High-performance current collector battery aluminum foil and preparation method and application thereof

Abstract

This invention discloses a high-performance current collector battery aluminum foil, its preparation method, and its application, belonging to the field of battery material technology. The high-performance current collector battery aluminum foil contains 0.30%~0.45% Fe, 0.30%~0.32% Si, 0.01%~0.04% Cu, ≤0.004% Ti, ≤0.004% Mn, ≤0.006% Mg, ≤0.004% V, ≤0.006% Zn, and 0.02%~0.25% Ce, with the balance being Al and unavoidable impurities. By doping with a specific proportion of Ce (by mass percentage), the aluminum foil's grain size is refined, purified, and its microstructure homogenized, simultaneously improving its toughness and conductivity. This solves the problem of poor synergy between strength, toughness, and conductivity in traditional 1060 series aluminum foil, resulting in a current collector battery aluminum foil possessing high tensile strength, high elongation, and high conductivity.

Description

Technical Field

[0001] This invention relates to the field of battery materials technology, and more specifically, to a high-performance current collector battery aluminum foil, its preparation method, and its application. Background Technology

[0002] In the internal structure of a battery, aluminum foil, as the current collector, plays a crucial role in supporting the positive electrode active material and transmitting current. 1060 series aluminum alloys are often used as current collector foil materials due to their high purity and good conductivity; however, pure 1060 aluminum foil has relatively low tensile strength, making it difficult to meet the requirements of high-density power batteries.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a high-performance current collector battery aluminum foil, its preparation method and application, in order to solve or improve the above-mentioned technical problems.

[0005] This invention can be implemented as follows: In a first aspect, the present invention provides a high-performance current collector battery aluminum foil, which, by mass percentage, contains 0.30%~0.45% Fe, 0.30%~0.32% Si, 0.01%~0.04% Cu, ≤0.004% Ti, ≤0.004% Mn, ≤0.006% Mg, ≤0.004% V, ≤0.006% Zn, and 0.02%~0.25% Ce, with the balance being Al and unavoidable impurities.

[0006] In an optional embodiment, the high-performance current collector aluminum foil contains 0.32%~0.45% Fe, 0.30%~0.32% Si, 0.01%~0.04% Cu, 0.001%~0.003% Ti, 0.002% Mn, 0.003%~0.006% Mg, 0.001% V, 0.003%~0.006% Zn, and 0.044%~0.23% Ce, with the balance being Al and unavoidable impurities.

[0007] In an optional embodiment, the high-performance current collector aluminum foil also has at least one of the following characteristics: Feature 1: The tensile strength of high-performance current collector aluminum foil in the cold-rolled state is ≥160MPa; Feature 2: The yield strength of high-performance current collector aluminum foil in the cold-rolled state is ≥145MPa; Feature 3: The elongation after fracture of high-performance current collector aluminum foil in the cold-rolled state is ≥4%; Feature 4: The conductivity of high-performance current collector aluminum foil in the cold-rolled state is ≥44% IACS; Feature 5: The tensile strength of the high-performance current collector battery aluminum foil in the annealed state is ≥143MPa; Feature 6: The yield strength of high-performance current collector aluminum foil in the annealed state is ≥128MPa; Feature 7: The elongation after fracture of high-performance current collector aluminum foil in the annealed state is ≥2%; Feature 8: The conductivity of high-performance current collector aluminum foil in the annealed state is ≥47% IACS.

[0008] Secondly, the present invention provides a method for preparing a high-performance current collector battery aluminum foil as described in any of the foregoing embodiments, comprising the following steps: Raw materials that meet the preset composition and ratio of aluminum foil are smelted to obtain aluminum alloy melt; the aluminum alloy melt is then refined. The refined aluminum alloy melt is degassed and filtered online, and the filtered aluminum melt is cast to obtain aluminum alloy ingots. The aluminum alloy ingot is homogenized and its surface is milled to obtain a homogenized ingot. The homogenized ingot is hot rolled in multiple passes to obtain the aluminum foil blank for current collector batteries; The aluminum foil blank for current collector batteries is subjected to intermediate annealing. The aluminum foil blank for current collector batteries after intermediate annealing is cooled and then subjected to multiple cold rolling passes to obtain cold-rolled finished aluminum foil. The cold-rolled finished aluminum foil is annealed.

[0009] In an optional embodiment, the amount of aluminum molten salt composite refining agent used in the refining process is 0.2wt% to 0.3wt% of the aluminum alloy melt.

[0010] In an optional embodiment, the aluminum molten salt composite refining agent contains, by mass percentage, 20%~30% Na, ≤5% K, 13%~23% Cl, 6%~12% Si, 10%~18% F, 15%~25% O, 5%~15% Ca and ≤5% S.

[0011] In an optional implementation, online degassing is performed at 710℃~730℃ for 15min~30min, using argon as the degassing medium at a flow rate of 0.2m³ / min. 3 / min~0.5m 3 / min; And / or, the filtration adopts a three-stage filtration method using ceramic filters.

[0012] In an optional embodiment, the homogenization treatment temperature is 570℃~590℃, and the holding time is 7h~8h; And / or, the intermediate annealing temperature is 490℃~510℃, and the holding time is 140min~160min; And / or, the annealing temperature of the cold-rolled finished aluminum foil is 190℃~210℃, and the holding time is 5h~7h.

[0013] In an optional embodiment, the temperature of the multi-pass hot rolling is 490℃~510℃, and the holding time for each pass is 10min~20min.

[0014] In an optional implementation, the number of hot rolling passes in multi-pass hot rolling is 4 to 6.

[0015] In an optional implementation, a soap-based emulsion is added during the multi-pass hot rolling process.

