CN113874971A - Aluminum foil, electrode for aluminum electrolytic capacitor, and method for producing aluminum foil - Google Patents
Aluminum foil, electrode for aluminum electrolytic capacitor, and method for producing aluminum foil Download PDFInfo
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- CN113874971A CN113874971A CN202080038627.XA CN202080038627A CN113874971A CN 113874971 A CN113874971 A CN 113874971A CN 202080038627 A CN202080038627 A CN 202080038627A CN 113874971 A CN113874971 A CN 113874971A
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- aluminum
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- porous layer
- aluminized
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- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 385
- 238000004519 manufacturing process Methods 0.000 title claims description 124
- 239000003990 capacitor Substances 0.000 title claims description 74
- 239000000126 substance Substances 0.000 claims abstract description 204
- 239000000843 powder Substances 0.000 claims abstract description 73
- 229910000838 Al alloy Inorganic materials 0.000 claims abstract description 29
- 230000015572 biosynthetic process Effects 0.000 claims description 219
- 238000007743 anodising Methods 0.000 claims description 169
- 238000000034 method Methods 0.000 claims description 159
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- 230000036571 hydration Effects 0.000 claims description 58
- 238000006703 hydration reaction Methods 0.000 claims description 58
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- 239000001741 Ammonium adipate Substances 0.000 description 2
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- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
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- 235000019293 ammonium adipate Nutrition 0.000 description 2
- AMKPEQFFXVSTGY-UHFFFAOYSA-N azane boric acid octahydrate Chemical compound OB(O)O.OB(O)O.OB(O)O.OB(O)O.OB(O)O.N.N.N.N.N.N.N.N.N.N.N.N.N.N.N.O.O.O.O.O.O.O.O AMKPEQFFXVSTGY-UHFFFAOYSA-N 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
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- 239000008151 electrolyte solution Substances 0.000 description 2
- 238000004049 embossing Methods 0.000 description 2
- 229910052733 gallium Inorganic materials 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- CXMXRPHRNRROMY-UHFFFAOYSA-N sebacic acid Chemical compound OC(=O)CCCCCCCCC(O)=O CXMXRPHRNRROMY-UHFFFAOYSA-N 0.000 description 2
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- 229910052720 vanadium Inorganic materials 0.000 description 2
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 239000001361 adipic acid Substances 0.000 description 1
- 235000011037 adipic acid Nutrition 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 239000005030 aluminium foil Substances 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 238000005269 aluminizing Methods 0.000 description 1
- 239000008280 blood Substances 0.000 description 1
- 210000004369 blood Anatomy 0.000 description 1
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- 239000000470 constituent Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
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- QYHFIVBSNOWOCQ-UHFFFAOYSA-N selenic acid Chemical compound O[Se](O)(=O)=O QYHFIVBSNOWOCQ-UHFFFAOYSA-N 0.000 description 1
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- 230000003746 surface roughness Effects 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/04—Electrodes or formation of dielectric layers thereon
- H01G9/042—Electrodes or formation of dielectric layers thereon characterised by the material
- H01G9/045—Electrodes or formation of dielectric layers thereon characterised by the material based on aluminium
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
- C25D11/12—Anodising more than once, e.g. in different baths
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
- C25D11/16—Pretreatment, e.g. desmutting
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/04—Electrodes or formation of dielectric layers thereon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/04—Electrodes or formation of dielectric layers thereon
- H01G9/048—Electrodes or formation of dielectric layers thereon characterised by their structure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/04—Electrodes or formation of dielectric layers thereon
- H01G9/048—Electrodes or formation of dielectric layers thereon characterised by their structure
- H01G9/052—Sintered electrodes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention provides an aluminized foil (1) comprising: an aluminum foil (10) in which a first porous layer (3) comprising a sintered body of a powder (11) comprising aluminum or an aluminum alloy is laminated on a first surface (2a) of both surfaces of a foil-shaped base layer (2) comprising aluminum or an aluminum alloy; and a first chemical film (5) formed on the first porous layer (3). A plurality of cracks (7) extending in the Y direction with a length of 300 [ mu ] m or more are provided on the surface of the first porous layer (3) at intervals of 30 [ mu ] m to 150 [ mu ] m in the X direction.
Description
Technical Field
The present invention relates to an aluminized foil obtained by chemically converting an aluminum foil having a porous layer containing a sintered body of an aluminum or aluminum alloy powder, an electrode for an aluminum electrolytic capacitor, and a method for producing the aluminized foil.
Background
As an electrode for an aluminum electrolytic capacitor, an aluminum foil formed by anodizing an aluminum foil having a porous layer of a sintered body of aluminum-containing powder is known. In such a chemical aluminum foil, if the aluminum foil is bent in the anodizing step of anodizing the aluminum foil to form a chemical conversion coating, there is a problem that the aluminum foil is broken. In patent document 1, the surface of the sintered body is subjected to embossing processing so that the surface roughness of the sintered body falls within a predetermined value range, and then an anodic oxidation process is performed, thereby reducing the breakage of the aluminum foil.
Documents of the prior art
Patent document
Patent document 1: international publication No. 2016/136804
Disclosure of Invention
Technical problem to be solved by the invention
The reason why the bending strength of the aluminum foil is reduced in the anodizing step is because it is difficult to release stress from the aluminum foil as the chemical conversion coating grows. That is, in the anodic oxidation step, a chemical conversion coating grows on the surface of the porous layer of the sintered body containing the powder. Thereby, adjacent powders are bonded by the chemical film. In such a state, when the aluminum foil is bent, the powder is strongly bonded to each other, and thus stress due to deformation cannot be released from the aluminum foil. As a result, the bonding between the powders is locally broken. And, the crack is propagated, breaking the aluminum foil.
Here, even when anodic oxidation is performed on the aluminum foil on which the surface of the porous layer is subjected to embossing, adjacent powders are bonded by the chemical conversion coating as the chemical conversion coating grows. Therefore, even when the technique of patent document 1 is employed, stress caused by deformation is not easily released from the aluminum foil, and it is difficult to sufficiently suppress a decrease in the bending strength of the aluminum foil.
In view of the above problems, an object of the present invention is to provide an aluminized foil that can prevent or suppress cracking of an aluminum foil due to bending when anodizing the aluminum foil having a porous layer containing a sintered body of a powder. Also provided is a method for producing the aluminized foil.
Technical solution for solving technical problem
In order to solve the above-described problems, an aluminized foil according to the present invention includes: an aluminum foil in which a first porous layer containing a sintered body of a powder of aluminum or an aluminum alloy is laminated on a first surface of both surfaces of a foil-shaped base layer containing aluminum or an aluminum alloy; and a first chemical film formed on the first porous layer, wherein a plurality of cracks extending in a first direction at a length of 300 [ mu ] m or more in an in-plane direction are provided at intervals of 30 [ mu ] m to 150 [ mu ] m in a second direction orthogonal to the first direction in the in-plane direction on a surface of the first porous layer.
The aluminized foil of the present invention has a crack extending in a first direction of an in-plane direction with a length of 300 μm or more on a surface of the first porous layer. A plurality of cracks are provided at intervals of 30 to 150 [ mu ] m in a second direction of the in-plane direction of the aluminized foil. In the case of the aluminized foil having a plurality of cracks, even when the aluminum foil is bent by anodizing the aluminum foil and the adjacent powder is bonded to the aluminum foil by the first chemical film, the stress caused by the deformation can be released from the portion of the crack after the anodizing is completed. This prevents or suppresses local cracking of the bonds between the powders, and thus prevents or suppresses the crack from spreading and breaking the aluminum foil.
In the present invention, it is preferable that each of the plurality of cracks reaches a boundary between the base layer and the first porous layer. With this arrangement, even when the aluminum foil is bent during anodization, stress caused by deformation can be easily released from the aluminum foil.
In the present invention, the dimension of the aluminum foil in the second direction may be longer than the dimension in the first direction.
In the present invention, the thickness of the first porous layer may be 10 μm or more and 500 μm or less.
In the present invention, the average particle diameter of the powder may be 1 μm or more and 20 μm or less.
In the present invention, the thickness of the underlayer may be 10 μm or more and 100 μm or less.
In the present invention, a second porous layer including a sintered body of a powder containing aluminum or an aluminum alloy may be laminated on a second surface of the base layer opposite to the first surface, a second oxide film may be formed on the second porous layer, and a plurality of cracks extending in the in-plane direction of the second porous layer may be provided on the surface of the second porous layer at the intervals. With this arrangement, even when the aluminum foil has porous layers on both surfaces of the base layer, the stress generated in the anodized aluminum foil can be released.
Here, the present invention may be an electrode for an aluminum electrolytic capacitor including the above-described aluminum formed foil.
The electrode for an aluminum electrolytic capacitor of the present invention has a plurality of cracks in the first porous layer. Therefore, when an aluminum foil is anodized to produce an electrode for an aluminum electrolytic capacitor, even if the aluminum foil is bent, the aluminum foil can be prevented or suppressed from breaking. Further, since the electrode for an aluminum electrolytic capacitor has a plurality of cracks in the first porous layer, the specific surface area is increased as compared with the case where no cracks are present. Therefore, the electrostatic capacity of the electrode for an aluminum electrolytic capacitor can be increased as compared with the case where the first porous layer does not have a plurality of cracks.
In the present invention, the aluminized foil may have a roll shape wound in a spiral curve in the second direction. When the roll-shaped electrode for an aluminum electrolytic capacitor is formed by winding the aluminum foil, the roll-shaped electrode is easily wound in the second direction in which a plurality of cracks are aligned. Therefore, the aluminized foil having the crack can be wound in a shape close to a perfect circle, as compared with the case where the aluminized foil does not have the crack. That is, the aluminized foil can be formed into a roll shape wound in the second direction and has no bent portion in the middle. Here, if the roll-shaped electrode for an aluminum electrolytic capacitor, in which the aluminum foil is wound in a spiral curve shape, is used as the capacitor element, the electrode for an aluminum electrolytic capacitor having a longer dimension in the second direction can be accommodated when the capacitor element is accommodated in the outer case, as compared with a case where the electrode for an aluminum electrolytic capacitor is not wound in a spiral curve shape. This increases the surface area of the electrode for the aluminum electrolytic capacitor, and thus can increase the capacitance of the aluminum electrolytic capacitor. Further, by winding the aluminized foil in a spiral curve shape to form a roll shape, it is possible to prevent the aluminized foil from breaking at a bent portion, as compared with a case where the aluminized foil has a bent portion in the middle. Therefore, the wrappability of the aluminized foil can be improved.
Next, another aspect of the present invention provides an aluminized foil comprising: an aluminum foil in which a first porous layer containing a sintered body of a powder of aluminum or an aluminum alloy is laminated on a first surface of both surfaces of a foil-shaped base layer containing aluminum or an aluminum alloy; and a first chemical film formed on the first porous layer, wherein a plurality of cracks extending in a first direction of an in-plane direction are provided on a surface of the first porous layer so as to be separated in the in-plane direction and in a second direction orthogonal to the first direction, and each of the plurality of cracks reaches a boundary between the base layer and the first porous layer.
The aluminized foil of the present invention is provided with a plurality of cracks extending in a first direction of the in-plane directions on a surface of the first porous layer, the cracks being separated in a second direction of the in-plane directions. Each crack reaches the boundary between the base layer and the first porous layer. In the case of the aluminized foil having such a plurality of cracks, even if the aluminum foil is bent by anodizing the aluminum foil and the adjacent powder is bonded to the aluminum foil by the first chemical film, the stress due to the deformation can be released from the portion of the crack after the anodizing is completed. This prevents or suppresses local cracking of the bonds between the powders, and thus prevents or suppresses the crack from spreading and breaking the aluminum foil.
Here, the present invention may be an electrode for an aluminum electrolytic capacitor including the above-described aluminum formed foil.
The electrode for an aluminum electrolytic capacitor of the present invention has a plurality of cracks in the first porous layer. Therefore, when an aluminum foil is anodized to produce an electrode for an aluminum electrolytic capacitor, even if the aluminum foil is bent, the aluminum foil can be prevented or suppressed from breaking. Further, since the electrode for an aluminum electrolytic capacitor has a plurality of cracks in the first porous layer, the specific surface area is increased as compared with the case where no cracks are present. Therefore, the electrostatic capacity of the electrode for an aluminum electrolytic capacitor can be increased as compared with the case where the first porous layer does not have a plurality of cracks.
