Overlay, one side (Cu/Al)
Copper covers one full face. Used for transition tabs and connectors that join copper on one side and aluminium on the other.
Bimetal strip and coil
Copper Clad Aluminium Strip
Copper clad aluminium strip is thin roll-bonded Cu/Al laminate supplied in coils or slit widths for high-speed stamping and welding. It gives stamped parts a copper face, stripe or edge exactly where they make electrical contact, and aluminium everywhere else for low weight and cost. Metline supplies overlay, inlay and edge-lay strip, typically 10 – 30 % copper, to battery, connector and electronics manufacturers worldwide.
- Types
- Overlay, inlay, edge-lay
- Copper
- About 10 – 30 % of thickness
- Thickness
- About 0.1 – 3 mm
- Supply
- Coils, slit strip, cut lengths
Why use clad strip instead of plate or solid copper
Strip is the form of copper clad aluminium designed for volume manufacturing. Coils feed straight into progressive dies, laser-welding lines and automated assembly, so a manufacturer can produce millions of bimetal tabs, terminals and connectors without handling individual blanks. Because the bond is made in the rolling mill, every part arrives with a permanent copper-aluminium joint already built in.
The economic case rests on putting copper only where it is needed. A battery connector may need copper only at the weld zone that meets a copper terminal; a lead frame may need copper only on its contact fingers. Inlay and edge-lay strip place a narrow copper stripe exactly there, so the copper content of the part can drop to a small fraction of a solid copper design.
Overlay, inlay and edge-lay strip
Overlay, two sides (Cu/Al/Cu)
Copper on both faces with an aluminium core, for conductors that must solder or contact on both sides and stay flat.
Inlay
One or more copper stripes rolled into the aluminium surface so the strip stays flat and uniform in thickness. Copper appears only where the drawing calls for it.
Edge-lay
Copper and aluminium joined edge to edge across the width, so one end of a stamped tab is copper and the other aluminium.
Full clad (wrapped)
Copper on both faces and edges, used where no aluminium may be exposed on the formed part.
Reverse clad (Al/Cu/Al)
Copper core with aluminium faces, for parts welded to aluminium on both sides that need copper conductivity inside.
Typical specification and weights
Typical supply range
- Materials
- C11000 or C10200 copper with 1060 or 1070 aluminium; other pairs by agreement
- Copper fraction
- About 10 – 30 % of thickness for overlay; stripe width and depth to drawing for inlay
- Thickness
- About 0.1 – 3 mm (thicker laminates are supplied as plate)
- Width
- Slit widths from a few millimetres up to several hundred millimetres
- Temper
- Annealed, half-hard or hard to suit forming
- Supply form
- Coils on cores, traverse-wound spools for narrow strip, or cut lengths
- Surface
- Bright, passivated, tin- or nickel-plated copper face
Confirm your width, thickness and ratio at enquiry; feasibility depends on structure.
The table gives weight per metre for some common sizes, calculated from the laminate density, so you can estimate coil lengths and part weights.
| Thickness × width (mm) | Area (mm²) | 15 % Cu (g/m) | 30 % Cu (g/m) | Solid copper (g/m) |
|---|---|---|---|---|
| 0.2 × 20 | 4 | 14.5 | 18.2 | 35.6 |
| 0.3 × 30 | 9 | 32.7 | 41.0 | 80.0 |
| 0.5 × 25 | 12.5 | 45.4 | 57.0 | 111.1 |
| 0.5 × 50 | 25 | 90.7 | 113.9 | 222.2 |
| 1 × 30 | 30 | 108.9 | 136.7 | 266.7 |
| 1 × 60 | 60 | 217.7 | 273.4 | 533.4 |
| 1.5 × 50 | 75 | 272.1 | 341.8 | 666.8 |
| 2 × 80 | 160 | 580.6 | 729.1 | 1422.4 |
| 3 × 100 | 300 | 1088.5 | 1367.1 | 2667.0 |
Calculated from rule-of-mixtures densities (3.63 and 4.56 g/cm³) and 8.89 g/cm³ for copper.
Applications of copper clad aluminium strip
| Application | Typical structure | Why clad strip |
|---|---|---|
| Battery cell connectors and module busbars | Cu/Al overlay or edge-lay | Laser or ultrasonic welds copper to copper and aluminium to aluminium, avoiding direct dissimilar welds |
| Battery terminal tabs | Cu/Al or Cu/Al/Cu | Copper surface for nickel plating and welding with an aluminium body |
| Stamped terminals and connectors | Inlay | Copper only at contact points; lighter and cheaper than solid copper |
| Heat spreaders for LED and power electronics | Cu/Al or Cu/Al/Cu | Copper face spreads heat under the device; aluminium sheds it at low weight |
| Cable shielding and EMI parts | Thin overlay | Copper conductivity with aluminium weight |
| Transition washers and shims | Cu/Al overlay | Prevent galvanic corrosion between copper and aluminium conductors |
For EV and stationary battery packs in particular, where cell terminals and module busbars may be in different metals, clad strip has become a standard way to make welded joints reliable. See also our battery bus bar and power battery aluminium pages.
Slitting, stamping and welding clad strip
- Slitting: sharp knives and correct clearance give clean edges; edge burr should be specified for stamping.
- Stamping and forming: annealed strip forms well; keep bend radii generous on the copper side so the thin copper layer does not thin or crack.
- Laser and ultrasonic welding: weld copper to copper and aluminium to aluminium; keep heat input low so the interface stays below the temperature where brittle intermetallics grow quickly.
- Plating: tin or nickel plating on the copper face improves solderability and weld consistency.
- Storage: keep coils dry and wrapped; copper oxidises and stains in humid air, which affects welding.
Avoid annealing or brazing finished parts. Long exposure above roughly 200 – 250 °C thickens the Al2Cu-type intermetallic layer at the interface and weakens the bond.
Inspection and certificates
Strip is checked for layer ratio on cross-sections taken from the coil ends, peel and bend tests for bond, thickness and width tolerance, camber and flatness, and surface condition. Conductivity is measured on request. Each delivery comes with an EN 10204 3.1 certificate covering these results, plus coil identification so every part can be traced back to its lot.
References and standards
- ASTM B209 – Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
- ASTM B152/B152M – Standard Specification for Copper Sheet, Strip, Plate, and Rolled Bar
- EN 1652 – Copper and copper alloys: plate, sheet, strip and circles for general purposes
- ASM Handbook, Vol. 6 – Welding, Brazing and Soldering (roll bonding)
Copper clad aluminium (aluminum) strip: FAQ
What is inlay copper clad aluminum strip?
Inlay strip has one or more copper stripes rolled into the surface of an aluminium strip, flush with it. Copper is present only where parts need electrical contact or welding, which saves weight and cost.
How thick is the copper layer?
Typically 10 – 30 % of total thickness for overlay strip. On a 0.5 mm strip with 20 % copper, the copper layer is about 0.1 mm thick.
Can clad strip be laser welded?
Yes. Weld the copper face to copper parts and the aluminium face to aluminium parts, with heat input controlled so the bond interface is not overheated.
What is the difference between strip and plate?
Strip is thin laminate (up to about 3 mm) supplied in coils or slit widths for automatic stamping. Plate is thicker and supplied as sheets, blanks or machined parts.
Why is clad strip used in battery packs?
It allows copper and aluminium cell terminals and busbars to be joined by welding same metal to same metal, avoiding brittle direct copper-aluminium welds and galvanic corrosion at the joint.
Need copper clad aluminium strip in coil?
Send the structure, ratio, thickness, width and annual volume. We will reply with feasibility, test plan and pricing.
