JP2001196271A - Solid electrolytic capacitor and method of manufacturing the same - Google Patents

Abstract

[PROBLEMS] To reduce leakage current by aging a solid electrolytic capacitor more efficiently than aging relying on moisture absorption. In addition, the leakage current is reduced while suppressing a decrease in capacitance. SOLUTION: A capacitor element including a valve metal, an oxide film layer and a solid electrolyte layer has a boiling point of 150 ° C.
An organic compound having a melting point of 50 ° C. or less is contained, and the capacitor element is disposed inside the package with the organic compound included. The application of a DC voltage restores the oxide film using the organic compound as a solvent. Further, a substance having a reduction potential equal to or higher than the hydrogen generation potential is contained in the solid electrolyte layer together with (or instead of) the organic compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolytic capacitor using a valve metal such as aluminum, tantalum or niobium as an anode and a solid electrolyte such as a conductive polymer or manganese dioxide as an electrolyte and a method for producing the same. It is.

[0002]

2. Description of the Related Art A solid electrolytic capacitor using a valve metal as an anode is generally manufactured by the following method. First, a valve action metal porous body such as aluminum whose surface is roughened or powder sintered tantalum or niobium is used as an anode, and a dielectric oxide film is formed on the entire surface of the valve action metal porous body. Next, a conductive polymer such as polypyrrole or manganese dioxide is formed as a solid electrolyte layer on the surface of the dielectric oxide film. Subsequently, a cathode layer composed of a carbon layer, a silver layer, and the like is formed on the solid electrolyte layer. Thereafter, an anode lead terminal is attached to the anode lead portion by welding or the like, and a cathode lead terminal is attached to the cathode layer using a conductive adhesive or the like. Finally, so that a part of the cathode lead terminal and the anode lead terminal is exposed to the outside,
The entire device is covered with an exterior resin. In some cases, a method in which the cathode layer is not formed and a direct electrical connection is made from the solid electrolyte layer to the cathode extraction terminal.

[0003] Since the exterior resin plays a role of maintaining the airtightness with the outside, it is necessary to secure the adhesion strength between the exterior resin and an electrode lead member such as a lead, a foil or a terminal. In particular, when a conductive polymer is used for the solid electrolyte, if the airtightness is not sufficient, the deterioration will be severe, and it will be difficult to maintain the electrical characteristics for a long time. Therefore, in order to ensure airtightness, the exterior resin is generally formed by molding (chip type) or dip molding (lead wire type) using an epoxy-based thermosetting resin.

[0004] A solid electrolytic capacitor using a case instead of an exterior resin is also known. This capacitor is manufactured by inserting the whole element into a case and sealing the opening of the case with a resin or the like with a part of the cathode lead terminal and the anode lead terminal pulled out to the outside. As the case, an insulator of resin or ceramics, or a metal in which a joint with a terminal portion is insulated is used.

[0005]

Generally, an electrolytic capacitor using an electrolytic solution as an electrolyte has an ability to repair a defect generated in a dielectric oxide film during manufacturing. Therefore, the leakage current does not increase significantly. However, a solid electrolytic capacitor using a solid electrolyte as an electrolyte lacks the ability to repair a dielectric oxide film because the electrolyte is solid. Therefore, when a defect occurs in the dielectric oxide film, the defect cannot be self-repaired. Therefore, when the dielectric oxide film is deteriorated due to mechanical stress or thermal stress during manufacturing, the leakage current tends to increase.

Therefore, aging has conventionally been performed to reduce the leakage current of the solid electrolytic capacitor.
This aging treatment is performed by applying a predetermined DC voltage between the anode and cathode terminals before or after forming the outer package. In this process, the film is restored using water absorbed from the atmosphere as an electrolytic solution. However, since the repair depends on the moisture absorption of the element, the conventional aging process requires a long time to obtain stable leakage current characteristics.

[0007] Japanese Patent Application Laid-Open No. H5-243096 proposes a method in which, when a conductive polymer is used as a solid electrolyte, a current is concentrated in a portion where the breakdown voltage is reduced, and the conductive polymer is insulated by Joule heat. ing. However, when the defect is large, the insulation is insufficient, and the leakage current cannot be reduced in some cases.

[0008] The oxide film also deteriorates due to the formation of the solid electrolyte layer. Therefore, in the manufacturing process of the solid electrolytic capacitor, the film is repaired by re-chemical conversion. Re-chemical formation is performed by immersing the capacitor element on which the solid electrolyte is formed in an electrolytic solution, and applying a DC voltage between the electrolytic cell and the anode of the capacitor element using the electrolytic cell as a cathode. Re-chemical formation is an effective means for suppressing leakage current together with aging. However, when re-chemical formation or the like is performed, a phenomenon in which the capacitance of the capacitor decreases may be observed. Also, in the aging process, a phenomenon that the capacitance of the capacitor is reduced may be observed.

Accordingly, an object of the present invention is to provide a solid electrolytic capacitor capable of reducing a leakage current more efficiently than aging relying on moisture absorption and a method of manufacturing the same. Also,
It is another object of the present invention to provide a solid electrolytic capacitor capable of reducing a leakage current while suppressing a decrease in capacitance, and a method for manufacturing the same.

[0010]

To achieve the above object, a first solid electrolytic capacitor of the present invention comprises a valve metal, an oxide film layer formed on the surface of the valve metal, and an oxide film formed on the valve metal. A capacitor element including a solid electrolyte layer formed on the layer is provided inside the exterior body, and the capacitor element contains an organic compound having a boiling point of 150 ° C. or higher and a melting point of 150 ° C. or lower.

Further, a first method for manufacturing a solid electrolytic capacitor of the present invention is a method for manufacturing a capacitor as described above,
An organic compound having a boiling point of 50 ° C. or more and a melting point of 150 ° C. or less is impregnated into the inside of the capacitor element, and the capacitor element is placed inside the exterior body while containing the organic compound.

According to the first capacitor and the method for manufacturing the same, the solid electrolytic capacitor can be aged more efficiently than in the prior art due to the presence of the organic compound, and a solid electrolytic capacitor having a small leakage current can be easily obtained. Can be.

In order to achieve the above object, a second aspect of the present invention is provided.
A solid electrolytic capacitor having a valve element, an oxide film layer formed on the surface of the valve metal, and a capacitor element including a solid electrolyte layer formed on the oxide film layer inside an exterior body, The capacitor element contains a substance having a reduction potential equal to or higher than the hydrogen generation potential.

Further, a second method of manufacturing a solid electrolytic capacitor according to the present invention comprises a valve metal, an oxide film layer formed on the surface of the valve metal, and a solid electrolyte layer formed on the oxide film layer. And a substance having a reduction potential equal to or higher than the hydrogen generation potential is contained in the solid electrolyte layer before disposing the capacitor element inside the exterior body.

