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 of the 3003 alloy aluminum foil comprises the following steps: sequentially performing first cold rolling treatment and first complete recrystallization annealing treatment on a cast-rolled blank to obtain first annealed material; sequentially performing second cold rolling treatment and second complete recrystallization annealing treatment on the first annealed material to obtain second annealed material; and performing foil rolling on the second annealed material; the temperature of the first complete recrystallization annealing treatment is 430 DEG C-500 DEG C, and the holding time is 5h-9h; the temperature of the second complete recrystallization annealing treatment is 410 DEG C-485 DEG C, and the holding time is 4h-8h. The above method can reduce the pass rolling number in the foil rolling process, improve the elongation of the aluminum foil, and further improve the finished product rate of the battery aluminum foil product processing by adopting the cast-rolled blank with a specific composition to perform twice annealing treatment.

Description

Technical Field

[0001] This application 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] Traditional battery aluminum foil processing involves both cold rolling and foil rolling, with the foil rolling process requiring at least five rolling passes. However, excessive rolling passes significantly reduce the plasticity and toughness of the aluminum foil, making it prone to cracking and even breakage during subsequent processing. This significantly reduces the yield of battery aluminum foil products. Furthermore, too many rolling passes increase production time and reduce efficiency, thereby increasing production costs for companies. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for preparing 3003 alloy aluminum foil, which yields 3003 alloy aluminum foil with high elongation; furthermore, a 3003 alloy aluminum foil and its application in batteries are provided.

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

[0006] The first annealed material was obtained by sequentially subjecting the 3003 alloy aluminum cast-rolled billet to a first cold rolling process and a first full recrystallization annealing process.

[0007] The first annealed material is subjected to a second cold rolling process and a second full recrystallization annealing process in sequence to obtain a second annealed material.

[0008] The second annealed material is then subjected to foil rolling;

[0009] The temperature of the first complete recrystallization annealing treatment is 430℃~500℃, and the holding time is 5h~9h;

[0010] The temperature for the second complete recrystallization annealing treatment is 410℃~485℃, and the holding time is 4h~8h;

[0011] The cast-rolled billet, by mass percentage, comprises the following elemental components: 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 balance aluminum.

[0012] 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 second full recrystallization annealing process, followed by foil rolling. In the cast-rolled billet composition, Mn is used as the first main element and Cu as the second main element, while the contents of harmful elements Ti and Mg are strictly limited. Through the synergistic effect of the specific elemental composition ratios, a bicomponent reinforced cast-rolled billet with low impedance characteristics and a uniform microstructure is obtained. In the preparation method, before foil rolling, the billet undergoes two cold rolling processes and two full recrystallization annealing processes. The temperature and time of the two full recrystallization annealing processes are further controlled to ensure that the annealed material with the specific composition ratio reaches the 0-state. This 0-state annealed material has lower hardness and higher plasticity, making it easier to perform foil rolling and requiring fewer rolling passes, thus reducing the process risks associated with multi-pass rolling. Simultaneously, it improves the elongation of the aluminum foil and further increases the yield of aluminum foil-related products. In addition, the increased elongation of aluminum foil can reduce the shear stress caused by thermal deformation between the cathode material and the current collector, reduce the risk of cathode material falling off, thereby improving cell stability and extending battery life.

[0013] In some embodiments, the temperature of the first full recrystallization annealing treatment is 15°C to 20°C higher than the temperature of the second full recrystallization annealing treatment.

[0014] In some embodiments, the processing rate of the first cold rolling process is 30% to 55%; and / or, the processing rate of the second cold rolling process is 35% to 58%.

[0015] In some embodiments, the second cold rolling process includes the following steps:

[0016] The first annealed material is rolled in at least two passes; wherein the processing rate of the first pass is 50%~60% and the rolling speed is ≤350m / min.

[0017] In some embodiments, the foil rolling process includes rolling the second annealed material once in each of the roughing mill, the intermediate mill, and the finishing mill.

[0018] In some embodiments, when rolling is performed in the roughing mill, the processing rate is 50%~60% and the rolling speed is ≤300m / min; and / or,

[0019] When rolling is performed in the intermediate rolling mill, the processing rate is 45%~55%, and the rolling speed is ≤600m / min; and / or,

[0020] When rolling is carried out in the finishing mill, the processing rate is 45%~50% and the rolling speed is ≤500m / min.

