US20020149902A1 - Electrode foil for aluminum electrolytic capacitor and method of manufacturing the same - Google Patents

Electrode foil for aluminum electrolytic capacitor and method of manufacturing the same Download PDF

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US20020149902A1
US20020149902A1 US10/073,860 US7386002A US2002149902A1 US 20020149902 A1 US20020149902 A1 US 20020149902A1 US 7386002 A US7386002 A US 7386002A US 2002149902 A1 US2002149902 A1 US 2002149902A1
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United States
Prior art keywords
etching
foil
pits
electrode plates
electrolytic capacitor
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US10/073,860
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English (en)
Inventor
Nobuhiko Yamazaki
Kazuaki Nakanishi
Shinichi Yamaguchi
Hisao Ohishi
Ryoichi Shimatani
Akihiro Yamaguchi
Kazuko Hasegawa
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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Priority claimed from JP2001036544A external-priority patent/JP2002246274A/ja
Priority claimed from JP2001053994A external-priority patent/JP4284874B2/ja
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Assigned to MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. reassignment MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HASEGAWA, KAZUKO, NAKANISHI, KAZUAKI, OHISHI, HISAO, SHIMATANI, RYOICHI, YAMAGUCHI, AKIHIRO, YAMAGUCHI, SHINICHI, YAMAZAKI, NOBUHIKO
Priority to US10/234,467 priority Critical patent/US6611422B2/en
Publication of US20020149902A1 publication Critical patent/US20020149902A1/en
Abandoned legal-status Critical Current

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    • 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
    • H01G9/055—Etched foil electrodes

Definitions

  • the present invention relates to an electrode foil used for an aluminum electrolytic capacitor, and particularly concerns an electrode foil for an aluminum electrolytic capacitor for a high and medium voltage and a method of manufacturing the same.
  • a typical aluminum electrolytic capacitor is configured such that a capacitor element is composed of an anode foil and a cathode foil that are wound via a separator, the capacitor element is dipped into an electrolytic solution for driving, and the capacitor element is sealed into a metallic case.
  • the anode foil has a dielectric oxide film formed by performing anodic oxidation on a surface of aluminum foil, which has an effective surface area increased by etching.
  • the cathode foil includes aluminum foil whose effective surface area is increased by etching.
  • the above method of etching the anode foil is performed chemically or electrochemically in a solution of hydrochloric acid, in which acid such as sulfuric acid, nitric acid, phosphoric acid, and oxalic acid for forming a film is added.
  • a method of etching the anode foil used for a medium and high voltage basically includes a first etching step of generating main pits and a final etching step of increasing the main pits in a diameter suitable for a used voltage of an aluminum electrolytic capacitor. An important point is how to generate a large number of main pits and to efficiently increase the main pits in size.
  • a technique for increasing an effective surface area of the anode foil includes a first etching step of electrochemically performing etching using a direct current in a solution of hydrochloric acid or the like, an middle etching step of performing etching using a direct current in a solution of neutral salt such as sodium chloride, and a final etching step of performing electrical etching in a solution of nitric acid, sulfuric acid, or mixed acid thereof.
  • a large number of main pits can be formed from a surface and an effective surface area on aluminum foil can be increased by forming branched sub pits at the midpoints or the ends of the main pits.
  • JP60-36700A includes a first preliminary corrosion step using acid and a second anodizing step of treatment using a direct current with a high current density.
  • Aluminum foil is subjected to an alternating current (AC) treatment and is corroded in the first preliminary corrosion step, and the aluminum foil is subjected to a direct current (DC) treatment in the second anodizing step, so that the aluminum foil is increased in electrostatic capacitance and mechanical strength.
  • AC alternating current
  • DC direct current
  • an etching solution which includes at least one of a solution of neutral salt and a solution of acid salt solution.
  • the solution of neutral salt contains at least one of three kinds of chlorine ions including sodium chloride, ammonium chloride, and potassium chloride.
  • FIG. 9 is a schematic diagram showing a cross section of etching pits formed by etching on the conventional aluminum foil 63 .
  • the present invention is achieved to solve the above-mentioned conventional problems and has as its object the provision of an electrode foil for an aluminum electrolytic capacitor and a method of manufacturing the same, by which sub pits branched on a surface layer of an aluminum foil can be reduced with high mechanical strength and large electrostatic capacitance.
