3003 alloy aluminum foil and its preparation method, application and battery

Abstract

The application relates to a 3003 alloy aluminum foil and a preparation method, application and battery thereof. The preparation method comprises the following steps: sequentially performing first cold rolling treatment and complete recrystallization annealing on a 3003 aluminum alloy cast-rolled blank to obtain first annealed material; the temperature of the complete recrystallization annealing is 450 DEG C-520 DEG C, and the time is 5h-9h; sequentially performing second cold rolling treatment and first incomplete recrystallization annealing on the first annealed material to obtain second annealed material; the temperature of the first incomplete recrystallization annealing is 20 DEG C-60 DEG C lower than that of the complete recrystallization annealing; performing foil rolling on the second annealed material to obtain a pre-product; performing second incomplete recrystallization annealing on the pre-product; the temperature of the second incomplete recrystallization annealing is 150 DEG C-250 DEG C, and the time is 4h-8h. The above method adopts the cast-rolled blank with a specific composition to perform three times of annealing treatment under different conditions, so that the elongation of the aluminum foil is improved, the thermal conductivity of the aluminum foil is improved, and the stability of the battery is improved.

Description

Technical Field

[0001] This invention relates to the field of aluminum foil processing technology, and in particular to a 3003 alloy aluminum foil, its preparation method, application, and battery. Background Technology

[0002] With the development of new energy vehicles, the demand for lithium batteries has grown rapidly. As the positive electrode current collector material of mainstream lithium battery products, battery aluminum foil has been widely used, which has also triggered a sharp increase in market demand for aluminum foil.

[0003] Against the backdrop of the development of large-module and integrated new energy battery (cell) products, the application end has increasingly higher demands for batteries with "long range", "large capacity" and "high charge and discharge efficiency". At the same time, it also puts forward requirements for battery aluminum foil, an important supporting material for new energy batteries, to have higher elongation and lower impedance while maintaining a certain strength. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for preparing 3003 alloy aluminum foil, which produces 3003 alloy aluminum foil with high elongation and low impedance. Furthermore, a 3003 alloy aluminum foil and its application in batteries are also provided.

[0005] In a first aspect, this application provides a method for preparing 3003 alloy aluminum foil, comprising the following steps:

[0006] A first annealed material is obtained by sequentially subjecting a 3003 aluminum alloy cast-rolled billet to a first cold rolling process and a full recrystallization annealing process. The full recrystallization annealing temperature is 450℃~500℃, and the time is 5h~9h. The cast-rolled billet, by mass percentage, includes the following elemental composition: Mn: 1.1%~1.4%, Cu: 0.2%~0.3%, Ti: 0.01%~0.028%, Mg: 0~0.005%, the total content of Si and Fe is 0.1%~0.2%, and the balance is aluminum.

[0007] The first annealed material is subjected to a second cold rolling process and a first incomplete recrystallization annealing process to obtain a second annealed material; the temperature of the first incomplete recrystallization annealing process is 20°C to 60°C lower than the temperature of the complete recrystallization annealing process.

[0008] The second annealed material is subjected to foil rolling to obtain a pre-finished product;

[0009] The pre-finished product is subjected to a second incomplete recrystallization annealing; the annealing temperature of the second incomplete recrystallization annealing is 150℃~250℃, and the time is 4h~8h.

[0010] The above preparation method involves sequentially subjecting a 3003 alloy aluminum cast-rolled billet with a specific composition ratio to a first cold rolling process, a complete recrystallization annealing process, a second cold rolling process, and a first incomplete recrystallization annealing process, followed by foil rolling. After foil rolling, an incomplete recrystallization annealing process is then performed. By improving the composition of the cast-rolled billet and further synergizing the three-stage annealing process of one complete recrystallization annealing and two incomplete recrystallization annealing processes, the above preparation method significantly improves the elongation of the aluminum foil and reduces its impedance, further enhancing battery stability. Moreover, the 3003 alloy aluminum foil obtained by the above method has high flatness.

