Aluminum-iron-silicon alloy, its preparation method and application

Abstract

The application discloses an aluminum-silicon-iron alloy and a preparation method and application thereof, wherein the aluminum-silicon-iron alloy at least comprises: the mass ratio sum of Fe and Si is 0.7%, Fe is 0.24-0.60 wt%, and Si is 0.10-0.46 wt%. The Pandat2020 software is used to carry out point calculation on the aluminum-silicon-iron alloy in the component range, precise regulation and control design of two main iron-rich phase organizations in the alloy plate are completed, effective cooperation between surface segregation of the continuously-cast and-rolled aluminum-silicon-iron alloy continuously-cast slab and final cold-rolled aluminum foil mechanical properties is realized, and finally, high-performance continuously-cast and-rolled aluminum foil products for lithium ion battery positive electrode current collectors are obtained. Through the precise regulation and control of the iron-rich phase organization, the surface segregation of the continuously-cast and-rolled aluminum-silicon-iron alloy slab in the short process production is effectively controlled, and the mechanical properties and forming properties of the final processed aluminum foil are significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy processing technology, and relates to an aluminum-iron-silicon alloy, its preparation method and application. Background Technology

[0002] Using pure aluminum as the base material, adding other alloying elements can improve the strength, ductility, and toughness of aluminum alloys while maintaining good forming performance. Currently, Al-Fe-Si alloys (aluminum-iron-silicon alloys) are generally produced by optimizing the alloy composition from the source by adding alloying elements, thereby improving the performance of the aluminum alloy.

[0003] Short-process aluminum foil manufacturing is increasingly favored by aluminum processing companies due to its advantages such as shorter process flow, lower energy consumption, and lower production costs. However, because continuous casting and rolling eliminates processes like billet homogenization, the billet's properties are affected by the alloy microstructure, which in turn influences the properties of subsequently rolled aluminum alloy sheets. Therefore, short-process manufacturing suffers from more severe segregation defects compared to traditional processes. Aluminum alloys contain numerous types of iron-rich phases, each playing a different role in the alloy matrix and affecting its mechanical properties. However, current research and development on short-process aluminum foil manufacturing technologies such as continuous casting and rolling are relatively limited.

[0004] Aluminum-iron-silicon alloys possess low density, good electrical conductivity, corrosion resistance, and good formability, making them widely used in battery equipment, chemical products, and food packaging. With increasing attention being paid to aluminum alloys in the new energy sector, the performance requirements for aluminum foil used in lithium-ion batteries are becoming increasingly stringent. For example, aluminum alloys for lithium-ion batteries need to have a flawless, glossy surface, excellent sheet shape control, and meet higher strength and ductility requirements given the trend of increasingly thinner aluminum alloy sheets. This still presents certain challenges to the performance of currently available aluminum alloys. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides an aluminum-iron-silicon alloy in a first aspect, a method for preparing the aluminum-iron-silicon alloy in a second aspect, and an application of the aluminum-iron-silicon alloy in the preparation of the positive electrode current collector of a lithium-ion battery in a third aspect.

[0006] One of the objectives of this invention is achieved through the following technical solution:

[0007] An aluminum-iron-silicon alloy, by mass percentage of elements, comprises at least: 0.24%-0.60% Fe and 0.10%-0.46% Si, wherein the total amount of Fe and Si is 0.7%.

[0008] In some embodiments, the iron-silicon atomic ratio is (1-3):(1-4).

[0009] In some implementations, it also includes: Mn 0-1.2%.

[0010] The second objective of this invention is achieved by the following technical solution:

[0011] A method for preparing an aluminum-iron-silicon alloy includes: providing an aluminum melt; adding at least an aluminum-iron master alloy and an aluminum-silicon master alloy to the aluminum melt to perform aluminum-iron-silicon alloying; refining the aluminum-iron-silicon alloy after melting to obtain the aluminum-iron-silicon alloy; wherein, based on the elemental mass percentage content, the aluminum-iron-silicon alloy comprises at least: Fe 0.24%-0.60% and Si 0.10%-0.46%.

