JP2995109B2 - Method for manufacturing solid electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a solid electrolytic capacitor having improved power supply means for forming an electrolytic polymer film on a chemical polymer film formed on a dielectric oxide film formed on an anode body.

[0002]

2. Description of the Related Art In general, a solid electrolytic capacitor forms a dielectric oxide film on the surface of a film-forming metal such as aluminum or tantalum, and a solid electrolyte such as manganese dioxide or a TCNQ complex and a cathode layer are formed on the dielectric oxide film. It is formed by forming sequentially. Those using manganese dioxide as the solid electrolyte have the disadvantage that the dielectric oxide film is easily damaged during the manufacturing process, and those using the TCNQ complex have the disadvantage of poor thermal stability.

On the other hand, in recent years, capacitors having a polymer film of a complex five-membered ring compound such as polypyrrol, polythiophene, and polyfuran formed on a dielectric oxide film by electrolytic oxidation polymerization and using a solid electrolyte have been proposed and attracted attention. However, since the dielectric oxide film is an insulator, it was not possible to form an electrolytic polymerized film directly on the surface.

Therefore, in order to form a polymer film as a solid electrolyte on the dielectric oxide film, a chemical polymer film is formed on the dielectric oxide film in advance by means of chemical oxidation polymerization.
An electrolytic polymer film was formed on the chemical polymer film.

Conventionally, this type of electropolymerized film forming means is generally used as an anode body 11 made of, for example, aluminum metal having a roughened surface and a dielectric oxide film formed thereon as shown in FIG. An anode lead-out terminal 12 is attached, and a portion of the anode lead-out terminal 12 adjacent to the anode body 11 is coated with, for example, a silicon tube, and is contracted by heating to form an insulating layer 13.

Next, the anode body 11 and the insulating layer 13
Up to the middle of 2 mol / l of pyrrole / ethanol
Immersion in a 0.5 mol / l aqueous solution of ammonium persulfate for 5 minutes to perform chemical oxidative polymerization on the dielectric oxide film immersed in these solutions and a part of the insulating layer 13. A chemically polymerized film 14 is formed.

Next, a power supply electrode 15 such as a platinum wire is brought into contact with the chemically polymerized film 14, and
ol / liter and an acetonitrile solution containing 1 mol / liter of sodium paratoluenesulfonate as a supporting electrolyte, and subjected to galvanostatic oxidation polymerization (1 mA / cm).
⁽² , 30 minutes) to form an electrolytic polymer film 16 on the chemical polymer film 14, then peel off the power supply electrode 15, and then immerse it in a colloidal carbon solution to form a carbon layer (not shown). ), A conductive coating film (not shown) is further formed thereon, a cathode is drawn out from a part of the conductive film, and finally an exterior is applied.

According to the method for manufacturing a solid electrolytic capacitor using the conductive polymer film having the above structure as a solid electrolyte, when the power supply electrode 15 is brought into contact with and peeled off from the chemical polymer film 14, the dielectric polymer oxide film The coating is apt to be damaged, and there is a problem that the leakage current and tan δ increase due to the damage. Further, it is extremely difficult to make the contact state (position, area, strength of contact, etc.) of the power supply electrode 15 uniform among a plurality. Because of the difficulty and the different contact state, there were variations in various characteristics among the plurality, which had a serious problem in practical use.

Furthermore, since the setting of the power supply electrode 15 at the time of electrolytic oxidation polymerization is a contact with a minute portion, the power supply operation is troublesome and is not suitable as an industrial means.

[0010]

As described above, the power supply means at the time of electrolytic oxidation polymerization having the above-mentioned structure has a problem in workability, but also causes serious drawbacks such as leakage current failure and tan δ failure. At the same time, variations in characteristics among the plurality were remarkable, resulting in problems to be solved practically.

The present invention has been made in order to solve the above-mentioned drawbacks. By improving the power supply means at the time of electrolytic oxidation polymerization, it is possible to improve the workability and greatly contribute to the improvement of various characteristics. It is an object of the present invention to provide a method for manufacturing a solid electrolytic capacitor using a molecular film as a solid electrolyte.

[0012]

According to a method of manufacturing a solid electrolytic capacitor according to the present invention, an anode lead-out terminal is attached to an anode body made of a film-forming metal having a dielectric oxide film formed thereon. forming an insulating layer in a portion adjacent to the anode body, forming a chemical polymerization film in succession to a part of the entire surface and the anode lead terminal of the dielectric oxide film and on said insulating layer, said anode Apply current from the extraction terminal
Forming an electrolytic polymer film on the chemical polymer film corresponding to the surface of the anode body by using the chemical polymer film in contact with the anode lead-out terminal as a power supply means , and at least the anode of the insulating layer. And removing a portion near the lead-out portion of the lead-out terminal together with the chemically polymerized film formed on the insulating layer.

