阅读说明：本技术 一种1070高性能锂离子电池用铝箔及其制备方法 (1070 high-performance aluminum foil for lithium ion battery and preparation method thereof ) 是由 温倩 曹建峰 张深阳 高景忠 佟颖 夏卫华 刘建星 李晋 王进卫 杨翠琢 孟庆伟 于 2020-08-11 设计创作，主要内容包括：本发明公开了一种1070高性能锂离子电池用铝箔,属于锂离子电池用铝箔技术领域。铝箔包括以下质量百分比的成分：Si：0.01％-0.2％、Fe：0.01％-0.25％、Cu：0.02％-0.05％、Mn：0.01％-0.03％、Mg：0.001％-0.03％、Zn：0.001％-0.05％、V：0.001％-0.05％、Ti：0.01％-0.03％,其他单个杂质元素≤0.03％,余量的铝。1070高性能锂离子电池用铝箔的制备方法,包括：配料-熔炼-过滤-铸轧-冷轧-箔轧-分切-包装。采用上述方法制备的1070高性能锂离子电池用铝箔的抗拉强度≥210MPa,延伸率≥2.5％。因此,采用本发明所述的1070高性能锂离子电池用铝箔及其制备方法,能够解决现有的1070铝合金强度和延伸率低的问题。(The invention discloses a 1070 high-performance aluminum foil for a lithium ion battery, and belongs to the technical field of aluminum foils for lithium ion batteries. The aluminum foil comprises the following components in percentage by mass: si: 0.01% -0.2%, Fe: 0.01% -0.25%, Cu: 0.02% -0.05%, Mn: 0.01% -0.03%, Mg: 0.001% -0.03%, Zn: 0.001% -0.05%, V: 0.001% -0.05%, Ti: 0.01 to 0.03 percent of aluminum, less than or equal to 0.03 percent of other single impurity elements and the balance of aluminum. The preparation method of the 1070 high-performance aluminum foil for the lithium ion battery comprises the following steps: proportioning, smelting, filtering, casting and rolling, cold rolling, foil rolling, slitting and packaging. The tensile strength of the 1070 high-performance aluminum foil for the lithium ion battery prepared by the method is more than or equal to 210MPa, and the elongation is more than or equal to 2.5%. Therefore, the aluminum foil for 1070 high-performance lithium ion batteries and the preparation method thereof can solve the problem that the existing 1070 aluminum alloy is low in strength and elongation.)

1. An aluminum foil for 1070 high-performance lithium ion batteries, which is characterized in that: comprises the following components in percentage by mass: si: 0.01% -0.2%, Fe: 0.01% -0.25%, Cu: 0.02% -0.05%, Mn: 0.01% -0.03%, Mg: 0.001% -0.03%, Zn: 0.001% -0.05%, V: 0.001% -0.05%, Ti: 0.01 to 0.03 percent of aluminum, less than or equal to 0.03 percent of other single impurity elements and the balance of aluminum; and the mass percent of the aluminum is more than or equal to 99.7 percent.

2. The aluminum foil for 1070 high-performance lithium-ion batteries according to claim 1, wherein: the Ti and the B are Al-Ti intermediate alloy and Al-Ti-B wires, the mass percent of Ti in the Al-Ti-B wires is 4.5-5.5%, and the mass percent of B is 0.8-1.2%.

3. The method for preparing an aluminum foil for 1070 high-performance lithium-ion batteries according to any one of claims 1 to 2, comprising the steps of:

s1, blending, namely weighing corresponding raw materials according to component design;

s2, smelting, namely putting the prepared raw materials into a smelting furnace for smelting, and refining the aluminum alloy liquid after the raw materials are completely molten; adding Al-Ti intermediate alloy into a smelting furnace during smelting;

s3, filtering, namely performing double filtering by adopting a tubular filter box and ceramic filter plate mode, wherein the filtering temperature is 710-730 ℃;

s4, casting and rolling, wherein the filtered aluminum alloy liquid is injected into a casting and rolling machine through a runner for continuous casting and rolling to obtain a cast and rolled plate with the thickness of 7.0-8.0 mm;

s5, cold rolling, namely cold rolling the cast-rolled plate to obtain a cold-rolled plate with the thickness of 0.26-0.36 mm; carrying out homogenizing annealing when the thickness of the plate is 3.0-4.0mm, wherein the homogenizing annealing temperature is 500-580 ℃, and the heat preservation time is 20-25 h;

s6, foil rolling, namely obtaining a foil with the thickness of 0.01-0.015mm after rough rolling, medium rolling and finish rolling of the cold-rolled sheet;

s7, slitting, namely, putting the foil into a slitting machine for slitting, wherein the aluminum foil passes through a pinhole detector in the slitting process;

and S8, packaging and warehousing.

