JPH11219861A - Electrolytic capacitor and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide an electrolytic capacitor having a conductive polymer layer as a cathode to reduce impedance and improve high-frequency response. SOLUTION: The current collector metal for the cathode and the surface of the dielectric layer of the anode valve metal porous body are directly joined to each other with a conductive polymer layer without using various joining layers (carbon layer or silver layer). The impedance is reduced by roughening at least the surface of the current collector metal that is bonded to the conductive polymer. Alternatively, the impedance is reduced by embedding carbon particles in at least the surface of the current collector metal for the cathode that is to be bonded to the conductive polymer, or by forming a carbon thin film layer on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic capacitor using a valve metal such as aluminum or tantalum as an anode, a valve metal oxide film as a dielectric, and a conductive polymer layer as a cathode, and a method of manufacturing the same. Things.

[0002]

2. Description of the Related Art Conventionally, an electrolytic capacitor using a valve metal such as aluminum or tantalum has a porous valve metal body as an anode element, and an oxide film of the valve metal as a dielectric layer on the surface of the pores of the porous body and outside. It is common to form an exterior on the surface, using an electrolyte solution or an inorganic solid electrolyte for the cathode, providing a collector metal part connected to the anode and the cathode, respectively. For example, in an aluminum electrolytic capacitor, an organic solvent containing an organic acid or the like has been used as a cathode, and in a tantalum electrolytic capacitor, manganese dioxide or the like has been used as a cathode.

In recent years, high-frequency response of electronic components has been demanded in response to digitization of circuits, and improvement of high-frequency response by lowering the resistance of electrolytic capacitors has also been demanded. Under such circumstances, use of a conductive polymer compound having high conductivity as a cathode electrolyte of an electrolytic capacitor has been studied and developed.

In the case of an electrolytic capacitor, an oxide film is formed on the pore surface and the outer surface of a porous valve metal body, and the oxide film is used as a dielectric layer. The anode is used. Therefore, when a cathode is formed on this capacitor element, it is necessary to efficiently cover the surface of the pores of the very complicated porous element with a conductive polymer.

When the conductive polymer is formed as the solid electrolyte for the cathode, when the electrolytic oxidation polymerization method is used, the dielectric layer surface of the pore surface of the very complicated porous element is efficiently made to have high conductivity. In order to cover with a molecule, a pre-coating layer having conductivity is formed in advance on the surface of the dielectric layer, which is an insulator, and then an electrode for electrolytic oxidation polymerization is brought into contact with the surface of the pre-coating layer to become a conductive polymer by polymerization. A method has been adopted in which a solution containing a monomer is introduced, a conductive polymer layer is polymerized and formed on the entire dielectric surface using the precoat layer as an anode, and then the electrode for electrolytic oxidation polymerization is removed. When using the chemical oxidation polymerization method, a method has been adopted in which a monomer and an oxidizing agent capable of oxidatively polymerizing the monomer are brought into contact on a dielectric film to form a conductive polymer layer on the entire dielectric surface. .

When the cathode electrolyte is solid, a carbon paste layer or a silver paste layer is interposed in order to join the formed solid electrolyte layer (manganese dioxide layer or conductive polymer layer) to the cathode current collector metal. A way to make it happen has been taken. The current collector metal for the cathode is arranged so as to be close to the outer shape of the valve metal porous body. For example, in the case of a multilayer aluminum electrolytic capacitor, as shown in FIG. A method of disposing them so that they are close to each other is disclosed in JP-A-6-168855. Further, a current collector for a cathode may be arranged for each of the stacked porous bodies. Japanese Patent Application Laid-Open No. 4-306427 discloses a method for producing an electrolytic capacitor in which a current collector metal for a cathode is directly bonded to a conductive polymer layer.

[0007]

However, in any of the electrolytic capacitors having the above-described structures, even if a conductive polymer having good conductivity is used as the cathode, the impedance cannot be sufficiently reduced, and the high-frequency response is poor. There was a problem that it was low. One of the reasons is that various layers are interposed in order to join the collector metal for the cathode and the conductive polymer. One is that the surface area of the cathode current collector metal is so small that the interface contact resistance cannot be reduced. In addition, a natural oxide film is formed on the surface of the current collector metal for the cathode,
In some cases, the contact resistance at the interface was increased.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide an electrolytic capacitor which has a low resistance at a junction between a cathode current collector metal and a conductive polymer, has improved impedance characteristics, and has excellent high-frequency response. To provide.

[0009]

In order to achieve the above object, an electrolytic capacitor according to the present invention comprises a dielectric oxide film formed on a valve metal porous body as an anode and formed on the entire surface of the valve metal porous body and the surface of pores. A conductive polymer layer as a cathode formed on the dielectric oxide film, a current collector for the anode electrically connected to a metal part inside the dielectric oxide film formed on the surface, and a cathode conductive material. In an electrolytic capacitor comprising a polymer layer and a cathode current collector electrically joined, the cathode current collector is a metal plate or foil, and at least the surface is roughened, or the surface has carbon particles. Embedded, or a carbon thin film layer is formed on the surface,
It is physically directly bonded to the conductive polymer layer.

With this configuration, the current collector for the cathode can be formed on the conductive polymer layer without interposing various intermediate layers (paste layers of carbon, silver, etc.) between the current collector for the cathode and the conductive polymer layer. It is intended to reduce the contact resistance of the interface between the current collector metal for the cathode and the conductive polymer layer by bonding, thereby reducing the impedance as a whole.

[0011] The electrolytic capacitor of the present invention includes those in which the negative electrode current collector has an elastic rubber or plastic film on the side opposite to the surface facing the valve metal porous body. Thereby, stress and the like after the formation of the conductive polymer can be reduced, and a highly reliable capacitor with few short circuits can be provided.

Further, the electrolytic capacitor of the present invention includes one in which the metal current collector for the cathode is formed by laminating a metal thin film on a plastic film. As a result, the impedance can be reduced, and in the event that a short circuit occurs, the metal thin film at the short-circuit location disappears, and the effect of recovering the characteristics can be obtained. Such a structure in which a unit in which such a cathode current collector is disposed so as to face both surfaces of the anode valve metal foil is laminated or wound is included. This is to improve the capacity per unit volume while reducing the impedance.

Further, the electrolytic capacitor of the present invention includes one in which the current collector for the cathode is a part of the capacitor element storage case. Thereby, the size of the capacitor can be reduced. Furthermore, in the electrolytic capacitor of the present invention, the anode valve metal porous body is a porous valve metal foil, and the cathode current collector is disposed so as to face one or both surfaces of the valve metal foil, and is laminated or wound. Including what is being turned. This is to further reduce the impedance by disposing the current collector for the cathode in close proximity to the anode valve metal foil, in addition to the above effects.

Further, in the electrolytic capacitor of the present invention, a foil or a plate having a large number of holes through which a current collector for a cathode penetrates on both sides is preferably used. When the porous body for anode is a valve metal foil, a foil having a large number of holes penetrating from front to back is also preferably used as the anode valve metal foil. In each case, the bonding property between the conductive polymer layer and the cathode current collector and the bonding property between the conductive polymer layer and the anode foil can be improved, and a highly reliable capacitor can be provided.

The manufacturing method for providing the above-mentioned electrolytic capacitor includes a step of forming a dielectric oxide film on the entire surface of the porous body made of valve metal and the entire surface of the pores, and a step of roughening the surface of the porous body. Alternatively, the method comprises a step of attaching to a current collector metal sheet (plate or foil) for cathode having carbon formed on the surface, and a step of forming a conductive polymer layer on a dielectric film.

Here, the present invention includes a case where the porous body made of a valve metal has a foil shape or a block shape (including a laminated type and a wound type).

After the cathode current collector is attached to the valve metal porous body, a conductive polymer layer is formed so that the gap between the cathode current collector and the dielectric oxide film can be filled with a conductive polymer. it can. Further, it can also be obtained by attaching the valve metal porous body having the conductive polymer layer formed thereon to the cathode current collector.

Here, in the case where the conductive polymer layer is formed at least first after the cathode current collector is attached to the porous body, the conductive polymer layer is previously formed on the surface of the cathode current collector facing the porous body. Keep it. As a result, an effect of preventing occurrence of a short circuit at the time of attachment can be obtained.

