US Patent 10177631 Electric machine stator cooling systems and methods

An electric machine having a rotor, stator and housing. The rotor includes a radially mounted array of permanent magnets and the stator includes a plurality of electromagnets radially positioned around the rotor. The stator is encapsulated such that the stator encapsulant is in thermal contact with housing structures, for example the housing end plates. In some embodiments, the entire perimeter portion of the housing is in thermal contact with the stator or the stator encapsulant. The stator encapsulant provides for device robustness and thermal transfer from the stator to the housing. The thermal conductivity of the encapsulant may be enhanced by mixing an additive to the encapsulant to increase thermal conductivity.