  • the electrode foil for an aluminum electrolytic capacitor of the present invention is configured such that a large number of main pits are formed by etching from a surface of aluminum foil in a thickness direction on both surfaces of aluminum foil, and sub pits are branched from the vicinity of a surface layer other than the surface layer on the main pits to the ends of the main pits. With this configuration, sub pits branched on the surface layer of aluminum foil are not formed in the present invention, thereby increasing an electrostatic capacitance of the electrode foil for an aluminum electrolytic capacitor.
  • the sub pits are shorter than the main pits. Such a configuration can increase mechanical strength of the electrode foil for an aluminum electrolytic capacitor of the present invention.
  • the method of manufacturing the electrode foil for an aluminum electrolytic capacitor of the present invention comprises a first etching step in which aluminum foil is dipped into an etching solution of an acidic aqueous solution containing hydrochloric acid and sulfuric acid and/or nitric acid and a direct current is supplied to form main pits, an middle etching step in which the direct current is supplied and etching is performed in an etching solution of neutral salt containing an additive therein to effectively form the sub pits branched from the midpoints or the ends of the main pits other than the surface layer on the main pits, and a final etching step of increasing the main pits and the sub pits in diameter.
  • At least one or more additives are selected from oxalic acid, citric acid, phosphoric acid, boric acid, succinic acid, and malonic acid. Further, in the manufacturing method of the present invention, a concentration of the additive ranges from 0.01 to 1.0%. With this method, it is possible to obtain the effect of the manufacturing method more effectively.
  • the electrode foil for an aluminum electrolytic capacitor of the present invention in the middle etching step of the above-mentioned manufacturing method, when a direct current is supplied and etching is performed, DC etching is performed while aluminum foil is passed through pairs of electrode plates in a plurality of etching tanks having a plurality of pairs of electrode plates, and a pair of electrode plates for supplying an alternating current is provided to perform AC etching at an upper or lower position of at least a pair of electrode plates among the plurality of electrode plates provided in the plurality of etching tanks.
  • the surfaces of aluminum foil and etching pits are made rough by supplying an alternating current and a hydrated film is formed.
  • a pair of electrode plates for supplying a direct current is always provided right after a pair of electrode plates for supplying an alternating current.
  • etching pits can be formed by using a direct current more efficiently than the effect of the above-mentioned manufacturing method.
  • a pair of electrode plates for supplying an alternating current partially interrupts a pair of electrode plates for supplying a direct current.
  • the present invention can readily provide a pair of electrode plates for supplying an alternating current.
  • a pair of electrode plates for supplying an alternating current is 0.01 to 0.15A/cm 2 in current density.
  • the present invention can enhance the effects of the above-mentioned manufacturing method.
  • etching is performed by supplying a direct current as follows: DC etching is performed while aluminum foil is passed through a pair of electrode plates in a plurality of etching tanks having a plurality of pairs of electrode plates, and DC etching is performed while an electrical insulating material partially interrupts at least a pair of electrode plates among the plurality of pairs of electrode plates provided in the plurality of etching tanks.
  • the present invention can obtain a uniform current density in an electrolytic solution, so that etching pits formed on aluminum foil are equal in length. Further, it is possible to increase etching efficiency, thereby achieving a larger effective surface area of aluminum foil.
  • an electrical insulating material includes an opening composed of a plurality of holes or a plurality of slits. Hence, it is possible to obtain a more uniform current density in an electrolytic solution.
  • FIG. 1 is a schematic diagram showing a cross section of etching pits of an etching foil in an electrode foil for an aluminum electrolytic capacitor according to Embodiment 1 of the present invention
  • FIG. 2 is a flowchart showing etching steps of the etching foil according to Embodiment 1;
  • FIG. 3 is a sectional view showing an etching tank on a previous step and a subsequent step that is used in Example 10 of Embodiment 2;
  • FIG. 4(A) is a perspective view showing a configuration of an electrode plate according to Example 10 of Embodiment 2;
  • FIG. 4(B) is a perspective view showing a configuration of an electrode plate according to Examples 6 to 12 of Embodiment 2;
  • FIG. 5 is a sectional view showing an intermediate-step etching tank used in Example 10 of Embodiment 2;
  • FIG. 6 is a sectional view showing an intermediate-step etching tank used in Example 11 of Embodiment 2;
  • FIG. 7 is a sectional view showing an intermediate-step etching tank used in Example 12 of Embodiment 2;
  • FIG. 8 is a sectional view showing an intermediate-step etching tank used in Example 13 of Embodiment 2.
