CN116913694A - Aluminized foil, electrode for aluminum electrolytic capacitor, and method for producing aluminized foil - Google Patents
Aluminized foil, electrode for aluminum electrolytic capacitor, and method for producing aluminized foil Download PDFInfo
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- CN116913694A CN116913694A CN202310986558.0A CN202310986558A CN116913694A CN 116913694 A CN116913694 A CN 116913694A CN 202310986558 A CN202310986558 A CN 202310986558A CN 116913694 A CN116913694 A CN 116913694A
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- foil
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- 239000011888 foil Substances 0.000 title claims abstract description 479
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 335
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 333
- 238000004519 manufacturing process Methods 0.000 title claims description 126
- 239000003990 capacitor Substances 0.000 title claims description 75
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 395
- 239000000843 powder Substances 0.000 claims abstract description 71
- 229910000838 Al alloy Inorganic materials 0.000 claims abstract description 29
- 230000003647 oxidation Effects 0.000 claims description 225
- 238000007254 oxidation reaction Methods 0.000 claims description 225
- 238000000034 method Methods 0.000 claims description 140
- 238000007743 anodising Methods 0.000 claims description 99
- 230000036571 hydration Effects 0.000 claims description 56
- 238000006703 hydration reaction Methods 0.000 claims description 56
- 239000002245 particle Substances 0.000 claims description 15
- 239000011248 coating agent Substances 0.000 claims description 2
- 238000000576 coating method Methods 0.000 claims description 2
- 238000010030 laminating Methods 0.000 claims description 2
- 238000005452 bending Methods 0.000 description 39
- 101100421916 Arabidopsis thaliana SOT5 gene Proteins 0.000 description 29
- 101100421917 Arabidopsis thaliana SOT6 gene Proteins 0.000 description 25
- 230000000052 comparative effect Effects 0.000 description 20
- 239000007788 liquid Substances 0.000 description 17
- 238000010586 diagram Methods 0.000 description 16
- 239000000126 substance Substances 0.000 description 16
- 238000005336 cracking Methods 0.000 description 14
- 238000010438 heat treatment Methods 0.000 description 12
- 239000000463 material Substances 0.000 description 10
- 150000003839 salts Chemical class 0.000 description 10
- 238000004804 winding Methods 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 9
- 238000003825 pressing Methods 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 238000007739 conversion coating Methods 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 238000005269 aluminizing Methods 0.000 description 4
- 239000007888 film coating Substances 0.000 description 4
- 238000009501 film coating Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 3
- 239000004327 boric acid Substances 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 239000007784 solid electrolyte Substances 0.000 description 3
- 238000012795 verification Methods 0.000 description 3
- FLDCSPABIQBYKP-UHFFFAOYSA-N 5-chloro-1,2-dimethylbenzimidazole Chemical compound ClC1=CC=C2N(C)C(C)=NC2=C1 FLDCSPABIQBYKP-UHFFFAOYSA-N 0.000 description 2
- 239000001741 Ammonium adipate Substances 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 2
- 235000019293 ammonium adipate Nutrition 0.000 description 2
- 238000002048 anodisation reaction Methods 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
- 239000011651 chromium Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000002950 deficient Effects 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
- 229910052759 nickel Inorganic materials 0.000 description 2
- 235000012149 noodles Nutrition 0.000 description 2
- 238000004626 scanning electron microscopy Methods 0.000 description 2
- CXMXRPHRNRROMY-UHFFFAOYSA-N sebacic acid Chemical compound OC(=O)CCCCCCCCC(O)=O CXMXRPHRNRROMY-UHFFFAOYSA-N 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 2
- 230000000007 visual effect Effects 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
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000008280 blood Substances 0.000 description 1
- 210000004369 blood Anatomy 0.000 description 1
- 229910001593 boehmite Inorganic materials 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000004049 embossing Methods 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
- 238000005259 measurement Methods 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- QYHFIVBSNOWOCQ-UHFFFAOYSA-N selenic acid Chemical compound O[Se](O)(=O)=O QYHFIVBSNOWOCQ-UHFFFAOYSA-N 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-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, LIGHT-SENSITIVE OR TEMPERATURE-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, LIGHT-SENSITIVE OR TEMPERATURE-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, LIGHT-SENSITIVE OR TEMPERATURE-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, LIGHT-SENSITIVE OR TEMPERATURE-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
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
- Laminated Bodies (AREA)
Abstract
The present invention provides an aluminized foil (1) having: an aluminum foil (10) in which a first porous layer (3) of a sintered body of a powder (11) containing aluminum or an aluminum alloy is laminated on a first surface (2 a) of both surfaces of a foil-shaped base layer (2) containing aluminum or an aluminum alloy; and a first formation film (5) formed on the first porous layer (3). A plurality of cracks (7) extending in the Y direction at intervals of 30-150 μm in the X direction and having a length of 300 μm or more are provided on the surface of the first porous layer (3).
Description
The application date is2020, 04 and 30 daysApplication number is202080038627.X、
The invention is named'Aluminized foil, electrode for aluminum electrolytic capacitor, and method for producing aluminized foilDivision of application
Technical Field
The present invention relates to an aluminized foil obtained by chemical conversion of an aluminum foil having a porous layer containing a sintered body of a powder of aluminum or an aluminum alloy, 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 aluminized foil obtained by anodizing an aluminum foil having a porous layer of a sintered body of aluminum-containing powder is known. In such aluminized foil, there is a problem that if the aluminum foil is bent in an anodic oxidation step of forming a formed film by anodic oxidation of the aluminum foil, the aluminum foil breaks. In patent document 1, the surface of a sintered body is embossed so that the surface roughness of the sintered body falls within a predetermined range, and then an anodic oxidation step is performed to reduce breakage of aluminum foil.
Prior art literature
Patent literature
Patent document 1: international publication 2016/136804
Disclosure of Invention
Technical problem to be solved by the invention
The reason why the bending strength of the aluminum foil is lowered in the anodic oxidation step is that it is difficult to release stress from the aluminum foil as the formation film grows. That is, in the anodic oxidation step, the formation film grows on the surface of the porous layer of the sintered body containing the powder. Thus, adjacent powders are bonded by the formation film. In this state, when the aluminum foil is bent, the powder is firmly bonded to each other, so that the stress due to the deformation cannot be released from the aluminum foil. As a result, the bonding between the powders is locally broken. The fracture spreads to fracture the aluminum foil.
Here, even if anodic oxidation is performed on the aluminum foil having the surface of the porous layer subjected to the embossing, as the formation film grows, adjacent powders are bonded by the formation film. Therefore, even in the case of the technique of patent document 1, it is not easy to release stress caused by deformation from the aluminum foil, and it is difficult to sufficiently suppress the reduction in bending strength of the aluminum foil.
In view of the above problems, an object of the present invention is to provide an aluminized foil capable of preventing or suppressing breakage of an aluminum foil caused by bending when an aluminum foil having a porous layer containing a sintered body of powder is anodized. Also provided is a method for producing the aluminized foil.
Technical scheme for solving technical problems
In order to solve the above-described problems, the aluminized foil according to the present invention includes: an aluminum foil having a first porous layer of a sintered body of a powder containing aluminum or an aluminum alloy laminated on a first surface of both surfaces of a foil-shaped base layer containing aluminum or an aluminum alloy; and a first chemical conversion coating formed on the first porous layer, wherein a plurality of cracks extending in a first direction in an in-plane direction by a length of 300 μm or more are provided at intervals of 30 μm to 150 μm in a second direction orthogonal to the first direction in the in-plane direction on the surface of the first porous layer.
The aluminized foil of the present invention has cracks extending in a first direction in an in-plane direction over a length of 300 [ mu ] m on the surface of a first porous layer. And a plurality of cracks are provided at intervals of 30-150 μm in a second direction of the in-plane direction of the aluminized foil. In the aluminized foil having such a plurality of cracks, even when the aluminum foil to which the adjacent powder is bonded by the first formation film is bent due to the anodic oxidation of the aluminum foil, the stress due to the deformation can be released from the crack portion after the anodic oxidation is completed. This can prevent or suppress local cracking of the bond between the powders, and thus prevent or suppress the expansion of the cracking to fracture the aluminum foil.
In the present invention, it is preferable that the plurality of cracks each reach a boundary between the base layer and the first porous layer. By such arrangement, even when the aluminum foil is bent during the anodic oxidation, the stress due to the deformation is easily released from the aluminum foil.
In the present invention, the aluminum foil may have a longer dimension in the second direction than 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 of a sintered body containing aluminum or an aluminum alloy powder may be laminated on a second surface of the base layer opposite to the first surface, a second chemical conversion coating may be formed on the second porous layer, and a plurality of cracks extending in the in-plane direction may be provided on the surface of the second porous layer at the intervals. By providing this, even in the case where the aluminum foil has porous layers on both sides of the base layer, the stress generated in the anodized aluminum foil can be released.
The present invention may be an electrode for an aluminum electrolytic capacitor comprising the above aluminized foil.
The electrode for an aluminum electrolytic capacitor of the present invention has a plurality of cracks in the first porous layer. Therefore, when the aluminum foil is anodized to produce an electrode for an aluminum electrolytic capacitor, breakage of the aluminum foil can be prevented or suppressed even when the aluminum foil is bent. 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 the electrode has no cracks. Therefore, the capacitance 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 be wound in a roll shape having a spiral curve in the second direction. When an electrode for an aluminum electrolytic capacitor is formed by winding and aluminizing a foil, it is easy to wind the electrode in a second direction in which a plurality of cracks are aligned. Therefore, compared with the case where the aluminized foil does not have a crack, the aluminized foil having a crack can be wound in a shape close to a perfect circle. 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 aluminum electrolytic capacitor electrode having a roll shape in which the aluminum foil is wound in a spiral curve is used as the capacitor element, the aluminum electrolytic capacitor electrode having a longer dimension in the second direction can be stored when the capacitor element is stored in the exterior case than when the aluminum electrolytic capacitor electrode is not wound in a spiral curve. This increases the surface area of the electrode for the aluminum electrolytic capacitor, and thus the capacitance of the aluminum electrolytic capacitor can be increased. Further, by winding the aluminized foil into a spiral curve to form a roll shape, breakage of the aluminized foil at the bent portion can be prevented as compared with a case where the aluminized foil has the bent portion in the middle. Therefore, the windability of the aluminized foil can be improved.
