Aluminum alloy profile, manufacturing method, battery pack box body, battery pack and electrical device

Abstract

The present application relates to an aluminum alloy profile, a manufacturing method, a battery pack box body, a battery pack and an electric device. By mass percentage, the aluminum alloy profile comprises the following components: 0.6-1.3% Si, 0.6-1.0% Mg, 0.6-0.73% Fe, 0.05-0.2% Cu, 0.1-0.2% Mn and 0.14-0.30% Sc, with the balance being Al and impurities, wherein the mass of a single impurity ≤ 0.02% and the total mass of impurities ≤ 0.1%; the aluminum alloy grains are distributed in a streamline fiber structure, and the size of the aluminum alloy grains is 34.9 μm-54 μm; the aluminum alloy matrix contains uniformly distributed Al3Sc precipitation phases, and the Al3Sc precipitation phases are coherent with the aluminum alloy matrix. The present application obtains an extruded aluminum alloy profile with high strength and toughness and excellent performance, greatly improving the forming performance and mechanical properties of the aluminum alloy.

Description

Technical Field

[0001] This application belongs to the technical field of aluminum alloys, and relates to an aluminum alloy profile, specifically to a high-strength and tough new aluminum alloy profile, its manufacturing method, and a battery pack box body made of the aluminum alloy profile, a battery pack including the battery pack box body, and an electrical device. Background Art

[0002] Since the 21st century, lighter materials have been one of the ways to effectively reduce environmental pollution and energy consumption. Aluminum alloys have the advantages of low density, good corrosion resistance and formability, excellent welding performance, etc., and are one of the most ideal materials in the lightweight development routes of automobiles, airplanes, and aerospace. The body mass can be effectively reduced by using lightweight and high-performance aluminum alloys instead of traditional steel parts, reducing automotive energy consumption and exhaust emissions. The design of new automobiles, airplanes, and aerospace vehicles has put forward higher requirements for the optimal combination of the strength and corrosion resistance of aluminum alloy structural materials. Especially with the introduction of a large number of new high-performance airplanes on trunk routes, it is more necessary to develop and produce new aluminum alloy structural materials with higher strength, fracture toughness performance meeting requirements, and better corrosion resistance to meet the material selection of China's aircraft design and manufacturing departments. With the development of new energy vehicles, the demand for large-size power battery modules has increased significantly. Aluminum alloys are widely used due to their easy formability, excellent comprehensive machining performance, good corrosion resistance, light specific gravity and moderate strength. The battery pack box body material should have characteristics such as electrical insulation, high heat dissipation, and chemical stability. The box body is generally composed of an upper box body, a lower box body, and a sealing system. The mass of the battery pack accounts for 18% - 30% of the total mass of the vehicle system, and the mass of the box body accounts for about 10% - 20% of the total mass of the battery pack. With the in-depth implementation of the concept of automotive lightweight design, aluminum alloys have gradually become the main materials for achieving automotive lightweight due to their advantages such as low density, high stiffness and strength, and good die-casting performance. Currently, products such as cast aluminum battery boxes, aluminum sheet battery boxes, and aluminum profile battery boxes have been produced. Among them, the load-bearing structures of aluminum battery pack boxes are mainly divided into bottom plate type and frame type. However, nowadays, traditional aluminum alloys have the disadvantages of coarse grains, low recrystallization temperature, high strength but insufficient fracture toughness. Moreover, due to their general heat resistance performance, traditional aluminum alloys will invisibly increase the power transmission loss and load of the system.

[0003] Therefore, there is an urgent need in this field for an improved method to overcome the above-mentioned defects of the prior art and improve the performance of Al-Mg-Sc alloys. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, this application improves the performance of Al-Mg-Sc alloys by adding a specific amount of Sc and adopting a specific manufacturing process.

[0005] According to the first aspect of the present application, an aluminum alloy profile is provided. In terms of mass percentage, the aluminum alloy profile comprises the following components: 0.6 - 1.3% Si, 0.6 - 1.0% Mg, 0.6 - 0.73% Fe, 0.05 - 0.2% Cu, 0.1 - 0.2% Mn, and 0.14 - 0.30% Sc, with the balance being Al and impurities, where the mass of a single impurity ≤ 0.02% and the total mass of impurities ≤ 0.1%;

[0006] The aluminum alloy grains are distributed in a streamlined fibrous structure, and the size of the aluminum alloy grains is 34.9 μm - 54 μm;

[0007] The aluminum alloy matrix contains uniformly distributed Al3Sc precipitation phases, and the Al3Sc precipitation phases are coherent with the aluminum alloy matrix.

[0008] In the present application, the aluminum alloy profile has fine grains, a long strip fibrous structure, and significantly improved forming performance and mechanical properties, including higher yield strength, tensile strength, and elongation. And the interface between Al3Sc and the aluminum alloy matrix is coherent, enabling the aluminum alloy profile to have good thermodynamic properties and strengthening effects.

[0009] In any implementation, the aluminum alloy profile contains 0.14 - 0.20% Sc, which can further achieve grain refinement.

[0010] In any implementation, the radius of the Al3Sc precipitation phase remains within the range of 4 - 10 nm. When the radius of the Al3Sc precipitation phase is within the above range, it can hinder the movement of dislocations, prevent the merger of sub-grain boundaries, and the migration and displacement of grain boundaries, playing a role in precipitation strengthening.

[0011] According to the second aspect of the present application, a manufacturing method of an aluminum alloy profile is provided, including:

[0012] (1) Mixing intermediate alloys Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc with 99.9 mass% pure magnesium ingots and 99.9 mass% pure aluminum ingots to obtain a solid mixture;

[0013] (2) Heating the solid mixture obtained in step (1) until it melts, then holding the temperature and stirring evenly, and then standing to obtain a molten mixture;

[0014] (3) Performing refining treatment on the molten mixture obtained in step (2), where the molten mixture is sub-packaged and stirred, then standing after refining treatment, and pouring is completed after the temperature drops to meet the requirements of the mirror sample to obtain an aluminum alloy ingot;

[0015] (4) The aluminum alloy ingot obtained in step (3) is subjected to single-stage homogenization treatment and then rapidly cooled to room temperature to obtain a homogenized aluminum alloy ingot;

[0016] (5) The homogenized aluminum alloy ingot obtained in step (4) is heated and held at a certain temperature, the extrusion die is preheated, and then a hot extrusion process of a one-mode two-hole split die is carried out, and then cooled to room temperature;

[0017] (6) The extruded aluminum alloy profile cooled to room temperature obtained in step (5) is subjected to a cold bending and straightening process, and:

[0018] (7) The aluminum alloy profile obtained in step (6) is subjected to heat treatment of solution treatment and artificial aging to obtain an aluminum alloy profile.

[0019] Wherein, by mass percentage, the aluminum alloy profile comprises the following components: 0.6-1.3% Si, 0.6-1.0% Mg, 0.6-0.73% Fe, 0.05-0.2% Cu, 0.1-0.2% Mn and 0.14-0.30% Sc, the balance being Al and impurities, wherein the mass of a single impurity ≤ 0.02%, and the total mass of impurities ≤ 0.1%;

[0020] The aluminum alloy grains are distributed in a streamline fiber structure, and the size of the aluminum alloy grains is 34.9 μm - 54 μm;

[0021] The aluminum alloy matrix contains uniformly distributed Al3Sc precipitation phases, and the Al3Sc precipitation phases are coherent with the aluminum alloy matrix.

[0022] In this application, based on the Al-Mg-Si series aluminum alloy, a specific amount of Sc is added to the original main elements Al, Si, and Mg elements to increase the recrystallization temperature, inhibit recrystallization, grain growth, and refine grains; using a specific amount of Sc makes the precipitation phase Al3Sc with a smaller misfit degree precipitate during the casting process, which can act as a heterogeneous nucleating agent, significantly increase the nucleation rate, effectively reduce the grain size, and achieve fine grain strengthening; in addition, the precipitation phase Al3Sc hinders the movement of dislocations, prevents the merger of sub-boundaries and the migration of grain boundaries, and plays a role in precipitation strengthening; a hot extrusion process of a one-mode two-hole split die is adopted to improve the production efficiency of the extruder and the service life of the die; and a solution treatment + artificial aging process after extrusion is adopted to improve the forming performance and transverse and longitudinal strength of the aluminum alloy.

[0023] In the embodiment of this application, in step (2), the heating temperature is not lower than 700 °C, the holding temperature is 710 °C - 720 °C, the stirring time is 25 - 30 minutes, and the standing time is 10 - 15 minutes.

[0024] In the present application, appropriate heating temperature, holding temperature, stirring time, and standing time are adopted in step (2), ensuring the obtaining of appropriate molten material.

