Flow Battery Membrane Patents: Who Leads, Where the Gaps Are 2026
Flow battery membrane and separator patents: mapping who files, what they claim, and where the field is still open
Filing has cooled from its 2023 peak of 326 records, with 2021's 277 records dropping to 197 by 2024 — a 29% pullback over that span, not a collapse. Filings rose from 128 in 2017 to a peak of 326 in 2023. The most reliable recent comparison is 2021 (277) against 2024 (197), a 29% decline — a real cooling in disclosed activity, though 2025 and 2026 figures will keep revising upward as later publications catch up to their filing dates.
- 1AGC INC3.1%
- 2CALERA CORP2.9%
- 3VERDAGY INC2.5%
- 4LOCKHEED MARTIN ADVANCED ENERGY STORAGE LLC2.0%
- 5EVOQUA WATER TECHNOLOGIES LLC2.0%
See the full membranes and separators for flow batteries analysis in Eureka
- The complete ranking, not just the top five
- Every IPC branch with its share of the corpus
- The most-cited records, and where claim space is still thin
Common questions about flow battery membrane patents
Who holds the most patents on flow battery membranes?
No single company dominates this field: the leading assignee holds 134 records out of 4,363 in scope, and the top 5 assignees combined account for only 12.4% of all records. The remaining activity is spread across a ranked list of 100 companies with a long tail of smaller filers. This means competitive tracking needs to look well beyond the top few names to get an accurate picture of who is active.
Is flow battery membrane patent filing growing or slowing down?
Filings peaked at 326 records in 2023 and fell to 197 by 2024, a 29% decline from 2021’s 277 records over the only recent three-year window where publication data is essentially complete. That is a real cooling from the 2023 peak, but not evidence of the field shrinking overall, since 2025 and 2026 counts are still artificially low due to the roughly 18-month lag between filing and publication. Treat the last one to two years of any trend chart as a floor, not a final figure.
What technology areas do flow battery membrane patents actually cover?
Battery cell and hardware claims (IPC class H01M) appear in 46.9% of the 4,363 records, the largest single class, but separation processes (B01D, 21.1%), polymer processing (C08J, 18.9%) and electrolytic production (C25B, 18.8%) each cover close to a fifth of records too. Because a single patent can carry several IPC codes, these numbers overlap rather than sum to 100%, which is the expected pattern for a field that spans materials chemistry, separation engineering and cell design at once.
Disclaimer. This analysis is based on Patsnap Eureka data drawn from a limited snapshot of global patent records and is provided for general information and reference only. Patent data carries inherent limitations — recent filings are under-counted because of publication lag, counts may be on a record or family basis, classification and applicant-name data may contain errors or duplicates, and the underlying search query defines the scope shown — so the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing here is an exhaustive prior-art, novelty, freedom-to-operate or validity search, nor does it constitute legal, financial or professional advice, and it should not be relied upon as such. Verify independently and review with qualified patent and legal professionals before acting on it.
Method: Filing trend and technology composition. Derived from a Patsnap search on Membranes and Separators for Flow Batteries covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish. Every share divides by all records in scope. Data: Patsnap Eureka. See the full landscape report.