JP2002083738A - Lead wire for capacitor, solid electrolytic capacitor, and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable lead wire for capacitor, which has less leakage current and few leakage current fluctuations against thermal stress, at the time of soldering, and to provide a solid electrolytic capacitor using the wire and the manufacturing method thereof. SOLUTION: A processing for dropping wettability against conductive polymer is performed on at least a part of an anode tab 6 in the solid electrolytic capacitor. Thus, the highly reliable solid electrolytic capacitor having less leakage current fluctuation against thermal stress at the time of soldering can stably be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor lead wire suitable for a wound solid electrolytic capacitor using a conductive polymer as a solid electrolyte, a solid electrolytic capacitor using the same, and a method of manufacturing the same.

[0002]

2. Description of the Related Art With the increase in the frequency of electronic equipment, a large-capacity electrolytic capacitor having better impedance characteristics in a high-frequency region than ever has been required for an electrolytic capacitor as an electronic component. In recent years, in order to reduce the impedance in the high frequency region, an electrolytic capacitor using a solid electrolyte such as a conductive polymer having a high electric conductivity or a tetracyano xydimethane complex (hereinafter, referred to as TCNQ) has been studied. In addition, in order to meet the demand for large capacity, a wound type (anode foil and cathode foil with a separator interposed therebetween), which is structurally easier to increase the capacity compared to the case where electrode foils are laminated, is used. Application of a conductive polymer solid electrolyte or TCNQ to an aluminum electrolytic capacitor having a rotated structure) has been made.

[0003] As the conductive polymer used for the electrolyte, polyethylene dioxythiophene, polypyrrole and polyaniline formed by chemically oxidizing and polymerizing ethylenedioxythiophene with an appropriate oxidizing agent are generally well known.

The structure of such a wound type aluminum electrolytic capacitor is a non-solid type using a liquid electrolyte as an electrolyte, as is generally well known in the past. In this non-solid aluminum electrolytic capacitor, A device for preventing leakage of electrolyte from a slight gap between a through hole provided in a sealing material made of synthetic rubber or the like for leading the electrode tab to the outside and an electrode tab inserted into the through hole. Have been proposed.

In order to prevent the leakage of the electrolytic solution, the electrode tab is devised by controlling the potential difference between the electrode tab and the cathode foil by electrochemically providing an oxide film layer on the electrode tab portion made of aluminum, Suppression of an electrochemical reaction caused by a potential difference current has been proposed. In addition, by providing an insulating resin layer (epoxy resin, polyamide, polyimide, polyethylene, polypropylene, etc.) on the surface of the conductive electrode tab, the surface of the electrode tab is rendered nonconductive, and the electrochemical reaction generated at the tab portion is suppressed. It has been proposed to.

Further, a capacitor sintered element obtained by molding and sintering a metal powder, such as a tantalum electrolytic capacitor, is immersed in a liquid epoxy resin, and the epoxy resin adhered to the capacitor sintered element is cured to form a package. For the solid electrolytic capacitor used as the material, a fluorine-based resin that lowers the wettability to the epoxy resin must be used in advance so that the liquid epoxy resin does not adhere to the lead wire portion derived from the capacitor sintered body element and hinder soldering. There has been proposed a process of applying to a lead wire (not to an electrode terminal inside a capacitor, but to a portion corresponding to an external terminal to be soldered when the capacitor is mounted on a circuit board).

[0007]

However, in the conventional solid electrolytic capacitor using a conductive polymer as a solid electrolyte (particularly, a wound solid aluminum electrolytic capacitor), the leakage current value is large, and the solid electrolytic capacitor has a large leakage current. Has a problem that the leakage current is liable to increase remarkably when subjected to thermal stress.

The present invention solves such a conventional problem,
Capacitor lead wire and solid electrolytic using the same, which can realize a low impedance and highly reliable solid electrolytic capacitor with low leakage current and little fluctuation of leakage current even when subjected to thermal stress during soldering It is an object of the present invention to provide a capacitor and a method for manufacturing the same.

