A high-conductivity and high-uniformity 1060 aluminum foil for lithium iron phosphate battery positive electrode current collector
By optimizing the aluminum foil metal formulation and process flow, the problem of insufficient conductivity and uniformity of traditional aluminum foil at thin thicknesses has been solved, thus improving the overall performance and quality of lithium iron phosphate batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGXI GUOCHAO ALUMINUM CO LTD
- Filing Date
- 2026-02-10
- Publication Date
- 2026-05-08
AI Technical Summary
Traditional battery aluminum foil struggles to maintain sufficient conductivity, performance, plate shape, and uniformity while keeping it extremely thin, thus affecting the overall quality of lithium iron phosphate power batteries.
By using aluminum foil metal materials with specific compositions, and through smelting, casting and rolling and cold continuous rolling processes, combined with air cushion continuous heat treatment, the foil rolling process is optimized to ensure the conductivity and uniformity of the aluminum foil.
It achieves high conductivity and uniformity, reduces processing scrap rate, and improves the performance and quality of lithium iron phosphate batteries.
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Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery aluminum foil processing technology, specifically relating to a high conductivity and high uniformity 1060 aluminum foil for use as a positive electrode current collector in lithium iron phosphate batteries. Background Technology
[0002] With the rapid development of the pure electric vehicle industry, the market demand for aluminum foil for lithium iron phosphate batteries has increased dramatically. This type of aluminum foil is mainly made of 1060 aluminum alloy. In recent years, in order to improve the energy density of lithium-ion batteries, the industry has generally adopted a higher compaction density process, which has put forward the performance requirements of thinner and stronger aluminum foil.
[0003] Currently, traditional battery aluminum foil struggles to maintain sufficient conductivity, performance, plate shape, thickness, and uniformity of structure while keeping it extremely thin. This shortcoming has affected the overall quality level of lithium iron phosphate power batteries. Summary of the Invention
[0004] To address the aforementioned problems, the present invention aims to provide a 1060 aluminum foil with high conductivity and high uniformity for use as a positive electrode current collector in lithium iron phosphate batteries.
[0005] The present invention achieves the above objectives through the following technical solutions:
[0006] This invention provides a high conductivity and high uniformity 1060 aluminum foil for use as a positive electrode current collector in lithium iron phosphate batteries. The high conductivity and high uniformity 1060 aluminum foil is obtained by melting and casting aluminum foil metal raw materials into a billet, and then cold continuous rolling and foil rolling of the billet.
[0007] By weight percentage, the aluminum foil metal composition comprises: 99.6-99.75% aluminum, 0.05-0.1% Al-Fe alloy, 0.05-0.08% Al-Si alloy, 0.01-0.05% Al-Cu alloy, 0.01% Al-Mn alloy, 0.01% magnesium, 0.02% zinc, and 0.01-0.02% Al-Ti alloy, with the remainder being unavoidable impurities.
[0008] Of these, by mass percentage, the Al-Fe alloy contains 20% iron and the remainder is aluminum; the Al-Si alloy contains 50% silicon and the remainder is aluminum; the Al-Cu alloy contains 50% copper and the remainder is aluminum; the Al-Mn alloy contains 10% manganese and the remainder is aluminum; and the Al-Ti alloy contains 5% titanium and the remainder is aluminum.
[0009] As a further optimization of the present invention, the specific process of smelting and casting aluminum foil metal materials into billets is as follows:
[0010] Heat the melting furnace to 680-700℃, first add aluminum to the melting furnace, and after the aluminum is completely melted, add Al-Fe alloy, Al-Si alloy and Al-Mn alloy, and stir the melt at 50-80 r / min for 20-30 min; cool the melting furnace to 670-690℃, add Al-Cu alloy and zinc, and stir the melt at 50-80 r / min for 10 min; cool the melting furnace to 660-670℃, add magnesium and refining agent, and stir the melt at 160 r / min for 5 min; add Al-Ti alloy, and stir the melt at 50-80 r / min for 10 min to obtain the melt;
[0011] Argon gas is introduced into the melt obtained from smelting at a flow rate of 0.5-1 L / min, with the gas flow reaching the bottom of the smelting furnace. The gas flow time is 10-15 min. After standing for 15-20 min, the slag is removed, and the melt is cast and rolled to obtain a billet with a thickness of 7.5-8.5 mm.
[0012] As a further optimization of the present invention, the refining agent is sodium hexafluoroaluminate, and the amount of the refining agent added is 0.1-0.2% of the melt.
[0013] As a further optimization of the present invention, the cold rolling process is as follows: the billet is subjected to cold rolling, and the cold rolling passes are allocated as follows: the first pass rolls from 7.5-8.5mm to 4.5-6.5mm, the second pass rolls from 4.5-6.5mm to 3.6-4.2mm, the third pass rolls from 3.6-4.2mm to 2.3-3.1mm, and the fourth pass rolls from 2.3-3.1mm to 1.3-1.8mm to obtain a cold-rolled billet.
