Electric machine with cooling channel loop for stator poles

Abstract

The invention relates to an electric machine having a cooling channel loop for stator poles. An axial flux electric motor includes a rotationally fixed stator defining an axis of rotation and having a plurality of electrically conductive stator poles arranged radially about the axis of rotation. The electric motor further comprises a rotor axially spaced from one side of the stator, rotatably mounted coaxially with the axis of rotation, and having a plurality of permanent magnets (PM) arranged symmetrically about the axis of rotation and facing the stator. When current passes through the poles, torque is generated on the at least one rotor by a rotating magnetic field established via interaction between the corresponding PM and the poles. The stator also includes a plurality of cooling channel loops together surrounding each of the stator poles and configured to receive and pass a fluid therethrough to remove thermal energy from the stator poles generated by current therethrough.

Description

Technical Field

[0001] The present disclosure relates to an electric machine having a cooling channel loop for the stator poles of the machine. Background Art

[0002] An electric motor is a machine that converts electrical energy into mechanical energy. An electric motor can be configured as an alternating current (AC) or direct current (DC) type. The operation of an electric motor is based on the electromagnetic interaction between permanent magnets and the magnetic fields generated by selectively energized coils of the motor. Electric motors are classified into two categories according to the direction of the magnetic field - axial flux motors and radial flux motors.

[0003] As a by-product of the generated torque, an electric motor generates heat energy, which can negatively affect motor performance and reliability. Therefore, cooling of an electric motor can eliminate the thermal stress borne by the motor poles or windings and provide a longer motor life under peak load or near peak load. Additionally, electric motor cooling generally can make the motor operation quiet and enhance motor operation at higher speeds, and is beneficial for reducing motor inertia and packaging. Summary of the Invention

[0004] An axial flux electric motor includes a rotationally fixed stator that defines a rotational axis and has a plurality of conductive stator poles radially arranged about the rotational axis. The electric motor further includes at least one rotor axially spaced from one side of the stator, rotatably mounted coaxially with the rotational axis, each having a plurality of permanent magnets (PMs) symmetrically arranged about the rotational axis and facing the stator. When current passes through the poles, torque is generated on the at least one rotor by a rotating magnetic field established via the interaction between the corresponding PMs and the poles. The stator additionally includes a plurality of cooling channel loops that together surround each of the stator poles and are configured to receive fluid and pass the fluid therethrough to remove heat energy generated by the current passing through them from the stator poles.

[0005] Each cooling channel loop may have a corresponding separate fluid inlet and fluid outlet.

[0006] The plurality of cooling channel loops may have a single fluid inlet and a single fluid outlet.

[0007] The cooling channel loops may be arranged in a pattern of nested fluid conduits.

[0008] The cooling channel loops may overlap in a plan view, and each cooling channel loop may have a variable cross-sectional area to optimize the fluid flow distribution near the corresponding stator poles.

[0009] The cross-sectional area of each cooling channel loop can be relatively small in the region overlapping with another cooling channel loop and relatively large in the region not overlapping with another cooling channel loop.

[0010] Each cooling channel loop can extend partially around each stator pole, alternating between a radially outer portion adjacent to one stator pole and a radially inner portion of an adjacent stator pole.

[0011] Adjacent cooling channel loops can overlap and nest near the radially inner portion of the stator pole.

[0012] The stator can include an epoxy resin around the stator poles. In such an embodiment, the cooling channel loops can be defined by the epoxy resin.

[0013] Multiple cooling channel loops can be generated via sacrificial materials using additive manufacturing.

[0014] The fluid can be a dielectric coolant.

[0015] Specifically, the dielectric coolant can be automatic transmission fluid (ATF), hydrofluoroether (HFE), or perfluoropolyether (PFPE).

[0016] A motor vehicle incorporating such an axial flux electric motor is also contemplated.

[0017] The present invention provides the following technical solutions.

