Aluminum foil, aluminum foil preparation method, electrode sheet, and battery

Abstract

The present application provides an aluminum foil, an aluminum foil preparation method, an electrode sheet, and a battery. The aluminum foil comprises the following components in percentage by mass: 0.15-0.20% of Fe, 0.05-0.10% of Si, 0.02-0.05% of Cu; 0.01-0.03% of Ti, and 0.02-0.2% of a rare earth element, the balance being Al and unavoidable impurities. The rare earth element component comprises at least one of La, Ce, Pr, Tb, and Yb, which is beneficial for improving the purity of the aluminum foil, reducing the enrichment of impurity elements in the aluminum foil, and increasing the elongation of the aluminum foil.

Description

Aluminum foil, aluminum foil preparation method, pole piece and battery

[0001] The present application claims priority to the Chinese patent application No. 202410871877.1 filed on June 28, 2024, and entitled "Aluminum foil, aluminum foil preparation method, pole piece and battery", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application belongs to the technical field of foil materials, in particular, the present application relates to an aluminum foil, an aluminum foil preparation method, a pole piece and a battery. BACKGROUND

[0003] Alloy aluminum foil is a commonly used material for battery current collectors, which has excellent electrical conductivity and stability. However, due to the low elongation of alloy aluminum foil, the deformation capacity of the current collector during the charging and discharging process of the battery is insufficient, which further affects the overall performance and safety of the battery. SUMMARY

[0004] An object of embodiments of the present application is to provide a new technical solution of an aluminum foil, an aluminum foil preparation method, a pole piece and a battery.

[0005] According to a first aspect of embodiments of the present application, an aluminum foil is provided, comprising the following components in terms of mass percentage:

[0006] Fe: 0.15-0.20%, Si: 0.05-0.10%, Cu: 0.02-0.05%, Ti: 0.01-0.03%, rare earth elements: 0.02-0.2%, and the balance of Al and unavoidable impurities;

[0007] The rare earth elements include at least one of La, Ce, Pr, Tb and Yb.

[0008] Optionally, the rare earth elements include La.

[0009] Optionally, the rare earth elements include La and Ce.

[0010] Optionally, the rare earth elements include La, Ce and Pr.

[0011] Optionally, the rare earth elements include La, Ce, Pr and Tb.

[0012] Optionally, the rare earth elements include La, Ce, Pr, Tb and Yb.

[0013] Optionally, the mass ratio of La to Ce is (0.5-2):1.

[0014] Optionally, the aluminum foil further contains B, and the content of B is 0.01%-0.05%.

[0015] Optionally, the tensile strength of the aluminum foil ranges from 200 MPa to 220 MPa, and the elongation of the aluminum foil is greater than or equal to 4.0%.

[0016] According to a second aspect of the embodiments of the present application, a preparation method of an aluminum foil is provided, comprising:

[0017] melting and processing aluminum-containing raw materials, iron-containing raw materials, silicon-containing raw materials, copper-containing raw materials, titanium-containing raw materials, and optional rare earth raw materials to obtain a first aluminum alloy liquid;

[0018] adding a refining agent to the first aluminum alloy liquid for refining treatment to obtain a second aluminum alloy liquid;

[0019] after cold rolling and annealing treatment, the second aluminum alloy liquid is subjected to foil rolling to obtain the aluminum foil of the first aspect.

[0020] Optionally, the melting and processing conditions include electromagnetic stirring, the temperature of the electromagnetic stirring ranges from 450°C to 750°C, and the time of the electromagnetic stirring ranges from 40 min to 70 min.

[0021] Optionally, the electromagnetic stirring comprises:

[0022] first-stage stirring the first aluminum alloy liquid, the temperature of the first-stage stirring ranges from 450°C to 550°C, and the time of the first-stage stirring ranges from 3 min to 5 min;

[0023] second-stage stirring the first aluminum alloy liquid, the temperature of the second-stage stirring ranges from 550°C to 650°C, and the time of the second-stage stirring ranges from 8 min to 10 min;

[0024] third-stage stirring the first aluminum alloy liquid, the temperature of the third-stage stirring ranges from 650°C to 750°C, and the time of the third-stage stirring ranges from 10 min to 20 min;

[0025] fourth-stage stirring the first aluminum alloy liquid, the temperature of the fourth-stage stirring ranges from 650°C to 750°C, and the time of the third-stage stirring ranges from 20 min to 30 min.

