Solid Oxide Electrolysis (SOEC) Patent Landscape
The SOEC patent field is heavily concentrated at the top: two European incumbents — CEA and Haldor Topsøe — together account for the majority of the largest filers’ combined output, with all other players trailing at a significant distance. The field is still expanding on a multi-year basis, though annual volume has eased from its 2023 peak, and adjacent branches in downstream synthesis and separation remain comparatively sparse.
Two European incumbents dominate a highly concentrated field
CEA (Commissariat à l’Énergie Atomique et aux Énergies Alternatives) holds the top position in the SOEC applicant ranking with 228 patent families, followed closely by Haldor Topsøe with 192 patent families. Every other filer in the top twenty holds fewer than 25 patent families, marking an abrupt drop-off after the leading pair.
The top five filers collectively account for 63% of the hundred largest filers’ combined total — a high concentration ratio indicating that two or three incumbents set the technical agenda. Mitsubishi Heavy Industries ranks third with 22 patent families, while Osaka Gas and Saudi Arabian Oil Company each hold 12, illustrating the scale of the tier gap.
| # | Applicant | Patent families | Share |
|---|---|---|---|
| 1 | French Alternative Energies and Atomic Energy Commission (CEA) | 228 | |
| 2 | Topsoe A/S (formerly Haldor Topsøe) | 192 | |
| 3 | Mitsubishi Heavy Industries, Ltd. | 22 | |
| 4 | Osaka Gas Co., Ltd. | 12 | |
| 5 | Saudi Arabian Oil Company (Saudi Aramco) | 12 | |
| 6 | Niterra Co., Ltd. | 11 | |
| 7 | Mitsubishi Electric Corporation | 10 | |
| 8 | Versa Power Systems, Ltd. | 10 | |
| 9 | Toyota Central R&D Labs., Inc. | 8 | |
| 10 | Precision Combustion, Inc. | 8 |
| # | Applicant | Patent families | Share |
|---|---|---|---|
| 11 | Mitsubishi Power, Ltd. | 7 | |
| 12 | Bloom Energy Corporation | 7 | |
| 13 | Aisin Corporation | 7 | |
| 14 | University of Yamanashi | 6 | |
| 15 | Shanghai Institute of Applied Physics, Chinese Academy of Sciences | 6 | |
| 16 | Honda Motor Co., Ltd. | 5 | |
| 17 | North China Electric Power University | 5 | |
| 18 | Infinium Technology LLC | 5 | |
| 19 | Toshiba Corporation | 5 | |
| 20 | Guangzhou Power Supply Bureau, Guangdong Power Grid | 5 |
CEA’s and Topsøe’s dominance signals that challengers entering today face significant prior-art density in core cell and stack architectures; differentiation is more viable in system integration, specific electrolysis routes, or downstream processing steps where the leaders are less entrenched.
Filing counts for 2024–2026 are likely understated owing to typical 18–24 month publication lags; apparent recent softening should not be read as a demand signal until those cohorts mature. Longer-window growth, applicant concentration, and technology-route coverage are therefore more reliable signals than the latest-year bar alone.
Multi-year growth with a 2023 peak; electrolytic production dominates the technology mix
The annual filing trend and the IPC technology composition together reveal a field that surged between 2021 and 2023 and is now in a consolidation phase, with core electrolytic-production classes dominating but several downstream branches remaining lightly covered.
Annual filing trend
Filings rose from 27 families in 2020 to a peak of 116 in 2023, representing an 88% increase in the recent three-year window versus the prior period. The 2024 and 2025 counts (87 and 66 respectively) reflect both natural moderation from a high base and known publication lag; the 2026 figure of 6 is effectively incomplete. The overall picture is one of a field that expanded sharply from 2021 onward and has not yet reverted to pre-surge levels.
↗ Hover for values · click a bar to ask EurekaTechnology composition
C25B (electrolytic production of compounds) is the dominant branch by a wide margin, reflecting that most SOEC patent activity centers on cell, stack, and process design. H01M (batteries, cells, and fuel cells) is the second-largest class, capturing reversible SOEC/SOFC work. Branches such as C01B (non-metallic elements and inorganic compounds), B01D (separation), C07C (acyclic and carbocyclic compounds), and C01C (ammonia and nitrogen compounds) appear at substantially lower shares, signaling that downstream synthesis and gas-processing integration remain comparatively sparse.
↗ Hover for values · click a bar to ask EurekaHighly cited patent families surfaced by the query
Citation-heavy patent families returned by the query. Use this section as citation context, not as a curated list of the most topic-specific patents.
