Electric motor

Abstract

The present application relates to an electric motor. The electric motor comprises an electric motor housing and a stator core. The electric motor housing has a liquid inlet. The stator core is arranged inside the electric motor housing; the stator core comprises an annular stator yoke and a plurality of stator teeth distributed at intervals in the circumferential direction of the stator yoke, and the stator core further comprises a first end face located on one axial end and a second end face located on the other axial end. A first tooth root cooling channel extending in the axial direction of the stator core is provided at the tooth roots of the stator teeth, and the first tooth root cooling channel comprises a first inlet and a first outlet, the first inlet being arranged between the first end face and the second end face, and the first outlet being arranged on the second end face; and in the axial direction of the stator core, the liquid inlet is closer to the first outlet than the first inlet, and a first outer cooling channel bringing the liquid inlet into communication with the first inlet is formed between the electric motor housing and the stator core.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese Patent Application No. 202410830386.2, filed on June 25, 2024, which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present disclosure relates to, but is not limited to, the field of motor cooling technologies, and in particular to an electric motor. BACKGROUND

[0003] A stator core of an electric motor includes a plurality of stator teeth arranged in a circumferential direction, a stator slot is defined between any two adjacent stator teeth, and a stator winding is mounted in the stator slot. Therefore, the highest temperature point of the stator core is at the stator slot. At present, most motor stators are cooled by means of a coolant. Specifically, holes are provided in a yoke of the stator, and the coolant flows through the holes to take away heat from the stator core, thereby cooling the stator core. SUMMARY

[0004] The following is a summary of subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0005] The present disclosure provides an electric motor, which can enable cooling of the highest temperature point of a stator core.

[0006] An electric motor includes: a motor housing including a coolant inlet; and a stator core disposed inside the motor housing, where the stator core includes an annular stator yoke and a plurality of stator teeth distributed at intervals in a circumferential direction of the stator yoke, and the stator core further includes a first end face on one axial end thereof and a second end face on the other axial end thereof. A first tooth-root cooling channel is provided at a tooth-root of at least one of the stator teeth and extends in an axial direction of the stator core. The first tooth-root cooling channel includes a first inlet and a first outlet, where the first inlet is disposed between the first end face and the second end face, and the first outlet is disposed on the second end face. In the axial direction of the stator core, the coolant inlet is closer to the first outlet than the first inlet. A first outer cooling channel is defined between the motor housing and the stator core, and is configured to communicate the coolant inlet with the first inlet.

[0007] Optionally, a second tooth-root cooling channel is provided at a tooth-root of at least one of the stator teeth and extends in the axial direction of the stator core. The second tooth-root cooling channel includes a second inlet and a second outlet, where the second inlet is disposed between the first end face and the second end face, and the second outlet is disposed on the first end face. In the axial direction of the stator core, the coolant inlet is closer to the second outlet than the second inlet. A second outer cooling channel is further defined between the motor housing and the stator core, and is configured to communicate the coolant inlet with the second inlet.

[0008] Optionally, the stator core includes a plurality of laminations stacked in the axial direction, where each of the laminations includes an annular yoke portion and a plurality of tooth portions distributed at intervals in a circumferential direction of the yoke portion. The yoke portions of the plurality of laminations are stacked to form the stator yoke, and the tooth portions of the plurality of laminations are stacked to form the stator teeth.

[0009] Optionally, the plurality of laminations include a first lamination located at the one axial end of the stator core, a second lamination located at the other axial end of the stator core, a plurality of third laminations located between the first lamination and the second lamination, and a fourth lamination located between the first lamination and the plurality of third laminations. The fourth lamination is provided with the first inlet, and the second lamination is provided with the first outlet. A first hole is provided at a tooth-root of at least one tooth portion of each of the third laminations, corresponding first holes of the plurality of third laminations are coaxially arranged to form the first tooth-root cooling channel, and the first lamination blocks the first holes.

[0010] Optionally, the first inlet is a first notch extending in a radial direction of the fourth lamination.

[0011] Optionally, the first notch has an opening size that gradually decreases from outside to inside, where an end of the first notch with a larger opening is in communication with the first outer cooling channel, and an end of the first notch with a smaller opening is in communication with the corresponding first holes of the third laminations.

