An insulating aluminum busbar for high-voltage connection in a power battery system, its preparation method and its application

Abstract

This invention relates to the field of insulating aluminum busbar technology, and in particular to an insulating aluminum busbar for high-voltage connection in a power battery system, its preparation method, and its application. An insulating aluminum busbar for high-voltage connection in a power battery system includes: a three-dimensionally bent aluminum alloy substrate; a ceramic insulating layer, which covers the outer surface of the three-dimensionally bent aluminum alloy substrate and is metallurgically bonded to it; and two conductive ends, which are located at both ends of the three-dimensionally bent aluminum alloy substrate, with a nickel sheet fixedly connected to each conductive end and covered with a heat-shrink tubing. This application achieves metallurgical bonding between the ceramic insulating layer and the aluminum substrate, resulting in extremely strong bonding and solving the problem of coating peeling. The two conductive ends located at both ends of the substrate ensure the conductivity of the high-voltage connection and provide secondary protection for the welded area through the heat-shrink tubing, improving connection reliability.

Description

Technical Field

[0001] This invention relates to the field of insulating aluminum busbar technology, and in particular to an insulating aluminum busbar for high-voltage connection in power battery systems, its preparation method, and its application. Background Technology

[0002] As new energy vehicles rapidly evolve towards high-voltage platforms, higher demands are being placed on the electrical performance, reliability, and lightweighting of connecting components and high-voltage cables within battery systems. Currently, the industry commonly uses extruded polymer materials to insulate aluminum alloy busbars. This traditional process has the following main drawbacks:

[0003] 1) Poor adhesion and heat resistance: The polymer coating and the metal substrate are physically attached, and the adhesion is weak. Under long-term thermal cycling or high-temperature environment, it is prone to aging, cracking and peeling, resulting in insulation failure.

[0004] 2) Complex process and difficult yield control: The extrusion process requires precise control of temperature, pressure, and speed, which can easily lead to uneven wall thickness and surface defects (such as pores and impurities), requiring strict subsequent testing. In order to make the end connection, the insulation layer also needs to be mechanically or laser peeled off, which is a complicated process and may damage the substrate.

[0005] 3) Environmental protection and recycling issues: The use of polymer materials increases the difficulty of separation and recycling after the product life cycle, which does not meet the requirements of green manufacturing and circular economy.

[0006] 4) Insufficient overall performance: Traditional insulation layers have limited wear resistance and chemical corrosion resistance (especially electrolyte), which poses a challenge to long-term reliability in harsh battery pack environments.

[0007] To overcome these problems, the industry has begun exploring technologies for in-situ generation of ceramic insulating layers on aluminum surfaces, such as anodizing. However, conventional anodized films are thin, have low hardness, and generally poor wear and corrosion resistance, and their bonding strength with the substrate still needs improvement. This makes it difficult to meet the stringent requirements for insulation, mechanical reliability, and long-term durability under the high-voltage, high-current conditions of power batteries. Designing a novel ceramic insulation process suitable for complex-shaped aluminum busbars, and achieving an optimal balance between performance, cost, and environmental protection, has become a pressing technical challenge in this field. Summary of the Invention

[0008] To overcome the aforementioned deficiencies, this application provides an insulating aluminum busbar for high-voltage connection in a power battery system, its preparation method, and its application.

[0009] In a first aspect, this application provides an insulating aluminum busbar for high-voltage connection in a power battery system, employing the following technical solution: An insulating aluminum busbar for high-voltage connection in a power battery system, comprising: Aluminum alloy substrate formed by three-dimensional bending; A ceramic insulating layer, which covers the outer surface of the three-dimensionally bent aluminum alloy substrate and is metallurgically bonded to the three-dimensionally bent aluminum alloy substrate; Two conductive ends are provided at both ends of the three-dimensionally bent aluminum alloy substrate, and each conductive end is fixedly connected with a nickel sheet and covered with a heat shrink tubing.