[0009]

According to a first aspect of the present invention, there is provided an electrode tab made of an aluminum wire having a flat portion, and an electrode tab electrically connected to the electrode tab. And at least a part of the electrode tab, polypyrrole, polyethylene dioxythiophene polystyrene sulfonic acid, polyethylene dioxythiophene, pyrrole, ethylene dioxythiophene, aliphatic sulfonic acid, toluene sulfonic acid, naphthalene sulfonic acid, anthraquinone Sulfonic acid, styrene sulfonic acid, polystyrene sulfonic acid and a derivative of the above compound, and a treatment for reducing wettability with respect to a mixture of at least one or more of methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, and water. With this configuration, a conductive polymer such as polyethylene dioxythiophene is provided on the electrode tab part electrically connected to the anode foil, which is a place where leakage current is particularly likely to be large. Monomers such as ethylenedioxythiophene,
A dopant such as toluenesulfonic acid, a polymerization solvent such as n-butanol, an oxidizing agent such as a trivalent iron salt, and the like hardly adhere during polymerization (wetting property lowering effect). For this reason, the adhesion of the conductive polymer acting as a cathode body to the electrode tab portion can be suppressed. As a result, when a solid electrolytic capacitor is formed using this capacitor lead wire, the leakage current draw-out portion is not formed. Due to the cutoff effect, an operation and effect that a solid electrolytic capacitor having a small leakage current can be obtained is obtained.

According to a second aspect of the present invention, in the first aspect, the treatment for reducing the wettability applied to at least a part of the electrode tab is a resin coating treatment. However, since the processing is stabilized by this configuration, the operation and effect obtained by the first aspect of the invention can be further stabilized.

In the case of a non-solid wound type aluminum electrolytic capacitor using an electrolytic solution as an electrolyte, in the above-mentioned method of coating a resin on a lead wire, the purpose of the treatment is to prevent the leakage of the electrolytic solution or the electric power. Since it suppresses chemical reactions (insulation of metal), select a resin material that is stable against the organic solvent and electrolyte that make up the electrolyte, and have a thickness that is sufficient to insulate the metal surface. It is best to coat. On the other hand, as far as we can confirm today, if an insulating layer sufficient to suppress the electrochemical reaction is to be provided on the surface of the metal tab, the thickness of the resin layer must be at least 10 μm or more. Was something.

However, in such a method, the conductive polymer, the monomer, or the like is applied to the electrode tab portion electrically connected to the anode foil, which is a portion where the leakage current is particularly likely to be large.
Since the adhesion of the dopant, the polymerization solvent, the oxidizing agent and the like during the polymerization cannot be suppressed, the conductive polymer acting as the cathode adheres to the electrode tab portion, and as a result, the effect of blocking the leakage current is not obtained, and the leakage current is not obtained. Was difficult to reduce.
If this method is used to reduce the leakage current, not only is it not possible to obtain the effect of cutting off the leakage current extraction part, but also to ensure insulation on the surface of the electrode tab for the purpose of insulation. It must be coated with a thick resin (polypropylene, polyethylene, polyimide, polyamide, epoxy, etc.), which causes unevenness on the surface of the electrode tab, and the hole for the electrode tab penetration of the sealing material and the electrode. External stress may be applied to the capacitor element filled with polymer when assembling the capacitor, as this will reduce the mating of the contact surface with the tab and the insertion of the electrode tab into the hole for penetrating the electrode tab when assembling the capacitor. , Which is not preferable because it has the disadvantage of increasing the leakage current.