In the present invention, the aluminized foil may have a roll shape wound in a spiral curve in the second direction. When the roll-shaped electrode for an aluminum electrolytic capacitor is formed by winding the aluminum foil, the roll-shaped electrode is easily wound in the second direction in which a plurality of cracks are aligned. Therefore, the aluminized foil having the crack can be wound in a shape close to a perfect circle, as compared with the case where the aluminized foil does not have the crack. That is, the aluminized foil having a plurality of cracks can be formed into a roll shape wound in the second direction and has no bent portion in the middle. Here, if the roll-shaped electrode for an aluminum electrolytic capacitor, in which the aluminum foil is wound in a spiral curve shape, is used as the capacitor element, the electrode for an aluminum electrolytic capacitor having a longer dimension in the second direction can be accommodated when the capacitor element is accommodated in the outer case, as compared with a case where the electrode for an aluminum electrolytic capacitor is not wound in a spiral curve shape. This increases the surface area of the electrode for the aluminum electrolytic capacitor, and thus can increase the capacitance of the aluminum electrolytic capacitor. Further, by winding the aluminized foil in a spiral curve to form a roll shape, it is possible to prevent the aluminized foil from breaking at a bent portion, as compared with a case where the aluminized foil has a bent portion in the middle. Therefore, the wrappability of the aluminized foil can be improved.
Next, a method for manufacturing an aluminized foil according to the present invention is characterized in that: the method comprises a formation step of forming a first formation film on an aluminum foil, wherein the aluminum foil has a first porous layer formed by laminating a sintered body of powder of aluminum or aluminum alloy on a first surface of both surfaces of a foil-shaped base layer of aluminum or aluminum alloy, wherein the formation step comprises an anodizing step of anodizing the aluminum foil, wherein a crack formation treatment is performed in the formation step, wherein the crack formation treatment is performed so as to generate stress in the aluminum foil, a plurality of cracks extending in a first direction are provided separately in a second direction orthogonal to the first direction on a surface of the first porous layer, and wherein a post-crack formation anodizing treatment is performed in the anodizing step, and wherein the post-crack formation anodizing treatment is a treatment of anodizing the aluminum foil after the crack formation treatment.
According to the present invention, the aluminum foil is stressed in the chemical conversion step, whereby a plurality of cracks extending in the first direction are provided separately in the second direction on the surface of the first porous layer. After the cracks are formed, the aluminum foil is anodized. Here, by forming a crack in the first porous layer in the middle of the chemical conversion step, even if the first chemical coating grows by anodic oxidation thereafter, the closing of the crack by the first chemical coating can be suppressed. Therefore, an aluminized foil having a plurality of cracks can be obtained. Therefore, even when the adjacent powder is bent by the aluminum foil to which the first chemical film is bonded as the first chemical film grows, the stress caused by the deformation can be released from the crack. This prevents or suppresses local cracking of the bonds between the powders, and thus prevents or suppresses local crack propagation and fracture of the aluminum foil. Further, since the aluminum foil is anodized after the cracks are formed, the first chemical coating film can be formed on the first porous layer after the cracks are formed. Thus, the aluminum fresh surface (the surface of the bare metal aluminum) exposed to the surface of the first porous layer due to the formation of the crack can be coated with the reformed first chemical coating. Therefore, the leakage current of the aluminum foil or the electrode for the aluminum electrolytic capacitor in the anodic oxidation due to the crack can be reduced, and the breakage can be prevented or suppressed.
In the present invention, in the crack formation treatment, a plurality of the cracks extending in the first direction at a length of 300 μm or more may be provided at intervals of 30 μm to 150 μm in the second direction. By providing such a crack, even in the case where the first chemical film grows due to anodic oxidation, the closing of the crack by the first chemical film can be prevented or suppressed.
In the present invention, it is preferable that each crack reaches a boundary between the base layer and the first porous layer in the crack formation treatment. With such an arrangement, even if the aluminum foil is bent during the anodization due to the deep cracks, the stress generated by the deformation is easily released from the cracks.
The thickness of the first chemical film grown until the voltage at the time of anodization reaches a predetermined anodization voltage can be estimated. Therefore, if the pre-crack formation anodizing treatment is performed before the crack formation treatment, in which the aluminum foil is anodized until a predetermined anodizing voltage is reached, it is possible to avoid that the first chemical conversion coating becomes too thick at the time point of the crack formation treatment and the aluminum foil becomes too hard. This can prevent the aluminum foil from breaking when the aluminum foil is stressed. In addition, when the aluminum foil is stressed, a plurality of cracks can be uniformly formed on the surface of the first porous layer. Here, if a plurality of cracks are uniformly formed on the surface of the first porous layer, even if the thickness of the first chemical film increases to reach the target film withstand voltage, it is possible to suppress a decrease in the bending strength.
The predetermined anodization voltage may be 400V or less. The term "until the predetermined anodization voltage is reached" includes a time point when the predetermined anodization voltage is reached. With this arrangement, the first chemical film does not become too thick at the time of forming the crack, and the aluminum foil does not become too hard, as compared with the case where the crack forming treatment is performed after the voltage at the time of anodizing reaches the predetermined anodizing voltage. Therefore, when stress is generated in the aluminum foil, the aluminum foil is not easily broken. Further, if the crack formation treatment is performed until the voltage at the time of anodization reaches a predetermined anodization voltage, the first chemical film does not become too thick and the aluminum foil does not become too hard, so that stress is generated in the aluminum foil, whereby a plurality of cracks can be uniformly formed on the surface of the first porous layer. Here, if a plurality of cracks can be uniformly formed on the surface of the first porous layer, even if the first chemical film is formed thick by anodization after the voltage at the time of anodization reaches a predetermined anodization voltage, a decrease in the bending strength can be suppressed.
In the present invention, in the crack formation process, the first crack formation roll extending in the first direction may be brought into contact with a second surface of the aluminum foil opposite to the first surface, and the aluminum foil and the first crack formation roll may be moved relative to each other in the second direction. With this arrangement, the first crack-forming roller can stress the aluminum foil, thereby forming cracks in the first porous layer.
In the present invention, in the forming step, the aluminum foil may be caused to travel in the second direction by a plurality of rollers arranged along the second direction, and a roller having a smaller diameter than the other rollers among the plurality of rollers may be arranged as the first crack-forming roller. By using a small-diameter roller as the first crack-forming roller, stress is easily generated in the aluminum foil by the first crack-forming roller.
In the present invention, a second porous layer including a sintered body of aluminum or aluminum alloy powder is laminated on a second surface of the base layer opposite to the first surface in the aluminum foil, a second chemical coating film is formed on the second porous layer in the chemical conversion step, and in the crack formation treatment, a second crack formation roller extending in the first direction is brought into contact with the first surface at a position different from that of the first crack formation roller in the second direction, and the aluminum foil and the second crack formation roller are moved relative to each other in the second direction. With this arrangement, the aluminum foil can be stressed by the second crack-forming roller, and a plurality of cracks can be formed in the second porous layer. Therefore, even when the aluminum foil has porous layers on both surfaces of the base layer or when the aluminum foil is bent at the time of anodizing, the stress caused by the deformation can be released from the aluminum foil. Therefore, the aluminum foil can be prevented or suppressed from breaking.
In the present invention, the formation step may include a hydration step of forming a hydrated film on the aluminum foil before the anodic oxidation step, and in the anodic oxidation step, the aluminum foil on which the hydrated film is formed may be anodized, and the crack formation treatment may be performed in the middle of the hydration step. With this arrangement, in the hydration step, a hydrated film is formed on the surface of the first porous layer. Further, a crack is formed in the first porous layer in the middle of the hydration step. Thus, the crack formation process exposes the newly grown aluminum surface to the surface of the first porous layer due to the crack. That is, at the fracture surface of the first porous layer formed by the cracks, powder having no hydrated film formed on the surface thereof is exposed. Thereafter, in a hydration step which is continued after the crack formation treatment, a hydrated film is formed on the newly grown aluminum surface. Here, the hydrated film covering the fresh aluminum surface prevents or inhibits the powder bodies on both sides with the crack therebetween from being bonded to each other by the first chemical film in the anodizing process. Therefore, if the crack formation treatment is performed in the middle of the hydration step, the first chemical coating can be prevented or suppressed from closing the crack due to the first chemical coating when the first chemical coating grows in the crack formation treatment and the anodic oxidation step performed after the hydration step.
In the present invention, the formation step may include a hydration step of forming a hydrated film on the aluminum foil before the anodic oxidation step, and in the anodic oxidation step, the aluminum foil on which the hydrated film is formed may be anodized, and the crack formation treatment may be performed after the hydration step. With this arrangement, in the hydration step, a hydrated film is formed on the surface of the first porous layer. Here, the hydrated film serves as an obstacle to bonding of the powder bodies to each other via the first chemical film in the anodic oxidation step, and hinders or suppresses bonding of the powder bodies to each other. Therefore, by providing the crack formation treatment after the hydration step performed in the middle of the formation step, it is easy to suppress the phenomenon in which the cracks formed in the first porous layer are closed by the first formation film.
In the present invention, it is desirable to include a rehydration treatment in which a hydrated film is formed on the aluminum foil after the above-described crack formation treatment. With this arrangement, in the rehydration treatment performed after the crack formation treatment, a hydrated film is formed on the aluminum fresh surface exposed to the surface of the first porous layer due to the formation of cracks. Here, the hydrated film covering the fresh aluminum surface prevents or suppresses the powder bodies on both sides with the crack therebetween from being bonded to each other by the first chemical film in the anodizing step. Therefore, by performing the rehydration treatment after the crack formation treatment, the closing of the crack by the first chemical film can be suppressed when the first chemical film grows thereafter.
ADVANTAGEOUS EFFECTS OF INVENTION
The aluminized foil of the present invention has a crack extending in a first direction of an in-plane direction with a length of 300 μm or more on a surface of the first porous layer. A plurality of cracks are provided at intervals of 30 to 150 [ mu ] m in a second direction of the in-plane direction of the aluminized foil. In the case of the aluminized foil having such a plurality of cracks, even when the aluminum foil is bent when the aluminum foil is anodized, the stress generated by the deformation can be released from the portion of the crack after the anodization is completed. This prevents or suppresses local cracking of the bonds between the powders, and thus prevents or suppresses cracking of the aluminum foil.
In another aspect of the present invention, a plurality of cracks extending in a first direction of in-plane directions are provided on a surface of the first porous layer so as to be separated in a second direction of the in-plane directions. Each crack reaches the boundary between the base layer and the first porous layer. In the case of the aluminized foil having such a plurality of cracks, even when the aluminum foil is bent when the aluminum foil is anodized, the stress generated by the deformation can be released from the portion of the crack after the anodization is completed. This prevents or suppresses local cracking of the bonds between the powders, and thus prevents or suppresses cracking of the aluminum foil.
The method for producing an aluminized foil according to the present invention includes a chemical conversion step of forming a first chemical conversion coating on an aluminum foil having a first porous layer laminated thereon, and the chemical conversion step includes an anodic oxidation step of anodizing the aluminum foil. In the chemical conversion step, cracks are formed in the first porous layer, and in the anodic oxidation step, the aluminum foil is anodized after the cracks are formed. In this way, by forming cracks in the first porous layer in the middle of the formation step, an aluminized foil having a plurality of cracks can be obtained. Therefore, the stress of the aluminum foil due to deformation can be released from the crack. This prevents or suppresses local cracking of the bonds between the powders, and thus prevents or suppresses local crack propagation and fracture of the aluminum foil. Further, by the anodic oxidation treatment after the formation of the cracks, the first chemical coating can be formed again on the first porous layer after the generation of the cracks. Thus, the surface of the metallic aluminum exposed by the formation of the crack can be coated with the reformed chemical film. Therefore, the leakage current of the aluminum foil or the electrode for the aluminum electrolytic capacitor in the anodic oxidation due to the crack can be reduced, and the breakage can be prevented or suppressed.
Drawings
Fig. 1 is a photograph of the surface of an aluminized foil taken at an enlarged scale by a scanning electron microscope.
