REC Solar v. Hanwha Solutions: Federal Circuit Affirms Solar Cell Patent Unpatentable
REC Solar Pte. Ltd. appealed an unpatentability ruling over US10749060B2, covering solar cell assembly technology, against Hanwha Solutions Corp. The Federal Circuit affirmed the finding across a 707-day appellate proceeding, leaving the patent cancelled and closing off further challenge at this court level.
Federal Circuit closes the door on REC Solar’s photovoltaic patent
REC Solar Pte. Ltd., a Singapore-based solar technology company, filed this appeal at the U.S. Court of Appeals for the Federal Circuit on February 14, 2023, challenging an underlying determination that US10749060B2 — a patent covering solar cell assembly technology — was unpatentable. The respondent, Hanwha Solutions Corp., a South Korean energy and chemicals conglomerate with significant solar manufacturing operations, successfully defended the invalidity finding at the lower level.
On January 21, 2025, the Federal Circuit issued its affirmance, finding REC Solar’s remaining arguments unpersuasive and upholding the unpatentability ruling. The basis of termination is recorded as ‘Unpatentable,’ consistent with a patent cancellation following an inter partes or post-grant review proceeding. The affirmance means US10749060B2 is cancelled and no longer enforceable, removing it from REC Solar’s IP arsenal against Hanwha Solutions or any third party.
The 707-day duration suggests a substantive appellate briefing cycle, and the court’s terse dismissal of REC’s remaining arguments as ‘unpersuasive’ typically signals the panel found the lower tribunal’s factual and legal analysis well-grounded. What remains unknown from the public record is the precise prior art basis for unpatentability and whether REC Solar has parallel patent family members that could sustain enforcement in the solar cell assembly space going forward.
Filing to Unpatentable in 707 days
707-day appellate proceeding — above the Federal Circuit median for patent validity appeals
Federal Circuit affirms: what the ruling means for both parties
Affirmance means the lower ruling stands without reversible error
When the Federal Circuit ‘affirms,’ it is holding that the tribunal below committed no reversible legal or factual error sufficient to overturn its decision. The court reviewed the unpatentability determination — likely from the Patent Trial and Appeal Board — and found REC Solar’s challenges to that ruling unpersuasive. The original cancellation of US10749060B2 is now judicially confirmed.
No reversible error foundUS10749060B2 is cancelled — REC Solar loses this enforcement asset
For REC Solar, the affirmance is a definitive loss. US10749060B2 can no longer be asserted in litigation or licensing negotiations. Unless REC Solar holds continuation or divisional patents in the same family covering similar solar cell assembly claims, its ability to enforce this specific technology position against Hanwha Solutions and other solar manufacturers is extinguished.
Patent cancelled — unenforceableHanwha Solutions secures freedom to operate without this patent overhead
Hanwha Solutions prevailed at every level of this dispute. With the Federal Circuit affirmance, the company — a major solar cell and module manufacturer — can operate in the solar cell assembly space without risk of infringement claims under US10749060B2. The ruling also raises the bar for any future REC Solar attempt to re-assert equivalent claims in this technology domain.
FTO strengthened for HanwhaSolar sector: one fewer patent barrier in crystalline cell assembly
The cancellation of US10749060B2 is commercially significant for the broader photovoltaic manufacturing industry. Competitors operating in the crystalline silicon solar cell assembly space — including module makers and cell fabricators — face one fewer active patent threat. For IP strategists tracking REC Solar’s portfolio, the ruling suggests scrutinising the remaining family members around this application number (US14/900942) for potential vulnerability.
Reduced IP barrier in solar manufacturingFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | REC Solar Pte., Ltd. | Company | Solar technology company — holder of US10749060B2 (solar cell assembly)Search in Eureka ↗ |
| Defendant | Hanwha Solutions Corp. | Company | Hanwha Solutions Corp. — South Korean energy and chemicals conglomerate, solar manufacturerSearch in Eureka ↗ |
| Plaintiff counsel | Andrea Grace Klock Mills At | Attorney | Counsel for REC Solar Pte., Ltd.Search in Eureka ↗ |
| Plaintiff counsel | Anthony A. Hartmann | Attorney | Counsel for REC Solar Pte., Ltd.Search in Eureka ↗ |
| Plaintiff counsel | Forrest Alexander Jones | Attorney | Counsel for REC Solar Pte., Ltd.Search in Eureka ↗ |
| Plaintiff counsel | James R. Barney | Attorney | Counsel for REC Solar Pte., Ltd.Search in Eureka ↗ |
| Plaintiff counsel | Mareesa Arnita Frederick | Attorney | Counsel for REC Solar Pte., Ltd.Search in Eureka ↗ |
| Plaintiff law firm | Finnegan, Henderson, Farabow, Garrett & Dunner, LLP | Law Firm | Representing REC Solar Pte., Ltd.Search in Eureka ↗ |
| Defendant counsel | David Langdon Cavanaugh | Attorney | Counsel for Hanwha Solutions Corp.Search in Eureka ↗ |
| Defendant counsel | Jason Kipnis | Attorney | Counsel for Hanwha Solutions Corp.Search in Eureka ↗ |
| Defendant counsel | Mark D. Selwyn | Attorney | Counsel for Hanwha Solutions Corp.Search in Eureka ↗ |
| Defendant counsel | Nora N. Xu | Attorney | Counsel for Hanwha Solutions Corp.Search in Eureka ↗ |
| Defendant counsel | Robert J. Gunther Jr. | Attorney | Counsel for Hanwha Solutions Corp.Search in Eureka ↗ |
| Defendant law firm | Wilmer Cutler Pickering Hale & Dorr LLP | Law Firm | Representing Hanwha Solutions Corp.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The Federal Circuit’s affirmance in Case No. 23-1508 is economical but conclusive: the panel considered all of REC Solar’s arguments and found none sufficient to disturb the underlying unpatentability ruling. Under the applicable appellate standard, PTAB legal determinations are reviewed de novo while factual findings — such as the scope of prior art and motivation to combine — attract substantial evidence deference. The court’s framing that arguments were ‘unpersuasive’ without extended analysis typically indicates the panel found the PTAB record well-supported, leaving REC Solar with no viable path to reinstate US10749060B2.