[0016] In an optional embodiment, the soap-based emulsion includes fatty acids and organic amines.

[0017] In an optional implementation, the number of cold rolling passes in multi-pass cold rolling is 4 to 9.

[0018] In an optional embodiment, after cold rolling, the annealing temperature of the finished cold-rolled aluminum foil is 190℃~210℃, and the holding time is 5h~7h.

[0019] Thirdly, the present invention provides a battery containing a high-performance current collector aluminum foil according to any of the foregoing embodiments.

[0020] The beneficial effects of this invention include: This invention optimizes the alloy composition design and controls the addition ratio of the rare earth element Ce. Utilizing the purifying and refining effect of Ce on the aluminum alloy melt, Ce combines with Fe and Si elements to form novel compounds. This effectively improves the morphology and size of the trace coarse AlFeSi phases in the alloy, while simultaneously hindering dislocation movement and grain boundary migration, achieving grain refinement and strengthening. By synergistically optimizing key process parameters such as homogenization, hot rolling, annealing, and cold rolling, the invention ensures the strength advantage brought by the increased alloying degree, while eliminating work hardening and adjusting the microstructure through intermediate and finished annealing, avoiding difficulties in rolling due to excessive strength. The solution provided by this invention solves the problem of poor synergy between strength, toughness, and conductivity in traditional 1060 series aluminum foil, obtaining current collector battery aluminum foil with high tensile strength, high elongation, and high conductivity. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0022] The following is a detailed description of the high-performance current collector battery aluminum foil, its preparation method, and its application provided by the present invention.

[0023] This invention provides a high-performance current collector battery aluminum foil, which, by mass percentage, contains 0.30%~0.45% Fe, 0.30%~0.32% Si, 0.01%~0.04% Cu, ≤0.004% Ti, ≤0.004% Mn, ≤0.006% Mg, ≤0.004% V, ≤0.006% Zn, and 0.02%~0.25% Ce, with the balance being Al and unavoidable impurities.

[0024] In some alternative embodiments, the Fe content in the high-performance current collector aluminum foil can be 0.30%, 0.32%, 0.35%, 0.38%, 0.40%, 0.42%, or 0.45%, or other values ​​within the range of 0.30% to 0.45%.

[0025] The Si content in the aluminum foil of high-performance current collector batteries can be 0.30%, 0.31%, or 0.32%, or other values ​​within the range of 0.30% to 0.32%.

[0026] The Cu content in the aluminum foil of high-performance current collector batteries can be 0.01%, 0.02%, 0.03%, or 0.04%, or other values ​​within the range of 0.01% to 0.04%.

[0027] The Ce content in the aluminum foil of high-performance current collector batteries can be 0.02%, 0.05%, 0.10%, 0.15%, 0.20%, or 0.25%, or other values ​​within the range of 0.02% to 0.25%.

[0028] The contents of Ti, Mn and V in the aluminum foil of high-performance current collector batteries can be independently 0.004%, 0.003%, 0.002% or 0.001%, or other values ​​within the range of ≤0.004%.

[0029] The content of Mg and Zn in the aluminum foil of high-performance current collector batteries can be independently 0.006%, 0.005%, 0.004%, 0.003%, 0.002% or 0.001%, or other values ​​within the range of ≤0.006%.

[0030] This invention optimizes the alloy composition design, controlling the addition ratio of the rare earth element Ce to be 0.02%~0.25%. Utilizing the purifying and refining effect of Ce on the aluminum alloy melt, Ce combines with Fe and Si elements to form novel compounds, effectively improving the morphology and size of the trace coarse AlFeSi phase in the alloy. Simultaneously, it hinders dislocation movement and grain boundary migration, achieving grain refinement and strengthening. If the Ce content is below 0.02%, the effect is not significant; if the Ce content is above 0.25%, it easily leads to the aggregation of rare earth elements, forming coarse second phases, which reduces the alloy's performance. Furthermore, it should be emphasized that compared to other rare earth elements such as La, Y, and Sc, the specific Ce doping in this application has the advantages of abundant reserves in the Earth's crust, low economic cost, and superior purification effect on the aluminum alloy melt compared to other rare earth elements.

[0031] In some preferred embodiments, the high-performance current collector aluminum foil contains 0.32%~0.45% Fe, 0.30%~0.32% Si, 0.01%~0.04% Cu, 0.001%~0.003% Ti, 0.002% Mn, 0.003%~0.006% Mg, 0.001% V, 0.003%~0.006% Zn, and 0.044%~0.23% Ce, with the balance being Al and unavoidable impurities. Within this preferred range, the high-performance current collector aluminum foil can have better tensile strength, elongation, and conductivity.

[0032] In some alternative implementations, the high-performance current collector aluminum foil has a tensile strength ≥160MPa in the cold-rolled state, such as 161MPa~168MPa.

[0033] In some alternative implementations, the high-performance current collector aluminum foil has a yield strength ≥145MPa in the cold-rolled state, such as 146MPa~151MPa.

[0034] In some alternative implementations, the high-performance current collector aluminum foil has an elongation at break of ≥4% in the cold-rolled state, such as 4.0% to 6.2%.

[0035] In some alternative implementations, the high-performance current collector aluminum foil has a conductivity ≥44% IACS in the cold-rolled state, such as 44.4% IACS to 51.2% IACS.

[0036] In some alternative implementations, the high-performance current collector aluminum foil has a tensile strength ≥143MPa in the annealed state, such as 143MPa~149MPa.

[0037] In some alternative implementations, the high-performance current collector aluminum foil has a yield strength ≥128MPa in the annealed state, such as 128MPa~137MPa.