Fig. 2 is a photograph of a cross section of an aluminized foil cut along the longitudinal direction, taken under magnification by a scanning electron microscope.
Fig. 3 is an explanatory view of the aluminum formed foil.
Fig. 4 is an explanatory view of a measuring method for measuring the interval between cracks formed on the surface of the aluminized foil.
Fig. 5 is a schematic diagram of an electrode for a roll-shaped aluminum electrolytic capacitor.
Fig. 6 is an explanatory view of an aluminum foil serving as a base material for forming an aluminum foil.
Fig. 7 is a flow chart showing a first method of manufacturing an aluminised foil.
Fig. 8 is a flow chart showing a second method of manufacturing an aluminized foil.
Fig. 9 is a flow chart showing a third method of manufacturing an aluminized foil.
Fig. 10 is a flow chart showing a fourth method of manufacturing an aluminized foil.
Fig. 11 is a flowchart showing a fifth manufacturing method of the aluminized foil.
Fig. 12 is an explanatory view of the crack formation process.
FIG. 13 is a table showing the timing of performing the crack formation treatment in the method for producing an aluminized foil according to examples 1 to 5.
FIG. 14 is an explanatory view of the timing of performing the crack formation treatment in the method for producing an aluminized foil according to examples 1 to 5.
FIG. 15 is a table showing the interval between cracks, the bending strength, the tensile strength, the capacitance and the coating withstand voltage of the aluminized foil according to examples 1 to 5 and comparative examples 1 and 2.
Fig. 16 is a photograph of the surface of the aluminized foil produced by the production method of example 5 taken by a scanning electron microscope at an enlarged scale.
Fig. 17 is a photograph of the surface of the aluminized foil of comparative example 1 taken by scanning electron microscope with magnification.
Fig. 18 is a photograph of a cross section of the aluminized foil of comparative example 1 taken by scanning electron microscope.
FIG. 19 is a table showing the timing of performing the crack formation treatment in the method for producing an aluminized foil according to examples 6 to 8.
FIG. 20 is an explanatory view of the timing of performing the crack formation treatment in the method for producing an aluminized foil according to examples 6 to 8.
FIG. 21 is a table showing the interval between cracks, the bending strength, the tensile strength, the capacitance and the coating withstand voltage of the aluminized foil in examples 6 to 8.
FIG. 22 is a table showing the timing of performing the crack formation treatment in the method for producing an aluminized foil according to examples 9 to 11.
FIG. 23 is an explanatory view of the timing of performing the crack formation treatment in the method for producing an aluminized foil according to examples 9 to 11.
FIG. 24 is a table showing the interval between cracks, the bending strength, the tensile strength, the capacitance and the coating withstand voltage of the aluminized foil according to examples 9 to 11.
Fig. 25 is a flowchart showing a sixth manufacturing method of the aluminizing foil.
Fig. 26 is a flowchart showing a seventh manufacturing method of the aluminized foil.
Detailed Description
Embodiments of an aluminized foil and a method for producing an aluminized foil according to the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following embodiments. In addition, some or all of the constituent elements in the embodiments may be combined as appropriate. The aluminum foil of this example was used as an electrode for an aluminum electrolytic capacitor. An aluminum electrolytic capacitor having an aluminum foil as an electrode (anode foil) for an aluminum electrolytic capacitor will be described below, followed by an explanation of the aluminum foil and a method for producing the aluminum foil. In the present specification, when a numerical range is represented by a lower limit value and an upper limit value using the symbols "to" include both the lower limit value and the upper limit value.
(aluminum electrolytic capacitor)
In order to manufacture an aluminum electrolytic capacitor using an aluminized foil, an anode foil and a cathode foil made of an aluminized foil (electrode for an aluminum electrolytic capacitor) are laminated via a separator, and wound to form a capacitor element. Next, the capacitor element is impregnated with an electrolyte (paste). Then, the capacitor element containing the electrolytic solution is housed in an outer case, and the case is sealed with a sealing member.
In the case of using a solid electrolyte instead of the electrolytic solution, a solid electrolyte layer is formed on the surface of an anode foil made of an aluminized foil (electrode for an aluminum electrolytic capacitor), and then a cathode layer is formed on the surface of the solid electrolyte layer, followed by being externally coated with a resin or the like. At this time, an anode terminal electrically connected to the anode and a cathode terminal electrically connected to the cathode layer are provided. In this case, a plurality of anode foils may be stacked.
(aluminum formed foil)
FIG. 1 is a photograph of an aluminized foil surface of the present invention taken by a scanning electron microscope at an enlarged scale. Fig. 2 is a photograph of a cross section of the aluminized foil of fig. 1 cut along the longitudinal direction, taken under magnification by a scanning electron microscope. Fig. 3 is an explanatory diagram showing the relationship between the powder constituting the porous layer and the chemical conversion coating in the aluminized foil. Fig. 3 schematically shows a base layer, powder, and a chemical conversion coating film constituting an aluminum chemical conversion foil. Fig. 4 is an explanatory view of a measuring method for measuring the interval between cracks formed on the surface of the aluminized foil.
The aluminum foil 1 is produced by anodizing an aluminum foil including the base layer 2 and the porous layers (the first porous layer 3 and the second porous layer 4). The aluminized foil 1 (electrode for an aluminum electrolytic capacitor) is long.
As shown in fig. 2, the aluminized foil 1 has: a foil-shaped base layer 2 containing aluminum or an aluminum alloy, and a first porous layer 3 laminated on a first surface 2a of the base layer 2; and a second porous layer 4 laminated on a second surface 2b of the base layer 2 opposite to the first surface 2 a. Each of first porous layer 3 and second porous layer 4 contains a sintered body of a powder of aluminum or an aluminum alloy. The aluminized foil 1 has a first chemical film 5 formed on the first porous layer 3 and a second chemical film 6 formed on the second porous layer 4.
In the following description, 3 directions orthogonal to each other are defined as an X direction, a Y direction, and a Z direction, and the X direction is defined as a longitudinal direction of the aluminized foil 1. The Y direction is defined as the short side direction of the aluminized foil 1. The Z direction is a direction in which first porous layer 3 and second porous layer 4 are laminated with respect to base layer 2.
In this example, the base layer 2 is a foil made of pure aluminum. As the base layer 2, a foil made of an aluminum alloy can be used. The aluminum alloy is obtained by adding at least 1 metal element selected from silicon, iron, copper, manganese, magnesium, chromium, zinc, titanium, vanadium, gallium, nickel, and boron to aluminum, or aluminum containing any of these elements as an inevitable impurity element. The thickness dimension T1 of the base layer 2 is generally 10 μm or more, preferably 20 μm or more, and is generally 100 μm or less, preferably 50 μm or less.
First porous layer 3 and second porous layer 4 are sintered bodies of powders containing at least 1 kind selected from aluminum and aluminum alloys. As shown in fig. 3, first porous layer 3 and second porous layer 4 have a three-dimensional mesh structure in which the powder maintains a void and is sintered and connected to each other. The first and second chemical conversion coatings 5 and 6 are formed on the surface of the three-dimensional mesh structure of the powder 11. Here, first porous layer 3 and second porous layer 4 have a three-dimensional mesh structure, and therefore have large surface areas. Therefore, when using the aluminum foil 1 as an electrode for an aluminum electrolytic capacitor, a capacitor having a large capacitance can be manufactured.
The purity of aluminum in the aluminum powder 11 is 99.80 mass% or more. The aluminum alloy used as the powder 11 contains 1 or more kinds selected from silicon, iron, copper, manganese, magnesium, chromium, zinc, titanium, vanadium, gallium, nickel, boron, zirconium, and the like in aluminum. The content of these elements in the aluminum alloy is desirably 100 mass ppm or less, particularly 50 mass ppm or less.
The thickness of the first porous layer 3 and the thickness of the second porous layer 4 are typically the same or approximately the same. However, the thickness of first porous layer 3 may be different from the thickness of second porous layer 4. In this case, the thickness of first porous layer 3 may be made larger than the thickness of second porous layer 4, or the thickness of second porous layer 4 may be made larger than the thickness of first porous layer 3. In this example, thickness T2 of first porous layer 3 and thickness T3 of second porous layer 4 are each 10 μm to 500m inclusive. In addition, thickness T2 of first porous layer 3 and thickness T3 of second porous layer 4 are preferably 50 μm to 200 μm inclusive. That is, the thickness of the porous layer obtained by summing the thickness of first porous layer 3 and the thickness of second porous layer 4 is 20 μm or more and 1000 μm or less. The thickness of the porous layer obtained by summing the thickness of first porous layer 3 and the thickness of second porous layer 4 is preferably 100 μm or more and 400 μm. The average particle diameter K of powder 11 constituting first porous layer 3 and second porous layer 4 is 1 μm or more and 20 μm or less.
The average particle diameter K of powder 11 is obtained by observing the cross section of first porous layer 3 or second porous layer 4 with a scanning electron microscope. Specifically, the sintered powder 11 is observed in a state in which a part of the powder is melted or the powder 11 is connected to each other, but a part having a roundish shape can be regarded as a particle approximately. Therefore, in the cross-sectional view, the maximum diameter of each of the particles having a substantially circular shape is defined as the particle diameter of the particle, and the particle diameters of about 50 particles are measured, and the average of these is defined as the average particle diameter K of the powder 11 after sintering.
As shown in fig. 1, on the surface of first porous layer 3, a plurality of cracks 7 extending in the Y direction (first direction) at a length of 300 μm or more in the in-plane direction are provided at intervals of 30 μm to 150 μm in the X direction (second direction) in the in-plane direction. As shown in fig. 2, each crack 7 provided in first porous layer 3 reaches the boundary between base layer 2 and first porous layer 3. Similarly, a plurality of cracks 7 extending in the Y direction at a length of 300 μm or more are provided on the surface of the second porous layer 4 at intervals of 30 to 150 μm in the X direction orthogonal to the Y direction. Each crack 7 provided in second porous layer 4 reaches the boundary between base layer 2 and second porous layer 4.
The length and the interval of each crack 7 included in first porous layer 3 and second porous layer 4 were measured by observation with a scanning electron microscope. More specifically, as shown in fig. 4, when observed in a field of view in a range of 500 μm or more in the X direction and 1000 μm or more in the Y direction of the aluminized foil 1, a reference line 8 is drawn in the X direction near the center of the field of view. Then, the number of intersections 9 with the cracks 7 having a length of 300 μm or more was counted. Then, the length of the reference line 8 converted from a scale is divided by the number of intersections 9, and the interval of the cracks 7 having a length of 300 μm or more is calculated. The interval between adjacent cracks 7 was determined as the average of the measurement and the calculation performed in 3 fields or more.
(Effect of aluminum conversion into foil)
In the aluminized foil 1 of the present example, the cracks 7 extending in the Y direction with a length of 300 μm or more are formed on the surfaces of the porous layers (the first porous layer 3 and the second porous layer 4). The plurality of cracks 7 are provided at intervals of 30 to 150 μm in the X direction of the aluminized foil 1. In the case of the aluminized foil 1 having the plurality of cracks 7, even when the aluminum foil in which the adjacent powders 11 are bonded by the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating) is bent by the anodic oxidation, the stress due to the deformation can be released from the portion of the crack 7 after the anodic oxidation is completed. This can prevent or suppress the occurrence of local cracks in the bonds between the powders 11, and thus can prevent or suppress the propagation of such cracks and the breakage of the aluminum foil.
Further, each of the plurality of cracks 7 reaches the boundary between the base layer 2 and the porous layer (the first porous layer 3 and the second porous layer 4). Therefore, the stress due to the deformation can be easily released from the aluminum foil.
Here, when the aluminum foil 1 is used as an electrode for an aluminum electrolytic capacitor, the electrode for an aluminum electrolytic capacitor has a plurality of cracks 7 in the porous layers (the first porous layer 3 and the second porous layer 4). Therefore, the specific surface area of the electrode for an aluminum electrolytic capacitor is larger than that in the case where the porous layers (first porous layer 3 and second porous layer 4) do not have cracks 7. Therefore, if the aluminum foil is used as an electrode for an aluminum electrolytic capacitor, the capacitance can be increased.
