Flywheel & Gravity Storage Patents: Who Leads, Where the Gaps Are 2026
- No single filer dominates. the leading assignee holds 61 records out of 1,845, and the top 5 combined account for just 12.1% of all records in scope.
- Filing has plateaued, not declined. the field held flat at 90 filings in both 2021 and 2024 — a 0% three-year change — after peaking at 116 in 2022.
- Motors and generators dominate the claim space. H02K appears on 33.6% of records, more than any other IPC subclass, ahead of spring/damper mechanisms (F16F) and grid power systems (H02J).
Filing growth compares 2021 (90 records) with 2024 (90) — 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 1,845 records in scope (CR5), not by the ranked leaders only.
What the flywheel and gravity storage patent record shows
Flywheel and gravity-based mechanical storage sit at the intersection of rotating machinery, grid power electronics and vehicle propulsion. The 1,845 records captured here span 2015 through the 2026 cut-off, combining traditional flywheel energy storage — rotor, bearing and containment engineering — with the newer gravity-storage variants that borrow much of the same power-conversion and charge-control claim language. Because the search string ties flywheel and gravity storage terms to energy-conversion and charge-control language, the corpus leans toward systems claims rather than pure materials or manufacturing patents.
Filing offices split unevenly: China leads with 534 records, ahead of the United States at 387, EPO at 193, Japan at 156, WIPO/PCT at 153 and the United Kingdom at 79. That distribution points to a field where Chinese filers have scaled activity meaningfully, while US and European filings remain concentrated among a smaller set of established industrial names.
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Filing trends and technology composition
Two views matter here: how filing volume has moved year over year, and how claims distribute across IPC subclasses. Both are read against the same 1,845-record base, so shares are comparable across sections.
Filing trend, 2017–2026
Annual filings rose from 44 in 2017 to a peak of 116 in 2022, then settled back to 90 in both 2021 and 2024 — a 0% change across that three-year span. The 2025 and 2026 figures (down to 12 in the partial 2026 year) understate real activity, since publication typically lags filing by around 18 months; they should not be read as a decline.
IPC subclass composition
H02K (electric motors & generators) appears on 33.6% of the 1,845 records, the single most common classification, followed by F16F (springs & vibration dampers) at 20.7% and H02J (power supply & grid systems) at 17.2%. Vehicle propulsion (B60K), bearings (F16C), spring/weight motors (F03G), motor control (H02P) and hydraulic machines (F03B) each sit between 5.5% and 7.9%. Because records can carry multiple IPC codes, these shares sum to well over 100% and should be read individually, not stacked.
Shares are the percentage of the 1,845 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Flywheel & Gravity Storage Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about flywheel & gravity storage patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited prior art
US7119520B2 — Energy storage flywheel test control system (Honeywell International, 2006)
A system and method for removing energy from the rotating group in an energy storage flywheel system during flywheel system testing includes one or more sensors operable to sense operational parameters of the energy storage flywheel and to supply sensor signals representative thereof. A primary control circuit is coupled to receive the sensor signals and, in response thereto, selectively supplies a primary brake activation signal to a brake. The brake, in response to the brake activation signal, selectively supplies a brake force to the energy storage flywheel.Filed by Honeywell International — illustrates how test and brake-control circuitry around a flywheel rotor gets claimed independently of the storage mechanism itself.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6056716A | Hypodermic fluid dispenser | 338 |
| 2 | US6367570B1 | Hybrid electric vehicle with electric motor providing strategic power assist to load balance internal combust… | 287 |
| 3 | US20060250902A1 | Plug-in hybrid vehicle with fast energy storage | 252 |
| 4 | US4228360A | Wave motion apparatus | 216 |
| 5 | US8723344B1 | Energy harvesting system | 185 |
| 6 | US4740001A | Sprag wheel | 141 |
| 7 | GB2031822A | A method and apparatus for driving a load, such as a vehicle | 138 |
| 8 | US6897587B1 | Energy storage flywheel with minimum power magnetic bearings and motor/generator | 121 |
| 9 | US6097127A | Permanent magnet direct current (PMDC) machine with integral reconfigurable winding control | 107 |
| 10 | US5998899A | Magnetic bearing system including a control system for a flywheel and method for operating same | 106 |
Citation counts reward older filings simply because they have had longer to accumulate citations; treat this table as a map of influential prior art, not of current commercial 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 in this dataset are worth acting on rather than just noting.
No single company controls the field
The leading assignee holds 61 records, and the five largest filers together account for only 12.1% of all 1,845 records in scope. That is a genuinely fragmented landscape rather than one dominated by a handful of blocking portfolios — new entrants are competing against a long tail of single- and few-filing organisations, not a wall of concentrated prior art.
