1XXX aluminum alloy for high-strength power battery foil and preparation method of 1XXX aluminum alloy

Abstract

The invention relates to a 1XXX aluminum alloy for a high-strength power battery foil and a preparation method of the 1XXX aluminum alloy, the 1XXX aluminum alloy comprises the following components in percentage by mass: 0.05-0.12% of Si, 0.2-0.4% of Fe, 0.08-0.15% of V, 0.01-0.02% of Ti and the balance of Al and other inevitable impurities, and Fe / V is greater than or equal to 2; when Si > = 0.1%, V > = 0.1%. The aluminum foil with good plasticity and ultrahigh strength is obtained, the tensile strength of the aluminum foil is larger than or equal to 290 MPa, the ductility of the aluminum foil is larger than or equal to 2.5%, and the requirements of a lithium ion power battery current collector can be met.

Description

Technical Field

[0001] The present invention relates to the field of aluminum alloy preparation, and in particular to a 1XXX aluminum alloy for high-strength power battery foil and a preparation method thereof. Background Art

[0002] The rapid development of the new energy vehicle industry has led to a rapid growth in the scale of lithium-ion power batteries in recent years, which has driven the demand for aluminum foil for battery current collectors. Driven by the continuous increase in battery specific energy density, the thickness of battery foil has continued to decrease. With the technical requirements of faster and faster coating speeds and wider coating widths, in order to prevent the aluminum foil from breaking during coating, the foil needs to have higher strength to reduce the risk of breaking caused by thinning.

[0003] Chinese patent CN202111537974.X discloses a high elongation 1060 alloy battery aluminum foil production process, in which the battery aluminum foil composition is Si≤0.1wt%, Fe≤0.2wt%, Cu: 0.05-0.06wt%, Ti: 0.01-0.03wt%. The basic process flow is: smelting and casting to produce a strip, cold rolling to 2.5mm annealing: heating from room temperature to 580℃×4-5h for 5-7h, then cooling to 470℃×3h for 0.5-2h; then cold rolling to 0.52mm, rolling to a thickness of 0.013-0.015mm; finally annealing: heating from room temperature to 400℃×5-25h for 2-5h, then cooling to 200℃×10-45h for 2-5h, and then cooling to room temperature for 2-15h. This patent adopts the casting and rolling process for production, does not involve the V element, and has strict requirements on the control of Fe content. The tensile strength of the prepared aluminum foil is ≥200MPa and the elongation is ≥3.5%.

[0004] Chinese patent CN202011137836.8 discloses a high-performance aluminum foil for lithium-ion batteries and a production method. The aluminum foil composition includes Si≤0.1wt%, Fe: 0.15~0.3wt%, Cu: 0.08~0.15wt%, Mn≤0.01wt%, Mg≤0.03wt%, Zn≤0.03wt%, Ti: 0.02~0.03wt%, V≤0.03wt%. The basic process flow is: melt the ingot, hot roll it after annealing (520~560℃×10~15h), and the rolling temperature is 480~530℃; then cold roll it to 0.22~0.3mm, and finally roll the foil to 8~20μm and cut it into finished products. The patent adopts the hot rolling blanking path for production, and does not mention the control effect of the V element and its content range. The tensile strength of the prepared aluminum foil is 254MPa.

[0005] Chinese patent CN201710244163.8 discloses high-performance 1230A alloy aluminum foil for lithium-ion batteries and its preparation method. The aluminum foil composition includes Si: 0.1-0.2wt%, Fe: 0.35-0.5wt%, Cu: 0.01-0.1wt%, Mn≤0.05wt%, Mg≤0.05wt%, Zn≤0.01wt%, Ti: 0.01-0.03wt%. The basic process flow is: 7±0.2mm strip is smelted and cast, and annealed: at 260℃×3h, heated to 530℃×5h, then cooled to 420℃×3h, cooled for 2h and then taken out of the furnace; cold rolled to 0.42mm, cooled for 12h and then cold rolled to 0.18mm; finally, the foil is rolled to 0.0012-0.02mm. This patent adopts the casting and rolling process for production, does not involve the V element, and the prepared aluminum foil has a tensile strength of 235-245 MPa and an elongation of 3.3-4.2%.

