Water Electrolysis Patents: Top Companies & Filing Trends 2026
- 5.6% concentration. The five leading assignees hold only 1,675 of 30,056 records in scope — a shallow top rather than a dominant one.
- +30% growth, 2021-2024. Filings rose from 1,769 to 2,294 across the last complete three-year span, with 2022 the peak year so far at 2,369.
- C25B carries 42.1% of records. Electrolytic production of compounds is the dominant IPC subclass, well ahead of batteries and fuel cells at 16.8%.
Filing growth compares 2021 (1,769 records) with 2024 (2,294) — 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 30,056 records in scope (CR5), not by the ranked leaders only.
What the water electrolysis patent record actually shows
Water electrolysis patenting spans electrode catalysts, membrane chemistry, cell-voltage management and the downstream hydrogen production systems that consume the gas. The 30,056 records in scope are drawn from filings that name electrolyzer membranes, hydrogen evolution, electrode catalysts and electrochemical cells alongside the core water electrolysis and electrolytic hydrogen terms — so the corpus captures both the core electrochemistry and its adjacent process engineering. No single assignee controls the field: the leader holds 422 records against a ranked field of 100 companies, and the top five combined reach only 5.6% of all records in scope.
That shallow concentration matters for strategy. A field where the top ten hold under 10% of filings is not yet locked down by a handful of incumbents, which means freedom-to-operate work has to look past the obvious leaders to a long tail of single- and few-filing entrants. Publication lags filing by roughly 18 months, so the most recent year of data understates real filing activity and should be read as a floor, not a ceiling.
Filing trend and technology composition
Two views of the same 30,056-record corpus: how filing volume has moved year over year, and which IPC subclasses carry the claim density.
Filing trend, 2017-2026
Filings climbed from 713 in 2017 to a peak of 2,369 in 2022, then held above 2,000 through the last complete year. The 2021-to-2024 span shows +30% growth (1,769 to 2,294); 2025 and 2026 figures are still filling in under normal publication lag and should not be read as a slowdown.
Technology composition by IPC subclass
C25B (electrolytic production of compounds) covers 42.1% of the 30,056 records in scope, more than twice the share of H01M (batteries, cells and fuel cells) at 16.8%. Catalysis (B01J), separation processes (B01D) and water treatment (C02F) each sit in single digits, marking them as adjacent rather than core claim territory. Records can carry multiple classes, so these shares sum to more than 100%.
Shares are the percentage of the 30,056 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Water Electrolysis Patent Landscape with Eureka
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Try EurekaA representative filing and the most-cited prior art
Electrode catalyst for water electrolysis cell, water electrolysis cell and water electrolyzer (US20230220571A1)
An electrode catalyst for a water electrolysis cell includes a catalyst and a polymer of intrinsic microporosity with a Tröger's base skeleton containing a quaternary ammonium group. A water electrolysis cell built from it includes an anode, a cathode and an electrolyte membrane positioned between them, with at least one electrode carrying the catalyst.Filed by Panasonic Intellectual Property Management, published 2023-07-13.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20080296155A1 | Low oxygen in vivo analyte sensor | 941 |
| 2 | US20080208025A1 | Low oxygen in vivo analyte sensor | 935 |
| 3 | US20160045841A1 | New and improved system for processing various chemicals and materials | 860 |
| 4 | US20050056552A1 | Increasing bias for oxygen production in an electrode system | 809 |
| 5 | US20060195029A1 | Low oxygen in vivo analyte sensor | 777 |
| 6 | US7899511B2 | Low oxygen in vivo analyte sensor | 739 |
| 7 | US6509180B1 | Process for producing ethanol | 639 |
| 8 | US7771352B2 | Low oxygen in vivo analyte sensor | 620 |
| 9 | US5972196A | Electrochemical production of ozone and hydrogen peroxide | 588 |
| 10 | US20070282495A1 | System and method for assessing vehicle to grid (V2G) integration | 531 |
Citation counts favour older filings simply by virtue of being in the corpus longer; treat them as a measure of influence within this search, not of current technical importance.
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Three patterns stand out once the ranking, the trend and the IPC breakdown are read together.
The leaderboard is shallow, not dominant
With a leader at 422 records and a ranked field of 100 companies, no single assignee has cornered water electrolysis. Freedom-to-operate analysis has to widen past the obvious names to the long tail of single-digit filers.
Filing momentum is still building, not fading
The last complete three-year window shows real growth, not a plateau. 2022 was the peak year so far at 2,369 filings; the apparent dip after that reflects publication lag rather than declining interest.
