High-toughness anti-impact aluminum alloy profile for automobile battery pack and preparation method thereof

Abstract

This invention relates to the field of aluminum alloy materials, specifically to a high-toughness, impact-resistant aluminum alloy profile for automotive battery packs and its preparation method. The components and their weight percentages in this high-toughness, impact-resistant aluminum alloy profile for automotive battery packs are as follows: Si content 0.65-0.70%; Fe content <0.20%; Cu content 0.11-0.16%; Mn content 0.19-0.24%; Mg content 0.55-0.60%; Cr content 0.15-0.20%; Zn content <0.10%; Ti content... The content of Mn is 0.02-0.05%; the Er content is 0.13-0.20%; the Zr content is 0.10-0.15%; the Mn / Cr ratio is ≥1.2, 1.6 ≥ Er / Zr ≥1.3; and the balance is Al. This automotive battery pack uses high-toughness, impact-resistant aluminum alloy profiles with good formability, high toughness, impact resistance without cracking, and corrosion resistance. This improves the protective performance of the battery pack housing, reduces the reliance on other protective materials in the battery pack protective structure design, and effectively reduces weight, which is more in line with the requirements for lightweighting and safety in the development of new energy vehicles.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy materials, specifically to a high-toughness, impact-resistant aluminum alloy profile for automotive battery packs and its preparation method. Background Technology

[0002] For collision safety of new energy vehicles, the most important factor is the protection of the battery pack. The battery pack may be subjected to frontal collisions, side collisions, and bottom scraping. In the vehicle body design, the protection of the battery pack at the front and sides is generally enhanced by structural designs such as strengthening the longitudinal beams and door sill beams and adding front protective crossbeams.

[0003] The mandatory standard GB 38031-2025, "Safety Requirements for Power Batteries for Electric Vehicles," recently drafted by the Ministry of Industry and Information Technology, has entered the approval process and will be implemented on July 1, 2026. The new standard adds a bottom impact test to the battery pack performance testing. Traditional designs for bottom impact protection of battery packs do not have special requirements beyond the mechanical properties of the battery pack material itself. Generally, an additional bottom protection structure, such as a protective plate connected to the battery pack's bottom plate and coated with protective paint, is added to enhance the battery pack's protection performance under drag and scrape conditions, thus passing the vehicle drag test. Battery pack bodies are generally welded from aluminum alloy profiles. Without other bottom protection structures, aluminum alloy battery pack bodies generally cannot pass the drag test alone. The bottom plate of the battery pack body will crack or break after impact, damaging the battery.

[0004] The aluminum alloy battery pack casing is composed of aluminum profiles with different cross-sectional structures. The frame and base plate profiles are required to be consistent. Currently, the mainstream alloy is 6061 alloy. Conventional aluminum alloy battery pack casings are made of 6061 alloy. However, it has poor formability, severe quenching deformation, and low toughness. After impact, the surface of the profile is easily damaged and cracked, and it cannot pass the impact test without external structural protection. In terms of mechanical properties, only room temperature mechanical properties are required: yield strength ≥240Mpa, tensile strength ≥260Mpa, and elongation after fracture ≥7%. There are no standard requirements for the toughness and impact resistance of the profile. It is not affected by the requirements of the whole vehicle bottoming test. The profile can meet the requirements by using the 6061 national standard composition and general production process.

[0005] According to the upcoming GB 38031-2025 standard for safety requirements of power batteries for electric vehicles, the bottom impact test requires a 30mm diameter impact head to impact the bottom of an unprotected aluminum alloy battery pack with 150J of energy. The condition of the bottom plate profile of the battery pack is then observed after the impact. Bottom plate profiles made of 6061 and other existing aluminum alloys using conventional processes meet the mechanical properties requirements. In terms of bending performance, the bending angle generally does not exceed 80°. The impact test results in varying degrees of through cracks, fragmentation, or even substrate detachment on the surface of the profile. The impact-facing surface protrudes significantly, and in severe cases, the impact penetrates the cavity, causing through cracks on the impact-facing surface of the profile. The performance of existing alloy profiles cannot effectively guarantee battery safety.

[0006] In summary, there is an urgent need to solve the technical problem that existing technologies cannot simultaneously provide aluminum alloy profiles for automotive battery packs with both high toughness and impact resistance. Summary of the Invention

[0007] The present invention aims to solve the technical problem of how to provide an aluminum alloy profile for automotive battery packs that combines high toughness and impact resistance.

[0008] To achieve the above objectives, a first aspect of the present invention provides a high-toughness, impact-resistant aluminum alloy profile for automotive battery packs, wherein the components and their weight percentages in the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs are as follows:

[0009] Si content 0.65-0.70%;

[0010] Fe content < 0.20%;

[0011] The Cu content is 0.11-0.16%;

[0012] The Mn content is 0.19-0.24%;

[0013] The Mg content is 0.55-0.60%;

[0014] The Cr content is 0.15-0.20%;

[0015] Zn content < 0.10%;

[0016] The Ti content is 0.02-0.05%;

[0017] Er content is 0.13-0.20%;

[0018] The Zr content is 0.10-0.15%;

[0019] Mn / Cr≥1.2, 1.6≥Er / Zr≥1.3;

[0020] The content of a single impurity is ≤0.05%;

[0021] The total content of other impurity elements is ≤0.15%;

[0022] The margin is Al.