  • FIG. 9 is a schematic diagram showing a cross section of etching pits of etching foil in conventional electrode foil for an aluminum electrolytic capacitor.
  • FIG. 1 is a schematic diagram showing a cross section of etching pits on an etching foil provided in an electrode foil for an aluminum electrolytic capacitor.
  • reference numeral 1 denotes an aluminum foil
  • reference numeral 2 denotes main pits extending in a thickness direction from a surface of the aluminum foil 1
  • reference numeral 3 denotes sub pits branched from the vicinity of a surface layer other than the surface layer on the main pits 2 to ends of the main pits 2 .
  • Such a configuration of the etching foil can increase an electrostatic capacitance and mechanical strength of the electrode foil.
  • FIG. 2 is a flowchart showing etching steps of the etching foil.
  • aluminum foil is prepared, and may be subjected to pretreatment in an acid solution, an alkali solution, or the like.
  • an important point is how to generate uniform main pits 2 in the aluminum foil 1 with increasing a density of the main pits.
  • etching is electrochemically performed by using an etching solution of an acidic aqueous solution, in which hydrochloric acid, sulfuric acid, and/or nitric acid are added.
  • a concentration of hydrochloric acid in the acidic aqueous solution preferably ranges from 2 to 15%. When a concentration is 2% or less, sufficient pits cannot be formed. When a concentration exceeds 15%, the surface of the aluminum foil is melted. A suitable range is 4 to 12%.
  • a density of generated pits can be further increased by adding sulfuric acid and/or nitric acid.
  • An amount of addition preferably ranges from 0.1 to 15.
  • a temperature of the above etching solution of an acid solution also considerably affects the generation of the main pits 2 .
  • a temperature is below 50° C.
  • a generating density of the main pits 2 is small.
  • a temperature exceeds 100° C.
  • the surface of the aluminum foil 1 is melted.
  • a temperature of the etching solution preferably ranges from 50 to 100° C.
  • the sub pits 3 are formed perpendicularly to the main pits 2 formed in the first etching step to increase a density of etching pits.
  • the present invention regulates the formation of the sub pits 3 in the middle etching step. Namely, by performing etching on both surfaces of the aluminum foil 1 , the sub pits 3 are provided on a large number of the main pits 2 provided from the surface in a thickness direction. The sub pits 3 are branched from the midpoints and the ends of the main pits 2 except for the surface layer on the main pits 2 . Hence, it is possible to obtain the etching foil with high mechanical strength and a large electrostatic capacitance.
  • the etching solution used in the middle etching step is prepared by adding at least an element selected from oxalic acid, citric acid, phosphoric acid, boric acid, succinic acid, and malonic acid to an aqueous solution of neutral salt such as sodium chloride, ammonium chloride, and potassium chloride.
  • the above etching solution is used for etching. With the above method, it is possible to form the sub pits 3 which are branched from the midpoints and the ends of the main pits 2 except for the surface layer on the main pits 2 .
  • a concentration of the solution of neutral salt preferably ranges from 0.5 to 10%. When a concentration is less than 0.5%, the growth of the sub pits 3 is small. When a concentration exceeds 10%, a thick oxide film is formed entirely on the surfaces of the main pits 2 , thereby interfering with the formation of the sub pits 3 . Further, a concentration of the above additive preferably ranges from 0.01 to 1.0%. When a concentration of the additive is less than 0.01%, the sub pits 3 are formed on the surface layer of the aluminum foil 1 . When a concentration of the additive exceeds 1.0%, a forming density of the sub pits 3 is reduced.
  • an intermediate treatment may be optionally performed before the middle etching step.
  • the intermediate treatment removes an uneven film on the surface of the aluminum foil 1 after the first etching step and activates the surface of the aluminum foil 1 .
