TECHNICAL FIELD

The present disclosure relates to electric machines and more specifically to electric machines that include hairpin windings.

BACKGROUND

Vehicles such as fully electric vehicles and hybrid-electric vehicles contain a traction-battery assembly to act as an energy source for the vehicle. The traction battery may include components and systems to assist in managing vehicle performance and operations. The traction battery may also include high-voltage components, and an air or liquid thermal-management system to control the temperature of the battery. The traction battery is electrically connected to an electric machine that provides torque to driven wheels. Electric machines typically include a stator and a rotor that cooperate to convert electrical energy into mechanical motion or vice versa.

SUMMARY

According to one embodiment, an electric machine includes a stator core defining slots and a single-layer winding disposed in the core and having first and second parallel paths. Each path includes hairpins interconnected to form a continuous circuit between a terminal and a neutral. The hairpins of the first path include a first type of hairpins (first hairpins) each having a first leg, a second leg, a crown connecting between the legs, an outwardly extending twist joined to the first leg, and an inwardly extending twist joined to the second leg, wherein the legs are spaced apart by a span of five slots, and a second type of hairpins (second hairpins) each having a first leg, a second leg, a crown connecting between the legs, an inwardly extending twist joined to the first leg, and an outwardly extending twist joined to the second leg, wherein the legs are spaced apart by a span of seven slots.

According to another embodiment, an electric machine includes a stator core defining slots having a plurality of radial positions, and a plurality of hairpins each having legs disposed in corresponding ones of the slots and twists extending from the legs. The hairpins are inserted into the stator core with corresponding ones of the twists connected to form a three-phase winding. For each of the radial positions, the twists extend from their respective legs in a same circumferential direction of the stator core.

According to yet another embodiment, an electric machine includes a stator core defining slots and a winding disposed in the core and having at least two parallel paths including hairpins interconnected to form at least two continuous circuits between a terminal and a neutral. The hairpins of each path include a first type of hairpins (first hairpins) each having first and second legs spaced apart by a span of five slots, and a second type of hairpins (second hairpins) each having first and second legs spaced apart by a span of seven slots.