[0025] In an embodiment of the present application, in step (3), the refining agent includes: hexachloroethane, a mixture of KCl, NaCl, and Na3AlF6, and a mixture of KCl, MgCl2, and CaF2, and the addition amount thereof is 0.5 - 0.8% based on the mass of the molten material; the stirring time is 10 - 15 minutes; the temperature of the refining treatment is 730 - 740 °C; the standing time is 15 - 20 minutes; pouring is completed when the temperature drops to 720 - 730 °C.

[0026] In the present application, appropriate addition amount of the refining agent, refining temperature, stirring time, temperature of the refining treatment, standing time, and pouring temperature are adopted in step (3), ensuring the obtaining of the required forming performance and grain size.

[0027] In an embodiment of the present application, in step (4), single-stage homogenization treatment is carried out in a high-temperature furnace; wherein, the holding temperature is 460 °C - 470 °C, and the holding time is 20 - 24 hours.

[0028] In the present application, appropriate holding temperature and holding time are adopted in step (4), ensuring the obtaining of the required grain size and distribution.

[0029] In an embodiment of the present application, in step (5), it is cooled to room temperature by the way of flowing water; wherein, the heating temperature is 450 °C - 500 °C, the holding time is 1.5 - 2 hours, the preheating temperature is 450 °C - 460 °C, and the extrusion rate is 120 - 140 mm / minute.

[0030] In the present application, appropriate cooling method, heating temperature, holding time, preheating temperature, and extrusion rate are adopted in step (5), ensuring the progress of the hot extrusion process of the one-mold two-hole split die, and improving the production efficiency of the extruder and the service life of the die.

[0031] In an embodiment of the present application, in step (7), the temperature of the solution treatment is 550 - 560 °C, and the holding time is 1 - 2 hours; the temperature of the artificial aging is 140 - 175 °C, and the holding time is 10 - 12 hours, and the interval time between the solution treatment and the artificial aging does not exceed 2 hours.

[0032] In the present application, appropriate temperature of the solution treatment, holding time, temperature of the artificial aging, and interval time between the solution treatment and the artificial aging are adopted in step (7), ensuring the progress of the solution treatment + artificial aging process, and improving the forming performance and transverse and longitudinal strength of the aluminum alloy.

[0033] According to a third aspect of the present application, there is provided a battery pack housing, which is made of the above-mentioned aluminum alloy profiles or the aluminum alloy profiles prepared by the above method.

[0034] According to a fourth aspect of the present application, there is provided a battery pack, which includes the above-mentioned battery pack housing.

[0035] According to a fifth aspect of the present application, there is provided an electrical device, which includes the above-mentioned battery pack, and the battery pack is used as a power source or an energy storage unit of the electrical device.

[0036] Compared with the prior art, the improved method of the present application obtains extruded aluminum alloy profiles with high strength, toughness and excellent performance, and greatly improves the forming performance and mechanical properties of the aluminum alloy.

[0037] These and other features and advantages will become apparent by reading the following detailed description and referring to the associated drawings. It should be understood that the foregoing general description and the following detailed description are illustrative only and do not limit the various aspects claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic diagram of an embodiment of the battery pack housing of the present application.

[0039] Figure 2 is a schematic diagram of an embodiment of the battery pack of the present application.

[0040] Figure 3 is Figure 2 an exploded view of the shown battery pack.

[0041] Figure 4 is a schematic diagram of an embodiment of a device using the battery pack of the present application as a power source.

[0042] Figure 5 is the mechanical property curve of various aluminum alloy profiles after split die extrusion heat treatment according to the embodiments of the present application.

[0043] Figure 6 is the SEM (scanning electron microscope) microstructural image of the JNL-3 alloy after heat treatment according to Example 3 of the present application.

[0044] Description of the reference numerals:

[0045] 1. Battery pack housing

[0046] 1-1. Longitudinal beam of the battery pack housing

[0047] 1-2. Cross beam of the battery pack housing

[0048] 1-3. Front beam of the battery pack housing

[0049] 1-4. Rear beam of the battery pack housing

[0050] 11. Lower housing

[0051] 12. Upper housing

[0052] 3. Battery cell

[0053] 4. Motor

[0054] 5. Controller Detailed implementation manners

[0055] The present application will be described in detail below with reference to the accompanying drawings, and the features of the present application will be further revealed in the following detailed description.

[0056] The "ranges" disclosed herein are defined in the form of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a particular range. The ranges defined in this way can include the end values or not, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, ranges of 60-110 and 80-120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In the present application, unless otherwise specified, the numerical range "a-b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been fully listed herein, and "0-5" is only an abbreviated representation of these numerical combinations. Additionally, when stating that a certain parameter is an integer ≥2, it is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0057] In the present application, unless otherwise specified, all the implementation manners and preferred implementation manners mentioned herein can be combined with each other to form a new technical solution. In the present application, unless otherwise specified, all the technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0058] In the present application, unless otherwise specified, the "including" and "comprising" mentioned herein mean open-ended or can also be closed-ended. For example, the "including" and "comprising" can mean that other components not listed can also be included or comprised, or can only include or comprise the listed components.

[0059] In the description of this article, unless otherwise specified, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0060] Existing aluminum alloys have the disadvantages of coarse grains, low recrystallization temperature, high strength but insufficient fracture toughness. Moreover, due to their general heat resistance, traditional aluminum alloys will inadvertently increase the power transmission loss and load of the system; and aluminum alloys have a high density of precipitation strengthening phases rather than fibrous dispersion phases, resulting in poor mechanical properties and low strength. By adding a small amount of rare earth element Sc, the scandium-containing aluminum alloy can form Al3Sc particles in the melt during solidification, acting as a heterogeneous nucleation core for aluminum during the nucleation process, significantly increasing the nucleation rate and refining the grains. Moreover, inside the Al3Sc particles, a coarse dendritic structure is formed on the (111) plane and the (110) plane, and a large number of cellular structures are formed on the (100) plane. At the interface between Al3Sc and the Al matrix, there are two parallel crystallographic structures, and the atomic arrangement on both sides of the interface is the same. At the same time, a special pseudomorphic solid (PS) layer is observed at the interface. On the (111) crystal plane, the atomic arrangement of the PS layer and Al3Sc forms a 60° angle with Al, refining the grains. However, due to the pores, inclusions, and sand holes generated during semi-continuous casting, the mechanical properties of the as-cast Al-Mg-Sc alloy cannot meet the performance requirements in industry, so it is necessary to further improve the preparation process of the Al-Mg-Sc alloy.

[0061] To address the above-mentioned deficiencies in the prior art, this application further improves the manufacturing process of Al-Mg-Sc alloy, and proposes a manufacturing method for a high-strength and tough new aluminum alloy profile. Based on the Al-Mg-Si series aluminum alloy, a specific content of Sc is added to the original main elements Al, Si, and Mg to increase the recrystallization temperature, inhibit recrystallization, grain growth, and refine grains. Subsequently, the preparation of the new Al-Mg-Sc alloy and the optimization of the forming process are carried out, including: first, melting various pure metal ingots and master alloys in an aluminum alloy melting furnace, and completing the processes of spray refining, degassing and impurity removal, semi-continuous casting, and trimming and peeling slag; then, performing a hot extrusion process on the as-cast new Al-Mg-Sc alloy. To improve the production efficiency of the extruder and the service life of the die, a split die with two holes in one die is used as the extrusion die; then, solution treatment and aging process are carried out to finally obtain a new Al-Mg-Sc alloy with fine grains and a long strip fibrous structure. Due to the presence of Sc element, precipitation phase Al3Sc with a small misfit degree is precipitated during the casting process, which can act as a heterogeneous nucleating agent, significantly increase the nucleation rate, effectively reduce the grain size, and achieve fine grain strengthening. In addition, the precipitated phase Al3Sc hinders the movement of dislocations, prevents the merger of sub-grain boundaries and the migration of grain boundaries, and plays a role in precipitation strengthening. Through the solution treatment + aging process after extrusion, the forming performance and transverse and longitudinal strength of the aluminum alloy are improved, and the obtained aluminum alloy is suitable for the manufacturing of the fuselage and body of lightweight aircraft, automobiles and other transportation tools, as well as the lithium battery box body.

