Molten Carbonate Fuel Cell Patents: Top Companies & Filing Trends 2026
- Filings peaked in 2022 at 95 and have declined since, suggesting the core BOP claim space is now largely staked out rather than still forming.
- H01M dominates with 648 of 747 records, while adjacent subclasses like F02C (32) and C23F (28) show comparatively thin coverage of turbine integration and corrosion management.
- Several leading assignees show 0 filings in the latest year and -100% YoY, a momentum pattern worth checking before assuming any single firm still leads active prosecution.
What this landscape covers
Molten carbonate fuel cell (MCFC) balance-of-plant technology spans the fuel processing, thermal management and gas-handling subsystems that sit around the electrochemical stack itself. This dataset pulls 747 patent families published between 2015 and mid-2026 that reference MCFC alongside balance-of-plant, fuel processing subsystem, or thermal management subsystem language in title, abstract or claims. It is a narrower cut than general fuel-cell patenting: it isolates the plumbing, heat integration and gas conditioning around the stack rather than stack chemistry itself.
Filing activity is concentrated in the United States and Europe as receiving offices, with a meaningful WIPO/PCT presence indicating multi-jurisdiction strategies. Because publication typically lags filing by around 18 months, the tail end of the trend line — including the 2026 figure — understates real recent activity.
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Filing trend and technology composition
The trend line and IPC breakdown below show where drafting effort has actually gone, not just where MCFC patents are classified in general.
A filing peak already behind us
Annual filings rose from 33 in 2017 to a peak of 95 in 2022, then declined toward the present. With 2022 sitting at the midpoint of the observed range, the shape reads as flat-to-declining rather than still accelerating — consistent with a technology area where the core architectural claims have already been staked and later filings are increasingly incremental.
Concentration in H01M, thin coverage elsewhere
H01M (batteries, cells & fuel cells) accounts for 648 of 747 records, an overwhelming majority. The next-largest subclasses — C09K materials (81), C25B electrolytic production (42) and B01J catalysis (41) — are each an order of magnitude smaller. F02C gas-turbine integration (32) and C23F corrosion management (28) are thinner still, despite both being technically central to MCFC balance-of-plant operation at scale.
Shares are the percentage of the 747 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Molten Carbonate Fuel Cell Balance of Plant with Eureka
This page is one run against one query. Ask Eureka your own question about molten carbonate fuel cell balance of plant and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited prior art and a representative filing
US9601792B2 — Fuel cell system and method for driving same
Filed by Doosan Heavy Industries & Construction, this patent describes a molten carbonate fuel cell system that separately manages base load and load-following demand using a buffer tank that stores water gas produced by shifting discharge gas, and a driving device actuated from that stored water gas. The stated aim is stable electricity output, better load-following capability, and improved fuel utilisation and energy efficiency together.Granted 2017-03-21.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20050164051A1 | High temperature fuel cell system and method of operating same | 327 |
| 2 | US20150143806A1 | Quintuple-Effect Generation Multi-Cycle Hybrid Renewable Energy System with Integrated Energy Provisioning, S… | 266 |
| 3 | US5541014A | Indirect-fired gas turbine dual fuel cell power cycle | 189 |
| 4 | US20040224193A1 | Method of optimizing operating efficiency of fuel cells | 187 |
| 5 | US6623880B1 | Fuel cell-fuel cell hybrid system | 186 |
| 6 | US20100239924A1 | Fuel cell system with partial recycling of anode exhaust | 133 |
| 7 | US6458477B1 | Fuel cell stacks for ultra-high efficiency power systems | 127 |
| 8 | US20180347406A1 | Quintuple-effect generation multi-cycle hybrid renewable energy system with integrated energy provisioning, s… | 98 |
| 9 | US7422810B2 | High temperature fuel cell system and method of operating same | 94 |
| 10 | US6083636A | Fuel cell stacks for ultra-high efficiency power systems | 94 |
Citation counts favour older filings that have had more time to accumulate citations within the searched corpus; treat them as a signal of influence on subsequent drafting, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three patterns stand out once family counts, IPC composition and momentum are read together.
The growth phase has passed
Annual filings climbed from 33 in 2017 to a peak of 95 in 2022 and have fallen in the years since. That shape is more consistent with a maturing claim space than an emerging one — new entrants are more likely to be working around existing claims than staking fresh architectural ground.
Claim density sits in the stack-adjacent subclass
H01M carries the large majority of records, meaning the core fuel-cell-and-BOP interface is the most heavily claimed territory. Subclasses tied to turbine integration (F02C) and corrosion (C23F) sit well below 50 records each, which is a smaller drafting footprint relative to their operational importance in commercial-scale plant.
