Aluminum foil material for high-density energy storage equipment and preparation process of aluminum foil material

Abstract

The invention discloses an aluminum foil material for high-density energy storage equipment and a preparation method of the aluminum foil material. The aluminum foil material is made of high-purity aluminum-based alloy and comprises 0.3%-0.6% of Mg, 0.1%-0.3% of Zn, 0.05%-0.15% of Cu, 0.05%-0.2% of Mn, smaller than or equal to 0.1% of Si, smaller than or equal to 0.1% of Fe, 0.01%-0.05% of Ti and the balance aluminum, and the thickness of the aluminum foil material ranges from 8 micrometers to 20 micrometers. A conductive enhancement layer and an anti-corrosion layer are arranged on the surface of the aluminum foil, and graphene or carbon nanotubes and titanium dioxide or oxidation are adopted respectively. The preparation method comprises the steps of alloy smelting, hot rolling and cold rolling, annealing treatment, surface roughening and passivation and coating deposition and curing. By optimizing the surface microstructure, the uniformity and adhesive force of the coating are remarkably improved. The obtained aluminum foil material has high conductivity, high mechanical strength and corrosion resistance, can meet the high-performance requirements of energy storage equipment such as lithium ion batteries and supercapacitors, and is efficient and environment-friendly in preparation process and suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the field of preparation of aluminum foil materials, and more specifically to an aluminum foil material for high-density energy storage equipment and a preparation process thereof. Background Art

[0002] Due to its excellent conductivity, lightweight and good processing properties, aluminum foil materials are widely used in high-density energy storage equipment (such as lithium-ion batteries and supercapacitors) as the core material of electrode current collectors. However, with the continuous improvement of the performance of energy storage equipment, higher requirements have been put forward for the comprehensive performance of aluminum foil materials. The prior art shows obvious shortcomings in the following aspects:

[0003] ① It is difficult to achieve a balance between conductivity and mechanical properties. The conductivity of existing aluminum foil materials decreases significantly while the strength increases.

[0004] ② The material’s corrosion resistance is insufficient, especially its stability is poor in long-term, highly corrosive environments, which seriously affects the life of the energy storage equipment.

[0005] ③The surface treatment process is difficult to control precisely, resulting in unsatisfactory adhesion and uniformity of the coating, which cannot adapt to complex environmental requirements.

[0006] ④ The process is complex and not environmentally friendly, which limits the large-scale production and application of the material.

[0007] Therefore, further improvements are needed on aluminum foil used in energy storage devices. Summary of the invention

[0008] In order to solve the shortcomings of the prior art, an aluminum foil material for high-density energy storage equipment and a preparation process thereof are provided. The specific scheme is as follows:

[0009] An aluminum foil material for high-density energy storage equipment, the aluminum foil material consists of the following components, as mass percentage: Al: margin; Mg: 0.3-0.6%; Zn: 0.1-0.3%; Cu: 0.05-0.15%; Mn: 0.05-0.2%; Si: ≤0.1%; Fe: ≤0.1%; Ti: 0.01-0.05%. The thickness of the aluminum foil material is 8-20 μm, and a conductive reinforcement layer and an anti-corrosion layer are provided on its surface.

[0010] Furthermore, the conductive enhancement layer is composed of graphene or carbon nanotubes, and the coating thickness is 100-200nm; the anti-corrosion layer is composed of ceramic-based nanomaterials, and the coating thickness is 50-100nm.

[0011] Furthermore, the ceramic-based nanomaterial is one or a combination of titanium dioxide or aluminum oxide.

[0012] A preparation process of an aluminum foil material for a high-density energy storage device comprises the following steps:

[0013] S1. Aluminum alloy smelting: melt high-purity aluminum at a melting temperature of 750-780℃; add magnesium, zinc, copper, manganese, silicon and titanium respectively, use argon or nitrogen protection, let it stand for degassing and then cast it into aluminum ingots.

[0014] S2. Aluminum ingot rolling: The aluminum ingot is hot rolled to a thickness of 3-5 mm; cold rolled to a target thickness of 8-20 μm, and the surface roughness is controlled at the same time;

[0015] S3. Annealing treatment: Annealing under nitrogen protection at 300-350℃ for 2-3 hours to improve flexibility and uniformity.

