Flow Battery Stack Patents: Who Leads, Where the Gaps Are 2026
- Concentrated at the top. the five most active filers account for 50.0% of all 146 records in scope, and the ranked ten account for 74.7%.
- Filing has cooled sharply. activity peaked at 31 records in 2017 and had fallen to 2 by 2022, with no rebound visible before the data cut-off.
- Claim space is narrow but deep. 97.3% of records sit in H01M, with only small, scattered activity in catalysis, electrolytic production and computational tooling.
Filing growth compares 2021 (4 records) with 2024 (9) — 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 146 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This review covers 146 published records matching flow battery stack, flow field design and electrode felt claims combined with technical terms such as pressure drop, shunt current, membrane crossover and coulombic efficiency. The scope spans 2015 through the 2026-07-31 data cut-off, and receiving-office activity is led by the United States, followed by Europe, India, the WIPO PCT route, China and Australia.
Publication typically lags filing by around 18 months, so the most recent year in any trend line understates real activity. Read the tail of the trend as incomplete rather than as a genuine drop-off in the current filing year.
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 146 records: how filing activity has moved year over year, and how those records distribute across IPC subclasses.
A peak in 2017, then a decline
Filings hit their high point at 31 records in 2017. By the 2022 midpoint the annual count had fallen to 2, and the trend stays flat through to the cut-off — a pattern of a technology that had an early burst of claiming activity rather than sustained, rising interest.
H01M dominates; everything else is a minority add-on
97.3% of the 146 records carry an H01M battery/cell/fuel-cell classification. The next largest classes — B01J catalysis and process work, C01G metal compounds, C25B electrolytic production and G06F data processing — each sit at single-digit shares, and G16C computational chemistry and B21D sheet-metal working are smaller still. Because records can carry multiple classes, these shares add up to more than 100% of the record total; they are not mutually exclusive buckets.
Shares are the percentage of the 146 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Flow Battery Stack and Flow Field Design with Eureka
This page is one run against one query. Ask Eureka your own question about flow battery stack and flow field design and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records in the corpus
Unique Guided frame design redox flow battery stack for improved performance
A redox flow battery stack built from repeating flow-frame, bipolar-plate, electrode and ion-exchange-membrane units. The filing claims a cell flow frame that gives uniform electrolyte flow distribution and low pressure drop, aiming to hold efficiency stable across the stack rather than trading power density for pumping losses.Filed by Vflow Tech Pte Ltd, dated 2022-05-24.
View full filing| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20130011704A1 | Redox Flow Battery System with Multiple Independent Stacks | 97 |
| 2 | US20010041281A1 | Flow fields for supporting fluid diffusion layers in fuel cells | 89 |
| 3 | US20040265675A1 | Fuel Cell Flow Field Design | 42 |
| 4 | US20060093891A1 | Flow field design for high fuel utilization fuel cells | 40 |
| 5 | US20120321920A1 | System and method for operating a flow battery system at an elevated temperature | 39 |
| 6 | WO2012094674A2 | Redox flow battery system with multiple independent stacks | 36 |
| 7 | US6541145B2 | Flow fields for supporting fluid diffusion layers in fuel cells | 35 |
| 8 | US20130071714A1 | Flow battery stack with an integrated heat exchanger | 28 |
| 9 | US20160036060A1 | Composite electrode for flow battery | 24 |
| 10 | US20170288243A1 | High performance redox flow battery stack | 20 |
Citation counts favour older filings simply because they have had longer to accumulate references inside this corpus; treat them as a signal of influence on later filers, not as a ranking of current commercial importance.
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 a filing decision
Three read-outs from the same dataset, each pointing at a different practical question: where claim density already sits, where activity has gone quiet, and where the classification spread suggests real but thin adjacent interest.
Core stack and flow-field claims are crowded at the top
Half of all records in scope belong to just five assignees, and three-quarters belong to ten. A new entrant filing a broad stack-architecture or flow-field claim is filing directly against a small group that already holds the majority position.
The field's early burst has not been repeated
The 2017 peak of 31 records looks like a period of active staking-out rather than a sustained wave. Recent-year filing counts for the leading assignees sit at zero in the latest year, which is consistent with the overall decline but should be read against the 18-month publication lag.
Adjacent classes are present but thin
Catalysis (B01J), metal compounds (C01G), electrolytic production (C25B) and data processing (G06F) each appear in only a handful of records. That is too small a footprint to call a trend, but it marks where cross-disciplinary claims exist without being contested.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to flow battery stack and flow field design, with the prior art for and against each one.