[0010] Through the above technical solution, this application clarifies that it consists of three core components: a three-dimensionally bent aluminum alloy substrate, a ceramic insulating layer, and two conductive terminals. The three-dimensionally bent substrate adapts to the complex spatial layout within the power battery pack, solving the problem of poor compatibility with traditional straight aluminum busbars; the ceramic insulating layer achieves a metallurgical bond with the aluminum substrate, resulting in extremely strong adhesion and completely solving the coating peeling problem; the two conductive terminals are located at both ends of the substrate, each with a fixed nickel sheet and covered with heat-shrink tubing, ensuring the conductivity of the high-voltage connection and providing secondary protection for the welded area through the heat-shrink tubing, thus improving connection reliability.

[0011] Furthermore, the thickness of the ceramic insulating layer is 20-100 μm, the breakdown voltage of the ceramic insulating layer at power frequency is not less than 3600V, and the volume resistivity of the ceramic insulating layer is >1×10⁻⁶. 13 Ω·cm.

[0012] Through the above technical solution, this application further defines the key performance parameters of the ceramic insulation layer, accurately adapting to the insulation requirements of the high-voltage platform of new energy vehicles. The thickness range can be flexibly adjusted according to the actual withstand voltage design, while the breakdown voltage and volume resistivity parameters ensure the insulation reliability of the aluminum busbar in the high-voltage working environment, avoiding safety hazards such as short circuits and leakage caused by insufficient insulation performance.

[0013] Secondly, this application provides a method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system, characterized by comprising the following steps: S1. Continuously extrude 6101 aluminum alloy billet to obtain aluminum busbar substrate, and perform aging treatment on the aluminum busbar substrate; S2. The aged aluminum busbar substrate is 3D bent into shape to obtain an aluminum busbar workpiece with a preset three-dimensional shape; S3. Perform a peelable sealing treatment on the conductive part at the end of the aluminum busbar workpiece, and then perform surface cleaning and activation pretreatment on the sealed aluminum busbar workpiece. S4. The pretreated aluminum busbar workpiece is used as the anode and placed in the electrolyte. An electrochemical oxidation process is used to grow a continuous ceramic insulating layer on its surface in situ. S5. After cleaning and optional post-treatment of the oxidized workpiece, remove the end seals, weld nickel sheets onto the exposed aluminum substrate and punch holes, and fit heat shrink tubing on the welded parts to prepare an insulating aluminum busbar for high-voltage connection of power battery system.

[0014] Through the above technical solutions, this application defines the core preparation process of the insulating aluminum busbar. Step S1 integrates continuous extrusion and aging treatment, which not only ensures the dimensional accuracy and density of the aluminum busbar substrate, but also improves its mechanical strength. 3D bending and forming adapts to the three-dimensional structural requirements of the product. Furthermore, by integrating the sealing treatment with the pretreatment, the process flow is simplified. At the same time, sealing protects the conductive parts at the ends, preventing subsequent oxidation processes from affecting the conductivity. In addition, this application also uses an electrochemical oxidation process to generate a ceramic insulating layer in situ, clarifying the core of the insulating layer preparation, covering two major branches: micro-arc oxidation and hard anodizing. Finally, this application integrates post-treatment, end processing and protection processes, simplifying the original process steps and clarifying the synergistic effect of each process.

[0015] Furthermore, the electrochemical oxidation process includes a micro-arc oxidation process, and the parameters in the micro-arc oxidation process satisfy the following formula (1): Ceramic layer thickness H MAO (μm)≈K1×U×√t (1); Where U is the final stable voltage (V), t is the oxidation time (min), and K1 is the process coefficient, the value of which ranges from 0.15 to 0.25 (μm·min). -1 / 2 ·V -1 ); and the breakdown voltage V of the ceramic insulating layer BD( V) and thickness H MAO The relationship satisfies the following formula (2): V BD ≈(40~50)×H MAO Equation (2).

[0016] Through the above technical solutions, this application specifies the electrochemical oxidation process as a micro-arc oxidation process. Formula (1) defines the relationship between the ceramic layer thickness and the final stable voltage, oxidation time, and process coefficient, and clarifies that the range of K1 values ​​can be derived from the target film thickness to improve process controllability. Formula (2) clarifies the relationship between breakdown voltage and film thickness, ensuring that the insulation performance matches the film thickness, and providing a theoretical basis for product withstand voltage design. This clause refines the implementation details of the micro-arc oxidation process through parameter quantification and formula limitation, which is different from the fuzzy parameter control of the traditional micro-arc oxidation process, and improves the repeatability and stability of the process.