[0038] In some alternative implementations, the high-performance current collector aluminum foil has an elongation at break of ≥2% in the annealed state, such as 2.0% to 4.5%.

[0039] In some alternative implementations, the high-performance current collector aluminum foil has a conductivity ≥47% IACS in the annealed state, such as 47% IACS to 52.1% IACS.

[0040] As mentioned above, the high-performance current collector battery aluminum foil provided by this invention has properties such as high tensile strength, high elongation and high conductivity.

[0041] Accordingly, the present invention also provides a method for preparing the above-mentioned high-performance current collector battery aluminum foil, comprising the following steps: S1: Melt the raw materials that meet the preset composition and ratio of aluminum foil to obtain aluminum alloy melt; refine the aluminum alloy melt.

[0042] In some optional embodiments, the amount of aluminum molten salt composite refining agent used in the refining process can be 0.2wt% to 0.3wt% of the aluminum alloy melt, such as 0.2wt%, 0.25wt%, or 0.3wt%, or other values ​​within the range of 0.2wt% to 0.3wt%.

[0043] In some optional embodiments, the aluminum molten salt composite refining agent may contain, by mass percentage, 20% to 30% (e.g., 20%, 25%, or 30%) of Na, ≤5% (e.g., 5%, 4%, 3%, 2%, or 1%) of K, 13% to 23% (e.g., 13%, 15%, 20%, or 23%) of Cl, 6% to 12% (e.g., 6%, 8%, 10%, or 12%) of Si, 10% to 18% (e.g., 10%, 12%, 15%, or 18%) of F, 15% to 25% (e.g., 15%, 20%, or 25%) of O, 5% to 15% (e.g., 5%, 10%, or 15%) of Ca, and ≤5% (e.g., 5%, 4%, 3%, 2%, or 1%) of S.

[0044] In some optional embodiments, the corresponding raw materials are weighed according to the preset composition and ratio of the aluminum foil and put into the melting furnace for melting. After complete melting, the aluminum alloy melt is stirred and refined. Specifically, high-purity aluminum ingots with a purity of 99.99 wt%, Al-Si master alloy, Al-Fe master alloy, and Al-Ce master alloy are used as raw materials, wherein the amount of Al-Ce master alloy added is determined according to the target Ce content. First, the melting furnace is heated to 770℃~790℃, and high-purity aluminum ingots are added and allowed to melt completely. When the furnace temperature drops to 730℃~750℃, Al-Si, Al-Fe, and Al-Ce master alloys are added. After the master alloys are completely melted, aluminum molten salt composite refining agent is added to stir and refine the aluminum alloy melt.

[0045] S2: The refined aluminum alloy melt is degassed and filtered online, and the filtered aluminum melt is cast to obtain aluminum alloy ingots.

[0046] In some optional embodiments, online degassing can be performed at 710℃~730℃ (e.g., 710℃, 720℃, or 730℃) for 15min~30min (e.g., 15min, 20min, 25min, or 30min). Argon gas can be used as the degassing medium, and the argon gas flow rate can be 0.2m³ / h. 3 / min~0.5m 3 / min (e.g., 0.2m) 3 / min, 0.3m 3 / min, 0.4m 3 / min or 0.5m 3 / min etc.).

[0047] In some alternative implementations, filtration can be performed using a three-stage ceramic filter system. The filter plate can be a two-stage ceramic foam filter plate with a pressure of 50 PPi + 60 PPi, and the third stage can be an RB-stage tubular filter.

[0048] In some optional embodiments, the refined aluminum alloy melt is transferred to a degassing box for online degassing; after degassing, it is filtered in three stages using a ceramic filter screen. After filtration, when the furnace temperature drops to 710°C~730°C, the melt is poured into a preheated metal mold and cast to obtain an aluminum alloy ingot (the thickness can be approximately 30mm for example).

[0049] S3: The aluminum alloy ingot is homogenized and its surface is milled to obtain a homogenized ingot.

[0050] In some optional implementations, the homogenization treatment temperature can be 570℃~590℃ (e.g., 570℃, 575℃, 580℃, 585℃ or 590℃, etc.), and the holding time can be 7h~8h (e.g., 7h, 7.5h or 8h, etc.).

[0051] In some optional embodiments, the aluminum alloy ingot is placed in a box-type resistance furnace or heating furnace and heated to 570°C~590°C at a heating rate of 8°C / min~10°C / min. The homogenization temperature is controlled at 570°C~590°C, and the holding time is 7h~8h. It is then cooled to room temperature using furnace cooling to eliminate component segregation and casting stress within the ingot. After homogenization, the surface of the ingot is milled using a milling machine. This milling removes the surface defect layer, ensuring that fractures due to surface defects do not occur during subsequent rolling. The thickness of the homogenized ingot after milling can, for example, be approximately 29mm, and the flatness of the ingot after milling can be ≤0.3mm / m, and the surface roughness Ra can be ≤5μm.

[0052] S4: The homogenized ingot is hot rolled in multiple passes to obtain the aluminum foil blank for current collector batteries.

[0053] In some alternative embodiments, the temperature of multi-pass hot rolling can be 490℃~510℃ (e.g., 490℃, 495℃, 500℃, 505℃ or 510℃, etc.), and the holding time for each pass can be 10min~20min (e.g., 10min, 15min or 20min, etc.).

[0054] In some alternative implementations, the number of hot rolling passes in multi-pass hot rolling can be 4 to 6, such as 4, 5 or 6.