According to the second capacitor and the method of manufacturing the same, the presence of the substance having a reduction potential equal to or higher than the hydrogen generation potential can reduce the leakage current while suppressing a decrease in capacitance. The addition of the above substances is effective not only at the time of aging but also particularly at the time of re-chemical formation.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.

The organic compound contained in the capacitor element is
Since it has a high boiling point of 150 ° C. or more, it is difficult to vaporize even after heat treatment in a manufacturing process of a solid electrolytic capacitor or the like. In the manufacturing process of the solid electrolytic capacitor, the heat treatment for fixing the capacitor element to the lead-out terminal and forming the cathode layer often involves heating at least about 150 ° C. Therefore, when an organic compound having a boiling point of less than 150 ° C. is used, not only is it not retained even when impregnated, but also it vaporizes and causes poor formation of the cathode layer and the like and poor connection to the lead terminal, thereby deteriorating the electrical characteristics of the capacitor. There is.

The boiling point of the organic compound is more preferably 200 ° C. or higher. This is because, when the resin is formed by transfer molding or dip molding as the exterior body, the capacitor element is exposed to heating at about 150 to 200 ° C. to cure the resin.

The boiling point of the organic compound is particularly preferably 250 ° C. or higher. When a so-called chip-type solid electrolytic capacitor is mounted on a board by soldering, the capacitor may be 230 to 2
This is because they are exposed to heating at about 50 ° C. However,
Depending on conditions such as the mounting method and heating time, even if the boiling point of the organic compound is less than 250 ° C, it can withstand use without sudden vaporization, so the boiling point of the organic compound used for the capacitor to be soldered is 250 ° C or more. It is not limited to.

The organic compound has a melting point of 150 ° C. or less, and exists locally as a liquid. Even if it is a solid, it is locally rapidly generated by Joule heat due to a leakage current at an oxide film defect when a voltage is applied. May liquefy. Using this liquid as a solvent (organic solvent), ions are eluted from the solid electrolyte layer to form an electrolytic solution. Thus, the self-healing ability is provided to the capacitor element. When the self-healing ability is given, the oxide film defect generated in the manufacturing process can be easily repaired by the aging voltage, and even if a defect occurs in the oxide film during product mounting or use, the self-repair by applying the voltage during use Repair is possible.

The organic compound is preferably solid at room temperature (25 ° C.). Such an organic compound hardly exudes from the exterior body and has excellent holding properties. The melting point of the organic compound is preferably higher than 25 ° C. in order to be in a solid state at room temperature, and more preferably higher than 40 ° C. This is because it can exist as a solid in a normal use temperature range (40 ° C. or less) of an electric product including a solid electrolytic capacitor. In particular, when a resin is used as the exterior body, it is desired that the organic compound does not penetrate into the resin from the inside of the capacitor element and attack the resin in a normal use temperature range.
When a higher use temperature range is assumed, an organic compound having a melting point exceeding 60 ° C. may be used.

If the organic solvent has an excessive amount of ions, a sharp current flows through a defective portion of the oxide film when a voltage is applied, and the film may be damaged on the contrary. Therefore, the organic solvent is
A substance that does not substantially dissociate ions or has a low dissociation constant is preferred.

The organic compound capable of providing such an organic solvent is not particularly limited, and includes at least one selected from alcohol, phenol, ester, ether and ketone. Here, the terms from alcohol to ketone are used in a broad sense. For example, phenol includes various phenol derivatives in which hydrogen on a benzene ring is substituted with a hydroxyl group. These compounds generally provide an organic solvent that becomes an electrolyte having moderate conductivity by elution of ions from the solid electrolyte.

If the dissociation constant is not excessively high, an organic acid can be used as the organic compound. Fatty acids are preferred as such organic acids. Organic acid at 25 ° C
It preferably has a dissociation constant of 4.5 or more expressed by pKa. This is because conductivity appropriate for repair can be obtained by appropriate dissociation.

Another example of a suitable organic compound is an amine. Here, the term amine is a broad term including aliphatic amines and aromatic amines, and includes all primary to tertiary amines. The amine has a function of coordinating with hydrogen ions in the organic solvent to lower the hydrogen ion concentration. By this action, damage to the oxide film by the strong acid can be suppressed. In particular, when aluminum is used as the valve metal, an increase in the hydrogen ion concentration causes excessive damage to the oxide film. However, when an amine is used, this damage can be suppressed.

When the oxide film is repaired, the hydrogen ions are reduced by the paired reaction to generate hydrogen gas. In order to actively suppress the generation of hydrogen gas, it is preferable that the capacitor element further contain a substance having a reduction potential equal to or higher than the hydrogen generation potential, in other words, an oxidizing agent which is more easily reduced than hydrogen. This is because such a substance is preferentially reduced over hydrogen to suppress generation of hydrogen gas.

Examples of the substance having a reduction potential higher than the hydrogen generation potential include perchloric acid and its salts, permanganic acid and its salts, chromic acid and its salts, peroxodisulfuric acid and its salts, and nitro group-containing compounds. be able to. However, when a conductive polymer is used as the solid electrolyte, it is preferable to select a substance that does not oxidize and decompose the conductive polymer. Such substances include:
Compounds containing nitro groups are most suitable. This substance also
For the same reason as above, it is preferable to have a boiling point of 150 ° C. or higher.

The generation of hydrogen gas increases the internal pressure of the condenser. In particular, since the gas pressure increases between the solid electrolyte layer and the dielectric oxide film, if the internal pressure rises excessively, the solid electrolyte layer may peel off from the dielectric oxide film.
The peeling of the solid electrolyte layer causes a new problem that the capacitance of the capacitor decreases. In conventional aging, in which an oxide film is repaired with water that has absorbed moisture, generation of hydrogen gas due to reduction of hydrogen ions has been inevitable. However, according to the preferred embodiment of the present invention, the oxide film can be repaired while suppressing generation of hydrogen gas.

The above substances capable of suppressing the generation of hydrogen gas are also effective for maintaining the capacitance in the step of re-forming a solid electrolytic capacitor. The re-formation is performed in a solvent such as water or alcohol. For this reason, the generation of hydrogen gas due to the reduction of hydrogen ions becomes a problem as described above. In order to obtain stable leakage current characteristics, it is desirable to apply re-chemical formation each time the solid electrolytic layer is formed a plurality of times. The re-formation a plurality of times tends to lower the capacitance, but if the solid electrolyte contains a substance having a reduction potential higher than the hydrogen generation potential, the solid electrolyte layer can be prevented from peeling off.

