Cooling of Motor Windings Using Additively Manufactured Heat Exchangers for Extremely High Current Density

Effective thermal management is crucial for electric machines, where windings are the primary heat source. Currently employed cooling methods, like stator jacket and oil spray cooling, require heat to travel through the stator yoke or the axial length of the windings, leading to inefficiencies. This study introduces a novel in-slot cooling design that directly integrates a 3D-printed heat exchanger with the winding, addressing the challenge of efficient heat dissipation in high-power density machines. The design features flat copper wire windings bonded to a thermally conductive, electrically insulating polymer heat exchanger, produced using additive manufacturing. By moving the coolant closer to the windings, the proposed design enhances the current-carrying capacity and lowers operating temperatures. This configuration reduces the stator slot size while significantly increasing current density in the windings and slots by factors of 2x and 3x, respectively, compared to conventional liquid-cooled machines. The results demonstrate that these integrated heat exchangers not only improve current density but also reduce machine slot size, advancing the design of high-performance electric machines suitable for diverse industrial applications.