TECHNICAL FIELD

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

BACKGROUND

Vehicles such as battery-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 circumferentially arranged slots alternating between odd and even slots. Each slot has radial pin positions arranged in adjacent pairs to define radial layers. A hairpin winding includes a first path of interconnected hairpins that is disposed in the stator core such that, for each of the radial layers, the first path is disposed in the odd slots and the even slots a same number of times.

According to another embodiment, an electric machine includes a stator core defining circumferentially arranged slots. Each slot has radial pin positions arranged in adjacent pairs to define radial layers. A first phase of a hairpin winding includes a plurality of first hairpins interconnected to each other without a jumper to form a first winding path. The first hairpins have first short-pitch pins and first long-pitch pins. The first path is disposed in corresponding ones of the slots such that one of the first short-pitch pins and one of the first long-pitch pins are disposed in each of the radial layers. The first phase of a hairpin winding further includes a plurality of second hairpins interconnected to each other without a jumper to form a second winding path. The second hairpins have second short-pitch pins and second long-pitch pins. The second path is disposed in corresponding ones of the slots such that one of the second short-pitch pins and one of the second long-pitch pins are disposed in each of the radial layers.

According to yet another embodiment, an electric machine includes a stator core defining circumferentially arranged slots that each have radial pin positions arranged in adjacent pairs to define radial layers. A first phase of a hairpin winding includes a plurality of first hairpins interconnected to each other without a jumper to form a first winding path. The first hairpins have first short-pitch pins and first long-pitch pins. The first path is disposed in corresponding ones of the slots such that one of the first short-pitch pins and one of the first long-pitch pins are disposed in each of the radial layers. The first phase of a hairpin winding further includes a plurality of second hairpins interconnected to each other without a jumper to form a second winding path. The second hairpins have second short-pitch pins and second long-pitch pins. The second path is disposed in corresponding ones of the slots such that one of the second short-pitch pins and one of the second long-pitch pins are disposed in each of the radial layers. The first phase of a hairpin also winding includes a plurality of third hairpins interconnected to each other without a jumper to form a third winding path. The third hairpins have third short-pitch pins and third long-pitch pins. The third path is disposed in corresponding ones of the slots such that one of the third short-pitch pins and one of the third long-pitch pins are disposed in each of the radial layers. The first phase of a hairpin winding additionally includes a plurality of fourth hairpins interconnected to each other without a jumper to form a fourth winding path. The fourth hairpins have fourth short-pitch pins and fourth long-pitch pins. The fourth path is disposed in corresponding ones of the slots such that one of the fourth short-pitch pins and one of the fourth long-pitch pins is disposed in each of the radial layers. A first neutral bridge is connected to the first and second paths, and a second neutral bridge connected to the third and fourth paths.