[0011] In some embodiments, the temperature of the first incomplete recrystallization annealing is 400°C to 450°C, and the time is 5h to 9h.

[0012] In some embodiments, the temperature of the second incomplete recrystallization annealing treatment is 200°C to 250°C, and the time is 4 hours to 7 hours; or,

[0013] The temperature for the second incomplete recrystallization annealing treatment is 150℃~180℃, and the time is 5h~8h.

[0014] In some embodiments, the annealing state of the second annealed material is H22 state or H24 state.

[0015] In some embodiments, the annealed state of the third annealed material obtained after the second incomplete recrystallization annealing is H26 or H28.

[0016] In some embodiments, the foil rolling process includes rolling the second annealed material in 3 to 4 passes sequentially.

[0017] In some embodiments, the first cold rolling process includes rolling the 3003 aluminum alloy cast-rolled billet in at least one pass, with each pass rolling at a rate of 400 m / min to 700 m / min; and / or,

[0018] The second cold rolling process includes rolling the first annealed material in at least two passes; wherein the processing rate of the first pass is 50%~60%, and the rolling speed is ≤350m / min.

[0019] In some embodiments, prior to the foil rolling process, a third cold rolling process is further included on the second annealed material;

[0020] The third cold rolling process includes rolling the second annealed material in one pass, with a processing rate of 50%~55% and a rolling speed ≤350m / min.

[0021] The second aspect of this application provides a 3003 alloy aluminum foil, which is prepared using the method provided in the first aspect.

[0022] In some embodiments, the thickness of the 3003 alloy aluminum foil is 0.01 mm to 0.02 mm.

[0023] The third aspect of this application provides an application of the above-mentioned 3003 alloy aluminum foil in the preparation of batteries.

[0024] The fourth aspect of this application provides a battery comprising the aforementioned 3003 alloy aluminum foil. Detailed Implementation

[0025] To facilitate understanding of the present invention, a more comprehensive description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. It should be understood that these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0027] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0028] The weights of the relevant components mentioned in the embodiments of this invention can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this invention is within the scope disclosed in the embodiments of this invention. Specifically, the weights mentioned in the embodiments of this invention can be well-known units of mass in the chemical industry, such as μg, mg, g, and kg.

[0029] In this application, the temperatures for complete recrystallization annealing, homogenization annealing, and incomplete recrystallization annealing all refer to the temperature of the material.

[0030] In one embodiment of this application, a method for preparing 3003 alloy aluminum foil is provided, comprising the following steps S10 to S40:

[0031] S10. The 3003 aluminum alloy cast-rolled billet is subjected to a first cold rolling treatment and a full recrystallization annealing to obtain the first annealed material. The temperature of the full recrystallization annealing is 450℃~500℃, and the holding time is 5h~9h. The cast-rolled billet, by mass percentage, includes the following elemental components: Mn: 1.1%~1.4%, Cu: 0.2%~0.3%, Ti: 0.01%~0.028%, Mg: 0~0.005%, the total content of Si and Fe is 0.1%~0.2%, and the balance is aluminum.

[0032] S20. The first annealed material is subjected to a second cold rolling process and a first incomplete recrystallization annealing process in sequence to obtain a second annealed material; the temperature of the first incomplete recrystallization annealing is 20℃~60℃ lower than the temperature of the complete recrystallization annealing.

[0033] S30. The second annealed material is subjected to foil rolling to obtain a pre-finished product.

[0034] S40. Perform a second incomplete recrystallization annealing on the pre-finished product; the annealing temperature for the second incomplete recrystallization annealing is 150℃~250℃, and the time is 4h~8h.

[0035] The above preparation method involves sequentially subjecting a 3003 alloy aluminum cast-rolled billet with a specific composition ratio to a first cold rolling process, a first full recrystallization annealing process, a second cold rolling process, and a first incomplete recrystallization annealing process, followed by foil rolling. After foil rolling, a second incomplete recrystallization annealing process is performed. By improving the composition of the cast-rolled billet and further synergizing the three-stage annealing process of one full recrystallization annealing and two incomplete recrystallization annealing processes, the above preparation method significantly improves the elongation of the aluminum foil and reduces its impedance; further enhancing battery stability; and the 3003 alloy aluminum foil obtained by the above method has high flatness.

