Copper-aluminum composite busbar and power electronic unit
By designing a copper-aluminum composite busbar and using an integrated potting structure, the problems of brittle oxides during welding and the defects of separate installations are solved, enabling efficient welding, low cost, and highly integrated busbar applications, thereby improving the performance of electric drive systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2026-03-27
AI Technical Summary
Existing copper-aluminum composite busbars are prone to generating brittle oxides during welding, resulting in reduced connection quality and strength, as well as low welding efficiency and high cost. In the power electronics unit of the electric drive system, the filters and capacitors are installed separately, occupying a large space, with low integration and poor heat dissipation.
The design adopts a copper-aluminum composite bus, in which the connection terminals are made of aluminum and are connected to other components by laser welding. A nickel sheet is placed on the connection terminals as an intermediate layer to isolate the copper and aluminum, eliminating the separate installation method and encapsulating the filter and capacitor in a metal shell.
It avoids the formation of brittle copper and aluminum oxides, improves welding quality and strength, reduces costs and weight, increases production efficiency and integration, and enhances heat dissipation and service life.
Smart Images
Figure CN224053584U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the busbar technical field, specifically provide a copper aluminum composite busbar and power electronic unit. BACKGROUND
[0002] At present, the busbar material used for conducting electricity in capacitor assembly and filter assembly is all high-purity oxygen-free copper material, the advantages of copper material are high conductivity, good heat dissipation performance and good ductility, but its cost is very high and the density is relatively large, compared with copper material and aluminum material of the same size, the cost and weight of aluminum material are about one third of copper material, so the use of aluminum material is significant in reducing the cost and weight of the product, but the conductivity of aluminum material is slightly inferior to that of copper material, therefore, in order to balance the conductivity and the weight and cost of the busbar, the copper aluminum composite busbar can be considered, but when the busbar is welded with other elements, since the busbar itself has copper and aluminum materials, some welding methods that make the metal melt may cause copper aluminum brittle oxide between copper and aluminum in the welding process, the existence of brittle oxide will reduce the connection quality and connection strength, therefore, the copper aluminum composite busbar is inconvenient to be directly welded with other element busbars in the form of melting, the connection method needs to be carefully considered, and generally, the welding method is tin soldering or ultrasonic welding or other non-melting metal welding methods, these welding methods are low in efficiency or high in equipment cost, and the welding quality is difficult to detect, so it is not conducive to the promotion and use of the copper aluminum composite busbar.
[0003] The installation structure form of the filter and capacitor assembly in the power electronic unit (PEU) of the electric drive system is often in the form of split type installation, that is, the capacitor and the filter are separate parts, and then are installed in the interior of the PEU shell, and the disadvantage of the installation method is that the capacitor and the filter need to be designed separately and have large outer envelopes, the capacitor and the filter occupy a large space in the PEU shell during installation, and more fixing structures need to be designed, the integration degree of the power electronic unit is low, the assembly process line is long, and the production efficiency is low, and the existing capacitor and filter assembly shells are mostly made of plastic material, and since the heat dissipation effect of the plastic material is poor, the heat dissipation effect of the capacitor and the filter is also poor.
[0004] Correspondingly, there is a need in the art for a new technical solution to solve the above problems. UTILITY MODEL CONTENT
[0005] The utility model aims at solving above-mentioned technical problem, namely solves the problem that the existing copper-aluminum composite busbar is easy to produce brittle oxide when welding. For this purpose, the utility model provides a kind of copper-aluminum composite busbar, the busbar includes: aluminum layer, the aluminum layer includes the upper surface and lower surface opposite each other along first direction;First copper layer, the first copper layer is arranged on the upper surface;Second copper layer, the second copper layer is arranged on the lower surface;The part of the aluminum layer along second direction is protruding from the first copper layer and the second copper layer is connection terminal.
[0006] In the above embodiment with busbar, the thickness of the first copper layer and the thickness of the second copper layer are the same.
