JP2006332631A - 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: The solid-state electrolytic capacitor is characterized in that it includes an anode substrate in which at least one part of a edge side is chamfered, and the solid-state electrolytic capacitor especially has the anode substrate which is a plane or a foil and the edge side between the top face and/or bottom face of the anode substrate and the side face and/or end face is chamfered for at least a region to be provided with a solid-state electrolytic layer. The manufacturing method manufactures it. <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. 9, a basic element of a solid electrolytic capacitor is 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 etched, and on the outside thereof. 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, 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 formed a solid electrolyte layer by polymerizing a monomer with an oxidant on a subsequent dielectric film by using an anode substrate with chamfered at least a part of the edge. In the process, the inventors found that the formation of the polymer film on the corner portion and the side portion of the valve action metal proceeds uniformly. That is, the present inventors have found that when the angle of the corner portion of the anode substrate is more than 90 °, the formation of the polymer film on the corner portion proceeds uniformly.

  Further, the chamfered anode base body has a structure including a groove obliquely or parallel to the minor axis direction of the cut surface formed by extending the valve metal layer having no fine holes following the cutting blade. Thus, it has been found that there is an effect of facilitating the liquid absorption to the surface of the part having no ability to hold the solution and making the formation of the polymer film easy and uniform.

  It was confirmed that the solid electrolytic capacitor thus obtained improved the adhesion of the solid electrolyte formed on the dielectric film, has a high capacity, and has a low dielectric loss (tan δ), leakage current, and defective rate. Furthermore, it was confirmed that the capacitor can be made smaller and higher in capacity by laminating a plurality of solid electrolytic capacitor elements having excellent characteristics.