[0026] Optionally, the refining agent comprises at least one of Al-Ti-B-rare earth, LaB6, and Al-Ti-B-C-rare earth.

[0027] According to a third aspect of the embodiments of the present application, a pole piece is provided, comprising a current collector and an active material, the active material being coated on at least one side surface of the current collector;

[0028] the current collector adopts the aluminum foil of the first aspect.

[0029] According to a fourth aspect of the embodiments of the present application, a battery is provided, the battery comprising the pole piece of the third aspect.

[0030] One technical effect of the present application is that:

[0031] The embodiments of the present application provide an aluminum foil, the aluminum foil comprises the following components in percentage by mass: Fe: 0.15-0.20%, Si: 0.05-0.10%, Cu: 0.02-0.05%, Ti: 0.01-0.03%, rare earth elements: 0.02-0.2%, and the balance of Al and inevitable impurities; wherein the rare earth elements comprise at least one of La, Ce, Pr, Tb and Yb, which is beneficial to improve the purity of the aluminum foil, reduce the enrichment of impurity elements in the aluminum foil, and improve the elongation of the aluminum foil. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0033] FIG. 1 is a schematic view of a pole piece according to an embodiment of the present application.

[0034] EXPLANATION OF REFERENCE NUMERALS

[0035] 1 - current collector; 2 - active material. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. Note that the relative arrangement, numerical expressions, and numerical values of components and steps set forth in these embodiments are not limiting to the scope of the present application unless otherwise specifically stated.

[0037] Embodiments of the present application will be described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below by reference to the accompanying drawings are exemplary and are for the purpose of explaining the present application, and should not be understood as limiting the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts fall within the scope of the present application.

[0038] The terms "first", "second" in the description and claims of the present application can explicitly or implicitly include one or more features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / ", generally means that the front and rear associated objects are in an "or" relationship.

[0039] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0040] In the description of the present application, it needs to be understood that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0041] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further discussed in the subsequent drawings.

[0042] The embodiment of the present application provides an aluminum foil, the aluminum foil comprises the following components in percentage by mass:

[0043] Fe (iron): 0.15-0.20%, Si (silicon): 0.05-0.10%, Cu (copper): 0.02-0.05%, Ti (titanium): 0.01-0.03%, rare earth elements: 0.02-0.2%, the balance being Al (aluminum) and unavoidable impurities;

[0044] Among them, the rare earth elements include at least one of La (lanthanum), Ce (cerium), Pr (praseodymium), Tb (terbium) and Yb (ytterbium).

[0045] In this embodiment, the raw material of the aluminum foil can be a high-purity aluminum alloy, and the rare earth elements are doped, the high-purity aluminum alloy can be 1060 aluminum alloy or 1080 aluminum alloy, so as to reduce the content of components such as Fe, Si and Cu in the aluminum alloy.

[0046] Specifically, Fe, Si and Cu are easy to form compounds with aluminum, and the compounds are insoluble in the aluminum alloy solution, exist in the form of a second phase in the aluminum alloy solution, and are easy to reduce the purity and quality of the aluminum foil; and in the rolling process of the aluminum foil, the enrichment of Fe and Si can cause more impurities in the aluminum foil, thereby affecting the purity and electrical conductivity and other physical properties of the aluminum foil.

[0047] The purity of the aluminum alloy in the aluminum foil provided in the embodiments of the present application is higher, and the content of impurities such as Fe, Si, Cu and Ti is less, which is beneficial to improve the purity of the aluminum foil, reduce the enrichment of impurity elements in the aluminum foil, improve the elongation of the aluminum foil, enhance the deformation ability of the aluminum foil, and ensure the overall performance and safety of the battery using the aluminum foil.

[0048] In this embodiment, the content of impurities such as Mn, Mg and Zn is less, for example, Mn: 0.02-0.03%, Mg: <0.01%, and Zn: <0.01% by mass percentage, which can ensure the purity of the aluminum foil after forming.

