Range extender cooling structure, manufacturing method, range extender and vehicle

Abstract

The invention discloses a range extender cooling structure and a manufacturing method thereof, a range extender and a vehicle, and the range extender cooling structure comprises an inner shell arranged between a stator assembly and a range extender shell; the low-thermal-resistance heat-conducting layer is filled in the crown end and the welding end of the stator assembly and the gap between the winding and the iron core by adopting a heat-conducting insulating material, and an integrated structure is formed; a cooling water channel is arranged on the outer wall of the inner shell; the inner wall of the inner shell is provided with a first groove for a heat conduction insulating material to permeate into the gap. According to the invention, a low-thermal-resistance heat conduction layer is formed by using a high-thermal-conductivity insulating material to replace traditional insulating paint and air, and the heat exchange area is increased by designing a through channel, a fixed groove and an end surface cooling water channel, so that the heat dissipation effect is remarkably improved; the problems that the stator temperature rise is too high and the efficiency is reduced due to the fact that heat cannot be taken away in time when the range extender operates for a long time are solved.

Description

Technical Field

[0001] The present invention relates to the field of motor technology, and in particular to a range extender cooling structure and a manufacturing method, a range extender, and a vehicle. Background Art

[0002] In the field of new energy vehicles, range extenders are being used more and more widely, and their cost, efficiency, volume and quality have attracted much attention from car companies. Liquid-cooled (coolant or oil) range extenders are the current mainstream cooling method. Through optimized design and parametric design, the stack length and geometric structure of the motor can be effectively reduced, thereby achieving the goal of reducing costs and increasing efficiency.

[0003] When the range extender operates under rated conditions, the heat loss of the windings and the core accounts for more than 90%. At present, the cooling water channels of the mainstream water-cooled range extender are mainly arranged in the shell, and the inner and outer shells are sealed by friction welding or sealing rings. The axial height of the water channel is usually higher than the stack length of the core, and can even be up to twice or more. The heat from the main heat source is transferred to the shell through the core and then to the cooling water. According to the principle of heat conduction, under the condition of a certain temperature difference, the heat exchange is proportional to the effective heat exchange area and the heat transfer coefficient. That is, the larger the effective heat exchange area and the heat transfer coefficient, the greater the heat exchange.

[0004] The Chinese patent "A water-cooled motor structure", announcement number CN218678728U, announcement date 2023.03.21, discloses a motor structure including a motor front cover, a motor housing and a motor rear cover from top to bottom, wherein a stator assembly is arranged in the motor housing, the motor front cover is covered on the motor housing above the upper potting cover, and the motor rear cover is covered on the motor housing below the lower potting cover. A front cover radial water channel is arranged near the outside of the motor front cover, a housing radial water channel is arranged on the motor housing directly below the front cover radial water channel, and a rear cover radial water channel is arranged on the motor rear cover directly below the housing radial water channel. An annular water channel is arranged in the motor front cover between the front cover radial water channel and the front cover middle hole, and an annular water channel is arranged in the motor rear cover between the rear cover radial water channel and the rear cover middle hole. However, the structure adopts the form of front and rear potting covers, which can replace part of the air heat transfer and improve the heat transfer coefficient, but the contact area between the remaining windings is small and cannot fill the gap part in the flat wire winding. Since heat transfer between multiple solids is closely related to the thermal resistance of the interface in addition to its own thermal conductivity, the heat transfer coefficient and heat transfer area are increased by potting cover. The assembly between the potting cover, the shell, and the winding will seriously affect the heat transfer effect. In addition, the structure adopts the method of assembly first and then potting, which makes it difficult to judge whether the potting effect meets the requirements. Adding motor parts will increase the cost of the motor, increase the difficulty of manufacturing, and increase the cost of industrialization. At the same time, the structure does not take into account the coordination of the waterway and potting, and it is difficult to maximize the effective heat transfer area and heat transfer coefficient.

