Thin-walled injection molding for slot insulation of long stator sheet stacks

Incremental improvement of conventional traction drive technologies, product architectures, process chains and production technologies are nearly pushed to their limits. The small efforts out of extensive optimization endeavors do not lead into essential customer value any more, as efficiency cannot be increased recognizably and cost reductions vanish amongst overall drivetrain-, battery- and vehicle costs. Therefore, the introduction of new or the qualification of currently unsuited production technologies to the process chain in order to optimize efficiency, enhance functionality of components and reduce costs is an approach for holistic improvement of electric drive production. This paper presents a technology and tooling concept that enables the insulation of long stators by injection molding. Furthermore, the technological maturity and the economic and technological potential of the innovative thin-walled injection molding process as well as product implications are evaluated. It is shown, that the qualified production technology enables cost efficient production, enhances the functionality by improving the heat dissipation within the slots, widens the design possibilities of laminations and windings and is applicable for stator mass production.