Heat dissipation unit and busbar assembly

Abstract

The utility model provides a heat dissipation unit and a busbar assembly. The heat dissipation unit (1) comprises a heat conduction electric insulation coating (11) and a heat conduction element (12), the heat conduction electric insulation coating (11) is at least partially coated on one side of the heat conduction element (12), and the heat conduction electric insulation coating (11) is made of inorganic non-metal materials. The heat dissipation function is provided for the to-be-cooled element, and meanwhile the electric insulation protection effect is achieved.

Description

Technical Field

[0001] This disclosure relates to the field of heat dissipation, and more specifically, to heat dissipation units and bus assemblies. Background Technology

[0002] This section aims to provide background information relevant to understanding the various techniques described herein. As the title of this section implies, this is a discussion of related techniques that should in no way imply that they are necessarily prior art. Therefore, it should be understood that any statement in this section should be read in this context, rather than as an admission of any prior art.

[0003] In electric drive products, large currents frequently occur in busbars. To protect heat-sensitive components, cooling methods are typically employed to cool the busbars. In some embodiments known to the applicant, a busbar + thermal pad + insulating paper + housing approach is used. The thermal pad's primary function is to fill gaps and transfer heat from the busbar to the housing, while the insulating paper provides electrical insulation. In other embodiments, a busbar + thermal pad + housing approach is used. In these, the thermal pad has a larger size to meet creepage distance requirements. However, this approach carries the risk that the uncompressed thermal pad may crack under vibration loads. Furthermore, comparing the thermal conductivity of these materials, the insulating paper has a low thermal conductivity, resulting in poor heat dissipation performance. Utility Model Content

[0004] Depending on the specifics, the purpose of this disclosure is to provide heat dissipation for the heat-dissipating component while also providing electrical insulation protection.

[0005] Furthermore, the purpose of this disclosure is to solve or at least alleviate one or more problems existing in the prior art.

[0006] This disclosure addresses the aforementioned problems by providing a heat dissipation unit and a bus assembly. Specifically, according to one aspect of this disclosure, the following is provided:

[0007] A heat dissipation unit, wherein the heat dissipation unit includes a thermally conductive and electrically insulating coating and a thermally conductive element, the thermally conductive and electrically insulating coating being at least partially coated on one side of the thermally conductive element, and the thermally conductive and electrically insulating coating being composed of an inorganic non-metallic material.

[0008] Alternatively, according to one embodiment of this disclosure, the thermally conductive and electrically insulating coating extends beyond the thermally conductive element, such that creepage current on the surface of the thermally conductive and electrically insulating coating can be blocked.

[0009] Alternatively, according to one embodiment of this disclosure, the inorganic non-metallic material includes graphene or alumina ceramic.

[0010] Alternatively, according to one embodiment of this disclosure, when the inorganic non-metallic material includes graphene, the thermally conductive and electrically insulating coating is formed by electromagnetic deposition of a graphene and nano-ceramic suspension.

[0011] Optionally, according to one embodiment of this disclosure, the thermally conductive element is capable of absorbing the installation tolerance of the element to be cooled, and the thermally conductive element is a thermally conductive pad, which is made of silicone, polyurethane or acrylate.

[0012] According to another aspect of this disclosure, a bus assembly is provided, wherein the bus assembly includes any of the above-described heat dissipation units, a bus, and a housing, the bus being disposed on the housing via the heat dissipation unit, and the thermally conductive element being used to absorb the installation tolerance between the bus and the housing.

[0013] Optionally, according to one embodiment of this disclosure, the thermally conductive and electrically insulating coating is applied between the thermally conductive element and the housing, and / or the thermally conductive and electrically insulating coating is applied between the busbar and the thermally conductive element.

[0014] Optionally, according to one embodiment of the present disclosure, the bus includes an assembly portion, the bus is assembled to the housing via the assembly portion, and the thermally conductive and electrically insulating coating is also applied to the side surface and outer end face of the assembly portion.

[0015] Alternatively, according to one embodiment of the present disclosure, the housing is configured with a boss, the heat-conducting element is disposed on the boss, and the boss extends beyond the heat-conducting element.