Next, another aspect of the present invention is an aluminized foil comprising: an aluminum foil having a first porous layer of a sintered body of a powder containing aluminum or an aluminum alloy laminated on a first surface of both surfaces of a foil-shaped base layer containing aluminum or an aluminum alloy; and a first chemical conversion coating 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 a second direction orthogonal to the first direction in the in-plane direction, and the plurality of cracks reach 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 in an in-plane direction, on a surface of a first porous layer, separately in a second direction in the in-plane direction. And each crack reaches the boundary between the base layer and the first porous layer. In the aluminized foil having such a plurality of cracks, even if the aluminum foil to which the adjacent powder is bonded by the first formation film is bent due to the anodic oxidation of the aluminum foil, the stress due to the deformation can be released from the crack portion after the anodic oxidation is completed. This can prevent or suppress local cracking of the bond between the powders, and thus prevent or suppress the expansion of the cracking to fracture the aluminum foil.
The present invention may be an electrode for an aluminum electrolytic capacitor comprising the above aluminized foil.
The electrode for an aluminum electrolytic capacitor of the present invention has a plurality of cracks in the first porous layer. Therefore, when the aluminum foil is anodized to produce an electrode for an aluminum electrolytic capacitor, breakage of the aluminum foil can be prevented or suppressed even when the aluminum foil is bent. 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 the electrode has no cracks. Therefore, the capacitance 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 be wound in a roll shape having a spiral curve in the second direction. When an electrode for an aluminum electrolytic capacitor is formed by winding and aluminizing a foil, it is easy to wind the electrode in a second direction in which a plurality of cracks are aligned. Therefore, compared with the case where the aluminized foil does not have a crack, the aluminized foil having a crack can be wound in a shape close to a perfect circle. 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 bending portion in the middle. Here, if the aluminum electrolytic capacitor electrode having a roll shape in which the aluminum foil is wound in a spiral shape is used as the capacitor element, when the capacitor element is housed in the exterior case, the aluminum electrolytic capacitor electrode having a longer dimension in the second direction can be housed than in the case where the aluminum electrolytic capacitor electrode is not wound in a spiral shape. This increases the surface area of the electrode for the aluminum electrolytic capacitor, and thus the capacitance of the aluminum electrolytic capacitor can be increased. Further, by winding the aluminized foil in a spiral curve to form a roll shape, breakage of the aluminized foil at the bent portion can be prevented as compared with a case where the aluminized foil has the bent portion in the middle. Therefore, the windability of the aluminized foil can be improved.
Next, the method for producing an aluminized foil according to the present invention is characterized by: the method comprises a formation step of forming a first formation film on an aluminum foil, wherein the aluminum foil comprises a first porous layer formed by laminating a sintered body of a powder containing aluminum or an aluminum alloy on a first surface of a foil-shaped base layer containing aluminum or an aluminum alloy, the formation step comprises an anodic oxidation step of anodizing the aluminum foil, a crack formation treatment is performed in the formation step, stress is generated in the aluminum foil, 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, and a post-crack formation anodic oxidation treatment is performed in the anodic oxidation step, wherein the post-crack formation anodic oxidation treatment is a treatment of anodizing the aluminum foil after the crack formation treatment.
According to the present invention, the aluminum foil is subjected to stress in the forming step, whereby a plurality of cracks extending in the first direction are provided on the surface of the first porous layer so as to be separated in the second direction. After forming the crack, the aluminum foil is anodized. Here, by forming the crack in the first porous layer in the middle of the formation step, even if the first formation film grows due to the subsequent anodic oxidation, it is possible to suppress the crack from closing due to the first formation film. Thus, an aluminized foil having a plurality of cracks can be obtained. Therefore, even when the aluminum foil to which the adjacent powder is bonded by the first formation film is bent with the growth of the first formation film, the stress due to the deformation can be released from the crack. This can prevent or suppress local cracking of the bonding between the powders, and thus can prevent or suppress local expansion of the cracking to fracture the aluminum foil. Further, since the aluminum foil is anodized after the formation of the crack, the first formation film can be formed on the first porous layer after the crack is generated. Thus, the aluminum new surface (surface of bare metal aluminum) exposed on the surface of the first porous layer due to the formation of cracks can be covered with the reformed first chemical conversion coating. Therefore, it is possible to reduce the leakage current of the aluminum foil or the electrode for the aluminum electrolytic capacitor in the anodic oxidation caused by the crack, and to prevent or suppress the breakage.
In the present invention, in the crack formation process, a plurality of cracks extending in the first direction by 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 cracks, even when the first formation film grows due to anodic oxidation, it is possible to prevent or suppress the cracks from closing due to the first formation film.
In the present invention, in the crack formation treatment, it is desirable that each crack reach a boundary between the base layer and the first porous layer. By such arrangement, even if the aluminum foil is bent during the anodic oxidation, the stress due to the deformation is easily released from the crack due to the crack depth.
Further, the thickness of the first chemical film grown until the voltage at the time of the anodic oxidation reaches a predetermined anodic oxidation voltage can be estimated. Therefore, if the anodic oxidation treatment before the crack formation is performed to the aluminum foil until the predetermined anodic oxidation voltage is reached, it is possible to prevent the first formation film from becoming too thick at the time point when the crack formation treatment is performed, and the aluminum foil from becoming too hard. This can prevent the aluminum foil from breaking when the aluminum foil is subjected to stress. In addition, when the aluminum foil is subjected to stress, 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 conversion coating is increased to reach the target coating withstand voltage, the decrease in bending strength can be suppressed.
The predetermined anodic oxidation voltage may be 400V or less. The term "until the predetermined anodic oxidation voltage is reached" includes a time point when the predetermined anodic oxidation voltage is reached. By doing so, the first formation film does not become excessively thick at the time point of forming the crack, and the aluminum foil does not become excessively hard, as compared with the case where the crack formation treatment is performed after the voltage at the time of anodic oxidation reaches the predetermined anodic oxidation voltage. Thus, when stress is generated in the aluminum foil, the aluminum foil is not easily broken. In addition, if the crack formation treatment is performed until the voltage at the time of anodic oxidation reaches a predetermined anodic oxidation voltage, the first formation film does not become excessively thick, and the aluminum foil does not become excessively hard, so that the stress is generated in the aluminum foil, whereby a plurality of cracks can be uniformly provided on the surface of the first porous layer. Here, if a plurality of cracks can be uniformly provided on the surface of the first porous layer, even when the first formation film is formed to be thick due to the anodic oxidation after the voltage at the time of the anodic oxidation reaches the predetermined anodic oxidation voltage, the decrease in bending strength can be suppressed.
In the present invention, in the crack formation process, the first crack formation roller extending in the first direction may be brought into contact with a second surface opposite to the first surface of the two surfaces of the aluminum foil, and the aluminum foil and the first crack formation roller may be moved relatively in the second direction. By providing the first crack forming roller in this manner, the aluminum foil is stressed, and cracks can be formed 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 among the plurality of rollers, a roller having a smaller diameter than the other rollers may be arranged as the first crack forming roller. By using a roller having a small diameter as the first crack forming roller, the aluminum foil is easily stressed by the first crack forming roller.
In the present invention, a second porous layer of 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, and a second formation film may be formed on the second porous layer in the formation step, and in the crack formation process, a second crack formation roller extending in the first direction may be brought into contact with the first surface in the second direction at a position different from the first crack formation roller, and the aluminum foil and the second crack formation roller may be relatively moved in the second direction. By providing this, 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 folded during the anodic oxidation, the stress due to the deformation can be released from the aluminum foil. Therefore, breakage of the aluminum foil can be prevented or suppressed.
In the present invention, the chemical conversion step may include a hydration step of forming a hydrated film on the aluminum foil before the anodic oxidation step, wherein the anodic oxidation step is performed to anodize the aluminum foil on which the hydrated film is formed, and the crack formation treatment may be performed in the middle of the hydration step. By this arrangement, in the hydration step, a hydrated film is formed on the surface of the first porous layer. Further, cracks were provided in the first porous layer during the hydration step. Thus, the aluminum new surface is exposed to the surface of the first porous layer due to the crack by the crack formation treatment. That is, powder having no hydrated film formed on the surface is exposed on the fracture surface of the first porous layer formed by the fracture. Thereafter, in the hydration step continued after the crack formation treatment, a hydrated film is formed on the aluminum fresh noodle. The hydrated film coating the aluminum fresh surface prevents or inhibits the powder on both sides of the crack from being bonded to each other by the first formation film in the anodic oxidation step. Therefore, if the crack formation treatment is performed during the hydration step, it is possible to prevent or suppress the crack closure due to the first formation film when the first formation film grows in the crack formation treatment and the anodic oxidation step performed after the hydration step.
In the present invention, the chemical conversion step may include a hydration step of forming a hydrated film on the aluminum foil before the anodic oxidation step, wherein the anodic oxidation step is performed to anodize the aluminum foil on which the hydrated film is formed, and the crack formation treatment may be performed after the hydration step. By this arrangement, in the hydration step, a hydrated film is formed on the surface of the first porous layer. The hydrated film serves as a barrier to the bonding of the powders together by the first formation film in the anodic oxidation step, and prevents or inhibits the bonding of the powders together. Therefore, by providing the crack formation treatment after the hydration step performed during the formation step, the phenomenon that the cracks formed in the first porous layer are closed by the first formation film is easily suppressed.
In the present invention, it is desirable to include a rehydration treatment for forming a hydrated film on the aluminum foil after the crack formation treatment. In this way, in the rehydration treatment performed after the crack formation treatment, a hydrated film is formed on the aluminum fresh surface where the surface of the first porous layer is exposed due to the formation of the crack. The hydrated film coating the aluminum-coated fresh surface prevents or inhibits the powder on both sides of the crack from being bonded to each other by the first formation film in the anodic oxidation step. Therefore, by performing the rehydration treatment after the crack formation treatment, it is possible to suppress the cracks from closing due to the first formation film when the first formation film grows thereafter.
ADVANTAGEOUS EFFECTS OF INVENTION
The aluminized foil of the present invention has cracks extending in a first direction in an in-plane direction over a length of 300 [ mu ] m on the surface of a first porous layer. And a plurality of cracks are provided at intervals of 30-150 μm in a second direction of the in-plane direction of the aluminized foil. In the aluminized foil having such a plurality of cracks, even when the aluminum foil is bent when the aluminum foil is anodized, the stress due to the deformation can be released from the crack portion after the completion of the anodization. This can prevent or suppress local cracking of the bonding between the powders, and thus can prevent or suppress breakage of the aluminum foil.
In another embodiment of the present invention, the aluminized foil has a plurality of cracks extending in the first direction in the in-plane direction, the cracks being provided on the surface of the first porous layer so as to be separated in the second direction in the in-plane direction. And each crack reaches the boundary between the base layer and the first porous layer. In the aluminized foil having such a plurality of cracks, even when the aluminum foil is bent when the aluminum foil is anodized, the stress due to the deformation can be released from the crack portion after the completion of the anodization. This can prevent or suppress local cracking of the bonding between the powders, and thus can prevent or suppress breakage of the aluminum foil.
