JP2000049054A - Electrolytic capacitor and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolytic capacitor of a large capacity fully close to a designed capacity, and a method for easier manufacturing. SOLUTION: This electrolytic capacitor has a conductive high polymer layer for a cathode or electrolytic electrodes 9a and 9b are formed on at least one side surface of an anode valve metal, at an anode valve metal foil which has a throughhole while having the surface roughened, and electrolysis is performed with the high polymer layer as an anode 2 in a conductive monomer solution, to form an electrolytic formation conductive high polymer layer 4 on the surface of a dielectrics oxide coat of the valve metal foil, thus providing an electrolytic capacitor. An electrolytic capacitor with a large capacity fully close to designed capacity is thus provided easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrolytic capacitor using a valve metal such as aluminum or tantalum as an anode and a conductive polymer layer as a cathode, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, an electrolytic capacitor using a valve metal such as aluminum or tantalum has a valve metal as an anode layer,
An oxide film of the valve metal was used as a dielectric layer, an electrolyte solution or an inorganic solid electrolyte was used for the cathode, and leads were respectively connected to the anode and the cathode.

[0003] The anode valve metal is used to form an oxide film.
The surface of the aluminum foil is roughened and anodized,
This is an aluminum anode element. In a tantalum capacitor, a compact made of powder is fired and the surface is anodized to obtain a tantalum anode element. As for the other cathode, a conventional aluminum electrolytic capacitor uses an organic solvent or the like containing an organic acid for the cathode, and a tantalum electrolytic capacitor uses manganese dioxide.

In recent years, high-frequency response of electronic components has been required in response to digitization of circuits, and therefore, improvement of high-frequency response by lowering resistance has also been required for electrolytic capacitors. In response to such demands from the market, use of a conductive polymer having high electric conductivity as a solid electrolyte for a cathode of an electrolytic capacitor has been studied and developed.

In an electrolytic capacitor using a conductive polymer as a solid electrolyte for a cathode, a dielectric of an oxide film on a valve metal is closely covered with a conductive polymer layer.
Electrolytic capacitors using such conductive polymers are:
For example, it is known from JP-A-6-168885.

[0006] To form a conductive polymer for the cathode, a chemical polymerization method is known. In this method, the anode element is immersed in a monomer solution containing an oxidizing agent, and the monomer is polymerized using the oxidizing agent as a polymerization initiator. As a result, a conductive polymer layer is formed on the oxide film on the anode surface.

[0007] An electrolytic oxidation polymerization method is also known. this is,
A first conductive layer for electrolysis having some conductivity is formed on the dielectric oxide film, and this conductive layer is used as a starting point of further polymerization to start oxidative polymerization electrolytically, and to have a required thickness. Then, a conductive polymer layer is formed. This first conductive layer is made of manganese dioxide previously deposited on the oxide film, or
Alternatively, an extremely thin conductive polymer layer formed by the chemical polymerization method has been used.

[0008]

However, the formation of the conductive polymer layer by the above-mentioned method has several problems. It is difficult to form the conductive polymer layer uniformly and sufficiently thick over the entire surface of the dielectric oxide film, and as a result, the capacity of the electrolytic capacitor in the final product is expected to be designed from the anodized valve metal. Not enough for the value. Furthermore, in order to increase the capacity, in the conventional technology, the polymerization reaction is slow, so that the above chemical polymerization method had to be repeated several to several tens of times.

In the conventional electrolytic polymerization method, since a conductive polymer layer formed extremely thin by manganese dioxide or chemical polymerization is used as the first conductive layer, the supply current for electrolysis has a relatively high electric resistance. Through the first conductive layer, for this,
A relatively long polymerization time was required to form a conductive polymer on the entire surface of the dielectric oxide film.

[0010] Conventionally, in order to electrolytically form a conductive polymer layer on the front and back of the anode foil, polymerization is first started from a part of one side of the anode foil and then turned to the opposite side. Had taken the method of proceeding. In this conventional method, when a conductive polymer layer is formed on the front and back of a relatively large area of the anode foil by electrolytic polymerization, a long time is required for the polymerization. Further, there was a difference in the thickness of the conductive polymer layer formed between the polymerization start point and the polymerization end point. This difference in the thickness of the conductive polymer layer results from the difference in the polymerization time between the polymerization start point and the polymerization end point. Therefore, in order to obtain a conductive polymer layer having a relatively uniform thickness,
In order to minimize the influence of the difference in polymerization time, it is necessary to further reduce the polymerization rate, which results in a longer polymerization formation step.

For the above reasons, for example, Japanese Patent Application Laid-Open
In fact, as in the example of JP-A-239917, this method was able to form a conductive layer only on a relatively small anode foil conforming to the shape of the final product. In any case, in order to form a necessary and sufficient conductive polymer layer as a final product, the manufacturing process becomes complicated and long, and a high manufacturing cost is required.

An object of the present invention is to provide an electrolytic capacitor in which a conductive polymer layer is uniformly and simply formed over the entire surface of a dielectric oxide film and has a large capacitance sufficiently close to a designed capacitance. Another object of the present invention is to provide a method for forming a conductive polymer layer uniformly and easily on an entire surface of a dielectric oxide film on an electrolytic capacitor.

The electrolytic capacitor of the present invention has a through-hole, a surface of which is roughened, a valve metal foil for an anode provided with a dielectric layer of an oxide film partially formed on the surface, and a conductive film on the oxide film layer. And a cathode layer of a conductive polymer, wherein the cathode layer includes an electroformed conductive polymer layer formed on the oxide film layer.

Further, the cathode layer may include a cathode conductive polymer layer formed on one side of the anode layer.
An electroformed conductive polymer layer formed on the dielectric layer is electrically connected to the conductive polymer layer for a cathode. Further, the electrolytic capacitor includes a current collector, and the current collector is preferably a metal sheet formed on the conductive polymer layer for the cathode on one side of the anode layer. The cathode current collector is used to be connected to the cathode lead.

The present invention relates to a valve metal foil for an anode having a through-hole, a roughened surface, a dielectric layer of an oxide film partially formed on the surface, and a conductive polymer on the oxide film layer. And a method for manufacturing an electrolytic capacitor including the above cathode layer. In this manufacturing method, an electropolymerization method is used to cause electrolysis between an electrode for electrolysis formed on a valve metal foil and a separate electrode in a monomer solution, and a conductive polymer obtained by electrolytic polymerization is applied to the valve metal foil. Formed on the surface of the electrolytic capacitor, and this is used for the cathode layer of the electrolytic capacitor.

More specifically, the manufacturing method includes forming an electrode for electrolysis on one surface of the valve metal foil for an anode, and immersing the valve metal foil for an anode in a conductive monomer liquid in which a separate electrode for electrolysis is arranged. Then, electrolysis is performed between the electrode for electrolysis on the metal foil and the electrode for electrolysis separately disposed in the liquid, and the monomer is electrolytically oxidized and polymerized to form an electroformed conductive polymer layer for the anode. It is formed as a cathode layer on the oxide film surface of the valve metal foil.

In the polymerization step, the positive electrode is brought into contact with the electrolysis electrode as a positive electrode on the valve metal foil while a current flows between the electrolysis electrode as a negative electrode in the solution and a separate electrolysis electrode. On the valve metal foil, the monomer is polymerized by electrolytic oxidation polymerization. Thereby, the conductive polymer layer is formed with a uniform thickness on the surface of the oxide film of the dielectric layer.

In the course of this electrolytic polymerization, polymerization of the monomer starts on the surface of the electrode for electrolysis, which is a positive electrode for electrolysis, and the polymer continues to grow, and a large number of through holes of the valve metal foil. , And further wrapped around the opposite side of the valve metal foil to cover the entire surface of the valve metal foil immersed in the solution to form an electroformed conductive polymer layer. The conductive polymer layer formed by electrolysis in this manner adheres to the dielectric layer of the oxide film of the metal foil.

The production method of the present invention comprises a metal sheet for electrolysis,
A conductive polymer layer or a combination thereof can be used. After the polymerization step, the electrode for electrolysis is removed, especially when it is a single metal sheet or metal foil. However, in the manufacturing method, the electrode for electrolysis may include a conductive polymer layer for electrolysis (hereinafter referred to as a cathode-side conductive polymer layer) formed in advance on the dielectric layer of the valve metal foil. Prior to the polymerization step, the cathode-side conductive polymer layer is formed in advance on the valve metal foil, and is left as it is after the polymerization step, and is used together with the electrolytically formed conductive polymer layer as the cathode layer of the capacitor. You.