In the method for manufacturing an electrolytic capacitor according to the present invention, after the step of attaching the porous valve metal body having the conductive polymer layer formed thereon to the current collector for the cathode, the step of attaching the porous body and the current collector for the cathode is performed. In addition, those having a step of filling a conductive polymer are also included. Thereby, the joining property between the current collector for the cathode and the conductive polymer formed on the valve metal porous body is improved, and the impedance can be reduced.

In the method for manufacturing an electrolytic capacitor according to the present invention, the cathode current collector is a roughened valve metal foil having an oxide film, and the valve metal anode foil and the cathode foil are separated by a separator. Laminating or winding into a structure, providing electrodes for electrolytic oxidation polymerization on the entire end surface perpendicular to both foils and the separator, and growing a conductive polymer layer from the electrodes inside the structure by electrolytic oxidation polymerization to form a porous structure And those filled with a conductive polymer inside the holes. This makes it possible to easily and uniformly form the conductive polymer layer by electrolytic oxidation polymerization.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION In the electrolytic capacitor of the present invention, the anode is a metal having a valve action, the dielectric layer is an oxide layer of a valve action metal, and the cathode is a conductive polymer layer. In the present invention, the anode has a large number of pores or pores communicating with the external surface inside, and the anode surface area is significantly increased. Preferably, tantalum or aluminum can be used as the valve metal.

The dielectric layer is a very thin oxide film formed on the surface of the anode including the surface of pores inside the porous body. The oxide film is preferably formed by a chemical conversion treatment in an electrolytic solution.

The conductive polymer layer is formed on the dielectric layer including the internal pores and serves as a cathode. The conductive polymer layer forming the cathode is a polymer layer in which a polymer itself polymerized from a monomer exhibits conductivity. Examples of such a conductive polymer include a polymer of a heterocyclic 5-membered ring compound. Used, pyrrole, thiophene, 3
-Polymers such as alkylthiophenes and isothianaphthenes are preferably used. Further, a polymer of a six-membered ring compound exhibiting conductivity, for example, polyparaphenylene, polyaniline, or polyparaphenylenevinylene can also be used.

The conductive polymer layer preferably contains a dopant in the conductive polymer in order to further increase the conductivity of the polymer layer and reduce the resistance. For example, an arylsulfonate ion such as alkylnaphthalenesulfonic acid and paratoluenesulfonic acid, or an arylphosphate ion can be used.

In the present invention, a sheet (plate or foil) mainly made of metal is used for the current collector for the cathode.
As the material of the cathode current collector, nickel, copper, stainless steel, and aluminum are preferably selected from metals having low specific resistance and low ion migration. As the current collector for the cathode, a metal sheet in which carbon particles are embedded in a surface in contact with the conductive polymer layer is particularly preferable, and a metal sheet in which carbon is formed in a surface layer can also be used. By the carbon particles or the carbon layer, the conductive polymer and the cathode current collector metal can be joined without passing through the natural oxide film layer of the metal, and the interface contact resistance between the conductive polymer layer and the cathode current collector can be reduced. An electrolytic capacitor having a low resistance and a high high-frequency response can be obtained.

The current collector for the cathode is preferably a metal sheet having a roughened surface or a porous metal sheet in contact with the conductive polymer layer, whereby the conductive polymer layer and the current collector for the cathode are preferably formed. The interface resistance with the body can be reduced, and the impedance can be further reduced. Preferably, as the cathode current collector, a porous metal sheet roughened by AC etching in an electrolytic solution can be employed.

The same effect can be obtained by using a metal thin film having the same structure as the above-mentioned metal sheet formed on a plastic film as the negative electrode current collector. The effect that the metal thin film at the short-circuit portion disappears and the characteristics are restored is also obtained.

Further, by providing the cathode current collector having a large number of holes penetrating from the front surface to the back surface, the joining between the conductive polymer layer and the cathode current collector becomes easy, and the joining property between the both is improved. An improved and highly reliable electrolytic capacitor can be provided. A metal net or a punching metal can also be used as the collector metal for a cathode having such a through hole.

In particular, when the conductive polymer layer is collectively formed by the chemical oxidation polymerization method after the anode valve metal porous body is first attached to the cathode current collector, the case where the conductive polymer layer is provided with a through-hole is more preferable. There is an advantage that the conductive polymer layer can be formed uniformly.

In the present invention, as a method for forming a polymer layer on a dielectric layer, a solution containing a monomer is introduced onto a dielectric oxide film, and the monomer is chemically oxidized and polymerized with a polymerizable oxidizing agent in the solution. Or a method in which a solution containing a monomer is introduced onto a dielectric film and formed in the solution by electrolytic oxidation polymerization. In addition, a method in which a soluble conductive polymer or a thermoplastic conductive polymer generated in advance is introduced onto the dielectric film is also adopted.

In the electrolytic capacitor of the present invention, a porous valve metal is used as an anode, a dielectric oxide film is formed on the entire surface of the valve metal and the entire surface of the pores, and a conductive film is formed as a cathode formed on the dielectric oxide film. Current collector for the anode electrically connected to the conductive polymer layer, the metal part inside the dielectric oxide film formed on the surface, and the current collector for the cathode electrically connected to the cathode conductive polymer layer Body, the cathode current collector has carbon at least on the surface of the surface in contact with the conductive polymer layer, or the surface is a roughened metal sheet, and the conductive polymer layer It is configured by physically directly joining the As a result, the metal foil for the cathode and the dielectric oxide film are directly bonded with a conductive polymer without interposing various bonding layers (such as a carbon paste layer and a silver paste layer), and the current collector metal for the cathode is connected to the metal foil for the cathode. Since the interfacial contact resistance with the conductive polymer layer was reduced, the overall impedance could be reduced. Further, since there are no various bonding layers, the volume efficiency is improved and the size is reduced.

(Embodiment 1) Specifically, as shown in FIG. 1 (A), a first electrolytic capacitor of the present invention comprises a porous valve metal body 1 formed by laminating or winding a porous valve metal foil. It is possible to use a metal sheet having an anode structure formed by turning and a roughened surface of the cathode current collector 2. Metal sheet
Alternatively, as shown in FIG.
2 embedded is used. The metal sheet is a metal sheet having a carbon thin film layer 23 formed on the surface as shown in FIG. This current collector is disposed so as to be orthogonal to the surface of the valve metal foil that forms a porous body.
In the electrolytic capacitor of the present invention, as shown in FIG. 1 (B), the valve metal porous body 4 is formed of a sintered body formed by sintering valve metal powder, and is disposed on the cathode current collector. Have been.

In both of these electrolytic capacitors, a conductive polymer is filled on a dielectric layer, and the cathode current collector and the surface of the dielectric layer are joined only by a conductive polymer layer. The contact resistance at the interface with the cathode current collector metal could be reduced, and the above effects were obtained. In particular, the value of the minimum impedance at a high frequency corresponding to the equivalent series resistance is set to about 2 in the conventional case having a carbon paste layer or a silver paste layer or in the case where the surface of the cathode current collector is not treated.
/ 3 was able to be reduced. Therefore, it was possible to provide an electrolytic capacitor having good high-frequency response.

Here, as shown in FIG. 1 (C), it is preferable that the cathode current collector is provided with an elastic rubber or plastic film on the side opposite to the surface facing the valve metal porous body. Thereby, stress and the like after the formation of the conductive polymer can be reduced, and a highly reliable capacitor with few short circuits can be provided. The short-circuit occurrence rate as a product can be reduced to about 1/2 of the related art.

More preferably, the negative electrode current collector may be a part of the capacitor element storage case. By using the current collector for the cathode directly as the outer case, the occupancy of the capacitor element in the case can be increased, and furthermore, a smaller and larger capacity can be achieved.

(Embodiment 2) As shown in FIG. 2, a second electrolytic capacitor of the present invention uses a porous valve metal foil 1 as an anode valve metal porous body and faces the valve metal foil. Current collector 2 having a roughened surface or having carbon on its surface as described above, and joining the dielectric oxide film of the valve metal foil and the current collector for the cathode via a conductive polymer layer Can be adopted.