US10749060B2 — Solar cell assembly technology
US10749060B2 was filed under application number US14/900942 and granted to REC Solar Pte. Ltd., covering solar cell assembly technology in the photovoltaic domain. The patent relates to the structural configuration or fabrication methodology of solar cells — most likely crystalline silicon-based, given REC Solar’s core technology focus. The patent’s assignee is a well-known manufacturer of high-efficiency solar cells, making this asset part of a commercially significant portfolio aimed at protecting proprietary cell architecture.
In the competitive solar manufacturing landscape, solar cell assembly patents carry significant commercial weight — they can restrict competitor manufacturing processes and support licensing programmes across a global supply chain. Hanwha Solutions’ decision to challenge this patent through post-grant proceedings, and to successfully defend that challenge through to the Federal Circuit, suggests the patent was perceived as a genuine competitive threat. With the patent now cancelled, the underlying technology claims enter a more open competitive environment, though related family patents may still define enforceable boundaries.
Should you run an FTO against US10749060B2 and its patent family?
Any company engaged in solar cell assembly manufacturing, crystalline silicon cell fabrication, or photovoltaic module integration should assess whether live sibling patents from the US14/900942 family remain in force. While US10749060B2 is cancelled, patent families routinely include continuations and divisionals with overlapping claim scope. R&D teams developing next-generation solar cell architectures face particular exposure if those designs fall within claims of surviving family members.
PatSnap Eureka’s FTO Search Agent can map the full patent family around US14/900942, identify granted and pending siblings, and flag claim language that intersects with specific solar cell assembly workflows. For product teams preparing technology launches in the photovoltaic sector, a Eureka-assisted FTO provides a structured, audit-ready clearance analysis that accounts for both REC Solar’s remaining portfolio and the broader competitive patent landscape around solar cell assembly.
Run a freedom-to-operate analysis on US10749060B2 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit IPR appeals in solar and photovoltaic patents
Explore Federal Circuit decisions affirming PTAB unpatentability rulings in solar cell and photovoltaic technology — cases most relevant to the REC Solar v. Hanwha dispute.
What this case signals for the photovoltaic IP landscape
The affirmance confirms PTAB-level patent cancellations in solar tech are holding up at the Federal Circuit — a meaningful signal for enforcement and FTO strategy.
PTAB cancellations in solar cell tech are surviving Federal Circuit scrutiny
The Federal Circuit’s terse affirmance — dismissing all remaining REC Solar arguments as unpersuasive — suggests the PTAB’s unpatentability analysis was well-constructed. Companies holding solar cell assembly patents should audit claim scope and prior art exposure before asserting, as a successful IPR challenge is now demonstrably durable on appeal.
Hanwha Solutions’ IPR strategy sets a replicable precedent for solar manufacturers
Hanwha Solutions’ successful defence through to Federal Circuit affirmance demonstrates that well-resourced solar manufacturers can neutralise competitor patents via post-grant review. For in-house counsel at photovoltaic companies facing infringement assertions, this case supports an IPR-first response strategy, particularly for patents with broad solar cell assembly claims.
REC v Hanwha — key questions answered
The Federal Circuit affirmed the unpatentability of US10749060B2 on January 21, 2025. REC Solar’s appeal of the lower invalidity/cancellation ruling was unsuccessful — the court found all remaining arguments unpersuasive, confirming the patent’s cancellation.
The patent at issue is US10749060B2, filed under application number US14/900942 and held by REC Solar Pte. Ltd. It covers solar cell assembly technology in the photovoltaic domain. The patent was found unpatentable at the underlying proceeding level, and that finding was affirmed by the Federal Circuit.
The affirmance confirms the patent is cancelled and unenforceable. REC Solar cannot assert US10749060B2 in infringement litigation or licensing against any party. Companies in the solar cell assembly space should still audit related family members from the US14/900942 application for potentially surviving claims.
REC Solar was represented by Finnegan, Henderson, Farabow, Garrett & Dunner, LLP, with attorneys including James R. Barney and Mareesa Arnita Frederick among counsel of record. Hanwha Solutions was represented by Wilmer Cutler Pickering Hale & Dorr LLP, with counsel including Mark D. Selwyn and Robert J. Gunther Jr.
The appeal ran for 707 days, from the filing date of February 14, 2023 to the decision date of January 21, 2025. This duration is consistent with a fully briefed Federal Circuit patent validity appeal and suggests substantive argument was presented, though the panel ultimately found none of REC Solar’s arguments sufficient to reverse the lower ruling.
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