WO2024034640A1

WO2024034640A1 - Capacitor and manufacturing method therefor

Info

Publication number: WO2024034640A1
Application number: PCT/JP2023/029104
Authority: WO
Inventors: 秀之大道; 卓哉深山; 航太福島; 圭祐田邉; 理帆グミラール前田
Original assignee: 日本ケミコン株式会社
Priority date: 2022-08-10
Filing date: 2023-08-09
Publication date: 2024-02-15

Abstract

The purpose of the present disclosure is to provide a stitching connection structure suited to cathode foil that includes a carbon layer, for example.　Cathode foil (6) includes base-material foil (12) and a carbon layer (14) formed onto the base-material foil, and has a through hole (18). A lead terminal (4) includes: a flat section (32) that is carried on a terminal-carrying surface of the cathode foil; and a terminal strip (34) that is formed on the flat section and that passes through the through hole and is led out to the surface on the opposite side from the terminal-carrying surface of the cathode foil and is folded over. The lead terminal is connected to the cathode foil by the cathode foil being sandwiched between the flat section and the terminal strip. The cathode foil has, at a tip-end portion of a foil strip (20) extending from an edge portion (22) of the through hole, a base-material exposed surface (28) in which the base-material foil is exposed. The base-material exposed surface is disposed between a root (38) and a tip (40) of the terminal strip, and connects with the terminal strip.

Description

Capacitor and its manufacturing method

The present disclosure relates to a capacitor including a cathode foil including a carbon layer and a method for manufacturing the same.

A capacitor includes an anode foil, a cathode foil, and a separator placed between the anode foil and the cathode foil, and is capable of storing electricity. Regarding such capacitors, a basic capacitor including a cathode foil made only of aluminum foil is known. Furthermore, in recent years, a capacitor including a cathode foil including an aluminum foil and a carbon layer formed on the aluminum foil has been known (for example, Patent Document 1). The carbon layer has the effect of increasing the capacitance of the cathode foil, for example.

Japanese Patent Application Publication No. 2006-80111

Electrode foils such as anode foils and cathode foils and lead terminals are connected by connection means such as stitch connections. In the stitch connection process for forming a stitch connection, a stitch needle is inserted through the overlapping lead terminal and electrode foil from the lead terminal side, a terminal hole and a terminal piece are formed in the lead terminal, and a through hole and a terminal piece are formed in the electrode foil. Foil pieces are formed. The terminal piece passes through the through hole in the electrode foil and protrudes from the back surface of the electrode foil. The terminal piece and foil piece are pressed and stacked on the back side of the electrode foil. As a result, a stitched connection portion is formed, and the electrode foil and the lead terminal are connected.

Incidentally, the carbon layer has a lower coefficient of static friction than metal foil such as aluminum foil, and the cathode foil containing the carbon layer is more slippery than the cathode foil consisting only of metal foil. Therefore, when connecting the terminal piece to the cathode foil, more specifically, when the terminal piece and the foil piece press the cathode foil, the foil piece moves from the base portion 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 with a cathode foil containing a carbon layer, the terminal piece is pressed against the cathode foil more than with a cathode foil made only of metal foil. The pressing force for this decreases. Due to the reduced pressing force, there is a problem that it is difficult to fix the cathode foil with the terminal piece.

In addition, when the terminal piece and the foil piece press the cathode foil, if the contact area between the cathode foil and the terminal piece is not fixed, the pressed part of the cathode foil will be difficult to stretch, and the base metal of the cathode foil will move away from the carbon layer. In other words, the metal foil) is difficult to expose. There is a problem in that the connection force of the carbon layer to the terminal piece is electrically and physically lower than the connection force of the metal foil to the terminal piece.

Therefore, an object of the present disclosure is to provide a stitch connection structure suitable for, for example, a cathode foil including a carbon layer.

According to the first aspect of the present disclosure, the capacitor includes a cathode foil and a lead terminal. The cathode foil includes a base foil and a carbon layer formed on the base foil, and has a through hole. The lead-out terminal has a flat portion placed on the terminal placement surface of the cathode foil, and is formed on the flat portion and led out through the through hole to a side opposite to the terminal placement surface of the cathode foil. and a bent terminal piece, and is connected to the cathode foil by sandwiching the cathode foil between the flat part and the terminal piece. The cathode foil has a base material exposed surface where the base material foil is exposed at the tip of the foil piece extending from the edge of the through hole, and the base material exposed surface is connected to the base of the terminal piece. The base material exposed surface connects with the terminal piece.

In the above capacitor, the exposed surface of the base material may intersect with the penetrating direction of the through hole.

In the above capacitor, in a central cross section passing through a central portion of the terminal piece, an angle between the penetrating direction of the through hole and the exposed surface of the base material may be 45 degrees or more and 90 degrees or less.

In the above capacitor, the exposed base surface may have an exposed length greater than the thickness of the cathode foil in a central cross section passing through the central portion of the terminal piece.

In the above capacitor, the lead terminal may be connected to the cathode foil at a stitch connection portion. The extraction terminal may have a metal surface portion and a hardened surface portion that is harder than the metal surface portion. The metal surface portion may contact the substrate foil in a first region of the stitch connection, and the hardened surface portion may be laminated to the carbon layer in a second region of the stitch connection. .

According to a second aspect of the present disclosure, a method for manufacturing a capacitor includes a step of producing or preparing a cathode foil that includes a base foil and a carbon layer formed on the base foil, and has a foil removal hole. a step of arranging a flat part of the drawer terminal on the cathode foil so as to cover the foil removal hole, and inserting the stitch needle from the drawer terminal side so that the stitch needle passes through the foil removal hole. A through hole formed by the foil removal hole through which the stitch needle is inserted through the terminal and the cathode foil and a foil piece are formed in the cathode foil, and a foil piece is formed in the cathode foil from the terminal hole and the edge of the terminal hole. forming the lead-out terminal with a terminal piece extending through the through-hole; and pressing the terminal piece to connect the cathode foil and the lead-out terminal; The end has a base material exposed surface where the base material foil is exposed, and when the stitch needle is inserted through the drawer terminal and the cathode foil, the base material exposed surface is formed on the foil piece, and the base material exposed surface is formed on the foil piece. The foil piece moves to one side of the terminal, and the exposed surface of the base material intersects with the pressing direction of the terminal piece to connect with the terminal piece.

In the capacitor manufacturing method described above, the cross-sectional area of the perforation portion of the stitch needle may satisfy the following formula.
Cross-sectional area of perforation>S1-S2
S1: Opening area of the foil removal hole S2: Cross-sectional area of the pull-out terminal located inside the through-hole

According to the above aspects of the present disclosure, for example, any of the following effects can be obtained.

(1) The exposed surface of the base material at the tip of the foil piece extending from the edge of the through hole connects with the terminal piece, so the base foil and the terminal piece come into direct contact without the carbon layer, and the metal materials The contact ensures a stable physical and electrical connection.

