An ultrahigh strength 13-μm battery aluminum foil and a method for preparing the same

Abstract

The application discloses a kind of ultrahigh-strength 13 μm battery aluminum foil and preparation method thereof, belong to battery aluminum foil technical field.The battery aluminum foil includes the following mass percentage of alloy elements:Si 0.23~0.27%, Fe 0.44~0.50%, Cu 0.185~0.205%, Mn 0.86~0.90%, Mg 1.19~1.24%, Cr≤0.04%, Zn≤0.06%, Ti 0.01~0.025%;Its preparation method includes steps: (1) smelting and casting; (2) homogenization; (3) hot rolling, after homogenization the aluminum alloy ingot is carried out multiple pass hot rolling to obtain hot-rolled coil, and control final rolling temperature≥330 DEG C; (4) cold rolling, after hot-rolled coil cooling, multiple pass cold rolling is carried out to obtain cold-rolled product, and cold-rolled product annealing is carried out after cold rolling; (5) foil rolling, after annealing after cold-rolled product cooling, multiple pass foil rolling is carried out, and foil rolling pass is carried out once foil rolling intermediate annealing; (6) slitting, after slitting, battery aluminum foil is obtained.The application is combined by alloy composition regulation and preparation process, and ultrahigh-strength tensile battery aluminum foil is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery aluminum foil, in particular to a kind of ultra-high strength 13 μm battery aluminum foil and preparation method thereof. BACKGROUND

[0002] Lithium ion battery industry usually uses rolled aluminum foil as positive current collector, with the development of lithium ion battery, higher requirements are put forward to the quality and performance of its positive current collector battery foil, in addition to the increasing requirements of plate shape quality, surface quality, surface cleanliness, it also requires it to have high mechanical properties. At present, 13 μm battery foil product of 1060, 1100 alloy is prepared by conventional process, its tensile strength is usually 190~240 MPa, the tensile strength of 1100 alloy can reach 280 MPa under special production process, although it has relatively high strength, but still can not meet the demand of high-end lithium ion battery for ultra-high strength tensile battery foil. SUMMARY

[0003] In order to solve the above technical problems, the present application provides a kind of ultra-high strength 13 μm battery aluminum foil and preparation method thereof, by combining alloy composition control and preparation process, ultra-high strength tensile battery aluminum foil is obtained.

[0004] The technical scheme adopted by the present application is:

[0005] On the one hand, the present application provides a kind of ultra-high strength 13 μm battery aluminum foil, which comprises the following mass percentage of alloy elements: Si 0.23~0.27%, Fe 0.44~0.50%, Cu 0.185~0.205%, Mn 0.86~0.90%, Mg 1.19~1.24%, Cr≤0.04%, Zn≤0.06%, Ti 0.01~0.025%, the balance is Al and inevitable impurity elements, and the total content of impurity elements is≤0.15%.

[0006] On the other hand, the present application provides a kind of preparation method of ultra-high strength 13 μm battery aluminum foil, comprising the following steps:

[0007] (1) melting and casting, according to alloy composition and proportion, the corresponding raw materials are weighed and put into the melting furnace for melting, after complete melting, the aluminum alloy liquid is refined, the pure aluminum melt is obtained by online SNIF degassing and online filtering, and the aluminum alloy ingot is obtained by casting;

[0008] (2) homogenization, the aluminum alloy ingot is put into the heating furnace for homogenization treatment;

[0009] (3) hot rolling, the aluminum alloy ingot after homogenization is subjected to multi-pass hot rolling to obtain hot rolled coil, and the final rolling temperature is controlled to be≥330℃;

[0010] (4) cold rolling, after the hot-rolled coil is cooled, multi-pass cold rolling is performed to obtain a cold-rolled product, and cold-rolled product annealing is performed after cold rolling;

[0011] (5) foil rolling, after the cold-rolled product after annealing is cooled, multi-pass foil rolling is performed, and one foil rolling intermediate annealing is performed between foil rolling passes;

[0012] (6) slitting, after slitting, the battery aluminum foil is obtained.

[0013] Further, the homogenization treatment process in the step (2) is 605±10℃*5-10h+550±10℃*0-4h.

[0014] Further, the hot-rolled coil thickness in the step (3) is 2.0-2.1mm.

[0015] Further, the cold rolling passes in the step (4) are three passes in total, and the cold-rolled product thickness is 0.21-0.25mm.

