WO2006118144A1

WO2006118144A1 - Solid state electrolytic capacitor and method for producing the same

Info

Publication number: WO2006118144A1
Application number: PCT/JP2006/308733
Authority: WO
Inventors: Masahiro Kuroyanagi
Original assignee: Showa Denko K.K.
Priority date: 2005-04-27
Filing date: 2006-04-26
Publication date: 2006-11-09

Abstract

A solid state electrolytic capacitor being formed by laying planar capacitor elements in layers wherein moisture resistance is enhanced, leak current is reduced and equivalent series resistance is decreased. An anodized film is provided on the surface of a planar metal having valve action, a portion applied with an insulating resin band (masking) is provided to divide the metal into two, one of two divided metals serves as an anode portion and a solid state electrolytic layer is provided on the surface of the remaining portion. Furthermore, a conductor layer is provided on the solid state electrolytic layer to obtain a capacitor element, and a plurality of capacitor elements are stacked such that the conductor layer and the anode portion correspond to each other, which is then connected with the cathode lead and anode lead of a lead frame, a small quantity of silicon oil is added to the capacitor element and dried, and then the resultant product is sealed with coating resin such as epoxy resin, thus attaining a solid state electrolytic capacitor exhibiting extremely excellent electric characteristics and long term reliability.

Description

Specification

Solid electrolytic capacitor and manufacturing method thereof

Relationship with related applications

[0001] This application is subject to the benefit of the filing date of US Provisional Application No. 60Z677,353 filed May 4, 2005, in accordance with the provisions of 35 USC 111 (b), US Code. This is an application based on the provisions of Article 111 (a) claimed in Article 119 (e) (1).

Technical field

The present invention relates to a solid electrolytic capacitor and a method for manufacturing the same. More specifically, in a solid electrolytic capacitor in which a valve metal substrate having a dielectric film is laminated, the solid electrolytic capacitor having good moisture resistance, low leakage current and reduced equivalent series resistance, and its manufacture Regarding the method.

Background art

[0003] Recently, electronic devices have become smaller and higher in frequency, and solid electrolytic capacitors, which are a type of electronic component used for such devices, are required to be smaller. S, generally a multilayer chip shape. To meet the demand for miniaturization.

The example shown in FIG. 1 is a perspective view of a conventional chip-shaped multilayer solid electrolytic capacitor in which two capacitor elements are laminated. Capacitor elements 11 and 12 inside the exterior resin 16 are arranged with their directions aligned, and the cathode part 11a of the capacitor element 11 is joined to the cathode lead part 13 with a conductive adhesive, and the cathode of the capacitor element 12 The part 12a is joined to the cathode part 11a of the capacitor element 11 by a conductive adhesive, and the anode parts l lb and 12b of the capacitor elements 11 and 12 are joined by resistance welding at the joint part 15 to the anode lead part 14. It is sealed with a separately prepared exterior resin 16 such as an epoxy resin.

[0005] As a metal having a valve action used for a capacitor element of a solid electrolytic capacitor, a metal such as aluminum tantalum which can be easily provided with a dielectric film is used. Metals that can be easily provided with a dielectric film on these surfaces may have a property of absorbing moisture in the air. The solid electrolyte layer provided on the dielectric film is a spongy layer having fine pores, which also absorbs moisture in the air. That is, the capacitor element is made of a material that easily absorbs moisture. In the case of a 220 capacitor with a withstand voltage of 2 V, the moisture content in the capacitor element reaches several hundred ng. Moisture contained in this capacitor element has an adverse effect on the electrical characteristics of the solid electrolytic capacitor and also causes deterioration of long-term reliability such as moisture resistance.

[0006] Conventionally, moisture contained in the capacitor element was evaporated by heating the capacitor element before sealing with an exterior resin such as epoxy resin. However, after heating, the moisture in the air is rapidly absorbed. As a result, the amount of moisture contained in the capacitor element could not be greatly reduced.

[0007] If sealing can be performed while the capacitor element is heated, it is possible to reduce the amount of water contained in the capacitor element. It is necessary to remodel the sealing device. Such modifications are very expensive. Therefore, it is difficult to seal the capacitor element while it is heated.

[0008] After sealing with an exterior resin such as an epoxy resin, it is possible to reduce the moisture contained in the capacitor element by drying the solid electrolytic capacitor, but the exterior resin force S covering the capacitor element Therefore, drying takes a very long time and is not a realistic solution.

