Motor stator, flat wire motor, power assembly and vehicle

Abstract

The utility model discloses a motor stator, a flat wire motor, a power assembly and a vehicle. The motor stator comprises a stator iron core and a flat wire winding, the stator iron core surrounds the axis of the stator iron core, 72 stator grooves are evenly formed in the stator iron core in the circumferential direction of the stator iron core, and each stator groove penetrates through the two opposite ends of the stator iron core along the axis and is divided into an even number of groove layers in the radial direction of the stator iron core. The flat wire winding comprises three-phase windings, the three-phase windings are sequentially and periodically wound in the stator slots around the axis, and the stator slots occupied by each phase winding are rotationally symmetrical in the circumferential direction of the stator iron core; each phase winding comprises two parallel branches, and the two parallel branches of each phase winding are rotationally and symmetrically distributed in the circumferential direction of the stator iron core; any parallel branch comprises a plurality of hairpin coils with different pitches, each hairpin coil comprises a flat wire conductor, and a hairpin coil is arranged in each groove layer. According to the scheme, the counter electromotive force, resistance and inductance of the winding branches can be balanced, and circulating current between the winding branches is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of automobile body structure, and particularly relates to a motor stator, a flat wire motor, a power assembly and a vehicle. BACKGROUND

[0002] With low carbon, energy saving and intelligence becoming the core competitiveness of automobiles, new energy electric vehicles are in a stage of vigorous development. A driving motor is a power providing unit of a new energy vehicle. Thanks to the continuous increase in the sales of new energy vehicles, the demand for driving motors is increasing, and the requirements therefor are increasingly stringent. From the technical development path of the driving motor, the development trend of high power density and miniaturization of the motor makes it inevitable to adopt a flat wire winding motor. Compared with a round wire winding motor, the slot fill factor of the flat wire winding motor can be greatly improved, and the flat wire winding motor has the advantages of low loss, high efficiency, high power density, good heat dissipation performance and low noise.

[0003] For a flat wire winding structure with a plurality of parallel branch numbers, winding branch asymmetry often occurs, which will cause imbalance of counter electromotive force, resistance, inductance and other parameters of each winding branch, result in circulation between winding branches, increase additional copper loss of the motor, increase manufacturing cost, reduce motor efficiency and increase motor temperature rise. CONTENT OF THE INVENTION

[0004] The application provides a motor stator, a flat wire motor, a power assembly and a vehicle, which can balance counter electromotive force, resistance and inductance of winding branches and reduce circulation between winding branches.

[0005] To solve the above technical problems, one technical scheme adopted by the application is to provide a motor stator, which comprises a stator core and a flat wire winding. The stator core is uniformly arranged with 72 stator slots around an axis thereof and along a circumferential direction thereof. Each stator slot penetrates through opposite ends of the stator core along the axis and along a radial direction of the stator core. Each stator slot is divided into n slot layers, and n is an even number. The flat wire winding comprises three-phase windings, which are sequentially and periodically wound in the stator slots around the axis, and the stator slots occupied by each phase winding are rotationally symmetrical in the circumferential direction of the stator core. Each phase winding comprises two parallel branches, and the two parallel branches of each phase winding are rotationally symmetrically distributed in the circumferential direction of the stator core. Any parallel branch comprises a plurality of hairpin coils with different pitches, each hairpin coil comprises a flat wire conductor, and the hairpin coils are arranged in each slot layer.

[0006] Preferably, the pitches of every 6 hairpin coils in any parallel branch form a pitch combination, and each pitch combination comprises a plurality of different pitches.

[0007] Preferably, the plurality of different pitches comprises a plurality of 10, 11, 12, 13 and 14.

[0008] Preferably, in the wire-winding direction, the pitches in each of the pitch combinations are in sequence: 12, 14, 12, 10, 12 and 13; or in sequence: 12, 10, 12, 13, 12 and 11.