[0023] A second aspect of the present invention provides a method for preparing the above-mentioned high-toughness impact-resistant aluminum alloy profile for automotive battery packs, wherein the preparation method includes melting, casting, homogenization, extrusion, cooling, and aging.

[0024] The cooling conditions include: the extruded profile passes through a water spraying area, and water is sprayed onto the upper and lower surfaces of the extruded profile for gradient cooling.

[0025] The conditions for gradient cooling include: a water flow rate of 0.6-0.9 m³ / s for the first 25% of the spray zone. 3 The cooling rate is 5-10℃ / s, which cools the extruded profile to 450℃. Then, in the 25-75% section of the water spraying area, the water flow rate is 5-7m³ / h. 3 The cooling rate is 20-40℃ / s, which cools the extruded profile to 150℃. Finally, in the last 25% of the water spraying area, the water flow rate is 2-3m³ / h. 3 The cooling rate is 100-150℃ / s / h, which cools the extruded profile to 20-30℃.

[0026] The beneficial effects of this invention are as follows:

[0027] This invention, through component modification and simultaneous optimization of heat treatment, production processes, and profile structure, provides a high-toughness, impact-resistant profile for aluminum alloy battery packs. It possesses excellent formability, high toughness, and impact resistance without cracking. The product's mechanical properties reach Rm≥260MPa; RP0.2≥290MPa; A50mm≥16%; and a bending angle of 130°. After being impacted by a 30mm diameter head with 150J of energy, the profile showed no surface cracks. Similarly, after being impacted by a 25mm diameter head with 150J of energy, the surface remained crack-free. The product's superior toughness and impact resistance improve the protective performance of the battery pack housing, reduce reliance on other protective materials in the battery pack's protective structure design, and effectively reduce weight, better meeting the requirements for lightweighting and safe operation in the development of new energy vehicles. Attached Figure Description

[0028] Figure 1 This is a high-magnification metallographic image of the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs provided in Embodiment 1 of the present invention.

[0029] Figure 2This is a test diagram of the intergranular corrosion susceptibility of the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs provided in Embodiment 1 of the present invention.

[0030] Figure 3 This is an impact test result diagram of the high-toughness impact-resistant aluminum alloy profile for automotive battery packs provided in Embodiment 1 of the present invention;

[0031] Figure 4 This is a high-magnification metallographic image of the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs provided in Embodiment 2 of the present invention.

[0032] Figure 5 This is a test diagram of the intergranular corrosion susceptibility of the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs provided in Embodiment 2 of the present invention.

[0033] Figure 6 The image shows the impact test results of the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs provided in Embodiment 2 of the present invention. Detailed Implementation

[0034] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0035] In the existing technology, the conventional aluminum alloy battery pack casing is made of 6061 alloy, which has poor formability, requires a lot of quenching deformation, has low toughness, and the surface of the profile is easily damaged and cracked after impact, making it impossible to pass the impact test without external structural protection.

[0036] In this invention, the inventors discovered that by using a specific alloy ratio, along with a specific extrusion cooling process and a specific profile structure, it is possible to produce a high-toughness, impact-resistant aluminum alloy profile for automotive battery packs that combines high toughness and impact resistance.

[0037] Therefore, the first aspect of the present invention provides a high-toughness, impact-resistant aluminum alloy profile for automotive battery packs, wherein the components and their weight percentages in the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs are as follows:

[0038] Si content 0.65-0.70%;

[0039] Fe content < 0.20%;

[0040] The Cu content is 0.11-0.16%;

[0041] The Mn content is 0.19-0.24%;

[0042] The Mg content is 0.55-0.60%;

[0043] The Cr content is 0.15-0.20%;

[0044] Zn content < 0.10%;

[0045] The Ti content is 0.02-0.05%;

[0046] Er content is 0.13-0.20%;

[0047] The Zr content is 0.10-0.15%;

[0048] Mn / Cr ≥ 1.2, 1.6 ≥ Er / Zr ≥ 1.3; single impurity content ≤ 0.05%;

[0049] The total content of other impurity elements is ≤0.15%;

[0050] The margin is Al.