[0021] In some embodiments, the 3003 alloy aluminum cast-rolled billet is a plate, and the thickness of the 3003 alloy aluminum cast-rolled billet is 5mm~8mm.

[0022] The second aspect of this application provides a 3003 alloy aluminum foil, which is prepared using the method provided in the first aspect.

[0023] In some embodiments, the thickness of the 3003 alloy aluminum foil is 0.01 mm to 0.02 mm.

[0024] The third aspect of this application provides an application of the above-mentioned 3003 alloy aluminum foil in the preparation of batteries.

[0025] The fourth aspect of this application provides a battery comprising the aforementioned 3003 alloy aluminum foil. Detailed Implementation

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] In one embodiment of this application, a method for preparing 3003 alloy aluminum foil is provided, comprising the following steps S10~S30:

[0031] S10. The 3003 alloy aluminum cast-rolled billet is subjected to a first cold rolling treatment and a first full recrystallization annealing treatment in sequence to obtain the first annealed material; the temperature of the first full recrystallization annealing treatment is 430℃~500℃, and the holding time is 5h~9h.

[0032] S20. The first annealed material is subjected to a second cold rolling treatment and a second full recrystallization annealing treatment in sequence to obtain a second annealed material; the temperature of the second full recrystallization annealing treatment is 410℃~485℃, and the holding time is 4h~8h.

[0033] S30. The second annealed material is foil rolled.

[0034] The above-mentioned 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%, Si and Fe total content of 0.1%~0.2%, and balance aluminum.

[0035] The temperatures of the first and second complete recrystallization annealing treatments mentioned above both refer to the temperature of the material.

[0036] 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 second full recrystallization annealing process, followed by foil rolling. In the cast-rolled billet composition, Mn is used as the first main element and Cu as the second main element, while the contents of harmful elements Ti and Mg are strictly limited. Through the synergistic effect of the specific elemental composition ratios, a bicomponent reinforced cast-rolled billet with low impedance characteristics and a uniform microstructure is obtained. In the preparation method, before foil rolling, the billet undergoes two cold rolling processes and two full recrystallization annealing processes. The temperature and time of the two full recrystallization annealing processes are further controlled to ensure that the annealed material with the specific composition ratio reaches the 0-state. This 0-state annealed material has lower hardness and higher plasticity, making it easier to perform foil rolling and requiring fewer rolling passes, thus reducing the process risks associated with multi-pass rolling. Simultaneously, it improves the elongation of the aluminum foil and further increases the yield of aluminum foil-related products. In addition, the increased elongation of aluminum foil can reduce the shear stress caused by thermal deformation between the cathode material and the current collector, reduce the risk of cathode material falling off, thereby improving cell stability and extending battery life.

[0037] As an example, the temperature for the first complete recrystallization annealing can be 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, or 500°C. Further, the temperature for the first complete recrystallization annealing can be a range of values ​​defined by any two of the above points as endpoints. Preferably, the temperature for the first complete recrystallization annealing is 480°C to 500°C.

[0038] As an example, the time for the first complete recrystallization annealing can be 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, or 9h. The time for the first complete recrystallization annealing can be a range of values ​​formed by using any two of the above points as endpoints. Preferably, the time for the first complete recrystallization annealing is 6h to 9h.

[0039] As an example, the temperature of the second annealing can be 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, or 485°C. Further, the temperature of the second complete recrystallization annealing can be a range of values ​​defined by any two of the above points as endpoints. Preferably, the temperature of the second complete recrystallization annealing is 420°C to 450°C.

[0040] As an example, the time for the second complete recrystallization annealing can be 4h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, or 8h. The time for the second complete recrystallization annealing can be a range of values ​​defined by any two of the above points as endpoints. Preferably, the time for the second complete recrystallization annealing is 5h to 8h.

[0041] In some embodiments, the temperature of the first full recrystallization annealing treatment is 15°C to 20°C higher than the temperature of the second full recrystallization annealing treatment.

[0042] In some embodiments, the cast-rolled billet is a sheet material.

[0043] In some embodiments, the thickness of the cast-rolled billet is 5 mm to 8 mm.

[0044] In some embodiments, the processing rate of the first cold rolling treatment is 35% to 55%. The processing rate of the first cold rolling treatment = (thickness of the sheet before the first cold rolling treatment - thickness of the sheet after the first cold rolling treatment) / thickness of the sheet before the first cold rolling treatment × 100%. As an example, the processing rate of the first cold rolling treatment can be 35%, 40%, 43%, 45%, 50%, or 55%.