[0009] Preferably, the hairpin coil of any of the parallel branches traverses n slot layers in different stator slots.

[0010] Preferably, the voltage lead of any of the parallel branches is located at the 2nd slot layer, and the neutral point lead of any of the parallel branches is located at the nth slot layer.

[0011] To solve the above technical problems, another technical solution adopted by the present application is to provide a flat wire motor comprising the stator of any of the embodiments.

[0012] Preferably, the flat wire motor further comprises a rotor cooperating with the stator; wherein the pole number of the rotor is 6.

[0013] To solve the above technical problems, another technical solution adopted by the present application is to provide a power assembly comprising a reducer and the flat wire motor of any of the embodiments, the flat wire motor being in driving connection with the reducer.

[0014] To solve the above technical problems, another technical solution adopted by the present application is to provide a vehicle comprising the power assembly of any of the embodiments.

[0015] Differing from the prior art, the beneficial effects of the present application are as follows: the flat wire motor provided by the present application symmetrically arranges two parallel branches of each phase winding in the circumferential direction to reduce the imbalance of the back EMF, resistance, inductance and other parameters of each branch of the winding, thereby reducing the circulating current generated between each branch of the winding, reducing the additional copper loss of the motor, improving the efficiency of the motor and reducing the temperature rise of the motor. The hairpin coil is a U-shaped coil formed by bending the flat wire conductor, and the cross section of the flat wire conductor is rectangular. Compared with the round wire conductor, the flat wire conductor can greatly improve the slot fill factor under the premise of constant space, and the volume of the conductor filled in the stator slot 11 can be increased by 20%-30%, thereby generating a stronger magnetic field strength and increasing the power of the motor. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 is a structure diagram of an embodiment of a motor stator of a flat wire motor provided by the present application;

[0018] Figure 2 is a structure diagram of a stator core in the motor stator as shown in Figure 1 ;

[0019] Figure 3 is a structure diagram of an embodiment of a hairpin coil provided by the present application;

[0020] Figure 4 is a structure diagram of another embodiment of a hairpin coil provided by the present application;

[0021] Figure 5 is a winding mode of a parallel branch provided by the present application;

[0022] Figure 6 is a winding mode of another parallel branch provided by the present application. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0024] The present application provides a flat wire motor, which comprises a motor stator and a rotor cooperating with the motor stator. The rotor is arranged in a space formed by the inner wall of a stator core of the stator. In the embodiment, the pole number of the rotor is 6.

[0025] Referring to Figure 1 and Figure 2 , Figure 1 is a structure diagram of an embodiment of a motor stator of a flat wire motor provided by the present application, Figure 2 is a structure diagram of a stator core in the motor stator as shown in Figure 1 ;

[0026] The motor stator comprises a stator core 10 and a flat wire winding 20. The inner wall of the stator core 10 is uniformly arranged with a plurality of stator slots 11 around the axis and along the circumference thereof. In the embodiment, the number of the stator slots 11 is 72. Each stator slot 11 penetrates through the opposite ends of the stator core 10 along the axis, and each stator slot 11 is divided into n slot layers along the radial direction of the stator core 10, where n is an even number. The number of the slot layers can be 2, 4, 6, 8 or 10, etc.

[0027] The flat wire winding 20 comprises a three-phase winding, which comprises a U-phase winding, a V-phase winding and a W-phase winding, and the three-phase winding is periodically wound in the stator slot 11 along the axis in sequence, and the stator slot 11 occupied by each phase winding is rotationally symmetrical in the circumferential direction of the stator core 10, that is, the stator slot 11 occupied by the U-phase winding coincides with the stator slot 11 occupied by the V-phase winding after rotating by a certain angle along the circumferential direction, the stator slot 11 occupied by the V-phase winding coincides with the stator slot 11 occupied by the W-phase winding after rotating by the same angle along the circumferential direction, and the stator slot 11 occupied by the W-phase winding coincides with the stator slot 11 occupied by the U-phase winding after rotating by the same angle along the circumferential direction. Each phase winding comprises two parallel branches, and the two parallel branches of each phase winding are rotationally symmetrical in the circumferential direction of the stator core 10, that is, one parallel branch of each phase winding coincides with the other parallel branch after rotating by a certain angle along the circumferential direction.