In addition, when the roll-shaped electrode for an aluminum electrolytic capacitor is formed by winding the aluminum foil 1, the roll-shaped electrode is easily wound in the X direction in which the plurality of cracks 7 are aligned. Therefore, the aluminized foil 1 having the crack 7 can be wound in a shape close to a perfect circle, as compared with the case where the aluminized foil does not have the crack 7.
Fig. 5 is a schematic view of an electrode for an aluminum electrolytic capacitor in which the formed aluminum foil 1 is wound in a spiral curve in a second direction, and shows a side view of the formed aluminum foil 1 as viewed from the first direction. In fig. 5, an aluminized foil 1 is wound around an outer peripheral surface of a roller 16 having a diameter of 1mm to form a roll shape. Even when wound around the roll 16 in this manner, the aluminized foil 1 (electrode 15 for an aluminum electrolytic capacitor) can be wound in a shape close to a perfect circle without being bent in the middle. That is, when the aluminized foil having no crack 7 is wound, a plurality of bent portions are formed in the middle of the aluminized foil. On the other hand, when the aluminized foil 1 having the plurality of cracks 7 is wound, the roll shape can be formed so as to be wound in the X direction without a bent portion in the middle.
Here, if the roll-shaped aluminum electrolytic capacitor electrode 15 formed by winding the aluminum foil 1 in a nearly perfect circle shape is used as the capacitor element, the aluminum electrolytic capacitor electrode 15 having a longer dimension in the X direction can be accommodated when the capacitor element is accommodated in the outer case, as compared with a case where the aluminum electrolytic capacitor electrode is not wound in a nearly perfect circle shape. This increases the surface area of the electrode 15 for the aluminum electrolytic capacitor, thereby increasing the capacitance of the aluminum electrolytic capacitor. Further, if the formed aluminum foil 1 is wound in a spiral curve shape to form a roll shape, the formed aluminum foil 1 can be prevented from being broken at a bent portion, as compared with a case where the formed aluminum foil 1 has a bent portion in the middle. Therefore, the wrappability of the aluminized foil 1 can be improved.
(method for producing aluminized chemical foil)
Fig. 6 is an explanatory view of an aluminum foil serving as a base material of the aluminized foil 1. In fig. 6, an aluminum foil is schematically shown. Fig. 7 is a flow chart showing a first manufacturing method of the aluminised foil 1. Fig. 8 is a flow chart showing a second manufacturing method of the aluminised foil 1. Fig. 9 is a flowchart showing a third manufacturing method of the aluminized foil 1. Fig. 10 is a flowchart showing a fourth manufacturing method of the aluminized foil 1. Fig. 11 is a flowchart showing a fifth manufacturing method of the aluminized foil 1.
Next, a method for manufacturing the aluminized foil 1 will be described with reference to fig. 6 to 11. As shown in fig. 6, aluminum foil 10 is used as a base material in the production of the aluminum formed foil 1. The aluminium foil 10 has a foil-like substrate layer 2 comprising aluminium or an aluminium alloy. A first porous layer 3 containing a sintered body of aluminum or aluminum alloy powder 11 is laminated on the first surface 2a of the base layer 2, and a second porous layer 4 containing a sintered body of aluminum or aluminum alloy powder 11 is laminated on the second surface 2b of the base layer 2. In this example, powder 11 of first porous layer 3 and powder 11 of second porous layer 4 are made of powder 11 of the same metal. In addition, the thickness of first porous layer 3 is the same as or substantially the same as the thickness of second porous layer 4.
As shown in fig. 7 to 11, the method for producing the aluminized foil 1 includes: a chemical conversion step ST1 of forming first chemical conversion coating 5 on first porous layer 3 of aluminum foil 10 (base material) and forming second chemical conversion coating 6 on second porous layer 4. The formation step ST1 includes in order: a hydration step ST2 of performing hydration treatment for forming a hydrated film on the aluminum foil 10; an anodizing step ST3 of anodizing the aluminum foil 10 having the hydrated film formed thereon. In this example, in the anodizing step ST3, heat treatment ST31 for exposing the defective portion by heating the aluminum foil 10 is performed in the middle of the constant voltage chemical conversion treatment step. That is, as shown in fig. 7 to 11, in the anodizing step ST3, anodizing treatment is performed before and after (not shown) the heat treatment ST 31. The same applies to other cases described with reference to the flowcharts in this specification.
In addition, in the formation step ST1, a crack formation process ST11 is performed in which stress is applied to the aluminum foil 10 and a plurality of cracks 7 extending in the Y direction are provided separately in the X direction on the surface of the first porous layer 3 and the surface of the second porous layer 4 in the crack formation process ST 11.
To describe the method of manufacturing the aluminized foil 1 of the present example in more detail, in the anodizing step ST3, the post-crack-formation anodizing treatment ST3A is performed in which the aluminum foil 10 is anodized after the crack-formation treatment ST 11. In the drawings and the following description, the post-crack-formation anodizing treatment ST3A is simply referred to as post-anodizing treatment ST 3A.
Here, in fig. 7 and 11, a crack formation process ST11 is performed in the middle of the chemical conversion process ST1 and in the middle of the hydration process ST 2. That is, in the hydration step ST2, hydration treatment (not shown) is performed before and after the crack formation treatment ST 11.
In fig. 9 and 10, a crack formation process ST11 is performed in the middle of the chemical conversion step ST1 and in the middle of the anodic oxidation step ST 3. That is, in the anodizing step ST3, before the crack formation process ST11, the pre-crack formation anodizing process ST3B is performed in which the aluminum foil 10 is anodized until the voltage at the time of anodizing reaches the predetermined anodizing voltage. In the drawings and the following description, the pre-crack-formation anodizing treatment ST3B is simply referred to as a pre-anodizing treatment ST 3B. That is, when the crack formation process ST11 is performed in the middle of the anodization step ST3, the pre-anodization process ST3B, the crack formation process ST11, and the post-anodization process ST3A are sequentially performed in the anodization step ST 3.
In the hydration step ST2, the aluminum foil 10 is boiled in a hydration treatment liquid having a liquid temperature of 80 ℃ or higher, and an aluminum hydration film such as boehmite is formed on the aluminum foil 10. As the hydration treatment liquid, pure water may be used. The rehydration process ST21 described later can be performed in the same manner.
In the anodizing step ST3, the aluminum foil 10 is immersed in the chemical conversion treatment liquid so that the voltage at the time of anodizing (voltage output from the power supply) reaches a predetermined anodizing voltage. Thereby, chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) are formed on the aluminum foil 10. As the chemical conversion treatment liquid, sulfuric acid or a salt thereof, selenic acid or a salt thereof, boric acid or a salt thereof, phosphoric acid or a salt thereof, an organic acid or a salt thereof (for example, adipic acid or a salt thereof, citric acid or a salt thereof, sebacic acid or a salt thereof, oxalic acid or a salt thereof, and the like), sodium hydroxide or a salt thereof, and the like can be used. The anodic oxidation voltage is set between 5V and 1000V. Of course, the anodization (post-anodization ST3A and pre-anodization ST3B) performed in the anodization step ST3 may be performed in the same manner.
In the heat treatment ST31 performed in the middle of the anodizing step ST3, the aluminum foil 10 is placed in, for example, a heat treatment furnace and heated. The temperature of the atmosphere in the heat treatment furnace is 300 ℃ to 600 ℃. The atmosphere in the heat treatment furnace may be any of an atmospheric atmosphere, an inert gas atmosphere, and a water vapor atmosphere.
In the method for producing the aluminized foil 1 of the present example, the crack formation process ST11 is performed in the middle of the hydration step ST2 before the formation of the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) or between the hydration step ST2 and the anodic oxidation step ST 3. At this time, in the anodizing process ST3 (post anodizing process ST3A) after the crack formation process ST11, the aluminum foil 10 after the crack formation is anodized.
Alternatively, in the method for manufacturing the aluminized foil 1 of this example, in the anodizing step ST3, crack formation processing ST11 is performed before the voltage at the time of anodizing reaches the final target anodizing voltage. At this time, since the crack formation process ST11 is performed in the middle of the anodizing process ST3, the pre-anodizing process ST3B and the post-anodizing process ST3A are performed before and after the crack is formed. In the post-anodizing treatment ST3A, the aluminum foil 10 is anodized to an anodizing voltage higher than the predetermined anodizing voltage reached in the pre-anodizing treatment ST 3B.
The predetermined anodization voltage is usually 400V or less. The predetermined anodization voltage is preferably 300V or less, and more preferably 250V or less. In this example, in the anodizing step ST3, the aluminum foil 10 is anodized until the anodizing voltage reaches the upper limit values, and thereafter, the crack formation treatment ST11 is performed. This makes it possible to generate stress in the aluminum foil 10 at a timing when the chemical conversion coating film is not excessively thick and the aluminum foil 10 is not excessively hard. As a result, when the aluminum foil 10 is stressed, the aluminum foil 10 is prevented from being broken, and a plurality of cracks are uniformly formed on the surface of the porous layer. Here, the crack formation process ST11 may be performed before the formation of the chemical conversion coating as long as it is in the chemical conversion step ST1, and therefore, the lower limit value of the predetermined anodization voltage is not particularly limited. Therefore, the lower limit of the predetermined anodization voltage is usually 0V or more. The lower limit of the predetermined anodization voltage is preferably 10V or more, and more preferably 50V or more. In the anodization step ST3, the final anodization voltage, which is the final target of the voltage at the time of anodization, may be set as appropriate according to the properties of the target aluminized foil 1. Therefore, the final anodization voltage is not particularly limited, and may be set to 1000V or less, for example.
In the anodization step ST3, the aluminum foil 10 may be anodized by other known methods.
Here, at the end of the anodizing step ST3 in the forming step ST1, the formed aluminum foil 10, i.e., the aluminized foil 1, is wound around a winding roll to form a roll.
Specific examples of the method for producing the aluminum foil 1 include the following first to fifth production methods that differ in timing of performing the crack formation process ST 11.
As shown in fig. 7, the first production method of the aluminized foil 1 performs a crack formation process ST11 in the middle of the hydration step ST 2. In the anodizing process ST3 performed after the hydration process ST2, post-anodizing process ST3A is performed.
As shown in fig. 8, the second manufacturing method of the aluminum formed foil 1 performs a crack forming process ST11 between the hydration process ST2 and the anodic oxidation process ST 3. In the anodizing step ST3 performed after the crack formation process ST11, a post-anodizing process ST3A is performed.
As shown in fig. 9, the third manufacturing method of the aluminum foil 1 performs a crack formation process ST11 in the middle of the anodizing step ST 3. Specifically, in the anodizing step ST3, the aluminum foil 10 is anodized to a pre-anodizing treatment ST3B in which a predetermined anodizing voltage is reached, the pre-anodizing treatment ST3B is followed by the crack formation treatment ST11, and the post-anodizing treatment ST3A is followed by the crack formation treatment ST 11.
In the fourth manufacturing method of aluminized foil 1, as shown in fig. 10, crack formation processing ST11 is performed in the middle of anodizing step ST3, in the same manner as in the third manufacturing method. Specifically, in the anodizing step ST3, the aluminum foil 10 is anodized to a pre-anodizing treatment ST3B in which a predetermined anodizing voltage is reached, and the crack forming treatment ST11 is performed after the pre-anodizing treatment ST 3B. Further, after the crack formation process ST11, a rehydration process ST21 of forming a hydrated film on the aluminum foil 10 is performed, and after the rehydration process ST21, a post-anodization process ST3A is performed. That is, in the fourth manufacturing method of aluminized foil 1, crack formation treatment ST11 and rehydration treatment ST21 are continuously performed in the middle of anodizing step ST 3.
As shown in fig. 11, the fifth manufacturing method of the aluminized foil 1 performs a crack formation process ST11 in the middle of the hydration step ST 2. Then, a crack formation process ST11 is performed in the middle of the anodization step ST 3. Specifically, in the hydration process ST2, the crack formation process ST11 is performed, and the hydration process is performed before and after the crack formation process ST 11. In the anodizing process ST3, a pre-anodizing treatment ST3B of anodizing the aluminum foil 10 until a predetermined anodizing voltage is reached is performed, a crack formation treatment ST11 and a rehydration treatment ST21 are continuously performed after the pre-anodizing treatment ST3B, and a post-anodizing treatment ST3A is performed after the rehydration treatment ST 21.
