High-efficiency electric motor with Additive Manufactured Cooling System in Plastic Overmold (HEaK)

Highly efficient electric motors are increasingly needed for the use of emission-free mobility solutions. In the HEaK project, additive and subtractive manufacturing processes are combined to enable an internal cooling system for a traction motor. This requires a multidisciplinary design of the electromagnetic circuit and the cooling system in the stator slot. A further development of hairpin technology will create the production engineering conditions that enable the insertion of cooling channels in the slot. To create the cooling channels, additively manufactured sections are overmolded with highly thermally conductive thermosets. To prevent the channels from collapsing due to the injection pressure, they are manufactured as closed bodies filled with powder using the Laser Powder Bed Fusion (LPBF) process. After overmolding, the additively manufactured channels can be opened and the powder removed by using a subtractive process. Process simulation is used to ensure the manufacturability of the concept, which is then practically demonstrated by implementing a prototype. This prototype is validated on the test bench. The novel concept enables a significant increase in power density.

In the project, KIT-FAST focuses on process simulation of overmolding of the additively manufactured sections in the stator encapsulation. Using fluid-structure interactions, any damage to the powder-filled structures is virtually predicted and thus the manufacturability is virtually verified.