[0012] Optionally, the plurality of laminations further include a fifth lamination located between the second lamination and the plurality of third laminations. The fifth lamination is provided with the second inlet, and the first lamination is provided with the second outlet. A second hole is provided at a tooth-root of at least one tooth portion of each of the third laminations, corresponding second holes of the plurality of third laminations are coaxially arranged to form the second tooth-root cooling channel, the second lamination blocks the second holes, and the second hole is arranged alternately with the first hole.

[0013] Optionally, the second inlet is a second notch extending in a radial direction of the fifth lamination.

[0014] Optionally, the second notch has an opening size that gradually decreases from outside to inside, where an end of the second notch with a larger opening is in communication with the second outer cooling channel, and an end of the second notch with a smaller opening is in communication with the corresponding second holes of the third laminations.

[0015] Optionally, the number of the third laminations is greater than that of each of the first lamination, the second lamination, the fourth lamination, and the fifth lamination.

[0016] Optionally, the number of the first lamination is one, the number of the second lamination is one, the number of the fourth lamination is one, and the number of the fifth lamination is one.

[0017] Optionally, the plurality of laminations are fixed to one another by bonding.

[0018] Optionally, the first lamination has the same structure as the second lamination.

[0019] Optionally, the stator core is connected to the motor housing by a fastener.

[0020] Optionally, the electric motor further includes: a motor housing cover detachably connected to the motor housing and configured to seal the motor housing.

[0021] The present disclosure provides an electric motor, where a first tooth-root cooling channel is provided at a tooth-root of at least one of the stator teeth and extends in an axial direction of a stator core. Since the tooth-root is closer to a stator slot, cooling of the stator slot can be realized, and in turn cooling of the highest temperature point of the stator core can be realized, resulting in a better cooling effect. In addition, a coolant inlet is arranged closer to a first outlet than a first inlet, and the coolant inlet is in communication with the first inlet through a first outer cooling channel, so that a coolant first contacts a stator yoke from an outer side of the stator core, and then flows into the first tooth-root cooling channel through the first inlet. On the one hand, cooling of the stator yoke is realized. On the other hand, a length of the first tooth-root cooling channel is increased, so that a flow path of the coolant in the first tooth-root cooling channel is longer, resulting in a better cooling effect on the stator slot.

[0022] Other aspects will become apparent upon reading and understanding the accompanying drawings and the detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0023] FIG. 1 is a cross-sectional view illustrating a partial structure of an electric motor according to an exemplary embodiment of the present disclosure.

[0024] FIG. 2 is a schematic diagram illustrating a stator core according to an exemplary embodiment of the present disclosure.

[0025] FIG. 3 is another cross-sectional view illustrating a partial structure of an electric motor according to an exemplary embodiment of the present disclosure.

[0026] FIG. 4 is an exploded view of the stator core shown in FIG. 2.

[0027] FIG. 5 is a schematic diagram of a first lamination.

[0028] FIG. 6 is a schematic diagram of a second lamination.

[0029] FIG. 7 is a schematic diagram of a third lamination.

[0030] FIG. 8 is a schematic diagram of a fourth lamination.

[0031] FIG. 9 is a schematic diagram of a fifth lamination.

[0032] FIG. 10 is a schematic diagram of a motor housing cover.

[0033] Description of reference numerals: 100 motor; 10 motor housing; 11 coolant inlet; 12 first outer cooling channel; 13 second outer cooling channel; 20 stator core; 21 stator yoke; 22 stator tooth; 213 stator slot; 214 tooth-root; 23 first end face; 24 second end face; 25 first tooth-root cooling channel; 250 first inlet; 251 first outlet; 26 second tooth-root cooling channel; 260 second inlet; 261 second outlet; 201 lamination; 201a first lamination; 201b second lamination; 201c third lamination; 201d fourth lamination; 201e fifth lamination; 2010 protrusion; 2011 yoke portion; 2012 tooth portion; 2013 slot portion; 2014 first hole; 2015 first notch; 2016 second hole; 2017 second notch; 2016’ first communication hole; 2014’ second communication hole; and 30 motor housing cover; 31 connection protrusion. DETAILED DESCRIPTION

[0034] The technical solutions in embodiments (or referred to as “implementations”) of the present disclosure will be clearly and completely described herein with reference to the accompanying drawings. When the following description refers to the drawings, the same numerals in different drawings indicate the same or similar elements, unless otherwise indicated.