[0018] Technical solution 1. An axial flux electric motor, comprising:

[0019] A rotationally fixed stator that defines a rotational axis and has a plurality of conductive stator poles radially arranged around the rotational axis; and

[0020] At least one rotor axially spaced from one side of the stator, rotatably mounted coaxially with the rotational axis, each rotor having a plurality of permanent magnets (PMs) symmetrically arranged around the rotational axis and facing the stator;

[0021] Wherein:

[0022] When current passes through the poles, a torque is generated on the at least one rotor by a rotating magnetic field established via the interaction between the corresponding PMs and the poles; and

[0023] The stator additionally includes a plurality of cooling channel loops that together surround each of the stator poles and are configured to receive a fluid and pass the fluid through the cooling channel loops to remove heat energy generated by the current from the stator poles.

[0024] Aspect 2. The axial flux electric motor according to Aspect 1, wherein the plurality of cooling channel loops have a single fluid inlet and a single fluid outlet.

[0025] Aspect 3. The axial flux electric motor according to Aspect 1, wherein the plurality of cooling channel loops are arranged in a pattern of nested fluid conduits.

[0026] Aspect 4. The axial flux electric motor according to Aspect 3, wherein the cooling channel loops overlap in a plan view, and each cooling channel loop has a variable cross-sectional area to optimize the fluid flow distribution near the respective stator poles.

[0027] Aspect 5. The axial flux electric motor according to Aspect 4, wherein the cross-sectional area of each cooling channel loop is relatively small in the area overlapping with another cooling channel loop, and relatively large in the area not overlapping with another cooling channel loop.

[0028] Aspect 6. The axial flux electric motor according to Aspect 5, wherein each cooling channel loop extends partially around each stator pole, alternating between a radially outer portion near one stator pole and a radially inner portion of an adjacent stator pole.

[0029] Aspect 7. The axial flux electric motor according to Aspect 6, wherein adjacent cooling channel loops overlap and nest near the radially inner portions of the stator poles.

[0030] Aspect 8. The axial flux electric motor according to Aspect 1, further comprising an epoxy resin around the stator poles, and wherein the cooling channel loops are defined by the epoxy resin.

[0031] Aspect 9. The axial flux electric motor according to Aspect 1, wherein the fluid is a dielectric coolant.

[0032] Aspect 10. The axial flux electric motor according to Aspect 9, wherein the dielectric coolant is one of automatic transmission fluid (ATF), hydrofluoroether (HFE), and perfluoropolyether (PFPE).

[0033] Aspect 11. A motor vehicle, comprising:

[0034] An axial flux electric motor configured to generate torque for propelling the motor vehicle, the axial flux electric motor comprising:

[0035] A rotationally fixed stator defining a rotational axis and having a plurality of conductive stator poles radially arranged around the rotational axis; and

[0036] At least one rotor, which is axially spaced from one side of the stator and is rotatably mounted coaxially with the rotation axis, and each rotor has a plurality of permanent magnets (PMs) symmetrically arranged around the rotation axis and facing the stator;

[0037] Wherein:

[0038] When current passes through the magnetic poles, a torque is generated on the at least one rotor by a rotating magnetic field established through the interaction between the corresponding PMs and the magnetic poles; and

[0039] The stator additionally includes a plurality of cooling channel loops that together surround each of the stator magnetic poles and are configured to receive a fluid and pass the fluid through the cooling channel loops to remove heat energy generated by the current from the stator magnetic poles.

[0040] Technical solution 12. The motor vehicle according to technical solution 11, wherein the plurality of cooling channel loops have a single fluid inlet and a single fluid outlet.

[0041] Technical solution 13. The motor vehicle according to technical solution 11, wherein the plurality of cooling channel loops are arranged in a pattern of nested fluid conduits.

[0042] Technical solution 14. The motor vehicle according to technical solution 13, wherein the cooling channel loops overlap in a plan view, and each cooling channel loop has a variable cross-sectional area to optimize the fluid flow distribution near the corresponding stator magnetic poles.

[0043] Technical solution 15. The motor vehicle according to technical solution 14, wherein the cross-sectional area of each cooling channel loop is relatively small in the area overlapping with another cooling channel loop and relatively large in the area not overlapping with another cooling channel loop.

