Read claim 1 of US20260204733A1 and the first thing worth noticing is what it does not say. The application, titled BATTERY AND METHOD FOR MANUFACTURING BATTERY and assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA, published on July 16, 2026 with six named inventors — Tetsuya Waseda, Hideyuki Tokioka, Yuki Sato, Takuya Matsuyama, Kenichi Kakishita and Takuya Kimura. It is an A1 publication: a pending application, published but not granted, and every statement below describes what is claimed, not what has been allowed.

The structure claim 1 recites is a mirrored stack. At the center sits a first current collector layer. On it, the claim requires "a pair of first electrode layers disposed on one surface and the other surface of the first current collector layer" — a double-sided limitation, present in the independent claim, that matters later. Outward from each of those first electrode layers, in order: a solid electrolyte layer, a second electrode layer, and a second current collector layer, each recited as a pair. The cell is symmetric about its center collector, which is the geometry of a bipolar-style stacked assembly.

The point of novelty, though, sits inside the second electrode layer rather than in the stacking order. That layer is not a homogeneous mix. It contains both active material and solid electrolyte, and the ratio between them is deliberately non-uniform across the layer's thickness — electrolyte-rich where it meets the separator, electrolyte-poor where it meets the outer collector.

wherein the second electrode layers each contain an electrode active material and a solid electrolyte, and a content ratio of the solid electrolyte is higher on the solid electrolyte layer side than on the second current collector layer side in a thickness direction.— BATTERY AND METHOD FOR MANUFACTURING BATTERY, US20260204733A1

That is the whole of the grading limitation, and it is stated in structural terms only: a content ratio, a direction, two reference surfaces. Nowhere in claim 1 do the words cathode or anode appear. The layers are "first" and "second" throughout, and the gradient is defined relative to the parts it touches — the solid electrolyte layer on one side, the second current collector layer on the other. A reader who arrives expecting the independent claim to name an electrode chemistry will not find one there.

Where the electrode roles actually arrive

The assignment comes one level down. Claim 3, which depends from claim 1, states that "the first current collector layer is a cathode current collector layer" and that "the second electrode layers are anode layers", with the second current collectors as anode current collectors. So the graded layer — the second electrode layer, the one carrying the electrolyte gradient — is the anode under the claim 3 reading. It is worth being precise about that dependency: the graded-anode construction is a claim 3 construction. Claim 1 itself is agnostic as to which half of the cell is which, and describing claim 1 as covering a graded anode would misstate what the independent claim recites.

Claim 4 then depends from claim 3 and specifies that "the anode layers each contain silicon as the electrode active material". Silicon therefore sits two levels below the independent claim, in the chain 1 → 3 → 4, and reaching it requires accepting both the electrode-role assignment of claim 3 and the material limitation of claim 4. This is an ordinary drafting pattern — structure first, roles second, chemistry third — but it changes how the application should be summarized. The silicon is a specified embodiment, not an independent-claim requirement.

The dependent set also supplies a construction route. Claim 2 recites that at least one second electrode layer includes "a plurality of partial second electrode layers laminated in the thickness direction", with electrolyte content higher in the sub-layer nearer the solid electrolyte layer than in the sub-layer nearer the collector. In other words, the gradient need not be continuous; it can be approximated as a stack of discrete slabs of differing composition. Claim 5, the method claim, follows that logic directly: it recites pressing the first-electrode laminate, then "disposing, by transfer using a transfer material including a substrate and a solid electrolyte layer containing a solid electrolyte", then transferring a first partial second electrode layer, then a second partial second electrode layer of lower electrolyte content. The gradient is built by sequential transfer, one composition at a time.

Classification and landscape position

The classification set reads consistently with that reading. The record carries H01M 50/461 and H01M 50/449 — separator and separator-material classes — alongside H01M 10/0525 for lithium secondary cells with insertion electrodes and H01M 10/0585 for stacked-electrode constructions, which is where the mirrored double-sided geometry lands. On the electrode side, H01M 4/386 covers silicon-containing active materials, H01M 4/366 covers coated or multi-component electrode actives, H01M 4/667 covers current collector construction, and H01M 2004/027 is an indexing code for the cathode/anode designation itself. The combination places the application in the stacked lithium solid-state cell space rather than in a pure materials class, with the silicon designation appearing in the classification even though it enters the claims only at claim 4.

One divergence deserves flagging for anyone working from the front page. The abstract describes "first electrode layers disposed on the first current collector layer" and omits the pairing language entirely. Claim 1 requires the pair, on one surface and the other surface. The double-sided requirement is a claim limitation that the abstract does not carry, so the abstract functions here as background description of the disclosure and not as a statement of what is claimed. The same caution applies to the abstract's rendering of the gradient, which drops claim 1's "in a thickness direction" qualifier.

The application arrived inside a dense same-day cluster from the assignee. The July 16 publications include US20260204709A1 (SECONDARY BATTERY), US20260204753A1 (BATTERY PACK AND BATTERY PACK MANUFACTURING METHOD), US20260204665A1 (POWER STORAGE DEVICE), US20260204617A1 (METHOD OF MANUFACTURING POWER STORAGE DEVICE AND POWER STORAGE DEVICE), US20260204670A1 (METHOD FOR DETECTING ABNORMALITY IN STORAGE BATTERY) and US20260204594A1 (MEMBRANE ELECTRODE ASSEMBLY), with vehicle-level filings such as US20260206044A1 (VEHICLE) in the same window. Cell construction, pack assembly and battery diagnostics all appear together. What US20260204733A1 adds to that group is a specific, claimed answer to a specific interface problem: rather than treating the electrode as one uniform composite, it claims varying the electrolyte fraction across its thickness, and — at claim 3 and claim 4 — applies that gradient to a silicon-bearing anode. Prosecution will determine what survives; as published, that is the claim set on file.