[0045] In some embodiments, the first cold rolling process includes: rolling the 3003 aluminum alloy cast-rolled billet in 1-2 passes; the processing rate of each pass is 35%-40%; and the rolling speed of each pass is 250m / min-400m / min. The processing rate of each pass = (thickness of the sheet before each pass - thickness of the sheet after each pass) / thickness of the sheet before each pass × 100%. Preferably, the first cold rolling process involves rolling the 3003 aluminum alloy cast-rolled billet in 1 pass.

[0046] In some embodiments, during the first cold rolling process, the temperature of the 3003 aluminum alloy cast-rolled billet is maintained at ≤60°C.

[0047] In some embodiments, the processing rate of the second cold rolling process is 35% to 58%. The processing rate of the second cold rolling process is calculated as: (thickness of the sheet before the first cold rolling process - thickness of the sheet after the second cold rolling process) / thickness of the sheet before the second cold rolling process × 100%. As an example, the processing rate of the second cold rolling process can be 35%, 40%, 45%, 50%, 55%, or 58%. Further, the processing rate of the second cold rolling process can be 45% to 58%.

[0048] In some embodiments, the second cold rolling process includes the following steps:

[0049] The first annealed material is rolled in at least two passes; wherein the processing rate of the first pass is 50%~60%, and the rolling speed is ≤350m / min. Further, the rolling speed is 250m / min~350m / min.

[0050] It is understood that in the second cold rolling process, the first annealed material can be rolled in 2 passes, 3 passes, 4 passes, or 5 passes sequentially. As an example, in the second cold rolling process, the first annealed material is rolled in 5 passes sequentially; wherein, in the first pass, the processing rate is 50%~60%, and the rolling speed is ≤350m / min; while in the subsequent second, third, fourth, and fifth passes, the processing rate and rolling speed can be the same as the first pass, or they can be different from the first pass.

[0051] In some embodiments, during the second cold rolling process, the first annealed material is rolled in five passes sequentially, with the processing rate from the second to the fifth pass each being 45% to 60%, and the rolling speed from the second to the fifth pass each being ≤600 m / min. Further, the rolling speed from the second to the fifth pass each is 450 m / min to 550 m / min.

[0052] 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 composite additive containing alcohol and ester components commonly used in the art. The base oil is also a lubricating base oil commonly used in the art.

[0053] Furthermore, 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.

[0054] In some embodiments, after the first cold rolling process and before the first full recrystallization annealing process, a step of trimming the cold-rolled material is included. Trimming removes cracks that occur during rolling, inhibits further crack propagation, and improves rolling safety.

[0055] In some embodiments, after the second cold rolling process is completed and before the second full recrystallization annealing process, the step of trimming the material after the second rolling process is further included.

[0056] In some embodiments, foil rolling includes sequentially rolling the second annealed material once in a roughing mill, once in an intermediate mill, and once in a finishing mill. The roughing mill, intermediate mill, and finishing mill are conventional rolling mills used in foil rolling processes in this field.

[0057] In some embodiments, when rolling is performed in the roughing mill, the processing rate is 50% to 60% and the rolling speed is ≤300 m / min. Further, when rolling is performed in the roughing mill, the processing rate is 53% to 58% and the rolling speed is 250% to 300 m / min.

[0058] In some embodiments, when rolling is performed in an aluminum foil rolling mill, the processing rate is 45% to 55% and the rolling speed is ≤600 m / min. Further, when rolling is performed in an intermediate rolling mill, the processing rate is 48% to 52% and the rolling speed is 400 m / min to 600 m / min.

[0059] 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 40% to 45% and the rolling speed is 400 m / min to 500 m / min.

[0060] In some embodiments, foil rolling is performed under the protection of lubricating oil. Performing foil rolling under the protection of lubricating oil is beneficial for obtaining a stable sheet shape and a clean surface.

[0061] In some embodiments, rolling is carried out under the protection of a second composite lubricating oil during roughing and intermediate rolling mill operations.

[0062] 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 6.0% 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 0.25 mg KOH / g.

[0063] In some embodiments, rolling is performed in a finishing mill under the protection of a third composite lubricating oil.