[0051] In this invention, the addition of specific amounts of Er and Zr causes the formation of intermetallic compound precipitates of Al3Zr and Al3Er within an aluminum matrix. These precipitates possess an L12 ordered crystal structure, are coherent with the aluminum matrix, have extremely low interfacial energy, and are highly stable. These fine, stable, and dispersed particles effectively pinnate grain boundaries and dislocations. Even at high temperatures, they can prevent grain boundary migration, exhibiting a strong ability to inhibit recrystallization and refine grain size. When added simultaneously, the Er to Zr ratio is controlled because Zr diffuses slowly in Al while Er diffuses quickly. Er and Zr do not independently form Al3Er and Al3Zr, but rather together form a core-shell composite precipitate. The core is the more stable Al3Zr, and the shell is Al3(Er, Zr). The specific Er-to-Zr ratio of this invention ensures that during precipitation, there are sufficient rapidly diffusing Er atoms to fully encapsulate each stable but difficult-to-nucleate Al3Zr core, thereby maximizing the formation of this perfect core-shell structure and exhibiting a synergistic effect. The specific Mn-Cr ratio of this invention also allows Mn and Cr to form dispersed phases such as Al6Mn and Al7Cr, inhibiting recrystallization. Excessively high Cr content can easily lead to the formation of coarse primary Cr-containing phases during solidification, severely impairing toughness. Maintaining the dominant position of Mn can suppress these harmful primary phases, ensuring sufficient Al6Mn phase to rapidly and effectively inhibit substructure recovery in the medium- and low-temperature range. Simultaneously, the addition of an appropriate amount of Cr phase stably extends the inhibitory effect to higher temperatures, forming a seamless coverage of the inhibitory effect. The addition of Er and Zr can significantly increase the recrystallization inhibition temperature. The synergistic effect of specific amounts of Mn, Cr, Er, and Zr can maintain a non-recrystallized subcrystalline structure even at the specific solution treatment temperature of this invention, thereby greatly improving material properties. The Mg content ensures that the maximum amount of β-carotene precipitates during the aging process. ” The Mg2Si strengthening phase is beneficial for obtaining stable and excellent strength. Controlling the Fe content at a low level of 0.20% and combining it with a specific range of Mn content can effectively reduce the formation of lamellar or needle-like β-AlFeSi phases, promoting their transformation into the smoother α-Al(FeMn)Si phase, which can significantly improve the plasticity, toughness and extrusion surface quality of the alloy.

[0052] According to the present invention, the high-toughness, impact-resistant aluminum alloy profile for the automotive battery pack has a vertical rib structure;

[0053] The automotive battery pack uses a high-toughness, impact-resistant aluminum alloy profile with 9-14 holes in a flat cavity. The openings of the flat cavity are on the left and right sides of the profile. The length of the flat cavity is 20-24 mm, the height of the flat cavity is 5 mm, the inner corner radius of the flat cavity is R2.0-R2.5 mm, and the outer corner radius is R1.0 mm.

[0054] In this invention, while ensuring the lightweight of the profile, the overall rigidity and impact resistance are improved through a multi-cavity + vertical rib structure. When the impact test completely hits the weak point of the profile (i.e. the center of the cavity), the cavity design size can most effectively resist the impact energy. Increasing the inner cavity radius (R2.0-2.5mm) can disperse the stress concentration during the impact and improve the impact resistance of the profile.

[0055] A second aspect of the present invention provides a method for preparing the above-mentioned high-toughness impact-resistant aluminum alloy profile for automotive battery packs, wherein the preparation method includes melting, casting, homogenization, extrusion, cooling, and aging;

[0056] The cooling conditions include: the extruded profile passes through a water spraying area, and water is sprayed onto the upper and lower surfaces of the extruded profile for gradient cooling.

[0057] The conditions for gradient cooling include: a water flow rate of 0.6-0.9 m³ / s for the first 25% of the spray zone. 3 The cooling rate is 5-10℃ / s, which cools the extruded profile to 450℃. Then, in the 25-75% section of the water spraying area, the water flow rate is 5-7m³ / h. 3 The cooling rate is 20-40℃ / s, which cools the extruded profile to 150℃. Finally, in the last 25% of the water spraying area, the water flow rate is 2-3m³ / h. 3 The cooling rate is 100-150℃ / s / h, which cools the extruded profile to 20-30℃.

[0058] The first 25% of the water spray area represents the front section of the water spray area, accounting for 25% of the total length of the water spray area. The 25-75% section represents the middle section of the water spray area, accounting for 50% of the total length of the water spray area. The last 25% section represents the rear section of the water spray area, accounting for 25% of the total length of the water spray area.

[0059] In this invention, a specific cooling process precisely controls the upper and lower water sprays, employing progressive and uniform cooling to reduce stress concentration in the profile and prevent cooling deformation. The first 25% of the water-sprayed area serves as initial shaping. Above 450℃, the alloy has low yield strength and good plasticity, but is extremely sensitive to thermal stress. A cooling rate of 5-10℃ / s allows heat to be fully conducted from the core to the surface, controlling the cross-sectional temperature difference to be less than 30℃. As the temperature difference decreases, the thermal stress caused by the temperature difference is controlled below the material's high-temperature yield strength, thereby preventing plastic deformation and macroscopic warping. This allows the profile temperature to drop uniformly to around 450℃, eliminating the initial temperature difference and avoiding the generation of huge tensile stress from rapid surface cooling. This partially restores the profile's strength to withstand subsequent strong cooling. The 25-75% portion of the water spray area allows the profile to rapidly pass through the equilibrium phase precipitation nose temperature range (450-300℃) at a cooling rate of 20-40℃ / s, quickly cooling it to below 150℃ to obtain a sufficiently supersaturated solid solution, generating high-density dislocations and subgrain boundaries, promoting the uniform nucleation of subsequent aging precipitates. The remaining 25% of the water spray area allows the profile to cool to room temperature.