[0006] Chinese patent CN202010802903.7 discloses an aluminum foil for 1235D lithium battery and its preparation method. The aluminum foil composition includes Si: 0.01-0.25wt%, Fe: 0.41-0.47wt%, Cu: 0.14-0.2wt%, Mn: 0.01-0.04wt%, Mg: 0.01-0.03wt%, Zn: 0.01-0.05wt%, Ti: 0.01-0.03wt%, V: 0.01-0.05wt%. The basic process flow is: 7-8mm strip billet is smelted and cast, and cold rolled to a thickness of 1.5-1.8mm; during the retreat: the material temperature is 330-380℃×2h, and the furnace temperature drops to 300±20℃ when the 1 / 2 furnace door is opened and discharged; then cold rolled to 0.36mm, and finally foil rolled, slit, and corona are used to obtain the finished aluminum foil. This patent adopts the casting and rolling process for production, and does not mention the control effect of the V element and its content range. It contains a higher Cu content to improve the alloy properties. The tensile strength of the prepared aluminum foil is ≥235MPa and the elongation is ≥2%. Summary of the invention

[0007] The object of the present invention is to provide a 1XXX aluminum alloy for high-strength power battery foil and a preparation method thereof, which ensures that the 1XXX aluminum alloy has high strength and good plasticity; the prepared aluminum foil has ultra-high strength, a tensile strength of ≥290MPa, and an elongation of ≥2.5%, which can meet the requirements of lithium-ion power battery current collectors.

[0008] To achieve the above object, the technical solution of the present invention is:

[0009] A 1XXX aluminum alloy for high-strength power battery foil, the composition mass percentage of which is: Si: 0.05-0.12%, Fe: 0.2-0.4%, V: 0.08-0.15%, Ti: 0.01-0.02%, the balance includes Al and other inevitable impurities, and also needs to meet the following requirements at the same time:

[0010] Fe / V≥2;

[0011] When Si ≥ 0.1%, V ≥ 0.1%.

[0012] Further, the balance is Al and other inevitable impurities.

[0013] Furthermore, the aluminum alloy further includes one or two of Mn: 0.01-0.1% and Cr: 0.01-0.1%, and satisfies Mn+Cr≤0.1%.

[0014] Preferably, the amount of the granular α-AlFeSi, AlV compound is 10-20%.

[0015] Preferably, the amount of dispersed α-AlFeSi and AlV precipitated phases is 75% or more.

[0016] Preferably, the amount of the Al3Fe precipitated phase is ≤5%.

[0017] Furthermore, the aluminum alloy further includes one or two of Mn: 0.01-0.1% and Cr: 0.01-0.1%, and satisfies Mn+Cr≤0.1%.

[0018] Preferably, the aluminum alloy metallographic structure is a recrystallized grain structure, on which granular α-AlFeSi, α-AlFeMnSi, AlV compounds, as well as dispersed α-AlFeSi, AlFeMnSi, AlV precipitation phases and a small amount of Al3Fe precipitation phase are distributed.

[0019] Preferably, the amount of the granular α-AlFeSi, α-AlFeMnSi, AlV compound is 10-20%.

[0020] Preferably, the amount of the dispersedly distributed α-AlFeSi, AlFeMnSi, and AlV precipitated phases is 75% or more.

[0021] Preferably, the amount of the Al3Fe precipitated phase is ≤5%.

[0022] The aluminum alloy metallographic structure of the present invention is a recrystallized grain structure, on which granular α-AlFeSi, α-AlFeMnSi, AlV compounds, dispersed α-AlFeSi, AlFeMnSi, AlV precipitation phases and a small amount of Al3Fe precipitation phase are distributed, wherein the amount of granular α-AlFeSi, α-AlFeMnSi, AlV compounds is 10-20%, the amount of dispersed α-AlFeSi, AlFeMnSi, AlV precipitation phases is 75% or more, and the amount of Al3Fe precipitation phase is less than 5%.

[0023] In the composition design of the 1XXX aluminum alloy for high-strength power battery foil of the present invention:

[0024] Si and Fe are the main elements in 1XXX aluminum alloys. The second phase formed by Si and Fe can serve as a recrystallization nucleation point, which is conducive to obtaining fine annealing grains; the dispersed phase formed by precipitation can hinder dislocation movement and improve strength. If the Si and Fe content is too low, the purity requirements of raw materials will be increased, which will increase costs; if the content is too high, coarse compounds are easily formed, which will have a negative impact on the elongation and pinhole control of the material. Therefore, the present invention controls the Si content to 0.05-0.12wt%, and controls the Fe content to 0.2-0.4wt%.

