JP2003142339A - Solid electrolytic capacitor structure and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a solid electrolytic capacitor which is to be reduced in size and in fraction defective, when the electrolytic capacitor has such a structure where a capacitor element 1 is located between an anode lead terminal 8 and a cathode lead terminal 9, an anode wire 3 protruding from an anode 2 of the capacitor element 1 is welded and fixed to the anode lead terminal, and a cathode film 6, located on the surface of the anode, is connected to the cathode lead terminal. SOLUTION: A groove 3a extending in a spiral, is provided on the anode wire 3 of a capacitor element 1, a recess 3b which cuts off the spiral groove 3 is provided in a region, in between the anode lead terminal 8 of the anode wire 3 and the anode 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a solid electric capacitor using a capacitor element made of a valve metal such as tantalum or niobium, and a manufacturing method thereof.

[0002]

2. Description of the Related Art A capacitor element used in this type of solid electrolytic capacitor is manufactured as shown in FIGS.

That is, first, as shown in FIG. 1, a valve action metal powder such as tantalum is used as a porous tip type anode body 2.
Then, after the anode wire 3 is molded into a porous body so that the anode wire 3 protrudes from the one end surface 2a thereof, a high temperature (about 1500
℃) and sinter.

Next, as shown in FIG. 2, a plurality of the anode bodies 2 are attached to a metal horizontal bar A and the anode bodies 2 are connected to each other.
By fixing the anode wire 3 protruding from the welding by welding, the horizontal bars A are mounted at appropriate pitch intervals along the longitudinal direction.

Next, each anode body 2 in this horizontal bar A
3 is dipped in a chemical conversion solution C such as a phosphoric acid aqueous solution placed in a container B as shown in FIG. 3, and in this state, an anodic oxidation treatment of applying a direct current to the anode body 2 is performed. 4, a dielectric film 4 made of tantalum pentoxide or the like having a high insulating property is formed on the surface of each valve metal powder in the anode body 2, and the anode film 2 projects from one end surface 2a of the anode body 2. A dielectric film 4 ′ made of tantalum pentoxide having a high insulating property is also formed on the surface of the root of the wire 3.

Then, when the anodic oxidation treatment for forming the dielectric layers 4 and 4'is completed, each anode body 2 in the horizontal bar A is placed in a container D as shown in FIG. By dipping in the solid electrolyte aqueous solution E such as a manganese aqueous solution up to the one end face 2a of the anode body 2, pulling it up, and heating and baking the same several times (for example, about 10 times), it is possible to obtain FIG. As shown, the solid electrolyte layer 5 made of manganese dioxide is formed on the surface of the dielectric layer 4 in the anode body 2.

Then, each anode body 2 in the horizontal bar A is
As shown in FIG. 7, a cathode film 6 having a graphite film as an underlayer and a metal film such as silver as an upper layer is formed on a portion of the surface of the capacitor except for one end surface 2a thereof. obtain.

In this method of manufacturing a capacitor element,
In forming the solid electrolyte layer 5, as shown in FIG. 5, when the anode body 2 is dipped in a solid electrolyte aqueous solution E such as a manganese nitrate aqueous solution to the end surface 2a of the anode body 2, the solid The electrolyte aqueous solution E travels along the surface of the anode wire 3 and soaks up to a portion of the anode wire 3 beyond the dielectric film 4'at the root portion thereof where no dielectric film is formed. As a result, the solid electrolyte layer 5, which is the cathode side, comes into direct contact with the anode wire 3, which is the anode side, and electrical continuity occurs between the solid electrolyte layer 5 and the solid electrolyte layer 5, resulting in many defective products.

Therefore, conventionally, in order to prevent the above-mentioned solid electrolyte aqueous solution from bleeding up, a fluororesin or the like is attached to the base of the anode wire 3 protruding from each anode body 2 after the completion of the anodizing treatment. The synthetic resin ring body 7 is fitted and mounted, and with the ring body 7 mounted, the solid electrolyte layer 5 and the cathode membrane 6 are formed.

The capacitor element 1 manufactured in this manner has the anode wire 3 as shown in FIG.
By cutting a portion of the length L from the one end face 2a of the anode body 2 to separate it from the horizontal bar A, the capacitor element 1 is separated between the pair of left and right lead terminals 8 and 9 as shown in FIG. And the anode wire 3 of the capacitor element 1 is fixed to one anode lead terminal 8 by welding or the like, while the other cathode lead terminal 9 is electrically connected to the cathode film 6 of the anode body 2. By connecting and sealing all of them with a package body 10 made of synthetic resin, a package type solid electrolytic capacitor is assembled.

