Molten Carbonate Fuel Cell Control Patents: Leaders & Trends 2026
- Filing peaked in 2022 at 82 records and has not returned to that level since, suggesting the core control approaches are largely staked out rather than still opening up.
- H01M dominates the IPC mix at 775 records but E21B (drilling), C09K and C01B each carry over 200 records, showing MCFC control art overlaps heavily with subsurface and materials filings.
- United States leads receiving offices with 548 filings more than four times the next-closest single-country office outside the EPO and PCT routes.
Filing growth compares 2021 (38 records) with 2024 (24) — 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 1,362 records in scope (CR5), not by the ranked leaders only.
What the molten carbonate fuel cell control patent set actually contains
Molten carbonate fuel cell (MCFC) control patents cover the mechanisms that keep a high-temperature electrolyte stack running safely and efficiently: temperature control loops, fuel utilization control, and broader system control strategy claims that coordinate gas feed, thermal management and electrolyte stability. The search set spans 2015 through mid-2026 and returns 1,362 published families, filed mostly through the United States, European and PCT routes.
The IPC composition is the first signal worth reading closely. H01M (batteries, cells and fuel cells) accounts for the largest share at 775 records, but E21B (earth and rock drilling), C09K (materials for miscellaneous applications) and C01B (non-metallic elements and inorganic compounds) each contribute over 200 records. That overlap points to a corpus where fuel cell control claims sit alongside adjacent process and materials art, rather than a narrowly siloed field.
Filing trend and technology composition
Two views of the same 1,362-family dataset: how filing activity has moved year over year, and which IPC subclasses carry the underlying technical content.
A peak in 2022, then a pullback
Annual filings rose from 34 in 2017 to a peak of 82 in 2022, then declined. With 2022 as the midpoint of the visible trend, the pattern reads flat-to-declining rather than accelerating. The most recent one or two years will understate true filing activity because publication typically lags filing by around 18 months, but the pullback from the 2022 peak predates that lag window and looks like a genuine slowdown in new filing.
Eight IPC subclasses, one dominant
H01M carries more than half of the visible weight at 775 records. E21B, C09K and C01B each sit above 200, with B01J, B01D, C25B and C10G trailing behind. The presence of drilling and hydrocarbon-processing subclasses alongside the core fuel cell class suggests some MCFC control claims are drafted defensively around thermal and gas-handling processes shared with other high-temperature industrial systems.
Shares are the percentage of the 1,362 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 Control System with Eureka
This page is one run against one query. Ask Eureka your own question about molten carbonate fuel cell control system and every answer comes back with the patent numbers behind it.
Try EurekaA foundational control patent and the most-cited prior art
US4810595A — Molten carbonate fuel cell, and its operation control method
The patent addresses a specific degradation mode: MCFC output falls over time as the molten carbonate electrolyte migrates and disturbs the electrode boundary equilibrium. The fix claimed is procedural rather than structural — shutting off or reducing the feed of reaction gases for a period to allow the cell to recover output.Filed by New Energy Development Organization (NEDO), Japan, 1989-03-07.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6688387B1 | In situ thermal processing of a hydrocarbon containing formation to produce a hydrocarbon condensate | 423 |
| 2 | US7011154B2 | In situ recovery from a kerogen and liquid hydrocarbon containing formation | 383 |
| 3 | US6782947B2 | In situ thermal processing of a relatively impermeable formation to increase permeability of the formation | 364 |
| 4 | US7077199B2 | In situ thermal processing of an oil reservoir formation | 356 |
| 5 | US6712136B2 | In situ thermal processing of a hydrocarbon containing formation using a selected production well spacing | 352 |
| 6 | US6880633B2 | In situ thermal processing of an oil shale formation to produce a desired product | 348 |
| 7 | US6969123B2 | Upgrading and mining of coal | 340 |
| 8 | US7066254B2 | In situ thermal processing of a tar sands formation | 337 |
| 9 | US6581684B2 | In Situ thermal processing of a hydrocarbon containing formation to produce sulfur containing formation fluids | 337 |
| 10 | US7096942B1 | In situ thermal processing of a relatively permeable formation while controlling pressure | 322 |
Citation counts inside a searched corpus favour older filings; treat this table as a signal of influence on later drafting, not of current commercial relevance.
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Read together, the trend line, the IPC spread and the citation table point to a field where the core control loop was staked out early and later filers have worked the margins.
Growth has stalled since the 2022 peak
Filings rose from 34 in 2017 to 82 in 2022 and have not matched that level since. For a technology this mature in its control approach, a plateau after a peak usually means the obvious control-loop configurations are already claimed.
Fuel cell claims sit inside a wider industrial overlap
H01M holds the majority share but E21B, C09K and C01B together account for a substantial minority. Drafting a control claim here without checking drilling and materials-processing art in those adjacent subclasses risks missing close prior art.
