Method for manufacturing polyimide-aluminum composite foil

Abstract

The present invention discloses a method for producing polyimide-aluminum composite foil. The method includes an aluminum foil heat treatment step, an aluminum foil cooling step, an etched foil production step, a hole-expanded foil production step, a polyimide composite layer production step, and a surface cleaning and drying treatment. The pre-treatment liquid used in the polyimide composite layer production step is a mixture of 4,4'-diaminodiphenyl ether, N,N-dimethylacetamide and tetra-n-hexylammonium benzoate, and the post-treatment liquid used is a mixture of sulfuric acid, hydrochloric acid, 4,4'-diaminodiphenyl ether, N,N-dimethylacetamide and tetra-n-hexylammonium benzoate. As a result, the polyimide composite layer after molding can be stably attached to the outer surface of the etched foil, and the bending strength of the electrode foil can be improved. In addition, the polyimide composite layer filled inside the etched hole is firmly integrated with the aluminum residual core, which is advantageous for the electrode foil after molding to have a relatively high dielectric constant and area-specific capacitance.

Description

Technical Field

[0001] The present invention belongs to the field of electrode foil manufacturing technology, and particularly relates to a method for manufacturing a polyimide-aluminum composite foil.

Background Art

[0002] Due to the country's power restrictions and the promotion of energy-saving policies, power saving in industrial production has become an urgent task. Due to the low power consumption characteristics, the manufacturing process of chemical machinery based on chemical corrosion has been continuously developed in the industry. For example, Chinese Patent CN113502476B discloses a method for manufacturing an electrode foil for a solid aluminum electrolytic capacitor. Specifically, it includes steps of immersing an aluminum foil in a hydrochloric acid solution, immersing it in an acidic solution and applying a high-frequency pulsed current for preliminary electrolysis, sequentially performing first electrolytic corrosion and second electrolytic corrosion, repeating the first electrolytic corrosion and the second electrolytic corrosion at least three times, washing with pure water, washing with a chemical cleaning solution, further washing with pure water, and performing high-temperature heat treatment and cooling. This manufacturing method has the advantages of power saving and a high area specific capacitance of the manufactured electrode foil. However, a large number of corrosion holes remain in the manufactured electrode foil, resulting in a decrease in structural strength. In particular, the number of bending times under the rated load does not meet the quality inspection standards, and the manufacturing period is long, indirectly increasing the production cost and manufacturing cost. Also, after manufacturing the corrosion foil, in order to avoid surface oxidation, it is necessary to place it in a vacuum environment or an inert gas environment, significantly increasing the heat treatment cost. Therefore, it is necessary to solve the above problems.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Considering the problems and drawbacks of the above prior art, the designer of the present invention collected relevant information, evaluated and considered many aspects, and further continuously experimented and modified by technicians with many years of research and development experience in this industry. Finally, a method for manufacturing a polyimide-aluminum composite foil was found.

Means for Solving the Problem

[0004] To solve the above problems, a method for manufacturing a polyimide-aluminum composite foil is provided, which includes a heat treatment step S1 of putting an aluminum foil with a purity of 99.9% or more into an oven and performing a heat treatment at a temperature of 480 to 520 °C for 3 to 5 minutes; a cooling step S2 of placing the aluminum foil treated in step S1 in the air and allowing it to cool naturally; a corroded foil manufacturing step S3 of immersing the aluminum foil treated in step S2 in a liquid of corrosive acid to form corrosion holes on the surface; a hole expansion foil manufacturing step S4 of immersing the corroded foil obtained in step S3 in a hole expansion solution to expand the corrosion holes, and the pore diameter of the treated corrosion holes is 0.1 μm or more; a polyimide composite layer manufacturing step S5 including the following sub-steps: step S51 of immersing the hole expansion foil obtained in step S4 in a pretreatment tank, and the pretreatment liquid used is a pretreatment liquid formed by mixing 0.5 to 1 mol / L of 4,4'-diaminodiphenyl ether, 0.5 to 1 mol / L of N,N-dimethylacetamide, and 0.5 to 1 mol / L of tetra-n-hexylammonium benzoate, the temperature is controlled at 150 to 180 °C, and the immersion time is controlled at 30 to 60 S to form a composite foil; step S52 of taking out the composite foil obtained in step S51 from the pretreatment tank and placing it in the air until the polyimide composite layer is solidified and formed; a step S6 of immersing the composite foil obtained in step S5 in a post-treatment tank, and the post-treatment liquid used is a post-treatment liquid formed by mixing 0.3 to 0.5 mol / L of sulfuric acid, 1 to 1.5 mol / L of hydrochloric acid, 0.3 to 0.6 mol / L of 4,4'-diaminodiphenyl ether, 0.25 to 0.6 mol / L of N,N-dimethylacetamide, and 0.2 to 0.3 mol / L of tetra-n-hexylammonium benzoate, the temperature is controlled at 68 to 75 °C, and the time is controlled at 3 to 5 minutes, then taking out the composite foil from the post-treatment tank and placing it in the air for 10 to 15 minutes; a step S7 of immersing the composite foil treated in step S6 in pure water and washing it for 2 minutes or more; and a step S8 of drying the composite foil treated in step S7 to obtain a polyimide-aluminum composite foil.

