Phase Change Thermal Storage Patents: Leaders & Trends 2026
Filing growth compares 2021 (1,296 records) with 2024 (1,405) — 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 19,865 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Phase change thermal energy storage uses a material’s latent heat of fusion — melting and solidifying rather than a temperature swing — to store and release heat on demand. The dataset behind this page spans 19,865 published records filed between 2015 and mid-2026, drawn from a search string that pairs “phase change storage” language with thermal-energy-storage, battery, energy-storage and electrochemical-cell context terms. That combination pulls in both dedicated thermal-storage hardware and the growing overlap with battery and grid-power classes, which is itself a signal of where the field is heading.
Because publication lags filing by roughly 18 months, the most recent one or two years in any trend understate real filing activity; treat 2025 and 2026 figures as still filling in rather than as a slowdown.
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Filing trends and technology composition
Two views of the same 19,865 records: how filing volume has moved year over year, and which IPC subclasses the claims actually sit in.
Filing volume climbed through the last complete year
Annual filings rose from 1,022 in 2017 to a peak of 1,496 in 2022, and the 2021-to-2024 window shows an 8% increase (1,296 to 1,405 records) even after the growth rate off the peak. 2025 and 2026 figures will rise as later publications catch up, given the typical 18-month lag between filing and publication.
Heat-exchange hardware outweighs storage chemistry
F28D (heat-exchange apparatus) touches 19.3% of records and C09K (materials for miscellaneous applications, including phase change compounds) touches 14.4% — both ahead of the battery-cell class H01M at 9.9% and grid-power class H02J at 9.7%. Since a record can carry several IPC classes, these shares add up to more than 100% of the 19,865 records in scope; they show breadth of claim activity, not a single ranked total.
Shares are the percentage of the 19,865 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Thermal Energy Storage: Phase Change Storage Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about thermal energy storage: phase change storage patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaA representative filing and the most-cited prior art
High-efficient central chiller plant system with variable load by phase change material thermal energy storage
Filed by Boca International Limited and published December 2022, this filing pairs a refrigeration unit operating at its highest coefficient of performance with a phase change thermal energy storage bank. When refrigeration output exceeds cooling demand, the phase change store absorbs the surplus; when output falls short, the store releases it back, letting operators set dispatch strategy from usage statistics rather than sizing the chiller for peak load alone.Chosen as representative of the claim style in this space: a mechanical refrigeration system with a phase change store as a dispatchable buffer, rather than a claim over the phase change material itself.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20030187338A1 | Analyte monitoring device and methods of use | 1,479 |
| 2 | WO1999056613A1 | Analyte monitoring device and methods of use | 1,211 |
| 3 | US20120235636A1 | Systems and methods for providing positioning freedom, and support of different voltages, protocols, and powe… | 1,197 |
| 4 | US6595929B2 | System for monitoring health, wellness and fitness having a method and apparatus for improved measurement of … | 869 |
| 5 | US20070186923A1 | Drug storage and dispensing devices and systems comprising the same | 548 |
| 6 | US20100076615A1 | Systems, devices and methods for electricity provision, usage monitoring, analysis, and enabling improvements… | 547 |
| 7 | US20100085325A1 | Combination touch and transducer input system and method | 535 |
| 8 | US20030120183A1 | Assistive clothing | 526 |
| 9 | US6980092B2 | Vehicle rearview mirror assembly incorporating a communication system | 469 |
| 10 | US20120043818A1 | Switching Circuits For Extracting Power From An Electric Power Source And Associated Methods | 454 |
Citation counts favour older filings simply because they have had longer to accumulate citations inside this corpus; read them as a signal of influence on later filings, 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
Four read-outs from the ranking, the trend and the class mix that matter more than the raw totals.
No single company controls the claim space
The leading assignee holds 186 records and the fifth-ranked holds 98 — a fast drop-off rather than a plateau. Combined, the top five account for only 3.4% of all records in scope and the top ten for 5.5%, which points to a fragmented field of specialists, universities and industrial players rather than one dominated by a handful of blocking portfolios.
Filing activity is still rising, not plateauing
Volumes grew from 1,296 records in 2021 to 1,405 in 2024, an 8% increase over that span, after peaking at 1,496 in 2022. That peak-then-dip pattern inside an overall rising trend is typical when a technology moves from lab-stage claims toward system-integration claims; it is not evidence of the field cooling off.
