Electric cars are an idea for the future, and electric motors have great potential, but the requirements for this technology are considerable: high speeds and increased torques, energy efficiency, lightweight and space-saving construction, and efficient resource management, to name just a few.
As part of the InCar®plus project, thyssenkrupp has successfully taken on the core of electromobility – the motor. To increase efficiency, the team at thyssenkrupp Steel Europe developed new high-strength and extra high-strength non-oriented (NO) electrical steels.
“We refer to types such as 280-30 AP as high-strength. This means that they have a guaranteed yield strength of over 400 megapascals (MPa). For extra high-strength types such as the 500Y40-35HS, the yield strength even exceeds 500 MPa,” says Marco Tietz, expert in NO electrical steel grades in Bochum.
The same high performance at a lower cost
In practice, these steel grades show lower magnetic flux leakage because the properties of this steel allow the magnets to be precisely positioned in permanent magnet excited synchronous machines.
“Using our material, it is possible to position the magnets near the very edge of the rotor, so that they can be used more effectively. This increases the torque and raises the induced voltage in the electrical machine. In addition, manufacturers can lower their costs without compromising on power and torque because less magnet material is required for comparable motor performance,” says Tietz.
But that’s not all: “We also guarantee magnetic properties for higher frequencies, for example, above 400 hertz, together with guaranteed mechanical properties.”
Lighter thanks to a new rotor shaft
At the same time, engineers at thyssenkrupp Presta Camshafts were working on developments to the rotor shaft of the drive motor. Thanks to the modular architecture of the product, they were able to introduce a hollow space inside the rotor shaft. This lowers the weight of the shaft and allows for multifunctional use. The shaft is surrounded by laminations produced in Bochum.