[0012] In some embodiments, the process further includes: continuously casting, cold rolling and annealing the aluminum-iron-silicon alloy to prepare aluminum foil.

[0013] In some embodiments, the aluminum foil has a thickness of 7 μm; the aluminum foil has a tensile strength of 140.3-154.9 MPa, an elongation of 3.65%-5.68%, and a cupping value of 6.13-6.87 mm.

[0014] In some embodiments, at least an aluminum-iron master alloy and an aluminum-silicon master alloy are added to the aluminum melt for aluminum-iron-silicon alloying, and the process further includes adding an aluminum-manganese master alloy to the aluminum melt.

[0015] In some embodiments, the aluminum-iron-silicon alloy is subjected to continuous casting, cold rolling, and annealing to prepare aluminum foil.

[0016] In some embodiments, the aluminum foil has a thickness of 7 μm; the aluminum foil has a tensile strength of 154.5-210.9 MPa, an elongation of 3.37%-8.08%, and a cupping value of 5.91-7.71 mm.

[0017] The third objective of this invention is achieved by the following technical solution:

[0018] The aluminum-iron-silicon alloy of the first aspect of this application and the aluminum-iron-silicon alloy prepared by the preparation method of the second aspect are used in the preparation of positive electrode current collectors for lithium-ion batteries.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This invention discloses an aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plate, its preparation method, and its applications. The alloy or alloy plate, by elemental mass percentage, comprises at least: Fe 0.24–0.60% and Si 0.10–0.46%, wherein the total amount of Fe and Si is 0.7%. This invention achieves microstructure control and improved mechanical properties of the alloy, alleviates problems such as easy segregation on the surface of alloy billets used in lithium battery production by casting and rolling, and improves the surface quality of the billets and subsequent plates.

[0021] Unlike the trial-and-error method used in traditional alloy production, this invention designs the alloy composition based on phase diagram simulation and thermodynamic calculations using Pandat software. By changing the Fe / Si atomic ratio, the Fe and Si content in the aluminum-iron-silicon alloy is controlled, resulting in different microstructures to reduce surface segregation. Successful forming of the sheet is achieved through setting rolling process parameters. Pandat 2020 software is used to perform point calculations on aluminum-iron-silicon alloys within this composition range, completing the precise control design of the two main iron-rich phases (α and β phases) in the alloy sheet. This achieves effective synergy between surface segregation in continuously cast and rolled aluminum-iron-silicon slabs and the final mechanical properties of cold-rolled aluminum foil, ultimately yielding high-performance continuously cast and rolled aluminum-iron-silicon aluminum foil products for lithium-ion battery cathode current collectors. This invention effectively controls surface segregation in short-process production of aluminum-iron-silicon alloy slabs, such as continuous casting and rolling, through precise control of the iron-rich phase structure, significantly improving the mechanical and forming properties of the final processed aluminum foil.

[0022] Furthermore, this invention solves the problem of poor surface quality of cast billets caused by the easy segregation of iron-rich phases in aluminum-iron-silicon alloys, thereby optimizing the strength, toughness, and formability of aluminum-iron-silicon alloys. Attached Figure Description

[0023] Figure 1 To obtain the phase composition ratio evolution diagram of FS14 alloy at different temperatures through calculation and simulation for this application point;

[0024] Figure 2 This application uses Pandat to calculate and simulate contour maps of aluminum-iron-silicon alloys with different Fe and Si compositions.

[0025] Figure 3 These are scanning electron microscope (SEM) images of the aluminum-iron-silicon alloy plates obtained in Examples 1 to 5 of this application;

[0026] Figure 4 These are scanning electron microscope (SEM) images of the aluminum-iron-silicon alloy ingots obtained in Examples 6 to 10 of this application. Detailed Implementation

[0027] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0028] The inventors of this application employ precise composition design based on thermodynamic simulation. Specifically, this includes using the Point Calculation function of the phase diagram module in the PanphaseDiagram of Pandat 2020 software to perform point calculations on aluminum-iron-silicon alloys. This involves calculating the types and contents of the microstructure within the alloy at equilibrium at a specific temperature for a given composition. Based on the calculation results, the Fe and Si content in the aluminum-iron-silicon alloy is precisely controlled by changing the Fe / Si atomic ratio, resulting in different atomic ratios with different iron-rich phase structures. Table 1 shows the aluminum-iron-silicon alloys with different Fe and Si contents and the iron-rich phase characteristics designed based on thermodynamic simulation.