JP-A-2001-126964 (Patent Document 1) discloses that the space inside the pores of the capacitor element is filled with a hydrophobic solvent, or the surface of the space is covered with a hydrophobic solvent. Japanese Patent No. 126965 (Patent Document 2) proposes to coat the surface of the space with a water repellent film. In this case, the solid electrolyte layer existing outside the hydrophobic solvent or the water repellent film, It cannot prevent moisture absorption of the carbon layer and silver layer, and has no effect on moisture absorption of the anode part of the capacitor element.

That is, it has been known that the moisture contained in the capacitor element has an adverse effect on the long-term reliability of the solid electrolytic capacitor, such as the electrical characteristics and moisture resistance, but there is a practical means to solve this. I didn't.

Patent Document 1: Japanese Patent Laid-Open No. 2001-126964

Patent Document 2: Japanese Patent Laid-Open No. 2001_126965

Disclosure of the invention Problems to be solved by the invention

Accordingly, an object of the present invention is to solve the above-described problems and provide a solid electrolytic capacitor excellent in long-term reliability such as electric characteristics and moisture resistance characteristics and a method for manufacturing the same. Means for solving the problem

[0013] As a result of diligent research to solve the above-mentioned problems, the present inventors have found that the present invention simply uses a water-repellent material, particularly silicone oil, in a capacitor element without greatly changing the conventional method for producing a solid electrolytic capacitor. Adding a small amount to dry not only reduces the moisture contained in the capacitor element, but also remarkably slows the reabsorption of moisture to produce a solid electrolytic capacitor with excellent electrical characteristics and long-term reliability. And succeeded.

[0014] An anodized film is provided on the surface of a plate-like metal having a valve action, a portion provided with an insulating resin band (masking) is provided so as to bisect this metal, and one of the bisected metals is used as an anode part. In addition, a solid electrolyte layer is provided on the remaining surface, and a conductor layer is further provided on the solid electrolyte layer to form a capacitor element. Further, a plurality of connection portions of the conductor layer and the anode part correspond to each other. After connecting and stacking the capacitor elements to the cathode lead and anode lead parts of the lead frame, a small amount of water-repellent material, especially silicone oil, is added to the capacitor element and dried, followed by an exterior resin such as an epoxy resin. By carrying out the sealing with, a solid electrolytic capacitor having excellent electrical characteristics and long-term reliability can be obtained.

That is, the present invention provides the following solid electrolytic capacitor and manufacturing method thereof.

1. A solid electrolytic capacitor including a dielectric film layer, a solid electrolyte layer, and a conductor layer, characterized in that a solid electrolytic capacitor having a water-repellent film on all or part of the capacitor element surface including the surface of the conductor layer Capacitor.

2.Solid electrolysis with a part of the valve metal having a dielectric film layer on the surface as the anode part, a solid electrolyte layer on the remaining dielectric film layer, and a conductor layer on it as the cathode part A solid electrolytic capacitor characterized in that the capacitor has a water-repellent coating on all or part of the surface of the capacitor element including the surface of the conductor layer. 3. A part of the valve metal having a dielectric film layer on the surface is used as an anode part, a solid electrolyte layer is formed on the remaining dielectric film layer, and a conductor layer is formed on a part of the solid electrolyte layer. A solid electrolytic capacitor in which anode parts and cathode parts of a plurality of capacitor elements are respectively stacked and connected to a lead frame and sealed with an exterior resin, the capacitor element surface including a conductor layer surface A solid electrolytic capacitor characterized by having a water-repellent film on all or part of the capacitor.

4. The solid electrolytic capacitor as described in any one of 1 to 3 above, wherein the conductor layer includes a carbon paste layer and a silver paste layer, and at least a part of the capacitor element surface including the carbon paste layer has a water-repellent film. .

5. The solid electrolytic capacitor as described in any one of 1 to 4 above, wherein the water-repellent film is a film containing silicone oil.

6. The solid electric early capacitor as described in 5 above, wherein the viscosity of the silicone oil is 5 mPa ′ second to 500 mPa ′ second.

7. The solid electrolytic capacitor as described in 5 above, wherein the silicone oil is straight silicone oil.

8. The solid electrolytic capacitor as described in 7 above, wherein the silicone oil is dialkyl silicone, alkyl aryl silicone, or alkyl hydrogen silicone.

9. The solid electrolytic capacitor as described in 8 above, wherein the dialkyl silicone is dimethyl silicone.

10. The solid electrolytic capacitor as described in 8 above, which is alkylaryl silicone alkyl phenyl silicone.

11. The solid electrolytic capacitor as described in 8 above, wherein the alkyl hydrogen silicone is methyl hydrogen silicone.

