JP2006332632A - Solid-state electrolytic capacitor and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stacked solid-state electrolytic capacitor which can reduce variation in element shape without increasing short circuit defects and stably manufacture a thin capacitor element, enables high capacity by increasing the number of stacking of capacitor elements in a solid-state electrolytic capacitor chip, and has small variation in equivalent series resistance, and to provide a manufacturing method thereof. <P>SOLUTION: An anode substrate for a solid state electrolytic capacitor, which is an anode substrate obtained by obliquely cutting a metal substrate including a valve metal layer having pores and a valve metal layer not having pores, is characterized in that it has a cut surface formed by extending the valve metal layer not having pores so as to follow a cutting edge; and the anode substrate for a solid state electrolytic capacitor is especially characterized in that a valve metal extending layer generated by extending the valve metal layer not having pores so as to follow the cutting edge in obliquely cutting the metal substrate and covering the end face of the valve metal layer having pores satisfies a specific condition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid electrolytic capacitor using a conductive polymer as a solid electrolyte layer and a method for producing the same.

  As shown in FIG. 2, the basic element of a solid electrolytic capacitor is generally formed by forming a dielectric oxide film layer (2) on an anode substrate (1) made of a metal foil having a large specific surface area that has been subjected to an etching process. A solid semiconductor layer (hereinafter referred to as a solid electrolyte) (4) is formed as an opposing electrode, and a conductor layer (5) such as a conductive paste is preferably formed. Next, such elements are singly or laminated to join the lead wires (6, 7), and the whole is completely sealed with a sealing resin (8) such as an epoxy resin, so that a solid electrolytic capacitor (9) Widely used in electrical products as parts.

  In recent years, with the digitization of electrical equipment and the speeding up of personal computers, small and large-capacitance capacitors and low-impedance capacitors in the high frequency region are required. Recently, it has been proposed to use a conductive polymer having electronic conductivity as a solid electrolyte.

  In general, an electrolytic oxidation polymerization method and a chemical oxidation polymerization method are known as methods for forming a conductive polymer on a dielectric oxide film. The chemical oxidative polymerization method is difficult to control the reaction or the form of the polymer film, but various methods have been proposed because it is easy to form a solid electrolyte and enables mass production in a short time. For example, there is disclosed a method of forming a solid electrolyte having a layered structure by alternately repeating a step of immersing an anode substrate in a solution containing a monomer and a step of immersing in a solution containing an oxidizing agent (Patent Document 1: Patent) No. 3187380). According to this method, a solid electrolytic capacitor having a high capacity, low impedance, and excellent heat resistance can be manufactured by forming a solid electrolyte layer having a layered structure with a film thickness of 0.01 to 5 μm. In order to manifest the characteristics, it is necessary to form a thick solid electrolyte membrane to completely cover the inside and outside surfaces of the capacitor element, and in order to use it as an element for a multilayer capacitor in which a plurality of capacitor elements are stacked. There is a demand for further reduction in the thickness of the entire solid electrolyte layer.

  Various techniques have been disclosed for uniformly forming a solid electrolyte in the pores and on the outer surface of the capacitor element. For example, a method of controlling the thickness of a conductive polymer by controlling the distribution state of the amount of oxidant attached to the anode body on the outer surface of the anode body in the process of forming the conductive polymer is disclosed. (Patent Document 2: JP 2003-188052 A). Further, it is disclosed that formation of a polymer film on the outer peripheral surface, particularly the corner portion is important (Patent Document 3: Japanese Patent Laid-Open No. 2001-143968).

  On the other hand, it is disclosed that the short-circuit defect rate of a solid electrolytic capacitor can be reduced by removing burrs from an electrode foil (Patent Document 4: Japanese Patent Laid-Open No. 1-251605 and Patent Document 5: Japanese Patent Laid-Open No. 2004-296611). ). The burr in Patent Document 4 is a portion that occurs outside the electrode foil that is generated at the time of cutting, and the cut end portion of the electrode foil is pressed by a press in a wedge shape, a convex shape, a substantially semi-elliptical shape, a substantially R shape, and a sloped surface. A method of any combination is disclosed. The molding by pressing destroys the porous layer present in the electrode foil, and the reliability decreases. Moreover, there is no clear description regarding the state of burrs after pressing, the fine structure of the side surface of the electrode foil, the origin of burrs occurring in the electrode foil, and the like. On the other hand, in Patent Document 5, the valve metal foil that has been previously cut is subjected to a chemical conversion treatment and then physically cut to prevent burring of the valve metal foil. This method is effective in preventing the generation of burrs, but a new metal surface is generated at the cut end after cutting. For this reason, this valve metal foil cannot be used as it is as an electrode of a capacitor as it is, and it is necessary to repeat complicated chemical conversion treatment again, which is not an economical method.

Japanese Patent No. 3187380 JP 2003-188052 A JP 2001-143968 A JP-A-1-251605 JP 2004-296611 A

  In order to obtain a solid electrolytic capacitor of a predetermined capacity, usually a plurality of capacitor elements are stacked, an anode lead wire is connected to the anode terminal, a cathode lead wire is connected to a conductor layer containing a conductive polymer, and The whole is encapsulated with an insulating resin such as epoxy resin, but in a solid electrolytic capacitor, the conductive polymer polymerization conditions are controlled at the cathode portion of the capacitor element to increase the thickness of the conductive polymer. There is a need. Unless the polymerization conditions of the conductive polymer on the cathode part of the capacitor element are carefully controlled, the thickness of the conductive polymer becomes non-uniform so that a thin part of the conductive polymer is formed. This is because direct contact with the layer is facilitated, leading to an increase in leakage current. In addition, since the number of capacitor elements that can be stacked on a solid electrolytic capacitor chip of a predetermined size is limited by the thickness of the element, the capacity of the solid electrolytic capacitor chip cannot be increased. In particular, in the capacitor element, the adhesion thickness of the conductive polymer is likely to be uneven at the side surface portion and the edge portion of the end surface, and the capacitor element and the capacitor are laminated in a thin portion of the conductive polymer. There is a problem that the element is likely to be in direct contact and the leakage current is likely to increase.

  Accordingly, an object of the present invention is to solve the above-mentioned problems, to reduce the variation in element shape without increasing short-circuit failure, and to stably produce a thin capacitor element, and to provide a capacitor element in a solid electrolytic capacitor chip. An object of the present invention is to provide a multilayer solid electrolytic capacitor element and a method for manufacturing the same, which can increase the number of stacked layers to increase the capacity and further reduce variations in equivalent series resistance.

  As a result of intensive studies in view of the above problems, the present inventors have found that a method of obliquely cutting an anode substrate having fine holes is effective. In addition, when the anode substrate was cut obliquely, it was found that the valve metal having no fine holes in the anode substrate was stretched to generate protrusions. It is already known that the polymer film at the corner is difficult to form, and further, the projection formed at the corner prevents the formation of the polymer film, and the capacitor element and the capacitor element are easily in direct contact with each other. I found that the rise was happening. In particular, the valve metal that does not have micropores on the anode substrate has a lower ability to retain the solution attached to the surface than the porous layer that has micropores, and therefore further prevents the formation of a polymerized film. It was confirmed.

  Further, the solution can be obtained by having a structure having a groove oblique or parallel to the minor axis direction of the cutting surface formed by stretching the valve metal layer having no micropores of the anode substrate following the cutting blade. It has been found that there is an effect of facilitating the liquid absorption to the surface of the valve metal that does not have the ability to hold and does not have the fine pores, and makes the formation of the polymer film easy and uniform.