[0060] According to the present invention, if the temperature difference in heat dissipation of the profile passing through the first 25% of the water spray area exceeds 30°C, the water flow rate should be reduced to 0.5-0.6 m³ / s. 3 / h.

[0061] In this invention, the amount of water is reduced to control the thermal stress caused by temperature difference, thereby preventing plastic deformation and macroscopic warping.

[0062] The heat dissipation difference is defined as the significant differences in cooling rate, temperature drop, and heat dissipation rate at different locations of the profile cross-section (such as corners, wall thickness center, ribs, surface and core, thin-walled and thick-walled areas) during the quenching process of aluminum extruded profiles, under the same quenching time and the same cooling medium environment, due to differences in cross-sectional shape, wall thickness distribution, heat conduction path, and cooling medium contact state. This difference is referred to as the heat dissipation difference at different locations of the cross-section.

[0063] In this invention, 25-75% of the water spray area is used to compensate for the heat dissipation differences in different parts of the profile, striving to achieve synchronous cooling of the entire cross section, control cooling deformation, and slowly release thermal stress.

[0064] According to the present invention, the homogenization conditions include: a homogenization regime of (377-383)℃×(6-7)h+(562-568)℃×(6-8)h.

[0065] In this invention, the first stage of a specific homogenization process, involving prolonged low-temperature holding, slowly activates atomic diffusion, dissolving some low-melting-point segregated elements at grain boundaries. Simultaneously, it provides a mild environment for the phase transformation of elements such as Mn and Cr. During this holding stage, Er, Zr, and Al are induced to form a more stable Al3Zr core with an Al3(Er, Zr) nanoscale composite phase as the outer shell. This also promotes the formation of fine, dispersed Mn and Cr particles. These early-precipitated microparticles act as pinning dislocations and subgrain boundaries. The subsequent second stage, at high temperature, ensures the thermal stability of these dispersed phases and further promotes their uniform distribution, suppressing grain coarsening. The high-temperature holding, close to the alloy's solidus line, efficiently dissolves the remaining coarse second phase, such as promoting the formation of long, needle-like... Phase-oriented granular α-Al 15 The (FeMn)3Si2 phase transformation improves the toughness of the material.

[0066] According to the present invention, the extrusion conditions include: a die temperature of 480-500°C, an extrusion ingot temperature of 500-520°C, a profile exit temperature of 510-550°C, and an extrusion speed of 2-3 m / min.

[0067] According to the present invention, the aging conditions include: an aging regime of (192-198)℃ × (12-14)h.

[0068] In this invention, the smelting and casting adopt conventional process parameters in the field, as long as they meet the requirements of subsequent processing.

[0069] According to the present invention, the smelting conditions include: a melting temperature of 710-760°C and a refining temperature of 730-750°C.

[0070] According to some preferred embodiments of the present invention, the melting temperature is 710-760℃, the refining temperature is 730-750℃, the refining agent dosage is 1.5 kg / TAl, the refining time is 25 min, the slag removal temperature is 730-735℃, the converter temperature is 750℃, the settling temperature is 720℃, the addition of scrap aluminum is not allowed, and the slag content of the ingot must meet the secondary requirements in GB / T32186-2015. Hydrogen element content is 0.15 ml / 100 g.

[0071] Test methods

[0072] Mechanical properties include: tensile strength Rp 0.2 Tensile strength R m The elongation after fracture was tested using an AG-X 100KN electronic universal testing machine, and the test method was in accordance with GB / T16865-2013 Tensile test specimens and methods for wrought aluminum, magnesium and their alloy processed products.

[0073] High-magnification microstructure testing equipment: AXIO universal research-grade inverted material microscope; testing standard: GB / T6892-2015 General industrial aluminum and aluminum alloy extruded profiles; testing method: GB / T3246.1-2012 Deformed aluminum and aluminum alloy products microstructure inspection method - Part 1: Microstructure inspection method.

[0074] The testing equipment for fusion joint testing is an aluminum profile pressure testing machine. The testing standard is GB / T6892-2015 General Industrial Aluminum and Aluminum Alloy Extruded Profiles, and the testing method is in accordance with GB / T32790-2016 Test Method for Welding Performance of Extruded Welds of Aluminum and Aluminum Alloys.