12. The solid electrolytic capacitor as described in 5 above, wherein the silicone oil is a modified silicone oil.

13. A solid electrolytic capacitor comprising a step of providing a dielectric film layer, a solid electrolyte layer and a conductor layer on an anode substrate, and then covering all or part of the capacitor element surface including the conductor layer surface with a water repellent film Manufacturing method. 14. A part of the valve metal having a dielectric coating layer on the surface is used as an anode portion, a solid electrolyte layer is formed on the remaining dielectric coating layer, and a conductive layer is provided thereon. A method for producing a solid electrolytic capacitor, comprising a step of covering all or part of a capacitor element surface including a surface with a water-repellent film.

15. A portion of the valve metal having a dielectric coating layer on the surface is used as the anode portion, a solid electrolyte layer is formed on the remaining dielectric coating layer, and a conductor layer is formed on a part of the solid electrolyte layer to form a cathode portion. Laminate the anode and cathode of multiple capacitor elements and connect them to the lead frame.

In a method for manufacturing a laminated solid electrolytic capacitor including a step of sealing and molding with an exterior resin, all or part of the capacitor element surface including the conductor layer surface at any time after the conductor layer is formed and before sealing. A method for producing a solid electrolytic capacitor, comprising a step of coating with a water repellent film.

16. The method for producing a solid electrolytic capacitor as described in any one of 13 to 15 above, wherein the water repellent film is a film containing silicone oil. The invention's effect

Thus, by adding a water repellent material, particularly silicone oil, to the capacitor element, a solid electrolytic capacitor having excellent electrical characteristics can be obtained.

BEST MODE FOR CARRYING OUT THE INVENTION

[0017] Hereinafter, the present invention will be described in detail.

(Valve action metal)

As the valve action metal used as the anode substrate of the solid electrolytic capacitor in the present invention, for example, aluminum, tantalum, titanium, niobium, zirconium and alloys based on these can be used. Examples of the shape of the anode substrate include a flat foil, a plate, and a rod. Of these, aluminum conversion foil is widely used because it is economical. This aluminum conversion foil is 40 to 200 zm thick, and a rectangular element having a flat and horizontal unit of about 1 to 30 mm in length and width is used. The width is preferably 2 to 20 mm and the length is 2 to 20 mm, more preferably the width is 2 to 5 mm and the length is 2 to 6 mm.

[0018] The dielectric coating layer provided on the surface of the anode substrate may be an oxide layer of the valve action metal itself provided on the surface portion of the valve action metal, or provided on the surface of the valve action metal foil. Although it may be another dielectric layer formed, it is desirable that it is a layer made of an oxide of the valve metal itself.

[0019] One section of the end portion of the flat plate-like anode substrate having a dielectric coating layer formed on the surface is defined as an anode portion, and the remaining portion is defined as a cathode portion. An insulating resin band (masking) may be used for the classification of the anode part and the cathode part.

[0020] (Solid electrolyte)

Next, a solid electrolyte is formed on the dielectric coating layer of the cathode part. There are no particular restrictions on the type of the solid electrolyte layer, and conventionally known solid electrolytes can be used. Compared to conventional wet electrolytic capacitors using electrolytic solutions and solid electrolytic capacitors using manganese dioxide, the solid electrolyte capacitors made with a solid electrolyte have a large capacity and a small size with a low equivalent series resistance component. Is preferable because it is good.

[0021] The conductive polymer forming the solid electrolyte used in the solid electrolytic capacitor of the present invention is not limited, but is preferably a conductive polymer having a π-electron conjugated structure, such as a compound having a thiophene skeleton, a polycyclic Examples thereof include conductive polymers containing as a repeating unit a structure represented by a compound having a sulfide skeleton, a compound having a pyrrole skeleton, a compound having a furan skeleton, or the like.

[0022] Among the monomers used as the raw material for the conductive polymer, compounds having a thiophene skeleton include, for example, 3-methylthiophene, 3-ethylthiophene, 3_propylthiophene, 3-butylthiophene, 3 _Pentylthiophene, 3_Hexylthiophene, 3_Heptylthiophene, 3-Octylthiophene, 3-Nonylthiophene, 3_Desinorethiophene, 3-Funoleolothiophene, 3_Chlorothiophene, 3-Bromothiophene, 3 —Syanthiophene, 3, 4_dimethylthiophene, 3, 4 _jetylthiophene, 3, 4-butyrenthiophene, 3,4_methylenedioxythiophene, 3, 4 _ethylenedioxythiophene Derivatives can be mentioned. These compounds can be prepared by commercially available compounds or known methods (for example, Synthetic Metals, 1986, 15 pages, 169 pages).

