Custom Battery Boxes Thermoforming in polypropylene for Ev Charging at 2 mm

Vacuum formed battery boxes are used across EV charging because they can be produced without the tooling spend of injection moulding and without the weight of sheet metal. This page covers how 2 mm polypropylene sheet is formed for EV charging, what tolerances are realistic, and what has to be on the drawing before tooling starts.

The route below is the one used for most of the battery boxes shipped from this plant: sheet is heated on the forming machine, drawn over an aluminium or composite mould, cooled on a jig, then trimmed on a 5-axis router. For battery boxes the sheet gauge is selected from the load case rather than from habit, and polypropylene is the material most often specified for this combination.

Typical specification

Where these parts are used

• wallbox covers for EV charging
• payment terminal bezels for EV charging
• cable management panels for EV charging
• charger housings for EV charging
• battery boxes in general EV charging builds

How the part is made

1. Drawings are reviewed and a manufacturability report is issued with wall thickness, draft and radii marked up.
2. Tooling is cut: aluminium for production volumes, composite or printed moulds for samples and first articles.
3. Sheet is dried when the material needs it, then heated to forming temperature on the machine.
4. The sheet is formed over the mould with vacuum and, where the draw is deep, with plug assist.
5. The part cools on a jig so the shape is held while the material stabilises.
6. Trimming is done on 5-axis routers or with a dedicated trim fixture to meet the drawing.
7. Parts are inspected, fitted with inserts or hardware if required, packed and shipped.

Material notes: polypropylene

Polypropylene survives repeated impact and most cleaning chemicals. Its low forming temperature keeps cycles short, but it shrinks more, so the mould is cut with the shrink factor built in.

Design tips for this part

• keep a draft angle of at least 3 degrees on vertical walls so the part releases cleanly
• hold the draw ratio near 1:1 for deep parts, or specify plug assist
• use corner radii of at least three times the sheet thickness to avoid thinning
• plan the trim line on a flat face so the router can hold tolerance
• avoid sharp steps in the mould, which show as chill marks on the finished surface

Quality and inspection

First article inspection covers critical dimensions, wall thickness, colour and texture against the approved sample. Sheet thickness is checked on the formed part at the points shown on the drawing, and the readings go into the report.

Cost and lead time

Tooling is the main cost driver at low volume, so a 2 mm battery boxes for EV charging is usually quoted with a composite or printed mould first and the aluminium tool cut once the design is frozen. That keeps the first article cost low and gives a real part to test before the production tool exists. The result is better appearance compared with the alternatives, and a piece price that stays stable across repeat releases.

• Sample tooling: 7–15 working days
• Production tooling: 3–4 weeks
• Repeat orders run on stored tooling with no new proving run

Frequently asked questions

What quantities make sense?

Vacuum forming pays off from roughly 25 pieces up to several thousand a year. Below that, printed or composite tooling keeps the setup cost low.

Do you supply certificates?

Material certificates, dimensional reports and flame retardancy or food contact declarations are issued with the shipment where the specification requires them.

What do you need to quote?

A 3D file or drawing, the material if it is fixed, the annual quantity and the finish. Photos of the current part are enough for a first estimate.

Getting started

Send the drawing or a photo of the current battery boxes with the quantity and the finish. The first reply is a manufacturability review with the wall thickness, material and a quotation, so the decision is made on facts rather than on a price alone.