Here, as the porous valve metal foil, an electrolytically etched aluminum foil or a sheet foil obtained by shaping a sheet of tantalum powder and then sintering it can be particularly preferably employed. In this structure, the current collector 2 for the cathode is disposed so as to be opposed to and close to the anode valve metal foil 1, so that the impedance as a whole can be reduced. By doing so, the value of the minimum impedance at high frequency equivalent to the equivalent series resistance is 以下 or less of the case where many bonding layers are interposed as in the past, and the case where the surface of the cathode current collector is not treated Can be reduced to 1/2 or less. Therefore, an electrolytic capacitor having excellent high-frequency response can be provided.

The electrolytic capacitor of the present invention shown in FIGS. 4A and 4B has a structure in which a porous valve metal foil is used as the anode valve metal porous body and the porous valve metal foil is laminated or wound. However, the cathode current collector foil 2 having a roughened surface or having carbon on its surface is disposed so as to face both surfaces of the valve metal foil 1, and a dielectric oxide film of the valve metal foil is provided. The structure is such that the current collector for the cathode is joined via the conductive polymer layer 3. Also in this case, the effect of reducing the impedance can be obtained similarly to the above-mentioned foil type electrolytic capacitor.

Further, the electrolytic capacitor of the present invention has the structure shown in FIG.
As shown in (A), a porous valve metal foil is used as the valve metal porous body for the anode, and one sheet of the cathode current collector 2 having a roughened surface or having carbon on the surface layer is formed of two pieces. A structure in which a sheet of the valve metal foil 1 is sandwiched and the valve metal foil 1 and the current collector 2 for the cathode are joined via the conductive polymer layer 3 is referred to as an electrolytic capacitor unit. By adopting a structure in which a plurality of these units are stacked or wound, it is possible to achieve a lower impedance than in the conventional product and to increase the capacity per volume.

In this case, it is necessary to collect the current from the surface of the anode foil not facing the current collector for the cathode, so that the porous foil for the anode preferably has a through hole.

The current collector for the cathode is preferably formed by laminating a metal sheet thin film on a plastic film. Thus, in the event that a short circuit occurs, the metal thin film at the short-circuit location disappears, and the effect of recovering the characteristics can be obtained.

When the valve metal foil for the anode and the current collector for the cathode are opposed to each other with a separator interposed therebetween, a good electrolytic capacitor having a small leakage current can be obtained.

(Embodiment 3) An electrolytic capacitor according to a third embodiment of the present invention uses a porous valve metal foil as a valve metal porous body for an anode and a dielectric oxide film of the same kind as a current collector for a cathode. Using the formed porous valve metal foil to make it non-polar, a structure in which both foils are laminated or wound via a separator, and a conductive polymer layer formed by an electrolytic oxidation polymerization method And

Alternatively, the electrolytic capacitor of the present invention uses a porous valve metal foil as the anode valve metal porous body, and forms a roughened valve metal foil which has been subjected to a chemical conversion treatment at a voltage of 1 to 5 V as the cathode current collector. To form a structure in which an anode foil and a cathode foil are laminated or wound via a separator, and the conductive polymer layer is a conductive polymer layer formed by an electrolytic oxidation polymerization method.

These electrolytic capacitors are similar in shape to conventional solution-type wound electrolytic capacitors, but have the effect of reducing impedance compared to conventional electrolytic capacitors. Further, since a valve metal having an oxide film is used for the cathode, an effect of uniformly forming the conductive polymer when the conductive polymer is grown from the electrode for electrolytic oxidation polymerization can be obtained. The cathode current collector preferably has a large number of holes penetrating from the front surface to the back surface.

Also in the electrolytic capacitors of Embodiments 2 and 3, it is preferable that the porous valve metal foil for anode is a foil having many holes penetrating from the front surface to the back surface of the foil. Thus, the joining of the cathode foil and the anode foil with the conductive polymer layer is facilitated, the joining property between them is improved, and a highly reliable electrolytic capacitor can be stably manufactured and provided. In order to realize the above-described electrolytic capacitor, the electrolytic capacitor can be manufactured by using various manufacturing methods described below. Here, the type of valve metal is preferably tantalum or aluminum.

(Embodiment 4) A method for manufacturing an electrolytic capacitor will be described below. Here, the case where the anode porous body is a structure formed from valve metal foil, an anode structure formed by sintering valve metal powder, or a porous valve metal foil will be described.

In the first production method, after a dielectric oxide film is formed on the entire surface of the porous body made of valve metal and the entire surface of the pores, at least the surface that comes into contact with the conductive polymer layer is roughened. A plate-shaped or foil-shaped cathode current collector having carbon or having carbon on its surface is attached so as to be fixed in a predetermined positional relationship. Thereafter, the porous body with the current collector is immersed in a solution containing a monomer that becomes a conductive polymer by polymerization, the current collector for the cathode is used as an anode for electrolytic oxidation polymerization, and another electrode arranged in the solution is used as a cathode. , And a current flows during that. The current is adjusted to flow through the solution in the pores of the porous body. This current causes the monomer to be oxidized and polymerized on the cathode current collector, and directly grows as a conductive polymer layer. Since the generated conductive polymer itself conducts electricity, the monomer is oxidized and polymerized at the growth tip of the generated polymer, so that the conductive polymer is continuously formed in the pores inside the valve metal porous body. A layer is formed.
Thereby, the dielectric layer inside the valve metal porous body and the current collector for the cathode can be directly joined by the conductive polymer, and the electrolytic capacitor of the present invention can be manufactured.

In the present invention, it is important to efficiently supply an electric current to the monomer solution in the pores communicating with the porous body. To this end, a polymerization cathode in the solution is connected to a current collector for the cathode. It is preferable that at least the outer surface of the current collector is insulated and current flows only through the inside of the porous body, in opposition to the porous body side to which the body (polymerization anode) is attached. Whether the valve metal porous body is a sintered block, a foil laminate or a wound body, or even a foil shape can be handled similarly. In the case of a united block, as shown in FIGS. 6A and 6B, the cathode current collector 2 is placed on the inner bottom of an insulating, for example, synthetic resin or ceramic case 7. The porous polymer 4 is disposed inside the case, and is fixed to the case using the sealant 8 and the current is set to flow through the pores of the porous material, thereby forming the conductive polymer layer. Good.

In the case of an anode structure formed by laminating or winding a porous valve metal foil, for example, as shown in FIGS. 9 and 10, the cathode current collector is arranged perpendicular to the valve metal foil. It is preferable that the conductive polymer layer can be easily formed on the entire porous body. in this case,
This case can be used as it is as an outer case for fixing the capacitor. As described above, by forming the cathode current collector as a part of the case accommodating the capacitor porous body, the occupancy of the capacitor porous body in the case can be increased, and a small size and large capacity can be achieved. . Here, if a thin conductive polymer layer is previously provided on the dielectric surface by a chemical oxidation polymerization method, the conductive polymer can be uniformly formed to the deep part of the pores and filled, and the capacitance appearance rate can be reduced. A high good capacitor can be obtained.

Here, if a conductive polymer layer is previously formed on at least the surface of the cathode current collector facing the porous body, short-circuit defects can be reduced. The preformed conductive polymer layer is preferably formed by an electrolytic oxidation polymerization method, whereby the conductive polymer layer can be uniformly and efficiently formed on the surface of the cathode current collector metal. Further, when the valve metal porous body is in the form of a foil, a short circuit failure can be further reduced by sandwiching the separator between the cathode current collector and the anode valve metal foil when attaching to the cathode current collector. it can. When the valve metal porous body has a foil shape, the unit to which the cathode current collector is attached may be laminated or wound after the formation of the conductive polymer layer.

