E-Motor Production: PEM Researches Optimization Through Vacuum Welding

10/11/2023
Graphic showing laser beam, hairpin stator, and vacuum laser welding system Copyright: © PEM RWTH Aachen University

The Chair of Production Engineering of E-Mobility Components (PEM) of RWTH Aachen University has started the "ALIVE" research project funded by the Federal Ministry for Economic Affairs and Climate Action together with its industrial partner LaVa-X. The two-year project aims to optimize the quality, costs and time required for the production of electric motors. To this end, the team wants to find out how the advantages of adaptive welding processes in a vacuum can be used for the production of the performance-determining "hairpin stator" component of electric motors.

 

New process chain and still high scrap rate

Hairpin stator technology has established itself in the development of modern motor topologies due to the high copper fill factors that can be achieved. At the same time, the corresponding processes for the production of hairpin windings still pose a key challenge. "The potential productivity of these technologies and the achievable quality level of hairpin stators cannot yet be realized because the process chain is new, which means that there is a lack of process understanding in some cases, and because there is still a high level of rejects," says PEM Director Professor Achim Kampker.

Interactions from upstream process steps

In the context of hairpin stator production, contacting of the hairpin ends by laser welding is considered a crucial stage, as it is subject to numerous process and quality-influencing interactions from upstream process steps. "The irreversible laser welding process is therefore a decisive bottleneck in terms of overall system efficiency and cycle time in the series production of hairpin technology," says Kampker.

New system for later industrial use

Laser beam welding in a vacuum has a number of advantages, however, as the reduction in working pressure greatly increases process stability and high welding depths can be achieved. The "Adaptive Laser Beam Welding in Vacuum of Hairpin Stators" (ALIVE) project therefore aims to build a vacuum laser welding system for the hairpin contacting process that can be adaptively controlled using intelligent data and could later be used on an industrial scale.

Further information on the project is provided here.