Stator assembly, motor and electric vehicle

Abstract

The present application discloses a stator assembly, a motor and an electric vehicle. The stator assembly includes: a stator core and a winding. The stator core includes an outer wall and an inner wall arranged back to back, the inner wall is provided with a plurality of stator slots, and the plurality of stator slots are arranged at intervals from each other along the circumference of the stator core; along the radial direction of the stator core, each stator slot is divided into a plurality of slot layers; wherein, every three adjacent stator slots serve as a stator slot group. The winding includes a three-phase winding, and the three-phase winding is alternately wound around different stator slot groups along the circumference of the stator core. Each phase winding includes three branches connected in parallel, and the three branches are rotationally symmetrical around the axial direction of the stator core. Based on the stator assembly, the three branches of the same-phase winding can be brought into a state of potential balance to avoid the generation of circulating current between the branches of the same-phase winding as much as possible.

Description

Technical Field

[0001] The present application relates to the field of motor technology, and in particular to a stator assembly, a motor and an electric vehicle. Background Art

[0002] Electric vehicles place high demands on motors. With the advancement of flat wire technology, electric vehicle motors are increasingly using flat wire for their windings. This type of winding efficiently utilizes the space in the motor's stator slots, meeting the performance requirements of electric vehicles.

[0003] However, due to the complex structure of the windings in the motor, potential imbalance is likely to occur between the branches of the same phase, resulting in the formation of circulating currents between the branches, affecting the efficiency and temperature rise of the motor. Summary of the Invention

[0004] The purpose of the present application is to provide a stator assembly, a motor and an electric vehicle to solve the problem that the motor is prone to forming circulating currents.

[0005] To address the above-mentioned technical problems, the present application provides a stator assembly comprising: a stator core and a winding. The stator core comprises an outer wall and an inner wall disposed in opposite directions. The inner wall is provided with a plurality of stator slots spaced apart from each other along the circumference of the stator core. Each stator slot is divided into multiple slot layers along the radial direction of the stator core, wherein three adjacent stator slots constitute a stator slot group. The winding comprises a three-phase winding, which is alternately wound around different stator slot groups along the circumference of the stator core. Each phase of the winding comprises three parallel branches, and the three branches are rotationally symmetric about the axial direction of the stator core. Therefore, under power supply conditions, in each slot layer within the same stator slot, the three branches of the same-phase winding have the same magnetic field distribution; accordingly, the potentials of the three branches are balanced. Due to this potential balance, circulating currents are prevented between the three branches, thereby improving the efficiency of the motor and reducing the temperature rise of the motor. It should be understood that multiple slot layers within the same stator slot group all house conductors of the same-phase winding, thereby eliminating the interphase insulation paper originally required between conductors of different-phase windings in the same slot. While maintaining the volume of the stator assembly, the windings can occupy more space within the stator slots, thereby increasing the stator assembly's copper fill rate and enabling the corresponding motor to have better performance (e.g., higher motor efficiency, lower temperature rise, etc.). While maintaining the motor's performance, the stator assembly can be more compact and lighter, facilitating the spatial arrangement of the corresponding motor in an electric vehicle while reducing the overall vehicle weight and cost.

[0006] In some embodiments, each branch comprises a plurality of U-shaped flat wires connected in series, each having a hairpin end, with a welded end formed between two adjacent U-shaped flat wires; the hairpin end and the welded end are located on different sides of the stator core. The incoming wire of each branch is introduced into the first slot layer of the corresponding stator slot, and the outgoing wire of each branch is led out from the first slot layer of another corresponding stator slot; the first slot layer is the slot layer closest to the outer wall of the stator core, or the first slot layer is the slot layer closest to the inner wall of the stator core. This facilitates the arrangement and connection of the incoming and outgoing wires.

[0007] In some embodiments, in each branch, both the ends of the incoming wire and the ends of the outgoing wire are hairpin ends; alternatively, both the ends of the incoming wire and the ends of the outgoing wire are welded ends. This facilitates the insertion and welding of the winding 200, thereby reducing the difficulty of manufacturing the stator assembly and improving its production efficiency.

[0008] In some embodiments, the U-shaped flat wire includes two pins, with the hairpin end positioned between the two pins. The two pins are respectively inserted into the odd-numbered slot layers and the even-numbered slot layers of different stator slot groups. The ends of the pins inserted into the odd-numbered slot layers are bent at the same angle toward a first circumferential direction; the ends of the pins inserted into the even-numbered slot layers are bent at the same angle toward a second circumferential direction; the first circumferential direction and the second circumferential direction are opposite. This facilitates processing equipment for bending and welding the pins of the U-shaped flat wire, reducing the difficulty of winding production.