[0075] Low-magnification testing equipment: alkaline corrosive solution. The testing standard is GB / T6892-2015 General industrial aluminum and aluminum alloy extruded profiles. The testing method is in accordance with GB / T3246.2-2012 Deformed aluminum and aluminum alloy products, microstructure inspection method, part 2: low-magnification microstructure inspection method.

[0076] The bending performance testing equipment is the AG-X 100KN electronic universal testing machine. The testing standard is VDA238-100 Standard for Testing the Bending Performance of Metallic Materials.

[0077] The exfoliation corrosion performance test equipment is a digital display constant temperature water bath. The test standard is GB / T22639-2008 Exfoliation Corrosion Test Method for Aluminum Alloy Processed Products.

[0078] Intergranular corrosion susceptibility testing equipment: AXIO universal research-grade inverted materials microscope, and the testing standard is GB / T 7998-2027 "Test Method for Evaluation of Intergranular Corrosion Susceptibility of Aluminum Alloys".

[0079] Impact resistance test: The profile was impacted from bottom to top using impact heads with a diameter of 25 and 30 mm and an energy of 150 J.

[0080] The technical solution of the present invention will be further described in detail below with reference to the embodiments. Obviously, the embodiments described herein are only some embodiments of the present invention and are not intended to limit the present invention. All other embodiments implemented by those skilled in the art based on the embodiments of the present invention without creative improvements are within the protection scope of the present invention.

[0081] Example 1

[0082] The components and their weight percentages in the aluminum alloy profile are as follows: Si content 0.70%; Fe content 0.10%; Cu content 0.13%; Mn content 0.23%; Mg content 0.56%; Cr content 0.18%; Zn content 0.002%; Ti content 0.03%; Er content 0.18%; Zr content 0.13%; balance Al, with individual impurity content ≤0.05% and total content of other impurity elements ≤0.15%.

[0083] Melting and casting process: melting temperature 735℃, refining temperature 740℃, refining agent dosage 1.5kg / TAl, refining time 25min, slag removal temperature 733℃, converter temperature 750℃, settling temperature 720℃, no addition of scrap aluminum is allowed, the slag content of the ingot must meet the secondary requirements in GB / T32186-2015, hydrogen element 0.15ml / 100g;

[0084] Homogenization: A two-stage homogenization process of 380℃×6h+566℃×6h was adopted.

[0085] Extrusion process: A 5500T horizontal extruder is selected, with a casting rod length of 600mm, a casting rod temperature (i.e., extrusion ingot temperature) of 503℃, a die temperature of 495℃, a profile exit temperature of 523℃, and an extrusion speed of 2.2m / min.

[0086] Cooling: After extrusion, the profile passes through a water spray zone where water is sprayed onto the upper and lower surfaces for gradient cooling. The water flow rate is 0.73 m³ / s for the first 25% of the spray zone. 3 The cooling rate is 7.2℃ / s, which cools the extruded profile to 450℃. Then, in the 25-75% section of the water spraying area, the water flow rate is 6.5m³ / h. 3 The cooling rate is 33℃ / s, which cools the extruded profile to 150℃. Finally, in the last 25% of the water spraying area, the water flow rate is 3m³ / h. 3 The cooling rate is 145℃ / s / h, which cools the extruded profile down to 21℃.

[0087] Time limit: The time limit system is 195℃×12h.

[0088] A high-toughness, impact-resistant aluminum alloy profile A1 for automotive battery packs was produced.

[0089] The external dimensions are 366.75*9mm, the panel wall thickness is 2mm, the vertical rib structure has an inner rib thickness of 2.5mm, the 13-hole flat cavity has a length of 24mm, the cavity height is 5mm, the inner cavity radius is R2.0mm, and the outer radius is R1.0mm.

[0090] Example 2

[0091] The components and their weight percentages in the aluminum alloy profile are as follows: Si content 0.70%; Fe content 0.10%; Cu content 0.12%; Mn content 0.23%; Mg content 0.56%; Cr content 0.18%; Zn content 0.002%; Ti content 0.03%; Er content 0.19%; Zr content 0.14%; balance Al, with individual impurity content ≤0.05% and total content of other impurity elements ≤0.15%.

[0092] Melting and casting process: melting temperature 735℃, refining temperature 740℃, refining agent dosage 1.5kg / TAl, refining time 25min, slag removal temperature 735℃, converter temperature 750℃, settling temperature 720℃, no addition of scrap aluminum is allowed, the slag content of the ingot must meet the secondary requirements in GB / T32186-2015, and hydrogen element 0.15ml / 100g;

[0093] Homogenization: A two-stage homogenization process of 380℃×6h+565℃×6h was adopted.

[0094] Extrusion process: A 5500T horizontal extruder is selected, with a casting rod length of 600mm, a casting rod temperature (i.e., extrusion ingot temperature) of 508℃, a die temperature of 490℃, a profile exit temperature of 524℃, and an extrusion speed of 2.0m / min.