[0025] V, adding an appropriate amount of V can make V dissolved in the aluminum matrix as much as possible. The V element dissolved in the matrix can disperse and precipitate fine AlV phase during intermediate annealing, play a dispersion strengthening role, and help refine the annealing grains. At the same time, a small amount of V can also be dissolved in AlFe and α-AlFeSi compounds, which helps to promote the increase in the number of AlFe and α-AlFeSi phases precipitated during intermediate annealing, and promote further improvement of strength through dispersion strengthening. Moreover, when the Si content exceeds 0.1wt%, the precipitation of α-AlFeSi phase is likely to occur in the high-temperature annealing stage, reducing the precipitation amount of α-AlFeSi phase during intermediate annealing. The α-AlFeSi phase precipitated in the high-temperature annealing stage will grow and reduce the dispersion strengthening effect; therefore, when the Si content exceeds 0.1wt%, V is controlled ≥ 0.1wt%, and the addition of V can inhibit the precipitation of α-AlFeSi phase in the high-temperature annealing stage, which is beneficial to increase the precipitation amount during intermediate annealing and improve the dispersion strengthening effect. The V element content is low, the precipitated dispersed phase is small, and the strengthening effect is negligible. If the content is too high, coarse compounds are easily formed during casting and rolling. The coarse compounds are not easy to break and are left in the subsequent aluminum foil, which is not conducive to the elongation and pinhole control of the aluminum foil. Therefore, the present invention controls the V content to be 0.08-0.15wt%.

[0026] At the same time, it is also necessary to control Fe / V (mass ratio) ≥ 2 to avoid excessive V content to form coarse AlV compounds, which is not conducive to the elongation and pinhole control of aluminum foil.

[0027] Ti, a proper amount of Ti can refine the grains of the casting strip and improve the material processing performance. Therefore, the present invention controls the Ti content to be 0.01-0.02wt%.

[0028] Mn, a proper amount of Mn can change the type and morphology of the Fe-containing phase, forming α-AlFeMnSi compound particles, which is beneficial to reduce the adverse effects of Fe-containing phase on elongation and pinhole control; at the same time, a certain AlFeMnSi dispersed phase can be formed during intermediate annealing to supplement dispersion strengthening. Too high a content will have an adverse effect on conductivity. Therefore, the present invention can selectively add and control the Mn content to 0.01-0.1wt%.

[0029] Cr, a proper amount of Cr can form a dispersed phase, supplement the dispersion strengthening and grain refinement effects. If the content is too high, it is easy to form coarse compounds during casting, which is not conducive to elongation and pinhole control. Therefore, the present invention can selectively add and control the Cr content to 0.01-0.1wt%.

[0030] The solid solution of Mn and Cr elements in the aluminum matrix will have an adverse effect on the electrical conductivity. When the addition amount of Mn and Cr is too much, it will promote the precipitation of α-AlFeSi phase in the high-temperature annealing stage, resulting in a reduction in precipitation during intermediate annealing, leading to a weakening of the dispersion strengthening effect. Therefore, the Mn+Cr content is controlled to be ≤0.1wt%.

[0031] The invention adds a small amount of Si and Fe elements on the basis of the traditional 1XXX aluminum alloy, combines the addition of a relatively high V element, and especially when Si is greater than or equal to 0.1%, strictly controls V greater than or equal to 0.1%, inhibits the precipitation of coarse α-AlFeSi in the high-temperature annealing stage, increases the amount of AlFe and α-AlFeSi precipitation phases during the intermediate annealing, and at the same time, controls Fe / V (mass ratio) greater than or equal to 2, combines the precipitation of dispersed and fine AlV phases, promotes the improvement of the aluminum alloy strength, and ensures the elongation of the product.

[0032] The method for preparing the 1XXX aluminum alloy for high-strength power battery foil of the present invention comprises the following steps:

[0033] 1) Melting according to the above composition, degassing and deslagging, and continuous casting into billets;

[0034] 2) First cold rolling and coiling;

[0035] 3) High temperature annealing

[0036] First, heat the mixture to 390-410°C at a heating rate of 70-100°C / h, then heat the mixture to 540-580°C at a heating rate of 20-40°C / h and keep the mixture at that temperature for 4-12 hours. After the temperature is kept at that temperature, the mixture is cooled to room temperature in an air-cooled manner.