[0055] In some optional embodiments, a soap-based emulsion may be added during the multi-pass hot rolling process, with the amount of soap-based emulsion added being 5% to 8%. The soap-based emulsion may exemplary include fatty acids (such as oleic acid) and organic amines (such as triethanolamine), with a volume ratio of fatty acids to organic amines of 1:1. Adding a soap-based emulsion during the hot rolling process can provide lubrication and cooling, prevent aluminum adhesion, and reduce abrasive wear on the rolls.

[0056] In some alternative implementations, the thickness of the current collector battery aluminum foil blank obtained after multiple hot rolling processes can be 2.6 mm to 2.9 mm.

[0057] In some optional embodiments, the milled homogenized ingot is placed in a box-type resistance furnace (preferably vertically to ensure uniform and sufficient heating of the rolled surface of the ingot), heated to 490°C~510°C, and held for 110min~130min; multi-pass hot rolling is performed using a two-roll mill, with a total of 4~6 hot rolling passes, each with a reduction of about 5mm; 5%~8% soap-based emulsion (a mixture of fatty acids and organic amines in a 1:1 volume ratio) is added during the multi-pass hot rolling process; the holding time for each pass can be 10min~20min, to obtain a current collector battery aluminum foil blank (the thickness can be exemplarily 2.7~2.9mm).

[0058] S5: Perform intermediate annealing on the aluminum foil blank of the current collector battery.

[0059] In some alternative embodiments, the intermediate annealing temperature can be 490℃~510℃ (e.g., 490℃, 495℃, 500℃, 505℃ or 510℃, etc.), and the holding time can be 140min~160min (e.g., 140min, 150min or 160min, etc.).

[0060] In some optional embodiments, the hot-rolled current collector aluminum foil blank is placed in a box-type resistance furnace and heated to 490°C to 510°C at a heating rate of 8°C / min to 10°C / min, and held at 490°C to 510°C for 140 min to 160 min.

[0061] S6: Cool the aluminum foil blank of the current collector battery after intermediate annealing (e.g., air cool to room temperature), and then perform multiple cold rolling passes to obtain the cold-rolled finished aluminum foil.

[0062] In some alternative implementations, the number of cold rolling passes in multi-pass cold rolling can be 4 to 9, such as 4, 5, 6, 7, 8 or 9.

[0063] In some alternative embodiments, the thickness of the cold-rolled finished aluminum foil obtained after multiple cold rolling passes is 0.28 mm to 0.33 mm.

[0064] In some alternative embodiments, a four-roll cold rolling mill is used to cold roll the intermediate annealed current collector aluminum foil blank. For example, it can be rolled in 4 passes, 8 passes, or 9 passes to obtain cold-rolled finished aluminum foil with diameters of 1.3mm~1.4mm, 0.4mm~0.45mm, or 0.28mm~0.35mm, respectively.

[0065] S7: Anneal the cold-rolled finished aluminum foil.

[0066] In some optional embodiments, the annealing temperature of the cold-rolled finished aluminum foil can be 190℃~210℃ (e.g., 190℃, 195℃, 200℃, 205℃ or 210℃, etc.), and the holding time can be 5h~7h (e.g., 5h, 6h or 7h, etc.).

[0067] In some optional embodiments, the cold-rolled finished aluminum foil is placed in a box-type resistance furnace for annealing, heated to 190°C to 210°C at a heating rate of 6°C / min to 8°C / min, held at 190°C to 210°C for 5 to 7 hours, and then air-cooled to room temperature.

[0068] Building upon the above, this invention, through the synergistic optimization of key process parameters such as homogenization, hot rolling, annealing, and cold rolling, not only ensures the strength advantage brought about by the increased alloying degree, but also eliminates work hardening and adjusts the microstructure through intermediate annealing and finished product annealing, avoiding the difficulties in rolling processing caused by excessive strength during the rolling process. This ensures that the resulting high-performance current collector battery aluminum foil has properties such as high tensile strength, high elongation, and high conductivity.

[0069] In addition, the present invention also provides a battery containing the aforementioned high-performance current collector aluminum foil.

[0070] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0071] Example 1 This embodiment provides a high-performance current collector battery aluminum foil, which, by mass percentage, contains 0.32% Fe, 0.30% Si, 0.02% Cu, 0.001% Ti, 0.002% Mn, 0.003% Mg, 0.001% V, 0.003% Zn, and 0.044% Ce, with the balance being Al and unavoidable impurities.

[0072] The method for preparing the high-performance current collector battery aluminum foil includes the following steps: S1: Weigh the corresponding raw materials according to the preset composition and ratio of the aluminum foil, and place the Al-Si master alloy, Al-Fe master alloy, and Al-Ce master alloy into a box-type resistance furnace for drying. Heat the melting furnace to 780℃, add high-purity aluminum ingots (99.99wt%) and wait for them to completely melt. When the temperature drops to 740℃, add the aforementioned master alloys to the aluminum melt. After 20 minutes until the master alloys are completely melted, stir to obtain an aluminum alloy melt. Use 99.99% pure argon gas and 0.2wt% aluminum molten salt composite refining agent to spray and refine the aluminum alloy melt at 730℃ in the melting furnace for 20 minutes. Then remove slag and let it stand for 20 minutes.

[0073] By mass percentage, the aluminum molten salt composite refining agent contains 25% Na, 5% K, 18% Cl, 9% Si, 14% F, 20% O, 10% Ca, and 5% S.

[0074] S2: The refined and deslag-removed aluminum alloy molten liquid is transferred to a degassing box for online degassing, using argon gas as the degassing medium at a flow rate of 0.5 m³ / h. 3 The degassing rate was 720℃, and the degassing time was 30 minutes. After degassing, the aluminum melt was obtained through plate filtration (50PPi+60PPi dual-stage ceramic foam filter plate) and tubular filtration (RB-grade tubular filtration). The aluminum melt was then cast to obtain an aluminum alloy ingot with a thickness of 30mm.