  Therefore, the present inventors obliquely cut the anode substrate having micropores, and at this time, a cutting foil in which the portion where the valve metal having no micropores of the anode substrate is stretched does not exceed the outer periphery of the anode substrate. The solid electrolytic capacitor produced by manufacturing the solid electrolytic capacitor used in this way has improved adhesion of the solid electrolyte formed on the dielectric film, high capacity, dielectric loss (tan δ), leakage current, and defect rate. It was confirmed that it became smaller. Furthermore, it was confirmed that the capacitor can be reduced in size and increased in capacity by stacking a plurality of solid electrolytic capacitor elements having excellent characteristics as described above.

（式中、ｙは前記弁金属延伸層の基板厚み方向における厚さ、ｚは前記延伸層と接触している微細孔を有する弁金属層の基板厚み方向における厚さをそれぞれ表わす。）を満たすことを特徴とする前記１に記載の固体電解コンデンサ用陽極基体。
３．陽極基体が平板状または箔状であり、切断開始側の陽極基体表面と切断面との間の稜辺内部の角度が９０°超１３５°以下の範囲内の角度で切断を行なうことにより得られる前記２に記載の固体電解コンデンサ用陽極基体。
４．陽極基体が平板状または箔状であり、弁金属延伸層が陽極基体表面より突出した部分の切断除去を行なって得られる前記２に記載の固体電解コンデンサ用陽極基体。
５．陽極基体が平板状または箔状であり、弁金属延伸層が陽極基体表面より突出した部分を含む稜辺の面取りを行なって得られる前記２に記載の固体電解コンデンサ用陽極基体。
６．陽極基体が平板状または箔状であり、弁金属延伸層が陽極基体表面より突出した部分を含む稜辺に整形部材を押し当てることにより突出を解消して得られる前記２に記載の固体電解コンデンサ用陽極基体。
７．微細孔を有する弁金属層と微細孔を有しない弁金属層とを含む金属基板を斜め切断した陽極基体であって、微細孔を有しない弁金属層が切断刃に追随して引き伸ばされて形成される切断表面の短軸方向に対して斜めもしくは平行な溝を含む前記２に記載の固体電解コンデンサ用陽極基体。
８．斜めもしくは平行な溝の幅が０．１〜１０００μｍを含む前記７に記載の固体電解コンデンサ用陽極基体。
９．斜めもしくは平行な溝のピッチが０．１〜１００μｍを含む前記７に記載の固体電解コンデンサ用陽極基体。
１０．斜めもしくは平行な溝の深さが０．１〜１０μｍである前記７に記載の固体電解コンデンサ用陽極基体。
１１．陽極基体がアルミニウムである前記１〜１０のいずれかに記載の固体電解コンデンサ用陽極基体。
１２．陽極基体が微細孔を有するアルミニウム化成箔を切断機により短冊状に切断し製造されたものである前記１１に記載の固体電解コンデンサ用陽極基体。
１３．前記１〜１２のいずれかに記載の固体電解コンデンサ用陽極基体を含むことを特徴とする固体電解コンデンサ。
１４．微細孔を有する弁作用金属表面に形成された誘電体皮膜上にモノマーを酸化剤により重合させて導電性重合体組成物を含む固体電解質層を設けた固体電解コンデンサの製造方法において、前記１〜１２のいずれかに記載の固体電解コンデンサ用陽極基体を用い、モノマーを含む溶液に浸漬後乾燥する工程（工程１）、酸化剤を含む溶液に浸漬後乾燥する工程（工程２）を含む方法により、誘電体皮膜層を有する弁作用金属に固体電解質層を設けることを特徴とする前記１３に記載の固体電解コンデンサの製造方法。
１５．誘電体皮膜層を有する弁作用金属をモノマー化合物を含む溶液に浸漬後乾燥する工程１、酸化剤を含む溶液に浸漬後乾燥する工程２を複数回繰り返す方法により誘電体皮膜層を有する弁作用金属に固体電解質層を設けることを特徴とする前記１４に記載の固体電解コンデンサの製造方法。
１６．酸化剤が過硫酸塩である前記１４または１５に記載の固体電解コンデンサの製造方法。
１７．酸化剤を含む溶液が有機微粒子を含む懸濁液である前記１４〜１６のいずれかに記載の固体電解コンデンサの製造方法。
１８．有機微粒子の平均粒子径（Ｄ₅₀）が、１〜２０μｍの範囲である前記１７に記載の固体電解コンデンサの製造方法。
１９．有機微粒子が脂肪族スルホン酸化合物、芳香族スルホン酸化合物、脂肪族カルボン酸化合物、芳香族カルボン酸化合物、それらの塩、及びペプチド化合物からなる群から選ばれる少なくとも１種である前記１８に記載の固体電解コンデンサの製造方法。
２０．前記１４〜１９のいずれかに記載の製造方法で製造された固体電解コンデンサ。 That is, the present invention relates to the following anode substrate for a solid electrolytic capacitor, a solid electrolytic capacitor including the same, a method for manufacturing the solid electrolytic capacitor, and a solid electrolytic capacitor manufactured by the manufacturing method.
1. An anode substrate obtained by obliquely cutting a metal substrate including a valve metal layer having micropores and a valve metal layer having no micropores, and the valve metal layer having no micropores is stretched following the cutting blade. An anode substrate for a solid electrolytic capacitor, characterized by having a cut surface.
2. An anode substrate obtained by obliquely cutting a metal substrate including a valve metal layer having micropores and a valve metal layer having no micropores, and the valve metal layer having no micropores is stretched to follow the cutting blade and is fine The extended valve metal layer formed by covering the end surface of the valve metal layer having holes has the following conditional expression:

