① What is in the spotlight
Solid Power (Solid Power Operating Inc)’s U.S. patent application US20260088331A1 claims a frame jig (a process fixture) that lets an isostatic press “press the flat faces while protecting the edges” of an all-solid-state pouch cell. The key is not a new material but controlling, through structure, where the pressure lands. As of late August 2026 the application is under examination (Pending), so its scope of rights is not yet settled.
First, the bibliographic data. The applicant is solid-state battery developer Solid Power, the inventor is David A. Telep, and the application number is US19/341,895. It was filed on September 26, 2025 and published on March 26, 2026, claiming priority to U.S. provisional application 63/699,688 filed on September 26, 2024. According to Google Patents, the only family member visible at publication is this single U.S. application; it has 22 claims in total, of which three (claims 1, 13 and 22) are independent.
The industry context is this. In an all-solid-state battery, ions only pass when solid-electrolyte and electrode particles are tightly in contact, so a manufacturing step that presses and densifies the cell is close to essential. Isostatic presses, which press uniformly from all directions using fluid pressure, and especially warm isostatic presses (WIP) that heat the fluid, are drawing attention. The tension is that if a pouch cell goes in as is, the pressure also bites into its sides and the area around the tabs (electrode terminals). This article answers two questions: what structure did Solid Power use to solve this problem, and how far might its claims reach?
② Basic principle
The structure of this patent is close to a “picture frame.” When a photo (the solid-state cell) is placed in a frame, the rigid border protects the photo’s edges, while a thin, flexible film inside transmits pressure evenly only to the flat face. The specification describes this flexible material as a liquid-impervious film and states that it keeps the pressing fluid from directly contacting the cell layers.
Source: reconstructed by the editorial team from the claims and specification of US20260088331A1
The problem the specification identifies is concrete. When pressed without protection, the edges and sides of the cell stack are susceptible to damage, and the tab and weld areas are also vulnerable to pressure. If layers near the edge are pinched together, two conductive layers may touch and cause a short, and severe bending of the layers may cause deformities such as cracking. In other words, the pressure applied for densification becomes a defect pathway for that very cell.
The frame filters this pressure by “direction.” The specification explains that, through the flexible film, a substantially uniaxial load perpendicular to the cell’s large planar surface is applied. Fluid pressure that came from all sides is, after passing through the frame, converted into force pressing from top and bottom. The process conditions stated in the specification are a pressing force of 20k-60k psi (about 138-414 MPa when converted) on the cell layers and fluid warmed up to 90°C, which it says may be considered a warm isostatic press.
- Rigid outer perimeter: prevents the pressing force on an end of the cell (claim 1).
- Flexible inner material: transmits the pressing force to the cell layers. The polymer limitation is in a dependent claim (claim 12).
- Inset in the second plate: receives the cell and positions it between the two plates (claim 1).
③ Comparison
Placing a conventional isostatic press side by side with the framed process, the difference converges on one thing: controlling the direction of pressure. The table below refines the original comparison table in line with the claim check.
| Item | Conventional isostatic press (no frame) | With the US20260088331A1 frame |
|---|---|---|
| Direction of pressure | Isotropic pressure over the entire cell | Substantially uniaxial load on the flat faces (specification) |
| Protection of cell sides and tabs | No dedicated protection; risk of deformation | Rigid outer frame blocks pressing force on the cell end (claim 1) |
| Layers of different sizes | Process conditions must be tuned per layer | Recessed shelf accommodates a larger layer (claim 4) |
| Electrode tab handling | Separate masking needed to avoid tab damage | Tab recess reserves the tab position in advance (claim 6) |
| Process scope | General-purpose isostatic press | Specialized for pressing all-solid-state pouch cells |
Source: reconstructed by the editorial team from the claims and specification of US20260088331A1
What this table says: Four of the five items correspond to a specific element in the claims or specification. The real value of this application is that it leaves general-purpose equipment unchanged and adds only a consumable jig to cut off damage pathways.
Viewing the claim structure as a table also reveals the layers of the scope of rights. With three independent claims, the application separately targets an apparatus (the frame), a method (the pressing process) and a generalized frame.
| Claim | Type | Key elements (paraphrased) | Scope interpretation |
|---|---|---|---|
| 1 | Independent (apparatus) | First plate with rigid perimeter + flexible interior, second plate with an inset receiving the cell, pressing force on the cell end blocked | Presupposes a “solid-state battery cell” and an “isostatic press” |
| 12 | Dependent | Flexible material is a polymer | Material limitation exists only in dependent claims |
| 13 | Independent (method) | Load cell → mate two plates → press through the flexible material with an isostatic press | Requires rigid perimeter + flexible interior on both plates |
| 14, 21 | Dependent | Use of a WIP device; evacuating air from inside the frame before pressing | Narrows process conditions to support allowability |
| 22 | Independent (apparatus) | An “electrochemical object” placed between two plates and pressed by a press | Object not limited to solid-state battery cells |
Source: reconstructed by the editorial team from the claims of US20260088331A1 on Google Patents
What this table says: Of the 22 claims, the three independent claims are split into apparatus, method and generalized apparatus. Claim 22 in particular broadens the object to an “electrochemical object,” so its scope may reach beyond all-solid-state cells.