[0064] In some embodiments, the third compound lubricating oil contains a base oil and a compound additive; wherein the base oil is selected from No. 80 base oil or No. 85 base oil; the compound additive is a W12 compound additive; and the amount of the compound additive added to the lubricating oil is 6.5% to 8.0% of the mass of the base oil.

[0065] In one embodiment of this application, a 3003 alloy aluminum foil is provided, which is prepared by the above-described preparation method.

[0066] In some embodiments, the thickness of the 3003 alloy aluminum foil is 0.01 mm to 0.02 mm. As an example, the thickness of the 3003 alloy aluminum foil can be 0.01 mm, 0.011 mm, 0.012 mm, 0.013 mm, 0.014 mm, 0.015 mm, 0.016 mm, 0.017 mm, 0.018 mm, 0.019 mm, or 0.02 mm. Further, the thickness of the 3003 alloy aluminum foil can be a range of values ​​defined by any two of the above point values ​​as endpoints.

[0067] In some embodiments, the tensile strength of the 3003 alloy aluminum foil is 220 MPa to 260 MPa.

[0068] In some embodiments, the elongation of the 3003 alloy aluminum foil is 4.5% to 6.5%.

[0069] In some embodiments, the thermal conductivity of 3003 alloy aluminum foil is 160 W / (m·K) to 168 W / (m·K).

[0070] In one embodiment of this application, the above-mentioned 3003 alloy aluminum foil is provided for use in the preparation of batteries.

[0071] In one embodiment of this application, a battery is provided, which includes the aforementioned 3003 alloy aluminum foil.

[0072] In some embodiments, the battery includes an electrode. Preferably, the electrode is a positive electrode.

[0073] In some embodiments, the electrode sheet comprises the aforementioned 3003 alloy aluminum foil.

[0074] 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.

[0075] To better illustrate the present invention, the following embodiments are provided for further explanation. The specific embodiments are as follows.

[0076] Example 1

[0077] This embodiment prepares a battery aluminum foil with specifications of 0.013×1380×C H18 (i.e., the thickness of the battery aluminum foil is 0.012~0.013mm, the width is 1380mm, and C refers to the length of the aluminum coil, which is not limited in this embodiment, and the finished product is in the state of H18).

[0078] 1. Provide cast and rolled billets: billet thickness is 6.4±0.015mm, billet width is 1460mm; by mass percentage, the chemical composition of the billet includes: Mn: 1.22%, Cu: 0.221%, Ti: 0.025%, Mg: 0.002%, total Fe and Si: 0.155%, other essential impurity elements: 0.10%, and balance aluminum.

[0079] Other requirements: Width, thickness variation, wedge shape, and convexity shall be in accordance with the general standards for battery aluminum foil blanks.

[0080] 2. Cold rolling

[0081] (1) Preparation of cold rolling lubricating oil: Mix No. 100 base oil and W12 composite additive in a mass ratio of 100:6.5, then add lauric acid to adjust the acid value of the cold rolling lubricating oil to 0.30 mgKOH / g.

[0082] This embodiment uses a cold rolling mill for cold rolling, and the rolling is carried out under the protection of the cold rolling lubricating oil configured above.

[0083] (2) First cold rolling process: The cold 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 40%~43%, and the rolling speed is 300 m / min; the blank is obtained.

[0084] (3) First full recrystallization annealing treatment: The billet was subjected to the first full recrystallization annealing at a temperature of 460℃ and a holding time of 5h to obtain the first annealed material.

[0085] (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±2% and a rolling speed of 300m / min; then the second rolling process is carried out with a processing rate of 50±2% and a rolling speed of 500m / min. Then the first edge trimming is carried out to obtain the first cold-rolled coil with a thickness of 0.8±0.2mm.

[0086] Then, two more cold rolling passes are performed, with a processing rate of 47±2% for each pass and a rolling speed of 600m / min, to obtain a second cold-rolled coil with a thickness of 0.22mm.

[0087] (5) Second trimming + second full recrystallization annealing: The second cold-rolled coil with a thickness of 0.22 mm obtained in step (4) is transferred to a rewinding machine for second trimming; after the second trimming, a single cold rolling process is performed with a processing rate of 50±2% and a rolling speed of 600 m / min. Then, a second full recrystallization annealing process is performed with an annealing temperature of 440℃ and a time of 5 h to obtain the second annealed material.