[0016] Further, the cold-rolled product annealing process in the step (4) is 360±10℃*6-8h.

[0017] Further, the foil rolling in the step (5) includes: a first pass, from 0.21-0.25mm to 0.12mm; a second pass, to 65μm; a third pass, to 32μm; a fourth pass, to 19μm; and a fifth pass, to 13μm.

[0018] Further, the foil rolling intermediate annealing is performed after the third pass in the step (5), and the foil rolling intermediate annealing process is 300±10℃*6-8h.

[0019] The present application has the following beneficial effects:

[0020] The present application provides a kind of ultra-high strength 13 μm battery aluminum foil and preparation method thereof, by optimizing alloy composition, mainly increase the content of Si, Cu, Mn, Mg alloy element, improve the degree of alloying of aluminum alloy, its main strengthening phase is MnAl6 And (FeMn) Al6, can effectively hinder dislocation movement, thereby improving the strength and hardness of alloy, while maintaining good corrosion resistance and machinability;In addition, after optimizing and adjusting alloy composition, the degree of alloying is improved, the strength and hardness of battery foil are high, at the same time, it also brings difficulties to rolling process, therefore, the present application also optimizes preparation process, mainly after cold rolling, the cold-rolled product is annealed, and one intermediate annealing is added in foil rolling intermediate pass, to ensure that rolling process proceeds smoothly.The battery aluminum foil prepared by the present application can reach 320MPa in tensile strength, with ultra-high strength tensile strength. DETAILED DESCRIPTION

[0021] The present application provides a kind of ultra-high strength 13 μm battery aluminum foil and its preparation method, to make the purpose, technical scheme and effect of the present application more clear, explicit, the following is further detailed to the present application.It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0022] The present application provides a kind of ultra-high strength 13 μm battery aluminum foil, including the following mass percentage of alloy elements: Si 0.23~0.27%, Fe 0.44~0.50%, Cu 0.185~0.205%, Mn 0.86~0.90%, Mg 1.19~1.24%, Cr≤0.04%, Zn≤0.06%, Ti 0.01~0.025%, the balance is Al and unavoidable impurity elements, and the total content of impurity elements≤0.15%.

[0023] The present application mainly increases the content of Si, Cu, Mn, Mg alloy elements, improves the alloying degree of aluminum alloy, can form MnAl6, (FeMn)Al6, (Al, Fe, Mn, Si) four-phase, (Al, Mn, Si) three-phase, (Al, Mn, Mg, Fe) four-phase, etc. in battery aluminum foil finished product, and solid solution has Mg2Si phase, wherein the main strengthening phase is MnAl6 and (FeMn)Al6, can effectively hinder dislocation movement, thereby improving the strength and hardness of alloy, while maintaining good corrosion resistance and machinability.

[0024] After adjusting alloy composition, the alloying degree is improved, the strength and hardness of battery foil are improved, but at the same time, it also brings difficulties to the rolling process, therefore, the preparation process must also be improved, especially the rolling process.

[0025] On the basis of adjusting alloy composition, the present application also provides a kind of preparation method of ultra-high strength 13 μm battery aluminum foil for the alloy composition aluminum alloy, comprising the following steps:

[0026] (1) melting and casting, according to alloy component and proportion, the corresponding raw material is weighed and put into melting furnace for melting, after complete melting, the aluminum alloy liquid is refined, and pure aluminum melt is obtained by on-line SNIF degassing and plate filter, pipe filter, and aluminum alloy ingot is obtained by casting the aluminum melt;

[0027] (2) homogenization, the aluminum alloy ingot is placed in heating furnace for homogenization treatment, specifically, the homogenization treatment process is 605±10 ℃*5~10 h+550±10 ℃*0~4 h;

[0028] (3) hot rolling, after the homogenized aluminum alloy ingot is discharged, multi-pass hot rolling is directly performed to obtain a hot-rolled coil, and the finish rolling temperature is controlled to be greater than or equal to 330 DEG C; the initial thickness of the hot rolling is 596 mm, and after 15-19 pass hot rough rolling and 4 pass hot finish rolling, the finished hot-rolled coil has a thickness of 2.0-2.1 mm and is in an F state;