[0009] In some embodiments, in each stator slot group, the three branches of the corresponding in-phase winding are wound around the same number of slot layers; each branch is wound around the odd-numbered slot layers of one stator slot and around the even-numbered slot layers of another stator slot. This facilitates orderly winding of the branches and ensures rotational symmetry between the branches.

[0010] In some embodiments, the span of the hairpin end of each branch is a combination of 7, 10, and 10, and the span of the welding end of each branch is 9; wherein the span is the number of stator slots spanned by the hairpin end or the welding end.

[0011] In some embodiments, the span of the hairpin end of each branch is a combination of 8, 8, and 11, and the span of the welding end of each branch is 9; wherein the span is the number of stator slots spanned by the hairpin end or the welding end.

[0012] In some embodiments, in the three-phase winding, branches of different phase windings are rotationally symmetric around the axial direction of the stator core.

[0013] In some embodiments, the rotational symmetry angle is 120° or 240°. It should be understood that rotational symmetry can also be understood as meaning that the three branches of the in-phase winding are rotationally symmetrical with the central axis of the stator core as the rotation axis. When the stator assembly is applied to a motor, the central axis can also refer to the rotor of the motor's rotor assembly.

[0014] In some embodiments, a branch of the same-phase winding is shifted by a certain number of stator slot groups to overlap with other branches of the same-phase winding.

[0015] The present application further provides a motor, comprising: a rotor assembly and the stator assembly described in the above embodiments. The rotor assembly is disposed inside the stator assembly.

[0016] The present application also provides an electric vehicle, comprising the motor in each of the above embodiments, wherein the motor can be applied to a powertrain of the electric vehicle.

[0017] Through the winding structure of the stator assembly, the present application can make the three branches of the same-phase winding reach a state of potential balance, so as to avoid the generation of circulating current between the branches of the same-phase winding as much as possible, thereby improving the efficiency of the motor and making the motor have a lower temperature rise. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a three-dimensional diagram of a stator assembly according to an embodiment of the present application.

[0019] Figure 2 It is a three-dimensional diagram of a stator core according to an embodiment of the present application.

[0020] Figure 3 It is a front view of a stator assembly according to an embodiment of the present application.

[0021] Figure 4 yes Figure 3 Cross-sectional view of the stator assembly along AA.

[0022] Figure 5 yes Figure 4 A partial enlarged schematic diagram of the stator assembly in area I.

[0023] Figure 6 FIG. 1 is a schematic diagram of a U-shaped flat wire according to an embodiment of the present application.

[0024] Figure 7 Schematic diagram of two connected U-shaped flat wires according to an embodiment of the present application.

[0025] Figure 8 This is a winding expansion diagram of the first U-phase branch of an embodiment of the present application.

[0026] Figure 9This is a winding expansion diagram of the second U-phase branch of an embodiment of the present application.

[0027] Figure 10 This is a winding expansion diagram of the third U-phase branch of an embodiment of the present application.

[0028] Figure 11 1 is a winding expansion diagram of the U, V, and W three-phase windings of an embodiment of the present application.

[0029] Figure 12 This is a circuit connection diagram of the U, V, and W three-phase windings of an embodiment of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present application.

[0031] Each embodiment of the present application provides a motor, comprising a stator assembly and a rotor assembly, wherein the rotor assembly is mounted within the stator assembly. When powered, the windings of the stator assembly generate a rotating magnetic field, driving the rotor assembly to rotate relative to the stator assembly.

[0032] In some embodiments, the motor can be used in the powertrain of an electric vehicle (also known as a new energy vehicle).

[0033] Please refer to the Figure 1 、 Figure 2 and Figure 3 The stator assembly 10 provided in an embodiment of the present application includes: a stator core 100 and a winding 200. The stator core 100 is generally cylindrical in shape so as to accommodate the rotor assembly in the stator core 100. The cylindrical stator core 100 includes an inner wall 102 and an outer wall 104 arranged back to back; wherein, relative to the outer wall 104, the inner wall 102 of the stator core 100 is closer to the rotor assembly. The inner wall 102 is provided with a plurality of stator slots 110, and the plurality of stator slots 110 are spaced apart from each other and arranged along the circumferential direction of the stator core 100. A single stator slot 110 can be arranged along the axial direction of the stator core 100. The winding 200 is accommodated in the stator slot 110. When the winding 200 is energized, a rotating magnetic field is generated.

