A modern EV battery pack uses aluminium at every level, from 10–20 µm cathode foil inside each cell to 6xxx extrusions in the pack frame. Each part needs a different alloy, temper and gauge. This guide maps the main battery components to the aluminium grades used for them, explains why, and lists what to specify when you buy the material from Metline.
Aluminium does four jobs in a traction battery: it carries current, moves heat, contains the cell chemistry and holds the pack together. It does all four at about one third of the density of steel or copper, which matters in a component that can weigh several hundred kilograms.
At the cathode, aluminium foil is the only practical current collector, because it is stable at the high positive electrode potential where copper would corrode. In prismatic and cylindrical cells, deep-drawn aluminium cans are lighter than nickel-plated steel and easy to laser weld. Across the module, aluminium busbars and brazed cold plates carry current and heat. At pack level, extruded 6xxx frames and 5xxx or 6xxx sheet form the tray, crash structure and lid.
The catch is that each of these parts has a different priority. Foil needs purity and pinhole-free rolling, cans need deep drawability and weld quality, cold plates need a brazing clad layer, and tray members need strength and crash energy absorption. Choosing the wrong grade for a part is the most common cause of forming cracks, weld porosity or failed corrosion tests.
| Component | Typical alloys | Temper | Typical gauge / form | Key requirement |
|---|---|---|---|---|
| Cathode current collector | 1070, 1060, 1100, 1235 | H18 | Foil about 10 – 20 µm | Purity, pinhole control, high strength for coating lines |
| Pouch-cell laminate film | 8021, 8079 | O | Foil in laminate, about 20 – 100 µm | Deep-draw formability, barrier against moisture |
| Prismatic cell can (shell) | 3003, 3005, 1050 | O, H12, H14 | Strip 0.6 – 3 mm, deep drawn | Drawability, uniform wall, laser-weld quality |
| Cell cover plate | 3003, 1060, 5182 | O, H14 | Sheet 1 – 2 mm | Flatness, weldability to can, vent integration |
| Pouch-cell tabs, flexible links | 1060, 1070 | O | Foil or strip 0.1 – 0.3 mm | Conductivity and flexibility |
| Module busbars | 1060, 1070, 6101, 3003 | O, H14, T6 | Strip, flat bar, laminated stack | Conductivity, weldability to cell terminals |
| Cold plates, liquid cooling | 3003 / 4343 or 4045 clad, 3003 mod | O, H14, H24 | Brazing sheet 1 – 3 mm, extruded multiport tube | Brazing response, leak-tightness, corrosion resistance |
| Module side plates, partitions | 5083, 5052, 6061 | O, H32, T6 | Sheet 1 – 3 mm | Strength, insulation coating |
| Pack tray frame and cross members | 6061, 6005A, 6082, 6063 | T6 | Extruded hollow profiles | Strength, crash energy, weldability |
| Tray floor, lid | 5754, 5083, 6061 | O, H22, T4/T6 | Sheet 1 – 4 mm, stamped | Formability, stone-chip and fire protection |
Gauges are typical ranges found across current cell and pack designs. Each OEM or cell maker sets its own specification.
Rolled from 1xxx alloys to H18 for tensile strength on high-speed coating lines. Battery foil is cleaner and tighter in thickness than packaging foil, with strict limits on pinholes, oil residue and surface wettability. Carbon-coated foil improves adhesion and lowers contact resistance.
8021 and 8079 in the O temper are laminated between nylon and polypropylene layers. The iron-rich 8xxx alloys give fine grains and the deep-draw ductility needed to form the cell pocket without cracking.
3003 is the most common shell material: manganese gives more strength than 1xxx while keeping excellent drawability. 3005 adds magnesium for a little more strength; 1050 is used where conductivity or very deep draws matter more.
Flat 3003 or 1xxx sheet that carries the terminals and safety vent, laser welded to the can. Flatness and clean, oxide-controlled surfaces are critical for a sound weld.
Soft 1060 or 1070 strip connects pouch-cell electrodes and flexes to absorb movement between cells. Surface cleanliness affects ultrasonic and laser weld strength.
Most cylindrical cells still use nickel-plated steel cans, but some designs use aluminium cans and housings, typically from 3xxx alloys.
For prismatic cans, see our dedicated 1050, 3003 and 3005 battery shell guide, which covers chemistry, tolerances and laser-weld requirements in detail.
Inside a module, busbars link cell terminals in series and parallel. Aluminium busbars are attractive because the cell terminal itself is usually aluminium on the positive side, so an aluminium busbar avoids a dissimilar-metal joint there. 1060 and 1070 give the highest conductivity (about 61–62 % IACS); 6101-T6 adds strength for longer spans. Laminated and insulated busbars combine several conductor layers with insulation films.
Thermal management is the second big aluminium user. Liquid cold plates are usually made from brazing sheet: a 3003 or modified 3003 core clad on one or both sides with a 4343 or 4045 Al-Si filler layer that melts in the brazing furnace and joins stamped channels into a leak-tight plate. Extruded multiport tubes and harp-type plates do the same job in other designs. The choice of core alloy affects post-braze strength and corrosion resistance in water-glycol coolant.
The battery tray (or enclosure) protects the cells from crash loads, road debris, water and fire, and in many vehicles also stiffens the floor. The common construction is a frame of 6xxx hollow extrusions, cross members and a sheet or extruded floor, joined by friction stir welding, MIG welding, adhesive bonding and self-piercing rivets.
| Tray part | Usual material | Why |
|---|---|---|
| Side sills and frame | 6061-T6, 6082-T6, 6005A-T6 extrusions | High strength and crash energy absorption in multi-cell hollow sections |
| Cross members | 6063-T6, 6005A-T6 extrusions | Good extrudability for complex shapes at lower cost |
| Floor plate | Friction-stir-welded 6xxx extrusions or 5xxx sheet | Flatness, stone-chip protection, integration of cooling channels |
| Lid | 5xxx or 6xxx sheet, sometimes with fire-protection layers | Light, formable, keeps out water and dust |
| Brackets and mounts | 6061-T6 plate or extrusion, castings | Machinable, strong attachment points |
Our EV battery tray and enclosure guide covers tray design, joining methods and alloy selection in more depth.
Because battery suppliers qualify materials carefully, plan for sample coils and a trial run on your own line. Lot-to-lot consistency matters as much as meeting the specification once.
Aluminium forms a stable passive layer at the high potential of the positive electrode, so it does not corrode there. At the low potential of the negative electrode, aluminium would alloy with lithium, so copper foil is used on the anode side.
3003 in the O, H12 or H14 temper is the most common, because it combines good deep drawability with more strength than pure aluminium. 3005 and 1050 are also used depending on the design.
Usually brazing sheet: a 3003 or modified 3003 core clad with a 4343 or 4045 aluminium-silicon filler, stamped and furnace brazed into a leak-tight plate. Extruded multiport tubes are an alternative.
Frames and cross members are typically 6061, 6082, 6005A or 6063 extrusions in T6, with 5xxx or 6xxx sheet for floors and lids.
Metline supplies aluminium foil, strip, sheet, brazing sheet, busbar and extrusions in the grades listed, cut or slit to size, with mill certificates. We supply the aluminium material; cell, module and pack manufacturing is done by our customers.
Tell us the component, grade, gauge and volume. Our team will match material and reply with certification and a delivered price.