That is, in a preferred embodiment of the production method of the present invention, before disposing the capacitor element inside the outer package, the solid electrolyte layer containing a substance having a reduction potential higher than the hydrogen generation potential or a solid electrolyte layer containing A step of repairing a defect in the oxide film layer is further performed by applying a DC voltage in a state where the solvent is in contact with the solid electrolyte to be a part. As a solvent to be an electrolytic solution, an organic solvent such as water and alcohol, or a mixed solvent thereof can be used.
The solid electrolyte layer may be formed by alternately repeating the step of forming a part of the solid electrolyte layer and the above-described step of repairing a defect of the oxide film layer.

The generation of hydrogen gas accompanying the repair of the oxide film will be described with reference to FIG.

When a voltage is applied to repair the defective portion 110 of the oxide film 102, the valve metal 1
The following reaction (1) proceeds on the 01 side (anode side), and the following reaction (2) proceeds on the solid electrolyte layer 103 side (cathode side) of the deficient portion 110 (FIG. 5A).
As a result, the repair part 112 of the oxide film is generated by the reaction (1), but the peeling 111 of the solid electrolyte layer may occur due to the pressure of the hydrogen gas generated by the reaction (2) (FIG. 5 (B)). )). Although the following reaction formula illustrates the case where tantalum is used as a valve action metal, the same reaction proceeds when another valve action metal is used.

2Ta + 10OH ⁻ → Ta ₂ O ₅ + 5H ₂ O + 10e ⁻ (1) 10H ⁺ + 10e ⁻ → 5H ₂ ↑ (2)

The above-mentioned substance added together with the organic compound or alone to suppress the separation of the solid electrolyte layer does not release gas (is not gasified) even when reduced, while suppressing the reaction (2). More preferably, it is a substance.

As the organic compound, a substance having a reduction potential higher than the hydrogen generation potential may be used. Examples of such a substance include 3-nitroanisole, a nitro group-containing compound (melting point: 54 ° C, boiling point: 260 ° C).

In order to provide a solid electrolytic capacitor with a self-healing ability by using an organic compound, it is necessary not only to include the organic compound in the capacitor element but also to make sure that the organic compound is not lost in the manufacturing process. There is. Conventionally, when a conductive polymer is used for a solid electrolyte layer, various organic compounds have been added as a polymerization accelerator or the like. However, since the conductive polymer layer is washed after formation, even if the added organic compound remains after polymerization of the conductive polymer, it has been washed away. Therefore, it is preferable that the organic compound is impregnated after the washing step of the solid electrolyte layer, or a cleaning liquid in which the organic compound is hardly dissolved is selected so that the organic compound is hardly washed off even if impregnated before the washing step. Thus, the capacitor element containing the organic compound can be housed in the case or covered with the exterior resin.

For effective repair, it is desired that the organic compound is impregnated deep into the pores of the capacitor element. In particular, the following method is suitable for deeply impregnating an organic compound which is solid at room temperature.

One example of the above method is a method including a step of impregnating a capacitor element with a solution in which an organic compound is dissolved in a solvent, and a step of heating to evaporate the solvent.
As the solvent, an organic solvent having a boiling point of 100 ° C. or lower is preferable. For example, lower alcohols such as ethanol and isopropyl alcohol can be used.

Another example of the above method is a method of impregnating a capacitor element with vapor generated by heating an organic compound.

Another example of the above method is a method of impregnating a capacitor element with an organic compound liquefied by heating.

Still another example of the above method is a method of impregnating a capacitor element with an organic compound whose viscosity has been reduced by heating.

Each of the above methods may be performed at any stage after forming the solid electrolyte layer and before disposing the capacitor element inside the exterior body.

Another example of the above method is a method in which an organic compound is added to a solution for forming a solid electrolyte layer so that the organic compound is contained in a capacitor element.

Each of the methods exemplified above may be appropriately selected according to the kind of the organic compound and the like. However, from the viewpoint of the degree of reaching the deep part of the pores, a method of evaporating and removing the solvent after the impregnation of the dissolved solution, and a method of containing the solvent at the time of forming the solid electrolyte layer are advantageous, and the effect is increased by increasing the impregnation concentration. From the viewpoint, a method using a vapor method, a liquefaction method, or the like is advantageous.

Using the organic compound impregnated in this way, the defect of the oxide film is repaired. That is, as described above, by applying a DC voltage, a step of repairing a defect of the oxide film layer that is in contact with the liquid of the organic compound is further performed. If the organic compound is solid at the time of this aging treatment, the organic compound is liquefied by the heat generated by current concentration on the defective portion with the application of the DC voltage, and the defect of the oxide film layer is repaired by the application of the DC voltage. Good to do.

Since the re-chemical formation can be performed in the step of forming the solid electrolyte layer, it is not necessary to consider the influence of the cleaning. Substances having a reduction potential equal to or higher than the hydrogen generation potential
For example, by adding to a solution for forming a solid electrolyte layer, it can be contained in the solid electrolyte layer.
Further, for example, the solution in which this substance is added can be contained in the solid electrolyte layer by contacting the solution with the solid electrolyte layer or a solid electrolyte that becomes a part of the solid electrolyte layer.

The substance having a reduction potential equal to or higher than the hydrogen generation potential is preferably contained in the solid electrolyte layer in a range of 50 ppm to 10% by weight. If the concentration is too low, the effect of suppressing the decrease in capacitance may not be sufficiently obtained. On the other hand, if the concentration is too high, the conductivity of the conductive polymer may be reduced. Note that, due to washing of the solid electrolyte layer after re-chemical formation, the above concentration may be measured as a value lower than the value at the time of re-chemical formation in a solid electrolytic capacitor as a final product.

Hereinafter, an example of the solid electrolytic capacitor of the present invention and a method of manufacturing the same will be described with reference to the drawings.

In the solid electrolytic capacitor shown in FIG. 2, the capacitor element is covered with an outer package 9. In this solid electrolytic capacitor, the capacitor elements include an anode 1 made of a valve metal, a dielectric oxide film 2 formed on the surface of the valve metal, a solid electrolyte layer 3 formed on the dielectric oxide film, and a solid electrolyte layer. It comprises a cathode layer 4 formed thereon.

The capacitor element is entirely covered by an outer package 9. However, in order to ensure conduction, the cathode lead-out terminal 7 and the anode lead-out terminal 8 are drawn out of the capacitor element through the exterior body 9. The anode lead-out terminal 8 is connected to the anode 1 via the anode lead 5. On the other hand, the cathode lead-out terminal 7 is connected to the cathode layer 4 via a conductive adhesive 6 or the like.