The method for producing an aluminized foil according to the present invention includes a formation step of forming a first formation film on an aluminum foil laminated with a first porous layer, and the formation step includes an anodic oxidation step of anodizing the aluminum foil. In the formation step, cracks are formed in the first porous layer, and in the anodic oxidation step, anodic oxidation is performed on the aluminum foil after the formation of the cracks. In this way, by forming cracks in the first porous layer during the formation step, an aluminized foil having a plurality of cracks can be obtained. Therefore, the stress due to the deformation of the aluminized foil can be released from the crack. This can prevent or suppress local cracking of the bonding between the powders, and thus can prevent or suppress local expansion of the cracking to fracture the aluminum foil. In addition, by the anodic oxidation treatment after the crack is provided, the first formation film can be formed on the first porous layer after the crack is generated. Thus, the surface of the metallic aluminum exposed by the formation of cracks can be covered with the reformed chemical film. Therefore, it is possible to reduce the leakage current of the aluminum foil or the electrode for the aluminum electrolytic capacitor in anodic oxidation due to the crack, and to prevent or suppress the breakage.
Drawings
Fig. 1 is a photograph of the surface of aluminized foil taken at an enlarged scale using a scanning electron microscope.
Fig. 2 is a photograph of a cross section of an aluminized foil cut in the longitudinal direction by scanning electron microscopy.
FIG. 3 is an explanatory diagram of aluminizing into a foil.
FIG. 4 is an explanatory diagram of a method for measuring the intervals between cracks provided on the surface of an aluminized foil.
Fig. 5 is a schematic view of an electrode for an aluminum electrolytic capacitor in a roll shape.
Fig. 6 is an explanatory diagram of an aluminum foil as a base material of aluminized foil.
FIG. 7 is a flow chart showing a first method of manufacturing aluminized foil.
FIG. 8 is a flow chart showing a second method of manufacturing aluminized foil.
FIG. 9 is a flow chart showing a third method of manufacturing aluminized foil.
FIG. 10 is a flow chart showing a fourth method of manufacturing aluminized foil.
FIG. 11 is a flow chart showing a fifth method of manufacturing aluminized foil.
Fig. 12 is an explanatory diagram of the crack formation process.
Fig. 13 is a table illustrating the timing of performing the crack formation treatment in the aluminized foil manufacturing methods of examples 1 to 5.
Fig. 14 is an explanatory diagram of the timing of performing the crack formation treatment in the aluminized foil manufacturing method of examples 1 to 5.
Fig. 15 is a table showing the intervals of cracks, bending strength, tensile strength, electrostatic capacity, and film withstand voltage of the aluminized foil in examples 1 to 5 and comparative examples 1 and 2.
FIG. 16 is a photograph of the surface of aluminized foil produced by the production method of example 5 taken at an enlarged scale using a scanning electron microscope.
FIG. 17 is a photograph of the surface of an aluminized foil of comparative example 1 taken at an enlarged scale using a scanning electron microscope.
FIG. 18 is a photograph of a cross section of an aluminized foil of comparative example 1 taken at an enlarged scale using a scanning electron microscope.
Fig. 19 is a table illustrating the timing of performing the crack formation treatment in the aluminized foil manufacturing methods of examples 6 to 8.
Fig. 20 is an explanatory diagram of the timing of performing the crack formation treatment in the aluminized foil manufacturing method of examples 6 to 8.
FIG. 21 is a table showing the crack intervals, bending strength, tensile strength, capacitance, and film withstand voltage of the aluminized foil in examples 6 to 8.
Fig. 22 is a table illustrating the timing of performing the crack formation treatment in the aluminized foil manufacturing method of examples 9 to 11.
Fig. 23 is an explanatory diagram of the timing of performing the crack formation treatment in the aluminized foil manufacturing method of examples 9 to 11.
FIG. 24 is a table showing the crack intervals, bending strength, tensile strength, capacitance, and film withstand voltage of the aluminized foil in examples 9 to 11.
FIG. 25 is a flow chart showing a sixth method of manufacturing aluminized foil.
FIG. 26 is a flow chart showing a seventh method of manufacturing aluminized foil.
Detailed Description
Hereinafter, embodiments of an aluminized foil and a method for producing an aluminized foil according to the present invention will be described 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 embodiment may be appropriately combined. The aluminized foil of this example was used as an electrode for an aluminum electrolytic capacitor. Hereinafter, an aluminum electrolytic capacitor using an aluminized foil as an electrode (anode foil) for an aluminum electrolytic capacitor will be described, and then, an aluminized foil and a method for producing the aluminized foil will be described. In the present specification, the symbols "to" when the numerical range is represented by the lower limit value and the upper limit value "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 each composed of an aluminized foil (electrode for 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 electrolyte is housed in the exterior case, and the case is sealed with a sealing body.
In addition, in the case of using a solid electrolyte instead of the electrolyte, after forming a solid electrolyte layer on the surface of an anode foil composed of aluminized foil (electrode for aluminum electrolytic capacitor), a cathode layer is formed on the surface of the solid electrolyte layer, and then exterior is carried out 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.
(aluminized foil)
FIG. 1 is a photograph taken at an enlarged scale of the surface of an aluminized foil of the present invention using a scanning electron microscope. Fig. 2 is a photograph of a cross section of the aluminized foil of fig. 1 cut along the longitudinal direction by scanning electron microscopy. Fig. 3 is an explanatory diagram showing a relationship between powder constituting the porous layer and the formation film in the aluminized foil. Fig. 3 schematically shows a base layer, powder, and a formation film constituting an aluminized foil. FIG. 4 is an explanatory diagram of a method for measuring the intervals between cracks provided on the surface of an aluminized foil.
The aluminized foil 1 is produced by anodizing an aluminum foil including a base layer 2 and porous layers (a first porous layer 3 and a second porous layer 4). The aluminized foil 1 (electrode for aluminum electrolytic capacitor) is long.
As shown in fig. 2, aluminized foil 1 has: a foil-shaped base layer 2 comprising 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. The first porous layer 3 and the second porous layer 4 each contain a sintered body of a powder of aluminum or an aluminum alloy. The aluminized foil 1 has a first formation film 5 formed on the first porous layer 3 and a second formation film 6 formed on the second porous layer 4.
In the following description, 3 directions orthogonal to each other are referred to as an X direction, a Y direction, and a Z direction, and the X direction is referred to as a longitudinal direction of the aluminized foil 1. The Y direction is taken as the short side direction of the aluminized foil 1. The Z direction is a direction in which the first porous layer 3 and the second porous layer 4 are laminated to the 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 may be used. The aluminum alloy is obtained by adding at least 1 metal element selected from the group consisting of silicon, iron, copper, manganese, magnesium, chromium, zinc, titanium, vanadium, gallium, nickel, and boron to aluminum, or aluminum containing any one of these elements as an unavoidable impurity element. The thickness dimension T1 of the base layer 2 is usually 10 μm or more, preferably 20 μm or more, and is usually 100 μm or less, preferably 50 μm or less.
The first porous layer 3 and the second porous layer 4 are sintered bodies containing powders of at least 1 selected from aluminum and aluminum alloys. As shown in fig. 3, the first porous layer 3 and the second porous layer 4 have a three-dimensional mesh structure by maintaining voids with each other by the powder and sintering the connection. The first formation film 5 and the second formation film 6 are formed on the surface of the three-dimensional mesh structure of the powder 11. Here, the first porous layer 3 and the second porous layer 4 have a three-dimensional mesh structure, and thus have a large surface area. Therefore, when the aluminized foil 1 is used 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 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 generally the same or substantially the same. However, the thickness of the first porous layer 3 may be different from the thickness of the second porous layer 4. In this case, the thickness of the first porous layer 3 may be larger than the thickness of the second porous layer 4, or the thickness of the second porous layer 4 may be larger than the thickness of the first porous layer 3. In this example, the thickness dimension T2 of the first porous layer 3 and the thickness dimension T3 of the second porous layer 4 are each 10 μm to 500 μm. The thickness dimension T2 of the first porous layer 3 and the thickness dimension T3 of the second porous layer 4 are preferably 50 μm to 200 μm. That is, the thickness of the porous layer obtained by adding the thickness of the first porous layer 3 and the thickness of the second porous layer 4 is 20 μm or more and 1000 μm or less. The thickness of the porous layer obtained by adding the thickness of the first porous layer 3 and the thickness of the second porous layer 4 is preferably 100 μm or more and 400 μm or more. The average particle diameter K of the powder 11 constituting the first porous layer 3 and the second porous layer 4 is 1 μm or more and 20 μm or less.
The average particle diameter K of the powder 11 is obtained by observing the cross section of the first porous layer 3 or the second porous layer 4 with a scanning electron microscope. Specifically, when the sintered powder 11 is observed, the powder 11 is in a state of being partially melted or in a state of being connected to each other, but a portion having a slightly rounded shape may be regarded as particles approximately. Therefore, in the cross-sectional view, the maximum diameter of each of the particles having a slightly 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 the particle diameters is defined as the average particle diameter K of the sintered powder 11.
As shown in fig. 1, a plurality of cracks 7 extending in the in-plane direction by a length of 300 μm or more in the Y direction (first direction) are provided on the surface of the first porous layer 3 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 the first porous layer 3 reaches the boundary between the base layer 2 and the first porous layer 3. Also, on the surface of the second porous layer 4, a plurality of cracks 7 extending in the Y direction by a length of 300 μm or more are provided at intervals of 30 μm to 150 μm in the X direction orthogonal to the Y direction. Each crack 7 provided in the second porous layer 4 reaches the boundary between the base layer 2 and the second porous layer 4.
The lengths and intervals of the cracks 7 of the first porous layer 3 and the second porous layer 4 were measured by observation with a scanning electron microscope. More specifically, as shown in fig. 4, the reference line 8 is drawn in the X direction near the center of the visual field when viewed in the visual field in the range of 500 μm or more in the X direction and 1000 μm or more in the Y direction of the aluminized foil 1. Then, the number of intersections 9 with the crack 7 having a length of 300 μm or more is counted. Then, the length of the reference line 8 converted from the scale is divided by the number of intersections 9, and the interval between the cracks 7 having a length of 300 μm or more is calculated. The average of the measurement and calculation performed over 3 fields of view is defined as the interval between adjacent cracks 7.
(effect of aluminized foil)
The aluminized foil 1 of this example had cracks 7 extending in the Y direction over a length of 300 μm on the surface of the porous layers (the first porous layer 3 and the second porous layer 4). The number of cracks 7 is set at intervals of 30 μm to 150 μm in the X direction of the aluminized foil 1. In the aluminized foil 1 having such a plurality of cracks 7, even when the aluminum foil to which the adjacent powder 11 is bonded by the formation films (the first formation film 5 and the second formation film) is bent due to 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 local cracking of the bond between the powders 11, and thus prevent or suppress the expansion of the cracking to fracture the aluminum foil.