[0044] Technical solution 16. The motor vehicle according to technical solution 15, wherein each cooling channel loop extends partially around each stator magnetic pole, alternating between a radially outer portion near one stator magnetic pole and a radially inner portion of an adjacent stator magnetic pole.

[0045] Technical solution 17. The motor vehicle according to technical solution 16, wherein adjacent cooling channel loops overlap and are nested near the radially inner portions of the stator magnetic poles.

[0046] Aspect 18. The motor vehicle according to Aspect 11, wherein the stator includes epoxy resin around the stator poles, and wherein the cooling channel loop is defined by the epoxy resin.

[0047] Aspect 19. The motor vehicle according to Aspect 11, wherein the fluid is a dielectric coolant, and wherein the dielectric coolant is one of an automatic transmission fluid (ATF), a hydrofluoroether (HFE), and a perfluoropolyether (PFPE).

[0048] Aspect 20. An axial flux electric motor, comprising:

[0049] A rotationally fixed stator that defines a rotational axis and has a plurality of conductive stator poles radially arranged around the rotational axis; and

[0050] At least one rotor that is axially spaced from one side of the stator and is rotatably mounted coaxially with the rotational axis, each rotor having a plurality of permanent magnets (PMs) symmetrically arranged around the rotational axis and facing the stator;

[0051] Wherein: <s

[0052] When current passes through the poles, a torque is generated on the at least one rotor by a rotating magnetic field established through the interaction between the corresponding PMs and the poles; and

[0053] The stator additionally includes a plurality of cooling channel loops that together surround each of the stator poles and are configured to receive fluid and pass the fluid through the cooling channel loops to remove heat energy generated by the current from the stator poles;

[0054] The plurality of cooling channel loops are arranged in a pattern of nested fluid conduits;

[0055] The cooling channel loops overlap in a plan view, and each cooling channel loop has a variable cross-sectional area to optimize the fluid flow distribution near the corresponding stator pole;

[0056] The cross-sectional area of each cooling channel loop is relatively small in the region overlapping with another cooling channel loop and relatively large in the region not overlapping with another cooling channel loop; and

[0057] Each cooling channel loop extends partially around each stator pole, alternating between a radially outer portion near one stator pole and a radially inner portion of an adjacent stator pole.

[0058] The above features and advantages of the present disclosure, as well as other features and advantages, will become apparent from the following detailed description of the embodiments and best mode for carrying out the present disclosure when taken in conjunction with the accompanying drawings and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 is a schematic view of a motor vehicle having a powertrain employing an axial flux motor - generator for propulsion.

[0060] Figure 2 is Figure 1 a schematic exploded partial perspective view of the axial flux motor - generator shown in, depicting a stator assembly having first and second rotors according to an embodiment of the present disclosure, wherein the stator has a plurality of cooling channel loops around the stator poles.

[0061] Figure 3 is Figure 2 a schematic enlarged partial perspective view of the stator shown in, depicting a plurality of nested cooling channel loops having separate fluid inlets and outlets according to the present disclosure.

[0062] Figure 4 is Figure 2 a schematic enlarged partial perspective view of the stator cooling channel loops shown in, depicting separate cooling channel loops before and after nesting according to the present disclosure.

[0063] Figure 5 is Figure 2 a schematic enlarged partial perspective view of the stator shown in, depicting a plurality of nested cooling channel loops having one fluid inlet and one fluid outlet according to the present disclosure.

[0064] Figure 6 is Figure 2 a schematic enlarged plan view of the stator cooling channel loops shown in, depicting separate cooling channel loops fluid - connected in parallel and portions of the channel loops having an enlarged cross - sectional area according to the present disclosure.

[0065] Figure 7 is Figure 2 a schematic enlarged cross - sectional side view of the axial flux motor - generator shown in, depicting a fluid circulation arrangement according to the present disclosure, the fluid circulation arrangement including fluid channels extending into the stator to feed the cooling channel loops. DETAILED DESCRIPTION

[0066] The embodiments of the present disclosure described herein are intended to be illustrative. Other embodiments may take different and alternative forms. Additionally, the figures are generally schematic and are not necessarily drawn to scale. Some features may be exaggerated or minimized to show details of particular components. Thus, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching one skilled in the art to employ the present disclosure in various ways.