Where y represents the thickness of the valve metal stretched layer in the substrate thickness direction, and z represents the thickness of the valve metal layer having micropores in contact with the stretched layer in the substrate thickness direction. 2. The anode substrate for a solid electrolytic capacitor as described in 1 above.
3. The anode substrate is in the form of a flat plate or a foil, and is obtained by cutting at an angle in the range of the ridge side between the anode substrate surface on the cutting start side and the cut surface within a range of more than 90 ° and not more than 135 °. 3. The anode substrate for a solid electrolytic capacitor as described in 2 above.
4). 3. The anode substrate for a solid electrolytic capacitor as described in 2 above, wherein the anode substrate has a flat plate shape or a foil shape, and is obtained by cutting and removing a portion where the valve metal stretched layer protrudes from the surface of the anode substrate.
5. 3. The anode substrate for a solid electrolytic capacitor as described in 2 above, wherein the anode substrate is flat or foil-like, and the valve metal stretched layer is obtained by chamfering a ridge including a portion protruding from the surface of the anode substrate.
6). 3. The solid electrolytic capacitor as described in 2 above, wherein the anode substrate is flat or foil-like, and the valve metal stretch layer is obtained by eliminating the protrusion by pressing the shaping member against the ridge including the portion protruding from the surface of the anode substrate. Anode substrate.
7). An anode substrate obtained by obliquely cutting a metal substrate including a valve metal layer having micropores and a valve metal layer having no micropores, and the valve metal layer having no micropores is stretched following the cutting blade. 3. The anode substrate for a solid electrolytic capacitor as described in 2 above, comprising a groove oblique or parallel to the minor axis direction of the cut surface.
8). 8. The anode base for a solid electrolytic capacitor as described in 7 above, wherein the width of the oblique or parallel groove includes 0.1 to 1000 μm.
9. 8. The anode substrate for a solid electrolytic capacitor as described in 7 above, wherein the pitch of the oblique or parallel grooves includes 0.1 to 100 μm.
10. 8. The anode substrate for a solid electrolytic capacitor as described in 7 above, wherein the depth of the oblique or parallel groove is 0.1 to 10 μm.
11. 11. The anode substrate for a solid electrolytic capacitor as described in any one of 1 to 10 above, wherein the anode substrate is aluminum.
12 12. The anode substrate for a solid electrolytic capacitor as described in 11 above, wherein the anode substrate is produced by cutting an aluminum formed foil having fine holes into a strip shape with a cutting machine.
13. A solid electrolytic capacitor comprising the anode substrate for a solid electrolytic capacitor according to any one of 1 to 12 above.
14 In the method for producing a solid electrolytic capacitor in which a monomer is polymerized with an oxidizing agent on a dielectric film formed on a valve action metal surface having micropores, and a solid electrolyte layer containing a conductive polymer composition is provided, Using the anode substrate for a solid electrolytic capacitor according to any one of 12 above, a method including a step of drying after immersion in a solution containing a monomer (step 1) and a step of drying after immersion in a solution containing an oxidizing agent (step 2) 14. The method for producing a solid electrolytic capacitor as described in 13 above, wherein a solid electrolyte layer is provided on the valve action metal having a dielectric film layer.
15. Valve action metal having a dielectric coating layer by a method of repeating step 1 of immersing a valve action metal having a dielectric coating layer in a solution containing a monomer compound and drying, and step 2 of immersing and drying in a solution containing an oxidant a plurality of times 15. The method for producing a solid electrolytic capacitor as described in 14 above, wherein a solid electrolyte layer is provided on the solid electrolytic layer.
16. 16. The method for producing a solid electrolytic capacitor as described in 14 or 15 above, wherein the oxidizing agent is persulfate.
17. 17. The method for producing a solid electrolytic capacitor as described in any one of 14 to 16, wherein the solution containing the oxidizing agent is a suspension containing organic fine particles.
18. 18. The method for producing a solid electrolytic capacitor as described in 17 above, wherein the organic fine particles have an average particle diameter (D ₅₀ ) in the range of 1 to 20 μm.
19. 19. The organic fine particles as described in 18 above, which are at least one selected from the group consisting of aliphatic sulfonic acid compounds, aromatic sulfonic acid compounds, aliphatic carboxylic acid compounds, aromatic carboxylic acid compounds, salts thereof, and peptide compounds. A method for producing a solid electrolytic capacitor.
20. The solid electrolytic capacitor manufactured by the manufacturing method in any one of said 14-19.

  According to the present invention, there is less short circuit failure, less variation in element shape, and a thin capacitor element can be stably manufactured. It is possible to provide a solid electrolytic capacitor element suitable for a multilayer solid electrolytic capacitor having a small variation.

Hereinafter, the present invention will be described with reference to the accompanying drawings.
The anode substrate of the present invention is an anode substrate obtained by obliquely cutting a metal substrate including a valve metal layer having fine holes and a valve metal layer having no fine holes, and the valve metal layer having no fine holes serves as a cutting blade. A metal substrate having a cutting surface formed by being stretched and following, typically including a valve metal having no micropores in the center and a valve metal layer having micropores on the outer periphery, preferably It is a flat or foil-like anode substrate.
That is, the cross-sectional shape in the thickness direction in a typical example is as shown in FIG.

In FIG. 1, A ₁ and A ₂ are valve metal layers having micropores (hereinafter also referred to as microporous layers), B is a valve metal layer having no micropores, and e is the cutting layer of the B layer. It is the valve metal extending | stretching layer (henceforth a valve metal extending | stretching layer) which has the cut surface formed by being followed and extended. X is the original thickness (that is, only the unstretched portion) of the valve metal layer (the B layer) having no micropores, y is the thickness of the stretched layer e in the substrate thickness direction, and z is the micropore. The thickness of the valve metal layer (the side in contact with the stretched layer, that is, A ₂ ) in the substrate thickness direction. When the anode substrate is cut in the direction of the arrow in FIG. 1, the end face of the relatively soft B layer is dragged by the cutting blade, and is stretched along with it, and the valve metal stretched layer having a cut surface formed as shown in FIG. yields e.
In addition, the valve metal stretched layer (or burr) in the present invention does not substantially include a valve metal layer having micropores, and is formed by stretching the valve metal layer having no micropores following the cutting blade. A valve metal stretch layer having a cut surface.

を満たす必要がある。好ましくは０≦ｙ／ｚ＜１、より好ましくは０≦ｙ／ｚ≦0.95、さらに好ましくは０≦ｙ／ｚ≦0.90である。 In this invention, this valve metal extending | stretching layer e is the following conditional expression:

It is necessary to satisfy. Preferably 0 ≦ y / z <1, more preferably 0 ≦ y / z ≦ 0.95, and still more preferably 0 ≦ y / z ≦ 0.90.

In general, a porous body having micropores is chemically oxidized by adhering or absorbing a monomer solution and an oxidant solution to the pores existing on the surface by a method such as immersion or spraying, and maintaining the state. Polymerization occurs to form a polymerized film. However, the valve metal layer that does not have micropores is agglomerated locally because the surface of the monomer solution and oxidant solution adhered to the surface by dipping or spraying is smooth (smooth). It was discovered that the solution was not retained because it was dripping down and efficient chemical oxidative polymerization did not proceed. The groove of the cut surface formed in the present invention improves the solution holding ability of the monomer solution and the oxidant solution on the surface by roughening the smooth surface of the valve metal layer having no micropores. The present inventors have found that it is effective to efficiently advance the formation of a polymer film on a valve metal surface or corner portion that does not have micropores, which has been difficult in the past. In addition, the cutting surface formed in this invention includes the cutting surface of the valve metal extending | stretching layer which does not have the micropore which has the cutting surface.
That is, the valve metal layer having no micropores included in the anode body obtained by obliquely cutting the metal substrate including the valve metal layer having micropores and the valve metal layer having no micropores of the present invention is It is preferable that the cutting surface formed by being dragged and followed by the cutting blade includes a groove, and more preferably includes a groove oblique or parallel to the minor axis direction of the cutting surface. More specifically, it is preferably 0 ° to 80 °, more preferably 0 ° to 45 °, particularly preferably 0 ° to 30 ° with respect to the minor axis direction of the cut surface. It is an oblique or parallel groove. If this oblique or parallel groove exceeds 80 degrees with respect to the minor axis direction of the cutting surface, the ability to hold the solution is no longer preferable.

  The width of the groove on the cut surface formed in the present invention is preferably 0.1 to 1000 μm, more preferably 0.1 to 100 μm, and particularly preferably 0.1 to 10 μm. If the width of the groove exceeds 1000 μm, the width becomes too wide and the solution holding ability can no longer be expected. When the width of the groove is less than 0.1 μm, the surface becomes substantially the same as a smooth surface, which is not preferable.

  The pitch of the grooves on the cut surface formed in the present invention is preferably 0.1 to 1000 μm, more preferably 0.1 to 100 μm, and particularly preferably 0.1 to 10 μm. If the pitch of the grooves exceeds 1000 μm, the distance between the grooves becomes too wide, and a synergistic effect of solution retention that increases as the number of grooves increases cannot be expected. If the pitch of the grooves is less than 0.1 μm, the surface becomes substantially the same as a smooth surface, which is not preferable.

  Although the depth of the groove on the cut surface formed in the present invention differs depending on the thickness of the anode substrate, it cannot be specified, but is preferably in the range of 0.1 to 100 μm, more preferably 0.1 to 10 μm. The depth of this groove is preferably in the range of 1 to 10% of the thickness of the anode substrate.