[0034] Please refer to the Figure 4 and Figure 5 In some embodiments, each stator slot 110 is divided into six slot layers along the radial direction of the stator core 100. Each slot layer can accommodate one conductor, meaning that each stator slot 110 can accommodate six conductors. It should be understood that the relationship between stator slots and slot layers can be analogized to the relationship between the abscissa and ordinate in a rectangular coordinate system. The position of the corresponding conductor can be determined based on the number of the stator slots and the number of the slot layers.

[0035] In some embodiments, the stator assembly 10 is illustrated as having 54 stator slots 110; that is, the motor is a 54-slot motor, but the present invention is not limited thereto. It should be understood that in other embodiments, based on the conductor arrangement data diagrams and corresponding winding expansion diagrams shown in Tables 1 to 7 below, the number of stator slots 110 in the stator assembly 10 may be 36, 72, or 90, etc., without limitation.

[0036] In some embodiments, the winding includes a U-phase winding, a V-phase winding, and a W-phase winding. Figure 4 and Figure 5 For this three-phase winding, in the stator core 100, every three adjacent stator slots 110 form a stator slot group 110a. For example, the first to third stator slots 110 form a stator slot group 110a, the fourth to sixth stator slots 110 form a stator slot group 110a, the seventh to ninth stator slots 110 form a stator slot group 110a, and so on. Along the circumference of the stator core, the U-phase winding, the V-phase winding, and the W-phase winding are alternately wound around different stator slot groups 110a.

[0037] Taking a 54-slot motor as an example, the 54-slot motor comprises three stator slots 110 as a stator slot group 110a, thus comprising a total of 18 stator slot groups 110a. Corresponding to the U, V, and W three-phase windings, the U, V, and W three-phase windings are alternately wound around six stator slot groups 110a, respectively.

[0038] In some embodiments, the U-phase winding, the V-phase winding, and the W-phase winding each include three branches connected in parallel. Each branch includes a plurality of U-shaped flat wires connected in series. Each U-shaped flat wire has a hairpin end and a pin. The pins are welded between two adjacent U-shaped flat wires to form a welding end of the corresponding branch. The hairpin end and the welding end are located on different sides of the stator core. From the overall perspective, the shape of each branch after unfolding is roughly wavy. The crest is the hairpin end, and the trough is the welding end; or, the crest is the welding end, and the trough is the hairpin end. Between the crest and the trough is the pin of the U-shaped flat wire, which serves as a conductor connected between the hairpin end and the welding end.

[0039] In some embodiments, the U-phase winding includes a first U-phase branch, a second U-phase branch, and a third U-phase branch; the V-phase winding includes a first V-phase branch, a second V-phase branch, and a third V-phase branch; and the W-phase winding includes a first W-phase branch, a second W-phase branch, and a third W-phase branch. It should be understood that the stator assembly 10 and the motor of each embodiment are primarily described using the three branches of the U-phase winding as an example. The windings 200 of other phases can be understood based on the structure of the U-phase winding and are not described in detail.

[0040] Please refer to Figure 6In some embodiments, each U-shaped flat wire 210 includes a hairpin end 220, a first pin 212, and a second pin 214; the hairpin end 220 is located between the first pin 212 and the second pin 214. It should be understood that when assembling the U-shaped flat wire 210 into the stator slots 110 of the stator core 100 to form a specific branch, the first pin 212 of the U-shaped flat wire 210 of the specific branch is inserted into the odd-numbered slot layer of a certain stator slot group, while the second pin 214 is inserted into the even-numbered slot layer of another stator slot group. That is, the two pins of the same U-shaped flat wire 210 are located in different stator slot groups and inserted into different slot layers. Overall, for each stator slot group, the three branches of the corresponding winding are wound around the odd-numbered slot layers of one stator slot group and around the even-numbered slot layers of another stator slot group, so that each branch is wound in an orderly manner.

[0041] In some other embodiments, the first pin 212 of the U-shaped flat wire 210 may be inserted into an even-numbered slot layer of a certain stator slot group 110 a ; and the second pin 214 may be inserted into an odd-numbered slot layer of another stator slot group 110 a .