In addition, the plurality of cracks 7 each reach the boundary between the base layer 2 and the porous layers (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 aluminized 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 aluminum electrolytic capacitor is larger than that in the case where the crack 7 is not provided in the porous layers (the first porous layer 3 and the second porous layer 4). Therefore, if the aluminized foil is used as an electrode for an aluminum electrolytic capacitor, the capacitance can be increased.
In addition, when the aluminum foil 1 is wound to form a roll-shaped electrode for an aluminum electrolytic capacitor, it is easy to wind the aluminum foil 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, 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 an aluminized foil 1 is wound in a spiral curve in a second direction, and shows a side view of the aluminized foil 1 as seen from the first direction. In FIG. 5, aluminized foil 1 was wound around the outer peripheral surface of 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 (the electrode 15 for aluminum electrolytic capacitor) is not bent in the middle, and can be wound in a shape close to a perfect circle. That is, when an aluminized foil having no crack 7 is wound, a plurality of bent portions are formed in the middle of the aluminized foil. In contrast, when the aluminized foil 1 having the plurality of cracks 7 is wound, the roll shape wound in the X direction can be formed without having a bent portion in the middle.
Here, if the roll-shaped aluminum electrolytic capacitor electrode 15 obtained by winding the aluminized foil 1 in a nearly round shape is used as the capacitor element, the aluminum electrolytic capacitor electrode 15 having a longer dimension in the X direction can be stored when the capacitor element is stored in the exterior case than when the aluminum electrolytic capacitor electrode is not wound in a nearly round state. This increases the surface area of the electrode 15 for an aluminum electrolytic capacitor, thereby increasing the capacitance of the aluminum electrolytic capacitor. In addition, if the aluminized foil 1 is wound in a spiral curve to form a roll shape, breakage of the aluminized foil 1 occurring in the bent portion can be prevented as compared with the case where the aluminized foil 1 has the bent portion in the middle. Therefore, the windability of the aluminized foil 1 can be improved.
(method for producing aluminized foil)
Fig. 6 is an explanatory diagram of an aluminum foil as a base material of aluminized foil 1. In fig. 6, an aluminum foil is schematically shown. Fig. 7 is a flow chart showing a first manufacturing method of aluminized foil 1. Fig. 8 is a flow chart showing a second manufacturing method of aluminized foil 1. Fig. 9 is a flow chart showing a third manufacturing method of aluminized foil 1. Fig. 10 is a flow chart showing a fourth manufacturing method of aluminized foil 1. Fig. 11 is a flowchart showing a fifth manufacturing method of aluminized foil 1.
Next, a method for producing 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 manufacture of aluminized foil 1. The aluminum foil 10 has a foil-like base layer 2 comprising aluminum or an aluminum alloy. A first porous layer 3 of a sintered body of powder 11 containing aluminum or an aluminum alloy is laminated on a first surface 2a of the base layer 2, and a second porous layer 4 of a sintered body of powder 11 containing aluminum or an aluminum alloy is laminated on a second surface 2b of the base layer 2. In this example, the powder 11 of the first porous layer 3 and the powder 11 of the second porous layer 4 are composed of the same metal powder 11. In addition, the thickness of the first porous layer 3 is the same or substantially the same as the thickness of the second porous layer 4.
As shown in fig. 7 to 11, the method for producing the aluminized foil 1 includes: a formation step ST1 of forming a first formation film 5 on the first porous layer 3 of the aluminum foil 10 (substrate) and forming a second formation film 6 on the second porous layer 4. The formation step ST1 sequentially includes: 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 on which the hydrated film is formed. In this example, in the anodic oxidation step ST3, a heat treatment ST31 is performed to heat the aluminum foil 10 and expose defective portions in the middle of the constant voltage formation treatment step. That is, as shown in fig. 7 to 11, in the anodizing step ST3, an anodizing treatment (not shown) is performed before and after the heat treatment ST31. In this specification, the same applies to the case where the description is made using other flowcharts.
In the formation step ST1, a crack formation process ST11 is performed, and in the crack formation process ST11, 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 more detail, the method for producing the aluminized foil 1 of the present example is described in which, in the anodizing step ST3, a crack formation post-anodizing treatment ST3A is performed in which the aluminum foil 10 is anodized after the crack formation treatment ST11. In the drawings and the following description, the post-crack-formation anodizing treatment ST3A is simply referred to as post-anodizing treatment ST3A.
Here, in fig. 7 and 11, crack formation processing ST11 is performed in the middle of the formation step ST1 and in the middle of the hydration processing ST 2. That is, in the hydration step ST2, hydration treatment (not shown) is performed before and after the crack formation treatment ST11.
In fig. 9 and 10, a crack formation process ST11 is performed in the middle of the formation step ST1 and in the middle of the anodic oxidation step ST 3. That is, in the anodic oxidation step ST3, before the crack formation process ST11, the anodic oxidation process ST3B is performed before the crack formation in which the aluminum foil 10 is anodized until the voltage at the time of anodic oxidation reaches a predetermined anodic oxidation voltage. In the drawings and the following description, the pre-crack formation anodic oxidation process ST3B is simply referred to as a pre-anodic oxidation process ST3B. That is, when the crack formation process ST11 is performed in the middle of the anodic oxidation process ST3, the pre-anodic oxidation process ST3B, the crack formation process ST11, and the post-anodic oxidation process ST3A are sequentially performed in the anodic oxidation process 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 can be used. The rehydration process ST21 described later may be performed in the same manner.
In the anodizing step ST3, the aluminum foil 10 is immersed in the chemical conversion treatment liquid, and the voltage at the time of anodizing (the voltage output from the power supply) is brought to a predetermined anodizing voltage. Thereby, the formation films (the first formation film 5 and the second formation film 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 to be between 5 and 1000V. Of course, the anodic oxidation treatment (post anodic oxidation treatment ST3A and pre anodic oxidation treatment ST 3B) performed in the anodic oxidation 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 heated by being placed in a heat treatment furnace, for example. 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 air atmosphere, an inert gas atmosphere, and a steam 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 formation films (the first formation film 5 and the second formation film 6) or between the hydration step ST2 and the anodic oxidation step ST 3. At this time, in the anodic oxidation step ST3 (post anodic oxidation step ST 3A) after the crack formation step ST11, the aluminum foil 10 after the crack formation is anodized.
Alternatively, in the method for producing the aluminized foil 1 of the present example, in the anodizing step ST3, the crack formation treatment ST11 is performed before the voltage at the time of the anodizing reaches the final anodizing voltage as a final target. At this time, since the crack formation process ST11 is performed in the middle of the anodic oxidation process ST3, the pre-anodic oxidation process ST3B and the post-anodic oxidation process ST3A are performed before and after the formation of the crack. In the post-anodizing treatment ST3A, the aluminum foil 10 is anodized to an anodic oxidation voltage higher than the predetermined anodic oxidation voltage achieved in the preceding anodizing treatment ST 3B.
The predetermined anodic oxidation voltage is usually 400V or less. The predetermined anodic oxidation voltage is preferably 300V or less, more preferably 250V or less. In this example, in the anodizing step ST3, the aluminum foil 10 is anodized until the anodic oxidation voltage reaches the upper limit value, and thereafter, a crack formation process ST11 is performed. Thus, the aluminum foil 10 can be stressed at the timing when the formation film does not become too thick and the aluminum foil 10 does not become too hard. As a result, when the aluminum foil 10 is stressed, the fracture of the aluminum foil 10 can be suppressed, and a plurality of cracks can be uniformly provided on the surface of the porous layer. Here, the crack formation process ST11 may be performed before the formation of the formation film as long as it is in the middle of the formation step ST1, and therefore, the lower limit of the predetermined anodic oxidation voltage is not particularly limited. Therefore, the lower limit of the predetermined anodic oxidation voltage is usually 0V or more. The lower limit of the predetermined anodic oxidation voltage is preferably 10V or more, more preferably 50V or more. In the anodizing step ST3, the final anodizing voltage, which is the final target of the voltage at the time of anodizing, may be appropriately set according to the properties of the target aluminized foil 1. Therefore, the final anodic oxidation voltage is not particularly limited, and may be set to 1000V or less, for example.
In the anodizing step ST3, the aluminum foil 10 may be anodized by other known methods.
In the formation step ST1, at the end of the anodic oxidation step ST3, the aluminum foil 10 after formation, that is, the aluminized foil 1, is wound around a winding roller to form a roll.
Specific examples of the method for producing the aluminized foil 1 include the following first to fifth production methods in which the timing of performing the crack formation treatment ST11 is different.
As shown in fig. 7, the first production method of the aluminized foil 1 carries out a crack formation process ST11 in the middle of the hydration step ST 2. In the anodic oxidation step ST3 performed after the hydration step ST2, a post anodic oxidation treatment ST3A is performed.
As shown in fig. 8, in the second production method of the aluminized foil 1, a crack formation process ST11 is performed between the hydration step ST2 and the anodic oxidation step ST 3. In the anodic oxidation step ST3 performed after the crack formation process ST11, a post anodic oxidation process ST3A is performed.
As shown in fig. 9, in the third production method of the aluminized foil 1, a crack formation process ST11 is performed in the middle of the anodic oxidation step ST 3. Specifically, in the anodizing step ST3, a pre-anodizing treatment ST3B is performed in which the aluminum foil 10 is anodized until a predetermined anodizing voltage is reached, a crack formation treatment ST11 is performed after the pre-anodizing treatment ST3B, and a post-anodizing treatment ST3A is performed after the crack formation treatment ST11.
In the fourth production method of the aluminized foil 1, as shown in fig. 10, a crack formation process ST11 is performed in the middle of the anodic oxidation step ST3, as in the third production method. Specifically, in the anodizing step ST3, a pre-anodizing treatment ST3B is performed in which the aluminum foil 10 is anodized until a predetermined anodizing voltage is reached, and a crack formation treatment ST11 is performed after the pre-anodizing treatment ST 3B. Then, after the crack formation process ST11, a rehydration process ST21 is performed to form a hydrated film on the aluminum foil 10, and after the rehydration process ST21, a post-anodic oxidation process ST3A is performed. That is, in the fourth production method of the aluminized foil 1, the crack formation process ST11 and the rehydration process ST21 are continuously performed in the middle of the anodic oxidation process ST 3.
As shown in fig. 11, a fifth production method of aluminized foil 1 is to perform crack formation treatment ST11 in the middle of hydration step ST 2. Then, crack formation process ST11 is performed in the middle of anodic oxidation step ST 3. Specifically, in the hydration step ST2, the crack formation process ST11 is performed, and the hydration process is performed before and after the crack formation process ST11. In the anodizing step ST3, a pre-anodizing treatment ST3B is performed in which the aluminum foil 10 is anodized until a predetermined anodizing voltage is reached, 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 ST21.
