Electric Double-Layer Capacitor Hybrid Capacitor Patent Landscape
Electric Double-Layer Capacitor Hybrid Capacitor Patent Landscape in 2026
The electric double-layer capacitor hybrid capacitor space is a mature, Japan-dominated field in measured decline, with Panasonic Holdings leading a concentrated group of established incumbents. Filing activity has eased from its earlier peak, and the competitive structure favors incremental improvement over disruptive entry.
Panasonic Leads a Concentrated, Japan-Anchored Field
Panasonic Holdings Corp holds the top position in applicant rankings, followed closely by Mitsubishi Electric Corp and Mitsubishi Chemical Corp, each with 9 patent records. The top five filers collectively account for 40% of the combined total across the hundred largest filers, signaling a moderately concentrated competitive structure.
The top tier is composed almost exclusively of large Japanese industrial and chemical conglomerates. There is a visible but narrow gap between the leader and the second-tier cluster, with several players — ESPEC Corp, AGC Inc, and others — grouped tightly below.
| # | Applicant | Patent records | Share |
|---|---|---|---|
| 1 | Panasonic Holdings Corp | 15 | |
| 2 | Mitsubishi Electric Corp | 9 | |
| 3 | Mitsubishi Chemical Corp | 9 | |
| 4 | ESPEC Corp | 8 | |
| 5 | AGC Inc | 7 | |
| 6 | Semiconductor Energy Laboratory Co., Ltd. | 5 | |
| 7 | The Yokohama Rubber Co., Ltd. | 5 | |
| 8 | Nippon Chemi-Con Corp | 5 | |
| 9 | Sumitomo Electric Industries Ltd | 5 | |
| 10 | UACJ Corp | 4 |
| # | Applicant | Patent records | Share |
|---|---|---|---|
| 11 | National Institute for Materials Science | 3 | |
| 12 | Dalian Institute of Chemical Physics, Chinese Academy of Sciences | 2 | |
| 13 | Mitsubishi Materials Corp | 2 | |
| 14 | Zhangjiagang Industrial Technology Research Institute Co., Ltd. / Dalian Institute | 2 | |
| 15 | AAFC Energy Technology Co., Ltd. | 2 | |
| 16 | PETOCA | 2 | |
| 17 | Toyota Motor Corporation | 2 | |
| 18 | Ioxus Japan Co., Ltd. | 2 | |
| 19 | EPPSCORE | 2 | |
| 20 | Yoshio Masayuki | 2 |
The incumbents’ positions reflect decades of accumulated expertise in electrode materials, cell assembly, and electrochemical system integration. New entrants face both a technical and IP barrier in the core capacitor branches that these leaders have consistently occupied.
Patent publication typically lags filing by 18–24 months, so the most recent periods in this dataset are likely under-counted; the apparent activity level in 2024–2026 should be interpreted with that caveat. Longer-window growth, applicant concentration, and technology-route coverage are therefore more reliable signals than the latest-year bar alone.
Filing Volume Has Eased; Core Capacitor IP Dominates the Technology Mix
The annual filing trend and technology composition charts together reveal a field past its peak activity, concentrated in a well-defined core IPC class with a sparse but diverse set of adjacent branches.
Annual filing trend
Filings peaked around 2017 and have since eased, with sporadic activity rather than a sustained upward trajectory. The most recent years (2024–2026) show low counts that reflect publication lag rather than confirmed future volume — these figures should be treated as preliminary.
↗ Hover for values · click a bar to ask EurekaTechnology composition
H01G (Capacitors) is by far the dominant IPC class, followed at a distance by H01M (Batteries, cells and fuel cells), reflecting the hybrid nature of these devices. All other branches — including B82Y (Nanotechnology), C01B (Inorganic compounds), and C25D (Electroplating) — each account for a small share, indicating that most innovation remains anchored in core capacitor engineering.
↗ Hover for values · click a bar to ask EurekaHighly cited patent families surfaced by the query
Citation-heavy patent families returned by the query. Use this section as citation context, not as a curated list of the most topic-specific patents.
