Electric motor-driven compressor having bi-directional liquid coolant passage

An electric motor-driven compressor comprising:

• a housing assembly comprising a motor housing and a first compressor housing mounted to one end of the motor housing, the motor housing containing a motor stator and a motor rotor having a shaft, the motor housing defining a bore through which the motor rotor and the shaft pass;
• the first compressor housing containing a first centrifugal compressor wheel that is mounted on one end of the shaft for rotation therewith, the first compressor housing also defining a first compressor flow path including a first air inlet that leads air into the first compressor wheel, and a first volute that collects compressed air that has passed through and been compressed by the first compressor wheel;
• and
• the motor housing defining a convoluted liquid coolant passage therein, the coolant passage defining an inlet and an outlet respectively located proximate opposite ends of the motor housing, the coolant passage defining a plurality of axially spaced-apart, convoluted passageways arranged for serial flow of liquid coolant from the inlet, then through each of the convoluted passageways one after another, and finally out from the outlet.