A high-pressure aluminum bar for new energy vehicles and its preparation method

Abstract

The present invention discloses a high-voltage aluminum busbar for new energy vehicles and a method for preparing the same. The high-voltage aluminum busbar comprises an aluminum alloy conductor, an oxide layer, and a shielding layer arranged from inside to outside. The oxide layer is a micro-arc oxidation layer, and the shielding layer is a PA12 composite material containing Ni metal. A silane coupling agent is provided between the oxide layer and the shielding layer. The high-voltage aluminum busbar for new energy vehicles of the present invention uses a micro-arc oxidation aluminum oxide layer, and a PA12 material with Ni metal composited on the outer surface of the oxide layer. Compared with conventional oxide layer structures, the high-voltage aluminum busbar has stronger corrosion resistance, wear resistance, and insulation properties. The Ni metal-doped PA12 composite material and the oxide layer have a tighter bond, making it less likely for the oxide layer and shielding layer to peel off during use, effectively extending the service life of the aluminum busbar and ensuring the stability of the high-voltage electrical system.

Description

Technical Field

[0001] The present invention relates to a high-pressure aluminum bar for new energy vehicles and a preparation method thereof, belonging to the technical field of new energy. Background Art

[0002] In new energy vehicles, aluminum is widely used in automotive components due to its lightweight, high strength, and excellent electrical conductivity. High-voltage aluminum busbars are key conductive components in the high-voltage electrical systems of new energy vehicles. They are primarily used for connecting power battery packs and as fast-charging interfaces for power transmission between motors and electronic control systems. These applications require a combination of high conductivity, lightweight, corrosion resistance, and reliability. Due to the high voltage, high humidity, high vibration, and highly corrosive operating environments, high corrosion resistance and corrosion resistance are crucial for the operation of high-voltage electrical systems in new energy vehicles. After forming an oxide layer on the aluminum surface, a shielding layer is typically applied. Currently, commercially available high-voltage aluminum busbars often suffer from poor adhesion between the oxide and shielding layers, flaking of the shielding layer after a period of use, and insufficient corrosion resistance. The tightness and corrosion resistance of the shielding layer significantly impact the lifespan and performance of aluminum busbars in new energy vehicles. Improving the adhesion between the oxide and shielding layers and extending the service life of aluminum busbars has become a key issue facing the industry. Summary of the Invention

[0003] In order to solve the problems in the above-mentioned background technology, the present invention provides a high-voltage aluminum busbar for new energy vehicles, including an aluminum alloy conductor, an oxide layer and a shielding layer arranged from the inside to the outside, wherein the oxide layer is a micro-arc oxidation layer, and the shielding layer is a PA12 composite material containing Ni metal.

[0004] The present invention discloses a high-voltage aluminum busbar for new energy vehicles. The busbar is constructed using a micro-arc oxidation process to form an aluminum oxide layer. The PA12 material is then composited with Ni metal on the outside of the oxide layer. Compared to conventional oxide layer structures, the busbar exhibits enhanced corrosion resistance, wear resistance, and insulation properties. The Ni metal-doped PA12 composite material and the oxide layer bond more tightly, making it less susceptible to peeling between the oxide layer and the shielding layer during use. This effectively extends the busbar's service life and ensures the stability of the high-voltage electrical system. The uniform thickness of the oxide layer formed by micro-arc oxidation effectively improves the busbar's corrosion resistance. The addition of Ni metal enhances the mechanical strength and thermal stability of the shielding layer, further ensuring the long-term, stable operation of the high-voltage busbar in complex environments.

[0005] Furthermore or alternatively, the PA12 composite material is doped with 5-10 wt% of a maleic anhydride graft copolymer and 10% of glass fiber. This composite material significantly enhances the material's mechanical properties and thermal conductivity, further improving the stability and durability of high-voltage aluminum busbars in extreme environments, and ensuring the long-term reliable operation of high-voltage electrical systems in new energy vehicles. The addition of glass fiber effectively improves the tensile strength, rigidity, and impact resistance of the PA12 composite material, maintaining its external structural integrity under mechanical vibration, impact, or long-term stress, preventing cracking or deformation and maintaining structural stability.

[0006] In addition, the present invention also provides a method for preparing a high-pressure aluminum busbar for new energy vehicles, comprising the following steps:

[0007] S1. Polish, degrease, neutralize and wash the aluminum busbar;

[0008] S2. Performing micro-arc oxidation on the aluminum busbar to form an oxide layer;

[0009] S3, washing the aluminum busbar after micro-arc oxidation, and then drying it;

[0010] S4. Cover the dried workpiece with a shielding layer.