(2) If there is an exposed surface of the base material at the tip of the foil piece, the relative movement between the terminal piece and the foil piece during pressing is suppressed due to direct contact between the base material foil and the terminal piece at the tip of the foil piece. , the dispersion of the pressing force is suppressed.

(3) A stitch connection suitable for the properties of the cathode foil can be realized.

(4) The stability or reliability of a capacitor equipped with a cathode foil containing a carbon layer can be improved.

It is a figure showing an example of the terminal connection part of the capacitor concerning an embodiment. 2 is a diagram showing a cross section taken along the line IIA-IIA in FIG. 1. FIG. It is a figure which shows an example of the end surface of a cathode foil. It is a figure which shows an example of the formation process of the foil removal hole in cathode foil. It is a figure which shows an example of the connection process of the extraction terminal to electrode foil. FIG. 3 is a diagram for explaining the arrangement of stitch needles and foil removal holes. It is a figure for explaining an example of stress and movement of a member at the time of pressing. FIG. 3 is a diagram illustrating an example of a comparison of contact resistances of capacitors according to an example and a comparative example. It is a figure which shows an example of the experimental result of a 5th sample from a 1st sample. It is a figure showing a sample. It is a figure which shows an example of the cross section of the terminal connection part of the capacitor|condenser based on a modification. FIG. 3 is a diagram for explaining connection of a lead terminal to a cathode foil.

FIG. 1 shows an example of a terminal connection portion of a capacitor according to an embodiment. FIG. 2 shows a cross section taken along line IIA-IIA in FIG. FIG. 3 shows an example of the end face of the cathode foil. The configurations shown in FIGS. 1 to 3 are examples, and the technology of the present disclosure is not limited to such configurations. The terminal connection portion includes the connection location where the lead terminal 4 is connected to the cathode foil 6 by stitch connection, that is, the stitch connection portion 10 and its surrounding portion. The stitch connection portion 10 is a region where the terminal piece 34 overlaps at least the flat portion 32 and the cathode foil 6, and is a shaded portion in A of FIG. The cross section shown in FIG. 2 is an example of a central cross section passing through the center of the terminal piece 34, and the center of the terminal piece 34 is connected to a line passing through the tip 40 of the terminal piece 34 and the center C of the base 38. Defined by FIG. 2B is an enlarged view of region IIB shown in FIG. 2A.

The capacitor 2 is an example of an electronic component, and is, for example, an electrolytic capacitor. The capacitor 2 includes, for example, a capacitor element, a lead 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 a portion of the lead-out terminal 4 are inserted into the exterior case, and a sealing member is installed in the opening of the exterior case. The drawer 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, anode foil and separator are stacked and wound to form a wound element such that the separator is placed between the cathode foil 6 and the anode foil. This 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 base foil 12 and a carbon layer 14. The base foil 12 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. As shown in FIG. 3, the surface of the base foil 12 has unevenness 16 formed by etching, for example, and the surface area of the base foil 12 is expanded. The surface of the base foil 12 may include, for example, tunnel-shaped or cavernous etching pits, and these tunnel-shaped or cavernous etching pits may form the unevenness 16.

The carbon layer 14 is arranged, for example, on both sides of the base foil 12. The carbon layer 14 may be arranged only on one surface of the base foil 12. As shown in FIG. 3, the carbon layer 14 partially penetrates into the concavo-convex portions 16, so that the carbon layer 14 closely adheres to and engages with the concavo-convex portions 16 of the base foil 12. That is, the carbon layer 14 has a surface shape that engages with the unevenness 16. The carbon layer 14 is arranged on the outside of the base foil 12, and the cathode foil 6 has a two-layer structure of the base foil 12 and the carbon layer 14, or a three-layer structure with the carbon layer 14 arranged on both sides of the base foil 12. ing. 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 nanohorn, amorphous carbon, natural graphite, artificial graphite, graphitized Ketjenblack, mesoporous carbon, and fibrous carbon. Activated carbon is produced, for example, from natural plant tissues such as coconut shells, synthetic resins such as phenol, and those derived from fossil fuels such as coal, coke, or pitch. Carbon blacks include Ketjen black, acetylene black, channel black or thermal black. Fibrous carbon includes carbon nanotubes, carbon nanofibers, and the like. The carbon nanotube may be a single-walled carbon nanotube with a single layer of graphene sheets, or a multi-walled carbon nanotube (MWCNT) with two or more layers of graphene sheets rolled coaxially to form a multilayered tube wall.

The carbon material is preferably carbon black, which is spherical carbon. By using spherical carbon black with an average primary particle size of 100 nanometers or less, the carbon layer 14 becomes dense. In addition, by using carbon black with a particle size smaller than the opening diameter of the unevenness 16 formed by etching on the surface of the cathode foil 6, the carbon black easily penetrates deep into the unevenness 16, and the carbon layer 14 is formed on the surface of the cathode foil 6. The carbon layer 14 is in close contact with the base foil 12, and the interfacial resistance between the carbon layer 14 and the base foil 12 tends to decrease. The carbon material is preferably a mixture containing spherical carbon and graphite. Graphite is, for example, natural graphite, artificial graphite, or graphitized Ketjenblack, and has a shape such as flaky, scale-like, lump-like, earth-like, spherical, or flake-like. The graphite is preferably in the form of scales or flakes, and the aspect ratio of the short axis to the long axis of the graphite is preferably in the range of 1:5 to 1:100. The scale-like or flaky graphite having the above-mentioned aspect ratio can push spherical carbon into the unevenness 16 such as an etching pit, so that a part of the carbon layer 14 can be formed even inside the etching pit. Therefore, the carbon layer 14 can firmly adhere to the base foil 12 due to the anchor effect.

When the carbon material is a mixture of graphite and spherical carbon, in order to obtain the effect of a combination of graphite and spherical carbon, the mass ratio of graphite to the mixture of graphite and spherical carbon [mass of graphite / (mass of graphite + mass of spherical carbon) mass)] is, for example, in the range of 25% or more and 90% or less.

The binder is a resin binder such as styrene-butadiene rubber, polyvinylidene fluoride, or polytetrafluoroethylene, and binds the carbon material. The dispersant is, for example, sodium carboxymethyl cellulose.