[0023] Further, for example, as a compound having a polycyclic sulfide skeleton, for example, 1,3-dihydro A compound having a dropolycyclic sulfide (also known as 1,3-dihydrobenzo [c] thiophene) skeleton and a compound having 1,3 dihydronaphtho [2,3_c] thiophene skeleton can be used. In addition, compounds having a 1,3-dihydroanthra [2,3_c] thiophene skeleton and compounds having a 1,3-dihydronaftaseno [2,3_c] thiophene skeleton can be exemplified, and known methods For example, it can be prepared by the method described in JP-A-8-3156 (US5530139).

[0024] Further, for example, a compound having a 1,3-dihydronaphtho [1,2_c] thiophene skeleton,

3 Dihydrophenanthra [2, 3-c] thiophene derivatives, 1,3 dihydrotriphe two-necked [2, 3 c] thiophene skeletons, 1,3-dihydrobenzo [a] anthraceno [7, 8-c] thiophene derivatives can also be used.

[0025] Some compounds optionally contain nitrogen or N-oxide in the fused ring, such as 1,3-dihydrothieno [3,4-b] quinoxaline, 1,3-dihydroceno [3,4-b] Powers that can include quinoxaline 4-oxide, 1,3-dihydroceno [3,4-b] quinoxaline-1,4,9 dioxide, and the like, but are not limited thereto.

[0026] Examples of the compound having a pyrrole skeleton include, for example, 3-methylpyrrole, 3-ethylpyrrolone, 3-propylpyrrole, 3-butylpyrrole, 3-pentylpyrrole, 3-hexylpyrrole, 3-heptylpyrrole. , 3-octylpyrrole, 3-nonylpyrrolone, 3_decenolepyrrolone, 3-funoleorone, 3_black pyrrole, 3_bromopyrrole, 3-cyanopyrrole, 3,4-dimethylpyrrole, Examples thereof include, but are not limited to, 3,4-jetylpyrrole, 3,4-butylenepyrrole, 3,4-methylenedioxypyrrole, and 3,4_ethylenedioxypyrrole. These compounds can be prepared commercially or by known methods.

[0027] Examples of the compound having a furan skeleton include, for example, 3 methinolefuran, 3-ethylfuran, 3-propylfuran, 3-butylfuran, 3-pentylfuran, 3-hexylfuran, 3_heptylfuran, 3 —Octylfuran, 3-Nonylfuran, 3_decylfuran, 3_Fluorofuran, 3_Black-furan, 3_Bromofuran, 3_Cyanofuran, 3,4-Dimethylfuran, 3,4-Jetinolefuran, 3,4-Butylenefuran, Force S, which includes derivatives such as 3, 4-methylenedioxyfuran, 3,4-ethylenedioxyfuran, etc. There is no. These compounds can be prepared commercially or by known methods.

[0028] The polymerization method may be electrolytic polymerization, chemical oxidative polymerization, or a combination thereof. Alternatively, a solid electrolyte that is not a conductive polymer is first formed on the dielectric film, and then a conductive polymer is formed by the above-described polymerization method.

[0029] As an example of forming a conductive polymer, 3, 4_ethylenedioxythiophene monomer and an oxidizer, preferably in the form of a solution, separately before and after or together on the dielectric film A method of forming by coating (Japanese Patent Laid-Open No. 2-15611 (US4910645) or Japanese Patent Laid-Open No. 10-32145) can be used.

[0030] Generally, a compound having a doping ability (dopant) is used for the conductive polymer, and the dopant can be added to either the monomer solution or the oxidant solution. It can be something like an organic sulfonic acid metal salt. As the dopant, an aryl sulfonate dopant is preferably used. For example, salts such as benzene sulfonic acid, toluene sulfonic acid, naphthalene sulfonic acid, anthracene sulfonic acid, anthraquinone sulfonic acid and the like can be used.

[0031] (Water-repellent coating)

On the solid electrolyte layer containing such a conductive polymer, for example, a conductive layer such as a carbon paste and / or a silver paste is applied to form a conductive layer to form a cathode portion (conductive layer forming portion) Configure. An insulating resin layer may be formed in a circumferential shape (cylinder shape) by an insulating resin band (masking) at a boundary portion between the anode portion and the cathode portion.

In the present invention, a water repellent film is formed on the capacitor element.

Specifically, in a solid electrolytic capacitor including a dielectric film layer, a solid electrolyte layer and a conductor layer, a water repellent film is formed on all or part of the capacitor element surface including the conductor layer surface. Preferably, a part of the valve action metal having a dielectric coating layer on the surface is used as an anode portion, a solid electrolyte layer is formed on the remaining dielectric coating layer, and a conductor layer is formed thereon to form a cathode portion. In the capacitor, a water repellent film is formed on all or part of the surface of the capacitor element including the surface of the conductor layer.