Further, when assembling the capacitor element 1 manufactured by using the horizontal bar A into a solid electrolytic capacitor, as shown in FIG. Is held by suction with the collet F, and in this state, the anode wire 3 in the capacitor element 1 is cut by the cutter mechanism G at a portion of the length L from the anode body 2 to be separated from the horizontal bar A, and then, This separated capacitor element 1
As shown in FIG. 10, the anode wire 3 of the capacitor element 1 contacts the upper surface of the anode lead terminal 8 between the lead terminals 8 and 9 of the lead frame H while being sucked and held by the collet F. Supply to
While keeping the capacitor element 1 adsorbed and held by the collet F, the anode wire 3 in the capacitor element 1 is connected to the anode lead terminal 8 with a pair of energizing electrodes J1, J2.
Spot welding is performed by sandwiching.

[0012]

[Problems to be Solved by the Invention] This capacitor element 1
When assembling into the solid electrolytic capacitor shown in FIG. 8 using, the tip of the anode lead terminal 7 and the one end face 2 of the anode body 2
The dimension between a and a must be increased by the amount that the ring body 7 is arranged between them, and therefore the thickness of the ring body 7 is added to the total length dimension W in the solid electrolytic capacitor. Therefore, there is a problem in that the solid electrolytic capacitor becomes large in size and weight.

Further, conventionally, while the anode body 3 of the capacitor element 1 is still adsorbed and held by the collet F, the anode wire 3 protruding from the anode body 2 is cut and the anode lead of the anode wire 3 is cut. By performing spot welding to the terminal 8, bending stress and impact acting on the anode wire 3 at the time of cutting and spot welding the anode wire 3 are directly applied to the anode body 3, and thus the porous body is porous. There is also a problem that the anode body 3 which is brittle and is a sintered body is frequently subject to dielectric breakdown, resulting in a high incidence of defective products.

The present invention has a technical object to solve these problems.

[0015]

In order to achieve this technical object, the structure of the present invention is "a capacitor element is protruded from an anode body in the capacitor element between the anode lead terminal and the cathode lead terminal. While welding and fixing the anode wire to the anode lead terminal, in the solid electrolytic capacitor arranged to connect the cathode film on the surface of the anode body to the cathode lead terminal, the anode wire in the capacitor element, A spiral groove extending spirally on the surface is provided, and further, a recessed portion that divides the spiral groove is provided in a portion of the anode wire between the anode lead terminal and the anode body. ” .

Further, the manufacturing method of the present invention includes: a step of compacting and molding valve-action metal powder into a porous chip-type anode body so that an anode wire protrudes from one end face thereof, and then sintering; Against the step of forming a capacitor film by forming a solid electrolyte layer and then a cathode film by dipping the dielectric film by anodizing treatment into a solid electrolyte aqueous solution,
In the method for manufacturing a solid electrolytic capacitor, which comprises a step of welding and fixing the capacitor element to the anode lead terminal and the cathode lead terminal by welding and fixing the anode wire to the anode lead terminal, and connecting the cathode film to the cathode lead terminal.
As the night pole wire, using an anode wire formed by providing a spiral groove spirally extending on the surface, in the portion between the anode lead terminal and the anode body of the anode wire,
Before the step of forming the solid electrolyte layer, there is provided a step of providing a concave portion for dividing the spiral groove on the surface of the anode wire. It is characterized by

[0017]

While the anode wire in the capacitor element is provided with the spiral groove extending spirally on the surface thereof, the anode wire is provided at a portion of the anode wire between the anode lead terminal and the anode body. Before forming the solid electrolyte layer, by providing a recess portion that divides the spiral groove, when forming a solid electrolyte layer for the anode body in the capacitor element, this anode body in the solid electrolyte aqueous solution in the anode body When dipping to the part of one end surface, the solid electrolyte aqueous solution stains along the spiral groove on the surface of the anode wire by capillary action, and the solid electrolyte aqueous solution that has soaked enters the concave portion that divides the spiral groove. It is possible to reliably prevent bleeding beyond the recessed portion.

Further, as described above, since the anode wire is provided with the recessed portion, the anode wire is easily bent at the location of the recessed portion provided therein, so that the anode body in the capacitor element is While being held by the collet, when cutting the anode wire, and when the anode wire is welded to the anode lead terminal, bending stress and impact acting on the anode wire affect the anode body, It can surely be reduced by the recess.

Therefore, according to the present invention, it is possible to omit the mounting of the synthetic resin ring body at the root portion of the anode wire as in the conventional case, and the tip of the anode lead terminal is made to correspond to the anode body of the capacitor element. Since it can be brought closer to the end face by the amount that the ring body is not arranged between them, unlike the conventional case, the total length of the solid electrolytic capacitor can be shortened, and its size and weight can be reduced. Since the volume of the anode body can be increased as much as the ring body is not used, the capacity of the capacitor can be increased, and moreover, it is possible to reduce the occurrence of dielectric breakdown in the anode body during the assembly process of the solid electrolytic capacitor. The occurrence rate can be greatly reduced.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings of FIGS.