The cathode foil 6 has a through hole 18 and a foil piece 20. 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 over the cathode foil 6 itself to form a folded portion 24 on the outside of the edge 22. The foil piece 20 has a base material exposed surface 28 on which the base material foil 12 is exposed at the tip and the vicinity of the tip (hereinafter, the tip and the vicinity of the tip will be referred to as the "tip part"). The base material exposed surface 28 may extend to the edge 22 of the through hole 18 . The exposed surface 28 of the base material is not covered with the carbon layer 14, and bare metal (that is, the valve metal described above) is exposed. The base material exposed surface 28 intersects with the direction of penetration of the through hole 18, which is represented by the double-headed arrow shown in FIG. 2B. That is, the base material exposed surface 28 is not parallel to the penetration direction, but is inclined or perpendicular to the penetration direction. It is preferable that the angle θ between the penetrating direction of the through hole 18 and the exposed surface 28 of the base material is, for example, 45 degrees or more and 90 degrees or less. As the angle θ increases toward 90 degrees, the exposed base surface 28 and the portion of the terminal piece 34 that connects to the exposed base surface 28 are arranged to face each other, so that connectivity becomes more stable. Further, since the base material exposed surface 28 and the portion of the terminal piece 34 connected to the base material exposed surface 28 are arranged to face each other, the pressing force applied during stitch connection is efficiently transmitted to the connecting portion. Therefore, the pressing force applied to the base material exposed surface 28 increases, and the physical and electrical connection between the base material exposed surface 28 and the lead-out terminal 4 becomes stronger.

The pressing force at the time of stitch connection is, for example, parallel to the penetrating direction of the through hole 18, and the pressing direction of the terminal piece 34 and the foil piece 20 is parallel to the penetrating direction of the through hole 18. This pressing force can be decomposed into a first component force perpendicular to the exposed surface 28 of the base material and a second component force parallel to the exposed surface 28 of the base material using a vector. When the angle θ is 45 degrees, the first component force is one half of the root of the pressing force (that is, 1/√2), and the pressing force is reduced due to the slope of the base material exposed surface 28. can be suppressed to about 30%.

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 consists of, for example, tunnel-like pits formed by etching, cavernous pits, or voids between densely packed powders. 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-out terminal by a stitch connection or other connection means.

The separator is placed 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, including kraft as a separator member, and may also include other separator members such as Manila hemp, esparto, hemp, rayon, cellulose, and mixtures thereof.

The lead terminal 4 is made of a conductive metal such as aluminum. The lead terminal 4 is, for example, a lead terminal including a lead wire, a terminal portion, and a terminal piece 34. The terminal portion is made of an aluminum wire, and is made up of a substantially cylindrical round bar portion and a flat portion 32 formed by press working or the like on one end side of the aluminum wire. An inclined portion whose thickness decreases linearly to the thickness of the flat portion 32 is formed between the round bar portion and the flat portion 32. The lead wire is made of, for example, a metal wire, and is connected to the round bar portion by arc welding. The flat portion 32 overlaps the terminal mounting surface of the cathode foil 6 and includes a terminal hole 36 . The terminal hole 36 is arranged at a position overlapping the through hole 18. The terminal piece 34 is formed on the flat part 32, extends from the edge of the terminal hole 36 of the flat part 32, passes through the through hole 18, and is led out to the side opposite to the terminal mounting surface of the cathode foil 6. is pressed against the opposite side of the The lead terminal 4 is connected to the cathode foil 6 at the stitch connection portion 10 by sandwiching the cathode foil 6 between the flat portion 32 and the bent terminal piece 34. The terminal piece 34 covers the entire foil piece 20 in the central cross-section shown in FIG. 2, for example, and is connected to the base material exposed surface 28 facing the terminal piece 34. That is, the base material exposed surface 28 exists between the base 38 and the tip 40 of the terminal piece 34. The valve metal connection between the terminal piece 34 and the exposed base surface 28 suppresses slippage or relative movement of the cathode foil 6 and strengthens the physical and electrical connection.

The electrolyte is an electrolytic solution, a gel electrolyte, a solid electrolyte containing a conductive polymer, etc. A so-called hybrid electrolytic capacitor may be formed by including an electrolytic solution or gel electrolyte and a solid electrolyte containing a conductive polymer.

In the electrolytic solution of an electrolytic capacitor, a solute is dissolved in a solvent, and additives are added as necessary. The solvent may be either a protic polar solvent or an aprotic polar solvent. Examples of the protic polar solvent include monohydric alcohols, polyhydric alcohols, oxyalcohol compounds, and water. Examples of the aprotic polar solvent include sulfone type, amide type, lactone type, cyclic amide type, nitrile type, and oxide type. The solute contains anionic and cationic components, and is typically an organic acid or a salt thereof, an inorganic acid or a salt thereof, a complex compound of an organic acid and an inorganic acid, or an ionically dissociable salt thereof; or a combination of two or more. An acid serving as an anion and a base serving as a cation may be separately added to the electrolytic solution as solute components.

When using a solid electrolyte, for example, a conductive polymer is contained in the electrolyte layer. The conductive polymer is a conjugated polymer or a doped conjugated polymer. As the conjugated polymer, any known conjugated polymer can be used without particular limitation. Conjugated polymers include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, polythiophene vinylene, etc., with poly(3,4-ethylenedioxythiophene) being preferred. The conjugated polymer may be used alone, two or more types may be used in combination, or a copolymer of two or more types of monomers may be used.

FIG. 4 shows an example of the process of forming foil removal holes in the cathode foil in the capacitor manufacturing process. FIG. 5 shows an example of the step of connecting the lead terminal to the electrode foil in the capacitor manufacturing process. The configurations shown in FIGS. 4 and 5 are examples, and the technology of the present disclosure is not limited to the configurations shown in FIGS. 4 and 5.

The manufacturing process of the capacitor 2 is an example of the capacitor manufacturing method of the present disclosure, and includes, for example, an anode foil manufacturing process, a cathode foil 6 manufacturing process, a separator manufacturing process, a lead terminal 4 manufacturing process, and an electrode foil manufacturing process. The process includes a process of connecting the lead terminal 4, a process of manufacturing the capacitor element, and a process of encapsulating the capacitor element.

In the anode foil manufacturing process, for example, 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 applied to the surface of the valve metal foil with the enlarged surface portion formed thereon by chemical conversion treatment. form. The enlarged surface portion is formed by direct current etching, alternating current etching, or vapor deposition or sintering of metal particles on the valve metal foil. In direct current or alternating current etching, a direct or alternating current is typically applied to a valve metal foil immersed in an acidic aqueous solution containing halogen ions, such as hydrochloric acid. An anode foil is produced by cutting the valve metal foil on which the dielectric oxide film is formed.

In the step of producing the cathode foil 6, the base foil 12 is produced by, for example, forming the unevenness 16 on the surface of the valve metal foil described above by etching. The etching of the cathode foil 6 may be the same as or different from the etching of the anode foil. A carbon layer 14 is formed on the base foil 12, and the cathode foil 6 is produced. The thickness of the carbon layer 14 is adjusted to, for example, 1 to 2 μm.