[0005] The Chinese patent "A composite potting cooling structure for motor stator windings", publication number CN108964318A, publication date 2018.12.07, discloses a cooling structure including a casing, a stator core, a winding wound on the stator core, a heat pipe and an insulating heat-conductive potting glue. The stator core is fixed to the inner wall of the casing, and there is a cooling water channel inside the casing. The cooling water channel covers the stator core and the winding end in the axial direction. A heat pipe is placed in the hollow cylindrical area between the winding end and the casing. The heat absorbing end of the heat pipe is in close contact with the outer ring of the winding end, and the cooling end is in close contact with the inner wall of the casing. The hollow cylindrical area from the motor winding end to the inner wall of the casing is potted with an insulating heat-conductive potting glue. However, the industrialization of this cooling structure is extremely difficult. The difficulty and time of installing the heat pipe on the winding are challenges. The heat pipe will greatly increase the cost of the motor. At the same time, the heat pipe and the winding are both conductive materials, which are prone to conduction, and their safety and stability are low. In addition, this structure only potting the end of the winding, the heat exchange area is small, and the potting glue has no contact with the middle end of the winding and the inner winding of the core. Not only does it fail to provide insulation effect between the winding and the core, but the heat exchange area is also small.

[0006] The cooling method of water-cooled motors is an indirect cooling method, which requires passing through multiple heat conductors from the heat source to the heat sink. When the range extender is running for a long time under normal operating conditions (rated operating conditions), the windings and iron core will generate a lot of heat that needs to be transferred to the cooling water. There are usually two heat transfer paths: Path 1: winding → insulating varnish → insulating paper → insulating varnish → iron core → shell → cooling water; Path 2: winding → air → shell → cooling water. Among them, the insulating varnish and insulating paper in path 1 and the air in path 2 are heat conduction barriers.

[0007] According to the heat conduction formula Q=λ×A×△T (where A is the heat exchange area, λ is the heat transfer coefficient, △T is the temperature difference, and Q is the heat transfer amount), there is a large contact area between the air and the shell in heat transfer path 2, but the thermal conductivity of air is only 0.026W / (m×K), and the existing potting scheme does not fully utilize the effective heat exchange area.

[0008] Based on the above heat transfer path 1, most existing motors use low thermal conductivity insulating paint to fill the gap between the winding and the core to play an insulating and heat conducting role. However, it is necessary to calculate the amount of paint dripping, use a specific paint dripping process, and paint dripping equipment to complete it. If the amount of paint dripping, the paint dripping process, and the paint dripping angle are wrong during this process, it will cause abnormal temperature rise of the motor and burn the motor.

[0009] New energy motors and range extenders are developing towards high power density, high speed and miniaturization, requiring a smaller volume to dissipate more heat, so the thermal management of motors is one of the bottlenecks hindering the further development of motors. A certain safety gap must be left between the winding and the housing to ensure the safe and stable operation of the motor, which contradicts the development direction of small motor size.

[0010] Therefore, a new cooling structure is needed to improve the heat exchange efficiency and solve the above problems. Summary of the invention

[0011] The purpose of the present invention is to provide a range extender cooling structure and manufacturing method, a range extender, and a vehicle. The liquid cooling heat dissipation structure can effectively solve the problems existing in the prior art, improve the heat dissipation efficiency of the range extender, increase the service life and stability, and reduce costs.

[0012] To achieve the above objectives, in a first aspect, the present invention provides a range extender cooling structure, comprising:

[0013] An inner housing is placed between the stator assembly and the range extender housing;

[0014] The low thermal resistance heat-conducting layer is filled with heat-conducting insulating materials at the crown end, welding end and the gap between the winding and the core of the stator assembly to form an integrated structure;

[0015] The outer wall of the inner shell is provided with a cooling water channel; the inner wall of the inner shell is provided with a first groove for allowing the heat-conducting insulating material to penetrate into the gap.

[0016] In some optional embodiments of the present invention, the inner wall of the inner shell is further provided with a fixing groove; the low thermal resistance heat conductive layer penetrates into the fixing groove to increase the heat exchange area between the low thermal resistance heat conductive layer and the inner shell.

[0017] Preferably, the fixing grooves include a plurality of welding end fixing grooves arranged at the welding end and a plurality of crown end fixing grooves arranged at the crown end.

[0018] Preferably, the cross-sectional shape of the fixing groove is a circle, an isosceles triangle, an equilateral triangle or an isosceles trapezoid.

[0019] Further preferably, the height of the welding end fixing groove is equal to the height of the welding end winding plus 3 to 10 mm.

[0020] Further preferably, the height of the crown end fixing groove is equal to the height of the crown end winding plus 3 to 10 mm.