[0075] S3: The aluminum alloy ingot is placed in a heating furnace for homogenization treatment. The homogenization process is 580℃×8h, with a heating rate of 9℃ / min. After holding at this temperature, it is cooled to room temperature with the furnace. The surface (including the sides) of the homogenized ingot is milled using a modern CNC milling machine to remove the surface defect layer. After milling, the flatness of the ingot is ≤0.3mm / m, the surface roughness Ra<5μm, and the thickness is 29mm.

[0076] S4: The milled ingot is placed vertically into a box-type resistance furnace and heated to 500℃ for 120 minutes. After the holding time, the current collector aluminum foil blank is obtained by multiple hot rolling passes. The initial thickness of the ingot is 29mm. After 5 hot rolling passes, the holding time of each pass is 15 minutes. The thickness of the current collector aluminum foil blank after hot rolling is 2.82mm. The two-roll mill used for hot rolling is LG500, with a maximum rolling force of 180 tons, a work roll diameter of 420mm, a roll surface width of 500mm, a rolling speed of 0.36m / s, and a reduction speed of 0.417mm / s. 5% soap-based emulsion (a mixture of oleic acid and triethanolamine in a volume ratio of 1:1) is added during the hot rolling process.

[0077] S5: The hot-rolled current collector battery aluminum foil blank is placed in a box-type resistance furnace for intermediate annealing, specifically heated to 500℃ at a heating rate of 9℃ / min and held for 150min.

[0078] S6: The aluminum foil blank for current collector batteries, after intermediate annealing, is air-cooled to room temperature, and then cold-rolled multiple times using a four-roll cold rolling mill to obtain the cold-rolled finished aluminum foil. The specifications of the cold rolling mill are 110 / 320×300 (work roll diameter is 110mm, support roll diameter is 320mm, roll body length is 300mm), the roll speed is 1m / s, the rolling pressure is 80 tons, and there are a total of 9 cold rolling passes, resulting in a cold-rolled finished aluminum foil thickness of 0.32mm. The cold rolling process is as follows: 2.82mm → four passes to 1.34mm → eight passes to 0.45mm → nine passes to 0.32mm.

[0079] S7: Place the cold-rolled finished aluminum foil into a box-type resistance furnace for annealing. Specifically, heat the foil to 200°C at a heating rate of 7°C / min and hold it at that temperature for 6 hours, then air-cool it to room temperature.

[0080] Example 2 This embodiment provides a high-performance current collector battery aluminum foil, which, by mass percentage, contains 0.45% Fe, 0.30% Si, 0.04% Cu, 0.002% Ti, 0.002% Mn, 0.006% Mg, 0.001% V, 0.003% Zn, and 0.11% Ce, with the balance being Al and unavoidable impurities.

[0081] The method for preparing the high-performance current collector battery aluminum foil includes the following steps: S1: Weigh the corresponding raw materials according to the preset composition and ratio of the aluminum foil, and place the Al-Si master alloy, Al-Fe master alloy, and Al-Ce master alloy into a box-type resistance furnace for drying. Heat the melting furnace to 780℃, add high-purity aluminum ingots (99.99wt%) and wait for them to completely melt. When the temperature drops to 730℃, add the aforementioned master alloys to the molten aluminum. After 20 minutes until the master alloys are completely melted, stir to obtain molten aluminum alloy. Use 99.99% pure argon gas and 0.25wt% aluminum molten salt composite refining agent to spray and refine the molten aluminum alloy at 730℃ in the melting furnace for 25 minutes. Then remove slag and let it stand for 20 minutes.

[0082] By mass percentage, the aluminum molten salt composite refining agent contains 20% Na, 3% K, 13% Cl, 6% Si, 10% F, 15% O, 5% Ca, and 3% S.

[0083] S2: The refined and deslag-removed aluminum alloy molten liquid is transferred to a degassing box for online degassing, using argon gas as the degassing medium at a flow rate of 0.4 m³ / h. 3The degassing rate was 720℃, and the degassing time was 25 minutes. After degassing, the aluminum melt was obtained through plate filtration (50PPi+60PPi dual-stage ceramic foam filter plate) and tubular filtration (RB-grade tubular filtration). The aluminum melt was then cast to obtain an aluminum alloy ingot with a thickness of 30mm.

[0084] S3: The aluminum alloy ingot is placed in a heating furnace for homogenization treatment. The homogenization process is 580℃×8h, with a heating rate of 8℃ / min. After holding at this temperature, it is cooled to room temperature with the furnace. The surface (including the sides) of the homogenized ingot is milled using a modern CNC milling machine to remove the surface defect layer. After milling, the flatness of the ingot is ≤0.3mm / m, the surface roughness Ra<5μm, and the thickness is 29mm.

[0085] S4: The milled ingot is placed vertically into a box-type resistance furnace and heated to 500℃ for 120 minutes. After the holding time, the current collector aluminum foil blank is obtained by multiple hot rolling passes. The initial thickness of the ingot is 29mm. After 5 hot rolling passes, the holding time of each pass is 10 minutes. The thickness of the current collector aluminum foil blank after hot rolling is 2.77mm. The two-roll mill used for hot rolling is LG500, with a maximum rolling force of 180 tons, a work roll diameter of 420mm, a roll surface width of 500mm, a rolling speed of 0.36m / s, and a reduction speed of 0.417mm / s. 6% soap-based emulsion (a mixture of oleic acid and triethanolamine in a volume ratio of 1:1) is added during the hot rolling process.

