Motor stator and preparation method thereof, motor, electric drive system and automobile

Abstract

The invention provides a motor stator and a preparation method thereof, a motor, an electric driving system and an automobile, and belongs to the technical field of electric driving force system manufacturing. The material of the motor stator comprises an amorphous soft magnetic alloy, the molecular formula of the amorphous soft magnetic alloy is FeaSibBcCudCoeMf, M is selected from at least one of Zr, Hf and Nb, 70 < = a < = 85, 0.65 < = b < = 8.5, 0.5 < = c < = 6, 0.7 < = d < = 2.5, 0.25 < = e < = 5, 2.5 < = f < = 8, and a + b + c + d + e + f = 100, the motor assembled by the motor stator can have higher power and efficiency, so that the electric vehicle has longer endurance, and the service life of the motor is prolonged. Therefore, the requirement of a user for a high-performance electric drive system is met.

Description

Technical Field

[0001] The present application relates to the technical field of electric drive system manufacturing, and more specifically, to a motor stator and a method for manufacturing the same, a motor, an electric drive system, and a vehicle. Background Art

[0002] For pure electric vehicles, the vehicle drive mainly relies on the electric drive system, and with the development of society, users have higher and higher performance requirements for the electric drive system. Specifically, users have begun to pursue electric drive systems with higher power and efficiency to make electric vehicles have longer endurance. However, the material systems currently used to manufacture motors (such as silicon steel materials) have basically reached their limits in terms of power and efficiency, and it is difficult to achieve further improvement. Therefore, there is an urgent need to introduce new material systems into the field of automotive drive technology to prepare motors with higher power and efficiency, so as to meet users' needs for high-performance motor systems. Summary of the invention

[0003] The purpose of the present application is to provide a motor stator and a preparation method thereof, a motor, an electric drive system and a car. The motor assembled from the motor stator can have both higher power and efficiency, so that the electric car has a longer battery life, thereby meeting the user's demand for a high-performance electric drive system.

[0004] The embodiment of the present application is implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides a motor stator, wherein the material of the motor stator includes an amorphous soft magnetic alloy, and the molecular formula of the amorphous soft magnetic alloy is: Fe a Si b B c Cu d Co e M f , wherein M is selected from at least one of Zr, Hf and Nb, 70≤a≤85, 0.65≤b≤8.5, 0.5≤c≤6, 0.7≤d≤2.5, 0.25≤e≤5, 2.5≤f≤8, and satisfies a+b+c+d+e+f=100.

[0006] In the above technical solution, the amorphous soft magnetic alloy with a specific molecular formula has the characteristics of high saturation magnetic induction intensity, low magnetic loss and good plasticity. This material is introduced into the field of electric drive systems and used as the main material for manufacturing motor stators, so that the corresponding motor has higher power and efficiency, thereby making the electric vehicle have a longer endurance, to meet users' needs for high-performance electric drive systems.

[0007] In a second aspect, an embodiment of the present application provides a method for preparing a motor stator as provided in the embodiment of the first aspect, comprising the following steps:

[0008] A strip material made of amorphous soft magnetic alloy and having a thickness of 0.02 to 0.03 mm is provided; the strip material is annealed, wherein the treatment temperature is not higher than 370°C, to obtain a punching sheet precursor; a plurality of punching sheet precursors are subjected to a first lamination composite treatment so that the plurality of punching sheet precursors are connected as a whole to obtain a punching sheet; the punching sheet is blanked to obtain a motor stator precursor; a plurality of motor stator precursors are subjected to a second lamination composite treatment so that the plurality of motor stator precursors are connected as a whole to obtain a motor stator.

[0009] In the above technical scheme, according to the above method, a thin sheet of amorphous soft magnetic alloy material with advantages such as high saturation magnetic induction intensity, low magnetic loss and good plasticity can be prepared into a motor stator, so that the corresponding motor has higher power and efficiency; wherein, when the strip is of a specific material and the thickness is in a specific range, the annealing temperature is set within a range not higher than 370°C, which can make the strip have relatively excellent toughness and strength after annealing, so that the strip has better processing performance (that is, improving the problem of slag falling or even breakage of the strip during subsequent processing), and thus the motor stator prepared by the strip of the specific material and specific thickness has higher power and efficiency.

[0010] In some optional embodiments, in the annealing step, the treatment temperature is 180-320° C., and the treatment time is 60-200 s.