[0042] In some embodiments, the hairpin end 220 of the U-shaped flat wire 210 is located on one side of the stator core 100, and the two pins (212, 214) of the U-shaped flat wire 210 are inserted into the stator slot 110, and the two pins (212, 214) at least partially pass through the stator slot 110 and extend to the other side of the stator core 100 to facilitate the insertion and welding of the winding 200.

[0043] Please refer to the Figure 6 and Figure 7 In some embodiments, the first pin 212 of one U-shaped flat wire 210 is welded to the second pin 214 of another U-shaped flat wire 210 to form a welded end 230. The second pin 214 of the U-shaped flat wire 210 is welded to the first pin 212 of yet another U-shaped flat wire 210 to form another welded end 230. In this manner, multiple U-shaped flat wires 210 are welded together and extend along the circumference of the stator core 100, winding around corresponding stator slots to form a branch circuit.

[0044] Please refer to Figure 1 、 Figure 6 and Figure 7In some embodiments, based on the stator assembly 10 provided herein, the pins located in the 1st, 3rd, and 5th slot layers are bent in a first circumferential direction g, while the pins located in the 2nd, 4th, and 6th slot layers are bent in a second circumferential direction h; wherein the first circumferential direction g and the second circumferential direction h are opposite. For example, the pins located in the 1st, 3rd, and 5th slot layers are bent counterclockwise, while the pins located in the 2nd, 4th, and 6th slot layers are bent clockwise. Based on this, the manufacturing process of the stator assembly 10 can be simplified, facilitating the welding of the U-shaped flat wire 210 to form the branch welding end 230.

[0045] Table 1 is a table of conductor arrangement data for the U, V, and W three-phase windings according to an embodiment of the present application.

[0046] Table 1

[0047]

[0048]

[0049] Please refer to the Figure 4 、 Figure 5 As shown in Table 1, in some embodiments, the U-phase winding, V-phase winding, and W-phase winding are each wound around different stator slot groups 110a. Taking a 54-slot motor as an example, the first through third stator slots are referred to as the first stator slot group, the fourth through sixth stator slots are referred to as the second stator slot group, the seventh through ninth stator slots are referred to as the third stator slot group, and so on. For these stator slot groups, the U-phase winding is, for example, wound around the first, fourth, seventh, tenth, thirteenth, and sixteenth stator slot groups; the V-phase winding is, for example, wound around the second, fifth, eighth, eleventh, fourteenth, and seventeenth stator slot groups 110a; and the W-phase winding is, for example, wound around the third, sixth, ninth, twelfth, fifteenth, and eighteenth stator slot groups 110a. It should be understood that, based on the order of the stator slot groups 110a, the U, V, and W three-phase windings 200 are regularly alternating. In the above example, the phase sequence of the windings 200 installed in the plurality of stator slot groups 110 a is U, V, W, but this is not a limitation. In other embodiments, the phase sequence of the windings 200 installed in each stator slot group 110 a may be other, and this is not a limitation. For example, the phase sequence of the windings 200 may be V, U, W, or W, V, U, etc.

[0050] In some other embodiments, the U-phase winding may also be wound around the 2nd, 5th, 8th, 11th, 14th and 17th stator slot groups 110a; and the V and W two-phase windings 200 are adaptively wound around other stator slot groups 110a, without limitation.

[0051] Based on this, multiple slot layers within the same stator slot group 110a all accommodate conductors of the same-phase winding. This eliminates the need for interphase insulation paper between conductors of different-phase windings in the same slot, reducing motor insulation costs and eases wiring insertion, while also improving the motor's copper fill rate.

[0052] Table 2 is a table of conductor arrangement data for the first U-phase branch; Table 3 is a table of conductor arrangement data for the second U-phase branch; and Table 4 is a table of conductor arrangement data for the third U-phase branch.

[0053] Table 2

[0054]

[0055]

[0056] Table 3

[0057]

[0058]

[0059] Table 4

[0060]

[0061]

[0062] Please refer to Tables 2 to 4, and Figures 6 and 7 When the U-phase current is positive, along the current flow direction, U+ represents the U-phase current flowing from the hairpin terminal 220 to the welding terminal 230, and U- represents the U-phase current flowing from the welding terminal 230 to the hairpin terminal 220. When the V-phase current is positive, along the current flow direction, V+ represents the V-phase current flowing from the hairpin terminal 220 to the welding terminal 230, and V- represents the V-phase current flowing from the welding terminal 230 to the hairpin terminal 220. When the W-phase current is positive, along the current flow direction, W+ represents the W-phase current flowing from the hairpin terminal 220 to the welding terminal 230, and W- represents the W-phase current flowing from the welding terminal 230 to the hairpin terminal 220.