[0029] Table 1

[0030] alloy Fe / Si atomic ratio Fewt% Siwt% Alwt% Microstructure FS14 1:4 0.24 0.46 margin β-AlFeSi FS11 1:1 0.46 0.24 margin β-AlFeSi (mainly) and α-AlFeSi FS32 3:2 0.52 0.18 margin β-AlFeSi and α-AlFeSi FS21 2:1 0.56 0.14 margin α-AlFeSi (mainly) and β-AlFeSi FS31 3:1 0.60 0.10 margin α-AlFeSi

[0031] As shown in Table 1, when the Fe content in the aluminum-iron-silicon alloy is 0.24 wt% and the Si content is 0.46 wt%, the microstructure of the resulting aluminum-iron-silicon alloy is entirely composed of β-phase AlFeSi (β-AlFeSi). When the Fe content in the aluminum-iron-silicon alloy is 0.46 wt% and the Si content is 0.24 wt%, the main phase of the microstructure of the resulting aluminum-iron-silicon alloy is β-phase AlFeSi, and the secondary phase is α-phase AlFeSi (α-AlFeSi). When the Fe content in the aluminum-iron-silicon alloy is 0.52 wt% and the Si content is 0.18 wt%, the microstructure of the resulting aluminum-iron-silicon alloy has comparable β-phase AlFeSi and α-phase AlFeSi. When the Fe content in the aluminum-iron-silicon alloy is 0.56 wt% and the Si content is 0.14 wt%, the main phase of the microstructure of the resulting aluminum-iron-silicon alloy is α-phase AlFeSi, and the secondary phase is β-phase AlFeSi. When the Fe content in the aluminum-iron-silicon alloy is 0.60 wt% and the Si content is 0.10 wt%, the microstructure of the resulting aluminum-iron-silicon alloy is entirely α-phase AlFeSi.

[0032] The alloy composition of the aluminum-iron-silicon alloy in Table 1 is based on the Pandat calculation design process. The Point Calculation function of the phase diagram module in the Pandat 2020 software's PanphaseDiagram was used to perform point calculations on the aluminum-iron-silicon alloy, i.e., to calculate the types and contents of the microstructure within the alloy at equilibrium at a certain temperature for an alloy with a given composition. After bringing up the point calculation dialog box in Pandat 2020 software and inputting the content of each element in the alloy, the software can export phase composition ratio evolution diagrams based on different element contents at different temperatures. Figure 1To obtain the phase composition ratio evolution diagram of FS14 alloy at different temperatures through point calculation simulation, a phase composition contour map can be plotted based on the phase composition ratio evolution diagram of aluminum-iron-silicon alloy at phase equilibrium with different Fe and Si element contents. Figure 2 High-line plots of phase composition for aluminum-iron-silicon alloys with different Fe and Si compositions based on Pandat are shown. Figure 2 As shown, based on Pandat phase diagram simulation calculations, by adjusting the Fe / Si atomic ratio and Mn content in aluminum-iron-silicon alloys, the microstructure of the alloy, including the control of iron-rich phases and surface segregation, optimization of the crystallization temperature range, and improvement of mechanical properties, can be achieved.

[0033] Example 1

[0034] An aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plate, based on the element mass percentage content, contains Fe: 0.24%, Si: 0.46%, wherein the total amount of Fe and Si is 0.7%, the Fe / Si atomic ratio is 1:4, and the balance is Al. This product is designated as FS14.

[0035] The preparation process of this FS14 aluminum-iron-silicon alloy includes the following steps:

[0036] (1) Alloy smelting

[0037] (1.1) Preparation of molten aluminum: After cleaning the smelting furnace, electrolytic aluminum liquid is added, with each batch of molten aluminum liquid weighing approximately 100t. Of this, the electrolytic aluminum liquid weighs approximately 78t, and the remelted aluminum ingot weighs approximately 22t. Subsequently, the remelted aluminum ingot is completely melted into molten aluminum in the electrolytic aluminum liquid in the smelting furnace to obtain molten aluminum.