[0033] The water-repellent film may cover all or part of the surface of the capacitor element as long as the surface of the conductor layer is included. In addition, the conductor layer has a carbon paste layer and a silver When a part of the carbon paste layer is exposed in the case of including the strike layer, a water-repellent film is provided on all or part of the capacitor element surface including the carbon paste layer.

In the present invention, a water-repellent film is formed on the capacitor element laminated on the lead frame.

That is, the cathode part of the capacitor element is joined to the cathode lead part of the lead frame using a conductive adhesive, and the conductive adhesive is applied on the cathode part of the capacitor element to form the cathode part of the new capacitor element. Join with. On the other hand, the anode part of the capacitor element is connected to the anode lead part of the lead frame. The connection method may be a conventionally known method such as resistance welding, laser welding, ultrasonic welding, force squeeze, or adhesion using a conductive paste.

[0035] The water-repellent film may be any one having water repellency, such as oils such as mineral oil and chemically synthesized oil, and elastomers such as silicone rubber and fluorine rubber. Preferably, silicone oil is added. The added silicone oil covers the surfaces of the carbon paste conductor layer 21a and the silver paste conductor layer 21b at the cathode portion of the capacitor element as shown in FIG. 2, and the sponge-like solid electrolyte layer 22 and the air It penetrates the boundary and forms on the surface of the valve metal 23 and penetrates the boundary between the dielectric film 24 and the air, so that the silicone oil film 25 is formed between the outside and the cathode of the capacitor element 25. Is formed. The added silicone oil penetrates the boundary between the conductive adhesive 26 and the air to form a silicone oil film 25. Some of them may reach the cathode lead 27. The added silicone oil also forms a silicone oil film 25 at the boundary between the insulating resin band 28 and the air on the surface of the insulating resin band 28. In addition, the attached silicone oil permeates the boundary between the anode 29 and the air, regardless of the connection method used in the anode 29 of the capacitor element. A silicone oil film 25 is formed between the two. Some of them may reach the anode lead 30. The silicone oil film formed in this way functions to remarkably suppress the rate at which the capacitor element absorbs moisture from the air. After adding the silicone oil, the capacitor element stacked on the lead frame is dried to remove the moisture contained in the capacitor element and at the same time remove the moisture contained in the silicone oil. . After sealing molding with an exterior resin such as epoxy resin with a transfer molding machine, etc., the lead frame protrusions are cut in the vicinity of the capacitor element to form a chip-shaped solid electrolytic capacitor.

[0036] The part to which silicone oil is added is the anode part and / or the cathode part of the capacitor element. The addition method of silicone oil may be a known method such as spraying, dripping or coating. The amount of applied force is very small, and it is desirable to apply with a dispenser from the viewpoint of good repeatability at the position of addition. Silicone oil can be applied to the capacitor element either before or after the capacitor element laminated on the lead frame is dried, but in consideration of the effect of reducing the moisture contained in the silicone oil itself, silicone oil was added. It is desirable to dry the capacitor element later. Silicone oil can be added to the capacitor element either before or after the capacitor element is laminated on the lead frame. However, the silicone oil attenuates the adhesive force of the conductive adhesive used when laminating a plurality of capacitor elements. Therefore, it is desirable to add the silicone oil after laminating the capacitor element on the lead frame. Alternatively, the conductive layer of the capacitor element may be formed using a conductive paste preloaded with silicone oil, but a silicone oil film is formed on all of the boundary metal layer between the valve metal and the solid electrolyte layer and air. For this purpose, it is preferable to add silicone oil after the conductor layer is formed on the capacitor element. In addition, the capacitor element may be laminated on the lead frame using a conductive adhesive previously added with silicone oil, but the valve action metal and the solid electrolyte layer and the air boundary layer are all covered with silicone oil. In order to form a film, it is preferable to laminate a capacitor element on a lead frame using a conductive adhesive not containing silicone oil, and then add silicone oil to the capacitor element.

[0037] The type of silicone oil is not particularly limited, and includes conventional silicone oils such as straight silicone oil (unmodified silicone oil), modified silicone oil, and fluorosilicone oil.

[0038] Straight silicone oils include dialkyl silicones (dialkylpolysiloxanes), alkylaryl silicones (alkylaryl polysiloxanes), and alkyl hydrogen silicones (alkyl hydrogen polysiloxanes), where alkyl Examples of the group include lower alkyl groups such as methinole, ethyl and propyl, and examples of the aryl group include phenyl groups substituted with lower alkyl, halogen and the like. Preferred straight silicones include dimethyl silicone (dimethylpolysiloxane), methyl phenyl silicone, and methyl hydrogen silicone.