Microwave-assisted Solid Oxide Electrolysis Cell (…
A method of enhancing an electrolysis reaction in a solid oxide electrolysis cell (SOEC) for hydrogen production featuring: providing a water vapor stream to a cathode chamber of a SOEC; wherein the SOEC has an cathode chamber and an anode chamber, wherein the cathode chamber contains a catalyst; and wherein the catalyst has one or more conducting oxides… (excerpt from the patent abstract)
| # | Patent | Citations |
|---|---|---|
| 1 | A process for producing co from co 2 in a solid ox… | 125 |
| 2 | System for high-temperature reversible electrolysi… | 83 |
| 3 | Heat management method in a high-temperature steam… | 81 |
| 4 | Elementary unit for reactor performing water elect… | 53 |
| 5 | Method for operating an SOEC-type stack reactor fo… | 53 |
| 6 | Method of startup mode or standby mode operation o… | 38 |
| 7 | 高純度の一酸化炭素を製造するための装置 | 33 |
| 8 | Control device and control method of hydrogen prod… | 31 |
Ranked by total forward citations. Citation counts favour older and broadly cited patent families, and broad or adjacent patents may appear when they match the search scope. Treat this section as citation context, not as a curated list of the most topic-specific patents. Some patent titles may be shown in their original, non-English language where an accurate translation could not be guaranteed.
What the competitive structure means for R&D investment
Four structural features of the SOEC landscape — maturity, concentration, collaboration, and geography — each carry direct implications for where new entrants or challengers can most efficiently deploy R&D resources.
Growth stage, easing from a 2023 peak
The field carries a Growth stage designation: the recent three-year filing window sits 88% above the prior three-year window on a multi-year basis, confirming sustained expansion. However, annual volume has eased from the 2023 peak of 116 families, and publication lag means 2024–2025 data are not yet fully visible. Entrants should expect a maturing prior-art landscape in core cell and stack technologies while system-level and downstream integration remain less saturated.
Growth · post-2023-peakExtreme two-player concentration at the top
CEA and Haldor Topsøe together dwarf all other filers; the tier gap between rank two and rank three is nearly tenfold (192 vs. 22 patent families). The top five filers hold 63% of the hundred largest filers’ combined total. This level of concentration means the incumbents’ patent portfolios create broad freedom-to-operate challenges in core SOEC architecture, making niche differentiation — particularly in downstream synthesis routes or system integration — the more defensible entry point for challengers.
High concentrationCollaboration is limited; Mitsubishi group is the most active co-filer
The most active co-filing pair in the corpus is Mitsubishi Heavy Industries and Mitsubishi Power, which have jointly filed 7 patent families — likely reflecting shared development on large-scale SOEC integration projects. Saudi Arabian Oil Company and Saudi Aramco Services Company have co-filed once. Beyond these two pairings, cross-entity collaboration is not prominent, suggesting the field is largely prosecuted through independent corporate pipelines rather than consortia or university–industry alliances.
Limited ecosystem collaborationChina, US, EPO, and PCT nearly tied; Japan and Korea are secondary hubs
China leads jurisdiction filings, closely followed by the United States, WIPO PCT, and Europe (EPO) — all four sitting within a narrow band. Japan and South Korea form a clear second tier. The geographic spread signals that SOEC is being prosecuted as a globally strategic technology, and freedom-to-operate analysis must cover at minimum these four primary jurisdictions. The near-parity between China and the trilateral offices also implies that Chinese domestic players and state-backed institutes are actively building local portfolios.
Multi-jurisdictionGo beyond the landscape: Eureka’s TRIZ Solution agent breaks down an R&D problem and returns patented concept solutions, each with a technical approach and cited patent & literature evidence.
| Applicant | Collaborator | Co-filings |
|---|---|---|
| Mitsubishi Heavy Industries, Ltd. | Mitsubishi Power, Ltd. | 7 |
| Saudi Arabian Oil Company (Saudi Aramco) | Saudi Aramco Services Company | 1 |
Co-filing pairs, ranked by the number of jointly-filed patent families.
CEA and Haldor Topsøe lead across complementary technical routes
The two incumbent leaders are roughly matched in scale but differ in technical emphasis: CEA concentrates heavily on cell and fuel-cell fundamentals, while Topsøe is more narrowly focused on electrolytic process and compound production. Both are still actively filing with meaningful recent momentum.
CEA (Commissariat à l’Énergie Atomique)
CEA holds 228 patent families, the largest portfolio in the corpus, with recent filings up 76% versus the prior period — confirming continued aggressive prosecution. The portfolio spans fuel-cell fundamentals (H01M 8), electrolytic cell design (C25B 9), and process/operational methods (C25B 15), reflecting broad coverage across the SOEC value chain. CEA’s depth across all three sub-classes makes it the de facto prior-art anchor for the field.
patent families: 228Haldor Topsøe (now Topsoe A/S)
Haldor Topsøe holds 192 patent families and is filing at a pace 33% above its prior three-year baseline, suggesting sustained R&D investment. Its portfolio is concentrated on electrolytic process methods (C25B 15 and C25B 1) and cell/stack design (C25B 9), with less emphasis on the fuel-cell reversibility branch that CEA covers heavily. This narrower focus makes Topsøe the dominant reference point specifically for SOEC stack process optimization and hydrogen/syngas production routes.
patent families: 192| Applicant | Recent (3 yrs) | Trend |
|---|---|---|
| French Alternative Energies and Atomic Energy Commission (CEA) | 67 | ▲ +76% |
| Topsoe A/S (formerly Haldor Topsøe) | 77 | ▲ +33% |
| Mitsubishi Heavy Industries, Ltd. | 16 | ▲ new entrant |
| Saudi Arabian Oil Company (Saudi Aramco) | 4 | ▲ new entrant |
| Osaka Gas Co., Ltd. | 7 | ▲ new entrant |
| Niterra Co., Ltd. | 3 | ▲ new entrant |
| Versa Power Systems, Ltd. | 1 | ▲ new entrant |
| Mitsubishi Electric Corporation | 10 | ▲ new entrant |
Under-served routes in downstream synthesis and gas separation
Several IPC branches adjacent to the dominant C25B core carry plausible technical relevance to SOEC but show comparatively sparse coverage, suggesting they have not yet attracted systematic patent prosecution relative to their potential role in integrated SOEC systems.
