Thermochemical Heat Storage Patents: Leaders & Trends 2026
Filing growth compares 2021 (66 records) with 2024 (101) — 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 951 records in scope (CR5), not by the ranked leaders only.
What the thermochemical heat storage patent record shows
Thermochemical heat storage covers systems that bank thermal energy in a reversible chemical or physical transformation rather than as sensible or latent heat alone. The 951 records in this dataset span heat-exchange hardware, storage materials, solar thermal collection and power-plant integration, reflecting a technology that sits at the intersection of materials chemistry and industrial heat engineering rather than a single well-defined component category. Publication lags filing by roughly 18 months, so the most recent filing years in any trend chart understate actual activity.
Filing activity is led by research institutes and universities alongside a handful of industrial groups, with receiving offices concentrated in China and a smaller but meaningful share filed through the US, European and PCT routes. That split points to a field where core process and materials work is being established domestically first, with international filing reserved for a narrower set of assignees.
Filing trends and technology composition
The charts below draw on all 951 records in scope, tracking how filing volume has moved year over year and how the technology splits across IPC subclasses.
A decade of rising filing activity
Annual filings climbed from 62 in 2017 to a peak of 151 in 2025, with the 2021-2024 span alone showing a 53% increase (66 to 101 records). Because publication trails filing by about 18 months, the 2025 and 2026 figures are still filling in and should not be read as a plateau or decline.
Heat-exchange hardware dominates the claim space
F28D heat-exchange apparatus appears in 46.2% of the 951 records, roughly four times the share of any single materials or solar-collector class. C09K storage materials (17.4%), F01K power-plant integration (10.7%), B01J catalysis/process (10.4%) and F24S solar collectors (10.4%) form a second tier, with H01M battery-adjacent filings at 7.9% showing where thermochemical storage overlaps electrochemical storage.
Shares are the percentage of the 951 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
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Power generation system using a thermochemical energy storage system or a thermal energy storage system
Filed by RedoxBlox, this March 2026 publication describes a power generation system integrated with a thermal or thermochemical energy storage device, where an electrical current is passed directly through the storage medium to raise its thermal or thermochemical storage capacity.The claim scope centres on combining direct electrical charging with a thermochemical or thermal storage medium inside a power-generation loop, rather than on the storage material itself.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20050166869A1 | Liquid piston internal combustion power system | 82 |
| 2 | US7347049B2 | Method and system for thermochemical heat energy storage and recovery | 77 |
| 3 | US20170362090A1 | High temperature thermochemical energy storage system | 66 |
| 4 | US20040261415A1 | Motor-driven compressor-alternator unit with additional compressed air injection operating with mono and mult… | 58 |
| 5 | US20060080960A1 | Method and system for thermochemical heat energy storage and recovery | 56 |
| 6 | EP3324018A1 | Integrated calcination-carbonation system and closed-loop co2 cycle for thermochemical energy storage and ele… | 50 |
| 7 | US4386501A | Heat pump using liquid ammoniated ammonium chloride, and thermal storage system | 46 |
| 8 | US20130101502A1 | Reducing and/or harvesting drag energy from transport vehicles, including for chemical reactors, and associat… | 41 |
| 9 | US6022487A | Heat-transfer concentrate, method of manufacturing it and its use as well as a latent-heat accumulator making… | 41 |
| 10 | WO2017001710A1 | Integrated calcination-carbonation system and closed-loop co 2 cycle for thermochemical energy storage and el… | 39 |
Citation counts inside a searched corpus favour older, foundational filings — read them as a signal of influence on later work, not as a marker of current commercial relevance.
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Beyond raw counts, the ranking and co-filing data point to a field where a handful of institutes anchor most of the activity while collaboration remains limited to a few tight pairs.
Five assignees hold nearly a quarter of the field
The top five assignees combined account for 222 records, 23.3% of the 951 in scope, with the leader alone holding 69. The next five bring the top-ten combined share to 35.5% (338 records) — concentrated at the top but with a long tail of single- and few-filing entrants below rank ten.