[0028] The two parallel branches of each phase winding are rotationally symmetrical in the circumferential direction in the present application, so as to reduce the imbalance of the back-EMF, resistance, inductance and other parameters of each branch of the winding, thereby reducing the circulating current generated between each branch of the winding, reducing the additional copper loss of the motor, improving the efficiency of the motor, and reducing the temperature rise of the motor.

[0029] Each parallel branch comprises a plurality of hairpin coils 21 with different pitches, and each hairpin coil 21 comprises a flat wire conductor, and each slot layer is provided with a hairpin coil 21.

[0030] The hairpin coil 21 is a U-shaped coil formed by bending the flat wire conductor, and the cross section of the flat wire conductor is rectangular. Compared with a round wire conductor (i.e. a conductor with a circular cross section), the flat wire conductor can greatly improve the slot fill rate under the condition that the space remains unchanged, the volume of the conductor filled in the stator slot 11 can be increased by 20%-30%, and a stronger magnetic field strength is generated, thereby increasing the power of the motor.

[0031] Specifically, the hairpin coil 21 comprises a first leg 211 and a second leg 212 arranged at intervals, a connecting segment 213 connected between one end of the first leg 211 and one end of the second leg 212, a first bending segment 214 connected to one end of the first leg 211 away from the connecting segment 213, a first welding segment 216 connected to one end of the first bending segment 214 away from the first leg 211, a second bending segment 215 connected to one end of the second leg 212 away from the connecting segment 213, and a second welding segment 217 connected to one end of the second bending segment 215 away from the second leg 212. Before winding, the first bending segment 214 and the first welding segment 216 of the hairpin coil 21 are arranged in line with the first leg 211, and the second bending segment 215 and the second welding segment 217 are arranged in line with the second leg 212. The first leg 211 and the second leg 212 of the hairpin coil 21 are inserted into two stator slots 11 respectively, and the first bending segment 214, the first welding segment 216, the second bending segment 215 and the second welding segment 217 are exposed outside the stator slots 11. Then, the first bending segment 214 and the second bending segment 215 are bent, and two adjacent hairpin coils 21 are welded, so that a plurality of sequentially connected hairpin coils 21 form a complete parallel branch winding. In some embodiments, the first bending segment 214 connected to one end of the first welding segment 216 and the second bending segment 215 connected to one end of the second welding segment 217 extend in directions away from each other after being bent and formed, as shown in FIG. 8. In other embodiments, the first bending segment 214 connected to one end of the first welding segment 216 and the second bending segment 215 connected to one end of the second welding segment 217 extend in the same direction after being bent and formed, as shown in FIG. 9. Figure 3 Figure 4 The number of stator slots 11 spaced apart by the two stator slots 11 into which the first leg 211 and the second leg 212 of the hairpin coil 21 are inserted is the pitch of the hairpin coil 21.

[0032] The embodiment changes the pitch of the hairpin coil 21 in at least one parallel branch to change the winding mode of the flat wire winding 20, so as to further reduce the circulating current generated between the parallel branches.

[0033] ​Optionally, the pitch of every 6 hairpin coils 21 in any parallel branch is a pitch combination, and each pitch combination includes a plurality of different pitches. In the embodiment, the pitch corresponding to each hairpin coil 21 in each parallel branch of the winding has a certain rule, wherein the pitch corresponding to every 6 continuous hairpin coils 21 is a pitch combination, for example, the 6 pitches corresponding to the 1st-6th hairpin coils 21 form a pitch combination, and the 6 pitches corresponding to the 7th-12th hairpin coils 21 are the same as the 6 pitches corresponding to the 1st-6th hairpin coils 21, respectively, the 6 pitches corresponding to the 13th-18th hairpin coils 21 are the same as the 6 pitches corresponding to the 1st-6th hairpin coils 21, respectively, and so on until the hairpin coils 21 of the parallel branch are wound completely.

