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WO2024202916A1 - Condensateur et son procédé de fabrication - Google Patents

Condensateur et son procédé de fabrication Download PDF

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Publication number
WO2024202916A1
WO2024202916A1 PCT/JP2024/007684 JP2024007684W WO2024202916A1 WO 2024202916 A1 WO2024202916 A1 WO 2024202916A1 JP 2024007684 W JP2024007684 W JP 2024007684W WO 2024202916 A1 WO2024202916 A1 WO 2024202916A1
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WO
WIPO (PCT)
Prior art keywords
foil
terminal
piece
substrate
cathode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2024/007684
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English (en)
Japanese (ja)
Inventor
理帆グミラール 前田
悠汰 柏崎
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Nippon Chemi Con Corp
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Nippon Chemi Con Corp
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Filing date
Publication date
Application filed by Nippon Chemi Con Corp filed Critical Nippon Chemi Con Corp
Publication of WO2024202916A1 publication Critical patent/WO2024202916A1/fr
Anticipated expiration legal-status Critical
Pending 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
    • 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
    • H01G9/008—Terminals
    • 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
    • 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 disclosure relates to a capacitor comprising a cathode foil including a carbon layer and a method for making the same.
  • the capacitor includes an anode foil, a cathode foil, and a separator disposed between the anode foil and the cathode foil, and is capable of storing electricity.
  • a basic capacitor including a cathode foil made only of aluminum foil is known.
  • capacitors have been known that include a cathode foil including aluminum foil and a carbon layer formed on the aluminum foil (for example, Patent Document 1).
  • the carbon layer has the effect of increasing the capacitance of the capacitor and suppressing the generation of hydrogen gas, for example.
  • Electrode foils such as anode foil and cathode foil and drawer terminals are connected by a connection means such as stitch connection.
  • a stitch needle is inserted into the drawer terminal and electrode foil that are stacked on top of each other from the drawer terminal side.
  • the stitch needle tears the drawer terminal and electrode foil apart, forming a terminal hole and terminal piece in the drawer terminal, and a through hole and foil piece in the electrode foil.
  • the terminal piece protrudes from the back surface of the electrode foil through the through hole in the electrode foil.
  • the terminal piece and foil piece are pressed and stacked on the back surface of the electrode foil.
  • the terminal piece and foil piece or electrode foil are metallically joined or come into contact with each other by pressing, connecting the electrode foil to the drawer terminal.
  • the carbon layer has a lower static friction coefficient than metal foils such as aluminum foil, and cathode foils containing a carbon layer are more slippery than cathode foils consisting of only metal foil. Therefore, when connecting the terminal piece to the cathode foil, more specifically, when the overlapping terminal piece and foil piece press against the cathode foil, the foil piece moves from the base toward the tip of the foil piece. Therefore, the pressing force of the terminal piece and foil piece is dispersed in the pressing direction and the moving direction of the foil piece, so that with a cathode foil containing a carbon layer, the pressing force for pressing the terminal piece against the cathode foil is less than with a cathode foil consisting of only metal foil. This reduction in pressing force makes it difficult for the terminal piece to fix the cathode foil in place.
  • connection strength of the carbon layer to the terminal piece is electrically and physically weaker than the connection strength of the metal foil to the terminal piece.
  • an object of the present disclosure is to provide a stitch connection structure suitable for a cathode foil including, for example, a carbon layer.
  • a capacitor includes a cathode foil and an extraction terminal.
  • the cathode foil includes a foil body having a base foil and a carbon layer formed on the base foil, a through hole, and a foil piece extending from an edge of the through hole and overlapping the foil body.
  • the extraction terminal is connected to the cathode foil, and includes a flat portion placed on the terminal mounting surface of the cathode foil, and a terminal piece extending from the flat portion through the through hole and overlapping the surface of the cathode foil opposite the terminal mounting surface.
  • the foil piece has a base material exposed end surface at the outer edge where the base foil is exposed, and a portion of the base material exposed end surface of the foil piece arranged between the terminal piece and the foil body contacts the terminal piece.
  • the outer edge of the foil piece having the substrate exposed end surface may be positioned between the terminal piece and the foil body by irregularly meandering.
  • the exposed end surface of the substrate may be a cut surface formed by inserting a stitch needle.
  • a method for manufacturing a capacitor includes the steps of: making or preparing a cathode foil including a foil body having a base foil and a carbon layer formed on the base foil; arranging a flat portion of a pull-out terminal on a terminal mounting surface of the cathode foil; inserting a stitching needle from the flat portion side into the flat portion and the cathode foil to form a through hole and a foil piece extending from the edge of the through hole in the cathode foil, and forming a terminal piece extending from the flat portion and passing through the through hole in the pull-out terminal; and pressing the terminal piece and the foil piece against the surface of the cathode foil opposite the terminal mounting surface to connect the cathode foil and the pull-out terminal.
  • an exposed end surface of the substrate where the substrate foil is exposed is formed on the outer edge of the foil piece, and the foil piece before pressing includes an upright portion that extends in a direction that coincides with or nearly coincides with the insertion direction of the stitch needle, and in the process of pressing the terminal piece and the foil piece, the foil piece is crushed parallel or nearly parallel to the direction in which the upright portion extends, so that at least a portion of the exposed end surface of the substrate comes into contact with the terminal piece.