According to a third aspect of the present invention, in the second aspect, the resin coated on at least a part of the electrode tab is 2- (perfluoroalkenyloxy) methyl acrylate or 2- (perfluoroalkenyloxy) methyl acrylate. Perfluoroalkenyloxy) ethyl acrylate, 2- (perfluoroalkyloxy) methyl acrylate, 2- (perfluoroalkyloxy) ethyl acrylate, perfluoroalkenyl polyvinyl phenyl ether, at least one or more selected from the group of perfluoroalkyl polyvinyl phenyl ether The composition is a resin made of a polymer that is composed, and by this configuration, chemicals (polymerizable monomer, oxidizing agent, dopant, Polymerization solvent ) Relative to, it is possible to form the process layer by significantly lower resin wettability, claim 2
The effect obtained by the invention described in (1) can be further enhanced, and as a result, the effect that leakage current can be further reduced can be obtained.

[0014] In addition, since the resin coating layer does not require insulation in the structure of the present invention, even if the thickness of the resin coating layer is small, a uniform layer having no defect is formed on the surface of the electrode tab. Since there is no adverse effect of increasing the unevenness of the surface of the electrode tab, the mating property of the contact surface between the electrode tab penetration hole of the sealing material and the electrode tab and the electrode tab penetration hole can be provided. The insertability of the electrode tabs is not impaired by the resin coating process. As a result, the external stress applied to the capacitor element during the assembly of the capacitor can be reduced, and the leakage current caused by the external stress increases. Can also be suppressed.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the resin coated on at least a part of the electrode tab has a surface tension of 30 m in a coated state.
N / m or less of a fluorine-containing resin, a silicon-containing resin, a titanium-containing resin, and a mixture of at least one or more of the above-mentioned resins. Claims (2) is to form a treatment layer with a resin having extremely low wettability with respect to chemicals (polymerizable monomer, oxidizing agent, dopant, polymerization solvent, etc.) used when filling the capacitor element with The effect obtained by the invention described in (1) can be further enhanced, and as a result, the effect that leakage current can be further reduced can be obtained.
In addition, resin whose surface tension exceeds 30 mN / m (for example,
In the case of polyethylene; surface tension of 31 mN / m), the effect of lowering the wettability is not sufficient, so that the adhesion of the conductive polymer acting as the cathode body to the electrode tab cannot be suppressed. Cannot be sufficiently reduced.

According to a fifth aspect of the present invention, in the second aspect, the resin coated on at least a part of the electrode tab is compatible with a fluorinated solvent and / or a chlorinated solvent. It must be of a composition that is soluble,
In the invention according to claim 6, the resin coated on at least a part of the electrode tab is polyfluoroether, hydrofluoroether, methyl perfluoroether isobutyl ether, methyl perfluorobutyl ether, fluorobenzene, trifluoromethylbenzene, Bistrifluoromethylbenzene, xylene hexafluoride, hexafluoropropene, and a fluorine-containing resin that dissolves in an amount of 0.1% by weight or more in a mixed fluorine-containing solvent of at least one or more of dielectrics and / or multimers thereof. This configuration makes it possible to easily solubilize a fluorine-containing resin having a small surface tension, particularly having a large effect of reducing wettability, in a solvent, and thus it is possible to adjust a high-concentration fluorine-containing resin solution. This high-concentration fluorine-containing tree Solution by using, it is easy to deposit a resin layer having no uniform and defect of constant thickness on the surface of the electrode tabs, because the process is stabilized,
The operation and effect that the operation and effect obtained by the invention of claim 2 can be further stabilized can be obtained.

Further, fluorine-containing solvents and chlorine-containing solvents are relatively safe, are flame-retardant, and have a high vapor pressure.
This is preferable because it can be performed in a low temperature range such as about 0 ° C. Also, among these, hydrofluoroether,
Methyl perfluoroether isobutyl ether, methyl perfluorobutyl ether, and bistrifluoromethylbenzene are preferable because they have a zero ozone depletion potential and have few environmental problems.