[0036] Specifically, in terms of the composition of the cast-rolled billet, the 3003 alloy aluminum cast-rolled billet uses Mn as the first main element and Cu as the second main element, and strictly limits the content of harmful elements such as Ti and Mg. Through the synergistic effect between the element components in a specific ratio, a bicomponent reinforced and uniformly structured cast-rolled billet is obtained, which in turn provides a basis for the high strength and high elongation of the aluminum foil.

[0037] In terms of the preparation method, before foil rolling, the material undergoes a first cold rolling process, a complete recrystallization annealing process, a second cold rolling process, and a first incomplete recrystallization annealing process. Through cold rolling, the grains of the alloy material are flattened and elongated to form a fibrous structure. This structure increases the dislocation density of the material, thereby further improving the strength of the material. However, due to the presence of too many dislocations and dislocation slip entanglements within the material structure, defects such as interstitial cracks may occur. Through complete recrystallization annealing, point defects and line defects such as dislocations and dislocation entanglements can be directly transformed into part of the grains through recrystallization, thereby significantly reducing the number and size of such defects. After annealing, the material has significantly reduced or even eliminated such defects within the structure, reducing the conditions for crack propagation from the defect sites during tensile deformation, thereby significantly improving the elongation of the material.

[0038] Following the second cold rolling process, a first incomplete recrystallization annealing is performed. The temperature conditions of this first incomplete recrystallization annealing are further controlled to ensure the annealed material reaches the H22 or H24 state. This eliminates the processing texture and attraction caused by cold working, improving the material's elongation. Furthermore, this incomplete recrystallization annealing under these conditions achieves homogenization of the aluminum alloy, contributing to the uniformity of the alloy's composition distribution and thus improving the overall performance stability of the material. This improved overall performance stability makes it easier to obtain aluminum foil with higher flatness and better sheet shape in subsequent foil rolling processes.

[0039] Furthermore, incomplete recrystallization annealing after foil rolling can partially eliminate the residual stress of the hard aluminum foil, thereby further improving the elongation of the aluminum foil. In addition, the increased elongation of the aluminum foil can reduce the shear stress caused by thermal deformation between the cathode material and the current collector, reducing the risk of cathode material detachment, thus improving cell stability and extending battery life.

[0040] As an example, the temperature for full recrystallization annealing can be 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, or 520°C. Further, the temperature for full recrystallization annealing can be a range defined by any two of the above points as endpoints. Preferably, the temperature for full recrystallization annealing is 480°C to 500°C.

[0041] As an example, the time for complete recrystallization annealing can be 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, or 9h. Further, the time for complete recrystallization annealing can be a range of values ​​defined by any two of the above points as endpoints. Preferably, the time for complete recrystallization annealing is 7h to 9h.

[0042] As an example, the temperature for the second incomplete recrystallization annealing can be 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, or 250°C. Furthermore, the temperature for the second incomplete recrystallization annealing can be a range of values ​​defined by any two of the above point values ​​as endpoints.

[0043] As an example, the time for the second incomplete recrystallization annealing can be 4h, 5h, 6h, 7h, or 8h. Furthermore, the time for the second incomplete recrystallization annealing can be a range of values ​​formed by using any two of the above point values ​​as endpoints.

[0044] In some embodiments, the temperature of the second incomplete recrystallization annealing is 200°C to 250°C, and the time is 4h to 7h.

[0045] In some embodiments, the temperature of the second incomplete recrystallization annealing is 150°C to 180°C, and the time is 5 hours to 8 hours. Different second incomplete recrystallization annealing temperatures can yield aluminum foils with different hardnesses, and a suitable second incomplete recrystallization annealing temperature can be selected according to the different strength requirements of the aluminum foil.