Method for drying electrode pair, method for manuf…
This method for drying an electrode pair includes: a step in which a collector is coated with a positive-electrode material, yielding a positive electrode; a step in which a collector is coated with a negative-electrode material, yielding a negative electrode; a step in which an electrode pair (7) is produced, said electrode pair comprising one or more sets… (excerpt from the patent abstract)
| # | Patent | Citations |
|---|---|---|
| 1 | Electric double-layer capacitor | 361 |
| 2 | Electric double-layer capacitor | 226 |
| 3 | Electric double-layer capacitor | 125 |
| 4 | Active carbon electrode and its manufacturing meth… | 77 |
| 5 | Current collector for non-aqueous electrochemical … | 63 |
| 6 | Secondary power supply | 45 |
| 7 | 一种石墨烯/钛酸锂复合负极材料的制备方法 | 39 |
| 8 | Electric double-layer capacitor | 39 |
Ranked by total forward citations. Citation counts favour older and broadly cited patent families, and broad or adjacent patents may appear when they match the search scope. Treat this section as citation context, not as a curated list of the most topic-specific patents. Some patent titles may be shown in their original, non-English language where an accurate translation could not be guaranteed.
What the Structure Means for R&D Investment Decisions
Japan-centric geographic footprint defines the strategic context. These factors together suggest incremental optimization is the prevailing R&D mode, with selective opportunities in adjacent branches.
Field in Decline — Core Technology Past Peak
The lifecycle stage is Decline, with annual filing volume easing back from a 2017 peak and a recent-window growth rate of –33%. This indicates the foundational IP landscape is largely settled. R&D investments in the core H01G capacitor space face diminishing returns in terms of novel IP position; incremental process and materials improvements are the realistic near-term output.
Lifecycle: DeclineTop Five Hold 40% of the Leading-100 Filer Pool
The top five applicants — Panasonic Holdings, Mitsubishi Electric, Mitsubishi Chemical, ESPEC, and AGC — together represent 40% of the combined patent records among the hundred largest filers. This level of concentration means the IP landscape is defensible by incumbents but not impenetrable; second-tier players with 4–9 patent records each occupy meaningful positions in specific sub-branches.
Moderate concentrationLimited Co-Filing; Mitsubishi Chemical–Toyota Is the Notable Pair
Only two co-applicant pairs are recorded in this dataset: Mitsubishi Chemical and Toyota Motor, collaborating on 2 joint filings, and INAHARA JUNICHI with ESPEC Corp on 1 filing. The scarcity of collaboration signals that most R&D in this space is conducted within single organizations rather than via consortia or cross-sector partnerships — a characteristic of mature, proprietary technology fields.
Low collaboration densityJapan Dominates; U.S. and China Are Secondary Markets
Japan accounts for 52 patent records, making it the primary filing jurisdiction by a wide margin. The United States follows with 23 records and China with 14, while Europe (EPO) holds 8 and South Korea 5. The concentration in Japan mirrors the applicant ranking and reflects where the dominant players are headquartered and where core IP protection is prioritized.
Japan-centricGo beyond the landscape: Eureka’s TRIZ Solution agent breaks down an R&D problem and returns patented concept solutions, each with a technical approach and cited patent & literature evidence.
| Applicant | Collaborator | Co-filings |
|---|---|---|
| Mitsubishi Chemical Corp | Toyota Motor Corporation | 2 |
| INAHARA JUNICHI | ESPEC Corp | 1 |
Co-filing pairs, ranked by the number of jointly-filed patent families.
Panasonic Leads on Volume; Mitsubishi Entities Cover Electrode Materials
The leader tier is anchored by three large Japanese corporations with overlapping but distinct technical emphases. Applicant momentum data is not available in this dataset, so trajectory reads are based on technology focus and ranking position alone.
Panasonic Holdings Corp
Panasonic Holdings leads with 15 patent records, concentrating its portfolio in H01G 11 (electrochemical capacitors), H01G 9 (electrolytic capacitors), and H01M 10 (secondary batteries). This breadth across both capacitor sub-types and battery-adjacent classes reflects a systems-level approach to hybrid energy storage. Applicant momentum data is not available for this period.