[0005] As a further improvement of the technical solution disclosed in the present invention, in step S51, the pretreatment liquid is maintained in a high-frequency vibration state or a high-frequency disturbance state.

[0006] As a further improvement of the technical solution disclosed in the present invention, a plurality of high-frequency vibrators are uniformly arranged on the bottom and the surrounding side walls of the pretreatment tank, and the vibration frequency is controlled to be 50 - 150 Hz.

[0007] As a further improvement of the technical solution disclosed in the present invention, when step S6 is executed, an electric current is passed through the post-treatment liquid, and the current density is controlled to be 0.03 - 0.08 A / cm 2 ².

[0008] As a further improvement of the technical solution disclosed in the present invention, in step S3, the corrosive acid liquid used is a mixed solution of hydrochloric acid 11.03 mo / L: sulfuric acid 7.5 mol / L = 2:1, and the temperature is controlled to be 50 - 70 °C.

[0009] As a further improvement of the technical solution disclosed in the present invention, in step S4, the hole-expanding solution used is a mixed solution of sulfuric acid 0.5 - 1 mol / L and hydrochloric acid 1.5 - 2 mol / L, the temperature is controlled to be 68 - 75 °C, and the time is controlled to be 3 - 5 min.

[0010] As a further improvement of the technical solution disclosed in the present invention, in step S4, the hole-expanding solution used is a mixed solution of sulfuric acid 0.5 - 1 mol / L and hydrochloric acid 1.5 - 2 mol / L, the temperature is controlled to be 68 - 75 °C, and hole expansion is performed at a current density of 1 - 2 A / cm 2 ², and the time is controlled to be 1 - 1.5 min.

Advantages of the Invention

[0011] In actual industrial applications, the manufacturing process of the polyimide-aluminum composite foil achieves at least the following beneficial effects.

[0012] 1) In the electrochemical corrosion process, 0.5 - 1 mol / L of 4,4'-diaminodiphenyl ether, 0.5 - 1 mol / L of N,N-dimethylacetamide, and tetra-n-hexylammonium benzoate are likely to polymerize / composite on the surface of the aluminum foil to form a polyimide composite layer, and the polyimide composite layer can also stably adhere to the outer surface of the corroded foil, which helps to improve the bending strength of the electrode foil (i.e., more bending times can be achieved at the rated load).

[0013] 2) In the polyimide composite layer manufacturing step, 0.5 - 1 mol / L of 4,4'-diaminodiphenyl ether, 0.5 - 1 mol / L of N,N-dimethylacetamide, and tetra-n-hexylammonium benzoate penetrate into the corrosion pores. After solidification and forming, they firmly integrate with the aluminum residual core. According to well-known techniques, the polyimide composite layer itself has a dielectric constant of 4.0 at 10 3 Hz and has a high insulation property with a dielectric loss of only 0.004 - 0.007, which is advantageous for the formed electrode foil to have a relatively high dielectric constant and area specific capacitance.

[0014] 3) In the polyimide composite layer manufacturing step, the post-treatment liquid used is a mixture of sulfuric acid, hydrochloric acid, 4,4'-diaminodiphenyl ether, N,N-dimethylacetamide, and tetra-n-hexylammonium benzoate. Compared with 4,4'-diaminodiphenyl ether, N,N-dimethylacetamide, and tetra-n-hexylammonium benzoate in the pretreatment liquid, the content is significantly reduced, and it can repair the defects of the polyimide composite layer adhering to the surface of the aluminum foil, ensure the overall continuity of the polyimide composite layer, and realize that the surface quality of the manufactured electrode foil is good.