  • an irregular foil piece may be formed by inserting the stitching needle, and the exposed end surface of the substrate of the pressed foil piece may be positioned between the terminal piece and the foil body by irregularly meandering.
  • At least a portion of the exposed end surface of the substrate of the foil piece contacts the terminal piece, so that the substrate foil and the terminal piece are in direct contact without a carbon layer, and the contact between the metallic materials provides a stable physical and electrical connection.
  • the base foil and the terminal piece are in direct contact with each other at the outer edge of the foil piece, which reduces the relative movement between the terminal piece and the foil piece when pressed, thereby reducing the dispersion of the pressing force.
  • FIG. 4A and 4B are diagrams illustrating an example of a terminal connection portion of a capacitor according to an embodiment.
  • FIG. 2 is a cross-sectional view taken along line IIA-IIA in FIG. 11A to 11C are diagrams showing an example of a process for connecting a lead terminal to an electrode foil.
  • FIG. 13 is a diagram showing a first image of changes in shape of a lead terminal and a cathode foil when pressed.
  • FIG. 13 is a diagram showing a second image of changes in shape of the lead terminal and the cathode foil when pressed.
  • FIG. 1 shows an example of a terminal connection part of a capacitor according to an embodiment.
  • FIG. 2 shows a cross section along line IIA-IIA in FIG. 1.
  • the configurations shown in FIGS. 1 and 2 are examples, and the technology of the present disclosure is not limited to such configurations.
  • the terminal connection part includes the connection location where the drawer terminal 4 is connected to the cathode foil 6 by a stitch connection, that is, the connection part 10 and its surrounding area.
  • the connection part 10 is the area where the terminal piece 26 of the drawer terminal 4 is overlapped with at least the flat part 28 and the cathode foil 6, and where the drawer terminal 4 is connected to the cathode foil 6, and is the part shaded in FIG. 1.
  • FIG. 1 represents the outer edge of the flat part 28 of the drawer terminal 4, or the outer edge of the foil piece 20 of the cathode foil 6.
  • the cross section shown in FIG. 2 is an example of a central cross section passing through the center of the terminal piece 26.
  • B in FIG. 2 is an enlarged view of the area IIB shown in A in FIG. 2.
  • the dashed line shown in FIG. 2B represents the inclination of the foil piece 20 and the plane parallel to the surface of the cathode foil 6 outside the connection portion 10.
  • Capacitor 2 is an example of an electronic component, such as an electrolytic capacitor.
  • Capacitor 2 includes, for example, a capacitor element, an output terminal 4, an electrolyte, a sealing member such as insulating rubber, and an exterior case such as an aluminum case.
  • the capacitor element filled with electrolyte and part of the output terminal 4 are inserted inside the exterior case, and the sealing member is placed at the opening of the exterior case.
  • the output terminal 4 penetrates the sealing member and protrudes from the sealing member.
  • the capacitor element includes a cathode foil 6, an anode foil, and a separator.
  • the cathode foil 6, the anode foil, and the separator are stacked and wound to form a wound element, such that the separator is disposed between the cathode foil 6 and the anode foil.
  • the wound element forms the capacitor element.
  • the cathode foil 6 constitutes the cathode of the capacitor 2.
  • the cathode foil 6 is, for example, a strip-shaped foil, and includes a foil body 16 having a base foil 12 and a carbon layer 14, a through hole 18, and a foil piece 20.
  • the substrate foil 12 is the base metal of the cathode foil 6, and is, for example, a valve metal foil such as aluminum foil, tantalum foil, niobium foil, titanium foil, hafnium foil, zirconium foil, zinc foil, tungsten foil, bismuth foil, or antimony foil.
  • the surface of the substrate foil 12 has irregularities formed, for example, by etching, and the surface area of the substrate foil 12 is increased.
  • the surface of the substrate foil 12 may include, for example, tunnel-shaped or spongy etching pits, and these tunnel-shaped or spongy etching pits may form the irregularities.
  • the carbon layer 14 is disposed, for example, on both sides of the substrate foil 12.
  • the carbon layer 14 may be disposed on only one side of the substrate foil 12.
  • the carbon layer 14 partially penetrates inside the unevenness, and therefore adheres closely to and engages with the unevenness of the substrate foil 12. In other words, the carbon layer 14 has a surface shape that engages with the unevenness.
  • the carbon layer 14 is disposed on the outside of the substrate foil 12, and the cathode foil 6 has a two-layer structure of the substrate foil 12 and the carbon layer 14, or a three-layer structure in which the carbon layer 14 is disposed on both sides of the substrate foil 12.
  • the carbon layer 14 contains a carbon material as a main material, and further contains a binder and a dispersant as additives.
  • Carbon materials include activated carbon, carbon black, carbon nanohorns, amorphous carbon, natural graphite, artificial graphite, graphitized ketjen black, mesoporous carbon, and fibrous carbon.
  • Activated carbon is produced from natural plant tissues such as coconut shells, synthetic resins such as phenol, and fossil fuels such as coal, coke, and pitch.
  • Carbon black includes ketjen black, acetylene black, channel black, and thermal black.
  • Fibrous carbon includes carbon nanotubes and carbon nanofibers.
  • Carbon nanotubes may be single-walled carbon nanotubes, which have one graphene sheet, or multi-walled carbon nanotubes (MWCNTs), which have two or more graphene sheets rolled coaxially to form multiple tube walls.