[0017] Furthermore, the electrolyte in the micro-arc oxidation process is a silicate electrolyte or an aluminate electrolyte, and the operating voltage of the micro-arc oxidation process is 400-600V, and the current density is 5-15 A / dm³. 2 The processing time is 20-60 min, and the thickness of the resulting ceramic layer is 20-60 μm.

[0018] Through the above technical solution, this application further refines the specific implementation parameters of the micro-arc oxidation process, and clarifies that the electrolyte type is either silicate electrolyte or aluminate electrolyte, which ensures both the density of the ceramic layer and the metallurgical bonding effect, while also taking into account process efficiency and cost. The limitation of the electrolyte type is adapted to different performance requirements, with the silicate system focusing on bonding strength and the aluminate system focusing on corrosion resistance.

[0019] Furthermore, the electrochemical oxidation process includes a hard anodizing process, and the parameters of the hard anodizing process satisfy the following formula (3): Ceramic layer thickness HHAO (μm)≈K2×J×t (3); Where J is the current density (A / dm2), t is the oxidation time (min), and K2 is the film formation rate coefficient, with the value of K2 ranging from 0.3 to 0.4 (μm·dm2·A-1·min-1).

[0020] Through the above technical solutions, this application defines the electrochemical oxidation process as a hard anodizing process and clarifies the quantitative formula (3) of its core parameters, defining the relationship between ceramic layer thickness and current density, oxidation time, and film formation rate coefficient. Unlike the voltage-dominated film formation of micro-arc oxidation, hard anodizing is a current density-dominated film formation. The formula ensures that the film thickness is controllable. This clause improves the protection branch of the electrochemical oxidation process by clarifying the relationship of the core parameters of the hard anodizing process, covering the two mainstream in-situ ceramicization processes.

[0021] Furthermore, the electrolyte in the hard anodizing process includes a low-temperature sulfuric acid electrolyte or a mixed acid electrolyte, and the temperature in the hard anodizing process is maintained at -20~15℃, with a current density of 2-4 A / dm³. 2 The processing time is 30-90 min, and the thickness of the resulting oxide film is 20-50 μm.

[0022] Through the above technical solution, this application further refines the specific implementation parameters of the hard anodizing process, specifying that the electrolyte type is low-temperature sulfuric acid electrolyte or mixed acid electrolyte, limiting the process temperature to -20~15℃, current density to 2-4 A / dm², processing time to 30-90 min, and the final oxide film thickness to 20-50 μm. The limitation of the low-temperature environment can inhibit the chemical dissolution of the oxide film and ensure the film density; the limitation of the electrolyte type and current density adapts to the film formation requirements of hard anodizing, balancing film thickness and hardness.

[0023] Furthermore, the peelable sealing treatment in step S3 includes using peelable insulating adhesive or a special elastic sealing sleeve that is resistant to electrolyte corrosion, plasma arc breakdown, and high temperatures above 150°C.

[0024] Through the above technical solution, this application refines the specific implementation method of the peelable sealing treatment in step S3, specifying the use of peelable insulating adhesive or special elastic sealing sleeve that is resistant to electrolyte corrosion, plasma arc breakdown, and high temperatures above 150°C. Considering the characteristics of the micro-arc oxidation process, this avoids the problem of ordinary sealing materials being easily damaged or failing under high-voltage discharge, high temperature, and strong electrolyte environments, ensuring that the sealing area is not oxidized. Simultaneously, the peelable characteristic facilitates subsequent end processing without damaging the aluminum substrate.

[0025] Thirdly, this application discloses an application of an insulating aluminum busbar: An insulated aluminum busbar for high-voltage connection in a power battery system is used in the busbar connection within a power battery pack for new energy vehicles or as a conductor component for high-voltage fast charging cables.

[0026] Through the above technical solution, this application clarifies the specific application scenarios of the insulated aluminum busbar, namely, the busbar connection in the power battery PACK of new energy vehicles or as a conductor component of high-voltage fast charging cables.