[0067] Certain terms may be used for reference purposes in the following description and are thus not intended to be limiting. For example, terms such as "above" and "below" refer to directions in the referenced figures. Terms such as "front," "rear," "forward," "rearward," "left," "right," "rear portion," and "side" describe the orientation and / or position of parts of a component or element within a consistent but arbitrary reference frame, which becomes clear by reference to the text describing the component or element in question and the associated figures. Additionally, terms such as "first," "second," "third," etc. may be used to describe separate components. Such terms may include the specifically mentioned words above, their derivatives, and words of similar meaning.

[0068] Referring Figure 1 , a motor vehicle 10 having a powertrain 12 is depicted. The vehicle 10 may include, but is not limited to, commercial vehicles, industrial vehicles, passenger vehicles, aircraft, vessels, trains, etc. It is also contemplated that the vehicle 10 may be a mobile platform, such as an airplane, an all-terrain vehicle (ATV), a boat, a personal mobility device, a robot, etc., for purposes of the present disclosure. The powertrain 12 includes a first power source 14, which is depicted as an electric motor-generator and is configured to generate a first power source torque T1 ( Figure 1 shown therein) for propelling the vehicle 10 via a driven wheel 16 (such as relative to a road surface). The motor-generator 14 is configured as an axial flux motor, where non-permanent magnetic poles are induced on the (multiple) ferromagnetic rotors of the motor that will be described in detail below.

[0069] As Figure 1As shown, the powertrain 12 may further include a second power source 20, such as an internal combustion engine, configured to generate a second power source torque T2. The power sources 14 and 20 may act in concert to power the vehicle 10 and are operatively connected to the transmission assembly 22. The transmission assembly 22 may be configured to transfer the first power source torque T1 and / or the second power source torque T2 to the final drive unit 24, which in turn may be connected to the driven wheels 16. The first power source 14 (which will be referred to as the motor-generator for the remainder of this disclosure) may be mounted, for example, to the second power source 20, to the transmission assembly 22 (or incorporated therein), to the final drive unit 24, or as a separate assembly mounted to the structure of the vehicle 10.

[0070] Alternatively, the respective first power sources 14 may be incorporated into each of the driven wheels 16, for example, as in-wheel / hub motors. As shown, the motor vehicle 10 additionally includes a programmable electronic controller 26 configured to communicate via the high voltage bus 27 and control the powertrain 12 to generate a predetermined amount of power source torque (such as the sum of T1 and T2) and to regulate various other vehicle systems. The vehicle 10 additionally includes an energy storage system 28, such as one or more batteries, configured to generate and store electrical energy for powering the power sources 14 and 20.

[0071] As Figure 2 As shown, the motor-generator 14 includes a rotationally fixed stator 30. The stator 30 defines a rotational axis X and includes a stator core 32 and a plurality of magnetic poles (e.g., coils) 34 arranged radially about the rotational axis X. The stator core 32 may be composed of a ferromagnetic material. A dielectric epoxy 35 may be disposed on the stator 30, surrounding the stator magnetic poles 34 and between the stator core 32 and the stator magnetic poles 34. The stator 30 has two opposite sides - a first side 30-1 and a second side 30-2. The motor-generator 14 further includes a first rotor 36 axially spaced from the first side 30-1 of the stator 30, creating an operating air gap therebetween. The first rotor 36 is rotatably mounted coaxially with the rotational axis X and has a first rotor outer side or surface 36-1 and an opposite rotor outer side or surface 36-2 facing the stator 30.

