Solid Oxide Fuel Cell Patents: Leaders, Trends & White Space 2026
- Filing has cooled since its 2017 peak. 286 families in 2017 fell to a 2022 midpoint of 173, and the newest years are still filling in as publications lag filing.
- One IPC subclass dominates the corpus. H01M accounts for 7,125 of 7,143 records, with ceramics (C04B) and electrolysis (C25B) as the largest secondary clusters.
- Momentum has gone quiet at the top. Several of the most active historical filers, including Bloom Energy and the Technical University of Denmark, show zero filings in the latest year.
Filing growth compares 2021 (184 records) with 2024 (92) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 7,143 records in scope (CR5), not by the ranked leaders only.
What the SOFC patent record actually shows
Solid oxide fuel cell systems patenting concentrates almost entirely inside H01M — batteries, cells and fuel cells — with 7,125 of 7,143 records touching that subclass. The next-largest clusters sit in ceramics processing (C04B) and electrolytic production (C25B), which tracks with SOFC’s dual identity as both a fuel cell and, reversed, an electrolyser. Filing activity peaked in 2017 at 286 families and has trended down through the 2022 midpoint of 173, a pattern more consistent with a maturing, consolidating field than an emerging one.
Publication lags filing by roughly eighteen months, so the last one to two years in any trend undercount true filing activity. That caveat matters here: several long-standing filers register zero output in the most recent year, which could reflect genuine pullback, portfolio consolidation, or simply cases still working through the publication pipeline.
Filing trend and technology composition
Two views of the same corpus: how filing volume has moved year over year, and how that volume splits across the IPC subclasses that define the technical scope of SOFC systems.
A field past its filing peak
286 families published in 2017, the high point in the window. By the 2022 midpoint the annual count had fallen to 173, and the count for the most recent partial year sits at 14 — understated by the publication lag but consistent with a multi-year decline rather than a single soft year.
Claim space is concentrated, not distributed
H01M carries 7,125 of 7,143 records — this is fundamentally a fuel-cell-and-battery-class filing corpus. C04B (503), C25B (430) and C01B (281) form a secondary tier tied to ceramic electrolyte/electrode materials and related electrochemical production, while coating processes (B05D, C23C) and catalysis/separation (B01J, B01D) appear only as smaller supporting clusters.
Shares are the percentage of the 7,143 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Solid Oxide Fuel Cell Systems with Eureka
This page is one run against one query. Ask Eureka your own question about solid oxide fuel cell systems and every answer comes back with the patent numbers behind it.
Try EurekaThe prior art every new filing is measured against
Metal oxide-yttria stabilized zirconia composite and solid oxide fuel cell using the same
Disclosed is a metal oxide-yttria stabilized zirconia composite, including 25˜75 wt % of a metal oxide-3 mol % yttria stabilized zirconia composite, and 75˜25 wt % of a metal oxide-8 mol % yttria stabilized zirconia composite. A solid oxide fuel cell is also provided, which includes the metal oxide-yttria stabilized zirconia composite as an anode layer or a support layer of an anode layer.Filed by Samsung Electro-Mechanics, this record narrows the YSZ composite window by mol % yttria content and by weight ratio between two grades — a claim style that later anode-support filings have had to work around rather than through.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5741605A | Solid oxide fuel cell generator with removable modular fuel cell stack configurations | 341 |
| 2 | US20050164051A1 | High temperature fuel cell system and method of operating same | 327 |
| 3 | US20040202914A1 | Co-production of hydrogen and electricity in a high temperature electrochemical system | 310 |
| 4 | US5601937A | Hydrocarbon reformer for electrochemical cells | 235 |
| 5 | US20030054215A1 | Compact integrated solid oxide fuel cell system | 221 |
| 6 | US6485852B1 | Integrated fuel reformation and thermal management system for solid oxide fuel cell systems | 218 |
| 7 | US20020142208A1 | Energy efficient gas separation for fuel cells | 204 |
| 8 | US5968680A | Hybrid electrical power system | 202 |
| 9 | WO2000045457A2 | MEMS-based thin-film fuel cells | 196 |
| 10 | US5763114A | Integrated reformer/CPN SOFC stack module design | 195 |
Citation counts favour older filings simply because they have had longer to accumulate citations inside this corpus — read them as a signal of influence on later filers, not as a ranking of present-day importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Four patterns stand out once volume, geography and citation weight are read together.
The peak has passed
Annual filings fell from a 2017 high of 286 to a 2022 midpoint of 173, and the most recent year shows only 14 — a figure the publication lag will revise upward but unlikely to reverse the multi-year decline.