In the second production method, after a dielectric oxide film was formed on the entire surface of the porous body made of valve metal and the entire surface of the pores, a conductive precoat layer was provided on the dielectric oxide film. The precoat layer may be a layer having conductivity formed on the entire dielectric oxide film. It may be a thin conductive polymer layer formed by a chemical oxidation polymerization method or a manganese dioxide layer formed by a thermal decomposition method. Next, the porous body is immersed in a solution containing a monomer that becomes a conductive polymer by polymerization, and a third electrode is brought into contact with the precoat layer, and passed through the third electrode so that the precoat layer becomes an anode for electrolytic oxidation polymerization. Apply current. As a result, a current could be passed through the solution in the pores in the porous body using the precoat layer as an anode, and a conductive polymer layer could be formed on the precoat layer by electrolytic oxidation polymerization. By attaching the porous body having the conductive polymer layer formed thereon to a plate-shaped or foil-shaped cathode current collector having at least a surface in contact with the conductive polymer layer or having carbon on its surface. Thus, the electrolytic capacitor of the present invention can be manufactured. At this time, whether the valve metal porous body is a sintered block, a laminate of foils or a wound body, or even a foil shape can be handled similarly. For foil,
A unit to which the cathode current collector is attached may be laminated or wound.

Preferably, after the porous body having the conductive polymer layer formed thereon is attached to the cathode current collector, the gap between the conductive polymer layer and the cathode current collector is further increased by a chemical oxidation polymerization method. It is preferred that the conductive polymer layer be used. Thereby, the joining property of the cathode current collector and the dielectric surface by the conductive polymer is improved, and the responsiveness at higher frequencies is further improved.

When a conductive polymer layer is formed on a porous body having a dielectric oxide film formed thereon, at least the outermost layer of the conductive polymer layer is a conductive polymer layer having flexibility (such as polythiophene). Accordingly, a method for improving the bonding property when a porous body is attached to the cathode current collector can also be preferably used.

Further, a conductive polymer layer is previously formed on at least the surface of the cathode current collector facing the porous body, and preferably, at least the outermost layer portion of the conductive polymer film has a flexible conductive layer. The effect of improving the bonding property between the current collector for the cathode and the surface of the dielectric was also obtained by using the polymer layer. This previously formed conductive polymer layer is preferably formed by the electrolytic oxidation polymerization method, as before.

The third manufacturing method is the same as the first method except that the method of forming the conductive polymer layer on the porous body is a method of forming a conductive polymer layer on a dielectric oxide film by a chemical oxidation polymerization method. The electrolytic capacitor of the present invention is manufactured in the same manner as in the method of manufacturing.

At this time, the chemical oxidative polymerization may be carried out by alternately immersing in a solution containing an oxidizing agent and a solution containing a monomer, as is generally performed. It may be carried out by immersion in the substrate. At this time, whether the valve metal porous body is a sintered block, a laminate of foils or a wound body, or even a foil shape can be handled similarly. In the case of foil, a unit to which a current collector for a cathode is attached may be laminated or wound.

Here, it is important that a conductive polymer film is formed in advance on at least the surface of the cathode current collector facing the porous body, and short-circuit failure can be reduced as described above. Further, when the valve metal porous body is in the form of a foil, a short circuit failure can be further reduced by sandwiching the separator between the cathode current collector and the anode valve metal foil when attaching to the cathode current collector. it can.

The fourth manufacturing method is the same as the second method except that the method of forming the conductive polymer layer on the porous body is a method of forming a conductive polymer layer on a dielectric oxide film by a chemical oxidation polymerization method. An electrolytic capacitor is obtained in the same manner as in the manufacturing method. At this time, the valve metal porous body can be handled in the same manner regardless of whether it is a sintered block, a foil laminate or a wound body, or even a foil. In the case of foil, a unit to which a current collector for a cathode is attached may be laminated or wound. Here, the method of chemical oxidation polymerization is not limited as described above.

Further, a method of further filling the gap between the conductive polymer layer and the current collector for the cathode can be preferably used as in the above case. Further, a method of softening the surface layer of the conductive polymer layer can also be preferably used.

In the fifth manufacturing method, the conductive polymer layer is formed by introducing a soluble conductive polymer or a thermoplastic conductive polymer onto the dielectric oxide film and forming the conductive polymer layer on the dielectric oxide film. An electrolytic capacitor is obtained in the same manner as in the first manufacturing method except that a method for forming a conductive polymer layer is used. At this time, the valve metal porous body can be handled in the same manner regardless of whether it is a sintered block, a foil laminate or a wound body, or even a foil. In the case of foil, a unit to which a current collector for a cathode is attached may be laminated or wound.

Also here, it is important to form a conductive polymer film in advance on at least the surface of the cathode current collector facing the porous body, and the same effect as described above can be obtained. Further, when the valve metal porous body is in the form of a foil, a short circuit failure can be further reduced by sandwiching the separator between the cathode current collector and the anode valve metal foil when attaching to the cathode current collector. it can.

In the sixth manufacturing method, the conductive polymer is formed by introducing a soluble conductive polymer or a thermoplastic conductive polymer onto the dielectric oxide film and forming the conductive polymer on the dielectric oxide film. An electrolytic capacitor of the present invention was manufactured in the same manner as in the second manufacturing method except that a method for forming a conductive polymer layer was used. Even at this time, the valve metal porous body may be a sintered block, a foil laminate or a wound body,
Furthermore, even a foil shape can be handled similarly.
In the case of foil, a unit to which a current collector for a cathode is attached may be laminated or wound. Further, a method of further filling the gap between the conductive polymer layer and the current collector for the cathode can be preferably used as in the case described above. Further, a method of softening the surface layer of the conductive polymer layer can also be preferably used.

In the above manufacturing method, the valve metal porous body may be an anode structure formed by laminating or winding a porous valve metal foil, or an anode structure formed by sintering valve metal powder. Further, a porous valve metal foil may be used. In the case where the valve metal porous body is an anode structure formed by laminating or winding a porous valve metal foil, the cathode current collector is preferably arranged perpendicular to the valve metal foil. The polymer path can be arranged as short as possible, and the impedance can be reduced.

(Embodiment 5) In the seventh manufacturing method of the present invention, the valve metal porous body for anode is a porous valve metal foil, and the current collector for cathode is subjected to a chemical conversion treatment at a voltage of 1 to 5 V. This is a method for producing an electrolytic capacitor which is a valve metal foil having a roughened surface, and has a structure in which an anode foil and a cathode foil are laminated or wound with a separator interposed therebetween.

First, a dielectric oxide film was formed on the surface of the porous valve metal foil for the anode and the entire surface of the pores. On the other hand, the cathode valve metal foil was subjected to a chemical treatment at a voltage of 1 to 5V. After that, both foils are laminated or wound via a separator,
For example, as shown in FIG. 11, electrodes 21 for electrolytic oxidation polymerization were attached to the entire end faces perpendicular to both foils and the separator. Thereafter, the valve metal porous structure with the electrode attached thereto is immersed in a solution containing a monomer that becomes a conductive polymer by polymerization, and the electrode attached with the electrode is attached in the same manner as in the first manufacturing method of the fourth embodiment. Was used as an anode for electrolytic oxidation polymerization, and a current was passed through the solution in the gap in the porous structure. As a result, the conductive polymer layer was grown by electrolytic oxidation polymerization, and the inside of the pores of the porous structure was filled with the conductive polymer, thereby producing the electrolytic capacitor of the present invention.

The eighth production method is characterized in that the anode valve metal porous body is a porous valve metal foil, and the cathode current collector is a porous valve metal foil on which a dielectric oxide film of the same type is formed. Is a method for producing a nonpolar electrolytic capacitor having a structure laminated or wound with a separator interposed therebetween. In this manufacturing method, first, after forming a dielectric oxide film on the entire surface of the porous valve metal foil and the surface of the pores, the valve metal foil on which the dielectric oxide film was formed was laminated or wound via a separator. . Thereafter, the electrolytic capacitor of the present invention was manufactured in the same manner as in the seventh manufacturing method.

When a wound type and a multilayer electrolytic capacitor are manufactured by using the seventh and eighth manufacturing methods,
Capacitors that can easily achieve bonding and integration with a conductive polymer layer between a dielectric layer and a cathode foil, provide low-impedance large-capacity capacitors, and prevent deterioration due to solvent evaporation, which is a drawback of liquid aluminum electrolytic capacitors Can be provided.

In the seventh and eighth manufacturing methods, preferably, a thin conductive polymer layer is preferably provided on the dielectric surface in advance by a chemical oxidation polymerization method. This allows
The conductive polymer can be uniformly formed to the deep part of the pores to be filled, and a good capacitor having a high capacitance appearance rate can be obtained.