According to a seventh aspect of the present invention, there is provided a strip-shaped anode foil and a cathode foil to which the capacitor lead wires according to any one of the first to sixth aspects are electrically connected, respectively. A capacitor element constructed by winding a separator between them and a solid electrolytic capacitor made of a conductive polymer solid electrolyte filled in the capacitor element. Conductive polymers, monomers, dopants, polymerization solvents, oxidizing agents, and the like are less likely to adhere to the electrode tabs that are electrically connected to the anode foil, which is likely to become large, during polymerization (wetting property lowering effect). Adhesion of the conductive polymer acting as a cathode body to the electrode tab portion can be suppressed, and as a result, the leakage current is reduced by the blocking effect of the leakage current extraction portion. Effect that can Rukoto is obtained.

[0020] The invention according to claim 8 of the present invention is the invention according to claim 7, wherein the conductive polymer is polypyrrole, polyethylenedioxythiophene polystyrenesulfonic acid, polyethylenedioxythiophene and a derivative of the above compound. The configuration is any one or more, with this configuration, these conductive polymers are fluorine-containing resin, which is a coating resin for the electrode tab, significantly poor wettability to the silicon-containing resin, the above-mentioned, The effect of lowering the wettability can be sufficiently and stably exhibited, and the adhesion of the polymer to the electrode tab portion is less likely to occur. As a result, the leakage current is extremely small, and the leakage due to the thermal stress at the time of soldering occurs. The operation and effect of obtaining a solid electrolytic capacitor with very little current fluctuation can be obtained. In the case where the conductive polymer has a fluorine-containing group or a chlorine-containing group as a substituent or a polyaniline-based one, the compatibility between the conductive polymer and the coating resin layer of the electrode tab tends to be high. It is difficult to sufficiently exert the effect of the present invention because the effect of lowering the wettability is not sufficiently exhibited, and the coating resin layer is easily dissolved and easily peeled off during polymerization.

According to a ninth aspect of the present invention, in the seventh aspect, the repeating unit monomer constituting the conductive polymer is any one of pyrrole, ethylenedioxythiophene, and a derivative of the above compound. With this configuration, these repeating unit monomers have a significantly poor wettability with respect to the fluorine-containing resin and the silicon-containing resin that are the coating resins for the electrode tabs. The lowering effect can be sufficiently and stably exhibited, and the polymer is hardly adhered to the electrode tab portion. As a result, the leakage current is extremely small, and the leakage current fluctuates even with thermal stress during soldering. Thus, an operation and effect that a solid electrolytic capacitor with extremely small amount can be obtained can be obtained. In the case where the monomer has a fluorine-containing group or a chlorine-containing group as a substituent or an aniline-based monomer, the compatibility between the monomer and the coating resin layer of the electrode tab tends to be high. Is difficult to be displayed
Since the coating resin layer dissolves at the time of polymerization and easily peels off, it is difficult to exert the effect of the present invention sufficiently, which is not preferable.

According to a tenth aspect of the present invention, in the invention according to the seventh aspect, the dopant constituting the conductive polymer and the compound thereof are an aliphatic sulfonic acid, toluene sulfonic acid, naphthalene sulfonic acid, Anthraquinone sulfonic acid, styrene sulfonic acid, polystyrene sulfonic acid, or a derivative of the above compound, and these dopants allow these dopants to be used as a fluorine-containing resin, a silicon-containing resin, which is a coating resin for the electrode tab. Since the wettability is remarkably poor, the same effect as that obtained by the eighth aspect is obtained.

When the dopant has a fluorine-containing group or a chlorine-containing group as a substituent (eg, fluoromethanesulfonic acid), the compatibility between the dopant and the coating resin layer of the electrode tab tends to be high. It is difficult to sufficiently exert the effect of the present invention because the coating resin layer dissolves during polymerization and easily peels off, and the effect of the present invention is difficult to sufficiently exert.