Electrolytic production claims dominate the class map
C25B outweighs every other subclass by a wide margin, with H01M a distant second at 16.8%. Catalysis, separation and water treatment classes each sit under 8%, suggesting claim space there is thinner and more open.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to water electrolysis patent landscape, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| De Nora Permelec Ltd. | Yokohama National University | 143 |
| Toshiba Corporation | Toshiba Energy Systems & Solutions Corporation | 120 |
| De Nora Permelec Ltd. | Kawasaki Heavy Industries, Ltd. | 52 |
| De Nora Permelec Ltd. | Kyoto University | 25 |
| De Nora Permelec Ltd. | National Institute of Technology (KOSEN) | 15 |
| De Nora Permelec Ltd. | AquaEx Inc. | 11 |
| The Regents of the University of California | Opus 12, Inc. | 11 |
| De Nora Permelec Ltd. | thyssenkrupp Uhde Chlorine Engineers GmbH | 6 |
The corpus records ten identifiable co-assignee pairs, with the strongest joint-filing relationship reaching 143 shared records — evidence that some of the leading filers develop electrolysis IP through named research partnerships rather than solely in-house.
Who is filing, and where the activity is thinning
Recent-year momentum among the assignees with visible activity points downward across the board, which is expected given publication lag but still worth reading carefully before drawing conclusions about any single company's pipeline.
The top filer leads a shallow field
The leading assignee holds 422 records against a fifth-place figure of 300 and a tenth-place figure of 197 — a gentle slope rather than a cliff, which is consistent with the 5.6% top-five concentration figure.
Latest-year counts are down across named filers
Every assignee with visible recent-year activity shows a year-over-year decline, from -75% to -100%. This tracks the ~18-month publication lag rather than a genuine pullback from the technology.
Some leaders file jointly with university partners
The strongest identified co-assignee relationship in the dataset links an industrial electrode specialist with a national university, pointing to sustained joint R&D rather than one-off collaboration.
| Assignee | Recent year | YoY |
|---|---|---|
| Toshiba Corporation | 5 | -86% |
| Honda Motor Co., Ltd. | 2 | -83% |
| Asahi Kasei Corporation | 1 | -75% |
| The Regents of the University of California | 1 | -89% |
| UOP LLC | 1 | -92% |
| De Nora Permelec Ltd. | 0 | -100% |
| Proton Energy Systems, Inc. | 0 | — |
| Panasonic Intellectual Property Management Co., Ltd. | 0 | -100% |
Where to take this analysis
The dataset points to specific follow-up work rather than a single conclusion.
Map claim scope inside C25B
At 42.1% of records, C25B is too broad a bucket to treat as one claim territory. Breaking it into sub-groups would show whether electrode catalyst claims, cell architecture claims and process-control claims are equally dense.
Explore C25B sub-classes in EurekaTrack the co-filing partnerships
The strongest co-assignee pairs suggest that some of the leading filers rely on named research partners for core IP. Watching those pairs' joint output over time is a cheaper early-warning signal than watching either company alone.
Trace co-assignee networks in EurekaRe-check 2025-2026 once publications catch up
Every recent-year momentum figure in this dataset is a moving target because of publication lag. Re-running the trend and momentum views in 12-18 months will separate genuine slowdown from a reporting artefact.
Set a refresh alert in EurekaCommon questions about water electrolysis patents
No single company dominates the field: the leading assignee holds 422 records out of 30,056 in scope, and the top five combined reach only 5.6% of all records. The ranking includes 100 companies with a gradual slope from the leader down through tenth place at 197 records, rather than a sharp drop-off. This shallow concentration means competitive monitoring needs to cover a long tail of filers, not just the handful of best-known names.
Yes, over the last period that can be treated as complete: filings grew from 1,769 in 2021 to 2,294 in 2024, a 30% increase. The peak year so far is 2022 at 2,369 filings. Figures for 2025 and 2026 look lower, but that reflects the roughly 18-month lag between filing and publication rather than a real decline in activity.
The dominant IPC subclass is C25B, electrolytic production of compounds, covering 42.1% of the 30,056 records in scope. H01M (batteries, cells and fuel cells) follows at 16.8%, with catalysis (B01J), separation processes (B01D), and water treatment (C02F) each in single digits. Because a single patent can carry several IPC classes, these shares add up to more than 100% and should be read as overlapping coverage, not a strict breakdown.
The IPC data shows thinner filing density in areas adjacent to the core C25B territory, such as non-noble-metal hydrogen evolution catalysts, anion-exchange membrane durability, and bipolar plate corrosion coatings. High density in C25B means claim space there is heavily occupied, not necessarily that the underlying technology is fully mature, so a narrower claim within a crowded subclass can still be viable. Any freedom-to-operate assessment should still be run against the full ranked assignee list, since a shallow top-five share means relevant prior art can sit with lesser-known filers.
Citation counts in this corpus skew toward older filings simply because they have had more time to be cited by later applications. The most-cited records here date back roughly a decade or more, so a high citation count signals historical influence within this search rather than current commercial importance. For assessing what matters today, filing recency and IPC positioning are more useful signals than raw citation counts.
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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.