  • an acidic aqueous solution which contains at least an element selected from hydrochloric acid, hydrogen fluoride, and nitric acid.
  • the aluminum foil 1 on which the main pits 2 are formed in the first etching step is dipped into the solution.
  • An oxygen concentration of the acidic aqueous solution preferably ranges from 2 to 10%. When an oxygen concentration is below 2%, a film is not sufficiently removed. When an oxygen concentration exceeds 10%, the surface of the aluminum foil 1 is melted. Further, a temperature of the acidic aqueous solution preferably ranges from 50 to 90° C.
  • the main pits 2 and the sub pits 3 that are formed in the first etching step and the middle etching step are increased in a diameter while the melting of the surface of the aluminum foil 1 is suppressed.
  • an etching solution used for the final etching step it is preferable to adopt an etching solution prepared by adding at least an element selected from oxalic acid, chromic acid, acetic acid, phosphoric acid, citric acid, and boric acid to sulfuric acid or nitric acid.
  • a concentration of the etching solution preferably ranges from 0.1 to 5.0%. When a concentration is below 0.1%, the surface of the aluminum foil 1 is melted. When a concentration exceeds 5.0%, a too large oxide film is formed on the surface of the aluminum foil 1 , so that the bits are less likely to increase in diameter.
  • the etching foil when the sub pits 3 are formed in the middle etching step, by performing etching in an aqueous solution of neutral salt where an additive is added, oxide films are formed with different thicknesses on the surfaces of the aluminum foil 1 and the main pits 2 .
  • oxide films are formed with different thicknesses on the surfaces of the aluminum foil 1 and the main pits 2 .
  • Embodiment 1 will be discussed in detail in accordance with the following examples.
  • the aluminum foil 1 was dipped into an etching solution of an acidic aqueous solution (hydrochloric acid concentration of 10%, sulfuric acid concentration of 10%) at 85° C., etching was performed while direct current having a current density of 20A/dm 2 was supplied for 250 seconds, and main pits 2 were formed.
  • an acidic aqueous solution hydrochloric acid concentration of 10%, sulfuric acid concentration of 10%
  • the aluminum foil 1 was dipped into an aqueous solution of sulfuric acid having a temperature of 40° C. and a concentration of 0.5% for 60 seconds.
  • the aluminum foil 1 was dipped into an aqueous solution of neutral salt (3.0% of sodium chloride, 0.1% of oxalic acid) at 70° C., etching was performed while direct current having a current density of 15A/dm 2 was supplied for 250 seconds, and sub pits 3 were formed.
  • neutral salt 3.0% of sodium chloride, 0.1% of oxalic acid
  • the aluminum foil 1 was dipped into an aqueous solution of nitric acid having a temperature of 70° C. and a concentration of 3%, direct current with a current density of 10A/dm 2 is supplied for 600 seconds, the main pits and the sub pits were increased in diameter, and finally as dechlorination, the aluminum foil 1 was cleaned for one minute in an aqueous solution of nitric acid having a temperature of 50° C. and a concentration of 10% so as to form etching foil.
  • An etching foil was formed in the same manner as Example 1 except that the aqueous solution of neutral salt used in the middle etching step of Example 1 was replaced with an aqueous solution of neutral salt that contained 3.0% of potassium chloride and 0.1% of oxalic acid.
  • An etching foil was formed in the same manner as Example 1 except that the aqueous solution of neutral salt used in the middle etching step of Example 1 was replaced with an aqueous solution of neutral salt that contained 3.0% of ammonium chloride and 0.1% of oxalic acid.
  • An etching foil was formed in the same manner as Example 1 except that the aqueous solution of neutral salt used in the middle etching step of Example 1 was replaced with an aqueous solution of neutral salt that contained 3.0% of ammonium chloride and 0.2% of boric acid.
  • An etching foil was formed in the same manner as Example 1 except that the aqueous solution of neutral salt used in the middle etching step of Example 1 was replaced with an aqueous solution of neutral salt that contained 3.0% of ammonium chloride and 0.1% of phosphoric acid.
  • An etching foil was formed in the same manner as Example 1 except that the aqueous solution of neutral salt used in the middle etching step of Example 1 was replaced with an aqueous solution of neutral salt that contained 3.0% of ammonium chloride and 0.3% of citric acid.
