Molten Carbonate Fuel Cell Stack Patents: Leaders & Trends 2026
- Filing has gone quiet. the field peaked at 6 families in 2018 and has since flattened, with the 2022 midpoint at zero new filings.
- One subclass dominates. H01M covers 53 of 56 records, meaning almost every filing sits inside core battery/fuel-cell claim territory rather than adjacent mechanical or materials classes.
- The most-cited prior art predates the search window. the top-cited records reach back to stack assembly and gas-manifold patents filed well before 2015, and still anchor freedom-to-operate analysis today.
A narrow, mature filing field
Molten carbonate fuel cell (MCFC) stack work is a small, tightly-scoped patent field: 56 published families since 2015 across stack architecture, cell stacking design and manifold engineering. The search string captures a specific mechanical and thermal problem — how gas is distributed and sealed across a stack — rather than the broader electrochemistry of carbonate fuel cells. Filing activity peaked in 2018 and has not returned to that level since, which for a mechanical sub-domain like this usually signals either a settled design consensus or reduced commercial investment rather than an emerging one.
Because publication typically lags filing by around 18 months, the most recent one to two years in any trend understate true activity. Even accounting for that lag, the flat 2022 midpoint suggests this is a domain of incremental refinement rather than active land-grab, and most of the highest-cited prior art was filed before the current search window opened.
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Filing trend and technology composition
The filing curve and IPC spread both point to a field defined early and refined since, with almost all activity concentrated in the core fuel-cell classification.
A single peak, then plateau
Filings rose to a peak of 6 in 2018, then declined toward a flat midpoint by 2022 and stayed there through the most recent, still-partial year. There is no second wave visible in this data.
H01M carries almost the entire field
53 of 56 records classify under H01M (batteries, cells and fuel cells). The remaining handful spread thinly across materials (C09K), ceramics and refractories (C04B), vehicle propulsion (B60K/B60L) and flow-control hardware (F15C, F16K) — evidence that manifold and sealing innovation here is claimed mostly as fuel-cell apparatus, not as separate mechanical or materials inventions.
Shares are the percentage of the 56 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 Fuel Cell Stack with Eureka
This page is one run against one query. Ask Eureka your own question about molten carbonate fuel cell fuel cell stack and every answer comes back with the patent numbers behind it.
Try EurekaThe prior art still shaping this field
Wet seal caulk with enhanced chemical resistance (US20190280312A1)
A caulk composition includes at least one powder component and at least one binder component, such that the powder component has a particle size distribution in the range of 95% less than 25 μm and 90% greater than 1 μm. A molten carbonate fuel cell (MCFC) includes a fuel cell stack, a manifold, and the caulk composition disposed in between the fuel cell stack and the manifold.Filed by FuelCell Energy, Inc., published 2019-09-12. Notable for claiming the seal material at the stack-manifold interface rather than the manifold geometry itself.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20040137300A1 | Piezoelectric axial flow microvalve | 105 |
| 2 | US20050112425A1 | Fuel cell for hydrogen production, electricity generation and co-production | 94 |
| 3 | WO1999057781A1 | Fuel cell stack assembly | 53 |
| 4 | US20050271910A1 | Fuel cell stack with even distributing gas manifolds | 33 |
| 5 | GB2336937A | Stack assembly primarily for an electrochemical cell | 25 |
| 6 | US20070178361A1 | Manufacture of electrical energy generation equipment | 22 |
| 7 | US7159841B2 | Piezoelectric axial flow microvalve | 18 |
| 8 | US7531264B2 | Fuel cell stack with even distributing gas manifolds | 10 |
| 9 | US20070231663A1 | Wet-seal caulk for carbonate fuel cell | 9 |
| 10 | EP1683216A2 | Fuel cell for hydrogen production, electricity generation and co-production | 9 |
Citation counts favour older filings simply because they have had longer to accumulate citations inside this searched corpus; treat them as a signal of influence on later drafting, not of present-day importance.
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 the trend, classification and citation data are read together.
The field has not reheated
Activity peaked at 6 families in 2018 and the 2022 midpoint sits at zero. A new entrant is not walking into a crowded, fast-moving space; it is walking into a settled one where the incumbents' claims were largely staked out years ago.
Almost everything is claimed as fuel-cell apparatus
The near-total concentration in H01M means manifold and sealing inventions are typically drafted as part of the fuel-cell stack claim, not as standalone mechanical patents. Drafters targeting flow-control or sealing hardware alone should still search H01M first.