Hardware integration outpaces storage-chemistry claims
F28D heat-exchange apparatus and C09K storage materials lead the class mix at 19.3% and 14.4% of records respectively, ahead of battery-cell class H01M at 9.9%. That ordering suggests most current claim activity is about moving heat into and out of a phase change store efficiently, not about the storage material's chemistry alone.
Filing activity is heavily routed through China
China accounts for 9,764 records, more than three times the United States total of 3,002, with Europe, WIPO/PCT, India and South Korea trailing further behind. Anyone benchmarking freedom to operate needs to check Chinese-language prior art directly rather than relying on English-language search alone.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to thermal energy storage: phase change storage patent landscape, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Sunamp Limited | FIELD JOHN | 4 |
| Sunamp Limited | BISSELL ANDREW | 4 |
| Xi'an Jiaotong University | Xi'an Thermal Power Research Institute Co., Ltd. | 4 |
| Southeast University | Jiangsu New Energy Development Co., Ltd. | 3 |
| Tianjin University | China Aerospace Construction Engineering Group Co., Ltd. | 3 |
| Tianjin University | China Aerospace Construction Group Co., Ltd. | 3 |
| General Electric Company | GE GRID SOLUTIONS LLC | 2 |
| Southeast University | China Shipbuilding Group No. 703 Research Institute | 2 |
Co-assignment activity is thin — only 10 co-assignee pairs recur in this corpus, the strongest appearing four times each, mostly linking individual inventors to a single company or one university to one affiliated research institute. That pattern is consistent with a field still dominated by single-assignee filings rather than joint-venture R&D.
Where to take this next
The dataset points to specific follow-up questions rather than a single conclusion.
Map claim overlap with battery portfolios
With H01M battery-cell claims already present in 9.9% of records, portfolios that combine phase change storage with electrochemical cells are worth tracking as their own sub-cluster rather than folding into general thermal storage analysis.
Explore battery overlap in Eureka →Watch the 2025–2026 filing catch-up
Because publication lags filing by about 18 months, the apparent drop after 2024 is a reporting artefact, not a real decline; re-check this trend once later years finish publishing.
Track filing trends in Eureka →Look past the top ten assignees
With the top ten holding only 5.5% of records, most of the useful competitive signal sits in the long tail of single- and few-filing entrants, including universities and regional research institutes.
Search the full assignee ranking in Eureka →Common questions about phase change thermal storage patents
The ranking covers 100 assignees, and it is a fragmented field rather than one led by a dominant player. The single leading assignee holds 186 records, dropping to 98 records by fifth place, and the top five together hold only 3.4% of all 19,865 records in scope. That spread includes specialist thermal-storage firms, large industrial conglomerates, and universities and research institutes, particularly from China, so competitive tracking needs to look well beyond the first few names on any ranking.
Yes, through the last year that can be treated as complete. Filings rose from 1,296 records in 2021 to 1,405 in 2024, an 8% increase, after touching a peak of 1,496 in 2022. Figures for 2025 and 2026 look lower only because publication typically lags filing by about 18 months, so those years are still filling in rather than showing a real slowdown.
Heat-exchange hardware leads the class mix: F28D (heat-exchange apparatus) appears in 19.3% of the 19,865 records in scope, ahead of C09K storage materials at 14.4%. Battery and grid-power classes (H01M and H02J) each sit near 9.7 to 9.9%, and domestic heating, refrigeration, solar collection and air conditioning classes each account for under 6%. Because records can carry multiple IPC classes, these shares overlap rather than summing to 100%, and the pattern indicates most current claim activity centres on moving heat efficiently rather than on the storage chemistry alone.
China's receiving office accounts for 9,764 of the records in this dataset, more than three times the United States total of 3,002. Europe (EPO), WIPO/PCT filings, India and South Korea follow at smaller volumes. Anyone assessing freedom to operate in this space should expect a large share of relevant prior art to be in Chinese-language filings and plan search and translation resources accordingly.
This filing, from Boca International Limited and published in December 2022, claims a chiller plant architecture that pairs a refrigeration unit running at its optimum coefficient of performance with a phase change thermal store used as a dispatchable buffer. It is a system-integration and control-strategy claim rather than a claim over a specific phase change material, so it constrains how the storage buffer is dispatched alongside refrigeration equipment more than it constrains material composition. Designers working on the materials side, or on integration architectures that dispatch storage differently, may have more room to operate than those replicating this specific chiller-plus-buffer control logic.
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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.