Advancing E-Mobility with Direct Cooling Technology
The Chair of Production Engineering of E-Mobility Components (PEM) at RWTH Aachen University has initiated groundbreaking research on improving electric motor efficiency. Partnering with industry leaders, the team is working on the HNTR project, a two-year initiative funded by the German Federal Ministry for Economic Affairs and Climate Action. This project focuses on refining the manufacturing process of hairpin stators, allowing the integration of rectangular hollow conductor. These specialized conductors facilitate direct cooling, replacing conventional indirect methods that have limited efficiency. As electric mobility advances, optimizing thermal management remains a significant challenge in maintaining performance and compact motor designs.
Hollow Conductors: Unlocking Performance and Efficiency
Hollow conductors, which feature a continuous cavity for liquid coolant flow, offer a superior alternative for managing heat in electric motors. By circulating cooling media directly through these copper conductors, heat dissipation from the active winding improves significantly. Unlike traditional designs that rely on cooling the winding head or lamination stack, this innovation targets the core heat source, enhancing motor efficiency and durability. The flexibility in conductor shapes—ranging from rectangular to circular—further expands their applicability. According to PEM project manager Till Backes, integrating this technology can substantially boost the performance of electric drive systems, marking a transformative step in e-mobility production.
Challenges in Adapting Generator Cooling Techniques
While direct liquid cooling has been successfully implemented in large-scale generators, applying similar methods to compact electric motors presents unique challenges. Industrial generators, often exceeding 1,800 megawatts, use hydrogen and pure water for cooling. However, these systems feature vastly different geometric dimensions compared to automotive motors. The stator winding manufacturing techniques used for large generators are not directly transferable due to the stringent quality requirements and mass production demands in the automotive sector. Professor Achim Kampker emphasizes that refining bending and contacting processes is crucial for successfully integrating hollow conductors into e-motor production. Overcoming these hurdles will be key to unlocking the full potential of this innovative cooling technology.