Next, a specific method of stressing the aluminum foil 10 in the crack formation process ST11 will be described. Fig. 12 is an explanatory diagram of the crack formation process ST 11. As shown in fig. 12, in the crack formation process ST11, the aluminum foil 10 is made to travel along a plurality of rollers 21 aligned in the X direction.
The respective rotation axes of the plurality of rollers 21 extend in the Y direction. Further, among the plurality of rollers 21 arranged in the X direction, a roller 21 having a smaller diameter than the other rollers 21 is arranged. Of these small diameter rollers 21, the roller 21 that contacts the second surface 2b of the aluminum foil 10 that is traveling is disposed as a first crack formation roller 21(1), and the first crack formation roller 21(1) is a roller that generates stress in the aluminum foil 10 and cracks 7 in the first porous layer 3. Of these small diameter rollers 21, the roller 21 that contacts the first surface 2a of the aluminum foil 10 that is traveling is disposed as a second crack formation roller 21(2), and the second crack formation roller 21(2) is a roller that generates stress in the aluminum foil 10 and cracks 7 in the second porous layer 4. The first crack-forming roller 21(1) and the second crack-forming roller 21(2) each have a diameter dimension M of 5mm to 60 mm. In this example, the first crack-forming roller 21(1) and the second crack-forming roller 21(2) have the same diameter dimension M, but the diameter dimensions M may be different.
In this example, the first crack formation roller 21(1) and the second crack formation roller 21(2) are made of metal. The first crack formation roller 21(1) and the second crack formation roller 21(2) are pressed by the pressing rollers 23, respectively. The surface of each pressing roller 23 is covered with an elastic member such as rubber. The diameter of each pressing roller 23 is desirably larger than the diameter of the first crack formation roller 21(1) and the diameter of the second crack formation roller 21 (2).
When the aluminum foil 10 travels between the first crack formation roller 21(1) and the pressing roller 23, stress is generated in the aluminum foil 10. As a result, a plurality of predetermined cracks 7 are formed in first porous layer 3. When the aluminum foil 10 travels between the second crack formation roller 21(2) and the pressing roller 23, stress is generated in the aluminum foil 10. Therefore, a plurality of predetermined cracks 7 are formed in second porous layer 4.
The wrap angle of the first crack forming roll 21(1) when the aluminum foil 10 travels between the first crack forming roll 21(1) and the pressing roll 23 is usually-180 ° to 180 °, preferably-45 ° to 45 °. The wrap angle of the second crack forming roll 21(2) when the aluminum foil 10 travels between the second crack forming roll 21(2) and the pressing roll 23 is usually-180 ° to 180 °, preferably-45 ° to 45 °. Further, the wrap angle of the first crack formation roller 21(1) and the second crack formation roller 21(2) is preferably 0 ° or more. Therefore, the wrap angle of the first crack forming roll 21(1) and the second crack forming roll 21(2) is 0 ° to 180 °, preferably 0 ° to 45 °. Here, when the first crack-forming roller 21(1) is brought into contact with the second surface 2b of the aluminum foil 10 by setting the wrap angle of the first crack-forming roller 21(1) to the above range, the desired cracks 7 are easily formed in the first porous layer 3. When the wrap angle of the second crack-forming roller 21(2) is set to the above range, the desired cracks 7 are easily formed in the second porous layer 4 when the second crack-forming roller 21(2) is brought into contact with the first surface 2a of the aluminum foil 10.
In addition, the plurality of rollers 21 may have a plurality of first crack formation rollers 21 (1). In the case where the plurality of first crack formation rollers 21(1) are provided, it is desirable that the plurality of rollers 21 have the same number of second crack formation rollers 21(2) as the first crack formation rollers 21 (1). At this time, the first crack-forming roller 21(1) and the second crack-forming roller 21(2) preferably contact the aluminum foil 10 at different positions.
(Effect)
In the method for producing the aluminized foil 1 of this example, the aluminum foil 10 is stressed in the formation step ST1, whereby a plurality of cracks 7 extending in the Y direction are provided on the surfaces of the porous layers (the first porous layer 3 and the second porous layer 4) so as to be separated in the X direction. Then, a post-anodization process ST3A is performed to anodize the aluminum foil 10 after the crack 7 is formed. Here, by forming the cracks 7 in the porous layers (the first porous layer 3 and the second porous layer 4) in the middle of the chemical conversion step ST1, even when the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) grow by the subsequent anodic oxidation, it is possible to suppress the phenomenon in which the cracks 7 are closed by the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6). Therefore, the aluminized foil 1 having the plurality of cracks 7 can be obtained. Therefore, even when the aluminum foil 10 in which the adjacent powders 11 are bonded by the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) is bent as the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) grow, the stress caused by the deformation can be released from the crack 7. This can prevent or suppress local cracking of the bonds between the powders 11, and thus can prevent or suppress local crack propagation and fracture of the aluminum foil 10. Further, since the aluminum foil 10 is anodized after the cracks 7 are formed, the chemical film (the first chemical film 5 and the second chemical film 6) can be formed on the porous layers (the first porous layer 3 and the second porous layer 4) after the cracks 7 are formed. Thus, the aluminum newly formed surfaces (the surfaces of the exposed metallic aluminum) exposed to the surfaces of the porous layers (the first porous layer 3 and the second porous layer 4) by the formation of the cracks 7 can be covered with the re-formed chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6). Therefore, the leakage current of the aluminum foil 10 or the electrode for an aluminum electrolytic capacitor in the anodization due to the crack 7 can be reduced, and the breakage can be prevented or suppressed.
In the chemical conversion step ST1, the thickness of the chemical conversion coating (the first chemical conversion coating 5 and the second chemical conversion coating 6) that grows until the voltage output from the power supply reaches the predetermined anodization voltage at the time of anodization can be estimated. Therefore, the thickness of the chemical conversion coating (the first chemical conversion coating 5 and the second chemical conversion coating 6) can be controlled according to the voltage output from the power supply at the time of anodizing. Therefore, if the pre-anodizing treatment ST3B is performed before the crack formation treatment ST11 in which the aluminum foil 10 is anodized until the voltage at the time of anodizing reaches the predetermined anodizing voltage, and then the crack formation treatment ST11 is performed, it is possible to avoid the phenomenon that the chemical conversion coating (the first chemical conversion coating 5 and the second chemical conversion coating 6) becomes too thick and the aluminum foil 10 becomes too hard at the time point of performing the crack formation treatment ST 11. Therefore, when stress is applied to the aluminum foil 10 in the crack formation process ST11, the aluminum foil 10 can be prevented from being broken.
In this example, since it is possible to avoid the aluminum foil 10 becoming too hard when the crack formation process ST11 is performed, the plurality of cracks 7 can be uniformly formed on the surfaces of the porous layers (the first porous layer 3 and the second porous layer 4) by stressing the aluminum foil 10. Here, if a plurality of cracks 7 are uniformly formed on the surface of the porous layer (first porous layer 3 and second porous layer 4), even if the thickness of the chemical conversion coating (first chemical conversion coating 5 and second chemical conversion coating 6) increases to reach the target coating withstand voltage, it is possible to suppress a decrease in the bending strength.
In the crack formation process ST11, a plurality of cracks 7 extending in the Y direction at a length of 300 μm or more are provided at intervals of 30 to 150 μm in the X direction. If such a crack 7 is provided, even when the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) grow due to anodic oxidation, closure of the crack 7 due to the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) can be prevented or suppressed.
In the crack formation process ST11, each crack 7 is made to reach the boundary between the base layer 2 and the porous layers (the first porous layer 3 and the second porous layer 4). Thus, even when the aluminum foil 10 is bent during the anodization, the stress caused by the deformation is easily released from the crack 7.
As shown in examples described later, the chemical conversion coating (the first chemical conversion coating 5 and the second chemical conversion coating 6) does not become excessively thick until the voltage at the time of anodizing (anodizing voltage) reaches 250V, and the hardness of the aluminum foil 10 is suitable for forming the crack 7. Therefore, in the formation step ST1, by performing the pre-crack-formation anodization ST3B until 250V is reached, and then providing the crack formation treatment ST11 to apply stress to the aluminum foil 10, it becomes easier to uniformly form a plurality of cracks 7 on the surface of the porous layers (the first porous layer 3 and the second porous layer 4).
In the crack formation process ST11, stress is generated in the aluminum foil 10 by the crack formation rollers (the first crack formation roller 21(1) and the second crack formation roller 21 (2)). This facilitates formation of a plurality of cracks 7 in the porous layers (first porous layer 3 and second porous layer 4).
In the crack formation process ST11, among the plurality of rollers 21 for running the aluminum foil 10, the rollers 21 having a smaller diameter than the other rollers 21 are arranged as the crack formation rollers (the first crack formation roller 21(1) and the second crack formation roller 21 (2)). By using small-diameter rollers as the crack-forming rollers (the first crack-forming roller 21(1) and the second crack-forming roller 21(2)), the aluminum foil 10 is easily stressed to form the crack 7.
In addition, in the first and fifth manufacturing methods, the formation process ST1 includes a hydration process ST2 of forming a hydration film on the aluminum foil 10 before the anodizing process ST 3. Further, a crack formation process ST11 is performed in the middle of the hydration process ST 2. With this arrangement, first, in the hydration step ST2, a hydrated film is formed on the surface of the porous layers (the first porous layer 3 and the second porous layer 4). Then, in the middle of hydration step ST2, cracks 7 are provided in the porous layers (first porous layer 3 and second porous layer 4). Thus, by the crack formation process ST11, the aluminum newly grown surface (the surface of the bare metal aluminum) is exposed to the surface of the porous layers (first porous layer 3 and second porous layer 4) by the crack 7. That is, the powder 11 having no hydrated film formed on the surface thereof is exposed to the fracture surface of the porous layer (the first porous layer 3 and the second porous layer 4) formed by the crack 7. Then, in the hydration step ST2, which is continued after the crack formation process ST11, a hydrated film is formed on the aluminum green surface. Here, the hydrated film covering the aluminum green surface prevents or suppresses the powder 11 on both sides with the crack 7 interposed therebetween from being bonded to each other by the chemical conversion film (the first chemical conversion film 5 and the second chemical conversion film 6) in the anodizing step ST 3. Therefore, by performing the crack formation process ST11 in the middle of the hydration process ST2, when the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) are grown in the crack formation process ST11 and the anodization process ST3 performed after the hydration process ST2, it is possible to prevent or suppress the closure of the crack 7 by the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6).
In the second, third, and fourth manufacturing methods, the formation process ST1 includes a hydration process ST2 of forming a hydration film on the aluminum foil 10 before the anodic oxidation process ST 3. In the anodizing step ST3, the aluminum foil 10 on which the hydrated film is formed is anodized. In the second and third manufacturing methods, the hydration step ST2 is followed by the crack formation step ST 11. With this arrangement, in the hydration step ST2, a hydrated film is formed on the surface of the porous layer (first porous layer 3 and second porous layer 4). Here, the hydrated film inhibits or suppresses the bonding of the powder 11 to each other by the chemical conversion film (the first chemical conversion film 5 and the second chemical conversion film 6) in the anodizing step ST 3. Therefore, by having the crack formation treatment ST11 after the hydration step ST2, it is easy to suppress the closing of the cracks 7 formed in the porous layers (the first porous layer 3 and the second porous layer 4) due to the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) formed after the hydration step ST 2.
