JPH0620885A - Chip-type solid-state electrolytic capacitor - Google Patents

Abstract

PURPOSE:To obtain a chip-type solid-state electrolytic capacitor where outer electrode terminals excellent in dimensional accuracy can be formed and which can be mounted and soldered with an automatic mounting device. CONSTITUTION:A capacitive element 11 is so covered with a sheathing resin 16 as to enable an anode lead-out wire 12 to be lead out of the element 11 on one side, and a recess 15 where the bent anode lead-out wire 12 is housed is provided to the anode lead-out wire side of the sheathing resin 16, and a conductive paint 19 electrically connected to the anode lead-out wire 12 is filled partly or fully in the recess 15 for the formation of an anode terminal 23 where the recess 15 and the anode lead-out wire 12 are mechanically held. A cathode terminal 24 is provided to the side of the capacitive element 11 opposed to the anode terminal 23, where the cathode terminal 24 and the anode terminal 23 are formed flat so as to be nearly equal to each other in surface area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip solid electrolytic capacitor.

[0002]

2. Description of the Related Art A conventional chip-shaped solid electrolytic capacitor has a structure as shown in FIGS. That is, a dielectric oxide film formed by anodic oxidation is formed on the surface of a porous anode body that is equipped with the anode lead-out wire 1 and is made of tantalum metal that is a valve metal, and an electrolyte layer such as manganese dioxide is formed on this surface. And then the carbon layer and the cathode layer 2 are sequentially laminated to form the capacitor element 3
And the capacitor element 3 is covered with the exterior resin 4 so that the anode lead wire 1 and the cathode layer 2 protrude at both ends, and then the surface of the anode lead wire 1 protruding from the exterior resin 4 An anode metal layer 6 and a cathode metal layer 7 are formed on the exposed portion 2a of the cathode layer 2 and the anode lead-out surface 5 of the exterior resin layer 4.
After that, the anode side solder metal layer 8 and the cathode side solder metal layer 9 were formed by immersing in a solder plating or a molten solder bath.

[0003]

However, in the chip-shaped solid electrolytic capacitor configured as described above, since the anode lead wire 1 projects outward from the end surface of the exterior resin 4, a concave shape provided on the carrier tape is used. When the chip-shaped solid electrolytic capacitor housed in the housing is taken out by an automatic mounting device and then mounted on, for example, a printed circuit board, the anode lead-out wire 1 is caught on the inner surface of the recessed housing to mount the chip-shaped solid electrolytic capacitor. There was a problem that it could not be taken out smoothly from the concave storage part. Also,
Since the left and right surface areas of the external electrode terminals composed of the anode-side solder metal layer 8 and the cathode-side solder metal layer 9 are different, for example, a chip standing defect occurs on the printed circuit board when mounting by a reflow method using cream solder. There was a problem.

The present invention solves the above-mentioned problems of the prior art, and is capable of forming external electrode terminals with high dimensional accuracy, and can be surely mounted and soldered by an automatic mounting device. An object of the present invention is to provide a solid electrolytic capacitor.

[0005]

In order to achieve the above object, a chip solid electrolytic capacitor of the present invention comprises a dielectric oxide film and an electrolyte layer on the surface of an anode body made of a valve metal having an anode lead wire. A capacitor element formed by forming a cathode layer, and an exterior resin covering the capacitor element so that the anode lead wire is drawn out to one side, and the anode lead wire is bent on the anode lead wire side of the exterior resin. A concave portion for accommodating the anode lead-out wire is provided, and a conductive paint electrically connected to the anode lead-out wire is embedded in a part or the whole of the recessed portion so that the recess and the anode lead-out wire are mechanically held. And a cathode terminal portion electrically connected to the cathode layer of the capacitor element on the side opposite to the anode terminal portion, and the anode terminal portion and the cathode terminal portion are substantially the same. So that the area is obtained by constituting the flat.