The carbon layer 14 is formed, for example, as follows. The above-mentioned carbon material, binder, and dispersant are added to the diluted liquid and mixed by a dispersion process such as a mixer, jet mixing, ultracentrifugation, and ultrasonication to form a slurry. Examples of the diluent include alcohol, hydrocarbon solvents, aromatic solvents, amide solvents, water, and mixtures thereof. 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, push the carbon material into the pores of the unevenness 16 and deform the carbon material along the uneven surface of the unevenness 16, thereby improving, for example, the adhesion between the carbon layer 14 and the base foil 12. Improves fixing properties. When the carbon material contains graphite, the press aligns the graphite and deforms the graphite along the unevenness 16 of the base foil 12. When the graphite is pressed against the unevenness 16, the press forces the spherical carbon into the unevenness 16, brings the slurry into close contact with the base foil 12, and as a result, brings the carbon layer 14 into close contact with the base foil 12. When the carbon material is only spherical carbon, for example, spherical carbon having an average primary particle diameter of 100 nanometers or less enters the unevenness 16, and the interfacial resistance between the carbon layer 14 and the base foil 12 can be reduced. In addition, when the carbon material is only spherical carbon, the coefficient of static friction on the surface of the carbon layer 14 is improved, and when the terminal piece 34 is pressed against the cathode foil 6, it becomes difficult to slip, and a stitch connection with stable connectivity can be obtained. .

The cathode foil 6 with the carbon layer 14 formed on the base foil 12 is cut into strips. Next, a foil removal hole 52 (C in FIG. 4) is formed in the cathode foil 6 cut into strips. The foil removal hole 52 is formed, for example, as follows. As shown in FIG. 4A, the base foil 12 with the carbon layer 14 is placed on the mounting surface of a punching table 56 having punched holes 54. As shown in FIG. As shown in FIGS. 4A to 4C, a hole punching means 58 having a slightly smaller cross section than the punch hole 54 is inserted into the punch hole 54 from the mounting surface side, and the carbon layer 14 on the punch hole 54 and The base foil 12 is cut off by cutting such as shearing or breaking, and a foil removal hole 52 is formed in the base foil 12 together with the carbon layer 14 . At the cut surface 60 of the foil removal hole 52, the base foil 12 is not covered with the carbon layer 14 and is exposed. The cut surface 60 is an example of the edge of the foil removal hole 52, and forms the base material exposed surface 28 in the capacitor 2.

The foil removal hole 52 has the same or approximately the same size and shape as the cross section of the hole punching means 58. That is, the size and shape of the foil removal hole 52 can be adjusted by adjusting the cross section of the punching means 58 and the size or shape of the punch hole 54. As shown in FIG. 6, the foil removal hole 52 is, for example, a square or a substantially square whose length on one side is L1.

In the separator production process, the separator member described above is cut to produce a separator.

In the manufacturing process of the lead-out terminal 4, the flat portion 32 is formed by, for example, pressing one end side of the substantially cylindrical round rod portion made of the conductive metal described above. The side of the round bar portion where the flat portion 32 is not formed is connected to the lead wire by arc welding or the like to produce the lead terminal 4 before stitch connection.

In the step of connecting the lead terminal 4 to the electrode foil, the lead terminal 4 is connected to the cathode foil 6 and the anode foil, respectively.

As shown in FIG. Specifically, the flat portion 32) is superimposed on the upper surface of the cathode foil 6, that is, the terminal arrangement surface. A second mold 64 such as an upper mold is installed on the top surface of the lead-out terminal 4. Therefore, the cathode foil 6 and the lead-out terminal 4 are sandwiched between the first mold 62 and the second mold 64 and held by the first mold 62 and the second mold 64.

The first mold 62 has a through hole 66 and the second mold 64 has a through hole 68. The through hole 68 is smaller than the through hole 66 and is arranged directly above the through hole 66. Stitch needle 70 is positioned above through-hole 68 , and foil removal hole 52 of cathode foil 6 is positioned directly below through-hole 68 and stitch needle 70 .

The stitch needle 70 has, for example, a cylindrical shaft portion and an acute-angled, quadrangular pyramid-shaped tip portion, and the projection view 74 of the perforation portion 72 (B in FIG. 5) of the stitch needle 70 onto the cathode foil 6 (FIG. 6) is, for example, a square or a substantially square whose length on one side is L2. The perforation part 72 is a part of the tip of the stitch needle 70, and is a contact part of the pull-out terminal of the stitch needle 70 inserted to the set position. When the perforation portion 72 reaches the pull-out terminal 4, the stitch needle 70 stops and the expansion of the through hole 18 and the terminal hole 36 basically stops. As shown in FIG. 6, the position of the stitch needle 70 in the rotational direction is adjusted so that the projected view 74 is rotated, for example, by 45 degrees with respect to the foil removal hole 52. When the projected view 74 is rotated, for example, by 45 degrees with respect to the foil removal hole 52, the cathode foil 6 is not present in the area of the center C shown in FIG. exists. Therefore, the stress applied to the foil pieces 20 existing in the area of the center C is smaller than that of the foil pieces 20 existing in the areas sandwiching the center C when the stitch needle 70 is inserted through the cathode foil 6. Since there is less stress when the stitch needle 70 is inserted, the base material exposed surface 28 in the region of the center C is formed more stably than the base material exposed surface 28 in the region sandwiching the center C, and the stitch connection is made easier. This is suitable for checking the connection status. The rotation of the projection 74 with respect to the foil removal hole 52 is not limited to 45 degrees. For example, any angle may be used as long as the same or similar structure as the capacitor 2 can be obtained.

The stitch needle 70, which has the above-described structure and whose position in the rotational direction has been adjusted, is lowered in the direction of the block arrow shown in FIG. 5A, and as shown in FIG. It is inserted into the foil removal hole 52 of the drawer terminal 4 and the cathode foil 6 from the drawer terminal 4 side. By inserting the stitch needle 70, a through hole 18 and a foil piece 20 are formed in the cathode foil 6, and a terminal hole 36 and a terminal piece 34 are formed in the lead-out terminal 4. The cut surface 60 of the foil removal hole 52 will be placed on the formed foil piece 20, and both the foil piece 20 and the terminal piece 34 will move in the insertion direction of the stitch needle 70 (that is, downward). become. In other words, the cut surface 60 moves toward the terminal piece 34 together with the foil piece 20. The lowered stitch needle 70 is raised and removed from the pull-out terminal 4 and the cathode foil 6.

When the stitch needle 70 stops, the perforation part 72 of the stitch needle 70 comes into contact with the surface of the terminal hole 36 formed in the pull-out terminal 4, as shown in FIG. 5B. The perforation 72 is a part of an acute-angled, quadrangular pyramid-shaped tip. Therefore, in the terminal hole 36, the opening distance changes in the direction of penetration of the terminal hole 36 or the direction of insertion of the stitch needle 70. For example, the opening distance on the lower surface of the lead-out terminal 4 (the surface in contact with the cathode foil 6) is smaller than the opening distance in the upper surface of the lead-out terminal 4 (the surface opposite to the surface in contact with the cathode foil 6). That is, the opening area of the terminal hole 36 gradually increases from the bottom surface to the top surface of the drawer terminal 4, and the side surface of the terminal hole 36 has a wide angle from the bottom surface to the top surface of the drawer terminal 4.

