① What’s the Story
The moment the 46mm-diameter cylindrical cell sheds its label as a “next-generation standard format” and actually mounts onto mass-production lines, the tabless electrode patent underpinning that standard has come under investigation by the U.S. International Trade Commission (ITC). Three pieces of news confirmed this week — AESC starting mass production of the 46120 cell, the opening of ITC Investigation No. 337-TA-1518 between LG Energy Solution and China’s EVE Energy, and Korean robotics firm JS Robotics’ KRW 33.26 billion overseas secondary-battery automation-equipment supply contract — may look unrelated at first glance, but they boil down to one sentence: cell-format standardization is driving capital equipment investment, and the faster that investment accelerates, the more the scope of the patents underpinning it gets tested.
Over the past two years, the industry has watched the large-format cylindrical cell race that began with the 4680 (Tesla) branch out into the 46-series (4695, 46120, and others). The problem is that this branching is happening as each cell maker adopts a slightly different tabless structure. The standard is converging on one number, but the way that standard is implemented — and the patents protecting that implementation — are not converging at all. This tension surfaced for the first time this week through the formal procedure of a trade-commission investigation. This piece answers the question: “Why is 46mm cylindrical-cell standardization spilling into patent risk right now, and what should planning and IP staff who need to weigh equipment investment alongside IP portfolios check first?”
② Basic Principle
To understand the tabless structure, start with the structural weakness of the conventional cylindrical cell. A typical cylindrical cell welds one or a small number of narrow metal tabs to each end of an electrode wound into a jelly-roll, to collect current. The analogy is a multi-story building with only one or two emergency exits. Under normal conditions this is fine, but when a large crowd (current) has to evacuate all at once (high power output, fast charging), congestion and heat build up at that narrow doorway. Because current has to travel a long distance along the electrode before reaching the tab, internal resistance rises, and that resistance turns into heat.
Source: concept diagram reconstructed by the editorial team from the explanation in section 2
The tabless design replaces this emergency exit with “a continuous emergency staircase wrapping the entire perimeter of the building.” It leaves the uncoated metal-foil edge at the top and bottom of the electrode foil, cuts that edge into many closely spaced pieces (flags), folds and overlaps them, and welds the whole thing directly onto the current-collector plates (can caps) at the top and bottom of the cell. As a result, the entire circumference of the electrode becomes a current-carrying path simultaneously, shortening the current’s travel distance and reducing internal resistance and heat. This tabless structure is what has allowed the 46-series to establish itself as a cell that is “bigger, yet still capable of fast charging.”
③ Comparison: Specs by Cylindrical Cell Format
| Format | Diameter×Height (mm) | Main Adopters | Tab Structure | Representative Application |
|---|---|---|---|---|
| 2170 | 21×70 | Panasonic, LG Energy Solution | Conventional tab structure (including improved variants) | Tesla Model 3/Y (older), ESS |
| 4680 | 46×80 | Tesla, Panasonic, LG Energy Solution | Tabless (continuous flag welding) | Tesla Cybertruck, Model Y (new) |
| 4695 | 46×95 | Samsung SDI | Tabless | Power tools, micromobility |
| 46120 | 46×120 | AESC (Envision) | Tabless | BMW iX5 (New Class, expected launch late 2026 to early 2027) |
Source: compiled by the editorial team from the company announcements and reports cited in the article
What this table shows: the 46mm diameter has effectively hardened into a de facto industry-wide specification, but height (80/95/120mm) and the way tabless is implemented still diverge by company — AESC’s own claim of roughly 30% more usable energy per cell versus the prior generation illustrates the reason for this divergence. It is precisely at this point — where the spec converges while the design details diverge — that patent disputes arise. (Note: AESC has not officially disclosed the exact Wh/kg-class energy density of the 46120 cell, so this figure is separated out here as an item requiring confirmation.)
④ Patent Perspective
The heaviest piece of news this week is Investigation No. 337-TA-1518, which the U.S. International Trade Commission (ITC) voted to institute on August 20 and published in the Federal Register on August 24. The case originated from a patent-infringement complaint filed on July 21 and supplemented on August 5 by LG Energy Solution (Korea) and LG Energy Solution Arizona. The complaint asserts five U.S. patents, of which four are reported to relate to cylindrical batteries (including tabless cell design) and one to a separator. The respondents are cell maker EVE Energy (Huizhou, China) and its U.S. subsidiaries, along with downstream importers including Robert Bosch, Koki Holdings (parent of HiKOKI/Metabo HPT), and Chervon (parent of EGO Power+/SKIL/Flex) — ten companies in total. An interesting point is that no automaker is named as a respondent in this investigation at all — the accused products are concentrated in power-tool battery packs.
From a claim-scope standpoint, what this case signals is clear. The tabless structure itself already sits within foundational patent territory that Tesla staked out first (U.S. Patent US11749842B2, “Cell with a tabless electrode,” assigned to Tesla, filed November 4, 2019, granted September 5, 2023, currently active), but LG Energy Solution’s complaint here is based separately on its own 46-series patent portfolio. In other words, rights to the “concept” of tabless and rights to the specific “design” that implements that concept are held by different parties, meaning a single cell product could potentially carry infringement exposure under both layers of rights at once. (Note: the registration numbers of the five specific patents LG Energy Solution asserted in this complaint are not confirmed in public press releases, and are flagged here as a separate item requiring confirmation.)
From a design-around standpoint, this investigation points to two practical scenarios. First, a “structural-variant” design-around that keeps the tabless structure but designs the flag-cutting/folding pattern or current-collector welding method differently from the claim elements. Second, a workaround that abandons full tabless in favor of a “multi-tab” structure — increasing the number of tabs to lower resistance while stepping outside whatever claim requirement calls for “a continuous flag folded to form a concentric structure.” That said, neither scenario has yet been ruled on by a court or the Commission, and both the infringement question and the effectiveness of any design-around remain, for now, strictly in the realm of possibility.
⑤ Limitations and Outlook
The optimistic scenario runs like this: the 46-series settles in as a common industry specification, the equipment and materials supply chain benefits from standardization, patent disputes get resolved through licensing negotiations, and the market keeps expanding. In fact, LG Energy Solution has framed this complaint as part of “building a domestic industry through the Queen Creek, Arizona plant,” and along with the continuing flow of automation-equipment orders such as JS Robotics’ contract, this can be read as a signal of market expansion.
Even so, a counter-scenario needs to be kept in reserve. A Section 337 investigation typically takes 12 to 18 months, and even if the Commission finds a violation and issues an exclusion order, that order only takes effect after a 60-day presidential review period — meaning the immediate market impact is limited. But conversely, this also means that for 12 months or more, later-entering cell makers or automakers considering adopting the 46-series face persistent uncertainty over whether the tabless design they are about to adopt could end up subject to an import restriction depending on how this litigation is resolved.
As a strategic alternative, a company evaluating 46-series adoption could explicitly build into its FTO (freedom-to-operate) review, starting at the procurement-contract stage, an assessment of which patent family — the Tesla-line foundational patent or the LG Energy Solution-line applied patent — the tab structure of the cells it intends to source is closer to.
A practical action for readers (planning and IP staff): if you are evaluating the introduction of 46-series cells or related automation equipment, consider adding to this quarter’s procurement checklist a written-confirmation step with your supplier covering the specific patent-license status of the tab structure — namely, whether it is licensed under the Tesla-line patent, and whether a cross-license exists with LG Energy Solution.