[0021] In some optional embodiments of the present invention, the low thermal resistance heat conducting layer comprises:

[0022] A crown end heat conductive layer, covering the crown end of the stator assembly;

[0023] A welding end heat conductive layer covering the welding end of the stator assembly; and

[0024] The middle section heat-conducting layer is filled in the gap between the winding and the iron core in the stator slot.

[0025] In some optional embodiments of the present invention, there are multiple first grooves, which can be evenly arranged or arranged in areas where heat is concentrated.

[0026] Preferably, the first groove extends along the axial direction of the inner shell from the bottom of the crown end to the bottom of the welding end.

[0027] Preferably, the cross-sectional shape of the first groove is a circle, an isosceles triangle, an equilateral triangle or an isosceles trapezoid.

[0028] In some optional embodiments of the present invention, the axial height of the cooling water channel is greater than or equal to the sum of the axial height of the stator core, the potting height of the welding end, and the potting height of the crown end.

[0029] In some optional embodiments of the present invention, at least one end surface of the inner shell is provided with an end surface water channel, wherein the end surface water channel is used to increase the effective heat exchange area between the inner shell and the low thermal resistance heat conducting layer and cool the bearing.

[0030] Preferably, the end surface water channel is provided on the end surface of the inner shell at the welding end of the stator assembly.

[0031] In a second aspect, the present invention provides a method for manufacturing a range extender cooling structure, comprising:

[0032] An inner housing is designed, wherein the outer wall of the inner housing is provided with a cooling water channel, and the inner wall of the inner housing is provided with a first groove; the inner housing is installed between the stator assembly and the range extender housing;

[0033] The crown end, welding end and gap between the winding and the core of the stator assembly are filled with thermally conductive insulating material. Multiple negative pressure potting is combined with normal pressure potting to fully fill the gap with the thermally conductive insulating material through the first groove to form an integrated low thermal resistance thermal conductive layer.

[0034] In some optional embodiments of the present invention, when designing the inner shell, a fixing groove is further provided on the inner wall of the inner shell; a low thermal resistance heat conductive layer penetrates into the fixing groove to increase the heat exchange area between the low thermal resistance heat conductive layer and the inner shell.

[0035] In some optional embodiments of the present invention, when designing the inner casing, an end surface water channel is provided on the end surface of the inner casing located at the welding end of the stator assembly to increase the effective heat exchange area with the low thermal resistance heat conductive layer and cool the bearing.

[0036] In some optional embodiments of the present invention, the thermally conductive insulating material is epoxy glue or modified silicone glue.

[0037] In a third aspect, the present invention provides a range extender, comprising the cooling structure described in the first aspect.

[0038] In a fourth aspect, the present invention provides a vehicle comprising the range extender described in the third aspect.

[0039] The present invention has the following beneficial effects:

[0040] Based on the research on the heat transfer path of the "range extender", the heat transfer obstacles on the two heat transfer paths are insulating paint and air. The present invention uses high thermal conductivity and insulating materials to replace insulating paint and air, which greatly improves the cooling capacity of the range extender, thereby improving the stable operating power of the motor, and improving the motor's service life and stability.

[0041] When using "high thermal conductivity insulation material" to replace air heat conduction, the contact area between the "high thermal conductivity insulation material" and the inner shell is increased by designing the first groove, the fixed groove, and the end surface cooling water channel, thereby further improving the heat dissipation efficiency.

[0042] The design of the present invention performs "integrated" series encapsulation of the stator crown end, the welding end, the stator slot and the inner shell, thereby achieving the purpose of increasing the heat exchange area and reducing the interface thermal resistance.

[0043] The use of an "integrated" series-potted motor (range extender) eliminates the two processes of insulating paint dripping and insulating powder coating, saving materials and labor hours and reducing production costs.

[0044] The height of the paint end of the motor (range extender) of the present invention can be reduced to 1 mm to 5 mm from the two end covers, which can further improve the stable power, reduce the stator and rotor stacking length and copper usage, reduce the axial height of the motor, reduce the weight of the range extender, improve the power density and torque density, and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments disclosed in the present invention, the drawings of the embodiments will be briefly introduced below. These drawings are only used for illustrative purposes and are not intended to limit the protection scope of the present invention.