[0088] 3. Foil rolling

[0089] (1) Preparation of foil rolling lubricating oil: Mix No. 80 base oil and W12 composite additive in a mass ratio of 100:7.0, then add lauric acid to adjust the acid value of the mixed oil to 0.20 mg KOH / g to obtain foil rolling lubricating oil 1.

[0090] 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.

[0091] (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 second annealed material is placed in the rough rolling mill and rolled in one pass with a processing rate of 55±2% and a rolling speed of 300m / min. Then, it is rolled in one pass in the intermediate rolling mill with a processing rate of 50±2% and a rolling speed of 400m / min to obtain aluminum foil coils.

[0092] (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±2% and a rolling speed of 500m / min; and obtain finished aluminum foil with a thickness of 0.013mm.

[0093] Example 2

[0094] This embodiment prepares a battery aluminum foil with specifications of 0.012×1050×C H18 (i.e., the thickness of the battery aluminum foil product is 0.012mm, the width is 1050mm, C refers to the length of the aluminum coil, and the finished product state is H18).

[0095] 1. Provide cast and rolled billets: billet thickness is 6.4±0.015mm, billet width is 1120mm; by mass percentage, the chemical composition of the billet includes: Mn: 1.35%, Cu: 0.205%, Ti: 0.028%, Mg: 0.003%, total Fe and Si: 0.16%, other essential impurity elements: 0.10%, and balance aluminum.

[0096] Other requirements: Width, thickness variation, wedge shape, and convexity shall be in accordance with the general standards for battery aluminum foil.

[0097] 2. Cold rolling

[0098] (1) Preparation of cold rolling lubricating oil: Mix No. 105 base oil and W12 composite additive in a mass ratio of 100:7.0, then add lauric acid to adjust the acid value of the cold rolling lubricating oil to 0.30 mgKOH / g.

[0099] 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.

[0100] (2) First cold rolling process: The cold 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 40%~42%, and the rolling speed is 300 m / min; the blank is obtained.

[0101] (3) First full recrystallization annealing treatment: The billet is subjected to the first full recrystallization annealing at a temperature of 480℃ and a holding time of 8h to obtain the first annealed material.

[0102] (4) Second cold rolling process: After the temperature of the first annealed material is ≤35℃, the first rolling process is carried out with a processing rate of 55±3% and a rolling speed of 300m / min; then the second rolling process is carried out with a processing rate of 50±3% and a rolling speed of 500m / min. Then the first edge trimming is carried out to obtain the first cold-rolled coil with a thickness of 0.9±0.2mm.

[0103] Then, two more cold rolling passes are performed, with a processing rate of 45% for each pass and a rolling speed of 600 m / min, to obtain a second cold-rolled coil with a thickness of 0.23 mm.

[0104] (5) Second trimming + second full recrystallization annealing: The second cold-rolled coil with a thickness of 0.23 mm obtained in step (4) is transferred to a rewinding machine for a second trimming; after the second trimming, a single cold rolling process is performed with a processing rate of 50±2% and a rolling speed of 600 m / min. Then, a second full recrystallization annealing process is performed with an annealing temperature of 440℃ and a time of 6 h; the second annealed material is obtained.

[0105] 3. Foil rolling

[0106] (1) Preparation of foil rolling lubricating oil: Mix No. 80 base oil and W12 composite additive in a mass ratio of 100:7.0, then add lauric acid to adjust the acid value of the mixed oil to 0.20 mgKOH / g to obtain foil rolling lubricating oil 1.

[0107] 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.

[0108] (2) Rough rolling of aluminum foil: The foil rolling lubricating oil 1 is poured into the aluminum foil rough rolling mill and the intermediate rolling mill respectively. Then the second annealed material is placed in the aluminum foil rough rolling mill and rolled in one pass with a processing rate of 55±3% and a rolling speed of 300m / min. Then it enters the intermediate rolling mill for one pass rolling with a processing rate of 50±3% and a rolling speed of 400m / min to obtain aluminum foil coil.

[0109] (3) Finished product rolling: Pour foil rolling lubricating oil 2 into the aluminum foil finishing mill; roll the aluminum foil roll obtained in step (2) in the aluminum foil finishing mill for one pass, with a processing rate of 46±2% and a rolling speed of 500m / min; and obtain finished aluminum foil with a thickness of 0.013mm.