[0049] The aluminum foil provided in the embodiments of the present application comprises the following components: Fe: 0.15-0.20%, Si: 0.05-0.10%, Cu: 0.02-0.05%, Ti: 0.01-0.03%, rare earth elements: 0.02-0.2%, and the balance of Al and unavoidable impurities; wherein the rare earth elements include at least one of La, Ce, Pr, Tb and Yb, which is beneficial to improve the purity of the aluminum foil, reduce the enrichment of impurity elements in the aluminum foil, and improve the elongation of the aluminum foil.

[0050] In one embodiment, the rare earth elements include La.

[0051] In this embodiment, when La is added to the aluminum foil, La can act as a nucleation center in the aluminum foil, and La can produce LaB compounds to play a role in homogenizing the grain structure; and La can improve the internal structure of the aluminum foil and improve the structural stability of the aluminum foil during the casting and rolling process of the aluminum foil.

[0052] In one embodiment, the rare earth elements include La and Ce.

[0053] In this embodiment, on the basis of the improvement of the internal structure of the aluminum foil by the La element, the Ce element can promote the formation of Al cubic texture in the aluminum foil, and the cubic texture can increase the specific surface area of the aluminum foil and increase the electrical conductivity of the aluminum foil.

[0054] In one embodiment, the rare earth elements include La, Ce and Pr.

[0055] In this embodiment, on the basis of the La element improving the internal structure of the aluminum foil and the Ce element increasing the specific surface area of the aluminum foil, the Pr element can refine the grains of the aluminum foil, and such grain refinement helps to improve the mechanical properties of the aluminum alloy, so that the aluminum foil has higher strength and better toughness.

[0056] In one embodiment, the rare earth elements include La, Ce, Pr, and Tb.

[0057] In this embodiment, on the basis of the La element improving the internal structure of the aluminum foil, the Ce element increasing the specific surface area of the aluminum foil, and the Pr element improving the strength and toughness of the aluminum foil, the Tb element can promote the generation of compounds in the aluminum foil and change the microstructure of the alloy, thereby improving the corrosion resistance of the aluminum foil.

[0058] In one embodiment, the rare earth elements include La, Ce, Pr, Tb, and Yb.

[0059] In this embodiment, on the basis of the La element improving the internal structure of the aluminum foil, the Ce element increasing the specific surface area of the aluminum foil, the Pr element improving the strength and toughness of the aluminum foil, and the Tb element improving the corrosion resistance of the aluminum foil, the Yb element can further improve the hardness and strength of the alloy, improve the microstructure and mechanical properties of the aluminum foil, and increase the corrosion resistance of the aluminum foil.

[0060] In one embodiment, the mass ratio of La to Ce is (0.5-2): 1.

[0061] In this embodiment, the aluminum foil includes, by mass percentage:

[0062] La: 0.01-0.1%; Ce: 0.01-0.1%.

[0063] Since La can act as a nucleation center in the aluminum foil, and La can produce LaB compounds, it plays a role in homogenizing the grain structure; and in the cast rolling process of the aluminum foil, La can improve the internal structure of the aluminum foil and improve the structural stability of the aluminum foil; and the Ce element can cooperate with La to promote the formation of Al cubic texture in the aluminum foil, and the cubic texture can increase the specific surface area of the aluminum foil and increase the electrical conductivity of the aluminum foil.

[0064] In one embodiment, the aluminum foil also contains B (boron), and the content of B is 0.01%-0.05%.

[0065] In this embodiment, B element is added to the aluminum foil in the form of a refiner, and B element forms compounds with Ti and rare earth elements in the aluminum foil, which can act as a nucleation center, refine the grains of the aluminum foil during cast rolling, so that the aluminum foil has higher strength and better toughness.

[0066] In one embodiment, the tensile strength of the aluminum foil ranges from 200-220 MPa, and the elongation of the aluminum foil is greater than or equal to 4.0%.

[0067] Adding rare earth elements to the aluminum alloy solution can form smaller and more uniformly distributed grains, while reducing the generation and growth of the second phase, making the aluminum grain structure more fine and uniform, thereby effectively increasing the elongation of the aluminum foil without reducing the strength of the aluminum foil.

