JP3060971B2 - Chip type solid electrolytic capacitor with built-in fuse - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As a prior art, Japanese Patent Laid-Open Publication No.
The chip type solid electrolytic capacitor with a built-in fuse disclosed in Japanese Patent Publication No. 2 will be described with reference to FIG. 3, (A) is a perspective view seen from above, (B) is a perspective view seen from below, (C) is a cross-sectional view in a plane direction including a cutting line AB in (A), (D) (A) is a cross-sectional view in the longitudinal direction including the cutting line CD, (E) is a cross-sectional view in the short direction including the cutting line EF.

In a conventional chip-type solid electrolytic capacitor with a built-in fuse, as shown in FIG. 3, a cathode layer is provided on a peripheral surface of a capacitor element 1 formed by pressurizing and forming an anode lead. The external lead terminal 11 is led out to the end surface of the exterior resin 15, and the second and third external lead terminals 12, 13 whose central portions are welded to the ends of the fuse wires 14 connected to the cathode layer by the conductive adhesive 9. Are drawn out to the end face opposite to the end face from which the first lead terminal 11 is drawn out, and are configured by being covered with a resin as a three-terminal shape.

[0004]

In the above prior art, a fuse wire is connected between the second and third external lead terminals extending to the same end face, and the center portion is connected to the cathode layer. As a result, the effective length of the fuse line is inevitably shortened, and the variation in the resistance value is increased. For this reason, there is a problem that the fusing condition of the fuse wire is different for each product.

[0005] In addition, such a fuse mounting structure has a problem that the mounting of the fuse wire becomes difficult from a technical point of view.

Further, since all the external lead terminals (second and third external lead terminals) connected to the cathode layer are connected via fuse lines, screening with a current larger than the fuse capacity cannot be performed. Therefore, there is a problem that sufficient quality control by screening a large current becomes impossible.

Further, since the fuse wire is directly connected to the cathode layer, it is difficult to use solder as the bonding means, and in practice, a conductive adhesive must be used. However, when a thin fuse wire is connected with a conductive adhesive, the connection becomes unstable, and the resistance value varies greatly from this point as well, and the fusing condition of the fuse wire differs from product to product.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a chip-type fixed electrolytic capacitor with a built-in fuse, which can perform a fuse blowing check and a screening with a large current, has a stable fuse blowing characteristic, and can be manufactured easily by a method. It is.

[0009]

A feature of the present invention is that a solid electrolytic capacitor element having an anode lead planted and pressed and formed with a cathode layer on the periphery thereof, and an outer package for sealing the solid electrolytic capacitor element are provided. A resin, a first external lead terminal connected to the anode lead and leading to a first end surface of the exterior resin, a second external lead terminal leading to the first end surface of the exterior resin, An external auxiliary lead terminal connected to the cathode layer and led out to a second end surface opposite to the first end surface; one end portion connected to the second external lead terminal and the other end portion connected to the outside; A fuse type chip solid electrolytic capacitor having a fuse line connected to an auxiliary lead terminal and sealed with the exterior resin. Here, the external auxiliary lead terminal is connected to the cathode layer by, for example, a conductive adhesive of silver paste, and the fuse wire is connected to the second external lead terminal and the external auxiliary lead terminal by solder, respectively. Can be. Also,
The exterior resin may have a rectangular shape, and an end face in a longitudinal direction thereof may be the first and second end faces. Further, the first external lead terminal, the second external lead terminal, and the external auxiliary lead terminal may be formed from the same lead frame and may be formed from a metal plate having the same thickness.

According to the above configuration, the length of the fuse wire connected to the second external lead terminal and the external auxiliary lead terminal with a low melting point metal such as solder can be sufficiently secured.
In addition, since the length of the fuse line can be controlled, stable fuse blowing characteristics can be obtained.

Further, since the fuse wire is connected to the second external lead terminal and the external auxiliary lead terminal with a metal such as solder, the fuse wire can be easily connected in a technical manner, and the reliability of the connection can be improved. . Since the external auxiliary lead terminal, which is much wider than the fuse wire, is connected to the cathode layer, the connection is not unstable even if a conductive adhesive is used as the connection means.

Further, since the first external lead terminal and the external auxiliary lead terminal are connected without using a fuse wire,
Screening can be performed with a current larger than the fuse capacity, and sufficient reliability can be evaluated.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a chip-type solid electrolytic capacitor with a built-in fuse according to an embodiment of the present invention, wherein (A) is a perspective view from above, (B) is a perspective view from below,
(C) is a sectional view in a plane direction including a cutting line AB in (A), and (D) is a longitudinal sectional view including a cutting line CD in (A).

FIG. 2 is a view showing a process of assembling the capacitor according to the embodiment of the present invention, in which the lead frame and the capacitor element are assembled and then the fuse wires are connected.

In FIG. 1, a solid electrolytic capacitor element 1
Has an anode lead 6 implanted and formed by pressure, and a cathode layer is provided around the anode lead. That is, this solid electrolytic capacitor element 1 is obtained by pressing a similar metal powder into a prismatic shape around a metal wire having a valve action and then performing vacuum sintering to further form an oxide layer, a semiconductor layer,
An electrode lead layer is formed via a graphite layer.

The exterior resin 2 for sealing the solid electrolytic capacitor element 1 has a rectangular shape, and a first external lead terminal 3 connected to the anode lead 6 is led out from a first end face in the longitudinal direction. A second external lead terminal 4 extends from the same first end face.