[0063] Taking the U-phase winding as an example, it can be seen from Tables 2 to 4 that in the three branches of the U-phase winding, the positions of U+ and U- of the three branches are rotationally symmetrical and the number is the same. For example: along the direction of increasing stator slot number, combined with Tables 2 and 3, it can be seen that the first U-phase branch can overlap with the second U-phase branch after moving 18 stator slots (or 6 stator slot groups); that is, the first U-phase branch and the second U-phase branch are rotationally symmetrical. Combined with Tables 2 and 4, it can be seen that the first U-phase branch can overlap with the third U-phase branch after moving 36 stator slots (or 12 stator slot groups); that is, the first U-phase branch and the third U-phase branch are rotationally symmetrical. Combined with Tables 1 to 4, it can be seen that the three branches of the U-phase winding are just wound around the corresponding 6 stator slot groups, and the 6 stator slot groups are also symmetrically distributed on the stator core.

[0064] Each U-phase branch has the same number of U+ and U- pins in slot layers 1 through 6. For example, in the 54-slot motor shown in the example, limited to slot layer 1, each of the three U-phase branches has three U+ and three U- pins. Furthermore, limited to slot layer 1 of each stator slot group, each of the three U-phase branches has one U+ and one U- pin. Within any stator slot where the U-phase winding is wound, each of the three U-phase branches has two U+ and two U- pins, each with two pins. The total number of U+ and U- pins in the three branches is exactly equal to the number of stator slot layers (i.e., six).

[0065] In some embodiments, the three branches of the U-phase winding are rotationally symmetrical along the circumference of the stator core 100. That is, after rotating a certain angle along the circumference of the stator core 100, the first U-phase branch can overlap with the second U-phase branch or the third U-phase branch. It should be understood that this overlap assumes that only the first U-phase branch rotates along the circumference of the stator core 100, while the second and third U-phase branches do not rotate.

[0066] In some embodiments, similar to the relationship between the three branches of the U-phase winding, the three branches of the V-phase winding are rotationally symmetrical along the circumference of the stator core 100. That is, after rotating the stator core 100 by a certain angle, the first V-phase branch can overlap with the second V-phase branch or the third V-phase branch. It should be understood that this overlap assumes that only the first V-phase branch rotates along the circumference of the stator core 100, while the second and third V-phase branches do not rotate.

[0067] In some embodiments, similar to the relationship between the three branches of the U-phase winding, the three branches of the W-phase winding are rotationally symmetrical along the circumference of the stator core 100. That is, after rotating a certain angle along the circumference of the stator core 100, the first W-phase branch can overlap with the second W-phase branch or the third W-phase branch. It should be understood that this overlap assumes that only the first W-phase branch rotates along the circumference of the stator core 100, while the second and third W-phase branches do not rotate.

[0068] It should be understood that the rotational symmetry can also be understood as the rotation axis of the three branches of the same-phase winding being rotationally symmetrical with the central axis of the stator core 100 as the rotation axis. When the stator assembly 10 is applied to a motor, the central axis can also refer to the rotor of the rotor assembly.

[0069] To this end, the three branches corresponding to each phase winding 200 are rotationally symmetrical, with U-shaped flat wires arranged in slot layers 1 through 6. Under power conditions, the three branches have identical magnetic field distributions across the same stator slot, resulting in balanced potentials across the three branches. This potential balance prevents circulating currents between the three branches, improving motor efficiency and reducing temperature rise.

[0070] In the actual stator assembly 10, based on some slight differences in the specifications and sizes of each U-shaped flat wire 210, there may be a particularly small potential difference (for example, a few millivolts) between the three branches of the same-phase winding, but the impact of this potential difference on the branches can be ignored, and the three branches should be understood to be in a state of potential balance.

[0071] In some embodiments, the first U-phase branch of the U-phase winding can overlap with the second U-phase branch or the third U-phase branch by rotating 120° or 240° along the circumference of the stator core 100. It should be understood that since the stator slots 110 are arranged along the circumference of the stator core 100, this rotational symmetry or overlap can also be equivalent to a branch of the same-phase winding being moved by a certain number of stator slot groups and overlapping with other branches of the same-phase winding. Taking a 54-slot motor as an example, the first U-phase branch can overlap with the second U-phase branch or the third U-phase branch after moving 6 stator slot groups (or moving 18 stator slots).