The mold 76 has, for example, a flat pressing surface on the upper side and is arranged below the through hole 66. The mold 76 is raised in the direction of the block arrow shown in FIG. As shown in FIG. 5C, the terminal piece 34 and the foil piece 20 are sandwiched between the second mold 64 and the mold 76. The terminal piece 34 and the foil piece 20 are folded back by pressing, and the lead-out terminal 4 is connected to the cathode foil 6. Moreover, the cut surface 60 of the foil removal hole 52 is stretched by pressing, and the base material exposed surface 28 having an exposed length larger than the thickness T1 of the cathode foil 6 is formed.

The cross-sectional area of the perforation 72, that is, the area of the projected view 74, is adjusted, for example, to satisfy the following formula (1). By transforming equation (1), the following equation (2) is obtained. Instead of the cross-sectional area of the perforation part 72, the opening area of the foil removal hole 52 may be adjusted.
Cross-sectional area of perforation 72 + S2 > S1 ... (1)
Cross-sectional area of perforation 72>S1-S2...(2)
S1: Opening area of foil removal hole 52 S2: Cross-sectional area of pull-out terminal 4 located inside through-hole 18

S2 is, for example, the annular area of the lead-out terminal 4 located on the broken line BL shown in FIG. This is the cross-sectional area of the pull-out terminal 4 between the perforations 72. When the total area of the cross-sectional area of the perforation part 72 and S2 is larger than S1, the foil removal hole 52 tends to expand, and the cut surface 60 of the foil removal hole 52 tends to move in the insertion direction of the stitch needle 70. In other words, it becomes easier to obtain the base material exposed surface 28 facing the terminal piece 34.

The length L2 of one piece of the projection view 74 (that is, the length of one piece of the perforation part 72) may be adjusted using the following formula (3) instead of formulas (1) and (2).
L2+2×T2>L1...(3)
T2: Thickness of the pull-out terminal 4 located inside the through hole 18 (for example, the length of the broken line BL shown in A of FIG. 2)

The cross-sectional area of the perforation part 72 or the opening area S1 of the foil removal hole 52 is adjusted so as to satisfy the following formula (4) or formula (5), or the length L2 of one piece of the perforation part 72 or the opening area S1 of the foil removal hole 52 is adjusted to satisfy the following formula (4) or formula (5). When the length L1 of one side is adjusted to satisfy the following formula (6) or formula (7), it becomes easier to obtain the base material exposed surface 28 facing the terminal piece 34.
Cross-sectional area of perforation 72≧S1...(4)
Cross-sectional area of perforation 72>S1...(5)
L2≧L1...(6)
L2>L1...(7)

As the cross-sectional area of the perforation 72 becomes larger, the base material exposed surface 28 becomes farther away from the through-hole 18. Therefore, the upper limit of the cross-sectional area of the perforation 72, the lower limit of the opening area S1, and the upper limit of the length L2 are set so that the base material exposed surface 28 is arranged closer to the through hole 18 than the tip 40 of the terminal piece 34. Alternatively, a lower limit value of the length L1 may be set.

When the pressing surface of the mold 76 presses the lead terminal 4 and the cathode foil 6 in the direction of the block arrow D1 shown in FIG. 7B, stress P acts in the pressing direction or substantially in the pressing direction. As shown in FIG. 7A, the opening area of the terminal hole 36 gradually increases from the bottom surface to the top surface of the pull-out terminal 4. Therefore, the hole-nearby portion of the pull-out terminal 4 disposed around the terminal hole 36 can move to the space 78 near the side surface of the terminal hole 36 on the upper surface side of the pull-out terminal 4. Therefore, the stress acting in the direction perpendicular to or intersecting the pressing direction (for example, along the lower surface of the pull-out terminal 4) is reduced, and the terminal piece 34 is moved in the direction of the dashed arrow D2 shown in FIG. , along the surface of the cathode foil 6).

If the area of the opening of the terminal hole 36 is approximately the same between the bottom surface and the top surface of the pull-out terminal 4, it is assumed that the portion of the pull-out terminal 4 near the hole occupies the space 78 before being pressed. It is assumed that when the stress P acts in the pressing direction or substantially in the pressing direction, the portion of the pull-out terminal 4 near the hole cannot move into the space 78. Therefore, stress is expected to act in a direction perpendicular to or crossing the pressing direction, and the terminal piece 34 may be more likely to move in the direction of the dashed arrow D2 than in the state shown in B of FIG. is assumed.

The process of connecting the lead terminal 4 to the anode foil may be the same as or different from the process of connecting the lead terminal 4 to the cathode foil 6.

In the manufacturing process of the capacitor element, the first separator is placed between the anode foil and the cathode foil 6, and the second separator is placed outside the anode foil or the cathode foil 6. A capacitor element is produced by winding the anode foil, the cathode foil 6, and the first and second separators.

In the capacitor element encapsulation process, a capacitor element impregnated with an electrolyte such as an electrolytic solution is inserted into the exterior case, and then a sealing member is attached to the opening of the exterior case to produce the capacitor 2.

According to the embodiment, for example, the following effects can be obtained.

(1) Since the base material exposed surface 28 is connected to the terminal piece 34, the base material foil 12 and the terminal piece 34 are in direct contact without intervening the carbon layer 14, and physical and electrical The connection becomes stable.

(2) Direct contact between the base foil 12 and the terminal piece 34 at the tip of the foil piece 20 suppresses the relative movement between the terminal piece 34 and the foil piece 20 during pressing, and suppresses the dispersion of the pressing force. .

(3) By forming the foil removal hole 52 in advance in the cathode foil 6, the size of the foil piece 20 is suppressed. Therefore, the elongation of the cathode foil 6, especially the foil piece 20, during pressing is suppressed, and the dispersion of the pressing force is suppressed. Further, the protrusion or exposure of the foil piece 20 from the terminal piece 34 is suppressed. The foil piece 20 protruding from the terminal piece 34 does not contribute to electrical connectivity or connection strength. On the other hand, when the foil piece 20 pops out from the terminal piece 34, the exposed base surface 28 at the tip of the foil piece 20 has a structure that does not come into contact with the terminal piece 34. Therefore, there is no effect of suppressing relative movement due to contact between metals, and the foil piece 20 easily moves from the root portion toward the tip of the foil piece 20, and the connection between the cathode foil 6 and the lead-out terminal 4 is achieved by dispersing the pressing force. There are concerns about a decline in sexuality. By suppressing the protrusion or exposure of the foil piece 20, the dispersion of the pressing force is suppressed, and the connectivity between the cathode foil 6 and the lead-out terminal 4 is stabilized.

(4) Since the base material exposed surface 28 intersects with the penetration direction of the through hole 18, the pressing force applied during stitch connection acts as a force that presses the terminal piece 34 against the base material exposed surface 28. Acts on exposed surface 28. Therefore, compared to the case where the base material exposed surface 28 is parallel to the penetration direction, the physical and electrical connection between the terminal piece 34 and the foil piece 20 can be strengthened. Furthermore, since the pressing force applied during stitch connection stretches the base material exposed surface 28, the contact area between the metal materials can be increased compared to when the base material exposed surface 28 is parallel to the penetration direction. .