[0046] In some embodiments, the temperature of the first incomplete recrystallization annealing is 400°C to 450°C. As an example, the temperature of the first incomplete recrystallization annealing can be 400°C, 410°C, 430°C, 440°C, or 450°C. Further, the temperature of the first incomplete recrystallization annealing can be a range of values ​​defined by any two of the above points as endpoints. Preferably, the temperature of the first incomplete recrystallization annealing is 410°C to 430°C.

[0047] In some embodiments, the time for the first incomplete recrystallization annealing is 4h to 7h. As an example, the time for the first incomplete recrystallization annealing can be 4h, 5h, 5.5h, 6h, 6.5h, or 7h. The time for the first incomplete recrystallization annealing can be a range of values ​​defined by any two of the above points as endpoints. Preferably, the time for the first incomplete recrystallization annealing is 5h to 7h.

[0048] In some embodiments, the annealed state of the first annealed material is H22 or H24. Under this annealing condition, while ensuring the basic requirement of tensile strength >220 MPa, the elongation can be stably increased from 2.0% to over 4.0%, thereby better adapting to the thermal expansion and contraction problem of the positive electrode material and battery aluminum foil caused by thermal shock from charging and discharging. The increase in elongation can partially release the stress at the bonding interface caused by thermal expansion and contraction, thereby improving the thermal stability of the cell.

[0049] In some embodiments, the annealed state of the third annealed material obtained after the second incomplete recrystallization annealing is H26 or H28. It can be understood that the third annealed material obtained after the second incomplete recrystallization annealing is 3003 alloy aluminum foil.

[0050] In some embodiments, the cast-rolled billet is a sheet material.

[0051] In some embodiments, the thickness of the cast-rolled billet is 5 mm to 10 mm.

[0052] In some embodiments, the processing rate of the first cold rolling treatment is 25% to 50%. Further, the processing rate of the first cold rolling treatment is 25% to 35%. The processing rate of the first cold rolling treatment = (plate thickness before the first cold rolling treatment - plate thickness after the first cold rolling treatment) / plate thickness before the first cold rolling treatment × 100%.

[0053] In some embodiments, the first cold rolling process includes rolling the 3003 aluminum alloy cast-rolled billet in at least one pass.

[0054] In some embodiments, during the first cold rolling process, the rolling speed per pass is 300 m / min to 750 m / min. Further, the rolling speed per pass is 300 m / min to 350 m / min.

[0055] In some embodiments, during the first cold rolling process, the temperature of the 3003 aluminum alloy cast-rolled billet is maintained at ≤60°C.

[0056] In some embodiments, the second cold rolling process includes the following steps:

[0057] The annealed material is rolled in at least two passes sequentially; the first pass has a processing rate of 50%–60% and a rolling speed ≤350 m / min. It can be understood that in the second cold rolling process, the first annealed material can be rolled in 2, 3, 4, or 5 passes sequentially. For example, in the second cold rolling process, the first annealed material is rolled in 5 passes sequentially, with a processing rate of 50%–60% and a rolling speed ≤350 m / min in the first pass. The processing rates in the subsequent second, third, fourth, and fifth passes can be the same as and different from those in the first pass.

[0058] In some embodiments, during the second cold rolling process, the first annealed material is rolled in five passes sequentially, with a processing rate of 40% to 60% from the second to the fifth pass, and a rolling speed ≤ 600 m / min. Further, the processing rate from the second to the fifth pass is 40% to 50%, and the rolling speed from the second to the fifth pass is 400 m / min to 600 m / min.

[0059] In some embodiments, during the second cold rolling process, the temperature of the first annealed material is maintained at ≤60°C.

[0060] In some embodiments, the first cold rolling process and the second cold rolling process are carried out under the protection of a first composite lubricating oil; the first composite lubricating oil contains a base oil, a composite additive, and lauric acid. The composite additive is a conventionally used composite additive containing alcohol and ester components. The base oil is also a conventionally used lubricating base oil. Further, in the first composite lubricating oil, the mass of the composite additive is 5.0% to 6.5% of the mass of the base oil; the acid value of the first composite lubricating oil is 0.25 mg KOH / g to 0.40 mg KOH / g. Even further, the base oil is selected from No. 100 or No. 105 base oil; the composite additive is a 12W composite additive.