[0110] Example 3

[0111] The preparation method in this embodiment is basically the same as that in Example 1, except that the annealing conditions for the first and second complete recrystallization annealing treatments are different. Specifically, the temperature of the first complete recrystallization annealing treatment in this embodiment is 480°C and the holding time is 8 hours; the annealing temperature of the second complete recrystallization annealing treatment is 440°C and the holding time is 6 hours.

[0112] Example 4

[0113] The preparation method of this embodiment is basically the same as that of Example 1. The only difference is that the annealing conditions of the first complete recrystallization annealing treatment and the second complete recrystallization annealing treatment are different. In this embodiment, the annealing temperature of the first complete recrystallization annealing treatment is 490°C and the holding time is 8h; the annealing temperature of the second complete recrystallization annealing treatment is 475°C and the holding time is 6h.

[0114] Comparative Example 1

[0115] The preparation method of this comparative example is basically the same as that of Example 1, except that the annealing conditions for the first and second complete recrystallization annealing treatments are different. Specifically, the annealing temperature for the first complete recrystallization annealing treatment in this comparative example is 460°C, and the holding time is 20 h; the annealing temperature for the second complete recrystallization annealing treatment is 440°C, and the holding time is 15 h.

[0116] Comparative Example 2

[0117] This comparative example prepares a battery aluminum foil with specifications of 0.12×1380×C H18 (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 example, and the finished product is H18):

[0118] 1. Provide cast-rolled billet: billet thickness is 6.4±0.015mm, billet width is 1460mm; by mass percentage, the chemical composition of the billet includes: Mn: 1.0%, Cu: 0.06%, Ti: 0.018%, Mg: 0.008%, total Fe and Si: 0.15%, other essential impurity elements: 0.03%, and balance aluminum.

[0119] 2. Cold rolling

[0120] (1) Prepare cold rolling lubricating oil: Mix No. 100 base oil and W12 composite additive in a mass ratio of 100:6.5, then add lauric acid to adjust the acid value of the cold rolling lubricating oil to 0.25mgKOH / g~0.40 mgKOH / g.

[0121] This comparative example uses a cold rolling mill for cold rolling, and the rolling is carried out under the protection of the rolling lubricating oil configured above.

[0122] (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 1850 cold rolling mill to perform the first pass rolling of the cast-rolled billet. The processing rate is 45% and the rolling speed is 350 m / min; the blank is obtained.

[0123] (3) First full recrystallization annealing treatment: The billet is subjected to the first full recrystallization annealing at a temperature of 480℃ and a holding time of 8h to obtain the first annealed material.

[0124] (4) Second cold rolling process: After the temperature of the first annealed material is ≤60℃, two rolling processes are carried out. The processing rate of the first rolling process after annealing is 55%, and the rolling speed is 350 m / min; the processing rate of the second rolling process is 45%, and the rolling speed is 550 m / min. Then the edges are trimmed, and a first cold rolled coil with a thickness of 1.1mm~1.5mm is obtained.

[0125] After trimming, the coil undergoes two more cold rolling passes, with a processing rate of 45% per pass and a rolling speed of 600 m / min. Then, the edges are trimmed to obtain a second cold-rolled coil with a thickness of 0.42 mm to 0.45 mm.

[0126] After the second trimming, the second cold-rolled aluminum coil is subjected to one cold rolling pass with a processing rate of 45% and a rolling speed of 600 m / min; a third cold-rolled coil with a thickness of 0.26 mm to 0.34 mm is obtained.

[0127] 3. Foil rolling

[0128] (1) Preparation of foil rolling lubricating oil: Mix No. 80 base oil and W12 composite additive in a mass ratio of 100:7.0, then add lauric acid to adjust the acid value of the mixed oil to 0.20 mgKOH / g to obtain foil rolling lubricating oil 1.

[0129] 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.

[0130] (2) Aluminum foil rough rolling: Pour foil rolling lubricating oil 1 into the aluminum foil rough rolling mill, and then place the third cold rolled coil in the aluminum foil rough rolling mill for 4 passes of rolling. The processing rate of each pass is 45±5% and the rolling speed is 500m / min; a battery aluminum foil coil with a thickness of 0.021mm is obtained.

[0131] (3) Finished product rolling: Pour foil rolling lubricating oil 2 into the aluminum foil finishing machine; roll the aluminum foil roll obtained in step (2) in the aluminum foil finishing machine for one pass, with a processing rate of 45% and a rolling speed of 500m / min; and obtain finished aluminum foil with a thickness of 0.013mm.