[0011] This method uses a pre-treatment followed by micro-arc oxidation to form the oxide layer. Compared to traditional direct oxidation processes, the oxide layer bonds more firmly to the substrate, resulting in a smoother surface finish, effectively reducing the risk of corrosive media intrusion, and further improving the overall performance and service life of the aluminum busbar. The aluminum busbar's micro-arc oxidation layer produced using this method can achieve a breakdown voltage of up to 1000V / μm, far exceeding the 800V / μm required by high-voltage systems for new energy vehicles. The oxide layer can withstand salt spray corrosion for over 1000 hours, making it more adaptable to harsh environments such as humidity and salt spray.

[0012] Furthermore or optionally, the micro-arc oxidation process is carried out in an AC mode, the electrolysis temperature is controlled to be below 40°C during the micro-arc oxidation process, and the electrolyte is stirred during the micro-arc oxidation process. This treatment method uses an AC power supply and periodically changes the direction of the electric field to avoid the unipolar polarization effect in the DC mode, making the micro-arc discharge in various areas of the aluminum busbar surface more uniform, forming a dense and crack-free aluminum oxide layer, inhibiting the excessive dissolution of metal ions caused by unidirectional current, and avoiding the appearance of ablation pits or micropore defects on the surface. This process not only improves the uniformity and density of the oxide layer, but also significantly enhances the corrosion resistance and electrical insulation properties of the aluminum busbar, ensuring its long-term stable operation in a high-voltage environment.

[0013] Furthermore or alternatively, the thickness of the oxide layer of the aluminum busbar after micro-arc oxidation treatment is 0.01 μm to 1 mm, and the porosity is 5 to 10%. In actual operation, the oxide layer thickness can be adjusted according to the application, as long as it meets the requirements of the high-voltage system of new energy vehicles. In actual production, a medium-thick layer of 10 to 100 μm is generally used. When it is necessary to operate in high salt fog and high vibration areas, the thick oxide layer can provide protection. In specific operations, the oxide layer thickness can be increased to 100 μm to 1 mm. In actual operation, the thermal stress can also be adjusted by controlling the porosity of the coating. The smaller the coating porosity, the smaller the thermal stress between the oxide coating and the aluminum substrate, and the lower the possibility of coating cracking under high-temperature conditions due to inconsistent expansion coefficients.

[0014] Furthermore or optionally, the voltage range during the micro-arc oxidation process is 0-600V, and the frequency is greater than 1kHz. During the micro-arc oxidation process, it is necessary to adjust the voltage step by step. In the initial stage of establishing the basic oxide film, a low voltage state of less than 300V is adopted, and a medium voltage state of 300-450V is adopted in the arc starting stage to improve the hardness and density of the coating and balance its toughness and insulation. After the arc starting operation is completed, the voltage is maintained at above 450V to accelerate the migration and accumulation of the oxide layer. During the accumulation process, it is necessary to cool and stir the electrolyte. In actual operation, circulating cooling and mechanical stirring are more effective.

[0015] Furthermore, or optionally, the PA12 composite material has a thickness of 0.2-0.6mm. In practice, a smaller thickness is used to meet low-frequency shielding requirements (SE > 30dB), while an appropriate increase in thickness is used to meet high-frequency shielding requirements (SE > 50dB) to ensure effective electromagnetic shielding. By precisely controlling voltage and electrolyte parameters, optimized oxide layer performance can be achieved in different application scenarios, ensuring the aluminum busbar's mechanical strength while also improving its reliability and service life in complex environments.

[0016] Further or optionally, before performing the insulating coating step S4, the surface of the oxide layer is subjected to plasma activation treatment. This process can effectively remove trace amounts of grease, dust, or electrolyte decomposition products attached during the micro-arc oxidation process, and remove the weak hydroxyl bonding layer formed by absorbing water molecules in the air or forming on the surface of the oxide layer, thereby avoiding interface defects generated during the subsequent coating process. During the plasma activation treatment, the plasma active substance reacts with the surface of the oxide layer to generate a large number of oxygen-containing polar groups, which can greatly increase the surface energy of the oxide layer, effectively improve the wettability between PA12 and the oxide layer, form a stronger bonding interface, and enhance the mechanical interlocking strength between the oxide layer and PA12.