[0062] In addition, the inventors of the present application found that in current major studies, rare earth element Sc is added to aluminum alloy to increase the nucleation free energy of Al. By changing the morphology of eutectic Si, strengthening is achieved through modification and heterogeneous nucleation. Usually, when the addition amount is less than 0.1% by weight, the strengthening mechanism is dominated by solid solution strengthening, while when it is greater than 0.3% by weight, it is dominated by the second phase, and intermediate metal compounds such as Al3Y are generated to achieve second-phase strengthening. In the present application, when the addition amount of Sc is greater than 0.3% by weight, it will cause the formed intermediate compound to grow, resulting in coarse second phases at the grain boundaries, leading to a decrease in the interfacial bonding force between the Al matrix and the second phase, thus significantly reducing the room-temperature mechanical properties. In other words, adding a small amount of Sc can hinder the aggregation and combination of aluminum atoms, increase the acting force of aluminum atoms, and strengthen the alloy as fine phases segregated at the grain boundaries. Therefore, in the present application, the addition amount of Sc is limited between 0.1 and 0.30% by weight, optionally between 0.14 and 0.20% by weight. In addition, the extrusion method of rare earth aluminum alloy used by domestic agent factories is mostly ordinary extrusion dies, with an extrusion ratio of 60 - 70. However, in the present application, in order to extend the service life of the die itself, diversify the functions of the profiles, and improve the efficiency of the extruder, a split die extrusion with one die and two holes for flow splitting is adopted. Moreover, in the heat treatment system of commonly used Al-Mg-Si series extruded aluminum alloys in China, artificial aging treatment is carried out by holding at 170 - 180°C for 8 - 10 hours. However, due to the fact that the precipitation strengthening mechanism does not play an obvious role in Sc-containing aluminum alloys, artificial aging at high temperatures not only fails to achieve traditional precipitation strengthening, but instead causes abnormal growth of second phases such as Al3S, resulting in coarse second phases being precipitated, significantly reducing the mechanical properties and forming properties in the transverse and longitudinal directions, and leading to early failure of the workpiece. In the present application, a specific solution treatment + artificial aging process is adopted, improving the forming properties and mechanical properties in the transverse and longitudinal directions of the aluminum alloy.

[0063] The aluminum alloy profiles prepared in the present application have fine grains, and the structure is in the shape of long strips and fibers, and have significantly improved forming properties and mechanical properties, including higher yield strength, tensile strength, and elongation rate, and are suitable for the manufacture of the fuselage and body of lightweight aircraft, automobiles and other transportation tools, as well as the frames of lithium batteries.

[0064] Aluminum alloy profiles

[0065] In the present application, by mass percentage, the aluminum alloy profiles comprise the following components: 0.6 - 1.3% Si, 0.6 - 1.0% Mg, 0.6 - 0.73% Fe, 0.05 - 0.2% Cu, 0.1 - 0.2% Mn, and 0.14 - 0.30% Sc, with the balance being Al and impurities, where the mass of a single impurity ≤ 0.02% and the total mass of impurities ≤ 0.1%;

[0066] The aluminum alloy grains are flattened and elongated along the extrusion axis direction, showing a streamline fiber structure distribution, and the size of the aluminum alloy grains is 34.9μm - 54μm;

[0067] The aluminum alloy matrix contains uniformly distributed Al3Sc precipitation phases, and the Al3Sc precipitation phases are coherent with the aluminum alloy matrix. In this application, the aluminum alloy profiles have fine grains, a long strip fiber-like structure, and significantly improved forming performance and mechanical properties, including higher yield strength, tensile strength, and elongation. And the interface between Al3Sc and the aluminum alloy matrix is coherent, making the aluminum alloy profiles have good thermodynamic properties and strengthening effects.

[0068] In any embodiment, the aluminum alloy profiles contain 0.14 - 0.20% Sc, which can further refine the grains of the aluminum alloy profiles.

[0069] In any embodiment, the Al3Sc precipitation phases are very stable, and their radius remains within the range of 4 - 10nm. When the radius of the Al3Sc precipitation phases is within the above range, it can hinder the movement of dislocations, prevent the merging of sub-grain boundaries, and the migration and displacement of grain boundaries, playing a role in precipitation strengthening.

[0070] The aluminum alloy profiles of this application are suitable for manufacturing battery pack boxes, and the battery pack containing this battery pack box can be used as a power source or energy storage unit of an electrical device. The electrical devices include but are not limited to mobile digital devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, satellites, energy storage systems, etc.

[0071] Manufacturing method of aluminum alloy profiles

[0072] In this application, the manufacturing method of aluminum alloy profiles includes:

[0073] (1) Mix intermediate alloys Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc with 99.9 mass% pure magnesium ingots and 99.9 mass% pure aluminum ingots to obtain a solid mixture;

[0074] (2) Heat the solid mixture obtained in step (1) until it melts, keep it warm, stir it evenly, and then let it stand to obtain a molten mixture;

[0075] (3) Refine the molten mixture obtained in step (2). Specifically, divide the molten mixture into portions and stir it, let it stand after refining, and complete casting after the temperature drops to meet the requirements of the mirror sample to obtain an aluminum alloy ingot;

[0076] (4) The aluminum alloy ingot obtained in step (3) is subjected to single-stage homogenization treatment, and then rapidly cooled to room temperature to obtain a homogenized aluminum alloy ingot;

[0077] (5) The homogenized aluminum alloy ingot obtained in step (4) is heated and held at a certain temperature, the extrusion die is preheated, and then a hot extrusion process of a one-mold two-hole split die is carried out, and then cooled to room temperature;

[0078] (6) The extruded aluminum alloy profile cooled to room temperature obtained in step (5) is subjected to a cold bending and straightening process, and:

[0079] (7) The aluminum alloy profile obtained in step (6) is subjected to heat treatment of solution treatment and artificial aging to obtain an aluminum alloy profile.

[0080] Among them, by mass percentage, the aluminum alloy profile contains the following components: 0.6-1.3% Si, 0.6-1.0% Mg, 0.6-0.73% Fe, 0.05-0.2% Cu, 0.1-0.2% Mn, and 0.14-0.30% Sc, and the balance is Al and impurities, where the mass of a single impurity ≤ 0.02%, and the total mass of impurities ≤ 0.1%;

[0081] The aluminum alloy grains are distributed in a streamline fiber structure, and the size of the aluminum alloy grains is 34.9 μm - 54 μm;

[0082] The aluminum alloy matrix contains uniformly distributed Al3Sc precipitate phases, and the Al3Sc precipitate phases are coherent with the aluminum alloy matrix.

[0083] In this application, based on the Al-Mg-Si series aluminum alloy, a specific amount of Sc is added to the original main elements Al, Si, and Mg to increase the recrystallization temperature, inhibit recrystallization, grain growth, and refine grains; using a specific amount of Sc makes the precipitation phase Al3Sc with a small misfit degree precipitate during the casting process, which can act as a heterogeneous nucleating agent, significantly increase the nucleation rate, effectively reduce the grain size, and achieve fine grain strengthening; in addition, the precipitate phase Al3Sc hinders the movement of dislocations, prevents the merger of sub-grain boundaries and the migration of grain boundaries, and plays a role in precipitation strengthening; adopting a hot extrusion process of a one-mold two-hole split die improves the production efficiency of the extruder and the service life of the die; and adopting a solution treatment + artificial aging process after extrusion improves the forming performance and transverse and longitudinal strength of the aluminum alloy, and prepares an aluminum alloy profile that meets the industrial performance requirements.

[0084] In an embodiment of the present application, in step (2), the solid ingredients are placed into a graphite crucible of a 10-ton aluminum alloy melting furnace, heated to melt the solid aluminum alloy, kept warm and stirred with an iron stirring rod, and left to stand after being stirred evenly; wherein, the heating temperature is not lower than 700 °C, the holding temperature is 710 °C - 720 °C, so as to prevent the manufacturing defect of doped slag floating due to the low temperature of the molten aluminum; the stirring time is 25 - 30 minutes, and the standing time is 10 - 15 minutes; optionally, this process requires keeping the inside and outside of the melting furnace clean and stirring under a nitrogen atmosphere.

[0085] In the present application, in step (2), appropriate heating temperature, holding temperature, stirring time and standing time are adopted to ensure obtaining appropriate molten material.

[0086] In an embodiment of the present application, in step (3), the refining agent includes: hexachloroethane, a mixture of KCl, NaCl and Na3AlF6, and a mixture of KCl, MgCl2 and CaF2, and its addition amount is 0.5 - 0.8%, based on the mass of the molten material; the material is sub-packaged by aluminum foil paper, the stirring time is 10 - 15 minutes; the temperature of the refining treatment is 730 - 740 °C; the standing time is 15 - 20 minutes; pouring is completed when the temperature drops to 720 - 730 °C.

[0087] In the present application, in step (3), appropriate addition amount of the refining agent, refining temperature, stirring time, temperature of the refining treatment, standing time and pouring temperature are adopted to ensure obtaining the required forming properties and grain size.

[0088] In an embodiment of the present application, in step (4), single-stage homogenization treatment is carried out in a high-temperature furnace; wherein, the holding temperature is 460 °C - 470 °C, and the holding time is 20 - 24 hours; it is cooled to room temperature by a water reservoir.

[0089] In the present application, in step (4), appropriate holding temperature and holding time are adopted to ensure obtaining the required grain size and distribution.

[0090] In an embodiment of the present application, in step (5), it is cooled to room temperature by a water flow-through method; wherein, the heating temperature is 450 °C - 500 °C, the holding time is 1.5 - 2 hours, the preheating temperature is 450 °C - 460 °C, and the extrusion rate is 120 - 140 mm / minute; the hot extrusion process of a one-mode two-hole split die is completed by a horizontal extruder.