In the present invention, a part as an electrolytic capacitor is provided by electrically joining a metal part inside a dielectric oxide film formed on the surface of a valve metal porous body and an anode current collector. However, in some cases, furthermore, by electrically joining the anode current collector and the anode external electrode outside the case, and the cathode current collector and the cathode external electrode outside the case, an electrolytic capacitor can be formed. Parts can be provided.

[0071]

(Embodiment 1) This embodiment relates to the production of a polar tantalum electrolytic capacitor. First, tantalum powder is compression-molded with a lead wire attached thereto, and then fired in a high vacuum to produce a porous tantalum body. A capacitor element was produced.

Prior to forming a polypyrrole as a conductive polymer as a cathode on a chemical conversion treated porous element, the tantalum electrolytic capacitor of the present invention first has a case 7 having an inner surface rectangular as shown in FIG. A nickel plate in which carbon particles having a diameter of 5 μm were embedded by pressure bonding on one surface was disposed as a negative electrode current collector 2 on the bottom 70 so that a surface having carbon was opposite to the bottom 70.

A polypyrrole containing an arylnaphthalenesulfonate ion as a dopant is previously deposited on the carbon-containing surface of the cathode current collector 2 by electrolytic oxidative polymerization to form a dense conductive material having a thickness of about 20 μm. The conductive polymer layer 3 was formed. The porous element 4 of the tantalum sintered body is placed on the conductive polymer layer 3 on the cathode current collector 2, and the gap between the outer surface of the element 4 and the side surface 71 of the case 7 is sealed with a synthetic resin adhesive. The element 4 was sealed with a stopper 8, and the side surface of the element 4 was shielded.

Next, a mixed solution of propylene carbonate and alcohol containing pyrrole as a monomer for polymerization and arylnaphthalenesulfonate ion as a dopant is prepared, and as shown in FIG. After immersing the porous tantalum element 4 and impregnating the pores of the porous tantalum element 4 with the solution, the current collector 2 for the cathode is used as an anode, and between the platinum electrode as the counter electrode 10 arranged in the liquid 90. Then, a conductive polypyrrole layer was further polymerized 9 on the conductive polymer layer 3 previously formed on the cathode current collector 2. The polypyrrole layer formed by electrolytic oxidation polymerization joined the current collector 2 for the cathode and the porous element 4 of the capacitor, and filled the pores inside the porous body to form the cathode of the tantalum electrolytic capacitor. afterwards,
The upper surface of the porous body (the side opposite to the cathode current collector 2) was sealed with a resin plate using an epoxy resin adhesive to produce a polar tantalum electrolytic capacitor.

As Comparative Example 1, a porous element which had been subjected to a chemical conversion treatment at the same time as a conventional tantalum electrolytic capacitor,
By repeating the manganese nitrate pyrolysis method as before, a manganese dioxide electrolyte layer is formed from the inside of the device to the surface, then a carbon paste is applied to the surface, a silver paste is applied thereon, and bonding with the cathode lead is performed. And then coated with an exterior resin to produce a conventional tantalum electrolytic capacitor.

As Comparative Example 2, as a conventional tantalum electrolytic capacitor using a conductive polymer as a cathode, a porous element, which had been subjected to a chemical conversion treatment at the same time, was treated with a solution containing a monomer and a solution containing an oxidizing agent. After forming a conductive polymer layer using a general chemical oxidation polymerization method of alternately immersing the porous element in the surface, a carbon paste is applied to the surface, a silver paste is applied thereon, and a cathode lead and And then coated with an exterior resin to produce a conventional tantalum electrolytic capacitor. As Comparative Example 3, an electrolytic capacitor was produced in the same manner as in Example 1 except that no carbon was interposed in the nickel plate and the current collector for the cathode was used.

The frequency characteristics of the capacitance and the impedance at 120 Hz were measured for each of the tantalum electrolytic capacitors manufactured as described above. FIG. 8 shows the impedance measurement results.

The measurement results of the capacitance are about 95 μF for the manganese dioxide electrolyte product and the conductive polymer product according to the conventional method.
However, the electrolytic oxidation polymerization product had a capacity of 73 μF, and the capacity achievement ratio was poor. However, as shown in FIG. 8, the impedance was improved, and particularly, the impedance at the resonance point was reduced to の of the manganese dioxide electrolyte product and ／ of the conventional conductive polymer product. In addition, compared to the case where no carbon was interposed on the metal surface of the cathode current collector, about 2
/ 3.

In this embodiment, as the metal current collector for the cathode,
An example is shown in which carbon particles are compressed and embedded on the surface.However, even if a carbon thin film layer is formed on the surface or the surface is roughened, the interface contact resistance is similarly reduced and low impedance Could be achieved. (Example 2) As in Example 1, the present invention relates to the production of a polar tantalum electrolytic capacitor. In this example, an electroconductive polymer polypyrrole was preliminarily prepared by chemical oxidation polymerization in a tantalum element subjected to a chemical conversion treatment. This polypyrrole was synthesized as follows. First, add isopropyl alcohol to 1
Pyrrole was dissolved in an aqueous solution containing 0 vol% to a concentration of 0.1 mol / l to prepare a monomer solution. In an aqueous solution containing 10 vol% of isopropyl alcohol, iron (III) sulfate was dissolved at a concentration of 0.1 mol / l to prepare an oxidizing agent solution. The monomer solution and the oxidizing agent solution are mixed, and the capacitor element is immersed in the mixed solution to perform chemical oxidative polymerization, and polypyrrole containing no organic oxygen dopant is formed inside the pores of the capacitor element and on the element surface. It was formed on a dielectric layer.

Using the sample prepared as described above, polypyrrole was produced by electrolytic oxidation polymerization in the same manner as in Example 1 to produce a capacitor. As a result, other characteristics are the same as those of the polypyrrole product of Example 1, and only the capacity is 96 μF.
And improved. That is, a capacitor equivalent in capacity to a conventional tantalum electrolytic capacitor was obtained, and a capacitor having low impedance and good high-frequency response was obtained.

The conventional 10 μV 100 μF tantalum electrolytic capacitor having a carbon paste layer and a silver paste layer has a D size (88 mm 3).
The size of 100μF for 0V is 4.5mm × 3.2mm ×
3.0 mm (43 mm ³ ), about 1 /
2 volumes.

(Embodiment 3) As in Embodiment 1, the present invention relates to the production of a polar tantalum electrolytic capacitor. In this example, a conductive polymer polypyrrole was formed by chemical oxidation polymerization inside a chemical conversion-treated tantalum element. This polypyrrole was synthesized as follows.

First, isopropyl alcohol was added to 10 vol.
Pyrrole was dissolved in an aqueous solution containing 1% to a concentration of 1.0 mol / l to prepare a monomer solution. Arylnaphthalenesulfonate ion as a dopant was added to the monomer solution. Also, add isopropyl alcohol to 10
vol.% aqueous solution containing 0.1 m of iron (III) sulfate
ol / l to obtain an oxidizing agent solution. The tantalum element was alternately immersed in the monomer solution and the oxidant solution, and the monomer was polymerized by contact of the monomer and the oxidant. As a result, polypyrrole formed by the chemical oxidation polymerization method was formed inside the pores of the capacitor element and on the dielectric layer on the element surface and was filled.

The sample prepared as described above was placed on a Ni net as a cathode current collector having a carbon layer baked on the surface, and immersed in a solution containing a pyrrole monomer. Next, polypyrrole was formed on the cathode current collector by chemical oxygen polymerization, and a gap between the sample and the cathode current collector was filled with a conductive polymer and joined. As a result, Example 2
Thus, an electrolytic capacitor having the same capacitance and impedance characteristics as in Example 1 was obtained.

In this embodiment, the conductive polymer layer was formed and filled in the porous pores by the chemical oxidation polymerization method.
Even when using a commonly used electrolytic oxidation polymerization method,
Further, it goes without saying that the same effect can be obtained even when the soluble and thermoplastic conductive polymers are satisfied. Here, as shown in FIG. 1 (C), when a material provided with an elastic rubber or plastic film on the surface located on the side opposite to the porous material is used as a cathode current collector, Was able to relieve stress. As a result, when an electrolytic capacitor was used, the short-circuit occurrence rate without rubber or film was about 1%, whereas the short-circuit occurrence rate with rubber or film was 0%.