[0046] Figure 1 is a structural schematic diagram of the stator assembly;

[0047] Figure 2 is a cross-sectional schematic diagram of a range extender using the cooling structure of the present invention;

[0048] Figure 3 is a three-dimensional schematic diagram of a low thermal resistance heat conducting layer of the present invention;

[0049] Figure 4 is a schematic cross-sectional view of a low thermal resistance heat conducting layer of the present invention;

[0050] Figure 5 The three-dimensional structure of the inner shell of the present invention is shown in FIG. Figure 1 ;

[0051] Figure 6 The three-dimensional structure of the inner shell of the present invention is shown in FIG. Figure 2 ;

[0052] Figure 7 The three-dimensional structure of the inner shell of the present invention is shown in FIG. Figure 3 ;

[0053] Figure 8 It is a front view schematic diagram of the inner shell of the present invention. DETAILED DESCRIPTION

[0054] The technical solution of the present invention (including the preferred technical solution) is further described in detail below by means of the accompanying drawings and by listing some optional embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0055] Example 1

[0056] like Figure 1 and Figure 2 As shown, the range extender cooling structure of the present invention mainly includes an inner shell 4 and a low thermal resistance heat conductive layer 2. The low thermal resistance heat conductive layer 2 is filled with a heat conductive insulating material in the crown end 31, the welding end 33 of the stator assembly 3 and the gap between the winding and the iron core 32 to form an integrated structure. Among them, the inner shell 4 is placed between the stator assembly 3 and the range extender shell 5, and the outer wall of the inner shell 4 is provided with a cooling water channel 41, and the inner wall is provided with a first groove 43 for the heat conductive insulating material to penetrate into the gap. The rotor assembly 1 is connected to the inside of the stator assembly 3.

[0057] like Figure 2 As shown, the inner wall of the inner shell 4 is completely covered with the low thermal resistance heat conducting layer 2, thereby increasing the effective heat exchange area. Figure 1 , Figure 4 and Figure 8 As shown, the relationship among the axial height L1 of the cooling water channel 41, the axial height L2 of the stator core 32, the potting height H2 of the welding end 33, and the potting height H1 of the crown end 31 is L1≥L2+H1+H2, ensuring that the effective heat exchange area is as large as possible within the limited space.

[0058] like Figure 3 , 4As shown, the low thermal resistance heat conducting layer 2 includes a crown end heat conducting layer 21, a middle section heat conducting layer 22 and a welding end heat conducting layer 23. The crown end heat conducting layer 21 covers the crown end 31 of the stator assembly, the welding end heat conducting layer 23 covers the welding end 33 of the stator assembly, and the middle section heat conducting layer 22 fills the gap between the winding and the iron core in the stator slot. These three parts of the heat conducting layer are integrally formed by heat conductive insulating materials to form a complete low thermal resistance heat conducting layer 2.

[0059] like Figure 5 and Figure 6 As shown, a first groove 43 of a specific shape is designed on the inner wall of the inner shell 4. There are multiple first grooves 43, generally greater than or equal to 4, and multiple first grooves 4 can be evenly arranged or arranged in the area where heat is concentrated. These first grooves 43 extend from the bottom of the crown end to the bottom of the welding end along the axial direction of the inner shell 4, and use the capillary penetration principle to make the high thermal conductivity insulation material better and more comprehensively cover the motor heat source and the inner wall of the inner shell. By combining multiple negative pressure potting with normal pressure potting, the two interface thermal resistances (the interface thermal resistance between the thermal conductive material and the heat source, and the interface thermal resistance between the thermal conductive material and the shell) are reduced, while improving the integrity and stability of the overall structure, which is beneficial to better transfer the heat of the winding and the core to the heat sink, and improves the NVH performance of the assembly.

[0060] In some embodiments of the present invention, the cross-sectional shape of the first groove 43 is a circle, an isosceles triangle, an equilateral triangle or an isosceles trapezoid.

[0061] In some embodiments of the present invention, the cross-sectional shape of the first groove 43 is a circle with a diameter of 1 to 2 mm.

[0062] In some embodiments of the present invention, the cross-sectional shape of the first groove 43 is an isosceles triangle or an equilateral triangle with a side length of 1 to 2 mm.

[0063] Example 2

[0064] This embodiment provides an optimized design of a range extender cooling structure. Compared with Embodiment 1, this embodiment further designs a fixing groove on the inner wall of the inner shell 4 on the basis of Embodiment 1 to increase the heat exchange area between the low thermal resistance heat conducting layer and the inner shell.