Who holds the ground, and where it opens up
The ranked leaders sit alongside a long tail of single- or few-filing entrants. Co-filing pairs point to a small number of tight collaborations rather than a broad ecosystem.
One filer well ahead of the field
The leading assignee holds 22 records, noticeably more than the fifth-place holder's 8 and the tenth-place holder's 7. That gap suggests a genuine head start on stack and flow-field IP rather than a crowded first tier.
Co-filing is concentrated in a handful of pairs
Ten co-assignee pairs appear in the dataset. The strongest, at 22 shared records, links the two Chinese research and technology entities that also lead the individual ranking, pointing to one dominant institutional partnership rather than a wide collaborative network.
Most assignees hold very few records
The ranking covers 69 companies in total. With the top ten already accounting for 74.7% of all 146 records, the remaining ranked assignees are mostly single- or double-filing entrants — useful signals of niche activity but not sources of blocking portfolios.
| Assignee | Recent year | YoY |
|---|---|---|
| Beijing Zhongkaihongde Technology Co., Ltd. | 0 | — |
| Institute of Process Engineering, Chinese Academy of Sciences | 0 | — |
| General Electric Company | 0 | — |
| United Technologies Corporation | 0 | — |
| Pratt & Whitney Rocketdyne, Inc. | 0 | — |
| Hui Kang Life Technology Co., Ltd. | 0 | — |
| EnerVault Corporation | 0 | — |
| TAPPI MAURIZIO | 0 | — |
Next steps for an R&D or IP team
The dataset points to where filing has already concentrated and where it has gone quiet. What a team does with that depends on whether it is scouting a chemistry, checking freedom to operate, or looking for a licensing partner.
Check freedom to operate around the leader's claims
With one assignee holding 22 records and the top five holding half of all 146, a new stack or flow-field filing should start by mapping claim scope against that concentration rather than the field average.
Explore assignee claims in EurekaTest the under-claimed sub-areas before committing scope
Small IPC shares in catalysis, electrolytic production and computational tooling suggest claim room, but thin data also means fewer prior-art anchors to design against.
Run a white-space search in EurekaRe-check momentum once the lag clears
Recent years understate true filing activity by roughly 18 months of publication lag. Treat the apparent 2022 slowdown as provisional until later data cuts confirm it.
Track filing trends in EurekaCommon questions about flow battery stack and flow field design patents
One assignee leads the 146-record dataset with 22 records, well ahead of the fifth-ranked holder at 8 and the tenth-ranked holder at 7. The top five assignees together account for 50.0% of all records in scope, and the top ten account for 74.7%. Beyond that group, the ranking runs to 69 companies in total, most holding only one or two records, so the field has a clear leading tier and a long tail rather than an even spread.
No — filing peaked at 31 records in 2017 and had fallen to 2 by the 2022 midpoint, with no rebound visible before the 2026-07-31 data cut-off. Recent-year momentum for the leading assignees also shows zero filings in the latest year. Because publication typically lags filing by about 18 months, the most recent years are understated, but the multi-year decline from the 2017 peak is a genuine pattern, not just a lag artefact.
97.3% of the 146 records classify under H01M, the core batteries and fuel cells subclass, which is expected given the search scope. Smaller shares fall into B01J (catalysis and chemical processes, 6.8%), C01G (metal compounds, 2.7%), C25B (electrolytic production, 2.7%) and G06F (data processing, 2.7%), with G16C computational chemistry and B21D sheet-metal working smaller still. These adjacent classes show real but thin activity — worth checking before assuming the space is open, not proof that it is uncontested.
The strongest signals point to shunt-current suppression geometry, electrode felt activation treatment, bipolar plate flow-channel machining, computational flow-field optimisation and elevated-temperature electrolyte rebalancing — areas that show up only in small IPC shares such as B01J, C25B and G06F rather than in the dominant H01M claim set. That does not guarantee freedom to operate, since thin data can also mean thin prior art to test scope against, but it marks where the 146-record set is not yet dense with claims.
Mostly independently — the dataset contains only 10 co-assignee pairs against 146 total records. The strongest pair, with 22 shared records, links the two leading Chinese research and technology entities that also top the individual assignee ranking, suggesting one dominant institutional partnership rather than a broad collaborative network. Most other assignees, including several individual inventors named in the data, file solo.
Research Flow Battery Stack and Flow Field Design in depth with Eureka
Go past this page: query the whole flow battery stack and flow field design 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.