[0035] If a term indicating a directional indication or positional relationship (e.g., upper, lower, left, right, front, rear, inner, outer, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.) is used in the embodiments of the present disclosure, such a term is merely used to explain the relative positional relationship, movement, etc. between components in a particular orientation (as shown in the drawings); and if the particular orientation changes, the directional indication or positional relationship changes accordingly. Additionally, terms such as “first” and “second” used in the embodiments of the present disclosure are merely for convenience of description, and are not to be construed as indicating or implying relative importance.

[0036] The present disclosure provides an electric motor 100.

[0037] Referring to FIG. 1 and FIG. 2, FIG. 1 is a cross-sectional view of a partial structure of an electric motor 100 according to the present disclosure, and FIG. 2 is a schematic diagram of a stator core 20.

[0038] The electric motor 100 includes a motor housing 10 and the stator core 20 disposed inside the motor housing 10. The motor housing 10 includes a coolant inlet 11 through which a coolant is introduced. The coolant includes, but is not limited to, a cooling oil.

[0039] A first gap is reserved between the motor housing 10 and the stator core 20, and defines a first outer cooling channel 12 in communication with the coolant inlet 11.

[0040] The stator core 20 includes an annular stator yoke 21 and a plurality of stator teeth 22 distributed at intervals in a circumferential direction of the stator yoke 21. The plurality of stator teeth 22 may be uniformly distributed around an axis O of the stator core 20. A stator slot 213 is defined between any two adjacent stator teeth 22, and a stator winding (not shown) is mounted in the stator slot 213. The specific number of the stator teeth 22 is not limited.

[0041] The plurality of stator teeth 22 are formed at a side of the stator yoke 21 facing a rotor of the electric motor 100. In the embodiment shown in FIG. 2, the stator core 20 is an inner stator core, the plurality of stator teeth 22 are formed on an inner circumference of the stator yoke 21, and a hollow portion of the stator core 20 is used for mounting the rotor. In other embodiments, the stator core 20 may be an outer stator core, that is, the plurality of stator teeth 22 are formed on an outer circumference of the stator yoke 21, and the rotor is disposed around an outer side of the stator core. The present disclosure will be described by taking the inner stator core as an example.

[0042] The stator core 20 further includes a first end face 23 on one axial end thereof and a second end face 24 on the other axial end thereof. A first tooth-root cooling channel 25 is provided at a tooth-root 214 of at least one of the stator teeth 22 and extends in an axial direction of the stator core 20. As used herein, the “tooth-root” refers to the position where the stator tooth 22 is connected to the stator yoke 21. The first tooth-root cooling channel 25 includes a first inlet 250 and a first outlet 251. The first inlet 250 is disposed between the first end face 23 and the second end face 24, and the first outlet 251 is disposed on the second end face 24. The first outer cooling channel 12 communicates the coolant inlet 11 with the first inlet 250. In the axial direction of the stator core 20, the coolant inlet 11 is closer to the first outlet 251 than the first inlet 250.

[0043] According to the above description, the stator core 20 is provided with the first tooth-root cooling channel 25, which is provided at the tooth-root 214 of the at least one of the stator teeth 22 and extends in the axial direction of the stator core 20. Since the tooth-root 214 is closer to the stator slot 213, cooling of the stator slot 213 can be realized, and in turn cooling of the highest temperature point of the stator core 20 can be realized, resulting in a better cooling effect.

[0044] It should also be noted that the coolant inlet 11 is disposed closer to the first outlet 251 than the first inlet 250, and the coolant inlet 11 is in communication with the first inlet 250 through the first outer cooling channel 12, so that the coolant first contacts the stator yoke 21 from an outer side of the stator core 20, and then flows into the first tooth-root cooling channel 25 through the first inlet 250. On the one hand, cooling of the stator yoke 21 is realized. On the other hand, a length of the first tooth-root cooling channel 25 is increased, so that a flow path of the coolant in the first tooth-root cooling channel 25 is longer, resulting in a better cooling effect on the stator slot 213. The dashed lines and arrows in FIG. 1 illustrate the flow path and direction of the coolant in the first tooth-root cooling channel 25.

[0045] Referring to FIG. 2 and FIG. 3, FIG. 3 is another cross-sectional view of a partial structure of the electric motor 100.