(Embodiment 4) This embodiment relates to the production of a polar aluminum electrolytic capacitor. AC etched 100 μm as porous valve metal foil 1
As shown in FIG. 9, a porous aluminum capacitor element having a valve metal laminated porous body 4 is produced by laminating thick low-voltage aluminum-etched foils and pressing them together with an aluminum metal plate 11 to which lead wires 12 are attached. did.

This device was placed in a phosphoric acid-based aqueous solution at 30 V
After a chemical conversion treatment at a voltage of 5 μm, a thin chemically oxidized polymer film of polypyrrole was formed on the dielectric layer inside and on the surface of the device as in Example 2.

Next, as shown in FIG. 10, a nickel plate cathode current collector 2 having one surface roughened by sandblasting is placed on the inner surface of the case 7 with the rough surface facing up, and electrolytic oxidation is performed thereon. Polypyrrole is formed by polymerization, and polythiophene having further flexibility is formed thereon to obtain a polypyrrole and a conductive polymer layer 3. On this, the capacitor element 4 is placed with the lamination surface perpendicular to the bottom surface of the case 7. The gap between the element 4 and the case 7 was sealed with a sealant 8. Next, in the same manner as in Example 1, the polypyrrole layer was polymerized and grown 9 to produce an electrolytic capacitor having a capacitance of about 70 μF. As shown in FIG. 10, the direction of the electrolytic oxidation polymerization is to form the electrolytic oxidation polymerization film in a direction perpendicular to the lamination direction, that is, in parallel with the lamination plane, in order to secure a path for flowing a current and diffusing the monomer. went. As a result,
The capacitance was 71 μF on average, and the impedance at the resonance point was as good as about 30 mΩ. Further, the surface roughening of the cathode current collector surface is caused by an increase in the surface area ratio due to the surface roughening to an apparent area of 3
More than twice, low impedance was achieved.

(Embodiment 5) This embodiment relates to the production of a polar aluminum electrolytic capacitor. In particular, the anode valve metal porous body is made of a porous foil, and the cathode current collector faces the anode foil. The present invention relates to the production of an electrolytic capacitor arranged as described above.

The AC-etched low-voltage aluminum etched foil having a thickness of 100 μm was subjected to a chemical conversion treatment in a phosphoric acid-based aqueous solution at a voltage of 15 V to form a dielectric film layer. The aluminum foil after chemical conversion is treated with a thiophene monomer 0.5
mol / l and iron (III) paratoluenesulfonate 1m
The solution was impregnated by immersion in an alcohol solution (polymerization solution) containing ol / l, then raised to the atmosphere and heated to 60 ° C. to polymerize the conductive polymer. These immersion, impregnation, and reaction operations were repeated 10 times to form a conductive polymer layer on the surface of the aluminum foil dielectric. The aluminum foil having the conductive polymer layer formed thereon and a porous pyrrole-based conductive polymer film formed on both surfaces in advance by an electrolytic polymerization method were made porous by AC etching as a current collector for a cathode.
After stacking the m-thick Ni foils so that they face each other, the foils are immersed again in the same polymerization solution as above, and the solution is impregnated between both foils.
A heating reaction was performed to form a thiophene-based conductive polymer between both foils. This operation was also repeated five times. Five electrolytic capacitor units formed by the above operation were laminated, and the aluminum metal portion for drawing out the anode was crimped. Then, the anode aluminum metal and the Ni foil for the cathode were drawn out and molded with resin. Thereafter, external electrodes were formed so as to be electrically connected to the extracted electrodes, thereby forming an electrolytic capacitor.

For comparison, as a conventional example, only an aluminum foil on which a conductive polymer layer had been formed was prepared.
Then, the conductive polymer layer was formed again to integrate the entire cathode. Thereafter, as shown in FIG. 13, a carbon paste layer and an Ag paste layer (conductor layer 13) for extracting the cathode were formed on the outer periphery of the cathode of the laminated structure, and joined to the cathode terminal. The anode was caulked with an aluminum metal part for drawing. Next, the cathode terminal and the anode aluminum were pulled out and molded into a resin, and external electrodes were formed so as to be electrically connected to the drawn-out electrodes, thereby forming an electrolytic capacitor. In this example, the outer dimensions of one aluminum foil were set to 3.3 mm × 3.7 mm in each case of the electrolytic capacitors.

In order to evaluate the high-frequency response of each of the manufactured electrolytic capacitors, a capacitance extraction ratio at a high frequency with respect to a low frequency and an impedance at a high frequency corresponding to an equivalent series resistance were measured.

Each of the manufactured electrolytic capacitors had a 120H
All capacitances at z were about 50 μF. However, the capacity at 100 kHz was 12 μF (capacity extraction rate: 24%) in the conventional electrolytic capacitor, whereas it was 47 μF (capacity extraction rate: 94%) in the electrolytic capacitor of the present invention. The impedance at 400 kHz was 30 mΩ in the conventional electrolytic capacitor, but was 10 mΩ in the electrolytic capacitor of the present invention. As another comparative example, the impedance at 400 kHz was 20 m for an electrolytic capacitor manufactured in the same manner as in Example 5 except that the Ni foil was not etched.
Ω. As described above, according to the present invention, it has been confirmed that the impedance can be reduced particularly at a high frequency and the capacity extraction rate can be improved.

In the embodiments of the present invention, the conductive polymer was formed by the chemical oxidation polymerization method. However, the same effect can be obtained by any of the various forming methods. Needless to say.

Also, in this embodiment, after forming the conductive polymer layer first, the valve metal anode foil having the conductive polymer formed thereon and the current collector for the cathode are arranged at predetermined positions, and between them. The conductive polymer layer was further filled, but after disposing the anode foil and the cathode current collector without the conductive polymer layer in place, the conductive polymer layer was put together between them and over the entire dielectric film. A similar effect was obtained even if a conductive polymer layer was formed on the substrate. At this time, the anode foil and the cathode current collector preferably had through holes.

In the embodiment of the present invention, the Ni foil roughened by etching is used as the cathode current collector. However, a porous aluminum foil obtained by AC etching in an electrolytic solution may be used. Nickel, copper, stainless steel,
Similar effects were obtained by using a foil in which carbon particles or carbon fibers were embedded in an aluminum metal foil or a foil in which a carbon layer was formed on the surface of various metal foils. Further, it was confirmed that the use of the penetrating foil could prevent the conductive polymer layer from peeling off from the metal foil, thereby improving the reliability. In this example, a thiophene-based monomer was used as a monomer, but the type of the polymer is not limited as long as the polymer has conductivity.

In this example, paratoluenesulfonate ions were used as dopants. However, similar effects were obtained with other arylsulfonate ions or arylphosphate ions.

(Embodiment 6) The present invention also relates to the production of a polarized aluminum electrolytic capacitor. The AC-etched low-voltage aluminum etched foil having a thickness of 100 μm was subjected to a chemical conversion treatment in a phosphoric acid-based aqueous solution at a voltage of 15 V to form a dielectric film layer.

On the other hand, aluminum was vapor-deposited on both surfaces of a plastic film having a through hole, and carbon was vapor-deposited on the metal foil as a cathode current collector. A conductive polymer layer in which pyrrole and thiophene were laminated was formed. Next, the aluminum foil that has been chemically formed and the metal foil with a plastic for cathode formed with a conductive polymer are alternately laminated five by five, and the aluminum metal part for anode drawing is caulked, and the metal foil for cathode is also drawn in the drawing part. Fixed to be integrated.

Thereafter, isopropyl alcohol was added for 10 vo.
0.1 mol / l pyrrole in an aqueous solution containing
0.1 mol / l of iron (III) sulfate as an oxidizing agent, and alkylnaphthalenesulfonate ion as a dopant of Na
After impregnating the above laminate at 5 ° C. with a reaction solution in which 0.05 mol / l is dissolved in the form of salt, the reaction is promoted by heating, and the conductive polymer layer is formed on the surface of the dielectric and the metal for the cathode. Polymerization formed between the foil and the dielectric surface. Thereafter, the laminate on which the conductive polymer layer was formed was molded with a resin while leaving both electrode lead portions, and external electrodes were formed on each of the drawn electrodes to produce an electrolytic capacitor rated at 6.5V.

