PEM Develops New Joining Technologies for E-Motor Production


The chair "Production Engineering of E-Mobility Components" (PEM) of RWTH Aachen University has successfully completed the "anfaHair" research project after two years. The aim of the project, which was funded by the Federal Ministry for Economic Affairs and Climate Action, was to make the production of new types of electric motors more efficient on an industrial scale. To this end, PEM worked with the Berlin-based mechanical engineering company Röscher to develop four potentially marketable joining technologies for the manufacturing process of so-called hairpin stators as the component of electric motors that is crucial for their performance and efficiency.

  Hairpin stator from up close Copyright: © PEM RWTH Aachen University

"We have extensively tested the new joining processes and concretely demonstrated their applicability in hairpin stator production," says PEM head Professor Achim Kampker. "In the process, we have identified technologically and economically viable use cases for all processes." The hairpin design with its plug-in coil structure made of solid copper wires is increasingly displacing conventional wire winding techniques. In the corresponding process chain, the focus is currently on laser contacting of the numerous copper ends, but welding defects in series production have so far led to high scrap rates and low system efficiency.

Increasing quality and stability of the overall process chain

The "anfaHair" research project was intended to decouple the two processes of geometric weld preparation and subsequent contacting and produce a precise joining procedure. The procedure should then be integrated into the hairpin process chain, where it should enable reproducible and dimensionally stable alignment of the copper wires prior to welding and thus increase both the quality and the stability of the overall process chain.

Industry expresses interest

In addition to its university research projects, the PEM chair also regularly works with partners from industry to optimize existing production processes in terms of sustainability or to develop new processes. The results from "anfaHair" are now to be further exploited in the form of scientific and industrial projects. Meanwhile, the partner company Röscher is planning to further develop the prototype station set up in the course of the project for industrial and serial applications. According to Röscher, initial inquiries from other companies have already been received. In parallel, the applicability of the system in related areas will be tested.

Further information on the project is provided here.