[0014] As a further optimization of the present invention, the foil rolling process is as follows: the first pass rolls the foil from 1.3-1.8 mm to 0.7-0.9 mm, and the 0.7-0.9 mm cold-rolled billet undergoes air-cushion continuous heat treatment; the second pass rolls the foil from 0.7-0.9 mm to 0.4-0.6 mm; the third pass rolls the foil from 0.4-0.6 mm to 0.28-0.35 mm; the fourth pass rolls the foil from 0.28-0.35 mm to 0.12-0.18 mm; and the fifth pass rolls the foil from 0.12-0.18 mm... The first pass rolls the billet to 0.07-0.09 mm; the sixth pass rolls it from 0.07-0.09 mm to 0.03-0.05 mm; the seventh pass rolls it from 0.03-0.05 mm to 0.018-0.025 mm, and the 0.018-0.025 mm cold-rolled billet is then subjected to low-temperature annealing; the eighth pass rolls it from 0.018-0.025 mm to 0.008-0.012 mm, and the 0.008-0.012 mm cold-rolled billet is then subjected to low-temperature annealing to obtain 1060 aluminum foil with high conductivity and high uniformity.
[0015] As a further optimization of the present invention, the specific process of the air cushion continuous heat treatment is as follows:
[0016] The cold-rolled billet is fed into an air-cushion continuous heat treatment furnace, and nitrogen gas with a flow rate of 5-10 m³ / h is introduced into the furnace to heat the cold-rolled billet from room temperature to 250-280℃ and hold it for 2-3 minutes.
[0017] Keep nitrogen continuously flowing into the furnace, and at the same time open the protective gas inlet valve to allow the protective gas to enter the furnace at a flow rate of 3-5 m³ / h, heat the cold-rolled billet to 380-410℃, and hold for 10-30 minutes.
[0018] The cold-rolled billet is cooled in two stages: the first stage cools it to 200-220℃ at a cooling rate of 20-50℃ / min, and the second stage cools it to 20-30℃ at a cooling rate of 5-15℃ / min.
[0019] As a further optimization of the present invention, the protective gas is 95-98% nitrogen and 2-5% hydrogen.
[0020] As a further optimization of the present invention, the specific steps of low-temperature annealing of 0.018-0.025mm cold-rolled billet are as follows: under nitrogen protection, the cold-rolled billet is heated from room temperature to 280-320℃, held for 5-6 minutes, and cooled to 20-30℃ at a cooling rate of 5-15℃ / min.
[0021] As a further optimization of the present invention, the specific steps of low-temperature annealing of 0.008-0.012mm cold-rolled billet are as follows: under nitrogen protection, the cold-rolled billet is heated from room temperature to 250-280℃ and held for 5-6 minutes, and then cooled to 20-30℃ at a cooling rate of 5-15℃ / min.
[0022] The beneficial effects of this invention are as follows: This invention adopts a cold continuous rolling uniform rolling method, and adds air cushion continuous heat treatment during the foil rolling process, which can not only eliminate rolling stress in time and prevent the aluminum foil from cracking during large deformation processing; in addition, the air cushion continuous heat treatment in the cold continuous rolling process can fully ensure the uniformity of aluminum foil composition, uniformity of structure and uniformity of thickness, and effectively reduce the scrap rate of subsequent processing. Detailed Implementation
[0023] The present application will now be described in further detail. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.
[0024] Unless otherwise specified, all methods used in this invention are conventional methods known to those skilled in the art, and all reagents and materials used are commercially available products.
[0025] In this invention, by mass percentage, the Al-Fe alloy has an iron content of 20% and the remainder is aluminum; the Al-Si alloy has a silicon content of 50% and the remainder is aluminum; the Al-Cu alloy has a copper content of 50% and the remainder is aluminum; the Al-Mn alloy has a manganese content of 10% and the remainder is aluminum; and the Al-Ti alloy has a titanium content of 5% and the remainder is aluminum.
[0026] Example 1
[0027] The specific process of aluminum foil metal raw materials being smelted, cast, and rolled into billets is as follows:
[0028] The melting furnace was heated to 680℃. Aluminum was first added to the furnace and, after complete melting, Al-Fe alloy, Al-Si alloy, and Al-Mn alloy were added. The melt was stirred at 50 r / min for 20 min. The melting furnace was then cooled to 670℃, and Al-Cu alloy and zinc were added. The melt was stirred at 50 r / min for 10 min. The melting furnace was then cooled to 660℃, and magnesium and sodium hexafluoroaluminate were added. The melt was stirred at 160 r / min for 5 min. Finally, Al-Ti alloy was added, and the melt was stirred at 50 r / min for 10 min to obtain the final melt.
[0029] By weight percentage, the aluminum foil metal composition comprises: 99.65% aluminum, 0.08% Al-Fe alloy, 0.08% Al-Si alloy, 0.02% Al-Cu alloy, 0.01% Al-Mn alloy, 0.01% magnesium, 0.02% zinc, and 0.01% Al-Ti alloy, with the remainder being unavoidable impurities; sodium hexafluoroaluminate is added at 0.1% of the melt.