[0017] Further or optionally, after completing the plasma activation process, a silane coupling agent is sprayed on the surface of the oxide layer. One end of the silane coupling agent is a hydrolyzable alkoxy group, and the other end is an organic functional group. The hydrolyzed silane coupling agent can condense with the plasma-activated oxide layer to form a stable Si-O-Al covalent bond, and its organic functional group part can chemically react with the maleic anhydride grafted copolymer part in PA12 to form a stable chemical bond connection, thereby further improving the interface bonding strength between PA12 and the oxide layer, alleviating the difference in thermal expansion coefficient between the oxide layer and PA12, and effectively inhibiting interface cracking under thermal cycling.

[0018] Furthermore or optionally, in the plasma activation process, the activation gas source is O2, the input power is 80W, and the treatment time is 3 minutes. During the above treatment process, the O2 plasma dissociates into active oxygen ions through high-energy electron collisions, which react with the surface hydroxyl groups of the oxide layer to generate a high density of oxygen-containing polar groups, significantly improving the surface energy interaction activity between the oxide layer and PA12. Compared with other treatment processes, this process does not treat or destroy the main crystalline phase of the micro-arc oxidation layer. The -COOH groups introduced by it interact with the silane coupling agent through acid-base interaction, further improving the bonding strength of the silane film.

[0019] By adopting the above technical solution, the present invention has the following beneficial effects:

[0020] (1) The high-voltage aluminum busbar for new energy vehicles of the present invention adopts a micro-arc oxidation aluminum oxide layer, and the outer surface of the oxide layer adopts a PA12 material with a composite Ni metal. Compared with the ordinary oxide layer structure, its corrosion resistance, wear resistance and insulation are stronger. The bonding force between the Ni metal-doped PA12 composite material and the oxide layer is tighter, and the oxide layer and the shielding layer are less likely to peel off during use. This solution can effectively extend the service life of the aluminum busbar and ensure the stability of the high-voltage electrical system. The oxide layer formed by the micro-arc oxidation technology has a uniform thickness, which effectively improves the corrosion resistance of the aluminum busbar. At the same time, the addition of Ni metal enhances the mechanical strength and thermal stability of the shielding layer, further ensuring the long-term stable operation of the high-voltage aluminum busbar in complex environments.

[0021] (2) The PA12 composite material of the high-voltage aluminum busbar for new energy vehicles of the present invention is doped with 5-10 wt% of maleic anhydride graft copolymer and 10% of glass fiber, which significantly enhances the mechanical properties and thermal conductivity of the material, further improves the stability and durability of the high-voltage aluminum busbar in extreme environments, and ensures the long-term reliable operation of the high-voltage electrical system of new energy vehicles.

[0022] (3) The present invention also provides a method for preparing high-voltage aluminum busbars for new energy vehicles. The method forms an oxide layer by pre-treating the busbars followed by micro-arc oxidation. Compared with the traditional direct oxidation process, the oxide layer is more firmly bonded to the substrate and has a higher surface finish, effectively reducing the risk of corrosive media intrusion and further improving the overall performance and service life of the aluminum busbars. The aluminum oxide micro-arc oxidation layer prepared by this method can achieve a breakdown voltage of up to 1000V / μm for the aluminum busbars, far exceeding the 800V / μm required by the high-voltage system of new energy vehicles. The oxide layer can withstand salt spray corrosion for more than 1000 hours, making it more adaptable to harsh environments such as humidity and salt spray.

[0023] (4) The preparation method of a high-voltage aluminum busbar for new energy vehicles of the present invention adopts an AC mode for micro-arc oxidation treatment. During the treatment process, an AC power supply is used to periodically change the direction of the electric field, thereby avoiding the unipolar polarization effect in the DC mode. The micro-arc discharge in each area of ​​the aluminum busbar surface can be made more uniform, forming a dense and crack-free aluminum oxide layer, inhibiting the excessive dissolution of metal ions caused by unidirectional current, and avoiding the occurrence of ablation pits or micropore defects on the surface.

[0024] (5) The method for preparing a high-voltage aluminum busbar for new energy vehicles of the present invention controls the thickness and porosity of the oxide layer, and can adjust the thickness and porosity of the oxide layer according to the use environment of the product to meet the actual use environment requirements.