That is, this invention relates to the manufacturing method of the solid electrolytic capacitor shown below, the anode base | substrate for solid electrolytic capacitors, and a solid electrolytic capacitor.
That is, the present invention provides a solid electrolytic capacitor including an anode base having a chamfered at least part of the ridge shown below, a solid electrolytic capacitor anode base used for the solid electrolytic capacitor, and the solid electrolytic capacitor A method for producing a solid electrolytic capacitor in which a dielectric film and a solid electrolyte layer are provided on an anode substrate, or a solid electrolyte layer is provided on an anode substrate for a solid electrolytic capacitor in which a dielectric film is previously provided. The present invention relates to a solid electrolytic capacitor.
1. A solid electrolytic capacitor comprising an anode substrate having at least part of a ridge side chamfered.
2. 2. The anode substrate according to 1 above, wherein the anode substrate is flat or foil-shaped, and at least a region where the solid electrolyte layer is provided has a chamfered edge between the upper surface and / or the lower surface and the side surface and / or the end surface of the anode substrate. Solid electrolytic capacitor.
3. 3. The solid electrolytic capacitor as described in 2 above, wherein an angle of a corner portion between the upper surface and / or the lower surface and the side surface and / or the end surface of the anode substrate at the chamfered portion is more than 90 ° and less than 180 °.
4). 4. The solid electrolytic capacitor as described in 3 above, wherein the cross-sectional shape in the thickness direction of the side surface and / or the end surface of the anode substrate is a wedge shape having a tip angle of 90 ° or more and less than 180 °.
5. 5. The solid electrolytic capacitor as described in any one of 1 to 4 above, wherein the width and / or length of the upper surface and the lower surface of the anode substrate after chamfering are different.
6). The cross-sectional shape in the thickness direction of the side surface and / or the end surface of the anode substrate after chamfering is a convex polygon that is equal to or greater than a triangle, and each internal angle of the corner portion constituting the cross-sectional shape is more than 90 ° and less than 180 °. The solid electrolytic capacitor in any one of 1-5.
7). The anode substrate has grooves that are oblique or parallel to the minor axis direction of the cutting surface formed by stretching the valve metal layer that does not have micropores included in the chamfered anode substrate following the cutting blade. 2. The solid electrolytic capacitor as described in 1 above, which is an anode substrate.
8). 8. The solid electrolytic capacitor as described in 7 above, wherein the width of the oblique or parallel groove contained in the anode substrate is 0.1 to 100 μm.
9. 8. The solid electrolytic capacitor as described in 7 above, wherein the pitch of the oblique or parallel grooves contained in the anode substrate is 0.1 to 100 μm.
10. 8. The solid electrolytic capacitor as described in 7 above, wherein the depth of the oblique or parallel groove contained in the anode substrate is 0.1 to 10 μm.
11. 11. The solid electrolytic capacitor as described in any one of 1 to 10 above, wherein the anode base is a valve metal.
12 A solid electrolytic capacitor anode substrate, wherein the solid electrolytic capacitor is used for the solid electrolytic capacitor according to any one of 1 to 11 above.
13. 13. The anode substrate for a solid electrolytic capacitor as described in 12 above, wherein a chamfer is applied to the ridge side of the anode substrate obliquely to chamfer.
14 A slitter is obliquely applied to the anode base plate to form an intermediate product of the anode base in which the angle inside the ridge between the upper surface and the cut surface exceeds 90 °, and then on the ridge on the lower surface side of the intermediate product. The solid as described in 12 above, wherein the upper and lower ridges are chamfered by cutting so that an angle inside the ridge between the slitter cutting surface and the slitter cutting surface exceeds 90 °. Anode substrate for electrolytic capacitors.
15. A slitter is obliquely applied to the anode base plate to form an intermediate product of the anode base in which the angle inside the ridge between the lower surface and the cut surface exceeds 90 °, and then on the ridge on the upper surface side of the intermediate product. The solid as described in 12 above, wherein the upper and lower ridges are chamfered by cutting so that an angle inside the ridge between the slitter cutting surface and the slitter cutting surface exceeds 90 °. Anode substrate for electrolytic capacitors.
16. Thick blades of one disk-shaped blade unit and other disk-shaped blade units by alternately arranging a plurality of disk-shaped blade units composed of two blades, a thick blade and a thin blade, with a minute gap therebetween In a direction inclined by 1 to 15 degrees with respect to the cutting direction of the blade by passing the original plate of the anode base between the staggered disk-shaped blade units, using a slitter capable of cutting between the thin blades 13. The anode base for a solid electrolytic capacitor as described in 12 above, wherein the gap is cut so as to be discharged.
17. The anode substrate for a solid electrolytic capacitor as described in 12 above, wherein the side surface of the cut anode substrate is pressed against the surface of the abrasive present on the surface of the elastic support substrate that rotates.
18. 18. A method for producing a solid electrolytic capacitor, comprising: providing a dielectric film and a solid electrolyte layer on the anode substrate for a solid electrolytic capacitor according to any one of 12 to 17 above.
19. 18. A method for producing a solid electrolytic capacitor, wherein a solid electrolyte layer is provided on the anode substrate for a solid electrolytic capacitor provided with a dielectric film in advance in any one of 12 to 17 above.
20. A solid electrolyte layer is provided on a valve metal having a dielectric film layer by 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 oxidant (step 2). 20. The method for producing a solid electrolytic capacitor as described in 18 or 19 above.
21. 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 21. The method for producing a solid electrolytic capacitor as described in 20 above, wherein a solid electrolyte layer is provided on the solid electrolytic layer.
22. 22. The method for producing a solid electrolytic capacitor as described in 20 or 21 above, wherein the oxidizing agent is persulfate.
23. 22. The method for producing a solid electrolytic capacitor as described in 20 or 21 above, wherein the solution containing the oxidizing agent is a suspension containing organic fine particles.
24. 24. The method for producing a solid electrolytic capacitor as described in 23 above, wherein the organic fine particles have an average particle diameter (D ₅₀ ) in the range of 0.1 to 20 μm.
25. 23 or 24, wherein 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. The manufacturing method of the solid electrolytic capacitor of description.
26. A solid electrolytic capacitor produced by the production method according to any one of 18 to 25 above.

  According to the present invention, it is possible to stably produce a thin capacitor element with few short-circuit defects, little variation in element shape, and it is possible to increase the number of capacitor elements in a solid electrolytic capacitor chip to increase the capacity. Therefore, it is possible to provide a solid electrolytic capacitor element suitable for a multilayer solid electrolytic capacitor having a small variation in equivalent series resistance.