[0027] In summary, this application has the following beneficial effects: First, this invention uses micro-arc oxidation or hard anodizing processes to grow a ceramic insulating layer in situ on the surface of an aluminum alloy substrate. This insulating layer forms a strong metallurgical bond with the aluminum substrate, eliminating the physical interface between the traditional polymer coating and the substrate. This extremely strong bonding completely solves the industry pain point of coating peeling and cracking caused by thermal cycling and mechanical vibration during long-term use of existing insulated aluminum bars, leading to insulation failure. Compared to traditional polymer insulating materials, the ceramic insulating layer of this invention has significantly improved heat resistance, allowing it to operate stably in high-temperature environments below 180°C for extended periods in power battery packs, and can withstand short-term localized thermal shocks above 250°C without performance degradation. The microhardness of the ceramic layer surface far exceeds that of polymer coatings, effectively resisting mechanical scratches and impacts during installation and use, preventing insulation damage. Simultaneously, the dense ceramic structure effectively blocks corrosive media such as salt spray and electrolyte, making it suitable for the harsh working environment of power battery packs, which is humid and may have micro-leakage of electrolyte.

[0028] Secondly, compared with the complex process of "extrusion molding-bending-extrusion coating-end peeling" commonly used in the prior art, this application eliminates the strict control of wall thickness accuracy and surface defects in the extrusion process, avoids quality hazards such as air holes, uneven wall thickness, and impurity residue that are prone to occur in the extrusion process, and eliminates the subsequent mechanical or laser peeling process of the end insulation layer, which greatly shortens the production process and reduces equipment investment and energy consumption.

[0029] Third, the ceramic insulating layer of this invention possesses excellent electrical insulation properties and a high volume resistivity. Compared to traditional polymer insulating materials, this invention precisely designs the ceramic layer thickness using a quantitative formula, achieving controllable adjustment of the withstand voltage level. Process parameters can be specifically adjusted according to the insulation requirements of different power battery systems, ensuring a high degree of match between the product's insulation performance and design needs. Furthermore, inorganic ceramic materials inherently possess excellent chemical stability, avoiding the aging, yellowing, embrittlement, corona corrosion, and electrolyte swelling problems that easily occur with polymer materials over long-term use. This results in superior long-term electrical stability, ensuring stable insulation performance of the insulating aluminum busbar throughout the entire lifespan of the power battery. This effectively avoids safety hazards such as short circuits and leakage caused by insulation aging, significantly improving the operational reliability and safety of the power battery system. Attached Figure Description

[0030] Figure 1 This is a partial structural schematic diagram of an insulating aluminum busbar for high-voltage connection in a power battery system according to the present invention; Figure 2 This is a process flow diagram of a method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system according to this application; The components include: 1. A three-dimensional bent aluminum alloy substrate; 2. A ceramic insulating layer; 3. A conductive end; 4. A nickel sheet; and 5. A heat shrink tubing. Detailed Implementation

[0031] The present application will be further described in detail below with reference to the embodiments.

[0032] The raw materials and instruments used in this embodiment are shown below, but are not limited thereto. Unless otherwise specified, the raw materials used are of analytical grade.

[0033] Example 1 A method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system includes the following preparation steps: S1. 6101 aluminum alloy billet is continuously extruded to obtain aluminum busbar substrate with a cross-sectional size of 30mm×5mm, and then the aluminum busbar substrate is subjected to aging treatment at 175℃×8h.

[0034] S2. After the aging treatment is completed, the aluminum busbar substrate is 3D bent and formed by CNC bending machine to obtain a preset three-dimensional shape aluminum busbar workpiece that matches the layout of the battery module. S3. For the conductive parts at both ends of the aluminum busbar workpiece, a 20mm length is applied using peelable silicone rubber putty resistant to 200℃ for peelable sealing, ensuring clear sealing boundaries and a tight seal. After sealing, the aluminum busbar workpiece undergoes surface cleaning and activation pretreatment in sequence. Mechanical pretreatment involves sandblasting to form a uniform matte surface; chemical degreasing uses an alkaline degreasing agent and is treated at 60℃ for 10 minutes until the workpiece surface is completely hydrophilic and forms a continuous water film; alkaline etching uses a 45g / L sodium hydroxide solution and is treated at 60℃ for 3 minutes; brightening uses a 30% (v / v) nitric acid solution for 1 minute; after each chemical treatment, a three-stage countercurrent water rinse is performed, and finally, the workpiece is rinsed with deionized water and dried in an 80℃ oven.

