JP2007019054A - Solid electrolytic capacitor with built-in fuse - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chip-like solid electrolytic capacitor with a built-in fuse in which a fuse is connected, with no degradation in voluminal efficiency of a capacitor element. <P>SOLUTION: A capacitor element in which a dielectric oxide film, a solid electrolyte layer, a negative electrode draw-out layer are sequentially formed, with a positive electrode lead provided therein, an electrode substrate which is to be an electrode of a capacitor, and an armoring resin, are provided. The electrode substrate comprises: an insulating layer provided with a plurality of through holes or notches; a positive electrode side conductive plate arranged at the through hole or notch; a negative electrode side conductive plate; a conductive plate for an auxiliary electron; and positive electrode side and negative electrode side external electrode layers. The positive electrode side conductive plate or negative electrode side conductive plate is connected to the conductive plate for auxiliary electrode by way of a fuse. The positive electrode side conductive plate is connected to the positive electrode side external electrode layer, and the negative electrode side conductive plate is connected to the negative electrode side external electrode layer. The positive electrode lead is connected to the positive electrode side conductive plate by way of a metal strip and conductive adhesive. A negative electrode drawn-out layer of the capacitor element is connected to the negative electrode side conductive plate by way of the conductive adhesive. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid electrolytic capacitor with a built-in fuse.

As shown in FIG. 5, the conventional chip-type solid electrolytic capacitor with a built-in fuse connects the lead frame 13 and the capacitor element 2 with a thermal fuse by wire bonding, ultrasonic connection or thermocompression bonding. (For example, see Patent Document 1)
Japanese Patent Publication No. 7-38367

  In the conventional technology, as described above, since the fuse is connected between the lead frame and the capacitor element, there is a problem that the volume efficiency of the internal element is reduced by the space for connecting the fuse, and the solid electrolytic capacitor is downsized. In addition, it was difficult to increase the capacity.

  The present invention solves the above problems, and provides a chip-type solid electrolytic capacitor with a small size and a large capacity, which does not cause a decrease in volumetric efficiency of internal elements due to connection of fuses.

That is, the present invention comprises a capacitor element comprising an anode lead, a dielectric oxide film, a solid electrolyte layer, and a cathode lead layer sequentially formed, an electrode substrate serving as a capacitor electrode, and an exterior resin.
The electrode substrate includes an insulating layer having a plurality of through holes or notches, an anode side conductive plate, a cathode side conductive plate and an auxiliary electrode conductive plate disposed in the through holes or notches, an anode side, and A cathode-side external electrode layer;
The anode side conductive plate and the auxiliary electrode conductive plate are connected via a fuse, the anode side conductive plate and the anode side external electrode layer, the cathode side conductive plate and the cathode side external electrode layer are respectively connected,
Further, the anode lead is connected to the auxiliary electrode conductive plate via the metal strip and the conductive adhesive, and the cathode lead layer of the capacitor element is connected to the cathode side conductive plate via the conductive adhesive. This is a solid electrolytic capacitor with a built-in fuse.

In addition, a capacitor element having an anode lead, a dielectric oxide film, a solid electrolyte layer, and a cathode lead layer formed in this order, an electrode substrate serving as a capacitor electrode, and an exterior resin,
The electrode substrate includes an insulating layer having a plurality of through holes or notches, an anode side conductive plate, a cathode side conductive plate and an auxiliary electrode conductive plate disposed in the through holes or notches, an anode side, and A cathode-side external electrode layer;
The cathode side conductive plate and the auxiliary electrode conductive plate are connected via a fuse, the anode side conductive plate and the anode side external electrode layer, and the cathode side conductive plate and the cathode side external electrode layer are respectively connected.
Furthermore, the anode lead is connected to the anode side conductive plate via the metal strip and the conductive adhesive, and the cathode lead layer of the capacitor element is connected to the auxiliary electrode conductive plate via the conductive adhesive. This is a solid electrolytic capacitor with a built-in fuse.

  The present invention provides an auxiliary electrode conductive plate in the vicinity of either the anode or cathode side conductive plate, and connects the anode or cathode side conductive plate and auxiliary electrode conductive plate via a fuse, thereby connecting the fuse. Since the stress on the capacitor element at the time is reduced and the volumetric efficiency due to the fuse can be prevented, the leakage current is reduced, and a small-sized and large-capacity built-in solid electrolytic capacitor can be obtained.

Embodiments of the present invention will be described below with reference to the drawings.
[Example 1] Fuse connection between anode side conductive plate and auxiliary electrode conductive plate (FIGS. 1 and 2)
FIG. 1 is a sectional view of a solid electrolytic capacitor with a built-in fuse showing Example 1 of the present invention, and FIG. 2 is a plan view of an electrode substrate.
First, tantalum powder of valve action metal powder in which an anode lead made of tantalum wire is implanted is pressed and then sintered, and the obtained sintered body is sequentially provided with a dielectric oxide film, a solid electrolyte layer, and a cathode lead layer. Then, the capacitor element 2 is manufactured.
Next, at least two through holes are provided in the insulating layer 4, and the anode side conductive plate 3a, the cathode side conductive plate 3b, and the auxiliary electrode conductive plate 3c for connecting the fuse are fitted into the through holes, and the capacitor element An electrode substrate 7 is manufactured by forming plating layers 6a to 6d as a mounting portion and an external electrode layer forming portion.