Further, the electrode for electrolysis may be composed of a cathode-side conductive polymer layer on the valve metal foil and a metal sheet on the cathode-side conductive polymer layer. After the electrolytic polymerization, the cathode-side conductive polymer layer is used as a cathode layer, and the metal sheet is used as a cathode current collector.

In the electrolytic polymerization method of the present invention, any one of a metal foil, a conductive polymer layer for a cathode and a conductive polymer layer for a cathode provided on a metal foil for a cathode may be used as a starting point of the electrolytic polymerization by the electrode for electrolysis. Even in the case of selection, the conductivity can be increased, the electrolytic current can be increased, the formation speed of the conductive polymer layer is high, and the formation of the conductive polymer layer becomes easy. Furthermore, in the electrolytic polymerization method of the present invention, the growing polymer is formed all at once in the thickness direction of the anode valve metal foil through the through-hole of the metal foil. The surface of the metal foil immersed in the solution can be uniformly coated in a short time without being affected. Therefore, the conductive polymer layer can be formed in a short time and easily in this way, and it is possible to easily obtain an electrolytic capacitor capable of taking out a large capacity close to the designed capacity.

The production method of the present invention also includes, before the polymerization step, further forming a conductive layer in advance so that the entire surface or a part of the dielectric layer can be used as a cathode layer.
The conductive layer thus formed comes into contact with the growing polymer layer and serves as an anodic reaction start point for the polymerization of the monomer. Thus, the preformed conductive layer accelerates the polymerization rate in the growth direction of the electrolytic polymerization, enlarges the polymer region on the anode layer, and further increases the thickness. As the conductor layer on the dielectric layer, a conductive polymer layer can be used, and in particular, a chemically polymerized polymer may be used, and an oxide film such as manganese dioxide may be used. The presence of this conductor layer is useful for forming an electroformed conductive polymer layer by electrolytic polymerization. The dielectric layer can thus be completely covered by the electroformed conductive polymer layer.

The present invention further includes a laminated or wound electrolytic capacitor assembled from the above electrolytic capacitor. The laminate includes an anode lead connected to the valve metal and a cathode lead connected to the cathode-side conductive polymer layer or current collector. Since the plurality of electrolytic capacitor units are stacked and integrated with a sufficient capacity, a stacked electrolytic capacitor having a large capacity and a small size can be easily obtained. Further, in the wound-type electrolytic capacitor, since the electrolytic capacitor unit has a smaller size than the high capacity, a sufficiently large capacity can be obtained. By adjusting the length of the electrolytic capacitor unit, the capacity of the wound electrolytic capacitor can be freely adjusted.

In the method for manufacturing a multilayer electrolytic capacitor according to the present invention, several electrolytic capacitors are laminated.
After electrically connecting and integrating the metal surface portions of the anode valve metal foil, a step of re-anodizing a part of the anode valve metal foil other than the integrated metal surface portion is included. Thereafter, the conductive polymer layer for the cathode or the electrolytically formed conductive polymer layer is electrically connected.

According to this manufacturing method, it is possible to repair the partial damage of the dielectric layer of the oxide film due to the mechanical strain generated in the step of laminating and integrating the metal surface portions, and to obtain the obtained electrolytic capacitor. Is more reliable.

The method for producing a wound electrolytic capacitor of the present invention may include a step of re-anodizing a part of the anode valve metal foil of the wound electrolytic capacitor. Partial damage of the dielectric layer of the oxide film due to mechanical stress generated in the process of winding the electrolytic capacitor,
Repair becomes possible, and the obtained electrolytic capacitor becomes more reliable.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION In an electrolytic capacitor of the present invention, a valve metal foil 1 used for an anode layer 2 has a large number of fine through holes 20 on its surface as shown in FIG. The surface of the foil is roughened. The anode valve metal foil 1 has an oxide film layer formed by oxidizing the surface, and this is used as a very thin dielectric layer 3.

On the dielectric layer 3 of the oxide film, FIG.
Almost the entire surface of the dielectric layer 3 is formed by coating with an electroformed conductive polymer layer 4. The conductive polymer layer 4
It penetrates into many through holes and forms a dense conductive layer in close contact with the oxide film of the dielectric layer 3. In this electrolytic capacitor, an electrolytic capacitor is formed between the anode metal foil and the electroformed conductive polymer layer 4 with the oxide film dielectric layer 3 interposed therebetween. This electrolytically formed polymer layer is formed in a wide area on the dielectric layer 3 of the oxide film, functions as a cathode layer, and can sufficiently increase the capacity.

In the present invention, the metal 2 constituting the anode valve metal foil 1 forms a stable oxide film on the surface, and a material having a high insulating property and a high dielectric constant of the oxide film is used. , A valve metal such as aluminum, tantalum or niobium is used. The valve metal foil is more preferably aluminum for reasons such as cost and ease of processing.

A large number of through holes 20 formed in the anode valve metal foil 1 are for allowing the polymer to pass through and grow in the course of electrolytic polymerization. It is preferable that the thickness is not more than 1. The through hole reduces the area of the main surface of the valve metal foil. On the other hand, the through hole creates a new area on the side surface of the through hole. When comparing the area of the main surface of the valve metal foil, which is reduced by perforating the through-hole, with the area of the side surface of the through-hole generated by perforation, the above-mentioned condition, that is, the radius of the through-hole, has a valve action. If the thickness is equal to or less than the thickness of the metal foil, the area is not reduced by the through hole.

The density or occupied area on the surface of the through-hole is preferably 10% or less of the surface area of the metal foil. If too many through holes are formed, the mechanical strength of the valve metal foil for the anode is reduced, which causes inconvenience in manufacturing.

In the present invention, for the conductive polymer layer 5 for the cathode and the conductive polymer layer 4 formed by electrolysis, a polymer in which a polymer itself polymerized from a monomer exhibits conductivity is used. The polymer layers 4, 5 are preferably made of a five-membered heterocyclic compound such as pyrrole, thiophene, 3-alkyl for reasons of high conductivity, availability and chemical and physical stability. Polymers of thiophene and isothianaphthene monomers are used.

(Embodiment 1) In the present invention, such a conductive polymer layer 4 is formed by a method of electrolytically oxidatively polymerizing the above monomer. In this manufacturing method, an electrode 9a for electrolysis is previously formed or arranged on one side of a valve metal foil for an anode, and a current is made to flow through these electrodes as a positive electrode to be a starting point of an electrolytic polymerization reaction.

In this embodiment, an electrolysis metal sheet 90,
For example, a nickel sheet or foil is used as the electrode 9a for electrolysis.
Widely used for. However, other metals and inorganic materials can be used if they can be used as a positive electrode in a monomer solution without corrosion or passivation.

The electrode for electrolysis and the valve metal foil are connected to each other and immersed in a monomer solution. A current flows between the electrolysis electrode in contact with the valve metal and a separate electrolysis electrode arranged in the solution, and an electrolytic polymerization reaction occurs on the surface of the electrolysis electrode by anodic oxidation. When the electrolysis is continued, a polymerization reaction further occurs continuously at the interface of the produced polymer. The polymer reaches the surface of the metal foil, further fills the through hole or travels through the inside of the through hole, and exits to the other surface side of the metal foil, and is integrated and continuous in the thickness direction while covering the valve metal foil. And a dense and uniform polymer layer is formed on the entire surface of the metal foil.

As a result, a necessary and sufficient conductive polymer layer can be formed in a shorter time as compared with the conventional method, so that the manufacturing process can be simplified and the manufacturing cost can be reduced.

The electrolytic capacitor formed as described above includes:
The valve metal foil 2 and the electroformed conductive polymer layer 4 are connected to another conductive material, for example, a metal comb for anode extraction and cathode extraction, respectively. And

The method for manufacturing the electrolytic capacitor of the present invention will be described in more detail below. (A) First, a through hole 20 is formed in the valve metal foil for anode 1, and the foil surface is roughened. In this step, the through holes 20
Preferably, a large number are formed uniformly on the foil surface within an inner diameter range of about 0.05 to 0.5 mm. These through holes are for allowing the polymer to penetrate and grow in the course of electrolytic polymerization. As described above, the radius of the through hole is more preferably equal to or less than the thickness of the valve metal foil for an anode. Through hole 2
A large number of 0s are formed on a metal foil by a method of mechanical perforation or chemical etching using a punching machine or a drill, or a method combining these methods.

In order to roughen the surface of the valve metal foil for the anode, a method of mechanically roughening the surface such as an alternating current etching method, a direct current etching method, a sand blast method or the like in an electrolytic solution, and these methods Can be used.