[0039] The modified silicone oil can be variously modified, in particular non-reactive modified. However, as long as the performance of the solid electrolytic capacitor is not adversely affected, the modified silicone oil may be used. For example, KF-868 manufactured by Shin-Etsu Chemical Co., Ltd. can be used.

[0040] When a silicone oil having a viscosity greater than lPa 'seconds is used, it takes a long time force S to penetrate into the capacitor element, and the viscosity is smaller than ImPa' seconds. Since the silicone oil contains volatile components and may not be suitable for the present invention, it may be ImPa 'seconds to lPa' seconds (including upper and lower limits; the same shall apply hereinafter unless otherwise specified). It is preferable to do this.

[0041] When a plurality of capacitor elements are stacked on the lead frame, silicone oil is permeated into the capacitor element of the intermediate layer by capillary action by adding silicone oil to the outermost capacitor element. The viscosity of is preferably 5 mPa 'seconds to 50 OmPa' seconds, more preferably 20 mPa * seconds to 40 OmPa 'seconds, more preferably lOmPa' seconds to 400 mPa 'seconds.

[0042] (Lead frame)

The lead frame material is not particularly limited as long as it is generally used, but is preferably copper-based (for example, Cu-Ni-based, Cu-Ag-based, Cu_Sn-based, Cu-Fe-based, Cu-Ni--). (Ag-based, Cu_Ni_Sn-based, Cu_Co_P-based, Cu_Zn_Mg-based, Cu_Sn_Ni_P-based alloys, etc.) The effects of improving the chamfering workability of the steel can be obtained.

Example

[0043] Hereinafter, representative examples of the present invention will be shown and more specifically described. Note that these are merely illustrative examples, and the present invention is not limited thereto. [0044] (Example 1)

As shown in FIG. 3, aluminum conversion foil 31 (manufactured by Nihon Densetsu Kogyo Co., Ltd., foil type 110 LJB22B, rated film withstand voltage: 4 vf) (hereinafter referred to as conversion foil) is divided into two from the tip. Masking material 32 (heat-resistant resin) with a width of 1 mm was formed on both sides and both ends of 31. The cathode 33 is divided into the cathode 33 and anode 34, and the cathode 33, which is the tip side section of this chemical conversion foil, is used as the electrolyte with 10% by weight aqueous solution of ammonium adipate, temperature 55 ° C, voltage 4V, current density 5mA. It was formed under conditions of / cm ² and energization time of 10 minutes, and washed with water. After that, the cathode part was immersed in isopropyl alcohol solution lmol / 1 of 3,4-ethylenedioxythiophene and allowed to stand for 2 minutes. Then, an oxidizing agent (ammonium persulfate: 1.5 mol / l) and a dopant ( It was immersed in a mixed aqueous solution of sodium naphthalene 2-sodium sulfonate: 0.15 mol / l) and allowed to stand at 45 ° C. for 5 minutes for oxidative polymerization. This impregnation step and polymerization step were repeated 12 times in total to form a solid electrolyte layer containing the dopant in the micropores of the chemical conversion foil. The conversion foil on which the solid electrolyte layer containing this dopant was formed was washed in 50 ° C warm water to form a solid electrolyte layer. After forming the solid electrolyte layer, use a 10% by weight aqueous solution of ammonium adipate as the electrolyte, re-formify under conditions of temperature 55 ° C, voltage 4 V, current density 5 mA / cm ² , energization time 10 minutes, and rinse with water. Thereafter, drying was performed at 100 ° C for 30 minutes. A carbon paste and a silver paste were sequentially coated thereon to form a conductor layer.

FIG. 4 shows a state in which four capacitor elements 41, 42, 43, 44 are laminated on the lead frame. The cathode part 42a of the capacitor element 42 is joined to the front side of the cathode lead part 45 by using silver paste, and the cathode part 43a of the capacitor element 43 is joined to the back side of the cathode lead part 45 by using silver paste. The cathode part 41a of 41 is joined to the front side of the cathode part 42a of the capacitor element 42 using silver paste, and the cathode part 44a of the capacitor element 44 is joined to the back side of the cathode part 43a of the capacitor element 43 and silver paste. And joined. The anode capacitors B41b, 42b, 43b, and 44b of the laminated capacitor elements 41, 42, 43, and 44 were joined to the anode lead rod by spot welding. A small amount of silicone oil (dimethyl silicone oil KF96-50cs, manufactured by Shin-Etsu Chemical Co., Ltd.) with a viscosity of 50 mPa's is applied to the cathode part 41a of the capacitor element 41 and the cathode part 44a of the capacitor element 44 laminated on the lead frame. Add 2 Resin sealing after drying for 3 hours at 00 ° C, and applying a voltage of 2.5V for 45 minutes in an environment of 135 ° C, rated capacity 220 x F with a structure in which four capacitor elements are stacked 50 solid electrolytic capacitors with a rated voltage of 2 V were obtained. Table 1 shows the results of measuring the leakage current and equivalent series resistance of the 50 solid electrolytic capacitors obtained in this way by soldering them onto the substrate using a 250 ° C reflow oven.