[0068] The embodiments of the present application also provide a method for preparing an aluminum foil, which comprises:

[0069] S101, melting and processing aluminum-containing raw materials, iron-containing raw materials, silicon-containing raw materials, copper-containing raw materials, titanium-containing raw materials, and optional rare earth raw materials to obtain a first aluminum alloy liquid;

[0070] S102, adding a refining agent to the first aluminum alloy liquid for refining treatment to obtain a second aluminum alloy liquid;

[0071] S103, after the second aluminum alloy liquid is subjected to cold rolling and annealing treatment, foil rolling is performed to obtain the above-mentioned aluminum foil.

[0072] In this embodiment, the forming raw materials of the aluminum foil include aluminum alloy and a refining agent, the refining agent includes a refining component and a rare earth element component, and the rare earth element component includes at least one of La, Ce, Pr, Tb, and Yb.

[0073] During the forming of the aluminum foil, the refining agent can be added to the molten aluminum alloy solution, the refining component can promote the formation of crystal nuclei in the aluminum alloy, and the large grains can be refined into small particle sizes, which helps to improve the microstructure of the aluminum alloy, thereby improving the strength and elongation of the aluminum foil.

[0074] In one embodiment, adding the refining agent to the first aluminum alloy liquid for refining treatment can include adding a refining agent containing a rare earth raw material to the first aluminum alloy liquid in the melting process for refining treatment, or adding a refining agent containing a rare earth raw material to the first aluminum alloy liquid after melting for refining treatment. The refining agent containing a rare earth raw material can be at least one of Al-Ti-B-rare earth, LaB6, and Al-Ti-B-C-rare earth.

[0075] In one embodiment, the aluminum foil provided by the embodiments of the present application dopes the rare earth elements in the refining agent after melting, and adds the refining component and the rare earth element component together in the form of a refining agent to the liquid aluminum alloy solution, which can significantly reduce the hydrogen content in the aluminum alloy solution, reduce the porosity and impurity elements of the aluminum foil, and thereby improve the purity and deformation quality of the aluminum foil.

[0076] In one embodiment, the content of Si in the refiner is less than 0.10%, the content of Fe is less than 0.15%, the content of Ti is in the range of 4.4-4.6%, the content of rare earth element is in the range of 0.8-1.2%, the content of B is in the range of 0.7-1%, and the content of Al is in the range of 94-96%.

[0077] In one embodiment, the conditions of the melting process include electromagnetic stirring, the temperature of the electromagnetic stirring is 450-750℃, and the time of the electromagnetic stirring is 40-70min.

[0078] In the process of forming the aluminum foil, the refiner is added to the solution of the aluminum alloy in a filamentous form, and the solution of the aluminum alloy is subjected to electromagnetic stirring.

[0079] The electromagnetic stirring of the solution of the aluminum alloy after the refiner is added to the solution of the aluminum alloy in a filamentous form enables the rare earth element in the refiner to be better absorbed by the elements in the aluminum alloy, and enables the rare earth element to be more uniformly distributed in the aluminum foil.

[0080] Specifically, after the solution of the aluminum alloy is subjected to electromagnetic stirring, the solution of the aluminum alloy needs to further undergo the processes of casting-rolling, cold-rolling and foil-rolling, and the better absorption of the rare earth element by the elements in the aluminum alloy can reduce the contact of the rare earth element with the rolling elements in the processes of casting-rolling, cold-rolling and foil-rolling, thereby avoiding the formation of large-particle second-phase organizations in the processes of cold-rolling and foil-rolling, and ensuring the purity of the aluminum foil.

[0081] In one embodiment, the electromagnetic stirring includes:

[0082] The first-stage stirring of the first aluminum alloy liquid is performed at a temperature of 450-550℃ for a time of 3-5min;

[0083] The second-stage stirring of the first aluminum alloy liquid is performed at a temperature of 550-650℃ for a time of 8-10min;

[0084] The third-stage stirring of the first aluminum alloy liquid is performed at a temperature of 650-750℃ for a time of 10-20min;

[0085] The fourth-stage stirring of the first aluminum alloy liquid is performed at a temperature of 650-750℃ for a time of 20-30min.