Next, a specific method of stressing the aluminum foil 10 in the crack formation process ST11 is exemplified. 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 caused to travel along a plurality of rollers 21 aligned in the X direction.
The rotation axes of the plurality of rollers 21 each extend in the Y direction. Among the plurality of rollers 21 arranged in the X direction, rollers 21 having a smaller diameter than the other rollers 21 are arranged. Among these small diameter rolls 21, the roll 21 contacting the second surface 2b of the traveling aluminum foil 10 is disposed as a first crack forming roll 21 (1), and the first crack forming roll 21 (1) is a roll for stressing the aluminum foil 10 and causing the first porous layer 3 to generate cracks 7. Among these small diameter rolls 21, the roll 21 contacting the first surface 2a of the traveling aluminum foil 10 is disposed as a second crack forming roll 21 (2), and the second crack forming roll 21 (2) is a roll for stressing the aluminum foil 10 and causing the second porous layer 4 to generate cracks 7. The diameter M of the first crack forming roller 21 (1) and the second crack forming roller 21 (2) is 5mm to 60mm. In this example, the case where the diameter dimension M of the first crack forming roller 21 (1) and the diameter dimension M of the second crack forming roller 21 (2) are the same is illustrated, but the diameter dimensions M may be different.
In this example, the first crack forming roller 21 (1) and the second crack forming roller 21 (2) are made of metal. The first crack forming roller 21 (1) and the second crack forming roller 21 (2) are pressed by pressing rollers 23, respectively. The surface of each pressing roller 23 is covered with an elastic member such as rubber. It is desirable that the diameter of each pressing roller 23 is larger than the diameter of the first crack forming roller 21 (1) and the diameter of the second crack forming roller 21 (2).
When the aluminum foil 10 travels between the first crack forming 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 the first porous layer 3. When the aluminum foil 10 travels between the second crack forming 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 the second porous layer 4.
The wrap angle of the first crack forming roller 21 (1) when the aluminum foil 10 travels between the first crack forming roller 21 (1) and the pressing roller 23 is usually from-180 ° to 180 °, preferably from-45 ° to 45 °. The wrap angle of the second crack forming roller 21 (2) when the aluminum foil 10 travels between the second crack forming roller 21 (2) and the pressing roller 23 is usually from-180 ° to 180 °, preferably from-45 ° to 45 °. Further, it is more preferable that the wrap angle of the first crack forming roller 21 (1) and the second crack forming roller 21 (2) be 0 ° or more. Therefore, the wrap angles of the first crack forming roller 21 (1) and the second crack forming roller 21 (2) are 0 ° to 180 °, preferably 0 ° to 45 °. Here, when the wrap angle of the first crack forming roller 21 (1) is set to the above range, the first crack forming roller 21 (1) is brought into contact with the second surface 2b of the aluminum foil 10, thereby facilitating formation of the desired crack 7 in the first porous layer 3. When the wrap angle of the second crack forming roller 21 (2) is set to the above range, a desired crack 7 is 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.
The plurality of rollers 21 may have a plurality of first crack forming rollers 21 (1). In the case of having a plurality of first crack forming rollers 21 (1), it is desirable to have the same number of second crack forming rollers 21 (2) as the first crack forming rollers 21 (1) among the plurality of rollers 21. 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.
(effects of action)
In the method for producing the aluminized foil 1 of the present example, stress is applied to the aluminum foil 10 in the formation step ST1, whereby a plurality of cracks 7 extending in the Y direction are provided on the surface 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, after the crack 7 is formed, a post-anodizing treatment ST3A is performed to anodize the aluminum foil 10. Here, by forming the crack 7 in the porous layers (the first porous layer 3 and the second porous layer 4) in the middle of the formation step ST1, even when the formation films (the first formation film 5 and the second formation film 6) grow due to the subsequent anodic oxidation, it is possible to suppress the phenomenon that the crack 7 is closed due to the formation films (the first formation film 5 and the second formation film 6). Thus, the aluminized foil 1 having a plurality of cracks 7 can be obtained. Therefore, even when the aluminum foil 10 bonded by the adjacent powder 11 through the formation films (the first formation film 5 and the second formation film 6) is bent with the growth of the formation films (the first formation film 5 and the second formation film 6), the stress due to the deformation can be released from the crack 7. This can prevent or suppress local cracking of the bonding between the powders 11, and thus can prevent or suppress local expansion of cracking to fracture the aluminum foil 10. Further, by performing anodic oxidation on the aluminum foil 10 after the formation of the crack 7, the formation films (the first formation film 5 and the second formation film 6) can be formed again on the porous layers (the first porous layer 3 and the second porous layer 4) after the formation of the crack 7. Thus, the aluminum new surface (surface of bare metal aluminum) exposed on the surface of the porous layer (first porous layer 3 and second porous layer 4) due to the formation of the crack 7 can be covered with the reformed formation films (first formation film 5 and second formation film 6). Accordingly, it is possible to reduce the leakage current of the aluminum foil 10 or the electrode for an aluminum electrolytic capacitor in anodic oxidation due to the crack 7 and prevent or suppress breakage.
In the formation step ST1, the thickness of the grown formation films (the first formation film 5 and the second formation film 6) until the voltage output from the power supply reaches the predetermined anodic oxidation voltage can be estimated. Therefore, the thickness of the formation films (the first formation film 5 and the second formation film 6) can be controlled according to the voltage output from the power supply at the time of anodic oxidation. Therefore, if the pre-anodizing treatment ST3B is performed to anodize the aluminum foil 10 until the voltage at the time of the anodizing reaches the predetermined anodizing voltage before the crack forming treatment ST11 and then the crack forming treatment ST11 is performed, it is possible to avoid a phenomenon that the formation films (the first formation film 5 and the second formation film 6) become excessively thick and the aluminum foil 10 becomes excessively hard at the time point when the crack forming treatment ST11 is performed. Therefore, when stress is applied to the aluminum foil 10 in the crack formation process ST11, breakage of the aluminum foil 10 can be avoided.
In this example, since it is possible to avoid the aluminum foil 10 from becoming too hard when the crack formation process ST11 is performed, it is possible to uniformly provide the plurality of cracks 7 on the surface of the porous layers (the first porous layer 3 and the second porous layer 4) by causing stress to the aluminum foil 10. Here, if a plurality of cracks 7 are uniformly formed on the surface of the porous layers (the first porous layer 3 and the second porous layer 4), even if the thickness of the formation films (the first formation film 5 and the second formation film 6) is increased to reach the target film withstand voltage, it is possible to suppress the decrease in bending strength.
In the crack formation process ST11, a plurality of cracks 7 extending in the Y direction by a length of 300 μm or more are provided at intervals of 30 μm to 150 μm in the X direction. If such a crack 7 is provided, even in the case where the formation films (the first formation film 5 and the second formation film 6) grow due to anodic oxidation, the crack 7 can be prevented or suppressed from closing due to the formation films (the first formation film 5 and the second formation film 6).
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). In this way, even when the aluminum foil 10 is bent during the anodic oxidation, the stress due to the deformation is easily released from the crack 7.
As shown in examples described later, the formation films (the first formation film 5 and the second formation film 6) do not become excessively thick until the voltage at the time of anodic oxidation (anodic oxidation voltage) reaches 250V, and the hardness of the aluminum foil 10 is suitable for forming the crack 7. Therefore, in the formation step ST1, the anodic oxidation treatment ST3B before crack formation is performed until 250V is reached, and then the crack formation treatment ST11 is provided to apply stress to the aluminum foil 10, whereby it is easier to uniformly provide the 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)). Thus, a plurality of cracks 7 are easily formed in the porous layers (the first porous layer 3 and the second porous layer 4).
In the crack formation process ST11, among the plurality of rolls 21 that travel the aluminum foil 10, rolls 21 having a smaller diameter than the other rolls 21 are arranged as crack formation rolls (first crack formation roll 21 (1) and second crack formation roll 21 (2)). By using rolls having a small diameter as the rolls for forming cracks (the first roll 21 (1) and the second roll 21 (2)) the aluminum foil 10 is easily stressed, and cracks 7 are formed.
In the first and fifth production methods, the formation step ST1 includes a hydration step ST2 of forming a hydrated film on the aluminum foil 10 before the anodic oxidation step ST 3. Then, crack formation process ST11 is performed in the middle of hydration step ST2. 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 the hydration step ST2, cracks 7 are provided in the porous layers (the first porous layer 3 and the second porous layer 4). Thus, by the crack formation process ST11, the aluminum new surface (surface of bare metal aluminum) is exposed on the surface of the porous layers (the first porous layer 3 and the second porous layer 4) due to the crack 7. That is, the powder 11, on the surface of which the hydrated film is not formed, is exposed to the fracture surface of the porous layers (the first porous layer 3 and the second porous layer 4) caused by the crack 7. Then, in the hydration step ST2 continued after the crack formation process ST11, a hydrated film is formed on the aluminum fresh surface. Here, the hydrated film coating the aluminum fresh surface prevents or inhibits the powder 11 on both sides of the crack 7 from being bonded to each other by the formation films (the first formation film 5 and the second formation film 6) in the anodic oxidation step ST 3. Therefore, by performing the crack formation process ST11 in the middle of the hydration process ST2, when the formation films (the first formation film 5 and the second formation film 6) grow in the anodic oxidation process ST3 performed after the crack formation process ST11 and the hydration process ST2, it is possible to prevent or suppress the crack 7 from closing due to the formation films (the first formation film 5 and the second formation film 6).
In the second, third, and fourth manufacturing methods, the formation step ST1 includes a hydration step ST2 of forming a hydrated film on the aluminum foil 10 before the anodic oxidation step ST 3. In the anodic oxidation step ST3, the aluminum foil 10 on which the hydrated film is formed is anodized. In the second and third manufacturing methods, a crack formation process ST11 is performed after the hydration step ST2. With this arrangement, 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). Here, the hydrated film prevents or inhibits the powder 11 from being bonded to each other through the formation films (the first formation film 5 and the second formation film 6) in the anodic oxidation step ST 3. Therefore, by having the crack formation process ST11 after the hydration step ST2, it is easy to suppress the cracks 7 formed in the porous layers (the first porous layer 3 and the second porous layer 4) from being closed by the formation films (the first formation film 5 and the second formation film 6) formed after the hydration step ST2.