[0065] like Figure 5 and Figure 6 As shown, the inner wall of the inner shell 4 is also provided with a fixing groove, and the low thermal resistance heat conductive layer 2 penetrates into the fixing groove to increase the heat exchange area between the low thermal resistance heat conductive layer 2 and the inner shell 4. The fixing groove includes a plurality of welding end fixing grooves 44 provided at the welding end and a plurality of crown end fixing grooves 45 provided at the crown end.

[0066] In some embodiments of the present invention, the cross-sectional shape of the fixing groove is a circle, an isosceles triangle, an equilateral triangle or an isosceles trapezoid.

[0067] In some embodiments of the present invention, the height H4 of the welding end fixing groove 44 is equal to the welding end winding height L3 plus 3 to 10 mm.

[0068] In some embodiments of the present invention, the height H3 of the crown end fixing groove 45 is equal to the crown end winding height L4 plus 3 to 10 mm.

[0069] In some embodiments of the present invention, the fixing groove does not overlap with the first groove 41. The number of the welding end fixing groove 44 and the crown end fixing groove 45 can be set as needed, and is generally not less than 4. The thermally conductive insulating material of the low thermal resistance thermal conductive layer penetrates into the fixing groove, specifically, Figure 3 As shown, the heat-conducting insulating material of the low thermal resistance heat-conducting layer penetrates into the first groove 41 to form the first groove penetration part 24, penetrates into the welding end fixing groove 44 to form the welding end fixing groove penetration part 25, and penetrates into the crown end fixing groove 45 to form the crown end fixing groove penetration part 26. In this way, the low thermal resistance heat-conducting layer and the inner shell form a larger contact area, thereby increasing the heat exchange area, improving the heat dissipation efficiency, and also strengthening the mechanical connection between the low thermal resistance heat-conducting layer and the inner shell, improving the stability and reliability of the overall structure.

[0070] Example 3

[0071] This embodiment further describes the specific structure of the cooling water channel based on any one of the embodiments 1 to 3. In this embodiment, the cooling water channel 41 is a plurality of annular water channels, each of which axially surrounds the outer wall of the inner shell, and the plurality of annular water channels are axially arranged in the inner shell.

[0072] The annular water channel surrounds the outer wall of the inner shell circumferentially, and the water inlet and the water outlet are separated. Multiple annular water channels are arranged in the axial direction of the inner shell 4, and each of them independently inlets and outlets water, forming a relatively independent waterway system. The water inlet and outlet of each annular water channel are located at the same end of the inner shell, which is convenient for pipe connection and installation.

[0073] This annular water channel design increases the contact area between the cooling water and the inner shell, improving the heat dissipation efficiency. At the same time, the axial height of the cooling water channel is greater than or equal to the sum of the axial height of the stator core, the potting height of the welding end, and the potting height of the crown end, ensuring sufficient cooling area.

[0074] In a specific embodiment of the present invention, Figure 7 As shown, the cooling water channel 41 is a combination of a spiral and annular shape, and a plurality of water inlets and water outlets can be provided, which are located on the end or the outer circumferential wall of the housing as required.

[0075] Example 4

[0076] Based on any one of the embodiments 1 to 3, this embodiment further designs an end surface water channel on at least one end surface of the inner shell. The design of the end surface water channel increases the effective heat exchange area between the low thermal resistance heat conductive layer and can effectively take away the heat of the bearing, thereby achieving the effect of cooling the motor bearing.

[0077] like Figure 6 and Figure 7 As shown, in some embodiments of the present invention, the end surface water channel 42 is arranged on the end surface of the inner housing at the welding end of the stator assembly. The water inlet of the end surface water channel is connected with the water inlet of the cooling water channel, and the water outlet of the end surface water channel is connected with the water outlet of the cooling water channel, forming a complete water circulation system.

[0078] Through the design of the end face water channel, not only the overall heat dissipation efficiency is improved, but also the cooling of the bearing area is especially strengthened, which extends the service life of the bearing and improves the reliability of the range extender.

[0079] Example 5

[0080] This embodiment provides a method for manufacturing a range extender cooling structure, comprising the following steps:

[0081] The inner shell is designed, the outer wall of which is provided with a cooling water channel, and the inner wall of which is provided with a first groove.

[0082] Install the inner housing between the stator assembly and the range extender housing.

[0083] The crown end, welding end and gap between the winding and the core of the stator assembly are filled with thermally conductive insulating material. Multiple negative pressure potting is combined with normal pressure potting to fully fill the gap with the thermally conductive insulating material through the first groove to form an integrated low thermal resistance thermal conductive layer.