[0034] Optionally, the plurality of different pitches include 10, 11, 12, 13 and 14.

[0035] Optionally, in the winding direction, the pitches in each pitch combination are in turn 12, 14, 12, 10, 12 and 13; or in turn 12, 10, 12, 13, 12 and 11.

[0036] Optionally, the voltage lead of any parallel branch is located at the 2nd slot layer, and the neutral point lead of any parallel branch is located at the nth slot layer.

[0037] Optionally, in the embodiment, each stator slot 11 is provided with n layers of hairpin coils 21 in the radial direction, that is, the first leg 211 or the second leg 212 of the hairpin coil 21 is arranged in each slot layer of the stator slot 11. The hairpin coils 21 of any parallel branch traverse n slot layers in different stator slots 11, which can eliminate the potential difference caused by the different radial positions of the first leg 211 or the second leg 212 of the hairpin coil 21.

[0038] Optionally, the winding mode of the three-phase winding can be wave winding or lap winding.

[0039] Specifically, the motor of the embodiment has 72 stator slots 11, 6 rotor pole numbers, and has 6 slot layers. The positions passed by the parallel branches are shown by the number (a, m), wherein a is the number of the stator slot 11, and m is the number of the slot layer, that is, in the embodiment, a is a positive integer, and a≤72, and m is an even number, and m≤6.

[0040] The winding mode of the parallel branch of the present application is as follows: firstly, forward winding is performed, sequentially passing through (m, a)-(m-1, a+12)-(m, a+26)-(m-1, a+38)-(m, a+48)-(m-1, a+60)-(m-1, a+1), then reverse winding is performed, sequentially passing through (m, a+61)-(m-1, a+49)-(m, a+39)-(m+1, a+26)-(m, a+14)-(m, a+1), then returning to forward winding, sequentially passing through (m-1, a+13)-(m, a+27)-(m-1, a+39)-(m, a+51)-(m-1, a+63)-(m-1, a+2), then continuing reverse winding, sequentially passing through (m, a+62)-(m-1, a+49)-(m, a+37)-(m-1, a+24)-(m, a+12), at this time, the first slot layer and the second slot layer complete winding, after passing through (m+1, a+1), the third slot layer is entered, then forward winding is continued, passing through (m+1, a+12)…the third slot layer and the fourth slot layer, and the fifth slot layer and the sixth slot layer are wound according to the above winding sequence of the first slot layer and the second slot layer, until all the hairpin coils 21 of the parallel branch are wound, wherein, the pitch combination of all the hairpin coils 21 in every two slot layers is the same. It should be noted that the forward winding and the reverse winding herein refer to winding in the clockwise or counterclockwise direction along the circumference of the stator core.