[0015] 4) Since the polyimide composite layer can be cooled and solidified at room temperature to form, the formation process becomes unnecessary (in the conventional manufacturing method, first, the aluminum foil is corroded, and then the formation process is carried out), the manufacturing cost of the electrode foil can be significantly reduced, and the manufacturing time / cycle can be shortened.

Embodiments for Carrying Out the Invention

[0016] To deepen the understanding of the present invention, the present invention will be described in more detail with reference to the following embodiments. It should be noted that these examples are only used to explain the present invention and do not limit the protection scope of the present invention. In addition, it should be understood that the content not described in the detailed description of the present invention is a general method unless otherwise specified.

[0017] Comparative Example (extracted from paragraphs 23 to 32 of the specification of Chinese Patent CN113502476B) Soft aluminum with a purity of 99.98% and a thickness of 120 μm is immersed in a 0.1% hydrochloric acid solution at a temperature of 70°C for 2 minutes. The aluminum foil after pretreatment is immersed in a 0.5% phosphoric acid solution and pre-electrolyzed with a high-frequency pulsed current at a temperature of 40°C for 30 seconds.

[0018] The pre-electrolyzed aluminum foil is immersed in a mixed aqueous solution for the first electrolytic corrosion. A sine-wave alternating current with a frequency of 40 Hz is applied, the reaction temperature is 40°C, and the reaction time is 2 minutes. Then, it is immersed in a middle-treatment mixed aqueous solution for chemical corrosion. Here, the reaction temperature is 60°C and the reaction time is 25 seconds. And then, it is immersed in a mixed aqueous solution for the second electrolytic corrosion. A square-wave alternating current with a frequency of 90 Hz is applied. Here, the reaction temperature is 20°C and the reaction time is 2 minutes.

[0019] The above steps of the first electrolytic corrosion and the steps of the first electrolytic corrosion are each repeated 3 times.

[0020] The corroded foil is immersed in pure water and washed with running water for 2 minutes.

[0021] The corroded foil is immersed in a chemical cleaning solution for post-treatment cleaning. Here, the temperature of the post-treatment cleaning solution is 60°C and the reaction time is 4 minutes.

[0022] A treatment of washing in 30°C pure water is performed. Here, the washing time is 8 minutes.

[0023] Put the aluminum foil into an oven and perform heat treatment at 520 °C. The heat treatment process is carried out in an inert gas protection atmosphere or in a vacuum. After 40 s of treatment, a product is obtained.

[0024] According to specific experimental results, the breakdown voltage performance of the corroded aluminum foil is only 530 V, the areal specific capacitance is 119.88, and the CV performance is 564.8 μF·V·cm -2 The breakdown voltage rise time in warm water (hydration process) is 16 min, and the number of limit bending times is 33 times. Here, the breakdown voltage rise time in warm water means that it usually takes a long time to measure the corrosion resistance performance at room temperature. Instead of the room temperature environment, under high temperature conditions (for example, in water at 95 ± 1 °C under standard atmospheric pressure), the film is formed (the film is formed by corrosion), the resistance value changes, and a specified current is passed through the formed foil with such a changing resistance value until the applied voltage to the formed foil rises to 90% of the breakdown voltage (film breakdown voltage).

[0025] (Example 1) The manufacturing method of the polyimide-aluminum composite foil includes the following steps.

[0026] S1. Heat treatment step: Put the aluminum foil with a purity of 99.9% or more into an oven and control the temperature at 480 - 520 °C and the time at 3 - 5 min for heat treatment.

[0027] S2. Cooling step: Place the aluminum foil treated in step S1 in the air and let it cool naturally.

[0028] S3. Corroded foil manufacturing step: Immerse the aluminum foil treated in step S2 in a corrosive acid liquid (corrosion solution) to form corrosion holes on the surface. The used corrosive acid liquid is a mixed solution of hydrochloric acid 11.03 mo / L: sulfuric acid 7.5 mol / L = 2:1, and the temperature is controlled at 50 - 70 °C.

[0029] S4. Hole-expanding Foil Manufacturing Step: Immerse the etched foil obtained in Step S3 in a hole-expanding solution to expand the etched holes. The pore diameter of the etched holes after treatment is 0.1 μm or more. The hole-expanding solution used is a mixed solution of 0.5 - 1 mol / L sulfuric acid and 1.5 - 2 mol / L hydrochloric acid, the temperature is controlled at 68 - 75 °C, and the time is controlled at 3 - 5 min.