Almost everything is H01M
The corpus is overwhelmingly classified under batteries and fuel cells, with ceramics (503) and electrolytic production (430) as the only secondary clusters of real size.
US and Europe lead, PCT is a secondary funnel
The United States and the EPO together account for more receiving-office activity than the rest of the tracked jurisdictions combined, with WIPO PCT filings serving as a bridge before national phase.
Collaboration is narrow and concentrated
Only ten co-assignee pairs appear in the dataset, and the strongest — a university and a fuel-cell specialist — share 23 families, far ahead of the next pairs.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to solid oxide fuel cell systems, with the prior art for and against each one.
Who is filing, and who has stopped
Historical volume and current momentum tell different stories. Several names with the deepest filing history show no output in the latest tracked year — a signal worth checking against private roadmaps before assuming exit.
A leading filer has gone quiet
Bloom Energy shows zero filings in the most recent tracked year against a -100% year-over-year change, a sharp drop from its historical filing base.
Academic filing has also paused
The Technical University of Denmark, the anchor of the strongest co-assignee pair in the dataset (23 shared families with Topsoe Fuel Cell), likewise shows no filings in the latest year.
University-industry pairing leads joint filing
The Technical University of Denmark and Topsoe Fuel Cell form the strongest co-assignee relationship in the corpus, well ahead of the Bloom Energy pairings that follow.
| Assignee | Recent year | YoY |
|---|---|---|
| Bloom Energy Corporation | 0 | -100% |
| Ceres Intellectual Property Company Limited | 0 | — |
| Saint-Gobain Ceramics & Plastics, Inc. | 0 | — |
| Technical University of Denmark | 0 | -100% |
| Haldor Topsoe A/S | 0 | — |
| Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA) | 0 | -100% |
| Delphi Technologies IP Limited | 0 | — |
| Versa Power Systems, Ltd. | 0 | — |
Where to take this analysis
The dataset points to a field with concentrated core claims and a shrinking but still active filing base. These are the next steps worth taking before committing a filing budget.
Map the anode-support and interconnect sub-claims
The gap between H01M's dominance and the smaller ceramics and coating clusters suggests specific claim territory around anode-support microstructure and interconnect coatings is less crowded than the headline volume implies.
Explore sub-claim mapping in EurekaWatch the quiet leaders for renewed activity
Bloom Energy, the Technical University of Denmark and several other historically active filers show zero output in the latest year — worth monitoring given the eighteen-month publication lag before treating this as exit.
Track assignee momentum in EurekaCheck citation-heavy prior art before drafting
The most-cited records in this corpus date back to earlier SOFC system architecture; any new anode, interconnect or stack claim should be checked against them before drafting.
Run a prior-art check in EurekaCommon questions about SOFC patenting
This dataset tracks 7,143 patent families published between 2015 and mid-2026 that combine SOFC-related terms with claim language around yttria-stabilized zirconia, interconnects, anode support, operating temperature or thermal cycling. That figure counts families, which is the fairer unit than raw document counts because it removes duplication from continuations and multi-jurisdiction refiling of the same invention. The true total for solid oxide fuel cell technology broadly, without the specific claim-language filter used here, would be larger.
Filing has slowed considerably from its peak. Annual publications reached 286 in 2017, fell to 173 by the 2022 midpoint, and show only 14 in the most recent partial year. Because publication lags actual filing by around eighteen months, the last one to two years will revise upward, but the multi-year direction from 2017 onward is clearly downward rather than flat.
Filing activity concentrates among a small group of specialist fuel-cell firms, ceramics manufacturers and research universities, with a long tail of smaller filers behind them. Several of the historically largest filers, including Bloom Energy and the Technical University of Denmark, show zero output in the latest tracked year, which makes current momentum a separate question from historical volume. Anyone assessing competitive position should look at both the ranking and the recent-year trend rather than either alone.
The corpus is dominated by IPC subclass H01M — batteries, cells and fuel cells — which covers 7,125 of the 7,143 records. Ceramics processing (C04B) and electrolytic production of compounds (C25B) form the next largest clusters, reflecting SOFC's overlap with solid electrolyte materials and reversible electrolysis operation. Smaller clusters in coating processes and catalysis suggest these supporting technologies are patented far less densely than the core cell and stack architecture.
The gap between the dominant H01M volume and the much smaller ceramics, coating and catalysis clusters points to under-claimed territory in areas like anode-support microstructure grading, interconnect coating durability under thermal cycling, and reversible SOFC/electrolysis dual-mode claims. High filing density in H01M means core cell and stack claim space is occupied, not that these adjacent branches are technically exhausted. A freedom-to-operate review focused on the smaller IPC clusters is likely to surface more open claim space than a review of the core subclass alone.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.