[0035] S4. After pretreatment, the aluminum busbar workpiece is used as the anode and firmly connected using a titanium alloy fixture to ensure good conductivity and that the contact point is located on a non-critical surface. The workpiece and the stainless steel cathode are immersed together in a silicate electrolyte and connected to a high-voltage bidirectional pulse power supply for micro-arc oxidation. Micro-arc oxidation adopts a constant current and constant voltage mode, with an initial current density of 10A / dm², the voltage gradually rising to a stable value of 500V, a pulse frequency of 500Hz, and the electrolyte maintained at 28℃ by a cooling system. The treatment time is 40 minutes, resulting in the in-situ growth of a continuous ceramic insulating layer on the workpiece surface.

[0036] S5. After micro-arc oxidation, rinse the workpiece surface with running tap water to remove residual electrolyte, and then clean it with deionized water. Next, immerse it in 90℃ hot water for 15 minutes for sealing. After sealing, dry it in an 85℃ oven. After drying, physically peel off the end-sealing putty, ultrasonically clean the exposed aluminum substrate end for 5 minutes, then ultrasonically weld a 0.2mm thick nickel sheet onto it, punching a Φ6mm connecting hole at the corresponding position. Finally, apply a heat-shrink tubing with adhesive to the nickel sheet welding area, heat to 120℃ to shrink and adhere the tubing, completing the preparation of the insulating aluminum busbar.

[0037] Example 2 A method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system includes the following preparation steps: S1. 6101 aluminum alloy billet is continuously extruded to obtain aluminum busbar substrate, and then the aluminum busbar substrate is subjected to aging treatment at 175℃×8h. S2. After the aging treatment is completed, a CNC bending machine is used for 3D bending to form a non-circular aluminum strip workpiece with a preset three-dimensional shape.

[0038] S3. Customized fluororubber elastic sealing sleeves are used to peel off the conductive parts at the ends of the aluminum busbar workpieces to ensure a tight and seamless seal. After sealing, the aluminum busbar workpieces undergo surface cleaning and activation pretreatment in sequence. Mechanical pretreatment involves polishing to obtain a smooth base. Chemical degreasing is performed using a neutral degreasing agent at 55℃ for 12 minutes until the workpiece surface is completely hydrophilic and forms a continuous water film. Alkali etching is performed using a 50g / L sodium hydroxide solution at 65℃ for 2 minutes. Brightening is performed using a mixed acid treatment of nitric acid and hydrofluoric acid for 0.8 minutes. After each chemical treatment, a three-stage countercurrent water rinse is performed, and finally, the workpiece is rinsed with deionized water and dried in an 80℃ oven.

[0039] S4. After pretreatment, the aluminum busbar workpiece is used as the anode and securely connected using an aluminum-titanium composite bracket to ensure good conductivity. The workpiece and the lead cathode are immersed together in a low-temperature sulfuric acid electrolyte. The electrolyte uses an optimized formula with sulfuric acid concentration of 190 g / L, oxalic acid concentration of 15 g / L, glycerol concentration of 22 mL / L, and cerium nitrate concentration of 2 g / L. The electrolyte temperature is maintained at 5 ± 2℃ by forced cooling using a refrigeration unit. Hard anodizing is performed using a constant current mode, with the current density controlled at 3 A / dm² and the oxidation time at 60 min. During the process, the voltage is gradually increased to 90 V to ensure uniform film growth.

[0040] S5. After hard anodizing, rinse the workpiece surface with cold water to remove residual electrolyte. Then, immerse it in 80°C hot water containing a sealant for 20 minutes to seal the holes. After that, dry it in an 85°C oven. After drying, remove the end sealing sleeve, ultrasonically clean the exposed aluminum substrate end for 5 minutes, then apply a 0.2mm thick nickel sheet by laser welding, and punch connection holes of the corresponding specifications. Finally, apply adhesive heat shrink tubing to the welding area, heat it to 125°C to shrink and adhere the heat shrink tubing, and complete the preparation of the insulating aluminum busbar.

[0041] It should be noted that the exposed aluminum substrate ends can also be nickel-plated in this application's technical solution.