[0072] The motor-generator 14 may additionally include a second rotor 38 that is rotatably mounted coaxially with the axis of rotation X and axially spaced from the second side 30-2 of the stator 30. The second rotor 38 may be characterized by an outer surface 38-1 of the second rotor facing the stator 30 and an opposite outer side or surface 38-2 of the rotor. Each of the first rotor 36 and the second rotor 38 includes a plurality of permanent magnets (PMs) 40 symmetrically arranged about the axis of rotation X and facing the stator 30. When current passes through the magnetic poles, torque is generated on the first rotor 36 and / or the second rotor 38 by a rotating magnetic field established due to the interaction between the corresponding PMs 40 and the magnetic poles 34 of the stator.

[0073] Continuing to refer Figure 2 , the stator 30 additionally includes a plurality of cooling channel loops 42. Each cooling channel loop 42 may be defined by an epoxy resin 35 disposed between individual magnetic poles 34 and the stator core 32. As Figure 3 shown, the cooling channel loops 42 may be arranged in a pattern 43 of nested (i.e., overlapping and substantially intertwined) fluid conduits. Each cooling channel loop 42 may extend adjacent to at least one of the magnetic poles 34 of the stator and wrap around the magnetic poles 34 of the stator such that the plurality of loops together surround each stator magnetic pole via their respective channels. The cooling channel loops 42 may be generated via additive manufacturing using a sacrificial material such as polyvinyl alcohol (PV). Each of the cooling channel loops 42 is configured to receive a fluid 44 and pass the fluid 44 therethrough to remove thermal energy generated by current from the stator magnetic poles 34. The fluid 44 may be a dielectric coolant to prevent conduction of current therethrough. Such a dielectric coolant may be, for example, automatic transmission fluid (ATF), hydrofluoroether (HFE), or perfluoropolyether (PFPE).

[0074] As Figure 4 shown, each cooling channel loop 42, such as the first loop 42-1 and the second loop 42-2, may extend partially around each stator magnetic pole 34. Individual cooling channel loops 42 may overlap in a plan view ( Figure 3 and Figure 4 shown), and each cooling channel loop may have a variable cross-sectional area 42A to optimize the fluid flow distribution near the corresponding stator magnetic pole 34. Such an optimized fluid flow distribution may be used to target hot spots on the corresponding stator magnetic pole 34. Each cooling channel loop 42 may wrap around the magnetic poles 34 of the stator, alternating between extending in a radially outer portion 34-1 adjacent to one magnetic pole and a radially inner portion 34-2 of an adjacent magnetic pole ( Figure 3 shown).

[0075] For example, as Figure 3 and Figure 4As shown, adjacent cooling channel loops 42 may overlap and nest near the radially inner portion 34-2 of the stator pole 34. As in Figure 3 As can be seen, the cross-sectional area 42A of each cooling channel loop 42 may be relatively small in the region 46 where it overlaps with another cooling channel loop, and relatively large in the region 48 where it does not overlap with another cooling channel loop. Alternatively, as Figure 6 As shown, the cooling channel loops 42 may be fluidly connected in parallel with at least a portion of a channel loop having a variable cross-sectional area 42A, or the entire separate channel loop may have a cross-sectional area that expands relative to adjacent loops. In such an embodiment, the relatively large cross-sectional area 42A of a particular cooling channel loop 42 may be arranged near or substantially around the corresponding pole 34 or a portion thereof to target specific stator hot spots and / or poles.

[0076] Referring back to Figure 3 and Figure 4 , each cooling channel loop 42 may have a corresponding separate fluid inlet 50 and fluid outlet 52. Alternatively, as Figure 5 As shown, multiple cooling channel loops 42 (i.e., the pattern 43 of nested loops) may have a single fluid inlet 50 and a single fluid outlet 52. The (multiple) cooling channel loop inlets 50 and the (multiple) outlets 52 may be embedded in and / or mounted to the epoxy resin 35. Although not specifically shown, in another embodiment, each pole 34 may have an associated independent coolant channel loop 42 that has an accompanying separate fluid inlet 50 and separate fluid outlet 52, or such separate channel loops may be connected together to a common inlet and outlet. The cross-sectional area 42A may vary around the circumference of the stator 30 and expand near the (multiple) fluid inlets 50 and the (multiple) outlets 52 relative to the cross-sectional area elsewhere along the (multiple) cooling channel loops ( Figure 6 as shown).