[0029] (4) cold rolling, after the hot-rolled plate is cooled, multi-pass cold rolling is performed to obtain a cold-rolled finished product, and the cold-rolled finished product is annealed after the cold rolling; the cold rolling is performed in three passes to obtain a cold-rolled finished product with a thickness of 0.21-0.25 mm, and the cold-rolled finished product is annealed at 360±10 DEG C for 6-8 h, preferably at 360 DEG C for 7 h; that is, the cold rolling process is as follows: 2.0-2.1 mm / F→three passes to 0.21-0.25 mm / H19→0.21-0.25 mm / O state;

[0030] (5) foil rolling, after the annealed cold-rolled finished product is cooled, multi-pass foil rolling is performed, and intermediate annealing is performed between the foil rolling passes; the foil rolling specifically includes five passes: the first pass is to press from 0.21-0.25 mm to 0.12 mm; the second pass is to press to 65 μm; the third pass is to press to 32 μm; the fourth pass is to press to 19 μm; and the fifth pass is to press to 13 μm, and intermediate annealing is performed after the third pass, and the intermediate annealing process is 300±10 DEG C for 6-8 h, preferably 300 DEG C for 7 h; that is, the foil rolling process is as follows: 0.21-0.25 mm / O state→0.12 mm / H14→0.065 mm / H18→0.032 mm / H19→0.032 mm / O state→0.019 mm / H14→0.013 mm / H14;

[0031] (6) slitting, and a battery aluminum foil is obtained after slitting.

[0032] In the present application, the cold-rolled finished product needs to be annealed in step (4) to eliminate work hardening, restore the plasticity and cold deformation capacity of the material, refine the grains, adjust the structure, eliminate internal structural defects, and prepare for subsequent foil rolling passes. In addition, due to the high degree of alloying of the aluminum alloy in the present application, the tensile strength increases rapidly under the same processing rate during rolling, therefore, an intermediate annealing pass is added during aluminum foil rolling to prevent the degree of work hardening from being too high, which leads to excessive rolling force and difficulty in thinning during foil rolling.

[0033] Example 1

[0034] The present embodiment provides a preparation method of an ultrahigh-strength 13 μm battery aluminum foil, which comprises the following steps:

[0035] (1) smelting and casting, the alloy elements are compounded according to the following mass percentage: Si 0.27%, Fe 0.50%, Cu 0.20%, Mn 0.90%, Mg 1.24%, Cr 0.03%, Zn 0.05%, Ti 0.020%, and the balance is Al, the raw materials are put into a smelting furnace for smelting, after complete melting, the aluminum alloy liquid is refined, and the pure aluminum melt is obtained through online SNIF degassing and plate filtration and tube filtration, and the aluminum melt is cast to obtain an aluminum alloy ingot;

[0036] (2) homogenization, the aluminum alloy ingot is placed in a heating furnace for homogenization treatment, specifically, the homogenization treatment process is 605℃*10h+550℃*2h;

[0037] (3) hot rolling, the aluminum alloy ingot after homogenization is directly subjected to multi-pass hot rolling to obtain a hot-rolled plate, and the final rolling temperature is controlled to be greater than or equal to 330℃; the initial thickness of the hot-rolled plate is 596mm, and after 15-19 passes of hot rough rolling and 4 passes of hot finish rolling, the thickness of the hot-rolled product is 2.1mm, and the state is F;

[0038] (4) cold rolling, after the hot-rolled plate is cooled, multi-pass cold rolling is performed to obtain a cold-rolled product, and the cold-rolled product is annealed after cold rolling; the cold rolling passes a total of three times to obtain a cold-rolled product with a thickness of 0.25mm, and the cold-rolled product is annealed, and the cold-rolled product annealing process is 360℃*7h; that is, the cold rolling process is: 2.1mm / F→three passes to 0.25mm / H19→0.25mm / O state;

[0039] (5) foil rolling, after the annealed cold-rolled product is cooled, multi-pass foil rolling is performed, and intermediate annealing is performed once between foil rolling passes; the foil rolling specifically includes five passes: the first pass, from 0.25mm to 0.12mm; the second pass, to 65μm; the third pass, to 32μm; the fourth pass, to 19μm; the fifth pass, to 13μm, and intermediate annealing is performed after the third pass, and the foil rolling intermediate annealing process is 300℃*7h; that is, the foil rolling process is: 0.25mm / O state→0.12mm / H14→0.065mm / H18→0.032mm / H19→0.032mm / O state→0.019mm / H14→0.013mm / H14;

[0040] (6) slitting, and the battery aluminum foil is obtained after slitting.