[0011] In the above technical scheme, the processing temperature and time in the annealing process are limited to specific ranges, so that the annealed strip has more suitable toughness and strength, thereby having better processing performance (not prone to slagging and breakage during processing), and thus preparing a motor stator with better quality; at the same time, it can also make the strip have the advantage of smaller iron loss after annealing, so that the prepared motor stator has better power and efficiency.

[0012] In some optional embodiments, in the punching process step, the material of the punching die includes tungsten steel, and / or the punching pressure is 250-300 MPa.

[0013] In the above technical scheme, the yield strength of the strip of amorphous soft magnetic alloy in the embodiment of the present application is higher than the yield strength of conventional silicon steel. A blanking die of specific material is used and the blanking pressure is limited to a specific range, which is convenient for punching sheet forming and can reduce the risk of burrs generated on the strip during the blanking process (fewer burrs, and the iron loss of the corresponding material is usually smaller), so that the prepared motor stator has better power and efficiency, and at the same time, the blanking die can have a longer service life.

[0014] In some optional embodiments, the surface of the punching die further has a wear-resistant coating, the material of the wear-resistant coating includes TiCN, and / or the thickness of the wear-resistant coating is 1 to 7 μm.

[0015] In the above technical solution, a TiCN wear-resistant coating within a specific thickness range is provided on the surface of the punching die, wherein TiCN has both the high hardness of TiC and the high toughness of TiN, so that the punching die has relatively excellent wear resistance, thereby making the punching die have a longer service life.

[0016] In some optional embodiments, in the first lamination and composite processing step, glue bonding is used to connect two adjacent punching sheet precursors, and / or the thickness of the punching sheet is 0.2-0.3 mm.

[0017] In the above technical solution, the glue bonding method is convenient for batch implementation, which is helpful for the industrialization of the technical solution; at the same time, the thickness of the punching sheet is limited to a specific range (the existing silicon steel punching sheet is usually also within this thickness range), which helps to adapt to the existing preparation process.

[0018] In some optional embodiments, the material of the glue is selected from at least one of epoxy resin and acrylic resin, and / or the glue is a heat-curing glue and the curing time is no longer than 120 seconds.

[0019] In the above technical solution, epoxy resin and acrylic resin glues have the advantages of wide sources and easy preparation. At the same time, the use of heat-curing glues and glues with short curing times helps to improve preparation efficiency, thereby facilitating industrialization.

[0020] In some optional embodiments, the melting point of the glue is not less than 150° C., and / or the bonding strength of the glue is not less than 2 MPa.

[0021] In the above technical solution, glue with a high melting point and bonding strength is used (the motor will generate heat during high-speed operation, and glue with a high melting point and high bonding strength is not easy to fail), so that the motor has higher structural stability during high-speed operation.

[0022] In a third aspect, an embodiment of the present application provides a motor, comprising a motor stator and a motor rotor as provided in the embodiment of the first aspect.

[0023] In the above technical solution, the motor includes a motor stator as provided in the first aspect embodiment. Since the motor stator is made of a material with high saturation magnetic induction intensity, low magnetic loss and good plasticity, the motor has higher power and efficiency, thereby making the electric vehicle have a longer battery life to meet users' needs for high-performance electric drive systems.

[0024] In some optional embodiments, the outer peripheral wall of the motor rotor is provided with a carbon fiber wrapping layer.

[0025] In the above technical solution, a carbon fiber wrapping layer is provided on the outer peripheral wall of the motor rotor, which can effectively reduce the noise generated by the motor stator during operation. At the same time, it also helps to increase the power of the motor. In addition, the presence of the carbon fiber wrapping layer can also improve the structural strength of the motor, thereby increasing the speed of the motor.

[0026] In some optional embodiments, the thickness of the carbon fiber wrapping layer is 0.7-1.8 mm.

[0027] In the above technical solution, limiting the thickness of the carbon fiber wrapping layer within a specific range can achieve a better noise reduction effect and at the same time, can better improve the power and speed of the motor.

[0028] In a fourth aspect, an embodiment of the present application provides an electric drive system, comprising a motor as provided in the embodiment of the third aspect.

[0029] In a fifth aspect, an embodiment of the present application provides a car, comprising an electric drive system as provided in the embodiment of the fourth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A process flow chart of a method for preparing a motor stator provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0033] It should be noted that “and / or” in this application, such as “Feature 1 and / or Feature 2”, refers to the three situations of “Feature 1” alone, “Feature 2” alone, or “Feature 1” plus “Feature 2”.