In the fourth and fifth manufacturing methods, in the anodic oxidation step ST3, the pre-crack formation anodic oxidation treatment ST3B is performed until a predetermined anodic oxidation voltage is reached, and then the crack formation treatment ST11 is performed. After the crack formation process ST11, a rehydration process ST21 is continuously performed to form a hydrated film on the aluminum foil 10. Further, post-anodic oxidation treatment ST3A is performed after the rehydration treatment ST21. With this arrangement, 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). Here, the hydrated film prevents or inhibits the powder 11 from being bonded to each other through the formation films (the first formation film 5 and the second formation film 6) in the anodic oxidation step ST 3. This makes it easy to suppress the phenomenon that the cracks 7 formed in the porous layers (the first porous layer 3 and the second porous layer 4) are closed by the formation films (the first formation film 5 and the second formation film 6). In the rehydration process ST21 continued after the crack formation process ST11, a hydrated film is formed on the aluminum new surface where the surface of the porous layers (the first porous layer 3 and the second porous layer 4) is exposed due to the formation of the crack 7. The hydrated film coating the aluminum-coated green sheet prevents or inhibits the powder 11 on both sides of the crack 7 from being bonded to each other by the formation films (the first formation film 5 and the second formation film 6) during the subsequent anodic oxidation. Therefore, by performing the rehydration process ST21 after the crack formation process ST11, it is possible to further suppress the crack 7 from closing due to the formation films (the first formation film 5 and the second formation film 6) when the formation films (the first formation film 5 and the second formation film 6) grow in the post-anodic oxidation process ST3A.
In each manufacturing method, at the end of the anodic oxidation step ST3, the aluminum foil 10 after formation, that is, the aluminized foil 1 is wound on a winding roller to form a roll shape wound in a spiral curve. At this time, since the aluminized foil 1 has a plurality of cracks 7, it is easy to wind in the X direction. Therefore, the aluminized foil 1 can be wound in a nearly round shape 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. In contrast, when the aluminized foil 1 having the plurality of cracks 7 is wound, a roll shape wound in the X direction can be formed, and no bent portion is provided in the middle. As a result, the outer dimensions of the roll in the X direction of the rolled aluminized foil 1 become smaller than the roll in the case where the aluminized foil 1 does not have cracks when the roll is rolled with the aluminized foil 1. In other words, when the external dimensions of the wound roll are the same, the roll around which the aluminized foil 1 is wound has a longer dimension in the X direction of the aluminized foil 1 after winding than the roll when the aluminized foil 1 does not have a crack. Therefore, in this example, the work efficiency of the winding work of forming the aluminized foil 1 into a roll can be improved. Further, by winding the aluminized foil 1 in a spiral curve to form a roll shape, the aluminized foil 1 can be prevented from being broken at the bent portion, as compared with the case where the aluminized foil 1 has the bent portion in the middle. Therefore, the windability of the aluminized foil 1 can be improved.
Example (example)
Fig. 13 is a table for explaining the timing of performing the crack formation process ST11 in the method for producing the aluminized foil 1 of examples 1 to 5. Fig. 14 is an explanatory diagram of timing of performing the crack formation process ST11 in the method for producing the aluminized foil 1 of examples 1 to 5. The aluminum foil 10 was subjected to the same treatment in the forming step ST1, although the timing of the crack formation treatment ST11 was different in the production methods of the aluminized foil 1 of examples 1 to 5.
In examples 1 to 5, as the base material, aluminum foil 10 having a thickness dimension T1 of the base layer 2 of 30 μm, a thickness dimension T2 of the first porous layer 3, and a thickness dimension T3 of the second porous layer 4 of 50 μm, and an average particle diameter K of the powder 11 forming the first porous layer 3 and the second porous layer 4 of 3 μm was used. In the hydration step 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 step ST3, a first anodizing treatment ST41, a second anodizing treatment ST42, and a third anodizing treatment ST43 are performed. In the anodizing step ST3, a heat treatment ST31 is performed between the second anodizing treatment ST42 and the third anodizing treatment ST43. In the heat treatment ST31, the aluminum foil 10 was heated in an atmosphere at 500 ℃ for 2 minutes to expose defective portions.
In the first anodizing treatment ST41, the aluminum foil 10 is anodized until the anodizing voltage reaches 400V. The chemical conversion treatment solution of the first anodic oxidation treatment ST41 contains ammonium adipate. The amount of ammonium adipate in the formation treatment liquid was 1g/L. The temperature of the formation treatment liquid was 80 ℃. In the second anodizing treatment ST42, the aluminum foil 10 is anodized by raising the anodizing voltage to 550V and holding for another 30 minutes. The second anodizing treatment ST42 of the formation treatment liquid contains boric acid and ammonium pentaborate octahydrate. The amount of boric acid in the formation treatment liquid was 80g/L, and the amount of ammonium pentaborate octahydrate was 0.5g/L. The temperature of the formation treatment liquid was 80 ℃. In the third anodizing treatment ST43, the anodizing voltage was raised to 550V and maintained for another 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 is used. The temperature of the formation treatment liquid was 80 ℃. The diameter dimension M of the first crack forming roller 21 (1) and the diameter dimension M of the second crack forming roller 21 (2) used in the crack forming process ST11 are 10mm.
As shown in fig. 13 and 14, example 1 is a first production method, and includes a crack formation process ST11 in the middle of a hydration step ST 2. Example 2 is a second production method, and has a crack formation process ST11 between the hydration step ST2 and the anodic oxidation step ST 3. In examples 1 and 2, the first anodic oxidation treatment ST41, the second anodic oxidation treatment ST42, and the third anodic oxidation treatment ST43 correspond to the post anodic oxidation treatment ST3A.
Examples 3 to 5 are third manufacturing methods, in which in the anodizing step ST3 included in the forming step ST1, a crack formation treatment ST11 is performed before the final target anodizing voltage (550V) is reached.
In example 3, in the first anodizing treatment ST41, the crack formation treatment ST11 was performed at a time point when the anodizing voltage reached 100V. In example 3, the first anodic oxidation treatment ST41 had an anodic oxidation voltage of 100V, which corresponds to the pre-anodic oxidation treatment ST3B, and the second anodic oxidation treatment ST42 and the third anodic oxidation treatment ST43, which correspond to the post-anodic oxidation treatment ST3A, after the crack formation treatment ST11 of the first anodic oxidation treatment ST 41.
In example 4, in the first anodizing treatment ST41, the crack formation treatment ST11 was performed at the time point when the anodizing voltage reached 200V. In example 4, the first anodic oxidation treatment ST41 had an anodic oxidation voltage of 200V, which corresponds to the pre-anodic oxidation treatment ST3B, and the second anodic oxidation treatment ST42 and the third anodic oxidation treatment ST43, which correspond to the post-anodic oxidation treatment ST3A, after the crack formation treatment ST11 of the first anodic oxidation treatment ST 41.
In example 5, in the first anodizing treatment ST41, the crack formation treatment ST11 was performed at the time point when the anodizing voltage reached 400V. In example 5, the first anodic oxidation ST41 corresponds to the pre-anodic oxidation ST3B until the anodic oxidation voltage reaches 400V, and the second anodic oxidation ST42 and the third anodic oxidation ST43 correspond to the post-anodic oxidation ST3A.
In the manufacturing method of comparative example 1, the crack formation process ST11 is not provided in the middle of the formation step ST 1. In the manufacturing method of comparative example 2, in the anodizing step ST3, the crack formation treatment ST11 is performed immediately after the second anodizing treatment ST 42. In the manufacturing method of comparative example 2, at the time point when the crack formation process ST11 was performed, the voltage output from the power supply at the time of the anodic oxidation exceeded the predetermined anodic oxidation voltage (400V), and the final anodic oxidation voltage (550V), which is the final target of the voltage at the time of the anodic oxidation, was reached.
Fig. 15 is a table showing the intervals, bending strength, tensile strength, electrostatic capacity, and film withstand voltage of the cracks 7 of the aluminum foil 10, that is, the aluminized foil 1 after the chemical conversion treatment, with respect to examples 1 to 5 and comparative examples 1 and 2. In the manufacturing method of comparative example 1, the crack formation process ST11 was not included. 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 columns of the crack intervals in fig. 15 are described as being undetectable.
The bending strength, tensile strength and capacitance were measured according to the Japanese electric mechanical Industrial Association standard "EIAJ RC-2364A". The bending strength is expressed by the number of times the aluminized foil 1 is broken. Regarding the number of bending times, the aluminized foil 1 extending in the X direction was bent 90 ° to the Z direction intersecting the X direction and the Y direction, the bending recovery was counted as 1 time, the bending recovery was counted as 2 times, the bending 90 ° in the Z direction opposite to the first time was counted as 3 times, and the bending recovery was counted as 4 times. After 5 times, the sheet was bent and counted in the same manner as 1 to 4 times. The tensile strength is a tensile force at the time of breaking when the aluminized foil 1 is stretched in the X direction.
Fig. 16 is a photograph of the surface of aluminized foil 1 manufactured by the manufacturing method of example 5 taken at an enlarged scale using a scanning electron microscope. Fig. 1 is a photograph of the surface of aluminized foil 1 produced by the production method of example 1 taken with a scanning electron microscope at an enlarged scale. Fig. 2 is a photograph of a cross section of aluminized foil 1 manufactured by the manufacturing method of example 1 taken at an enlarged scale using a scanning electron microscope.
As shown in fig. 1, 2 and 16, in the aluminized foil 1 obtained by the production method of examples 1 to 5, a plurality of cracks 7 extending in the Y direction by a length of 300 μm or more were provided at intervals of 30 μm to 150 μm on the surfaces of the first porous layer 3 and the second porous layer 4. Specifically, as shown in fig. 15, a plurality of cracks 7 are provided at intervals of 95 μm to 110 μm.
In such aluminized foil 1, even when the aluminum foil 10 is bent when the adjacent powder 11 passes through the formation films (the first formation film 5 and the second formation film 6) and is bonded by the anodic oxidation of 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 bending was more resistant than in 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 method of examples 1 to 4, the interval between the cracks 7 was narrower than in the aluminized foil 1 (see fig. 16) obtained by the manufacturing method of example 5. Therefore, as shown in fig. 15, the number of bending times indicating bending strength was larger than that of the aluminized foil 1 obtained by the manufacturing method of example 5, and bending was more resistant. Here, according to the inventors' verification, in the anodic oxidation step ST3, if the crack formation process ST11 is performed until the anodic oxidation voltage reaches 250V, the aluminized foil 1 can be made more resistant to bending than in the case where the crack formation process ST11 is performed after the anodic oxidation voltage exceeds 250V.
In addition, in the case of using the aluminized foil 1 obtained by the manufacturing method of examples 1 to 5 as an electrode for an aluminum electrolytic capacitor, the electrostatic capacity was higher than in the case of using the aluminized foil obtained by the manufacturing method of comparative example 1 as an electrode for an aluminum electrolytic capacitor. That is, since the aluminized foil 1 obtained by the production methods of examples 1 to 5 has the crack 7, the specific surface area is larger than that of the aluminized foil 1 obtained by the production method of comparative example 1. As a result, in the aluminized foil 1 (electrode for aluminum electrolytic capacitor) obtained by the manufacturing methods of examples 1 to 5, the capacitance became high.