[0091] In this application, in step (5), by adopting appropriate cooling methods, heating temperatures, heat preservation times, preheating temperatures, and extrusion rates, the hot extrusion process of the one-mold two-hole split die is ensured, and the production efficiency of the extruder and the service life of the die are improved.

[0092] In an embodiment of this application, in step (6), a cold bending and straightening process is carried out by a robotic arm to facilitate the next heat treatment process.

[0093] In an embodiment of this application, in step (7), a heat treatment process of solution treatment + artificial aging is carried out in a high-temperature furnace and a low-temperature furnace. Among them, the temperature of the solution treatment is 550 - 560 °C, and the heat preservation time is 1 - 2 hours; the temperature of artificial aging is 140 - 175 °C, and the heat preservation time is 10 - 12 hours, and the interval time between the solution treatment and artificial aging does not exceed 2 hours.

[0094] In this application, in step (7), by adopting appropriate solution treatment temperatures, heat preservation times, artificial aging temperatures, and the interval time between the solution treatment and artificial aging, the solution treatment + artificial aging process is ensured, and the forming performance and transverse and longitudinal strengths of the aluminum alloy are improved.

[0095] Battery pack box body

[0096] In an embodiment of this application, the battery pack box body can be manufactured from the above aluminum alloy profiles or aluminum alloy profiles prepared by the above method.

[0097] Figure 1 is a schematic diagram of an embodiment of the battery pack box body of this application. As Figure 1 shown, (a) is the top view of the battery pack box body, (b) is the front view of the battery pack box body, (c) is the cross-sectional view of each beam of the battery pack box body. The battery pack box body 1 includes longitudinal beams 1-1, cross beams 1-2, front beams 1-3, and rear beams 1-4. Each beam forms an accommodation space for accommodating battery cells.

[0098] Battery pack

[0099] In an embodiment of this application, the battery pack includes the above battery pack box body.

[0100] Figure 2 is a schematic diagram of an embodiment of the battery pack of this application. Figure 3 is Figure 2 the exploded view of the battery pack shown. As Figure 2-3As shown, the battery pack 2 includes battery cells 3 and a battery pack housing 1, and the battery cells 3 are accommodated in the battery pack housing 1. Among them, the battery pack housing 1 is used to provide an accommodation space for the battery cells 3. The battery pack housing 1 can adopt various structures. In some examples, the battery pack housing 1 can include a lower housing 11 and an upper housing 12. The lower housing 11 and the upper housing 12 are covered with each other to jointly define an accommodation space for accommodating the battery cells 3. The lower housing 11 can be a hollow structure with one end open, and the upper housing 12 can be a plate-like structure. The upper housing 12 is covered on the open side of the lower housing 11 so that the lower housing 11 and the upper housing 12 jointly define an accommodation space. The lower housing 11 and the upper housing 12 can also both be hollow structures with one side open, and the open side of the upper housing 12 is covered on the open side of the lower housing 11. Of course, the battery pack housing 1 formed by the lower housing 11 and the upper housing 12 can be of various shapes, such as a cylinder, a cuboid, etc.

[0101] electrical device

[0102] In one embodiment of the present application, the electrical device of the present application includes the battery pack of the present application. The battery pack can be used as the power source of the electrical device or as the energy storage unit of the electrical device. The electrical device includes but is not limited to mobile digital devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, satellites, energy storage systems, etc.

[0103] Figure 4 It is a schematic diagram of an embodiment of a device using the battery pack of the present application as a power source. As an example device, it can be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the requirements of the device for high power and high energy density, a battery pack can be adopted.

[0104] As Figure 4 As shown, the vehicle can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc. A battery pack 2, a controller 5, and a motor 4 can be arranged inside the vehicle. The controller 5 is used to control the battery pack 2 to supply power to the motor 4. For example, the battery pack 2 can be arranged at the bottom, the front of the vehicle, or the rear of the vehicle. The battery pack 2 can be used for power supply of the vehicle. For example, the battery pack 2 can be used as the operating power source of the vehicle for the vehicle's circuit system, such as for the power consumption requirements during the start, navigation, and operation of the vehicle.

[0105] In another example of the present application, the battery pack 2 can not only be used as the operating power source of the vehicle but also as the driving power source of the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0106] As another example of the device, it can be a mobile phone, a tablet computer, a laptop computer, etc. This device usually requires being thin and light, and a secondary battery can be used as the power source.

[0107] In the following, the battery pack box manufactured according to the implementation mode of the present application is characterized based on specific embodiments. However, it should be specifically pointed out that the protection scope of the present application is defined by the claims, and is not limited to the above specific implementation modes.

[0108] I. Embodiment

[0109] Unless otherwise specified, the raw materials used in the present application are all of analytical purity, and the water is all deionized water.

[0110] Embodiment 1

[0111] Taking the Al-Mg-Si series aluminum alloy as an example, the new high-strength and high-toughness aluminum alloy of the present application is manufactured, numbered JNL-1. The specific steps are as follows:

[0112] In the first step, the Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc, pure magnesium ingots with a mass percentage of 99.9%, and 99.9% pure aluminum ingots are calculated and selected according to the corresponding batching ratios.

[0113] In the second step, the corresponding solid-state ingredients are put into a graphite crucible of a 10-ton aluminum alloy melting furnace, heated to 700°C to melt the solid-state aluminum alloy, kept at 710°C and stirred with an iron stirring rod for 25 minutes, and then left to stand for 10 minutes after being stirred evenly; during this process, attention needs to be paid to the cleanliness inside and outside the melting furnace and stirring is carried out under a nitrogen atmosphere.

[0114] In the third step, refining treatment after heating up is carried out while keeping the temperature at 710°C, so as to prevent the manufacturing defect of doped slag caused by the slag floating up due to the low temperature of the aluminum liquid. Among them, the refining temperature is 736°C, the refining agent is hexachloroethane, and the addition ratio is 0.6%; the material is sub-packed with aluminum foil paper and stirred for 15 minutes, left to stand for 17 minutes after refining, and pouring is completed when the temperature drops to 724°C.

[0115] After the above process steps are completed, the chemical composition of the alloy is detected. The specific chemical composition (mass percentage) is as follows: 0.63% Si, 0.69% Mg, 0.62% Fe, 0.18% Cu, 0.20% Mn, 0.14% Sc. Then, a single-stage homogenization treatment is carried out in a high-temperature furnace at 460 °C for 20 hours. After that, it is quickly cooled to room temperature through a water reservoir. The homogenized aluminum alloy ingot is heated to 455 °C, held for 1.5 hours, and the extrusion die is preheated. Subsequently, the hot extrusion process of the porthole die is completed through a horizontal extrusion press, and it is cooled to room temperature by using the water-through spraying method. The extrusion parameters are as follows: the die temperature is 450 °C, and the extrusion speed is 140 mm / minute. Subsequently, the extruded aluminum alloy profile cooled to room temperature is subjected to a cold bending and straightening process by a robotic arm and then sawed into small segments. Finally, the extruded new aluminum alloy is subjected to a heat treatment process of solution treatment + artificial aging in a high-temperature furnace and a low-temperature furnace. The solution treatment process is a high-temperature short-time solution method of holding at 550 °C for 1 hour, and the aging process is an artificial aging treatment method of holding at 150 °C for 12 hours. The interval time between the solution treatment and the artificial aging is 1 hour.

[0116] Example 2

[0117] Taking the Al-Mg-Si series aluminum alloy as an example, the new high-strength and high-toughness aluminum alloy of the present application is manufactured, numbered JNL-2. The specific steps are as follows:

[0118] First step, calculate and select the above-mentioned Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc, and pure magnesium ingots with a mass percentage of 99.9% and pure aluminum ingots with a mass percentage of 99.9% according to the corresponding batching ratios.

[0119] Second step, put the corresponding solid ingredients into a graphite crucible of a 10-ton aluminum alloy melting furnace, heat to 700 °C to melt the solid aluminum alloy, hold at 710 °C and stir it with an iron stirring rod for 25 minutes, and let it stand for 10 minutes after stirring evenly; during this process, attention needs to be paid to the cleanliness inside and outside the melting furnace and stirring under a nitrogen atmosphere.

[0120] Third step, carry out a refining treatment after heating up while holding at 710 °C to prevent the manufacturing defect of doped slag caused by the low temperature of the molten aluminum resulting in the floating of the slag. The refining temperature is 737 °C, and the refining agent selected is hexachloroethane, with an addition ratio of 0.8%; the material is packaged in sub-packages with aluminum foil paper and stirred for 15 minutes, and after refining, it is left standing for 18 minutes, and pouring is completed when the temperature drops to 725 °C.

[0121] After the above process steps are completed, the chemical composition of the alloy is detected. The specific chemical composition (mass percentage) is as follows: 0.62% Si, 0.49% Mg, 0.64% Fe, 0.18% Cu, 0.14% Mn, 0.29% Sc.