  • MWCNTs multi-walled carbon nanotubes
  • the carbon material is preferably carbon black, which is spherical carbon.
  • carbon black which is spherical carbon black with an average primary particle diameter of 100 nanometers or less
  • the carbon layer 14 becomes dense.
  • carbon black with a particle diameter smaller than the opening diameter of the unevenness formed on the surface of the cathode foil 6 by etching the carbon black easily penetrates deep into the unevenness, the carbon layer 14 adheres closely to the base foil 12 of the cathode foil 6, and the interface resistance between the carbon layer 14 and the base foil 12 is easily reduced.
  • the carbon material is preferably a mixture containing spherical carbon and graphite.
  • the graphite is, for example, natural graphite, artificial graphite, or graphitized ketjen black, and has a shape such as a scale-like, scale-like, lump-like, earth-like, spherical, or flaky shape.
  • the graphite is preferably flaky or flaky, and the aspect ratio of the short diameter to the long diameter of the graphite is preferably in the range of 1:5 to 1:100.
  • Flake-like or thin-film graphite with the aspect ratio described above can push spherical carbon into irregularities such as etching pits, and part of the carbon layer 14 can be formed even inside the etching pits. Therefore, the anchor effect allows the carbon layer 14 to adhere firmly to the base foil 12.
  • the mass ratio of graphite to the mixture of graphite and spherical carbon is, for example, in the range of 25% to 90%.
  • the binder is a resin-based binder such as styrene butadiene rubber, polyvinylidene fluoride, or polytetrafluoroethylene, which binds the carbon material.
  • the dispersant is, for example, sodium carboxymethylcellulose.
  • the foil piece 20 extends from the edge 22 of the through hole 18 and is folded back at the edge 22.
  • the foil piece 20 is folded back to overlap the foil body 16.
  • the foil piece 20 has the substrate foil 12 and the carbon layer 14, like the foil body 16, and has a substrate exposed end surface 24 at the outer edge.
  • the substrate exposed end surface 24 is not covered with the carbon layer 14, and the substrate foil 12 (i.e., the base metal) is exposed.
  • the substrate exposed end surface 24 for example, meanders irregularly (randomly) and enters and exits the connection portion 10. Therefore, in the portion where the substrate exposed end surface 24 enters the connection portion 10 (the first portion of the substrate exposed end surface 24), the substrate exposed end surface 24 contacts the terminal piece 26 of the drawer terminal 4.
  • the substrate exposed end surface 24 separates from the terminal piece 26 of the drawer terminal 4 and is exposed. That is, a portion of the substrate exposed end surface 24 is disposed between the terminal piece 26 and the foil body 16 and contacts the terminal piece 26.
  • the substrate exposed end surface 24 is, for example, a cut surface formed by the insertion of a stitch needle 50 (FIG. 3).
  • the foil piece 20 is inclined at an inclination angle ⁇ relative to the surface of the cathode foil 6 outside the connection portion 10.
  • the substrate exposed end surface 24 has, for example, an inclination angle smaller than the inclination angle ⁇ .
  • the inclination angle of the substrate exposed end surface 24 may be a constant value or may vary.
  • the inclination angle of the substrate exposed end surface 24 gradually decreases, for example, from the inclination angle ⁇ toward 0 degrees, as shown in FIG. 2B.
  • the anode foil constitutes the anode of the capacitor 2.
  • the anode foil is, for example, the valve metal foil described above, and is a strip-shaped foil.
  • An enlarged surface portion having a porous structure is formed on the surface of the anode foil.
  • the porous structure is, for example, formed by tunnel-shaped pits, spongy pits, or gaps between densely packed powder particles, formed by etching.
  • the surface of the enlarged surface portion includes a dielectric oxide film formed by chemical conversion treatment.
  • the anode foil is connected to the anode side lead terminal by stitch connection or other connection means.
  • the separator is disposed between the anode foil and the cathode foil 6 to prevent short circuits between the anode foil and the cathode foil 6.
  • the separator is an insulating material and includes kraft as a separator material, and may include other separator materials such as manila, esparto, hemp, rayon, cellulose, and mixtures thereof.
  • the drawer terminal 4 is formed of a conductive metal such as aluminum.
  • the drawer terminal 4 is, for example, a lead terminal including a lead wire, a terminal portion, and a terminal piece 26.
  • the terminal portion is made of an aluminum wire and is composed of a roughly cylindrical round bar portion and a flat portion 28 formed by pressing one end of the aluminum wire. Between the round bar portion and the flat portion 28, a sloping portion is formed whose thickness gradually decreases from the thickness of the round bar portion to the thickness of the flat portion 28.
  • the lead wire is, for example, made of a metal wire, and is connected to the round bar portion by arc welding.
  • the flat portion 28 is overlaid on the terminal mounting surface of the cathode foil 6, and includes a terminal hole 30.
  • the terminal hole 30 is positioned so as to overlap the through hole 18.
  • the terminal piece 26 is formed on the flat portion 28, extends from the edge of the terminal hole 30 of the flat portion 28, passes through the through hole 18, and is brought out to the side opposite the terminal mounting surface of the cathode foil 6 (i.e., the foil surface on which the flat portion 28 is placed), and is pressed against the opposite surface of the cathode foil 6.
  • the lead terminal 4 is connected to the cathode foil 6 at the connection portion 10 by sandwiching the cathode foil 6 between the flat portion 28 and the bent terminal piece 26.