[Example 2]

Example 1 with the exception that the parts to which silicone oil is added are the cathode part 41a of the capacitor element 41, the cathode part 44a of the capacitor element 44, the anode part 41b of the capacitor element 41, and the anode part 44b of the capacitor element 44. Similarly, 50 solid electrolytic capacitors with a rated capacity of 220 μF and a rated voltage of 2 V were obtained. Table 1 shows the results of soldering 50 solid electrolytic capacitors obtained in this way onto a substrate using a 250 ° C reflow oven and measuring the leakage current and equivalent series resistance.

[0047] (Example 3)

A solid electrolytic capacitor with a rated capacity of 220 x F and a rated voltage of 2 V was used in the same manner as in Example 1 except that the silicone oil was changed to one with a viscosity of lOOmPa's (made by Shin-Etsu Chemical Co., Ltd., dimethyl silicone oil KF96—lOOcs). I got it. The 50 solid electrolytic capacitors obtained in this way are soldered on a substrate using a 250 ° C reflow oven, and the results of measuring leakage current and equivalent series resistance are shown in Table 1.

[0048] (Comparative Example 1)

50 solid electrolytic capacitors having a rated capacity of 220 μF and a rated voltage of 2 V were obtained in the same manner as in Example 1 except that no silicone oil was added. Table 1 shows the results of measuring the leakage current and equivalent series resistance of the 50 solid electrolytic capacitors obtained in this way by soldering them onto the substrate using a 250 ° C reflow oven.

Each example and comparative example are average values of 50 solid electrolytic capacitors.

[0049] [Table 1] Equivalent series resistance

(μ A) (mQ) Example 1 0. 37 2.5 Example 2 0. 33 2. 2 Example 3 0. 29 3. 0 Comparative Example 1 0. 48 3. 7

(Examples 4 to 9, Comparative Example 2)

The silicone oil to be added is shown in Table 2 (Shin-Etsu Chemical Co., Ltd., KF54, KF-99, KF-868, KF-96), and the other methods are the same as in Example 2 (Example 7 is carried out) In the same way as in Example 1, 50 solid electrolytic capacitors with a rated capacity of 220 μF and a rated voltage of 2 V were obtained.

For these capacitors, leakage current was measured after standing for 500 hours at 60 ° C and 90% RH. The average value is shown in Table 2.

[Table 2]

Varieties of added silicone oil

(β Α)

Methyl phenyl silicone

Example 4 (Shin-Etsu Chemical Co., Ltd., KF54) 3.5

Viscosity 400mPa.second

Methinole hydrogen silicone

Example 5 (Shin-Etsu Chemical Co., Ltd., KF99) 2.6

Viscosity 20mPa * sec

Amino modified silicone

Example 6 (Shin-Etsu Chemical Co., Ltd., KF-868) 4.0

Viscosity 90mPa-second

Dimethylol silicone

Example 7 (Shin-Etsu Chemical Co., Ltd., KF96-50cs) 3.0

Viscosity 50mPa-second

Dimethylol silicone

Example 8 (Shin-Etsu Chemical Co., Ltd., KF-96L-0.65cs) 10. 1

Viscosity 0.65mPa * sec

Dimethyl silicone

Example 9 (Shin-Etsu Chemical Co., Ltd., KF-96-3000cs) 8.5

Viscosity 3Pa * sec

Comparative Example 2 No additive 20. 2

Industrial applicability

[0051] Since the capacitor element according to the present invention has excellent moisture resistance and little change in electrical characteristics over time, it can be used in a wide range of fields such as home appliances, computers, in-vehicle parts, and industrial equipment.

Brief Description of Drawings

FIG. 1 is a perspective view showing a conventional multilayer solid electrolytic capacitor element.

FIG. 2 is a cross-sectional view illustrating one embodiment of the present invention.

FIG. 3 is a plan view showing an example of a capacitor element according to the present invention.

FIG. 4 is a perspective view showing an example of stacking capacitor elements in the present invention.

