BMW is installing a new electrical steel strip from steel specialist Voestalpine in the electric motors of its ‘Neue Klasse’. A cooperation agreement for this important component has been established between Voestalpine in Linz, Austria, and BMW, with the assembly to take place at BMW’s Steyr plant.
Steyr is home to the BMW Group’s largest engine plant, where it also manufactures the latest generation of e-motors for its ‘Neue Klasse’ vehicles. “The new material developed by Voestalpine combines ultra-thin electrical steel with state-of-the-art coating technology,” BMW Austria explains in a press release.
Electrical steel
Electrical steel is a type of steel with special magnetic properties that enables “the efficient conversion of electrical energy into mechanical work”, thus ensuring reliable motor operation. “High-quality electrical steel is crucial for electric motors in EVs, as it significantly contributes to the drivetrain system’s high efficiency and performance,” BMW explains.
With increasing demands on electric motors, not just any steel will do, and the trend is moving “towards ever more efficient steels combined with innovative coating systems”.
At its Linz site, Voestalpine initially produces a thin slit strip. This is further processed into electrical steel with coatings and delivered to BMW’s plant in Steyr. There, it is assembled into laminated stacks for the electric motors, which are then shipped first to Hungary, where the Debrecen plant will build the first Neue Klasse model, followed by Munich as the next production site.
Minimizing energy losses
The partners highlight the new material’s ability to minimize energy losses and reduce weight. “Using specially alloyed and thin electrical steel in combination with innovative coating systems reduces energy losses during motor operation. This results in less heat generation and thus higher motor efficiency,” explains BMW.
As the electrical steel also increases the magnetic flux density in the motor’s iron core, torque and power output improve as the magnetic flux density rises. BMW notes that using “high-permeability and strong electrical steel” also reduces the overall weight of the motor, resulting in a lighter vehicle that consumes less energy.
The conclusion is clear: the lower the motor’s energy losses, the more energy from the battery is converted into movement, extending the range. However, BMW does not quantify the effect in this case.
800-volt platform
BMW’s sixth-generation e-drives used in the Neue Klasse models are designed for the brand’s new 800-volt platform. Compared to today’s Gen5, these new motors are set to reduce energy losses by 40% and weigh 10% less, thanks to numerous measures and advancements.
BMW also continues to rely on its SSM technology (electrically excited synchronous motors) that requires no permanent magnets. All components of the Gen6 e-drive (housing, rotor, stator, gearbox, and inverter) are produced in-house at BMW Group Plant Steyr and finally assembled into complete e-drives.