First, as the anode wire 3, as shown in FIG. 11, an anode wire 3 formed by engraving a spiral groove 3a spirally extending on the surface is used, and a valve action metal powder such as tantalum is used as shown in FIG. As shown in FIG. 3, the porous tip type anode body 2 is porous and solidified so that the anode wire 3 projects from one end surface 2a thereof, and then the high temperature (about 15
Sinter by heating to (00 ° C).

The spiral groove 3a of the anode wire 3 is engraved by a flat die or circular die type thread rolling machine or a planetary type thread rolling machine used when forming by screw rolling with a bolt or the like. be able to.

Next, of the anode wire 3 protruding from the anode body 2, the root of the anode wire 2 with respect to the anode body 2 is shown in FIG.
As shown by the chain double-dashed line in FIG.
As shown in FIG. 13, the root portion is provided with a recessed portion 3b that divides the spiral groove 3a.

Then, in the following, the capacitor element 1 is manufactured in the same manner as the conventional method described above.

That is, as shown in FIG. 2, a plurality of anode bodies 2 provided with the above-described anode wire 3 having the spiral groove 3a are protruded from the anode body 2 with respect to the metal horizontal bar A. By fixing the wire 3 by welding,
The horizontal bars A are mounted along the longitudinal direction at appropriate pitch intervals.

Next, each anode body 2 in this horizontal bar A is
3 is dipped in a chemical conversion solution C such as a phosphoric acid aqueous solution placed in a container B as shown in FIG. 3, and in this state, an anodic oxidation treatment of applying a direct current to the anode body 2 is performed. 4, a dielectric film 4 made of tantalum pentoxide or the like having a high insulating property is formed on the surface of each valve metal powder in the anode body 2, and the anode film 2 projects from one end surface 2a of the anode body 2. A dielectric film 4 ′ made of tantalum pentoxide having a high insulating property is also formed on the surface of the root of the wire 3.

Next, when the anodic oxidation treatment for forming the dielectric layers 4 and 4'is completed, each of the anode bodies 2 in the horizontal bar A is placed in a container D as shown in FIG. By dipping in the solid electrolyte aqueous solution E such as a manganese aqueous solution up to the one end face 2a of the anode body 2, pulling it up, and heating and baking the same several times (for example, about 10 times), it is possible to obtain FIG. As shown, the solid electrolyte layer 5 made of manganese dioxide is formed on the surface of the dielectric layer 4 in the anode body 2.

In forming the solid electrolyte layer 5, when the anode body is dipped in the solid electrolyte aqueous solution E up to one end surface of the anode body 2, the solid electrolyte aqueous solution E is obtained.
Will soak up along the spiral groove 3a on the surface of the anode wire 3 due to a capillary phenomenon. The solid electrolyte aqueous solution that has soaked along the spiral groove enters the recess 3b that divides the spiral groove. Since the solid electrolyte aqueous solution is stored here, it is possible to reliably prevent the solid electrolyte aqueous solution from penetrating beyond the recess 3b.

As a result, it is possible to omit the mounting of the synthetic resin ring body at the base of the anode wire 3 as in the conventional case, and the tip of the anode lead terminal 8 is connected to one end surface of the anode body 2 in the capacitor element 1. Since it is possible to approach 2a by the amount not provided with the ring body as in the conventional case, the total length W of the solid electrolytic capacitor can be shortened.

Next, each anode body 2 in the horizontal bar A is
As shown in FIG. 7, a cathode film 6 having a graphite film as an underlayer and a metal film such as silver as an upper layer is formed on a portion of the surface of the capacitor except for one end surface 2a thereof. obtain.

As shown in FIG. 7, the capacitor element 1 manufactured in this manner cuts a portion of the anode wire 3 having a length L from the one end face 2a of the anode body 2 to form a horizontal bar. 14, the capacitor element 1 is arranged between a pair of left and right lead terminals 8 and 9 as shown in FIG. 14, and the anode wire 3 in the capacitor element 1 is connected to one anode lead terminal 8. While being fixed by welding or the like, the other cathode lead terminal 9 is electrically connected to the cathode film 6 of the anode body 2, and the whole of these is sealed by the package body 10 made of synthetic resin. Assembled into a solid electrolytic capacitor.