Explanation of symbols

[0053] 11 Capacitor element 1

11a Cathode element of capacitor element 1 l ib Anode part of capacitor element 2

12 Capacitor element 2

12a Capacitor element 2 cathode

12b Capacitor element 2 anode

13 Cathode lead

14 Anode lead

15 Anode joint

16 Exterior resin

21a Conductor layer of carbon paste

21b Silver paste conductor layer

22 Solid electrolyte layer

23 Valve metal

24 Dielectric coating

25 Silicone oil film

26 Conductive adhesive

27 Cathode lead

28 Insulating resin strip

29 Anode section

30 Anode lead

31 Aluminum conversion foil

32 Masking material (heat resistant resin)

33 Cathode

34 Anode section

1 Capacitor element 1

1a Capacitor element 1 cathode part 1b Capacitor element 1 anode part 2 Capacitor element 2

2a Capacitor element 2 cathode b Capacitor element 2 anode part Capacitor element 3a Capacitor element 3 cathode part b Capacitor element 3 anode part Capacitor element 4a Capacitor element 4 cathode part b Capacitor element 4 anode part Cathode lead part

Anode lead

Claims

The scope of the claims

[1] In a solid electrolytic capacitor including a dielectric film layer, a solid electrolyte layer, and a conductor layer, the solid having a water-repellent film on all or part of the capacitor element surface including the surface of the conductor layer Electrolytic capacitor.

[2] A solid having a part of the valve metal having a dielectric film layer on the surface as an anode part, a solid electrolyte layer on the remaining dielectric film layer, and a conductor layer on the solid electrolyte layer to form a cathode part A solid electrolytic capacitor characterized in that the electrolytic capacitor has a water-repellent coating on all or part of the surface of the capacitor element including the surface of the conductor layer.

[3] A part of the valve metal having a dielectric film layer on the surface is used as an anode part, a solid electrolyte layer is formed on the remaining dielectric film layer, and a conductor layer is formed on a part of the solid electrolyte layer. A solid electrolytic capacitor in which the anode part and cathode part of a plurality of capacitor elements are laminated and connected to a lead frame and sealed with an exterior resin, the capacitor element including a conductor layer surface A solid electrolytic capacitor characterized by having a water-repellent film on all or part of its surface.

[4] The solid electrolyte according to any one of claims 1 to 3, wherein the conductor layer includes a carbon paste layer and a silver paste layer, and has a water-repellent coating on all or part of the capacitor element surface including at least the carbon paste layer. Capacitor.

[5] The solid electrolytic capacitor according to any one of [1] to [4], wherein the water-repellent film is a film containing silicone oil.

6. The solid electrolytic capacitor according to claim 5, wherein the viscosity of the silicone oil is 5 mPa ′ second to 500 mPa ′ second.

7. The solid electrolytic capacitor according to claim 5, wherein the silicone oil is a straight silicone oil.

8. The solid electrolytic capacitor according to claim 7, wherein the silicone oil is a dialkyl silicone, an alkyl aryl silicone, or an alkylene kiln rhogen silicone.

9. The solid electrolytic capacitor according to claim 8, wherein the dialkyl silicone is dimethyl silicone.

[10] The alkylaryl silicone power of claim 8, which is S-methylphenyl silicone. Body electrolytic capacitor.

[11] The solid electrolytic capacitor as described in [8], which is an alkyl hydrogen silicone cation hydrogen silicone.

12. The solid electrolytic capacitor according to claim 5, wherein the silicone oil is a modified silicone oil.

[13] Solid electrolysis comprising a step of coating a dielectric film layer, a solid electrolyte layer and a conductor layer on an anode substrate, and then covering all or part of the capacitor element surface including the surface of the conductor layer with a water repellent film Capacitor manufacturing method.

[14] A part of the valve metal having a dielectric coating layer on the surface is used as an anode portion, a solid electrolyte layer is formed on the remaining dielectric coating layer, and a conductive layer is provided thereon. A method for producing a solid electrolytic capacitor comprising a step of covering all or part of a capacitor element surface including a body layer surface with a water-repellent film.

[15] A part of the valve metal having a dielectric film layer on the surface is used as an anode part, a solid electrolyte layer is formed on the remaining dielectric film layer, and a conductor layer is formed on a part of the solid electrolyte layer. In the method for manufacturing a laminated solid electrolytic capacitor, the anode part and the cathode part of the plurality of capacitor elements are stacked, connected to a lead frame, and sealed with an exterior resin. A method for producing a solid electrolytic capacitor, comprising a step of covering all or part of the surface of a capacitor element including the surface of a conductor layer with a water-repellent coating at any time before stopping.

[16] The method for producing a solid electrolytic capacitor as described in any one of [13] to [15], wherein the water-repellent film is a film containing silicone oil.