[0122] Then, a single-stage homogenization treatment is carried out in a high-temperature furnace at 460 °C for 20 hours. After that, it is quickly cooled to room temperature through a water reservoir. The homogenized aluminum alloy ingot is heated to 455 °C, held for 1.5 hours, and the extrusion die is preheated. Subsequently, the hot extrusion process of the porthole die is completed through a horizontal extrusion machine, and it is cooled to room temperature by using the water-through spraying method. The extrusion parameters are as follows: the die temperature is 450 °C, and the extrusion speed is 140 mm / minute. Subsequently, the extruded aluminum alloy profile cooled to room temperature is subjected to a cold bending and straightening process by a robotic arm and then sawed into small segments. Finally, the extruded new aluminum alloy is subjected to a heat treatment process of solution treatment + artificial aging in a high-temperature furnace and a low-temperature furnace. The solution treatment process is a high-temperature short-time solution method of holding at 550 °C for 1 hour, and the aging process is an artificial aging treatment method of holding at 150 °C for 12 hours. The artificial aging treatment is carried out 1 hour after the solution treatment is postponed.

[0123] Example 3

[0124] Taking the Al-Mg-Si series aluminum alloy as an example, the new high-strength and high-toughness aluminum alloy of the present application is manufactured, numbered JNL-3. The specific steps are as follows:

[0125] First step, calculate and select the Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc, and pure magnesium ingots with a mass percentage of 99.9% and pure aluminum ingots with a mass percentage of 99.9% according to the corresponding batching ratios.

[0126] Second step, put the corresponding solid ingredients into a graphite crucible of a 10-ton aluminum alloy melting furnace, heat to 700 °C to melt the solid aluminum alloy, hold at 710 °C and stir it with an iron stirring rod for 25 minutes, and let it stand for 10 minutes after stirring evenly; during this process, attention should be paid to the cleanliness inside and outside the melting furnace and stirring under a nitrogen atmosphere.

[0127] Third step, carry out a refining treatment after heating up when holding at 710 °C, so as to prevent the manufacturing defect of doped slag caused by the low temperature of the aluminum liquid resulting in the floating of the slag. The refining temperature is 737 °C, the refining agent selected is hexachloroethane, and the addition ratio is 0.8%. The material is packaged in aluminum foil paper and stirred for 15 minutes. After refining, let it stand for 18 minutes, and complete the casting when the temperature drops to 725 °C.

[0128] After the above process steps are completed, the chemical composition of the alloy is detected. The specific chemical composition (mass percentage) is as follows: 1.00% Si, 0.68% Mg, 0.73% Fe, 0.087% Cu, 0.19% Mn, 0.19% Sc.

[0129] Then, a single-stage homogenization treatment is carried out in a high-temperature furnace at 460 °C for 20 hours. After that, it is quickly cooled to room temperature through a water reservoir. The homogenized aluminum alloy ingot is heated to 455 °C and held for 1.5 hours, and the extrusion die is preheated. Subsequently, the hot extrusion process of the porthole die is completed through a horizontal extrusion machine, and water mist spraying cooling is used. The temperature of the extrusion die is 450 °C, and the extrusion speed is 140 mm / minute. Subsequently, the extruded aluminum alloy profile cooled to room temperature is subjected to a cold bending and straightening process by a robotic arm and then sawed into small segments. Finally, the extruded new aluminum alloy is subjected to a heat treatment process of solution treatment + artificial aging in a high-temperature furnace and a low-temperature furnace. The solution treatment process is a high-temperature short-time solution method of holding at 550 °C for 1 hour, and the aging process is an artificial aging treatment method of holding at 150 °C for 12 hours. Artificial aging treatment is carried out quickly 1 hour after solution treatment.

[0130] Example 4

[0131] Taking the Al-Mg-Si series aluminum alloy as an example, the new high-strength and tough aluminum alloy of the present application is manufactured, numbered JNL-4. The specific steps are as follows:

[0132] In the first step, the Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc, and pure magnesium ingots with a mass percentage of 99.9% and pure aluminum ingots with a mass percentage of 99.9% are calculated and selected according to the corresponding batching ratios.

[0133] In the second step, the corresponding solid-state ingredients are placed in a graphite crucible of a 10-ton aluminum alloy melting furnace and heated to 700 °C to melt the solid-state aluminum alloy. It is held at 710 °C and stirred with an iron stirring rod for 25 minutes. After stirring evenly, it is left standing for 10 minutes; during this process, attention needs to be paid to the cleanliness inside and outside the melting furnace and stirring is carried out under a nitrogen atmosphere.

[0134] In the third step, a refining treatment after temperature rise is carried out while holding at 710 °C to prevent the manufacturing defect of doped slag floating due to the low temperature of the aluminum liquid. The refining temperature is 737 °C, and the refining agent selected is hexachloroethane, and the addition ratio is 0.8%. The material is packaged in aluminum foil paper and stirred for 15 minutes. After refining, it is left standing for 18 minutes, and pouring is completed when the temperature drops to 725 °C.

[0135] After the above process steps are completed, the chemical composition of the alloy is detected. The specific chemical composition (mass percentage) is as follows: 1.00% Si, 0.68% Mg, 0.73% Fe, 0.087% Cu, 0.19% Mn, 0.19% Sc.

[0136] Then, a single-stage homogenization treatment is carried out in a high-temperature furnace at 460 °C for 20 hours. After that, it is quickly cooled to room temperature through a water reservoir. The homogenized aluminum alloy ingot is heated to 455 °C, held for 1.5 hours, and the extrusion die is preheated. Subsequently, the hot extrusion process of the porthole die is completed through a horizontal extrusion machine, and water mist spraying is used for cooling. The temperature of the extrusion die is 450 °C, and the extrusion speed is 140 mm / minute. Subsequently, the aluminum alloy profile cooled to room temperature in the extrusion state is subjected to a cold bending and straightening process by a robotic arm and then sawed into small sections. Finally, the extruded new aluminum alloy is subjected to a heat treatment process of solution treatment + artificial aging in a high-temperature furnace and a low-temperature furnace. The solution treatment process is a high-temperature short-time solution method of holding at 550 °C for 1 hour, and the aging process is an artificial aging treatment method of holding at 150 °C for 10 hours. Artificial aging treatment is carried out quickly 1 hour after solution treatment.

[0137] Example 5

[0138] Taking the Al-Mg-Si series aluminum alloy as an example, the new high-strength and high-toughness aluminum alloy of the present application is manufactured, numbered JNL-5. The specific steps are as follows:

[0139] In the first step, the above-mentioned Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc, and pure magnesium ingots with a mass percentage of 99.9% and pure aluminum ingots are calculated and selected according to the corresponding batching ratios.

[0140] In the second step, the corresponding solid-state ingredients are placed in a graphite crucible of a 10-ton aluminum alloy melting furnace, heated to 700 °C to melt the solid aluminum alloy, held at 710 °C and stirred with an iron stirring rod for 25 minutes, and then left to stand for 10 minutes after being stirred evenly; during this process, attention needs to be paid to the cleanliness inside and outside the melting furnace and stirring is carried out under a nitrogen atmosphere.

[0141] In the third step, a refining treatment after heating is carried out while holding at 710 °C to prevent the manufacturing defect of doped slag floating due to the low temperature of the aluminum liquid. The refining temperature is 737 °C, and the refining agent selected is hexachloroethane, and the addition ratio is 0.8%. The material is packaged in aluminum foil paper and stirred for 15 minutes. After refining, it is left to stand for 18 minutes, and pouring is completed when the temperature drops to 725 °C.

[0142] After the above process steps are completed, the chemical composition of the alloy is detected. The specific chemical composition (mass percentage) is as follows: 1.00% Si, 0.68% Mg, 0.73% Fe, 0.087% Cu, 0.19% Mn, 0.19% Sc.

[0143] Then, a single-stage homogenization treatment is carried out in a high-temperature furnace at 460 °C for 20 hours. After that, it is quickly cooled to room temperature by water cooling in a reservoir. The homogenized aluminum alloy ingot is heated to 455 °C, held for 1.5 hours, and the extrusion die is preheated. Subsequently, the hot extrusion process of the porthole die is completed by a horizontal extruder, and water mist spraying cooling is used. The temperature of the extrusion die is 450 °C, and the extrusion speed is 140 mm / min. Subsequently, the extruded aluminum alloy profile cooled to room temperature is subjected to a cold bending and straightening process by a robotic arm and then sawed into small segments. Finally, the extruded new aluminum alloy is subjected to a heat treatment process of solution treatment + artificial aging in a high-temperature furnace and a low-temperature furnace. The solution treatment process is a high-temperature short-time solution method at 550 °C for 2 hours, and the aging process is an artificial aging treatment method at 150 °C for 12 hours. The artificial aging treatment is carried out quickly 1 hour after the solution treatment.