4. The method according to claim 3, wherein the aluminum foil for 1070 high-performance lithium ion batteries is prepared by the following steps: in the step S1, the raw material includes waste 1070 aluminum alloy with a mass percentage not higher than 15%, and the rest aluminum is pure aluminum ingot.

5. The method according to claim 3, wherein the aluminum foil for 1070 high-performance lithium ion batteries is prepared by the following steps: in the step S2, the hydrogen content is less than or equal to 0.12ml/100Al during smelting, the refining temperature is more than or equal to 730 ℃, the refining time is more than or equal to 30min, and the refining frequency is 3-4 h/time.

6. The method according to claim 3, wherein the aluminum foil for 1070 high-performance lithium ion batteries is prepared by the following steps: in step S3, Al-Ti-B wire is added to the launder before the caster before degassing and filtering.

7. The method according to claim 3, wherein the aluminum foil for 1070 high-performance lithium ion batteries is prepared by the following steps: in the step S4, the casting and rolling speed is 900-1100mm/min, the length of the casting and rolling area is 55-70mm, the same plate difference of the obtained cast and rolled plate is less than or equal to 0.03mm, the longitudinal plate difference is less than or equal to 0.12mm, and the convexity is 0-0.03 mm.

8. The method according to claim 3, wherein the aluminum foil for 1070 high-performance lithium ion batteries is prepared by the following steps: in the step S5, the cold rolling passes are respectively (7.0-8.0) mm- (3.0-4.0) mm- (2.0-2.5) mm- (1.0-1.3) mm- (0.5-0.8) mm- (0.26-0.36) mm; when the homogenization annealing is finished and the heat preservation is finished, a 1/2 furnace door is opened for cooling, the workpiece is discharged from the furnace for natural cooling when the temperature of furnace gas is reduced to 300 +/-20 ℃, and the workpiece is placed in the air in the annealing process and after the annealing.

9. The method according to claim 3, wherein the aluminum foil for 1070 high-performance lithium ion batteries is prepared by the following steps: in the step S6, the reduction passes of the foil rolling are respectively (0.26-0.36) mm- (0.12-0.18) mm- (0.07-0.09) mm- (0.035-0.045) mm- (0.016-0.025) mm- (0.01-0.015) mm.

10. The method according to claim 3, wherein the aluminum foil for 1070 high-performance lithium ion batteries is prepared by the following steps: in the step S7, the surface of the aluminum foil is subjected to corona treatment in the finish cutting process.

Technical Field

The invention belongs to the technical field of aluminum foils for lithium ion batteries, and particularly relates to a 1070 high-performance aluminum foil for lithium ion batteries and a preparation method thereof.

Background

The lithium ion battery has the advantages of high working voltage, light weight, large specific energy, long cycle life, safety, no memory effect, no environmental pollution and the like, and is rapidly developed in recent years, so that the lithium ion battery becomes an ideal power supply for mobile communication, notebook computers and digital products. With the continuous improvement of the call of people for energy conservation, environmental protection and green economy, especially the rapid promotion of new energy automobiles, lithium ion batteries also play an increasingly important role in the aspects of automobile power batteries and large energy storage batteries. Lithium ion batteries are being improved and developed in a direction of higher efficiency, lower cost, safety and environmental protection.

