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CN-122025415-A - Sintered aluminum foil and preparation method thereof

CN122025415ACN 122025415 ACN122025415 ACN 122025415ACN-122025415-A

Abstract

The present disclosure provides a sintered aluminum foil and a method of preparing the same, the method comprising preparing aluminum powder slurry and composite slurry; spraying aluminum powder slurry on a substrate aluminum foil to form a first coating, spraying the composite slurry on the first coating to form a second coating and obtain a coated aluminum foil, and performing glue discharging treatment and sintering treatment on the coated aluminum foil to obtain a sintered aluminum foil. By forming the first coating and the second coating on the substrate aluminum foil and then sintering, the uniformity of the coating is improved, and the specific capacity of the sintered aluminum foil is improved.

Inventors

  • LIU HUI
  • WANG CHEN
  • LI ZHONG
  • PU YU
  • CHENG HENGYANG

Assignees

  • 南通海星电子股份有限公司
  • 南通海一电子有限公司
  • 四川中雅科技有限公司

Dates

Publication Date
20260512
Application Date
20260416

Claims (12)

  1. 1. A method of making a sintered aluminum foil comprising: Preparing aluminum powder slurry and composite slurry; spraying the aluminum powder slurry on a substrate aluminum foil to form a first coating; spraying the composite slurry on the first coating to form a second coating and obtain a coated aluminum foil; And (3) performing glue discharging treatment and sintering treatment on the coated aluminum foil to obtain the sintered aluminum foil.
  2. 2. The method of claim 1, wherein the first coating and the second coating are different in thickness.
  3. 3. The method of claim 2, wherein the thickness of the second coating is greater than the thickness of the first coating.
  4. 4. A method according to claim 3, wherein the thickness ratio of the second coating layer and the first coating layer is from 6:4 to 9:1.
  5. 5. The method according to any one of claims 1 to 4, wherein the total thickness of the first and second coating layers is from 90 μm to 120 μm.
  6. 6. The method of any one of claims 1 to 4, wherein the composite slurry contains additional metal powder comprising one or more of titanium powder, zirconium powder, hafnium powder and lanthanum powder.
  7. 7. The method of claim 6, wherein the composite slurry comprises a powder, a second binder, and a second solvent, the powder comprising a second aluminum powder and the additional metal powder, the mass ratio of the second binder to the powder being 1:10-100, the mass ratio of the powder to the second solvent being 1g:1-10ml, the mass ratio of the second aluminum powder to the additional metal powder being 1-20:1.
  8. 8. The method of any one of claims 1 to 4, wherein the aluminum powder slurry comprises a first aluminum powder, a first binder, and a first solvent, the mass ratio of the first binder to the first aluminum powder is 1:10-100, and the ratio of the first aluminum powder to the first solvent is 1g:1-10ml.
  9. 9. The method of claim 8, wherein the first aluminum powder has a particle size of 1 to 5 μm, the first binder comprises one or more of epoxy, polyvinylidene fluoride, carboxymethyl cellulose, and acrylic resin, and the first solvent comprises one or more of absolute ethyl alcohol, butyl acetate, and N-methyl pyrrolidone.
  10. 10. The method of claim 7, wherein at least one of: the particle size of the second aluminum powder is 1-5 μm; the particle size of the additional metal powder is 1-5 μm; The second binder comprises one or more of epoxy resin, polyvinylidene fluoride, carboxymethyl cellulose and acrylic resin; the second solvent comprises one or more of absolute ethyl alcohol, butyl acetate and N-methyl pyrrolidone; The thickness of the coated aluminum foil is 120-150 μm.
  11. 11. The method according to any one of claims 1 to 4, wherein the glue removal treatment comprises placing the coated aluminum foil in a vacuum oven and evacuating to below 10 -2 Pa, followed by heating to 350-450 ℃ and maintaining for 1-5 hours at a heating rate of less than 20 ℃ per minute; The sintering treatment comprises heating to 550-650 ℃ and preserving heat for 1-5h.
  12. 12. Sintered aluminum foil, characterized in that it is a sintered aluminum foil prepared according to the method of any one of claims 1 to 11.

