Lithium-Sulfur Battery Testing Patents: Leaders & Filing Trends 2026
- Filings peaked in 2023 at 58 families, then eased back to 4 recorded so far in 2026 after a sharp climb from near-zero in 2017.
- H01M battery-cell claims account for 99 of 109 families, leaving measurement (G01R) and coating (B05C) as thin, second-tier classes.
- CATL and its subsidiaries form the only tight filing cluster, with the lead filer's latest-year count down 78% year over year and every other named assignee at zero.
Understanding the lithium-sulfur battery testing patent landscape
Lithium-sulfur cells fail in ways lithium-ion cells do not, chiefly through polysulfide shuttle and capacity fade that generic battery-testing methods do not fully capture. This landscape covers 109 patent families filed between 2015 and mid-2026 that specifically claim capacity testing, polysulfide shuttle diagnosis or safety testing for lithium-sulfur chemistry. Filing activity was negligible before 2018, rose steadily through the early 2020s, and peaked in 2023 before cooling.
Most of these families are filed as part of broader battery-cell patents rather than as standalone diagnostic instruments, which shapes where a freedom-to-operate search needs to look and where a first claim in a narrower niche can still land clean.
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Filing trends and technology composition
The trend line and IPC spread below chart 109 patent families filed between 2015 and mid-2026, with the most recent year still filling in as later filings publish.
Filings rose sharply through 2023, then eased
Filings held near zero through 2017, climbed to a midpoint of 8 by 2022, then jumped to a peak of 58 in 2023 before tapering — 2026 shows 4 so far, a partial year understated by the usual 18-month publication lag.
Battery-cell classes dominate; measurement and coating sit second tier
H01M (batteries, cells and fuel cells) accounts for 99 of 109 records, with G01R (electric/magnetic measurement) and B05C (coating apparatus) at 9-10 each, and B32B, H05K and B60R each carrying only one or two records.
Shares are the percentage of the 109 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Lithium-Sulfur Battery Testing and Inspection with Eureka
This page is one run against one query. Ask Eureka your own question about lithium-sulfur battery testing and inspection and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative and most-cited filings
Battery cell, battery, and electrical device
A battery cell, a battery, and an electrical device, and relates to the field of batteries. The battery cell includes a shell and a pressure relief component. The shell has a first wall. The pressure relief component is arranged on the first wall, wherein the pressure relief component includes a first weak portion, the first weak portion defines a predetermined pressure relief region, and the pressure relief component is configured to be capable of cracking along at least a part of the first weak portion during pressure relief of the battery cell. The pressure relief component further includes a second weak portion, and the second weak portion is configured to guide at least a part of the pressure relief crack.Filed by Contemporary Amperex Technology Co., Limited, 2026-05-21 — the most recent record in this dataset.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20250070168A1 | Battery cell, battery, and electrical device | 4 |
| 2 | WO2025188417A2 | Methods for forming integrated spray-on aramid nanofiber separator-electrode components for high throughput b… | 2 |
| 3 | US20230344024A1 | Base, voltage sampling assembly, and voltage testing apparatus | 2 |
| 4 | EP4672469A1 | Battery cell, battery and electric device | 1 |
| 5 | US20230275204A1 | Secondary battery, battery module, battery pack, and electric apparatus | 1 |
Citation counts favour older records in the corpus and should be read as a signal of influence, not current relevance.
Publication numbers are shown where the record carries one (5 of 5 rows); clicking a row searches Eureka by that number.
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Three patterns stand out once the 109 families are broken down by class, year and assignee — each has a direct read for where to file and where to watch.
Testing claims ride inside battery-cell patents
Nearly all filings classify under H01M rather than a dedicated measurement or diagnostic class, meaning testing methods are typically bundled into broader cell-design patents. A search limited to instrumentation classes like G01R would miss most of the relevant art.
Filing activity has cooled since 2023
After years of near-zero activity through 2017 and a slow climb to 8 by 2022, filings spiked to 58 in 2023 and have since dropped off sharply. Publication lag means 2025-2026 figures will firm up, but the shape already looks like a post-peak plateau.
One cluster leads, everyone else has stopped
The CATL group is the only assignee still filing in the most recent year, and even its volume is down sharply from prior activity. Every other named assignee, including a Michigan-linked university filer and an Asahi Kasei separator entity, shows zero filings in the latest year.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to lithium-sulfur battery testing and inspection, with the prior art for and against each one.