④ Patent perspective
Gist of the claims. In substance, claim 1 claims a frame in which “a first plate is mated with a second plate; the first plate consists of a rigid outer perimeter frame and an inner portion covered with a flexible material; the second plate has an inset receiving the cell to place it between the two plates; and while an isostatic press applies a pressing force to the cell layers through the flexible material, the rigid frame prevents the pressing force on an end of the cell.” Read on its own, claim 1 requires the rigid perimeter and flexible interior only on the first plate; giving the second plate the same configuration is a dependent claim (claim 5).
Source: reconstructed by the editorial team from the claims of US20260088331A1 on Google Patents
Claims versus specification. The sentence “the frame may comprise a metal material” appears in the specification, not in the claims. Likewise, “a flexible, liquid-impervious material” is the specification’s description; the wording of claim 1 is simply “a flexible material.” It is therefore more accurate to say that, on the material side, claim 1 is written broadly as “a flexible material,” and the polymer limitation appears only in claims 12 and 20.
Filing history. The sequence is: provisional filing on September 26, 2024; non-provisional filing on September 26, 2025; docketed for examination on October 17, 2025; publication on March 26, 2026. A prior patent addressing a similar problem is Hyundai Motor and Kia’s KR20190056666A (filed November 17, 2017; granted as KR102529492B1 on May 4, 2023; Active). That patent coats the electrode edges with a pressure-plastic polymer, seals the cell in a pouch and presses it to form an insulating layer, solving the same edge-damage-under-pressure problem with a material inside the cell. Solid Power’s application solves the same problem with a jig outside the cell, so the two work at different layers of solution.
Design-around points. Based on the wording of claim 1, there is a risk of infringement when all of the following elements are met: first, a first plate divided into a rigid perimeter and a flexible interior; second, a second plate with an inset receiving the cell; third, pressing by an isostatic press; and fourth, blocking the pressing force on the cell end. A design that literally lacks one of these may have a possibility of avoidance, but if it produces substantially the same function and effect it may be subject to a doctrine-of-equivalents analysis.
- Design-around scenario A (from the original): achieve the same effect with a hardness gradient in a single material instead of physically separating border and interior. Whether this escapes the claimed “two distinct regions” requires a separate infringement opinion.
- Design-around scenario B: placing the whole cell in a rigid die and using a uniaxial press may lack the “isostatic press” element. However, claim 22 is written as isostatic pressurizing “via a press,” leaving room for interpretation.
- Counterargument: measured against the broad functional language of the specification, neither scenario is a confirmed design-around. A conclusion can only be drawn through FTO (freedom-to-operate, infringement) review after the allowed claims are known.
⑤ Limits and outlook
The optimistic outlook is that this frame structure becomes the standard jig for mass production of all-solid-state pouch cells, giving Solid Power licensing leverage on both the equipment and process sides. There is, however, a counter-scenario: isostatic-press equipment makers or cell makers running their own pressing processes may develop alternative jigs that achieve a similar effect without a frame, pre-emptively designing around it before grant. In that case, the application’s real value depends on how much of broadly written claims such as claim 22 survives examination.
The strategic alternative is intervention at the examination stage. The United States has a third-party preissuance submission system; according to USPTO guidance, prior art may be submitted before the later of the date six months after publication or the date of a first Office action rejecting any claims (or before a notice of allowance, if earlier). Since this application was published on March 26, 2026, the six-months-after-publication date is September 26, 2026. Companies holding prior art such as edge-protecting pressing jigs or edge-insulation technology can consider whether to submit within this window.
Here is this article’s own interpretation. The center of gravity of this application is likely to lie in claim 22 rather than claim 1. Claim 1 presupposes a solid-state battery cell and an isostatic press, but claim 22 broadens the object to an “electrochemical object.” If this broad claim is granted without amendment, cell-pressing processes beyond all-solid-state could also become subject to FTO review.
Practical action: IP staff reviewing pressing jigs for all-solid-state pouch cells should build a table mapping their design against the four elements of claim 1 (divided first plate, inset second plate, isostatic pressing, blocking force on the cell end) and against the wording of claim 22, and decide on a third-party preissuance submission with the September 26, 2026 reference date in mind.
Items requiring verification
- Whether and when a first Office action has issued on US20260088331A1 (affects the submission deadline)
- Specific examples of “cell makers already running their own WIP process” mentioned in the original (the original’s reference to a specific company could not be confirmed from a primary source and was removed from the body)
- Whether continuation or foreign counterpart (PCT, etc.) applications exist
Sources
- Google Patents, US20260088331A1 – Flexible frame for use in applying high pressure in the manufacture of a solid-state battery cell (Solid Power Operating Inc)
- Google Patents, KR20190056666A / KR102529492B1 – Method for manufacturing an all-solid battery and all-solid battery manufactured thereby (Hyundai Motor Company, Kia)
- USPTO, Third-party preissuance submissions (35 U.S.C. 122(e)) guidance