  • the direction of the pressing force during stitch connection (hereinafter referred to as the "pressing direction") is, for example, parallel to the penetration direction of the through hole 18.
  • the pressing direction As the inclination angle of the substrate exposed end face 24 decreases toward 0 degrees, the angle between the substrate exposed end face 24 and the pressing direction approaches a right angle. Therefore, the pressing force applied to the substrate exposed end face 24 during stitch connection increases.
  • Contact between the valve metal of the terminal piece 26 and the substrate exposed end face 24 suppresses slippage or relative movement of the cathode foil 6 and strengthens the physical and electrical connection between the substrate exposed end face 24 and the terminal piece 26.
  • the electrolyte may be an electrolytic solution, a gel electrolyte, a solid electrolyte containing a conductive polymer, or the like.
  • a so-called hybrid electrolytic capacitor may be formed by using an electrolyte that is an electrolytic solution or a gel electrolyte and a solid electrolyte that contains a conductive polymer.
  • the electrolyte of an electrolytic capacitor contains a solvent and a solute dissolved in the solvent, and may contain additives as necessary.
  • the solvent may be either a protic polar solvent or an aprotic polar solvent.
  • Protic polar solvents include, for example, monohydric alcohols, polyhydric alcohols, oxyalcohol compounds, water, etc.
  • Abprotic polar solvents include, for example, sulfones, amides, lactones, cyclic amides, nitriles, oxides, etc.
  • the solute contains anion and cation components, and is typically an organic acid or a salt thereof, an inorganic acid or a salt thereof, or a complex compound of an organic acid and an inorganic acid or an ionically dissociable salt thereof, and may be used alone or in combination of two or more.
  • An acid that becomes an anion and a base that becomes a cation may be added separately to the electrolyte as solute components.
  • a conductive polymer is contained in the electrolyte layer.
  • the conductive polymer is a conjugated polymer or a doped conjugated polymer.
  • the conjugated polymer may be any known conjugated polymer without any particular limitations. Examples of the conjugated polymer include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, polyphenylenevinylene, polyacene, polythiophenevinylene, etc., and poly(3,4-ethylenedioxythiophene) is preferred.
  • the conjugated polymer may be used alone, or two or more types may be combined, or it may be a copolymer of two or more types of monomers.
  • FIG. 3 shows an example of the process of connecting the lead terminal to the electrode foil in the manufacturing process of a capacitor.
  • FIG. 4 shows a first image of the shape change of the lead terminal and the cathode foil when pressed.
  • FIG. 5 shows a second image of the shape change of the lead terminal and the cathode foil when pressed.
  • the images of the shape change shown in FIG. 4 and FIG. 5 are examples.
  • the dashed line P shown in FIG. 4 and FIG. 5 represents the reference position, and the positions on the dashed line P in FIG. 4 and FIG. 5 are the same positions.
  • the dashed line J shown in FIG. 4C and FIG. 5C represents that the terminal piece 26 is directly connected to the flat portion 28.
  • the configurations shown in FIG. 3, FIG. 4, and FIG. 5 are examples, and the technology of the present disclosure is not limited to the configurations shown in FIG. 3, FIG. 4, and FIG. 5.
  • the manufacturing process of the capacitor 2 is an example of a manufacturing method of the capacitor of the present disclosure, and includes, for example, a process of making the anode foil, a process of making the cathode foil 6, a process of making the separator, a process of making the drawer terminal 4, a process of connecting the drawer terminal 4 to the electrode foil (hereinafter referred to as the "terminal connection process"), a process of making the capacitor element, and a process of encapsulating the capacitor element.
  • an enlarged surface portion having a porous structure is formed on the surface of the valve metal foil described above, and a dielectric oxide film is formed on the surface of the valve metal foil on which the enlarged surface portion has been formed by chemical conversion treatment.
  • the enlarged surface portion is formed by direct current etching, alternating current etching, or by vapor deposition or sintering of metal particles onto the valve metal foil.
  • direct current etching or alternating current etching a direct current or alternating current is typically applied to the valve metal foil immersed in an acidic aqueous solution containing halogen ions, such as hydrochloric acid.
  • the valve metal foil on which the dielectric oxide film has been formed is cut to produce and prepare the anode foil.
  • the surface of the valve metal foil described above is etched to form irregularities, thereby producing the base foil 12.
  • the etching of the cathode foil 6 may be the same as that of the anode foil, or it may be different.
  • a carbon layer 14 is formed on the base foil 12, and the base foil 12 and the carbon layer 14 are cut into strips to produce and prepare the cathode foil 6 before the through holes 18 and foil pieces 20 are formed.
  • the carbon layer 14 is formed, for example, as follows.
  • the carbon material, binder, and dispersant described above are added to a diluent, and these are mixed by a dispersion process such as a mixer, jet mixing (jet collision), ultracentrifugation, or ultrasonic treatment to form a slurry.
  • the diluent is, for example, alcohol, a hydrocarbon solvent, an aromatic solvent, an amide solvent, water, or a mixture of these.
  • the alcohol is, for example, methanol, ethanol, or 2-propanol.
  • the amide solvent is, for example, N-methyl-2-pyrrolidone (NMP) or N,N-dimethylformamide (DMF).
  • the slurry is applied to the base foil 12, the solvent is evaporated to form the carbon layer 14, and the carbon layer 14 is pressed.