[0086] S5: The hot-rolled current collector battery aluminum foil blank is placed in a box-type resistance furnace for intermediate annealing, specifically heated to 500℃ at a heating rate of 8℃ / min and held for 150min.

[0087] S6: The aluminum foil blank for current collectors, after intermediate annealing, is air-cooled to room temperature, and then cold-rolled multiple times using a four-roll cold rolling mill to obtain the finished cold-rolled aluminum foil. The specifications of the cold rolling mill are 110 / 320×300 (work roll diameter is 110mm, support roll diameter is 320mm, roll body length is 300mm), the roll speed is 1m / s, the rolling pressure is 80 tons, and there are a total of 9 cold rolling passes, resulting in a finished cold-rolled aluminum foil with a thickness of 0.35mm. The cold rolling process is as follows: 2.77mm → four passes to 1.37mm → eight passes to 0.44mm → nine passes to 0.35mm.

[0088] S7: Place the cold-rolled finished aluminum foil into a box-type resistance furnace for annealing. Specifically, heat the foil to 200°C at a heating rate of 6°C / min and hold it at that temperature for 6 hours, then air-cool it to room temperature.

[0089] Example 3 This embodiment provides a high-performance current collector aluminum foil, which, by mass percentage, contains 0.41% Fe, 0.31% Si, 0.01% Cu, 0.002% Ti, 0.002% Mn, 0.006% Mg, 0.001% V, 0.006% Zn, and 0.16% Ce, with the balance being Al and unavoidable impurities.

[0090] The method for preparing the high-performance current collector battery aluminum foil includes the following steps: S1: Weigh the corresponding raw materials according to the preset composition and ratio of the aluminum foil, and place the Al-Si master alloy, Al-Fe master alloy, and Al-Ce master alloy into a box-type resistance furnace for drying. Heat the melting furnace to 780℃, add high-purity aluminum ingots (99.99wt%) and wait for them to completely melt. When the temperature drops to 750℃, add the aforementioned master alloys to the molten aluminum. After 15 minutes until the master alloys are completely melted, stir to obtain molten aluminum alloy. Use 99.99% pure argon gas and 0.3wt% aluminum molten salt composite refining agent to spray and refine the molten aluminum alloy at 750℃ in the melting furnace for 20 minutes. Then remove slag and let it stand for 20 minutes.

[0091] By mass percentage, the aluminum molten salt composite refining agent contains 30% Na, 5% K, 23% Cl, 12% Si, 18% F, 25% O, 15% Ca, and 5% S.

[0092] S2: The refined and deslag-removed aluminum alloy molten liquid is transferred to a degassing box for online degassing, using argon gas as the degassing medium at a flow rate of 0.3 m³ / h. 3 The degassing rate was 720℃, and the degassing time was 20min. After degassing, the aluminum melt was obtained through plate filtration (50PPi+60PPi dual-stage ceramic foam filter plate) and tubular filtration (RB-grade tubular filtration). The aluminum melt was then cast to obtain an aluminum alloy ingot with a thickness of 30mm.

[0093] S3: The aluminum alloy ingot is placed in a heating furnace for homogenization treatment. The homogenization process is 580℃×8h, with a heating rate of 10℃ / min. After holding at this temperature, it is cooled to room temperature in the furnace. The surface (including the sides) of the homogenized ingot is milled using a modern CNC milling machine to remove the surface defect layer. After milling, the flatness of the ingot is ≤0.3mm / m, the surface roughness Ra<5μm, and the thickness is 29mm.

[0094] S4: The milled ingot is placed vertically into a box-type resistance furnace and heated to 500℃ for 120 minutes. After the holding time, the current collector aluminum foil blank is obtained by multiple hot rolling passes. The initial thickness of the ingot is 29mm. After 5 hot rolling passes, the holding time of each pass is 20 minutes. The thickness of the current collector aluminum foil blank after hot rolling is 2.74mm. The two-roll mill used for hot rolling is LG500, with a maximum rolling force of 180 tons, a work roll diameter of 420mm, a roll surface width of 500mm, a rolling speed of 0.36m / s, and a reduction speed of 0.417mm / s. 7% soap-based emulsion (a mixture of oleic acid and triethanolamine in a volume ratio of 1:1) is added during the hot rolling process.

[0095] S5: The hot-rolled current collector battery aluminum foil blank is placed in a box-type resistance furnace for intermediate annealing, specifically heated to 500℃ at a heating rate of 10℃ / min and held for 150min.

[0096] S6: The aluminum foil blank for current collector batteries, after intermediate annealing, is air-cooled to room temperature, and then cold-rolled multiple times using a four-roll cold rolling mill to obtain the cold-rolled finished aluminum foil. The specifications of the cold rolling mill are 110 / 320×300 (work roll diameter is 110mm, support roll diameter is 320mm, roll body length is 300mm), the roll speed is 1m / s, the rolling pressure is 80 tons, and there are a total of 9 cold rolling passes, resulting in a cold-rolled finished aluminum foil thickness of 0.33mm. The cold rolling process is as follows: 2.74mm → four passes to 1.36mm → eight passes to 0.42mm → nine passes to 0.33mm.

[0097] S7: Place the cold-rolled finished aluminum foil into a box-type resistance furnace for annealing. Specifically, heat the foil to 200°C at a heating rate of 8°C / min and hold it at that temperature for 6 hours, then air-cool it to room temperature.

[0098] Example 4 This embodiment provides a high-performance current collector battery aluminum foil, which, by mass percentage, contains 0.38% Fe, 0.32% Si, 0.02% Cu, 0.003% Ti, 0.002% Mn, 0.003% Mg, 0.001% V, 0.003% Zn, and 0.23% Ce, with the balance being Al and unavoidable impurities.