In a lithium ion battery, a current collector used for a positive electrode is generally an aluminum foil, that is, an aluminum foil for a lithium ion battery. The characteristics of the lithium ion battery determine that the aluminum foil product for the lithium ion battery needs to have the indexes of high conductivity, high strength, high elongation, good surface quality, good plate shape and the like, and the requirements are far higher than those of other aluminum foil products. The lithium ion battery is a daily-used consumer electronic product, has wide application range and large demand, and along with the rapid development of electronic industries at home and abroad and power battery foils mainly based on new energy automobiles, the using amount of the aluminum foil for the lithium ion battery is rapidly increased year by year, and is expected to increase by about 20 percent per year (the increase part is mainly based on the power battery) in the next several years. The demand of lithium ion batteries is continuously improved, the requirements on the comprehensive performance of the lithium ion batteries are higher and stricter, the quality and various performance indexes of the aluminum foils for the lithium ion batteries are gradually improved except for the aspects of positive/negative electrode materials, diaphragms, electrolyte, battery design and the like, and two trends of development in the future, namely thinning and high mechanical properties (high strength and high elongation), are the leading directions of research in the technical field of the aluminum foils for the lithium ion batteries.

The existing 1070 aluminum alloy has over-high purity, low content of alloy elements, coarse grains, and the strength of the aluminum alloy of 150-180MPa, and cannot meet the requirement of high strength of the aluminum foil.

Disclosure of Invention

The invention aims to provide an aluminum foil for a 1070 high-performance lithium ion battery, which solves the problem that the existing 1070 aluminum alloy is low in strength and elongation. The invention also aims to provide a preparation method of the aluminum foil for the 1070 high-performance lithium ion battery.

In order to achieve the purpose, the invention provides an aluminum foil for a 1070 high-performance lithium ion battery, which comprises the following components in percentage by mass: si: 0.01% -0.2%, Fe: 0.01% -0.25%, Cu: 0.02% -0.05%, Mn: 0.01% -0.03%, Mg: 0.001% -0.03%, Zn: 0.001% -0.05%, V: 0.001% -0.05%, Ti: 0.01 to 0.03 percent of aluminum, less than or equal to 0.03 percent of other single impurity elements and the balance of aluminum; and the mass percent of the aluminum is more than or equal to 99.7 percent.

Preferably, the Ti and the B are Al-Ti intermediate alloy and Al-Ti-B wires, the mass percent of Ti in the Al-Ti-B wires is 4.5-5.5%, and the mass percent of B in the Al-Ti-B wires is 0.8-1.2%.

The preparation method of the aluminum foil for the 1070 high-performance lithium ion battery is characterized by comprising the following steps of:

s1, blending, namely weighing corresponding raw materials according to component design;

s2, smelting, namely putting the prepared raw materials into a smelting furnace for smelting, and refining the aluminum alloy liquid after the raw materials are completely molten; adding Al-Ti intermediate alloy into a smelting furnace during smelting;

s3, filtering, namely performing double filtering by adopting a tubular filter box and ceramic filter plate mode, wherein the filtering temperature is 710-730 ℃;

s4, casting and rolling, wherein the filtered aluminum alloy liquid is injected into a casting and rolling machine through a runner for continuous casting and rolling to obtain a cast and rolled plate with the thickness of 7.0-8.0 mm;

s5, cold rolling, namely cold rolling the cast-rolled plate to obtain a cold-rolled plate with the thickness of 0.26-0.36 mm; carrying out homogenizing annealing when the thickness of the plate is 3.0-4.0mm, wherein the homogenizing annealing temperature is 500-580 ℃, and the heat preservation time is 20-25 h;

s6, foil rolling, namely obtaining a foil with the thickness of 0.01-0.015mm after rough rolling, medium rolling and finish rolling of the cold-rolled sheet;

s7, slitting, namely, putting the foil into a slitting machine for slitting, wherein the aluminum foil passes through a pinhole detector in the slitting process;

and S8, packaging and warehousing.

Preferably, in step S1, the raw material includes waste 1070 aluminum alloy with a mass percentage of not higher than 15%, and the rest aluminum is pure aluminum ingot.

Preferably, in the step S2, the hydrogen content is less than or equal to 0.12ml/100Al during smelting, the refining temperature is more than or equal to 730 ℃, the refining time is more than or equal to 30min, and the refining frequency is 3-4 h/time.

Preferably, in the step S3, the Al-Ti-B wire is added to the launder before the caster before degassing and filtering.

Preferably, in the step S4, the casting and rolling speed is 900-.