[0038] (1.2) Aluminum-iron-silicon alloying: Based on the composition designed by the thermodynamic simulation of FS14 alloy in Table 1, aluminum-iron master alloy and aluminum-silicon master alloy were added to the aluminum melt in sequence according to the mass percentages of Fe, Si, and Al. The alloying temperature was 720-750℃ and the time was 10 min. The aluminum-iron master alloy was an AlFe10 master alloy ingot, which is a master alloy ingot with a Fe mass fraction of 10%. The aluminum-silicon master alloy was an AlSi20 master alloy ingot, which is a master alloy ingot with a Si mass fraction of 20%.

[0039] (1.3) Electromagnetic stirring and refining: After the intermediate alloy is completely melted, the melt is electromagnetically stirred in the melting furnace first clockwise and then counterclockwise for 20 minutes. After electromagnetic stirring, slag is immediately removed when the molten metal stabilizes. After slag removal, argon and chlorine are introduced as protective gases to refine the aluminum melt for 25-30 minutes. After refining, the aluminum melt flows into the front box and enters the continuous casting machine for casting at a temperature of 700-720℃ to obtain FS14 aluminum-iron-silicon alloy. The microstructure of FS14 is β-AlFeSi.

[0040] The aforementioned FS14 aluminum-iron-silicon alloy can also be used to prepare FS14 aluminum-iron-silicon alloy billets, including the following steps:

[0041] (2) Continuous casting

[0042] (2.1) The aluminum liquid is fed into the casting mold cavity through the casting nozzle. The upper and lower parts of the mold cavity are two steel strips that move in opposite directions. The required product width can be obtained by adjusting the spacing between the steel strips.

[0043] (2.2) The temperature of the molten aluminum injected into the continuous casting machine is maintained at 700-740℃, the casting speed is controlled at 8-10m / min, the cooling rate is 50-60℃ / s, the width of the continuous casting billet is 1900±50mm, and the thickness of the continuous casting billet is 19±1mm.

[0044] The aforementioned FS14 aluminum-iron-silicon alloy plate can also be used to prepare aluminum-iron-silicon alloy foil (hereinafter referred to as aluminum foil), including the following steps:

[0045] (3) Cold rolling and annealing

[0046] (3.1) Cold rolling: The alloy billet is cold rolled in multiple passes on a twin-roll mill, with a reduction rate of 15%-20% each time, which can refine the grains of the aluminum alloy and improve its strength.

[0047] (3.2) Intermediate annealing: In order to avoid stress concentration during rolling and cracking of the plate, intermediate annealing is carried out at 345℃ for 2 hours when the deformation of cold-rolled FS14 aluminum-iron-silicon alloy plate reaches 70% to eliminate residual stress.

[0048] (3.3) Continuous cold rolling: After intermediate annealing, the aluminum foil is continuously cold rolled to make the thickness less than 0.0070 mm.

[0049] (3.4) Stress-relief annealing: The obtained aluminum foil is subjected to stress-relief annealing with annealing parameters of 175℃×2h.

[0050] Example 2

[0051] An aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plate, based on the elemental mass percentage content, contains Fe: 0.46%, Si: 0.24%, with a total Fe and Si content of 0.7%, an Fe / Si atomic ratio of 1:1, and the balance being Al. This product is designated as FS11. The microstructure of FS11 has β-AlFeSi as the main phase and α-AlFeSi as the secondary phase.

[0052] The method for preparing aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plates and aluminum foil in Example 2 is the same as that in Example 1. The addition ratio of Al, Fe and Si involved in the preparation process is adjusted accordingly with reference to the mass ratio of the three elements in FS11 in Example 2.

[0053] Example 3

[0054] An aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plate, based on the elemental mass percentage content, contains Fe: 0.52%, Si: 0.18%, with a total Fe and Si content of 0.7%, an Fe / Si atomic ratio of 3:2, and the balance being Al. This product is designated as FS32. The microstructure of FS32 is equivalent to that of β-AlFeSi and α-AlFeSi.