[0025] (6) The preparation method of a high-voltage aluminum busbar for new energy vehicles of the present invention adopts a step-by-step voltage adjustment scheme during the micro-arc oxidation treatment process, so that the ceramic coating can take into account both toughness and insulation during the generation process, avoiding the stress concentration of the coating caused by sudden voltage changes, ensuring the uniformity and density of the coating, further improving the durability and reliability of the aluminum busbar, and adapting to the stringent requirements of the high-voltage system of new energy vehicles.

[0026] (7) The method for preparing a high-voltage aluminum busbar for new energy vehicles of the present invention controls the thickness of the shielding layer during the preparation of the PA12 composite layer. The thickness of the shielding layer can be controlled according to the shielding requirements, and the shielding effect can be met with different requirements.

[0027] (8) The present invention relates to a method for preparing a high-voltage aluminum busbar for new energy vehicles. Before applying the shielding layer coating, the surface of the oxide layer is subjected to plasma activation treatment. The plasma active substances react with the surface of the oxide layer to generate a large number of oxygen-containing polar groups, which can significantly increase the surface energy of the oxide layer, effectively improve the wettability between PA12 and the oxide layer, form a stronger bonding interface, and enhance the mechanical interlocking strength between the oxide layer and PA12. By precisely controlling the voltage and electrolyte parameters, the optimized oxide layer performance can be achieved in different application scenarios, which not only ensures the mechanical strength of the aluminum busbar, but also improves its reliability and service life in complex environments.

[0028] (9) In the preparation method of a high-voltage aluminum busbar for new energy vehicles of the present invention, a silane coupling agent is sprayed on the surface of the oxide layer after completing the plasma activation process. The hydrolyzed silane coupling agent can form a stable Si-O-Al covalent bond with the oxide layer after plasma activation through condensation, further improving the interface bonding strength between PA12 and the oxide layer, alleviating the difference in thermal expansion coefficient between the oxide layer and PA12, and effectively inhibiting interface cracking under thermal cycling.

[0029] (10) The activation gas source of the ion activation process of the present invention is O2. The O2 plasma dissociates into active oxygen ions through high-energy electron collisions, which react with the surface hydroxyl groups of the oxide layer to generate high-density oxygen-containing polar groups, significantly improving the surface energy interaction activity between the oxide layer and PA12. This process does not treat or destroy the main crystal phase of the micro-arc oxidation layer. The -COOH groups introduced by it interact with the silane coupling agent to produce acid-base interactions, thereby further improving the bonding strength of the silane film. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0031] Figure 1 It is a structural schematic diagram of the present invention.

[0032] The reference numerals in the accompanying drawings are:

[0033] Aluminum alloy conductor 1, oxide layer 2, shielding layer 3. DETAILED DESCRIPTION

[0034] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0037] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0038] In the description of the embodiments of the present invention, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0039] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "setting", "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The present invention is further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are not intended to limit the scope of protection of the present invention.

[0040] See Figure 1 A high-voltage aluminum busbar for new energy vehicles comprises an aluminum alloy conductor 1, an oxide layer 2, and a shielding layer 3 arranged from the inside out. The oxide layer 2 is a micro-arc oxidation layer, and the shielding layer 3 is a PA12 composite material containing Ni metal.

[0041] Among the above materials, PA12 is doped with 5-10 wt% maleic anhydride graft copolymer and 10% glass fiber. After Ni doping is completed, a conductive network is formed inside PA12. When shielding performance is required for the aluminum busbar, electromagnetic shielding can be achieved inside the cable.

[0042] In order to prepare the above-mentioned high-pressure aluminum busbar for new energy vehicles and prevent the PA12 from peeling off from the aluminum busbar after long-term use, the present invention also provides a method for preparing the above-mentioned high-pressure aluminum busbar for new energy vehicles, which specifically includes the following steps:

[0043] S1. Polish, degrease, neutralize and wash the aluminum busbar;

[0044] S2. Performing micro-arc oxidation on the aluminum busbar to form an oxide layer;

[0045] S3, washing the aluminum busbar after micro-arc oxidation, and then drying it;

[0046] S4. Cover the dried workpiece with a shielding layer.

[0047] During the micro-arc oxidation process, it is necessary to strictly control the current size and voltage intensity. A large amount of heat will be released during the micro-arc oxidation process. Due to the high resistivity of the electrolyte in the gaps of the oxide film and in the barrier layer, the electrolyte rises too quickly during the micro-plasma discharge process, which will accelerate the dissolution of the oxide film. The dissolution rate of the oxide film is greater than the film formation rate, which will cause corrosion on the surface of the metal substrate. In order to ensure the quality of the oxide film, the temperature of the electrolyte needs to be controlled. In actual operation, a circulating cooling system can be used to control its temperature below 40°C. Specifically, the circulating cooling system generally includes a cooling compressor, a heat exchanger, and an acid and alkali resistant submersible pump.

