JPH0376209A - Aluminum solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To prevent exfoliation and coming off of a conductive polymer film by a method wherein an aluminum tab is connected to anode foil which is cut in prescribed width, and the aluminum tab is wound together with a separator having the width narrower than the anode foil. CONSTITUTION:An oxide film is formed on metal foil which is mainly composed of aluminum, the surface of which is roughened in advance, and an aluminum tab is connected to the anode foil which is cut in prescribed width, and the above- mentioned oxide film is wound and reformed together with a separator having the width narrower than the anode foil. A chemical oxide polymerization conductive polymer film, such as pyrrole, thiophene, aniline, furan and the like, and an electrolytic polymerization conductive polymer film are formed on the above-mentioned oxide film. As a capacitor is formed by winding the anode foil, which is used on the electrode, together with the separator having the width narrower than the cut anode foil and also as an oxidizing agent, monomer solution and polymer liquid for electrolytic polymerization are infiltrated into the surface of the electrode, a solid electrolyte can be formed after a capacitor element is formed. As a result, the yield of production of an aluminum solid electrolytic capacitor can be improved remarkably, and a leakage current can also be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an aluminum solid electrolytic cone capacitor using a conductive polymer film such as polypyrrole as a solid electrolyte.

Conventional technology In conventional aluminum solid electrolytic capacitors that use a conductive polymer film such as polypyrrole as a solid electrolyte, an anodized film is formed on a roughened Full Minilam foil, which is then cut to a predetermined width and then cut into an aluminum tab. After forming a chemically oxidized and polymerized conductive polymer film of pyrrole, thiophene, aniline, or furan using an oxidizing agent on the anodic oxide film mentioned above, A solid electrolytic capacitor is constructed by forming an electropolymerized conductive polymer film by electrolytic polymerization on a capacitor element wound together with a separator such as electrolytic paper or plastic nonwoven fabric cut to a width wider than the width of the cut anode foil. was.

Problems to be Solved by the Invention In the solid electrolytic capacitor described above, during chemical oxidative polymerization, the oxidizing agent and monomer solution do not penetrate to the electrode surface of the wound anode body. After the molecules are formed, they are wound to form a capacitor element, and then a solid electrolyte layer is formed by electrolytic polymerization, forming a Fluminium solid electrolytic capacitor. The conductive polymer film formed by chemical polymerization causes problems such as peeling and falling off, and has not been put into practical use.

Means for Solving the Problems The present invention solves the above-mentioned problems by forming an oxide film on a metal foil whose main component is aluminum, which has been roughened in advance, and then cutting it into a predetermined width to form an oxide film on the anode foil. The aluminum tab is connected and re-coated by winding it together with a separator having a width narrower than the anode foil, and pyrrole, pyrrole, and
This is an aluminum solid electrolytic capacitor characterized by forming a chemically oxidized and polymerized conductive polymer film and an electrolytically polymerized conductive polymer film of thiophene, aniline, or furan.

Function In the present invention, since the capacitor element is formed by winding together with a separator having a width narrower than the cut width of the anode foil used for the electrode, the oxidizing agent and monomer solution during chemical oxidation polymerization, as well as the polymer solution during electrolytic polymerization, The solid electrolyte can be formed after the capacitor element has been formed, and the yield of aluminum solid electrolytic capacitors can be significantly improved and leakage current can be reduced.

Example-1 An aluminum foil on which a dielectric film with a withstand voltage of 25 V was formed was used as an anode foil (width 3-× length 10 m), an aluminum tab was connected, and the anode foil was connected to Manila paper with a width of 1.5 mm. After winding them in layers and immersing them in a 7 settonitrile solution containing 3 mol/i of pyrrole monomer, they were immersed in an aqueous solution of 0.5 mol/i of ammonium persulfate as an oxidizing agent for 10 minutes, resulting in chemical oxidation polymerization with high conductivity. A molecular film was formed. Further, the anode foil was placed in a 7cetonitrile solution containing 0.02 mol/II of pyrrole monomer and 0.05 mol/i of tetrabutyl 7 ammonium toluenesulfonate as a supporting electrolyte, using a stainless steel plate as a cathode (negative electrode). , 5mA, 15
Electrolytic polymerization was performed for 0 minutes, and an electrolytically polymerized conductive polymer film made of electrolytically polymerized polypyrrole was laminated on the chemically polymerized conductive polymer film. Furthermore, a carbon layer was formed on this surface, a counter cathode lead was attached using silver paste, and the capacitor was packaged with epoxy resin.

The characteristics of this capacitor are shown in Table 1 as Example-1.