[0007] In the above embodiment with busbar, the thickness of the aluminum layer is greater than the thickness of the first copper layer;The thickness of the aluminum layer is greater than the thickness of the second copper layer.
[0008] In the above embodiment with busbar, the aluminum layer, the first copper layer and the second copper layer are integrally formed.
[0009] In the above embodiment with busbar, the busbar further includes: connecting sheet, the connecting sheet is arranged on the end of the connection terminal away from the first copper layer along second direction.
[0010] The utility model also includes: a power electronic unit, including filter and capacitor, the busbar in the filter and the capacitor is the busbar of any one described above.
[0011] In the above embodiment with power electronic unit, the power electronic unit further includes: shell, the filter and the capacitor are arranged in the shell, and the filter and the capacitor are filled with potting adhesive between the shell.
[0012] In the above embodiment with power electronic unit, the filter and the capacitor are arranged side by side in the shell.
[0013] In the above embodiment with power electronic unit, the power electronic unit further includes: power module, the power module is arranged above the filter and the capacitor;Printed circuit board assembly, the printed circuit board assembly is arranged above the power module.
[0014] In the above embodiment with power electronic unit, the shell is metal shell.
[0015] In the technical scheme, the connecting terminal protrudes from the first copper layer and the second copper layer, and the connecting terminal is made of only one kind of material, i.e. aluminum. In the case that the connecting terminal does not include other metal materials (e.g. copper), the copper-aluminum contained in the busbar itself will not produce copper-aluminum brittle oxide in the welding process. In the utility model, the connecting piece is arranged. When the copper-aluminum composite busbar in the utility model is connected with other elements, the connecting terminal at the end of the busbar only needs to be laser welded with the copper conductive terminal of other elements (e.g. power module) through the intermediate connecting piece (e.g. nickel piece). The connecting piece as the intermediate layer can effectively isolate aluminum and copper to prevent direct contact between the two, thereby avoiding the production of copper-aluminum brittle oxide between the connecting terminal and other elements in the welding process. The utility model solves the problem that the existing copper-aluminum composite busbar is prone to produce copper-aluminum brittle oxide in the welding process, improves the connection quality and connection strength of the busbar, enables the busbar to select more welding modes, reduces the welding cost while improving the production efficiency, guarantees the advantages of weight reduction and cost reduction brought by the copper-aluminum composite material, and facilitates the popularization and use of the copper-aluminum composite busbar. BRIEF DESCRIPTION OF DRAWINGS
[0016] The preferred embodiments of the utility model will be described below with reference to the drawings, in which:
[0017] Figure 1 is the cross-sectional view of the busbar in the utility model;
[0018] Figure 2 is the structural schematic view of the power electronic unit in the utility model.
[0019] In the drawings: 1, aluminum layer, 2, first copper layer, 3, second copper layer, 4, connecting terminal, 5, filter, 6, capacitor, 7, shell, 8, power module, 9, printed circuit board assembly, 10, connecting piece. DETAILED DESCRIPTION
[0020] The preferred embodiments of the utility model will be described below with reference to the drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the utility model, and are not used to limit the protection scope of the utility model. Those skilled in the art can adjust them as needed to adapt to specific application occasions. For example, although the description is combined with the filter and the capacitor, this is not restrictive, and those skilled in the art can apply the utility model to any other electronic device as needed, as long as the electronic device has a busbar.
[0021] It should be noted that in the description of this utility model, terms such as "upper," "lower," "left," "right," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the relevant device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, ordinal numbers such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0022] Furthermore, it should be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0023] Furthermore, in order to more clearly demonstrate the core technical solution of this utility model, the description of known structures such as filters and capacitors is omitted in the following description. However, this omission is only for the convenience of description and does not mean that filters and capacitors can be without these structures.
