First Solar, Inc. v. Canadian Solar Inc.

First Solar, Inc. filed a patent infringement lawsuit against Canadian Solar Inc. in the United States District Court for the District of Delaware on May 9, 2025.

Plaintiff First Solar, Inc. is an American publicly traded manufacturer of solar panels, specializing in rigid thin-film modules that use cadmium telluride (CdTe) as a semiconductor. Headquartered in Tempe, Arizona, First Solar focuses on utility-scale photovoltaic (PV) systems and operates manufacturing facilities in the US, India, Malaysia, and Vietnam. Defendant Canadian Solar Inc. is a leading global solar technology and renewable energy company headquartered in Kitchener, Ontario, Canada. It manufactures solar photovoltaic modules, provides solar energy and battery energy storage solutions, and develops, owns, and operates utility-scale solar power and battery energy storage projects. Canadian Solar has manufacturing facilities in Asia and the Americas, including a solar module factory in Mesquite, Texas.

The lawsuit alleges that Canadian Solar Inc. infringes U.S. Patent No. 9,130,074 (the "'074 Patent"), which First Solar acquired in 2013 through its acquisition of TetraSun. The '074 Patent is directed to high-efficiency solar cell structures and methods of manufacture, specifically covering processes for manufacturing "tunnel oxide passivated contact" (TOPCon) crystalline silicon photovoltaic cells. First Solar claims that Canadian Solar practices the methods of the '074 Patent through the manufacture of TOPCon solar cells and modules, which are then imported into and sold in the United States.

This litigation is proceeding in the District of Delaware, a frequent venue for patent cases, particularly for disputes involving companies incorporated in Delaware, which includes a significant portion of major U.S. technology and pharmaceutical firms. The court is known for its experienced patent bench, with judges well-versed in claim construction and complex technical litigation. The case is assigned to the Honorable Jennifer L. Hall. The dispute is notable due to its focus on TOPCon solar cell technology, which is a significant and competitive area in the global solar industry. The case has also been linked to Inter Partes Review (IPR) proceedings; Canadian Solar (USA) Inc. had previously petitioned for IPR of US Patent 9130074 (IPR2025-01130), which the USPTO Director denied, confirming the strength of First Solar's patent portfolio related to TOPCon technology. This IPR denial, along with similar rejections for petitions by other solar manufacturers like JinkoSolar and Mundra Solar, indicates a strong position for First Solar in its efforts to enforce its TOPCon patents. First Solar has announced its intention to license and enforce its TOPCon patent portfolio, initiating infringement investigations against several leading crystalline silicon solar cell manufacturers.

First Solar, Inc. initiated patent infringement litigation against Canadian Solar Inc. in the U.S. District Court for the District of Delaware, centering on U.S. Patent 9,130,074, which covers TOPCon solar cell technology. The case remains active.

Here are the key legal developments in chronological order:

• 2025-05-09: Complaint Filed
  First Solar, Inc. filed a patent infringement lawsuit against Canadian Solar Inc. in the U.S. District Court for the District of Delaware, Case No. 1:25-cv-00582, alleging infringement of U.S. Patent No. 9,130,074. The complaint asserted that First Solar's '074 patent, which relates to high-efficiency TOPCon solar cell structures and manufacturing methods, was being infringed by Canadian Solar's TOPCon solar modules.

• 2025-08-22: Canadian Solar Files IPR Petition (IPR2025-01432)
  Canadian Solar (USA) Inc. filed an Inter Partes Review (IPR) petition with the U.S. Patent Trial and Appeal Board (PTAB) against First Solar's U.S. Patent No. 9,130,074. This petition, assigned IPR2025-01432, sought to invalidate claims 1-8 of the '074 patent.

• 2025-09-15: Joint Letter Regarding Discovery and Pleadings
  First Solar and Canadian Solar jointly submitted a letter to Judge Jennifer L. Hall, addressing disagreements concerning the timing for amending pleadings to add new parties and the phasing and scope of email discovery. This indicates that discovery was underway and initial responsive pleadings, such as an answer, had likely been filed prior to this date, though specific dates for those filings are not readily available in public summaries.

• 2025-12-18: USPTO Denies Canadian Solar's IPR Petition
  The Director of the United States Patent and Trademark Office (USPTO) denied Canadian Solar's IPR petition (IPR2025-01432) for U.S. Patent No. 9,130,074. The denial was a discretionary one, reinforcing First Solar's intellectual property rights.

• Present Posture (as of 2026-05-25): Ongoing Litigation
  The patent infringement lawsuit (1:25-cv-00582) remains pending in the United States District Court for the District of Delaware. No information regarding claim construction (Markman) outcomes, summary judgment motions, trial events, or a final disposition has been publicly reported, other than the case continuing to progress in the district court.

Note on IPRs:
While the prompt mentioned IPR2025-01130 as Canadian Solar's IPR, public records indicate that IPR2025-01130 was filed by JinkoSolar Holding Co Ltd against the same patent, and was also discretionarily denied by the USPTO on November 20, 2025. Canadian Solar's IPR was IPR2025-01432.

First Solar, Inc. is represented by lead counsel from Cravath, Swaine & Moore LLP.

The identified counsel of record for the plaintiff is:

• Name: Keith R. Hummel
  • Role: Lead Counsel
  • Firm: Cravath, Swaine & Moore LLP
  • Office Location: New York, NY
  • Relevant Patent Litigation Experience: Mr. Hummel is a member of Cravath's Litigation Department and Co-Chair of its Intellectual Property Practice, with over thirty years of experience. He has extensive experience litigating complex commercial, intellectual property, and antitrust disputes for both plaintiffs and defendants across diverse fields, including biotechnology, pharmaceuticals, medical devices, home automation, computer hardware and software, and telecommunications. Notable cases include winning a jury verdict for Amgen in a patent infringement case in Delaware federal court and representing Amgen in litigation concerning the introduction of a biosimilar under the Biologics Price Competition and Innovation Act (BPCIA). He also successfully resolved multi-jurisdictional patent and contractual litigation for Alarm.com.

Despite extensive searching, specific local counsel appearing for First Solar, Inc. in District of Delaware case 1:25-cv-00582 could not be definitively identified without direct access to the court's docket for appearance filings. Delaware firms such as Morris, Nichols, Arsht & Tunnell LLP and Richards, Layton & Finger P.A. are frequently engaged as local counsel in patent litigation in the District of Delaware, but no specific attorneys from these firms were explicitly linked to First Solar in this particular case in the available public search results.