According to an eleventh aspect of the present invention, in the invention according to the seventh aspect, the polymerization solvent used for filling the conductive polymer is methanol, ethanol, n-propyl alcohol, isopropyl alcohol, or the like. n-Butanol, water and a mixed solvent containing at least one or more of the above-mentioned solvents. With this configuration, these polymerization solvents can be used as a fluorine-containing resin or a silicon-containing resin as a coating resin for an electrode tab. Since the wettability is remarkably poor, the same effect as that obtained by the eighth aspect is obtained.

When the polymerization solvent is a fluorine-based solvent (such as fluorobenzene or bistrifluoromethylbenzene) or a chlorine-based solvent (such as chloroform or dichloromethane), the compatibility with the coating resin layer of the electrode tab tends to be high. Therefore, the effect of reducing the wettability is not sufficiently exhibited, and the coating resin layer is easily dissolved and easily peeled off during the polymerization, so that it is difficult to sufficiently exert the effect of the present invention, which is not preferable.

According to a twelfth aspect of the present invention, a strip-shaped anode foil and a cathode foil to which electrode tabs for leading lead terminals are respectively electrically connected are wound with a separator interposed therebetween. Step of forming a capacitor element, at least a part of the electrode tab, a conductive polymer,
The repeating unit monomer constituting the conductive polymer, the dopant constituting the conductive polymer and its compound, the solvent used for filling the conductive polymer, the oxidizing agent used for filling the conductive polymer and its compound A step of coating a resin that reduces wettability with respect to a mixture of at least one or more of the organic additive and the substance used when filling the conductive polymer, and a solid electrolyte made of the conductive polymer in the capacitor element. In the method for manufacturing a solid electrolytic capacitor having a filling step, the resin coating treatment step is a step of adhering a solution of a solvent-soluble resin to at least a part of an electrode tab, and vaporizing a solvent component of the solution of the solvent-soluble resin. -A method of manufacturing a solid electrolytic capacitor including a step of dissipating, which reduces wettability. Since the coating treatment of the resin which can be easily and uniformly with less leak current variation against thermal stress during leakage current is small and soldered,
The operational effect that a highly reliable solid electrolytic capacitor can be easily obtained is obtained.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial sectional perspective view showing the structure of a solid electrolytic capacitor according to the present invention.
FIG. 3B is a perspective view showing an aluminum electrode tab constituting the capacitor element and a cross-sectional view taken along a line AB, which is a main part thereof.

In FIG. 1, reference numeral 4 denotes a capacitor element. This capacitor element 4 has an anode lead 1 made of an aluminum foil having a surface roughened by an etching process and then formed with a dielectric oxide film by an oxidation process. 5 is connected to the anode tab 6 to which the cathode extraction lead 7 is joined to the cathode foil 2 made of aluminum foil, and the anode foil 1 and the cathode foil 2 thus configured are connected. The separator is interposed therebetween and wound with a separator 3 interposed therebetween. Further, a solid electrolyte (not shown) made of a conductive polymer or the like is formed between the anode foil 1 and the cathode foil 2. Is what it is.

The capacitor element 4 is housed in a bottomed cylindrical aluminum case 9, and the open end of the aluminum case 9 is led out of each of the anode foil 1 and the cathode foil 2 by a rubber sealing material 10. The outer lead-out anode lead 5 and the cathode lead 7 are sealed by penetrating the sealing material 10.

As shown in FIG. 2, the surface portion of the anode tab 6 (or the cathode tab 8) to which the anode lead 5 (or the cathode lead 7) is electrically joined reduces the wettability. Although it is covered with the treatment layer 11 (for example, a coating layer of a resin having a wettability reducing effect), the present invention is not limited to this configuration, and at least a part of the anode tab 6 is treated. If this is the case, a similar effect of reducing and stabilizing the leakage current can be obtained. Preferably, the treatment of the portion (the cylindrical portion of the electrode tab) where the inside of the electrode tab penetration hole of the sealing material 10 and the anode tab (or the cathode tab 8) are in contact is effective and economical. Further, the treatment may be performed on both the anode tab 6 and the cathode tab 8, or the treatment may be performed on one of the anode tabs 6. Also,
Due to the principle of the present invention, processing only on the cathode tab 8 is not effective.