[0055] The method for preparing aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plates and aluminum foil in Example 3 is the same as that in Example 1. The addition ratio of Al, Fe and Si involved in the preparation process is adjusted accordingly with reference to the mass ratio of the three elements in FS32 in Example 3.

[0056] Example 4

[0057] An aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plate, based on the elemental mass percentage content, contains Fe: 0.56%, Si: 0.14%, with a total Fe and Si content of 0.7%, an Fe / Si atomic ratio of 2:1, and the balance being Al. This product is designated as FS21. The main phase of the microstructure in FS21 is α-AlFeSi, and the secondary phase is β-AlFeSi.

[0058] The method for preparing aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plates and aluminum foil in Example 4 is the same as that in Example 1. The addition ratio of Al, Fe and Si involved in the preparation process is adjusted accordingly with reference to the mass ratio of the three elements in FS21 in Example 4.

[0059] Example 5

[0060] An aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plate, based on the elemental mass percentage content, contains Fe: 0.60%, Si: 0.10%, with a total Fe and Si content of 0.7%, an Fe / Si atomic ratio of 3:1, and the balance being Al. This product is designated as FS31. The microstructure of FS31 is α-AlFeSi.

[0061] The method for preparing aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plates and aluminum foil in Example 5 is the same as that in Example 1. The addition ratio of Al, Fe and Si involved in the preparation process is adjusted accordingly with reference to the mass ratio of the three elements in FS31 in Example 5.

[0062] Example 6

[0063] An aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plate may also include manganese. By mass percentage, it comprises: Fe: 0.24%, Si: 0.46%, with a total Fe and Si content of 0.7%, an Fe / Si atomic ratio of 1:4, and Mn content of 0.4%, 0.8%, or 1.2%, with the balance being Al. Products with this composition are designated as FS14Mn04, FS14Mn08, and FS14Mn12, respectively.

[0064] The aluminum-iron-silicon alloying step (1.2) in Example 1 is adjusted as follows: according to the proportions of Fe, Al, Si and Mn elements in different products in the previous section, aluminum-manganese master alloy is first added to the aluminum melt. After the aluminum-manganese master alloy is completely melted, aluminum-iron master alloy and aluminum-silicon master alloy are added to the aluminum melt in sequence. The master alloys must be preheated to 200°C before being added. The aluminum-manganese master alloy is AlMn10 master alloy ingot, which is a master alloy ingot with Mn mass fraction of 10% in the alloy; the aluminum-iron master alloy is AlFe10 master alloy ingot, which is a master alloy ingot with Fe mass fraction of 10% in the alloy; and the aluminum-silicon master alloy is AlSi20 master alloy ingot, which is a master alloy ingot with Si mass fraction of 20% in the alloy.

[0065] The remaining steps are the same as in Example 1, and FS14Mn04, FS14Mn08, and FS14Mn12 aluminum-iron-silicon alloys or aluminum-iron-silicon alloy plates and foils are prepared.

[0066] Example 7

[0067] An aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plate may also include manganese. By mass percentage, it comprises: Fe: 0.46%, Si: 0.24%, with a total Fe and Si content of 0.7%, an Fe / Si atomic ratio of 1:1, and Mn content of 0.4%, 0.8%, or 1.2%, with the balance being Al. Products with this composition are designated as FS11Mn04, FS11Mn08, and FS11Mn12, respectively.

[0068] The preparation methods of FS11Mn04, FS11Mn08, and FS11Mn12 aluminum-iron-silicon alloys or aluminum-iron-silicon alloy plates and aluminum foils in Example 7 are the same as those in Example 6. The mass ratios of Al, Fe, Si, and Mn involved in the preparation process are adjusted accordingly with reference to FS14Mn04, FS14Mn08, and FS14Mn12 in Example 7.

