Overview

Current collector etching cuts tabs, slots, coating windows and perforation patterns into battery electrode foil by photochemical machining, working on metal thin enough that mechanical blanking struggles: 8–30 µm aluminum for the cathode, 6–20 µm copper for the anode, and 15–50 µm nickel for supercapacitors and specialty cells. The foil is laminated to a temporary carrier, patterned on both faces and etched through, then released, so the finished part keeps its flatness and carries no shear burr along the cut edge. Alloys in routine use are 1060, 1070 and 1235 aluminum, C1100 copper and nickel 201.

The reason to etch rather than stamp or laser-cut is the edge. A die leaves a roll-over and a fracture zone on a 10 µm foil, and laser cutting leaves a recast bead and a heat-affected rim; both create burrs and hardened spikes that can pierce a 12 µm separator and cause self-discharge or an internal short. Etched edges are smooth and burr-free to within a few micrometres, and the tab comes out flat, which matters for ultrasonic welding because a tab that is bowed or work-hardened does not couple reliably to the busbar. A single current collector etching step also defines the coating boundary, the slot array and the fuse or vent window in one pass, replacing trimming and notching without touching the temper of the foil.

Parameter Window

• Available Materials: 1060/1070/1235 aluminum foil, C1100 copper foil, nickel 201 foil
• Material Thickness Range: 6–50 µm; carrier-supported handling down to 6 µm
• Tolerance: ±0.03 mm on tab profile, ±0.02 mm on slot and window position, edge burr ≤3 µm
• Minimum Feature: 0.08 mm slot width at 12 µm foil, 0.15 mm web between adjacent windows
• Surface Options: chromium-free passivation, anti-oxidation coating, primer-compatible finish, Ra 0.2–0.6 µm, no oil residue
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Tab and Pattern Review — Check tab width, root radius, slot layout and coating window against the cell design, and confirm which cuts are through-cuts.
2. Foil and Carrier Selection — Match alloy and temper to the electrode, then choose a carrier film and frame that will survive the etchant without stretching the foil.
3. Cleaning & Lamination — Remove rolling oil and laminate resist on both faces under low tension, so a 10 µm foil is not wrinkled before it is patterned.
4. Exposure — Expose through film registered to the tab datum; both faces are exposed so the through-cut has a symmetric wall.
5. Development — Open the tab outline, slots and windows, and inspect for resist residue at the tab root where undercut would start.
6. Through Etching — Etch to breakthrough in a conveyor system with the foil supported, controlling undercut to roughly one foil thickness.
7. Stripping & Passivation — Strip resist, neutralise, passivate chromium-free and rinse in de-ionised water to a defined conductivity.
8. Burr & Flatness Inspection — Measure burr height under a profile projector or SEM, check tab flatness and dimensional accuracy, then interleave and pack.

Core Advantages

1. Burr-free edges on micron foil: Etched edges stay within 3 µm of burr, removing the spikes that puncture separators and drive self-discharge.
2. Flat, weldable tabs: No shear or laser hardening, so the tab stays annealed and flat and couples consistently in ultrasonic welding.
3. No die for thin stock: A 10 µm foil distorts in a stamping die; etching patterns it without clamping force, and a design change is only a new film.
4. Patterns in one pass: Tab outline, coating window, slot array and fuse window are etched together, so no secondary trimming step touches the foil.
5. Wrinkle-free handling: Carrier-supported processing keeps the foil flat through lamination, etching and rinsing, which protects coating adhesion later.
6. Clean, coating-ready surface: Chromium-free passivation and DI rinse leave no oil or etchant residue to blister the electrode slurry.

Typical Applications

• Cathode current collectors: Aluminum tabs and coating windows on 12–20 µm foil for pouch and prismatic lithium-ion cells.
• Anode current collectors: Copper foil collectors with etched tabs for graphite and silicon-dominant anodes.
• Tab-less cell designs: Multi-tab and continuous-tab patterns that shorten the current path and reduce internal resistance.
• Perforated collectors: Aperture arrays in copper or nickel foil that improve wetting and adhesion for thick or silicon anodes.
• Supercapacitor collectors: Nickel and aluminum foil collectors with etched patterns for high-power cells.
• Solid-state and thin-film cells: Fine collector patterns on thin foil where the stack is laminated under pressure.

Design Notes & Process Considerations

1. Burr must be specified with a method: State burr height and the measurement technique; "no burr" is not inspectable on a 10 µm foil, whereas 3 µm maximum is.
2. Tab root radius: Give at least 0.3 mm radius at the tab-to-body transition; a sharp internal corner concentrates stress and cracks during winding or stacking.
3. Undercut on thin foil: Through-etching widens a slot by about one foil thickness per side, so a 0.08 mm slot needs artwork compensation.
4. Coating window tolerance: The etched boundary sets the coated area, so hold position to 0.02 mm if the cell's capacity balance depends on coat weight.
5. Handling and flatness: Specify carrier type, interleaving and allowable wrinkle height; a crease in 10 µm foil cannot be flattened afterwards.
6. Residue and conductivity: Set a rinse water conductivity limit and a particle requirement, because ionic residue on a collector accelerates calendar fade.