  • the press can, for example, force the carbon material into the pores of the unevenness, or, if the carbon material is larger than the pores of the unevenness, can deform the carbon material along the uneven surface of the unevenness. Forcing the carbon material into the pores of the unevenness or deforming the carbon material along the uneven surface of the unevenness improves, for example, the adhesion and fixation between the carbon layer 14 and the base foil 12. If the carbon material contains graphite, the press aligns the graphite and deforms the graphite to follow the unevenness of the base foil 12.
  • the press forces the spherical carbon into the inside of the unevenness when the graphite is pressed against the unevenness, and adheres the slurry to the base foil 12, resulting in the carbon layer 14 adhering to the base foil 12.
  • the carbon material is only spherical carbon, for example, the spherical carbon with an average primary particle size of 100 nanometers or less penetrates the unevenness, reducing the interface resistance between the carbon layer 14 and the substrate foil 12.
  • the static friction coefficient of the surface of the carbon layer 14 is improved, making it less likely to slip when the terminal piece 26 is pressed against the cathode foil 6, and a stitch connection with stable connectivity is obtained.
  • the separator components described above are cut to produce and prepare the separator.
  • one end of the roughly cylindrical round bar section made of the conductive metal described above is pressed, for example, to form the flat section 28.
  • the side of the round bar section where the flat section 28 is not formed is connected to a lead wire by arc welding or the like, to manufacture and prepare the drawer terminal 4 before the terminal piece 26 and terminal hole 30 are formed.
  • the lead-out terminal 4 is connected to the cathode foil 6 and the anode foil, respectively.
  • the cathode foil 6 before stitch connection is placed on a first mold 42 such as a lower mold, and the drawer terminal 4 before stitch connection (specifically, the flat portion 28) is placed on the upper surface of the cathode foil 6.
  • a second mold 44 such as an upper mold is placed on the upper surface of the drawer terminal 4 (specifically, the flat portion 28). Therefore, the cathode foil 6 and the drawer terminal 4 are sandwiched between the first mold 42 and the second mold 44 and are held by the first mold 42 and the second mold 44.
  • the first mold 42 has a through hole 46
  • the second mold 44 has a through hole 48.
  • the through hole 48 is smaller than the through hole 46 and is positioned directly above the through hole 46.
  • the stitch needle 50 is positioned above the through hole 48.
  • the stitch needle 50 has, for example, a cylindrical shaft 52 and an acute-angled, quadrangular pyramidal tip 54.
  • the bottom surface of the tip 54 is, for example, a square or nearly square with a side length of L
  • the cross section of the shaft 52 is, for example, a circle or nearly circular with a diameter of L or less.
  • the stitch needle 50 is moved by a distance M in the direction of the block arrow shown in FIG. 3A, and as shown in FIG. 3B, the stitch needle 50 is inserted into the drawer terminal 4 and the cathode foil 6 from the drawer terminal 4 side up to an insertion position 56.
  • the insertion position 56 is set, for example, to a position overlapping with the shaft portion 52, or at the boundary position between the shaft portion 52 and the tip portion 54.
  • the stitch needle 50 cuts through the drawer terminal 4 and the cathode foil 6, forming the terminal piece 26 and the terminal hole 30 in the drawer terminal 4, and the through hole 18 and the foil piece 20 in the cathode foil 6.
  • the insertion of the stitch needle 50 tears the cathode foil 6 irregularly (randomly), forming the foil pieces 20 of irregular size and shape.
  • the foil pieces 20 formed by inserting the stitch needle 50 into the cathode foil 6 are deformed so as to expand in a direction away from the through hole 18.
  • the size of the through hole 46 of the first die 42 is set so that the foil piece 20 does not touch the inside of the through hole 46 and expand excessively. In this way, the size and shape of the foil piece 20 can be made uniform.
  • the through hole 46 of the first die 42 is deformed so that the foil piece 20 expands in the direction away from the through hole 18, the size and shape are not adjusted, and foil pieces 20 of irregular size and shape are formed.
  • the substrate foil 12 is exposed at the outer edge of the foil piece 20, forming the substrate exposed end surface 24.
  • the lowered stitch needle 50 is raised and removed from the lead terminal 4 and the cathode foil 6.
  • the terminal piece 26 after the stitch needle 50 is inserted and before it is pressed (hereinafter simply referred to as the "terminal piece 26 before pressing") includes an upright portion 58 that extends in a direction that is the same as or almost the same as the insertion direction of the stitch needle 50 (hereinafter simply referred to as the "extension direction”), as shown in FIG. 3B.
  • the foil piece 20 after the stitch needle 50 is inserted and before it is pressed (hereinafter simply referred to as the "foil piece 20 before pressing”) includes an upright portion 60 that extends in the extension direction.
  • the amount of deformation of the terminal piece 26 and the foil piece 20 is suppressed when the stitch needle 50 is inserted, and a part of the terminal piece 26 and the foil piece 20 is arranged almost perpendicular to the flat portion 28 of the pull-out terminal 4.
  • the shape of the stitch needle 50, the movement distance M of the stitch needle 50, the insertion speed of the stitch needle 50, or the thickness T of the flat portion 28, etc. are adjusted.
  • the uprights 58, 60 may be formed without any special adjustments.
  • the terminal piece 26 formed becomes larger, and the terminal piece 26 becomes more likely to warp away from the terminal hole 30.