Hereinafter, the method of the present invention will be described with reference to the accompanying drawings.
In the present invention, the anode substrate used for the solid electrolytic capacitor does not have a corner portion that is 90 ° or less in the cross-sectional shape in the thickness direction, or a corner portion region that is 90 ° or less is reduced. That is, as shown by a broken line in FIG. 1, in the conventional anode base for a solid electrolytic capacitor, the corner portion of the cross-sectional shape in the thickness direction is substantially a right angle, but in the present invention, as shown by the solid line in FIG. The shape is chamfered along the side. As a result, the angle of the corner portion a or b of the anode substrate is more than 90 ° and less than 180 °. In the present specification and the appended claims, the “chamfered anode substrate” only needs to have a shape that can be obtained by performing the “chamfering” operation, and the actual “chamfering” operation is performed. It includes not only the obtained “anode substrate” but also an anode substrate that realizes such a shape after “chamfering” by some forming method.

The chamfering may be performed on all edges of the anode substrate, but may be performed only on the corner portion (A1 in FIG. 1) between the upper surface and the side surface (end surface), and between the lower surface and the side surface (end surface). May be performed only for the corner portion (A2 in FIG. 1). Further, it may be performed only for the corner portion between the upper and lower surfaces and the side surface of the anode substrate, or may be performed only for the corner portion between the upper and lower surfaces and the end surface of the anode substrate. Moreover, you may carry out only about some of these parts. Here, the “side surface” is a surface along the long side of the anode substrate (the side perpendicular to the liquid surface in the solid electrolytic capacitor manufacturing process described later), and the “end surface” is the short side of the anode substrate ( It is a surface along the side that is horizontally immersed in the liquid surface during immersion in the manufacturing process of the solid electrolytic capacitor described later.
Preferably, the ridges are chamfered over the entire region where the solid electrolyte layer is formed.

There are various cross-sectional shapes realized by chamfering in the present invention. Typically, chamfering is performed so that the cross-sectional shape in the thickness direction of the anode substrate becomes a wedge shape, and the angle of one corner portion of the three corner portions constituting the wedge shape is 90 ° or more and less than 180 °. And an anode substrate in which the angle of the other two corner portions is more than 90 ° and less than 180 °. Further, for example, chamfering can be performed so that the cross-sectional shape in the thickness direction is a triangle abc as shown in FIG. 1, but the cross-sectional shape in the thickness direction is trapezoidal abP (p1, p2) as shown in FIG. You may chamfer so that it is. In this case, the surface P may be the one that has left the side surface (or end surface) before chamfering, or the surface P that is once chamfered into a triangle abc as shown in FIG.
Further, in the case of a triangular abc shape (FIG. 3; excluding the hatched portion in FIG. 1), the angle c of the tip end portion c is preferably 90 ° or more and less than 180 °, more preferably more than 90 ° and less than 180 °. 2 and 3, the angles a and b may be different or the same. It is preferable that the angle “a” and the angle “b” of the corner portion constituting the wedge shape are more than 90 ° and less than 180 °. Furthermore, it is preferable that the angle a and the angle b of the corner portion constituting the wedge shape are more than 90 ° and less than 180 °, and the angle c is 90 ° or more and less than 180 °.

  1 to 3, a perpendicular line perpendicular to the lower surface from the apex of the corner portion a on the upper surface may intersect the corner portion b of the lower surface, but it is lowered perpendicularly to the lower surface from the apex of the corner portion a on the upper surface. A case where the perpendicular does not intersect with the corner portion d on the lower surface (x> 0 in FIG. 4) is also included in the present invention. Further, the present invention also includes the case where y> 0 (FIG. 5) where a perpendicular line perpendicular to the lower surface from the apex of the upper corner portion a does not intersect the corner portion f. The cross-sectional shape thus formed includes a convex polygon that is a triangle or more, and each angle of the corner portion constituting the cross-sectional shape is preferably 90 ° or more and less than 180 ° (provided that the convex polygon is a quadrangle). (Except when the corners are all 90 °).

In the case of FIG. 4, when the cut surface portion subjected to the chamfering process shown in the figure is a “side surface” in the above sense, the width of the lower surface of the anode base is longer by x on one side than the width of the upper surface (not shown). The same chamfering may be performed on the other non-side surface, in which case the bottom surface is 2x longer in total than the top surface). When the portion shown in FIG. 4 is an “end face” in the above sense, the length of the lower surface of the anode substrate is longer than the length of the upper surface by x. In the case of FIG. 4, the angles a and e of the corners constituting the wedge shape are more than 90 ° and less than 180 °, the angle d is 90 ° and less than 180 °, and x> 0. Is preferred.
In the case of FIG. 5, when the illustrated portion is a “side surface” in the above sense, the width of the lower surface of the anode base is shorter by y on one side than the width of the upper surface (the same chamfer is also applied to the other side surface not shown). In this case, the width of the lower surface is shorter than the width of the upper surface by a total of 2y). 5 is an “end face” in the above sense, the length of the lower surface of the anode base is shorter by y than the length of the upper surface. In the case of FIG. 5, the angles a and f of the corners constituting the wedge shape are more than 90 ° and less than 180 °, the angle g is 90 ° to less than 180 °, and y> 0. Is preferred.