[0006]

According to the above construction, since the anode lead wire is bent and accommodated in the recess provided on the anode lead wire side of the exterior resin, the anode lead wire projects outward from the end face of the exterior resin. In addition, a conductive paint electrically connected to the anode lead wire is embedded in a part or all of the recess so that the recess and the anode lead wire are mechanically held. Since it is provided, the chip-shaped solid electrolytic capacitor of the present invention is resistant to mechanical external stress, and as a result, the chip-shaped solid electrolytic capacitor of the present invention is not disconnected even when mechanical external stress is applied by an automatic mounting apparatus. There will be no problem of running out of capacity. Also,
Since the anode and cathode terminals are made flat so that they have almost the same surface area, they are not affected by the left-right variations in the external electrode terminals, and as a result, the chip-type solid electrolytic by the automatic mounting device is eliminated. The capacitor can be mounted surely, and the chip standing defect that has occurred on the printed circuit board at the time of mounting by the reflow method using the creamy solder is significantly reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a chip solid electrolytic capacitor according to an embodiment of the present invention, and FIG. 2 is a perspective view of the chip solid electrolytic capacitor of FIG. In FIGS. 1 and 2, reference numeral 11 denotes a capacitor element. The capacitor element 11 has a porous anode body made of tantalum having an anode lead wire 12 and a dielectric oxide film formed on the surface thereof by a general anodic oxidation method. It is formed by further forming a cathode layer 13 composed of an electrolyte layer, a carbon layer and a silver coating layer on top of this.

Then, of the cathode layer 13 provided around the capacitor element 11, a cathode conductor layer 14 made of a conductive material is formed thickly on the surface facing the lead-out surface of the anode lead wire 12, and then the capacitor is formed. A concave portion 15 for folding and housing the anode lead wire 12 is provided on a surface of the element 11 from which the anode lead wire 12 is drawn out, and the capacitor element 11 is provided.
Also, the cathode conductor layer 14 and the anode lead wire 12 are covered with the exterior resin 16 so as to be drawn out to one side, and thereafter, the side opposite to the anode lead wire 12 of the exterior resin 16 is cut or ground to form the cathode conductive material. Exposed surface 14 of body layer 14
a is made flat.

Next, in order to mechanically and electrically connect the anode lead-out wire 12 folded and housed in the recess 15 and the anode lead-out surface 17 of the exterior resin 16, the interior of the recess 15 of the exterior resin 16 on the side of the anode lead-out 12 is formed. The exterior resin 1 in which a conductive paint 19 is embedded in a part or all of the above and the anode lead wire 12 is included.
Apply the conductive paint 19 also on the anode lead-out surface 17 of 6,
The coating is formed so that the recess 15 and the anode lead wire 12 are mechanically held. The conductive paint 19 used at this time is preferably one in which electroless plating metal is deposited on the conductive powder contained in the conductive paint. Next, the surface on which the metal layer is formed by the electroless plating method is mechanically roughened by a wet blast method or the like, and then a fluoride such as hydrofluoric acid, silicofluoric acid, borofluoric acid, or ammonium fluoride is included. Chemical etching is performed with the resulting solution. Next, palladium for electroless plating is applied, and thereafter, the anode underlayer 21 and the cathode underlayer 22 are formed by a nickel layer of about 1 to 5 μm by the electroless plating, and then the anode underlayer 21 is formed. An anode terminal portion 23 and a cathode terminal portion 24 were electrodeposited on the surface of the cathode underlayer 22 with an electroplating method using a solder layer having a thickness of about 2 to 8 μm to produce a chip solid electrolytic capacitor.

In the above-described embodiment of the present invention, the anode lead-out wire 12 is bent and accommodated in the recess 15 provided in the outer-wrapping resin 16.
6 does not project outward from the end face of the capacitor 6, and the cathode lead-out surface 18 of the exterior resin 16 is cut or ground to expose the cathode conductor layer 14 to form a flat structure. It is possible to obtain an outer shape with high dimensional accuracy without being affected by the dimensional variation of the. Further, since the conductive paint 19 electrically connected to the anode lead-out wire 12 is embedded in a part or the whole of the recess 15, the end face on the side of the anode lead-out wire 12 is flat as compared with the conventional product, and as a result, the anode The surface areas of the terminal portion 23 and the cathode terminal portion 24 as the left and right external electrode terminals are substantially the same.