The solid electrolytic capacitor to which the present invention can be applied is not limited to the embodiment shown in FIG. 2. For example, as shown in FIG. 3, an anode exposed on the surface of the outer package 9 without an anode lead-out terminal is provided. A pair of external terminals 10 respectively connected to the lead 5 and the cathode lead terminal 7 may be arranged. Further, as shown in FIG. 4, the cathode lead-out terminal is also omitted, and the cathode foil 11 attached to the cathode layer 4 with the conductive adhesive 6 or the like is exposed on the surface of the exterior body 9. A pair of external terminals 10 may be connected to the leads 5 respectively. In these structures, the formation of the cathode layer 4 and the conductive adhesive 6 can be omitted. In addition, although not shown, a structure in which a solid electrolyte is filled in place of an electrolytic solution on a wound product of an anode foil, a cathode foil, and a separator, as in a conventional electrolytic solution type electrolytic capacitor, is employed. Is also good. In this case, each of the leads attached to the anode foil and the cathode foil is pulled out from the exterior body to become a terminal.

Hereinafter, each member will be further described.

The anode 1 is made of a valve metal. Aluminum, tantalum or niobium can preferably be used as valve metal. Although not shown, the anode is a porous body having a large number of fine holes or pores communicating with the outer surface.

When aluminum is used as the anode,
A porous body in which a number of small holes are formed by subjecting an aluminum foil to a surface roughening treatment such as an etching treatment may be used. When tantalum or niobium is used, a porous body obtained by pressing and molding a valve metal powder and then sintering may be used. The valve metal powder may be applied in the form of a sheet and then sintered to form a porous body. These porous foils may be wound or laminated.

The dielectric oxide film layer 2 is formed by anodizing the surface of the valve metal porous body. Although not shown here, the dielectric oxide film layer is usually formed on all surfaces of the valve metal except a part of the anode lead 5 for joining to the anode lead-out terminal. It is also formed on the surface of the hole.

The solid electrolyte layer 3 is formed from manganese dioxide or a conductive polymer material. Although not shown here, this layer is also formed in the fine pores of the porous body.
The solid electrolyte is not particularly limited, but a conductive polymer such as polypyrrole, polyaniline, and polythiophene is preferable.

The cathode layer 4 is composed of a carbon layer, a silver layer and the like, and is formed to collect the capacity drawn by the solid electrolyte layer. The cathode layer is formed on the foil surface when the anode valve-acting metal porous body has a foil shape. However, when using a rolled or laminated body of foil as the porous body,
It may be formed on the outer surface of the entire porous body. When the porous body is a powder sintered body, it is formed on the outer surface thereof. The cathode layer is not essential, and the solid electrolyte layer 3 and the cathode lead terminal 7 may be directly joined depending on the structure and material.

The cathode lead-out terminal 7 is usually joined to the cathode layer 4 by a conductive adhesive layer 6 such as a silver adhesive.
However, when the cathode extraction terminal 7 is directly joined to the solid electrolytic layer 3, the conductive adhesive layer 6 may not be required.

The anode lead-out terminal 8 is joined to the anode lead 5 inserted in the anode by welding or the like.

The exterior body 9 is formed so as to cover the entire device except for the penetrating portions of the cathode lead terminal 7 and the anode lead terminal 8. A ceramic, resin, or metal case may be used as the exterior body, but an exterior resin is used in the illustrated embodiment. The exterior resin is
Those formed by molding or dip molding are preferred. As the resin, for example, an epoxy resin can be used.

FIG. 1 is a process chart showing an example of a method for manufacturing a solid electrolytic capacitor of the present invention.

First, an anode is formed by etching a valve metal foil or forming a sintered body of a valve metal powder.
Next, a dielectric oxide film is formed on the surface of the anode, and a solid electrolyte layer is formed on the oxide film. Then, a cathode layer is formed as needed. The steps so far may be performed by a conventionally performed method.

In the step shown in FIG. 1, after forming the cathode layer, the capacitor element is impregnated with an organic compound by the method exemplified above. However, the impregnation of the organic compound may be performed at any stage after formation of the solid electrolyte layer and before formation of the exterior or sealing of the exterior. Also, by adding an organic compound to the forming solution of the solid electrolyte layer,
Organic compounds may be impregnated. As described above, a substance having a reduction potential equal to or higher than the hydrogen generation potential may be simultaneously added to this forming solution.

The substance having a reduction potential equal to or higher than the hydrogen generation potential can be contained in the solid electrolyte layer by bringing the solution containing the substance into contact with the solid electrolyte layer or a solid electrolyte which is a part of the solid electrolyte layer. Good. As described above,
This substance suppresses separation of the solid electrolyte layer during re-formation or aging.

Subsequently, in the assembling process, bonding with the cathode lead and the anode lead is performed. Finally, insertion and sealing into the exterior case or formation of the exterior resin are performed, and the capacitor element is arranged in the exterior body. If necessary, both terminal portions not covered with the exterior are bent in a predetermined direction.

The solid electrolytic capacitor thus obtained is
The capacitor element contains an organic compound. The ions are eluted from the solid electrolyte into the organic solvent in which the organic compound, particularly the organic compound present inside the solid electrolyte and at the interface between the dielectric oxide film and the solid electrolyte layer, is liquefied. Is given. Due to this self-healing ability, a solid electrolytic capacitor having a small leakage current can be efficiently provided.

The organic compound is preferably present in at least one selected from the inside of the solid electrolyte and the interface between the dielectric oxide film and the solid electrolyte layer. The same applies to a substance having a reduction potential equal to or higher than the hydrogen generation potential.

The organic compound does not need to be liquefied as a whole, but only needs to be locally liquefied by Joule heat generated by the leakage current in a portion where the leakage current flows to act as a solvent.

In the case where a conductive polymer is used as the solid electrolyte, when the solid electrolyte layer is impregnated with an organic compound, the conductive polymer is formed in a portion where a defect of the dielectric oxide film occurs when a voltage is applied. The dopant inside is easily removed (easy to be undoped). When undoped, the resistance value of the conductive polymer increases. Such a secondary effect can also reduce the leakage current.

[0070]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

Example A: Impregnation of Organic Compound Having Predetermined Melting Point and Boiling Point First, examples and comparative examples in which a difference in aging effect due to impregnation of an organic compound was confirmed will be described.

Comparative Example A First, for comparison, a solid electrolytic capacitor was prepared without impregnation with an organic compound. The tantalum powder is molded together with the lead, fired, and 1.4
A valve metal porous body of mm × 3.0 mm × 3.8 mm was formed. Next, a chemical conversion voltage of 20 V
Was subjected to an anodic oxidation treatment to form a dielectric oxide film layer. Thereafter, a solid electrolyte layer made of polypyrrole was formed on the surface of the dielectric oxide film layer including the inside of the pores by chemical oxidation polymerization of a pyrrole monomer.