In addition, as shown in FIG. 2, the corner c in FIG. 1 is further chamfered, and any one of the corners a, b, c, d, e, f, and g may be further chamfered. It is also possible to chamfer the corners. However, since the anode substrate is usually several tens to several hundreds of μm thick, the shapes of FIGS. 1 to 5 are realistic.
Further, the form of chamfering may be different or the same for each edge.

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 anode base as described above can be manufactured, for example, by chamfering the ridge side of the anode base with an oblique cutter. The upper and lower ridges may be chamfered simultaneously by pressing the cutter simultaneously from above and below the anode substrate.

  In addition, with respect to the side surface, a slitter is obliquely applied to the anode substrate base plate to form an anode substrate intermediate product in which the angle inside the ridge between the upper surface and the cut surface exceeds 90 °. A chamfered shape may be realized by obliquely applying a cutter to the ridge on the lower surface side and cutting so that the angle inside the ridge side between the slitter cutting surface exceeds 90 °, and vice versa. Or chamfering the upper surface side after cutting with a slitter from the side). In addition, by arranging a plurality of disk-shaped blade units composed of two blades, a thick blade and a thin blade, with a small gap in between, the thick blade of one disk-shaped blade unit and another disk-shaped blade unit Using a slitter capable of cutting between thin blades of the blade unit, the anode base plate is passed between the staggered disk-shaped blade units and inclined by 1 to 15 degrees with respect to the cutting direction of the blade. The gap may be adjusted and cut so as to be discharged in the direction.

On the other hand, the anode substrate having a wedge shape according to the present invention can be manufactured by polishing a side surface once cut in a ribbon shape or a hoop shape wound up by a certain amount. More specifically, it can be manufactured by chamfering by pressing the side surface of the cut chemical foil against the abrasive present on the surface of the elastic support substrate. An anode substrate having a valve metal layer that does not have micropores sandwiched between porous and metal valves having micropores is more fragile than a valve metal layer that has micropores. It has been found that the valve metal layer having fine pores can be selectively polished when pressed against an abrasive because it is low, and the wedge-shaped side surface of the present invention can be formed. For chamfering, it is more preferable to use an abrasive that exists on the surface of a support substrate having elasticity. That is, when an elastic support substrate is used, the valve metal layer having micropores existing on both sides of the valve metal layer that does not have higher-strength microholes at the apex is preferred. And polished. When the side surface of the cut chemical conversion foil is pressed against the abrasive present on the surface of the non-elastic support substrate, the valve metal layer having no fine holes is stretched, which is not preferable.
Among these, when polishing the anode substrate wound in a hoop shape, the abrasive used is preferably No. 120 to No. 2400, more preferably No. 320 to No. 500. Polishing can be produced by polishing using an abrasive present in a rotating substrate such as a grinder with a single action and a double action, but polishing by a double action is more preferable. Polishing by double action is particularly preferable because the valve metal layer having no micropores can be uniformly polished without being stretched even if the whole is cut to eliminate the part where the hoop material is unwound. .

  For the formation of the groove on the surface of the valve metal layer having no fine holes, it is efficient and preferable to perform the method simultaneously with the polishing of the side surface portion. However, when a desired groove is not formed by polishing the side surface portion, it is possible to perform polishing for groove processing separately. In particular, in order to shorten the time required for polishing, it may be more efficient to perform the processing separately from the groove processing on the polishing surface. More specifically, when the hoop material has a large winding deviation and requires a large amount of grinding, a method of separately polishing for grooving is preferably selected.

The substrate used in the present invention has a dielectric film on the surface. This is usually formed by chemical conversion treatment of a metal porous molded body having a valve action.
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. Further, the porous form may be any form as long as it is a form of a porous molded body such as an etching 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 can be used, and preferably a flat plate or a foil.
Furthermore, a known method can be used as a method of forming a dielectric oxide film on the surface of the porous metal body. 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.