  • the foil piece 20, which is thinner than the terminal piece 26, warps according to the terminal piece 26.
  • length L the length of the side when cross-sectioned perpendicular to the length direction of the stitch needle 50
  • the foil piece 20 and terminal piece 26 before pressing become smaller, and the upright portions 58, 60 become more likely to be formed.
  • the moving distance M becomes shorter, the length of the side of the stitch needle 50 at the insertion position 56 becomes smaller, and the upright portions 58, 60 become more likely to be formed.
  • the thickness T of the flat portion 28 affects the direction in which the terminal piece 26 stretches.
  • the side length L of the stitch needle 50 may be adjusted to, for example, 0.6 to 0.8 millimeters (hereinafter referred to as "mm").
  • the ratio of the side length L of the stitch needle 50 to the thickness T of the flat portion 28 (for example, 0.35 mm) (hereinafter referred to as the "L/T ratio") may be adjusted to, for example, 1.7 to 2.3.
  • the ratio of the side length L of the stitch needle 50 to the thickness of the cathode foil 6 (for example, 0.02 mm) may be adjusted to, for example, 30 to 40.
  • the forming die 62 has, for example, a flat pressing surface on its upper side, and is positioned below the through-hole 46.
  • the forming die 62 is raised in the direction of the block arrow shown in FIG. 3B, and the pressing surface presses the draw-out terminal 4 and the cathode foil 6, particularly the terminal piece 26 and the foil piece 20, from the cathode foil 6 side.
  • the terminal piece 26 and the foil piece 20 are sandwiched between the second die 44 and the forming die 62.
  • the terminal piece 26 and the foil piece 20 are folded back by the pressure, and the draw-out terminal 4 is connected to the cathode foil 6.
  • the substrate foil 12 exposed in the non-peripheral portion may be connected to the terminal piece 26, which may suppress the relative movement of the cathode foil 6 and increase the physical and electrical connection between the foil piece 20 and the terminal piece 26.
  • the outer edge of the foil piece 20 is positioned at the connection portion 10 with the terminal piece 26, and the exposed end surface 24 of the substrate contacts and connects to the terminal piece 26, as shown in FIG. 4C.
  • the tip of the foil piece 20 protrudes from the terminal piece 26, and the exposed end surface 24 of the substrate is positioned away from the terminal piece 26, as shown in FIG. 5C.
  • the exposed end surface 24 of the substrate meanders irregularly (randomly) as it enters and exits the connection portion 10.
  • the terminal connection process for the anode foil may be the same as or different from the terminal connection process for the cathode foil 6.
  • a first separator is placed between the anode foil and the cathode foil 6, and a second separator is placed on the outside of the anode foil or the cathode foil 6.
  • the anode foil, the cathode foil 6, and the first and second separators are wound together to manufacture the capacitor element.
  • the capacitor element impregnated with an electrolyte such as an electrolytic solution is inserted inside the exterior case, and then a sealing material is attached to the opening of the exterior case to create the capacitor 2.
  • the substrate exposed end surface 24 of the foil piece 20 meanders irregularly.
  • the outer edge of the foil piece 20 having the substrate exposed end surface 24 is located in a portion that is disposed between the terminal piece 26 and the cathode foil 6 and in a portion where the terminal piece 26 and the cathode foil 6 are not laminated, and the substrate exposed end surface 24 partially contacts the terminal piece 26.
  • the substrate foil 12 and the terminal piece 26 are in direct contact without the carbon layer 14, and the contact between the metallic materials stabilizes the physical and electrical connection.
  • the exposed end surface 24 of the substrate that is exposed by the insertion of the stitch needle 50 is used for contact between metal-based materials, so an increase in the number of steps in the terminal connection process can be avoided.
  • a stitch connection suitable for the properties of the cathode foil 6 including the carbon layer 14 can be realized, and the stability or reliability of the capacitor 2 including the cathode foil 6 including the carbon layer 14 can be improved.
  • the carbon layer 14 is formed by applying carbon to the base foil 12 on which the enlarged surface portion is formed, and pressing the carbon into the enlarged surface portion.
  • the adhesion between the base foil 12 and the carbon layer 14 can be improved while improving the connectivity with the drawer terminal 4. If an attempt is made to peel off the carbon layer 14 in the intended connection portion between the cathode foil 6 and the drawer terminal 4 in advance, the pressed carbon penetrates into the inside of the enlarged surface portion, so that the carbon layer 14 in the intended connection portion cannot be peeled off entirely. The carbon layer 14 remaining in the intended connection portion reduces the connectivity between the cathode foil 6 and the drawer terminal 4.
  • the carbon layer 14 in the intended connection portion can be removed by peeling.
  • the removal of the carbon layer 14 in the intended connection portion stabilizes the connectivity between the cathode foil 6 and the drawer terminal 4, but reduces the adhesion between the base foil 12 and the carbon layer 14. According to this embodiment, it is possible to improve the adhesion between the substrate foil 12 and the carbon layer 14, while at the same time improving the stability or reliability of the capacitor 2 having the cathode foil 6 including the carbon layer 14 by exposing the substrate foil 12.
  • the sample of the embodiment was compared with the samples of the comparative examples 1 to 5.
  • the sample of the example is a connection between the cathode foil 6 and the lead terminal 4 used in the capacitor 2 of the embodiment described above, where the flat portion 28 of the lead terminal 4 has a thickness T of 0.35 mm and the cathode foil 6 has a thickness of 0.02 mm.