Subsequently, a carbon layer and a silver layer were laminated on the solid electrolyte layer on the outer surface of the porous body to form a cathode layer. Thereafter, the cathode lead-out terminal was adhered to the cathode layer using a silver adhesive (conductive adhesive). On the other hand, an anode lead-out terminal was welded to the lead portion of the valve metal porous body serving as the anode. Further, an exterior body was formed by transfer molding of an epoxy resin. The exposed portions of the cathode lead terminal and the anode lead terminal were bent to obtain a solid electrolytic capacitor having a cross section similar to that of FIG.

Example A1 A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A, except that the capacitor element formed up to the cathode layer was impregnated with alcohol. Glycerin having a melting point of 17 ° C and a boiling point of 290 ° C was used as the alcohol. As the impregnation method, a method was used in which the capacitor element was immersed in a solution in which glycerin was dissolved in isopropyl alcohol at 20% by weight, and then the lifted element was heated to 120 ° C. to evaporate the isopropyl alcohol.

Example A2 A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A, except that the capacitor element formed up to the cathode layer was impregnated with alcohol. Glycerin having a melting point of 17 ° C and a boiling point of 290 ° C was used as the alcohol. As the impregnation method, a method in which two small containers each containing a capacitor element and glycerin are placed in a sealed container, glycerin is heated to 100 ° C. to generate steam, and the capacitor element is exposed to the steam. Adopted.

Example A3 A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A, except that the capacitor element formed up to the cathode layer was impregnated with alcohol. As the alcohol, stearyl alcohol having a melting point of 59 ° C. and a boiling point of 210 ° C. was used. As an impregnation method, the capacitor element was immersed in a solution in which stearyl alcohol was dissolved in ethanol at 3% by weight, and then the raised element was heated at 100 °
To evaporate the ethanol.

Example A4 A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A, except that the capacitor element formed up to the conductive polymer layer was impregnated with alcohol.
As the alcohol, stearyl alcohol having a melting point of 59 ° C. and a boiling point of 210 ° C. was used. As the impregnation method, a method was used in which the capacitor element was immersed in a solution in which stearyl alcohol was dissolved at 3% by weight in ethanol, and then the pulled-up element was heated to 100 ° C. to evaporate the ethanol.

Example A5 A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A, except that the phenol (derivative) was impregnated in the capacitor element formed up to the cathode layer. As phenol, 2,3-xylenol having a melting point of 73 ° C and a boiling point of 218 ° C was used. As the impregnation method, a method was used in which the capacitor element was immersed in a solution in which xylenol was dissolved in ethanol at 10% by weight, and then the lifted element was heated to 100 ° C. to evaporate the ethanol.

Example A6 A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A, except that phenol (derivative) was impregnated in the step of forming the conductive polymer layer. As phenol, melting point 73 ° C, boiling point 218 ° C
2,3-xylenol was used. As the impregnation method,
A method of performing a chemical oxidation polymerization method using a solution in which xylenol was dissolved was employed. Specifically, a solution in which xylenol is dissolved at 10% by weight in a pyrrole monomer solution (a water / ethanol mixed solution in which pyrrole is mixed and dissolved) is mixed with an oxidizing agent solution (a water / ethanol mixed solution in which iron (III) sulfate is dissolved). ), A solution in which xylenol was dissolved at 10 wt% was prepared, and a conductive polymer was formed by a chemical oxidation polymerization method by alternately immersing the two solutions. However, in the washing step after the formation of the conductive polymer layer, water having a low solubility of xylenol was used as the washing liquid. Thereby, xylenol was contained in the capacitor element simultaneously with the formation of the conductive polymer layer.

Example A7 A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A, except that the capacitor element formed up to the cathode layer was impregnated with an ester. As the ester, butyl benzoate having a melting point of −22 ° C. and a boiling point of 250 ° C. was used. As the impregnation method, butyl benzoate is
A method was used in which the capacitor element was immersed in a solution whose viscosity was reduced by heating to ℃.

Example A8 Except that the capacitor element formed up to the solid electrolyte layer was impregnated with ether,
A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A. As the ether, diphenyl ether having a melting point of 28 ° C. and a boiling point of 259 ° C. was used. As the impregnation method, a method was used in which the capacitor element was immersed in a solution in which diphenyl ether was dissolved at 5% by weight in ethanol, and then the pulled-up element was heated to 100 ° C. to evaporate the ethanol.

Example A9 A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A, except that the capacitor element formed up to the solid electrolyte layer was impregnated with ketone. As the ketone, holon having a melting point of 28 ° C. and a boiling point of 199 ° C. was used. As the impregnation method, 5% by weight of holon in ethanol
A method was used in which the capacitor element was immersed in the dissolved solution, and then the pulled-up element was heated to 100 ° C. to evaporate ethanol.

Example A10 A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A, except that the capacitor element formed up to the cathode layer was impregnated with a fatty acid. Fatty acids include stearic acid having a melting point of 71 ° C and a boiling point of 360 ° C (pK
a> 4.6) was used. As the impregnation method, a method of immersing the capacitor element in a melt obtained by heating stearic acid to 100 ° C. was adopted.

Example A11 A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A, except that the capacitor element formed up to the cathode layer was impregnated with an amine. As the amine, triethanolamine having a melting point of 21 ° C. and a boiling point of 360 ° C. was used. As the impregnation method, a method was used in which the capacitor element was immersed in a solution in which triethanolamine was dissolved at 5% by weight in ethanol, and then the pulled-up element was heated to 100 ° C. to evaporate the ethanol.

Example A12 A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A except that the capacitor element formed up to the cathode layer was impregnated with an amine. As the amine, diphenylamine having a melting point of 53 ° C. and a boiling point of 310 ° C. was used. As an impregnation method, diphenylamine is
A method was used in which the capacitor element was immersed in a melt obtained by heating to ° C.

Example A13 A solid electrolytic capacitor was obtained in the same manner as in Example A1, except that the nitro group-containing compound was contained in the capacitor element formed up to the solid electrolyte layer. Nitro group-containing compound has a melting point of 165 ° C
Of 4-nitrophthalic acid was used. This capacitor element contains glycerin and nitrophthalic acid. Nitrophthalic acid is impregnated with 2% by weight of 4%.
Immersing the capacitor element in a water / ethanol mixed solution containing nitrophthalic acid,
A method was employed in which water / ethanol was evaporated by heating to ° C.