[0037] 4) Second cold rolling and coiling;

[0038] 5) Intermediate annealing

[0039] Heat to 300-380°C at a heating rate of 30-50°C / h and keep warm for 4-10h;

[0040] 6) The third cold rolling, hard foil blank.

[0041] Preferably, in step 1), the thickness of the blank is 5 to 8 mm.

[0042] Preferably, in step 1), the hydrogen content of the alloy melt obtained by smelting after degassing is not greater than 0.11 ml / 100 gAl.

[0043] Preferably, the total reduction rate of the first cold rolling is ≥50%, and the thickness of the billet after the first cold rolling is 2-4 mm; the total reduction rate of the second cold rolling is ≥60%, and the thickness of the billet after the second cold rolling is 0.6-1.5 mm; the total reduction rate of the third cold rolling is 60-80%, and the thickness of the billet after the third cold rolling is 0.2-0.4 mm.

[0044] The present invention also provides a high-strength power battery foil, which is prepared by using the aluminum foil blank through foil rolling, slitting and cleaning processes.

[0045] The battery foil of the present invention has a tensile strength of ≥290MPa and an elongation of ≥2.5%.

[0046] In the method for preparing the 1XXX aluminum alloy for high-strength power battery foil of the present invention:

[0047] The present invention adopts continuous casting method (continuous casting and rolling or continuous casting and rolling), and utilizes its rapid solidification characteristics to dissolve elements such as Si, Fe, and V in the alloy matrix to the greatest extent. First, it can prevent the formation of coarse compounds (AlFe, AlV, etc.), form a second phase with a smaller size, and reduce the adverse effects of coarse compounds on elongation and pinhole control; second, it is conducive to the alloy elements to exist in the form of dispersed phases after subsequent intermediate annealing, thereby improving the strength of the alloy. If semi-continuous casting is used to prepare the ingot, the melt solidification speed is relatively slow. Due to the limited solid solution, a large part of the 0.08-0.15wt% V element contained in the present invention will precipitate in the relatively slow solidification process and exist in the ingot as coarse AlV compounds. In addition, under this condition, Fe and Si elements are also easy to form coarse AlFe and AlFeSi compounds, which is not conducive to material properties and aluminum foil pinhole control.

[0048] The alloy melt is degassed and slag-removed in the furnace and online to control the hydrogen content in the melt to no more than 0.11ml / 100gAl, which can reduce the risk of pinholes in the subsequent aluminum foil.

[0049] The present invention adopts high temperature annealing:

[0050] 1) First, the temperature is raised to 390-410°C at a faster heating rate of 70-100°C / h, which can reduce the precipitation of α-AlFeSi and AlV compounds during the heating process. If the heating rate is slow, a large amount of α-AlFeSi and AlV compounds are likely to precipitate in this process. The precipitated phase at this stage will grow in the subsequent higher temperature stage, resulting in a decrease in the solid solubility of Fe, Si, and V elements in the alloy, resulting in a decrease in the amount of precipitation of α-AlFeSi and AlV compounds in the subsequent intermediate annealing, and the size of the precipitated α-AlFeSi and AlV compounds will grow, reducing the dispersion strengthening effect, thereby bringing about an adverse effect on the strength; at the same time, the compound transformation is limited in the temperature range below 410°C, and a faster heating rate can improve production efficiency without adversely affecting the alloy structure.

[0051] 2) Then heat up to 540-580℃ at 20-40℃ / h and keep warm for 4-12h, which is beneficial to the solid solution of V, Fe, Si and other elements in the alloy, reduces the precipitation of α-AlFeSi phase at this stage, prevents precipitation and growth due to improper temperature control, and brings adverse effects on the subsequent performance of aluminum foil; promotes the full transformation of the compounds formed during the casting and rolling process, improves the uniformity of the structure in the material, and ensures the alloy performance; and annealing to eliminate stress is beneficial to subsequent rolling and improves plate shape control. If the temperature is kept below 540℃, for the alloy of the present invention, a large amount of α-AlFeSi and AlV compounds will precipitate. The precipitation at this stage will firstly reduce the solid solubility of Fe, Si, and V elements in the alloy, which is not conducive to the precipitation amount of subsequent intermediate annealing, and secondly, the precipitated phase is prone to growth and coarsening during the insulation process at this stage, resulting in the weakening of the dispersion strengthening effect of the precipitated phase. Keeping warm at a temperature above 580 is likely to cause the coarsening of annealed grains, which is not conducive to the surface and elongation of the subsequent aluminum foil. For the alloy of the present invention, if the high temperature annealing is not carried out in the staged control of the present scheme, and the annealing is directly carried out by heating to 500-580°C at a relatively slow speed, or after annealing and keeping at 560-580°C, keeping at 380-460°C, or annealing at 460-480°C, more Fe, Si, and V elements will be precipitated during the annealing process at this stage, which is not conducive to precipitation in the subsequent intermediate annealing.