[0041] Referring to Figure 5 , Figure 5is a winding method of a parallel branch of the application. The figure shows the stator slot 11 and the slot layer where one parallel branch of the U-phase winding passes through, wherein U1 is the position of the voltage lead-out line, i.e. the inlet position of the parallel branch; X1 is the position of the neutral point lead-out line, i.e. the outlet position of the parallel branch. The openings of all hairpin coils 21 shown by solid lines in the figure face the same direction, the openings of all hairpin coils 21 shown by dashed lines in the figure face the same direction, and the openings of the hairpin coils 21 shown by solid lines and the openings of the hairpin coils 21 shown by dashed lines face opposite directions. Specifically, when the parallel branch winds from the second layer of the first slot, i.e. m = 2, a = 1, it sequentially passes through the following positions: (2, 1)-(1, 13)-(2, 27)-(1, 39)-(2, 49)-(1, 61)-(1, 2)-(2, 62)-(1, 52)-(2, 40)-(1, 27)-(2, 15)-(2, 2)-(1, 14)-(2, 28)-(1, 40)-(2, 52)-(1, 64)-(1, 3)-(2, 63)-(1, 50)-(2, 38)-(1, 25)-(2, 13)-(3, 2)-(3, 13)-(4, 27)-(3, 39)-(4, 49)-(3, 61)-(3, 2)-(4, 62)-(3, 52)-(4, 40)-(3, 27)-(4, 15)-(4, 2)-(3, 14)-(4, 28)-(3, 40)-(4, 52)-(3, 64)-(3, 3)-(4, 63)-(3, 50)-(4, 38)-(3, 25)-(4, 13)-(5, 2)-(5, 13)-(6, 27)-(5, 39)-(6, 49)-(5, 61)-(5, 2)-(6, 62)-(5, 52)-(6, 40)-(5, 27)-(6, 15)-(6, 2)-(5, 14)-(6, 28)-(5, 40)-(6, 52)-(5, 64)-(5, 3)-(6, 63)-(5, 50)-(6, 38)-(5, 25)-(6, 13).

[0042] As can be seen from the winding rule of the parallel branch described above, along the winding direction, the pitch of every six hairpin coils 21 is one cycle, and the pitches are 12, 14, 12, 10, 12 and 13 in turn. The parallel branch traverses 6 slot layers. The voltage lead-out line is located in the 2nd slot layer, and the neutral point lead-out line is located in the 6th slot layer. The winding method of 6 slot layers is used in this embodiment, but the winding method is also applicable to the cases of 2, 4, 8 or 10 slot layers. In addition, in other embodiments, the positions of the voltage lead-out line and the neutral point lead-out line can also be other slot layers.

[0043] The winding mode of another parallel branch of the application is as follows: firstly, forward winding is performed, sequentially passing through (m, a+2)-(m-1, a+14)-(m, a+24)-(m-1, a+36)-(m, a+49)-(m-1, a+61)-(m-1, a), then reverse winding is performed, sequentially passing through (m, a+60)-(m-1, a+48)-(m, a+36)-(m-1, a+25)-(m, a+13)-(m, a+3), then returning to forward winding, sequentially passing through (m-1, a+15)-(m, a+25)-(m-1, a+37)-(m, a+50)-(m-1, a+62)-(m-1, a+3), then continuing reverse winding, sequentially passing through (m, a+63)-(m-1, a+50)-(m, a+38)-(m-1, a+27)-(m, a+15), at this time, the first slot layer and the second slot layer complete winding, after passing through (m+1, a+3), the third slot layer is entered, then forward winding is continued, passing through (m+1, a+14)…the third slot layer and the fourth slot layer, and the fifth slot layer and the sixth slot layer are wound according to the above winding sequence of the first slot layer and the second slot layer, until all the hairpin coils 21 of the parallel branch are wound, wherein the pitch combinations of all the hairpin coils 21 in every two slot layers are the same. It should be noted that the forward winding and the reverse winding herein refer to winding in the clockwise or counterclockwise direction along the circumference of the stator core 10.