In the fourth and fifth manufacturing methods, in the anodizing step ST3, the pre-crack-formation anodizing process ST3B is performed until a predetermined anodizing voltage is reached, and then the crack-formation process ST11 is performed. Further, after the crack formation process ST11, a rehydration process ST21 of forming a hydrated film on the aluminum foil 10 is continuously performed. Further, post-anodizing treatment ST3A is performed after rehydration treatment ST 21. With this arrangement, in the hydration step ST2, a hydrated film is formed on the surface of the porous layer (first porous layer 3 and second porous layer 4). Here, the hydrated film inhibits or suppresses the bonding of the powder 11 to each other by the chemical conversion film (the first chemical conversion film 5 and the second chemical conversion film 6) in the anodizing step ST 3. This makes it easy to suppress the closing of the chemical conversion coatings (first chemical conversion coating 5 and second chemical conversion coating 6) of the cracks 7 formed in the porous layers (first porous layer 3 and second porous layer 4). In addition, in the rehydration process ST21 that is continued after the crack formation process ST11, a hydrated film is formed on the aluminum fresh surface where the surfaces of the porous layers (first porous layer 3 and second porous layer 4) are exposed by the formation of the crack 7. Here, the hydrated film covering the aluminum green surface prevents or suppresses the powder 11 on both sides with the crack 7 interposed therebetween from being bonded to each other by the chemical film (the first chemical film 5 and the second chemical film 6) in the subsequent anodic oxidation. Therefore, by performing the rehydration process ST21 after the crack formation process ST11, when the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) grow in the post-anodizing process ST3A, the closing of the crack 7 by the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) can be further suppressed.
In each of the manufacturing methods, after the anodizing step ST3 is completed, the aluminum foil 10 after being formed, that is, the formed aluminum foil 1 is wound around a winding roll to form a roll shape wound in a spiral curve. At this time, the aluminized foil 1 has a plurality of cracks 7, and is easily wound in the X direction. Therefore, the aluminized foil 1 can be wound in a shape close to a perfect circle as compared with the case where the aluminized foil 1 does not have the crack 7. That is, when the aluminized foil 1 having no crack is wound, a plurality of bent portions are formed in the middle of the aluminized foil 1. On the other hand, when the aluminized foil 1 having the plurality of cracks 7 is wound, the roll shape wound in the X direction can be formed, and the bent portion is not provided in the middle. As a result, the roll formed by winding the chemical conversion aluminum foil 1 has a smaller outer dimension of the roll formed by winding the chemical conversion aluminum foil 1 with respect to the dimension in the X direction than the roll formed by winding the chemical conversion aluminum foil 1 without cracks. In other words, when the roll is wound to have the same outer dimension, the roll wound with the aluminized foil 1 has a longer dimension in the X direction of the aluminized foil 1 after winding than the roll in which the aluminized foil 1 has no cracks. Therefore, in this example, the work efficiency of the winding work of the converted aluminum foil 1 into a roll can be improved. Further, by winding the aluminized foil 1 in a spiral curve shape to form a roll shape, it is possible to prevent the aluminized foil 1 from breaking at a bent portion, as compared with a case where the aluminized foil 1 has a bent portion in the middle. Therefore, the wrappability of the aluminized foil 1 can be improved.
(examples)
Fig. 13 is a table showing the timing of performing the crack formation process ST11 in the method for producing the aluminum foil 1 of examples 1 to 5. Fig. 14 is an explanatory view of the timing of performing the crack formation process ST11 in the method for producing the aluminum foil 1 of examples 1 to 5. Although the timing of performing the crack formation process ST11 differs in the method for producing the aluminum formed foil 1 of examples 1 to 5, the process performed on the aluminum foil 10 in the formation step ST1 is the same.
In examples 1 to 5, aluminum foil 10 having thickness T1 of base layer 2 of 30 μm, thickness T2 of first porous layer 3 and thickness T3 of second porous layer 4 of 50 μm, respectively, and average particle diameter K of powder 11 forming first porous layer 3 and second porous layer 4 of 3 μm was used as a base material. In the hydration process ST2, pure water is used as the hydration treatment solution. In the hydration step ST2, the aluminum foil 10 is boiled at 95 ℃ for 10 minutes. In the anodizing process ST3, the first anodizing process ST41, the second anodizing process ST42, and the third anodizing process ST43 are performed. In the anodizing process ST3, a heat treatment ST31 is performed between the second anodizing process ST42 and the third anodizing process ST 43. In the heat treatment ST31, the aluminum foil 10 is heated in an atmosphere at 500 ℃ for 2 minutes to expose the defective portion.
In the first anodizing treatment ST41, the aluminum foil 10 is anodized until the anodizing voltage reaches 400V. The chemical conversion treatment liquid of the first anodizing treatment ST41 contains ammonium adipate. The amount of ammonium adipate in the chemical conversion treatment liquid was 1 g/L. The temperature of the chemical conversion treatment liquid is 80 ℃. In the second anodizing treatment ST42, the anodizing voltage was increased to 550V and maintained for 30 minutes, thereby anodizing the aluminum foil 10. The chemical conversion treatment liquid of the second anodizing treatment ST42 contains boric acid and ammonium pentaborate octahydrate. The amount of boric acid in the chemical conversion treatment liquid was 80g/L, and the amount of ammonium pentaborate octahydrate was 0.5 g/L. The temperature of the chemical conversion treatment liquid is 80 ℃. In the third anodization ST43, the anodization voltage is increased to 550V and maintained for 10 minutes, thereby anodizing the aluminum foil 10. In the third anodizing treatment ST43, the same chemical conversion treatment liquid as in the second anodizing treatment ST42 was used. The temperature of the chemical conversion treatment liquid is 80 ℃. The diameter M of the first crack-forming roll 21(1) and the diameter M of the second crack-forming roll 21(2) used in the crack-forming process ST11 were 10 mm.
As shown in fig. 13 and 14, example 1 is the first production method, and has a crack formation process ST11 in the middle of the hydration step ST 2. Example 2 is a second manufacturing method, and has a crack formation process ST11 between the hydration process ST2 and the anodization process ST 3. In examples 1 and 2, the first anodizing treatment ST41, the second anodizing treatment ST42, and the third anodizing treatment ST43 correspond to the post-anodizing treatment ST 3A.
Examples 3 to 5 are the third manufacturing method, and in the anodizing process ST3 included in the formation process ST1, the crack formation process ST11 was performed until the final target anodizing voltage (550V) was reached.
In example 3, in the first anodizing treatment ST41, the crack forming treatment ST11 was performed at a point of time when the anodizing voltage reached 100V. In example 3, the anodization voltage of the first anodization ST41 was 100V, which corresponds to the pre-anodization ST3B, and the second anodization ST42 and the third anodization ST43 correspond to the post-anodization ST3A after the crack formation ST11 of the first anodization ST 41.
In example 4, in the first anodizing treatment ST41, the crack forming treatment ST11 was performed at a point of time when the anodizing voltage reached 200V. In example 4, the anodization voltage of the first anodization ST41 was equivalent to the pre-anodization ST3B until it reached 200V, and the second anodization ST42 and the third anodization ST43 were equivalent to the post-anodization ST3A after the crack formation ST11 of the first anodization ST 41.
In example 5, in the first anodizing treatment ST41, the crack forming treatment ST11 was performed at a point of time when the anodizing voltage reached 400V. In example 5, the anodization voltage of the first anodization ST41 reached 400V corresponds to the pre-anodization ST3B, and the second anodization ST42 and the third anodization ST43 correspond to the post-anodization ST 3A.
In the manufacturing method of comparative example 1, the crack formation process ST11 was not performed in the middle of the formation step ST 1. In the manufacturing method of comparative example 2, in the anodizing process ST3, the crack forming process ST11 was performed immediately after the second anodizing process ST 42. In the manufacturing method of comparative example 2, at the time point of performing the crack formation process ST11, the voltage output from the power supply at the time of anodization exceeded the predetermined anodization voltage (400V), and reached the final anodization voltage (550V), which is the final target of the voltage at the time of anodization.
Fig. 15 is a table showing the intervals of cracks 7, the bending strength, the tensile strength, the capacitance, and the coating withstand voltage of the aluminum foil 10 after the chemical conversion treatment, i.e., the aluminized foil 1, with respect to examples 1 to 5 and comparative examples 1 and 2. The manufacturing method of comparative example 1 does not include the crack formation process ST 11. Therefore, as shown in fig. 15, the aluminized foil 1 obtained by the manufacturing method of comparative example 1 has no cracks in the first porous layer 3 and the second porous layer 4. Therefore, the column of the interval between cracks in fig. 15 indicates that measurement cannot be performed.
Here, the bending strength, tensile strength and electrostatic capacity were measured in accordance with the Japanese electronic mechanical Association Standard "EIAJ RC-2364A". The bending strength is represented by the number of times of bending when the aluminized foil 1 is broken. The number of times of bending was counted as 1 for 90 ° of bending of the aluminized foil 1 extending in the X direction in the Z direction intersecting the X direction and the Y direction, 2 for bending recovery, 3 for 90 ° of bending in the Z direction opposite to the first, and 4 for bending recovery. After 5 times, the number of bends was counted in the same manner as 1 to 4 times. The tensile strength is a tensile force at the time of breaking when the aluminum-formed foil 1 is stretched in the X direction.
Fig. 16 is a photograph of the surface of the aluminized foil 1 manufactured by the manufacturing method of example 5 taken by a scanning electron microscope at an enlarged scale. Fig. 1 is a photograph of the surface of the aluminized foil 1 produced by the production method of example 1 taken under magnification by a scanning electron microscope. Fig. 2 is a photograph of a cross section of the aluminized foil 1 manufactured by the manufacturing method of example 1 taken by a scanning electron microscope at an enlarged scale.
As shown in fig. 1, 2, and 16, in the aluminized foil 1 obtained by the manufacturing methods of examples 1 to 5, a plurality of cracks 7 extending in the Y direction with a length of 300 μm or more were provided on the surfaces of the first porous layer 3 and the second porous layer 4 at intervals of 30 μm to 150 μm. Specifically, as shown in FIG. 15, a plurality of cracks 7 are provided at intervals of 95 to 110 μm.
In the case of the aluminum formed foil 1, even when the aluminum foil 10 is bent when the adjacent powders 11 are bonded by the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) by anodizing the aluminum foil 10, the stress due to the deformation can be released from the crack 7. Therefore, in the aluminized foil 1 obtained by the manufacturing methods of examples 1 to 5, the bending strength was 150 times or more, and the aluminized foil 1 was more resistant to bending than the aluminized foil 1 obtained by the manufacturing methods of comparative examples 1 and 2.
Here, in the aluminized foil 1 (see fig. 1) obtained by the manufacturing methods of examples 1 to 4, the intervals of the cracks 7 were narrower than the aluminized foil 1 (see fig. 16) obtained by the manufacturing method of example 5. Therefore, as shown in fig. 15, the number of times of bending indicating the bending strength was larger than that of the aluminized foil 1 obtained by the manufacturing method of example 5, and the aluminum foil was more resistant to bending. Here, according to the verification of the inventors, if the crack formation process ST11 is performed until the anodization voltage reaches 250V in the anodization step ST3, the aluminized foil 1 can be made more resistant to bending than the case where the crack formation process ST11 is performed after the anodization voltage exceeds 250V.
In addition, when the aluminized foil 1 obtained by the manufacturing methods of examples 1 to 5 was used as an electrode for an aluminum electrolytic capacitor, the electrostatic capacity was higher than that when the aluminized foil obtained by the manufacturing method of comparative example 1 was used as an electrode for an aluminum electrolytic capacitor. That is, the aluminized foil 1 obtained by the manufacturing methods of examples 1 to 5 has the cracks 7, and thus has a larger specific surface area than the aluminized foil 1 obtained by the manufacturing method of comparative example 1. As a result, the aluminum foil 1 (electrode for aluminum electrolytic capacitor) obtained by the production methods of examples 1 to 5 had a high capacitance.
Here, fig. 17 is a photograph of the surface of the aluminized foil 1' produced by the production method of comparative example 1 taken under magnification by a scanning electron microscope. Fig. 18 is a photograph of a cross section of the aluminized foil 1' of comparative example 1 taken by an enlargement of a scanning electron microscope. As shown in fig. 17 and 18, the aluminized foil 1' produced by the production method of comparative example 1 has no cracks. In the case of the aluminum chemical foil 1', when the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) are grown on the surfaces of the porous layers (the first porous layer 3 and the second porous layer 4) including the sintered body of the powder 11 in the anodizing step ST3, the adjacent powders 11 are bonded by the chemical conversion coatings. Therefore, when the aluminum foil is bent, the powder 11 is strongly bonded to each other, and thus stress due to deformation cannot be released from the aluminum foil. As a result, the bonding between the powders 11 is locally broken. Moreover, the crack propagates, breaking the aluminum foil. Therefore, as shown in fig. 15, the aluminized foil 1' produced by the production method of comparative example 1 has low bending strength.