(B) The surface of the anode valve metal foil is anodized to form an oxide film dielectric layer. In this step, in the case of an aluminum foil, the surface is subjected to anodizing treatment in an anodizing solution to form an aluminum oxide layer as the oxide film layer 3 on the aluminum foil surface. As a means for forming the oxide film layer, a conventional method such as constant voltage anodic oxidation or constant current anodic oxidation in an anodizing solution is used.

(C) Next, a metal surface portion is formed on a part of the surface of the anode valve metal foil. A part of the aluminum oxide layer on the surface of the aluminum foil is polished and peeled off or cut to expose metal aluminum as the metal surface portion 6.
In another exposure method, prior to the step (b) of forming a dielectric layer of an oxide film, a part of the metal surface of the metal foil for the anode is masked with a paint or an adhesive tape, and the masking is performed after the anodic oxidation. Except for, the metal surface can also be exposed.

(D) Next, an electrolysis electrode 9a is arranged on one side of the anode valve metal foil. In this step, a metal sheet 90 for electrolysis is used for the electrode 9a for electrolysis, and the valve metal foil is attached to the metal sheet 90 for electrolysis so that the oxide film layer 3 contacts. One example is an electrolytic metal sheet 90 (for example, nickel sheet 1) as an electrolytic electrode 9a for polymerization.
2) can be brought into contact with the oxide film dielectric layer 3 as shown in FIG.

(E) Next, an electroformed conductive polymer layer 4 is formed on the dielectric layer 3 of the valve metal foil by electrolytic polymerization. In this electrolytic polymerization step, as shown in FIG. 3 (B), the valve metal foil 2 carried on the electrode for electrolysis 9a (nickel sheet) in the previous step converts the monomer solution 1 into a conductive polymer.
1 (for example, a pyrrole solution), the electrolytic electrode 9a is used as a positive electrode, another electrode 9b disposed in the solution is used as a cathode, and the electrolytic treatment is performed. To form

Another electrode 9b is used for the electrolysis electrode 9a (nickel sheet) for electrolysis (a nickel sheet having the same area is preferably used). It is arranged on the opposite side of the electrode 9a (nickel sheet). Accordingly, when a current is caused to face the monomer solution 11 (for example, a pyrrole solution) filled in the container 10, it is important to arrange the current so that the current flows through the many through holes 20.

The polymer is adhered to the valve metal foil 1 by electrolytic polymerization while polymerizing the monomer in the solution starting from the electrolytic metal sheet 90 as the electrolytic electrode 9a.
Further, the polymer is grown (mainly in the direction of the arrow as shown in FIG. 4) so as to fill and pass through the through-hole 20. A current is applied for a certain period of time to form a polymer on the other side of the metal foil, and thus the conductive polymer layer 4 is formed by electrolytic formation. Next, the valve metal foil 1 is peeled from the nickel sheet 12 of the metal sheet 90 for electrolysis as the electrode 9a for electrolysis.

(F) Further, in the same manner as in the step (d), the electrode 9 for electrolysis is applied to the opposite surface of the peeled valve metal foil 1.
a, and then, in the same manner as in the above (e),
An electroformed conductive polymer layer 4 is formed on the dielectric layer 3 of an oxide film. When the electrode 9a for electrolysis is finally peeled off by the above steps, an electrolytic capacitor as shown in FIGS. 1A and 1B and FIGS. 2A and 2B is obtained.

According to the method of the present invention, starting from the electrode for electrolysis arranged on one side of the valve metal foil for anode, the electroformed conductive polymer layer is simultaneously formed mainly in the thickness direction of the valve metal foil for anode. It can be formed integrally and continuously. Therefore,
It becomes possible to form the conductive polymer layer in a shorter time and easily than in the conventional method, and the manufacturing process can be simplified,
Manufacturing costs can be reduced.

Prior to the electrolytic polymerization step, a conductive layer may be formed on the oxide film in advance, and then the electroformed conductive polymer layer 4 may be formed by an electrolytic oxidation polymerization method. As the conductive layer, manganese dioxide formed by thermal decomposition of manganese nitrate or a conductive polymer layer formed by a chemical polymerization method is preferable. In the step of electrolytic polymerization, the electrolytic polymerization is started from the above-mentioned electrode for electrolysis, and when the conductive polymer reaches and contacts the conductive layer on the oxide film, the conductive layer is used as a starting point of the polymerization, and a monomer is further formed. To form and grow a conductive polymer. Therefore, the electrolytically formed conductive polymer layer can cover the oxide film densely and promote the formation of the conductive polymer layer.

(Embodiment 2) In the electrolytic capacitor of this embodiment, as shown in FIG. 5, one side of the valve metal foil for anode 1 has a conductive layer for cathode on the dielectric layer 3 of the oxide film. The conductive polymer layer 5 is formed, and the electroformed conductive polymer layer 4 is
Almost the entire surface of the dielectric layer 3 of the oxide film is covered, and the inside of the through hole is also filled. The conductive polymer layer for cathode 5 is electrically connected to the electroformed conductive polymer layer 4 to form an electrolytic capacitor.

In this electrolytic capacitor, an electrolytic capacitor is formed between the anode valve metal foil 1 and the electrolytically formed conductive polymer layer 4 with the dielectric layer 3 of the oxide film interposed therebetween.
This electrolytically formed polymer layer 4 is formed in a wide area on the dielectric layer 3 of the oxide film, functions as a cathode, and can sufficiently increase the capacity.

Such an electroformed conductive polymer layer 4 comprises:
It is formed by a method of electrolytically oxidatively polymerizing the above monomer. In this embodiment, the cathode conductive polymer layer 5 is used as a part of the electrode 9a for electrolysis. The metal sheet 90 for electrolysis is previously formed on the surface of the conductive polymer layer 5 for cathode. That is, in this embodiment, the electrode 9a for electrolysis includes the metal sheet 90 for electrolysis and the conductive polymer layer 5 for cathode.

When an electric current is passed while the electrode 9a for electrolysis is used as a positive electrode and another electrode 9b in the solution is used as a negative electrode, an electrolytic polymerization reaction occurs on the conductive polymer layer 5 for a cathode as a positive electrode. . When the electrolysis is continued, a polymerization reaction continuously occurs at the interface of the produced polymer. The polymer reaches the surface of the valve metal foil 1, further fills or covers the through-hole 20, and emerges on the other surface side of the valve metal foil 1, and is integrated in the thickness direction while covering the metal foil 1. It grows continuously and a dense and uniform polymer layer is formed on the entire surface of the metal foil.

At least a portion of at least one of the valve metal 2, the cathode conductive polymer layer 5, and the electroformed conductive polymer layer 4 is provided with another conductive material such as a metal comb for anode extraction and cathode extraction, respectively. Are connected, and the whole is molded with resin or the like to obtain a final product.

The method for manufacturing the electrolytic capacitor of this embodiment will be described below. (A) as in the first embodiment
A metal foil is made, (b) the surface of the anode valve metal foil is anodized to form an oxide dielectric layer, and (c) a metal surface portion is formed on a part of the surface of the anode valve metal foil. Is done.

In this embodiment, the cathode conductive polymer layer 5 is formed on one side of the anode valve metal foil 1 as an electrode 9a for electrolysis for (d) electrolytic polymerization. In this step, a conductive polymer layer is previously formed or attached to the metal sheet 90 for electrolysis, and the oxide film layer 3 is formed on the conductive polymer layer 5.
Attach the valve metal foil so that it comes into contact.

The metal sheet 9 for electrolysis is used as the electrode 9a for electrolysis.
0 (for example, a nickel sheet), the conductive polymer layer 5 for a cathode is attached or formed on the nickel sheet. For example, the conductive polymer layer 5 may be formed from a polymerizable conductive monomer, for example, pyrrole, and a polymer, for example, a layer of polypyrrole on one surface of the metal sheet 90 for electrolysis by electrolytic oxidation polymerization. The conductive polymer layer 5 may be mechanically pressed in advance on the electrolysis metal sheet 90 of the electrolysis electrode 9a.

The valve metal foil 1 was brought into close contact with the cathode conductive polymer layer 5 on the electrode for electrolysis, and as shown in FIG.
The oxide film layer 3 is brought into contact with the polymer layer 5. The polymer layer 5 may be mechanically pressed against the oxide film layer 3 and fixed to the valve metal foil 1.