[0095] Cooling: After extrusion, the profile passes through a water spray zone where water is sprayed onto the upper and lower surfaces for gradient cooling. The water flow rate is 0.68 m³ / s for the first 25% of the spray zone. 3 The cooling rate is 7℃ / s, which cools the extruded profile to 450℃. Then, in the 25-75% section of the water spraying area, the water flow rate is 6.3m³ / h. 3 The cooling rate is 32℃ / s / h, which cools the extruded profile to 150℃. Finally, in the last 25% of the water spray area, the water flow rate is 2.8m³ / h. 3 The cooling rate is 138℃ / s / h, which cools the extruded profile down to 20℃.

[0096] Time limit: The time limit system is 195℃×12h.

[0097] A high-toughness, impact-resistant aluminum alloy profile A2 for automotive battery packs was produced.

[0098] The external dimensions are 366.75*9mm, the panel wall thickness is 2mm, the vertical rib structure has an inner rib thickness of 2.5mm, the 13-hole flat cavity has a length of 24mm, the cavity height is 5mm, the inner cavity radius is R2.0mm, and the outer radius is R1.0mm.

[0099] Example 3

[0100] The components and their weight percentages in the aluminum alloy profile are as follows: Si content 0.65%; Fe content 0.10%; Cu content 0.11%; Mn content 0.19%; Mg content 0.55%; Cr content 0.15%; Zn content 0.002%; Ti content 0.02%; Er content 0.13%; Zr content 0.10%; balance Al, with individual impurity content ≤0.05% and total content of other impurity elements ≤0.15%.

[0101] Melting and casting process: melting temperature 710℃, refining temperature 730℃, refining agent dosage 1.5kg / TAl, refining time 25min, slag removal temperature 733℃, converter temperature 750℃, settling temperature 720℃, no addition of scrap aluminum is allowed, the slag content of the ingot must meet the secondary requirements in GB / T32186-2015, and hydrogen element 0.15ml / 100g;

[0102] Homogenization: A two-stage homogenization process of 377℃×6h+562℃×6h was adopted.

[0103] Extrusion process: A 5500T horizontal extrusion press is selected, with a casting rod length of 600mm, a casting rod temperature (i.e., extrusion ingot temperature) of 505℃, a die temperature of 480℃, a profile exit temperature of 510℃, and an extrusion speed of 2m / min.

[0104] Cooling: After extrusion, the profile passes through a water spray zone where water is sprayed onto the upper and lower surfaces for gradient cooling. The water flow rate is 0.6 m³ / s for the first 25% of the spray zone. 3 The cooling rate is 5℃ / s, which cools the extruded profile to 450℃. Then, in the 25-75% section of the water spraying area, the water flow rate is 5m³ / h. 3 The cooling rate is 20℃ / s, which cools the extruded profile to 150℃. Finally, in the last 25% of the water spraying area, the water flow rate is 2m³ / h. 3 The cooling rate is 100℃ / s / h, which cools the extruded profile down to 20℃.

[0105] The heat dissipation difference of the profile in the first 25% of the water spray area exceeds 30°C; adjust the water flow rate to 0.5-0.6 m³ / h. 3 / h.

[0106] Time limit: The time limit is 192℃×12h.

[0107] A high-toughness, impact-resistant aluminum alloy profile A3 for automotive battery packs was produced.

[0108] The external dimensions are 366.75*9mm, the panel wall thickness is 2mm, the vertical rib structure has an inner rib thickness of 2.5mm, the 9-hole flat cavity has a length of 20mm, the cavity height is 5mm, the inner cavity radius is R2.0mm, and the outer radius is R1.0mm.

[0109] Example 4

[0110] The components and their weight percentages in the aluminum alloy profile are as follows: Si content 0.70%; Fe content 0.19%; Cu content 0.16%; Mn content 0.24%; Mg content 0.60%; Cr content 0.20%; Zn content 0.09%; Ti content 0.05%; Er content 0.20%; Zr content 0.15%; balance Al, with individual impurity content ≤0.05% and total content of other impurity elements ≤0.15%.

[0111] Melting and casting process: melting temperature 760℃, refining temperature 750℃, refining agent dosage 1.5kg / TAl, refining time 25min, slag removal temperature 735℃, converter temperature 750℃, settling temperature 720℃, no addition of scrap aluminum is allowed, the slag content of the ingot must meet the secondary requirements in GB / T32186-2015, and hydrogen element 0.15ml / 100g;

[0112] Homogenization: A two-stage homogenization process of 383℃×7h+568℃×8h was adopted.

[0113] Extrusion process: A 5500T horizontal extruder is selected, with a casting rod length of 600mm, a casting rod temperature (i.e., extrusion ingot temperature) of 520℃, a die temperature of 500℃, a profile exit temperature of 550℃, and an extrusion speed of 3m / min.