Next, specific embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

(Embodiment 1) The aluminum portion of an aluminum electrode tab to which a lead terminal (iron core material has been subjected to copper flash plating and further subjected to tin plating) is welded to the aluminum portion, After immersing in a 3% by weight bistrifluoromethylbenzene solution of a fluororesin containing a copolymer of (perfluoroalkenyloxy) ethyl acrylate and 2- (perfluoroalkyloxy) ethyl acrylate, the solution is pulled up in an atmosphere at 85 ° C. After leaving for a minute, the solvent component of the solution attached to the electrode tab, bistrifluoromethylbenzene, was completely volatilized, thereby covering the entire aluminum portion of the electrode tab with the fluororesin. The thickness of the fluororesin coating layer was 0.5 to 1.0 μm as observed by an electron microscope. The surface tension of the coating layer was 17 mN / m.

The electrode tab of the lead wire thus prepared was used as an anode foil made of an aluminum foil having a dielectric oxide film formed thereon (withstand voltage 32 V of the dielectric oxide film) and a cathode foil made of an etched aluminum foil. And electrical bonding was obtained by caulking them.

Next, a non-woven fabric separator made of polyethylene terephthalate fiber (thickness: 50 μm, weighing 20 g /
m ² ) to form a wound (aluminum) electrolytic capacitor element (10% by weight of ammonium adipate in this capacitor element).
Frequency 120 when impregnated with ethylene glycol solution
The capacitance at 250 Hz was 250 μF).

Subsequently, the capacitor element was immersed in a 1.0% aqueous solution of polyethylene dioxythiophene polystyrene sulfonic acid, which is a conductive polymer, and pulled up.
Drying was performed at 150 ° C. for 5 minutes to form a layer of polyethylene dioxythiophene polystyrene sulfonic acid on the dielectric oxide films of the anode foil and the cathode foil and on the separator fibers.

Subsequently, this capacitor element was replaced with 1 part of ethylenedioxythiophene as a polymerizable monomer and ferric p-toluenesulfonate, which is an oxidizing agent and a dopant component.
Immersed in a solution containing 4 parts of n-butanol as a polymerization solvent and raised, and then left at 85 ° C. for 60 minutes to form polyethylene dioxythiophene, a chemically polymerizable conductive polymer, between the electrode foils. did.

Subsequently, after washing and drying the capacitor element, a sealing member made of resin vulcanized butyl rubber (consisting of 30 parts of butyl rubber polymer, 20 parts of carbon and 50 parts of inorganic filler, sealing body hardness: 70 IRHD [International] Rubber hardness unit]), sealed in an aluminum outer case, curled to seal the opening, and then passed both lead terminals derived from the anode foil and cathode foil through a polyphenylene sulfide seat plate. Then, the surface of the solid (aluminum) electrolytic capacitor was manufactured by bending the lead wire portion flat (size: 10 mm in diameter).
× height 10 mm, rated voltage 16 V).

An aging treatment was performed by applying a DC voltage of 19 V between the terminals of the solid electrolytic capacitor thus manufactured in a 105 ° C. atmosphere for 1 hour.

(Embodiment 2) In Embodiment 1, 2- (perfluoroalkenyloxy) ethyl acrylate and perfluoroalkenyl to which a film-forming modifier is added instead of a 3% by weight solution of fluororesin in bistrifluoroxylene. Embodiment 1 is the same as Embodiment 1 except that a mixed solvent solution containing bistrifluoroxylene and para-xylene hexafluoride of a fluororesin containing a graft copolymer with polyvinyl phenyl ether (concentration of the fluororesin is 2% by weight) is used. It was produced similarly. The thickness of the fluororesin was 0.3 to 0.7 μm as a result of observation with an electron microscope.
m. The surface tension of the coating layer was 17 mN / m.

