Phase-Change Thermal Storage Patents: Leaders, Trends & White Space 2026
- Filing has flattened, not grown: activity peaked at 18 families in 2024 after climbing steadily from zero in 2017, with the 2022 midpoint at 13 — the curve is levelling rather than accelerating.
- Claim space concentrates in materials, not hardware: C09K (materials for misc. applications) accounts for 54 of 134 records, more than three times the next-largest subclass, F28D heat-exchange apparatus at 17.
- Filing is genuinely global with no single dominant office: China and the United States each hold 27 receiving-office records, with India close behind at 21 and Europe, Japan and the UK all in double digits.
What this landscape covers
This landscape tracks patent families addressing environmental durability in phase-change thermal storage — materials and constructions engineered against thermal cycling degradation, leakage of the phase-change material after repeated melt cycles, and phase segregation between the storage medium and its stabilizing matrix. The search combines core phase-change material terms with the specific durability failure modes the industry cites most: cycling stability, leakage prevention and segregation resistance.
The 134 families span eight IPC subclasses, from base materials chemistry through polymer additives to heat-exchange hardware and even absorbent-article and battery contexts where phase-change layers appear as a subsystem. That spread signals a durability problem being solved from multiple engineering directions at once, rather than a single dominant design pattern.
Let an AI agent run this analysis on your own technology
Pick a task. Every answer cites the patents behind it.
Filing trend and technology composition
Two views of the same 134 families: how filing activity has moved year over year, and where those families sit across the IPC classification.
Filing trend
Filings rose from zero in 2017 to a peak of 18 in 2024, passing through 13 at the 2022 midpoint. The 2026 figure of 6 is a partial-year count and, given typical 18-month publication lag, understates actual filing activity for the most recent period — the real trajectory beyond 2024 is not yet visible in the published record.
Technology composition
C09K (materials for misc. applications) dominates with 54 records, followed by A61F (implants & prostheses, reflecting phase-change layers used in wearable and medical thermal contexts) at 22, H01M (batteries, cells & fuel cells) at 18, and B01J and F28D tied at 17 each. Polymer-side classes C08L and C08K, plus laminate class B32B, round out the picture — durability engineering here is as much about polymer chemistry and layering as about the phase-change material itself.
Shares are the percentage of the 134 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Phase-Change Thermal Storage Environmental Durability with Eureka
This page is one run against one query. Ask Eureka your own question about phase-change thermal storage environmental durability and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
US20210340423A1 — Stable salt hydrate-based thermal energy storage materials (UT-BATTELLE, LLC, 2021-11-04)
A phase change material composition for latent heat storage is provided. In one embodiment, the phase change material includes a salt hydrate having a melting temperature (Tm) of from 1°C to 100°C as determined in accordance with ASTM E793. The phase change material further includes a stabilizing matrix including a polysaccharide selected from the group of a nanocellulose, a sulfonated polysaccharide, a starch, a glycogen, a chitin, and combinations thereof. A composite article including the phase change material composition is also provided.Filed by a US national laboratory, this record illustrates the polysaccharide-matrix stabilization route to leakage and segregation resistance — one of several material strategies competing in the C09K-heavy claim space.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20120296304A1 | Absorbent Article Containing Apertures Arranged in Registration with an Embossed Wave Pattern | 60 |
| 2 | US20120296303A1 | Absorbent Article having Enhanced Leakage Protection | 55 |
| 3 | US7641812B2 | Thermal insulation with thin phase change layer | 47 |
| 4 | US7704584B2 | Thermal insulation with thin phase change layer | 40 |
| 5 | US20090011171A1 | Thermal Insulation with Thin Phase Change Layer | 29 |
| 6 | US8847002B2 | Absorbent article containing apertures arranged in registration with an embossed wave pattern | 19 |
| 7 | US20080312359A1 | Thermal Insulation with Thin Phase Change Layer | 19 |
| 8 | KR1020140081949A | Battery module for sodium rechargeable battery | 15 |
| 9 | CN111960401A | 一种生物质基相变潜热储能材料及其制备方法 | 14 |
| 10 | US20210340423A1 | Stable salt hydrate-based thermal energy storage materials | 13 |
Citation counts inside a searched corpus favour older records simply by virtue of longer exposure; treat this table as a map of influential prior art, not of current filing priority.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
Put your own technology through the same analysis
Eureka on the web
When you want the answer in the next five minutes.
The agent works the prompt against patents and technical literature, citing every source.
Run your analysis now →MCP server & REST API
When it has to run inside your own pipeline.
Patent search, landscape analysis and assignee resolution as MCP tools. Drop them into any agent framework, or call REST directly.
Browse MCP servers →What the numbers mean for filing strategy
Three patterns stand out once the raw counts are read against each other.
Growth has flattened after a multi-year climb
The rise from zero filings in 2017 to a peak of 18 in 2024, passing through 13 at the 2022 midpoint, describes a technology that built up steadily and has since plateaued rather than accelerated. Because publication lag runs roughly 18 months, the 2025-2026 dip is partly an artifact of records not yet published — but the shape through 2024 is real.