  The groove on the cutting surface formed in the present invention can be formed by forming a desired minute groove in the disk-shaped blade unit used for cutting the blade surface of the disk-shaped blade unit. Further, it can be formed by attaching fine powder to the blade surface of the disk-shaped blade unit. The groove of the blade used in the production of the anode substrate of the present invention is preferably formed on the outer peripheral surface or the ridge portion formed by the outer peripheral surface and the disk plane.

The width of the groove of the blade used in the production of the anode substrate of the present invention is preferably 0.1 to 100 μm. More preferably, it is 0.1-10 micrometers.

  It is preferable that the pitch of the groove | channel of the blade used by manufacture of the anode base | substrate of this invention is 0.1-100 micrometers. More preferably, it is 0.1-10 micrometers.

  The depth of the groove of the blade used in the production of the anode substrate of the present invention is preferably 0.01 to 10 μm, more preferably 0.1 to 1 μm. The groove depth is preferably in the range of 0.01 to 5% of the thickness of the anode substrate.

Furthermore, the groove on the cut surface of the anode substrate can also be formed by attaching fine powder to the blade surface of the disk blade unit. FIG. 10 is an enlarged photograph of a cut surface having a structure in which grooves formed on the cut surface of the aluminum conversion foil are present by attaching powder and cutting. More specifically, the powder used in the present invention is preferably the same material as that constituting the anode substrate, and its oxide or nitride is more preferred. In the case of using aluminum as a base material, aluminum oxide (alumina) or aluminum powder having an oxide film on the surface can be exemplified. In the case of tantalum, niobium, etc., tantalum oxide, niobium oxide, etc. can be mentioned as examples.
When fine powder is attached to the blade surface of the disk-shaped blade unit and cut, the size of the groove may be partially larger than the powder diameter used to agglomerate and form secondary particles. However, it can be used without any particular problem in the present invention.

  The powder used in the present invention preferably has a secondary particle size or primary particle size in the range of 0.01 to 10 μm, and more preferably in the range of 0.01 to 1 μm.

The metal having a valve action that can be used in the present invention is a simple metal such as aluminum, tantalum, niobium, titanium, zirconium, magnesium, silicon, or an alloy thereof, and aluminum is particularly preferable. The porous form may be any form as long as it is a form of a porous molded body such as an etched product of a rolled foil or a fine powder sintered body.
As the anode substrate, a porous sintered body of these metals, a plate (including a ribbon, a foil, etc.) surface-treated by etching or the like, a wire or the like can be used, but preferably a flat plate or a foil. More preferably, the aluminum chemical conversion foil having fine holes is manufactured by cutting into strips with a cutting machine.

  The thickness (H) of the valve action metal foil (anode substrate) varies depending on the purpose of use, but usually a foil having a thickness of about 40 to 300 μm is used. In order to obtain a thin solid electrolytic capacitor, for example, an aluminum foil having a thickness of 80 to 250 μm is preferably used, and the maximum height of the element provided with the solid electrolytic capacitor is preferably 250 μm or less. Although the size and shape of the metal foil vary depending on the application, a rectangular element having a width of about 1 to 50 mm and a length of about 1 to 50 mm is preferable as a flat element unit, more preferably about 2 to 15 mm in width and about 2 in length. ~ 25 mm.

In order to realize the above-mentioned conditions in such an anode substrate, for example, the following methods can be mentioned, but the invention is not limited thereto.
(1) The angle inside the edge between the surface of the anode substrate on the cutting start side and the cut surface (that is, the complementary angle of the cutting angle indicated by angle α in FIG. 1) is in the range of more than 90 ° and less than 135 ° Cut at an angle of.
(2) When the extended part of the valve metal has a protruding part from the surface of the anode substrate, the protruding part is cut.
(3) When the extended part of the valve metal has a protruding part from the surface of the anode substrate, chamfering of the edge including the protruding part is performed.
(4) When the extended part of the valve metal layer has a protruding part from the surface of the anode substrate, the protruding part is eliminated by pressing the shaping member against the edge including the protruding part.
(1)-(3) can be implemented by using the cutting machine which piled up two blades, for example. In particular, (1) is by arranging a plurality of disk-shaped blade units consisting of two blades, a thick blade and a thin blade, with a small gap between them, so that the thick blade of one disk-shaped blade unit and others 1 to 15 with respect to the cutting direction of the blades by using a slitter capable of cutting between the thin blades of the disk-shaped blade unit and passing the anode base plate between the alternately arranged disk-shaped blade units. This can be realized by adjusting the gap so as to be discharged in a direction inclined.

The present invention further provides a solid electrolytic capacitor including the above-described anode substrate. A typical structure is shown in FIG. In this case, the dielectric film (2) on the surface of the anode substrate (1) is usually obtained by chemical conversion treatment of a metal porous molded body having a valve action, and further forming a solid electrolyte (4) (cathode portion). .
As a method for forming the dielectric oxide film on the surface of the porous metal body, a known method can be used. For example, when an aluminum foil is used, an oxide film can be formed by anodizing in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or a sodium salt or an ammonium salt thereof. Moreover, when using the sintered compact of a tantalum powder, it can anodize in phosphoric acid aqueous solution and can form an oxide film in a sintered compact.

  Chemical conversion conditions such as chemical conversion liquid and chemical conversion voltage used for chemical conversion are confirmed in advance by experiments and set to appropriate values according to the capacity, withstand voltage, etc. required for the solid electrolytic capacitor to be produced. In addition, in the chemical conversion treatment, the chemical conversion solution is prevented from spreading to the portion that becomes the anode of the solid electrolytic capacitor, and the insulation from the solid electrolyte (4) (cathode portion) formed in the subsequent process is ensured. Generally, masking (3) is provided.

  As a masking material, a general heat resistant resin, preferably a heat resistant resin which can be dissolved or swelled in a solvent or a precursor thereof, a composition comprising inorganic fine powder and a cellulose resin, etc. can be used, but the material is not limited. . Specific examples include polyphenylsulfone (PPS), polyethersulfone (PES), cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, etc.), low molecular weight polyimides and their Examples thereof include derivatives and precursors thereof, and low molecular weight polyimides, polyethersulfones, fluororesins and their precursors are particularly preferable.

  The present invention is based on chemical oxidative polymerization of an organic polymer monomer including a step of immersing a valve metal porous substrate in an oxidant solution and then drying to gradually increase the oxidant solution concentration on the substrate. In the chemical oxidative polymerization method of the present invention, a monomer is deposited on the dielectric film having fine pores of the anode substrate, and oxidative polymerization is caused in the presence of a compound that can be a dopant of the conductive polymer. A composition is formed on the dielectric surface as the solid electrolyte.

The solid electrolyte layer of the conductive polymer formed by the method of the present invention has a fibril structure or a lamellar (thin layered) structure, and in such a structure, there is a wide overlap between polymer chains. In the present invention, the total thickness of the solid electrolyte layer is in the range of about 10 to about 100 μm, the space of the layer structure of the polymer is 0.01 to 5 μm, preferably 0.05 to 3 μm, more preferably 0.1 to 2 μm, By setting the space occupancy ratio between the layers of the solid electrolyte in the entire polymer film within the range of 0.1 to 20%, the electron hopping between polymer chains is facilitated, the electrical conductivity is improved, and the characteristics such as low impedance are improved. I found out.
Hereinafter, a method for forming a solid electrolyte layer on a dielectric film formed on the surface of a valve metal having fine holes in the present invention will be described in order.