[0099] The method for preparing the high-performance current collector battery aluminum foil includes the following steps: S1: Weigh the corresponding raw materials according to the preset composition and ratio of the aluminum foil, and place the Al-Si master alloy, Al-Fe master alloy, and Al-Ce master alloy into a box-type resistance furnace for drying. Heat the melting furnace to 780℃, add high-purity aluminum ingots (99.99wt%) and wait for them to completely melt. When the temperature drops to 730℃, add the aforementioned master alloys to the molten aluminum. After 20 minutes until the master alloys are completely melted, stir to obtain molten aluminum alloy. Use 99.99% pure argon gas and 0.3wt% aluminum molten salt composite refining agent to spray and refine the molten aluminum alloy at 730℃ in the melting furnace for 20 minutes. Then remove slag and let it stand for 20 minutes.

[0100] By mass percentage, the aluminum molten salt composite refining agent contains 25% Na, 5% K, 18% Cl, 9% Si, 14% F, 20% O, 10% Ca, and 5% S.

[0101] S2: The refined and deslag-removed aluminum alloy molten liquid is transferred to a degassing box for online degassing, using argon gas as the degassing medium at a flow rate of 0.2 m³ / h. 3 The degassing rate was 1 / min, the degassing chamber temperature was 720℃, and the degassing time was 15min. After degassing, the aluminum melt was obtained by plate filtration (50PPi+60PPi dual-stage ceramic foam filter plate) and tubular filtration (RB-grade tubular filtration). The aluminum melt was then cast to obtain an aluminum alloy ingot with a thickness of 30mm.

[0102] S3: The aluminum alloy ingot is placed in a heating furnace for homogenization treatment. The homogenization process is 580℃×8h, with a heating rate of 10℃ / min. After holding at this temperature, it is cooled to room temperature in the furnace. The surface (including the sides) of the homogenized ingot is milled using a modern CNC milling machine to remove the surface defect layer. After milling, the flatness of the ingot is ≤0.3mm / m, the surface roughness Ra<5μm, and the thickness is 29mm.

[0103] S4: The milled ingot is placed vertically in a box-type resistance furnace and heated to 500℃ for 120 minutes. After the holding time, the current collector aluminum foil blank is obtained by multiple hot rolling passes. The initial thickness of the ingot is 29mm. After 5 hot rolling passes, the holding time of each pass is 15 minutes. The thickness of the current collector aluminum foil blank after hot rolling is 2.82mm. The two-roll mill used for hot rolling is LG500, with a maximum rolling force of 180 tons, a work roll diameter of 420mm, a roll surface width of 500mm, a rolling speed of 0.36m / s, and a reduction speed of 0.417mm / s. 8% soap-based emulsion (a mixture of oleic acid and triethanolamine in a volume ratio of 1:1) is added during the hot rolling process.

[0104] S5: The hot-rolled current collector battery aluminum foil blank is placed in a box-type resistance furnace for intermediate annealing, specifically heated to 500℃ at a heating rate of 10℃ / min and held for 150min.

[0105] S6: The aluminum foil blank for current collectors, after intermediate annealing, is air-cooled to room temperature, and then cold-rolled multiple times using a four-roll cold rolling mill to obtain the cold-rolled finished aluminum foil. The specifications of the cold rolling mill are 110 / 320×300 (work roll diameter is 110mm, support roll diameter is 320mm, roll body length is 300mm), the roll speed is 1m / s, the rolling pressure is 80 tons, and there are a total of 9 cold rolling passes, resulting in a cold-rolled finished aluminum foil thickness of 0.32mm. The cold rolling process is as follows: 2.82mm → four passes to 1.32mm → eight passes to 0.41mm → nine passes to 0.32mm.

[0106] S7: Place the cold-rolled finished aluminum foil into a box-type resistance furnace for annealing. Specifically, heat the foil to 200°C at a heating rate of 7°C / min and hold it at that temperature for 6 hours, then air-cool it to room temperature.

[0107] Comparative Example 1 The difference between this comparative example and Example 1 is that the high-performance current collector battery aluminum foil is not doped with Ce.

[0108] Comparative Example 2 The difference between this comparative example and Example 1 is that the amount of Ce in the aluminum foil of the high-performance current collector battery is 0.30%.

[0109] Comparative Example 3 The difference between this comparative example and Example 1 is that Ce in the high-performance current collector battery aluminum foil is replaced with Y in equal amounts.

[0110] Comparative Example 4 The difference between this comparative example and Example 1 is that Ce in the high-performance current collector battery aluminum foil is replaced with an equal amount of La.

[0111] Comparative Example 5 The difference between this comparative example and Example 1 is that the homogenization process is 580℃×10h.

[0112] Comparative Example 6 The difference between this comparative example and Example 1 is that the hot rolling temperature is 520°C.

[0113] Test case The mechanical properties and conductivity of the cold-rolled current collector aluminum foil prepared in S6 and the annealed current collector aluminum foil prepared in S7 of Examples 1-4 and Comparative Examples 1-6 were tested and measured. The results are shown in Table 1 and Table 2.

[0114] Among them, tensile strength, yield strength and elongation at break are tested in accordance with GB / T 16865-2023, and electrical conductivity is tested in accordance with GB / T 12966-2022. The electrical conductivity is tested at 3 random locations.

[0115] Table 1 Mechanical properties of aluminum foil

[0116] Table 2 Conductivity of Aluminum Foil

[0117] As can be seen from Tables 1 and 2, the aluminum foils prepared in Examples 1-4 of this invention, whether in the cold-rolled or annealed state, all exhibit superior overall performance compared to the comparative examples.