[0030] S5. Polyimide Composite Layer Manufacturing Step includes the following sub-steps.

[0031] S51. Immerse the hole-expanded foil obtained in Step S4 in a pretreatment tank. The pretreatment solution used is a mixture of 0.5 - 1 mol / L 4,4'-diaminodiphenyl ether, 0.5 - 1 mol / L N,N-dimethylacetamide, and 0.5 - 1 mol / L tetra-n-hexylammonium benzoate. The temperature is controlled at 150 - 180 °C, and the immersion time is controlled at 30 - 60 s to form a composite foil.

[0032] S52. Take out the composite foil obtained in Step S51 from the pretreatment tank and place it in the air until the polyimide composite layer is solidified.

[0033] S6. Immerse the composite foil obtained in Step S5 in a post-treatment tank. The post-treatment solution used is a mixture of 0.3 - 0.5 mol / L sulfuric acid, 1 - 1.5 mol / L hydrochloric acid, 0.3 - 0.6 mol / L 4,4'-diaminodiphenyl ether, 0.25 - 0.6 mol / L N,N-dimethylacetamide, and 0.2 - 0.3 mol / L tetra-n-hexylammonium benzoate. The temperature is controlled at 68 - 75 °C, and the time is controlled at 3 - 5 min. Then, take out the composite foil from the post-treatment tank and leave it in the air for 10 - 15 min.

[0034] S7. Immerse the composite foil treated in Step S6 in pure water for rinsing, and the washing time is 2 min or less.

[0035] S8. Dry the composite foil treated in Step S7 to obtain a polyimide-aluminum composite foil.

[0036] Experiments were carried out, and as a result of verification based on the obtained specific experimental results, compared with the comparative example, the breakdown voltage performance of the corroded aluminum foil was improved to 538 V, the areal specific capacitance was improved to 121.05, the CV performance was improved to 572.5 μF·V·cm -2 and the limit bending times increased to 45 times, and the voltage rise time in warm water was shortened to 8 min.

[0037] The reasons are considered as follows.

[0038] (1) During the electrochemical corrosion process, 0.5 - 1 mol / L of 4,4'-diaminodiphenyl ether, 0.5 - 1 mol / L of N,N-dimethylacetamide and tetra-n-hexylammonium benzoate polymerize / complex in-situ on the surface of the aluminum foil to form a polyimide composite layer, and the polyimide composite layer can stably adhere to the outer surface of the corroded foil, so it can help to improve the bending strength of the electrical foil (that is, the bending strength at the rated load is strong).

[0039] (2) In the polyimide composite layer manufacturing step, 0.5 - 1 mol / L of 4,4'-diaminodiphenyl ether, 0.5 - 1 mol / L of N,N-dimethylacetamide and tetra-n-hexylammonium benzoate may penetrate into the corrosion pores and can be firmly integrated with the aluminum residual core after the subsequent solidification and forming. According to well-known techniques, the polyimide composite layer itself has a dielectric constant of 4.0 at 10 3 Hz and has a high insulation property with a dielectric loss of only 0.004 - 0.007, which is beneficial for the formed electrode foil to have a relatively high dielectric constant and areal specific capacitance.

[0040] 3) In the step of manufacturing the polyimide composite layer, the post-treatment liquid used is a mixture of sulfuric acid, hydrochloric acid, 4,4'-diaminodiphenyl ether, N,N-dimethylacetamide, and tetra-n-hexylammonium benzoate. Compared with 4,4'-diaminodiphenyl ether, N,N-dimethylacetamide, and tetra-n-hexylammonium benzoate in the pre-treatment liquid, the content is significantly reduced, the defects of the polyimide composite layer adhering to the surface of the aluminum foil can be repaired, the overall continuity of the polyimide composite layer can be ensured, and it can be realized that the surface quality of the manufactured electrode foil is good.

[0041] It should be noted that in the conventional method for manufacturing an electrode foil, first, an aluminum foil is corroded and formed, and then a heat treatment process is performed. In Example 1, in the step of manufacturing the polyimide composite layer, a mixed solution of 0.5 to 1 mol / L of 4,4'-diaminodiphenyl ether, 0.5 to 1 mol / L of N,N-dimethylacetamide, and tetra-n-hexylammonium benzoate uniformly adheres to the surface of the aluminum foil to achieve stable forming. Also, in order to avoid the alteration of the polyimide composite layer due to the influence of high temperature, the aluminum foil heat treatment process is performed before the corrosion process. Example 2 The method for manufacturing a polyimide-aluminum composite foil includes the following steps.

