Slitting is more than narrowing a roll. Tooling, tension, coating edges, and extraction jointly determine whether burrs, chipping, dust, and metal particles reach the cell.
How the edge is formed
Mechanical and laser cutting leave different defect families
Mechanical slitting forms shear and fracture zones through blade overlap and lateral clearance. Dull tools, excessive overlap, wrong clearance, or tension vibration cause foil burrs, bent edges, coating chipping, and dust. It avoids a heat-affected zone but needs maintenance by mileage and defect trend.
Laser cutting is flexible and contact-free, but mismatched power, pulse, focus, or speed can create beads, spatter, heat-affected zones, or coating ablation. Parameters must be qualified separately for aluminum, copper, coating material, and thickness.
| Route | Typical defects | Key checks |
|---|---|---|
| Mechanical slitting | Burr, curl, shedding, tool marks | Blade, overlap, clearance, tension, extraction |
| Laser cutting | Bead, HAZ, spatter, edge ablation | Wavelength, focus, power, frequency, speed, fumes |
First-piece and patrol inspection
Inspect both edge faces, roll positions, and tool-life stages
One microscope image can miss intermittent burrs. First-piece inspection should cover both edges, both faces, and multiple consecutive fields. Recheck at roll changes, splices, tool-life milestones, and alarms, binding width, straightness, and edge profile to roll, length, and knife position.
Besides microscopy, white collection plates, tape, or extraction residue show particle trends; metallic glints can be confirmed by microscopy or elemental analysis. A sudden rise in particles should stop the line for tooling and edge localization rather than relying on later screening.
- —Track left and right tool positions separately
- —Fix magnification and lighting
- —Locate anomalies by running length
Why particles matter
Metal particles can become soft-short sources after assembly pressure and cycling
Copper, aluminum, and other metallic particles from cutting or joining can lodge at the electrode-separator interface, damage the separator under assembly pressure, formation, or cycling expansion, and create a local conductive path. Risk depends on size, shape, position, and load, not total particle count alone.
Edge burrs, metallic particles, and extensive shedding therefore require quarantine and traceability. Downstream OCV-drop or self-discharge screening can catch some faults but does not replace source control, and longer aging increases work in process and floor-space cost.
When safety-relevant particles are found, affected roll sections cannot be released based on average width/loading or later sample checks.
Tool life and closure
Change tooling by defect trend, not calendar days alone
Tool-life records should include chemistry, coating thickness, foil, speed, cumulative length, sharpening count, and edge-defect trend. Material hardness and coating toughness change wear rate, so one calendar interval cannot serve every product.
Closure should identify tool, edge side, starting meter, affected electrode rolls and cell lots, cleaning/tool replacement, and recovery first-piece. That detail allows formation or field faults to be traced to a specific roll section.
| Trigger | Floor action | Recovery condition |
|---|---|---|
| Rising burr/dust trend | Confirm at lower speed and inspect blade, overlap, and extraction | First-piece microscopy and particle checks pass after service |
| Periodic edge curl | Check tension, arbor runout, and incoming roll shape | Consecutive steady sections pass dimensions and roll shape |
| Metallic glints or abnormal particles | Stop, quarantine, and identify composition/source | Source removed, line cleared, and verification passed |
Bibliography
References
- 01Characterization and process optimization of remote laser cutting of current collectors for battery electrode production
- 02Electrochemical Mechanism and Defect Detection for Lithium-Ion Cell Containing Copper Particles
- 03Voltage drop screening for defective cells during the battery formation process
- 04In-line quality control for electrode manufacturing: Advanced sensing and defect detection in battery production
Updated: 2026-08-26