[0061] In some embodiments, during the first and second cold rolling processes, the temperature of the composite lubricating oil is 40°C to 60°C.

[0062] In some embodiments, a third cold rolling process is further included before the foil rolling process. The second annealed material is subjected to the third cold rolling process after the first incomplete recrystallization treatment and before the foil rolling process.

[0063] In some embodiments, the third cold rolling process includes rolling the second annealed material in one pass.

[0064] In some embodiments, the processing rate during the third cold rolling process is 50% to 55%.

[0065] In some embodiments, during the third cold rolling process, the rolling rate is ≤350 m / min. Further, the rolling rate is 300 m / min to 350 m / min. The rolling rate of the first cold rolling pass after the controlled annealing treatment can be 350 m / min.

[0066] In some embodiments, before the first full recrystallization annealing treatment after the first cold rolling process, the material after the first cold rolling process is further subjected to a trimming step.

[0067] In some embodiments, after the second cold rolling process and before the first incomplete recrystallization annealing, a step of trimming the material after the second cold rolling process is included. Trimming can remove cracks and defects that occur during rolling, inhibit further crack propagation, and improve rolling safety.

[0068] In some embodiments, foil rolling includes rolling the second annealed material in 3 to 4 passes sequentially.

[0069] In some embodiments, foil rolling includes rolling the second annealed material in two to three passes in a roughing mill and an intermediate mill, and then rolling it in one pass in a finishing mill.

[0070] In some embodiments, when rolling is performed in the roughing mill, the processing rate is 40% to 50% and the rolling speed is ≤500 m / min. Further, when rolling is performed in the roughing mill, the processing rate is 46% and the rolling speed is 300 m / min to 500 m / min.

[0071] In some embodiments, when rolling is performed in an intermediate rolling mill, the processing rate is 40% to 55% and the rolling speed is ≤600 m / min. Further, when rolling is performed in an intermediate rolling mill, the processing rate is 43% to 50% and the rolling speed is 450 m / min to 600 m / min.

[0072] In some embodiments, when rolling is performed in the finishing mill, the processing rate is 40% to 50% and the rolling speed is ≤500 m / min. Further, when rolling is performed in the finishing mill, the processing rate is 43% to 47% and the rolling speed is 400 m / min to 450 m / min.

[0073] In some embodiments, foil rolling is performed under the protection of lubricating oil. Performing foil rolling under the protection of lubricating oil helps to maintain the continuous stability of rolling force and sheet shape.

[0074] In some embodiments, during the foil rolling process, the temperature of the lubricating oil is controlled to be 40°C to 60°C.

[0075] In some embodiments, rolling is carried out under the protection of a second composite lubricating oil during roughing and intermediate rolling mill operations.

[0076] In some embodiments, the second composite lubricating oil includes a base oil, a composite additive, and lauric acid; wherein the base oil is selected from No. 80 base oil or No. 85 base oil; the composite additive is W12 composite additive; the amount of composite additive added to the lubricating oil is 5.0% to 7.5% of the mass of the base oil, and the acid value of the lubricating oil is 0.15 mg KOH / g to 0.45 mg KOH / g.

[0077] In some embodiments, when rolling is performed in a finishing mill, the lubricating oil used contains a base oil and a composite additive; wherein the base oil is selected from No. 80 base oil or No. 85 base oil; the composite additive is W12 composite additive; and the amount of composite additive added to the lubricating oil is 6.0% to 8.0% of the mass of the base oil.

[0078] In one embodiment of this application, a 3003 alloy aluminum foil is provided, which is prepared by the above-described preparation method.

[0079] In some embodiments, the thickness of the 3003 alloy aluminum foil is 0.01 mm to 0.020 mm. Further, the thickness of the 3003 alloy aluminum foil is 0.012 mm to 0.020 mm.

[0080] In some embodiments, the tensile strength of the 3003 alloy aluminum foil is 220 MPa to 260 MPa.