15 patent recordsMitsubishi Electric Corp
Mitsubishi Electric Corp holds 9 patent records, with emphasis on H01G 11 (electrochemical capacitors), H01M 4 (electrode materials), and H01G 9. Its focus on electrode material development alongside core capacitor IP positions it as a materials-oriented challenger. Mitsubishi Chemical Corp shares the same record count and similarly emphasizes H01G 11 and C01B 31 (inorganic compounds), adding a chemistry-layer perspective. Applicant momentum data is not available for this period.
9 patent recordsUnder-Served Branches Adjacent to the Core Capacitor Domain
Several IPC branches appear in the corpus at low counts relative to the dominant H01G class. These represent observations of relative sparsity; where there is also a plausible technical rationale and realistic entry path, they may warrant closer R&D attention.
B82Y · Nanotechnology Applications
With only 8 patent records and a 4% share of the corpus, nanotechnology applications remain sparsely covered relative to the core capacitor IP. Nanostructured carbon materials — graphene, carbon nanotubes — are technically well-suited to enhancing electrode surface area and ion transport in hybrid capacitors. AGC Inc is the only applicant in the ranking with visible B82Y activity. An entrant with nanomaterials synthesis capability could find freedom to operate in this sub-space, though the overall field’s decline-stage lifecycle tempers the near-term commercial urgency.
Search this in Eureka →C25D · Electroplating and Electroforming
C25D accounts for only 6 patent records at a 3% share. Electroplating and surface treatment of current collectors is a technically relevant step in capacitor manufacturing — UACJ Corp is the sole applicant in the ranking with a clear C25D focus (4 records). The sparse filing density here suggests that current-collector surface engineering remains a relatively open sub-area within an otherwise mature field, with a realistic entry path for materials or process specialists already active in metal foil or surface-treatment manufacturing.
Search this in Eureka →How Leading. Applicants Differ by Technology Route
Strength of each leader across the main technology routes.
| Player | H01G 11 · Capacitors | H01G 9 · Capacitors | H01M 4 · Batteries, cells & fuel cells | H01M 10 · Batteries, cells & fuel cells | B82Y 99 · Nanotechnology applications |
|---|---|---|---|---|---|
| Panasonic Holdings Corp | Strong · 15 | Strong · 12 | Absent | Strong · 8 | Absent |
| Mitsubishi Electric Corp | Strong · 9 | Moderate · 4 | Strong · 7 | Moderate · 2 | Absent |
| Mitsubishi Chemical Corp | Strong · 9 | Moderate · 4 | Absent | Absent | Absent |
| ESPEC Corp | Strong · 4 | Strong · 3 | Strong · 3 | Moderate · 2 | Absent |
| AGC Inc | Strong · 7 | Moderate · 2 | Absent | Absent | Moderate · 2 |
| Semiconductor Energy Laboratory Co., Ltd. | Strong · 5 | Strong · 5 | Absent | Absent | Absent |
Frequently asked questions
Panasonic Holdings Corp leads with 15 patent records in the applicant ranking, ahead of Mitsubishi Electric Corp and Mitsubishi Chemical Corp, each with 9 patent records.
The field is assessed as being in Decline, with annual filing volume easing back from a 2017 peak and a recent-window growth rate of -33%. The foundational IP landscape is largely established.
Japan is the dominant jurisdiction with 52 patent records, followed by the United States with 23, China with 14, Europe (EPO) with 8, and South Korea with 5.
H01G (Capacitors) is the dominant class with 108 patent records, followed by H01M (Batteries, cells and fuel cells) with 51. All other classes are present at significantly lower counts, reflecting the core nature of capacitor engineering in this space.
Collaboration is limited. Only two co-applicant pairs are recorded: Mitsubishi Chemical and Toyota Motor with 2 joint filings, and INAHARA JUNICHI with ESPEC Corp with 1 joint filing. The field is predominantly driven by single-organization R&D.
B82Y (Nanotechnology applications) and C25D (Electroplating and electroforming) each have 6–8 patent records and represent the sparsest adjacent branches with plausible technical relevance to electrode and current-collector engineering in hybrid capacitors.
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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.
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