A solid-state pilot line is a hybrid equipment configuration that partially abandons the continuous-transfer premise of existing R2R lines. Once acceptance (검수) has been confirmed, equipment specifications shift from negotiable to fixed values. What domestic equipment makers need to review now is not the introduction of a new process, but the redesign of the load path.
1. News Facts
- Chinese equipment maker Lyric Robot (利元亨) won an order for a solid-state pilot line from a top-tier customer and passed acceptance.
- The Institute of Physics, Chinese Academy of Sciences is operating a pilot line targeting 0.2 GWh of cells in Suzhou, integrating five processes: electrode integration, ion-conductive membrane, pre-lithiation, thermal lamination, and press stacking.
- Industry consensus favors oxide-based materials for early adoption. Sulfide-based mass production is projected for 2028–2030, with cell makers targeting mass production in 2027–2028.
2. Equipment Perspective: What Gets Replaced First
The conventional wisdom on the shop floor is that the solid-state transition changes the coater first. Reading the five integrated processes as they stand, the conclusion is the opposite. Coating remains, while the calender and winder are replaced first — because the press stack absorbs the calender’s compaction function, and thermal lamination absorbs the winder’s stacking function.
This substitution shifts the takt-time bottleneck. The bottleneck variable moves from transfer speed to press dwell time. When a batch process is inserted into a continuous line, buffer-zone length becomes the dominant variable in the layout.
3. Press Stack Load Verification
The load required for flat-plate pressing is the product of surface pressure and effective area.
$$F = p \cdot A, \qquad A = w \times l$$
$F$: required load (kN), $p$: surface pressure (N/mm²), $A$: effective press area (mm²), $w$: electrode width (mm), $l$: electrode length (mm)
With $w = 300$ mm and $l = 100$ mm applied, $A = 30{,}000$ mm².
| Assumed surface pressure p (N/mm²) | Required load F (kN) |
|---|---|
| 50 | 1,500 |
| 100 | 3,000 |
Surface pressure $p$ has no public source and is an assumed value for sensitivity analysis (estimated — varies with electrolyte system and cell configuration, so on-site measurement and reconfirmation is required). Even on the assumed values, the practical implication is that a single press load approaches the MN range.
Safety factor is examined twofold. For static strength, $SF_1 = 2.0$ is applied, securing a frame design load of 6,000 kN at $p = 100$ N/mm². For repeated pressing, a separate fatigue review is performed applying $SF_2$; the frame is not finalized on static review alone.
The load path also differs. In the calender, line load flows through the roll shaft and bearings to the housing. In flat-plate pressing, it flows directly from the platen to four corner columns. When the path changes, reusing the existing frame no longer holds.
4. Spec Comparison Table
| Category | Conventional Li-ion R2R | Solid-State Pilot Line |
|---|---|---|
| Compaction method | Calender roll line load, continuous | Flat-plate/isostatic pressing, batch |
| Stacking method | Winding or Z-stacking | Thermal lamination + press stacking |
| Load path | Roll shaft → bearing → housing | Platen → 4 corner columns → bed |
| Takt-dominant variable | Transfer speed (m/min) | Press dwell time (s/cycle) |
| Alignment tolerance control | Correctable just before stacking | Not correctable after lamination; pre-alignment dominates |
| Pre-treatment process | Not applicable | New pre-lithiation equipment required |
| Environmental conditions | Dry-room dew point control | Dry room + additional requirements by electrolyte system (on-site reconfirmation required) |
5. Shop-notes
A C-frame single-column press can be considered as an alternative mechanism. It has a small footprint and allows front loading. The reason it was not adopted is eccentric loading — the load line of action and the frame centerline are misaligned, causing the press-surface parallelism to collapse in proportion to increasing load. A four-column frame is adopted instead.
A machinability note: platen parallelism should be specified within a grade achievable by grinding. Raising the grade excessively adds a lapping process, which increases both lead time and cost together, ultimately looping back into an ECO.
The opposing view is also noted: if oxide-based materials are adopted first, the required surface pressure may be lower than for sulfide-based systems. However, since compaction remains a batch process either way, the buffer design challenge remains.
6. Design Reflection Checklist
- Has the frame load path been rewritten on a platen–column–bed basis?
- Have static $SF_1$ and fatigue $SF_2$ been verified separately, twofold?
- Have upstream/downstream buffer lengths been calculated based on press dwell time?
- Has the pre-alignment tolerance been finalized before the lamination stage?
- Has the platen parallelism grade been specified within a grindable range?
One-Line Summary
The equipment challenge of the solid-state pilot line is not adding a new process, but redesigning the load path — from line load to flat-plate pressing — and the buffers required by inserting a batch process.
References
- SMM — Solid-state battery supply chain, H1 2026 listed company review
- SMM — Solid-state battery: three fronts