[0081] In some embodiments, the elongation of the 3003 alloy aluminum foil is 4.0% to 6.0%.

[0082] In some embodiments, the thermal conductivity of the 3003 alloy aluminum foil is >131 W / (m·K). Further, the thermal conductivity of the 3003 alloy aluminum foil is 160 W / (m·K) to 170 W / (m·K).

[0083] In one embodiment of this application, the above-mentioned 3003 alloy aluminum foil is provided for use in the preparation of batteries.

[0084] In one embodiment of this application, a battery is provided, which includes the aforementioned 3003 alloy aluminum foil.

[0085] In some embodiments, the battery includes an electrode. Preferably, the electrode is a positive electrode.

[0086] In some embodiments, the electrode sheet comprises the aforementioned 3003 alloy aluminum foil.

[0087] To make the objectives, technical solutions, and advantages of this invention clearer and more concise, the invention is described using the following specific embodiments, but the invention is by no means limited to these embodiments. The embodiments described below are merely preferred embodiments of the invention and can be used to describe the invention, but should not be construed as limiting the scope of the invention. It should be noted that any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the protection scope of this invention.

[0088] To better illustrate the present invention, the following embodiments are provided for further explanation. The specific embodiments are as follows.

[0089] Example 1

[0090] This embodiment prepares a battery aluminum foil with specifications of 0.012 / 0.013×1380×C H26 (i.e., the thickness of the battery aluminum foil product is 0.012~0.013mm, the width is 1380mm, C refers to the length of the aluminum coil, which is not limited in this embodiment, and the finished product state is H18).

[0091] 1. Provide cast and rolled billets: billet thickness is 6.8±0.015mm, billet width is 1460mm; by mass percentage, the chemical composition of the billet includes: Mn: 1.3±0.03%, Cu: 0.2±0.02%, Ti: 0.022%, Mg: 0.002%, total Fe and Si: 0.152%, other essential impurity elements: 0.10%, and balance aluminum.

[0092] 2. Cold rolling

[0093] (1) Prepare cold rolling lubricating oil: Mix No. 100 base oil and W12 composite additive in a mass ratio of 100: (5.0~7.0), then add lauric acid to adjust the acid value of the rolling lubricating oil to 0.25mgKOH / g~0.40mgKOH / g.

[0094] In this embodiment, cold rolling is performed using a cold rolling mill, and the rolling is carried out under the protection of the rolling lubricating oil configured above.

[0095] (2) First cold rolling process: The rolling lubricating oil obtained in step (1) is poured into the cold rolling mill to cold roll the cast-rolled coil. The cold rolling process is as follows: the cast-rolled billet is placed in the cold rolling mill to perform the first pass of rolling. The processing rate is 30±2% and the rolling speed is 300 m / min; the blank is obtained.

[0096] (3) Complete recrystallization annealing: The billet was subjected to complete recrystallization annealing at a temperature of 480℃ and an annealing time of 8h to obtain the first annealed material.

[0097] (4) Second cold rolling process: After the temperature of the first annealed material is ≤60℃, the first rolling process is carried out with a processing rate of 55±1% and a rolling speed of 300m / min; then the second rolling process is carried out with a processing rate of 45±1% and a rolling speed of 550m / min. Then the first edge trimming is carried out to obtain a cold-rolled aluminum coil with a thickness of 1.2±0.2mm.

[0098] Then, two more passes of cold rolling are performed, with a single pass cold rolling rate of 45%~48% and a rolling speed of 500m / min~700m / min; resulting in a cold-rolled coil with a thickness of 0.32mm.

[0099] (5) Second trimming + first incomplete recrystallization annealing: The cold-rolled coil with a thickness of 0.32 mm obtained in step (4) is transferred to a rewinding machine for second trimming; after the second trimming is completed, the first incomplete recrystallization annealing is performed at a temperature of 420℃ for 6 hours; the second annealed material is obtained.

[0100] (6) Third cold rolling treatment: The second annealed material is then subjected to one pass of cold rolling, with a processing rate of 55±1% and a rolling speed of 350m / min.