[0044] Referring to Figure 6 , Figure 6is another winding method of a parallel branch of the application. The figure shows the stator slot 11 and the slot layer where one parallel branch of the U-phase winding passes through, where U2 is the position of the voltage lead-out line, i.e. the inlet position of the parallel branch; X2 is the position of the neutral point lead-out line, i.e. the outlet position of the parallel branch. Specifically, when the parallel branch is wound from the second layer of the third slot, i.e. m = 2, a = 1, it passes through the positions in the following order: (2, 3)-(1, 15)-(2, 25)-(1, 37)-(2, 50)-(1, 62)-(1, 1)-(2, 61)-(1, 49)-(2, 37)-(1, 26)-(2, 14)-(2, 4)-(1, 16)-(2, 26)-(1, 38)-(2, 51)-(1, 63)-(1, 4)-(2, 64)-(1, 51)-(2, 39)-(1, 28)-(2, 16)-(3, 4)-(3, 15)-(4, 25)-(3, 37)-(4, 50)-(3, 62)-(4, 1)-(4, 61)-(3, 49)-(4, 37)-(3, 26)-(4, 14)-(4, 4)-(3, 16)-(4, 26)-(3, 38)-(4, 51)-(3, 63)-(3, 4)-(4, 64)-(3, 51)-(4, 39)-(3, 28)-(4, 16)-(5, 15)-(6, 25)-(5, 37)-(6, 50)-(5, 62)-(5, 1)-(6, 61)-(5, 49)-(6, 37)-(5, 26)-(6, 14)-(6, 4)-(5, 16)-(6, 26)-(5, 38)-(6, 51)-(5, 63)-(5, 4)-(6, 64)-(5, 51)-(6, 39)-(5, 28)-(6, 16).

[0045] As can be seen from the winding rule of the parallel branch described above, along the winding direction, the pitch of every six hairpin coils 21 is one cycle, and the pitches are 12, 10, 12, 13, 12 and 11 in turn. The parallel branch traverses 6 slot layers. The voltage lead-out line is located in the 2nd slot layer, and the neutral point lead-out line is located in the 6th slot layer. This embodiment is a winding method for 6 slot layers, but the winding method is also applicable to 2, 4, 8 or 10 slot layers. In addition, in other embodiments, the positions of the voltage lead-out line and the neutral point lead-out line can also be other slot layers. The two winding methods described above are applied to two parallel branches of the same phase winding respectively, so that the circulating current between the two parallel branches is small.

[0046] Figure 5 and Figure 6Only the winding mode of two parallel branches of the U-phase winding is shown. As can be seen from the figure, the U-phase winding occupies the first to fourth, thirteenth to sixteenth, twenty-fifth to twenty-eighth, thirty-seventh to fortieth, forty-ninth to fifty-second, and sixty-first to sixty-fourth stator slots. Since the stator slots 11 occupied by each phase winding are rotationally symmetrical in the circumferential direction of the stator core 10, the winding modes of the V-phase winding and the W-phase winding are only different from that of the U-phase winding in the positions of the occupied stator slots, that is, the U-phase winding coincides with the V-phase winding after moving four stator slots in the circumferential direction, the V-phase winding occupies the fifth to eighth, seventeenth to twentieth, twenty-ninth to thirty-second, forty-first to forty-fourth, fifty-third to fifty-sixth, and sixty-fifth to sixty-eighth stator slots, the V-phase winding coincides with the W-phase winding after moving four stator slots in the circumferential direction, and the W-phase winding occupies the ninth to twelfth, twenty-first to twenty-fourth, thirty-third to thirty-sixth, forty-fifth to forty-eighth, fifty-seventh to sixtieth, and sixty-ninth to seventy-second stator slots.

[0047] The embodiment of the present application also provides a power assembly, which comprises a reducer and the flat wire motor. The flat wire motor and the reducer are in driving connection. Specifically, the driving shaft of the flat wire motor and the input shaft of the reducer are in driving connection through a transmission member such as a shaft coupling, so that driving force is output from the flat wire motor to the reducer.

[0048] The vehicle provided by the embodiment of the present application comprises the power assembly, and the power assembly is arranged in the vehicle and provides operating power for the vehicle. Specifically, in the embodiment, the vehicle can be a new energy vehicle driven by electric energy. The new energy vehicle can be a hybrid electric vehicle, a pure electric vehicle, a fuel cell electric vehicle, or a vehicle using a super capacitor, a flywheel battery, or a flywheel energy storage device as an energy source.