[0086] In one specific embodiment, the electromagnetic stirring includes:

[0087] The first aluminum alloy liquid is subjected to first stage stirring when the first aluminum alloy liquid is melted by one third, the temperature of the first stage stirring is 450-550°C, and the time of the first stage stirring is 3-5 minutes;

[0088] The first aluminum alloy liquid is subjected to second stage stirring when the first aluminum alloy liquid is melted by one half, the temperature of the second stage stirring is 550-650°C, and the time of the second stage stirring is 8-10 minutes;

[0089] The first aluminum alloy liquid is subjected to third stage stirring when the first aluminum alloy liquid is melted by three thirds, the temperature of the third stage stirring is 650-750°C, and the time of the third stage stirring is 10-20 minutes;

[0090] The first aluminum alloy liquid is subjected to fourth stage stirring after the first aluminum alloy liquid is completely melted, the temperature of the fourth stage stirring is 650-750°C, and the time of the third stage stirring is 20-30 minutes.

[0091] In this embodiment, the electromagnetic stirring includes first stage stirring, second stage stirring, third stage stirring and fourth stage stirring;

[0092] The melted aluminum alloy is subjected to first stage stirring when the aluminum alloy is melted by one third;

[0093] The melted aluminum alloy is subjected to second stage stirring when the aluminum alloy is melted by one half;

[0094] The melted aluminum alloy is subjected to first stage stirring when the aluminum alloy is melted by two thirds;

[0095] The melted aluminum alloy is subjected to fourth stage stirring when the aluminum alloy is completely melted.

[0096] In this embodiment, the refining agent has been added to the aluminum alloy when the melted aluminum alloy is subjected to first stage stirring. The first stage stirring, the second stage stirring and the third stage stirring can melt the aluminum alloy ingot sufficiently, and filter the gas in the aluminum alloy solution through stirring, and remove the excessive oxygen component and carbon component in the aluminum alloy solution, so as to purify the aluminum solution and ensure the purity of the aluminum foil after forming.

[0097] The fourth stage stirring can be performed at a temperature of about 700°C, at which time the aluminum alloy has been completely melted into a solution, and the rare earth element can react with the aluminum alloy element to generate intermetallic compounds.

[0098] The forming process after electromagnetic stirring further includes casting, cold rolling, intermediate annealing, cold rolling and foil rolling, the intermetallic compound can be dispersedly distributed on the grain boundary of the aluminum foil during the cooling process, the hardness of the intermetallic compound is low and the intermetallic compound containing rare earth elements is easily damaged during the cold rolling process, and the damaged intermetallic compound containing rare earth elements can play a role in inhibiting grain growth after the intermediate annealing, so as to refine the grains before the foil rolling, so that the deformation of each part of the aluminum foil is uniform during the foil rolling process, and the yield of the aluminum foil obtained by the foil rolling is improved. Moreover, Fe and Si are also rarely aggregated due to the reaction with the rare earth elements, and the aggregation probability of the second phase in the aluminum foil is also greatly reduced, so as to ensure the elongation of the aluminum foil.

[0099] In this embodiment, the rare earth elements are doped in the refining agent after smelting, and the rare earth elements are added into the liquid aluminum alloy solution in the form of the refining agent, which can significantly reduce the hydrogen content in the aluminum alloy solution, reduce the porosity and impurity elements of the aluminum foil, and thus improve the purity and deformation quality of the aluminum foil.

[0100] In this embodiment, when the molten aluminum alloy is stirred in the first stage, the stirring temperature is 450-550℃, and the stirring time is 3-5min. The refining agent has been added to the aluminum alloy in this stage to avoid rapid melting of the refining agent at high temperature. The first stage stirring, the second stage stirring and the third stage stirring are continuously heated in the temperature range of 450-750℃, so that the aluminum alloy ingot can be fully melted, and the gas in the aluminum alloy solution can be filtered through stirring, and the excess oxygen and carbon components in the aluminum alloy solution can be removed to purify the aluminum solution and ensure the purity of the aluminum foil after forming.

[0101] The fourth stage stirring can be performed at a temperature of 650-750℃, such as at a temperature of 700℃. At this time, the aluminum alloy has been completely melted into a solution, and the rare earth elements can react with the aluminum alloy elements to form intermetallic compounds.

