The Patent Trial and Appeal Board (PTAB) of the US Patent and Trademark Office (USPTO) has partially ruled against solar manufacturer Maxeon in several of its allegations of patent infringement by Canadian Solar.
The rulings in favour of Canadian Solar pertain to patents 8,222,516 B2 and 8,878,053 B2, which are both related to “front contact solar cell with formed emitter”.
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For both patents, the PTAB stated that Canadian Solar established “by a preponderance” that the patents are unpatentable on several claims.
Colin Parkin, president of Canadian Solar, said: “The final decision issued by the USPTO once again affirms that Canadian Solar’s technology and legal teams have always respected and placed great importance on protecting both our own and our peers’ intellectual property. At the same time, we firmly oppose the misuse or weaponisation of patents—particularly those lacking patentability or practical value—which can distort competition and impede genuine innovation.”
However, a third patent (11,251,315 B2) was ruled against Canadian Solar, and the PTAB stated that the company was not able to show by a preponderance of the evidence that the patent was unpatentable. This third patent is directed to solar cell fabrication techniques to improve solar cell lifetime, passivation and/or efficiency and example solar cells fabricated according to the disclosed techniques.
“Maxeon is currently evaluating this USPTO ruling and the option to appeal in accordance with applicable procedures. We believe we have credible legal grounds to seek reversal of the decision, and of note is the fact that the USPTO’s ruling upheld the validity of one of our TOPCon patent claims. Maxeon will continue to defend our intellectual property rights across our broad portfolio of solar IP, and we do not expect this development to change the Company’s long-term strategy,” said a spokesperson for Maxeon.
It is worth highlighting that a year earlier, the infringement allegations for that same patent (11,251,315 B2) were dismissed with prejudice in the US District Court for the Eastern District of Texas at the beginning of June 2025, while weeks later, a motion to stay pending inter partes review (IPR) was granted for the asserted claims for the three aforementioned patents.
Moreover, all three patents are also part of other district court proceedings against fellow solar manufacturers REC Solar and Hanwha (Solutions and Energy).
Maxeon had initiated a TOPCon infringement lawsuit against Canadian Solar in March 2024.