Fig. 19 is a table showing the timing of performing the crack formation process ST11 in the method for producing the aluminum foil 1 of examples 6 to 8. Fig. 20 is an explanatory view of the timing of performing the crack formation process ST11 in the method for producing the aluminum formed foil 1 of examples 6 to 8.
Examples 6 to 8 are fourth manufacturing methods in which, in the anodizing step ST3 included in the formation step ST1, the crack formation treatment ST11 and the rehydration treatment ST21 were continuously performed until the final target final anodizing voltage (550V) was reached. In examples 6 to 8, the aluminum foil 10 used as the base material was the same as in examples 1 to 5. That is, in examples 6 to 8, aluminum foil 10 having thickness T1 of base layer 2 of 30 μm, thickness T2 of first porous layer 3 and thickness T3 of second porous layer 4 of 50 μm, respectively, and average particle diameter K of powder 11 forming first porous layer 3 and second porous layer 4 of 3 μm was used as a base material.
In the methods for producing the aluminum foil 1 according to examples 6 to 8, the treatment of the aluminum foil 10 in the forming step ST1 is the same as in examples 1 to 5. The diameter M of the first crack-forming roll 21(1) and the diameter M of the second crack-forming roll 21(2) used in the crack-forming process ST11 were 10 mm. In the rehydration process ST21, pure water is used as the hydration process liquid. Also, in the rehydration process ST21, the aluminum foil 10 was boiled at 95 ℃ for 2 minutes.
Here, in example 6, in the first anodizing treatment ST41, the crack forming treatment ST11 and the rehydration treatment ST21 were continuously performed at the time point when the anodizing voltage reached 100V. In example 6, the anodization voltage of the first anodization ST41 reached 100V corresponded to the pre-anodization ST3B, and the second anodization ST42 and the third anodization ST43 corresponded to the post-anodization ST3A after the crack formation ST11 and rehydration ST21 of the first anodization ST 41.
In example 7, in the first anodizing treatment ST41, the crack forming treatment ST11 and the rehydrating treatment ST21 were continuously performed at the time point when the anodizing voltage reached 200V. In example 7, the anodization voltage of the first anodization ST41 was equivalent to the pre-anodization ST3B until it reached 200V, and the second anodization ST42 and the third anodization ST43 were equivalent to the post-anodization ST3A after the crack formation ST11 and rehydration ST21 of the first anodization ST 41.
In example 8, in the first anodizing treatment ST41, the crack forming treatment ST11 and the rehydrating treatment ST21 were continuously performed at the time point when the anodizing voltage reached 400V. In example 8, the anodization voltage of the first anodization ST41 reached 400V corresponds to the pre-anodization ST3B, and the second anodization ST42 and the third anodization ST43 correspond to the post-anodization ST 3A.
Fig. 21 is an explanatory view showing the interval of cracks 7, the bending strength, the tensile strength, the capacitance, and the coating withstand voltage of the aluminum foil 10, i.e., the chemical conversion foil 1, after the chemical conversion treatment in examples 6 to 8. In the aluminized foil 1 obtained by the manufacturing methods of examples 6 to 8, a plurality of cracks 7 extending in the Y direction with a length of 300 μm or more were provided on the surfaces of the first porous layer 3 and the second porous layer 4 at intervals of 30 μm to 150 μm. That is, as shown in fig. 21, in the aluminized foil 1 obtained by the manufacturing methods of examples 6 to 8, a plurality of cracks 7 were provided at intervals of 105 μm to 110 μm. Therefore, even when the aluminum foil 10 is bent when the adjacent powders 11 are bonded by the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) by anodizing the aluminum foil 10, the stress due to the deformation can be released from the crack 7.
Therefore, the aluminized foil 1 obtained by the manufacturing methods of examples 6 to 8 had a bending strength of 161 times or more, and was more resistant to bending than the aluminized foil 1 obtained by the manufacturing methods of comparative examples 1 and 2.
Further, in the aluminized foil 1 obtained by the manufacturing methods of examples 6 to 8, since the crack formation treatment ST11 and the rehydration treatment ST21 are successively performed in this order, when the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) are grown in the anodizing step ST3, the closure of the crack 7 by the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) can be prevented or suppressed. Further, since the chemical conversion coating (the first chemical conversion coating 5 and the second chemical conversion coating 6) has the cracks 7, when the aluminized foil 1 obtained by the manufacturing methods of examples 6 to 8 is used as an electrode for an aluminum electrolytic capacitor, the electrostatic capacity is higher than that when the aluminized foil 1 obtained by the manufacturing methods of comparative examples 1 and 2 is used as an electrode for an aluminum electrolytic capacitor.
Here, in the aluminized foil 1 obtained by the manufacturing methods of examples 6 and 7, the interval of the crack 7 was narrower than that of the aluminized foil 1 obtained by the manufacturing method of example 8. Therefore, as shown in fig. 21, the number of times of bending indicating the bending strength of the aluminized foil 1 obtained by the manufacturing methods of examples 6 and 7 is larger than that of the aluminized foil 1 obtained by the manufacturing method of example 8, and the aluminized foil 1 is more resistant to bending. Further, according to the verification of the inventors, in the anodizing process ST3, by performing the crack formation treatment ST11 and the rehydration treatment ST21 until the anodizing voltage reaches 250V, the aluminized foil 1 can be made more resistant to bending than in the case where the crack formation treatment ST11 is performed after the anodizing voltage exceeds 250V.
FIG. 22 is a table showing the timing of performing the crack formation process ST11 in the method for producing the aluminized foil 1 according to examples 9 to 11. FIG. 23 is an explanatory view of the timing of performing the crack formation process ST11 in the method for producing the aluminized foil 1 according to examples 9 to 11.
Examples 9 to 11 are fifth production methods in which the crack formation treatment ST11 was performed in the middle of the hydration step ST2 included in the formation step ST 1. In examples 9 to 11, the anodization step ST3 included in the chemical conversion step ST1 was performed by continuously performing the crack formation treatment ST11 and the rehydration treatment ST21 until the voltage output from the power supply reached the final target anodization voltage (550V). In examples 9 to 11, aluminum foil 10 having thickness T1 of base layer 2 of 30 μm, thickness T2 of first porous layer 3 and thickness T3 of second porous layer 4 of 100 μm, and average particle diameter K of powder 11 forming first porous layer 3 and second porous layer 4 of 3 μm was used as a base material. That is, in examples 9 to 11, aluminum foil 10 having a porous layer thickness dimension (the sum of thickness dimension T2 of first porous layer 3 and thickness dimension T3 of second porous layer 4) of 200 μm was used as a base material.
In examples 9 to 11, the treatment of the aluminum foil 10 in the forming step ST1 was the same as in examples 1 to 8. The diameter M of the first crack forming roller 21(1) and the diameter M of the second crack forming roller 21(2) used in the crack forming process ST11 were 10 mm. In the rehydration ST21, pure water is used as the hydration treatment liquid. In the rehydration process ST21, the aluminum foil 10 is boiled at 95 ℃ for 2 minutes.
Here, in example 9, in the first anodizing treatment ST41, the crack forming treatment ST11 and the rehydrating treatment ST21 were continuously performed at the time point when the anodizing voltage reached 100V. In example 9, the anodization voltage of the first anodization ST41 reached 100V corresponded to the pre-anodization ST3B, and the second anodization ST42 and the third anodization ST43 corresponded to the post-anodization ST3A after the crack formation ST11 and rehydration ST21 of the first anodization ST 41.
In example 10, in the first anodizing treatment ST41, the crack-forming treatment ST11 and the rehydration treatment ST21 were continuously performed at the time point when the anodizing voltage reached 200V. In example 10, the anodization voltage of the first anodization ST41 was equivalent to the pre-anodization ST3B until it reached 200V, and the second anodization ST42 and the third anodization ST43 were equivalent to the post-anodization ST3A after the crack formation ST11 and rehydration ST21 of the first anodization ST 41.
In example 11, in the first anodizing treatment ST41, the crack-forming treatment ST11 and the rehydration treatment ST21 were continuously performed at the time point when the anodizing voltage reached 400V. In example 11, the anodization voltage of the first anodization ST41 reached 400V corresponded to the pre-anodization ST3B, and the second anodization ST42 and the third anodization ST43 corresponded to the post-anodization ST 3A.
Fig. 24 is an explanatory view showing the intervals of cracks 7, the bending strength, the tensile strength, the capacitance, and the coating withstand voltage of the aluminum foil 10, i.e., the chemical conversion foil 1, after the chemical conversion treatment in examples 9 to 11. In the aluminized foil 1 obtained by the manufacturing methods of examples 9 to 11, a plurality of cracks 7 extending in the Y direction with a length of 300 μm or more were provided at intervals of 35 μm to 150 μm on the surfaces of the first porous layer 3 and the second porous layer 4. That is, as shown in fig. 24, a plurality of cracks 7 are provided at intervals of 135 to 150 μm. In the case of the aluminum formed foil 1, even when the aluminum foil 10 is bent when the adjacent powders 11 are bonded by the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) by anodizing the aluminum foil 10, the stress due to the deformation can be released from the crack 7.
Therefore, the aluminized foil 1 obtained by the manufacturing methods of examples 9 to 11 had a bending strength of 120 or more times, and was more resistant to bending than the aluminized foil 1 obtained by the manufacturing methods of comparative examples 1 and 2.
Further, the aluminized foil 1 obtained by the manufacturing methods of examples 9 to 11 was subjected to the 2-time crack formation process ST11, and the first crack formation process ST11 was performed in the middle of the hydration step ST2, and the rehydration process ST21 was continuously performed after the crack formation process ST11 in the second crack formation process ST 11. Therefore, even when the aluminum foil 10 having the porous layer thickness dimension (the sum of the thickness dimension T2 of the first porous layer 3 and the thickness dimension T3 of the second porous layer 4) of 200 μm is used as the substrate, it is possible to prevent or suppress the closure of the crack 7 by the chemical conversion coating (the first chemical conversion coating 5 and the second chemical conversion coating 6) when the chemical conversion coating (the first chemical conversion coating 5 and the second chemical conversion coating 6) is grown in the anodic oxidation step ST 3.
Further, since the chemical conversion coating (the first chemical conversion coating 5 and the second chemical conversion coating 6) has the cracks 7, when the aluminized foil 1 obtained by the manufacturing methods of examples 9 to 11 is used as an electrode for an aluminum electrolytic capacitor, the electrostatic capacity is higher than that when the aluminized foil 1 obtained by the manufacturing methods of comparative examples 1 and 2 is used as an electrode for an aluminum electrolytic capacitor.
Here, in the aluminized foil 1 obtained by the manufacturing methods of examples 9 and 10, the interval of the crack 7 was narrower than that of the aluminized foil 1 obtained by the manufacturing method of example 11. Therefore, as shown in fig. 24, the number of times of bending indicating the bending strength of the aluminized foil 1 obtained by the manufacturing methods of examples 9 and 10 is larger than that of the aluminized foil 1 obtained by the manufacturing method of example 11, and the aluminized foil 1 is more resistant to bending. Further, according to the verification of the inventors, in the anodizing step ST3, by performing the crack formation treatment ST11 and the rehydration treatment ST21 until the anodizing voltage reaches 250V, the aluminized foil 1 can be made more resistant to bending than in the case where the crack formation treatment ST11 is performed after the anodizing voltage exceeds 250V.
In examples 8 to 11, the porous layers (the first porous layer 3 and the second porous layer 4) laminated on the base layer 2 aluminized to the foil 1 were thick. Therefore, when the formed aluminum foil 1 produced by the production methods of examples 8 to 11 was used as an electrode for an aluminum electrolytic capacitor, the electrostatic capacity was higher than that when the formed aluminum foil 1 obtained by the production methods of other examples was used as an electrode for an aluminum electrolytic capacitor.
