JP2902429B2 - Solid electrolytic capacitors - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrolytic capacitor using a conductive polymer film such as polypyrrole as a solid electrolyte.

2. Description of the Related Art In a conventional electrolytic capacitor using a conductive polymer film such as polypyrrole as a solid electrolyte, a dielectric film is formed on a film-forming metal foil which has been roughened in advance, and a metal film having the dielectric film formed thereon is formed. After forming a chemically oxidized and polymerized conductive polymer film such as pyrrole, thiophene, aniline, or furan on the dielectric film of the electrode body formed by connecting a smooth metal as an extraction terminal, using an oxidizing agent, Forming an electropolymerized conductive polymer film on a chemically oxidized polymerized conductive polymer film,
A solid electrolytic capacitor is configured.

Problems to be Solved by the Invention The solid electrolytic capacitor described above has the following problems in forming a chemically oxidized and polymerized conductive polymer film, and has not been put to practical use.

That is, the chemically oxidized polymerized conductive polymer film immerses the electrode body in a monomer such as pyrrole, thiophene, aniline, or furan or a solution thereof, and then contacts the oxidant, or conversely, immerses the electrode body in a solution of the oxidant, By contacting with a monomer such as pyrrole, thiophene, aniline, or furan or a solution thereof, a chemically oxidized and polymerized conductive polymer film is formed on the electrode body, but a dielectric film is formed on the roughened film-forming metal foil. In the case of the former chemical oxidative polymerization method, the formed electrode part can hold a monomer or a solution thereof in the case of the former chemical oxidative polymerization method, and in the case of the latter chemical oxidative polymerization method, it can hold a solution of the oxidizing agent, respectively. In the case of the following chemical oxidative polymerization method, the oxidizing agent is brought into contact with a solution of the oxidizing agent, and in the case of the latter chemical oxidative polymerization method, the monomer or its solution is brought into contact with the chemical weight. Although the conductive polymer film can be uniformly formed with a constant thickness, the surface connected to the electrode as the lead terminal has a smooth surface state, so it is difficult to hold the respective liquids, and the lead terminal is formed on the lead terminal. Does not form a chemically polymerized conductive polymer film or only very non-uniformly forms a chemically polymerized conductive polymer film. In the case of manufacturing a capacitor, there has been a problem that a fatal defect such as a short circuit or a large wetting current occurs.

Means for Solving the Problems The present invention has solved the above-mentioned problems, in which a dielectric film is formed on a film-forming metal foil which has been roughened in advance, and the metal on which the dielectric film has been formed is added to hot water. Using an oxidizing agent, a chemically oxidized polymerized conductive polymer film of pyrrole, thiophene, aniline, and furan is formed on the dielectric film of the electrode body formed by connecting an aluminum plate, which has produced aluminum hydroxide, as an extraction terminal. Is formed, and electrolytically polymerized thereon is laminated with an electropolymerized conductive polymer film to provide a solid electrolytic capacitor.

Effect In the solid electrolytic capacitor of the present invention, an aluminum plate in which aluminum hydroxide is previously generated in hot water is used as a lead terminal connected to a film-forming metal foil on which a dielectric film has been formed in advance. When an aluminum hydroxide is generated in hot water using the water oxidation algorithm, aluminum hydroxide with whisker-like irregularities is generated on the aluminum surface. Because it can be held, a chemically oxidized and polymerized conductive polymer film of pyrrole, thiophene, aniline, furan, etc. can be uniformly formed on the lead-out terminal. Examples Possible Examples Hereinafter, examples based on the present invention and comparative examples for comparison will be described.