Subsequently, the anode side conductive plate 3a and the auxiliary electrode conductive plate 3c are connected by a fuse 11 having a width of 15 μm, and the silicone resin 12 is covered on the fuse.
Next, the anode lead 1 and the plate-shaped metal strip 5 are resistance-welded, and the metal strip 5, the plating layer 6a on the auxiliary electrode conductive plate 3c, the cathode lead layer of the capacitor element 2, and the plating layer 6c are joined together. After each connection via the conductive adhesive 8, the resin is packaged.
Further, the external electrode layer 10 was formed on the surfaces of the anode-side external electrode plating layer 6b and the cathode-side external electrode plating layer 6d to produce a solid electrolytic capacitor with a built-in fuse.

[Embodiment 2] Fuse connection between cathode side conductive plate and auxiliary electrode conductive plate (FIGS. 3 and 4)
3 is a cross-sectional view of a solid electrolytic capacitor with a built-in fuse showing Example 2 of the present invention, and FIG. 4 is a plan view of an electrode substrate.
A solid electrolytic capacitor with a built-in fuse was produced in the same manner as in Example 1 except that the cathode side conductive plate 3b and the auxiliary electrode conductive plate 3c were connected by a fuse 11.

(Conventional example) Fuse connection between lead frame and capacitor element (Fig. 5)
FIG. 5 is a sectional view of a conventional solid electrolytic capacitor with a built-in fuse. In the same manner as in the example, a capacitor element 2 having an anode lead and having a dielectric oxide film, a solid electrolyte layer, and a cathode lead layer formed in order was prepared. Next, the anode lead 1 and the anode side lead frame 13 were formed. The capacitor element 2 and the cathode side lead frame 14 were connected with the conductive adhesive 8 after being connected with a fuse, and then covered with resin to produce a solid electrolytic capacitor with a built-in fuse.

  Table 1 shows the result of comparing the occupation ratio of the capacitor element volume and the leakage current with respect to the product volume of Examples 1 and 2 and the conventional example.

As is clear from Table 1, Examples 1 and 2 have a higher element occupancy rate than the conventional example, the volume efficiency of the internal elements is greatly improved, and the leakage current is also improved. .
The fuse is preferably made of lead, an alloy such as lead, tin, bismuth, or cadmium, aluminum, or copper from the viewpoint of cost and technology.

It is sectional drawing of the solid electrolytic capacitor with a built-in fuse by Example 1 of this invention. It is a top view of the electrode substrate of the solid electrolytic capacitor with a built-in fuse according to Example 1 of the present invention. It is sectional drawing of the solid electrolytic capacitor with a built-in fuse by Example 2 of this invention. It is a top view of the electrode board | substrate of the solid electrolytic capacitor with a built-in fuse by Example 2 of this invention. It is sectional drawing of the solid electrolytic capacitor with a built-in fuse by a prior art example.

Explanation of symbols

1 Anode lead 2 Capacitor element 3a Conductive plate (anode side)
3b Conductive plate (cathode side)
3c Conductive plate (for auxiliary electrode)
4 Insulating layer 5 Metal strip 6a Plating layer (Anode-side internal electrode)
6b Plating layer (Anode-side external electrode)
6c Plating layer (cathode side internal electrode)
6d Plating layer (cathode side external electrode)
7 Electrode substrate 8 Conductive adhesive 9 Exterior resin 10 External electrode layer 11 Fuse 12 Silicone resin 13 Anode lead frame 14 Cathode lead frame

Claims (2)

A capacitor element having an anode lead, a dielectric oxide film, a solid electrolyte layer, and a cathode lead layer sequentially formed, an electrode substrate that serves as an electrode of the capacitor, and an exterior resin;
The electrode substrate includes an insulating layer having a plurality of through holes or notches, an anode side conductive plate, a cathode side conductive plate and an auxiliary electrode conductive plate disposed in the through holes or notches, an anode side, and A cathode-side external electrode layer;
The anode side conductive plate and the auxiliary electrode conductive plate are connected via a fuse, the anode side conductive plate and the anode side external electrode layer, the cathode side conductive plate and the cathode side external electrode layer are respectively connected,
Further, the anode lead is connected to the auxiliary electrode conductive plate via the metal strip and the conductive adhesive, and the cathode lead layer of the capacitor element is connected to the cathode side conductive plate via the conductive adhesive. A solid electrolytic capacitor with a built-in fuse. A capacitor element having an anode lead, a dielectric oxide film, a solid electrolyte layer, and a cathode lead layer sequentially formed, an electrode substrate that serves as an electrode of the capacitor, and an exterior resin;
The electrode substrate includes an insulating layer having a plurality of through holes or notches, an anode side conductive plate, a cathode side conductive plate and an auxiliary electrode conductive plate disposed in the through holes or notches, an anode side, and A cathode-side external electrode layer;
The cathode side conductive plate and the auxiliary electrode conductive plate are connected via a fuse, the anode side conductive plate and the anode side external electrode layer, and the cathode side conductive plate and the cathode side external electrode layer are respectively connected.
Furthermore, the anode lead is connected to the anode side conductive plate via the metal strip and the conductive adhesive, and the cathode lead layer of the capacitor element is connected to the auxiliary electrode conductive plate via the conductive adhesive. A solid electrolytic capacitor with a built-in fuse.

Images