[0101] 3. Foil rolling

[0102] (1) Preparation of foil rolling lubricating oil: Mix No. 80 base oil and W12 composite additive in a mass ratio of 100:7, then add lauric acid to adjust the acid value of the mixed oil to 0.25mgKOH / g to obtain foil rolling lubricating oil 1.

[0103] The No. 80 base oil and W12 composite additive were mixed at a mass ratio of 100:7.5 to obtain foil rolling lubricating oil 2.

[0104] (2) Rough rolling of aluminum foil: Lubricating oil 1 for foil rolling is poured into the rough rolling mill and intermediate rolling mill. Then, the annealed material after the third cold rolling treatment is placed in the rough rolling mill and rolled in one pass with a processing rate of 45±2% and a rolling speed of 500m / min. Then, it is rolled in one pass in the intermediate rolling mill with a processing rate of 45±2% and a rolling speed of 600m / min to obtain aluminum foil coils.

[0105] (3) Finished product rolling: Pour foil rolling lubricating oil 2 into the finishing mill; roll the aluminum foil coil obtained in step (2) in the finishing mill for one pass, with a processing rate of 45±1.5% and a rolling speed of 400m / min; and obtain aluminum foil with a thickness of 0.012mm~0.013mm.

[0106] (4) Second incomplete recrystallization annealing: The aluminum foil obtained in step (3) is annealed in H26 state at a temperature of 220°C for 6 hours to obtain the finished aluminum foil.

[0107] Example 2

[0108] The preparation method of this embodiment is basically the same as that of Example 1, except that the conditions for incomplete recrystallization annealing are different. Specifically, the second incomplete recrystallization annealing step in this embodiment is as follows: the aluminum foil obtained from the finished product rolling step is annealed in the H28 state at a temperature of 160°C for 8 hours to obtain the finished aluminum foil.

[0109] Example 3

[0110] The preparation method in this embodiment is basically the same as that in Example 1, except that the conditions for the second incomplete crystallization annealing are different. Specifically, the second incomplete crystallization annealing temperature in this embodiment is 240°C, and the holding time is 4 hours.

[0111] Example 4

[0112] The preparation method in this embodiment is basically the same as that in Example 1, except that the conditions for the second incomplete crystallization annealing are different. Specifically, the second incomplete crystallization annealing temperature in this embodiment is 180°C, and the holding time is 5 hours.

[0113] Comparative Example 1

[0114] The preparation method of this comparative example is basically the same as that of Example 1, except that the second incomplete recrystallization step is omitted in the foil rolling process of this comparative example.

[0115] Comparative Example 2

[0116] The preparation method of this comparative example is basically the same as that of Example 1, except that the elemental composition of the 3003 alloy aluminum cast-rolled billet is different. The 3003 alloy aluminum cast-rolled billet of this comparative example, by mass percentage, includes: Mn: 1.0%, Cu: 0.06%, Ti: 0.018%, Mg: 0.008%, Fe and Si total: 0.122%, other essential impurity elements: 0.08%, and balance aluminum.

[0117] The annealing parameters for each embodiment and comparative example are shown in Table 1.

[0118] Performance testing

[0119] The tensile strength and elongation of the aluminum foils prepared in each embodiment and comparative example were tested according to the method specified in GB / T 22638.11-2023.

[0120] The thermal conductivity of the finished aluminum foils prepared in each embodiment and comparative example was tested using the method specified in JG / T 425-2019.

[0121] The performance test data of the 3003 alloy aluminum foil prepared in the examples and comparative examples are shown in Table 1 below.

[0122] Table 1

[0123]

[0124] Table 2

[0125]

[0126] As can be seen from Table 1, when aluminum foil was prepared using the preparation method of this application in Examples 1 to 4, the resulting aluminum foil had a tensile strength of 220 MPa to 290 MPa, an elongation of 4.0% to 6.0%, and a thermal conductivity of 162 W / (m·K) to 168 W / (m·K).