  For example, the thickness of the valve action metal foil varies depending on the purpose of use, but 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.

  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. In general, masking (3) is provided (see FIG. 9).

  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.
The first treatment step of immersing in the solution containing the monomer and drying in the present invention is performed to supply the monomer on the dielectric surface and on 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 the first treatment step 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, it is 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 the first treatment step 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); esters such as ethyl acetate and butyl acetate; non-aromatic chlorine solvents such as chloroform and methylene chloride; nitro compounds such as nitromethane, nitroethane, and nitrobenzene Alcohols such as methanol, 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 the immersion in the oxidant-containing liquid and the second treatment step held in the air for a predetermined time in a certain temperature range, but in order to make the form of the polymerized film more precise, A method mainly using oxidative polymerization held in air is preferred. 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 immersion time applied as the second treatment step is a time sufficient for the oxidant component to adhere on 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.

Examples of the oxidizing agent used in the second treatment step 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 the second treatment step 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 and N-methyl. Aprotic polar solvents such as pyrrolidinone (NMP) and dimethyl sulfoxide (DMSO); alcohols such as methanol, ethanol and 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 the second treatment step, 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 of the first treatment step and the second treatment step 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. In addition, you may perform a 1st process process and a 2nd process process 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. 10, 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 (4) 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. A capacitor (9) product.

  The present invention will be described in more detail below with typical examples. Note that these are merely illustrative examples, and the present invention is not limited thereto. In addition, the aluminum chemical conversion foil used in the following experiment is a single disk by arranging a plurality of disk-shaped blade units formed by combining two blades, a thick blade and a thin blade, with a minute gap therebetween. Using a slitter that can cut between the thick blade of the blade-shaped blade unit and the thin blade of the other disk-shaped blade unit, the anode base plate is passed between the staggered disk-shaped blade units and the blade The gap was adjusted and cut so as to be discharged in a direction inclined by 1 to 15 degrees with respect to the cutting direction.

Example 1:
An aluminum formed foil having a wedge shape conforming to FIG. 3 and having an angle a of 165 degrees, an angle b of 120 degrees, and an angle c of 90 degrees in a cross-sectional shape in the thickness direction (thickness: 100 μm) It was used. This chemical conversion foil was prepared by adjusting the gap so that the discharge angle was 5 degrees with the slitter. 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, this immersion process and polymerization process were performed 20 times in total, and a solid electrolyte layer of a conductive polymer was formed on the outer surface of the aluminum foil. 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 solid electrolyte layer at the corner portion by microscopic observation of the cross-sectional shape was uniform at 17 μm at the corner a portion, 15 μm at the corner b portion, and 15 μm at the corner c portion.

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. 10, 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:
An aluminum conversion foil (thickness: 100 μm) having a wedge-shaped cross-sectional shape in the thickness direction and having three corners at an angle a of 175 °, an angle b of 120 °, and an angle c of 90 ° was used. An enlarged photograph of the cross-sectional shape is shown in FIG. This chemical conversion foil was prepared by adjusting the gap in the previous period so that the discharge angle was 7 degrees with the slitter. 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 solid electrolyte layer at the corner portion by microscopic observation of the cross-sectional shape was uniform at 15 μm at the corner a portion, 12 μm at the corner b portion, and 12 μm at the corner c portion.

  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:
An aluminum conversion foil (thickness: 100 μm) having a wedge-shaped cross-sectional shape in the thickness direction and having three corners at an angle a of 105 °, an angle b of 135 °, and an angle c of 105 ° was used. An enlarged photograph of the cross-sectional shape is shown in FIG. This aluminum chemical conversion foil was manufactured by polishing for 15 minutes with a double action type grinder in which a No. 500 abrasive was attached to the surface of a urethane resin support. 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 solid electrolyte layer at the corner portion by microscopic observation of the cross-sectional shape was uniform at 16 μm at the corner a portion, 14 μm at the corner b portion, and 16 μm at the corner c portion.