[0072] In some embodiments, in the three-phase U, V, and W windings, the branches of the windings of different phases are also rotationally symmetrical; for example, the U-phase branch is rotationally symmetrical with the V-phase branch; or, the U-phase branch is rotationally symmetrical with the W-phase branch; or, the V-phase branch is rotationally symmetrical with the W-phase branch. Based on this, the rotationally symmetrical windings not only eliminate problems such as circulating currents, but also facilitate the design of the winding structure and the winding of the U-shaped flat wire around the stator core.

[0073] Please refer to the Figure 5, and Tables 1 to 4, based on the stator assembly provided in the embodiment of the present application, with 9 adjacent stator slots as the minimum repeating unit, the 54-slot motor has a total of 6 minimum repeating units. For example, in the three stator slot groups from the 1st stator slot to the 9th stator slot, the U-phase winding occupies 18 slot layers of the 1st to 3rd stator slots, the V-phase winding occupies 18 slot layers of the 4th to 6th stator slots, and the U-phase winding occupies 18 slot layers of the 7th to 9th stator slots. As a result, the windings of each phase are spaced apart and placed in different stator slot groups; accordingly, for the 6 conductors of the same phase in each stator slot, no interphase insulation paper is required for further isolation between each other.

[0074] It should be understood that because the stator assembly 10 and motor of the present application eliminate the interphase insulation paper between the slot layers of the same stator slot 110, the U-shaped flat wire 210 of the motor can occupy more space within the stator slot 110 while the motor volume remains essentially unchanged, thereby improving the motor's copper fill rate and enabling the motor to have better performance (for example, higher motor efficiency, lower temperature rise, etc.). While satisfying the requirement that the motor performance remains essentially unchanged, the motors of each embodiment can have a more compact size and lighter weight, facilitating the spatial arrangement of the motor in the electric vehicle while reducing the weight and cost of the entire vehicle.

[0075] With reference to Tables 1 to 4, in some embodiments, within each stator slot group, the three branches of the same-phase winding are wound around the same number of slot layers. For example, if each stator slot is divided into six slot layers, and each stator slot group has 18 slot layers, then each branch is wound around six of the slot layers to ensure rotational symmetry among the three branches.

[0076] As shown in Tables 2 to 4, in the 18 slot layers of the 1st to 3rd stator slots, the first U-phase branch is wound around the odd-numbered slot layers of the 2nd stator slot and around the even-numbered slot layers of the 3rd stator slot; the second U-phase branch is wound around the odd-numbered slot layers of the 1st stator slot and around the even-numbered slot layers of the 2nd stator slot; the third U-phase branch is wound around the even-numbered slot layers of the 1st stator slot and around the odd-numbered slot layers of the 3rd stator slot.

[0077] Please refer to the Figures 6 to 8Taking the first U-phase branch of the U-phase winding as an example, the first pin of U-shaped flat wire 210a is inserted into the second slot layer of the 11th stator slot, and the second pin is inserted into the first slot layer of the 21st stator slot. The first pin of another U-shaped flat wire 210b connected to U-shaped flat wire 210a is inserted into the second slot layer of the 30th stator slot, and the second pin is inserted into the first slot layer of the 37th stator slot. The first pin of another U-shaped flat wire 210c connected to the other U-shaped flat wire 210b is inserted into the second slot layer of the 46th stator slot, and the second pin is inserted into the third slot layer of the 2nd stator slot. It should be understood that to achieve electrical connection between the U-shaped flat wires, the second pin of U-shaped flat wire 210a is bent toward the first pin 212 of U-shaped flat wire 210b to form a welded end. The second pin of U-shaped flat wire 210b is bent toward the first pin of U-shaped flat wire 210c to form a welded end.

[0078] In some embodiments, the first slot layer is the slot layer closest to the outer wall 104 of the stator core 100 , and the sixth slot layer is the slot layer closest to the inner wall 102 of the stator core 100 .

[0079] In some other embodiments, the first slot layer is the slot layer closest to the inner wall 102 of the stator core 100 , and the sixth slot layer is the slot layer closest to the outer wall 104 of the stator core 100 .