Description

Sintered aluminum foil and preparation method thereof Technical Field The disclosure relates to the field of capacitors, in particular to a sintered aluminum foil and a preparation method thereof. Background In recent years, powder sintered aluminum foil has become a current research hot spot due to the characteristics of ultra-high specific volume and small environmental pollution. The technical route of the powder sintered aluminum foil is opposite to the traditional corrosion foil, aluminum powder particles are adhered to the surface of a substrate aluminum foil by additive manufacturing and sintered and solidified, the gaps among the particles are used for forming a larger specific surface area than the traditional corrosion foil, the electrical property of the anode foil is greatly improved, and compared with the corrosion foil production line, a large amount of acid liquor and electric quantity are required to be applied, and the powder sintered aluminum foil manufacturing process has great advantages in the aspects of environmental protection and energy conservation. However, powder sintered aluminum foil still has several problems in the development and manufacturing process. The general process route of powder sintering aluminum foil is coating-sintering-forming, wherein coating refers to a process of uniformly covering the surface of a substrate aluminum foil with a mixed slurry containing aluminum powder and a binder. The current mainstream coating method is that a die head extrudes the slurry and strickles the slurry or transfers the slurry to the surface of an aluminum foil by using an intermediate roller, wherein the die head needs to precisely control the pressure of a die cavity and the distance between the die head and the aluminum foil during coating, and the slurry has proper leveling property and drying speed, and the die head needs to have a complex mechanical structure and has higher viscosity requirement on the slurry. In addition, if the thickness of the coating layer needs to be changed, besides adjusting the mechanical distance, the slurry proportion needs to be adjusted, and the adjustment precision is poor. The current capacitor industry places more demands on anode aluminum foil, such as ultra-high specific volume, lower thickness, flatter surfaces, etc. These customization requirements often require bilayer or even multilayer coatings to achieve. The two methods have higher difficulty in realizing multilayer coating and higher equipment requirement. In addition, the specific capacity of the sintered aluminum foil prepared by the current method still has room for improvement. Disclosure of Invention The embodiment of the disclosure provides a method for preparing a sintered aluminum foil, which comprises the steps of preparing aluminum powder slurry and composite slurry, spraying the aluminum powder slurry on a substrate aluminum foil to form a first coating, spraying the composite slurry on the first coating to form a second coating and obtain a coated aluminum foil, and performing glue discharging treatment and sintering treatment on the coated aluminum foil to obtain the sintered aluminum foil. In some embodiments, the thickness of the first coating and the second coating are different. In some embodiments, the thickness of the second coating is greater than the thickness of the first coating. In some embodiments, the thickness ratio of the second coating to the first coating is from 6:4 to 9:1. In some embodiments, the first coating and the second coating have a total thickness of 90 μm to 120 μm. In some embodiments, the composite slurry contains additional metal powders including one or more of titanium powder, zirconium powder, hafnium powder, and lanthanum powder. In some embodiments, the aluminum powder slurry includes a first aluminum powder, a first binder, and a first solvent, the mass ratio of the first binder to the first aluminum powder is 1:10-100, and the ratio of the first aluminum powder to the first solvent is 1g:1-10ml. In some embodiments, the composite paste further comprises a second aluminum powder, the mass ratio of the second aluminum powder to the additional metal powder being 1-20:1. In some embodiments, the composite slurry includes a powder including a second aluminum powder and an additional metal powder, a second binder, and a second solvent, the mass ratio of the second binder to the powder being 1:10-100, and the ratio of the powder to the second solvent being 1g:1-10ml. In some embodiments, the first aluminum powder has a particle size of 1 μm to 5 μm, the first binder comprises one or more of epoxy, polyvinylidene fluoride, carboxymethyl cellulose, and acrylic resin, and the first solvent comprises one or more of absolute ethyl alcohol, butyl acetate, and N-methyl pyrrolidone. In some embodiments, the second aluminum powder has a particle size of 1 μm to 5 μm and the additional metal powder has a particle size of 1 μm to 5 μm, the second bind