Heat exchangers, not materials, are the busiest claim surface
Heat-exchange apparatus (F28D) touches nearly half of all records, well ahead of storage materials (C09K, 17.4%) and solar collectors (F24S, 10.4%). A filing strategy built purely around new storage chemistries is competing in a smaller, less crowded slice of the landscape than one touching heat-exchanger hardware.
Collaboration is narrow and institute-led
Only ten co-assignee pairs appear in the dataset, and the strongest is a 24-record partnership between two Chinese power-research entities, followed by a 20-record Dutch-university pairing. Most assignees file solo, which limits how much freedom-to-operate risk is shared across organisations.
Growth is real, but read the last two years with caution
Filings rose from 66 in 2021 to 101 in 2024, the last year the dataset treats as complete. 2025's headline figure of 151 and 2026's partial count should not be read against 2024 as a trend break in either direction — publication lag means both years are still filling in.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to thermal energy storage: thermochemical heat storage patent landscape, with the prior art for and against each one.
Where to take this next
The dataset points to specific questions worth running down before committing R&D or filing budget.
Check freedom-to-operate around heat-exchanger claims
With F28D touching 46.2% of records, any new thermochemical storage hardware is likely to sit near existing heat-exchanger claims regardless of the storage chemistry used.
Explore claim scope in EurekaWatch the leading institutes' filing pace, not just their totals
A handful of assignees hold a disproportionate share of records; tracking their year-over-year filing behaviour is more informative than the cumulative rank alone.
Track assignee activity in EurekaReassess the H01M overlap with electrochemical storage
7.9% of records already bridge thermochemical and battery classifications, a boundary worth monitoring as hybrid storage architectures mature.
Map cross-class filings in EurekaCommon questions on thermochemical heat storage patents
Filing activity is led by research institutes and universities rather than a single dominant commercial player, with the top assignee holding 69 of the 951 records in scope. The top five assignees combined account for 222 records, 23.3% of all records, and the top ten reach 35.5%. Below that concentration sits a long tail of assignees with only a handful of filings each, so the field is far from a two- or three-way race.
Thermochemical heat storage patents claim systems that store energy through a reversible chemical or physical transformation, distinct from sensible heat storage (temperature change in a medium) or latent heat storage (phase change). In this dataset that distinction shows up in the technology mix: heat-exchange hardware (F28D, 46.2% of records) and storage materials (C09K, 17.4%) dominate, while power-plant integration (F01K, 10.7%) and solar collection (F24S, 10.4%) reflect how the stored heat is actually recovered or supplied. Filers should expect prior art searches to cross several IPC subclasses rather than one narrow class.
F28D (heat-exchange apparatus) is the busiest class by a wide margin, appearing in 46.2% of the 951 records in scope. C09K (storage and working materials, 17.4%), F01K (steam and thermal power plant integration, 10.7%), B01J (catalysis and process, 10.4%) and F24S (solar collectors, 10.4%) form a second tier. Because a single record can carry several IPC codes, these shares add up to more than 100% and should be read as overlapping claim surfaces, not a mutually exclusive breakdown.
Filings grew from 62 in 2017 to a recorded peak of 151 in 2025, and the clearest complete-year comparison — 2021 to 2024 — shows a 53% rise from 66 to 101 records. Because publication typically lags filing by around 18 months, the 2025 and 2026 figures in any dataset are still being filled in and should not yet be read as a slowdown or a plateau. On the evidence available through the last complete year, the trend is upward.
The technology composition shows heavy claim density in heat-exchanger hardware and storage materials, but comparatively lighter coverage in the overlap between thermochemical storage and electrochemical battery systems (H01M, 7.9% of records) and in solar-integrated thermochemical collectors (F24S, 10.4% combined with C09K materials work). Assignee concentration also leaves a long tail below the top ten, meaning most of the 100 ranked companies hold only a handful of filings each — a sign that many process-integration and system-control approaches remain unconsolidated. A freedom-to-operate review focused on cross-class filings, rather than any single IPC code, is the more reliable way to locate open ground.
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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.