[0030] Argon gas is introduced into the melt obtained by smelting at a flow rate of 0.5 L / min, the gas depth is to the bottom of the smelting furnace, the gas introduction time is 10 min, and after standing for 15 min, the slag is removed. The melt is then cast and rolled to obtain a billet with a thickness of 8.5 mm.
[0031] Cold rolling: The billet is subjected to cold rolling. The cold rolling passes are allocated as follows: the first pass rolls from 8.5mm to 6.5mm, the second pass rolls from 6.5mm to 4.2mm, the third pass rolls from 4.2mm to 3.1mm, and the fourth pass rolls from 3.1mm to 1.8mm to obtain a cold-rolled billet.
[0032] Foil rolling: The cold-rolled billet is cleaned in a cleaning machine, then immersed in a 5% sodium hydroxide aqueous solution at 50℃ for 5 minutes, rinsed with water, and then immersed in a 3% nitric acid aqueous solution at 25℃ for 3 minutes. After rinsing with water and drying with hot air at 80℃, it undergoes continuous cold rolling. The pass allocation is as follows: the first pass rolls from 1.8mm to 0.9mm, and the 0.9mm cold-rolled billet undergoes air-cushion continuous heat treatment; the second pass rolls from 0.9mm to 0.6mm; the third pass rolls from 0.6mm to 0.35mm; the fourth pass rolls from 0.35mm to 0.18mm; the fifth pass rolls from 0.1mm to 0.1mm. The 8mm cold-rolled billet is rolled to 0.09mm; in the sixth pass, it is rolled from 0.09mm to 0.05mm; in the seventh pass, it is rolled from 0.05mm to 0.025mm. Under nitrogen protection, the 0.025mm cold-rolled billet is heated from room temperature to 280℃ and held for 5 minutes, then cooled to 20℃ at a cooling rate of 5℃ / min; in the eighth pass, it is rolled from 0.025mm to 0.011mm. Under nitrogen protection, the 0.011mm cold-rolled billet is heated from room temperature to 250℃ and held for 5 minutes, then cooled to 20℃ at a cooling rate of 5℃ / min, to obtain a 1060 aluminum foil with high conductivity and high uniformity.
[0033] The specific process of air cushion continuous heat treatment is as follows:
[0034] The cold-rolled billet is fed into an air-cushion continuous heat treatment furnace, and nitrogen gas with a flow rate of 5 m³ / h is introduced into the furnace to heat the cold-rolled billet from room temperature to 250°C and hold it for 2 min.
[0035] Keep nitrogen continuously flowing into the furnace, and at the same time open the protective gas inlet valve (the protective gas is 95% nitrogen and 5% hydrogen) to allow the protective gas to enter the furnace at a flow rate of 3 m³ / h, heat the cold-rolled billet to 380°C, and hold for 10 min.
[0036] The cold-rolled billet is cooled in two stages: the first stage cools it to 200°C at a cooling rate of 20°C / min, and the second stage cools it to 20°C at a cooling rate of 5°C / min.
[0037] Example 2
[0038] The specific process of aluminum foil metal raw materials being smelted, cast, and rolled into billets is as follows:
[0039] The melting furnace was heated to 690℃. Aluminum was first added to the furnace and, after complete melting, Al-Fe alloy, Al-Si alloy, and Al-Mn alloy were added. The melt was stirred at 65 r / min for 25 min. The melting furnace was then cooled to 680℃, and Al-Cu alloy and zinc were added. The melt was stirred at 75 r / min for 10 min. The melting furnace was then cooled to 665℃, and magnesium and sodium hexafluoroaluminate were added. The melt was stirred at 160 r / min for 5 min. Finally, Al-Ti alloy was added, and the melt was stirred at 60 r / min for 10 min to obtain the final melt.
[0040] By weight percentage, the aluminum foil metal composition comprises: 99.70% aluminum, 0.1% Al-Fe alloy, 0.08% Al-Si alloy, 0.04% Al-Cu alloy, 0.01% Al-Mn alloy, 0.01% magnesium, 0.02% zinc, and 0.01% Al-Ti alloy, with the remainder being unavoidable impurities; sodium hexafluoroaluminate is added at 0.15% of the melt.
[0041] Argon gas is introduced into the melt obtained by smelting at a flow rate of 0.8 L / min, the gas depth is to the bottom of the smelting furnace, the gas introduction time is 12 min, and after standing for 18 min, the slag is removed. The melt is then cast and rolled to obtain a billet with a thickness of 8 mm.
[0042] Cold rolling: The billet is subjected to cold rolling. The cold rolling passes are allocated as follows: the first pass rolls from 8mm to 5.5mm, the second pass rolls from 5.5mm to 3.8mm, the third pass rolls from 3.8mm to 2.5mm, and the fourth pass rolls from 2.5mm to 1.5mm to obtain a cold-rolled billet.