Here, fig. 17 is a photograph of the surface of aluminized foil 1' manufactured by the manufacturing method of comparative example 1 taken at an enlarged scale by a scanning electron microscope. FIG. 18 is a photograph of a cross section of an aluminized foil 1' of comparative example 1 taken at an enlarged scale using a scanning electron microscope. As shown in fig. 17 and 18, the aluminized foil 1' manufactured by the manufacturing method of comparative example 1 has no cracks. In such aluminized foil 1', in the anodic oxidation step ST3, the formation films (the first formation film 5 and the second formation film 6) are bonded to each other by the formation film when the surface of the porous layer (the first porous layer 3 and the second porous layer 4) including the sintered body of the powder 11 grows. Therefore, when the aluminum foil is bent, the powder 11 is firmly bonded to each other, so that the stress due to the deformation cannot be released from the aluminum foil. As a result, the bonding between the powders 11 is locally broken. Further, the fracture spreads, breaking the aluminum foil. Therefore, as shown in fig. 15, in the aluminized foil 1' manufactured by the manufacturing method of comparative example 1, bending strength was low.
Fig. 19 is a table for explaining the timing of performing the crack formation process ST11 in the method for producing the aluminized foil 1 of examples 6 to 8. Fig. 20 is an explanatory diagram of the timing of performing the crack formation process ST11 in the method for producing the aluminized foil 1 of examples 6 to 8.
Examples 6 to 8 are fourth production methods, in which in the anodizing step ST3 included in the forming step ST1, the crack formation treatment ST11 and the rehydration treatment ST21 are continuously performed until the final target final anodizing voltage (550V) is reached. In examples 6 to 8, aluminum foil 10 used as a base material was the same as in examples 1 to 5. That is, in examples 6 to 8, as the base material, aluminum foil 10 having a thickness dimension T1 of the base layer 2 of 30 μm, a thickness dimension T2 of the first porous layer 3, and a thickness dimension T3 of the second porous layer 4 of 50 μm, and an average particle diameter K of the powder 11 forming the first porous layer 3 and the second porous layer 4 of 3 μm was used.
In the production method of aluminized foil 1 of examples 6 to 8, treatment of aluminum foil 10 in formation step ST1 was performed in the same manner as in examples 1 to 5. The diameter dimension M of the first crack forming roller 21 (1) and the diameter dimension M of the second crack forming roller 21 (2) used in the crack forming process ST11 are 10mm. In the rehydration treatment ST21, pure water is used as the hydration treatment liquid. Further, in the rehydration treatment 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 rehydrating treatment ST21 were continuously performed at the time point when the anodizing voltage reached 100V. In example 6, the anodic oxidation voltage of the first anodic oxidation treatment ST41 reached 100V, which corresponds to the pre-anodic oxidation treatment ST3B, and the second anodic oxidation treatment ST42 and the third anodic oxidation treatment ST43, which correspond to the post-anodic oxidation treatment ST3A, after the crack formation treatment ST11 and the rehydration treatment ST21 of the first anodic oxidation treatment ST 41.
In example 7, in the first anodizing treatment ST41, the crack formation treatment ST11 and the rehydration treatment ST21 were continuously performed at the time point when the anodizing voltage reached 200V. In example 7, the anodic oxidation voltage of the first anodic oxidation treatment ST41 reached 200V, which corresponds to the pre-anodic oxidation treatment ST3B, and the second anodic oxidation treatment ST42 and the third anodic oxidation treatment ST43, which correspond to the post-anodic oxidation treatment ST3A, after the crack formation treatment ST11 and the rehydration treatment ST21 of the first anodic oxidation treatment ST 41.
In example 8, in the first anodizing treatment ST41, the crack formation treatment ST11 and the rehydration treatment ST21 were continuously performed at the time point when the anodizing voltage reached 400V. In example 8, the first anodic oxidation ST41 corresponds to the pre-anodic oxidation ST3B until the anodic oxidation voltage reaches 400V, and the second anodic oxidation ST42 and the third anodic oxidation ST43 correspond to the post-anodic oxidation ST3A.
Fig. 21 is an explanatory diagram showing the intervals, bending strength, tensile strength, capacitance, and film withstand voltage of the cracks 7 of the aluminized foil 1, which are aluminum foil 10 after the chemical conversion treatment, in examples 6 to 8. In the aluminized foil 1 obtained by the production method of examples 6 to 8, a plurality of cracks 7 extending in the Y direction at a length of 300 μm or more were provided at intervals of 30 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. 21, in the aluminized foil 1 obtained by the production methods of examples 6 to 8, a plurality of cracks 7 were provided at intervals of 105 μm to 110. Mu.m. Therefore, even when the aluminum foil 10 is bent when the adjacent powder 11 passes through the formation films (the first formation film 5 and the second formation film 6) and is bonded by the anodic oxidation of 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 production methods of examples 6 to 8, the bending strength was 161 times or more, and bending was more resistant than in the aluminized foil 1 obtained by the production methods of comparative examples 1 and 2.
Further, since the aluminized foil 1 obtained by the production methods of examples 6 to 8 is subjected to the crack formation process ST11 and the rehydration process ST21 successively in this order, the formation films (the first formation film 5 and the second formation film 6) can be prevented or inhibited from causing the crack 7 to close when they grow in the anodic oxidation process ST 3. Further, since the formation films (the first formation film 5 and the second formation film 6) have the crack 7, when the aluminized foil 1 obtained by the production methods of examples 6 to 8 is used as an electrode for an aluminum electrolytic capacitor, the electrostatic capacity is higher than when the aluminized foil 1 obtained by the production 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 method of examples 6 and 7, the interval between the cracks 7 was narrower than in the aluminized foil 1 obtained by the manufacturing method of example 8. Therefore, as shown in fig. 21, the aluminized foil 1 obtained by the manufacturing method of examples 6 and 7 has a larger number of bending times indicating bending strength than the aluminized foil 1 obtained by the manufacturing method of example 8, and is more resistant to bending. In addition, according to the inventors' verification, in the anodic oxidation step ST3, by performing the crack formation process ST11 and the rehydration process ST21 until the anodic oxidation voltage reaches 250V, the aluminized foil 1 can be made more resistant to bending than in the case where the crack formation process ST11 is performed after the anodic oxidation voltage exceeds 250V.
Fig. 22 is a table for explaining the timing of performing the crack formation process ST11 in the method for producing the aluminized foil 1 of examples 9 to 11. Fig. 23 is an explanatory diagram of the timing of performing the crack formation process ST11 in the method for producing the aluminized foil 1 of examples 9 to 11.
Examples 9 to 11 are fifth manufacturing methods, in which crack formation process ST11 is performed in the middle of hydration step ST2 included in formation step ST 1. In examples 9 to 11, 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 voltage output from the power supply reached the final anodizing voltage (550V) as a final target. In examples 9 to 11, as the base material, aluminum foil 10 having a thickness dimension T1 of the base layer 2 of 30 μm, a thickness dimension T2 of the first porous layer 3, and a thickness dimension T3 of the second porous layer 4 of 100 μm, and an average particle diameter K of the powder 11 forming the first porous layer 3 and the second porous layer 4 of 3 μm was used. That is, in examples 9 to 11, as the base material, aluminum foil 10 having a thickness dimension of the porous layer (total 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 was used.
In examples 9 to 11, the treatment performed on the aluminum foil 10 in the formation step ST1 was the same as in examples 1 to 8. The diameter dimension M of the first crack formation roller 21 (1) and the diameter dimension M of the second crack formation roller 21 (2) used in the crack formation process ST11 are 10mm. In the rehydration treatment ST21, pure water was used as the hydration treatment liquid. In the rehydration treatment ST21, the aluminum foil 10 was 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 anodic oxidation voltage of the first anodic oxidation process ST41 reached 100V, which corresponds to the pre-anodic oxidation process ST3B, and the second anodic oxidation process ST42 and the third anodic oxidation process ST43, which correspond to the post-anodic oxidation process ST3A, after the crack formation process ST11 and the rehydration process ST21 of the first anodic oxidation process ST 41.
In example 10, in the first anodizing treatment ST41, the crack formation treatment ST11 and the rehydration treatment ST21 were continuously performed at the time point when the anodizing voltage reached 200V. In example 10, the anodic oxidation voltage of the first anodic oxidation process ST41 reached 200V, which corresponds to the pre-anodic oxidation process ST3B, and the second anodic oxidation process ST42 and the third anodic oxidation process ST43, which correspond to the post-anodic oxidation process ST3A, after the crack formation process ST11 and the rehydration process ST21 of the first anodic oxidation process ST 41.
In example 11, in the first anodizing treatment ST41, the crack formation treatment ST11 and the rehydration treatment ST21 were continuously performed at the time point when the anodizing voltage reached 400V. In example 11, the first anodic oxidation ST41 reached 400V and corresponded to the pre-anodic oxidation ST3B, and the second anodic oxidation ST42 and the third anodic oxidation ST43 corresponded to the post-anodic oxidation ST3A.
Fig. 24 is an explanatory diagram showing the intervals, bending strength, tensile strength, capacitance, and film withstand voltage of the cracks 7 of the aluminized foil 1, which are aluminum foil 10 after the formation treatment, in examples 9 to 11. In the aluminized foil 1 obtained by the production method of examples 9 to 11, a plurality of cracks 7 extending in the Y direction at intervals of 35 μm to 150 μm are provided 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 μm to 150. Mu.m. In such aluminized foil 1, even when the aluminum foil 10 is bent when the adjacent powder 11 passes through the formation films (the first formation film 5 and the second formation film 6) and is bonded by the anodic oxidation of 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 production methods of examples 9 to 11, the bending strength was 120 times or more, and bending was more resistant than in the aluminized foil 1 obtained by the production methods of comparative examples 1 and 2.
The aluminized foil 1 obtained by the manufacturing method of examples 9 to 11 was subjected to the crack formation treatment ST11 2 times, and the first crack formation treatment ST11 was performed in the middle of the hydration step ST2, and in the second crack formation treatment ST11, the rehydration treatment ST21 was performed continuously after the crack formation treatment ST 11. Therefore, even when the aluminum foil 10 having the thickness dimension of the porous layer (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 base material, it is possible to prevent or suppress the crack 7 from closing due to the formation films (the first formation film 5 and the second formation film 6) when the formation films (the first formation film 5 and the second formation film 6) grow in the anodic oxidation step ST 3.
Further, since the formation films (the first formation film 5 and the second formation film 6) had the crack 7, when the aluminized foil 1 obtained by the production methods of examples 9 to 11 was used as an electrode for an aluminum electrolytic capacitor, the electrostatic capacity was higher than when the aluminized foil 1 obtained by the production methods of comparative examples 1 and 2 was used as an electrode for an aluminum electrolytic capacitor.