For comparison, an electrolytic capacitor was prepared in the same manner as above except that an aluminum foil having a through-hole was formed by depositing carbon as a metal foil for a cathode.

In this embodiment, the outer dimensions of one aluminum foil are 3.3 m in any electrolytic capacitor.
m × 3.7 mm. In order to evaluate the high-frequency response of each of the manufactured electrolytic capacitors, a capacitance extraction ratio at a high frequency with respect to a low frequency and an impedance at a high frequency corresponding to an equivalent series resistance were measured.

120H of each of the manufactured electrolytic capacitors
All capacitances at z were about 50 μF. Also, 10
The capacitance at 0 kHz was about 46 μF (capacity extraction rate about 90%). The impedance at 400 kHz was about 10 mΩ.

On the other hand, the reliability of each electrolytic capacitor is 1
When the acceleration was evaluated at a load of 2 V, an electrolytic capacitor using a metal thin film with a plastic as the cathode metal foil was 1
While the short-circuit failure at 000 hours was 0, the short-circuit failure was 1.5% when ordinary metal foil was used.

As described above, according to the present invention, it has been confirmed that the impedance can be reduced particularly at a high frequency and the high-frequency response can be improved. In addition, it was confirmed that high reliability could be ensured by using a metal thin film with a plastic film as the metal foil for the cathode.

Example 7 A 30V anode foil with an anode lead wire 12 attached via a separator and a 2V cathode foil attached with a cathode lead wire 14 were superposed and wound to form a general aluminum electrolytic cell. A 100 μF capacitor element having a capacitor structure was manufactured. In advance,
The inside of the pores of the entire device was thinly covered with chemically oxidized and polymerized polypyrrole. As shown in FIG. 11, a nickel metal plate as an electrode 21 for electrolytic oxidation polymerization was attached to the bottom surface of this element, and the whole was immersed in a polymerization solution containing a pyrrole monomer in the same manner as in Example 1 and attached to the bottom surface. By passing a current through a solution in the space of the device using nickel metal as an electrode for polymerization, the gap inside the device was filled with a conductive polymer layer by electrolytic oxidation polymerization.

This capacitor is 95 μF at 120 Hz,
It showed a capacitance of 93 μF at 1 kHz. Further, the impedance characteristic was improved as shown in FIG. 12, and in particular, a capacitor whose impedance at the resonance point was one digit lower than that of the conventional tantalum electrolytic capacitor was obtained.

In this embodiment, an example of a capacitor having anode and cathode polarities has been described in the same manner as a normal aluminum electrolytic capacitor. However, in order to make the capacitor nonpolar, an anode foil is used instead of a cathode foil. Although the capacity is reduced by half, it goes without saying that a low-impedance capacitor can also be obtained.

In this embodiment, an example of a wound-type capacitor is shown. However, anode foils and cathode foils are alternately laminated via a separator, and each anode foil and each cathode foil are electrically conductive. Similar characteristics can be obtained by using a polymer electrically connected structure.

[0110]

As described above, according to the present invention, a metal sheet having at least a surface in contact with the conductive polymer layer or having carbon formed on the surface is used as the cathode current collector. After forming a conductive polymer in advance on the surface of the current collector for the cathode facing the current collector layer, by directly connecting the surface of the current collector for the cathode and the surface of the dielectric layer with the conductive polymer, easily. In addition, it is possible to efficiently provide a small, low-impedance electrolytic capacitor. Alternatively, an element in which a conductive polymer is formed on the surface of the dielectric layer in advance is bonded to the current collector for the cathode with a conductive polymer, so that the surface of the dielectric layer and the current collector for the cathode are electrically conductive. It is possible to provide a small-sized, low-impedance electrolytic capacitor that can be directly connected with a polymer, and can be easily and efficiently provided. In addition, by using the current collector metal plate for the cathode directly as the outer case, the occupancy of the capacitor element in the case can be increased, and a small size and large capacity can be achieved. Further, according to the present invention, by disposing the current collector for the cathode in close proximity to the anode porous valve metal foil, to increase the current collection area,
Furthermore, the metal foil for the cathode and the dielectric oxide film can be directly bonded with a conductive polymer without using various bonding layers (carbon paste layer or silver paste layer), thereby reducing the impedance as a whole. be able to.

Further, by forming a metal thin film on a plastic film as a metal foil for a cathode disposed close to a metal foil for an anode porous valve, if a short circuit occurs, the metal thin film at the short-circuited portion is lost. However, the effect of recovering the characteristics can be obtained, and a highly reliable electrolytic capacitor can be provided.

Further, according to the present invention, electrodes for electrolytic oxidation polymerization are mounted on the entire surface perpendicular to the foil and the separator in the wound type and laminated electrolytic capacitors, and the conductive electrodes are formed by electrolytic oxidation polymerization directly from the mounted electrodes. By growing the polymer and further growing the conductive polymer inside the capacitor element, the space of the element can be easily filled with the conductive polymer, and a low impedance electrolytic capacitor can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view (A, B, C) showing a structure of an electrolytic capacitor including a valve metal porous body and a cathode current collector according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a structure of an electrolytic capacitor including a valve metal foil and a cathode current collector according to the embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view (A, B, C) showing the structure of a cathode current collector according to an embodiment of the present invention.

FIG. 4A is a schematic cross-sectional view showing an electrolytic capacitor unit structure including a valve metal foil and a current collector for a cathode according to another embodiment of the present invention, and a schematic diagram of a multilayer electrolytic capacitor in which units are stacked. Cross-sectional view (B).

FIG. 5 is a view similar to FIG. 4 according to another embodiment of the present invention.

FIG. 6 shows a case (A) for performing an electrolytic oxidation polymerization treatment according to an embodiment of the present invention and a cross-sectional view (B) of a tantalum element and a cathode current collector arranged in the case during the treatment.

FIG. 7 is a layout diagram showing a method for forming a conductive polymer when performing electrolytic oxidation polymerization treatment on a tantalum element in a case according to an embodiment of the present invention.

FIG. 8 is a graph showing impedance characteristics of the tantalum electrolytic capacitor according to the embodiment of the present invention.

FIG. 9 is a perspective view of a porous aluminum electrolytic capacitor element according to an embodiment of the present invention.

FIG. 10 is a sectional view showing a state in which a conductive polymer is formed on a porous aluminum electrolytic capacitor element in an example of the present invention.

FIG. 11 is a schematic view of an element of a wound electrolytic capacitor having a metal plate as a polymerization electrode attached to a bottom surface in an example of the present invention.

FIG. 12 is a diagram showing impedance characteristics of the aluminum electrolytic capacitor in the example of the present invention.

FIG. 13 is a schematic sectional view showing the structure of a conventional electrolytic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Porous valve metal foil 2 Current collector for cathode 3 Conductive polymer layer 4 Porous valve metal 5 Dielectric oxide film 6 Rubber or plastic film 22 Carbon particles 23 Carbon thin film layer

Claims (34)