Preferably, in the step S5, the cold rolling passes are (7.0-8.0) mm- (3.0-4.0) mm- (2.0-2.5) mm- (1.0-1.3) mm- (0.5-0.8) mm- (0.26-0.36) mm respectively; when the homogenization annealing is finished and the heat preservation is finished, a 1/2 furnace door is opened for cooling, the workpiece is discharged from the furnace for natural cooling when the temperature of furnace gas is reduced to 300 +/-20 ℃, and the workpiece is placed in the air in the annealing process and after the annealing.

Preferably, in the step S6, the reduction passes of the foil rolling are (0.26-0.36) mm- (0.12-0.18) mm- (0.07-0.09) mm- (0.035-0.045) mm- (0.016-0.025) mm- (0.01-0.015) mm respectively.

Preferably, in step S7, the surface of the aluminum foil is subjected to corona treatment during the fine cutting process.

The aluminum foil for 1070 high-performance lithium ion batteries and the preparation method thereof have the beneficial effects that:

1. the Cu element and the Mn element are added into the aluminum alloy, and the Cu element mainly exists in a solid solution state, contributes to improving the strength of the aluminum alloy and also has influence on grain recrystallization. The existence of Mn element can form a chemical combination phase with Fe, thereby reducing the harmful effect of Fe element, simultaneously increasing the recrystallization temperature of the aluminum alloy and playing an effective role in improving the strength and the plasticity of the aluminum alloy.

2. During casting and rolling, the mode of the tubular filter box and the ceramic filter plate is adopted for double filtration, the purity of the molten aluminum can be improved by adopting double filtration, and the defect rates of pinholes, air passages, slag inclusion and the like in the cast-rolled plate are reduced.

3. In the cold rolling process, the homogenization annealing is carried out when the thickness of the plate is 3.0-4.0mm, the homogenization annealing is carried out on the aluminum alloy plate, the uneven structure and components formed by the cast-rolled blank due to the high cooling speed can be eliminated, the form of a compound is improved, the structure and the components of the aluminum alloy are more uniform, and the quality of the final product aluminum foil product is effectively improved.

4. During smelting, adding Al-Ti intermediate alloy into the aluminum alloy; before casting and rolling, Al-Ti-B wires are added into a flow tank, and the aluminum alloy is subjected to modification treatment through Ti and B, so that the grain size of the aluminum alloy can be effectively reduced, and a cast-rolled plate with fine and uniform grains is obtained.

The technical solution of the present invention is further described in detail by the following examples.

Detailed Description

1070 aluminum alloy: the aluminum alloy is an aluminum alloy variety with the corresponding alloy brand 1070 according to the requirements of the national standard GB/T3190-2008, wherein the aluminum content is not less than 99.70%.

Aluminum foil for lithium ion battery: the aluminum foil is suitable for aluminum foil products for lithium ion battery collectors, and is mainly applied to the fields of batteries for digital electronic products such as mobile phones, flat plates and notebook computers, power batteries for new energy automobile storage batteries, large energy storage batteries and the like.

An aluminum foil for a 1070 high-performance lithium ion battery comprises the following components in percentage by mass: si: 0.01% -0.2%, Fe: 0.01% -0.25%, Cu: 0.02% -0.05%, Mn: 0.01% -0.03%, Mg: 0.001% -0.03%, Zn: 0.001% -0.05%, V: 0.001% -0.05%, Ti: 0.01 to 0.03 percent of aluminum, less than or equal to 0.03 percent of other single impurity elements and the balance of aluminum; and the mass percent of the aluminum is more than or equal to 99.7 percent.

The Ti and the B are Al-Ti intermediate alloy and Al-Ti-B wires, the mass percent of Ti in the Al-Ti-B wires is 4.5-5.5%, and the mass percent of B is 0.8-1.2%.

A small amount of Cu element and Mn element are added into 1070 aluminum alloy, and the Cu element can form solid solution phase Al₂Cu is dispersedly distributed at the crystal boundary, so that the Cu has a pinning effect on dislocation movement in subsequent processing, and the strength and the recrystallization temperature of the alloy are effectively improved; meanwhile, the existence of Cu element can form a second phase to prevent the growth of crystal grains. In conclusion, the existence of the Cu element can effectively improve the performance index of the final aluminum foil. The existence of Mn element can form a combined phase (Fe, Mn) Al with Fe₆Thereby reducing the harmful effect of Fe element, and simultaneously, Mn can also improve the recrystallization temperature of the aluminum alloy, and has effective effect on improving the strength and plasticity of the aluminum alloy.