[0042] Comparative Example 1 A method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system includes the following preparation steps: S1. 6101 aluminum alloy billet is continuously extruded to obtain aluminum busbar substrate, and then the aluminum busbar substrate is subjected to aging treatment at 175℃×8h. S2. After the aging treatment is completed, a CNC bending machine is used for 3D bending to form a non-circular aluminum strip workpiece with a preset three-dimensional shape.

[0043] S3. After bending, use an extruder to coat the surface with a 0.5mm thick PA12 insulation layer. Then use a laser cutter to precisely peel off the outer layer at the end to expose the aluminum substrate, followed by welding and other subsequent processes.

[0044] S4. Ultrasonic cleaning of the exposed aluminum substrate end for 5 minutes, followed by laser welding to attach a 0.2mm thick nickel sheet, and punching corresponding connection holes. Finally, heat shrink tubing with adhesive is fitted onto the welding area, and heated to 125℃ to shrink and adhere the heat shrink tubing, thus completing the preparation of the insulating aluminum busbar.

[0045] Comparative Example 2 A method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system includes the following preparation steps: S1. 6101 aluminum alloy billet is continuously extruded to obtain aluminum busbar substrate, and then the aluminum busbar substrate is subjected to aging treatment at 175℃×8h. S2. After the aging treatment is completed, a CNC bending machine is used for 3D bending to form a non-circular aluminum strip workpiece with a preset three-dimensional shape.

[0046] S3. Ultrasonic cleaning of the exposed aluminum substrate end for 5 minutes, followed by laser welding to attach a 0.2mm thick nickel sheet, and punching corresponding connection holes. Finally, heat shrink tubing with adhesive is fitted onto the welding area, and heated to 125℃ to shrink and adhere the heat shrink tubing, thus completing the preparation of the insulating aluminum busbar.

[0047] Performance testing Volume resistivity test: The test shall be conducted in accordance with GB / T1410-2006 "Test methods for volume resistivity and surface resistivity of solid insulating materials"; Breakdown voltage test: The test shall be conducted in accordance with GB / T1408.1-2021 "Electrical strength test methods for insulating materials - Part 1: Tests at power frequency"; Thermal conductivity test: The test was conducted in accordance with GB / T10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials - Protective Hot Plate Method". Long-term operating temperature test: The test shall be conducted in accordance with GB / T2423.2-2008 "Environmental testing - Part 2: Test methods - Test B: High temperature"; Microhardness test: The test shall be conducted in accordance with GB / T 4340.1-2009 "Metallic materials - Vickers hardness test - Part 1: Test method"; Taber abrasion test: The Taber abrasion tester was used to test the abrasion test according to the requirements of GB / T 17748-2016 "Aluminum and Aluminum Alloy Corrugated Plates". The test was conducted in accordance with GB / T 10125-2021 "Artificial Atmosphere Corrosion Test - Salt Spray Test", using a neutral salt spray test chamber. The specific test results are shown in Table 1 below. Table 1 Performance Test Table

[0048] As can be seen from the table above, combined with Examples 1-2 and Comparative Examples 1-2, the ceramic insulating layer of the present invention exhibits excellent electrical insulation performance and high volume resistivity. Compared to traditional polymer insulating materials, the present invention precisely designs the ceramic layer thickness using a quantitative formula, achieving controllable adjustment of the withstand voltage level. Process parameters can be specifically adjusted according to the insulation requirements of different power battery systems, ensuring a high degree of match between the product's insulation performance and design needs. Furthermore, inorganic ceramic materials possess excellent chemical stability, avoiding the aging, yellowing, embrittlement, corona corrosion, and electrolyte swelling problems that easily occur with polymer materials during long-term use. This results in superior long-term electrical stability, ensuring stable insulation performance of the insulating aluminum busbar throughout the entire lifespan of the power battery. This effectively avoids safety hazards such as short circuits and leakage caused by insulation aging, significantly improving the operational reliability and safety of the power battery system.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An insulating aluminum busbar for high-voltage connection in a power battery system, characterized in that, include: Aluminum alloy substrate formed by three-dimensional bending (1); A ceramic insulating layer (2) is wrapped around the outer surface of the three-dimensional bent aluminum alloy substrate (1) and is metallurgically bonded to the three-dimensional bent aluminum alloy substrate (1). Two conductive ends (3) are provided at both ends of the three-dimensional bent aluminum alloy substrate (1), and each conductive end (3) is fixedly connected with a nickel sheet (4) and covered with a heat shrink tube (5).