Also, when assembling this solid electrolytic capacitor, as in the conventional case, one capacitor element 1 in the horizontal bar A is replaced with a vacuum suction type collet F.
By suction, and in this state, the anode wire 3 in the capacitor element 1 is cut from the anode body 2 at a portion having a length L by a cutter mechanism G to be separated from the horizontal bar A, and then separated. Capacitor element 1
While being sucked and held by the collet F, as shown in FIG. 10, the anode wire 3 of the capacitor element 1 contacts the upper surface of the anode lead terminal 8 between the lead terminals 8 and 9 of the lead frame H. And further holding the capacitor element 1 on the collet F by suction, the anode wire 3 in the capacitor element 1 is supplied.
A pair of energizing electrodes J1,
Spot weld by sandwiching J2.

In assembling this solid electrolytic capacitor, since the recessed portion 3b is provided at the root portion of the anode wire 3 in the capacitor element 1, the anode wire 3 has the recessed portion 3b formed therein. When the anode wire 3 is cut while the anode body 2 of the capacitor element 1 is held by the collet F, and when the anode wire 3 is welded to the anode lead terminal 8, it is easily bent at a portion. It is possible to reliably reduce the bending stress and the impact acting on the anode wire 3 on the anode body 2 at the time of performing the above-mentioned recessed portion 3b.

The recessed portion 3b of the anode wire 3 may be formed after the solid electrolyte layer 5 is formed by anodizing treatment. Needless to say, the spiral groove 3a of the anode wire 3 is not limited to a single screw form, but may be a double or triple form multiple screw form.

[Brief description of drawings]

FIG. 1 is a perspective view showing an anode body in a capacitor element.

FIG. 2 is a perspective view showing a state in which a plurality of the anode bodies are mounted on a horizontal bar.

FIG. 3 is a cross-sectional view showing a state in which a dielectric film is formed on the anode body.

FIG. 4 is a vertical sectional front view of an anode body having a dielectric film formed thereon.

FIG. 5 is a cross-sectional view showing a state in which a solid electrolyte layer is formed on the anode body.

FIG. 6 is a vertical sectional front view of an anode body on which a solid electrolyte layer is formed.

FIG. 7 is a vertical sectional front view of a capacitor element in which a dielectric film, a solid electrolyte layer, and a cathode film are formed on an anode body.

FIG. 8 is a vertical sectional front view of a solid electrolytic capacitor using the capacitor element.

FIG. 9 is a diagram showing a state in which a capacitor element in the horizontal bar is separated from the horizontal bar.

FIG. 10 is a diagram showing a state in which a capacitor element separated from the horizontal bar is being supplied to a lead frame.

FIG. 11 is an enlarged view of the anode wire used in the embodiment of the present invention.

FIG. 12 is a vertical sectional front view of a capacitor element according to an embodiment of the present invention.

FIG. 13 is a vertical cross-sectional front view showing a state where a recess is provided in the anode wire.

FIG. 14 is a vertical sectional front view of the solid electrolytic capacitor according to the embodiment of the present invention.

[Explanation of symbols]

1 Capacitor element 2 Anode body 2a One end surface of anode body 3 anode wire 3a spiral groove 3b recess 4,4 'Dielectric film 5 Solid electrolyte layer 6 Cathode film 8 Anode lead terminal 9 Cathode lead terminal 10 package

Claims (2)

[Claims] 1. A capacitor element between an anode lead terminal and a cathode lead terminal, an anode wire protruding from an anode body of the capacitor element being welded and fixed to the anode lead terminal, and at the surface of the anode body. In a solid electrolytic capacitor arranged to connect a cathode film to the cathode lead terminal, an anode wire in the capacitor element is provided with a spiral groove extending spirally on the surface thereof, and further, among the anode wires, At the site between the anode lead terminal and the anode body,
A structure of a solid electrolytic capacitor, characterized in that a recessed portion that divides the spiral groove is provided. 2. A step of solidifying and molding a valve action metal powder into a porous chip-type anode body so that an anode wire protrudes from one end surface of the porous tip-type anode body, followed by sintering, and anodizing the anode body. A step of forming a solid electrolyte layer and then a cathode film into a capacitor element by dipping the dielectric film into an aqueous solution of the solid electrolyte, and using this capacitor element as an anode lead terminal and a cathode lead terminal, the anode wire of the anode wire. A method for producing a solid electrolytic capacitor comprising a step of welding and fixing to a terminal and supplying the cathode film so as to connect to a cathode lead terminal, the anode comprising a spiral groove extending spirally on the surface of the anode wire. Using a wire, in the portion between the anode lead terminal and the anode body of this anode wire,
A method of manufacturing a solid electrolytic capacitor, comprising the step of providing a recessed portion that divides a spiral groove on the surface of the anode wire before the step of forming the solid electrolyte layer.