  Step 1 of immersing in the solution containing the monomer and drying in the present invention is performed in order to supply the monomer onto the dielectric surface and the polymer composition. Further, in order to uniformly deposit the monomer on the dielectric surface and the polymer composition, after impregnating the monomer-containing liquid, the solvent is allowed to evaporate by being left in the air for a certain period of time. This condition varies depending on the type of solvent, but is generally performed at a temperature from 0 ° C. or higher to the boiling point of the solvent. The standing time varies depending on the type of the solvent, but it is generally about 5 seconds to 15 minutes, for example, within 5 minutes for alcohol solvents. By providing this standing time, the monomer can uniformly adhere to the surface of the dielectric, and contamination during immersion in the oxidizing agent-containing liquid in the next step can be reduced.

  The monomer supply can be controlled by the type of solvent used in the solution containing the monomer, the concentration of the monomer-containing liquid, the solution temperature, the immersion time, and the like.

The immersion time applied in step 1 is a time sufficient for the monomer component in the contained liquid to adhere to the dielectric surface of the metal foil substrate to a time not less than 15 minutes, preferably 0.1 seconds to 10 minutes, more preferably 1 second to 7 minutes.
Moreover, -10-60 degreeC is preferable and, as for immersion temperature, 0-40 degreeC is especially preferable. If it is less than −10 ° C., it takes time for the solvent to volatilize and the reaction time becomes long, which is not preferable. If it exceeds 60 ° C., the volatilization of the solvent and the monomer cannot be ignored and the concentration control becomes difficult.

  The concentration of the monomer-containing liquid is not particularly limited, and an arbitrary concentration can be used. However, it is preferably 3 to 70% by mass, more preferably 25 to 25%, which is excellent in impregnation into the fine pores of the valve action metal. Used at 45% by weight.

  Examples of the solvent of the solution used in Step 1 include ethers such as tetrahydrofuran (THF), dioxane, and diethyl ether; ketones such as acetone and methyl ethyl ketone; dimethylformamide, acetonitrile, benzonitrile, and N-methylpyrrolidinone (NMP). Aprotic polar solvents such as dimethyl sulfoxide (DMSO); esters such as ethyl acetate and butyl acetate; non-aromatic chlorinated solvents such as chloroform and methylene chloride; nitro compounds such as nitromethane, nitroethane, and nitrobenzene; methanol Further, alcohols such as ethanol and propanol, water, or a mixed solvent thereof can be used. Preferably, alcohols or ketones or a mixed system thereof is desirable.

  In the present invention, the monomer is oxidatively polymerized by immersing in an oxidant-containing solution and maintaining in a predetermined temperature range in air for a predetermined time in step 2, but in order to make the polymer film more dense, A method mainly comprising oxidative polymerization held in The temperature maintained in air varies depending on the type of monomer, but may be, for example, 5 ° C. or lower for pyrrole and about 30 to 60 ° C. for thiophene.

  The polymerization time depends on the amount of monomer attached during immersion. The amount of adhesion varies depending on the concentration and viscosity of the monomer and oxidant-containing liquid, so it cannot be specified unconditionally. Generally, if the amount of adhesion is reduced once, the polymerization time can be shortened, and if the amount of adhesion is increased. Longer polymerization times are required. In the method of the present invention, one polymerization time is 10 seconds to 30 minutes, preferably 3 to 15 minutes.

  The dipping time applied as step 2 is a time sufficient for the oxidant component to adhere to the dielectric surface of the metal foil substrate to a time not shorter than 15 minutes, preferably 0.1 seconds to 10 minutes, more preferably 1 second to 7 minutes.

Examples of the oxidizing agent used in step 2 include an aqueous oxidizing agent and an organic solvent oxidizing agent. Examples of the aqueous oxidizing agent preferably used in the present invention include peroxodisulfuric acid and its Na salt, K salt, NH ₄ salt, cerium (IV) nitrate, cerium (IV) ammonium nitrate, iron (III) sulfate, nitric acid Examples thereof include iron (III) and iron (III) chloride. Examples of the organic solvent-based oxidizing agent include ferric salts of organic sulfonic acids such as iron (III) dodecylbenzenesulfonate and iron (III) p-toluenesulfonate.
Examples of the solvent of the solution used in Step 2 of the present invention include ethers such as tetrahydrofuran (THF), dioxane, and diethyl ether; ketones such as acetone and methyl ethyl ketone; dimethylformamide, acetonitrile, benzonitrile, N-methylpyrrolidinone ( NMP), aprotic polar solvents such as dimethyl sulfoxide (DMSO); alcohols such as methanol, ethanol, propanol, water, or a mixed solvent thereof can be used. Preferably, water, alcohols or ketones or a mixed system thereof is desirable.

  The concentration of the oxidant solution is preferably 5 to 50% by mass, and the temperature of the oxidant solution is preferably −15 to 60 ° C.

  In step 2, a suspension containing organic fine particles is more preferably used. The organic fine particles remain on the dielectric surface or the polymer composition, and thus are effective for assisting the supply of the oxidant and the monomer to the smooth polymer film surface filled with the polymer film in the pores. In particular, after forming the solid electrolyte layer by using soluble organic fine particles, the soluble organic fine particles can be dissolved and removed, and the reliability of the capacitor element can be improved.

  Solvents used in the process of dissolving and removing the organic fine particles include water; alcohols such as methanol, ethanol and propanol; ketones such as acetone and methyl ethyl ketone; and non- solvents such as dimethylformamide, N-methyl-2-pyrrolidinone and dimethyl sulfoxide. A protic polar solvent is used, but water, alcohols, or a mixed solvent thereof is preferable, and a solvent that also dissolves the oxidizing agent is more preferable because it can be performed simultaneously with the removal of the oxidizing agent.

Soluble inorganic fine particles that can be removed by using a strong acid are not preferable because they cause damage such as dissolution or corrosion of the dielectric film on the surface of the valve metal.
The soluble organic fine particles preferably have an average particle diameter (D ₅₀ ) in the range of 0.1 to 20 μm, and more preferably 0.5 to 15 μm. If the average particle diameter (D ₅₀ ) of the soluble organic fine particles exceeds 20 μm, the gap formed in the polymerized film becomes large, which is not preferable. If the average particle diameter is less than 0.1 μm, the effect of increasing the adhesion liquid disappears and becomes equivalent to water.

  Specific examples of the soluble organic fine particles include an aliphatic sulfonic acid compound, an aromatic sulfonic acid compound, an aliphatic carboxylic acid compound, an aromatic carboxylic acid compound, a peptide compound, and / or a salt thereof. Acid compounds, aromatic carboxylic acid compounds, and peptide compounds are preferably used.

More specifically, aromatic sulfonic acid compounds include benzene sulfonic acid, toluene sulfonic acid, naphthalene sulfonic acid, anthracene sulfonic acid, anthraquinone sulfonic acid and / or salt thereof, and more specifically, aromatic carboxylic acid compounds include benzoic acid. More specific examples of the acid, toluene carboxylic acid, naphthalene carboxylic acid, anthracene carboxylic acid, anthraquinone carboxylic acid or / and salts thereof, and peptide compounds include surfactin, iturin, prepastatin, and serauchen.
In the method of the present invention, it is necessary to control the number of impregnations so that the conductive polymer composition to be formed has a thickness resistant to humidity, heat, stress, and the like.

  One of the preferable formation steps of the solid electrolyte according to the present invention is a method in which the steps 1 and 2 are repeated as one cycle. A desired solid electrolyte layer can be formed by repeating the cycle three times or more, preferably 8 to 30 times, for one anode substrate. Step 1 and step 2 may be performed in reverse order.