[0016] Optionally, according to one embodiment of this disclosure, the boss is configured with ribs, which are used to limit the mounting position of the heat-conducting element. Attached Figure Description

[0017] Referring to the accompanying drawings, the above and other features of this disclosure will become apparent, wherein,

[0018] Figure 1 A perspective view of a bus assembly according to the present disclosure is shown;

[0019] Figure 2 A top view of a bus assembly according to the present disclosure is shown;

[0020] Figure 3 A cross-sectional view of a bus assembly in the heat dissipation unit region according to the present disclosure is shown;

[0021] Figure 4 A perspective view showing the interaction between a bus and a heat dissipation unit according to the present disclosure is shown; and

[0022] Figure 5 A bottom view of a bus and heat dissipation unit according to the present disclosure is shown. Detailed Implementation

[0023] It is readily understood that, based on the technical solutions of this disclosure, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of this disclosure. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solutions of this disclosure and should not be considered as the entirety of this disclosure or as limitations or restrictions on the technical solutions of this disclosure.

[0024] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the structures shown in the accompanying drawings. These are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive. Furthermore, the terms "first," "second," "third," and similar expressions are used for descriptive and distinguishing purposes only and should not be construed as indicating or implying the relative importance of the corresponding components.

[0025] Figure 1 A perspective view of a bus assembly according to the present disclosure is shown; Figure 2 A top view of a bus assembly according to this disclosure is shown; and Figure 3 A cross-sectional view of a bus assembly in the heat dissipation unit region according to the present disclosure is shown.

[0026] This disclosure relates to a heat dissipation unit 1, wherein the heat dissipation unit 1 includes a thermally conductive and electrically insulating coating 11 and a thermally conductive element 12, the thermally conductive and electrically insulating coating 11 being at least partially coated on one side of the thermally conductive element 12, and the thermally conductive and electrically insulating coating 11 being made of an inorganic non-metallic material.

[0027] It should be understood that the thermally conductive and electrically insulating coating achieves both thermal conductivity and electrical insulation functions. Together with the thermally conductive element, it enables the conduction and dissipation of heat from the element to be cooled. Furthermore, the coating insulates against any current that may exist in the element to be cooled, ensuring electrical safety.

[0028] The component to be cooled can refer to the heat-generating device itself, or an intermediate component that also needs heat dissipation due to direct or indirect connection to the heat-generating device. For example, in the application of electric drive systems in vehicles, the heat-generating device is a capacitor or inductor, and the intermediate component is a busbar (e.g., a copper busbar) used for carrying current and dissipating heat, which itself also needs to be treated as a component to be cooled. The use of inorganic non-metallic materials, especially compared to insulating paper made of organic fibers, offers the feasibility of achieving a high thermal conductivity, ensuring that heat can be quickly conducted from the heat source to the heat dissipation unit, reducing the operating temperature of the component to be cooled. At the same time, this material also offers the feasibility of having high resistivity, effectively preventing current leakage and protecting circuit safety. Even under high temperature or high voltage environments, the coating can maintain stable insulation performance.

[0029] For example, the thermally conductive element is constructed as a cuboid, which is a thin sheet (i.e., its thickness is less than its length or width) and is placed under the element to be cooled, thus achieving thermal conductivity in a cost-effective manner. Therefore, a coating can be applied to either the upper or lower surface of the thermally conductive element.

[0030] It is evident that the heat dissipation unit can simultaneously perform multiple functions of heat conduction and electrical insulation, reducing the number of components and simplifying the assembly process while maintaining or improving functionality.

[0031] Specifically, in some embodiments, the inorganic non-metallic material includes graphene or alumina ceramic. Regarding graphene, the applicant recognizes that graphene coatings possess excellent electrical insulation properties. Moreover, particularly in the vertical direction, its thermal conductivity is, for example, 15–20 W / (m·K), higher than that of insulating paper films, naturally resulting in higher heat dissipation efficiency. Therefore, graphene coatings have a positive effect on the thermal performance of heat dissipation components, rapidly dissipating heat and preventing performance degradation or component failure caused by localized overheating. In addition, graphene is typically thin, meaning the thickness of the graphene heat dissipation coating is controllable, allowing for high heat flux requirements to be met without the need for multiple layers, thus reducing interfacial thermal resistance.