  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:
An aluminum chemical composition having a wedge shape according to FIG. 2 and having four corners in which the angle a is 105 °, the angle b is 105 °, the angle p1 is 165 °, and the angle p2 is 165 °. A foil (thickness 100 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 chemical conversion foil is polished for 15 minutes by a double action type grinder having a No. 320 abrasive pasted on the surface of a urethane resin support, and then water resistant abrasive paper No. 500 at 45 ° to the minor axis direction. It was manufactured by polishing in an oblique direction for 2 minutes. A solid electrolyte was formed in the same manner as in Example 1 except that this aluminum conversion foil was used.
The thickness of the solid electrolyte layer at the corner portion by microscopic observation of the cross-sectional shape was uniform at 15 μm at the corner a portion, 14 μm at the corner b portion, 15 μm at the corner p1 portion, and 16 μm at the corner p2 portion.

  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:
An aluminum conversion foil (thickness: 100 μm) in which the angles of the two corners in the cross-sectional shape in the thickness direction, which is a sword shape, are 70 degrees and 110 degrees, respectively. 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 solid electrolyte layer at the corner portion by microscopic observation of the cross-sectional shape was 3 μm and 15 μm, and the polymer film at the acute corner portion (corner portion having an angle of 70 degrees) was thin. Next, 30 capacitors were completed in the same manner as in Example 1, and the results of the characteristic evaluation performed on the obtained multilayer capacitor element in the same manner as in Example 1 are shown in Table 1.

The fragmentary sectional view which shows the structure (solid line) of the anode base | substrate for solid electrolytic capacitors by one embodiment of this invention in contrast with a prior art example (broken line). The fragmentary sectional view which shows the structure (solid line) of the anode base | substrate for solid electrolytic capacitors by another embodiment of this invention in contrast with a prior art example (broken line). 1 is a partial cross-sectional view showing a structure of an anode substrate for a solid electrolytic capacitor according to an embodiment of the present invention. The fragmentary sectional view which shows the structure of the anode base | substrate for solid electrolytic capacitors by another embodiment of this invention. The fragmentary sectional view which shows the structure of the anode base | substrate for solid electrolytic capacitors by another embodiment of this invention. A cross-sectional photograph in the thickness direction of the aluminum conversion foil (anode substrate) used in Example 1 (500 times; in the figure, the light-colored portion is the unformed portion of the aluminum foil, and the dark-colored portion is the formed portion) . A cross-sectional photograph in the thickness direction of the aluminum conversion foil (anode substrate) used in Example 2 (500 times; in the figure, the light-colored portion is the unformed portion of the aluminum foil, and the dark-colored portion is the formed portion) . A cross-sectional photograph in the thickness direction of the aluminum conversion foil (anode substrate) used in Comparative Example 1 (500 times; in the figure, the light-colored portion is the unformed portion of the aluminum foil, and the dark-colored portion is the formed portion) . 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. A cross-sectional photograph (500 times larger) of the aluminum conversion foil (anode substrate) used in Example 3 (in the figure, the light-colored portion is a valve metal layer having no porosity, and the dark-colored portion is a porous layer portion) is there). Cross-sectional photograph of the aluminum conversion foil (anode substrate) used in Example 4 in the thickness direction (500 times; in the figure, the light-colored portion is a valve metal layer having no porosity, and the dark-colored portion is a porous layer portion. is there). A cut surface photograph of the aluminum conversion foil (anode substrate) used in Example 1 (500 times; in the drawing, a light-colored portion is a valve metal layer having no porosity, and a dark-colored portion is a porous layer portion). A cut surface photograph of the aluminum conversion foil (anode substrate) used in Example 4 (500 times; in the drawing, the light-colored portion is a valve metal layer having no porosity, and the dark-colored portion is a porous layer portion).

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 (26)