An external auxiliary lead terminal 5 made of a wide metal plate is provided with a solid electrolytic capacitor 1
A conductive adhesive 9 such as a silver paste on the cathode layer
And is derived from an end face in a longitudinal direction opposite to the first end face of the exterior resin 2.

Inside the exterior resin 2, one end of the fuse element 1 is connected to the upper surface of the tip of the second external lead terminal 4 using solder 8 such as cream solder, and the other end of the fuse element 1 is connected. Is connected to the upper surface of the tip of the external auxiliary lead terminal 5 using solder 8 such as cream solder.

FIG. 2 illustrates a method for manufacturing the chip-type solid electrolytic capacitor with a built-in fuse shown in FIG.

First, as shown in FIG. 2A, a lead frame 10 obtained by pressing a metal plate is prepared. In this lead frame 10, a first external lead terminal 3 and a second external lead terminal 4 are formed from one frame frame toward the center, and external auxiliary leads 5 are formed from the other frame frame toward the center. Have been.

Next, as shown in FIG. 2B, the solid electrolytic capacitor element 1 is placed at the center, and the anode lead 6 is welded to the first external lead terminal 3.

Next, as shown in FIG. 2C, the external auxiliary lead 5 is bent and connected to the cathode layer on the outer surface of the solid electrolytic capacitor element 1 with a conductive adhesive. Also, solder 8
Is used to connect the second external lead terminal 4 and the external auxiliary lead terminal 5 with the fuse element 1. At that time, the capacitor element may be covered with a resin or the like to protect the capacitor element 1.

Thereafter, resin molding is carried out with an exterior resin, the respective lead terminals 3, 4, 5 are cut from the frame of the lead frame, and the portions of the lead terminals 3, 4, 5 derived from the exterior resin are cut. Is subjected to terminal bending molding so as to conform to the external dimensions, and each terminal is formed outside the product as shown in FIG. 1 to obtain a chip-type solid electrolytic capacitor with a built-in fuse according to the embodiment of the present invention.

[0025]

The first effect is that the fusing of the fuse line occurs under almost constant conditions.

The reason is that the second lead terminal and the external auxiliary lead terminal are arranged at different positions of the capacitor element, so that the length of the connected fuse line can be assured to be long and constant. This is because the connection between the fuse line and the fuse line can be reliably performed by a low melting point metal such as solder.

The second effect is that the method of mounting the fuse wires is simple.

The reason is that, similarly to the first effect, a long fuse wire can be ensured, and the fuse wire can be directly connected to the second lead terminal and the external lead terminal using a low-melting metal such as solder. Because.

The third effect is that the screening can be performed with a large current, so that the reliability of the capacitor can be improved.

The reason is that the first lead terminal and the external auxiliary lead are connected without passing through the fuse wire.
This is because a current larger than the fuse capacity can flow.

[Brief description of the drawings]

1A and 1B are diagrams showing a chip-type solid electrolytic capacitor with a built-in fuse according to an embodiment of the present invention, wherein FIG. 1A is a perspective view as viewed from above, FIG. 1B is a perspective view as viewed from below, and FIG. FIG. 3D is a cross-sectional view in a plane direction including a cutting line AB in FIG.
FIG. 4 is a longitudinal sectional view including a cutting line CD of FIG.

FIG. 2 is a diagram illustrating a method of manufacturing a chip-type solid electrolytic capacitor with a built-in fuse according to an embodiment of the present invention in the order of steps.

3A and 3B are diagrams showing a conventional chip-type solid electrolytic capacitor with a built-in fuse, wherein FIG.
(B) is a perspective view as viewed from below, (C) is a cross-sectional view in a plane direction including a cutting line AB in (A), and (D) is a longitudinal direction including a cutting line CD in (A). Sectional view, (E) is section line E-
It is sectional drawing of the short direction containing F.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 solid electrolytic capacitor element 2 exterior resin 3 first external lead terminal 4 second external lead terminal 5 external auxiliary lead terminal 6 anode lead 7 fuse wire 8 solder 9 conductive adhesive 10 lead frame 11 conventional first external Lead terminal 12 Conventional second external lead terminal 13 Conventional third external lead terminal 14 Conventional fuse wire 15 Conventional exterior resin

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01G 9/12 H01G 9/004

Claims (5)

(57) [Claims] 1. A solid electrolytic capacitor element having an anode lead implanted and formed under pressure and a cathode layer provided around the anode lead, an exterior resin for sealing the solid electrolytic capacitor element, and connected to the anode lead. A first external lead terminal leading to a first end face of the exterior resin; a second external lead terminal leading to the first end face of the exterior resin; and a first external lead terminal connected to the cathode layer. An external auxiliary lead terminal extending to a second end surface opposite to the end surface; and an external resin connecting one end portion to the second external lead terminal and connecting the other end portion to the external auxiliary lead terminal. And a fuse line sealed with a fuse. 2. The external auxiliary lead terminal is connected to the cathode layer by a conductive adhesive.
2. The external lead terminal and the external auxiliary lead terminal are connected to each other by soldering.
The chip-type solid electrolytic capacitor with a built-in fuse according to the description. 3. The solid electrolytic capacitor with a built-in fuse according to claim 2, wherein the conductive adhesive is a silver paste. 4. The chip type solid body with a built-in fuse according to claim 1, wherein said exterior resin has a rectangular shape, and its longitudinal end faces are said first and second end faces. Electrolytic capacitor. 5. The fuse according to claim 1, wherein the first external lead terminal, the second external lead terminal, and the external auxiliary lead terminal are made of a metal plate having the same thickness. Built-in chip type solid electrolytic capacitor.