Filing has plateaued after a 2022 peak
Volume climbed from 44 filings in 2017 to 116 in 2022, then eased back to 90 by 2024 — flat against 2021's 90. Read the 2025–2026 dip as a publication-lag artefact, not a retreat from the technology; most of that activity has not finished publishing yet.
Rotating-machine claims outweigh storage-mechanism claims
H02K (electric motors & generators) sits on over a third of records, well ahead of spring/damper mechanisms and grid-power classes. That suggests much of the competitive claiming activity is happening around the motor-generator interface rather than the storage medium itself — a signal for where freedom-to-operate searches should start.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to flywheel & gravity storage patent landscape, with the prior art for and against each one.
Who is filing, and where the gaps sit
The ranked leaders span industrial conglomerates, defence-adjacent names and a growing cohort of Chinese energy-storage specialists. None of them individually controls enough of the field to set the terms of entry.
A fragmented top of the table
The single largest filer holds 61 of 1,845 records; by tenth place that figure has fallen to 20. The drop-off from first to tenth place is steep, which means influence in this field is not held by one or two companies but distributed across a wider set of industrial and specialist filers.
Recent activity has cooled across the named leaders
Recent-year momentum data shows several previously active assignees recording zero filings in the latest year, including names with strong historical volume. This is consistent with the broader plateau in the trend data rather than a sign that any one company has withdrawn from the technology.
Joint filing is limited and mostly domestic
Only 10 co-assignee pairs appear in the dataset, with the strongest pairing linking a Chinese energy-technology developer to a bridge-and-road engineering group at 6 shared records. Co-filing here looks more like project-specific engineering partnerships than cross-industry technology alliances.
| Assignee | Recent year | YoY |
|---|---|---|
| Huachi Kinetic Energy (Beijing) Technology Co., Ltd. | 2 | 0% |
| Raytheon Company | 0 | -100% |
| ACTIVE POWER INC | 0 | — |
| Honeywell International Inc. | 0 | — |
| Ricardo UK Ltd. | 0 | — |
| Heptron International Limited | 0 | — |
| LEVISTOR LTD | 0 | — |
| Beijing Honghui International Energy Technology Development Co., Ltd. | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, licensing, or new filing strategy.
Run a freedom-to-operate check on the H02K/F16F overlap
With over half of records touching motor-generator or spring/damper claims, any new flywheel design should be screened against both classes together rather than either alone.
Explore claim overlaps in Eureka →Track the momentum shift among cooling leaders
Several established filers show zero recent-year activity — worth confirming whether that reflects a strategic pause, portfolio maturity, or publication lag before assuming market exit.
Monitor assignee activity in Eureka →Scope claims in the identified white-space branches
Hybrid flywheel-battery control and modular gravity-mass hoist units carry comparatively light claim density relative to the rest of the field — a starting point for new filings.
Draft claims around white space in Eureka →Common questions about flywheel and gravity storage patents
The assignee ranking is fragmented rather than dominated by one company: the leading filer holds 61 of the 1,845 records in scope, and the top five combined account for only 12.1% of all records. The named leaders include long-standing industrial and aerospace-adjacent names alongside a growing group of Chinese energy-storage specialists. Because the field is this spread out, competitive positioning depends more on specific claim overlap than on avoiding a single dominant portfolio.
Filing volume rose from 44 records in 2017 to a peak of 116 in 2022, then eased to 90 in 2024 — flat against the 90 filed in 2021, a 0% three-year change. The apparent drop in 2025 and 2026 reflects publication lag, since patent publication typically trails filing by around 18 months, rather than a genuine decline in R&D activity. The most defensible read is a plateau after a 2022 peak, not a downturn.
H02K (electric motors and generators) is the most common classification, appearing on 33.6% of the 1,845 records, followed by F16F (springs and vibration dampers) at 20.7% and H02J (power supply and grid systems) at 17.2%. Vehicle propulsion, bearings, spring/weight motor mechanisms, motor control and hydraulic machines each appear on between roughly 5.5% and 7.9% of records. Since many filings carry multiple IPC codes, a single patent often spans several of these classes at once.
The dense claim territory sits around motor-generator design, spring/damper mechanisms and grid power integration, all carrying well over 15% of records each. Adjacent branches such as hybrid flywheel-battery charge blending, modular gravity-mass hoist units and magnetic bearing wear-monitoring carry comparatively little claim density relative to the core. A first claim in one of these areas is more likely to clear prior art cleanly than a claim written directly against the H02K or F16F core.
US7119520B2, assigned to Honeywell International, claims a test-control system that uses sensors and a primary control circuit to selectively apply brake force to a flywheel rotor during system testing. It is narrowly scoped to test and brake-activation circuitry rather than to the flywheel storage mechanism itself, so it does not broadly block flywheel energy-storage designs generally. Anyone building test rigs or brake-control loops around a flywheel rotor should still review its specific claim language before finalising a control architecture.
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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.