[0052] Add intermediate annealing between the second cold rolling and the third cold rolling: heat to 300-380℃ at a heating rate of 30-50℃ / h and keep warm for 4-10h. Intermediate annealing promotes the solid-dissolved Si, Fe, V, Mn, Cr and other elements in the alloy to exist in the alloy matrix in the form of dispersed phase, which is conducive to the precipitation of more dispersed phases such as AlFeSi and AlV, and reduces the growth of Al3Fe needle-like phase as much as possible, plays the role of dispersion strengthening and grain refinement, so that the strength can be further improved without adversely affecting the elongation; at the same time, the precipitation of the precipitated phase can also ensure that the aluminum alloy has high electrical conductivity. If intermediate annealing is not performed or the intermediate annealing process is improper, the solid-dissolved elements cannot be effectively precipitated, and the role of dispersion strengthening and grain refinement cannot be played. If the intermediate annealing temperature is too high, the Al3Fe needle-like phase will grow, and the precipitation of AlFeSi, AlV, etc. will be limited, which will have an adverse effect on the elongation, strength and pinhole control of the aluminum foil. If the intermediate annealing temperature is lower than 300℃, the recrystallization will be insufficient and the precipitation time will be too long. If the intermediate annealing time is lower than 4h, the precipitation will be insufficient and the expected dispersion strengthening effect will not be achieved. If the annealing time is longer than 10h, the recrystallized grains and precipitation phases will coarsen, which is not conducive to the performance.

[0053] The total reduction rate of the first cold rolling is ≥50%, and the thickness of the billet after the first cold rolling is 2-4mm: the alloy has a certain amount of energy storage through cold rolling, which is conducive to the occurrence of high-temperature annealing recrystallization. If the cast plate is not cold rolled or the cold rolling rate is less than 50%, the energy storage is low, which makes it difficult to recrystallize during annealing, which is not conducive to subsequent rolling, or requires a higher temperature for recrystallization to occur, which is easy to cause coarse recrystallized grains, which has an adverse effect on the subsequent aluminum foil surface and elongation, and is also not conducive to energy consumption control.

[0054] The total reduction rate of the second cold rolling is ≥60%, and the thickness of the billet after the second cold rolling is 0.6-1.5mm: the alloy has a certain amount of energy storage through cold rolling, which is conducive to the occurrence of intermediate annealing recrystallization and the acquisition of finer recrystallized grains. If the cold rolling rate is less than 60%, the energy storage is low, which makes it difficult for recrystallization to occur during annealing, which is not conducive to subsequent rolling; or a higher temperature is required for recrystallization to occur, which is not conducive to the precipitation of the annealing process, and it is easy to cause coarse recrystallized grains, which has an adverse effect on the subsequent aluminum foil surface, strength, and elongation.

[0055] The total reduction rate of the third cold rolling is 60-80%, and the thickness of the billet after the third cold rolling is 0.2-0.4mm: this thickness is convenient for the subsequent rolling of aluminum foil. If the thickness is too large, it will exceed the capacity of the aluminum foil rough rolling entrance equipment and cannot be rolled; if the thickness is less than 0.2mm, it will exceed the rolling capacity of the cold rolling mill, and it will not be able to be rolled or cause poor plate shape. The cold rolling rate is controlled at 60-80%, so that the aluminum foil batch has a suitable strength and elongation combination, which is conducive to the subsequent rolling of the aluminum foil and the control of the performance of the finished product. If the cold rolling rate is too high, the billet strength will be too high, so that the aluminum foil will break during rolling and the elongation will be low. If the cold rolling rate is too low, the strength of the aluminum foil will be low.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] 1. In terms of composition design, the present invention, on the basis of conventional 1XXX aluminum alloy, adds a relatively high V element, and when Si≥0.1%, strictly controls V≥0.1%, which can inhibit the precipitation and coarsening of α-AlFeSi phase in the high-temperature annealing stage, thereby promoting the precipitation of AlFe and α-AlFeSi phases in the intermediate annealing stage; at the same time, the Fe / V (mass ratio) is controlled to be ≥2, combined with the precipitation of dispersed fine AlV phase, and the precipitation of the second phase and dispersed phase (AlFeSi, AlFe, AlV, etc.) formed by elements such as Al, Fe, Si, and V is utilized to refine the recrystallized grains, and the hindering effect of the dispersed phase on the dislocation movement is used to further improve the strength of the alloy on the basis of work hardening, without adversely affecting the elongation and electrical conductivity of the alloy, so that the tensile strength of the battery foil prepared using the 1XXX aluminum alloy is ≥290MPa; while the tensile strength of the battery foil prepared by the existing 1XXX aluminum alloy can only reach about 250MPa at most.