The preparation method of the aluminum foil for the 1070 high-performance lithium ion battery comprises the following steps:

s1, mixing, and weighing corresponding raw materials according to the component design. The raw materials comprise waste materials of 1070 percent of aluminum alloy with the mass percent not higher than 15 percent, and the rest aluminum is pure aluminum ingots. The waste material of the aluminum alloy can be reused, and the material cost is reduced.

S2, smelting, namely putting the prepared raw materials into a smelting furnace for smelting, and refining the aluminum alloy liquid after the raw materials are completely molten; during smelting, Al-Ti intermediate alloy is added into a smelting furnace. The furnace burden is kept clean during smelting, the melt quality is good, and the production requirement of aluminum foil is met. The hydrogen content is less than or equal to 0.12ml/100Al, the refining temperature is more than or equal to 730 ℃, the refining time is more than or equal to 30min, and the refining frequency is 3-4 h/time.

S3, filtering, and performing double filtration by adopting a tubular filter box and ceramic filter plate mode, wherein the filtering temperature is 710-730 ℃. The double filtration can improve the purity of the aluminum liquid and reduce the defect rate of pinholes, air passages, slag inclusion and the like in the cast-rolling plate. Before degassing and filtering, Al-Ti-B wires are added into a launder in front of a casting and rolling machine.

S4, casting and rolling, and injecting the filtered aluminum alloy liquid into a casting and rolling machine through a runner for continuous casting and rolling to obtain a casting and rolling plate with the thickness of 7.0-8.0 mm. The casting and rolling speed is 900-1100mm/min, the length of the casting and rolling area is 55-70mm, the same plate difference of the obtained cast and rolled plate is less than or equal to 0.03mm, the longitudinal plate difference is less than or equal to 0.12mm, and the convexity is 0-0.03 mm.

Al-Ti intermediate alloy and Al-Ti-B wires are respectively added into the aluminum liquid before smelting and cast rolling, and double refinement modification treatment is carried out on the aluminum alloy, so that the crystal grains of the aluminum alloy can be effectively refined, and the crystal grain structure of the cast-rolled plate is finer and more uniform. The final content of the B element in the aluminum alloy cannot be detected because the content of the B element is less.

And S5, cold rolling, namely cold rolling the cast-rolled plate to obtain a cold-rolled plate with the thickness of 0.26-0.36 mm. The cold rolling passes are respectively (7.0-8.0) mm- (3.0-4.0) mm- (2.0-2.5) mm- (1.0-1.3) mm- (0.5-0.8) mm- (0.26-0.36) mm. The process parameters in the cold rolling are shown in table 1.

TABLE 11070 Cold-Rolling Process parameters of aluminum foil for high-Performance lithium-ion Battery

And carrying out homogenizing annealing when the thickness of the plate is 3.0-4.0mm, wherein the homogenizing annealing temperature is 500-580 ℃, and the heat preservation time is 20-25 h. The aluminum alloy plate is subjected to homogenizing annealing, so that the structural component unevenness formed by the cast-rolling blank due to high cooling speed can be eliminated, the form of a compound is improved, the aluminum alloy structure and the component are more uniform, and the quality of the final product aluminum foil product is effectively improved.

When the homogenization annealing is finished and the heat preservation is finished, a 1/2 furnace door is opened for cooling, the workpiece is discharged from the furnace for natural cooling when the temperature of furnace gas is reduced to 300 +/-20 ℃, and the workpiece is placed in the air in the annealing process and after the annealing.

Controlling the quality of the plate shape during cold rolling:

firstly, after the working roll is replaced each time, the preheating of the roll is maintained for more than 10 minutes, 2-3 rolls of thick materials are produced before the finished product pass so as to improve the thermal convexity of the roll and stabilize the roll shape, and the on-line plate shape is not more than 15I in the finished product pass;

secondly, selecting a proper plate shape control curve according to the width of the product to ensure the plate shape quality;

and thirdly, ensuring that the plate shape control system is normal when the roller is replaced and maintained regularly.