C01C · Ammonia and nitrogen compounds
With only 18 patent records in the corpus, ammonia synthesis via SOEC-derived hydrogen is among the least-covered downstream routes. Electrochemically produced green ammonia is a high-value target for both energy storage and fertilizer decarbonization; the sparse coverage in C01C relative to C25B suggests that most filers are stopping at the hydrogen production step and not extending claims into the synthesis chemistry. A team with SOEC process know-how and nitrogen fixation expertise could find this branch comparatively open.
Search this in Eureka →B01D · Separation processes
B01D covers gas separation and purification — steps that are integral to any SOEC system producing CO, syngas, or high-purity hydrogen at scale. The branch carries 42 patent records against C25B’s 746, a ratio that implies separation integration is underpatented relative to its engineering importance in SOEC deployments. Entrants working on membrane or pressure-swing adsorption integration within SOEC balance-of-plant have room to establish positions here, particularly given the absence of the two dominant incumbents from this branch as a primary focus.
Search this in Eureka →How leaders differ across SOEC technology sub-routes
Route coverage across the main technology branches in the current evidence set.
| Player | C25B 1 · Electrolytic production of compounds | C25B 15 · Electrolytic production of compounds | C25B 9 · Electrolytic production of compounds | H01M 8 · Batteries, cells & fuel cells | C25B 13 · Electrolytic production of compounds |
|---|---|---|---|---|---|
| French Alternative Energies and Atomic Energy Commission (CEA) | Strong · 176 | Strong · 181 | Strong · 182 | Strong · 191 | Emerging · 19 |
| Topsoe A/S (formerly Haldor Topsøe) | Strong · 143 | Strong · 148 | Strong · 105 | Emerging · 21 | Emerging · 15 |
| Mitsubishi Heavy Industries, Ltd. | Strong · 22 | Moderate · 9 | Strong · 22 | Absent | Moderate · 5 |
| Mitsubishi Electric Corporation | Strong · 9 | Strong · 10 | Strong · 8 | Strong · 9 | Moderate · 4 |
| Niterra Co., Ltd. | Strong · 11 | Absent | Strong · 11 | Moderate · 4 | Strong · 9 |
| Precision Combustion, Inc. | Strong · 8 | Strong · 8 | Strong · 8 | Strong · 8 | Absent |
| Saudi Arabian Oil Company (Saudi Aramco) | Strong · 12 | Strong · 7 | Strong · 7 | Absent | Moderate · 5 |
Frequently asked questions
The corpus covers 646 patent families in solid oxide electrolysis, spanning global filings with primary prosecution in China, the United States, WIPO PCT, and Europe (EPO).
CEA leads with 228 patent families, followed by Haldor Topsøe with 192. The next tier — Mitsubishi Heavy Industries (22), Osaka Gas (12), and Saudi Arabian Oil Company (12) — is far smaller, illustrating a pronounced concentration gap at the top of the ranking.
The field is assessed as Growth stage. The recent three-year filing window is 88% above the prior three-year window on a multi-year basis. Annual volume peaked in 2023 at 116 families and has moderated since, though publication lag means 2024–2025 data are not yet fully counted.
China leads with 115 patent records, nearly tied with the United States (113), WIPO PCT (113), and Europe/EPO (112). Japan (68) and Canada (60) form a secondary cluster. This near-parity across the four primary offices means comprehensive freedom-to-operate analysis must cover all of them.
Ammonia and nitrogen compounds (C01C, 18 records), hydrocarbon oils and refining (C10G, 17 records), and acyclic and carbocyclic compounds (C07C, 36 records) are all substantially sparser than the dominant C25B class. Separation processes (B01D, 42 records) are also underrepresented given their engineering importance in SOEC balance-of-plant. These represent adjacent branches that have not yet attracted systematic prosecution.
Among the top filers, CEA shows a 76% increase in recent filings versus its prior three-year baseline, while Haldor Topsøe is up 33%. Mitsubishi Heavy Industries, Mitsubishi Electric, Osaka Gas, Saudi Arabian Oil Company, Niterra, and Versa Power Systems all appear as new entrants in the recent period, though from smaller prior bases.
Ready to map your own SOEC patent landscape?
Join 18,000+ innovators using PatSnap Eureka to map any technology landscape: search 2B+ patents and papers, surface key assignees, and generate a report like this in minutes.
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.