[0042] S1. Heat treatment step: Put an aluminum foil with a purity of 99.9% or more into an oven for heat treatment. The temperature is controlled at 480 - 520 °C, and the time is controlled at 3 - 5 min.

[0043] S2. Cooling step: Place the aluminum foil treated in step S1 in the air for natural cooling.

[0044] S3. Corroded foil manufacturing step: Immerse the aluminum foil treated in step S2 in a liquid of corrosive acid to form corrosion holes on the surface. The liquid of corrosive acid used is a mixed solution of hydrochloric acid 11.03 mo / L: sulfuric acid 7.5 mol / L = 2:1, and the temperature is controlled at 50 - 70 °C.

[0045] S4. Etching Hole Expansion Foil Manufacturing Step: The etched foil obtained in step S3 is immersed in an etching hole expansion solution to expand the etched holes. The processed etched holes have a pore diameter of 0.1 μm or more. The etching hole expansion solution used is a mixed solution of 0.5 - 1 mol / L sulfuric acid and 1.5 - 2 mol / L hydrochloric acid, with the temperature controlled at 68 - 75°C and the time controlled at 3 - 5 minutes.

[0046] S5. Polyimide Composite Layer Manufacturing Step includes the following sub - steps.

[0047] S51. The etched hole expansion foil obtained in step S4 is immersed in a pretreatment tank. The pretreatment solution used is a mixture of 0.5 - 1 mol / L 4,4'-diaminodiphenyl ether, 0.5 - 1 mol / L N,N - dimethylacetamide, and 0.5 - 1 mol / L tetra - n - hexylammonium benzoate. The temperature is controlled at 150 - 180°C, the immersion time is controlled at 30 - 60 s to form a composite foil. A plurality of high - frequency oscillators are evenly arranged on the bottom and the surrounding side walls of the pretreatment tank, with the frequency controlled at 50 - 150 Hz, and the pretreatment solution is always maintained in a high - frequency vibration state.

[0048] S52. The composite foil obtained in step S51 is taken out of the pretreatment tank and placed in the air until the polyimide composite layer is solidified.

[0049] S6. The composite foil obtained in step S5 is immersed in a post - treatment tank. The post - treatment solution used is a mixture of 0.3 - 0.5 mol / L sulfuric acid, 1 - 1.5 mol / L hydrochloric acid, 0.3 - 0.6 mol / L 4,4'-diaminodiphenyl ether, 0.25 - 0.6 mol / L N,N - dimethylacetamide, and 0.2 - 0.3 mol / L tetra - n - hexylammonium benzoate. The temperature is controlled at 68 - 75°C and the time is controlled at 3 - 5 minutes. Then, the composite foil is taken out of the post - treatment tank and left in the air for 10 - 15 minutes.

[0050] S7. Immerse the composite foil obtained in step S6 in pure water for washing, and the washing time is 2 min or more.

[0051] S8. Dry the composite foil obtained in step S7 to obtain a polyimide-aluminum composite foil.

[0052] According to the experimental data and experimental results, the breakdown voltage performance of the corroded aluminum foil is 539.8 V, the areal specific capacitance is 123.07, the CV performance is 578.5 μF·V·cm -2 and the limit bending times is 48, and the voltage rise time in warm water is 7.5 min.

[0053] Compared with the experimental data of Example 1, the limit bending times of the corroded aluminum foil and the voltage rise time in warm water are not significantly improved, but the breakdown voltage performance, areal specific capacitance and CV performance are significantly improved. The reason is that in the polyimide composite layer manufacturing step, high-frequency vibration force is always applied to the pretreatment tank. In the polyimide composite layer manufacturing step, 0.5 - 1 mol / L of 4,4'-diaminodiphenyl ether, 0.5 - 1 mol / L of N,N-dimethylacetamide and tetra-n-hexylammonium benzoate are beneficial for invading the corrosion pores, which means that complete penetration of the side walls, that is, the formed polyimide composite layer can completely cover the aluminum residual core, which is also beneficial to the improvement of electrical performance parameters. Example 3 The manufacturing method of the polyimide-aluminum composite foil includes the following steps.