[0046] In an embodiment, a second tooth-root cooling channel 26 is provided at a tooth-root 214 of at least one of the stator teeth 22 and extends in the axial direction of the stator core 20. The second tooth-root cooling channel 26 includes a second inlet 260 and a second outlet 261. The second inlet 260 is disposed between the first end face 23 and the second end face 24, and the second outlet 261 is disposed on the first end face 23. Moreover, in the axial direction of the stator core 20, the coolant inlet 11 is closer to the second outlet 261 than the second inlet 260. A second gap is reserved between the motor housing 10 and the stator core 20, and forms a second outer cooling channel 13 communicating the coolant inlet 11 with the second inlet 260. In this way, the second outer cooling channel 13 and the first outer cooling channel 12 operate in parallel with each other. The coolant introduced from the coolant inlet 11 flows to the two axial ends of the stator core 20 along the first outer cooling channel 12 and the second outer cooling channel 13, respectively, and flows through the tooth-roots 214 of the stator teeth 22 through the first inlet 250 and the second inlet 260, respectively, which facilitates uniform cooling of various portions of the stator core 20.

[0047] In the embodiment shown in FIG. 2, a plurality of first tooth-root cooling channels 25 are provided, a plurality of second tooth-root cooling channels 26 are provided, and the plurality of first tooth-root cooling channels 25 are arranged alternately with the plurality of second tooth-root cooling channels 26. The first outlet 251 of each first tooth-root cooling channel 25 is disposed on the second end face 24, and the coolant entering each first tooth-root cooling channel 25 is ejected from the first outlet 251. The second outlet 261 of each second tooth-root cooling channel 26 is disposed on the first end face 23, and the coolant entering each second tooth-root cooling channel 26 is ejected from the second outlet 261.

[0048] Referring to FIG. 4 to FIG. 9, FIG. 4 is an exploded view of the stator core 20, FIG. 5 is a schematic diagram of a first lamination 201a, FIG. 6 is a schematic diagram of a second lamination 201b, FIG. 7 is a schematic diagram of a third lamination 201c, FIG. 8 is a schematic diagram of a fourth lamination 201d, and FIG. 9 is a schematic diagram of a fifth lamination 201e.

[0049] The stator core 20 includes a plurality of laminations 201 stacked in the axial direction, and each of the laminations 201 includes an annular yoke portion 2011 and a plurality of tooth portions 2012 distributed at intervals in a circumferential direction of the yoke portion 2011 (refer to FIG. 5). The yoke portions 2011 of the plurality of laminations 201 are stacked to form the stator yoke 21, and the tooth portions 2012 of the plurality of laminations 201 are stacked to form the stator teeth 22. A slot portion 2013 is defined between two adjacent tooth portions 2012, and the slot portions 2013 of the plurality of laminations 201 are aligned to form the stator slots 213.

[0050] The plurality of laminations 201 include a first lamination 201a located at one axial end of the stator core 20, a second lamination 201b located at the other axial end of the stator core 20, a plurality of third laminations 201c located between the first lamination 201a and the second lamination 201b, and a fourth lamination 201d located between the first lamination 201a and the plurality of third laminations 201c. An outer end face of the first lamination 201a forms the first end face 23, and an outer end face of the second lamination 201b forms the second end face 24.

[0051] The fourth lamination 201d is provided with the first inlet 250, and the second lamination 201b is provided with the first outlet 251. For each of the third laminations 201c, a first hole 2014 is provided at a tooth-root of at least one tooth portion 2012. Corresponding first holes 2014 of the plurality of third laminations 201c are coaxially arranged to form the first tooth-root cooling channel 25, and the first lamination 201a blocks the first holes 2014, so as to ensure that the first tooth-root cooling channel 25 extends along a preset path. In this way, the coolant flows from the coolant inlet 11 to the first outlet 251 via the first outer cooling channel 12, the first inlet 250, and the first tooth-root cooling channel 25.

[0052] In the embodiment shown in FIG. 4, the number of the third laminations 201c is greater than that of any other lamination 201, so that a length of the first tooth-root cooling channel 25 can be increased. In an embodiment where there are a relatively large number of third laminations 201c, the third laminations 201c may be assembled into a plurality of lamination groups stacked on top of one another, with each lamination group including multiple third laminations 201c. The number of the first lamination 201a is one, and the number of the fourth lamination 201d is one, so that the number of the third laminations 201c can be increased appropriately. However, the present disclosure is not limited thereto.