[0041] The battery aluminum foil prepared in the above embodiment 1 is subjected to mechanical property detection, and the tensile strength is 325MPa.

[0042] Embodiment 2

[0043] The embodiment provides a preparation method of ultrahigh-strength 13-micron battery aluminum foil, comprising the following steps:

[0044] (1) smelting and casting, alloy element ingredients are as follows in percentage by mass: Si 0.24%, Fe 0.44%, Cu 0.19%, Mn 0.86%, Mg 1.19%, Cr 0.02%, Zn 0.04%, Ti 0.015%, and the balance is Al, raw materials are put into a smelting furnace for smelting, after complete melting, the aluminum alloy liquid is refined, and the pure aluminum melt is obtained through online SNIF degassing and plate filtration and tube filtration, and the aluminum melt is cast to obtain an aluminum alloy ingot;

[0045] (2) homogenization, the aluminum alloy ingot is placed into a heating furnace for homogenization treatment, specifically, the homogenization treatment process is 615 DEG C * 8h, and the temperature is reduced to 560 DEG C and directly discharged from the furnace;

[0046] (3) hot rolling, the aluminum alloy ingot after homogenization is directly subjected to multi-pass hot rolling to obtain a hot-rolled plate, and the final rolling temperature is greater than or equal to 330 DEG C; the initial thickness of the hot-rolled plate is 596 mm, and after 17-pass hot rough rolling and 4-pass hot finish rolling, the thickness of the hot-rolled product is 2.0 mm, and the state is F;

[0047] (4) cold rolling, after the hot-rolled plate is cooled, multi-pass cold rolling is carried out to obtain a cold-rolled product, and the cold-rolled product is annealed after cold rolling; the cold rolling is three passes, the thickness of the cold-rolled product is 0.22 mm, and the cold-rolled product is annealed, and the cold-rolled product annealing process is 360 DEG C * 7h; that is, the cold rolling process is: 2.0 mm / F→three passes to 0.22 mm / H19→0.22 mm / O state;

[0048] (5) foil rolling, after the cold-rolled product after annealing is cooled, multi-pass foil rolling is carried out, and intermediate annealing is carried out once between foil rolling passes; the foil rolling specifically includes five passes: the first pass is from 0.22 mm to 0.12 mm; the second pass is to 65 microns; the third pass is to 32 microns; the fourth pass is to 19 microns; and the fifth pass is to 13 microns, and intermediate annealing is carried out after the third pass, and the foil rolling intermediate annealing process is 300 DEG C * 7h; that is, the foil rolling process is: 0.22 mm / O state→0.12 mm / H14→0.065 mm / H18→0.032 mm / H19→0.032 mm / O state→0.019 mm / H14→0.013 mm / H14;

[0049] (6) slitting, and the battery aluminum foil is obtained after slitting.

[0050] The battery aluminum foil prepared in the above embodiment 2 is subjected to mechanical property detection, and the tensile strength is 322 MPa.

[0051] Example 3

[0052] The difference between this example 3 and example 2 is that different annealing processes are used to anneal the 13 μm foil finished product prepared in example 2 to obtain battery aluminum foils with different mechanical properties to meet the needs of different customers.

[0053] This example is annealed by using the following annealing process, and the corresponding tensile strength is detected, which is as follows:

[0054] When the annealing process is 150℃*1h, the tensile strength is 302MPa;

[0055] When the annealing process is 180℃*1h, the tensile strength is 297MPa;

[0056] When the annealing process is 210℃*1h, the tensile strength is 258MPa;

[0057] When the annealing process is 240℃*1h, the tensile strength is 242MPa;

[0058] When the annealing process is 270℃*1h, the tensile strength is 225MPa;

[0059] When the annealing process is 300℃*1h, the tensile strength is 132MPa;

[0060] When the annealing process is 330℃*1h, the tensile strength is 118MPa.

[0061] It can be seen that by using different annealing processes to anneal the 13 μm foil finished product, the mechanical properties can be obviously changed to meet the diversified needs of the market.