  • a stitch needle 50 with a side length L of 0.8 mm was used in the terminal connection process.
  • the sample of Comparative Example 1 includes a cathode foil 6 having a base foil 12 and a carbon layer 14 (hereinafter referred to as "carbon-containing foil” in the Examples and Comparative Examples), the flat portion 28 has a thickness T of 0.35 mm, and the cathode foil 6 has a thickness of 0.02 mm.
  • a stitch needle 50 having a side length L of 1.0 mm was used in the terminal connection process. Except for the stitch needle 50, the terminal connection process in Comparative Example 1 is the same as the terminal connection process in the Examples. In other words, a terminal hole 30 larger than that of the drawer terminal 4 of the Examples was formed in the drawer terminal 4 of Comparative Example 1.
  • the samples according to Comparative Example 2 and Comparative Example 3 include a cathode foil (hereinafter referred to as "aluminum foil" in the Comparative Examples) that does not include a carbon layer 14, and the flat portion 28 has a thickness T of 0.35 mm.
  • aluminum foil hereinafter referred to as "aluminum foil” in the Comparative Examples
  • a stitch needle 50 having a side length L of 0.8 mm was used in the terminal connection process.
  • a stitch needle 50 having a side length L of 1.0 mm was used in the terminal connection process.
  • the sample according to Comparative Example 4 includes a carbon-containing foil, the flat portion 28 having a thickness T of 0.29 mm, and the cathode foil 6 having a thickness of 0.02 mm.
  • a stitch needle 50 having a side length L of 0.8 mm was used in the terminal connection process.
  • the sample of Comparative Example 5 includes a carbon-containing foil, the flat portion 28 has a thickness T of 0.35 mm, and the cathode foil 6 has a thickness of 0.02 mm.
  • a stitch needle 50 having a side length L of 0.64 mm was used in the terminal connection process. Except for the stitch needle 50, the terminal connection process in Comparative Example 5 is the same as the terminal connection process in the Examples.
  • the terminal connection of the sample according to the embodiment had an appearance similar to that of the terminal connection shown in FIG. 1. That is, the exposed end surface 24 of the substrate formed on the outer edge of the foil piece 20 meandered irregularly and entered and exited the connection part 10. However, in the terminal connection of the sample according to the comparative example 1, the exposed end surface 24 of the substrate formed on the outer edge of the foil piece 20 was exposed away from the terminal piece 26. Comparing the embodiment and the comparative example 1, it was confirmed that by adjusting the size of the terminal hole 30 formed by the stitch needle 50, the exposed end surface 24 of the substrate can be made to meander irregularly, and at least a part of the exposed end surface 24 of the substrate can be brought into contact with and connected to the terminal piece 26.
  • Table 1 shown below shows the results of confirming the contact resistance and connection strength of the sample according to Example 1 and the samples according to Comparative Examples 1 to 5.
  • the contact resistance and connection strength are shown as average values of five samples for each of the Example and Comparative Examples.
  • the contact resistance is the resistance value between the lead terminal 4 and the cathode foil, and is measured by a resistance meter.
  • connection strength was measured by fixing the cathode foil 6, and moving the tip of the lead wire of the lead terminal 4 protruding from the end of the cathode foil 6 at a speed of 0.5 centimeters/second in a direction in which the lead terminal 4 moves away from the surface of the cathode foil 6, while continuously measuring the stress with a load cell until the connection part 10 is peeled off from the cathode foil 6, and the largest force (N) was taken as the connection strength.
  • Comparative Example 5 in which the side length L of the stitch needle 50 is set to 0.64 mm, which is smaller than 0.8 mm in the Example, in order to make the terminal piece 26 smaller, the contact resistance of Comparative Example 5, in which the side length L of the stitch needle 50 is set to 0.64 mm, which is smaller than 0.8 mm in the Example, is increased to the same extent as the contact resistance of Comparative Example 1, in which the side length L of the stitch needle 50 is 1.0 mm.
  • the size of the terminal piece 26 is affected not only by the size of the stitch needle 50, but also by the thickness T of the flat part 28 of the pull-out terminal 4 that forms the terminal piece 26.
  • the terminal piece 26 tends to become larger because the material constituting the terminal piece 26 increases, and conversely, when the thickness T of the flat portion 28 is thin, the terminal piece 26 tends to become smaller, and the thickness T of the flat portion 28 affects the contact resistance.
  • the contact resistance was high in Comparative Example 4, in which the thickness T of the flat portion 28 was thinned to 0.29 mm, which is smaller than the 0.35 mm in the embodiment.
  • the capacitor element, the drawer terminal 4, the outer case, the sealing material, the electrolyte, etc. are not limited to those described in the embodiment. These materials may be other materials used in aluminum electrolytic capacitors or similar capacitors.
  • the drawer terminal 4 may be a tab terminal, and the sealing material may be a phenol laminate plate with an external terminal attached. After the capacitor element is impregnated with the electrolyte, the drawer terminal 4 derived from the capacitor element may be connected to the external terminal of the sealing material, or the capacitor element and the sealing material may be inserted into the outer case and sealed with the sealing material.
  • the capacitor element may be, for example, a laminated element in which a plurality of flat anode foils, cathode foils 6, and separators are laminated.
  • the material of the carbon layer 14 is not limited to those described in the embodiment.