The anchoring prior art predates 2015
The most-cited documents in this corpus, including the piezoelectric microvalve and early fuel cell stack assembly filings, were published before the search window opened. Any freedom-to-operate review needs to reach back past 2015 to those foundational assemblies and manifold-distribution patents.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to molten carbonate fuel cell fuel cell stack, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Ultra Cell Corporation | NEWELL KENNETH J | 2 |
| Ultra Cell Corporation | KAYE IAN W | 2 |
| Ultra Cell Corporation | BRANTLEY JENNIFER E | 2 |
| Ztek Corporation | HSU MICHAEL S | 2 |
| Jienengshi Corporation | Cummins Inc. | 2 |
| HYTEON | ELKAIM DAVID | 1 |
| HYTEON | CHOUINARD JEAN GUY | 1 |
| HYTEON | BAI DINGRONG | 1 |
Only 9 co-assignee pairs appear across the corpus, and the strongest pairings link a single corporate assignee to named individual inventors rather than to other companies — this is a field of solo corporate filers, not joint ventures.
Who holds the stack and manifold art
Recent-year momentum is flat across every assignee tracked in this corpus — none show filings in the latest year, consistent with the field-wide plateau. Positioning here is about historical claim depth, not current filing velocity.
No active filer in the most recent year
Every assignee tracked in the recent-momentum data, including FuelCell Energy, Ballard Power Systems and Ztek, shows zero filings in the latest tracked year. Read alongside the 18-month publication lag, this likely understates true activity, but it does not change the overall picture of a quiet field.
Collaboration is the exception
The nine identified co-assignee pairs are dominated by one corporate assignee paired repeatedly with named individual inventors, rather than by cross-company joint filings. There is little evidence here of joint-venture or licensing-driven co-development.
US and PCT dominate the filing strategy
The United States receives the largest share of filings, followed by WIPO/PCT routes and the EPO, with Canada, Austria and Australia trailing. This points to a primarily US-anchored competitive set that extends internationally through PCT rather than filing broadly at national offices from the outset.
| Assignee | Recent year | YoY |
|---|---|---|
| FuelCell Energy, Inc. | 0 | — |
| HYTEON | 0 | — |
| Ultra Cell Corporation | 0 | — |
| Ztek Corporation | 0 | — |
| MARVICK FUELCELLS LTD | 0 | — |
| Ballard Power Systems Inc. | 0 | — |
| British Gas plc | 0 | — |
| Jienengshi Corporation | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, drafting, or competitive tracking.
Run a freedom-to-operate check on pre-2015 art
The highest-cited records in this corpus were filed before the search window opened, so a proper clearance review needs to reach back to the original stack assembly and gas-manifold patents, not just the 2015-2026 set.
Explore prior art in EurekaTest draft claims against the thin IPC branches
Sealing chemistry, flow-control hardware and ceramic insulation each have only a few records outside H01M. Drafting a claim there and checking it against the full corpus shows quickly whether the space is really open.
Draft and check claims in EurekaTrack assignee filings past the data cut-off
Because publication lags filing by around 18 months, the flat recent-year momentum may already be shifting. Monitoring the named assignees going forward will catch new filings before they show up in a static search.
Set up monitoring in EurekaCommon questions on MCFC stack patents
This dataset identifies 56 published patent families between 2015 and mid-2026 that match stack architecture, cell stacking design or manifold design claims specific to molten carbonate fuel cells. That is a small, specialised field compared to fuel cell electrochemistry broadly. Filing peaked at 6 families in 2018 and has not returned to that level since, so the count grows slowly rather than in bursts.
FuelCell Energy, Ballard Power Systems and Ztek are among the assignees tracked in this corpus, alongside other named corporate and individual filers. None of the tracked assignees show filings in the most recent year, which is consistent with the field-wide plateau rather than any single company exiting. Ranking by family count is rendered separately in the data tables on this page; treat any single company's position as a snapshot, not a permanent lead.
The trend data shows a peak of 6 families in 2018 followed by a decline to a flat midpoint by 2022, with no second wave since. This pattern is typical of a mechanical sub-domain where the core stack, sealing and manifold designs were established early and later work is incremental rather than novel. It may also reflect reduced commercial investment in MCFC specifically, as competing fuel cell chemistries have drawn more recent R&D attention; the data here cannot distinguish between those explanations.
The patent, assigned to FuelCell Energy and published in 2019, claims a caulk composition defined by a specific powder particle-size distribution, used as a seal between an MCFC stack and its manifold. It blocks seal compositions falling inside that particle-size range and binder structure when applied at the stack-manifold interface. It does not claim manifold geometry or the stack architecture itself, so alternative seal chemistries or different particle-size distributions sit outside its literal scope, though a full design-around review should check the full claim set rather than the abstract alone.
The IPC composition shows 53 of 56 records under H01M, leaving only a handful of filings in adjacent classes such as ceramics and refractories, vehicle propulsion integration, and flow-control hardware like valves and fluidic elements. That thin coverage suggests claim space is more open around sealing chemistry variants, ceramic insulation approaches, and vehicle-mounted MCFC integration than around core stack assembly, which is already densely claimed. A search restricted to those adjacent classes before drafting is a low-cost way to confirm how open they really are.
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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.