Example A14 A solid electrolytic capacitor was obtained in the same manner as in Example A1, except that a nitro group-containing compound was contained in the step of forming the conductive polymer layer. As the nitro group-containing compound, a melting point of 54 ° C. and a boiling point of 2
3-Nitroanisole at 60 ° C was used. This capacitor element contains glycerin and nitroanisole. As a method of impregnating nitroanisole, a method of performing a chemical oxidation polymerization method using a solution in which nitroanisole was dissolved was employed. Specifically, when a conductive polymer layer made of polypyrrole is formed by chemical oxidative polymerization of a pyrrole monomer, 1% by weight of 3-nitroanisole is used as a monomer solution and an oxidizing agent (iron (III) sulfate) solution. A solution of water / ethanol in which was dissolved was prepared, and alternately immersed in the two solutions to form a conductive polymer layer containing nitroanisole. However, in the washing step after the formation of the conductive polymer layer, water having low solubility of nitroanisole was used as the washing liquid.

Example A15 A solid electrolytic capacitor was obtained in the same manner as in Comparative Example A, except that the capacitor element formed up to the solid electrolyte layer was impregnated with a nitro group-containing compound. As the nitro group-containing compound, 3-nitroanisole having a melting point of 54 ° C and a boiling point of 260 ° C was used. As the impregnation method, a method was used in which the capacitor element was immersed in a solution in which 3-nitroanisole was dissolved at 3% by weight in ethanol, and then the lifted element was heated to 100 ° C. to evaporate the ethanol.

From Comparative Example A and Examples A1 to A15, solid electrolytic capacitors having a rated value of 6.3 V and a standard value of 150 μF were obtained.

These solid electrolytic capacitors were subjected to an aging treatment for one hour by applying a voltage of 10 V at room temperature. For each example and comparative example, 10
No capacitors were processed.

As a result, in the capacitor of Comparative Example A, the leakage current was still as large as 20 to 100 μA, and could not be reduced to a practical range. On the other hand, in each of the capacitors of the above embodiments, the leakage current was reduced to 5 μA or less in all of the treatments for several minutes, and the leakage current could be suppressed to a practically acceptable level.

In order to make the leakage current of the capacitor of Comparative Example A within the practical range, it is necessary to absorb moisture at a temperature of 85 ° C. and a relative humidity of 85%, and then immediately carry out aging treatment by applying a 10 V voltage at the above temperature. did. As a result, all the leakage currents could be reduced to 5 μA or less, but the time required for the aging treatment reached ten and several hours including the moisture absorption time. Further, since this capacitor contains a large amount of water, the water was rapidly vaporized due to heating during solder mounting, and cracks occurred on the exterior. To prevent this, a drying step was required after the aging treatment. For this reason, the aging process as a whole is further lengthened. After drying at 120 ° C. for 40 hours, the leakage current was about 10 μA on average. An increase in the leakage current was observed as compared with that before the drying treatment. This is considered to be because the thermal stress was applied during the drying and the oxide film was damaged again.

Further, 100 capacitors after aging treatment (for Comparative Example A, capacitors that were subjected to aging treatment after moisture absorption and re-dried) were prepared, and soldered to a substrate. Thereafter, as an acceleration reliability test, a voltage 1.2 times the rated voltage was applied for 500 hours in an environment of 120 ° C. When the leakage current of each capacitor was evaluated after the test, seven capacitors of Comparative Example A had a leakage current of 30 μA or more. On the other hand, none of the capacitors of the above-described embodiments increased the leakage current to 10 μA or more.

The capacitance of each capacitor after aging was measured to be 135 μm.
F to 165 µF, all of which are standard values (150 µF)
There was no significant difference. In the capacitors of Examples A1 to A12, the capacitance was distributed in the range of 135 μF to 155 μF, which was slightly lower. On the other hand, in the capacitors of Examples A13 and A14 in which the nitro group-containing compound was simultaneously added and the capacitor of Example A15 in which the nitro group-containing compound was contained as an organic compound, the capacitors of 150 μF to 165 were used.
A high capacitance of μF was maintained.

As described above, it was confirmed that the capacitors of the above-described embodiments can efficiently reduce the leakage current. Further, when a compound having a reduction potential equal to or higher than the hydrogen generation potential, such as a nitro group-containing compound, is contained, it is possible to obtain a capacitor in which a decrease in capacitance due to aging treatment for reducing leakage current is suppressed.

Although the present embodiment has been described with reference to a molded article, the same effect can be obtained with a dip molded article. For molded products and dip molded products,
In particular, the leakage current tends to increase due to the stress at the time of resin curing when forming the exterior. Therefore, the application of the present invention is preferable.

However, the leakage current reducing effect also works effectively for a case-inserted product using a case as an exterior body. In particular, when the capacitor element is completely sealed in a case made of ceramic, resin, metal, or the like, it becomes difficult to absorb moisture to provide a repairing action. The application of the present invention is preferable for such a capacitor.

In this embodiment, a tantalum solid electrolytic capacitor is shown, but the same effect can be obtained with a capacitor using niobium or aluminum for the anode. In particular, when an amine was contained in the aluminum electrolytic capacitor, a capacitor having a smaller leakage current was obtained than in the case where other organic compounds were contained. For example, when an aluminum electrolytic capacitor manufactured under the same conditions is compared with a case where glycerin is impregnated and a case where triethanolamine is impregnated, the leakage current in the former was 10 μA on average, while the leakage current in the latter was 10 μA. Were all 5 μA or less.

Example B: Impregnation of a substance having a reduction potential equal to or higher than the hydrogen generation potential Next, the effect of the addition of a substance having a reduction potential equal to or higher than the hydrogen generation potential on the capacitance during re-chemical formation was confirmed. Examples and comparative examples will be described.

(Comparative Example B) First, for comparison, a solid electrolytic capacitor was prepared without impregnation with the above substances. Tantalum powder is molded with leads and fired to 1.4m
A valve metal porous body of mx 3.0 mm x 3.8 mm was formed. Next, the entire surface of the porous body except the tip of the lead was subjected to anodizing treatment at a formation voltage of 20 V in a phosphoric acid aqueous solution to form a dielectric oxide film layer. Further, a solid electrolyte layer made of polypyrrole was formed on the surface of the dielectric oxide film layer including the inside of the pores by chemical oxidation polymerization of a pyrrole monomer. The solid electrolyte layer was formed by alternately immersing the oxidizing agent solution and the pyrrole solution.

After the formation of the solid electrolyte layer, the device was cooled to 30 ° C.
In acetic acid / ethanol mixed solution, and a DC voltage of 15 V was applied for 10 minutes to re-form the oxide film. This chemical oxidative polymerization and re-chemical conversion treatment were repeated eight times each.