[0084] In this embodiment, the thermally conductive insulating material can be epoxy glue or modified silica gel, and the thermal conductivity is generally 1.5 to 5 W / (m·K), which is much higher than the thermal conductivity of air (about 0.026 W / (m·K)). This high thermal conductivity and insulating material not only replaces air, insulating paint and insulating powder, but also replaces the insulating property requirements of insulating paper, which can further reduce the application of insulating paper, or use other materials instead of insulating paper.

[0085] Specifically, the negative pressure potting process includes: placing the stator assembly and the inner shell assembly in a vacuum environment, evacuating to -0.09MPa, and maintaining for 30 minutes to remove the air in the assembly; then injecting the degassed thermally conductive insulating material into the vacuum environment to fully infiltrate the surface of the assembly; finally, restoring normal pressure and using external atmospheric pressure to assist the thermally conductive insulating material to further penetrate into the gap.

[0086] The normal pressure potting process includes: taking out the components that have undergone negative pressure potting, and performing secondary potting in a normal pressure environment to fill the tiny gaps that may still exist; after the thermal conductive insulating material is semi-cured, removing excess material on the surface; and finally placing the components in an oven for curing at a temperature of 80°C for 4 hours.

[0087] By combining this method of multiple negative pressure potting with normal pressure potting, it can be ensured that the thermally conductive insulating material fully fills all gaps to form a bubble-free, high-density, low-thermal resistance thermal conductive layer, thereby maximizing the heat dissipation effect.

[0088] In some embodiments of the present invention, there are a plurality of first grooves, which can be arranged evenly or in areas where heat is concentrated.

[0089] In some embodiments of the present invention, the first groove extends along the axial direction of the inner shell from the bottom of the crown end to the bottom of the welding end.

[0090] In some embodiments of the present invention, the cross-sectional shape of the first groove is a circle, an isosceles triangle, an equilateral triangle or an isosceles trapezoid.

[0091] Example 6

[0092] This embodiment is an improvement on embodiment 5. When designing the inner shell, in addition to the first groove, a fixing groove is also provided on the inner wall of the inner shell. The design of the fixing groove is as described in embodiment 2, including a plurality of welding end fixing grooves provided at the welding end and a crown end fixing groove provided at the crown end.

[0093] During the potting process, the thermal insulation material of the low thermal resistance thermal conductive layer will penetrate into the fixing groove, increasing the heat exchange area between the low thermal resistance thermal conductive layer and the inner shell. This design not only improves the heat dissipation efficiency, but also strengthens the mechanical connection between the low thermal resistance thermal conductive layer and the inner shell, improving the stability and reliability of the overall structure.

[0094] Example 7

[0095] This embodiment is a further improvement of Embodiment 5 or 6. When designing the inner casing, an end surface water channel is further provided on the end surface of the inner casing located at the welding end of the stator assembly to increase the effective heat exchange area with the low thermal resistance heat conducting layer and to cool the bearing.

[0096] The design of the end water channel is as described in Example 4, and its water inlet is connected to the water inlet of the cooling water channel, and the water outlet is connected to the water outlet of the cooling water channel, forming a complete water circulation system. This design increases the effective heat exchange area, especially strengthens the cooling of the bearing area, prolongs the service life of the bearing, and improves the reliability of the range extender.

[0097] Example 8

[0098] This embodiment mainly optimizes the design of the first groove and the fixing groove.

[0099] In a specific embodiment of the present invention, the cross-sectional shape of the first groove 41 is an equilateral triangle with a side length of 1.5 mm. After heat conduction simulation analysis, the equilateral triangle groove has a better capillary penetration effect, which can improve the filling efficiency while ensuring the structural strength. The number of the first grooves 41 is 8, which are evenly distributed along the circumference of the inner shell, and each groove is spaced 45° apart. This even distribution ensures that the thermally conductive insulating material can more evenly fill the gap between the entire stator assembly and the inner shell.

[0100] In a specific embodiment of the present invention, the cross-sectional shape of the fixing groove is also an equilateral triangle with a side length of 1.5 mm. The number of the welding end fixing grooves is 8, and the number of the crown end fixing grooves is also 8, which are evenly distributed on the inner wall of the inner shell, but their positions are staggered with the first groove 41 to ensure structural strength. The height of the welding end fixing groove 44 is equal to the height of the welding end winding plus 8 mm, and the height of the crown end fixing groove 45 is equal to the height of the crown end winding plus 8 mm.