[0127] Comparative Example 1 used a preparation method basically the same as Example 1, except that it did not undergo a second incomplete recrystallization annealing treatment. The resulting aluminum foil had a tensile strength of 310 MPa, an elongation of 2.0%, and a thermal conductivity of 152 W / (m·K). This may be because Cu increases both strength and thermal conductivity, but because it did not undergo final annealing (i.e., the second incomplete annealing), the elongation was comparable to that of typical battery aluminum foil.

[0128] The elemental composition of the cast-rolled billet provided in Comparative Example 2 is different from that in Example 1. The aluminum foil prepared in Comparative Example 2 has a tensile strength of 205 MPa, an elongation of 4.5%, and a thermal conductivity of 146 W / (m·K). This may be because the Cu content is too low, and the Cu element fails to play a sufficient strengthening role. This makes the aluminum foil fall into the category of "low-strength aluminum foil" in battery aluminum foil strength.

[0129] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0130] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing 3003 alloy aluminum foil, characterized in that, Includes the following steps: A first annealed material is obtained by sequentially subjecting a 3003 aluminum alloy cast-rolled billet to a first cold rolling process and a full recrystallization annealing process. The full recrystallization annealing temperature is 450℃~520℃, and the time is 5h~9h. The cast-rolled billet, by mass percentage, includes the following elemental composition: Mn: 1.1%~1.4%, Cu: 0.2%~0.3%, Ti: 0.01%~0.028%, Mg: 0~0.005%, Si and Fe total content of 0.1%~0.2%, and the balance aluminum. The first annealed material is subjected to a second cold rolling process and a first incomplete recrystallization annealing process to obtain a second annealed material; the temperature of the first incomplete recrystallization annealing process is 20°C to 60°C lower than the temperature of the complete recrystallization annealing process. The second annealed material is subjected to foil rolling to obtain a pre-finished product; The pre-finished product is subjected to a second incomplete recrystallization annealing; the temperature of the second incomplete recrystallization annealing is 150℃~250℃, and the time is 4h~8h.

2. The preparation method according to claim 1, characterized in that, The temperature for the first incomplete recrystallization annealing is 400℃~450℃, and the time is 5h~9h.

3. The preparation method according to claim 1, characterized in that, The second incomplete recrystallization annealing treatment is performed at a temperature of 200℃~250℃ for 4h~7h; or, The temperature for the second incomplete recrystallization annealing treatment is 150℃~180℃, and the time is 5h~8h.

4. The preparation method according to claim 1, characterized in that, The annealing state of the second annealed material is either H22 state or H24 state.

5. The preparation method according to claim 1, characterized in that, The annealed state of the third annealed material obtained after the second incomplete recrystallization annealing is H26 or H28.

6. The preparation method according to any one of claims 1 to 5, characterized in that, The foil rolling process includes rolling the second annealed material in 3 to 4 passes.

7. The preparation method according to any one of claims 1 to 5, characterized in that, The first cold rolling process includes rolling the 3003 aluminum alloy cast-rolled billet in at least one pass, with each pass rolling at a rate of 300 m / min to 700 m / min; and / or, The second cold rolling process includes rolling the first annealed material in at least two passes; wherein the processing rate of the first pass is 50%~60%, and the rolling speed is ≤350m / min.

8. The preparation method according to any one of claims 1 to 5, characterized in that, Prior to the foil rolling process, a third cold rolling process is also included for the second annealed material. The third cold rolling process includes rolling the second annealed material in one pass, with a processing rate of 50%~55% and a rolling speed ≤350m / min.

9. A 3003 alloy aluminum foil, characterized in that, The aluminum foil is prepared by the method described in any one of claims 1 to 8.

10. The 3003 alloy aluminum foil as described in claim 9, characterized in that, The thickness of the 3003 alloy aluminum foil is 0.01mm to 0.020mm.

11. The application of the 3003 alloy aluminum foil as described in any one of claims 9 to 10 in the preparation of batteries.

12. A battery, characterized in that, Includes the 3003 alloy aluminum foil as described in any one of claims 9 to 10.

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