Subsequently, a carbon layer and a silver layer were laminated on the solid electrolyte layer on the outer surface of the porous body to form a cathode layer. Thereafter, the cathode lead-out terminal was adhered to the cathode layer using a silver adhesive (conductive adhesive). On the other hand, an anode lead-out terminal was welded to the lead portion of the valve metal porous body serving as the anode. Further, an exterior body was formed by transfer molding of an epoxy resin. The exposed portions of the cathode lead terminal and the anode lead terminal were bent to obtain a solid electrolytic capacitor having a cross section similar to that of FIG.

This solid electrolytic capacitor was heated at a temperature of 80 ° C.
After absorbing moisture under the condition of a relative humidity of 70%, the rated voltage (6.
3V) was applied for 30 minutes to perform aging. Thereafter, drying was performed at 120 ° C. The leakage current and the capacitance (120
Hz) were 8.8 μA and 141 μF, respectively, on average.

(Examples B1 to B7) Comparative Examples B to B7 except that a predetermined concentration of 4-nitrophthalic acid (melting point: 165 ° C.) was added to the pyrrole solution used for forming the solid electrolyte layer.
In the same manner as in the above, a solid electrolytic capacitor was obtained.

Each of the thus obtained solid electrolytic capacitors 2
Table 1 shows the average values of zero leakage current, capacitance (120 Hz) and capacitance ratio (100 kHz / 120 Hz) together with the results of Comparative Example B.

(Table 1) ―――――――――――――――――――――――――――――――― Sample Nitrophthalic acid concentration Capacitance (120 Hz ) Capacitance ratio Leakage current (μF) (100kHz / 120Hz) (μA) ―――――――――――――――――――――――――――――― -Comparative Example B-141 0.45 8.8 Example B1 10 ppm 152 0.63 3.0 Example B2 50 ppm 161 0.64 1.0 Example B3 1% 162 0.62 2.0 Example B4 5% 162 0.64 1.0 Example B5 10% 163 0.61 1.5 Example B6 15% 162 0.53 2.0 Example B7 20% 150 0.50 3.0 ――――― ―――――――――――――――――――――――――――――

In each of the above examples, nitrophthalic acid was added to the pyrrole solution so that the pyrrole concentration in the solid electrolyte layer became the above value. For example, Example B
The pyrrole solution used to make the capacitor of No. 2 was 50 p
pm 4-nitrophthalic acid was added.

As shown in Table 1, when the concentration of nitrophthalic acid is 50 ppm (by weight) to 15%, 160
A capacitance of more than μF was obtained. It is considered that the reason why the capacitance was reduced by the concentration higher than 10% was that a large amount of nitrophthalic acid was present as an impurity in the solid electrolyte and the area of the oxide film directly covered by the solid electrolyte was reduced. Further, the decrease in the capacitance ratio (100 kHz / 120 Hz) in Table 1 is an index indicating the level of decrease in high-frequency response due to separation inside the solid electrolyte, and from this viewpoint, the concentration of nitrophthalic acid is 10 ppm to 10 ppm. %, Good results were obtained. Further, in each of the examples, the leakage current is lower than that of the comparative example because nitrophthalic acid exists to the deep part of the pores and nitrophthalic acid gives an appropriate conductivity to the electrolytic solution at the time of re-formation. This is because the defect was repaired more quickly.

Further, a solid electrolytic capacitor was manufactured as follows. (Comparative Example C) A solid electrolytic capacitor was obtained in the same manner as in Comparative Example B except that aging was omitted.

(Example C1) A solid electrolytic capacitor was obtained in the same manner as in Example B2 except that aging was omitted.

(Example C2) A solid electrolytic capacitor was obtained in the same manner as in Example B2, except that aging was omitted, and the electrolytic solution used for re-chemical formation was changed from an aqueous solution of ethanol in acetic acid to water.

(Example C3) A solid electrolytic capacitor was obtained in the same manner as in Example B2, except that aging was omitted and the electrolytic solution used for re-formation was changed from an aqueous acetic acid solution to ethanol.

(Example C4) A solid electrolytic capacitor was obtained in the same manner as in Example B2 except that 3-nitroanisole was used instead of 4-nitrophthalic acid.

Table 2 shows the leakage current and the capacitance (120 Hz) of the 20 solid electrolytic capacitors obtained from Comparative Example C and Examples C1 to C4 together with the results of Comparative Example B and Example B2. .

(Table 2) ――――――――――――――――――――――――――――――――― Sample Regeneration Aspiration Capacitance Leakage current Reducing substance Electrolyte (μF) (μA) ――――――――――――――――――――――――――――――― Comparative Example B − Acetic acid / EtOH ○ 141 8.8 Example B2 NP Acetic Acid / EtOH ○ 161 1.0 Example C4 NA Acetic Acid / EtOH ○ 159 1.5 ――――――――――――――――――――― Comparative Example C-Acetic acid / EtOH x 144 75 Example C1 NP Acetic acid / EtOH x 159 11 Example C2 NP water x 156 13 Example C3 NP EtOH x 158 8.9 ―――――――――――――――――――――――――――――――――

NP is 4-nitrophthalic acid, NA is 3-
Nitroanisole, EtOH is ethanol, ○ is aging applied, and × is aging not applied.

[0117]

As described above, according to the present invention,
The presence of the organic compound can provide a solid electrolytic capacitor capable of aging the solid electrolytic capacitor more efficiently than aging relying on moisture absorption and reducing the leakage current, and a method of manufacturing the same. Further, according to the present invention, it is possible to provide a solid electrolytic capacitor capable of reducing a leakage current while suppressing a decrease in capacitance by using a substance having a reduction potential equal to or higher than a hydrogen generation potential, and a method for manufacturing the same.

[Brief description of the drawings]

FIG. 1 is a process chart showing an example of a method for manufacturing a solid electrolytic capacitor of the present invention.

FIG. 2 is a sectional view showing an example of the solid electrolytic capacitor of the present invention.

FIG. 3 is a sectional view showing another example of the solid electrolytic capacitor of the present invention.

FIG. 4 is a sectional view showing another example of the solid electrolytic capacitor of the present invention.

FIG. 5 is a cross-sectional view for explaining a solid electrolyte membrane peeling phenomenon that may occur with the repair of an oxide film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode 2 Dielectric oxide film layer 3 Solid electrolyte layer 4 Cathode layer 5 Anode lead 6 Conductive adhesive layer 7 Cathode lead terminal 8 Anode lead terminal 9 Outer body 10 External terminal 11 Cathode foil

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01G 9/00 H01G 9/24 AB (72) Inventor Shoko 1006 Kadoma, Kazuma, Kazuma, Osaka Matsushita Electric Within Sangyo Co., Ltd. (72) Inventor Toshitaka Kato 1006 Kadoma, Kazuma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. (72) Inventor Masakazu Tanahashi 1006 Odaka Kadoma, Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd.