(E) Next, an electrolytically formed conductive polymer layer electrically connected to the conductive polymer layer for a cathode is formed on the dielectric layer of the oxide film of the metal foil. As shown in FIG.
The valve metal foil 1 carried on the electrode for electrolysis 9a in the previous step is:
The electrode is immersed in a conductive monomer solution and subjected to electrolytic treatment using the electrode 9a as a positive electrode to form an electroformed conductive polymer layer on the surface of the valve metal foil. In this electrolytic polymerization step, the electrode 9a for electrolysis is used as a positive electrode, and another electrode 9
As b, a current is caused to flow in such a manner that the nickel sheet having the same area as the negative electrode is opposed to the monomer solution 11 (eg, a pyrrole solution) filled in the container 10. A new polymer is formed starting from the conductive polymer layer 5 for the cathode by electrolysis and fills or covers the through hole 2 of the valve metal foil 1 while the electroformed conductive polymer is mainly formed as shown in FIG. The conductive polymer layer 4 is formed. An electric current is passed for a predetermined time to form the electroformed conductive polymer layer 4.

By the above steps, when the nickel sheet as the metal sheet 90 for electrolysis is finally peeled off from the interface with the conductive polymer layer 5 for the cathode, FIGS.
An electrolytic capacitor as shown in (A) and (B) is obtained.

In the above steps (d) and (e), as the cathode electrode 9a, the cathode conductive polymer layer 5 is sufficiently thick.
If the electric resistance is sufficiently low, the metal sheet for electrolysis 90
Is not necessary. As this electrolysis step, FIG.
As shown in (B), a method in which a current is passed between the conductive polymer layer 5 for the cathode and the counter electrode 9b to perform electrolysis may be adopted.

Also in this embodiment, the above step (e)
In the above, as described above, a conductive layer can be formed on the dielectric oxide film 3 in advance, and the electroformed conductive polymer layer 4 can be formed thereafter by an electrolytic oxidation polymerization method.

According to this manufacturing method, it is possible to easily form an electrolytically formed conductive polymer layer electrically connected to the conductive polymer layer for a cathode on the dielectric oxide film, and sufficiently close to the design capacity. It is possible to easily obtain an electrolytic capacitor capable of extracting a large capacity.

In the method of the present invention, starting from the conductive polymer layer for the cathode formed or arranged on one side of the valve metal foil for the anode, the electrolytic formation is carried out simultaneously mainly in the thickness direction of the valve metal foil for the anode. Since the conductive polymer layer can be formed integrally and continuously, it is possible to form the conductive polymer layer in a short time and easily compared to the conventional method, and the manufacturing process is simplified. And the manufacturing cost can be reduced.

(Embodiment 3) In this embodiment, a cathode conductive polymer layer 5 is formed on one side of an anode valve metal foil 1 on an oxide film dielectric layer 3 in FIG. Almost the entire surface of the dielectric layer 3 of the oxide film is covered with the electroformed conductive polymer layer 4, and the polymer layer 4 also includes the inside of the through hole. The cathode current collector 13 is electrically connected to the electrolytically formed conductive polymer layer 4 through the cathode conductive polymer layer 5 to form an electrolytic capacitor. This electroformed polymer layer is formed in a wide area on the dielectric layer of the oxide film 3 and functions as a cathode,
The capacity can be sufficiently increased. Further, a cathode metal foil 13 electrically connected to the electroformed conductive polymer layer 4 is formed, and the cathode metal foil 13 is used for lead extraction.

The valve metal 2 and the current collector 13 for the cathode
A different conductive material such as a metal comb is connected to the anode and the cathode, and the whole is molded with a resin or the like to obtain a final product.

A method for manufacturing the electrolytic capacitor of the present invention will be described below. In the manufacturing method of this embodiment, a step of forming a through-hole in the valve metal foil for the anode to roughen the foil surface, and anodizing the surface of the valve metal foil for the anode to form a dielectric layer of an oxide film This step and the step of forming a metal surface part on a part of the surface of the anode valve metal foil are the same as the steps (a) to (c) of the above-described manufacturing method.

(D) Next, a conductive polymer layer for the cathode is formed or arranged on one side of the valve metal foil for the anode. In this step, a conductive polymer layer is formed or attached to a metal foil serving as the cathode current collector 13, and a valve metal foil is attached to the conductive polymer layer so that the oxide film layer 3 contacts. I do.

One example of this step is that a metal foil or a sheet (for example, a nickel sheet) is used as the electrode sheet 90 for the electrolysis as the cathode current collector 13 and the one side surface of the nickel sheet is polymerized. The conductive polymer layer 5 is formed from a possible conductive monomer, for example, pyrrole by a polymer layer by an electrolytic oxidation polymerization method. In this step, the conductive polymer layer 5 may be mechanically pressed on the electrode sheet 90 for electrolysis in advance.

Next, the valve metal foil 1 is disposed on the conductive polymer layer 5 for the cathode, and the oxide film layer 3 is brought into contact with the polymer layer 5 as shown in FIG. The polymer layer 5 may be mechanically pressed against the oxide film layer 3 and fixed to the valve metal foil 1. (E) Next, an electrolytically formed conductive polymer layer electrically connected to the conductive polymer layer for the cathode is formed on the dielectric layer of the oxide film of the valve metal foil.

As shown in FIG. 11 (B), the valve metal foil 1 carried on the electrode sheet for electrolysis 90 (cathode current collector 13 (nickel sheet)) in the previous step was placed in a conductive monomer solution. It is immersed and subjected to electrolytic treatment using the electrode sheet for electrolysis 90 as a positive electrode to form an electroformed conductive polymer layer on the valve metal foil surface. In this electrolytic polymerization step, the electrode sheet for electrolysis 90 (the current collector 13 for the cathode) and the conductive polymer layer for the cathode are used as the positive electrode of the electrode for electrolysis 9a, and a nickel sheet having the same area as the counter electrode 9b is used as the negative electrode. An electric current is caused to face the monomer solution 11 (for example, a pyrrole solution) filled in the container 10.

As shown in FIG. 12, polypyrrole as the electroformed conductive polymer layer 4 is polymerized mainly in the direction of the arrow, starting from the cathode conductive polymer layer 5 on the cathode current collector 13 by electrolysis. The polymer is grown while the current is flowing, and a current is passed for a certain period of time to form the electroformed conductive polymer layer 4. Through the above steps, an electrolytic capacitor as shown in FIGS. 9 and 10A and 10B is obtained. This electrolytic capacitor is provided with the current collector 13 for the cathode, so that an electrolytic capacitor whose capacity can be easily taken out can be obtained.

(Embodiment 4) The electrolytic capacitor of this embodiment has a multilayer structure by laminating unit electrolytic capacitors each including an anode valve metal foil and a cathode conductive polymer layer. In the multilayer electrolytic capacitor shown in FIG. 13, a plurality of electrolytic capacitors shown in FIG. 5 are stacked with their main surfaces alternately stacked. The anode extraction electrode 7 is electrically connected to the valve metal 2 and metal surface 6 of all the individual unit capacitors, and is electrically insulated from the conductive polymer layer 5 for the cathode and the conductive polymer layer 4 formed by electrolysis. Have been.

The cathode extraction electrode 8 is electrically connected to each of the conductive polymer layers for cathode 5 and each of the electroformed conductive polymer layers 4, and is electrically insulated from the metal surface portion 6. . Such a laminated body of capacitors is further entirely molded with an encapsulating resin to obtain a final molded body of an electrolytic capacitor. In the electrolytic capacitor of this example, the unit capacitor itself has a large capacity, and a plurality of the unit capacitors are stacked and integrated to easily obtain a small-sized and large-capacity electrolytic capacitor.

Such a laminated electrolytic capacitor can be manufactured by the following method. (A) as a step of laminating a plurality of electrolytic capacitors,
Electrolytic capacitors as shown in FIGS. 5A and 5B are used as unit capacitors. In this example, four unit capacitors have the same metal surface portion 6 of each unit capacitor as shown in FIG. Stacked.

(B) These unit capacitors are electrically connected at the metal surface of the valve metal foil for the anode,
Integrated into one capacitor. The metal surface portions 6 of the stacked individual electrolytic capacitors are physically fixed and electrically connected. In this step, an appropriate method such as a method of attaching a nickel sheet as the anode electrode 7 with a conductive adhesive, a method of press-fitting with a metal fitting or the like, a method of welding, and a method combining these methods is used. Can be. As for the material for integration, metals and resins are used if the above requirements are satisfied.

(C) The conductive polymer layer for the cathode of the valve metal foil for the anode is electrically connected and integrated. The stacked individual electrolytic capacitors are physically fixed in the conductive polymer layer for cathode 5 or the conductive polymer layer 4 formed by electrolysis, and are electrically connected. Specific methods for integration include a method of attaching a metal as the cathode extraction electrode 8, for example, a nickel sheet, with a conductive adhesive, a method of pressing with a metal fitting, or the like, and a method of chemically polymerizing a conductive polymer. A method of forming and integrating by an electrolytic oxidation polymerization method can be used. As a material for further integrating, a metal or a resin is used if the above requirements are satisfied. The step (b);
The step of (c) may be replaced with the preceding and following steps.