[0032] Alumina ceramics possess characteristics such as high temperature resistance, high hardness, oxidation resistance, and corrosion resistance. They also have a low coefficient of thermal expansion and low high-frequency losses, making them particularly suitable for the insulation protection of power electronic devices. Furthermore, the polycrystalline structure of ceramics enables multidirectional heat dissipation, optimizing heat flow distribution.

[0033] Besides the two materials mentioned above, those skilled in the art can also consider other materials to achieve the desired effect. For example, boron nitride, aluminum nitride, diamond, etc., can be selected based on factors such as cost, expected effect, and layout space.

[0034] In some embodiments of this disclosure, the thermally conductive element 12 can absorb the installation tolerances of the component to be cooled. The thermally conductive element 12 is a thermally conductive pad, which is made of silicone, polyurethane, or acrylate. This technical solution endows the thermally conductive pad with flexibility, enabling it to adapt to irregular surfaces, reducing the requirements for processing and installation precision. It can reduce thermal resistance by filling gaps, reducing hot spot temperature rise, and ensuring stable contact and heat transfer between the heat dissipation unit and the component to be cooled. The thermally conductive pad's elastic compression properties can also reduce mechanical stress caused by thermal expansion and contraction or vibration. Furthermore, when the thermally conductive pad is made of silicone, it can use silicone as the base material and add fillers such as alumina and silicon nitride. Thus, through the construction of a thermally conductive network, enhanced insulation performance, improved mechanical properties, and matching of thermal expansion coefficients, the thermally conductive pad achieves comprehensive optimization in terms of heat dissipation efficiency, reliability, and durability. In addition, the technical solution also specifies that the heat-conducting element can absorb the installation tolerance of the element to be cooled, thereby ensuring that the element to be cooled can be installed in a suitable manner, and that the stable contact of the heat dissipation interface and the heat dissipation and electrical insulation performance can be guaranteed.

[0035] Regarding the absorption tolerance characteristics of thermally conductive elements, those skilled in the art know that such elements can be constructed in various ways. For example, tolerance absorption can be achieved by designing the shape of the thermally conductive element or by utilizing the elasticity of the element itself. Thus, stable contact between the heat dissipation unit and the element to be cooled can optimize the heat conduction path, reduce thermal resistance, and further improve heat dissipation efficiency.

[0036] It is evident that the heat dissipation unit can simultaneously perform multiple functions such as heat conduction, electrical insulation, and tolerance compensation, reducing the number of components and simplifying the assembly process while maintaining or improving functionality.

[0037] Figure 4 A perspective view showing the interaction between a bus and a heat dissipation unit according to the present disclosure is shown; and Figure 5 A bottom view of a bus and heat dissipation unit according to the present disclosure is shown.

[0038] The thermally conductive and electrically insulating coating 11 extends beyond the thermally conductive element 12, thereby blocking creepage current on the surface of the thermally conductive and electrically insulating coating 11.

[0039] Those skilled in the art should understand that creepage current refers to the current flowing on the surface of an insulator. This technical solution designs the coating dimensions to block the flow of this current on the insulator surface. The specific dimensional design can depend on the coating material and the corresponding creepage distance requirements. This oversized design also maximizes the heat dissipation area, accelerating heat radiation and convection to the environment and improving overall heat dissipation efficiency. Those skilled in the art can consider determining the creepage distance based on the material's Comparative Tracking Index (CTI), voltage, and foreign object size. For example, in applications with 1200V, Class I materials, and two 1.2mm conductive foreign objects, the creepage distance is greater than 5.9mm.

[0040] by Figure 3 Taking the design as an example, creepage begins at the contact edge between the heat-dissipating element and the coating. Since the coating is larger than the heat-conducting element, the current can terminate on the surface of the coating. Similarly, if the coating is applied between the heat-conducting element and the housing, the current can still terminate on the surface of the coating, starting from the contact edge between the heat-conducting element and the coating. Thus, the extended portion of the coating forms an "electrically insulating barrier".

[0041] In this regard, it should also be understood that the coating can extend beyond the heat-conducting element in any direction, so that the coating can provide a certain creepage distance for blocking current. For example, the coating can extend outward beyond the heat-conducting element at least on one side of the heat-conducting element in a plane perpendicular to the thickness direction of the heat-conducting element, or it can extend in the thickness direction of the heat-conducting element, and so on.