(Embodiment 3) Embodiment 1 is different from Embodiment 1 in that a 2% by weight hydrofluoroether solution of a fluororesin is used in place of the 3% by weight bistrifluoroxylene solution of the fluororesin. It was produced similarly. The thickness of the fluororesin was 0.5 to 1.0 μm as observed by an electron microscope. The surface tension of the coating layer was 11 mN / m.

Comparative Example 1 In the first embodiment,
The fabrication was performed in the same manner as in Embodiment 1 except that the aluminum portion of the aluminum electrode tab to which the lead terminal was welded was not treated.

With respect to the solid electrolytic capacitors of Embodiments 1 to 3 of the present invention and Comparative Example 1 manufactured as described above, their capacitance (measuring frequency 120 Hz), ESR (measuring frequency 100 kHz), leakage current (rated voltage) After applying 16V 2
Value) and reflow soldering (peak temperature 250
(Table 1) shows the result of comparing the leakage currents after the exposure to 45 ° C. and 200 ° C. or more. The number of test pieces was 50 and the characteristic values were all average values.

[0043]

[Table 1]

As is clear from Table 1, the solid electrolytic capacitors according to the first to third embodiments of the present invention have a smaller leakage current than the solid electrolytic capacitors of the comparative examples, and have a smaller leakage current after the reflow soldering process. It can be seen that there is little change in leakage current and a highly reliable solid electrolytic capacitor can be constructed.

Further, the adhesion of the polymer to the electrode tab portion is remarkably small due to the effect of lowering the wettability, and the soldering is inhibited due to these (the polymer covers the terminal portion and the tin plating layer of the lead-out lead to lower the solder wettability. There is no need to worry about poor soldering).

[0046]

As described above, according to the present invention, at least a part of the electrode tab for leading out the lead terminal is treated to reduce the wettability to a conductive polymer or the like, so that the leakage current is reduced. The conductive polymer or the like hardly adheres during polymerization to the electrode tab portion electrically connected to the anode foil, which is a portion that is particularly likely to become large (wetting property lowering effect). For this reason, the adhesion of the conductive polymer acting as the cathode body to the electrode tab portion can be suppressed, and as a result, a solid electrolytic capacitor having a small leakage current can be formed by the blocking effect of the leakage current extraction portion. Can be.

As a manufacturing method for obtaining this solid electrolytic capacitor, at least a part of the electrode tab is coated with a resin for reducing the wettability to a conductive polymer or the like. And the step of vaporizing and dissipating the solvent component of the solution of the solvent-soluble resin, the coating process of the resin that reduces the wettability can be easily and uniformly performed. it can.

According to the present invention, it is possible to obtain a highly reliable solid electrolytic capacitor having a small leakage current and a small fluctuation in the leakage current even when subjected to thermal stress during soldering. It becomes.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional perspective view showing a configuration of a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 2A is a perspective view showing an electrode tab of a lead wire of the capacitor element. FIG.

[Explanation of symbols]

 Reference Signs List 1 anode foil 2 cathode foil 3 separator 4 capacitor element 5 anode lead 6 anode tab 7 cathode lead 8 cathode tab 9 aluminum case 10 sealing material 11 treatment layer for reducing wettability

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Akira Harada 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Ichiro Yamashita 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (12)