Through the above steps sequentially, an electrolytic capacitor as shown in FIG. 13 is obtained. Further, it is preferable to mold the entire product with a resin or the like to obtain a final product.

According to this manufacturing method, as a result of laminating and integrating a plurality of capacitor units each capable of sufficiently taking out the capacitance with respect to the design value, a small and large-capacity electrolytic capacitor can be easily obtained. The number of stacked electrolytic capacitors is appropriately adjusted according to the dimensions and capacitance of the final electrolytic capacitor. The electrolytic capacitor of the present invention,
A unit electrolytic capacitor including a valve metal foil for an anode and a conductive polymer layer for a cathode is laminated to form a multilayer structure. In this example, the electrolytic capacitor shown in FIG. 5 was used as a unit electrolytic capacitor to be laminated, and a laminated multilayer structure was used. In addition, the electrolytic capacitors shown in FIGS. 1 and 9 were laminated as a unit electrolytic capacitor. In this case, the same effect can be obtained.

(Embodiment 5) The method of manufacturing an electrolytic capacitor according to the present invention may further include a step of re-anodizing a part of the valve metal foil for an anode. In this case, (a) unit electrolytic capacitors are laminated, (b) the metal surface portion of the anode valve metal foil is electrically connected and integrated, and (c) a part of the anode valve metal foil is re- Oxidized. In the step of re-anodizing, the anode valve metal foil other than the metal surface of the laminated electrolytic capacitor is again anodized in an anodizing solution to form an aluminum oxide layer. In this step, as a means for oxidizing, a conventional method of a constant current type in a anodic oxidation solution or a constant voltage anodic oxidation can be used. Further, after the anodizing treatment, the conductive polymer layer for the cathode is electrically connected and integrated.

According to this manufacturing method, partial damage of the dielectric layer of the oxide film caused by mechanical stress generated in the laminating step and the step of integrating the metal surface portion is repaired in the subsequent step (c). It is possible to do. as a result,
The obtained electrolytic capacitor has higher reliability.

(Embodiment 6) This embodiment includes a winding type electrolytic capacitor, in which a unit electrolytic capacitor including an anode valve metal foil and a cathode conductive polymer layer is wound in a coil shape to form a multilayer. It has a structure. FIGS. 14A and 14B show examples of a wound electrolytic capacitor.

FIG. 14A shows that a unit electrolytic capacitor as shown in FIG. 1B or FIG. 5 is formed from a long anode valve metal foil 2 and one end of the valve metal foil 1 is provided with a metal. The surface 6 is exposed, and this long unit electrolytic capacitor is wound from the other end side into a coil shape, and the surface metal portion 6 at the one end portion is formed on the outer peripheral surface of the coil. An anode lead is attached from the surface metal portion 6, and a cathode lead is attached to at least a part of at least one of the cathode conductive polymer layer 5 and the electrolytically formed conductive polymer layer 4, thereby forming a capacitor. It is possible to obtain a small and large-capacity electrolytic capacitor. The wound type can easily change the capacitance only by changing the length of the electrolytic capacitor, thereby facilitating the manufacture.

FIG. 14B shows another winding type electrolytic capacitor in which a unit electrolytic capacitor is formed from a long anode valve metal foil 1, and a surface metal 6 is formed on a side edge of the valve metal foil 1. Is formed, and the unit electrolytic capacitor is wound in from the end side, and the surface metal part 6 of the side edge is formed at the end of the formed coil.

As the anode lead, another conductive material, for example, a metal comb is connected to the valve metal 2. Further, after another conductive material for a cathode, for example, a metal comb, is connected to at least one part of the conductive polymer layer for cathode 5 and the electroformed conductive polymer layer 4, the whole is molded with a resin or the like. To form a final electrolytic capacitor.

As a method of fixing after winding, if the requirement that the metal surface portion 6 and the conductive polymer layer 5 for cathode are electrically insulated is satisfied, the resin is bonded with a resin such as an epoxy resin. Methods are also available.

In order to obtain a final product, the metal surface portion 6 made of the valve metal 2 is electrically insulated from the conductive polymer layer 5 for the cathode and the conductive polymer layer 4 formed by electrolysis.
An anode extraction electrode (not shown) electrically connected to
Forming a cathode extraction electrode (not shown) electrically insulated from the metal surface portion 6 and electrically connected to the conductive polymer layer for cathode 5 and the electroformed conductive polymer layer 4; Is covered with a molding resin (not shown).

(Embodiment 7) In the production of a wound electrolytic capacitor, a step of re-anodizing can be employed.
With respect to the electrolytic capacitor wound in a roll shape, the anode valve metal foil is re-anodized except for the metal surface portion for connection. In this step, the anodized valve metal foil for the wound electrolytic capacitor is again anodized in the anodizing solution,
An aluminum oxide layer is formed. In this step, a conventional method of constant voltage anodic oxidation or constant current anodic oxidation in an anodizing solution is employed.

This re-anodization makes it possible to repair partial damage to the dielectric layer of the oxide film caused by mechanical stress generated in the step of winding the unit electrolytic capacitor. As a result, the obtained electrolytic capacitor has higher reliability.

[0089]

EXAMPLES (Example 1) (a) First, an anode valve metal foil 1 having a through-hole and having a roughened surface was prepared. Purity 99. 98% or more and thickness 10
An aluminum foil (soft material) having a thickness of 0 μm, a width of 5 mm, and a length of 13 mm was prepared. Next, as means for forming through-holes in the anode valve metal foil, 50 through-holes having a diameter of 0.2 mm were formed on the surface of the aluminum foil using a punching machine.
It was formed with a density of m ² . Further, as a means for roughening the surface of the valve metal foil for anode 1, a hydrochloric acid solution having a concentration of 10 wt% and a liquid temperature of 30 ° C. was used as an electrolytic solution with respect to the aluminum foil having the through-hole, and the current density was 0.2 A / cm ² , frequency 2
AC etching was performed at 0 Hz.

(B) Next, as a step of oxidizing the surface of the valve metal foil for anode 1 to form the dielectric layer 3 of an oxide film, an aqueous solution of ammonium adipate having a liquid temperature of 60 ° C. and a concentration of 5 wt% is used. Was used as an anodizing solution, and a constant voltage anodizing was carried out at an anodizing voltage of 20 V to form aluminum oxide as a dielectric layer 3 of an oxide film on the surface of the valve metal foil for the anode.

(C) Next, as a step of forming the metal surface portion 6 on a part of the surface of the anode valve metal foil 1, a part of the aluminum oxide (the anode valve metal foil 1) on the surface of the anode valve metal foil 1 is formed. End portion, width 5 mm × length 2 mm) was polished off with sandpaper to form an exposed aluminum surface as the metal surface portion 6. The capacitance of the entire dielectric oxide film on the aluminum foil obtained from the above process was determined to be 50 mS.
As a result of measurement at 10 Hz in an aqueous solution of ammonium borate (cm / cm) (hereinafter referred to as foil capacity), the average value was 28.2 μF.

(D) Next, the electrode 9a for electrolysis was arranged on one side of the valve metal foil for anode 1 except for the metal surface portion 6. A nickel sheet having a width of 10 mm, a length of 20 mm, and a thickness of 50 μm was prepared as the metal sheet 90 for electrolysis. An aluminum foil as the anode valve metal foil 1 is placed on the nickel sheet while paying attention so that the metal surface portion 6 does not contact the nickel sheet, and the oxide film layer 3 is placed on the electrode sheet 90 for electrolysis.
Was contacted.

(E) Next, an electroformed conductive polymer layer 4 was formed on the oxide film dielectric layer 3 as follows. The monomer solution contains 1 mol / l of pyrrole as a monomer.
And sodium aaryl sulfonate as an electrolyte
A 10% aqueous solution of isopropyl alcohol containing wt% was used.

After the monomer solution 11 was adjusted to 20 ° C., the valve metal foil 1 disposed on the electrode for electrolysis 9a was immersed in the solution, and as shown in FIGS. 3B and 4, Separately, as an electrode 9b for electrolysis, a nickel sheet having a width of 10 mm, a length of 20 mm, and a thickness of 50 μm was arranged at an interval of 1 cm to face the sample.

Using the electrode 9a for electrolysis as a positive electrode, a voltage of 10 V was applied for 5 minutes to electrolytically polymerize polypyrrole as the electroformed conductive polymer layer 4. Thereafter, the peeled nickel sheet as the electrode for electrolysis 9a was placed on the valve metal foil 1
Peeled off.