Here, in the aluminized foil 1 obtained by the manufacturing method of examples 9 and 10, the interval between the cracks 7 was narrower than in the aluminized foil 1 obtained by the manufacturing method of example 11. Therefore, as shown in fig. 24, the aluminized foil 1 obtained by the manufacturing method of examples 9 and 10 has a larger number of bending times indicating bending strength than the aluminized foil 1 obtained by the manufacturing method of example 11, and is more resistant to bending. In addition, according to the inventors' verification, in the anodic oxidation step ST3, by performing the crack formation process ST11 and the rehydration process ST21 until the anodic oxidation voltage reaches 250V, the aluminized foil 1 can be made more resistant to bending than in the case where the crack formation process ST11 is performed after the anodic oxidation 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 of the aluminized foil 1 were thick. Therefore, when the aluminized foil 1 produced by the production methods of examples 8 to 11 is used as an electrode for an aluminum electrolytic capacitor, the capacitance is higher than when the aluminized foil 1 produced by the production methods of other examples is used as an electrode for an aluminum electrolytic capacitor.
(other embodiments)
Fig. 25 is a flowchart of a sixth manufacturing method of aluminized foil 1. Fig. 26 is a flowchart of a seventh manufacturing method of aluminized foil 1. The sixth production method of the aluminized foil 1 includes a rehydration process ST21 for forming a hydrated film on the aluminum foil 10 after the crack formation process ST11, in addition to the second production method shown in fig. 8. That is, as shown in fig. 25, in the sixth production method of the aluminized foil 1, the crack formation process ST11 and the rehydration process ST21 are continuously performed between the hydration process ST2 and the anodic oxidation process ST3. By doing so, the hydrated film can be provided by the rehydration process ST21 for the aluminum fresh noodle exposed by the crack 7 provided by the crack formation process ST 11. Therefore, when the formation films (the first formation film 5 and the second formation film 6) grow in the post-anodic oxidation treatment ST3A in the following anodic oxidation step ST3, it is easy to prevent or suppress the crack 7 from closing due to the formation films (the first formation film 5 and the second formation film 6).
In the pre-anodic oxidation process ST3B performed before the crack formation process ST11, the hydration step ST2 may be omitted when the predetermined anodic oxidation voltage achieved when the anodic oxidation is performed before the crack formation process ST11 is low, for example, when the predetermined anodic oxidation voltage is set to 5V or more and 150V or less. That is, the formation step ST1 may be provided with only the anodic oxidation step ST3.
In the seventh manufacturing method at this time, as shown in fig. 26, in the anodic oxidation step ST3, the pre-anodic oxidation treatment ST3B is performed to anodize the aluminum foil 10 until the predetermined anodic oxidation voltage is reached, and then the crack formation treatment ST11 is performed. After the crack formation process ST11, a post-anodic oxidation process ST3A is performed. By providing this, a plurality of cracks 7 extending in the Y direction (Y direction) with a length of 300 μm or more can be provided on the surface of the 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 by a length of 300 μm or more may be provided on the surface of the 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 powder 11 passes through the formation films (the first formation film 5 and the second formation film 6) and is bonded by the anodic oxidation of the aluminum foil 10, the stress due to the deformation can be released from the crack 7.
In the method for producing the aluminized foil 1 described with reference to fig. 7 to 11, 25, and 26, the case of performing the heat treatment ST31 after the post-anodic oxidation treatment ST3A is exemplified. The heat treatment ST31 may be performed in the middle of the anodic oxidation step ST3, before or after the pre-anodic oxidation step ST3B, before or after the post-anodic oxidation step ST3A. The heat treatment ST31 may be performed in the middle of the pre-anodic oxidation treatment ST3B or in the middle of the post-anodic oxidation treatment ST3A. Further, the heat treatment ST31 may be omitted.
As a base material for aluminizing the 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 formation step ST1, only the first crack formation roller 21 (1) is used, and the crack 7 is provided in the first porous layer 3.
In the crack formation process ST11, the first crack formation roller 21 (1) and the second crack formation roller 21 (2) are 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) is moved, whereby stress may be generated in the aluminum foil 10. That is, in the crack formation process ST11, the crack 7 can be applied to the aluminum foil 10 by relatively moving the aluminum foil 10 in the X direction with respect to the first crack formation roller 21 (1) and the second crack formation roller 21 (2).
In the crack formation process ST11, the aluminum foil 10 may be brought into contact with the first crack formation roller 21 (1) or the second crack formation roller 21 (2) at a predetermined wrap angle, and the aluminum foil 10 may be caused to travel. That is, the aluminum foil 10 may not travel between the first crack formation roller 21 (1) or the second crack formation roller 21 (2) and the pressing roller 23, but stress may be applied by the first crack formation roller 21 (1) contacting the second surface 2b of the aluminum foil 10 or the second crack formation roller 21 (2) contacting the first surface 2 a. 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 set to be 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 the first crack forming roller 21 (1) and the wrap angle of the second crack forming roller 21 (2) are within the above ranges, the desired crack 7 can be easily formed in the first porous layer 3 or the 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 liquid or blood on the surface thereof. At this time, since the aluminized foil 1 has the cracks 7 on the surface, the liquid is easily diffused.
Claims (22)
1. An aluminized foil characterized by comprising:
an aluminum foil having a first porous layer of a sintered body of a powder containing aluminum or an aluminum alloy laminated on a first surface of both surfaces of a foil-shaped base layer containing aluminum or an aluminum alloy; and
a first formation film formed on the first porous layer,
a plurality of cracks extending in a first direction in an in-plane direction by a length of 300 [ mu ] m or more 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 the surface of the first porous layer.
2. The aluminized foil according to claim 1, characterized in that:
a plurality of the cracks each reach a boundary of the base layer and the first porous layer.
3. Aluminized foil according to claim 1 or 2, characterized in that:
the aluminum foil has a dimension in the second direction that is longer than a dimension in the first direction.
4. The aluminized foil according to any one of claims 1 to 3, characterized in that:
The first porous layer has a thickness of 10 μm or more and 500 μm or less.
5. The aluminized foil according to any one of claims 1 to 4, characterized in that:
the average particle diameter of the powder is 1-20 μm.
6. The aluminized foil according to any one of claims 1 to 5, characterized in that:
the thickness of the base layer is 10 [ mu ] m or more and 100 [ mu ] m or less.
7. The aluminized foil according to any one of claims 1 to 6, characterized in that:
a second porous layer formed by laminating a sintered body of a powder containing aluminum or an aluminum alloy on a second surface of the base layer opposite to the first surface,
a second formation coating film is formed on the second porous layer,
a plurality of the cracks extending in the in-plane direction thereof are provided at the surface of the second porous layer at the intervals.
8. An electrode for an aluminum electrolytic capacitor, characterized in that:
an aluminized foil comprising 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 in a roll shape wound in a swirl curve in the second direction.
10. An aluminized foil characterized by comprising:
An aluminum foil having a first porous layer of a sintered body of a powder containing aluminum or an aluminum alloy laminated on a first surface of both surfaces of a foil-shaped base layer containing aluminum or an aluminum alloy; and
a first formation film formed on the first porous layer,
on the surface of the first porous layer, a plurality of cracks extending in a first direction of an in-plane direction are provided separately in a second direction of the in-plane direction and orthogonal to the first direction,
a plurality of the cracks each reach a boundary of the base layer and the first porous layer.
11. An electrode for an aluminum electrolytic capacitor, characterized in that:
an aluminized foil comprising the method of claim 10.
12. The electrode for an aluminum electrolytic capacitor as recited in claim 11, wherein:
the aluminized foil is in a roll shape wound in a swirl curve in the second direction.
13. A method of manufacturing aluminized foil, characterized by:
comprises a formation step of forming a first formation film on an aluminum foil having a first porous layer of a sintered body of a powder containing aluminum or an aluminum alloy laminated on a first surface of a foil-like base layer containing aluminum or an aluminum alloy,
the forming step includes an anodizing step of anodizing the aluminum foil,
In the forming step, a crack formation process is performed in which the aluminum foil is subjected to stress, a plurality of cracks extending in the first direction are provided on the surface of the first porous layer so as to be separated in a second direction orthogonal to the first direction,
and performing a post-crack-formation anodizing treatment in the anodizing step, wherein the post-crack-formation anodizing treatment is a treatment of anodizing the aluminum foil after the crack-formation treatment.
14. The method for producing aluminized foil as recited in claim 13, wherein:
in the crack formation process, a plurality of the cracks extending in the first direction by a length of 300 μm or more are provided at intervals of 30 μm to 150 μm in the second direction.
15. The method for producing an aluminized foil as claimed in claim 13 or 14, characterized in that:
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 for producing an aluminized foil as claimed in any one of claims 13 to 15, characterized in that:
in the step of anodizing, a pre-crack-formation anodizing treatment is performed in which the aluminum foil is anodized until a predetermined anodizing voltage is reached before the crack-formation treatment,
The predetermined anodic oxidation voltage in the anodic oxidation treatment before crack formation is 400V or less.
17. The method for producing an aluminized foil as claimed in any one of claims 13 to 16, characterized in that:
in the crack formation process, a first crack formation roller extending in the first direction is brought into contact with a second surface opposite to the first surface of the two surfaces of the aluminum foil, and the aluminum foil and the first crack formation roller are relatively moved in the second direction.
18. The method for producing aluminized foil as recited in claim 17, wherein:
in the forming step, the aluminum foil is caused to travel in the second direction by a plurality of rollers arranged along the second direction,
among the plurality of rolls, a roll having a smaller diameter than the other rolls is arranged as the first crack forming roll.
19. The method for producing an aluminized foil as claimed in claim 17 or 18, characterized in that:
in the aluminum foil, a second porous layer of a sintered body of powder containing aluminum or an aluminum alloy is laminated on a second surface of the base layer opposite to the first surface,
in the forming 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 relatively moved in the second direction.
20. The method for producing an aluminized foil as claimed in any one of claims 13 to 19, characterized in that:
the forming step includes a hydration step of forming a hydrated film on the aluminum foil before the anodizing 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 for producing an aluminized foil as claimed in any one of claims 13 to 19, characterized in that:
the forming step includes a hydration step of forming a hydrated film on the aluminum foil before the anodizing 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 for producing aluminized foil as recited in claim 21, wherein:
Comprising a rehydration treatment of forming a hydrated film on the aluminum foil after the crack formation treatment.
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| PCT/JP2020/018247 WO2020241174A1 (en) | 2019-05-24 | 2020-04-30 | Aluminum conversion foil, electrode for aluminum electrolytic capacitors, and method for manufacturing aluminum conversion foil |
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