(5) 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 provided with the cathode foil 6 including the carbon layer 14 can be improved.

(6) The stitch needle 70 forms a terminal hole 36 whose opening area gradually increases from the bottom surface to the top surface of the pull-out terminal 4. Therefore, when the mold 76 presses the pull-out terminal 4 and the cathode foil 6, the area near the hole of the pull-out terminal 4 can move into the space 78, and the terminal piece 34 is moved in the direction along the surface of the cathode foil 6. Movement is suppressed.

The capacitor 2 according to the embodiment is a capacitor 2 according to an embodiment in which the length L1 of one side of the foil removal hole 52 and the length L2 of one side of the perforation part 72 are adjusted to the values shown below. Note that the thickness of the flat portion 32 is 0.23 mm, and the thickness T1 of the cathode foil 6 is 20 μm.
・L1: 0.50mm
・L2: 0.51mm

The capacitor according to the comparative example is a capacitor manufactured in the same manufacturing process as the capacitor 2 according to the example, except that the foil removal hole 52 was not formed. Since the foil removal hole 52 was not formed, the capacitor according to the comparative example has a larger foil piece than the foil piece 20 of the capacitor 2 according to the example, and does not include the base material exposed surface 28 due to the cut surface 60. .

The contact resistance of the capacitor 2 according to the example is compared with the contact resistance of the capacitor according to the comparative example. As shown in A of FIG. 8, in the capacitor 2 according to the example, the average value (Ave), maximum value (Max), and minimum value (Min) of the contact resistance (unit: mΩ) of the five capacitors 2 are as follows. They were 0.78, 0.82, and 0.74. In the capacitor according to the comparative example, the average value, maximum value, and minimum value of the contact resistance (unit: mΩ) of the five capacitors were 0.80, 0.94, and 0.74, respectively.

FIG. 8B shows the measurement results of contact resistance in a graph. In the graph shown in FIG. 8B, the average value is represented by a black square, and the maximum and minimum values are represented by white circles. The bidirectional arrow in the graph shown in FIG. 8B represents the width of the variation. In the capacitor 2 according to the example, a decrease in the average value of contact resistance was observed and a decrease in the width of variation was observed as compared to the capacitor according to the comparative example. It has been found that by providing the foil removal hole 52 in the cathode foil 6 in advance, the stability of the connection of the capacitor 2 is improved.

FIG. 9 shows an example of experimental results for the first to fifth samples. Figure 10 shows the sample.

The first to fifth samples include a cathode foil 84 and a lead terminal 86, as shown in FIG. The lead-out terminal 86 is a terminal similar to the lead-out terminal 4 already described in the embodiment, and is connected to the cathode foil 84 by stitch connection at three connecting portions 88-1, 88-2, and 88-3. The distance between the centers of adjacent connecting portions 88-1, 88-2, and 88-3 is 3.0 mm. The connecting portion 88-1 is closer to the side edge 90 of the cathode foil 84 than the connecting portions 88-2 and 88-3, and the distance between the center of the connecting portion 88-1 and the side edge 90 is 2.5 mm. Note that the first to fifth samples include a cathode foil 84 and a lead terminal 86 for a capacitor, which are larger in product size than those of the example and comparative example, and the size of the lead terminal 86 is larger than that of the example and comparative example. It is different from the pull-out terminal 4. In the first to fifth samples, the thickness of the flat portion is 0.29 mm.

The cathode foils 84 of the first to fourth samples include the base foil 12 already described in the embodiment and a layer formed on one side of the base foil 12. In the first to fourth samples, the layers formed on the base foil 12 are a carbon layer 14, a titanium carbide layer (thickness: 0.1 to 0.12 μm), and a titanium nitride layer (thickness: It is a double layer of titanium and carbon (thickness: approximately 0.08 μm). The cathode foil 84 of the fifth sample was made only of aluminum foil. The carbon layer 14 is the carbon layer 14 described in the embodiment. The titanium carbide layer, the titanium nitride layer, and the titanium/carbon double layer are formed by vapor deposition such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). The titanium and carbon double layer has a base layer of titanium layer and a top layer of carbon layer.

The cathode foil 84 of the first sample was manufactured by mixing carbon and a resin binder to create a slurry, applying the created slurry to an etched aluminum foil, and pressing it. The cathode foil 84 of the second sample was produced by forming a titanium carbide layer on an etched aluminum foil by arc ion plating. The cathode foil 84 of the third sample was fabricated by forming a titanium nitride layer on an etched aluminum foil by arc ion plating. The cathode foil 84 of the fourth sample was produced by forming a titanium layer on an etched aluminum foil by sputtering, and then forming a carbon layer on the formed titanium layer by sputtering.

The stitch needle used in stitch connection has a square pyramid-shaped tip, the length of one side of the square pyramid is 0.8 mm, and the angle of the tip is 20 degrees. The first to fifth samples (with foil removal holes) are produced by stitch-connecting a lead terminal 86 to a cathode foil 84 having a 0.9 mm square foil removal hole 52. The first to fifth samples (without foil removal holes) are produced by stitch-connecting the lead terminal 86 to the cathode foil 84 in which the foil removal hole 52 is not formed.

A resistance meter (manufactured by Hioki Electric Co., Ltd., model number: RM3545) was brought into contact with the round bar part of the pull-out terminal 86 and the cathode foil 84, and the resistance was measured at no load, at 0.5 tension, and at 1.0 tension. . The measured resistance is the resistance (contact resistance) between the contact points that the probe of the ohmmeter contacts, and includes the resistance of the cathode foil 84, the resistance of the lead terminal 86, and the connection resistance of the lead terminal 86 to the cathode foil 84. including. 0.5 tension means pulling the end of the round bar portion of the pull-out terminal 86 by about 0.5 mm in parallel to the perpendicular line to the cathode foil 84 so that tension acts between the pull-out terminal 86 and the cathode foil 84. . 1.0 tension means that the end of the round bar portion of the pull-out terminal 86 is pulled by approximately 1.0 mm in parallel to the perpendicular line to the cathode foil 84 so that tension is applied between the pull-out terminal 86 and the cathode foil 84. . No load indicates that the end of the round bar portion of the extraction terminal 86 is not pulled.

From the experimental results shown in FIG. 9, it was confirmed that in the first sample, there was a clear difference in resistance value depending on whether or not the foil removal hole 52 was formed. On the other hand, in the second to fifth samples, the difference in resistance value depending on whether or not the foil removal hole 52 was formed was not clear. It was confirmed that the effect of forming the foil removal holes 52 was particularly noticeable in the carbon layer 14 containing the binder. In the carbon layer 14 containing a binder, the pressing force is easily dispersed in the plane direction. Therefore, the carbon layer 14 is considered to have a large influence on connectivity, and it is considered that the effect obtained by forming the foil removal holes 52 is high.

