BMW invests over €100m in Steyr to build EV inverter power modules in-house

BMW is pulling one of the most expensive parts of an electric drivetrain in-house. The group said on 13 October that it will invest more than €100 million in its plant in Steyr, Austria, to build power modules for inverters, with production starting in summer 2029.

What the power module does

The inverter sits between the high-voltage battery and the motor. It turns the battery's direct current into the alternating current the motor needs, and it controls how much energy flows each way. Its core is the power module: a package of power semiconductors that switch high currents and voltages very quickly. The more efficiently it switches, the less energy is lost as heat, which matters for range.

Steyr already builds BMW's Gen6 electric motors for the Neue Klasse models on two lines. In future the plant will also handle the upstream supply chain for the power module and assemble it itself. The money goes into a new cleanroom assembly line and the infrastructure around it.

New processes for BMW

To join the module's ten individual parts, BMW will use large-area soldering and ultrasonic welding, processes the company says it has never used anywhere else in the group. Local broadcaster ORF quoted plant director Harald Gottsche as saying the module is the most expensive component in the inverter, so making it in-house puts the main cost levers under BMW's own control.

In BMW's announcement, Gottsche adds that building the module internally lets the company buy components such as semiconductors flexibly on global markets, "reducing dependencies in a geopolitically sensitive technology field".

Still an engine plant, too

The move continues Steyr's shift towards electric drives, which began in 2022, but the site hasn't dropped combustion engines. According to electrive, it still supplies more than a million petrol and diesel engines a year to BMW's vehicle plants. Austrian outlet Tips reports BMW wants Steyr to produce 600,000 electric drives a year in the future.

For EV owners the payoff is indirect: carmakers that control inverter design and production can tune efficiency and cost more closely. Curious how to look after the battery those inverters draw from? See our EV battery care guide.