In addition, a conductive layer is formed in place of the chemically polymerized film formed on the insulating layer, and a current is applied from an anode lead-out terminal to the anode.
An electropolymerized film can also be formed on a chemically polymerized film by using a conductive layer in contact with a lead terminal as a power supply means .

[0014]

According to the method of manufacturing a solid electrolytic capacitor configured as described above, the entire insulating layer and a part of the anode lead-out terminal are provided.
Also forms a chemically polymerized film or conductive layer, so that a current flows from the anode extraction terminal during electrolytic oxidation polymerization
The chemical polymer film or the conductive layer itself in contact with the terminal can function as the power supply means , a uniform electrolytic polymer film can be formed efficiently, and the workability greatly contributes to the improvement of various characteristics from the beginning. Has a function that can be.

[0015]

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

That is, as shown in FIG. 2, after attaching the anode lead-out terminal 2 to a square plate-shaped anode body 1 made of, for example, high-purity aluminum foil, whose surface has been roughened to form a dielectric oxide film, A portion of the anode lead-out terminal 2 adjacent to the anode body 1 is coated with a silicon tube and shrunk by heating to form an insulating layer 3.

Next, as shown in FIG. 3, the distance from the anode body 1 to the portion where the insulating layer 3 is formed and a part of the anode lead-out terminal 2 is 2 m.
dipped in a pyrrole / ethanol solution of ol / liter for 5 minutes, dipped to perform chemical oxidative polymerization followed by 0.5 mol / liter aqueous solution of ammonium persulfate for 5 minutes, the positive
A chemical polymer film 4 as a conductive polymer film is formed on the polar body 1, the insulating layer 3, and a part of the anode lead-out terminal 2 .

Next, as shown in FIG.
1 mol / l of pyrrole monomer and 1 mol / mol of sodium paratoluenesulfonate as supporting electrolyte
L was immersed in an acetonitrile solution containing an anode lead
An electric current flows from the terminal, and a constant current electrolytic oxidation polymerization (1 mA) is applied between the electrode and an external electrode (not shown) by using a chemically polymerized film 4 formed on the insulating layer 3 in contact with the anode extraction terminal as a power supply means.
/ Cm ² , 1 hour) to form an electrolytic polymer film 5 as a conductive polymer film on the chemical polymer film 4 corresponding to the surface of the anode body 1, and thereafter, as shown in FIG. At least the portion of the insulating layer 3 near the lead-out portion of the anode lead-out terminal 2 is removed together with the chemically polymerized film 4 formed on the insulating layer 3.

Next, the surface of the electrolytic polymer film 5 is immersed in a colloidal carbon solution to form a carbon layer (not shown) on the electrolytic polymer film 5, and a conductive coating is formed on the carbon layer. A cathode layer (not shown) made of a film is formed, a cathode lead-out terminal (not shown) is taken out from a part of the cathode layer, and finally, an exterior (not shown) is applied.

According to the method of manufacturing a solid electrolytic capacitor having the above-described structure, it is not necessary to use a thin platinum wire or the like as a power supply electrode as in the related art, and the chemically polymerized film 4 formed on the insulating layer 3 is not required. directly makes it possible to function as a power supply means, eliminates the trouble such as contact work feeding electrode, than it is from which contributes greatly to improving workability, chemical polymerization film 3 due to contact, peeling of the platinum wire, further Eliminates the risk of damage to the dielectric oxide film and the like, thus contributing to the improvement of leakage current and tan δ characteristics.

Further, since the chemically polymerized film 4 formed on the insulating layer 3 functions as the power supply means as it is, the contact state (position, area, strength of contact, etc.) of the power supply means among the plurality is uniform. And has an excellent advantage that there is no variation in various properties among a plurality.

In the above embodiment, a chemical polymer film is formed also on the insulating layer continuously with the chemical polymer film formed on the anode body, and this chemical polymer film is used as a power supply means during electrolytic oxidation polymerization.
As shown in FIG. 5, a portion of the anode lead-out terminal 2 adjacent to the anode body 1 is covered with a silicone tube and heat-shrinked to form an insulating layer 3 as shown in FIG. Is formed only on the dielectric oxide film, is connected to the chemical polymerized film 4 on the insulating layer 3, and is cured by, for example, applying a carbon paste to form a conductive layer 6. The conductive layer 6 is used as a power supply unit . Even when the electrolytic polymer film 5 is formed on the chemical polymer film 4, the same effect as described in the above embodiment can be obtained.

In each of the above embodiments, means for coating and heating and shrinking the silicon tube has been described as an example of the formation of the insulating layer 3. However, instead of the silicon tube, a silicon resin is provided at a necessary portion. May be applied and cured by heating.