[0077] Stator hot spots typically occur at approximately the midpoint between the inner diameter (ID) and the outer diameter (OD) of the stator pole 34. The cooling channel loops 42 include bridge channels 49 disposed between the stator poles 34, although the flow distribution between individual bridges may not be uniform. For example, as Figure 6 As shown, at positions arranged 180 degrees apart, such as at 90 degrees and 270 degrees relative to the fluid inlet 50 and outlet 52, there may be a minimum fluid flow through the corresponding bridge 49, which results in the aforementioned stator hot spots. The pattern 43 of the cooling channels at both the ID and OD may be configured to generate a more uniform coolant 44 flow distribution between individual bridges 49, specifically targeting the hot spots at the midpoint between the fluid inlet 50 and the fluid outlet 52.

[0078] Referring to Figure 6 the embodiment shown, from the fluid inlet 50 to the bridges 49 disposed at approximately 90 degrees and 270 degrees, the cross-sectional area 42A of the cooling channels at the OD can vary from relatively large to small, while the cross-sectional area of the cooling channels at the ID side varies conversely from small to large. The cross-sectional area 42A can vary continuously or stepwise to drive the coolant 44 from the OD to the ID through the bridge 49. From the bridges 49 disposed at approximately 90 degrees and 270 degrees to the fluid outlet 52, the cross-sectional area 42A of the cooling channels at the OD can vary from relatively small to large, while the cross-sectional area of the cooling channels at the ID side varies conversely from relatively large to small. The subject variations along the OD and ID can be used to synergistically drive the coolant 44 from the fluid inlet 50 to the fluid outlet 52 from the ID to the OD through the bridge 49 and cool the above-mentioned hot spots in the process.

[0079] As Figure 7 shown, each of the (multiple) cooling channel loop inlets 50 and (multiple) outlets 52 can be connected to a fluid pump 56 configured to pressurize and circulate the coolant 44, i.e., supply the coolant from the fluid sump to the cooling channel loop 42. The fluid pump 56 can be part of an electric motor cooling system 58 operated via an electronic controller 26. The electronic controller 26 can be programmed with an algorithm 60 to regulate the fluid pump 56 using detected (e.g., via corresponding sensors generally indicated by numeral 62) or calculated variables. These variables can be, for example, motor phase current, motor speed, the temperature of the stator 30, and the flow rate of the coolant 44 in the axial flux electric motor 14. The temperature of the stator 30 can be detected, otherwise determined, or estimated using the recent history of other sensor readings (including readings of coolant temperature) and a motor operating map 64 programmed into the controller 26. Thus, the electric motor cooling system 58 can be configured to eliminate thermal stress and provide a longer life for the electric motor 14 at higher speeds or near peak loads (such as during the propulsion of the motor vehicle 10) in addition to various other benefits.

[0080] In summary, a stator employing a pattern of nested cooling channel loops 42 using a circulating fluid provides dedicated cooling for the stator poles of an electric motor. Such nested cooling channel loops 34 allow each individual stator pole to be substantially surrounded by one or more cooling channels. The individual cooling channel loops can overlap and use variable cross-sections to optimize the fluid flow distribution near the hot spots on the stator poles. The cooling channel loops can extend through the epoxy resin disposed between the stator core and the stator poles. The circulating fluid can be a dielectric coolant to prevent the conduction of electric current therethrough.

[0081] The detailed description and the drawings or figures support and describe the present disclosure, but the scope of the present disclosure is defined only by the claims. Although the best mode for carrying out the claimed disclosure and some of the other embodiments have been described in detail, there are various alternative designs and embodiments for practicing the disclosure defined in the appended claims. In addition, the features of the embodiments shown in the drawings or various embodiments mentioned in this specification are not necessarily to be understood as separate embodiments from one another. On the contrary, it is possible that each feature described in one of the examples of an embodiment can be combined with one or more other desired features from other embodiments, resulting in other embodiments that are not described in words or by reference to the drawings. Therefore, these other embodiments fall within the framework of the scope of the appended claims.