Features and modifications of the embodiments and examples are listed below.

(1) The capacitor element, the lead-out terminal 4, the outer case, the sealing member, the electrolyte, etc. are not limited to those described in the embodiment. These materials may be other materials employed in aluminum electrolytic capacitors or similar capacitors. For example, the pull-out terminal 4 may be a tab terminal, and the sealing member may be a phenol laminate to which an external terminal is attached. After the capacitor element is impregnated with electrolyte, the lead-out terminal 4 led out from the capacitor element may be connected to the external terminal of the sealing member, and the capacitor element and the sealing member are inserted into the outer case and sealed with the sealing member. It is also possible to have a similar structure. The capacitor element may be a laminated element in which a plurality of flat anode foils, cathode foils 6, and separators are laminated, for example. The material of the carbon layer 14 is not limited to that described in the embodiment. The material forming the carbon layer 14 may be any conductive material containing carbon. Furthermore, the state of contact or engagement of the carbon layer 14 with the base foil 12 is not limited to that described in the embodiment.

(2) In the embodiments and examples, the lead terminal 4 is placed on the cathode foil 6, the stitch needle 70 pierces the lead terminal 4 and the cathode foil 6 from above, and the mold 76 is inserted into the lead terminal 4 and the cathode foil 6 from below. The cathode foil 6 is pressed. The lead terminal 4, the cathode foil 6, the stitch needle 70, and the mold 76 may be arranged upside down or rotated by an arbitrary angle relative to the arrangement described in the embodiment, for example.

(3) In the embodiments and examples, with both the cathode foil 6 and the lead-out terminal 4 held between the first mold 62 and the second mold 64, the stitch needle 70 is pulled out between the lead-out terminal 4 and the cathode foil. 6 and press the terminal piece 34 and the foil piece 20 to form the stitch connection part 10, but the invention is not limited thereto. For example, with both the cathode foil 6 and the drawer terminal 4 held between the first die 62 and the second die 64, the stitch needle 70 is inserted through the drawer terminal 4 and the cathode foil 6, and then the first The holding by the mold 62 and the second mold 64 is released, and with at least the terminal piece 34 formed, the cathode foil 6 and the lead-out terminal 4 are sent to the next process, and at least the surface side on which the terminal piece 34 is formed is separated. Alternatively, the stitch connection portion 10 may be formed by pressing from the pullout terminal 4 side with a mold having a flat pressing surface.

(4) In the embodiments and examples, after the foil removal hole 52 is formed using the punching table 56 having the punched hole 54, the foil removal hole 52 formed in the cathode foil 6 and the through hole of the first mold 62 are The cathode foil 6 was placed on the first mold 62 so that the two molds 66 were aligned, and the cathode foil 6 and the lead-out terminal 4 were both sandwiched and held between the first mold 62 and the second mold 64 and connected. However, it is not limited to this. For example, the foil removal hole 52 is formed using the through hole 66 of the first mold 62 without using the drilling table 56, and this state is maintained to perform the process of connecting the lead terminal 4 to the cathode foil 6. You may go.

(5) In the embodiments and examples, the stitching is performed so that the projection 74 of the perforation part 72 (B in FIG. 5) of the stitch needle 70 onto the cathode foil 6 is rotated by 45 degrees with respect to the foil removal hole 52. Although the position of the needle 70 in the rotational direction is adjusted, the present invention is not limited thereto. For example, the rotation may be adjusted to be less than 45 degrees or more than 45 degrees. In addition, when the foil removal hole 52 and the projection 74 of the perforation part 72 of the stitch needle 70 onto the cathode foil 6 are at the same angle, that is, when the projection 74 coincides with the foil removal hole 52, or when the projection 74 is It may be adjusted so that it is one size larger or smaller than the removal hole 52.

(6) In the embodiments and examples, the cathode foil 6 includes the foil piece 20. However, the cathode foil 6 may not include the foil piece 20 and the base material exposed surface 28 may be formed on the upper surface of the edge 22 of the through hole 18 shown in FIG. 2B. In the process of connecting the lead terminal 4 to the cathode foil 6, the cut surface 60 of the foil removal hole 52 may move slightly due to the insertion of the stitch needle 70, and this slightly moved cut surface 60 is pressed. A base material exposed surface 28 may be formed at the edge 22 of the through hole 18 . If the base material exposed surface 28 exists at the edge 22 of the through hole 18 without the foil piece 20, the base material foil 12 and the terminal piece 34 will come into direct contact with each other at the edge 22 of the through hole 18, and the terminal piece 34 will not touch the terminal piece 34 when pressed. Relative movement between the cathode foils 6 is suppressed, and dispersion of the pressing force is suppressed.

(7) The shape of the foil removal hole 52 is not limited to a square or a substantially square. The shape of the tip of the stitch needle 70 is not limited to the quadrangular pyramid shape. It may be a rectangle or a regular polygon other than a square.

(8) The carbon layer 14 may be formed on the base foil 12 in which the foil removal holes 52 are formed. Since the surface unevenness of the cut surface 60 is small, the base material foil 12 on the cut surface 60 can be stretched by pressing, and can be exposed from the carbon layer 14 to form the base material exposed surface 28.

(9) As shown in FIG. 11, the extraction terminal 4 may have a metal surface portion 92 and a hardened surface portion 94. The metal surface portion 92 mainly contains the non-oxidized conductive metal contained in the lead-out terminal 4 and may contain a small amount of oxide of the conductive metal contained in the lead-out terminal 4. The hardened surface portion 94 is, for example, an oxidized surface portion containing an oxide of the conductive metal contained in the lead-out terminal 4, and is harder than the metal surface portion 92. In a terminal connection, such as a stitch connection 10, the metal surface 92 contacts the base foil 12, for example in a first region 96. The hardened surface portion 94 comes into contact with the carbon layer 14, for example in the second region 98, and the hardened surface portion 94 and the carbon layer 14 are laminated. The terminal connection portion may be a portion where the base material exposed surface 28 is placed, or may be a portion different from the portion where the base material exposed surface 28 is placed.

The first region 96 and the second region 98 are formed, for example, by the steps shown below.

As shown in FIG. 12A, before pressing, the pull-out terminal 4 (for example, the terminal piece 34) has, for example, a metal surface portion 92 and a hardened surface portion 94 on the surface, and the cathode foil 6 (for example, a foil Piece 20) has a carbon layer 14 covering base foil 12. The lead terminal 4 may have only a hardened surface portion 94 on its surface, and the cathode foil 6 may partially have a carbon layer 14 on its surface.

