The US Patent and Trademark Office (USPTO) has denied three applications challenging the validity of patents held by US CdTe thin-film manufacturer First Solar pertaining to its tunnel oxide passivated contact (TOPCon) technology.
The inter partes review applications were filed individually by Chinese manufacturer JinkoSolar, multinational firm Canadian Solar and Indian installer Mundra Solar and declined on 20 November, 11 December and 18 December last year, respectively, according to First Solar.
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Munda Solar sought to challenge First Solar’s patent number 9,666,732, while the other companies challenged patent number 9,130,074. Both relate to methods of manufacturing TOPCon crystalline silicon (c-Si) solar cells and, according to First Solar, date back to its 2013 acquisition of start-up TetraSun.
First Solar’s executive vice president, general counsel and secretary, Jason Dymbort, welcomed the USPTO’s decision, saying that the length of time for which First Solar has owned these patents contributed to the office’s decision.
“We believe that this is consistent with USPTO’s ‘Settled Expectations’ doctrine, which is underpinned by the principle that the longer a patent has been in force, the stronger and more settled the patent owner’s expectations should be,” said Dymbort. “The patents at issue in each of these matters were issued in 2015 and 2017, respectively, long before each of these manufacturers’ petitions were filed.”
First Solar also noted that it has pending lawsuits against all three claimants, alleging infringement of its patents, in the District Court for the District of Delaware.
In response, a JinkoSolar spokesperson said that the decision is “divorced from the merits of our challenge”, and expressed optimism that a more thorough investigation would yield different results.
“The USPTO’s decision not to institute review was based solely on discretionary grounds, which are wholly divorced from the merits of our challenge,” the spokesperson told PV Tech this week. “While we respectfully disagree with that discretionary denial, we remain confident that when the Federal District Court considers a full, merits-based review, it will find that the First Solar patent involved is invalid.”
The company first warned of possible infringements of its TOPCon and other c-Si patents back in 2024 and stated its intention to instigate legal challenge against any companies found to be using its IP without a licence. It subsequently launched infringement challenges against JinkoSolar, Canadian Solar, JA Solar, LONGi and Trina Solar.
Due in large part to First Solar’s fierce protection of its TOPCon patents, the cell technology has been slow to take off in the US, but start-up Talon PV is now seeking to become the first US company to manufacture TOPCon cells at commercial scale under licence from First Solar.
Last year, Talon PV’s CEO Adam Tesanovich told PV Tech Premium that First Solar had been “almost a big brother” to Talon PV in bringing its plans for TOPCon production to fruition.
This article was updated to include the comment from JinkoSolar after initial publication.