[0114] Cooling: After extrusion, the profile passes through a water spray zone where water is sprayed onto the upper and lower surfaces for gradient cooling. The water flow rate is 0.9 m³ / s for the first 25% of the spray zone. 3 The cooling rate is 10℃ / s / h, which cools the extruded profile to 450℃. Then, in the 25-75% section of the water spraying area, the water flow rate is 7m³ / h. 3 The cooling rate is 40℃ / s, which cools the extruded profile to 150℃. Finally, in the last 25% of the water spraying area, the water flow rate is 3m³ / h. 3 The cooling rate is 150℃ / s / h, which cools the extruded profile down to 30℃.

[0115] Time limit: The time limit is 198℃×14h.

[0116] A high-toughness, impact-resistant aluminum alloy profile A4 for automotive battery packs was produced.

[0117] The external dimensions are 366.75*9mm, the panel wall thickness is 2mm, the vertical rib structure has an inner rib thickness of 2.5mm, the 14-hole flat cavity has a length of 24mm, the cavity height is 5mm, the inner cavity radius is R2.0mm, and the outer radius is R1.0mm.

[0118] Comparative Example 1

[0119] Aluminum alloy profiles were prepared according to the preparation method of Example 1, except that the components and their weight percentages in the aluminum alloy profiles were as follows: Si content was 0.70%; Fe content was 0.10%; Cu content was 0.13%; Mn content was 0.20%; Mg content was 0.56%; Cr content was 0.17%; Zn content was 0.002%; Ti content was 0.03%; Er content was 0.13%; and Zr content was 0.15%, thus obtaining aluminum alloy profile DA1.

[0120] Comparative Example 2

[0121] Aluminum alloy profile DA2 was prepared according to the preparation method of Example 1, except that the outer dimensions were 366.75*9mm, the panel wall thickness was 2mm, the vertical rib structure had an inner rib thickness of 2mm, the flat cavity with 13 holes had a length of 30mm, a cavity height of 5mm, an inner cavity radius of R1mm, and an outer radius of R1mm.

[0122] Comparative Example 3

[0123] Aluminum alloy profiles were prepared according to the preparation method of Example 1, except that the cooling process involved passing the extruded profile through a water spraying zone, where water was sprayed onto the upper and lower surfaces of the extruded profile for gradient cooling. The water flow rate was 0.3 m³ / s for the first 25% of the water spraying zone. 3 The cooling rate is 3.2℃ / s, which cools the extruded profile to 450℃. Then, in the 25-75% section of the water spraying area, the water flow rate is 3.5m³ / h. 3 The cooling rate is 14.5℃ / s / h, which cools the extruded profile to 150℃. Finally, in the last 25% of the water spray area, the water flow rate is 3m³ / h. 3 The cooling rate is 150℃ / s, which cools the extruded profile to 20℃, thus producing aluminum alloy profile DA3.

[0124] Comparative Example 4

[0125] Aluminum alloy profiles were prepared according to the preparation method of Example 1, except that the cooling process involved passing the extruded profile through a water spraying zone, where water was sprayed onto the upper and lower surfaces of the extruded profile for gradient cooling. The water flow rate was 0.4 m³ / s for the first 25% of the water spraying zone. 3The cooling rate is 4.2℃ / s, which cools the extruded profile to 450℃. Then, in the 25-75% section of the water spraying area, the water flow rate is 4m³ / h. 3 The cooling rate is 16.5℃ / s / h, which cools the extruded profile to 150℃. Finally, in the last 25% of the water spray area, the water flow rate is 3m³ / h. 3 The cooling rate is 150℃ / s, which cools the extruded profile to 20℃, thus producing aluminum alloy profile DA4.

[0126] Comparative Example 5

[0127] Aluminum alloy profiles were prepared according to the preparation method of Example 1, except that water mist was used for cooling, resulting in aluminum alloy profile DA5.

[0128] Comparative Example 6

[0129] Aluminum alloy profiles were prepared according to the preparation method of Example 1, except that a homogenization process of 350℃×6h+560℃×6h was used to obtain aluminum alloy profile DA6.

[0130] Comparative Example 7

[0131] Aluminum alloy profiles were prepared according to the preparation method of Example 1, except that a homogenization process of 420℃×6h+570℃×6h was used to obtain aluminum alloy profile DA7.

[0132] Comparative Example 8

[0133] Aluminum alloy profiles were prepared according to the preparation method of Example 1, except that the aging regime was 195℃×10h, and aluminum alloy profile DA8 was obtained.

[0134] Comparative Example 9

[0135] Aluminum alloy profiles were prepared according to the preparation method of Example 1, except that the aging regime was 200℃×12h, and aluminum alloy profile DA9 was obtained.

[0136] The profiles prepared in Examples 1-4 and Comparative Examples 1-9 were tested, and the test results are shown in Tables 1 and 2.

[0137] Table 1

[0138]

[0139] Table 2

[0140]

[0141] The sample size for the bending performance test is 20*30*2mm.