When the lead terminal 4 is pressed against the cathode foil 6 in the direction of the block arrow in FIG. 12B, the pressing force generates tension in the lead terminal 4 and the cathode foil 6 in the direction of the broken line arrow. The hard hardened surface portion 94 digs into the carbon layer 14, for example, to form a second region 98 as shown in FIG. In the second region 98, slippage or relative movement between the extraction terminal 4 and the cathode foil 6 is suppressed, for example, by a spike effect. The tension stretches or expands the lead terminal 4 and the cathode foil 6 along the contact surface of the lead terminal 4 and the cathode foil 6. In the lead-out terminal 4, for example, a metal surface portion 92 having higher deformability than the hardened surface portion 94 extends or expands, and in the cathode foil 6, for example, a portion in contact with the metal surface portion 92 expands or expands. or elongate or elongate in response to elongation. The elongation or expansion of the cathode foil 6 causes, for example, the carbon layer 14 to tear and separate, and the base foil 12 is exposed between the torn carbon layers 14 . A first region 96 is formed by contacting the exposed base foil 12 with the metal surface portion 92 .

The hardened surface portion 94 and carbon layer 14 that overlap each other may be torn and separated. In this case, the number of second regions 98 in which the hardened surface portion 94 overlaps the carbon layer 14 increases, and first regions 96 are formed between the second regions 98 .

In the process of connecting the lead terminal 4 to the cathode foil 6, the metal surface portion 92 may come into contact with the carbon layer 14 to form the third region 100, and the hardened surface portion 94 may come into contact with the base foil 12. , a fourth region 102 may be formed.

When the lead terminal 4 has the metal surface portion 92 and the hardened surface portion 94 and the first region 96 and the second region 98 are formed, the following effects can be obtained, for example.

(a) The metal surface portion 92 of the lead-out terminal 4 contacts the base foil 12 of the cathode foil 6. Therefore, the connection of the lead terminal 4 to the cathode foil 6 is physically and electrically stable due to the contact between the metal materials.

(b) The hardened surface portion 94 bites into the carbon layer 14 in the second region 98, and the sliding or relative movement of the cathode foil 6 with respect to the lead-out terminal 4 is suppressed. A reduction in the pressing force is suppressed, and the ease of connection between the lead terminal 4 and the cathode foil 6 can be improved.

(c) When the pull-out terminal 4 is connected, the metal surface portion 92 expands or expands. Since the sliding or relative movement of the cathode foil 6 is suppressed by the hardened surface portion 94, the portion of the cathode foil 6 that is in contact with the metal surface portion 92 stretches or expands to expose the base foil 12, and the metal surface The portion 92 can be brought into contact with the base foil 12.

(d) At the stitch connection portion 10, the foil piece 20 is folded over the cathode foil 6. In other words, the carbon layers 14 overlap each other, and the cathode foil 6 becomes slippery. Furthermore, since the carbon is pressed during the formation process of the carbon layer 14, the surface roughness of the carbon layer 14 becomes small, and the cathode foil 6 becomes easy to slip. The biting of the hardened surface portion 94 can effectively work against such slippery cathode foil 6.

As explained above, the most preferred embodiment of the present disclosure has been described, but the present disclosure is not limited to the above description, and the present disclosure is not limited to the invention described in the claims or disclosed in the specification. It goes without saying that those skilled in the art can make various modifications and changes based on the gist, and it goes without saying that such modifications and changes are included within the scope of the present disclosure.

The technology of the present disclosure is useful because it can be used for connecting a cathode foil containing a carbon layer and an extraction terminal, and for a capacitor containing these.

2

Capacitor

4, 86

Output terminal

6, 84 Cathode foil 10 Stitch connection part 12 Base material foil 14 Carbon layer 16 Unevenness 18 Through hole 20 Foil piece 22 Edge 24 Folded part 28 Base material exposed surface 32 Flat part 34 Terminal piece 36 Terminal hole 38 Root 40 Tip 52 Foil removal hole 54 Punch hole 56 Drilling stand 58 Drilling means 60 Cutting surface 70 Stitch needle 72 Perforation part 74 Projection view 76 Molding mold 78 Space part 88-1, 88-2, 88-3 Connection part 90 side edge 92 metal surface portion 94 hardened surface portion 96 first region 98 second region 100 third region 102 fourth region

Claims

A cathode foil including a base foil and a carbon layer formed on the base foil, and having a through hole;
a flat portion placed on the terminal placement surface of the cathode foil; and a flat portion formed on the flat portion that is led out through the through hole to the side opposite to the terminal placement surface of the cathode foil and bent. and a lead-out terminal connected to the cathode foil by sandwiching the cathode foil between the flat part and the terminal piece,
The cathode foil has a base material exposed surface where the base material foil is exposed at the tip of the foil piece extending from the edge of the through hole, and the base material exposed surface is connected to the base of the terminal piece. A capacitor, wherein the capacitor is disposed between tips of the capacitor, and the exposed surface of the base material is connected to the terminal piece.
The capacitor according to claim 1, wherein the exposed surface of the base material intersects with the penetration direction of the through hole.
3. The capacitor according to claim 2, wherein in a central cross section passing through a central portion of the terminal piece, an angle between the penetrating direction of the through hole and the exposed surface of the base material is 45 degrees or more and 90 degrees or less. .
2. The capacitor according to claim 1, wherein the exposed surface of the base material has an exposed length greater than the thickness of the cathode foil in a central cross section passing through the central portion of the terminal piece.
the lead-out terminal is connected to the cathode foil at a stitch connection;
The pull-out terminal has a metal surface portion and a hardened surface portion that is harder than the metal surface portion,
the metal surface contacts the base foil in a first region of the stitch connection;
2. The capacitor of claim 1, wherein the hardened surface is laminated to the carbon layer in a second region of the stitch connection.
A step of producing or preparing a cathode foil that includes a base foil and a carbon layer formed on the base foil and has a foil removal hole;
arranging a flat part of a lead terminal on the cathode foil so as to cover the foil removal hole;
The stitch needle is inserted through the drawer terminal and the cathode foil from the drawer terminal side so that the stitch needle is inserted through the foil removal hole, thereby forming a penetration formed by the foil removal hole into which the stitch needle is inserted. forming a hole and a foil piece in the cathode foil, and forming a terminal hole and a terminal piece extending from the edge of the terminal hole through the through hole in the lead-out terminal;
pressing the terminal piece to connect the cathode foil and the pull-out terminal,
The edge of the foil removal hole has a base material exposed surface where the base material foil is exposed,
When the stitch needle is inserted through the lead-out terminal and the cathode foil, the exposed surface of the base material is formed on the foil piece, and the foil piece moves to one side of the terminal,
A method for manufacturing a capacitor, characterized in that the exposed surface of the base material intersects with the pressing direction of the terminal piece and is connected to the terminal piece.
The cross-sectional area of the perforation of the stitch needle satisfies the following formula: Cross-sectional area of perforation>S1-S2
7. The method for manufacturing a capacitor according to claim 6, wherein S1: opening area of the foil removal hole; S2: cross-sectional area of a lead-out terminal located inside the through-hole.