[Claims] A dielectric oxide film formed on the entire surface of the valve metal porous material and the surface of the pores; a conductive polymer layer as a cathode formed on the dielectric oxide film; In an electrolytic capacitor comprising an anode metal current collector electrically joined to a metal part of a porous body and a cathode metal current collector joined to a conductive polymer layer, the cathode metal current collector is An electrolytic capacitor which is a metal sheet material having carbon particles or a film whose surface is roughened or made porous and / or whose surface is in contact with a conductive polymer. 2. The electrolytic capacitor according to claim 1, wherein the metal current collector for the cathode is made of nickel, copper, stainless steel or aluminum. 3. The electrolytic capacitor according to claim 1, wherein the cathode metal current collector is a sheet comprising a plastic film and a metal thin film formed on the plastic film. 4. The electrolytic capacitor according to claim 1, wherein the cathode metal current collector has a large number of through holes penetrating from front to back. 5. The electrolytic capacitor according to claim 4, wherein the metal current collector for the cathode is a metal net instead of the metal sheet. 6. The electrolytic capacitor according to claim 1, wherein the metal collector for the cathode is formed by attaching an elastic rubber or plastic film to a metal surface not in contact with the conductive polymer. 7. An anode valve metal porous body is formed by laminating or winding a porous valve metal foil, and a cathode metal current collector is arranged perpendicular to the plane direction of the integrated valve metal foil. The electrolytic capacitor according to claim 1. 8. The electrolytic cell according to claim 1, wherein the anode valve metal porous body is a sintered body of valve metal powder, and the cathode metal current collector is disposed close to an outer surface of the sintered body. Capacitors. 9. The cathode metal current collector is a part of a capacitor element storage case for housing a valve metal porous body.
Or the electrolytic capacitor of 8. 10. The electrolytic capacitor according to claim 1, wherein the anode valve metal porous body is a porous valve metal foil, and the cathode metal current collector is a foil facing the valve metal foil. 11. A porous valve metal foil as an anode valve metal porous body is laminated or wound, and a cathode metal current collector foil is disposed so as to face both surfaces of the porous valve metal foil. The electrolytic capacitor according to claim 10. 12. An electrolytic capacitor unit in which a porous valve metal foil serving as a valve metal porous body for an anode is disposed so as to face both surfaces of a metal current collector foil for a cathode, and is laminated or wound. The electrolytic capacitor as described. 13. The electrolytic capacitor according to claim 10, wherein the anode valve metal foil and the cathode metal current collector foil face each other with a separator interposed therebetween. 14. The porous valve metal foil for an anode is a sheet obtained by forming an aluminum foil or a tantalum powder etched in an electrolytic solution into a sheet and then sintering the sheet. , 11 and 12. 15. The electrolytic capacitor according to claim 1, wherein the anode porous valve metal foil has a large number of through holes on both sides of the foil. 16. A step of forming a dielectric oxide film on an anode porous body made of a valve metal, a step of forming a conductive polymer layer on at least a surface of the cathode metal current collector facing the porous body, Attaching the cathode metal current collector having the conductive polymer layer formed thereon to the body, and forming the conductive polymer layer on the porous dielectric film to which the cathode metal current collector is attached, and simultaneously forming the conductive polymer Bonding the metal current collector for the cathode and the porous body via the layer. 17. A step of forming a dielectric oxide film on a porous body for an anode made of a valve metal; a step of forming a conductive polymer layer on a porous dielectric film; Joining the porous current collector to the negative electrode current collector via the conductive polymer layer by attaching the current collector. 18. A step of forming a dielectric oxide film on a porous body for an anode made of a valve metal, a step of forming a conductive polymer layer on a porous dielectric film, and at least one of a metal current collector for a cathode Forming a conductive polymer layer on the surface facing the porous body, and bonding the cathode metal current collector and the porous body via the conductive polymer layer by attaching the cathode metal current collector to the porous body. And a method for producing an electrolytic capacitor. 19. The metal current collector for a cathode, wherein a metal surface in contact with the conductive polymer is roughened or made porous and / or
19. The method for manufacturing an electrolytic capacitor according to claim 16, wherein the surface is a metal sheet material having fixed carbon particles or a film. 20. The step of joining the metal collector for the cathode and the porous body, wherein the step of immersing the porous body having the current collector in a solution containing a monomer that becomes a conductive polymer by polymerization, and Only by providing a shield so that a current of ion conduction flows, a current flows through the solution only into the pores using the metal collector for the cathode as an electrode for electrolytic oxidation polymerization, and the conductive polymer layer is formed by electrolytic oxidation polymerization. Is grown from the surface of the metal current collector for the cathode into the porous pores.
A method for producing the electrolytic capacitor described in the above. 21. A conductive polymer layer is formed in advance by a chemical oxidation polymerization method on a dielectric oxide film formed on the surface of the valve metal porous body and the entire surface of the pores, and then the cathode metal current collector is electrolyzed. 21. The method for manufacturing an electrolytic capacitor according to claim 20, wherein a conductive polymer layer is grown from the surface of the cathode metal current collector by electrolytic oxidation polymerization as an electrode for oxidative polymerization to fill pores inside the porous body. 22. The electrolytic method according to claim 21, wherein the conductive polymer layer previously formed by the chemical oxidation polymerization method is formed by chemically oxidizing and polymerizing a monomer in a solution containing no organic acid-based dopant. Manufacturing method of capacitor. 23. The step of forming a conductive polymer layer on the dielectric film and simultaneously bonding the cathode metal current collector and the porous body through the conductive polymer layer by a chemical oxidation polymerization method. 17. The method for producing an electrolytic capacitor according to claim 16, further comprising a step of forming a conductive polymer on the film and in a gap between the cathode metal current collector and the porous body. 24. The step of forming a conductive polymer layer on the dielectric film and bonding the cathode metal current collector and the porous body through the conductive polymer layer simultaneously with the step of forming a conductive polymer layer on the dielectric film. A plastic conductive polymer is impregnated into the above-mentioned porous body with a current collector, on a dielectric oxide film, and
17. The method for producing an electrolytic capacitor according to claim 16, further comprising a step of forming a conductive polymer in a gap between the metal collector for the cathode and the porous body. 25. After the above step of attaching a metal current collector for a cathode to a porous body having a conductive polymer layer formed thereon,
19. The method for manufacturing an electrolytic capacitor according to claim 17, further comprising a step of filling a gap between the porous conductive polymer layer and the cathode metal current collector with the conductive polymer layer by a chemical oxidation polymerization method. 26. The electrolysis according to claim 17, wherein the conductive polymer layer formed on the porous body on which the dielectric oxide film is formed is a conductive polymer having at least the outermost layer portion of the conductive polymer layer having flexibility. Manufacturing method of capacitor. 27. The method for producing an electrolytic capacitor according to claim 16, wherein at least the outermost layer of the conductive polymer layer formed in advance on the surface of the cathode metal current collector is a flexible conductive polymer layer. 28. The method for manufacturing an electrolytic capacitor according to claim 16, wherein the conductive polymer layer previously formed on the surface of the metal current collector for the cathode is formed by electrolytic oxidation polymerization. 29. The anode valve metal porous body is formed by laminating or winding a porous valve metal foil, and is arranged perpendicularly to the valve metal foil on which the cathode metal current collector is integrated. Item 19. The method for manufacturing an electrolytic capacitor according to any one of Items 16, 17, and 18. 30. The method for producing an electrolytic capacitor according to claim 16, wherein the anode valve metal porous body is formed by sintering valve metal powder. 31. The method for producing an electrolytic capacitor according to claim 16, wherein the anode valve metal porous body is a porous valve metal foil. 32. A step of forming a dielectric oxide film on the surface of the anode porous valve metal foil and the entire surface of the pores, and forming a roughened cathode valve metal foil on a roughened surface at a voltage of 1 to 5V. Applying, laminating or winding both foils via a separator, attaching an electrode for electrolytic oxidation polymerization to the entire end surface perpendicular to both foils and the separator, and polymerizing a monomer that becomes a conductive polymer by polymerization. A step of immersing the valve metal porous structure with the electrodes attached thereto in a solution containing the electrodes, and passing an electric current through the solution in the gap in the porous structure using the attached electrodes as an anode for electrolytic oxidation polymerization, and conducting the cells by electrolytic oxidation polymerization. Growing a conductive polymer layer and filling the inside of the pores of the porous structure with a conductive polymer. 33. A step of forming a dielectric oxide film on the surface of the porous valve metal foil and the entire surface of the pores, and laminating or winding two valve metal foils on which the dielectric oxide film is formed via a separator. Process, and a process of attaching electrodes for electrolytic oxidation polymerization to the entire end face perpendicular to both foils and the separator,
A step of immersing the valve metal porous structure attached with the electrode in a solution containing a monomer that becomes a conductive polymer by polymerization,
The attached electrode is used as an anode for electrolytic oxidation polymerization, and a current is passed through the solution in the gap in the porous structure to grow a conductive polymer layer by electrolytic oxidation polymerization. A method for producing a non-polar electrolytic capacitor, the method comprising: 34. A method for forming a conductive polymer layer on a whole surface of a valve metal oxide film of a valve metal porous structure by a chemical oxidation polymerization method, and then growing the conductive polymer layer by electrolytic oxidation polymerization. The method for manufacturing an electrolytic capacitor according to claim 32 or 33, wherein the internal holes are filled.