[0043] Foil rolling: The cold-rolled billet is cleaned in a cleaning machine, then immersed in a 6% sodium hydroxide aqueous solution at 55℃ for 5 minutes, rinsed with water, and then immersed in a 4% nitric acid aqueous solution at 27℃ for 3 minutes. After rinsing with water and drying with hot air at 85℃, it undergoes continuous cold rolling. The pass allocation is as follows: the first pass rolls from 1.5mm to 0.8mm, and the 0.8mm cold-rolled billet undergoes air-cushion continuous heat treatment; the second pass rolls from 0.8mm to 0.5mm; the third pass rolls from 0.5mm to 0.3mm; the fourth pass rolls from 0.3mm to 0.15mm; the fifth pass rolls from 0... The 0.02mm cold-rolled billet was rolled from 0.15mm to 0.08mm in the sixth pass, from 0.08mm to 0.04mm in the seventh pass, and from 0.04mm to 0.02mm in the eighth pass. Under nitrogen protection, the 0.02mm cold-rolled billet was heated from room temperature to 300℃ and held for 5 minutes, then cooled to 25℃ at a cooling rate of 10℃ / min. The 0.02mm cold-rolled billet was rolled from 0.01mm to 0.01mm in the eighth pass. Under nitrogen protection, the 0.01mm cold-rolled billet was heated from room temperature to 260℃ and held for 5 minutes, then cooled to 25℃ at a cooling rate of 12℃ / min to obtain a highly conductive and highly uniform 1060 aluminum foil.
[0044] The specific process of air cushion continuous heat treatment is as follows:
[0045] The cold-rolled billet is fed into an air-cushion continuous heat treatment furnace, and nitrogen gas with a flow rate of 8 m³ / h is introduced into the furnace to heat the cold-rolled billet from room temperature to 265°C and hold it for 2 min.
[0046] Keep nitrogen continuously flowing into the furnace, and at the same time open the protective gas inlet valve (the protective gas is 97% nitrogen and 3% hydrogen) to allow the protective gas to enter the furnace at a flow rate of 4 m³ / h, heat the cold-rolled billet to 390°C, and hold for 20 minutes.
[0047] The cold-rolled billet is cooled in two stages: the first stage cools it to 210°C at a cooling rate of 35°C / min, and the second stage cools it to 25°C at a cooling rate of 10°C / min.
[0048] Example 3
[0049] The specific process of aluminum foil metal raw materials being smelted, cast, and rolled into billets is as follows:
[0050] The melting furnace was heated to 700℃. Aluminum was first added to the furnace and, after complete melting, Al-Fe alloy, Al-Si alloy, and Al-Mn alloy were added. The melt was stirred at 80 r / min for 30 min. The melting furnace was then cooled to 690℃, and Al-Cu alloy and zinc were added. The melt was stirred at 80 r / min for 10 min. The melting furnace was then cooled to 670℃, and magnesium and sodium hexafluoroaluminate were added. The melt was stirred at 160 r / min for 5 min. Finally, Al-Ti alloy was added, and the melt was stirred at 80 r / min for 10 min to obtain the final melt.
[0051] By weight percentage, the aluminum foil metal composition comprises: 99.75% aluminum, 0.07% Al-Fe alloy, 0.06% Al-Si alloy, 0.05% Al-Cu alloy, 0.01% Al-Mn alloy, 0.01% magnesium, 0.02% zinc, and 0.02% Al-Ti alloy, with the remainder being unavoidable impurities; sodium hexafluoroaluminate is added at 0.2% of the melt.
[0052] Argon gas is introduced into the melt obtained by smelting at a flow rate of 1L / min, the gas depth is to the bottom of the smelting furnace, the gas introduction time is 15min, and after standing for 20min, the slag is removed. The melt is then cast and rolled to obtain a billet with a thickness of 8.5mm.
[0053] Cold rolling: The billet is subjected to cold rolling. The cold rolling passes are allocated as follows: the first pass rolls from 8.5mm to 5.5mm, the second pass rolls from 5.5mm to 3.8mm, the third pass rolls from 3.8mm to 2.5mm, and the fourth pass rolls from 2.5mm to 1.5mm to obtain a cold-rolled billet.
[0054] Foil rolling: The cold-rolled billet is cleaned in a cleaning machine, then immersed in an 8% sodium hydroxide aqueous solution at 60℃ for 5 minutes, rinsed with water, and then immersed in a 5% nitric acid aqueous solution at 30℃ for 3 minutes. After rinsing with water and drying with hot air at 90℃, it undergoes continuous cold rolling. The pass allocation is as follows: the first pass rolls from 1.5mm to 0.8mm, and the 0.8mm cold-rolled billet undergoes air-cushion continuous heat treatment; the second pass rolls from 0.8mm to 0.5mm; the third pass rolls from 0.5mm to 0.3mm; the fourth pass rolls from 0.3mm to 0.15mm; the fifth pass rolls from 0... The 0.02mm cold-rolled billet was rolled from 0.15mm to 0.08mm in the sixth pass, from 0.08mm to 0.04mm in the seventh pass, and from 0.04mm to 0.02mm in the eighth pass. Under nitrogen protection, the 0.02mm cold-rolled billet was heated from room temperature to 320℃ and held for 6 minutes, then cooled to 30℃ at a cooling rate of 15℃ / min. The 0.01mm cold-rolled billet was heated from room temperature to 280℃ and held for 6 minutes under nitrogen protection, then cooled to 30℃ at a cooling rate of 15℃ / min to obtain a highly conductive and highly uniform 1060 aluminum foil.