[0102] In a specific embodiment, the aluminum foil preparation method includes the following steps:

[0103] S201, the aluminum alloy ingot is added to the smelting furnace, the initial temperature of the smelting furnace is 770-800℃, the aluminum alloy ingot is partially melted and then kept for 10min, and then the smelting furnace is cooled to 700-750℃;

[0104] S202, the temperature of the aluminum alloy solution is controlled at 700-750℃, and the above refining agent is added to the aluminum flow tank in the form of a thin wire, the diameter of the thin wire is 8-10mm, and the adding speed is 1-1.5kg / min;

[0105] S203, the first stage stirring can be carried out when the aluminum alloy ingot is melted to one third of liquid state, the stirring time is 5 min, the second stage stirring can be carried out when the aluminum alloy ingot is melted to one half, the stirring time is 8-10 min, the third stage stirring is carried out when the aluminum alloy ingot is melted to three quarters, the stirring time is not more than 10 min; after the aluminum alloy ingot is completely melted, the fourth stage stirring is carried out in the process of adding the refiner, the stirring time is not more than 30 min, and the stirring frequency is 20-40 Hz;

[0106] S204, the solution after stirring is placed at a static furnace temperature of 700-750℃ for 6-20 min, and then casting and rolling is started, the casting and rolling speed is 900-1100 mm / min, and the thickness of the cast and rolled aluminum plate is 6.5-8 mm;

[0107] S205, first cold rolling, the first cold rolling adopts two passes, the first pass reduction is about 50%, the thickness of the aluminum plate is 3-4 mm, and the second pass reduction is 40-49%, the thickness of the aluminum plate is about 2 mm;

[0108] S206, intermediate annealing, the intermediate annealing temperature is 200-450℃, and the annealing time is 30-40 min;

[0109] S207, second cold rolling, the second cold rolling is three passes, the reduction of each pass is kept at 50%-60%, the thickness is rolled from 2 mm to 0.8-0.9 mm after the first pass rolling, the thickness is 0.4-0.45 mm after the second pass rolling, and the thickness is 0.2-0.22 mm after the third pass rolling, at this time, the aluminum blank is a foil rolling raw material blank;

[0110] S208, the foil blank with a thickness of 0.2-0.22 mm is subjected to four passes of foil rolling, the first pass is rough rolling, the middle two passes are medium rolling, and the last pass is finish rolling, the thickness is 90-100 μm after the first pass rolling, the thickness is 40-50 μm after the second pass rolling, the thickness is 20-25 μm after the third pass rolling, and the aluminum foil with a thickness of 13 μm is obtained after the last pass rolling.

[0111] In one embodiment, the refiner includes at least one of Al-Ti-B-rare earth, LaB6 and Al-Ti-B-C-rare earth.

[0112] In this embodiment, taking La and Ce rare earth elements as an example, the La and Ce rare earth elements are added to the aluminum alloy solution in the form of a refiner, which not only reduces the introduction of impurity elements from the process, but also improves the distribution and size of TiB2, making the TiB2 particles smaller and more uniform; in the formed aluminum foil, the La and Ce elements can act as nucleation centers for grain refinement along with the refining components to refine the grain size, while reducing the growth of La and Ce second phases.

[0113] Specifically, La and Ce directly affect the grain size and distribution of titanium boride and titanium aluminide in the refiner, which usually exists in the form of a second phase that acts as a nucleation center in the aluminum alloy solution, but the size of the second phase is relatively large, usually around 30 μm. The addition of La and Ce rare earth elements can improve the active energy of titanium and boron particles, reduce the aggregation of titanium boride and titanium aluminide, and make titanium boride and titanium aluminide particles disperse in the aluminum foil matrix, thereby enhancing the refining effect of the refiner.

[0114] In one embodiment, in Al-Ti-B, the mass ratio of Ti to B ranges from 3.5 to 5.5:1, which ensures sufficient TiB2 particle formation and effective grain refinement.

[0115] Referring to FIG. 1, the application provides a pole piece, which includes a current collector 1 and an active material 2 coated on at least one side surface of the current collector 1.

[0116] The current collector 1 uses the above-mentioned aluminum foil.

[0117] In this embodiment, the purity of the aluminum alloy in the above-mentioned aluminum foil is high, which makes the content of impurities such as Fe, Si, Cu, and Ti less, is conducive to improving the purity of the aluminum foil, reducing the enrichment of impurity elements in the aluminum foil, improving the elongation of the aluminum foil, enhancing the deformation ability of the aluminum foil, and ensuring the overall performance and safety of the battery using the aluminum foil.