Materials chemistry, not apparatus, is where claims pile up
C09K alone accounts for 40% of the corpus, more than three times the second subclass. Heat-exchange apparatus (F28D) and layered-product constructions (B32B) are comparatively lightly claimed, at 17 and 8 records respectively, suggesting hardware-side durability solutions have more open claim territory than material formulations do.
No single office dominates filing strategy
China and the United States are tied at the top with 27 records each, India follows closely at 21, and Europe, Japan and the UK each hold double-digit counts. This is a genuinely multi-jurisdictional filing pattern rather than one anchored to a single home market.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to phase-change thermal storage environmental durability, with the prior art for and against each one.
Assignee landscape
The recent-year momentum data shows several named assignees dropping to zero filings in the latest year, including one at -100% year-over-year — consistent with the broader plateau in the trend line rather than any single company pulling back sharply.
Recent-year activity has gone quiet across the board
Assignees tracked for momentum, including a battery-materials group logging a -100% year-over-year swing, all show zero filings in the latest year. Given publication lag, some of this is simply pending applications not yet public, but the pattern is broad enough to suggest genuine cooling rather than one firm's retreat.
A small cluster files jointly and repeatedly
One inventor-assignee, Ong Yeinsze, appears in three of the strongest co-filing pairs, each shared with a different named co-assignee at a count of 5. That density around a single hub, against only 10 total co-assignee pairs in the whole corpus, marks a distinct collaborative cluster rather than a broad industry norm of joint filing.
A moderately sized, non-consolidated field
With 134 total families and no single assignee shown in the momentum data holding a runaway lead, ownership of this durability-specific claim space reads as fragmented. That is typical of a problem still being approached from several material and construction angles at once, as reflected in the eight-subclass IPC spread.
| Assignee | Recent year | YoY |
|---|---|---|
| Kimberly-Clark Worldwide, Inc. | 0 | — |
| LG Energy Solution, Ltd. | 0 | -100% |
| Engripp Co., Ltd. | 0 | — |
| ONG YEINSZE | 0 | — |
| NG MEIJIA | 0 | — |
| LEE SANGWOOK | 0 | — |
| KIM DOOHONG | 0 | — |
| Aalto University Foundation | 0 | — |
Where to take this next
The landscape points to specific follow-up work depending on whether the goal is freedom-to-operate, white-space filing, or competitive tracking.
Run a freedom-to-operate screen across C09K
With 40% of the corpus concentrated in one subclass, a formulation-level FTO check against the top-cited records is the first gate before committing to a salt-hydrate or polymer-matrix composition claim.
Explore in EurekaMap the under-claimed construction routes
F28D and B32B carry a fraction of the C09K count. A construction-first claim strategy — encapsulation geometry or heat-exchange integration rather than new chemistry — may face thinner prior art.
Explore in EurekaTrack the Ong Yeinsze co-filing cluster
Three repeated co-assignee pairs around one inventor suggest a coordinated filing programme worth watching for future claim direction in this space.
Explore in EurekaCommon questions
In this landscape it refers specifically to three failure modes engineers claim against: loss of performance under repeated thermal cycling, leakage of the phase-change material once it melts, and phase segregation where the active material separates from its stabilizing matrix over time. These are distinct from claims about raw thermal storage capacity or melting-point selection, which sit in adjacent, broader phase-change material filings. The search underlying this page specifically pairs phase-change material terms with these durability failure-mode terms, so it captures the subset of the field addressing long-term reliability rather than initial performance.
Phase-change materials with durability claims show up as subsystems in unrelated end products: A61F records reflect phase-change layers used in wearable or medical thermal-management contexts, while H01M records reflect thermal buffering inside battery packs. Both areas need the same leakage-prevention and cycling-stability properties as dedicated thermal storage products, so their patents fall inside this search even though the primary application differs. This cross-domain spread is worth checking before assuming a competitor is only active in HVAC-labelled thermal storage.
Filings climbed from zero in 2017 to a peak of 18 families in 2024, passing 13 at the 2022 midpoint, then the visible count drops in 2025 and 2026. Because publication typically lags actual filing by around 18 months, the most recent one to two years are understated in any patent dataset, so the apparent 2025-2026 decline should not be read as confirmed until those years finish publishing. The honest read is that growth has flattened from its earlier climb; whether it turns into an outright decline is not yet determinable from published data.
China and the United States are tied at the top of the receiving-office count with 27 records each, with India close behind at 21. Europe (EPO), Japan and the United Kingdom each hold double-digit counts as well, meaning filing activity is spread across at least six major jurisdictions rather than concentrated in one home market. Anyone doing freedom-to-operate work in this space needs to clear prior art in multiple offices, not just the jurisdiction where their own R&D is based.
Materials chemistry under C09K is the densest area, holding 54 of 134 records, so new composition-of-matter claims there face the thickest prior art. Construction and apparatus routes — heat-exchange integration (F28D) and layered/laminate encapsulation (B32B) — carry far fewer records, 17 and 8 respectively, and represent comparatively open ground for durability solutions built around geometry and containment rather than new chemical formulations.
Research Phase-Change Thermal Storage Environmental Durability in depth with Eureka
Go past this page: query the whole phase-change thermal storage environmental durability corpus yourself, in your own scope.
Every answer comes back with patent numbers you can open.
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.