  • An etching foil was formed in the same manner as Example 1 except that the aqueous solution of neutral salt used in the middle etching step of Example 1 was replaced with an aqueous solution of neutral salt that contained 3.0% of ammonium chloride and 1.0% of succinic acid.
  • An etching foil was formed in the same manner as Example 1 except that the aqueous solution of neutral salt used in the middle etching step of Example 1 was replaced with an aqueous solution of neutral salt that contained 3.0% of ammonium chloride and 0.005, 0.01, 0.05, 0.1, 0.5, 1.0, and 1.5% of succinic acid.
  • An etching foil was formed in the same manner as Example 1 except that the acidic aqueous solution used in the first etching step of Example 1 was replaced with an etching solution that contained 10% of hydrochloric acid and 10% of nitric acid.
  • An etching foil was formed in the same manner as Example 1 except that the aqueous solution of neutral salt used in the middle etching step of Example 1 was replaced with an aqueous solution of neutral salt that contained 3.0% of sodium chloride (no additive).
  • the etching foil of Examples 1 to 9 of the present invention includes the sub pits 3 , which were branched from the midpoints and the ends of the main pits 2 except for the surface layer on the main pits 2 , on the large number of main pits 2 formed by etching in a thickness direction on both surfaces of the aluminum foil 1 .
  • the sub pits 3 which were branched from the midpoints and the ends of the main pits 2 except for the surface layer on the main pits 2 , on the large number of main pits 2 formed by etching in a thickness direction on both surfaces of the aluminum foil 1 .
  • an amount of additive which was added to an aqueous solution of neutral salt was set at 0.01 to 1.0%.
  • Example 1 Furthermore, the same characteristics as Example 1 can be obtained when the acid aqueous solution of the first etching step is replaced with an etching solution using hydrochloric acid and nitric acid.
  • a pair of electrode plates for supplying alternating current is provided for AC etching at an upper or lower position of at least a pair of electrode plates among a plurality of pairs of electrode plates provided in an etching tank.
  • a pair of electrode plates for supplying alternating current is provided for AC etching at an upper or lower position of at least a pair of electrode plates among a plurality of pairs of electrode plates provided in an etching tank.
  • a pair of electrode plates for supplying direct current partially interrupts direct current supplied between the aluminum foil and the pair of electrode plates by using an electrical insulating material.
  • a current density in an electrolytic solution can be uniform, etching pits can be formed with uniform lengths on the aluminum foil.
  • etching efficiency can be also improved, an effective surface area of the aluminum foil can be further increased. As a result, it is possible to obtain etching foil with a large electrostatic capacitance and high mechanical strength.
  • Pretreatment was performed by dipping aluminum foil with a purity of 99.98% and a thickness of 100 ⁇ m into an aqueous solution of 0.5% NaOH for one minute.
  • FIG. 3 reference numeral 1 denotes aluminum foil
  • reference numerals 12 a and 12 b denote pairs of electrode plates disposed so as to be opposed to the aluminum foil 1
  • reference numerals 13 a and 13 b denote current supply rollers for feeding a current to the aluminum foil 1
  • reference numerals 14 a and 14 b denote inter-tank rollers disposed in the etching tank 15
  • arrows indicate a direction of conveying the aluminum foil 1 .
  • the pairs of electrode plates 12 a and 12 b were configured as shown in FIG. 4(A).
  • reference numeral 12 denotes an electrode plate.
  • the upper part and the central part of the electrode plate 12 was covered with an electrical insulating material 18 , on which slits 17 a were partially formed in a horizontal direction, and the electrode plate 12 was exposed on the lower part other than the sides.
  • the slits 17 a the lower slits were larger in width than the upper slits, and the lower slits were smaller in interval.
  • the aluminum foil 1 was etched in the etching tank 15 , first, the aluminum foil 1 was dipped into an electrolytic solution (not shown) via the current supply rollers 13 a and were subjected to direct current etching between the pairs of electrode plates 12 a disposed so as to be opposed to the aluminum foil 1 in the electrolytic solution. And then, the aluminum foil 1 passed through the inter-tank rollers 14 a and 14 b , current was passed to the aluminum foil 1 again from the current supply roller 13 b , and the aluminum foil was subjected to DC etching between the pair of electrode plates 12 b disposed so as to be opposed to the aluminum foil 1 . Hence, the aluminum foil 1 was continuously provided on which main pits 2 are formed.