(F) Further, a nickel sheet as the stripped electrode sheet 90 for electrolysis was disposed on the surface of the anode valve metal foil 1 opposite to the previous one by the same method as in the above step (d). Subsequently, the nickel sheet was used as a positive electrode, and a current was applied for 5 minutes in the same manner as in the above step (e) to further form an electroformed conductive polymer layer 4 on the dielectric oxide film 3. The electrolytically formed conductive polymer layer 4 in this embodiment is formed by polymerization (electrolytic oxidation polymerization) by applying a current for a total of 10 minutes. Through the above steps, an electrolytic capacitor having a configuration as shown in FIG. 1B was obtained.

(G) A conductive adhesive (not shown) containing carbon and a silver paste (not shown) are deposited on polypyrrole as the electroformed conductive polymer layer 4 of the electrolytic capacitor selected through the above steps in order. As shown in FIG. 15, an L-shaped nickel sheet as the cathode extraction electrode 8 was bonded and fixed to the end of the electrolytic capacitor. At the other end, an L-shaped nickel sheet as an anode extraction electrode 7 was welded to the metal surface 6 and fixed. Subsequently, the entire electrolytic capacitor carrying a nickel sheet as the anode extraction electrode 7 and a nickel sheet as the cathode extraction electrode 8 is molded using an epoxy resin (not shown), and finally both ends are polished. Thus, the surface of the nickel sheet as the anode extraction electrode 7 and the surface of the nickel sheet as the cathode extraction electrode 8 were exposed to form an element.

(Embodiment 2) In this embodiment 2, first, the anode valve metal foil 1 is obtained through the same steps as (a), (b) and (c) in the above (embodiment 1). Was.

(D) Next, the conductive polymer layer 5 for the cathode was formed on the one side of the valve metal foil 1 for the anode except for the metal surface portion 6. First, as the electrode 9a, a width of 10 mm and a length of 20 m
m, a nickel sheet having a thickness of 50 μm was prepared. On one surface of the nickel sheet, polypyrrole as a conductive polymer layer 5 for a cathode having a width of 5 mm, a length of 9 mm, and a thickness of 20 μm was formed by an electrolytic oxidation polymerization method.

An aluminum valve metal foil was placed on the polypyrrole on the surface of the nickel sheet so that the metal surface 6 did not contact the polypyrrole.
A sample as shown in FIG. 7 (A) was prepared by applying a pressure of g / cm ² and temporarily compressing.

(E) The sample was the monomer solution 1 of Example 1.
Electrolytic polymerization was performed in 1 to form an electroformed conductive polymer layer. The above sample is immersed in this monomer solution 11,
As shown in FIGS. 7B and 8A, the other electrode 9
As b, a nickel sheet having a width of 10 mm, a length of 20 mm, and a thickness of 50 μm was arranged at an interval of 1 cm to face the sample.

The nickel sheet of the electrolysis electrode 9b on which the sample was temporarily pressed was used as a positive electrode, and a voltage of 10 V was applied for 10 minutes to polymerize and form polypyrrole as the electroformed conductive polymer layer 4 (electrolytic oxidation polymerization method). )did. After the polymerization, the electrode 9b for electrolysis was peeled off from the conductive polymer layer 5 for cathode to obtain an electrolytic capacitor.

(F) The electrolytic capacitors selected through the above-described steps are provided with a conductive adhesive containing carbon (not shown) and a silver paste (not shown) on the conductive polymer layer 5 for cathode made of polypyrrole. ) To form a cathode extraction electrode 8.

The cathode extraction electrode 8 was bonded and fixed to the end of the electrolytic capacitor using an L-shaped nickel sheet as shown in FIG. At the other end, an L-shaped nickel sheet as an anode extraction electrode 7 is provided with a metal surface portion 6.
Welded and fixed. Subsequently, the entire electrolytic capacitor carrying a nickel sheet as the anode extraction electrode 7 and a nickel sheet as the cathode extraction electrode 8 is molded using an epoxy resin (not shown), and finally both ends are polished. Thus, the surface of the nickel sheet as the anode extraction electrode 7 and the surface of the nickel sheet as the cathode extraction electrode 8 were exposed to form an element.

Example 3 In this example, the anode valve metal foil of Example 1 was used. (D) The conductive polymer layer 5 for the cathode was formed as follows, except on the metal surface portion 6 and on one side of the valve metal foil 1 for the anode. As the metal foil 13 for the cathode, width 5 mm, length 20 mm, thickness 3
Using a 0-μm nickel foil, polypyrrole as a conductive polymer layer 5 for a cathode was formed on one surface of the one side thereof by electro-oxidation polymerization at a width of 5 mm, a length of 9 mm, and a thickness of 20 μm.

An aluminum foil as the anode valve metal foil 1 was placed on the polypyrrole on the nickel foil surface in Example 2.
The sample was arranged in the same manner as described above, and temporarily press-bonded at the same pressure by a press machine to produce a sample as shown in FIG.

(E) Next, a step of forming an electroformed conductive polymer layer electrically connected to the cathode conductive polymer layer 5 on the oxide film dielectric layer 3 was carried out as follows. .
The above sample was immersed in the monomer solution 11 prepared in Example 1, and as shown in FIGS. 11B and 12, the other electrode 9b was 10 mm wide, 20 mm long and 5 mm thick.
A nickel sheet of 0 μm was placed at an interval of 1 cm opposite to the sample, and then electrolytically polymerized to form polypyrrole. Thereafter, the coating applied to prevent excess polypyrrole from being polymerized was peeled off to obtain an electrolytic capacitor having a configuration as shown in FIG.

(F) The cathode metal foil 13 of the electrolytic capacitor obtained through the above-described steps was bent into an L-shape, and an extra portion was cut off. At the other end, an L-shaped nickel sheet as an anode extraction electrode 7 was welded to the metal surface 6 and fixed to obtain an electrolytic capacitor as shown in FIG. Subsequently, the entire electrolytic capacitor carrying a nickel sheet as the anode extraction electrode 7 and a nickel foil as the metal foil 13 for the cathode is molded using an epoxy resin (not shown), and both ends are finally polished. Thus, the surface of the nickel sheet as the anode extraction electrode 7 and the surface of the nickel foil as the cathode metal foil 13 were exposed to form an element.

(Embodiments 4 to 6) The embodiments 4 to 5 and the embodiment 6 described below correspond to the electroformed conductive polymer layer 4
Examples 1 to 3 except that a manganese dioxide layer (not shown) was formed as a conductive layer directly on the oxide film before the step of forming a layer by electrolytic oxidation polymerization.
And the same configuration and manufacturing method. That is, the anode devices according to Examples 4 to 6 are different from the above-described Examples 1 to 3, respectively. The difference is that an electroformed conductive polymer layer formed by a polymerization method is constituted.

The formation of the conductive layer in each example was performed by the following method. The valve metal foil for an anode according to the steps (a) to (c) in Example 1 was immersed in manganese nitrate for 5 minutes, and then heat-treated at 250 ° C. for 10 minutes to thermally decompose the manganese nitrate. A manganese dioxide layer (not shown) was formed on the oxide film dielectric layer 3.

After the formation of the conductive layer, each element was manufactured by the same steps as those in Examples 1, 2 and 3 except for the step of forming the conductive layer. Example 5 and Example 6 were used.

Comparative Example (a) As a step of preparing a valve metal foil for an anode having a roughened surface, the purity was 99.98% or more, the thickness was 100 μm, and the width was 5 mm.
An aluminum foil (soft material) having a thickness of 13 mm and a length of 13 mm was prepared, and the surface was roughened and anodized by the same process as in Example 1 (a) except that the aluminum foil had no through hole. An anode valve metal foil was obtained. The foil capacity of the entire dielectric oxide film on the obtained aluminum foil was measured by the same measuring method as in Example 1 above. As a result, 28.4 μF (10H
z).

(D) A manganese dioxide layer is formed by thermal decomposition of manganese nitrate on the surface of aluminum oxide on an aluminum foil having no through-hole as an anode valve metal foil obtained by the above-described steps, and this manganese dioxide layer is formed. Was used as an electrode. Specifically, it is immersed in manganese nitrate for 5 minutes, and then heat-treated at 250 ° C. for 10 minutes to thermally decompose the manganese nitrate and form a manganese dioxide layer (not shown) on the dielectric layer 3 of the oxide film. ) Formed.