[0055] The specific process of air cushion continuous heat treatment is as follows:
[0056] The cold-rolled billet is fed into an air-cushion continuous heat treatment furnace, and nitrogen gas with a flow rate of 10 m³ / h is introduced into the furnace to heat the cold-rolled billet from room temperature to 280°C and hold it for 3 minutes.
[0057] Keep nitrogen continuously flowing into the furnace, and at the same time open the protective gas inlet valve (the protective gas is 98% nitrogen and 2% hydrogen) to allow the protective gas to enter the furnace at a flow rate of 5 m³ / h, heat the cold-rolled billet to 410°C, and hold for 30 min.
[0058] The cold-rolled billet is cooled in two stages: the first stage cools it to 220°C at a cooling rate of 50°C / min, and the second stage cools it to 30°C at a cooling rate of 15°C / min.
[0059] Comparative Example 1
[0060] The specific process of aluminum foil metal raw materials being smelted, cast, and rolled into billets is as follows:
[0061] The melting furnace was heated to 690℃. Aluminum was first added to the furnace and, after complete melting, Al-Fe alloy, Al-Si alloy, and Al-Mn alloy were added. The melt was stirred at 65 r / min for 25 min. The melting furnace was then cooled to 680℃, and Al-Cu alloy and zinc were added. The melt was stirred at 75 r / min for 10 min. The melting furnace was then cooled to 665℃, and magnesium and sodium hexafluoroaluminate were added. The melt was stirred at 160 r / min for 5 min. Finally, Al-Ti alloy was added, and the melt was stirred at 60 r / min for 10 min to obtain the final melt.
[0062] By weight percentage, the aluminum foil metal composition comprises: 99.70% aluminum, 0.1% Al-Fe alloy, 0.08% Al-Si alloy, 0.04% Al-Cu alloy, 0.01% Al-Mn alloy, 0.01% magnesium, 0.02% zinc, and 0.01% Al-Ti alloy, with the remainder being unavoidable impurities; sodium hexafluoroaluminate is added at 0.15% of the melt.
[0063] Argon gas is introduced into the melt obtained by smelting at a flow rate of 0.8 L / min, the gas depth is to the bottom of the smelting furnace, the gas introduction time is 12 min, and after standing for 18 min, the slag is removed. The melt is then cast and rolled to obtain a billet with a thickness of 8 mm.
[0064] Cold rolling: The billet is subjected to cold rolling. The cold rolling passes are allocated as follows: the first pass rolls from 8mm to 5.5mm, the second pass rolls from 5.5mm to 3.8mm, the third pass rolls from 3.8mm to 2.5mm, and the fourth pass rolls from 2.5mm to 1.5mm to obtain a cold-rolled billet.
[0065] Foil rolling: The cold-rolled billet is cleaned in a cleaning machine, then immersed in a 6% sodium hydroxide aqueous solution at 55℃ for 5 minutes, rinsed with water, and then immersed in a 4% nitric acid aqueous solution at 27℃ for 3 minutes. After rinsing with water and drying with hot air at 85℃, it undergoes continuous cold rolling. The pass distribution is as follows: the first pass rolls from 1.5mm to 0.8mm; the second pass rolls from 0.8mm to 0.5mm; the third pass rolls from 0.5mm to 0.3mm; the fourth pass rolls from 0.3mm to 0.15mm; and the fifth pass rolls from 0.15mm to 0.0mm. The first pass rolled the 0.02mm cold-rolled billet from 0.08mm to 0.04mm; the second pass rolled the billet from 0.04mm to 0.02mm. Under nitrogen protection, the 0.02mm cold-rolled billet was heated from room temperature to 300℃ and held for 5 minutes, then cooled to 25℃ at a cooling rate of 10℃ / min; the third pass rolled the 0.02mm to 0.01mm cold-rolled billet from 0.01mm to 260℃ and held for 5 minutes under nitrogen protection, then cooled to 25℃ at a cooling rate of 12℃ / min, to obtain a highly conductive and highly uniform 1060 aluminum foil.