[0016] S4. Surface modification: Use 5-10 wt% NaOH solution to clean the surface of the aluminum foil at 40-50°C for a time of 5-10 minutes; use an acid solution to roughen the surface of the aluminum foil for a time of 10-15 minutes to form a microporous structure with a pore size of 0.1-0.5μm; passivation treatment uses zirconium salt or titanium salt solution, with a temperature of 30-40°C for a time of 5-10 minutes;

[0017] S5. Coating deposition: The conductive reinforcement layer is deposited by spraying or electrophoresis by graphene or carbon nanotube dispersion, with a coating thickness of 100-200nm; the anti-corrosion layer is prepared by spin coating by titanium dioxide sol, with a coating thickness of 50-100nm.

[0018] S6. Coating curing: The coated aluminum foil is cured at 200-250°C for 30-60 minutes.

[0019] Furthermore, the hot rolling temperature in S2 is 400-450°C.

[0020] Furthermore, the roughness in S2 is controlled to be 0.1-0.2 μm.

[0021] Furthermore, the acidic solution in S4 is 10-15wt% HCl or H2SO4.

[0022] Furthermore, the concentration of the dispersion used in the conductive enhancement layer in S5 is 1-5 mg / mL.

[0023] Beneficial effects:

[0024] This patent provides an aluminum foil material and its preparation process for high-density energy storage devices. By optimizing the aluminum alloy composition and surface treatment process, the following beneficial effects are achieved:

[0025] (1) The resistivity of aluminum foil is as low as 2.62×10 -8Ω·m, meets the needs of high-efficiency energy transmission of high-density energy storage equipment. The conductive reinforcement layer uses graphene or carbon nanotubes, which effectively improves the surface conductivity of the material and further optimizes the charge and discharge efficiency of energy storage equipment.

[0026] (2) The optimized alloy composition significantly improves the tensile strength and elongation of the aluminum foil, and improves its strength and flexibility while keeping the material lightweight. The precise control of hot rolling and annealing treatment enables the aluminum foil to exhibit excellent formability and dimensional stability during processing, avoiding breakage and deformation during processing. By adding Zn, Mn and an appropriate amount of Ti elements, and using a nano-coating of titanium dioxide or aluminum oxide as the anti-corrosion layer, the corrosion rate of the material in the electrolyte environment is greatly reduced, providing a guarantee for the long-term use of high-density energy storage devices. The surface roughening and passivation treatment forms a microporous structure with a pore size of 0.1-0.5μm, which effectively improves the adhesion of the conductive enhancement layer and the anti-corrosion layer, allowing the coating to remain stable under harsh environments such as high temperature and high humidity. DETAILED DESCRIPTION

[0027] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with examples. The examples are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0028] Embodiment 1:

[0029] A preparation process of aluminum foil material for high-density energy storage equipment comprises the following steps: aluminum alloy smelting:

[0030] High purity aluminum (purity ≥ 99.99%) is heated to 760°C to melt.

[0031] Alloying elements are added in the following proportions:

[0032] Magnesium (Mg): 0.4%;

[0033] Zinc (Zn): 0.2%;

[0034] Copper (Cu): 0.1%;

[0035] Manganese (Mn): 0.1%;

[0036] Silicon (Si): 0.08%;

[0037] Iron (Fe): 0.08%;

[0038] Titanium (Ti): 0.03%.

[0039] During the smelting process, argon gas is used to prevent oxidation. After stirring evenly, it is left to stand for 20 minutes for degassing and finally cast into aluminum ingots.

[0040] Aluminum ingot rolling:

[0041] The aluminum ingots are hot rolled (temperature 420°C) to a thickness of 4 mm.

[0042] Cold rolling was performed to a target thickness of 12 μm, and the surface roughness was controlled, with a roughness Ra value of 0.15 μm.

[0043] Annealing treatment:

[0044] The rolled aluminum foil was annealed under nitrogen protection at a temperature of 320°C for 2.5 hours to improve flexibility and uniformity.