[0024] like Figure 1 As shown, this utility model proposes a busbar, including: an aluminum layer 1, the aluminum layer 1 including an upper surface and a lower surface opposite to each other along a first direction; a first copper layer 2, the first copper layer 2 being disposed on the upper surface; a second copper layer 3, the second copper layer 3 being disposed on the lower surface; and a connection terminal 4 being a portion of the aluminum layer 1 protruding from the first copper layer 2 and the second copper layer 3 along a second direction. Figure 1 In this diagram, the X direction represents the first direction, and the Y direction represents the second direction.
[0025] To address the issue of brittle copper and aluminum oxides easily forming during welding of existing copper-aluminum composite busbars, this embodiment improves the structure of the busbar. In this improvement, the connecting terminal 4 protrudes from the first copper layer 2 and the second copper layer 3. When connecting the busbar to other components, only the connecting terminal 4 needs to be welded to the other components. Since the connecting terminal 4 is part of the aluminum layer, it only contains aluminum. When the connecting terminal 4 does not contain other metal materials (such as copper), the copper and aluminum layers contained in the busbar itself will not generate brittle copper and aluminum oxides during welding. Because the busbar in this embodiment does not generate brittle oxides during welding, the problems of reduced connection quality and strength caused by brittle oxides are avoided. Therefore, more welding methods can be selected for welding the connecting terminal 4, improving production efficiency while reducing welding costs. This also ensures the significant weight reduction and cost reduction advantages brought by using copper-aluminum composite materials, facilitating the promotion and use of copper-aluminum composite busbars. For example, laser welding is used to weld the bus connection terminal 4 and other components. Compared with ultrasonic welding and soldering, laser welding is faster and cheaper.
[0026] The bus in this embodiment consists of a central aluminum layer 1 and two outer copper layers 2 and 3. During current conduction, the bus exhibits the skin effect, which indicates that when current passes through a conductor, the current density tends to concentrate on the surface of the conductor rather than being uniformly distributed throughout the entire conductor cross-section. This characteristic is crucial for bus design. Compared to copper, aluminum has lower conductivity. In this embodiment, the first copper layer 2 and the second copper layer 3 are disposed on the upper and lower surfaces of the aluminum layer 1. Due to the skin effect, the current is guided to the first copper layer 2 and the second copper layer 3. Copper not only has extremely high conductivity, significantly reducing resistance loss, but its excellent conductivity also reduces the impact of the inherent properties of aluminum on the bus's conductivity, ensuring normal bus operation. This embodiment reduces the weight and cost of the bus without affecting its performance.
[0027] It should be pointed out that, although Figure 1 The busbar shown has a stepped bend, but this is not a limitation of the present invention. Those skilled in the art can adjust the shape of the busbar without departing from the basic principles of the present invention, as long as it does not affect the busbar's performance and meets installation requirements. For example, using a busbar without bends, etc., does not deviate from the principles of the present invention and therefore falls within the protection scope of the present invention.
[0028] Further, in the embodiment, the thickness of the first copper layer 2 and the thickness of the second copper layer 3 are the same. It should be noted that, in order to make the resistance, tightening torque, and temperature rise degree of the busbar reach the level of the busbar of the existing copper material, the thickness ratio of the first copper layer 2 and the second copper layer 3 can be adjusted appropriately according to actual conditions by those skilled in the art.
[0029] Further, in order to reduce the weight and cost of the busbar as much as possible, in the embodiment, the thickness of the aluminum layer 1 is greater than the thickness of the first copper layer 2, and the thickness of the aluminum layer 1 is greater than the thickness of the second copper layer 3. In addition, the sum of the thickness of the first copper layer 2 and the thickness of the second copper layer 3 can be less than the thickness of the aluminum layer 1.
[0030] It should be noted that, in order to make the resistance, tightening torque, and temperature rise degree of the busbar reach the level of the busbar of the existing copper material, the thickness ratio of the first copper layer 2, the aluminum layer 1, and the second copper layer 3 can be adjusted appropriately according to actual conditions by those skilled in the art.