Example-2 An aluminum foil on which a dielectric film with a withstand voltage of 25 V was formed was used as an anode foil (width 31 + 11 + 1 x length 1 Onv++), an aluminum tab was connected, and the distance between the anode foil and the anode foil was 1.5 m.
N+ polypropylene non-woven fabric is layered and wound, and this is immersed in an aqueous solution of 0.05 mol/i of ammonium persulfate as an oxidizing agent, and then immersed in a 7 setonitrile solution containing 3 mol/l of pyrrole monomer for 10 minutes. A conductive polymer film was formed by chemical oxidation polymerization. Further, the anode foil was mixed with 0.02 mol/# of pyrrole monomer and 0.05 mol/# as a supporting electrolyte.
A stainless steel plate was used as a cathode (negative electrode) in a setonitrile solution containing 7 l of tetrabutylammonium toluenesulfonate.
Electrolytic polymerization was carried out at 0.5 mA for 150 minutes.
An electrolytically polymerized conductive polymer film made of electrolytically polymerized polypyrrole was laminated on a chemically polymerized conductive polymer film. moreover,
A carbon layer was formed on this surface, a counter cathode lead was attached using silver paste, and the capacitor was packaged with epoxy resin. The first characteristic of this capacitor is
This is shown as Example-2 in the table.

Comparative Example-1 Aluminum foil on which a dielectric film with a withstand voltage of 25 V was formed was used as an anode foil (3 strips x 1 nm in length), an aluminum tab was connected, and the anode and 1113.2 mm of manila paper were overlapped. Wrap it around and add 0.05 ammonium persulfate to it.
After being immersed in an aqueous solution of 3 mol/l of pyrrole monomer, it was immersed for 10 minutes in a 7 setonitrile solution containing 3 mol/l of pyrrole monomer to form a chemically oxidized and polymerized conductive polymer film. Example-1 below
A capacitor was manufactured by laminating and forming electropolymerized conductive polymer membranes in the same manner through the same process. The characteristics of this capacitor are shown in Table 1 as Comparative Example-1.

Comparative Example-2 An aluminum foil on which a dielectric film with a withstand voltage of 25 V was formed was used as an anode foil (width 3 IT II 11 x length 101 W+).
Connect the aluminum tabs and add 7 ammonium persulfate 0.0
After being immersed in a 5 mol/i aqueous solution, it was immersed for 10 minutes in a 7 setonitrile solution containing 3 mol/i of pyrrole monomer to form a chemically oxidized and polymerized conductive polymer film.

Then, the cap was wrapped with 3.2 nwm manila paper. Thereafter, through the same steps as in Example 1, an electrolytically polymerized conductive polymer film was similarly formed to produce a capacitor.

The characteristics of this capacitor are shown in Table 1 as Comparative Example-2.

In Examples 1 and 2, the width of the separator was narrower than the width of the full minilam foil, so the separator was wound so that the width of the full miniram foil protruding from both ends of the separator was approximately equal on both sides.

It should be noted that the non-defective product rate in Table 1 was determined by considering short-circuited products as defective, and the electrical characteristics show values obtained by measuring 100 non-defective products.

As shown in Table 1, the examples according to the present invention had good results in terms of the yield rate and each characteristic. In particular, it shows a remarkable improvement effect on the non-defective product rate and leakage current. The present invention is not limited to this example, and similar effects were obtained using other conductive polymers.

Furthermore, the effects of the present invention were confirmed under all conditions of chemical oxidative polymerization and electrolytic polymerization. If the width of the separator is wider than the width of the anode foil of the Full Minilam foil, each solution in chemical oxidation polymerization and the electrolytic polymerization solution will not penetrate sufficiently, resulting in an increase in leakage current or a decrease in the yield rate. It is better if the separator is narrower than the width of the anode, and preferably a separator made of electrolytic paper or plastic non-woven fabric cut to a width of 273 or less with respect to the width of the anode is suitable.

Effects of the Invention As described above, the Full Miniram solid electrolytic capacitor of the present invention greatly contributes to improving manufacturing yield, reducing leakage current, and improving reliability, and is of great industrial and practical value.

Claims (1)

[Claims] An oxide film is formed on a pre-roughened metal foil whose main component is aluminum, an aluminum tab is connected to the anode foil cut to a predetermined width, and the anode foil is wound together with a separator having a width narrower than the anode foil for reconversion. An aluminum solid electrolytic capacitor characterized in that a chemically oxidatively polymerized conductive polymer film and an electrolytically polymerized conductive polymer film of pyrrole, thiophene, aniline, or furan are formed on the oxide film.