Recent-year activity has gone quiet across former leaders
Multiple assignees with strong historical filing counts show zero filings in the latest year and year-on-year declines of -100%. That does not necessarily mean withdrawal from the field — publication lag affects the newest filings most — but it does mean the visible activity is not currently led by any single dominant filer.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to molten carbonate fuel cell balance of plant, with the prior art for and against each one.
Who has filed, and where the gaps sit
Co-assignee pairings and recent-year momentum point to a field with established players but no filer currently building fresh volume.
Joint filings cluster around a small number of partnerships
The strongest co-assignee pairing in this corpus shares 53 families, well above the next pairings recorded. Ten co-assignee pairs exist in total, suggesting joint development work is concentrated rather than broadly distributed across the field.
No current filing leader is visible in the newest data
Several of the historically largest assignees register zero filings in the latest year, with year-on-year drops of -100%. Given the roughly 18-month publication lag, some of this is an artefact of timing rather than a true stop in R&D, but it means recent competitive positioning cannot be read directly from the newest-year counts.
US and European filing dominate, PCT signals global intent
The United States accounts for the largest single share of receiving-office filings, followed by the EPO. The sizeable WIPO/PCT count indicates that a meaningful share of applicants are pursuing multi-jurisdiction protection rather than filing only domestically.
| Assignee | Recent year | YoY |
|---|---|---|
| FuelCell Energy | 0 | -100% |
| Cummins Inc. | 0 | -100% |
| Honeywell International Inc. | 0 | — |
| FuelCell Energy, Inc. | 0 | -100% |
| Bloom Energy Corporation | 0 | — |
| Preston Products Company | 0 | — |
| DEVOE LAMBERT | 0 | — |
| DEVOE ALAN | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, whitespace filing, or competitive tracking.
Check freedom-to-operate against the highest-cited prior art
The most-cited records in this corpus, several dating to the 2000s, still anchor a large share of subsequent claim language around fuel cell hybrid systems and operating efficiency.
Explore citation map in EurekaDraft around the thinner IPC subclasses
F02C turbine integration and C23F corrosion management carry far fewer filings than H01M, which may leave room for narrowly targeted claims in those branches.
Run a whitespace search in EurekaTrack assignees through the publication-lag window
Zero recent-year filings across several historical leaders may reverse once 2025-2026 filings publish; a re-check in six to twelve months will clarify whether activity has genuinely slowed.
Set up assignee alerts in EurekaCommon questions about MCFC balance-of-plant patents
Balance of plant refers to everything around the electrochemical stack that makes a fuel cell system run as a power plant: fuel processing subsystems that condition the incoming fuel, thermal management subsystems that handle stack heat, gas handling, and control systems. This dataset specifically searches for MCFC filings that also reference balance-of-plant, fuel processing subsystem, or thermal management subsystem language, which is why it returns 747 families rather than the much larger set of all MCFC-related patents. It excludes filings focused purely on stack chemistry or membrane materials unless they also touch these subsystem terms.
The trend in this dataset does not support that. Filings rose from 33 in 2017 to a peak of 95 in 2022, then declined in subsequent years. Because publication lags filing by roughly 18 months, the very newest years are undercounted, but the overall shape — a rise to a mid-period peak followed by decline — points to a claim space that has already been substantially staked out rather than one still in an early growth phase.
H01M, the batteries, cells and fuel cells IPC subclass, dominates this dataset with 648 of 747 records. That is far ahead of the next largest subclasses, C09K materials (81) and C25B electrolytic production (42). Subclasses tied to turbine integration (F02C, 32 records) and corrosion management (C23F, 28 records) carry noticeably less coverage despite being operationally important to running an MCFC plant at scale.
The ranking in this dataset is dominated by a mix of established fuel-cell and industrial-gas companies along with individual inventors appearing in co-assignee pairs. Rather than one company holding a commanding lead, several of the historically active assignees show zero filings in the latest recorded year, which makes the current competitive picture less settled than the historical filing counts alone would suggest. Checking recent-year momentum alongside total family counts gives a fuller picture than ranking on volume alone.
The thinner IPC subclasses in this dataset — particularly F02C for turbine integration and C23F for corrosion and metal removal — carry a fraction of the filings seen in H01M, despite being technically relevant to commercial-scale plant operation. Fuel processing subsystem catalysis integration and thermal management subsystem controls also show comparatively light coverage relative to their operational importance. These are reasonable starting points for a novelty search, though any specific claim should be checked against the highest-cited prior art in the corpus before drafting.
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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.