[0034] In addition, in the description of the present application, unless otherwise specified, the meaning of "multiple" in "one or more" refers to two or more; the range of "value a ~ value b" includes the two end values ​​"a" and "b", and the "unit" in "value a ~ value b + unit of measurement" represents the "unit of measurement" of both "value a" and "value b".

[0035] The following is a detailed description of a motor stator and a preparation method thereof, a motor, an electric drive system, and a vehicle in an embodiment of the present application.

[0036] In a first aspect, an embodiment of the present application provides a motor stator, wherein the material of the motor stator includes an amorphous soft magnetic alloy, and the molecular formula of the amorphous soft magnetic alloy is: Fe a Si b B c Cu d Co e M f , wherein M is selected from at least one of Zr, Hf and Nb, 70≤a≤85, 0.65≤b≤8.5, 0.5≤c≤6, 0.7≤d≤2.5, 0.25≤e≤5, 2.5≤f≤8, and satisfies a+b+c+d+e+f=100.

[0037] In the present application, an amorphous soft magnetic alloy with a specific molecular formula has the characteristics of high saturation magnetic induction intensity, low magnetic loss and good plasticity. This material is introduced into the field of electric drive systems and used as the main material for manufacturing motor stators, so that the corresponding motor has higher power and efficiency, thereby making the electric vehicle have a longer battery life, thereby meeting users' needs for high-performance electric drive systems.

[0038] In a second aspect, an embodiment of the present application provides a method for preparing a motor stator as provided in the embodiment of the first aspect, comprising the following steps:

[0039] A strip material made of amorphous soft magnetic alloy and having a thickness of 0.02 to 0.03 mm (for example, but not limited to, a thickness of 0.02 mm, 0.021 mm, 0.022 mm, 0.023 mm, 0.024 mm, 0.025 mm, 0.026 mm, 0.027 mm, 0.028 mm, 0.029 mm and 0.03 mm) is provided; the strip material is annealed, wherein the treatment temperature is not higher than 370°C, to obtain a punching sheet precursor; a plurality of punching sheet precursors are subjected to a first lamination composite treatment so that the plurality of punching sheet precursors are connected as a whole to obtain a punching sheet; the punching sheets are blanked to obtain a motor stator precursor; a plurality of motor stator precursors are subjected to a second lamination composite treatment so that the plurality of motor stator precursors are connected as a whole to obtain a motor stator.

[0040] In the present application, according to a specific process, a thin sheet of amorphous soft magnetic alloy material with advantages such as high saturation magnetic induction intensity, low magnetic loss and good plasticity can be prepared into a motor stator, so that the corresponding motor has higher power and speed; wherein, when the strip is of a specific material and the thickness is within a specific range, the annealing temperature is set within a range not higher than 370°C, which can make the strip have relatively excellent toughness and strength after annealing, so that the strip has better processing performance (that is, improving the problem of slag falling or even breakage of the strip during subsequent processing), and thus the motor stator prepared by the strip of the specific material and specific thickness has higher power and efficiency.

[0041] It should also be noted that amorphous soft magnetic alloy materials are currently mostly used in transformer-related fields, and the treatment temperature of the material during the annealing process is usually higher than the crystallization temperature of the material. In this application, the inventors found that if the treatment temperature is set according to the conventional annealing process, the material after annealing is relatively brittle and difficult to carry out subsequent processing, that is, it is difficult to prepare the motor stator through the subsequent process, so the annealing treatment is innovatively adopted at a temperature lower than the crystallization temperature of the material.

[0042] In addition, the inventors have also found that the temperature of the annealing treatment is closely related to the iron loss of the material after annealing, and the iron loss is related to the power and efficiency of the corresponding motor. Based on this, the relevant parameters of the annealing treatment can be further optimized.

[0043] As an example, in the annealing step, the processing temperature is 180-320°C, for example but not limited to the processing temperature is any one of 180°C, 200°C, 220°C, 240°C, 260°C, 280°C, 300°C and 320°C or a range between any two of them; the processing time is 60-200s, for example but not limited to the processing time is any one of 60s, 80s, 100s, 120s, 140s, 160s, 180s and 200s or a range between any two of them.