  • an electrolytic solution was used, which was prepared by adding 1% sulfuric acid to 10% hydrochloric acid at 85° C. Direct current with a current density of 2000A/cm 2 was supplied to the pair of electrode plates 12 a and 12 b to perform DC etching, and then, the electrode plates 12 a and 12 b were cleaned with water.
  • the aluminum foil was continuously subjected to DC etching using etching tanks shown in FIG. 5. Two etching tanks were provided. Electrode plates 22 and 23 were disposed in parallel in the tanks 26 and 27 , and aluminum foil 1 passed through the electrode plates while meandering. In FIG.
  • reference numerals 22 a , 22 b , 22 c , and 22 d denote pairs of electrode plates that were disposed so as to be opposed to the aluminum foil 1
  • reference numerals 24 a and 24 b denote current supply rollers for feeding a current to the aluminum foil 1
  • reference numerals 25 a , 25 b , 25 c , and 25 d denote inter-tank rollers disposed in the etching tanks 26 and 27
  • reference numeral 23 denotes a pair of electrode plates for supplying alternating current
  • arrows indicate a direction of conveying the aluminum foil 1 .
  • the pairs of electrode plates 22 a , 22 b , 22 c , and 22 d that were opposed to the aluminum foil 1 were each configured as shown in FIG. 4(A).
  • the aluminum foil 1 was etched as follows: first, the aluminum foil 1 was dipped into an electrolytic solution (not shown) via the current supply roller 24 a and was subjected to DC etching between the pair of electrode plates 22 a opposed to the aluminum foil 1 in the electrolytic solution. And then, the aluminum foil 1 passed by the inter-tank rollers 25 a and 25 b and was subjected to direct current etching again between the pair of electrode plates 22 b opposed to the aluminum foil 1 . The aluminum foil 1 was shifted to the etching tank 27 and was subjected to alternating current etching between the pair of electrode plates 23 where alternating current was supplied.
  • the aluminum foil 1 was subjected to DC etching between the pair of electrode plates 22 c , and then, the aluminum foil 1 passed by the inter-tank rollers 25 c and 25 d and was subjected to direct current etching again between the pair of electrode plates 22 d opposed to the aluminum foil 1 .
  • an electrolytic solution was used which was an aqueous solution of neutral salt containing 3% ammonium chloride at 90° C.
  • Direct current with a current density of 1200A/cm 2 was supplied to the pair of electrode plates 22 a and 22 c
  • direct current with a current density of 600A/cm 2 was supplied to the pair of electrode plates 22 b and 22 d .
  • alternating current with a sine wave having a frequency of 20 Hz and a current density of 0.1A/cm 2 was supplied to the pair of electrode plates 23 , and etching was performed. And then, the aluminum foil 1 was cleaned with water.
  • an electrolytic solution used in the final etching step an electrolytic solution was used in which 0.5% boric acid was added to an aqueous solution of 5% nitric acid at 50° C. A direct current with a current density of 1000A/cm 2 was supplied to the pair of electrode plates 12 a and 12 b to perform DC etching, and then, the aluminum foil 1 was washed with water. Finally, dechlorination was performed to form etching foil.
  • An etching foil was formed in the same manner as Example 10 except that the pairs of electrode plates 22 a , 22 b , 22 c , and 22 d were each configured as shown in FIG. 4(B).
  • the electrode plates were opposed to the aluminum foil 1 in the first etching step of Example 10.
  • the upper part and the central part of the electrode plate of FIG. 4(B) were covered with an electrical insulating material 18 on which oval holes 17 b were formed in an array.
  • An electrode plate 16 was exposed on the lower part other than the sides.
  • the holes 17 b were small on the upper part and large on the lower part.
  • the holes on the lower part had smaller intervals in a vertical direction.
  • Example 12 an etching foil was formed in the same manner as Example 10 except that aluminum foil 1 was continuously subjected to DC etching using etching tanks of FIG. 6 in the middle etching step of Example 10.