[0066] Comparative Example 2
[0067] The specific process of aluminum foil metal raw materials being smelted, cast, and rolled into billets is as follows:
[0068] The melting furnace was heated to 690℃. Aluminum was first added to the furnace and, after complete melting, Al-Fe alloy, Al-Si alloy, and Al-Mn alloy were added. The melt was stirred at 65 r / min for 25 min. The melting furnace was then cooled to 680℃, and Al-Cu alloy and zinc were added. The melt was stirred at 75 r / min for 10 min. The melting furnace was then cooled to 665℃, and magnesium and sodium hexafluoroaluminate were added. The melt was stirred at 160 r / min for 5 min. Finally, Al-Ti alloy was added, and the melt was stirred at 60 r / min for 10 min to obtain the final melt.
[0069] By weight percentage, the aluminum foil metal composition comprises: 99.70% aluminum, 0.1% Al-Fe alloy, 0.08% Al-Si alloy, 0.04% Al-Cu alloy, 0.01% Al-Mn alloy, 0.01% magnesium, 0.02% zinc, and 0.01% Al-Ti alloy, with the remainder being unavoidable impurities; sodium hexafluoroaluminate is added at 0.15% of the melt.
[0070] Argon gas is introduced into the melt obtained by smelting at a flow rate of 0.8 L / min, the gas depth is to the bottom of the smelting furnace, the gas introduction time is 12 min, and after standing for 18 min, the slag is removed. The melt is then cast and rolled to obtain a billet with a thickness of 8 mm.
[0071] Cold rolling: The billet is subjected to cold rolling. The cold rolling passes are allocated as follows: the first pass rolls from 8mm to 5.5mm, the second pass rolls from 5.5mm to 3.8mm, the third pass rolls from 3.8mm to 2.5mm, and the fourth pass rolls from 2.5mm to 1.5mm to obtain a cold-rolled billet.
[0072] Foil rolling: The cold-rolled billet is cleaned in a cleaning machine and then immersed in a 6% sodium hydroxide aqueous solution at 55°C for 5 minutes. After rinsing with water, it is immersed in a 4% nitric acid aqueous solution at 27°C for 3 minutes, rinsed with water, dried with hot air at 85°C, and then cold continuous rolling is performed. The pass allocation is as follows: the first pass rolls from 1.5mm to 0.8mm, and the 0.8mm cold-rolled billet undergoes air cushion continuous heat treatment; the second pass rolls from 0.8mm to 0.5mm; the third pass rolls from 0.5mm to 0.3mm. The fourth pass rolls the blank from 0.3mm to 0.15mm; the fifth pass rolls it from 0.15mm to 0.08mm; the sixth pass rolls it from 0.08mm to 0.04mm; the seventh pass rolls it from 0.04mm to 0.02mm; and the eighth pass rolls it from 0.02mm to 0.01mm. Under nitrogen protection, the 0.01mm cold-rolled blank is heated from room temperature to 260℃ and held for 5 minutes, then cooled to 25℃ at a cooling rate of 12℃ / min to obtain a 1060 aluminum foil with high conductivity and high uniformity.
[0073] The specific process of air cushion continuous heat treatment is as follows:
[0074] The cold-rolled billet is fed into an air-cushion continuous heat treatment furnace, and nitrogen gas with a flow rate of 8 m³ / h is introduced into the furnace to heat the cold-rolled billet from room temperature to 265°C and hold it for 2 min.
[0075] Keep nitrogen continuously flowing into the furnace, and at the same time open the protective gas inlet valve (the protective gas is 97% nitrogen and 3% hydrogen) to allow the protective gas to enter the furnace at a flow rate of 4 m³ / h, heat the cold-rolled billet to 390°C, and hold for 20 minutes.
[0076] The cold-rolled billet is cooled in two stages: the first stage cools it to 210°C at a cooling rate of 35°C / min, and the second stage cools it to 25°C at a cooling rate of 10°C / min.
[0077] Comparative Example 3
[0078] The specific process of aluminum foil metal raw materials being smelted, cast, and rolled into billets is as follows:
[0079] The melting furnace was heated to 690℃. Aluminum was first added to the furnace and, after complete melting, Al-Fe alloy, Al-Si alloy, and Al-Mn alloy were added. The melt was stirred at 65 r / min for 25 min. The melting furnace was then cooled to 680℃, and Al-Cu alloy and zinc were added. The melt was stirred at 75 r / min for 10 min. The melting furnace was then cooled to 665℃, and magnesium and sodium hexafluoroaluminate were added. The melt was stirred at 160 r / min for 5 min. Finally, Al-Ti alloy was added, and the melt was stirred at 60 r / min for 10 min to obtain the final melt.
[0080] By weight percentage, the aluminum foil metal composition comprises: 99.70% aluminum, 0.1% Al-Fe alloy, 0.08% Al-Si alloy, 0.04% Al-Cu alloy, 0.01% Al-Mn alloy, 0.01% magnesium, 0.02% zinc, and 0.01% Al-Ti alloy, with the remainder being unavoidable impurities; sodium hexafluoroaluminate is added at 0.15% of the melt.
[0081] Argon gas is introduced into the melt obtained by smelting at a flow rate of 0.8 L / min, the gas depth is to the bottom of the smelting furnace, the gas introduction time is 12 min, and after standing for 18 min, the slag is removed. The melt is then cast and rolled to obtain a billet with a thickness of 8 mm.