[Claims] 1. An electrode tab made of an aluminum wire having a flat portion, and a lead lead electrically connected to the electrode tab. At least a part of the electrode tab has polypyrrole, polyethylene dioxythiophene polystyrene sulfonic acid. , Polyethylenedioxythiophene, pyrrole, ethylenedioxythiophene, aliphatic sulfonic acid, toluenesulfonic acid, naphthalenesulfonic acid, anthraquinonesulfonic acid, styrenesulfonic acid, polystyrenesulfonic acid and derivatives of the above compounds, and methanol, ethanol, n- A lead wire for a capacitor, which has been subjected to a treatment for reducing wettability with respect to a mixture of at least one of propyl alcohol, isopropyl alcohol, n-butanol and water. 2. A process for reducing wettability applied to at least a part of an electrode tab is a resin coating process.
The lead wire for a capacitor according to the item. 3. The resin coated on at least a part of the electrode tab is 2- (perfluoroalkenyloxy) methyl acrylate or 2- (perfluoroalkenyloxy).
A double layer composed of at least one selected from the group consisting of ethyl acrylate, 2- (perfluoroalkyloxy) methyl acrylate, 2- (perfluoroalkyloxy) ethyl acrylate, perfluoroalkenyl polyvinyl phenyl ether, and perfluoroalkyl polyvinyl phenyl ether. The lead wire for a capacitor according to claim 2, wherein the lead wire is a resin made of united resin. 4. A resin coated on at least a part of the electrode tab is a resin containing at least one of a fluorine-containing resin, a silicon-containing resin, a titanium-containing resin and a resin having a surface tension of 30 mN / m or less in a coated state. The lead wire for a capacitor according to claim 2, which is any of a mixture. 5. The capacitor lead according to claim 2, wherein the resin coated on at least a part of the electrode tab is soluble in a fluorine-containing solvent and / or a chlorine-containing solvent. 6. The resin coated on at least a part of the electrode tab is polyfluoroether, hydrofluoroether, methyl perfluoroether isobutyl ether, methyl perfluorobutyl ether, fluorobenzene, trifluoromethylbenzene, bistrifluoromethylbenzene. 6. A fluorine-containing resin which is soluble in at least 20.1% by weight of a mixed fluorine-containing solvent of at least one of xylene, hexafluoride, hexafluoropropene, and derivatives and / or multimers thereof. Lead wire for capacitors. 7. A strip-shaped anode foil and a cathode foil to which the capacitor lead wires according to claim 1 are respectively electrically connected are wound with a separator interposed therebetween. A solid electrolytic capacitor comprising the formed capacitor element and a conductive polymer solid electrolyte filled in the capacitor element. 8. The solid electrolytic capacitor according to claim 7, wherein the conductive polymer is at least one of polypyrrole, polyethylene dioxythiophene polystyrene sulfonic acid, polyethylene dioxythiophene, and a derivative of the above compound. 9. The solid electrolytic capacitor according to claim 7, wherein the repeating unit monomer constituting the conductive polymer is at least one of pyrrole, ethylenedioxythiophene, and a derivative of the compound. 10. The dopant constituting the conductive polymer and its compound are any of aliphatic sulfonic acid, toluenesulfonic acid, naphthalenesulfonic acid, anthraquinonesulfonic acid, styrenesulfonic acid, polystyrenesulfonic acid and derivatives of the above compounds. The solid electrolytic capacitor according to claim 7, wherein 11. A polymerization solvent used for filling the conductive polymer is a mixed solvent containing methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, water and at least one of the above solvents. The solid electrolytic capacitor according to claim 7. 12. A step of forming a capacitor element by winding a strip-shaped anode foil and a cathode foil, each of which is electrically connected to an electrode tab for leading a lead terminal, with a separator interposed therebetween, A conductive polymer, a repeating unit monomer forming the conductive polymer, a dopant forming the conductive polymer and a compound thereof, a solvent used for filling the conductive polymer, and a conductive polymer in at least a part of the tab An oxidizing agent and a compound used for filling the conductive polymer, a step of coating a resin that reduces the wettability with respect to a mixture of at least one or more of the organic additive and the substance used for filling the conductive polymer; and A method for producing a solid electrolytic capacitor comprising a step of filling a solid electrolyte made of a conductive polymer into an element, wherein the resin is coated with a resin. A method for producing a solid electrolytic capacitor, comprising: a step of adhering a solution of a solvent-soluble resin to at least a part of an electrode tab; and a step of vaporizing and dissipating a solvent component of the solution of a solvent-soluble resin.