JPH0260208B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for manufacturing a solid electrolytic capacitor, and particularly to a method for reducing leakage current characteristics caused by deformation of metal wires planted in a capacitor element. The present invention relates to a manufacturing method suitable for mass producing solid electrolytic capacitors.

[Prior Art] To explain a conventional solid electrolytic capacitor, as shown in Fig. 11, metal powder having a valve action such as tantalum, aluminum, niobium, etc. is press-molded into a cylindrical shape, and then sintered. A metal wire of the same type is planted in advance as an anode lead wire 2 on an anode body 1 made of
After welding, the anode body 1 is immersed in an electrolytic solution and electrochemically anodized to form an oxide film layer 4 as a dielectric layer on the surface of the anode body 1. Next, this oxide film layer 4 is When a semiconductor layer 5 such as a manganese dioxide layer or a lead dioxide layer is formed on top, and a cathode layer 6 consisting of a graphite layer (conductive carbon layer), a silver paste layer, etc. is formed, a capacitor, which is the main part of a solid electrolytic capacitor, is formed. An element is formed.
By the way, since the anode lead wire 2 is a metal wire made of the same material as the anode body 1 as described above, it cannot be used as an external lead wire that can be soldered as it is, so it was cut as shown in FIG. An L-shaped tin-plated copper-clad steel wire that can be soldered is welded to the anode lead wire 2 as an external lead wire 7 on the anode side.
However, according to such a welding process, a large mechanical impact force is applied to the anode lead wire 2, so that cracks may occur at the connection boundary between the anode body 1 and the anode lead wire 2, and in some cases, cracks may occur. Eventually, the anode lead wire 2 may come off from the anode body 1. If such an accident occurs after the formation of the oxide film layer 4 as described above, the oxide film layer 4 formed at the connection boundary between the anode body 1 and the anode lead wire 2 will be destroyed, or the semiconductor The leakage current characteristics deteriorated due to direct contact between the layers 5, and in some cases, the anode and cathode were short-circuited, making it impossible to function as a solid electrolytic capacitor.

Therefore, in order to reduce the mechanical impact force caused by welding the anode lead wire 2 and the external lead wire 7, the anode lead wire 2 is welded as shown in FIG.
An insulating resin layer 8 for reinforcement is formed on the base of the anode body 1 leading out from the anode body 1 .

[Problems to be Solved by the Invention] As a method for forming the insulating resin layer 8, for example, a coating method or a dripping method has been adopted, but these methods have poor workability and are preferred for mass production of solid electrolytic capacitors. The problem is that it is not.

[Means for Solving the Problems] However, the present invention provides a method for forming the insulating resin layer 8 that is suitable for mass-producing solid electrolytic capacitors. Specifically, a resin adhesion prevention layer is formed on the surface of the cathode layer 6 of the anode body 1 in the state shown in FIG. 11 by a dipping method, and then a reinforcing insulating resin layer 8 is formed by a dipping method. This is what I did.

[Example] Hereinafter, a method for manufacturing a solid electrolytic capacitor according to the present invention will be explained based on FIGS. 1 to 10.

First, as shown in FIG. 1, apply resin adhesion prevention liquid 9A.
The continuous anode body 1 in the state shown in FIG. 11 is immersed in the solution at once. Note that on the anode body 1, an oxide film layer 4, a semiconductor layer 5, and a cathode layer 6 are formed as in the conventional method.
is formed. In this dipping step, preferably the anode lead wire 2 is dipped in the resin adhesion prevention liquid 9A so that it does not adhere to it. After immersion, leave it indoors for about 5 minutes to form a resin adhesion prevention layer 9 on the circumferential surface and lower surface of the anode body 1 (the surface opposite to the surface from which the anode lead wire 2 is drawn out) as shown in FIG. . Examples of the resin adhesion prevention liquid 9A include "Surflon" (trade name) manufactured by Asahi Glass Co., Ltd. and "Daifree" (trade name) manufactured by Daikin Industries, Ltd.

Subsequently, as shown in FIG. 3, the continuous anode body 1 is immersed in an insulating resin liquid 8A made of epoxy resin or the like, and when pulled out of the same resin liquid 8A, the anode body 1 is formed as shown in FIG. An insulating resin liquid 8 is formed on the entire outer surface of 1. However, in this state, an external lead wire on the cathode side, which will be described later, cannot be fixed to the anode body 1. Therefore, when the lower surface of the anode body 1 is brought into contact with a sponge material 10 or the like as shown in FIG. 5, the uncured insulating resin layer 8 formed on the lower surface of the anode body 1 is will be removed. Immediately after removing the insulating resin layer 8, when the anode body 1 is turned upside down, since the resin adhesion prevention layer 9 has already been formed on the circumferential surface of the anode body 1, it will not adhere to the circumferential surface of the anode body 1. As shown in FIG. 7, the insulating resin layer 8, which had been in contact with the anode body 1, is moved to the base of the anode lead wire 2 from the anode body 1. In this state, the temperature is approximately
The insulating resin layer 8 is cured in an atmosphere of 150°C.