[0142] By comparing the examples and comparative examples, it can be seen that the aluminum alloy profiles prepared in Examples 1-4 have good formability, high toughness, impact resistance without cracking, and corrosion resistance. When used as profiles for automotive battery packs, they can improve the protective performance of the battery pack housing, reduce the reliance on other protective materials in the design of the battery pack protective structure, and effectively reduce weight, which is more in line with the requirements for lightweighting and safe driving in the development of new energy vehicles.

[0143] Instruction manual attached Figure 1 and Figure 4 The metallographic high-magnification images of profiles A1 and A2 are shown respectively. It can be seen that the matrix grains of the profiles in Example 1 and Example 2 are fine and uniform with high grain size. No coarse grains or overheating phenomena such as molten spheres were found in the microstructure. The surface cortex layer is thin, dense and continuous, and the overall microstructure is good.

[0144] Instruction manual attached Figure 2 and Figure 5 The figures show the intergranular corrosion sensitivity test results for profiles A1 and A2, respectively. It is clear from the figures that no corrosion has occurred.

[0145] Instruction manual attached Figure 3 and Figure 6 The images show the impact test results for profiles A1 and A2, respectively. It can be clearly seen from the images that there is slight orange peel around the dent, but no cracks are found. The protrusions on the back of the sample are slight, which shows that the profile provided by this invention is impact-resistant and does not crack. When used in automotive battery packs, it can improve the protective performance of the battery pack housing.

[0146] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-toughness, impact-resistant aluminum alloy profile for automotive battery packs, characterized in that, The components and their weight percentages in the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs are as follows: Si content 0.65-0.70%; Fe content < 0.20%; The Cu content is 0.11-0.16%; The Mn content is 0.19-0.24%; The Mg content is 0.55-0.60%; The Cr content is 0.15-0.20%; Zn content < 0.10%; The Ti content is 0.02-0.05%; Er content is 0.13-0.20%; The Zr content is 0.10-0.15%; Mn / Cr≥1.2, 1.6≥Er / Zr≥1.3; The content of a single impurity is ≤0.05%; The total content of other impurity elements is ≤0.15%; The margin is Al.

2. The high-toughness, impact-resistant aluminum alloy profile for automotive battery packs according to claim 1, characterized in that, The high-toughness, impact-resistant aluminum alloy profile used in the automotive battery pack has a vertical rib structure. The automotive battery pack uses a high-toughness, impact-resistant aluminum alloy profile with 9-14 holes in a flat cavity. The openings of the flat cavity are on the left and right sides of the profile. The length of the flat cavity is 20-24 mm, the height of the flat cavity is 5 mm, the inner corner radius of the flat cavity is R2.0-R2.5 mm, and the outer corner radius is R1.0 mm.

3. The high-toughness, impact-resistant aluminum alloy profile for automotive battery packs according to claim 2, characterized in that, The wall thickness of the high-toughness, impact-resistant aluminum alloy profile used in the automotive battery pack is 1.8-2.2mm, and the thickness of the inner rib is 2-2.5mm.

4. A method for preparing a high-toughness, impact-resistant aluminum alloy profile for an automotive battery pack according to any one of claims 1-3, characterized in that, The preparation method includes smelting, casting, homogenization, extrusion, cooling, and aging; The cooling conditions include: the extruded profile passes through a water spraying area, and water is sprayed onto the upper and lower surfaces of the extruded profile for gradient cooling. The conditions for gradient cooling include: a water flow rate of 0.6-0.9 m³ / s for the first 25% of the spray zone. 3 The cooling rate is 5-10℃ / s, which cools the extruded profile to 450℃. Then, in the 25-75% section of the water spraying area, the water flow rate is 5-7m³ / h. 3 The cooling rate is 20-40℃ / s, which cools the extruded profile to 150℃. Finally, in the last 25% of the water spraying area, the water flow rate is 2-3m³ / h. 3 The cooling rate is 100-150℃ / s / h, which cools the extruded profile to 20-30℃.

5. The method for preparing the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs according to claim 4, characterized in that, If, within 25-75% of the spray area, the temperature difference in heat dissipation of the profile passing through the first 25% of the spray area exceeds 30°C, the water flow rate should be reduced to 0.5-0.6 m³ / h. 3 / h.

6. The method for preparing the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs according to claim 4, characterized in that, The homogenization conditions include: a homogenization regime of (377-383)℃ × (6-7)h + (562-568)℃ × (6-8)h.

7. The method for preparing the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs according to claim 4, characterized in that, The extrusion conditions include: die temperature of 480-500℃, extrusion ingot temperature of 500-520℃, profile exit temperature of 510-550℃, and extrusion speed of 2-3m / min.

8. The method for preparing the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs according to claim 4, characterized in that, The conditions for the aging period include: the aging regime is (192-198)℃ × (12-14)h.

9. The method for preparing the high-toughness, impact-resistant aluminum alloy profile for automotive battery packs according to claim 4, characterized in that, The smelting conditions include: a melting temperature of 710-760℃ and a refining temperature of 730-750℃.

Images