From these things, even when the chip-shaped solid electrolytic capacitor of the present invention housed in the recessed housing portion provided in the carrier tape is taken out by the automatic mounting apparatus and mounted on the printed circuit board, the chip can be mounted as in the conventional case. The solid electrolytic capacitor does not get caught on the inner side surface inside the concave accommodating portion provided on the carrier tape. Further, when mounting by a reflow method using creamy solder, it has the following features as compared with the conventional one. First, the cream solder is printed on the printed circuit board using screen printing, etc., and the chip solid electrolytic capacitor is mounted on the printed cream solder, and the chip solid electrolytic capacitor is attached by the adhesive force of the cream solder. Are retained, and the cream solder melts when the printed circuit board is run through a reflow oven. In this case, since the surface areas of the left and right external electrode terminals in the chip-shaped solid electrolytic capacitor, that is, the anode terminal portion 23 and the cathode terminal portion 24 are substantially the same, the solder gets wet at the same time and the anode side solder and the cathode side solder Thus, they are simultaneously pulled by the molten solder.

At this time, if the surface areas of the left and right external electrode terminals are unbalanced, chip standing defects frequently occur. However, the chip-shaped solid electrolytic capacitor in one embodiment of the present invention uses the left and right external electrode terminals, that is, the anode terminal portion. Since the surface areas of the cathode 23 and the cathode terminal portion 24 are substantially the same, even when the solder is melted and pulled right and left evenly, the solder is held on the printed circuit board for reliable soldering.
As a result, even if the chip soldering is mounted on the printed circuit board by the reflow method using the creamy solder, the chip standing defect is significantly reduced, and as a result, the mounting at the time of soldering can be surely performed.

[0014]

As described above, in the chip solid electrolytic capacitor of the present invention, since the anode lead-out wire is bent and accommodated in the concave portion provided on the side of the anode lead-out wire of the exterior resin, the anode lead-out wire is It does not project outward from the end face of the exterior resin, and a conductive paint electrically connected to the anode lead wire is embedded in a part or all of the recess to make the recess and the anode lead wire mechanical. Since it is provided with an anode terminal portion adapted to be retained in the chip-shaped solid state of the present invention against mechanical stress from the outside, as a result, for example, against mechanical external stress due to an automatic mounting apparatus. The electrolytic capacitor does not have the problem that its connection is broken and the capacity becomes insufficient.

Further, since the anode terminal portion and the cathode terminal portion are flat so as to have substantially the same surface area, they are not affected by the left and right variations in the external electrode terminals, and as a result, the automatic mounting apparatus The chip-shaped solid electrolytic capacitor can be mounted reliably, and the chip standing failure that has occurred on the printed circuit board during mounting by the reflow method using cream-like solder is greatly reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a chip solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 2 is a perspective view of the chip solid electrolytic capacitor.

FIG. 3 is a cross-sectional view of a conventional chip solid electrolytic capacitor.

FIG. 4 is a perspective view of the chip solid electrolytic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Capacitor element 12 Anode lead wire 13 Cathode layer 15 Recessed portion 16 Exterior resin 19 Conductive paint 23 Anode terminal portion 24 Cathode terminal portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koji Ueoka 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A capacitor element comprising a dielectric oxide film, an electrolyte layer, and a cathode layer formed on the surface of an anode body made of a valve metal having an anode lead wire, and the capacitor element having the anode lead wire. Is provided on one side with an exterior resin covering the anode resin, and a concave portion for accommodating the anode lead wire is provided on the anode lead wire side of the exterior resin, and the anode lead wire is partly or wholly inside the recess. An anode terminal portion is provided in which a conductive paint electrically connected to is embedded so that the recess and the anode lead wire are mechanically held, and the anode terminal portion is opposite to the cathode layer of the capacitor element. A chip-shaped solid electrolytic capacitor in which a cathode terminal portion to be electrically connected is provided, and the anode terminal portion and the cathode terminal portion are flat so as to have substantially the same surface area.