  According to the present invention, an aluminum foil having a dielectric oxide film is impregnated, for example, in an isopropyl alcohol (IPA) solution of 3,4-ethylenedioxythiophene (EDT), as shown in the following examples. After substantially drying IPA to remove IPA, impregnation with about 20% by mass of an oxidizing agent (ammonium persulfate) aqueous solution, followed by heating at about 40 ° C. for 10 minutes, and by repeating this step, poly (3 , 4-ethylenedioxythiophene) polymer can be obtained.

  The conductive polymer forming the solid electrolyte used in the present invention is a polymer of an organic polymer monomer having a π-electron conjugated structure, and the degree of polymerization is 2 or more and 2000 or less, more preferably 3 or more and 1000 or less, and still more preferably 5 It is 200 or less. As specific examples, a conductive polymer containing a structure represented by a compound having a thiophene skeleton, a compound having a polycyclic sulfide skeleton, a compound having a pyrrole skeleton, a compound having a furan skeleton, a compound having an aniline skeleton, or the like as a repeating unit. Is mentioned.

  Examples of the monomer having a thiophene skeleton include 3-methylthiophene, 3-ethyloffene, 3-propylthiophene, 3-butylthiophene, 3-pentylthiophene, 3-hexylthiophene, 3-heptylthiophene, 3-octylthiophene, 3-nonylthiophene, 3-decylthiophene, 3-fluorothiophene, 3-chlorothiophene, 3-bromothiophene, 3-cyanothiophene, 3,4-dimethylthiophene, 3,4-diethylthiophene, 3,4-butylenethiophene , Derivatives of 3,4-methylenedioxythiophene, 3,4-ethylenedioxythiophene, and the like. These compounds can be prepared by commercially available compounds or by known methods (for example, Synthetic Metals, 1986, Vol. 15, 169).

  Specific examples of the monomer having a polycyclic sulfide skeleton include compounds having a 1,3-dihydropolycyclic sulfide (also known as 1,3-dihydrobenzo [c] thiophene) skeleton, 1,3-dihydronaphtho [2,3 -C] A compound having a thiophene skeleton can be used. Furthermore, a compound having a 1,3-dihydroanthra [2,3-c] thiophene skeleton and a compound having a 1,3-dihydronaphthaseno [2,3-c] thiophene skeleton can be given. These can be prepared by a known method, for example, the method described in JP-A-8-3156.

  A compound having a 1,3-dihydronaphtho [1,2-c] thiophene skeleton is a 1,3-dihydrophenanthra [2,3-c] thiophene derivative or 1,3-dihydrotriphenylo [2]. , 3-c] thiophene skeleton, 1,3-dihydrobenzo [a] anthraceno [7,8-c] thiophene derivatives and the like can also be used.

  A compound optionally containing nitrogen or N-oxide in the condensed ring can also be used, such as 1,3-dihydrothieno [3,4-b] quinoxaline, 1,3-dihydrothieno [3,4-b] quinoxaline- 4-oxide, 1,3-dihydrothieno [3,4-b] quinoxaline-4,9-dioxide and the like can be mentioned.

  Examples of the monomer having a pyrrole skeleton include 3-methylpyrrole, 3-ethylpyrrole, 3-propylpyrrole, 3-butylpyrrole, 3-pentylpyrrole, 3-hexylpyrrole, 3-heptylpyrrole, 3-octylpyrrole, 3-nonylpyrrole, 3-decylpyrrole, 3-fluoropyrrole, 3-chloropyrrole, 3-bromopyrrole, 3-cyanopyrrole, 3,4-dimethylpyrrole, 3,4-diethylpyrrole, 3,4-butylenepyrrole , Derivatives of 3,4-methylenedioxypyrrole, 3,4-ethylenedioxypyrrole, and the like. These compounds can be prepared commercially or by known methods.

  Examples of the monomer having a furan skeleton include 3-methylfuran, 3-ethylfuran, 3-propylfuran, 3-butylfuran, 3-pentylfuran, 3-hexylfuran, 3-heptylfuran, 3-octylfuran, 3-nonylfuran, 3-decylfuran, 3-fluorofuran, 3-chlorofuran, 3-bromofuran, 3-cyanofuran, 3,4-dimethylfuran, 3,4-diethylfuran, 3,4-butylenefuran, 3,4 -Derivatives such as methylenedioxyfuran and 3,4-ethylenedioxyfuran can be mentioned. These compounds can be prepared commercially or by known methods.

  Examples of the monomer having an aniline skeleton include 2-methylaniline, 2-ethylaniline, 2-propylaniline, 2-butylaniline, 2-pentylaniline, 2-hexylaniline, 2-heptylaniline, 2-octylaniline, 2-nonylaniline, 2-decylaniline, 2-fluoroaniline, 2-chloroaniline, 2-bromoaniline, 2-cyanoaniline, 2,5-dimethylaniline, 2,5-diethylaniline, 2,3-butyleneaniline , Derivatives of 2,3-methylenedioxyaniline, 2,3-ethylenedioxyaniline, and the like. These compounds can be prepared commercially or by known methods.

  Among these, compounds having a thiophene skeleton or a polycyclic sulfide skeleton are preferable, and 3,4-ethylenedioxythiophene (EDT) and 1,3-dihydroisothianaphthene are particularly preferable.

There is no restriction | limiting in particular in the polymerization conditions etc. of the compound selected from the said compound group, It can implement easily, after confirming preferable conditions beforehand by simple experiment.
In addition, a compound selected from the above monomer group may be used in combination to form a solid electrolyte as a copolymer. The composition ratio of the polymerizable monomer at that time depends on the polymerization conditions and the like, and the preferred composition ratio and polymerization conditions can be confirmed by a simple test.
For example, a method in which the EDT monomer and the oxidizing agent are preferably applied in the form of a solution and applied separately or together to the oxide film layer of the metal foil can be used (Patent No. 3040113, US Pat. 6229689).

  3,4-ethylenedioxythiophene (EDT) preferably used in the present invention dissolves well in the above monohydric alcohol, but is not well-suited with water, so when brought into contact with a high concentration aqueous oxidant solution, In the EDT, polymerization proceeds satisfactorily at the interface, and a conductive polymer solid electrolyte layer having a fibril structure or a lamellar (thin layered) structure is formed.

  In the production method of the present invention, as a solvent for washing after formation of the solid electrolyte, for example, ethers such as tetrahydrofuran (THF), dioxane and diethyl ether; ketones such as acetone and methyl ethyl ketone; dimethylformamide, acetonitrile, benzonitrile, N -Aprotic polar solvents such as methylpyrrolidinone (NMP) and dimethyl sulfoxide (DMSO); esters such as ethyl acetate and butyl acetate; non-aromatic chlorinated solvents such as chloroform and methylene chloride; nitromethane, nitroethane, and nitrobenzene Nitro compounds such as: alcohols such as methanol, ethanol, propanol, etc .; organic acids such as formic acid, acetic acid, propionic acid; acid anhydrides of the organic acids (eg, acetic anhydride, etc.) or water or mixed solvents thereof Can do. Preferably, water, alcohols or ketones or a mixed system thereof is desirable.

The electrical conductivity of the solid electrolyte thus produced is in the range of about 0.1 to about 200 S / cm, preferably about 1 to about 150 S / cm, more preferably about 10 to about 100 S / cm. It is.
On the conductive polymer composition layer thus formed, it is preferable to provide a conductor layer in order to improve electrical contact with the cathode lead terminal. The conductor layer is formed by, for example, a conductive paste, plating, vapor deposition, or a conductive resin film.

