E-Motor Project to Drive NRW Forward as Production Location

HaPiPro2 key visual showing a hairpin stator of an electric motor Copyright: © PEM RWTH Aachen University

The chair of Production Engineering of E-Mobility Components (PEM) of RWTH Aachen University is conducting research into the production of electric motors together with numerous renowned industrial partners in the HaPiPro2 project. For the further development of the most relevant component, the so-called hairpin stator, a prototypical demonstration line is used to produce different variants of this electric motor component which is crucial for performance and efficiency.

Production processes suitable for large series

The ongoing electrification of the global vehicle fleet is leading to an increasing importance of electric traction drives (e-drives) in the automotive industry. In the future, almost every road vehicle is expected to have at least one electric motor regardless of whether they are purely battery-powered cars, vehicles with fuel cells, mild or plug-in hybrids. A key field of innovation for e-drives is stator production using the hairpin design. In contrast to conventional wire winding technology, in hairpin technology the copper windings of the electric motor are constructed from solid electrical conductors in a plug-in coil design. To this end, copper wires are first bent three-dimensionally into a U-shape and then completed by a variety of assembly, forming and contacting operations to form an electrically closed "winding". The name "hairpin" is derived from the hairpin-shaped geometry of the copper conductors. The potential for innovation lies in the assembly-based design of hairpin stators, which enables more compact and more powerful traction drives as well as more economical production processes suitable for large series.

Expensive production systems still dominate

In view of the increasing demand for hairpin stators for e-drives, economically efficient approaches and methods are needed that take into account the aspect of variant flexibility while meeting automotive requirements for high process stability. Existing approaches are usually based on highly restricted product designs as well as redundant and cost-intensive production systems. The research objective is therefore to design and test a manufacturing, production and process design for hairpin stators that is optimized in terms of variant flexibility and process stability. The objective will be measurable by a flexible and process-stable demonstration production of hairpin stators covering all steps from wire forming to secondary insulation. This should enable the entire process to be viewed holistically in order to determine cross-production process dependencies for example the influence of different wire thicknesses on the laser contacting of the copper leads.

Further information is provided in this as well as this press release.



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The project

  • "HaPiPro2": Product and production concepts for the variant-flexible hairpin stator production

Research objectives

  • Development of innovative and variant-flexible product process concepts based on a hairpin stator reference design and their testing at both individual process and overall process level
  • Investigation of the extent to which product or manufacturing changes as well as production technologies of different maturity levels can be quickly integrated into the reference process chain for a high speed of innovation
  • Identification of interdependencies between product characteristics and process parameters to increase process flexibility and process stability of hairpin stator production

Research and project partners

PEM of RWTH Aachen University
DAP of RWTH Aachen University
Ford-Werke GmbH (German)
AMS Anlagenbau GmbH & Co. KG
Berg & Co. GmbH
thyssenkrupp System Engineering GmbH


  • 08/15/2020 through 02/29/2024

Project management

Projektträger Jülich (PtJ)

Funding code

  • EFO-0011A


Ministry of Economic Affairs, Innovation, Digitization and Energy of the State of North Rhine-Westphalia (German)