Surface quality control during cold rolling:

cleaning a material roll before feeding, cleaning a roller during roller changing, and cleaning a guide roller and a plate type roller before production;

secondly, replacing a new roller before a finished product is produced, detecting that the surface of the working roller has no serious knife mark, vibration line and the like, and determining whether the roller state meets the surface requirement of the product;

checking whether the surface has defects such as roller mark, scratch, aluminum adhesion, surface stripe and the like to avoid batch surface defects;

and fourthly, ensuring the rolling oil filtering system to be normal so as to ensure the quality of the rolling surface.

S6, foil rolling, namely obtaining the foil with the thickness of 0.01-0.015mm after rough rolling, medium rolling and finish rolling of the cold-rolled sheet. The reduction passes of the foil rolling are respectively (0.26-0.36) mm- (0.12-0.18) mm- (0.07-0.09) mm- (0.035-0.045) mm- (0.016-0.025) mm- (0.01-0.015) mm.

The conditions of the finished pass rolling of the 1070 high-performance aluminum foil for the lithium ion battery are shown in table 2.

TABLE 21070 roller condition of finished aluminum foil pass for high performance lithium ion battery

Thickness of finished product mm	Roller convexity thousandths	Roughness (Ra) of roller
			0.012/0.015	65	0.10-0.15
0.010	65	0.07-0.12

The requirements of the rolling oil in the production of the aluminum foil for 1070 high-performance lithium ion batteries are shown in table 3.

TABLE 31070 Rolling oil requirements in the production of aluminum foil for high-performance lithium ion batteries

And S7, slitting, namely, putting the foil into a slitting machine for slitting, wherein the aluminum foil passes through a pinhole detector in the slitting process, so that the quality of product pinholes is ensured to be good. And secondary cutting is carried out on the fine cutting equipment to obtain the width specification required by the customer. And in the fine cutting process, the surface of the aluminum foil is subjected to corona treatment so as to improve the surface dyne value of the aluminum foil, improve the wettability of the surface of the aluminum foil and facilitate subsequent spraying treatment.

And S8, packaging and warehousing.

The present invention will be further described with reference to the following examples, which are provided for the purpose of illustrating the present invention, and the scope of the present invention is not limited by the following examples. The cost ratios of the aluminum alloys in examples 1 to 4 are shown in Table 4.

TABLE 41070 composition Table of examples of aluminum foils for high-performance lithium ion batteries

Alloy element	Si	Fe	Cu	Mn	Mg	Zn	V	Ti	Al
										Example one	0.04	0.17	0.02	0.01	0.001	0.001	0.001	0.020	Balance of
Example two	0.05	0.15	0.02	0.01	0.001	0.001	0.001	0.022	Balance of
										EXAMPLE III	0.04	0.14	0.02	0.03	0.001	0.001	0.001	0.020	Balance of
Example four	0.05	0.14	0.04	0.015	0.001	0.001	0.001	0.026	Balance of
										EXAMPLE five	0.05	0.15	0.03	0.02	0.001	0.001	0.001	0.029	Balance of
EXAMPLE six	0.04	0.13	0.04	0.03	0.001	0.001	0.001	0.025	Balance of
										EXAMPLE seven	0.05	0.10	0.05	0.03	0.001	0.001	0.001	0.023	Balance of

The aluminum alloys of the above examples were made into aluminum foils of 0.01 to 0.13mm and 0.015mm, respectively, and mechanical property measurements were made, and the results are shown in Table 5.

TABLE 51070 mechanical properties of aluminum foil examples for high performance lithium ion batteries

The aluminum foil with the thickness of 0.01-0.13mm, which is prepared by adopting the 1070 high-performance lithium ion battery aluminum foil and the preparation method thereof, has the tensile strength of more than or equal to 210MPa and the elongation of more than or equal to 2.5 percent; the tensile strength of the aluminum foil with the thickness of 0.015mm is more than or equal to 210MPa, and the elongation is more than or equal to 2.5 percent.

Therefore, the aluminum foil for 1070 high-performance lithium ion batteries and the preparation method thereof can solve the problem that the existing 1070 aluminum alloy is low in strength and elongation.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the invention without departing from the spirit and scope of the invention.