Methods and systems are provided for a cooling jacket for an electric motor. In one example, a system may include a channel extending along a circumference of an inner surface of the cooling jacket between an inlet and an outlet of the cooling jacket. A cross-section of the channel may gradually change from the inlet to the outlet along the circumference in order to compensate an increase in coolant temperature by an increase in convective heat transfer such that cooling is balanced around a circumferential surface of the electric motor.