[0042] Furthermore, when the inorganic non-metallic material includes graphene, the thermally conductive and electrically insulating coating 11 is formed by electromagnetic deposition of a graphene and nano-ceramic suspension. Those skilled in the art should understand the specific implementation of electromagnetic deposition. Exemplarily, electromagnetic deposition includes applying an external magnetic field and magnetizing the suspended medium, such as graphene and nano-ceramic particles, to form a controllable nano-magnetized ion suspension. The coating formed by electromagnetic deposition is characterized by high thermal conductivity and heat dissipation, corrosion resistance and pressure resistance, and precise controllable coating thickness. In summary, the coating is formed by electromagnetic deposition after graphene is dispersed and doped with insulating materials.

[0043] In particular, by controlling the ordered arrangement of graphene sheets through a magnetic field, thermal conductivity can be further improved, and a high-density ion-level nano-crosslinked structure can be formed, resulting in a high coating density. This technical solution also achieves the synergistic effect of graphene and nanoceramics, where graphene constructs a thermally conductive network and nanoceramics form an insulating barrier, achieving compatibility between thermal conductivity and insulation, reducing interfacial thermal resistance, and improving overall performance.

[0044] According to another aspect of this disclosure, a bus assembly 100 is provided, wherein the bus assembly 100 includes any of the above-described heat dissipation unit 1, a bus 2, and a housing 3, the bus 2 being arranged on the housing 3 via the heat dissipation unit 1, and the thermally conductive element 12 being used to absorb the installation tolerance between the bus 2 and the housing 3.

[0045] Therefore, the bus assembly disclosed herein can inherit various implementation methods and corresponding technical effects of the heat dissipation unit, which will not be elaborated here.

[0046] According to this technical solution, the busbar can be understood as an intermediate component that is electrically connected to heat-generating devices (such as capacitors and inductors). During operation, it dissipates heat through a heat dissipation element, which also ensures electrical insulation, giving the housing electrical safety and protecting personnel's electrical safety. During assembly, the heat-conducting element, through its shape or material design, can absorb installation tolerances and fill gaps between the busbar and the housing, ensuring the busbar and housing have the intended installation position. In particular, it ensures no air gap between them and makes the connection between the heat dissipation unit and the housing reliable, reducing thermal resistance and thus guaranteeing the expected heat dissipation and electrical insulation effects.

[0047] It is also understood that this disclosure does not impose any limitation on the number of components. For example, one or more busbars may be arranged inside the housing, or the busbars may be equipped with one or more heat dissipation units, or the busbars may have multiple connection terminals 22 for direct or indirect connection to heat-generating devices, so as to improve space utilization or achieve multiple heat management.

[0048] Regarding the layout of the coating, it is feasible for the thermally conductive and electrically insulating coating 11 to be applied between the thermally conductive element 12 and the housing 3, and / or for the thermally conductive and electrically insulating coating 11 to be applied between the busbar 2 and the thermally conductive element 12.

[0049] In other words, the coating layout can be flexibly selected and adjusted according to the available space, while still achieving the desired thermal conductivity and electrical insulation. Simultaneous coating can also be performed to achieve further performance optimization.

[0050] When the coating is disposed between the heat-conducting element and the housing, the coating can be in the shape of a film. When the coating is disposed between the heat-conducting element and the busbar, the coating can be a film, or further coating can be applied on this basis.

[0051] That is, the busbar 2 includes an assembly part 21, the busbar 2 is assembled to the housing 3 via the assembly part 21, and the thermally conductive and electrically insulating coating 11 is also coated on the side and outer end face of the assembly part 21.

[0052] In this design, the coating is applied using the space provided by the structure of the bus assembly section itself, thus achieving good space utilization without requiring additional space.

[0053] Depending on the specific size or shape of the assembly, the coating can be applied to its sides and outer end face (top surface), maximizing the creepage distance provided by the coating by utilizing the structure of the assembly, or other forms of coating can be applied depending on its specific shape. Here, the assembly is exemplarily located at the bottom of the busbar and has a cuboid shape, which facilitates coating application and creepage distance calculation. In addition, this design also provides some protection for the assembly. For example, the dense packing of nano-ceramic particles in the coating can block the penetration of corrosive media.