Next, comparison of characteristics between the present invention and the conventional example will be described based on experimental results.

The following table shows the results of comparison of characteristics between the present invention and a conventional example. (Invention A) A rating of 10 V-2.2 μF obtained by the means described in the above-described embodiment illustrated and illustrated in FIGS. 1 to 4 using an aluminum foil of 60 μm in thickness and 3 mm × 5 mm as an anode body. Solid electrolytic capacitors. (Invention B) As the power supply means , a rated voltage of 10 V-2.
2μF solid electrolytic capacitor. (Conventional Example) A 3 mm × 3 mm aluminum foil having a thickness of 60 μm was used as an anode body, and was described as a conventional technique by exemplifying FIG.
A solid electrolytic capacitor rated at 10 V-2.2 μF obtained by means .

The number of samples is 100 for each of the present invention and the conventional example. The numerical values in the table are average values, and the numerical values in parentheses vary.

[0027]

[Table 1]

As is clear from the above table, the capacitance, ta
Although nδ is not much different from the present invention and the conventional example, it can be seen that the present invention is significantly superior to the conventional example in both leakage current and short-circuit failure.

From these results, it is found that power supply in electrolytic oxidation polymerization
As a means, a conductive layer provided in connection with the anode lead-out terminal attached to the anode body and provided in connection with the chemical polymerization film is used, and is in a conductive state with the anode lead-out terminal after forming the electrolytic polymerized film. By adopting a configuration in which the chemically polymerized film or the conductive layer portion is removed, the leakage current and short-circuit failure characteristics are improved in comparison with the conventionally used method of performing electrolytic oxidation polymerization by contacting the electrode wire with the chemically polymerized film. It has been found that it greatly contributes and has an excellent effect in practical use.

[0030]

According to the present invention, a solid electrolytic capacitor using, as a solid electrolyte, a conductive polymer film composed of a chemically polymerized film and an electrolytic polymerized film having high practical value and capable of greatly improving leakage current characteristics and short-circuit failure characteristics. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an element structure of a solid electrolytic capacitor according to one embodiment of the present invention.

FIG. 2 is a perspective view showing an anode body in the course of manufacture for explaining a method of manufacturing a solid electrolytic capacitor according to one embodiment of the present invention.

FIG. 3 is a perspective view showing a state in which a chemically polymerized film is formed on an anode body during manufacture for describing a method of manufacturing a solid electrolytic capacitor according to one embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a device structure after an electropolymerized film is formed during manufacture for describing a method of manufacturing a solid electrolytic capacitor according to one embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a device structure after formation of an electropolymerized film in the course of manufacture, for explaining a method of manufacturing a solid electrolytic capacitor according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view showing an element configuration during manufacture for describing a method of manufacturing a solid electrolytic capacitor according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode body 2 Anode lead-out terminal 3 Insulating layer 4 Chemical polymerization film 5 Electrolytic polymerization film 6 Conductive layer

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-310530 (JP, A) JP-A-1-105523 (JP, A) JP-A-2-303017 (JP, A) JP-A-3-303 78222 (JP, A) JP-A-3-167816 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01G 9/00-9/28

Claims (2)

(57) [Claims] 1. A step of attaching an anode lead terminal to an anode body made of a film-forming metal having a dielectric oxide film formed thereon, and forming an insulating layer on a portion of the anode lead terminal adjacent to the anode body. entire 及 of the dielectric oxide film and on said insulating layer
Forming a chemically polymerized film continuously on a part of the anode lead-out terminal and passing a current from the anode lead-out terminal,
Forming an electrolytic polymerized film on the chemically polymerized film corresponding to the surface of the anode body by using the chemically polymerized film in contact with the output terminal as a power supply means ; and at least a portion near the lead-out portion of the anode extraction terminal of the insulating layer. And a step of removing the same together with the chemically polymerized film formed on the insulating layer. 2. A step of attaching an anode lead-out terminal to an anode body made of a film-forming metal having a dielectric oxide film formed thereon, and forming an insulating layer on a portion of the anode lead-out terminal adjacent to the anode body. wherein the step of forming a dielectric oxide film on the chemical polymerization film, and forming the conductive layer is continuous with the chemical polymerization film on a part of the upper insulating layer and the anode lead terminal, the
Apply current from the anode lead-out terminal and come into contact with the anode lead-out terminal
Forming an electrolytic polymerized film on the chemical polymerized film using the conductive layer as a power supply unit, and removing at least a portion of the insulating layer near the lead-out portion of the anode lead-out terminal together with the conductive layer formed on the insulating layer. And a method for sequentially manufacturing the solid electrolytic capacitor.