[0080] It should be understood that the above example is only an example of a portion of the first U-phase branch. Figure 8 It can be seen that the second pin of the U-shaped flat wire 210 c is further bent and welded to the first pin of another U-shaped flat wire, so that the first U-phase branch continues to extend to the 3rd, 4th, 5th and 6th slot layers.

[0081] Please refer to Table 2, Figure 7 and Figure 8 In some embodiments, the first U-phase branch is used as an example to illustrate each branch, and xy is defined as the yth layer of the xth stator slot; wherein x∈[1, 54], y∈[1, 6]. For example, 11.2 refers to the second slot layer of the 11th stator slot 110, and 21.1 refers to the first slot layer of the 21st stator slot 110. As shown in Table 2 and Figure 8 In the example shown, the current flow direction from U1+ to U1- in the first U-phase branch is: 02.1-11.2-21.1-30.2-37.1-46.2-02.3-11.4-21.3-30.4-37.3-46.4-02.5-11.6-21.5-30.6-37.5-46.6-03.6-48.5-38.6-29.5-19.6-10.5-03.4-48.3-38.4-29.3-19.4-10.3-03.2-48.1-38.2-29.1-19.2-10.1.

[0082] In some embodiments, the number of stator slots spanned by the hairpin end 220 or the welding end 230 is taken as the span. From the above exemplary examples, it can be seen that in the first U-phase branch, the span of the hairpin end 220 is a combination of 10 (e.g., 21-11), 7 (e.g., 37-30), and 10 (e.g., 54-46+2), while the span of the welding end 230 is always 9 (e.g., 30-21, 46-37). It should be understood that since the welding end 230 of the branch needs to be formed by welding the pins, in accordance with Table 2, Table 3, Figure 9 and Figure 10 The spans of the hairpin ends 220 of the second and third U-phase branches are also a combination of 7, 10, and 10, while the spans of the welding ends 230 are both 9. Based on this, U-shaped flat wires 210 are arranged in slots 1 to 6 in the second and third U-phase branches, respectively, to ensure that the three branches achieve potential balance under power supply conditions, thereby minimizing the adverse effects of circulating current on the motor, such as increased copper loss in the windings.

[0083] Based on the span relationship of the U-phase winding, the stator assembly 10 and the motor of each embodiment of the present application set the span of the welding end 230 to be the same (i.e., all 9), thereby making the bending angle of the first pin 212 of each U-shaped flat wire 210 the same, and the bending angle of the second pin 214 of each U-shaped flat wire 210 is also the same. This makes it easier for the process equipment to bend and weld the pins of the U-shaped flat wire 210, thereby reducing the difficulty of producing the winding 200 and improving production efficiency.

[0084] Please refer to the Figures 11 to 12 In some embodiments, the three branches of each phase winding are respectively introduced from the first slot layer of a corresponding stator slot and led out from the first slot layer of another corresponding stator slot.

[0085] Based on this, the incoming wires (U1+, U2+, U3+, V1+, V2+, V3+, W1+, W2+, and W3+) of the three-phase windings are all introduced from the first slot layer, which facilitates the layout and connection of the incoming wires. For example, U1+ is introduced from the first slot layer of the second stator slot 110, U2+ is introduced from the first slot layer of the 20th stator slot 110, and U3+ is introduced from the first slot layer of the 38th stator slot 110.

[0086] Correspondingly, the three-phase winding lead wires (U1-, U2-, U3-, V1-, V2-, V3-, W1-, W2-, and W3-) all extend from the first slot layer to facilitate their layout and connection. For example, U1- extends from the first slot layer of the 10th stator slot, U2- extends from the first slot layer of the 28th stator slot, and U3- extends from the first slot layer of the 46th stator slot.

[0087] In some other embodiments, the three branches of each phase winding enter from the sixth slot layer of the corresponding stator slot and exit from the sixth slot layer of another corresponding stator slot. Similar to the above embodiment, the three-phase winding 200 of this embodiment can also facilitate the arrangement and connection of the incoming and outgoing wires.

[0088] In some embodiments, the ends of the incoming wire and the outgoing wire of each branch are both hairpin ends wound between the first slot layer and the second slot layer.

[0089] Table 5 is another conductor arrangement data table for the first U-phase branch; Table 6 is another conductor arrangement data table for the second U-phase branch; Table 7 is another conductor arrangement data table for the third U-phase branch.