[0049] The above is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation based on the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. An electric machine stator, characterized in that, The electric machine stator comprises: a stator core, which is uniformly arranged with 72 stator slots around its axis and along its circumference, each of the stator slots penetrates through opposite ends of the stator core along the axis and is divided into n slot layers along the radial direction of the stator core, n being an even number; a flat wire winding, which comprises three-phase windings, the three-phase windings are sequentially and periodically wound in the stator slots around the axis, and the stator slots occupied by each phase winding are rotationally symmetrical in the circumferential direction of the stator core; wherein, each phase winding comprises 2 parallel branches, and the 2 parallel branches of each phase winding are rotationally symmetrical distributed in the circumferential direction of the stator core; any of the parallel branches comprises a plurality of hairpin coils with different pitches, each hairpin coil comprises a flat wire conductor, and the hairpin coils are arranged in each of the slot layers; the pitch of every 6 hairpin coils in any of the parallel branches is a pitch combination, each of the pitch combinations comprises a plurality of different pitches; along the winding direction, the pitches in each of the pitch combinations are sequentially 12, 14, 12, 10, 12 and 13; or sequentially 12, 10, 12, 13, 12 and 11.

2. The electric machine stator according to claim 1, wherein, the hairpin coils of any of the parallel branches traverse n slot layers in different stator slots.

3. The electric machine stator according to claim 1, wherein, the voltage lead of any of the parallel branches is located at the 2nd slot layer, and the neutral point lead of any of the parallel branches is located at the nth slot layer.

4. A flat wire motor characterized by The electric machine stator comprises:

5. The flat wire motor of claim 4, wherein a stator core, which is uniformly arranged with 72 stator slots around its axis and along its circumference, each of the stator slots penetrates through opposite ends of the stator core along the axis and is divided into n slot layers along the radial direction of the stator core, n being an even number; a flat wire winding, which comprises three-phase windings, the three-phase windings are sequentially and periodically wound in the stator slots around the axis, and the stator slots occupied by each phase winding are rotationally symmetrical in the circumferential direction of the stator core; wherein, 6. A powertrain characterized by, each phase winding comprises 2 parallel branches, and the 2 parallel branches of each phase winding are rotationally symmetrical distributed in the circumferential direction of the stator core; 7. A vehicle characterized by comprising: any of the parallel branches comprises a plurality of hairpin coils with different pitches, each hairpin coil comprises a flat wire conductor, and the hairpin coils are arranged in each of the slot layers; the pitch of every 6 hairpin coils in any of the parallel branches is a pitch combination, each of the pitch combinations comprises a plurality of different pitches; along the winding direction, the pitches in each of the pitch combinations are sequentially 12, 14, 12, 10, 12 and 13; or sequentially 12, 10, 12, 13, 12 and 11.

2. The electric machine stator according to claim 1, wherein, the hairpin coils of any of the parallel branches traverse n slot layers in different stator slots.

3. The electric machine stator according to claim 1, wherein, the voltage lead of any of the parallel branches is located at the 2nd slot layer, and the neutral point lead of any of the parallel branches is located at the nth slot layer. The electric machine stator comprises: a stator core, which is uniformly arranged with 72 stator slots around its axis and along its circumference, each of the stator slots penetrates through opposite ends of the stator core along the axis and is divided into n slot layers along the radial direction of the stator core, n being an even number; a flat wire winding, which comprises three-phase windings, the three-phase windings are sequentially and periodically wound in the stator slots around the axis, and the stator slots occupied by each phase winding are rotationally symmetrical in the circumferential direction of the stator core; wherein, each phase winding comprises 2 parallel branches, and the 2 parallel branches of each phase winding are rotationally symmetrical distributed in the circumferential direction of the stator core; any of the parallel branches comprises a plurality of hairpin coils with different pitches, each hairpin coil comprises a flat wire conductor, and the hairpin coils are arranged in each of the slot layers; the pitch of every 6 hairpin coils in any of the parallel branches is a pitch combination, each of the pitch combinations comprises a plurality of different pitches; along the winding direction, the pitches in each of the pitch combinations are sequentially 12, 14, 12, 10, 12 and 13; or sequentially 12, 10, 12, 13, 12 and 11.