[0069] Example 8

[0070] An aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plate may also include manganese. By mass percentage, it comprises: Fe: 0.52%, Si: 0.18%, with a total Fe and Si content of 0.7%, an Fe / Si atomic ratio of 3:2, and Mn content of 0.4%, 0.8%, or 1.2%, with the balance being Al. Products with this composition are designated as FS32Mn04, FS32Mn08, and FS32Mn12, respectively.

[0071] The preparation methods of FS32Mn04, FS32Mn08, and FS32Mn12 aluminum-iron-silicon alloys or aluminum-iron-silicon alloy plates and aluminum foils in Example 8 are the same as those in Example 6. The mass ratios of Al, Fe, Si, and Mn involved in the preparation process are adjusted accordingly with reference to FS32Mn04, FS32Mn08, and FS32Mn12 in Example 8.

[0072] Example 9

[0073] An aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plate may also include manganese. By mass percentage, it comprises Fe: 0.56%, Si: 0.14%, with a total Fe and Si content of 0.7%, an Fe / Si atomic ratio of 2:1, and Mn content of 0.4%, 0.8%, or 1.2%, with the balance being Al. Products with this composition are designated as FS21Mn04, FS21Mn08, and FS21Mn12, respectively.

[0074] The preparation methods of FS21Mn04, FS21Mn08, and FS21Mn12 aluminum-iron-silicon alloys and aluminum-iron-silicon alloy plates in Example 9 are the same as those in Example 6. The mass ratios of Al, Fe, Si, and Mn involved in the preparation process are adjusted accordingly with reference to FS21Mn04, FS21Mn08, and FS21Mn12 in Example 9.

[0075] Example 10

[0076] An aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plate may also include manganese. By mass percentage, it comprises Fe: 0.60%, Si: 0.10%, with a total Fe and Si content of 0.7%, an Fe / Si atomic ratio of 3:1, and Mn content of 0.4%, 0.8%, or 1.2%, with the balance being Al. Products with this composition are designated as FS31Mn04, FS31Mn08, and FS31Mn12, respectively.

[0077] The preparation methods of FS31Mn04, FS31Mn08, and FS31Mn12 aluminum-iron-silicon alloys and aluminum-iron-silicon alloy plates in Example 10 are the same as those in Example 6. The mass ratios of Al, Fe, Si, and Mn involved in the preparation process are adjusted accordingly with reference to FS31Mn04, FS31Mn08, and FS31Mn12 in Example 10.

[0078] The surface segregation of the aluminum-iron-silicon alloys in Examples 1-10 above was observed using scanning electron microscopy (SEM). A QUANTA 200 SEM manufactured by FEI (Factory International, Inc., USA) was used. The specific analytical method was as follows: the metallographic sample was ground to 800# and then mechanically polished until a mirror-like surface was free of scratches before being placed under the SEM to observe the surface segregation. The surface segregation results of the aluminum-iron-silicon alloys in Examples 1-5 are as follows: Figure 3 As shown, the surface segregation of the aluminum-iron-silicon alloys in Examples 6 to 10 is as follows: Figure 4 As shown. By Figure 3 , Figure 4 It is known that when the α-AlFeSi content in the aluminum-iron-silicon alloy is high, the segregation degree of the alloy is aggravated; when the β-AlFeSi content in the aluminum-iron-silicon alloy is high, the segregation degree of the alloy is less. After adding Mn element in proportions as in Examples 6 to 10 of this application to the aluminum-iron-silicon alloy, the segregation degree of the alloy is reduced to a certain extent.

[0079] The aluminum-iron-silicon alloy or alloy plate / foil obtained in this application has a dense oxide film on its surface, which prevents the current collector from being corroded and oxidized by the electrolyte in the lithium-ion battery when used as a current collector in the positive electrode. Furthermore, the aluminum-iron-silicon alloy or alloy plate / foil of this application contains fewer elemental types, has a simpler microstructure, and a smaller potential difference with the substrate. Therefore, the aluminum foil prepared from the aluminum-iron-silicon alloy or alloy plate of this application has a higher oxidation potential, making it suitable as a current collector for the positive electrode of lithium-ion batteries.