[0045] Surface modification:

[0046] Cleaning: Use 7wt% NaOH solution at 45°C for 8 minutes to remove the surface oxide layer; rinse with deionized water.

[0047] Roughening: The surface was roughened using a 12 wt % H 2 SO 4 solution for 12 minutes to form a microporous structure with a pore size of 0.3 μm; and rinsed with deionized water.

[0048] Passivation: Immersed in zirconium salt solution (concentration 0.2 mol / L) at 35°C for 7 minutes to form a passivation layer with a thickness of 70 nm.

[0049] Coating Deposition:

[0050] Conductive enhancement layer: Graphene dispersion (concentration 3 mg / mL) was used for electrophoretic deposition, and the coating thickness was 150 nm.

[0051] Anti-corrosion layer: Titanium dioxide sol (TiO2 concentration 3wt%) was used and prepared by spin coating with a rotation speed of 2000rpm and a coating thickness of 70nm.

[0052] Coating curing:

[0053] The coated aluminum foil material was cured at 230°C for 45 minutes to form a stable composite coating.

[0054] Example 2

[0055] A preparation process of aluminum foil material for high-density energy storage equipment comprises the following steps: aluminum alloy smelting:

[0056] The melting temperature was set at 770°C, and the following alloying elements were added to the high purity aluminum:

[0057] Magnesium (Mg): 0.5%;

[0058] Zinc (Zn): 0.25%;

[0059] Copper (Cu): 0.12%;

[0060] Manganese (Mn): 0.18%;

[0061] Silicon (Si): 0.09%;

[0062] Iron (Fe): 0.09%;

[0063] Titanium (Ti): 0.04%.

[0064] Use nitrogen protection, stir evenly and let it stand for 15 minutes, and use a ceramic filter to remove impurities.

[0065] Aluminum ingot rolling:

[0066] The hot rolling temperature is 430°C, and the aluminum ingot is processed to a thickness of 3.5 mm.

[0067] Cold rolled to target thickness of 10 μm, surface roughness Ra value of 0.12 μm.

[0068] Annealing treatment:

[0069] The rolled aluminum foil was heated to 340°C under nitrogen protection for 3 hours.

[0070] Surface modification:

[0071] Cleaning: Use 6wt% NaOH solution at 40℃ for 6 minutes to remove surface contaminants.

[0072] Roughening: 10 wt % HCl solution was used for roughening for 15 minutes to form a microporous structure with a pore size of 0.4 μm.

[0073] Passivation: Use titanium salt solution (concentration 0.3 mol / L), temperature 30°C, time 6 minutes, and form a passivation layer with a thickness of 60 nm.

[0074] Coating Deposition:

[0075] Conductive enhancement layer: A carbon nanotube dispersion (concentration 4 mg / mL) was used and deposited by spraying technology, with a coating thickness of 200 nm.

[0076] Anti-corrosion layer: A mixed sol of titanium dioxide and aluminum oxide (ratio 1:1, concentration 4 wt%) was used and prepared by spin coating, with a coating thickness of 80 nm.

[0077] Coating curing:

[0078] The curing temperature is 220°C and the curing time is 40 minutes.

[0079] Example 3

[0080] A preparation process of aluminum foil material for high-density energy storage equipment comprises the following steps: aluminum alloy smelting:

[0081] Melt high purity aluminum to 750℃ and add:

[0082] Magnesium (Mg): 0.3%;

[0083] Zinc (Zn): 0.15%;

[0084] Copper (Cu): 0.08%;

[0085] Manganese (Mn): 0.05%;

[0086] Silicon (Si): 0.06%;

[0087] Iron (Fe): 0.05%;

[0088] Titanium (Ti): 0.02%.

[0089] Nitrogen protection is used during the smelting process, and the mixture is allowed to stand for degassing after being stirred evenly.

[0090] Aluminum ingot rolling:

[0091] The hot rolling temperature is 410℃ and the thickness is 5mm.

[0092] Cold rolled to target thickness of 15 μm, and controlled surface roughness of 0.18 μm.

[0093] Annealing treatment:

[0094] The aluminum foil was heated to 330°C under nitrogen protection for 2 hours.

[0095] Surface modification:

[0096] Cleaning: Use 5 wt % NaOH solution at 42°C for 7 minutes.