2. The electric machine stator according to claim 1, wherein, the hairpin coils of any of the parallel branches traverse n slot layers in different stator slots.

3. The electric machine stator according to claim 1, wherein, the voltage lead of any of the parallel branches is located at the 2nd slot layer, and the neutral point lead of any of the parallel branches is located at the nth slot layer. The electric machine stator comprises: a stator core, which is uniformly arranged with 72 stator slots around its axis and along its circumference, each of the stator slots penetrates through opposite ends of the stator core along the axis and is divided into n slot layers along the radial direction of the stator core, n being an even number; a flat wire winding, which comprises three-phase windings, the three-phase windings are sequentially and periodically wound in the stator slots around the axis, and the stator slots occupied by each phase winding are rotationally symmetrical in the circumferential direction of the stator core; wherein, each phase winding comprises 2 parallel branches, and the 2 parallel branches of each phase winding are rotationally symmetrical distributed in the circumferential direction of the stator core; any of the parallel branches comprises a plurality of hairpin coils with different pitches, each hairpin coil comprises a flat wire conductor, and the hairpin coils are arranged in each of the slot layers; the pitch of every 6 hairpin coils in any of the parallel branches is a pitch combination, each of the pitch combinations comprises a plurality of different pitches; along the winding direction, the pitches in each of the pitch combinations are sequentially 12, 14, 12, 10, 12 and 13; or sequentially 12, 10, 12, 13, 12 and 11.

2. The electric machine stator according to claim 1, wherein, the hairpin coils of any of the parallel branches traverse n slot layers in different stator slots.

3. The electric machine stator according to claim 1, wherein, the voltage lead of any of the parallel branches is located at the 2nd slot layer, and the neutral point lead of any of the parallel branches is located at the nth slot layer. The electric machine stator comprises: a stator core, which is uniformly arranged with 72 stator slots around its axis and along its circumference, each of the stator slots penetrates through opposite ends of the stator core along the axis and is divided into n slot layers along the radial direction of the stator core, n being an even number; a flat wire winding, which comprises three-phase windings, the three-phase windings are sequentially and periodically wound in the stator slots around the axis, and the stator slots occupied by each phase winding are rotationally symmetrical in the circumferential direction of the stator core; wherein, each phase winding comprises 2 parallel branches, and the 2 parallel branches of each phase winding are rotationally symmetrical distributed in the circumferential direction of the stator core; any of the parallel branches comprises a plurality of hairpin coils with different pitches, each hairpin coil comprises a flat wire conductor, and the hairpin coils are arranged in each of the slot layers; the pitch of every 6 hairpin coils in any of the parallel branches is a pitch combination, each of the pitch combinations comprises a plurality of different pitches; along the winding direction, the pitches in each of the pitch combinations are sequentially 12, 14, 12, 10, 12 and 13; or sequentially 12, 10, 12, 13, 12 and 11.

2. The electric machine stator according to claim 1, wherein, the hairpin coils of any of the parallel branches traverse n slot layers in different stator slots.

3. The electric machine stator according to claim 1, wherein, the voltage lead of any of the parallel branches is located at the 2nd slot layer, and the neutral point lead of any of the parallel branches is located at the nth slot layer. The electric machine stator comprises: a stator core, which is uniformly arranged with 72 stator slots around its axis and along its circumference, each of the stator slots penetrates through opposite ends of the stator core along the axis and is divided into n slot layers along the radial direction of the stator core, n being an even number; a flat wire winding, which comprises three-phase windings, the three-phase windings are sequentially and periodically wound in the stator slots around the axis, and the stator slots occupied by each phase winding are rotationally symmetrical in the circumferential direction of the stator core; wherein, each phase winding comprises 2

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