[0090] Table 5

[0091]

[0092] Table 6

[0093]

[0094]

[0095] Table 7

[0096]

[0097]

[0098] Referring to Tables 5 to 7, in some other embodiments, the spans of the hairpin ends of the three branches of the in-phase winding can also be a combination of 8, 8, and 11, while the spans of the welding ends of the three branches remain at 9. It should be understood that based on the above embodiments and the span combination of 8, 8, and 11, the potentials of the three branches of the in-phase winding can also be balanced, and the generation of circulating currents between the branches can be minimized to ensure normal operation of the motor.

[0099] In some embodiments, based on the aforementioned hairpin span combinations (7, 10, 10; 8, 8, 11), the stator assembly and motor of each embodiment of the present application require fewer types of U-shaped flat wires. The incoming wires for each winding branch are introduced through a portion of the hairpins in the first slot layer or the sixth slot layer, while the outgoing wires for each winding branch are correspondingly led out through another portion of the hairpins in the first slot layer or the sixth slot layer. This reduces the difficulty of manufacturing the stator assembly and improves the production efficiency of the stator assembly and the motor.

[0100] The above is a specific implementation method of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. A stator assembly, characterized in that: include: stator core and windings; The stator core includes an outer wall and an inner wall disposed in back-to-back relation. The inner wall is provided with a plurality of stator slots, and the plurality of stator slots are arranged spaced apart from each other along the circumference of the stator core. Along the radial direction of the stator core, each of the stator slots is divided into a plurality of slot layers. Three adjacent stator slots constitute a stator slot group. The winding includes a three-phase winding, and the three-phase winding is alternately wound around different stator slot groups in sequence along the circumference of the stator core; The winding of each phase includes three branches connected in parallel, and the three branches are rotationally symmetrical around the axial direction of the stator core; In each of the stator slot groups, each branch is wound around the odd-numbered slot layers of one stator slot and around the even-numbered slot layers of another stator slot.

2. The stator assembly according to claim 1, wherein Each branch includes a plurality of U-shaped flat wires connected in series, each U-shaped flat wire has a hairpin end, and a welding end is formed between two adjacent U-shaped flat wires; the hairpin end and the welding end are respectively located on different sides of the stator core; The lead-in wire of each branch is introduced from the first slot layer of the corresponding stator slot, and the lead-out wire of each branch is led out from the first slot layer of another corresponding stator slot; wherein, the first slot layer is the slot layer closest to the outer wall of the stator core; or, the first slot layer is the slot layer closest to the inner wall of the stator core.

3. The stator assembly according to claim 2, wherein: In each branch, the end of the incoming wire and the end of the outgoing wire are both hairpin ends; or, in each branch, the end of the incoming wire and the end of the outgoing wire are both welding ends.

4. The stator assembly according to claim 2 or 3, characterized in that: The U-shaped flat wire includes two pins, and the hairpin end is located between the two pins; The two pins are used to be respectively inserted into the odd-numbered slot layers and the even-numbered slot layers of different stator slot groups; wherein, the ends of the pins inserted into the odd-numbered slot layers are all bent at the same angle toward the first circumferential direction; the ends of the pins inserted into the even-numbered slot layers are all bent at the same angle toward the second circumferential direction; the first circumferential direction and the second circumferential direction are opposite.

5. The stator assembly according to claim 4, wherein: In each of the stator slot groups, the three branches of the corresponding in-phase windings are wound around the same number of slot layers.

6. The stator assembly according to any one of claims 1 to 3, characterized in that: The span of the hairpin end of each branch is a combination of 7, 10, and 10, and the span of the welding end of each branch is 9; wherein the span is the number of the stator slots spanned by the hairpin end or the welding end.

7. The stator assembly according to any one of claims 1 to 3, characterized in that: The span of the hairpin end of each branch is a combination of 8, 8, and 11, and the span of the welding end of each branch is 9; wherein the span is the number of the stator slots spanned by the hairpin end or the welding end.

8. The stator assembly according to any one of claims 1 to 3, characterized in that: In the three-phase winding, branches of windings of different phases are rotationally symmetric around the axial direction of the stator core.

9. The stator assembly according to any one of claims 1 to 3, characterized in that: The rotational symmetry angle of rotation is 120° or 240°.

10. A motor, characterized in that: The invention comprises a rotor assembly and a stator assembly according to any one of claims 1 to 9, wherein the rotor assembly is located inside the stator assembly.

11. An electric vehicle, characterized in that: Comprising the motor as claimed in claim 10.

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