[0101] In a specific embodiment of the present invention, the fixing groove adopts an isosceles trapezoidal cross section, with an upper base length of 2 mm, a lower base length of 1 mm, and a height of 1.5 mm. The number of the welding end fixing grooves and the crown end fixing grooves is 12, evenly distributed along the circumference.

[0102] Example 9

[0103] This embodiment provides an optimized range extender cooling structure for high-speed operation. When running at high speed, the heat generated by the bearings and rotors increases significantly, requiring a more effective heat dissipation solution.

[0104] In this embodiment, the end surface water channel design of the inner shell is optimized. The end surface water channel adopts a double helix structure to form two parallel cooling channels, one of which is mainly responsible for cooling the low thermal resistance heat conduction layer, and the other is mainly responsible for cooling the bearing area. Through this design, targeted cooling can be performed for different heat sources to improve heat dissipation efficiency.

[0105] The cooling water channel adopts a variable cross-section design. In the hot spot area, the cross-sectional area of ​​the water channel is increased, the flow rate is reduced, and the heat exchange time is extended; in the non-hot spot area, the cross-sectional area of ​​the water channel is reduced, the flow rate is increased, and the coolant circulation is accelerated. This variable cross-section design can be optimized according to the heat distribution to achieve precise cooling.

[0106] The first groove of this embodiment adopts a composite design, with part of the cross section being a circle with a diameter of 1.5 mm and part of the cross section being an equilateral triangle with a side length of 1.5 mm. Grooves of different shapes are distributed in different positions, and the most suitable groove shape is selected according to the gap characteristics of each area to achieve the best filling effect.

[0107] The fixing groove also adopts a composite design, and different shapes and sizes are selected according to the stress and heat dissipation requirements of different positions. The height of the welding end fixing groove is equal to the welding end winding height plus 10 mm, and the height of the crown end fixing groove is equal to the crown end winding height plus 10 mm, maximizing the heat exchange area.

[0108] The thermally conductive insulating material used in this embodiment is a special high thermal conductivity epoxy resin with a thermal conductivity of 1.8W / (m·K) and an insulation strength of up to 20kV / mm, which can meet the safety requirements of high-speed and high-voltage operation.

[0109] Through these optimized designs, when the range extender of this embodiment runs at a high speed of 20,000 rpm, the temperature rise is controlled within 85°C, which is far lower than the temperature resistance level of the insulating material, ensuring the safety and reliability of high-speed operation.

[0110] Example 10

[0111] This embodiment provides a range extender, comprising the cooling structure as described in any one of the above embodiments 1 to 4. The range extender has good heat dissipation performance, can operate stably for a long time at a high power, and is suitable for various new energy vehicles.

[0112] like Figure 2 As shown, the range extender includes a range extender housing 5, an inner housing 4, a stator assembly 3, a rotor assembly 1, a low thermal resistance heat conductive layer 2 and other components not shown (such as bearings, end covers, etc.). The inner housing 4 is placed between the stator assembly 3 and the range extender housing 5, and its outer wall is provided with a cooling water channel, and its inner wall is provided with a first groove and a fixing groove. The low thermal resistance heat conductive layer 2 is filled with a heat conductive insulating material in the crown end, welding end, the gap between the winding and the iron core of the stator assembly 3, and the first groove and the fixing groove to form an integrated structure.

[0113] The cooling water flows between the outer wall of the inner shell 4 and the inner wall of the range extender shell 5 through the cooling water channel and the end surface water channel to take away the heat. The low thermal resistance heat conductive layer 2 efficiently transfers the heat generated by the winding and the core to the inner shell 4, which is then taken away by the cooling water, achieving efficient heat dissipation.

[0114] Compared with traditional range extenders, this range extender has the following advantages:

[0115] 1. High heat dissipation efficiency, can run stably at high power for a long time;

[0116] 2. Small size, light weight, high power density and torque density;

[0117] 3. Low production cost, eliminating the two processes of insulating paint dripping and insulating powder coating, saving materials and working hours;

[0118] 4. High reliability and long service life, especially significant cooling effect on bearings.

[0119] Embodiment 11

[0120] This embodiment provides a vehicle, including the range extender as described in Embodiment 10. The vehicle may be a pure electric vehicle, a range-extended electric vehicle, or a hybrid electric vehicle.