[0058] 2. On the basis of component design, the present invention reduces the precipitation of α-AlFeSi and AlV compounds during the heating process by controlling a faster heating rate in the high-temperature annealing stage, and prevents the precipitation and coarsening of α-AlFeSi and AlV compounds during the heat preservation stage in combination with a higher annealing temperature, thereby ensuring the solid solubility of the alloy elements and ensuring that the dissolved Si, Fe, V, Mn, Cr and other elements (especially the V element) are fully precipitated during the subsequent intermediate annealing process, which is conducive to the precipitation of more dispersed phases such as AlFeSi and AlV, while reducing the growth of the Al3Fe needle-like phase as much as possible, thereby enhancing the effects of dispersion strengthening, grain refinement and electrical conductivity, thereby improving the strength of the aluminum alloy without adversely affecting the elongation and electrical conductivity. DETAILED DESCRIPTION

[0059] The present invention is further illustrated by the following examples, but this is not a limitation of the present invention. Those skilled in the art may make modifications or improvements based on the basic idea of ​​the invention, but as long as they do not deviate from the basic idea of ​​the present invention, they are all within the scope of the present invention.

[0060] The chemical composition of the aluminum alloy of the embodiment of the present invention and the comparative example is shown in Table 1, and the remainder of the composition includes Al and other inevitable impurities. The process parameters of the preparation method of the embodiment of the present invention are shown in Table 2, and the properties of the prepared aluminum foil are shown in Table 3.

[0061] Preparation process of comparative example 4:

[0062] Industrial pure aluminum ingots and various master alloys were melted, degassed and deslagged according to the composition ratio of Example 3 in Table 1, and then semi-continuously cast into flat ingots. The hydrogen content of the alloy melt after degassing was 0.11 ml / 100 gAl. The flat ingots were subjected to high temperature annealing treatment: the temperature was raised to 400°C at a heating rate of 100°C / h, then raised to 580°C at a rate of 20°C / h and kept at this temperature for 12 hours, then cooled to 510°C and hot rolled to prepare a 6 mm thick billet, and the strip was cold rolled to 0.4 mm to obtain a hard foil billet.

[0063] It can be seen from the data in Table 3 that the aluminum foil obtained in Examples 1-6 of the present invention has a tensile strength of not less than 290 MPa, an elongation of more than 2.5%, and a resistivity of ≤3.2 μΩ·cm, and can be used for power battery current collectors. It can meet the demand for further thinning of the aluminum foil of the power battery current collector for increased strength, and reduce the risk of broken tape during coating.

[0064] Comparative Example 1 did not add V, and the same process as Example 1 was used to prepare the aluminum foil, and the strength of the aluminum foil was relatively low.

[0065] In Comparative Example 2, excessive amounts of Si, V, and Cr are added, and Fe / V≤2. Although the same process as Example 3 is used, the elongation of the prepared aluminum foil is low and the resistance is high.

[0066] The ingredients of Comparative Example 3 are the same as those of Example 1, and no annealing process is added during cold rolling. The strength of the prepared aluminum foil is relatively low and the resistance is relatively high.

[0067] The ingredients of Comparative Example 4 are the same as those of Example 3, but the process is different (semi-continuous casting is used for billet making, and cold rolling is performed without annealing process). The strength and elongation of the prepared aluminum foil are relatively low, and the resistance is relatively high.

[0068]

[0069]

[0070]

Claims

1. A 1XXX aluminum alloy for high-strength power battery foil, the composition mass percentage of which is: Si: 0.05-0.12%, Fe: 0.2-0.4%, V: 0.08-0.15%, Ti: 0.01-0.02%, the balance includes Al and other inevitable impurities, and also needs to meet the following requirements: Fe / V≥2; When Si ≥ 0.1%, V ≥ 0.1%.