(Example-1) An aluminum foil on which a dielectric film equivalent to a withstand voltage of 25 V was formed was used as an anode (sample area: 3 mm x 10 mm) and immersed in pure water at 100 ° C for 15 minutes to produce aluminum hydroxide. The aluminum tab was connected to the anode, and the cut portion was subjected to a chemical conversion treatment at a voltage between electrodes of 21 V.
After being immersed in an aqueous solution of 1 liter, it was immersed in an acetonitrile solution containing 3 mol / l of a pyrrole monomer for 20 minutes to form a chemically oxidized polymer film. Further, the electrode is a pyrrole monomer
In acetonitrile solution containing 0.02 mol / l, 0.05 mol / l tetrabutylammonium toluenesulfonate as a supporting electrolyte, using a stainless steel plate as a cathode, perform 0.5 mA, electropolymerization for 150 minutes, and electropolymerize polypyrrole on the chemically polymerized oxide film. Was formed by lamination. Further, a carbon layer was formed on the surface, a counter electrode lead was attached using a silver paste, and the package was made using an epoxy resin to make a capacitor. The characteristics of this capacitor are shown in Table 1 as Example-1.

(Example-2) As Example-2, the aluminum tub, which was immersed in pure water at 90 ° C for 30 minutes to form aluminum hydroxide, was subjected to a chemical conversion treatment in 10 wt% ammonium adipate at a voltage between electrodes of 50V. After that, the capacitor was connected to the anode and manufactured in the same manner as in Example-1. The characteristics of this capacitor are shown in Table 1 as Example-2.

Comparative Example 1 As Comparative Example 1, a smooth aluminum tab was connected to the anode foil, and then a capacitor was manufactured in the same manner as in Example 1. The characteristics of this capacitor are shown in Table 1 as Comparative Example-1.

(Comparative Example-2) As Comparative Example-2, a smooth aluminum turnip was subjected to a chemical conversion treatment in a 10 wt% ammonium adipate at a voltage between electrodes of 50 V, and then connected to the anode. A capacitor was manufactured by the method. The characteristics of this capacitor are shown in Table 1 as Comparative Example-2.

In addition, the non-defective product ratio was determined as a short product as a defect, and each characteristic value was determined from the non-defective product.

As described above, as shown in Table 1, the examples according to the present invention showed good results in terms of non-defective products and various characteristics. In particular, it shows a remarkable effect on the yield rate and wetting current. Further, it has been confirmed that further processing such as formation of a tab portion in the present invention further contributes to improvement in aspects such as wetting current. In addition, the same result was obtained by using the above-described other conductive polymer without being limited to the present example. further,
In the structure of the capacitor, the same result was obtained in both the single plate and the wound electrode structure.

The conditions for forming aluminum hydroxide on the tab portion are not limited to pure water, and the effect has been confirmed even when aluminum hydroxide is formed using a solution obtained by adding an additive or the like to pure water.

Effect of the Invention As described above, a dielectric film is formed on a film-forming metal foil which has been previously roughened, and the metal on which the dielectric film has been formed is previously formed with aluminum hydroxide in hot water. An oxidizing agent is used to form a chemically oxidized and polymerized conductive polymer film of pyrrole, thiophene, aniline, furan, etc. on the dielectric film of the electrode body formed by connecting the plate as a lead terminal, and electrolytic polymerization is performed thereon. A solid electrolytic capacitor characterized by laminating an electropolymerized conductive polymer film on the other hand exhibits stable characteristics as an electronic component, and has great industrial and practical value.

────────────────────────────────────────────────── ─── Continued from the front page Examiner Koji Osawa (56) References JP-A-1-268111 (JP, A) JP-A-1-105523 (JP, A) (58) Fields investigated (Int. Cl. ⁶⁾ , DB name) H01G 9/028 H01G 9/012

Claims (1)

(57) [Claims] 1. A dielectric film is formed on a film-forming metal foil which has been roughened in advance, and an aluminum plate which has been previously formed with aluminum hydroxide in hot water is drawn from the metal on which the dielectric film has been formed. An oxidizing agent is used to form a chemically oxidized and polymerized conductive polymer film of pyrrole, thiophene, aniline, and furan on the dielectric film of the electrode body connected as a terminal, and electrolytic polymerization is performed on the conductive polymer film. A solid electrolytic capacitor characterized by laminating conductive polymer films.