[0031] Further, in the embodiment, the aluminum layer 1, the first copper layer 2, and the second copper layer 3 are integrally formed. Unlike the traditional process of producing composite materials by hot rolling of two or more metal materials, the copper-aluminum composite material used in the busbar in the embodiment is in a semi-molten state during the compounding process, achieving 100% metallurgical compounding of copper and aluminum, better ductility, more bending resistance, and less layering. The copper-aluminum composite material can be processed on a continuous die to form the required structure, just like ordinary copper materials.
[0032] It should be noted that there are various processing methods for copper-aluminum composite materials in the prior art. Without deviating from the basic principles of the present application, those skilled in the art can use other processing methods, which do not deviate from the principles of the present application, and thus fall within the scope of protection of the present application.
[0033] Further, in the embodiment, the busbar further comprises a connecting piece 10, which is arranged on the side of the connecting terminal 4 away from the first copper layer 2 along the second direction. The connecting piece 10 is made of metal (for example, a nickel sheet), one end of the connecting terminal 4 away from the first copper layer 2 is welded to one end of the connecting piece 10, and the other end of the connecting piece 10 is used for welding to other elements.
[0034] Since the connecting terminal 4 is made of aluminum, in the process of welding the connecting terminal 4 with other elements (such as a power module), although the bus bar itself will not react between copper and aluminum, when the connecting terminal 4 is connected with the conductive row of the other element, the conductive row of the element may be made of copper, so the aluminum in the connecting terminal 4 and the conductive copper row in the other element may still react. In order to avoid this situation, facilitate the connection of the connecting terminal 4 with the other element, a connecting sheet 10 can be arranged on the connecting terminal 4, when the bus bar is connected with the other element, the connecting terminal 4 can be laser welded with the copper conductive terminal of the other element through the intermediate connecting sheet 10. The connecting sheet 10 as an intermediate layer can effectively isolate aluminum and copper to prevent them from directly contacting, thereby avoiding the occurrence of adverse reactions and avoiding the generation of copper-aluminum brittle oxides between the connecting terminal 4 and the other element in the welding process, thereby ensuring the welding quality. At the same time, the nickel sheet can withstand higher temperatures and remain stable in a high-temperature environment, so it can improve the corrosion resistance and heat resistance of the connection part. Since the connecting sheet 10 has good weldability with copper and aluminum, more welding methods can be selected.
[0035] A power electronic unit, such as Figure 2 As shown, the power electronic unit includes a filter 5 and a capacitor 6, and the bus bars in the filter 5 and the capacitor 6 are the bus bars described above. When the bus bar in the filter 5 is connected with the bus bar in the capacitor 6, it belongs to the connection between the same kind of copper-aluminum composite materials, and the connection by molten metal should be avoided to avoid the generation of brittle oxides between copper and aluminum, so tin soldering, ultrasonic welding, riveting and other non-melting connection methods can be used here to realize reliable connection of the two and ensure the connection strength and overcurrent capacity.
[0036] Further, the power electronic unit further includes a housing 7, the filter 5 and the capacitor 6 are arranged in the housing 7, and the filter 5 and the capacitor 6 are filled with potting glue between the filter 5 and the capacitor 6 and the housing 7. The potting glue can be epoxy resin, and other types of potting glue can also be selected by those skilled in the art as needed.
[0037] In this embodiment, the original split mounting method is cancelled, and the filter 5 and the capacitor 6 are integrally encapsulated in the housing 7, so that it is not necessary to add an independent envelope structure to the filter 5 and the capacitor 6, the space occupied by the filter 5 and the capacitor 6 in the housing 7 is reduced, the point positions for fixing the filter 5 and the capacitor 6 in the housing 7 need to be machined, the integration degree of the power electronic unit is improved, the machining and assembly difficulty is reduced, the process route is shortened, and the assembly efficiency is improved. After integrally encapsulating, the potting glue can fix the internal parts after curing and can play the effects of isolating water vapor, sealing and insulation.