Claims (30)

[Claims] 1. A solid electrolytic capacitor having a capacitor element including a valve metal, an oxide film layer formed on a surface of the valve metal, and a solid electrolyte layer formed on the oxide film layer in an exterior body. Wherein the capacitor element contains an organic compound having a boiling point of 150 ° C. or higher and a melting point of 150 ° C. or lower. 2. The solid electrolytic capacitor according to claim 1, wherein the melting point of the organic compound is higher than 25 ° C. 3. The solid electrolytic capacitor according to claim 1, wherein the organic compound is at least one selected from alcohol, phenol, ester, ether and ketone. 4. The solid electrolytic capacitor according to claim 1, wherein the organic compound is a fatty acid. 5. The solid electrolytic capacitor according to claim 1, wherein the organic compound is an amine. 6. The solid electrolytic capacitor according to claim 1, wherein the boiling point of the organic compound is 200 ° C. or higher. 7. The solid electrolytic capacitor according to claim 1, wherein the organic compound is present in at least one selected from the inside of the solid electrolyte and the interface between the dielectric oxide film and the solid electrolyte layer. 8. The solid electrolytic capacitor according to claim 1, wherein the capacitor element further contains a substance having a reduction potential equal to or higher than the hydrogen generation potential. 9. A solid electrolytic capacitor having a capacitor element including a valve metal, an oxide film layer formed on a surface of the valve metal, and a solid electrolyte layer formed on the oxide film layer inside an outer package. Wherein the capacitor element contains a substance having a reduction potential equal to or higher than a hydrogen generation potential. 10. The solid according to claim 8, wherein the substance having a reduction potential equal to or higher than the hydrogen generation potential is present in at least one selected from the inside of the solid electrolyte and the interface between the dielectric oxide film and the solid electrolyte layer. Electrolytic capacitor. 11. A substance having a reduction potential equal to or higher than the hydrogen generation potential is selected from perchloric acid and its salts, permanganic acid and its salts, chromic acid and its salts, peroxodisulfuric acid and its salts, and nitro group-containing compounds. The solid electrolytic capacitor according to claim 8, which is at least one selected from the group consisting of: 12. The solid electrolytic capacitor according to claim 8, wherein the substance having a reduction potential equal to or higher than the hydrogen generation potential is a substance that does not release gas by reduction. 13. The solid electrolytic capacitor according to claim 8, wherein the substance having a reduction potential equal to or higher than the hydrogen generation potential is a nitro group-containing compound. 14. The solid electrolytic capacitor according to claim 1, wherein the solid electrolyte is a conductive polymer. 15. The solid electrolytic capacitor according to claim 1, wherein the exterior body is a resin formed by molding or dip molding. 16. A solid electrolytic capacitor having a capacitor element including a valve metal, an oxide film layer formed on the surface of the valve metal, and a solid electrolyte layer formed on the oxide film layer inside an outer package. The method for producing
A solid electrolytic capacitor comprising: adding an organic compound having a boiling point of 50 ° C. or more and a melting point of 150 ° C. or less to the capacitor element; and disposing the capacitor element in a state containing the organic compound inside the exterior body. Manufacturing method. 17. The capacitor element according to claim 16, wherein the capacitor element is impregnated with a solution obtained by dissolving an organic compound in a solvent, and the solvent is evaporated by heating. Method for manufacturing solid electrolytic capacitor. 18. The method for manufacturing a solid electrolytic capacitor according to claim 16, wherein the organic compound is contained in the capacitor element by impregnating the capacitor element with vapor generated by heating the organic compound. 19. The method for producing a solid electrolytic capacitor according to claim 16, wherein said organic compound is contained in said capacitor element by impregnating said capacitor element with an organic compound liquefied by heating. 20. The method for producing a solid electrolytic capacitor according to claim 16, wherein said organic compound is contained in said capacitor element by impregnating said capacitor element with an organic compound whose viscosity has been reduced by heating. 21. The method for producing a solid electrolytic capacitor according to claim 16, wherein the organic compound is contained in a capacitor element by adding an organic compound to a solution for forming a solid electrolyte layer. 22. The method for manufacturing a solid electrolytic capacitor according to claim 16, further comprising a step of applying a DC voltage to repair a defect of the oxide film layer that contacts the liquid of the organic compound. 23. The method for manufacturing a solid electrolytic capacitor according to claim 22, wherein the organic compound is liquefied by heat generated upon application of the DC voltage, and defects of the oxide film layer are repaired by applying the DC voltage. 24. The capacitor element further containing a substance having a reduction potential equal to or higher than the hydrogen generation potential.
3. The method for manufacturing a solid electrolytic capacitor according to 1. 25. A solid electrolytic capacitor having a capacitor element including a valve metal, an oxide film layer formed on the surface of the valve metal, and a solid electrolyte layer formed on the oxide film layer inside an outer package. Prior to placing the capacitor element inside the exterior body,
A method for producing a solid electrolytic capacitor, characterized in that a substance having a reduction potential equal to or higher than a hydrogen generation potential is contained in the solid electrolyte layer. 26. The solid according to claim 24, wherein a substance having a reduction potential equal to or higher than a hydrogen generation potential is added to a solution for forming the solid electrolyte layer so that the solid electrolyte layer contains the substance. Manufacturing method of electrolytic capacitor. 27. A solution containing a substance having a reduction potential equal to or higher than a hydrogen generation potential is brought into contact with a solid electrolyte layer or a solid electrolyte which is to be a part of the solid electrolyte layer, whereby the substance is contained in the solid electrolyte layer. A method for manufacturing the solid electrolytic capacitor according to claim 24. 28. The method for producing a solid electrolytic capacitor according to claim 24, wherein a substance having a reduction potential equal to or higher than the hydrogen generation potential is contained in the solid electrolyte layer in a range of 50 ppm to 10% by weight. 29. Before arranging a capacitor element inside an exterior body, a solvent is brought into contact with a solid electrolyte layer containing a substance having a reduction potential equal to or higher than a hydrogen generation potential or a solid electrolyte which becomes a part of the solid electrolyte layer. 26. The method for manufacturing a solid electrolytic capacitor according to claim 24, further comprising a step of applying a DC voltage in a state where the oxide film layer is defective to repair a defect of the oxide film layer. 30. The method for manufacturing a solid electrolytic capacitor according to claim 29, wherein the step of forming a part of the solid electrolyte layer and the step of repairing a defect in the oxide film layer are alternately repeated to form the solid electrolyte layer. .