2. The 1XXX aluminum alloy for high-strength power battery foil according to claim 1, characterized in that: The balance is Al and other inevitable impurities.

3. The 1XXX aluminum alloy for high-strength power battery foil according to claim 1 or 2, characterized in that: The aluminum alloy metallographic structure is a recrystallized grain structure, on which granular α-AlFeSi and AlV compounds, dispersed α-AlFeSi and AlV precipitation phases and a small amount of Al3Fe precipitation phase are distributed.

4. The 1XXX aluminum alloy for high-strength power battery foil according to claim 3, characterized in that: The amount of the granular α-AlFeSi and AlV compounds is 10-20%.

5. The 1XXX aluminum alloy for high-strength power battery foil according to claim 3, characterized in that: The amount of dispersed α-AlFeSi and AlV precipitated phases is 75% or more.

6. The 1XXX aluminum alloy for high-strength power battery foil according to claim 3, characterized in that: The amount of the Al3Fe precipitated phase is ≤5%.

7. The 1XXX aluminum alloy for high-strength power battery foil according to claim 1 or 2, characterized in that: The aluminum alloy further comprises one or two of Mn: 0.01-0.1% and Cr: 0.01-0.1%, and satisfies Mn+Cr≤0.1%.

8. The 1XXX aluminum alloy for high-strength power battery foil according to claim 7, characterized in that: The aluminum alloy metallographic structure is a recrystallized grain structure, on which granular α-AlFeSi, α-AlFeMnSi, AlV compounds, dispersed α-AlFeSi, AlFeMnSi, AlV precipitation phases and a small amount of Al3Fe precipitation phase are distributed.

9. The 1XXX aluminum alloy for high-strength power battery foil according to claim 8, characterized in that: The amount of the granular α-AlFeSi, α-AlFeMnSi, AlV compound is 10-20%.

10. The 1XXX aluminum alloy for high-strength power battery foil according to claim 8, characterized in that: The amount of the dispersedly distributed α-AlFeSi, AlFeMnSi and AlV precipitated phases is 75% or more.

11. The 1XXX aluminum alloy for high-strength power battery foil according to claim 8, characterized in that: The amount of the Al3Fe precipitated phase is ≤5%.

12. The method for preparing the 1XXX aluminum alloy for high-strength power battery foil according to any one of claims 1 to 11, characterized in that: The steps include: 1) Melting the components according to claim 1, 2 or 7, and performing degassing and deslagging treatments, and continuously casting into billets; 2) First cold rolling and coiling; 3) High temperature annealing First, heat the mixture to 390-410°C at a heating rate of 70-100°C / h, then heat the mixture to 540-580°C at a heating rate of 20-40°C / h and keep the mixture at that temperature for 4-12 hours. After the temperature is kept at that temperature, the mixture is cooled to room temperature in an air-cooled manner. 4) Second cold rolling and coiling; 5) Intermediate annealing Heat to 300-380°C at a heating rate of 30-50°C / h and keep warm for 4-10h; 6) The third cold rolling, hard foil blank.

13. The preparation method according to claim 12, characterized in that: In step 1), the thickness of the blank is 5 to 8 mm.

14. The preparation method according to claim 12 or 13, characterized in that: In step 1), the hydrogen content of the alloy melt obtained by smelting is not more than 0.11 ml / 100 gAl after degassing.

15. The preparation method according to claim 12, characterized in that: The total reduction rate of the first cold rolling is ≥50%, and the thickness of the billet after the first cold rolling is 2-4 mm; the total reduction rate of the second cold rolling is ≥60%, and the thickness of the billet after the second cold rolling is 0.6-1.5 mm; the total reduction rate of the third cold rolling is 60-80%, and the thickness of the billet after the third cold rolling is 0.2-0.4 mm.

16. A high-strength power battery foil, characterized in that: The aluminum foil blank is prepared by using the aluminum foil blank described in claims 1 to 11 or the aluminum foil blank obtained by the preparation method described in claims 12 to 15 through foil rolling, slitting and cleaning steps.

17. The high-strength power battery foil according to claim 16, characterized in that: The battery foil has a tensile strength of ≥290 MPa and an elongation of ≥2.5%.

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