Further, in the same manner as in Example 1, a conductive polymer layer for a cathode was formed using the above monomer solution. In this monomer solution 11, a nickel sheet having a width of 10 mm, a length of 20 mm, and a thickness of 50 μm as an electrode 9 and the above-mentioned aluminum foil on which manganese dioxide was formed were opposed to each other and supported at an interval of 1 cm. Next, after adjusting the liquid temperature of the monomer solution 11 to 20 ° C., the manganese dioxide layer side was set as a positive electrode, and a voltage of 10 V was applied for 10 minutes in the same manner as described above (Example 1) to form polypyrrole by polymerization (electrolytic oxidation). Polymerization method).

(E) A nickel sheet as an anode extraction electrode and a nickel sheet as a cathode extraction electrode are fixed to the electrolytic capacitor selected through the above steps in the same manner as in Example 1 (f). After molding the whole with an epoxy resin, both ends were polished to obtain an element.

The capacity (hereinafter, referred to as element capacity) of each of ten electrolytic capacitors obtained in Examples 1 to 6 and Comparative Example was measured. Table 1 shows the results of the capacitance measurement. The values in the table are the average values of the results of measurements performed on 10 samples.

[0117]

[Table 1]

As is clear from Table 1, the electrolytic capacitors of Examples 1 to 6 according to the present invention are superior in the capacity achievement ratio with respect to the design value as compared with the aluminum solid electrolytic capacitor of the comparative example according to the conventional method. Comparative examples are
The capacity achievement rate is extremely low. It is considered that the formation of polypyrrole as a conductive polymer by the electrolytic oxidation polymerization method is insufficient for 10 minutes.

On the other hand, in the case of the first embodiment according to the present invention, starting from the electrode for electrolysis arranged on one side of the valve metal foil for anode, the electroformed conductive film is formed all at once in the thickness direction of the valve metal foil for anode. As a result of being able to form the polymer layer integrally and continuously, the conductive polymer layer can be formed in a shorter time (total 10 minutes in the first embodiment) as compared with the conventional method, It is considered that a sufficient capacity achievement ratio can be obtained.

Similarly, in the case of Examples 2 and 3 according to the present invention, the conductive polymer layer for the cathode formed or arranged on one side of the valve metal foil for the anode is also used as a starting point, and mainly the anode-use conductive polymer layer. As a result of being able to integrally and continuously form this electroformed conductive polymer layer in the thickness direction of the valve metal foil, a shorter time (10 minutes in this embodiment) than in the conventional method It is considered that a conductive polymer layer could be formed on the substrate and a sufficient capacity achievement ratio could be obtained.

Further, Examples 3 to 6 according to the present invention are more excellent in achieving the capacity than Examples 1 to 3 according to the present invention. Examples 3 to 3 of the present invention
As for No. 6, in addition to the effects of the above-described Examples 1 to 3, the conductive layer was formed in advance, so that the oxidation was performed by the electroformed conductive polymer layer formed in the same polymerization time (10 minutes in this example). It can be said that this is the result of the coating of the dielectric layer of the coating being more complete. That is, it can be said that the formation of the conductive layer on the oxide film enables more efficient production.

(Example 7) An electrolytic capacitor was manufactured in the same manner as in the steps (a) and (b) of Example 2. The foil capacity of the aluminum foil used for the electrolytic capacitor was 10 H in an aqueous ammonium borate solution of 50 mS / cm.
It was 28.2 μF as measured by z.

(F) Next, as a step of laminating a plurality of electrolytic capacitors, four electrolytic capacitors selected through the above-described steps are sequentially laminated as shown in FIG. did.

(G) Next, as a step of integrating the metal surface portions of the valve metal foil for the anode, the metal surface portions 6 of the individual electrolytic capacitors and the nickel sheet as the anode extraction electrode 7 are joined by welding and integrated. did.

(H) Next, as a step of integrating the conductive polymer layer for the cathode, a conductive adhesive containing carbon (not shown) on polypyrrole as the conductive polymer layer for the cathode 5 of the electrolytic capacitor, and Using a silver paste (not shown), an L-shaped nickel sheet as a cathode extraction electrode 8 was formed as shown in FIG.
As shown in FIG. 8, it was adhesively fixed to the end of the electrolytic capacitor.

Finally, the entire electrolytic capacitor carrying a nickel sheet as the anode lead-out electrode 7 and a nickel sheet as the cathode lead-out electrode 8 is molded using an epoxy resin (not shown), and both ends are finally polished. By doing so, the surface of the nickel sheet as the anode extraction electrode 7 and the surface of the nickel sheet as the cathode extraction electrode 8 were exposed to obtain an electrolytic capacitor element.

The capacity of the electrolytic capacitor obtained through the above steps (hereinafter, referred to as element capacity) was evaluated. Table 2 shows the results of the capacitance measurement. Note that the values in the table are the average values of the results obtained by measuring 10 samples. In the column of foil capacitance, a value of four times the above-mentioned foil capacitance (28.2 μF) (for four layers of unit electrolytic capacitors) is described.

[0128]

[Table 2]

As is apparent from Table 2, no remarkable decrease in capacity due to the lamination was observed. That is, as a result of laminating and integrating a plurality of unit capacitors each capable of sufficiently taking out the capacitance with respect to the design value, a small and large-capacity electrolytic capacitor can be easily obtained.

[0130]

As described above, the electrolytic capacitor according to the present invention is formed by oxidizing a part of the surface of the anode valve metal foil having a through hole and having a roughened surface, and a part of the surface of the anode valve metal foil. Since it has a dielectric layer of an oxide film and a cathode layer of an electroformed conductive polymer layer, it is possible to easily obtain an electrolytic capacitor that can take out a sufficiently high capacity close to the designed capacity from the anode valve metal foil. Becomes

Further, the electrolytic capacitor according to the present invention has an anode valve metal foil having a through-hole and a roughened surface, and an oxide film formed by oxidizing a part of the surface of the anode valve metal foil. A body layer, a conductive polymer layer for a cathode on at least one side of a metal foil, and an electroformed conductive polymer layer electrically connected to the conductive polymer layer for a cathode on a dielectric layer of an oxide film. With such a configuration, it is possible to easily obtain an electrolytic capacitor capable of sufficiently taking out the capacitance with respect to the design value.

Further, by forming the electrolytic capacitor in a laminated or wound structure, a small-sized and large-capacity electrolytic capacitor can be easily obtained.

In the method of manufacturing an electrolytic capacitor according to the present invention, when the conductive polymer layer is formed by electrolytic polymerization, the electrolytic electrode formed or arranged on one side of the anode valve metal foil having a large number of through holes is electrolyzed. Since it is a method of polymerizing a monomer at the starting point of polymerization, the polymer layer formed extends from the electrode surface to the opposite surface of the anode valve metal foil through the through hole, and further covers this surface. Further, it becomes possible to form the electrolytically-formed conductive polymer layer densely and continuously mainly in the thickness direction of the valve metal foil for the anode at the same time.
As a result, the production method of the present invention makes it possible to form a conductive polymer layer in a short time and easily as compared with the conventional electrolysis method, thereby simplifying the production process and reducing the production cost. It becomes possible.

In the production method of the present invention, as the electrode for electrolysis,
If the conductive polymer layer for the cathode is formed in advance on one side of the valve metal foil, the electrode for electrolysis is formed together with the electroformed conductive polymer layer formed on the opposite side of the valve metal foil and in contact with the oxide film dielectric layer. Can be used as a cathode layer. Thus, if the electropolymerization treatment forms the electroformed conductive polymer layer only on one side of the valve metal foil, a conductive polymer layer as a cathode layer can be formed on both sides of the valve metal foil.

In the production method of the present invention, as the electrode for electrolysis,
If the cathode conductive polymer layer formed in advance on one side of the valve metal foil and the electrode metal sheet formed on the cathode conductive polymer layer are used, in the electrolytic polymerization step, the electrode metal sheet is It is used as a carrier for a metal foil, and the conductive polymer layer for a cathode can be used as an anode for forming an electroformed conductive polymer layer. Thus, there is an advantage that the electrode for electrolysis can be used as the cathode layer of the electrolytic capacitor together with the electroformed conductive polymer layer, and the electrode metal sheet can be used as it is as the cathode current collector in contact with the cathode layer.

Further, if a conductive layer is formed in contact with the dielectric layer in advance before the electrolytic polymerization, the conductive layer can be used as a starting point for a polymerization reaction of a new polymer layer. The growth of the molecular layer can be promoted, and the time required for the electrolytic polymerization can be shortened.