[0132] Performance testing

[0133] The tensile strength and elongation of the aluminum foils prepared in each embodiment and comparative example were tested using the method specified in "GB / T 22638.11-2023".

[0134] 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.

[0135] The surface cleanliness and uniformity of the finished aluminum foils prepared in each embodiment and comparative example were tested.

[0136] The performance test data of each embodiment and comparative example are shown in Table 1 below.

[0137] Table 1

[0138]

[0139] Note: The number of foil rolling passes in Table 1 includes the number of rough rolling passes of aluminum foil plus the number of finishing passes.

[0140] As can be seen from Table 1, when aluminum foil was prepared using the preparation method of this application in Examples 1 to 4, only 3 rolling passes were required, and the resulting aluminum foil had a tensile strength of over 220 MPa, an elongation of over 4.0%, and a thermal conductivity of over 152 W / (m·K).

[0141] Comparative Example 1 used a preparation method basically the same as that of Example 1, except that the annealing time for the first complete recrystallization annealing in Comparative Example 1 was 20 hours. The resulting aluminum foil had a tensile strength of 210 MPa, an elongation of 4.0%, and a thermal conductivity of 154 m·K. This may be because the first complete recrystallization annealing time in Comparative Example 1 was too long, resulting in abnormal microstructure growth, which significantly reduced the strength and elongation of the aluminum foil, but did not affect the thermal conductivity.

[0142] In Comparative Example 2, the elemental composition of the 3003 alloy aluminum cast-rolled billet was different from that in Example 1, and only one complete recrystallization annealing was performed; at least 5 rolling processes were required during the foil rolling process to obtain aluminum foil with a thickness that was basically the same as that in Example 1.

[0143] 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.

[0144] 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: The first annealed material was obtained by sequentially subjecting the 3003 alloy aluminum cast-rolled billet to a first cold rolling process and a first full recrystallization annealing process. The first annealed material is subjected to a second cold rolling process and a second full recrystallization annealing process in sequence to obtain a second annealed material. The second annealed material is then subjected to foil rolling; The temperature of the first complete recrystallization annealing treatment is 430℃~500℃, and the holding time is 5h~9h; The temperature for the second complete recrystallization annealing treatment is 410℃~485℃, and the holding time is 4h~8h; The cast-rolled billet, by mass percentage, comprises the following elemental components: 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 balance aluminum.

2. The preparation method according to claim 1, characterized in that, The temperature of the first complete recrystallization annealing treatment is 15°C to 20°C higher than the temperature of the second complete recrystallization annealing treatment.

3. The preparation method according to claim 1, characterized in that, The processing rate of the first cold rolling treatment is 30% to 55%; and / or, the processing rate of the second cold rolling treatment is 35% to 58%.

4. The preparation method according to claim 1, characterized in that, The second cold rolling process includes the following steps: The first annealed material is rolled in at least two passes; wherein the processing rate of the first pass is 50%~60% and the rolling speed is ≤350m / min.

5. The preparation method according to claim 1, characterized in that, The foil rolling process includes rolling the second annealed material once in each of the roughing mill, intermediate mill, and finishing mill.

6. The preparation method according to claim 5, characterized in that, When rolling is performed in the roughing mill, the processing rate is 50%~60%, and the rolling speed is ≤300m / min; and / or, When rolling is performed in the intermediate rolling mill, the processing rate is 45%~55%, and the rolling speed is ≤600m / min; and / or, When rolling is carried out in the finishing mill, the processing rate is 45%~50% and the rolling speed is ≤500m / min.

7. The preparation method according to any one of claims 1 to 6, characterized in that, The 3003 alloy aluminum cast-rolled billet is a plate, and the thickness of the 3003 alloy aluminum cast-rolled billet is 5mm~8mm.

8. A 3003 alloy aluminum foil, characterized in that, It is prepared by the method described in any one of claims 1 to 7.

9. The 3003 alloy aluminum foil as described in claim 8, characterized in that, The thickness of the 3003 alloy aluminum foil is 0.01mm~0.02mm.

10. The application of the 3003 alloy aluminum foil as described in any one of claims 8 to 9 in the preparation of batteries.

11. A battery, characterized in that, Includes the 3003 alloy aluminum foil as described in any one of claims 8 to 9.

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