  A solid electrolytic capacitor comprising an anode substrate having at least part of a ridge side chamfered.   2. The ridge side between the upper surface and / or the lower surface and the side surface and / or the end surface of the anode substrate is chamfered at least in a region in which the anode substrate is flat or foil-shaped and at least the solid electrolyte layer is provided. Solid electrolytic capacitor.   3. The solid electrolytic capacitor according to claim 2, wherein an angle of a corner portion between the upper surface and / or the lower surface and the side surface and / or the end surface of the anode substrate at the chamfered portion is more than 90 ° and less than 180 °.   4. The solid electrolytic capacitor according to claim 3, wherein a cross-sectional shape in a thickness direction of the side surface and / or the end surface of the anode substrate is a wedge type whose tip angle is 90 ° or more and less than 180 °.   The solid electrolytic capacitor according to claim 1, wherein the width and / or length of the upper surface and the lower surface of the anode substrate after chamfering are different.   The cross-sectional shape in the thickness direction of the side surface and / or the end surface of the anode substrate after chamfering is a convex polygon that is a triangle or more, and each internal angle of the corner portion constituting the cross-sectional shape is more than 90 ° and less than 180 ° Item 6. The solid electrolytic capacitor according to any one of Items 1 to 5.   The anode substrate has grooves that are oblique or parallel to the minor axis direction of the cutting surface formed by stretching the valve metal layer that does not have micropores included in the chamfered anode substrate following the cutting blade. The solid electrolytic capacitor according to claim 1, wherein the solid electrolytic capacitor is an anode substrate.   The solid electrolytic capacitor according to claim 7, wherein a width of an oblique or parallel groove included in the anode substrate is 0.1 to 100 μm.   The solid electrolytic capacitor according to claim 7, wherein the pitch of the oblique or parallel grooves included in the anode substrate is 0.1 to 100 μm.   The solid electrolytic capacitor according to claim 7, wherein the depth of the oblique or parallel groove included in the anode substrate is 0.1 to 10 μm.   The solid electrolytic capacitor according to claim 1, wherein the anode base is a valve metal.   An anode substrate for a solid electrolytic capacitor, which is used in the solid electrolytic capacitor according to claim 1, wherein at least a part of a ridge side is chamfered.   The anode substrate for a solid electrolytic capacitor according to claim 12, wherein the anode substrate is chamfered obliquely on a ridge side of the anode substrate.   A slitter is obliquely applied to the anode base plate to form an intermediate product of the anode base in which the angle inside the ridge between the upper surface and the cut surface exceeds 90 °, and then on the ridge on the lower surface side of the intermediate product. The shape according to claim 12, wherein the upper and lower ridges are chamfered by cutting so that an angle inside the ridge between the slitter cutting surface and the slitter cutting surface exceeds 90 °. Anode substrate for solid electrolytic capacitor.   A slitter is obliquely applied to the anode base plate to form an intermediate product of the anode base in which the angle inside the ridge between the lower surface and the cut surface exceeds 90 °, and then on the ridge on the upper surface side of the intermediate product. The shape according to claim 12, wherein the upper and lower ridges are chamfered by cutting so that an angle inside the ridge between the slitter cutting surface and the slitter cutting surface exceeds 90 °. Anode substrate for solid electrolytic capacitor.   Thick blades of one disk-shaped blade unit and other disk-shaped blade units by alternately arranging a plurality of disk-shaped blade units composed of two blades, a thick blade and a thin blade, with a minute gap therebetween In a direction inclined by 1 to 15 degrees with respect to the cutting direction of the blade by passing the original plate of the anode base between the staggered disk-shaped blade units, using a slitter capable of cutting between the thin blades The anode substrate for a solid electrolytic capacitor according to claim 12, wherein the gap is cut so as to be discharged.   13. The anode substrate for a solid electrolytic capacitor according to claim 12, wherein the chamfered surface is pressed by pressing the side surface of the cut anode substrate against the surface of the abrasive present on the surface of the rotating elastic support substrate.   A method for producing a solid electrolytic capacitor, comprising providing a dielectric film and a solid electrolyte layer on the anode substrate for a solid electrolytic capacitor according to any one of claims 12 to 17.   A method for producing a solid electrolytic capacitor, comprising providing a solid electrolyte layer on the anode substrate for a solid electrolytic capacitor, which is previously provided with a dielectric film according to any one of claims 12 to 17.   A solid electrolyte layer is provided on a valve metal having a dielectric film layer by 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 oxidant (step 2). The method for producing a solid electrolytic capacitor according to claim 18 or 19, wherein:   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 21. The method for producing a solid electrolytic capacitor according to claim 20, wherein a solid electrolyte layer is provided on the solid electrolytic layer.   The method for producing a solid electrolytic capacitor according to claim 20 or 21, wherein the oxidizing agent is persulfate.   The method for producing a solid electrolytic capacitor according to claim 20 or 21, 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 23, wherein an average particle diameter (D ₅₀ ) of the organic fine particles is in a range of 0.1 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. The manufacturing method of the solid electrolytic capacitor of description. The solid electrolytic capacitor manufactured with the manufacturing method in any one of Claims 18-25.

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