Electric Double Layer Capacitor Patents: Leaders & Filing Trends 2026
Electric double layer capacitor patent landscape: who leads filing, how the top assignees concentrate, filing trend since 2017, IPC composition and the most-cited prior art.
Filing growth = 2021 (74 records) → 2024 (30); 2024 is the last year we treat as complete. Top-5 share = the 5 largest assignees ÷ all 6,684 records in scope (CR5), not the ranked leaders only.
What this landscape covers
This landscape maps 6,684 published records classified under H01G11 (electric double layer capacitors) with claims or title/abstract language matching EDLC and related supercapacitor terminology. The scope spans filings from 2015 through the 2026 data cut-off, drawing on assignee, IPC, citation and receiving-office data to show where claim density sits today. Publication lags filing by roughly 18 months, so the most recent one to two years in any trend understate real filing activity.
The dataset centres on electrode materials, carbonaceous active materials, electrolyte formulations and cell construction for electric double layer capacitors, with meaningful overlap into battery (H01M) and inorganic compound (C01B) classifications where hybrid or composite electrode work sits.
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Filing trend and technology composition
Two views of the same 6,684 records: how filing volume has moved year over year, and which IPC subclasses the claims actually sit in.
Filing trend: a 2018 peak followed by a sustained pullback
Filings rose to a peak of 124 in 2018, then declined; the clean comparison is 2021 (74) to 2024 (30), a -59% move over that three-year span. 2024 is the last year with a complete publication record — 2025 and 2026 figures will fill in as later-filed applications publish.
Publication lags filing by roughly 18 months, so 2025 onwards are still filling in. Growth rates on this page therefore end at 2024; running them to the last bar would understate the field.
Technology composition: capacitor core claims dominate, battery overlap is significant
H01G (capacitors) covers effectively the entire scope by construction. Beyond that, H01M (batteries, cells & fuel cells) appears in 21.1% of the 6,684 records, C01B (non-metallic elements & inorganic compounds) in 11.4%, and smaller shares extend into power/grid systems, conductors, nanotechnology, polymer compositions and heterocyclic compounds — each record can carry more than one class, so shares sum above 100%.
Shares are the percentage of the 6,684 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Electric Double Layer Capacitor Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about electric double layer capacitor patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited patents in this field
Electrode material and electrode for electric double layer capacitor (US7948738B2)
The filing describes an electrode material combining a carbonaceous material — derived by thermal treatment or activation of fullerene-containing soot or its extraction residue — with activated carbon, aimed at lowering internal resistance while raising capacitance in the finished electric double layer capacitor.Filed by Panasonic; granted 2011-05-24.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4862328A | Electric double layer capacitor | 208 |
| 2 | WO2002076924A1 | Ionic liquid, electrolyte salt for storage device, electrolytic solution for storage device, electric double … | 203 |
| 3 | US5150283A | Electric double layer capacitor and method for producing the same | 203 |
| 4 | JP1999317333A | Carbon material for electric double-layer capacitor and manufacture of the same, and electric double-layer ca… | 189 |
| 5 | JP2001089119A | Carbonaceous material, method for producing and electric double layer capacitor using the carbonaceous materi… | 161 |
| 6 | US5953204A | Electric double layer capacitor | 153 |
| 7 | US6847517B2 | Polarizable electrode for electric double layer capacitor and methods for producing polarizable electrode and… | 148 |
| 8 | JP1997055342A | Electric double layer capacitor | 148 |
| 9 | JP2008060060A | Coating liquid for manufacturing electrode plate, undercoating agent, and use thereof | 147 |
| 10 | US20030180622A1 | Separator for electrochemical device and method for producing the same, and electrochemical device | 146 |
Citation counts favour older records simply because they have had more time to accumulate citations inside this corpus — read them as a signal of influence on subsequent filings, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Four readings of the same dataset, aimed at where to file, who to watch, and what is still open.
The top of the field is dense, but not locked up
The five leading assignees hold 23.8% of all 6,684 records in scope, rising to 34.9% for the top ten. That leaves roughly two-thirds of filing activity spread across a long tail of smaller entrants, which is where most freedom-to-operate analysis in this field actually happens.
Volume has pulled back sharply from its 2018 peak
After peaking at 124 filings in 2018, annual volume fell from 74 in 2021 to 30 in 2024 — the last year with a complete publication record. That decline says less about whether the technology is still active and more about where R&D investment has shifted within energy storage.