[0144] Example 6

[0145] Taking the Al-Mg-Si series aluminum alloy as an example, the new high-strength and high-toughness aluminum alloy of the present application is manufactured, numbered JNL-6. The specific steps are as follows:

[0146] In the first step, the above-mentioned Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc, and pure magnesium ingots with a mass percentage of 99.9% and pure aluminum ingots with a mass percentage of 99.9% are calculated and selected according to the corresponding batching ratios.

[0147] In the second step, the corresponding solid-state ingredients are placed in a graphite crucible of a 10-ton aluminum alloy melting furnace and heated to 700 °C to melt the solid-state aluminum alloy. It is held at 710 °C and stirred with an iron stirring rod for 25 minutes. After stirring evenly, it is left standing for 10 minutes; during this process, attention needs to be paid to the cleanliness inside and outside the melting furnace and stirring is carried out under a nitrogen atmosphere.

[0148] In the third step, a refining treatment after heating is carried out while maintaining the temperature at 710 °C to prevent the manufacturing defect of doped slag caused by the low temperature of the aluminum liquid resulting in the floating of the slag. The refining temperature is 737 °C, and the refining agent selected is hexachloroethane, with an addition ratio of 0.8%. The material is packaged in aluminum foil paper and stirred for 15 minutes. After refining, it is left standing for 18 minutes, and pouring is completed when the temperature drops to 725 °C.

[0149] After the above process steps are completed, the chemical composition of the alloy is detected. The specific chemical composition (mass percentage) is as follows: 1.00% Si, 0.68% Mg, 0.73% Fe, 0.087% Cu, 0.19% Mn, 0.19% Sc.

[0150] Then, a single-stage homogenization treatment is carried out in a high-temperature furnace at 460 °C for 20 hours. After that, it is quickly cooled to room temperature through a water reservoir. The homogenized aluminum alloy ingot is heated to 455 °C, held for 1.5 hours, and the extrusion die is preheated. Subsequently, the hot extrusion process of the porthole die is completed through a horizontal extruder, and water mist spraying is used for cooling. The temperature of the extrusion die is 450 °C, and the extrusion rate is 140 mm / minute. Subsequently, the extruded aluminum alloy profile cooled to room temperature is subjected to a cold bending and straightening process by a robotic arm and then sawed into small segments. Finally, the extruded new aluminum alloy is subjected to a heat treatment process of solution treatment + artificial aging in a high-temperature furnace and a low-temperature furnace. The solution treatment process is a high-temperature short-time solution method of holding at 550 °C for 1 hour, and the aging process is an artificial aging treatment method of holding at 140 °C for 12 hours. Artificial aging treatment is carried out quickly 1 hour after solution treatment.

[0151] Example 7

[0152] Taking the Al-Mg-Si series aluminum alloy as an example, the new high-strength and high-toughness aluminum alloy of the present application is manufactured, numbered JNL-7. The specific steps are as follows:

[0153] First step, calculate and select the Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc, and pure magnesium ingots with a mass percentage of 99.9% and pure aluminum ingots with a mass percentage of 99.9% according to the corresponding batching ratios.

[0154] Second step, put the corresponding solid-state ingredients into a graphite crucible of a 10-ton aluminum alloy melting furnace, heat to 700 °C to melt the solid-state aluminum alloy, hold at 710 °C and stir it with an iron stirring rod for 25 minutes, and let it stand for 10 minutes after stirring evenly; during this process, attention needs to be paid to the cleanliness inside and outside the melting furnace and stirring under a nitrogen atmosphere.

[0155] Third step, carry out a refining treatment after heating up when holding at 710 °C to prevent the manufacturing defect of doped slag caused by the low temperature of the aluminum liquid resulting in the floating of the slag. The refining temperature is 737 °C, and the refining agent selected is hexachloroethane, and the addition ratio is 0.8%. The material is packaged in aluminum foil paper and stirred for 15 minutes. After refining, let it stand for 18 minutes and complete pouring when the temperature drops to 725 °C.

[0156] After the above process steps are completed, the chemical composition of the alloy is detected. The specific chemical composition (mass percentage) is as follows: 1.00% Si, 0.68% Mg, 0.73% Fe, 0.087% Cu, 0.19% Mn, 0.19% Sc.

[0157] Then, a single-stage homogenization treatment is carried out in a high-temperature furnace at 460 °C for 20 hours. After that, it is quickly cooled to room temperature through a water reservoir. The homogenized aluminum alloy ingot is heated to 455 °C, held for 1.5 hours, and the extrusion die is preheated. Subsequently, the hot extrusion process of the porthole die is completed through a horizontal extrusion press, and water mist spraying is used for cooling. The temperature of the extrusion die is 450 °C, and the extrusion speed is 140 mm / minute. Subsequently, the extruded aluminum alloy profile cooled to room temperature is subjected to a cold bending and straightening process by a robotic arm and then sawed into small segments. Finally, the extruded new aluminum alloy is subjected to a heat treatment process of solution treatment + artificial aging in a high-temperature furnace and a low-temperature furnace. The solution treatment process is a high-temperature short-time solution method of holding at 550 °C for 1 hour, and the aging process is an artificial aging treatment method of holding at 160 °C for 12 hours. Artificial aging treatment is carried out quickly 1 hour after solution treatment.

[0158] Example 8

[0159] Taking the Al-Mg-Si series aluminum alloy as an example, the new high-strength and high-toughness aluminum alloy of the present application is manufactured, numbered JNL-8. The specific steps are as follows:

[0160] In the first step, the above-mentioned Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc, and pure magnesium ingots with a mass percentage of 99.9% and pure aluminum ingots are calculated and selected according to the corresponding batching ratios.

[0161] In the second step, the corresponding solid-state ingredients are placed in a graphite crucible of a 10-ton aluminum alloy melting furnace and heated to 700 °C to melt the solid-state aluminum alloy. It is held at 710 °C and stirred with an iron stirring rod for 25 minutes. After stirring evenly, it is left standing for 10 minutes; during this process, attention needs to be paid to the cleanliness inside and outside the melting furnace and stirring is carried out under a nitrogen atmosphere.

[0162] In the third step, after the temperature is raised during the holding at 710 °C, a refining treatment is carried out to prevent the manufacturing defect of doped slag floating due to the low temperature of the aluminum liquid. The refining temperature is 737 °C, and the refining agent selected is hexachloroethane, with an addition ratio of 0.8%. The material is packaged in aluminum foil paper and stirred for 15 minutes. After refining, it is left standing for 18 minutes, and pouring is completed when the temperature drops to 725 °C.

[0163] After the above process steps are completed, the chemical composition of the alloy is detected. The specific chemical composition (mass percentage) is as follows: 1.00% Si, 0.68% Mg, 0.73% Fe, 0.087% Cu, 0.19% Mn, 0.19% Sc.

[0164] Then, a single-stage homogenization treatment is carried out in a high-temperature furnace at 460 °C for 20 hours. After that, it is quickly cooled to room temperature through a water reservoir. The homogenized aluminum alloy ingot is heated to 455 °C, held for 1.5 hours, and the extrusion die is preheated. Subsequently, the hot extrusion process of the porthole die is completed through a horizontal extrusion press, and water mist spraying is used for cooling. The temperature of the extrusion die is 450 °C, and the extrusion speed is 140 mm / minute. Subsequently, the extruded aluminum alloy profile cooled to room temperature is subjected to a cold bending and straightening process by a robotic arm and then sawed into small segments. Finally, the extruded new aluminum alloy is subjected to a heat treatment process of solution treatment + artificial aging in a high-temperature furnace and a low-temperature furnace. The solution treatment process is a high-temperature short-time solution method of holding at 550 °C for 1 hour, and the aging process is an artificial aging treatment method of holding at 175 °C for 12 hours. Artificial aging treatment is carried out quickly 1 hour after solution treatment.

[0165] Example 9

[0166] Taking the Al-Mg-Si series aluminum alloy as an example, the new high-strength and high-toughness aluminum alloy of the present application is manufactured, numbered JNL-9. The specific steps are as follows:

[0167] In the first step, the above-mentioned Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc, and pure magnesium ingots with a mass percentage of 99.9% and pure aluminum ingots with a mass percentage of 99.9% are calculated and selected according to the corresponding batching ratios.

[0168] In the second step, the corresponding solid-state ingredients are placed in a graphite crucible of a 10-ton aluminum alloy melting furnace and heated to 700 °C to melt the solid-state aluminum alloy. It is held at 710 °C and stirred with an iron stirring rod for 25 minutes. After stirring evenly, it is left standing for 10 minutes; during this process, attention needs to be paid to the cleanliness inside and outside the melting furnace and stirring is carried out under a nitrogen atmosphere.

[0169] In the third step, a refining treatment after temperature rise is carried out while holding at 710 °C to prevent the manufacturing defect of doped slag floating due to the low temperature of the aluminum liquid. The refining temperature is 737 °C, and the refining agent selected is hexachloroethane, with an addition ratio of 0.8%. The material is packaged in aluminum foil paper and stirred for 15 minutes. After refining, it is left standing for 18 minutes, and pouring is completed when the temperature drops to 725 °C.