In the present invention, a multilayer electrolytic capacitor can be prepared by stacking a large number of unit electrolytic capacitors by using the above electrolytic capacitor as a unit electrolytic capacitor. The electrolytic capacitor can be small. Further, a wound electrolytic capacitor in which a unit electrolytic capacitor is wound in a coil shape can be prepared. Similarly, an electrolytic capacitor having a larger capacitor capacity and a smaller shape can be obtained.

[Brief description of the drawings]

FIG. 1 shows a schematic perspective view (A) of a valve metal foil for an anode according to an embodiment of the present invention, and a schematic perspective view (B) of an electrolytic capacitor of the present invention.

FIG. 2 shows a schematic cross-sectional view (A) of an electrolytic capacitor according to an embodiment of the present invention, and a partially enlarged view (B) of a cross-section of the electrolytic capacitor shown in (A).

FIG. 3 (A) is a schematic cross-sectional view showing an anode electrode metal foil disposed on one side of an anode valve metal foil in a manufacturing process of the electrolytic capacitor of the present invention, and FIG. A schematic perspective view (B) of the electrolytic cell showing the arrangement is shown.

FIG. 4 is a schematic cross-sectional view of an electrolytic cell showing a behavior of polymer formation in the electrolytic oxidation polymerization process of the electrolytic capacitor of the present invention.

FIG. 5 is a schematic perspective view of an electrolytic capacitor according to another embodiment of the present invention.

FIGS. 6A and 6B respectively show FIGS. 2A and 2B of an electrolytic capacitor according to another embodiment of the present invention. FIGS.

FIG. 7 (A) and (B) of another embodiment of the present invention.
(A) and (B) of FIG.

8 (A) and 8 (B) are schematic cross-sectional views of an electrolytic cell showing a behavior of polymer formation in an electrolytic oxidation polymerization process of an electrolytic capacitor according to another embodiment of the present invention.

FIG. 9 is a schematic perspective view of an electrolytic capacitor according to still another embodiment of the present invention.

FIG. 10 shows a further embodiment of the present invention.
(A) and (B), which are similar to FIGS.

FIG. 11 (A) of still another embodiment of the present invention.
(A) and (B), which are similar to FIGS.

FIG. 12 is a view similar to FIG. 4 of another embodiment of the present invention.

FIG. 13 is a schematic perspective view of a multilayer electrolytic capacitor according to another embodiment of the present invention.

FIG. 14 shows schematic perspective views (A) and (B) of a wound electrolytic capacitor according to another embodiment of the present invention.

FIG. 15 is a schematic perspective view of an electrolytic capacitor according to still another embodiment of the present invention.

FIG. 16 is a schematic perspective view of an electrolytic capacitor according to an embodiment of the present invention.

FIG. 17 is a schematic perspective view of an electrolytic capacitor according to still another embodiment of the present invention.

FIG. 18 is a schematic perspective view of a multilayer electrolytic capacitor according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve metal foil for anode 2 Anode layer 3 Dielectric layer of oxide film 4 Electrolytically formed conductive polymer layer 5 Conductive polymer layer for cathode 6 Metal surface 7 Anode extraction electrode 8 Cathode extraction electrode 9a Electrolysis electrode 9b Electrolysis Electrode 90 Electrode metal sheet 11 Monomer solution 13 Cathode current collector

Claims (21)

[Claims] 1. An anode layer of a valve metal foil having a through hole and a roughened surface, a dielectric layer of an oxide film formed by anodizing a part of the valve metal foil surface, and the dielectric layer An electrolytic capacitor comprising: an upper cathode layer; and wherein the cathode layer is an electroformed conductive polymer layer formed in contact with the dielectric layer of the oxide film. 2. A conductive polymer layer for a cathode is formed on one side of a valve metal foil, and an electroformed conductive polymer layer is formed on an opposite side of the valve metal foil to contact an oxide film dielectric layer. 2. The electrolytic capacitor according to claim 1, wherein the electrolytic capacitor is electrically connected to the cathode conductive polymer layer. 3. An electrolytic capacitor including a current collector, wherein the current collector is provided through a conductive polymer layer for a cathode on a surface of the valve metal foil.
3. The electrolytic capacitor according to claim 2, wherein the electrolytic capacitor is a metal sheet formed on one side of a valve metal foil for an anode. 4. The cathode layer further includes a conductive layer formed in contact with the dielectric layer, and the electroformed conductive polymer layer includes the conductive layer and is formed on the oxide film. 4. The electrolytic capacitor according to claim 1, wherein: 5. The electrolytic capacitor according to claim 1, wherein a metal surface portion for an electrode is formed on a part of the valve metal foil for an anode. 6. The electrolytic capacitor according to claim 1, wherein a radius of the through hole is equal to or less than a thickness of the anode valve metal foil. 7. The electrolytic capacitor according to claim 1, wherein an area ratio of the through hole to the main surface of the anode valve metal foil is 10% or less. 8. An electrolytic capacitor according to claim 5, wherein the electrolytic capacitor is laminated in a plurality of layers to form a laminate, and the laminate is electrically connected to the metal surface portion where a metal surface is exposed on a part of each metal foil. And a cathode extraction electrode electrically connected directly or indirectly to the electroformed conductive polymer layer. 9. An electrolytic capacitor in which the electrolytic capacitor according to claim 1 is wound to form a laminate. 10. The electrolytic capacitor according to claim 1, wherein the anode valve metal foil is aluminum. 11. An electroformed conductive polymer comprising a heterocyclic 5
The electrolytic capacitor according to any one of claims 1 to 3, wherein the electrolytic capacitor is a conductive polymer layer containing a polymer of a membered ring compound as a main component. 12. An anode layer of a valve metal foil having a through-hole and having a roughened surface, a dielectric layer of an oxide film formed by anodizing a part of the surface of the metal foil, and the dielectric layer. A method for manufacturing an electrolytic capacitor comprising: an upper electrode layer; an electrolytic electrode formed on one side of an anode valve metal foil; an anode valve metal foil in a conductive monomer liquid in which a separate electrode is disposed. Is immersed, and then electrolysis between the electrode for electrolysis and the electrode for electrolysis arranged in the liquid, the monomer is subjected to electrolytic oxidation polymerization to form the electroformed conductive polymer layer into the valve metal foil for the anode. A method for producing an electrolytic capacitor, comprising forming a cathode layer on an oxide film surface. 13. The electrode according to claim 12, wherein the electrode for electrolysis is a conductive polymer layer for cathode, and the conductive polymer layer for cathode and the conductive polymer layer formed by electrolysis are used for the cathode layer. 3. The method for manufacturing an electrolytic capacitor according to claim 1. 14. An electrode for electrolysis comprising a conductive polymer layer for a cathode and a metal sheet for electrolysis attached on the conductive polymer layer for a cathode; With the conductive polymer layer,
The method for producing an electrolytic capacitor according to claim 12, wherein the electrolytic metal sheet is used as a cathode layer, and the electrolytic metal sheet is used as a cathode current collector. 15. The method for manufacturing an electrolytic capacitor according to claim 12, further comprising a step of partially forming a conductive layer on the surface of the dielectric layer of the oxide film prior to the electrolytic step. 16. A manufacturing method further comprising: laminating a plurality of the above electrolytic capacitors in a laminate, connecting a common anode wiring electrode to a metal surface of each anode valve metal foil of the laminate, 2. The method according to claim 1, further comprising: connecting a common cathode wiring electrode to each electroformed conductive polymer layer of the body.
16. The method for manufacturing a multilayer electrolytic capacitor according to 2 or 15. 17. A manufacturing method further comprising: laminating a plurality of the above-described electrolytic capacitors in a laminate; connecting a common anode wiring electrode to a metal surface of each anode valve metal foil of the laminate; 16. The method according to claim 13, further comprising connecting a common cathode wiring electrode to each cathode conductive polymer layer of the body. 18. A manufacturing method further comprising: laminating a plurality of layers of the electrolytic capacitor according to claim 14 or 15 on a laminate, wherein a common anode for the metal surface portion of each anode valve metal foil of the laminate is provided. And connecting a common cathode wiring electrode to each cathode current collector of the multilayer body. 19. The method according to claim 19, further comprising: reconnecting a part of the anode valve metal foil after the metal surface portion is connected to the anode wiring electrode and before the cathode wiring electrode is electrically connected. The method according to any one of claims 16 to 18, comprising anodizing. 20. A method for manufacturing a wound electrolytic capacitor, further comprising winding the electrolytic capacitor according to claim 12 into a roll. 21. The method for manufacturing an electrolytic capacitor according to claim 20, wherein the manufacturing method further includes a step of re-anodizing a part of the valve metal foil for an anode after winding the electrolytic capacitor into a roll shape.