2. An insulating aluminum busbar for high-voltage connection of a power battery system according to claim 1, characterized in that, The thickness of the ceramic insulating layer (2) is 20-100 μm, the breakdown voltage of the ceramic insulating layer (2) at power frequency is not less than 3600V, and the volume resistivity of the ceramic insulating layer (2) is >1×10⁻⁶. 13 Ω·cm.

3. A method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system according to claim 1 or 2, characterized in that... Includes the following steps: S1. Continuously extruding aluminum alloy billets to obtain aluminum busbar substrates; S2. Perform 3D bending and forming on the aluminum busbar substrate to obtain an aluminum busbar workpiece with a preset three-dimensional shape; S3. Perform a peelable sealing treatment on the conductive part at the end of the aluminum busbar workpiece, and then perform surface cleaning and activation pretreatment on the sealed aluminum busbar workpiece. S4. The pretreated aluminum busbar workpiece is used as the anode and placed in the electrolyte. An electrochemical oxidation process is used to grow a continuous ceramic insulating layer on its surface in situ. S5. After cleaning and optional post-treatment of the oxidized workpiece, remove the end seals, weld nickel sheets onto the exposed aluminum substrate and punch holes, and fit heat shrink tubing on the welded parts to prepare an insulating aluminum busbar for high-voltage connection of power battery system.

4. The method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system according to claim 3, characterized in that, When the aluminum alloy billet is a 6-series aluminum alloy, the process also includes aging treatment of the aluminum busbar substrate.

5. The method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system according to claim 3, characterized in that, The electrochemical oxidation process includes a micro-arc oxidation process, and the parameters in the micro-arc oxidation process satisfy the following formula (1): Ceramic layer thickness H MAO (μm)≈K1×U×√t (1); Where U is the final stable voltage (V), t is the oxidation time (min), and K1 is the process coefficient, the value of which ranges from 0.15 to 0.25 (μm·min). -1 / 2 ·V -1 ); and the breakdown voltage V of the ceramic insulating layer BD( V) and thickness H MAO The relationship satisfies the following formula (2): V BD ≈(40~50)×H MAO Equation (2).

6. The method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system according to claim 5, characterized in that, The electrolyte used in the micro-arc oxidation process is a silicate electrolyte or an aluminate electrolyte. The operating voltage of the micro-arc oxidation process is 400-600V, and the current density is 5-15 A / dm³. 2 The processing time is 20-60 min, and the thickness of the resulting ceramic layer is 20-60 μm.

7. The method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system according to claim 3, characterized in that, The electrochemical oxidation process includes a hard anodizing process, and the parameters of the hard anodizing process satisfy the following formula (3): Ceramic layer thickness H HAO (μm)≈K2×J×t (3); Where J is the current density (A / dm³) 2 ), t is the oxidation time (min), and K2 is the film formation rate coefficient, wherein the value of K2 ranges from 0.3 to 0.4 (μm·dm). 2 ·A -1 ·min -1 ).

8. The method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system according to claim 5, characterized in that, The electrolyte in the hard anodizing process includes a low-temperature sulfuric acid electrolyte or a mixed acid electrolyte. The temperature in the hard anodizing process is maintained at -20~15℃, and the current density is 2-4 A / dm³. 2 The processing time is 30-90 min, and the thickness of the resulting oxide film is 20-50 μm.

9. The method for preparing an insulating aluminum busbar for high-voltage connection in a power battery system according to claim 4, characterized in that, Step S3 describes a peelable sealing process that involves using peelable insulating adhesive or a special elastic sealing sleeve that is resistant to electrolyte corrosion, plasma arc breakdown, and temperatures above 150°C.

10. An insulating aluminum busbar for high-voltage connection of a power battery system according to claim 1 or 2, characterized in that, The insulating aluminum busbar used for high-voltage connection of power battery system is applied to the busbar connection in the power battery PACK of new energy vehicle or as a conductor component of high-voltage fast charging cable.

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