[0170] After the above process steps are completed, the chemical composition of the alloy is detected. The specific chemical composition (mass percentage) is as follows: 1.00% Si, 0.68% Mg, 0.73% Fe, 0.087% Cu, 0.19% Mn, 0.19% Sc.

[0171] Then, a single-stage homogenization treatment is carried out in a high-temperature furnace at 460 °C for 20 hours. After that, it is quickly cooled to room temperature through a water reservoir. The homogenized aluminum alloy ingot is heated to 455 °C, held for 1.5 hours, and the extrusion die is preheated. Subsequently, the hot extrusion process of the porthole die is completed through a horizontal extrusion machine, and water mist spraying is used for cooling. The temperature of the extrusion die is 450 °C, and the extrusion speed is 140 mm / minute. Subsequently, the extruded aluminum alloy profile cooled to room temperature is subjected to a cold bending and straightening process by a robotic arm and then sawed into small segments. Finally, the extruded new aluminum alloy is subjected to a heat treatment process of solution treatment + artificial aging in a high-temperature furnace and a low-temperature furnace. The solution treatment process is a high-temperature short-time solution method of holding at 560 °C for 1 hour, and the aging process is an artificial aging treatment method of holding at 150 °C for 12 hours. Artificial aging treatment is carried out quickly 1 hour after solution treatment.

[0172] Comparative Example 1

[0173] Taking the Al-Mg-Si series aluminum alloy as an example, the new high-strength and high-toughness aluminum alloy of the present application is manufactured, numbered JNL-C1. The specific steps are as follows:

[0174] First step, calculate and select the Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc, and pure magnesium ingots with a mass percentage of 99.9% and pure aluminum ingots with a mass percentage of 99.9% according to the corresponding batching ratios.

[0175] Second step, put the corresponding solid ingredients into a graphite crucible of a 10-ton aluminum alloy melting furnace, heat to 700 °C to melt the solid aluminum alloy, hold at 710 °C and stir it with an iron stirring rod for 25 minutes, and let it stand for 10 minutes after stirring evenly; during this process, attention needs to be paid to the cleanliness inside and outside the melting furnace and stirring under a nitrogen atmosphere.

[0176] Third step, carry out a refining treatment after heating up while holding at 710 °C to prevent the manufacturing defect of doped slag caused by the low temperature of the aluminum liquid resulting in the floating of the slag. The refining temperature is 737 °C, the refining agent selected is hexachloroethane, and the addition ratio is 0.8%. The material is packaged in sub-packages with aluminum foil paper and stirred for 15 minutes. After refining, let it stand for 18 minutes, and complete pouring when the temperature drops to 725 °C.

[0177] After the above process steps are completed, the chemical composition of the alloy is detected. The specific chemical composition (mass percentage) is as follows: 1.00% Si, 0.68% Mg, 0.73% Fe, 0.087% Cu, 0.19% Mn, 0.19% Sc.

[0178] Next, a single-stage homogenization treatment is carried out in a high-temperature furnace at 460 °C for 20 hours. Then it is quickly cooled to room temperature through a water reservoir. The homogenized aluminum alloy ingot is heated to 455 °C and held for 1.5 hours. The extrusion die is preheated, and then the hot extrusion process of the porthole die is completed through a horizontal extruder, and water mist spraying cooling is used. The temperature of the extrusion die is 450 °C, and the extrusion rate is 140 mm / minute. Subsequently, the extruded aluminum alloy profile cooled to room temperature is subjected to a cold bending and straightening process by a robotic arm and then sawed into small segments. Finally, the extruded new aluminum alloy is subjected to an aging heat treatment process (without solution treatment) in a low-temperature furnace. The artificial aging process is to hold at 150 °C for 12 hours

[0179] Comparative Example 2

[0180] Taking the Al-Mg-Si series aluminum alloy as an example, the new high-strength and tough aluminum alloy of the present application is manufactured, numbered JNL-C2. The specific steps are as follows:

[0181] In the first step, the Al-50Si, Al-50Cu, Al-30Mn, Al-2Sc, and pure magnesium ingots with a mass percentage of 99.9% and pure aluminum ingots with a mass percentage of 99.9% are calculated and selected according to the corresponding batching ratios.

[0182] In the second step, the corresponding solid-state ingredients are put into a graphite crucible of a 10-ton aluminum alloy melting furnace and heated to 700 °C to melt the solid-state aluminum alloy. It is held at 710 °C and stirred with an iron stirring rod for 25 minutes. After stirring evenly, it is left standing for 10 minutes; during this process, attention needs to be paid to the cleanliness inside and outside the melting furnace and stirring is carried out under a nitrogen atmosphere.

[0183] In the third step, a refining treatment after temperature rise is carried out while holding at 710 °C to prevent the manufacturing defect of doped slag caused by the low temperature of the aluminum liquid resulting in the floating of the slag. The refining temperature is 737 °C, and the refining agent selected is hexachloroethane, and the addition ratio is 0.8%. The material is packaged in sub-packages with aluminum foil paper and stirred for 15 minutes. After refining, it is left standing for 18 minutes, and pouring is completed when the temperature drops to 725 °C.

[0184] After the above process steps are completed, the chemical composition of the alloy is detected. The specific chemical composition (mass percentage) is as follows: 1.00% Si, 0.68% Mg, 0.73% Fe, 0.087% Cu, 0.19% Mn, 0.19% Sc.

[0185] Next, a single-stage homogenization treatment is carried out in a high-temperature furnace at 460 °C for 20 hours. Then, it is quickly cooled to room temperature through a reservoir of water. The homogenized aluminum alloy ingot is heated to 455 °C and held for 1.5 hours. The extrusion die is preheated, and then the hot extrusion process of the porthole die is completed through a horizontal extrusion press, with water mist spraying for cooling. The temperature of the extrusion die is 450 °C, and the extrusion rate is 140 mm / min. Subsequently, the extruded aluminum alloy profile cooled to room temperature is subjected to a cold bending and straightening process by a robotic arm and then sawed into small segments. Finally, the extruded new aluminum alloy is subjected to a solution heat treatment process (without aging treatment) in a high-temperature furnace. The solution treatment process is to hold at 550 °C for 1 hour.

[0186] II. Performance Evaluation

[0187] (1) Yield strength, tensile strength, elongation

[0188] Tensile specimens are machined according to the requirements of GB / T 228.1-2010. According to the metal material tensile test method of GB / T 288.1-2010, experiments are carried out on a Zwick / Roell Z020 universal mechanical testing machine. The tensile speed is set at 0.5 mm / min, and the yield strength, tensile strength, and elongation data are obtained from the instrument.

[0189] (2) Measurement of aluminum alloy grain size and Al3Sc precipitate phase radius

[0190] An X-ray diffraction analyzer (XRD), purchased from Rigaku in Japan with the model of RigakuuUltima IV, is used. The set parameters are: the angular range is 10 - 120°, the scanning speed is 10° / min, and the scanning step size is 0.02°. The results are calculated by fitting the peak shape using the Scherrer equation.

[0191] The specific calculation method is as follows:

[0192] D hkl = Nd hkl = (0.89λ) / (β hkl cosθ)

[0193] Where D hkl is the aluminum alloy grain size perpendicular to the diffraction direction. λ is the wavelength of the incident X-ray; θ is the Bragg diffraction angle; β hkl is the full width at half maximum of the diffraction plane. Where d hkl is the interplanar spacing perpendicular to the (hkl) crystal plane, and N is the number of unit cells included in this direction.

[0194] The radius of the Al3Sc precipitation phase was measured under the microstructure by using Gatan Digital Micrograph software.

[0195] The test results are shown in Table 1 below.

[0196] Table 1 Grain sizes and mechanical properties of each example and comparative example

[0197]

[0198] Figure 5 are the mechanical property curves of various aluminum alloy profiles after split die extrusion heat treatment according to the embodiments of the present application. The detailed results of each performance parameter are shown in Table 1 above. As Figure 5 shown, through solution treatment at 550 °C / 1 h + aging at 150 °C / 12 h, the mechanical properties of the Al-Mg-Sc alloy are significantly increased. Among them, the average transverse and longitudinal tensile strengths and yield strengths of the JNL-2 alloy are slightly lower than those of the JNL-1. Since the Sc contents of the JNL-1 and JNL-2 are different, the eutectic points of the precipitated phases change, and the solution strengthening effect is obvious, making the strength of the JNL-1 slightly higher, but the toughness (elongation) slightly lower. The yield strength of the JNL-3 alloy is higher than those of the JNL-1 and JNL-2, the average transverse and longitudinal tensile strengths are close to those of the JNL-2 and slightly lower than those of the JNL-1, and the elongation is higher than that of the JNL-1 and close to that of the JNL-2, and its grain refinement is obvious. This shows that in terms of strength, the Sc content is optimal at 0.14% - 0.20%. The closer it is to 0.3%, the more the Al matrix and Sc will segregate at the grain boundaries, forming coarse second phases, thus unable to achieve grain refinement and affecting the strength of the aluminum alloy.

