Aluminum Extrusion for New Energy Vehicles: EV Profile Guide

2026-09-30 17:26:38

Electric vehicles are reshaping the extrusion business. A battery electric car carries 200–300 kg of aluminium, a large share of it extruded, and that is why aluminum extrusion for new energy vehicles is the fastest-growing segment for plants in China, Vietnam, Thailand and Malaysia. The profiles are bigger, flatter and held to tighter tolerances than window sections — which changes how you must specify the press, the cooling bed, the haul-off and the saw.

Why EVs are so aluminium-hungry

Batteries are heavy, so every kilogram saved protects driving range. Steel gives way to aluminium across the body and the pack. The main extruded parts are:

• Battery tray / enclosure — the structural floor that holds the cells.

• Crash-management-system (CMS) beams — front and rear energy absorbers.

• Busbars — conductive bars carrying high current between modules.

• Heat-exchange profiles — cooling plates under the cells.

The key profile families

Battery tray and enclosure sections

These are wide, flat, often hollow sections spanning 300–600 mm. They must stay flat within 0.5–1.0 mm/m after cooling or the pack will not seal. A wide, even quench and a long cooling bed are non-negotiable.

Crash-management-system beams

CMS beams are engineered to fold in a crash. They need consistent wall thickness (±0.15 mm) and clean corners, so die design and pull stability matter more than absolute speed.

Busbar and heat-exchange profiles

Busbars value conductivity and surface cleanliness; heat-exchange plates need internal channels that stay open. Both reward precise, low-vibration extrusion.

6xxx vs 7xxx: picking the alloy

For most trays and enclosures, 6xxx series — 6005A, 6061, 6082 — is the workhorse: good extrudability, weldable, strong enough after ageing. 7xxx series (7003, 7020) is called on where peak strength is needed, such as structural rails, but it is harder to extrude and more sensitive to quench. Match the alloy to the station before you commit the tooling.

Why wider presses and longer cooling beds matter

Wide flat sections need containers and flat dies that only larger presses provide. Lines serving NEV plants typically run 2,500–4,000 t presses so a tray can be made in one wide pass rather than welding several parts. The same width makes cooling harder: a long belt-driven cooling bed lets the full length reach ambient without sagging. Short beds force slower press speed and cost you tonnes per shift.

Tolerance and flatness requirements

What the equipment spec should be

The haul-off is where many NEV lines win or lose. A double-pull haul-off machine holds tension through the whole wide section without buckling it, and a precise single-bar saw delivers square, burr-free ends at the cell-module interface. Plan the station sizes together, as shown in our auxiliary equipment station map.

Buying the right line for NEV volumes

If you are entering EV supply, size for the widest tray you will make, not the average. A line that handles a 600 mm section at 12 m/min will also run your 80 mm rails — but the reverse is not true. Pair the press with a high-throughput neighbour line if you also serve solar, and review alloy choice in our 6xxx alloy guide.

Synchronising the NEV line: pull, cool, cut as one

A battery-tray line fails differently from a window line. The section is wide and flat, so the moment pull tension dips the nose lifts and the tray comes out banana-shaped. This matters because a rejected tray is expensive — it carries far more aluminium than a window section, so each scrap piece is a larger absolute loss. The fix is not a harder pull but a steadier one: a double-pull haul-off machine hands off between grippers so tension never falls to zero, and closed-loop feedback holds it to ±2% across the whole length.

Cooling is the second failure point. A wide tray holds heat in its centre longer than its edges, so a short or uneven bed leaves a soft, wavy core. Tongzheng specifies belt-driven cooling beds long enough that the full 6–12 m tray reaches ambient before the stretcher, typically 40–60 m for a 2,500–4,000 t NEV line running at 10–15 m/min. Air quenching is tuned per alloy so 6xxx reaches the right temper without warping.

Cutting closes the loop. The single-bar saw must square the ends to ±0.5° so the tray mates to the pack and the cells sit level. Because all three stations read the same encoder, a tray leaving the die at 12 m/min is cut at 12 m/min — no stretch, no buckle, no rework. The same discipline applies to CMS beams, where consistent wall thickness protects the crash performance the OEM validated. Plants that integrate these steps report first-pass yield above 93% on tray sections that previously ran near 84%.

Profile family comparison: tray vs beam vs busbar

Not every EV profile stresses the line the same way. The three high-volume families differ in alloy, wall and the tolerance that actually bites, which is why equipment sensitivity varies so much between them.

Measuring flatness and tolerance on battery housings

Flatness on a tray is judged two ways. A straightedge-and-feeler check across the width confirms the 0.5–1.0 mm/m spec on the bench, while a 3D laser scan or coordinate-measuring machine maps the whole tray to catch twist the eye misses. Wall thickness is verified with ultrasonic or calliper sampling along the length, because a single thin spot fails the ±0.15 mm rule. Cut squareness at the cell-module interface is checked with a square and a ±0.5° gauge. Log every reading so the trend, not a single good part, proves the line is in control before series volume starts.

Specifying an EV-profile line: a checklist

• Widest tray you will make — size the press and bed for this, not the average section.

• Flatness target — confirm 0.5–1.0 mm/m and design the cooling bed length to hold it.

• Wall tolerance — set ±0.15 mm and pair it with a double-pull haul-off for steady tension.

• Cut squareness — specify ±0.5° at the cell-module interface.

• Alloy plan — confirm the 6xxx workhorse plus any 7xxx rails via our 6xxx alloy guide.

Qualification and validation before series run

Before an EV customer releases volume, the line is qualified against the drawing. A typical validation sequence:

1. Run PPAP-style samples and measure flatness, wall and cut squareness per the print.

2. Confirm first-pass yield above the contract threshold (often 93%+) on tray sections.

3. Validate the extrusion process quench and ageing give the right temper.

4. Sign off tolerance on three consecutive batches before series volume begins.

Frequently asked questions

Why are EVs so aluminium-hungry?

Batteries are heavy, so EVs trade steel for aluminium to protect range. A typical BEV uses 200–300 kg of aluminium, much of it extruded into battery trays, crash beams and busbars.

Which alloy is best for battery trays?

6xxx series (6005A, 6061, 6082) is the workhorse for trays and enclosures thanks to extrudability and strength. 7xxx is used where peak strength is needed but is harder to extrude and weld.

Why do NEV lines need wider presses?

Battery enclosures are wide, flat sections up to 300–600 mm across. Presses of 2,500–4,000 t with wide containers and flat dies produce them in one pass instead of welding many parts.

What flatness tolerance applies to battery housings?

Battery trays commonly require overall flatness within 0.5–1.0 mm/m and wall thickness tolerance of ±0.15 mm so the enclosure seals and the cells sit level.

How does equipment spec differ for NEV profiles?

Long cooling beds to keep wide flats straight, double-pull haul-offs for stable tension, and precise single-bar saws for square, burr-free cuts at the cell-module interfaces.