[0062] Comparative Example 1

[0063] This comparative example uses 1100 aluminum alloy to prepare 13 μm battery aluminum foil, and the 1100 aluminum alloy includes the following alloying elements in mass percentage: Si 0.05-0.08%, Fe 0.42-0.48%, Cu 0.07-0.10%, Mn 0.025-0.035%, Mg≤0.01%, Cr≤0.01%, Zn≤0.01%, Ti≤0.015%, the balance being Al and unavoidable impurity elements, and the total content of impurity elements is ≤0.15%. In this example, the composition of the 1100 aluminum alloy is as follows: Si 0.06%, Fe 0.45%, Cu 0.10%, Mn 0.03%, Mg≤0.01%, Cr≤0.01%, Zn≤0.01%, Ti≤0.015%, the balance being Al and unavoidable impurity elements.

[0064] The homogenization process of the 1100 aluminum alloy is the same as that of Example 1, and the hot rolling, cold rolling and foil rolling processes are as follows:

[0065] Hot rolling: the thickness of the hot rolling product is 3.2 mm, and the state is F;

[0066] Cold rolling: the cold rolling starting thickness is 3.2 mm, and the cold rolling is annealed after one pass, and the thickness is 1.5 mm after one pass. The annealing process is 360℃*7h. The cold rolling product is obtained after three passes of rolling. The thickness of the cold rolling product is 0.22 mm, and the state is H18;

[0067] Foil rolling: the foil rolling is 5 passes, i.e. 0.22-0.1 mm→40 μm→20 μm→13 μm.

[0068] The mechanical properties of the battery aluminum foil prepared in the above Comparative Example 1 are detected, and the tensile strength is 218 MPa.

[0069] The mechanical properties of the battery aluminum foils of Example 1 and Comparative Example 1 are compared. The tensile strength of the battery aluminum foil of Example 1 can reach more than 320 MPa, while that of Comparative Example 1 is only 218 MPa. The battery aluminum foil of Example 1 has super high strength and is suitable for batteries with high strength requirements.

[0070] It should be noted that the parts not mentioned in the present application can be realized by using or referring to existing technology, such as smelting process, casting process, etc. using existing technology.

[0071] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present application should also be within the scope of the present application.

Claims

1. A method for preparing ultra-high strength 13μm battery aluminum foil, characterized in that, Including the following steps: (1) Smelting and casting: Weigh the corresponding raw materials according to the alloy composition and proportion, and put them into the smelting furnace for smelting. After complete melting, refine the aluminum alloy liquid, and obtain pure aluminum melt through online SNIF degassing and online filtration. The aluminum melt is then cast to obtain aluminum alloy ingots. (2) Homogenization: The aluminum alloy ingot is placed in a heating furnace for homogenization treatment; (3) Hot rolling: The homogenized aluminum alloy ingot is hot rolled in multiple passes to obtain hot rolled coils, and the final rolling temperature is controlled to be ≥330℃. (4) Cold rolling: After the hot-rolled coil is cooled, it is cold rolled in multiple passes to obtain the cold-rolled finished product, and the cold-rolled finished product is annealed after cold rolling; (5) Foil rolling: After the cold-rolled finished product is cooled after annealing, multiple foil rolling passes are performed, and an intermediate foil rolling annealing is performed between foil rolling passes. (6) Cutting, the cut results in battery aluminum foil; The ultra-high strength 13μm battery aluminum foil comprises the following alloying elements by mass percentage: Si 0.23~0.27%, Fe 0.44~0.50%, Cu 0.185~0.205%, Mn 0.86~0.90%, Mg 1.19~1.24%, Cr≤0.04%, Zn≤0.06%, Ti 0.01~0.025%, with the balance being Al and unavoidable impurity elements, and the total impurity element content ≤0.15%. The homogenization process in step (2) is 605±10℃*5~10h+550±10℃*0~4h; In step (4), the annealing process for the cold-rolled finished product is 360±10℃*6~8h; The foil rolling in step (5) includes: a first pass, rolling from 0.21~0.25mm to 0.12mm; a second pass, rolling to 65μm; a third pass, rolling to 32μm; a fourth pass, rolling to 19μm; and a fifth pass, rolling to 13μm. In step (5), intermediate foil annealing is performed after the third pass, and the intermediate foil annealing process is 300±10℃*6~8h.

2. The method for preparing an ultra-high strength 13μm battery aluminum foil according to claim 1, characterized in that, In step (3), the thickness of the hot-rolled coil is 2.0~2.1mm.

3. The method for preparing an ultra-high strength 13μm battery aluminum foil according to claim 1, characterized in that, In step (4), there are three cold rolling passes, and the thickness of the cold-rolled finished product is 0.21~0.25mm.