  • reference numerals 32 a , 32 b , 32 c , and 32 d denote pairs of electrode plates disposed so as to be opposed to the aluminum foil 1
  • reference numerals 34 a and 34 b denote current supply rollers for feeding a current to the aluminum foil 1
  • reference numerals 35 a , 35 b , 35 c , and 35 d denote inter-tank rollers disposed in etching tanks 36 and 37
  • reference numerals 33 a and 33 b denote pairs of electrode plates for supplying alternating current
  • arrows indicate a direction of conveying the aluminum foil 1 .
  • the present example is characterized in that the electrode plates 33 a for supplying alternating current are provided in the etching tank 36 as well.
  • alternating current with a sine wave having a frequency of 20 Hz and a current density of 0.1A/cm 2 was supplied to the pairs of electrode plates 33 a and 33 b for supplying alternating current.
  • Example 13 an etching foil was formed in the same manner as Example 10 except that aluminum foil 1 was continuously subjected to direct current etching by using etching tanks of FIG. 7 in the middle etching step of Example 10.
  • reference numerals 42 a , 42 b , 42 c , and 42 d denote pairs of electrode plates disposed so as to be opposed to the aluminum foil 1
  • reference numerals 44 a and 44 b denote current supply rollers for feeding a current to the aluminum foil 1
  • reference numerals 45 a , 45 b , 45 c , and 45 d denote inter-tank rollers disposed in etching tanks 46 and 47
  • reference numerals 43 a , 43 b , and 43 c denote pairs of electrode plates for supplying alternating current
  • arrows indicate a direction of conveying the aluminum 1 .
  • Example 13 the pair of electrode plates 43 a for supplying alternating current was disposed in the etching tank 46 , and the electrode plates 43 b and 43 c were disposed in the etching tank 47 . Additionally, the electrode plates 43 a , 43 b , and 43 c were disposed alternately in a vertical direction.
  • an alternating current with a sine wave having a frequency of 20 Hz and a current density of 0.1A/cm 2 was supplied to the pairs of electrode plates 43 a , 43 b , and 43 c for supplying alternating current.
  • Example 14 an etching foil was formed in the same manner as Example 10 except that aluminum foil 1 was continuously subjected to direct current etching using etching tanks of FIG. 8 in the middle etching step of Example 10.
  • reference numerals 52 a , 52 b , 52 c , and 52 d denote pairs of electrode plates disposed so as to be opposed to the aluminum foil 1
  • reference numerals 54 a and 54 b denote current supply rollers for feeding a current to the aluminum foil 1
  • reference numerals 55 a , 55 b , 55 c , and 55 d denote inter-tank rollers disposed in etching tanks 56 and 57
  • reference numeral 53 denotes a pair of electrode plates for supplying alternating current.
  • Insulating plates 58 for interrupting direct current are provided on the backs of the electrode plates. Arrows indicate a direction of conveying the aluminum foil 1 .
  • a plurality of pairs of the electrode plates 53 may be provided for supplying alternating current.
  • the electrodes may be vertically arranged as the electrode plates 33 a , 33 b , 43 a , 43 b , and 43 c of FIGS. 6 and 7.
  • an aluminum foil was formed by supplying alternating current with a sine wave having a frequency 15 Hz and current densities of 0,005, 0.01, 0.05, 0.1, 0.15, and 0.2A/cm 2 to the pair of electrode plates 53 for supplying alternating current.
  • Example 15 an etching foil was formed in the same manner as Example 10 except that the pairs of electrode plates 12 a and 12 b , which were opposed to the aluminum foil 1 in the first etching step of Example 10, were each configured as shown in FIG. 4(B), and the pairs of electrode plates 12 a and 12 b , which were opposed to the aluminum foil 1 in the final etching step, were also configured as shown in FIG. 4(B).
  • an etching foil was formed in the same manner as Example 10 except that the aluminum foil 1 was continuously subjected to DC etching by using two etching tanks 15 (no alternating current was supplied) of FIG. 3 in the middle etching step of Example 10 .
  • pairs of electrode plates 12 a and 12 b for supplying direct current did not include an electrical insulating material 18 for partially interrupting direct current.