[0080] Furthermore, this application also tested the tensile strength, elongation, and cupping value of aluminum foils with a thickness of less than 7 μm prepared in Examples 1 to 10 above. The test results are shown in Table 4. A universal testing machine from Shimadzu Corporation, Japan, model SFL-50KNAG, serial number N109001, was used. The specific method was as follows: tensile samples were cut by wire cutting machine at a tensile rate of 0.3 mm / min to obtain the tensile curve and read the tensile strength. Elongation: Before tensile testing, a gauge length L0 was prepared on the tensile specimen, and after tensile testing, the gauge length L1 was measured again. The elongation was obtained by the formula δ=(L1-L0) / L0. The forming properties of the alloy sheet were analyzed using a microcomputer-controlled fully automatic cupping testing machine, model CBZ-60D.

[0081] Table 2 shows the mass fraction of each component of the aluminum-iron-silicon alloys provided in Examples 1-5, Table 3 shows the mass fraction of each component of the aluminum-iron-silicon alloys provided in Examples 6-10, and Table 4 shows the mechanical and forming properties of each component of the aluminum-iron-silicon alloys provided in Examples 1-10.

[0082] Table 2

[0083] serial number Fe / wt% Si / wt% Al / wt% Example 1 0.24 0.46 margin Example 2 0.46 0.24 margin Example 3 0.52 0.18 margin Example 4 0.56 0.14 margin Example 5 0.60 0.10 margin

[0084] Table 3

[0085] serial number Fe / wt% Si / wt% Mn / wt% Al / wt% Example 6 0.24 0.46 0.40 margin Example 6 0.24 0.46 0.80 margin Example 6 0.24 0.46 1.20 margin Example 7 0.46 0.24 0.40 margin Example 7 0.46 0.24 0.80 margin Example 7 0.46 0.24 1.20 margin Example 8 0.52 0.18 0.40 margin Example 8 0.52 0.18 0.80 margin Example 8 0.52 0.18 1.20 margin Example 9 0.56 0.14 0.40 margin Example 9 0.56 0.14 0.80 margin Example 9 0.56 0.14 1.20 margin Example 10 0.60 0.10 0.40 margin Example 10 0.60 0.10 0.80 margin Example 10 0.60 0.10 1.20 margin

[0086] Table 4

[0087]

[0088]

[0089] In existing technologies, alloys processed using short-process methods exhibit more severe segregation defects compared to long-process methods. The aluminum foil of this application further regulates the ratio of α-AlFeSi to β-AlFeSi in the alloy by adjusting the proportions of Al, Fe, Si, or Al, Fe, Si, and Mn. Combined with short-process continuous casting and cold rolling, the resulting aluminum foil exhibits lower segregation and better mechanical properties, while significantly reducing energy consumption in the alloy preparation process compared to long-process methods. As shown in Table 4, the aluminum foil prepared in this application possesses good tensile strength, elongation, and cupping value, with tensile strength ranging from 140.3 to 210.9 MPa, elongation from 3.37% to 8.08%, and cupping value from 5.91 to 7.71 mm.

[0090] Therefore, the aluminum-iron-silicon alloy or aluminum-iron-silicon alloy plate and aluminum foil of this application realize the control of alloy microstructure, the improvement of mechanical properties, and the reduction of problems such as easy segregation on the surface of alloy billets for lithium batteries produced by casting and rolling, thereby improving the surface quality of billets and subsequent plates.

[0091] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. Use of an aluminum-iron-silicon alloy for the preparation of a positive current collector for lithium electronic batteries, characterized in that, The positive electrode current collector adopts an aluminum foil prepared from an aluminum-iron-silicon alloy, the thickness of the aluminum foil is 7 microns, the tensile strength of the aluminum foil is 154.5-210.9 MPa, the elongation is 3.37%-8.08%, and the cupping value is 5.91-7.71 mm; The aluminum-iron-silicon alloy comprises, in terms of element mass percentage, Fe 0.24%-0.60%, Si 0.10%-0.46%, Mn 0.4%-0.8%, and the balance of aluminum; wherein the total amount of Fe and Si is 0.7%, and the iron-silicon atomic ratio is (1-3):(1-4).

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