[0082] Cold rolling: The billet is subjected to cold rolling. The cold rolling passes are allocated as follows: the first pass rolls from 8mm to 5.5mm, the second pass rolls from 5.5mm to 3.8mm, the third pass rolls from 3.8mm to 2.5mm, and the fourth pass rolls from 2.5mm to 1.5mm to obtain a cold-rolled billet.
[0083] Foil rolling: The cold-rolled billet is cleaned in a cleaning machine, then immersed in a 6% sodium hydroxide aqueous solution at 55℃ for 5 minutes, rinsed with water, and then immersed in a 4% nitric acid aqueous solution at 27℃ for 3 minutes. After rinsing with water and drying with hot air at 85℃, it undergoes continuous cold rolling. The pass allocation is as follows: the first pass rolls from 1.5mm to 0.8mm, and the 0.8mm cold-rolled billet undergoes air-cushion continuous heat treatment; the second pass rolls from 0.8mm to 0.5mm; the third pass rolls from 0.5mm to 0.3mm. The fourth pass rolls the billet from 0.3mm to 0.15mm; the fifth pass rolls it from 0.15mm to 0.08mm; the sixth pass rolls it from 0.08mm to 0.04mm; the seventh pass rolls it from 0.04mm to 0.02mm. Under nitrogen protection, the 0.02mm cold-rolled billet is heated from room temperature to 300℃ and held for 5 minutes, then cooled to 25℃ at a cooling rate of 10℃ / min; the eighth pass rolls it from 0.02mm to 0.01mm, resulting in a highly conductive and highly uniform 1060 aluminum foil.
[0084] The specific process of air cushion continuous heat treatment is as follows:
[0085] The cold-rolled billet is fed into an air-cushion continuous heat treatment furnace, and nitrogen gas with a flow rate of 8 m³ / h is introduced into the furnace to heat the cold-rolled billet from room temperature to 265°C and hold it for 2 min.
[0086] Keep nitrogen continuously flowing into the furnace, and at the same time open the protective gas inlet valve (the protective gas is 97% nitrogen and 3% hydrogen) to allow the protective gas to enter the furnace at a flow rate of 4 m³ / h, heat the cold-rolled billet to 390°C, and hold for 20 minutes.
[0087] The cold-rolled billet is cooled in two stages: the first stage cools it to 210°C at a cooling rate of 35°C / min, and the second stage cools it to 25°C at a cooling rate of 10°C / min.
[0088] Performance testing
[0089] According to GB / T 228-2010 "Metallic materials - Tensile testing - Part 1: Test at room temperature", the highly conductive and highly uniform 1060 aluminum foils prepared by the methods of Examples 1-3 and Comparative Examples 1-3 were tested and analyzed.
[0090] According to GB / T 12966-2022 "Eddy Current Test Method for Conductivity of Aluminum and Aluminum Alloys", the highly conductive and highly uniform 1060 aluminum foils prepared by the methods of Examples 1-3 and Comparative Examples 1-3 were tested and analyzed; the analysis results are shown in the table below.
[0091]
[0092] As can be seen from the table above, the tensile strength of the examples reached 211-215 MPa and the yield strength reached 188-191 MPa, which is significantly improved compared with the tensile strength of 161-163 MPa and the yield strength of 142-143 MPa of the comparative examples; the elongation was 3.5%-3.8%, which is higher than the 2.1%-2.3% of the comparative examples, and the breakage rate was only 1.01%-1.03%, which is much lower than the 2.54%-3.12% of the comparative examples, indicating better uniformity; the electrical conductivity is positively correlated with the grain size. The grain size of the examples was 36-38 μm, and the conductivity reached 62.9-63.4 MS / m, while the grain size of the comparative examples was 71-74 μm, and the conductivity was only 52.1-52.8 MS / m.
[0093] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.