  • the etching foil of Examples 10 to 15 of the present invention can be larger in effective surface area of the aluminum foil as compared with etching foil of Comparative Example 2. Consequently, it is possible to obtain etching foil with a large electrostatic capacitance and high mechanical strength.
  • a large number of main pits are provided by etching on both surfaces of aluminum foil in a thickness direction from the surface, and sub pits are branched from the vicinity of a surface layer other than the surface layer on the main pits to the ends of the main pits.
  • the branched sub pits are not formed on the surface layer of the aluminum foil.
  • the manufacturing method is a method of manufacturing anode foil used for an aluminum electrolytic capacitor.
  • an aluminum foil is passed through pairs of electrode plates in a plurality of etching tanks including a plurality of pairs of electrode plates, and DC etching is performed.
  • a pair of electrode plates are provided for supplying alternating current to perform AC etching.

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JP2001036544A JP2002246274A (ja) 2001-02-14 2001-02-14 アルミ電解コンデンサ用電極箔およびその製造方法
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US20040168929A1 (en) * 2002-12-05 2004-09-02 Dina Katsir Electrodes for electrolytic capacitors and method for producing them
US9978530B2 (en) * 2013-12-19 2018-05-22 Pacesetter, Inc. Method of nano-patterning a foil surface
USD860134S1 (en) * 2017-07-10 2019-09-17 Nippon Chemi-Con Corporation Electrode foil for capacitor
USD860135S1 (en) * 2017-07-10 2019-09-17 Nippon Chemi-Con Corporation Electrode foil for capacitor
US10957491B2 (en) 2016-09-16 2021-03-23 Japan Capacitor Industrial Co., Ltd. Electrolytic capacitor-specific electrode member and electrolytic capacitor
CN114141539A (zh) * 2021-12-08 2022-03-04 南通海星电子股份有限公司 一种弯曲疲劳强度良好低压电极箔的制备方法

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JP4893183B2 (ja) * 2006-09-20 2012-03-07 日本軽金属株式会社 電解コンデンサ用アルミニウム電極板
RU2559815C1 (ru) * 2014-01-31 2015-08-10 Открытое акционерное общество "Элеконд" Способ получения высокоразвитой поверхности на рекристаллизованной алюминиевой электродной фольге для электролитического конденсатора
JP1595451S (fr) * 2017-06-20 2018-01-22
US12525407B2 (en) * 2021-01-29 2026-01-13 Panasonic Intellectual Property Management Co., Ltd. Electrode foil for electrolytic capacitors, and electrolytic capacitor
CN117612868B (zh) * 2024-01-18 2024-04-26 南通南辉电子材料股份有限公司 一种中压腐蚀箔的制造方法

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US20040168929A1 (en) * 2002-12-05 2004-09-02 Dina Katsir Electrodes for electrolytic capacitors and method for producing them
EP1426987A3 (fr) * 2002-12-05 2006-08-23 Acktar Ltd. Electrodes pour condensateurs électrolytiques et leur méthode de fabrication
US7404887B2 (en) 2002-12-05 2008-07-29 Acktar, Ltd. Electrodes for electrolytic capacitors and method for producing them
US9978530B2 (en) * 2013-12-19 2018-05-22 Pacesetter, Inc. Method of nano-patterning a foil surface
US10957491B2 (en) 2016-09-16 2021-03-23 Japan Capacitor Industrial Co., Ltd. Electrolytic capacitor-specific electrode member and electrolytic capacitor
USD860134S1 (en) * 2017-07-10 2019-09-17 Nippon Chemi-Con Corporation Electrode foil for capacitor
USD860135S1 (en) * 2017-07-10 2019-09-17 Nippon Chemi-Con Corporation Electrode foil for capacitor
CN114141539A (zh) * 2021-12-08 2022-03-04 南通海星电子股份有限公司 一种弯曲疲劳强度良好低压电极箔的制备方法
WO2023103181A1 (fr) * 2021-12-08 2023-06-15 南通海星电子股份有限公司 Procédé de préparation de feuille d'électrode basse tension ayant une bonne résistance à la fatigue par flexion

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EP1233432A2 (fr) 2002-08-21
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EP1233432B1 (fr) 2011-12-14
US6611422B2 (en) 2003-08-26

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