[0118] The application provides a battery, which includes the above-mentioned pole piece.

[0119] In this embodiment, the battery includes a positive pole piece, a separator, and a negative pole piece, the separator is arranged between the positive pole piece and the negative pole piece, and the positive current collector in the positive pole piece uses the above-mentioned aluminum foil. The elongation of the aluminum foil is improved, which ensures the overall performance and safety of the battery.

[0120] The aluminum foil of the application will be described in detail below by using examples and comparative examples.

[0121] The mass percentage (wt%) and mass ratio of each element in each example and comparative example are shown in Table 1.

[0122] The mass percentage (wt%) of each element and the mass ratio of the aluminum foil of Table 1

[0123] The aluminum foil obtained in the above examples and comparative examples was tested:

[0124] Specifically, the above aluminum foil was subjected to a tensile test by using the sample and method for tensile test of wrought aluminum, magnesium and their alloy products in GB / T 16865-2013, and the aluminum foil tensile sample was 150 mm long and 15 mm wide, and the gauge length was 50 mm.

[0125] Table 2: Tensile strength and elongation test results of the aluminum foil

[0126] As can be seen from the test in Table 2, high-purity aluminum alloy is used in Examples 1 to 19, and rare earth elements are added, so that the tensile strength of the aluminum foil is above 200 MPa, and the elongation is above 4.1%, which ensures the deformation ability of the aluminum foil.

[0127] Comparative Examples 1 to 10 have lower or higher mass percentage of some component elements compared with Example 1, which results in tensile strength of the aluminum foil below 200 MPa, and elongation not higher than 3.8%, which limits the deformation ability of the aluminum foil.

[0128] The preparation method of the aluminum foil of the present application is described in detail below by using examples and comparative examples.

[0129] Example 101

[0130] (1) The aluminum-containing raw material, the iron-containing raw material, the silicon-containing raw material, the copper-containing raw material, the titanium-containing raw material and the rare earth raw material were added to a smelting furnace, the initial furnace temperature of the smelting furnace was 780℃, and after the aluminum alloy ingot was melted, it was kept at 735℃ for 10 min, and then cooled in the furnace to 735℃;

[0131] (2) When the temperature of the aluminum alloy solution was 735℃, the refiner (Al-Ti-B-rare earth) was added to the aluminum flow tank in the form of a thin wire, the diameter of the thin wire was 9.5 mm, and the addition speed was 1.2 kg / min;

[0132] (3) The refiner and the aluminum alloy solution were cold-rolled, and an aluminum blank was obtained after cold rolling, and the thickness of the aluminum blank was 0.21 mm;

[0133] (4) The aluminum blank was annealed at a temperature of 300℃ for 25 min;

[0134] (5) The annealed aluminum material is subjected to foil rolling, and an aluminum foil with a thickness of 13 μm is obtained after the foil rolling. The aluminum foil comprises: Fe: 0.16%, Si: 0.06%, Cu: 0.03%; Ti: 0.02%, La: 0.02%, Ce: 0.02%, and the balance being aluminum and unavoidable impurities.

[0135] Example 102

[0136] Electromagnetic stirring is used before cold rolling of the refining agent and the aluminum alloy solution, and other steps are the same as those in Example 101.

[0137] The temperature of the electromagnetic stirring is 700°C, and the time is 60 min.

[0138] Example 103

[0139] Electromagnetic stirring is used before cold rolling of the refining agent and the aluminum alloy solution, and other steps are the same as those in Example 101.

[0140] The temperature of the electromagnetic stirring is 450°C, and the time is 41 min.

[0141] Example 104

[0142] Electromagnetic stirring is used before cold rolling of the refining agent and the aluminum alloy solution, and other steps are the same as those in Example 101.

[0143] The temperature of the electromagnetic stirring is 750°C, and the time is 65 min.

[0144] Example 105

[0145] Stage electromagnetic stirring is used before cold rolling of the refining agent and the aluminum alloy solution, and other steps are the same as those in Example 101.

[0146] The temperature of the first stage stirring is 500°C, and the time of the first stage stirring is 4 min;

[0147] The temperature of the second stage stirring is 600°C, and the time of the second stage stirring is 8 min;

[0148] The temperature of the third stage stirring is 700°C, and the time of the third stage stirring is 15 min;

[0149] The temperature of the fourth stage stirring is 700°C, and the time of the third stage stirring is 25 min.