Who is filing, and where the claim space is still open
A single filing cluster accounts for most recent activity; everyone else named in the ranking has gone quiet in the latest year, which changes how a competitive-watch list should be built here.
CATL and subsidiaries
The CATL group, including a Hong Kong-registered affiliate and a Shenzhen-based future-energy subsidiary, forms the only assignee cluster with sustained filing activity, and the strongest co-assignee pairing in the dataset links two entities within this group.
University of Michigan Board of Regents
An academic assignee appears in the ranking but shows no filings in the most recent year, consistent with a research-stage contribution rather than an ongoing commercial filing programme.
Asahi Kasei battery-separator entities
Two Asahi Kasei-linked assignees, one specific to battery separators, appear in the ranking with no recent-year activity, suggesting separator-side testing claims were filed earlier in the window rather than currently.
| Assignee | Recent year | YoY |
|---|---|---|
| Contemporary Amperex Technology Co., Ltd. (CATL) | 4 | -78% |
| CATL New Energy Technology (Hong Kong) Co., Limited | 0 | — |
| Ningde Amperex Technology Limited (ATL) | 0 | -100% |
| Shenzhen CATL Future Energy Technology Co., Ltd. | 0 | -100% |
| The Regents of the University of Michigan | 0 | -100% |
| Asahi Kasei Battery Separator Corporation | 0 | -100% |
| Asahi Kasei Corporation | 0 | — |
| CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LI HK | 0 | — |
Where to take this research next
The filing data points to a narrow, cooling field with one active cluster — the next steps depend on whether the goal is freedom-to-operate, licensing or a new filing.
Check freedom-to-operate against the CATL pressure-relief family
The lead assignee's claims on two-tier weak-portion vent structures are the densest single claim cluster in this dataset and worth a dedicated clearance search before any cell-safety design finalises.
Run a claim comparison in EurekaScope a filing in polysulfide-specific diagnostics
Generic capacity and safety testing dominate the corpus, but chemistry-specific shuttle diagnosis is thin, leaving room for a narrowly drafted first claim in that niche.
Explore white space in EurekaTrack the next 18 months of publications
Because publication lags filing, the 2025-2026 dip may partly reverse as pending applications surface; a standing watch on this search string will catch that shift early.
Set up monitoring in EurekaCommon questions about Li-S battery testing patents
Most filings sit in H01M, the general battery-cell classification, which holds 99 of the 109 families in this dataset. A smaller group falls under G01R for electric and magnetic measurement instrumentation, and B05C for coating-apparatus claims tied to electrode or separator manufacturing checks. This concentration means testing-method claims are usually filed as part of a broader cell or module patent rather than as standalone instrumentation patents, so searching H01M alone will miss the measurement-specific filings in G01R.
Filing activity in this dataset is concentrated around a small cluster of related Chinese entities, with the CATL group (including its subsidiaries) showing the most recent-year activity, four filings in the latest year, though that represents a 78% year-over-year decline from an earlier peak. A University of Michigan-linked filer and an Asahi Kasei battery-separator entity also appear in the ranking but show no filings in the latest year. The overall pattern is a leading cluster followed by a long tail of low-volume or single-filing entrants.
Filing volume peaked in 2023 at 58 records after several years of near-zero activity, and has declined since, with only 4 filings recorded so far in 2026. Because publication typically lags filing by around 18 months, the 2025 and 2026 figures are understated and will rise as later applications publish. Even accounting for that lag, the trajectory from a 2023 peak looks like a plateau or slowdown rather than continued acceleration.
Polysulfide shuttle is the dominant degradation mechanism specific to lithium-sulfur chemistry, where dissolved polysulfide species migrate between electrodes and cause capacity fade and self-discharge. Diagnosing it distinctly from generic lithium-ion capacity fade requires chemistry-specific sensing or test protocols, which is a narrower and less-filed claim area than general capacity or safety testing in this dataset. That gap makes it one of the more promising areas for a first-mover claim, since broad safety-testing and capacity-testing language already dominates the corpus.
The European Patent Office receives the largest share of filings in this dataset at 59, followed by the United States at 33, with smaller counts through Austria, Germany, WIPO's PCT route and Canada. This EPO-heavy pattern suggests filers are prioritising European protection for testing and inspection methods, which is worth noting when assessing freedom-to-operate for products destined for the European market specifically.
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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.