Centrifugal blower with integrated motor and blower volute which functions as a heat sink for the motor

1. A centrifugal blower, comprising:

a motor located in a motor housing;

an impeller comprising:

full blades disposed on a surface of the impeller, wherein each of the full blades comprises a first length and a first trailing edge disposed at a circumferential edge of the impeller, wherein each first trailing edge comprises a first back sweep angle of 45° to 65°; and

splitter blades disposed on the surface of the impeller, wherein each of the splitter blades comprises a second length less than the first length and a second trailing edge disposed at the circumferential edge of the impeller, wherein each second trailing edge comprises a second back sweep angle of 45° to 65°,

wherein absolute values of back sweep angles taken along a majority of the second length of the splitter blades are higher than absolute values of back sweep angles taken at corresponding points along a majority of the first length of the full blades; and

a volute, wherein the volute contacts the motor housing such that the volute is configured to actively cool the motor during operation.

2. The centrifugal blower of claim 1 , wherein the motor housing comprises a finned radiator on its outer surface, and the volute directly contacts the finned radiator.

3. The centrifugal blower of claim 2 , wherein:

the impeller is mounted directly on a shaft of the motor;

the volute has an elliptical shape which is at least two times wider in a direction parallel to the shaft than it is taller in a direction perpendicular to the shaft; and

the volute surrounds at least portions of the finned radiator.

4. The centrifugal blower of claim 1 , wherein the motor lacks a cooling fan.

5. The centrifugal blower of claim 1 , wherein the volute overlaps at least 20% of the motor housing.

6. The centrifugal blower of claim 5 , wherein the volute is disposed substantially radially outward of the motor housing on opposite sides of the impeller.

7. The centrifugal blower of claim 6 , wherein the volute overlaps a volute inlet channel that surrounds the impeller.

8. The centrifugal blower of claim 1 , wherein:

each first trailing edge comprises a first lean angle of 35° to 45° toward a direction of rotation of the impeller; and

each second trailing edge comprises a second lean angle of 35° to 45° toward the direction of rotation of the impeller.

9. A fuel cell system, comprising:

a fuel cell stack; and

the centrifugal blower of claim 1 .

10. A method of operating the centrifugal blower of claim 1 , comprising:

operating the centrifugal blower to blow air; and

using air flowing through the volute to actively cool the motor during operation of the blower.