[0044] In this embodiment, the processing temperature and time during the annealing process are limited to specific ranges, so that the strip after annealing has more suitable toughness and strength, thereby having better processing performance (not prone to slagging and breakage during processing), thereby preparing a motor stator with better quality; at the same time, the strip can also have the advantage of less iron loss after annealing, thereby making the prepared motor stator have better power and efficiency.

[0045] As an example, in the punching process, the material of the punching die includes tungsten steel, and / or the punching pressure is 250-300 MPa, for example but not limited to any one of 250 MPa, 260 MPa, 270 MPa, 280 MPa, 290 MPa and 300 MPa or a range between any two of them.

[0046] In this embodiment, the yield strength of the strip of amorphous soft magnetic alloy in the embodiment of the present application is higher than the yield strength of conventional silicon steel. A punching die of a specific material is used and the punching pressure is limited to a specific range, which is convenient for punching sheet forming and can reduce the risk of burrs generated on the strip during the punching process (fewer burrs and smaller iron loss of the corresponding material), so that the prepared motor stator has better power and efficiency, and at the same time, the punching die can have a longer service life.

[0047] As an example, the surface of the blanking die also has a wear-resistant coating, the material of the wear-resistant coating includes TiCN, and / or the thickness of the wear-resistant coating is 1 to 7 μm, for example but not limited to the thickness of the coating is any point value of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm and 7 μm or a range value between any two of them.

[0048] In this embodiment, a TiCN wear-resistant coating within a specific thickness range is provided on the surface of the punching die, wherein TiCN has both the high hardness of TiC and the high toughness of TiN, so that the punching die has relatively excellent wear resistance, thereby making the punching die have a longer service life.

[0049] As an example, in the first lamination and compounding step, glue bonding is used to connect two adjacent punching sheet precursors, and / or the thickness of the punching sheet is 0.2-0.3 mm.

[0050] In this embodiment, the glue bonding method is convenient for batch implementation, which helps the industrialization of the technical solution; at the same time, the thickness of the punching sheet is limited to a specific range (the existing silicon steel punching sheet is usually also within this thickness range), which helps to adapt to the existing preparation process.

[0051] It should be noted that the method of bonding the punching sheet precursor by glue is not limited and can be carried out according to conventional processes in the art, for example, vacuum dipping or surface brushing can be used to achieve it.

[0052] As an example, the material of the glue is selected from at least one of epoxy resin and acrylic resin, and / or the glue is a heat-curing glue and the curing time is not more than 120s, for example, it can be any point value of 50s, 60s, 70s, 80s, 90s, 100s, 110s and 120s or a range value between any two of them.

[0053] In this embodiment, epoxy resin and acrylic resin glues have the advantages of being widely available and easy to prepare. At the same time, the use of heat-curing glues and glues with a short curing time helps to improve the preparation efficiency, thereby facilitating industrialization.

[0054] As an example, the melting point of the glue is not lower than 150°C, for example, the melting point can be any one of 150°C, 170°C, 200°C, 220°C and 240°C, or a range between any two of them; and / or, the bonding strength of the glue is not lower than 2MPa, for example, it can be any one of 2MPa, 3MPa, 4MPa, 5MPa and 6MPa, or a range between any two of them.

[0055] In this embodiment, glue with a high melting point and bonding strength is used (the motor will generate heat during high-speed operation, and glue with a high melting point and high bonding strength is not easy to fail), so that the motor has higher structural stability during high-speed operation.

[0056] It should be noted that the second lamination process is not limited in its method and can be performed in a conventional manner in the art, such as by point connection, welding or gluing.

[0057] It should be noted that any process or step not specifically described or limited in the motor stator preparation process may be arranged according to conventional selections in the art.

[0058] As an example, the process flow chart of the method for preparing the motor stator is shown in FIG. Figure 1 .

[0059] In a third aspect, an embodiment of the present application provides a motor, comprising a motor stator and a motor rotor as provided in the embodiment of the first aspect.

[0060] In the present application, the motor includes a motor stator as provided in the first aspect embodiment. Since the motor stator is made of a material with high saturation magnetic induction intensity, low magnetic loss and good plasticity, the motor has higher power and efficiency, thereby making the electric vehicle have a longer battery life to meet users' needs for high-performance electric drive systems.

[0061] As an example, the material of the motor rotor is conventional silicon steel.

[0062] It should be noted that the inventors have found that when the material of the motor stator adopts the specific material provided in the embodiment of the present application, the assembled motor has a large noise problem during operation. Based on this, the structure of the motor can be optimized.