[0053] In the embodiment shown in FIG. 6, a plurality of first outlets 251 are provided, and one first outlet 251 may be provided every other tooth portion 2012. In the embodiment shown in FIG. 7, a plurality of first holes 2014 are provided, and the plurality of first holes 2014 are in one-to-one communication with the plurality of first outlets 251.

[0054] The specific manner in which the first inlet 250 is formed at the fourth lamination 201d is not limited. In an embodiment, an outer diameter of the fourth lamination 201d may be set to be smaller than outer diameters of the first lamination 201a and the third lamination 201c. Moreover, in an orthographic projection along the axial direction of the stator core 20, a projection area of the fourth lamination 201d is located outside a projection area of the first holes 2014. In this way, the first outer cooling channel 12 can be brought into communication with the first tooth-root cooling channel 25 through the space at an outer periphery of the fourth lamination 201d, with the space at the outer periphery of the fourth lamination 201d forming the first inlet 250.

[0055] In this embodiment, as shown in FIG. 8, the fourth lamination 201d is provided with a first notch 2015 extending in a radial direction. The first notch 2015 is in communication with the first outer cooling channel 12 and is also in communication with the first hole 2014. In this way, the first notch 2015 forms the first inlet 250. On the one hand, it can be ensured that the coolant enters the first tooth-root cooling channel 25 from the first notch 2015. On the other hand, the outer diameter of the fourth lamination 201d can be set to be the same as the outer diameters of the first lamination 201a and the third lamination 201c, so as to reduce the electromagnetic loss.

[0056] The specific shape of the first notch 2015 is not limited. In the embodiment shown in FIG. 8, an opening size of the first notch 2015 gradually decreases from the outside to the inside, an end of the first notch 2015 with a larger opening is in communication with the first outer cooling channel 12, and an end of the first notch 2015 with a smaller opening is in communication with the first hole 2014, so that the flow guidance can be realized. The number of the first notch 2015 is the same as the number of the first holes 2014, and a plurality of first notches 2015 are in one-to-one communication with the plurality of first holes 2014.

[0057] In the embodiment shown in FIG. 4, the plurality of laminations 201 further includes a fifth lamination 201e between the second lamination 201b and the plurality of third laminations 201c. The fifth lamination 201e is provided with the second inlet 260, and the first lamination 201a is provided with the second outlet 261. For each of the third laminations 201c, a second hole 2016 is provided at a tooth-root of at least one tooth portion 2012. Corresponding second holes 2016 of the plurality of third laminations 201c are coaxially arranged to form the second tooth-root cooling channel 26, and the second lamination 201b blocks the second holes 2016, so as to ensure that the second tooth-root cooling channel 26 extends along a preset path. In this way, the coolant flows from the coolant inlet 11 to the second outlet 261 via the second outer cooling channel 13, the second inlet 260, and the second tooth-root cooling channel 26.

[0058] In the embodiment shown in FIG. 5, a plurality of second outlets 261 are provided, and one second outlet 261 may be provided every other tooth portion 2012. In the embodiment shown in FIG. 7, a plurality of second holes 2016 are provided, and the plurality of second holes 2016 are in one-to-one communication with the plurality of second outlets 261. The first holes 2014 may be arranged alternately with the second holes 2016. For example, one second hole 2016 is arranged between every two adjacent first holes 2014. However, the present disclosure is not limited thereto.

[0059] It should also be noted that, as shown in FIGS. 8 and 9, the fourth lamination 201d is further provided with a first communication hole 2016’, which is configured to communicate the second hole 2016 with the second outlet 261. A plurality of first communication holes 2016’ may be provided, and are in one-to-one communication with the plurality of second holes 2016, and are in one-to-one communication with the plurality of second outlets 261. The fifth lamination 201e is further provided with a second communication hole 2014’, which is configured to communicate the first hole 2014 with the first outlet 251. A plurality of second communication holes 2014’ may be provided, and are in one-to-one communication with the plurality of first holes 2014, and are in one-to-one communication with the plurality of first outlets 251.