  • the material forming the carbon layer 14 may be any conductive material containing carbon.
  • the state of adhesion or engagement of the carbon layer 14 to the substrate foil 12 is not limited to those described in the embodiment.
  • the drawer terminal 4 is placed on the cathode foil 6, the stitch needle 50 pierces the drawer terminal 4 and the cathode foil 6 from above, and the forming die 62 presses the drawer terminal 4 and the cathode foil 6 from below.
  • the drawer terminal 4, the cathode foil 6, the stitch needle 50, and the forming die 62 may be arranged upside down or rotated by any angle with respect to the arrangement described in the embodiments, for example.
  • connection portion 10 is formed by inserting the stitch needle 50 into the drawer terminal 4 and the cathode foil 6 while both the cathode foil 6 and the drawer terminal 4 are held between the first die 42 and the second die 44, and pressing the terminal piece 26 and the foil piece 20, but this is not limited to the above.
  • connection portion 10 may be formed by inserting the stitch needle 50 into the drawer terminal 4 and the cathode foil 6 while both the cathode foil 6 and the drawer terminal 4 are held between the first die 42 and the second die 44, releasing the holding by the first die 42 and the second die 44, and sending the cathode foil 6 and the drawer terminal 4 to the next process, where the connection portion 10 is formed by pressing the drawer terminal 4 and the foil piece 20 with a mold having a flat pressing surface that is sandwiched between the side on which the foil piece 20 and the terminal piece 26 are formed and the side on which the drawer terminal 4 is formed.
  • the stitch needle 50 has a tip 54 that is acute and pyramidal.
  • the tip 54 may be conical or pyramidal in shape.
  • the tip 54 may be regular or non-regular.
  • a regular pyramid is defined as a pyramid having a regular polygonal base with a perpendicular line from the apex passing through the center of the base.
  • a non-regular pyramid is defined as a pyramid other than a regular pyramid.
  • the tip 54 may also have an irregular cross-sectional shape in a cross section parallel to the base. An even more irregular foil piece 20 may be formed by the insertion of a tip 54 having an irregular shape.
  • upright portion 58 and upright portion 60 are formed, but either one may be formed.
  • the insertion position 56 is set at a position overlapping with the shaft portion 52 or at the boundary between the shaft portion 52 and the tip portion 54. However, the insertion position 56 may be set at a position overlapping with the tip portion 54.
  • the stitch needle 50 may be inserted into the lead-out terminal 4 and the cathode foil 6 up to the insertion position 56, and a through hole 18 and a terminal hole 30 may be formed according to the size of the cross section of the insertion position 56.
  • the length of the side in the cross section of the insertion position 56 may be set as the "side length L" instead of the length of the side in the bottom surface of the tip portion 54, and the length of the side in the cross section of the insertion position 56 may be adjusted so as to form the upright portions 58, 60 and the irregular foil pieces 20.
  • the technology disclosed herein is useful for connecting cathode foils containing carbon layers to lead terminals and for capacitors containing these.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Fixed Capacitors And Capacitor Manufacturing Machines (AREA)

Abstract

Un condensateur (2) comprend une feuille de cathode (6) et une borne de sortie (4). La feuille de cathode comprend : un corps de feuille (16) qui a une feuille de substrat (12) et une couche de carbone (14) formée sur ladite feuille de substrat ; un trou traversant (18) ; et une pièce de feuille (20) qui s'étend à partir d'une partie bord (22) du trou traversant et qui est superposée sur le corps de feuille. La borne de sortie est connectée à la feuille de cathode et comprend : une partie plate (28) qui est montée sur une surface de montage de borne de la feuille de cathode ; et une pièce de borne (26) qui s'étend à partir de la partie plate et passe à travers le trou traversant de façon à être superposée sur la surface opposée de la feuille de cathode à partir de la surface de montage de borne. La pièce de feuille a, au niveau d'un bord externe de celle-ci, une surface d'extrémité de substrat exposée (24) où la feuille de substrat est exposée, et une partie de la surface d'extrémité de substrat exposée de la pièce de feuille qui est placée entre la pièce de borne et le corps de feuille est en contact avec la pièce de borne.
PCT/JP2024/007684 2023-03-28 2024-03-01 Condensateur et son procédé de fabrication Pending WO2024202916A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010116668A1 (fr) * 2009-03-31 2010-10-14 日本ケミコン株式会社 Condensateur électrolytique et procédé de fabrication
JP2018120939A (ja) * 2017-01-25 2018-08-02 日本ケミコン株式会社 コンデンサおよびその製造方法
JP2023067187A (ja) * 2021-10-29 2023-05-16 パナソニックＩｐマネジメント株式会社 電解コンデンサおよびその製造方法

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Publication number Priority date Publication date Assignee Title
JPH0547461Y2 (fr) * 1989-09-06 1993-12-14
US20220415582A1 (en) * 2019-12-18 2022-12-29 Nippon Chemi-Con Corporation Electrolytic capacitor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010116668A1 (fr) * 2009-03-31 2010-10-14 日本ケミコン株式会社 Condensateur électrolytique et procédé de fabrication
JP2018120939A (ja) * 2017-01-25 2018-08-02 日本ケミコン株式会社 コンデンサおよびその製造方法
JP2023067187A (ja) * 2021-10-29 2023-05-16 パナソニックＩｐマネジメント株式会社 電解コンデンサおよびその製造方法

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