After forming the insulating resin layer 8 described above, the resin adhesion prevention layer 9 is removed using a fluorocarbon-based solvent or the like.
Note that if the resin adhesion prevention layer 9 is lost or damaged during curing of the insulating resin layer 8, there is no need to remove the resin adhesion prevention layer 9 using a solvent.

Next, as shown in FIG. 8, if necessary, a new cathode layer 66 is formed on the cathode layer 6, the anode lead wire 2 is cut, and an L-shaped anode side lead wire 7 is attached to the lead wire 2. are welded in the same manner as in the conventional method, and then a cathode layer 6 is deposited.
A lead wire 11 on the cathode side is soldered onto the capacitor 6 using a solder layer 12 and covered with an exterior resin body 13 to obtain a dip-shaped solid electrolytic capacitor A1.

Further, as shown in FIG. 9, a substantially U-shaped anode side terminal L1 is welded to the anode lead wire 2, and the cathode layer 66
A terminal plate L2 on the cathode side is soldered 12 thereon and covered with an exterior resin body 13 to obtain a prismatic chip solid electrolytic capacitor A2.

Furthermore, as shown in FIG. 10, the cap C1 on the disk on the anode side is welded to the anode lead wire 2, and the anode body 1 is fixed inside the arm-shaped cap C2 on the cathode side via the adhesive silver layer 14. , by covering with the intermediate resin body 15 and the outer resin body 13, a cylindrical chip-shaped solid electrolytic capacitor A3 is obtained.

[Effect] As described above, in the present invention, prior to forming the insulating resin layer 8, the resin adhesion prevention layer 9 is formed, and then the insulating resin layer 8 is attached by a dipping method to form the insulating resin layer 8. Since part of the resin layer 8 is removed and the insulating resin layer 8 is cured and formed in an inverted state, it is very convenient for mass production of solid electrolytic capacitors.

[Brief explanation of the drawing]

1 to 10 are diagrams for explaining the manufacturing method according to the present invention, in which FIG. 1 shows a state in which the anode body is immersed in a resin adhesion prevention solution, and FIG. 3 is a cross-sectional view showing the anode body on which a prevention layer is formed; FIG. 3 is a view showing the anode body immersed in an insulating resin liquid; FIG. 4 is a cross-sectional view showing the anode body on which an insulating resin layer is formed; FIG. 5 is a diagram showing a method for removing a part of the insulating resin layer formed on the anode body, FIG. 6 is a cross-sectional view showing the anode body with part of the insulating resin layer removed, and FIG. Figure 7 is a diagram showing the anode body shown in Figure 6 in an inverted state, Figures 8 to 10
Figures 11 and 11 are cross-sectional views showing solid electrolytic capacitors manufactured by the manufacturing method according to the present invention, respectively.
Figures 1 to 13 are diagrams for explaining the conventional manufacturing method, in which Figure 11 is a cross-sectional view of the anode body with the required layers formed, and Figure 12 shows the state in which the external leader wire on the anode side is fixed. The sectional view shown in FIG. 13 is a sectional view of an anode body on which a reinforcing insulating resin layer is formed prior to fixing the external lead wire on the anode side. In the figure, 1... anode body, 2... anode leader wire, 3...
... Metal plate, 4 ... Oxide film layer, 5 ... Semiconductor layer,
6, 66... Cathode layer, 7, 11... External leader line,
8...Insulating resin layer, 9...Resin adhesion prevention layer, 1
0...Sponge material, 12...Solder layer, 13...Exterior resin layer, 14...Adhesive silver layer, 15...Intermediate resin layer, L1, L2...Terminal board, C1, C2...Cap.

Claims (1)

[Claims] 1 A solid in which an oxide film layer, a semiconductor layer, and a cathode layer are sequentially formed on the surface of an anode body on which an anode lead wire is planted, and an insulating resin layer is further formed on the base of the anode lead wire from the anode body. In an electrolytic capacitor, prior to forming an insulating resin layer, a resin adhesion prevention layer is formed by a dipping method on the peripheral surface of the anode body and the lower surface on the opposite side from the surface from which the anode lead wire is led out,
Subsequently, an insulating resin layer is formed by a dipping method, the insulating resin layer adhering to the bottom surface of the anode body is removed, and the anode body is turned upside down to harden the insulating resin layer. A method for manufacturing a solid electrolytic capacitor.