Battery overlap is the largest adjacent claim territory
Beyond the core H01G capacitor classification, 21.1% of the 6,684 records also carry a H01M (battery/cell) classification, and 11.4% carry C01B (inorganic compounds) — evidence that hybrid electrode and composite-material work is a substantial, not marginal, part of this field.
Japan is the centre of gravity for EDLC filing
Japan receives 3,481 of the filings tracked here, more than four times the next office, the United States at 838, followed by South Korea, Europe and China. Any competitive-intelligence read of this field has to start with Japanese-language prosecution and prior art.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to electric double layer capacitor patent landscape, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| AGC Inc. (Asahi Glass Co., Ltd.) | Elna Co., Ltd. | 163 |
| Isuzu Motors Ltd. | Fuji Electrochemical Co., Ltd. | 28 |
| Honda Motor Co., Ltd. | Kuraray Chemical Co., Ltd. | 28 |
| Panasonic Corporation (Japan) | Sanyo Chemical Industries, Ltd. | 25 |
| Honda Motor Co., Ltd. | Daido Metal Co., Ltd. | 21 |
| Nisshinbo Co., Ltd. | Nisshinbo Holdings Inc. | 16 |
| Tokin Corporation | NEC Tokin Hyogo | 15 |
| Tokin Corporation | NEC Tokin Ceramics | 15 |
Co-assignee pairings are rare in this dataset — only 10 pairs recorded — but the strongest pairing appears 163 times, suggesting a small number of long-running joint-development programmes rather than broad industry co-filing.
Where to take this analysis
The dataset points to specific follow-up work depending on whether the goal is freedom-to-operate, competitive tracking, or identifying open claim space.
Map the long tail below the top 10
With 34.9% of records held by the top 10 assignees, the remaining majority sits with smaller filers. Screening that tail for recent activity is often where emerging competitive threats and licensing targets actually surface.
Explore assignee detail in EurekaTrack the H01M/C01B overlap directly
Hybrid electrode and inorganic-composite claims sit across two IPC classes rather than one. Building a query that follows both, rather than H01G alone, avoids missing where the newer materials work is being filed.
Build a cross-class search in EurekaWatch Japan-origin filings for signal on next moves
With 3,481 of the tracked filings received in Japan against 838 in the US, prosecution and continuation activity there tends to lead. A dedicated Japan-first monitoring feed catches shifts earlier than a global-only view.
Set up office-level monitoring in EurekaCommon questions on the EDLC patent landscape
The assignee ranking behind this dataset covers 100 companies, with the leader holding 580 records and the field concentrating meaningfully at the top: the top 5 hold 23.8% of all 6,684 records in scope, and the top 10 hold 34.9%. That still leaves the majority of filings distributed across a long tail of smaller entrants, so a single-company view understates how fragmented the rest of the field is. Practically, freedom-to-operate work needs to look well past the leaders.
Filing volume peaked in 2018 at 124 and has since declined, with the clean measured span showing a -59% drop from 74 filings in 2021 to 30 in 2024. 2024 is the most recent year with a complete publication record, since publication lags filing by roughly 18 months, so 2025 and 2026 figures are still filling in and should not yet be read as continuing the decline. The honest reading is a sustained pullback from a mid-decade peak, not a technology in early growth.
Beyond the core H01G capacitor classification, the largest overlap is with H01M — batteries, cells and fuel cells — appearing in 21.1% of the 6,684 records, reflecting hybrid electrode and combined energy-storage device work. C01B, covering non-metallic elements and inorganic compounds, appears in 11.4% of records, largely tied to carbon and activated-carbon electrode materials. Smaller overlaps extend into power/grid systems, conductors, nanotechnology and polymer compositions, each in the low single digits of records.
Japan is by far the dominant receiving office at 3,481 filings, more than four times the next-largest office, the United States at 838. South Korea (705), Europe via the EPO (626), China (325) and the WIPO PCT route (253) follow behind. This distribution reflects where the historical carbon-material and electrode-manufacturing base for EDLCs has concentrated, and it means Japanese-language prior art searching is essential for any serious clearance work in this field.
US7948738B2, assigned to Panasonic, claims an electrode material combining a carbonaceous material derived from fullerene-containing soot with activated carbon, aimed at reducing internal resistance while increasing capacitance. It is a representative example of the carbon-material electrode work that dominates citation activity in this field, sitting alongside other highly cited records like US4862328A and US5150283A. Anyone designing a new carbon-composite electrode should check this family specifically rather than assuming general activated-carbon prior art clears it.
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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.