Claims

1. An axial flux electric motor comprising: a rotationally fixed stator defining an axis of rotation and having a plurality of electrically conductive stator poles radially arranged about the axis of rotation; and at least one rotor axially spaced from one side of the stator and rotatably mounted coaxially with the rotation axis, each rotor having a plurality of permanent magnets (PM) symmetrically arranged about the rotation axis and facing the stator; in: generating torque on the at least one rotor by a rotating magnetic field established through interaction between the corresponding PM and the magnetic pole when current is passed through the magnetic pole; and The stator additionally includes a plurality of cooling channel loops that together surround each of the stator poles and are configured to receive a fluid and pass the fluid through the cooling channel loops to remove heat energy generated by the current from the stator poles.

2. The axial flux electric motor according to claim 1, wherein: The plurality of cooling channel loops have a single fluid inlet and a single fluid outlet.

3. The axial flux electric motor according to claim 1, wherein: The plurality of cooling channel loops are arranged in a pattern of nested fluid conduits.

4. The axial flux electric motor according to claim 3, wherein: The cooling channel loops overlap in plan view, and each cooling channel loop has a variable cross-sectional area to optimize fluid flow distribution near the corresponding stator pole.

5. The axial flux electric motor according to claim 4, wherein: The cross-sectional area of each cooling channel loop is relatively small in a region overlapping with another cooling channel loop, and relatively large in a region not overlapping with another cooling channel loop.

6. The axial flux electric motor according to claim 5, wherein: Each cooling channel loop extends partially around each stator pole, alternating between a radially outer portion adjacent one stator pole and a radially inner portion adjacent a stator pole.

7. The axial flux electric motor according to claim 6, wherein: Adjacent cooling channel loops overlap and nest near the radially inner portions of the stator poles.

8. The axial flux electric motor of claim 1 further comprising epoxy surrounding the stator poles, and wherein: The cooling channel loop is defined by the epoxy resin.

9. A motor vehicle comprising: An axial flux electric motor configured to generate torque for propelling the motor vehicle, the axial flux electric motor comprising: a rotationally fixed stator defining an axis of rotation and having a plurality of electrically conductive stator poles radially arranged about the axis of rotation; and at least one rotor axially spaced from one side of the stator and rotatably mounted coaxially with the rotation axis, each rotor having a plurality of permanent magnets (PM) symmetrically arranged about the rotation axis and facing the stator; in: generating torque on the at least one rotor by a rotating magnetic field established through interaction between the corresponding PM and the magnetic pole when current is passed through the magnetic pole; and The stator additionally includes a plurality of cooling channel loops that together surround each of the stator poles and are configured to receive a fluid and pass the fluid through the cooling channel loops to remove heat energy generated by the current from the stator poles.

10. An axial flux electric motor comprising: a rotationally fixed stator defining an axis of rotation and having a plurality of electrically conductive stator poles radially arranged about the axis of rotation; and at least one rotor axially spaced from one side of the stator and rotatably mounted coaxially with the rotation axis, each rotor having a plurality of permanent magnets (PM) symmetrically arranged about the rotation axis and facing the stator; in: generating torque on the at least one rotor by a rotating magnetic field established through interaction between the corresponding PM and the magnetic pole when current is passed through the magnetic pole; and The stator additionally includes a plurality of cooling channel loops that together surround each of the stator poles and are configured to receive a fluid and pass the fluid through the cooling channel loops to remove heat energy generated by the current from the stator poles; the plurality of cooling channel loops being arranged in a pattern of nested fluid conduits; The cooling channel loops overlap in plan view, and each cooling channel loop has a variable cross-sectional area to optimize fluid flow distribution near a corresponding stator pole; The cross-sectional area of each cooling channel loop is relatively small in an area overlapping with another cooling channel loop and relatively large in an area not overlapping with another cooling channel loop; and Each cooling channel loop extends partially around each stator pole, alternating between a radially outer portion adjacent one stator pole and a radially inner portion adjacent a stator pole.

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