(other embodiments)
Fig. 25 is a flowchart of a sixth manufacturing method of the aluminized foil 1. Fig. 26 is a flowchart of a seventh manufacturing method of the aluminized foil 1. The sixth manufacturing method of aluminized foil 1 includes, in addition to the second manufacturing method shown in fig. 8, a rehydration process ST21 in which a hydrated film is formed on aluminum foil 10 after the crack formation process ST 11. That is, as shown in fig. 25, in the sixth manufacturing method of aluminized foil 1, crack formation treatment ST11 and rehydration treatment ST21 are continuously performed between hydration step ST2 and anodic oxidation step ST 3. By this arrangement, a hydrated coating can be provided by the rehydration process ST21 with respect to the aluminum green surface exposed by the crack 7 provided by the crack formation process ST 11. Therefore, when the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) are grown in the post-anodizing treatment ST3A in the subsequent anodizing step ST3, it is easy to prevent or suppress the closure of the crack 7 by the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6).
In the pre-anodization ST3B performed before the crack formation ST11, the hydration step ST2 may be omitted when the predetermined anodization voltage reached when the anodization is performed before the crack formation ST11 is low, for example, when the predetermined anodization voltage is 5V or more and 150V or less. That is, the formation step ST1 may include only the anodization step ST 3.
In the manufacturing method of the seventh manufacturing method, as shown in fig. 26, in the anodizing step ST3, the crack formation process ST11 is performed by performing the pre-anodizing process ST3B of anodizing the aluminum foil 10 until the predetermined anodizing voltage is reached, and then performing the crack formation process ST 11. After the crack formation process ST11, a post-anodization process ST3A is performed. With this arrangement, a plurality of cracks 7 extending in the Y direction (Y direction) at a length of 300 μm or more can be provided on the surface of first porous layer 3 at intervals of 30 μm to 150 μm in the X direction (X direction). Further, a plurality of cracks 7 extending in the Y direction at a length of 300 μm or more can be provided on the surface of second porous layer 4 at intervals of 30 μm to 150 μm in the X direction orthogonal to the Y direction. Therefore, even when the aluminum foil 10 is bent when the adjacent powders 11 are bonded by the chemical conversion coatings (the first chemical conversion coating 5 and the second chemical conversion coating 6) by anodizing the aluminum foil 10, the stress due to the deformation can be released from the crack 7.
In the method for producing the aluminum foil 1 described with reference to fig. 7 to 11, 25, and 26, the case where the heat treatment ST31 is performed after the post-anodization ST3A is exemplified. The heat treatment ST31 may be performed before the pre-anodization ST3B or after it is performed as long as it is performed in the middle of the anodization step ST3, or may be performed before or after the post-anodization ST 3A. The heat treatment ST31 may be performed during the pre-anodization ST3B or during the post-anodization ST 3A. Further, the heat treatment ST31 may be omitted.
As the base material of the aluminized foil 1, an aluminum foil 10 having only the base layer 2 and the first porous layer 3 laminated on the first surface 2a of the base layer 2 may be used. In this case, in the crack formation process ST11 performed in the middle of the chemical conversion process ST1, the cracks 7 are provided in the first porous layer 3 using only the first crack formation roller 21 (1).
In the crack formation process ST11, the first crack formation roller 21(1) and the second crack formation roller 21(2) may be brought into contact with each other with respect to the aluminum foil 10, and either one of the first crack formation roller 21(1) and the second crack formation roller 21(2) may be moved to generate stress in the aluminum foil 10. That is, in the crack formation process ST11, the crack 7 can be imparted to the aluminum foil 10 by relatively moving the aluminum foil 10, the first crack formation roller 21(1), and the second crack formation roller 21(2) in the X direction.
In the crack formation process ST11, the aluminum foil 10 may be advanced by bringing the aluminum foil 10 into contact with the first crack formation roller 21(1) or the second crack formation roller 21(2) at a predetermined wrap angle. That is, the aluminum foil 10 may be applied with stress by the first crack forming roller 21(1) contacting the second surface 2b of the aluminum foil 10 or the second crack forming roller 21(2) contacting the first surface 2a without running between the first crack forming roller 21(1) or the second crack forming roller 21(2) and the pressing roller 23. In this case, the wrap angle of the first crack forming roller 21(1) and the wrap angle of the second crack forming roller 21(2) may be generally greater than 0 ° and 180 ° or less. In this case, the wrap angle of the first crack forming roller 21(1) and the wrap angle of the second crack forming roller 21(2) are preferably greater than 0 ° and 45 ° or less. When the wrap angle of first crack-forming roller 21(1) and the wrap angle of second crack-forming roller 21(2) are within the above-described ranges, desired cracks 7 are easily formed in first porous layer 3 or second porous layer 4.
Here, the aluminized foil 1 of the present invention can be used as a diffusion member for diffusing a liquid such as a sample solution or blood on the surface thereof. At this time, the aluminized foil 1 has the cracks 7 on the surface, and therefore the liquid is easily diffused.
Claims (22)
1. An aluminized foil comprising:
an aluminum foil in which a first porous layer containing a sintered body of a powder of aluminum or an aluminum alloy is laminated on a first surface of both surfaces of a foil-shaped base layer containing aluminum or an aluminum alloy; and
a first chemical coating film formed on the first porous layer,
a plurality of cracks extending in a first direction at a length of 300 [ mu ] m or more in an in-plane direction are provided at intervals of 30 [ mu ] m to 150 [ mu ] m in a second direction perpendicular to the first direction in the in-plane direction on the surface of the first porous layer.
2. The aluminized foil of claim 1, wherein:
the plurality of cracks each reach a boundary between the base layer and the first porous layer.
3. The aluminized foil of claim 1 or 2, wherein:
the dimension of the aluminum foil in the second direction is longer than the dimension in the first direction.
4. The aluminized foil of any one of claims 1 to 3, wherein:
the first porous layer has a thickness of 10 [ mu ] m or more and 500 [ mu ] m or less.
5. The aluminized foil of any one of claims 1 to 4, wherein:
the average particle diameter of the powder is more than 1 μm and less than 20 μm.
6. The aluminized foil of any one of claims 1 to 5, wherein:
the thickness of the base layer is 10 [ mu ] m or more and 100 [ mu ] m or less.
7. The aluminized foil of any one of claims 1 to 6, wherein:
a second porous layer in which a sintered body of a powder containing aluminum or an aluminum alloy is laminated on a second surface of the base layer opposite to the first surface,
a second chemical coating is formed on the second porous layer,
on the surface of the second porous layer, a plurality of the cracks extending in the in-plane direction thereof are provided at the intervals.
8. An electrode for an aluminum electrolytic capacitor, characterized in that:
comprising an aluminized foil according to any one of claims 1 to 7.
9. The electrode for an aluminum electrolytic capacitor as recited in claim 8, wherein:
the aluminized foil is wound in a roll shape having a spiral curve in the second direction.
10. An aluminized foil comprising:
an aluminum foil in which a first porous layer containing a sintered body of a powder of aluminum or an aluminum alloy is laminated on a first surface of both surfaces of a foil-shaped base layer containing aluminum or an aluminum alloy; and
a first chemical coating film formed on the first porous layer,
a plurality of cracks extending in a first direction of in-plane directions are provided on a surface of the first porous layer so as to be separated in the in-plane direction and in a second direction orthogonal to the first direction,
the plurality of cracks each reach a boundary between the base layer and the first porous layer.
11. An electrode for an aluminum electrolytic capacitor, characterized in that:
comprising the aluminized foil of claim 10.
12. The electrode for an aluminum electrolytic capacitor as recited in claim 11, wherein:
the aluminized foil is wound in a roll shape having a spiral curve in the second direction.
13. A method of making an aluminized foil, comprising:
comprises a formation step of forming a first formation film on an aluminum foil having a first porous layer in which a sintered body of a powder containing aluminum or an aluminum alloy is laminated on a first surface of both surfaces of a foil-shaped base layer containing aluminum or an aluminum alloy,
the formation step includes an anodic oxidation step of anodizing the aluminum foil,
performing a crack formation process in which stress is generated in the aluminum foil in the formation step, and a plurality of cracks extending in a first direction are provided on a surface of the first porous layer so as to be separated in a second direction orthogonal to the first direction,
in the anodizing step, a post-crack-formation anodizing treatment is performed, and the post-crack-formation anodizing treatment is a treatment of anodizing the aluminum foil after the crack formation treatment.
14. The method of making aluminized foil according to claim 13, wherein:
in the crack formation process, a plurality of the cracks extending in the first direction at a length of 300 μm or more are provided at intervals of 30 to 150 μm in the second direction.
15. The method for manufacturing an aluminized foil according to claim 13 or 14, wherein:
in the crack formation process, each crack is caused to reach a boundary between the base layer and the first porous layer.
16. The method of producing an aluminized foil according to any one of claims 13 to 15, wherein:
in the anodizing step, a pre-crack-formation anodizing treatment of anodizing the aluminum foil to a predetermined anodizing voltage before the crack formation treatment is performed,
the predetermined anodization voltage in the pre-crack-formation anodization is 400V or less.
17. The method of manufacturing an aluminized foil according to any one of claims 13 to 16, comprising:
in the crack formation process, a first crack formation roller extending in the first direction is brought into contact with a second surface of the aluminum foil opposite to the first surface, and the aluminum foil and the first crack formation roller are relatively moved in the second direction.
18. The method of making aluminized foil according to claim 17, wherein:
in the forming step, the aluminum foil is advanced in the second direction by a plurality of rollers arranged along the second direction,
among the plurality of rollers, a roller having a smaller diameter than the other rollers is disposed as the first crack-forming roller.
19. The method of making aluminized foil according to claim 17 or 18, wherein:
in the aluminum foil, a second porous layer containing a sintered body of a powder of aluminum or an aluminum alloy is laminated on a second surface of the base layer opposite to the first surface,
in the formation step, a second formation film is formed on the second porous layer,
in the crack formation process, a second crack formation roller extending in the first direction is brought into contact with the first surface at a position different from the first crack formation roller in the second direction, and the aluminum foil and the second crack formation roller are moved relative to each other in the second direction.
20. The method of manufacturing an aluminized foil according to any one of claims 13 to 19, comprising:
the formation step includes a hydration step of forming a hydrated film on the aluminum foil before the anodic oxidation step,
in the anodic oxidation step, the aluminum foil on which the hydrated film is formed is subjected to anodic oxidation,
the crack formation treatment is performed in the middle of the hydration step.
21. The method of manufacturing an aluminized foil according to any one of claims 13 to 19, comprising:
the formation step includes a hydration step of forming a hydrated film on the aluminum foil before the anodic oxidation step,
in the anodic oxidation step, the aluminum foil on which the hydrated film is formed is subjected to anodic oxidation,
the crack formation treatment is performed after the hydration process.
22. The method of making aluminized foil according to claim 21, wherein:
including a rehydration treatment that forms a hydrated film on the aluminum foil after the crack formation treatment.
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| JP2005175330A (en) * | 2003-12-15 | 2005-06-30 | Nichicon Corp | Manufacturing method of anode foil for aluminum electrolytic capacitor |
| CN103658660A (en) * | 2012-09-25 | 2014-03-26 | 日本轻金属株式会社 | Porous aluminum body, aluminum electrolytic capacitor, and manufacturing method of porous aluminum body |
| CN105874549A (en) * | 2013-12-27 | 2016-08-17 | 东洋铝株式会社 | Electrode foil for aluminum electrolytic capacitor and production method for same |
| CN108431916A (en) * | 2016-03-31 | 2018-08-21 | 日本贵弥功株式会社 | The manufacturing method of electrode foil, convoluted capacitor, the manufacturing method of electrode foil and convoluted capacitor |
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| JP2005175330A (en) * | 2003-12-15 | 2005-06-30 | Nichicon Corp | Manufacturing method of anode foil for aluminum electrolytic capacitor |
| CN103658660A (en) * | 2012-09-25 | 2014-03-26 | 日本轻金属株式会社 | Porous aluminum body, aluminum electrolytic capacitor, and manufacturing method of porous aluminum body |
| CN105874549A (en) * | 2013-12-27 | 2016-08-17 | 东洋铝株式会社 | Electrode foil for aluminum electrolytic capacitor and production method for same |
| CN108431916A (en) * | 2016-03-31 | 2018-08-21 | 日本贵弥功株式会社 | The manufacturing method of electrode foil, convoluted capacitor, the manufacturing method of electrode foil and convoluted capacitor |
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