[0060] In an embodiment, as shown in FIG. 9, the fifth lamination 201e is provided with a second notch 2017 extending in a radial direction. The second notch 2017 is in communication with the second outer cooling channel 13 and is also in communication with the second hole 2016. In this way, the second notch 2017 forms the second inlet 260. On the one hand, it can be ensured that the coolant enters the second tooth-root cooling channel 26 from the second notch 2017. On the other hand, an outer diameter of the fifth lamination 201e can be set to be the same as outer diameters of the second lamination 201b and the third lamination 201c, so as to reduce the electromagnetic loss.

[0061] The specific shape of the second notch 2017 is not limited. In the embodiment shown in FIG. 9, an opening size of the second notch 2017 gradually decreases from the outside to the inside, an end of the second notch 2017 with a larger opening is in communication with the second outer cooling channel 13, and an end of the second notch 2017 with a smaller opening is in communication with the second hole 2016, so that the flow guidance can be realized. The number of the second notch 2017 is the same as the number of the second holes 2016, and a plurality of second notches 2017 are in one-to-one communication with the plurality of second holes 2016.

[0062] In an embodiment, the number of the second lamination 201b is one, and the number of the fifth lamination 201e is one, so that the coolant can flow along the preset path, and the number of the third laminations 201c can be increased appropriately. However, the present disclosure is not limited thereto.

[0063] In an embodiment, the first lamination 201a has the same structure as the second lamination 201b, and the first lamination 201a is offset from the second lamination 201b by a predetermined angle in a circumferential direction of the stator core 20. In this way, the types of the laminations 201 can be reduced, and the die costs for the laminations 201 can be saved.

[0064] In the embodiments shown in FIG. 5 to FIG. 9, each lamination 201 is provided with a protrusion 2010 protruding in the radial direction, and the protrusion 2010 may be provided with a connection through-hole. The protrusions 2010 of the laminations 201 are aligned with each other, the connection through-holes of the protrusions 2010 are configured for a fastener such as a bolt to pass through, so that the stator core 20 is connected to the motor housing 10 by the fastener. A plurality of protrusions 2010 may be provided for each lamination 201, corresponding protrusions 2010 of the laminations 201 are aligned with each other, and the stator core 20 is connected to the motor housing 10 by a plurality of fasteners.

[0065] In other embodiments, the stator core 20 may be connected to the motor housing 10 by means of shrink fit. The laminations 201 may be bonded or welded to each other. In this embodiment, the laminations 201 are fixed to one another by bonding.

[0066] Referring to FIG. 1 and FIG. 10, FIG. 10 is a schematic diagram of a motor housing cover 30.

[0067] The motor housing cover 30 is connected to the motor housing 10 to seal an opening of the motor housing 10. The motor housing cover 30 is detachably connected to the motor housing 10, so as to facilitate the maintenance of the stator core 20 and the stator winding (not shown). The motor housing cover 30 may be configured in the same shape as the stator core 20. The motor housing cover 30 is provided with a connection protrusion 31, which is aligned and connected with the protrusion 2010.

[0068] The above descriptions are merely some embodiments of the present disclosure, and are not intended to limit the present disclosure. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present disclosure shall fall within the scope of protection of the present disclosure.

Claims

1. An electric motor (100), comprising:a motor housing (10) comprising a coolant inlet (11); anda stator core (20) disposed inside the motor housing (10), wherein the stator core (20) comprises an annular stator yoke (21) and a plurality of stator teeth (22) distributed at intervals in a circumferential direction of the stator yoke (21), and the stator core (20) further comprises a first end face (23) on one axial end thereof and a second end face (24) on the other axial end thereof,wherein a first tooth-root cooling channel (25) is provided at a tooth-root (214) of at least one of the stator teeth (22) and extends in an axial direction of the stator core (20),the first tooth-root cooling channel (25) comprises a first inlet (250) and a first outlet (251), wherein the first inlet (250) is disposed between the first end face (23) and the second end face (24), and the first outlet (251) is disposed on the second end face (24),in the axial direction of the stator core (20), the coolant inlet (11) is closer to the first outlet (251) than the first inlet (250), anda first outer cooling channel (12) is defined between the motor housing (10) and the stator core (20), and is configured to communicate the coolant inlet (11) with the first inlet (250).