[0048] During micro-arc oxidation, it is necessary to enhance the mass transfer effect, strengthen the flow of the electrolyte, and improve the adsorption capacity of anions on the aluminum anode. In actual operation, mechanical devices are generally used to stir the electrolyte to increase the convection circulation speed of the electrolyte.

[0049] During operation, the voltage range of the micro-arc oxidation treatment is controlled to be 0-600V, the frequency is greater than 1kHz, and the oxidation process adopts three-stage treatment of less than 300V, 300-450V, and greater than 450V. It should be noted that after the arcing process is completed, the oxidation treatment above 450V should be carried out to ensure the toughness and insulation of the coating.

[0050] During the ceramicization process, the thickness of the oxide layer needs to be controlled according to the use requirements. Specifically, the micro-arc oxidation operation time and voltage need to be controlled so that the oxide layer thickness is controlled at 0.01um-1mm and the porosity is controlled at 5~10%.

[0051] Before applying the shielding layer, the oxide layer needs to be plasma activated. The activation source is O2, with an input power of 80W and a treatment time of 3 minutes. After the ion activation process, a silane coupling agent is sprayed on the surface. Then, PA12 is coated on the ceramicized aluminum busbar surface. The thickness of the PA12 material is controlled to be 0.2-0.6mm.

[0052] Four groups of samples were prepared using the above method, and the test results are shown in Table 1:

[0053] Table 1 Test results at different metal oxide layer thicknesses

[0054]

[0055] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-pressure aluminum busbar for new energy vehicles, characterized by: The invention comprises an aluminum alloy conductor (1), an oxide layer (2), and a shielding layer (3) arranged from the inside out, wherein the oxide layer (2) is a micro-arc oxide layer, and the shielding layer (3) is a PA12 composite material containing Ni metal; a silane coupling agent is provided between the oxide layer (2) and the shielding layer (3).

2. The high-voltage aluminum busbar for new energy vehicles according to claim 1, characterized in that: The PA12 composite material is doped with 5-10 wt% of a maleic anhydride graft copolymer and 10% of glass fiber.

3. The method for preparing a high-pressure aluminum busbar for new energy vehicles according to claim 1, characterized in that The following steps are involved: S1. Polish, degrease, neutralize and wash the aluminum busbar; S2, performing micro-arc oxidation treatment on the aluminum busbar treated in S1 to form an oxide layer (2); S3, washing the aluminum busbar after micro-arc oxidation, and then drying it; S4, covering the dried workpiece with a shielding layer (3).

4. The method for preparing a high-pressure aluminum busbar for new energy vehicles according to claim 3, characterized in that: The micro-arc oxidation treatment process adopts an AC mode for treatment, the electrolysis temperature is controlled to be below 40° C. during the micro-arc oxidation treatment process, and the electrolyte is stirred during the micro-arc oxidation process.

5. The method for preparing a high-pressure aluminum busbar for new energy vehicles according to claim 3, characterized in that: The thickness of the oxide layer (2) of the aluminum busbar after micro-arc oxidation treatment is 0.01um-1mm, and the porosity is 5-10%.

6. The method for preparing a high-pressure aluminum busbar for new energy vehicles according to claim 3, characterized in that: The voltage range during the micro-arc oxidation treatment is 0-600V, and the frequency is greater than 1 kHz.

7. The method for preparing a high-pressure aluminum busbar for new energy vehicles according to claim 3, characterized in that: The PA12 composite material of the shielding layer (3) has a thickness of 0.2-0.6 mm.

8. The method for preparing a high-pressure aluminum busbar for new energy vehicles according to claim 3, characterized in that: Before performing the shielding layer (3) coating step S4, the surface of the oxide layer (2) is subjected to plasma activation treatment.

9. The method for preparing a high-pressure aluminum busbar for new energy vehicles according to claim 8, characterized in that: After completing the plasma activation process, a silane coupling agent is sprayed on the surface of the oxide layer (2).

10. The method for preparing a high-pressure aluminum busbar for new energy vehicles according to claim 8, characterized in that: In the plasma activation process, the activation gas source is O2, the input power is 80W, and the processing time is 3 minutes.

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