[0063] As an example, the outer peripheral wall of the motor rotor is provided with a carbon fiber wrapping layer.

[0064] In this embodiment, a carbon fiber wrapping layer is provided on the outer peripheral wall of the motor rotor, which can effectively reduce the noise generated by the motor stator during operation. At the same time, it also helps to increase the power of the motor. In addition, the presence of the carbon fiber wrapping layer can also improve the structural strength of the motor, thereby increasing the speed of the motor.

[0065] As an example, the thickness of the carbon fiber wrapping layer is 0.7 to 1.8 mm, for example but not limited to the thickness of any point value among 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm and 1.8 mm or a range value between any two of them.

[0066] In this embodiment, limiting the thickness of the carbon fiber wrapping layer within a specific range can achieve a better noise reduction effect and at the same time, can better improve the power and speed of the motor.

[0067] It should be noted that the material of the carbon fiber wrapping layer is not limited, for example, it can be T800 or T600 carbon fiber material.

[0068] It should be noted that any structural or functional unit in the motor that is not specifically described or limited may be configured according to conventional options in the art.

[0069] In a fourth aspect, an embodiment of the present application provides an electric drive system, comprising a motor as provided in the embodiment of the third aspect.

[0070] In a fifth aspect, an embodiment of the present application provides a car, comprising an electric drive system as provided in the embodiment of the fourth aspect.

[0071] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0072] Example 1

[0073] The present invention provides a method for manufacturing a motor, comprising the following steps:

[0074] Preparation of motor stator:

[0075] Provide a strip made of amorphous soft magnetic alloy and having a single sheet thickness of 0.02 mm, wherein the molecular formula of the amorphous soft magnetic alloy is Fe 80Si6B4Cu 1.5 Co 3.5 Zr5, the strip is heat-annealed at 240°C for 120s to obtain a punching sheet precursor; 10 sheets of the punching sheet precursor are stacked by vacuum dipping, wherein the glue is made of epoxy resin, has a curing time of 100s, a melting point of 200°C, and a bonding strength of 5MPa, to obtain a punching sheet with a thickness of 0.2mm; a punching die made of tungsten steel (with a 5μm thick TiCN wear-resistant coating on the surface) is used to punch the sheet (the punching pressure is 280MPa) to obtain a motor stator precursor; 20 sheets of the motor stator precursor are stacked by buckle point connection to obtain a motor stator.

[0076] Motor assembly:

[0077] The motor rotor is made of silicon steel, and the outer peripheral wall includes a carbon fiber wrapping layer made of T800 material and 1.2 mm thick. The motor stator and the motor rotor are assembled into a motor.

[0078] Example 2

[0079] The embodiment of the present application provides a method for preparing a motor, which differs from Embodiment 1 only in that: the strip is subjected to heat preservation annealing at 320° C. for 120 seconds to obtain a punching sheet precursor.

[0080] Example 3

[0081] The embodiment of the present application provides a method for preparing a motor, which differs from Embodiment 1 only in that: the strip is subjected to heat preservation annealing at 360° C. for 120 seconds to obtain a punching sheet precursor.

[0082] Example 4

[0083] The present embodiment provides a method for preparing a motor, which differs from the first embodiment only in that:

[0084] The outer peripheral wall of the motor rotor is not covered with carbon fiber.

[0085] Comparative Example 1

[0086] The comparative example of the present application provides a method for preparing a motor, which differs from Example 1 only in that:

[0087] The motor stator is made of silicon steel.

[0088] Comparative Example 2

[0089] The comparative example of the present application provides a method for preparing a motor, which differs from Example 1 only in that:

[0090] The motor stator is made of silicon steel, and the outer wall of the motor rotor is not wrapped with a carbon fiber layer.

[0091] Test example

[0092] Motor performance test

[0093] Test method:

[0094] The motors prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were numbered respectively, and then the core iron loss, motor efficiency, upper speed limit and noise of each motor were tested, and the test results were statistically summarized in Table 1.

[0095] Specifically, the test steps for the motor core iron loss are as follows:

[0096] The test is carried out in accordance with the requirements of the national standard GB / T 20835-2024 Generator stator core magnetization test guide.

[0097] Specifically, the test steps for motor efficiency are as follows:

[0098] The test is carried out in accordance with the requirements of 6.3.8 of the national standard GB-T 18488-2024 drive motor system for electric vehicles.