[0097] Roughening: 13 wt % HCl solution was used for roughening for 12 minutes, and the pore size of the microporous structure was 0.2 μm.

[0098] Passivation: Immerse in a mixed solution of zirconium salt and titanium salt (ratio 2:1) at 37°C for 8 minutes to form a 75nm passivation layer.

[0099] Coating Deposition:

[0100] Conductive enhancement layer: graphene dispersion (concentration 2 mg / mL), deposited by electrophoresis, coating thickness 120 nm.

[0101] Anti-corrosion layer: Titanium dioxide sol is used and deposited by spraying, with a coating thickness of 60nm.

[0102] Coating curing:

[0103] Curing temperature: 250℃, time: 35 minutes.

[0104] The aluminum foil materials obtained in Examples 1 to 3 were subjected to performance testing, and the test data are as follows:

[0105]

[0106]

[0107] It can be seen from the above table that the aluminum foil material obtained in the embodiment has been enhanced in various properties.

[0108] As a further improvement, the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An aluminum foil material for high-density energy storage equipment, characterized in that: The aluminum foil material consists of the following components, expressed in mass percentage: Al: balance; Mg: 0.3-0.6%; Zn: 0.1-0.3%; Cu: 0.05-0.15%; Mn: 0.05-0.2%; Si: ≤0.1%; Fe: ≤0.1%; Ti: 0.01-0.05%. The thickness of the aluminum foil material is 8-20 μm, and a conductive enhancement layer and an anti-corrosion layer are arranged on the surface thereof.

2. The aluminum foil material for high-density energy storage device according to claim 1, characterized in that: The conductive enhancement layer is composed of graphene or carbon nanotubes, and the coating thickness is 100-200nm; the anti-corrosion layer is composed of ceramic-based nanomaterials, and the coating thickness is 50-100nm.

3. The aluminum foil material for high-density energy storage device according to claim 1, characterized in that: The ceramic-based nanomaterial is one or a combination of titanium dioxide or aluminum oxide.

4. The process for preparing an aluminum foil material for a high-density energy storage device according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Aluminum alloy smelting: melt high-purity aluminum at a melting temperature of 750-780℃; add magnesium, zinc, copper, manganese, silicon and titanium respectively, use argon or nitrogen protection, let it stand for degassing and then cast it into aluminum ingots. S2. Aluminum ingot rolling: The aluminum ingot is hot rolled to a thickness of 3-5 mm; cold rolled to a target thickness of 8-20 μm, and the surface roughness is controlled at the same time; S3. Annealing treatment: Annealing under nitrogen protection at 300-350℃ for 2-3 hours to improve flexibility and uniformity. S4, surface modification: using 5-10wt% NaOH solution to clean the surface of the aluminum foil at 40-50°C for 5-10 minutes; The surface of the aluminum foil is roughened with an acidic solution for 10-15 minutes to form a microporous structure with a pore size of 0.1-0.5 μm; the passivation treatment is carried out with a zirconium salt or titanium salt solution at a temperature of 30-40°C for 5-10 minutes; S5. Coating deposition: The conductive enhancement layer is prepared by spraying or electrophoretic deposition of graphene or carbon nanotube dispersion, and the coating thickness is 100-200nm; the anti-corrosion layer is prepared by spin coating of titanium dioxide sol, and the coating thickness is 50-100nm. S6. Coating curing: The coated aluminum foil is cured at 200-250°C for 30-60 minutes.

5. The process for preparing an aluminum foil material for a high-density energy storage device according to claim 3, characterized in that: The hot rolling temperature in S2 is 400-450°C.

6. The process for preparing an aluminum foil material for a high-density energy storage device according to claim 3, characterized in that: The roughness in S2 is controlled to be 0.1-0.2 μm.

7. The process for preparing an aluminum foil material for a high-density energy storage device according to claim 3, characterized in that: The acidic solution in S4 is 10-15wt% HCl or H2SO4.

8. The process for preparing an aluminum foil material for a high-density energy storage device according to claim 3, characterized in that: The concentration of the dispersion used in the conductive enhancement layer in S5 is 1-5 mg / mL.

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