[0118] In summary, this invention optimizes the alloy composition design and controls the addition ratio of the rare earth element Ce. Utilizing the purification and refining effect of Ce on the aluminum alloy melt, Ce combines with Fe and Si elements to form novel compounds, effectively improving the morphology and size of the trace coarse AlFeSi phases in the alloy. Simultaneously, it hinders dislocation movement and grain boundary migration, achieving grain refinement and strengthening. By synergistically optimizing key process parameters such as homogenization, hot rolling, annealing, and cold rolling, the strength advantage brought by the increased alloying degree is ensured, while intermediate and finished annealing eliminates work hardening and adjusts the microstructure, avoiding difficulties in rolling due to excessive strength. The solution provided by this invention solves the problem of poor synergy between strength, toughness, and conductivity in traditional 1060 series aluminum foil, obtaining a high-performance current collector battery aluminum foil with high tensile strength, elongation, and conductivity.

[0119] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-performance current collector battery aluminum foil, characterized in that, The high-performance current collector aluminum foil contains, by mass percentage, 0.30%~0.45% Fe, 0.30%~0.32% Si, 0.01%~0.04% Cu, ≤0.004% Ti, ≤0.004% Mn, ≤0.006% Mg, ≤0.004% V, ≤0.006% Zn, and 0.02%~0.25% Ce, with the balance being Al and unavoidable impurities.

2. The high-performance current collector battery aluminum foil according to claim 1, characterized in that, The high-performance current collector aluminum foil contains 0.32%~0.45% Fe, 0.30%~0.32% Si, 0.01%~0.04% Cu, 0.001%~0.003% Ti, 0.002% Mn, 0.003%~0.006% Mg, 0.001% V, 0.003%~0.006% Zn, and 0.044%~0.23% Ce, with the balance being Al and unavoidable impurities.

3. The high-performance current collector battery aluminum foil according to claim 1 or 2, characterized in that, The high-performance current collector battery aluminum foil also has at least one of the following characteristics: Feature 1: The high-performance current collector aluminum foil has a tensile strength ≥160MPa in the cold-rolled state; Feature 2: The high-performance current collector aluminum foil has a yield strength ≥145MPa in the cold-rolled state; Feature 3: The high-performance current collector aluminum foil has an elongation at break of ≥4% in the cold-rolled state; Feature 4: The high-performance current collector aluminum foil has a conductivity ≥44% IACS in the cold-rolled state; Feature 5: The tensile strength of the high-performance current collector aluminum foil in the annealed state is ≥143MPa; Feature 6: The high-performance current collector aluminum foil has a yield strength ≥128MPa in the annealed state; Feature 7: The high-performance current collector aluminum foil has an elongation at break of ≥2% in the annealed state; Feature 8: The high-performance current collector aluminum foil has a conductivity of ≥47% IACS in the annealed state.

4. A method for preparing high-performance current collector battery aluminum foil as described in any one of claims 1 to 3, characterized in that, Includes the following steps: Raw materials that meet the preset composition and ratio of aluminum foil are smelted to obtain aluminum alloy melt; The molten aluminum alloy is refined; The refined aluminum alloy melt is degassed and filtered online, and the filtered aluminum melt is cast to obtain aluminum alloy ingots. The aluminum alloy ingot is homogenized and its surface is milled to obtain a homogenized ingot; The homogenized ingot is subjected to multiple hot rolling passes to obtain a current collector battery aluminum foil sheet blank. The current collector battery aluminum foil sheet blank is subjected to intermediate annealing; The aluminum foil blank for current collector batteries after intermediate annealing is cooled and then subjected to multiple cold rolling passes to obtain cold-rolled finished aluminum foil. The cold-rolled finished aluminum foil is annealed.

5. The preparation method according to claim 4, characterized in that, The amount of aluminum molten salt composite refining agent used in the refining process is 0.2wt%~0.3wt% of the aluminum alloy melt; Preferably, the aluminum molten salt composite refining agent contains, by mass percentage, 20%~30% Na, ≤5% K, 13%~23% Cl, 6%~12% Si, 10%~18% F, 15%~25% O, 5%~15% Ca and ≤5% S.

6. The preparation method according to claim 4, characterized in that, Online degassing was performed at 710℃~730℃ for 15min~30min, using argon as the degassing medium at a flow rate of 0.2m³ / min. 3 / min~0.5m 3 / min; And / or, the filtration adopts a three-stage filtration method using ceramic filters.

7. The preparation method according to claim 4, characterized in that, The homogenization treatment temperature is 570℃~590℃, and the holding time is 7h~8h; And / or, the intermediate annealing temperature is 490℃~510℃, and the holding time is 140min~160min; And / or, the annealing temperature of the cold-rolled finished aluminum foil is 190℃~210℃, and the holding time is 5h~7h.

8. The preparation method according to claim 4, characterized in that, The temperature of multi-pass hot rolling is 490℃~510℃, and the holding time for each pass is 10min~20min; Preferably, the number of hot rolling passes in multi-pass hot rolling is 4 to 6; Preferably, a soap-based emulsion is added during the multi-pass hot rolling process; Preferably, the soap-based emulsion comprises fatty acids and organic amines.

9. The preparation method according to claim 4, characterized in that, After cold rolling, the annealing temperature of the finished cold-rolled aluminum foil is 190℃~210℃, and the holding time is 5h~7h. Preferably, the number of cold rolling passes in multi-pass cold rolling is 4 to 9.

10. A battery, characterized in that, The battery contains the high-performance current collector aluminum foil as described in any one of claims 1 to 4.

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