[0150] Example 106

[0151] Al-Ti-B refining agent is selected instead of Al-Ti-B-rare earth refining agent, and other steps are the same as those in Example 101.

[0152] Table 3 Test results of tensile strength and elongation of aluminum foils

[0153] As can be seen from the tests in Table 3, compared with Example 106, the rare earth element-containing refiner added to the molten aluminum alloy solution in Example 101 can improve the strength and elongation of the aluminum foil.

[0154] In Examples 102 to 105, the electromagnetic stirring of the aluminum alloy solution can make the rare earth elements in the refiner be better absorbed by the elements in the aluminum alloy, and make the rare earth elements be more uniformly distributed in the aluminum foil, so as to ensure the purity and elongation of the aluminum foil.

[0155] Although some specific embodiments of the present application have been described in detail by examples, those skilled in the art should understand that the above examples are only for illustration, but not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. An aluminum foil, wherein, comprises the following components by mass percentage: Fe: 0.15%-0.20%, Si: 0.05%-0.10%, Cu: 0.02%-0.05%; Ti: 0.01%-0.03%, rare earth elements: 0.02-0.2%, the balance being Al and unavoidable impurities; The rare earth elements comprise at least one of La, Ce, Pr, Tb and Yb.

2. The aluminum foil according to claim 1, wherein, The rare earth elements comprise La.

3. The aluminum foil according to claim 1, wherein, The rare earth elements comprise La and Ce.

4. The aluminum foil of claim 1, wherein, The rare earth elements comprise La, Ce and Pr.

5. The aluminum foil of claim 1, wherein, The rare earth elements comprise La, Ce, Pr and Tb.

6. The aluminum foil of claim 1, wherein, The rare earth elements comprise La, Ce, Pr, Tb and Yb.

7. The aluminum foil of claim 3, wherein, The mass ratio of La and Ce is (0.5-2):

1.

8. The aluminum foil of claim 1, wherein, The aluminum foil further contains B, and the content of B is 0.01%-0.05%.

9. The aluminum foil of claim 1, wherein, The tensile strength of the aluminum foil ranges from 200 MPa to 220 MPa, and the elongation of the aluminum foil is greater than or equal to 4.0%.

10. A method of producing an aluminum foil, wherein, comprises: melting the aluminum-containing raw material, the iron-containing raw material, the silicon-containing raw material, the copper-containing raw material, the titanium-containing raw material and the optional rare earth raw material to obtain a first aluminum alloy liquid; adding a refining agent to the first aluminum alloy liquid to perform a refining treatment to obtain a second aluminum alloy liquid; rolling the second aluminum alloy liquid after cold rolling and annealing treatment to obtain the aluminum foil according to any one of claims 1-9.

11. The production method according to claim 10, wherein The melting treatment comprises electromagnetic stirring, the temperature of the electromagnetic stirring is 450-750℃, and the time of the electromagnetic stirring is 40-70min.

12. The method of making according to claim 11, wherein, The electromagnetic stirring comprises: performing first-stage stirring on the first aluminum alloy liquid, the temperature of the first-stage stirring is 450-550℃, and the time of the first-stage stirring is 3-5min; performing second-stage stirring on the first aluminum alloy liquid, the temperature of the second-stage stirring is 550-650℃, and the time of the second-stage stirring is 8-10min; performing third-stage stirring on the first aluminum alloy liquid, the temperature of the third-stage stirring is 650-750℃, and the time of the third-stage stirring is 10-20min; performing fourth-stage stirring on the first aluminum alloy liquid, the temperature of the fourth-stage stirring is 650-750℃, and the time of the third-stage stirring is 20-30min.

13. The method of making according to claim 10, wherein, The refining agent comprises at least one of Al-Ti-B-rare earth, LaB6 and Al-Ti-B-C-rare earth.

14. A pole piece, wherein, comprises a current collector (1) and an active material (2) coated on at least one side surface of the current collector (1); The current collector (1) is the aluminum foil according to any one of claims 1-9.

15. A battery, wherein, comprises the pole piece according to claim 14.

Images