[0121] Example 12

[0122] This embodiment is an optimized solution for the design of the first groove. In this embodiment, the first groove not only extends from the bottom of the crown end to the bottom of the welding end along the axial direction, but is also evenly distributed in the circumferential direction to form a grid-like structure.

[0123] Specifically, the first groove includes an axial groove and a circumferential groove. The axial groove extends along the axial direction of the inner shell, and the circumferential groove extends along the circumference of the inner shell, and the two intersect to form a grid-like structure. This design further increases the penetration area of ​​the thermally conductive insulating material, so that the heat exchange area between the low thermal resistance thermal conductive layer and the inner shell is larger, and the heat dissipation efficiency is higher.

[0124] In practical applications, the number of axial grooves may be 8 to 16, and the number of circumferential grooves may be 4 to 8. The specific number may be adjusted according to the size of the inner shell and the heat dissipation requirements.

[0125] In summary, the range extender cooling structure provided by the present invention forms an integrated low thermal resistance heat conducting layer by setting an inner shell between the stator assembly and the range extender shell, setting a first groove on the inner wall of the inner shell, and filling the crown end, welding end and the gap between the winding and the core of the stator assembly with a heat conductive insulating material, thereby significantly improving the heat dissipation efficiency. At the same time, by designing fixed grooves and end face water channels on the inner shell, the heat exchange area is further increased, and the heat dissipation efficiency is improved. The cooling structure of the present invention not only has high heat dissipation efficiency, but also has the advantages of small size, light weight, and low cost, which is of great significance for improving the power density and reliability of the range extender.

[0126] Those skilled in the art will readily appreciate that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, replacements, improvements, etc. made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A range extender cooling structure, characterized in that: include: An inner housing is placed between the stator assembly and the range extender housing; The low thermal resistance heat-conducting layer is filled with heat-conducting insulating materials at the crown end, welding end and the gap between the winding and the core of the stator assembly to form an integrated structure; The outer wall of the inner shell is provided with a cooling water channel; the inner wall of the inner shell is provided with a first groove for allowing the heat-conducting insulating material to penetrate into the gap.

2. The range extender cooling structure according to claim 1, characterized in that: The inner wall of the inner shell is also provided with a fixing groove; the low thermal resistance heat conductive layer penetrates into the fixing groove to increase the heat exchange area between the low thermal resistance heat conductive layer and the inner shell.

3. The range extender cooling structure according to claim 2, characterized in that: The fixing grooves include a plurality of welding end fixing grooves arranged at the welding end and a plurality of crown end fixing grooves arranged at the crown end.

4. The range extender cooling structure according to claim 1, characterized in that: There are multiple first grooves, which can be evenly arranged or arranged in the area where heat is concentrated; the first groove extends from the bottom of the crown end to the bottom of the welding end along the axial direction of the inner shell.

5. The range extender cooling structure according to claim 1, characterized in that: At least one end surface of the inner shell is provided with an end surface water channel for increasing the effective heat exchange area between the inner shell and the low thermal resistance heat conducting layer and cooling the bearing.

6. A method for manufacturing a range extender cooling structure, characterized in that: include: An inner housing is designed, wherein the outer wall of the inner housing is provided with a cooling water channel, and the inner wall of the inner housing is provided with a first groove; the inner housing is installed between the stator assembly and the range extender housing; The crown end, welding end and gap between the winding and the core of the stator assembly are filled with thermally conductive insulating material. Multiple negative pressure potting is combined with normal pressure potting to fully fill the gap with the thermally conductive insulating material through the first groove to form an integrated low thermal resistance thermal conductive layer.

7. The method for manufacturing a range extender cooling structure according to claim 6, characterized in that: When designing the inner shell, a fixing groove is further provided on the inner wall of the inner shell; the low thermal resistance heat conductive layer penetrates into the fixing groove to increase the heat exchange area between the low thermal resistance heat conductive layer and the inner shell.

8. The method for manufacturing a range extender cooling structure according to claim 6, characterized in that: When designing the inner shell, an end surface water channel is provided on the end surface of the inner shell located at the welding end of the stator assembly, so as to increase the effective heat exchange area between the inner shell and the low thermal resistance heat conducting layer and cool the bearing.

9. A range extender, comprising the cooling structure according to any one of claims 1 to 5.

10. A vehicle comprising the range extender according to claim 9.

Images