[0199] JNL4 - JNL9 are aluminum alloys under different solution + aging heat treatment conditions. Since solute atoms form solid solutions after dissolving into the aluminum matrix during solution treatment, the lattice parameters of the solute atoms are different from those of the matrix atoms, resulting in lattice distortion. The generation of the distortion hinders the movement of dislocations, and the strength and hardness of the alloy are thus improved. Therefore, the mechanical properties of the JNL4 - JNL9 alloys are higher than those of the aluminum alloy in the initial extrusion state. However, as the solution temperature in the JNL-9 increases to 560 °C, the size and spacing of the precipitated phases at the grain boundaries change significantly, the precipitation band becomes narrower, the grains become coarser, and the pinning effect on dislocations decreases, resulting in the mechanical properties of the JNL-9 being lower than those of the JNL-4. When the solution temperature is 550 °C and the solution time increases to 2 hours, the precipitated phases that have already been dispersed and refined in the grains cannot be further refined. Moreover, the impurity phases will also become crack sources, further affecting the strength of the alloy. Since the temperature has a greater impact on solution treatment, the mechanical properties of the JNL-5 are better than those of the JNL-9.

[0200] The aging treatment process is classified according to the aging temperature, and there are three cases: under-aging, peak aging, and over-aging. Due to the abnormally large size and significant reduction in the number of intragranular precipitates, the aging temperature in JNL-7 and JNL-8 is over-aging treatment, resulting in lower tensile strength and yield strength of the two compared to the JNL-3 alloy. After holding at 150 °C for 12 hours, a large number of dislocations are introduced inside the alloy, which can act as nucleation sites and facilitate the generation of precipitation phases. Therefore, the tensile strength of the peak-aged specimens JNL-3 and JNL-4 has been improved. However, due to the shorter aging time of JNL-4, its mechanical properties have not reached the optimum and are lower than those of the JNL-3 alloy. When the aging temperature is 140 °C, under-aging occurs. Under the same treatment time, the strengthening effect of under-aging is weaker than that of peak aging. Therefore, the performance of JNL-6 is lower than that of JNL-3 and JNL-4. However, JNL-6 still has the effect of dislocation strengthening, and its performance is higher than that of JNL-7 and JNL-8.

[0201] After the treatment of aging at 150 °C for 12 hours, the performance of JNL-C1 is improved compared with the initial extruded state. This is because the internal stress caused by the second phase in the matrix and the chemical effect caused when dislocations pass through them hinder the movement of dislocations. The precipitation of the Al3Sc phase improves the alloy strength and causes a significant age hardening effect. However, compared with the JNL-1, JNL-2, and JNL-3 alloys, both the strength and plasticity are reduced. This is because after severe deformation, aging treatment is directly carried out. Many phases have not dissolved into the matrix, and the second phase precipitates preferentially. After the maximum density of matrix precipitation, semi-coherent dispersed phases precipitate in the alloy grains, and coarser continuous chain-like particles are distributed at the grain boundaries, resulting in a significant reduction in both strength and plasticity.

[0202] After high-temperature short-time solution treatment at 550 °C for 1 hour, the mechanical properties of JNL-C2 are improved. This is because there are many undissolved phases after hot extrusion, and their distribution is uneven. The undissolved phase particles will become stress concentration and crack initiation sites. It is necessary to make the phase morphology irregular, denser, smaller in size, and more dispersed through high-temperature short-time single-stage solution treatment. Although the re-solution effect of the second phase is good at this time, there are still a small number of coarse phases, and the comprehensive mechanical properties such as strength and plasticity are significantly lower than those of the JNL-1, JNL-2, and JNL-3 alloys.

[0203] Figure 6 It is the SEM (scanning electron microscope) microstructural image of the JNL-3 alloy after heat treatment obtained according to Example 3 of the present application. As Figure 6As shown, after extrusion deformation, the grains of JNL-3 aluminum alloy are flattened and elongated along the extrusion axis direction, and the grains are distributed in a streamline fiber structure. After hot extrusion deformation, the relatively large black massive impurity particles in the original structure before extrusion are violently extruded and broken into blocks, and are continuously distributed along the local strip-shaped grain boundaries. The grain size is 44.8μm.

[0204] In summary, through the aluminum alloy preparation process of the present application, the mechanical properties, grain refinement, and strengthening effect of the precipitation phase are optimized in each embodiment, and the mechanical properties of the aluminum alloy are improved.

[0205] It should be noted that the present application is not limited to the above embodiments. The above embodiments are only examples, and embodiments with the same structure and the same effect as the technical idea within the technical solution scope of the present application are included in the technical scope of the present application. In addition, within the scope of not departing from the gist of the present application, various deformations that can be thought of by those skilled in the art are applied to the embodiments, and other ways constructed by combining some constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. An aluminum alloy profile, characterized in that, By mass percentage, the aluminum alloy profile comprises the following components: 0.6 - 1.3% Si, 0.6 - 1.0% Mg, 0.6 - 0.73% Fe, 0.05 - 0.2% Cu, 0.1 - 0.2% Mn, and 0.14 - 0.20% Sc, with the balance being Al and impurities, where the mass of a single impurity ≤ 0.02% and the total mass of impurities ≤ 0.1%; The aluminum alloy grains are distributed in a streamline fiber structure, and the size of the aluminum alloy grains is 34.9 μm - 54 μm; The aluminum alloy matrix contains uniformly distributed Al3Sc precipitate phases, and the Al3Sc precipitate phases are coherent with the aluminum alloy matrix, and the radius of the Al3Sc precipitate phases remains at 4 - 10 nm.

2. A manufacturing method of an aluminum alloy profile, characterized in that, It includes: (1) Charge intermediate alloys Al - 50Si, Al - 50Cu, Al - 30Mn, Al - 2Sc, 99.9 mass% pure magnesium ingots, and 99.9 mass% pure aluminum ingots to obtain a solid charge; (2) Heat the solid charge obtained in step (1) so that the solid charge melts and is kept warm, stirred evenly, and then left standing to obtain a molten charge; (3) Perform refining treatment on the molten charge obtained in step (2), where the molten charge is sub - packaged and stirred, left standing after refining treatment, and casting is completed after the temperature drops to meet the requirements of the mirror sample to obtain an aluminum alloy ingot; (4) Perform single - stage homogenization treatment on the aluminum alloy ingot obtained in step (3), and then quickly cool it to room temperature to obtain a homogenized aluminum alloy ingot; (5) Heat and keep warm the homogenized aluminum alloy ingot obtained in step (4), preheat the extrusion die, and then carry out the hot extrusion process of a one - die two - hole split die, with an extrusion rate of 120 - 140 mm / minute, and then cool it to room temperature; (6) Perform a cold bending and straightening process on the extruded aluminum alloy profile cooled to room temperature obtained in step (5), and: (7) Perform heat treatment of solution treatment and artificial aging on the aluminum alloy profile obtained in step (6). The temperature of the solution treatment is 550 - 560 °C, and the holding time is 1 - 2 hours; the temperature of the artificial aging is 140 - 175 °C, and the holding time is 10 - 12 hours. The interval time between the solution treatment and the artificial aging does not exceed 2 hours to obtain the aluminum alloy profile; Among them, by mass percentage, the aluminum alloy profile comprises the following components: 0.6 - 1.3% Si, 0.6 - 1.0% Mg, 0.6 - 0.73% Fe, 0.05 - 0.2% Cu, 0.1 - 0.2% Mn, and 0.14 - 0.20% Sc, with the balance being Al and impurities, where the mass of a single impurity ≤ 0.02% and the total mass of impurities ≤ 0.1%; The aluminum alloy grains are distributed in a streamline fiber structure, and the size of the aluminum alloy grains is 34.9 μm - 54 μm; The aluminum alloy matrix contains uniformly distributed Al3Sc precipitate phases, and the Al3Sc precipitate phases are coherent with the aluminum alloy matrix.

3. The method according to claim 2, characterized in that, In step (3), the stirring time is 10 - 15 minutes; the temperature of the refining treatment is 730 - 740 °C; the standing time is 15 - 20 minutes; pouring is completed when the temperature drops to 720 - 730 °C.

4. The method according to claim 2, characterized in that, In step (4), single-stage homogenization treatment is carried out in a high-temperature furnace; wherein, the holding temperature is 460 °C - 470 °C, and the holding time is 20 - 24 hours.

5. A battery pack box body, characterized in that, Manufactured from the aluminum alloy profile according to claim 1 or the aluminum alloy profile prepared by the method according to claim 2.

6. A battery pack, characterized in that, Including the battery pack box according to claim 5.

7. An electrical device, characterized in that, Including the battery pack according to claim 6, and the battery pack is used as the power source or the energy storage unit of the electrical device.

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