[0099] Specifically, the test steps for the upper limit of the motor speed are as follows:

[0100] The test is carried out in accordance with the requirements of 6.3.7 of the national standard GB-T 18488-2024 drive motor system for electric vehicles.

[0101] Specifically, the test steps for motor noise are as follows:

[0102] The test is carried out in accordance with the requirements of the national standard GB-T 10069.3-2024 Rotating motor noise measurement method and limit values.

[0103] Table 1

[0104]

[0105] Referring to Table 1, it can be seen from the test results of Examples 1 to 3 and Comparative Example 1 that in the embodiments of the present application, an amorphous soft magnetic alloy strip of a specific material and thickness is used as a substrate, and the motor stator is prepared according to a specific annealing process. Compared with the motor stator prepared by conventional silicon steel, the former corresponds to a motor with higher power and efficiency.

[0106] It can be seen from the test results of Examples 1 to 3 that when the material and thickness of the substrate are constant, the annealing temperature is controlled within a specific range. Compared with exceeding the temperature range, the former corresponds to a smaller iron loss of the motor core and the motor has higher power and efficiency.

[0107] From the test results of Examples 1 to 3 and Example 4, Comparative Examples 1 and 2, it can be seen that coating the motor stator with a carbon fiber wrapping layer can help reduce the noise of the motor during operation, and at the same time, it can also help to increase the power of the motor and the upper limit of the motor speed.

[0108] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

Claims

1. A motor stator, characterized in that: The material of the motor stator includes an amorphous soft magnetic alloy, and the molecular formula of the amorphous soft magnetic alloy is: Fe a Si b B c Cu d Co e M f , wherein M is selected from at least one of Zr, Hf and Nb, 70≤a≤85, 0.65≤b≤8.5, 0.5≤c≤6, 0.7≤d≤2.5, 0.25≤e≤5, 2.5≤f≤8, and satisfies a+b+c+d+e+f=100.

2. A method for preparing a motor stator according to claim 1, characterized in that: The following steps are involved: Providing a strip made of the amorphous soft magnetic alloy and having a thickness of 0.02 to 0.03 mm; Annealing the strip, wherein the treatment temperature is not higher than 370° C., to obtain a sheet precursor; Performing a first lamination and compounding process on the plurality of punching sheet precursors so that the plurality of punching sheet precursors are connected into a whole to obtain a punching sheet; Punching the punching sheet to obtain a motor stator precursor; The plurality of motor stator precursors are subjected to a second lamination composite process so that the plurality of motor stator precursors are connected into a whole to obtain the motor stator.

3. The method for preparing a motor stator according to claim 2, characterized in that: In the annealing step, the treatment temperature is 180-320° C. and the treatment time is 60-200 seconds.

4. The method for preparing a motor stator according to claim 2, characterized in that: In the punching process, the material of the punching die includes tungsten steel, and / or the punching pressure is 250-300 MPa.

5. The method for preparing a motor stator according to claim 4, characterized in that: The surface of the punching die also has a wear-resistant coating, the material of the wear-resistant coating includes TiCN, and / or the thickness of the wear-resistant coating is 1 to 7 μm.

6. The method for preparing a motor stator according to any one of claims 2 to 5, characterized in that: In the first lamination and compounding step, the connection between two adjacent punching sheet precursors is achieved by gluing, and / or the thickness of the punching sheet is 0.2-0.3 mm.

7. The method for preparing a motor stator according to claim 6, characterized in that: The material of the glue is selected from at least one of epoxy resin and acrylic resin, and / or the glue is a heat-curing glue and the curing time is no longer than 120 seconds.

8. The method for preparing a motor stator according to claim 7, characterized in that: The melting point of the glue is not less than 150° C., and / or the bonding strength of the glue is not less than 2 MPa.

9. A motor, characterized in that: It comprises the motor stator and the motor rotor as claimed in claim 1.

10. The motor according to claim 9, characterized in that The outer peripheral wall of the motor rotor is provided with a carbon fiber wrapping layer.

11. The motor according to claim 10, characterized in that The thickness of the carbon fiber wrapping layer is 0.7-1.8 mm.

12. An electric drive system, characterized in that: The invention comprises the motor according to any one of claims 9 to 11.

13. A car, characterized in that: Comprising the electric drive system as claimed in claim 12.

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