In the present invention, the conductive layer can be compressed after being formed. For example, in the case of a conductor layer containing an elastic body, it can be plastically deformed by compression to make it thinner, and has the effect of smoothing the surface of the conductor layer.
As shown in FIG. 3, the solid electrolytic capacitor element thus obtained is usually formed by laminating a plurality of them and connecting the anode lead wire (6) to the anode terminal, and the conductor layer on the solid electrolyte layer (4) ( A cathode lead wire (7) is connected to an unillustrated), and further, for example, a resin mold (8), a resin case, a metal outer case, an outer case made of resin dipping, etc. Capacitor (9) Product.

  The present invention will be described in more detail below with typical examples. Note that these are illustrative examples, and the present invention is not limited to these.

Example 1:
In FIG. 1, an aluminum conversion foil having x of 30 μm, y / z = 0.3, a complementary angle of the cutting angle α (see FIG. 1) of 110 °, and an overall thickness (H) of 110 μm was used. An enlarged photograph of the cross-sectional shape is shown in FIG. An enlarged photograph of the cut surface is shown in FIG. This aluminum conversion foil was cut into a minor axis direction of 3 mm x a major axis direction of 10 mm, and a polyimide solution having a width of 1 mm was applied on both sides in a circumferential shape so as to divide the major axis direction into 4 mm and 5 mm portions, and then masked. . A 3 mm × 4 mm portion of this chemical conversion foil was formed into a cut portion by applying a voltage of 4 V with a 10 mass% ammonium adipate aqueous solution to form a dielectric oxide film. Next, a 3 mm × 4 mm portion of this aluminum foil was impregnated for 5 seconds with a 2.0 mol / L isopropyl alcohol (IPA) solution in which 3,4-ethylenedioxythiophene was dissolved, and this was dried at room temperature for 5 minutes. Then, it was immersed in a 1.5 mol / L ammonium persulfate aqueous solution adjusted so that sodium 2-anthraquinone sulfonate (D ₅₀ = 11 μm; measured using a master sizer manufactured by Sysmex Corporation) was 0.07% by mass for 5 seconds. . Subsequently, the aluminum foil was left in the atmosphere at 40 ° C. for 10 minutes for oxidative polymerization. Furthermore, the solid electrolyte layer of the conductive polymer was formed on the outer surface of the aluminum foil so that the dipping process and the polymerization process were performed 22 times in total. The finally produced poly (3,4-ethylenedioxythiophene) was washed in 50 ° C. warm water, and then dried at 100 ° C. for 30 minutes to form a solid electrolyte layer.
The film thickness of the corner portion (cut portion with a ridge side internal angle of 110 °) observed by a microscope of the cross-sectional shape was 22 μm. Next, a 3 mm × 4 mm portion on which the solid electrolyte layer was formed was immersed in a 15% by mass ammonium adipate solution, and an anode contact was provided on the valve-acting metal foil in the portion where the solid electrolyte layer was not formed. A voltage of V was applied to perform re-chemical conversion.

  Next, as shown in FIG. 3, carbon paste and silver paste were attached to the portion where the conductive polymer composition layer of the aluminum foil was formed, and the four aluminum foils were laminated, and the cathode lead terminals were connected. Moreover, the anode lead terminal was connected to the part in which the conductive polymer composition layer was not formed by welding. Furthermore, after sealing this laminated element with an epoxy resin, a rated voltage (2 V) was applied at 125 ° C. and aging was performed for 2 hours to complete a total of 30 capacitors.

  With respect to these 30 multilayer capacitor elements, the capacity and loss factor (tan δ × 100 (%)) at 120 Hz, equivalent series resistance (ESR), and leakage current were measured as initial characteristics. The leakage current was measured 1 minute after applying the rated voltage. Table 1 shows the average value of these measured values and the defective rate when a leakage current of 0.002 CV or more is regarded as a defective product. Here, the average value of the leakage current is a value calculated excluding defective products.

Example 2:
In FIG. 1, an aluminum conversion foil having x of 30 μm, y / z = 0.5, a complementary angle of the cutting angle α (see FIG. 1) of 110 °, and an overall thickness (H) of 110 μm was used. An enlarged photograph of the cross-sectional shape is shown in FIG. A solid electrolyte was formed in the same manner as in Example 1 except that this aluminum conversion foil was used.
The film thickness of the corner portion (cut portion with a ridge side internal angle of 110 °) measured in the same manner as in Example 1 was 19 μm.

  Next, re-chemical conversion, application of carbon paste and silver paste, lamination, connection of cathode lead terminals, sealing with an epoxy resin, and aging operation were carried out in the same manner as in Example 1 to complete a total of 30 capacitors. Table 1 shows the results of the characteristic evaluation performed on the obtained multilayer capacitor element in the same manner as in Example 1.

Example 3:
In FIG. 1, an aluminum chemical conversion foil having x of 30 μm, y / z = 0.8, a complementary angle of the cutting angle α (see FIG. 1) of 110 °, and an overall thickness (H) of 110 μm was used. An enlarged photograph of the cross-sectional shape is shown in FIG. A solid electrolyte was formed in the same manner as in Example 1 except that this aluminum conversion foil was used.
The film thickness of the corner portion (cut portion with a ridge side internal angle of 110 °) measured in the same manner as in Example 1 was 17 μm.

  Next, re-chemical conversion, application of carbon paste and silver paste, lamination, connection of cathode lead terminals, sealing with an epoxy resin, and aging operation were carried out in the same manner as in Example 1 to complete a total of 30 capacitors. Table 1 shows the results of the characteristic evaluation performed on the obtained multilayer capacitor element in the same manner as in Example 1.

Example 4:
In FIG. 1, an aluminum conversion foil having x of 30 μm, y / z = 1.0, a complementary angle (see FIG. 1) of the cutting angle α of 110 °, and an overall thickness (H) of 110 μm was used. An enlarged photograph of the cross-sectional shape is shown in FIG. A solid electrolyte was formed in the same manner as in Example 1 except that this aluminum conversion foil was used. In addition, this aluminum conversion foil was manufactured by pressing the aluminum conversion foil cut | disconnected in strip shape and wound up on the rotating shaft to a flat plate with a cut surface down, and bending and removing a projection part.
The film thickness of the corner portion (cut portion with a ridge side internal angle of 110 °) measured in the same manner as in Example 1 was 15 μm.

  Next, re-chemical conversion, application of carbon paste and silver paste, lamination, connection of cathode lead terminals, sealing with an epoxy resin, and aging operation were carried out in the same manner as in Example 1 to complete a total of 30 capacitors. Table 1 shows the results of the characteristic evaluation performed on the obtained multilayer capacitor element in the same manner as in Example 1.

Example 5:
In FIG. 1, an aluminum chemical conversion foil having x of 30 μm, y / z = 0.5, a complementary angle of the cutting angle α (see FIG. 1) of 100 °, and an overall thickness (H) of 110 μm was used. A solid electrolyte was formed in the same manner as in Example 1 except that this aluminum conversion foil was used.
The film thickness of the corner portion (cut portion having a ridge side internal angle of 100 °) measured in the same manner as in Example 1 was 21 μm.

  Next, re-chemical conversion, application of carbon paste and silver paste, lamination, connection of cathode lead terminals, sealing with an epoxy resin, and aging operation were carried out in the same manner as in Example 1 to complete a total of 30 capacitors. Table 1 shows the results of the characteristic evaluation performed on the obtained multilayer capacitor element in the same manner as in Example 1.