Claims
1. A high-conductivity, high-uniformity 1060 aluminum foil for use as a positive electrode current collector in lithium iron phosphate batteries, characterized in that... The high conductivity and high uniformity 1060 aluminum foil is obtained by melting and casting aluminum foil metal raw materials into a billet, and then cold continuous rolling and foil rolling of the billet. By weight percentage, the aluminum foil metal composition comprises: 99.6-99.75% aluminum, 0.05-0.1% Al-Fe alloy, 0.05-0.08% Al-Si alloy, 0.01-0.05% Al-Cu alloy, 0.01% Al-Mn alloy, 0.01% magnesium, 0.02% zinc, and 0.01-0.02% Al-Ti alloy, with the remainder being unavoidable impurities; Of these, by mass percentage, the Al-Fe alloy contains 20% iron and the remainder is aluminum; the Al-Si alloy contains 50% silicon and the remainder is aluminum; the Al-Cu alloy contains 50% copper and the remainder is aluminum; the Al-Mn alloy contains 10% manganese and the remainder is aluminum; and the Al-Ti alloy contains 5% titanium and the remainder is aluminum. The cold rolling process is as follows: the billet is subjected to cold rolling, and the cold rolling passes are allocated as follows: the first pass rolls from 7.5-8.5mm to 4.5-6.5mm, the second pass rolls from 4.5-6.5mm to 3.6-4.2mm, the third pass rolls from 3.6-4.2mm to 2.3-3.1mm, and the fourth pass rolls from 2.3-3.1mm to 1.3-1.8mm to obtain a cold-rolled billet; The foil rolling process is as follows: the cold-rolled billet is cleaned in a cleaning machine, then immersed in a 5-8% sodium hydroxide aqueous solution at 50-60℃ for 5 minutes, washed with water, then immersed in a 3-5% nitric acid aqueous solution at 25-30℃ for 3 minutes, washed with water and dried with hot air at 80-90℃, and then cold continuous rolling is performed. The pass allocation is as follows: the first pass rolls from 1.3-1.8mm to 0.7-0.9mm, and the 0.7-0.9mm cold-rolled billet undergoes air cushion continuous heat treatment; the second pass rolls from 0.7-0.9mm to 0.4-0.6mm; the third pass rolls from 0.4-0.6mm to 0.28-0.35mm; the fourth pass... The first pass rolls the billet from 0.28-0.35mm to 0.12-0.18mm; the fifth pass rolls it from 0.12-0.18mm to 0.07-0.09mm; the sixth pass rolls it from 0.07-0.09mm to 0.03-0.05mm; the seventh pass rolls it from 0.03-0.05mm to 0.018-0.025mm, and the 0.018-0.025mm cold-rolled billet is then subjected to low-temperature annealing; the eighth pass rolls it from 0.018-0.025mm to 0.008-0.012mm, and the 0.008-0.012mm cold-rolled billet is then subjected to low-temperature annealing to obtain a 1060 aluminum foil with high conductivity and high uniformity. The specific process of the air cushion continuous heat treatment is as follows: The cold-rolled billet is fed into an air-cushion continuous heat treatment furnace, and nitrogen gas with a flow rate of 5-10 m³ / h is introduced into the furnace to heat the cold-rolled billet from room temperature to 250-280℃ and hold it for 2-3 minutes. Keep nitrogen continuously flowing into the furnace, and at the same time open the protective gas inlet valve to allow the protective gas to enter the furnace at a flow rate of 3-5 m³ / h, heat the cold-rolled billet to 380-410℃, and hold for 10-30 minutes. The cold-rolled billet is cooled in two stages: the first stage cools it to 200-220℃ at a cooling rate of 20-50℃ / min, and the second stage cools it to 20-30℃ at a cooling rate of 5-15℃ / min. The specific steps for low-temperature annealing of the 0.018-0.025mm cold-rolled billet are as follows: under nitrogen protection, the cold-rolled billet is heated from room temperature to 280-320℃ and held for 5-6 minutes, and then cooled to 20-30℃ at a cooling rate of 5-15℃ / min. The specific steps for low-temperature annealing of the 0.008-0.012mm cold-rolled billet are as follows: under nitrogen protection, the cold-rolled billet is heated from room temperature to 250-280℃ and held for 5-6 minutes, and then cooled to 20-30℃ at a cooling rate of 5-15℃ / min.
2. The high conductivity and high uniformity 1060 aluminum foil for the positive electrode current collector of a lithium iron phosphate battery according to claim 1, characterized in that, The specific process of melting and casting the aluminum foil metal ingredients into billets is as follows: Heat the melting furnace to 680-700℃, first add aluminum to the melting furnace, and after the aluminum is completely melted, add Al-Fe alloy, Al-Si alloy and Al-Mn alloy, and stir the melt at 50-80 r / min for 20-30 min; cool the melting furnace to 670-690℃, add Al-Cu alloy and zinc, and stir the melt at 50-80 r / min for 10 min; cool the melting furnace to 660-670℃, add magnesium and refining agent, and stir the melt at 160 r / min for 5 min; add Al-Ti alloy, and stir the melt at 50-80 r / min for 10 min to obtain the melt; Argon gas is introduced into the melt obtained from smelting at a flow rate of 0.5-1 L / min, with the gas flow reaching the bottom of the smelting furnace. The gas flow time is 10-15 min. After standing for 15-20 min, the slag is removed, and the melt is cast and rolled to obtain a billet with a thickness of 7.5-8.5 mm.
3. The high conductivity and high uniformity 1060 aluminum foil for the positive electrode current collector of a lithium iron phosphate battery according to claim 2, characterized in that, The refining agent is sodium hexafluoroaluminate, and the amount of the refining agent added is 0.1-0.2% of the melt mass.
4. The high conductivity and high uniformity 1060 aluminum foil for the positive electrode current collector of a lithium iron phosphate battery according to claim 1, characterized in that, The protective gas is 95-98% nitrogen and 2-5% hydrogen.
Citation Information
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