[0038] Further, in order to improve the heat dissipation effect of the filter 5 and the capacitor 6, the shell 7 is made of metal in the embodiment, and the heat conduction performance of the metal is better than that of the plastic, so that the heat in the shell 1 is more easily dissipated. In addition, since the filter 5 and the capacitor 6 do not have a separate envelope structure, and the filter 5 and the capacitor 6 are integrally encapsulated in the shell 7, there is no envelope obstruction between the filter 5 and the capacitor 6 and the shell 7, the distance is closer, and the heat in the filter 5 and the capacitor 6 is more easily dissipated into the shell 7, further improving the heat dissipation effect of the filter 5 and the capacitor 6, improving the tolerance under extreme working conditions, and prolonging the service life.
[0039] As shown in Figure 2 In order to reduce the overall size of the power electronic unit and further improve the power density, the filter 5 and the capacitor 6 are arranged side by side in the shell 7 in the embodiment. The power electronic unit further comprises a power module 8 arranged above the filter 5 and the capacitor 6, and a printed circuit board assembly 9 arranged above the power module 8. The shell 7 serves as a total envelope, and the main internal components are arranged from bottom to top as follows: the filter 5 and the capacitor 6 arranged side by side, the power module 8, and the printed circuit board assembly 9, thereby forming an internal structure with high power density, compact structure, and small volume.
[0040] When the bus bar in the capacitor is connected with the power module 9, the terminal of the power module 9 is generally made of copper, and then the connecting piece can be welded on the aluminum terminal 4 in the bus bar of the capacitor as described above, and the copper terminal of the power module 9 is connected through the connecting piece.
[0041] Those skilled in the art will appreciate that the combination of features of different embodiments means that they are within the scope of the application and form different embodiments, even though some embodiments described herein include certain features but not others included in other embodiments. For example, in the claims of the application, any one of the claimed embodiments can be used in any combination.
[0042] So far, the technical scheme of the utility model has been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the utility model is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to related technical features without deviating from the principles of the utility model, and the technical schemes after the changes or replacements will fall within the protection scope of the utility model.
Claims
1. A copper-aluminum composite busbar, characterized by, Comprise: an aluminum layer (1) including an upper surface and a lower surface opposite to each other along a first direction; a first copper layer (2) disposed on the upper surface; a second copper layer (3) disposed on the lower surface; a connecting terminal (4) at a portion of the aluminum layer (1) protruding from the first copper layer (2) and the second copper layer (3) along a second direction; a connecting tab (10) disposed on an end of the connecting terminal (4) away from the first copper layer (2) along the second direction.
2. The copper-aluminum composite busbar according to claim 1, wherein: the thickness of the first copper layer (2) is the same as the thickness of the second copper layer (3).
3. The copper-aluminum composite busbar according to claim 1, wherein: the thickness of the aluminum layer (1) is greater than the thickness of the first copper layer (2); the thickness of the aluminum layer (1) is greater than the thickness of the second copper layer (3).
4. The copper-aluminum composite busbar according to claim 1, wherein: the aluminum layer (1), the first copper layer (2) and the second copper layer (3) are integrally formed.
5. A power electronic unit comprising a filter (5) and a capacitor (6), characterized in that, The busbar in the filter (5) and the capacitor (6) is the copper-aluminum composite busbar according to any one of claims 1-4.
6. The power electronic unit of claim 5, characterized in that The power electronic unit further comprises: an outer shell (7) in which the filter (5) and the capacitor (6) are disposed, and between the filter (5) and the capacitor (6) and the outer shell (7) is filled with potting glue.
7. The power electronic unit according to claim 6, wherein: the filter (5) and the capacitor (6) are disposed side by side in the outer shell (7).
8. The power electronic unit of claim 7, characterized in that The power electronic unit further comprises: a power module (8) disposed above the filter (5) and the capacitor (6); a printed circuit board assembly (9) disposed above the power module (8).
9. The power electronic unit according to claim 6, wherein: the outer shell (7) is a metal shell.