[0054] Combination Figures 1 to 3 It is also evident that the housing 3 is provided with a boss 31, on which the heat-conducting element 12 is arranged, and the boss 31 extends beyond the heat-conducting element 12, for example, on a plane perpendicular to the thickness direction of the heat-conducting element, at least on one side of the heat-conducting element.

[0055] As a localized thickening structure within the housing, the boss can form a "thermal channel," directing the heat absorbed by the heat dissipation unit rapidly and specifically to the boss, providing directionality for subsequent heat dissipation or other measures. The boss can also be specifically designed for heat dissipation, such as controlling its surface roughness to increase the actual contact area with the heat dissipation unit and reduce contact thermal resistance. Furthermore, it is conceivable to design bosses in various sizes to accommodate different types of busbars.

[0056] Furthermore, ribs can be provided on the boss to cooperate with the heat-conducting element. Specifically, the ribs can restrict the assembly position of the heat-conducting element, preventing inaccurate alignment of the heat dissipation position during assembly.

[0057] This disclosure also relates to an electric drive system for a vehicle, wherein the electric drive system includes any of the bus assembly 100 described above.

[0058] Therefore, the electric drive system of the vehicle disclosed herein inherits various implementation methods and corresponding technical effects of the bus assembly, which will not be elaborated further here. However, it should be understood that the vehicle includes new energy vehicles, such as hybrid electric vehicles, pure electric vehicles, and (hydrogen) fuel cell electric vehicles.

[0059] It should be understood that all the above preferred embodiments are exemplary and not restrictive, and various modifications or variations made by those skilled in the art to the specific embodiments described above under the concept of this disclosure should be within the legal protection scope of this disclosure.

Claims

1. A heat dissipation unit (1), characterized in that, The heat dissipation unit (1) includes a thermally conductive and electrically insulating coating (11) and a thermally conductive element (12). The thermally conductive and electrically insulating coating (11) is at least partially coated on one side of the thermally conductive element (12). The thermally conductive and electrically insulating coating (11) is made of inorganic non-metallic material.

2. The heat dissipation unit (1) according to claim 1, characterized in that, The thermally conductive and electrically insulating coating (11) extends beyond the thermally conductive element (12), such that creepage current on the surface of the thermally conductive and electrically insulating coating (11) can be blocked.

3. The heat dissipation unit (1) according to claim 1, characterized in that, The inorganic non-metallic materials include graphene or alumina ceramics.

4. The heat dissipation unit (1) according to claim 3, characterized in that, In the case where the inorganic non-metallic material includes graphene, the thermally conductive and electrically insulating coating (11) is formed by electromagnetic deposition of graphene and nano-ceramic suspension.

5. The heat dissipation unit (1) according to claim 1, characterized in that, The thermally conductive element (12) can absorb the installation tolerance of the element to be cooled. The thermally conductive element (12) is a thermal pad, which is made of silicone, polyurethane or acrylate.

6. A busbar assembly (100), characterized in that, The bus assembly (100) includes a heat dissipation unit (1), a bus (2), and a housing (3) according to any one of claims 1 to 5, wherein the bus (2) is arranged on the housing (3) via the heat dissipation unit (1), and the thermally conductive element (12) is used to absorb the installation tolerance between the bus (2) and the housing (3).

7. The bus assembly (100) according to claim 6, characterized in that, The thermally conductive and electrically insulating coating (11) is applied between the thermally conductive element (12) and the housing (3), and / or the thermally conductive and electrically insulating coating (11) is applied between the busbar (2) and the thermally conductive element (12).

8. The bus assembly (100) according to claim 7, characterized in that, The busbar (2) includes an assembly part (21), which is assembled to the housing (3) via the assembly part (21). The thermally conductive and electrically insulating coating (11) is also coated on the side and outer end face of the assembly part (21).

9. The bus assembly (100) according to claim 6, characterized in that, The housing (3) is provided with a boss (31), the heat-conducting element (12) is arranged on the boss (31), and the boss (31) extends beyond the heat-conducting element (12).

10. The bus assembly (100) according to claim 9, characterized in that, The boss (31) is constructed with ribs, which are used to limit the installation position of the heat-conducting element (12).

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