 23, 2024, Trina Solar (U.S.), Inc., Trina Solar US Manufacturing Module 1, LLC, and Trina Solar Co., Ltd. (collectively, "Trina") filed a complaint with the ITC, alleging violations of Section 337 of the Tariff Act of 1930. The complaint accused Canadian Solar Inc. and several of its affiliated entities (collectively, "Canadian Solar") of infringing U.S. Patent Nos. 9,722,104 and 10,230,009, relating to TOPCon solar cell technology. Trina sought a limited exclusion order and cease-and-desist orders.
  • The ITC officially instituted Investigation No. 337-TA-1425 on December 9, 2024.

• Pre-trial Motions of Substance:

  • On January 21, 2025, the Commission consolidated Investigation No. 337-TA-1425 with a related investigation, 337-TA-1422, citing similar complainants, domestic industry allegations, patents, and products. The initial target date for completion of the consolidated investigation was set for April 20, 2026, which was later amended to May 20, 2026.
  • The investigation saw some respondents terminated early. An Initial Determination (Order No. 8) on January 14, 2025, granted Trina's unopposed motion to terminate the investigation as to respondent Adani Green Energy Ltd. and to add Mundra Solar PV Ltd. as a respondent. This determination was not reviewed by the Commission and became final on January 31, 2025 (published February 3, 2025).
  • Additionally, on February 12, 2025 (published February 13, 2025), the Commission determined not to review Order No. 7, which granted Trina's unopposed motion to withdraw the complaint and terminate the investigation as to respondent Recurrent Energy Development Holdings LLC.

• Claim Construction (Markman) & Discovery:

  • While specific dates for a Markman hearing or detailed claim construction outcomes were not widely publicized in the available records, the ITC docket indicates that an evidentiary hearing commenced on January 12, 2026, and concluded on January 16, 2026. In ITC investigations, claim construction typically occurs early in the process to guide discovery and trial.

• Trial Events, Verdict & Post-Trial Motions:

  • An Initial Determination (ID) was issued by the Administrative Law Judge (ALJ) on January 14, 2026. This ID was categorized as "Non-Final, Terminating."

• Settlement, Dismissal, Judgment, or Appeal:

  • The investigation was terminated in its entirety on February 10, 2026. This termination resulted from the Commission's decision not to review an Initial Determination (Order No. 40) that granted a joint motion by the parties to terminate the investigation. This suggests a settlement or mutual agreement between Trina Solar and the Canadian Solar defendants led to the complete termination of the investigation.

• Parallel PTAB IPR/PGR Proceedings:

  • No publicly available information indicates any parallel PTAB IPR (Inter Partes Review) or PGR (Post-Grant Review) proceedings initiated against US Patent 10,230,009 in connection with this ITC investigation. The termination of the ITC investigation makes it less likely for such proceedings to be pursued aggressively unless the underlying dispute continues in other forums.

The following attorneys from Levi Snotherly & Schaumberg, PLLC represented Trina Solar (U.S.), Inc. and Trina Solar Co., Ltd. in ITC Investigation No. 337-TA-1425:

• Ben Levi

  • Role: Principal Counsel
  • Firm: Levi Snotherly & Schaumberg, PLLC, Washington, D.C.
  • Note: Mr. Levi is a trial lawyer and registered patent attorney with nearly 30 years of experience litigating complex patent disputes in the U.S. International Trade Commission (ITC) and federal District Courts. He has particular expertise in guiding clients through ITC litigation and previously served as a senior investigative attorney with the ITC's Office of Unfair Import Investigations.

• Rett Snotherly

  • Role: Principal Counsel
  • Firm: Levi Snotherly & Schaumberg, PLLC, Washington, D.C.
  • Note: Mr. Snotherly has spent his entire legal career on high-stakes litigation, with a primary focus on ITC matters. He has significant expertise in handling patent infringements, including representing clients in ITC Inv. No. 337-TA-1425. Prior to co-founding the firm, he guided legal strategy in ITC investigations as Senior Counsel & Director for a large Asian conglomerate and was a Senior Investigative Attorney at the ITC's Office of Unfair Import Investigations, where he was lead counsel in numerous investigations.

• S. Tom M. Schaumberg

  • Role: Principal Counsel
  • Firm: Levi Snotherly & Schaumberg, PLLC, Washington, D.C.
  • Note: Mr. Schaumberg is esteemed for his decades of ITC expertise, having litigated Section 337 unfair competition cases for over 40 years before the ITC and the Court of Appeals for the Federal Circuit.

Trina Solar (U.S.), Inc. and Trina Solar Co., Ltd. were named as complainants in the investigation. The ITC investigation 337-TA-1425 was consolidated with 337-TA-1422 on January 21, 2025, and subsequently terminated in its entirety on February 10, 2026, based on a joint motion by the parties. The specific basis of termination was not publicly disclosed in available case records.

US International Trade Commission Investigation No. 337-TA-1425, "Certain TOPCon Solar Cells, Modules, Panels, Components Thereof, and Products Containing Same II," has been terminated.

On February 10, 2026, the U.S. International Trade Commission (ITC) determined not to review an initial determination granting the parties' joint motion to terminate the investigation in its entirety. This consolidated investigation, which included 337-TA-1425 and 337-TA-1422, was instituted based on complaints filed by Trina Solar against Canadian Solar and other entities. As such, there is no currently active counsel of record for the defendant(s) in this case as the investigation has concluded.

However, during the active phase of the investigation, Canadian Solar (USA) Inc. and CSI Solar Co., Ltd., named as respondents, were represented by external counsel from Sidley Austin LLP. While specific individual attorneys are typically listed on the official ITC docket, public search results identify Sidley Austin LLP as the participant representative for Canadian Solar entities.

Counsel of Record (during the active phase of the investigation):

• Firm: Sidley Austin LLP
  • Role: External Counsel
  • Office Location: While the specific office location for the attorneys handling this particular ITC matter is not detailed in the provided search snippets, Sidley Austin has a strong presence in Washington D.C., a common location for ITC litigation.
  • Note: Sidley Austin has an established intellectual property litigation practice, frequently representing clients in Section 337 investigations before the ITC.

In-House Counsel for Canadian Solar:

While external counsel typically leads ITC investigations, in-house legal teams play a crucial supporting role. John Marner is noted as the Senior Director and General Counsel for Canadian Solar, overseeing legal aspects of the company's global operations, including intellectual property and litigation management. Other "Sr. Legal Counsel" or "Legal Counsel" roles at Canadian Solar are involved in managing litigation and providing legal support across various business units.

• Name: John Marner
  • Role: Senior Director and General Counsel
  • Firm: Canadian Solar (in-house)
  • Office Location: Canadian Solar is based in Guelph, Ontario, with legal teams supporting global operations, including the U.S.
  • Note: Oversees the development, construction, and sale of solar farms globally, and has experience with managing external counsel in litigation.