[0054] S1. Heat treatment step: Put an aluminum foil with a purity of 99.9% or more into an oven for heat treatment. (The temperature is controlled at 480 - 520 °C and the time is controlled at 3 - 5 min) S2. Cooling step: Place the aluminum foil treated in step S1 in the air for natural cooling.

[0055] S3. Corrosion foil manufacturing step: Immerse the aluminum foil processed in step S2 into a liquid of corrosive acid to form corrosion holes on the surface. The liquid of corrosive acid used is a mixed solution of hydrochloric acid 11.03 mo / L: sulfuric acid 7.5 mol / L = 2:1, and the temperature is controlled at 50 - 70 °C.

[0056] S4. Hole-expanding foil manufacturing step: Immerse the corrosion foil obtained in step S3 into a hole-expanding solution to expand the corrosion holes. The processed corrosion holes have a pore diameter of 0.1 μm or more. The hole-expanding solution used is a mixed solution of sulfuric acid 0.5 - 1 mol / L and hydrochloric acid 1.5 - 2 mol / L, the temperature is controlled at 68 - 75 °C, and the time is controlled at 3 - 5 min.

[0057] S5. Polyimide composite layer manufacturing step includes the following sub-steps.

[0058] S51. Immerse the hole-expanding foil obtained in step S4 into a pretreatment tank. The pretreatment liquid is a mixture of 4,4'-diaminodiphenyl ether 0.5 - 1 mol / L, N,N-dimethylacetamide 0.5 - 1 mol / L, and tetra-n-hexylammonium benzoate 0.5 - 1 mol / L. The temperature is controlled at 150 - 180 °C, and the immersion time is controlled at 30 - 60 s to manufacture a composite foil. A plurality of high-frequency oscillators are evenly arranged on the bottom and the surrounding side walls of the pretreatment tank, the frequency is controlled at 50 - 150 Hz, and the pretreatment liquid is always maintained in a high-frequency vibration state.

[0059] S52. Take out the composite foil obtained in step S51 from the pretreatment tank and place it in the air until the polyimide composite layer solidifies and is formed.

[0060] S6. Immerse the composite foil obtained in step S5 into a post-treatment tank. The post-treatment solution used is a mixture of 0.3 - 0.5 mol / L sulfuric acid, 1 - 1.5 mol / L hydrochloric acid, 0.3 - 0.6 mol / L 4,4'-diaminodiphenyl ether, 0.25 - 0.6 mol / L N,N-dimethylacetamide, and 0.2 - 0.3 mol / L tetra-n-hexylammonium benzoate. The temperature is controlled at 68 - 75 °C and the time is controlled at 3 - 5 min. During the treatment process, a current is constantly passed through the post-treatment solution, and the current density is controlled at 0.03 - 0.08 A / cm 2 2 and then, take out the composite foil from the post-treatment tank and leave it in the air for 10 - 15 min.

[0061] S7. Wash the composite foil treated in step S6 with pure water, and the washing time is 2 min or more.

[0062] S8. Dry the composite foil treated in step S7 to obtain a polyimide-aluminum composite foil.

[0063] According to the experimental data and experimental results, the breakdown voltage performance of the etched aluminum foil is 539.6 V, the areal specific capacitance is 122.05, the CV performance is 579.3 μF·V·cm -2 -2 , the number of limit bending times is 54, and the voltage rise time in warm water is 6 min.

[0064] When compared with the experimental data of Example 2, the breakdown voltage performance, area specific capacitance, and CV performance of the corrosion-resistant aluminum foil are not significantly improved, but the limit bending times are significantly improved, and it is found that the voltage rise time in warm water is significantly shortened. The reason is that in the polyimide composite layer manufacturing step, the post-treatment liquid is always maintained in a micro-current state, so 4,4'-diaminodiphenyl ether 0.5 - 1 mol / L, N,N-dimethylacetamide 0.5 - 1 mol / L, and tetra-n-hexylammonium benzoate ions are polar, which is beneficial for finding and repairing the defect areas or cracks of the polyimide composite layer (the defect areas or cracks of the polyimide composite layer have a larger potential difference than the non-defect areas). Thereby, it is ensured that the formed polyimide composite layer has good surface quality, can completely wrap the aluminum foil, and it is possible to realize that the thickness values of each region of the formed polyimide composite layer are consistent.