2. The electric motor (100) according to claim 1, whereina second tooth-root cooling channel (26) is provided at a tooth-root (214) of at least one of the stator teeth (22) and extends in the axial direction of the stator core (20),the second tooth-root cooling channel (26) comprises a second inlet (260) and a second outlet (261), wherein the second inlet (260) is disposed between the first end face (23) and the second end face (24), and the second outlet (261) is disposed on the first end face (23),in the axial direction of the stator core (20), the coolant inlet (11) is closer to the second outlet (261) than the second inlet (260), anda second outer cooling channel (13) is further defined between the motor housing (10) and the stator core (20), and is configured to communicate the coolant inlet (11) with the second inlet (260).

3. The electric motor (100) according to claim 2, whereinthe stator core (20) comprises a plurality of laminations (201) stacked in the axial direction, wherein each of the laminations (201) comprises an annular yoke portion (2011) and a plurality of tooth portions (2012) distributed at intervals in a circumferential direction of the yoke portion (2011),the yoke portions (2011) of the plurality of laminations (201) are stacked to form the stator yoke (21), andthe tooth portions (2012) of the plurality of laminations (201) are stacked to form the stator teeth (22).

4. The electric motor (100) according to claim 3, whereinthe plurality of laminations (201) comprise a first lamination (201a) located at the one axial end of the stator core (20), a second lamination (201b) located at the other axial end of the stator core (20), a plurality of third laminations (201c) located between the first lamination (201a) and the second lamination (201b), and a fourth lamination (201d) located between the first lamination (201a) and the plurality of third laminations (201c),the first inlet (250) is provided on the fourth lamination (201d), and the first outlet (251) is provided on the second lamination (201b),for each of the third laminations (201c), a first hole (2014) is provided at a tooth-root of at least one tooth portion (2012), corresponding first holes (2014) of the plurality of third laminations (201c) are coaxially arranged to form the first tooth-root cooling channel (25), and the first lamination (201a) blocks the first holes (2014).

5. The electric motor (100) according to claim 4, wherein the first inlet (250) is a first notch (2015) extending in a radial direction of the fourth lamination (201d).

6. The electric motor (100) according to claim 5, wherein the first notch (2015) has an opening size that gradually decreases from outside to inside, wherein an end of the first notch (2015) with a larger opening is in communication with the first outer cooling channel (12), and an end of the first notch (2015) with a smaller opening is in communication with the corresponding first holes (2014) of the third laminations (201c).

7. The electric motor (100) according to any one of claims 4 to 6, whereinthe plurality of laminations (201) further comprise a fifth lamination (201e) located between the second lamination (201b) and the plurality of third laminations (201c),the second inlet (260) is provided on the fifth lamination (201e), and the second outlet (261) is provided on the first lamination (201a),for each of the third laminations (201c), a second hole (2016) is provided at a tooth-root of at least one tooth portion (2012), corresponding second holes (2016) of the plurality of third laminations (201c) are coaxially arranged to form the second tooth-root cooling channel (26), and the second lamination (201b) blocks the second holes (2016), andthe second hole (2016) is arranged alternately with the first hole (2014).

8. The electric motor (100) according to claim 7, wherein the second inlet (260) is a second notch (2017) extending in a radial direction of the fifth lamination (201e).

9. The electric motor (100) according to claim 8, wherein the second notch (2017) has an opening size that gradually decreases from outside to inside, wherein an end of the second notch (2017) with a larger opening is in communication with the second outer cooling channel (13), and an end of the second notch (2017) with a smaller opening is in communication with the corresponding second holes (2016) of the third laminations (201c).

10. The electric motor (100) according to any one of claims 7 to 9, wherein the number of the third laminations (201c) is greater than that of each of the first lamination (201a), the second lamination (201b), the fourth lamination (201d), and the fifth lamination (201e).

11. The electric motor (100) according to claim 10, wherein the number of the first lamination (201a) is one, the number of the second lamination (201b) is one, the number of the fourth lamination (201d) is one, and the number of the fifth lamination (201e) is one.

12. The electric motor (100) according to any one of claims 3 to 11, whereinthe plurality of laminations (201) are fixed to one another by bonding.

13. The electric motor (100) according to any one of claims 4 to 11, whereinthe first lamination (201a) has the same structure as the second lamination (201b).

14. The electric motor (100) according to any one of claims 1 to 13, wherein the stator core (20) is connected to the motor housing (10) by a fastener.

15. The electric motor (100) according to any one of claims 1 to 14, further comprising:a motor housing cover (30) detachably connected to the motor housing (10) and configured to seal the motor housing (10).

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