US is the dominant filing venue by a wide margin
United States receiving-office filings outnumber the EPO route by nearly three to one, and PCT filings sit below both. Enforcement and freedom-to-operate work should prioritise US prosecution history before any other jurisdiction.
Most-cited records predate the current control-focused wave
The highest citation counts in this corpus attach to older in-situ thermal processing patents rather than to recent control-strategy filings, a reminder that citation volume inside a searched set rewards age over present-day relevance.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to molten carbonate fuel cell control system, with the prior art for and against each one.
Who is active, and where momentum has gone quiet
Recent-year momentum across the tracked assignees is close to flat: most show zero filings in the latest year, and the one exception shows no year-over-year growth either.
General Electric is the only assignee still filing
Among the tracked assignees, General Electric shows one filing in the latest tracked year with 0% year-over-year change. Every other tracked assignee, including Shell entities, LG Fuel Cell Systems, Honeywell and Doosan, shows zero filings in the latest year.
Shell's internal co-assignee link is the strongest pairing
Shell International Research and Shell Canada share 13 families, the strongest co-assignee pair in the dataset. Two Honeywell-inventor pairings each carry 8 shared families, suggesting concentrated internal collaboration rather than cross-company joint filing.
Filing strategy is US-first with EPO as secondary cover
The gap between US filings and every other receiving office is large enough that assignees appear to be treating the US as the primary market for MCFC control claims, with EPO, PCT, Australia, Canada and Japan used for supplementary coverage.
| Assignee | Recent year | YoY |
|---|---|---|
| General Electric | 1 | 0% |
| Shell Petroleum | 0 | — |
| Shell International Research | 0 | — |
| LG Fuel Cell Systems | 0 | — |
| Honeywell International | 0 | — |
| Doosan | 0 | — |
| FuelCell Energy | 0 | — |
| Shell Canada | 0 | — |
Where to take this analysis
The dataset points to a plateaued filing trend with concentrated ownership at the top and thin coverage in a handful of adjacent control mechanisms.
Map the electrolyte migration claim space
US4810595A's gas-shutoff approach to output recovery is procedural; a structural or sensor-driven approach to the same degradation mode may sit outside its claims.
Explore in EurekaCheck freedom-to-operate against the Shell and Honeywell clusters
The strongest co-assignee pairs concentrate around Shell's internal entities and Honeywell inventor teams; any new US filing should be checked against both clusters specifically.
Run a clearance searchWatch for a filing rebound in the lag window
Publication lag of roughly 18 months means 2025-2026 filings are undercounted; revisit the trend line once that window clears before concluding the plateau is permanent.
Track filing trendsCommon questions about molten carbonate fuel cell control patents
In this dataset, it means a patent whose title, abstract or claims combine molten carbonate fuel cell (MCFC) subject matter with temperature control, fuel utilization control, or a broader system control strategy. That includes claims on thermal management loops, gas feed regulation, and electrolyte stability procedures like the gas-shutoff recovery method in US4810595A. It excludes MCFC patents that are purely about electrode materials or stack construction with no control claim.
Filings rose from 34 in 2017 to a peak of 82 in 2022 and have declined since, which typically signals that the most obvious control-loop configurations have already been claimed by early movers. It can also reflect commercial focus shifting toward other fuel cell chemistries such as solid oxide or PEM systems. Note that the most recent one to two years will always look understated because publication lags filing by roughly 18 months, so the true 2025-2026 count is not yet final.
Recent-year momentum data shows General Electric as the only tracked assignee with a filing in the latest year, and even that shows 0% year-over-year growth. Shell entities, LG Fuel Cell Systems, Honeywell and Doosan all show zero filings in the latest tracked year. This does not mean these companies have exited the space entirely, since publication lag can hide filings not yet public, but it does mean visible new activity from the historically largest filers has gone quiet.
The clearest gaps sit in dynamic fuel utilization setpoint adjustment, multi-stack thermal load balancing, and control schemes that integrate co-located CO2 separation with the fuel cell's own control loop. These sub-areas show up in the adjacent IPC classes such as C25B and B01D without corresponding depth of dedicated control claims. A first claim in one of these areas would likely combine a sensor input specific to the sub-area with a control action tied to the MCFC's own operating parameters, rather than reusing the general shutoff-and-recover pattern from earlier art.
US4810595A claims a specific recovery method: reducing or shutting off reaction gas feed for a period to restore output lost to electrolyte migration. It does not block control approaches that address electrolyte migration through different means, such as continuous sensor-driven compensation rather than periodic shutoff, or that target different degradation mechanisms entirely. Anyone filing near this space should read its claims narrowly against the specific gas-shutoff mechanism rather than assuming it covers all output-recovery control strategies.
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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.