[0065] Finally, according to general knowledge, the polyimide composite layer can be cooled and cured at room temperature for forming. Thereby, the process passing through the formation process (in the conventional method, first, a corrosion process is performed on the aluminum foil, and then the corrosion process is carried out.) is reduced, the manufacturing cost of the electrode foil can be significantly reduced, and the manufacturing time and cycle can be shortened. JPEG0007701998000001.jpg57166

[0066] According to the description of the disclosed embodiments, those skilled in the art can manufacture or use the present invention. Various modifications to these embodiments are easy for those skilled in the art, and the general principles defined in this specification can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown in detail of the invention, but also includes the broadest scope consistent with its principles and features.

Claims

1. A method for manufacturing a polyimide-aluminum composite foil, comprising: A heat treatment step S1 in which an aluminum foil with a purity of 99.9% or more is placed in an oven and heat-treated at a temperature of 480 to 520 °C for 3 to 5 minutes; A cooling step S2 in which the aluminum foil treated in step S1 is placed in air and naturally cooled; A corroded foil manufacturing step S3 in which the aluminum foil treated in step S2 is immersed in a liquid of a corrosive acid to form corrosion holes on the surface; A hole expansion foil manufacturing step S4 in which the corroded foil obtained in step S3 is immersed in a hole expansion solution to expand the corrosion holes, and the pore diameter of the treated corrosion holes is 0.1 μm or more; A polyimide composite layer manufacturing step S5 including the following sub-steps: A step S51 in which the hole-expanded foil obtained in step S4 is immersed in a pretreatment tank, and the pretreatment liquid used is a pretreatment liquid formed by mixing 0.5 to 1 mol / L of 4,4'-diaminodiphenyl ether, 0.5 to 1 mol / L of N,N-dimethylacetamide, and 0.5 to 1 mol / L of tetra-n-hexylammonium benzoate, the temperature is controlled at 150 to 180 °C, and the immersion time is controlled at 30 to 60 s to form a composite foil; A step S52 in which the composite foil obtained in step S51 is taken out of the pretreatment tank and placed in air until the polyimide composite layer is solidified and formed, including the polyimide composite layer manufacturing step S5; A step S6 in which the composite foil obtained in step S5 is immersed in a post-treatment tank, and the post-treatment liquid used is a post-treatment liquid formed by mixing 0.3 to 0.5 mol / L of sulfuric acid, 1 to 1.5 mol / L of hydrochloric acid, 0.3 to 0.6 mol / L of 4,4'-diaminodiphenyl ether, 0.25 to 0.6 mol / L of N,N-dimethylacetamide, and 0.2 to 0.3 mol / L of tetra-n-hexylammonium benzoate, the temperature is controlled at 68 to 75 °C, the time is controlled at 3 to 5 minutes, then the composite foil is taken out of the post-treatment tank and placed in air for 10 to 15 minutes; A step S7 in which the composite foil treated in step S6 is immersed in pure water and washed for 2 minutes or more; A step S8 in which the composite foil treated in step S7 is dried to obtain a polyimide-aluminum composite foil, including a method for manufacturing a polyimide-aluminum composite foil, characterized by the above.

2. The manufacturing method of the polyimide-aluminum composite foil according to claim 1, wherein in step S51, the pretreatment liquid is maintained in a high-frequency vibration state or a high-frequency disturbance state.

3. The manufacturing method of the polyimide-aluminum composite foil according to claim 2, wherein a plurality of high-frequency vibrators are uniformly arranged on the bottom and the surrounding side walls of the pretreatment tank, and the vibration frequency is controlled to be 50 to 150 Hz.

4. When executing step S6, a current is passed through the post-treatment liquid, and the current density is controlled to be 0.03 to 0.08 A / cm ２ The method for manufacturing a polyimide-aluminum composite foil according to claim 1, characterized in that.

5. The manufacturing method of the polyimide-aluminum composite foil according to any one of claims 1 to 4, wherein in step S3, the liquid of the corrosive acid used is a mixed solution of hydrochloric acid 11.03 mo / L: sulfuric acid 7.5 mol / L = 2:1, and the temperature is controlled to be 50 to 70 °C.

6. The manufacturing method of the polyimide-aluminum composite foil according to any one of claims 1 to 4, wherein in step S4, the solution for hole expansion used is a mixed solution of sulfuric acid 0.5 to 1 mol / L and hydrochloric acid 1.5 to 2 mol / L, the temperature is controlled to be 68 to 75 °C, and the time is controlled to be 3 to 5 min.

Images