Comparative Example 1:
In FIG. 1, an aluminum conversion foil having x of 30 μm, y / z = 1.2, a complementary angle of the cutting angle α (see FIG. 1) of 110 °, and an overall thickness (H) of 110 μm was used. An enlarged photograph of the cross-sectional shape is shown in FIG. A solid electrolyte was formed in the same manner as in Example 1 except that this aluminum conversion foil was used.
The film thickness of the corner portion (cut portion with a ridge side internal angle of 110 °) measured in the same manner as in Example 1 was 3 μm.

  Next, re-chemical conversion, application of carbon paste and silver paste, lamination, connection of cathode lead terminals, sealing with an epoxy resin, and aging operation were carried out in the same manner as in Example 1 to complete a total of 30 capacitors. Table 1 shows the results of the characteristic evaluation performed on the obtained multilayer capacitor element in the same manner as in Example 1.

Comparative Example 2:
In FIG. 1, an aluminum conversion foil having x of 30 μm, y / z = 1.5, a complementary angle of the cutting angle α (see FIG. 1) of 110 °, and an overall thickness (H) of 110 μm was used. An enlarged photograph of the cross-sectional shape is shown in FIG. A solid electrolyte was formed in the same manner as in Example 1 except that this aluminum conversion foil was used.
The film thickness of the corner portion (cut portion with a ridge side internal angle of 110 °) measured in the same manner as in Example 1 was 1 μm.

  Next, re-chemical conversion, application of carbon paste and silver paste, lamination, connection of cathode lead terminals, sealing with an epoxy resin, and aging operation were carried out in the same manner as in Example 1 to complete a total of 30 capacitors. Table 1 shows the results of the characteristic evaluation performed on the obtained multilayer capacitor element in the same manner as in Example 1.

Sectional drawing of an anode base | substrate. Sectional drawing which shows an example of the solid electrolytic capacitor using a capacitor | condenser element. Sectional drawing which shows an example of the solid electrolytic capacitor obtained by laminating | stacking a capacitor | condenser element. The side surface cross-section photograph (200 times) of the aluminum conversion foil used in Example 1. The side surface cross-section photograph (500 times) of the aluminum conversion foil used in Example 2. The side surface cross-section photograph (200 times) of the aluminum conversion foil used in Example 3. The side surface cross-section photograph (500 times) of the aluminum conversion foil used in Example 4. The side surface cross-section photograph (500 times) of the aluminum conversion foil used in Comparative Example 1. The side surface cross-section photograph (200 times) of the aluminum conversion foil used in Comparative Example 2. The side surface photograph (500 times) of the aluminum conversion foil used in Example 1. FIG.

Explanation of symbols

1 Anode Base 2 Dielectric (Oxide Film) Layer 3 Masking 4 Semiconductor (Solid Electrolyte) Layer 5 Conductor Layers 6 and 7 Lead Wire 8 Sealing Resin 9 Solid Electrolytic Capacitor

Claims (20)

  An anode substrate obtained by obliquely cutting a metal substrate including a valve metal layer having micropores and a valve metal layer having no micropores, and the valve metal layer having no micropores is stretched following the cutting blade. An anode substrate for a solid electrolytic capacitor, characterized by having a cut surface. An anode substrate obtained by obliquely cutting a metal substrate including a valve metal layer having micropores and a valve metal layer having no micropores, and the valve metal layer having no micropores is stretched to follow the cutting blade and is fine The extended valve metal layer formed by covering the end surface of the valve metal layer having holes has the following conditional expression:

Where y represents the thickness of the valve metal stretched layer in the substrate thickness direction, and z represents the thickness of the valve metal layer having micropores in contact with the stretched layer in the substrate thickness direction. The anode substrate for a solid electrolytic capacitor according to claim 1.   The anode substrate is in the form of a flat plate or a foil, and is obtained by cutting at an angle in the range of the ridge side between the anode substrate surface on the cutting start side and the cut surface within a range of more than 90 ° and not more than 135 °. The anode substrate for a solid electrolytic capacitor according to claim 2.   3. The anode substrate for a solid electrolytic capacitor according to claim 2, wherein the anode substrate is in the form of a flat plate or a foil, and the valve metal stretched layer is obtained by cutting and removing a portion protruding from the surface of the anode substrate.   3. The anode substrate for a solid electrolytic capacitor according to claim 2, wherein the anode substrate is in the form of a flat plate or a foil, and the valve metal stretched layer is obtained by chamfering a ridge including a portion protruding from the surface of the anode substrate.   3. The solid electrolysis according to claim 2, wherein the anode substrate has a flat plate shape or a foil shape, and the valve metal stretched layer is obtained by eliminating the protrusion by pressing the shaping member against a ridge including a portion protruding from the surface of the anode substrate. Anode base for capacitors.   An anode substrate obtained by obliquely cutting a metal substrate including a valve metal layer having micropores and a valve metal layer having no micropores, and the valve metal layer having no micropores is stretched following the cutting blade. The anode substrate for a solid electrolytic capacitor according to claim 2, comprising a groove that is oblique or parallel to the minor axis direction of the cut surface.   The anode substrate for a solid electrolytic capacitor according to claim 7, wherein the width of the oblique or parallel groove is 0.1 to 100 μm.   The anode substrate for a solid electrolytic capacitor according to claim 7, wherein the pitch of the oblique or parallel grooves is 0.1 to 100 μm.   The anode substrate for a solid electrolytic capacitor according to claim 7, wherein the depth of the oblique or parallel groove is 0.1 to 10 μm.   The anode substrate for a solid electrolytic capacitor according to claim 1, wherein the anode substrate is aluminum.   12. The anode substrate for a solid electrolytic capacitor according to claim 11, wherein the anode substrate is produced by cutting an aluminum conversion foil having fine holes into a strip shape by a cutting machine.   A solid electrolytic capacitor comprising the anode substrate for a solid electrolytic capacitor according to claim 1.   In the manufacturing method of the solid electrolytic capacitor which provided the solid electrolyte layer containing a conductive polymer composition by polymerizing a monomer with an oxidizing agent on the dielectric film formed on the valve action metal surface which has a fine hole, Claim 1 A method comprising the step of drying after immersion in a solution containing a monomer (step 1) and the step of drying after immersion in a solution containing an oxidizing agent (step 2) using the anode substrate for a solid electrolytic capacitor according to any one of -12 The method for producing a solid electrolytic capacitor according to claim 13, wherein a solid electrolyte layer is provided on a valve metal having a dielectric film layer.   Valve action metal having a dielectric coating layer by a method of repeating step 1 of immersing a valve action metal having a dielectric coating layer in a solution containing a monomer compound and drying, and step 2 of immersing and drying in a solution containing an oxidant a plurality of times The method for producing a solid electrolytic capacitor according to claim 14, wherein a solid electrolyte layer is provided on the solid electrolytic capacitor.   The method for producing a solid electrolytic capacitor according to claim 14 or 15, wherein the oxidizing agent is persulfate.   The method for producing a solid electrolytic capacitor according to claim 14, wherein the solution containing the oxidizing agent is a suspension containing organic fine particles. The method for producing a solid electrolytic capacitor according to claim 17, wherein the average particle diameter (D ₅₀ ) of the organic fine particles is in the range of 1 to 20 μm.   The organic fine particles are at least one selected from the group consisting of an aliphatic sulfonic acid compound, an aromatic sulfonic acid compound, an aliphatic carboxylic acid compound, an aromatic carboxylic acid compound, a salt thereof, and a peptide compound. Manufacturing method for solid electrolytic capacitor. A solid electrolytic capacitor manufactured by the manufacturing method according to claim 14.

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