JP2776126B2 - Chip solid electrolytic capacitor with fuse and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolytic capacitor, and more particularly, to a chip solid electrolytic capacitor with a fuse and a method of manufacturing the same.

[0002]

2. Description of the Related Art In general, solid electrolytic capacitors are used in various electronic circuits, and it is considered that a small failure rate is an advantage. However, once a failure occurs, a short circuit often occurs. If a large short-circuit current flows in such a case, the capacitor element may generate heat and burn out.

In order to prevent the capacitor element from being burned out at the time of failure due to the excessive short-circuit current and to protect the peripheral circuit components, it is necessary to release the capacitor from the short circuit. Conventionally, a solid electrolytic capacitor having a built-in fuse has been used for this purpose. Such a solid electrolytic capacitor is called a solid electrolytic capacitor with a fuse. FIG. 5 is a partial sectional perspective view showing the structure of a conventional chip solid electrolytic capacitor with a fuse. FIG. 6 is a sectional view of the conventional chip solid electrolytic capacitor with a fuse shown in FIG. 5 and a plan view of a cathode terminal before assembly. The capacitor element 1 includes an anode lead 2 and a cathode layer 3, and an anode terminal 4 is connected to the anode lead 2. The fuse 7 is connected to the internal connection 5 of the cathode terminal 5.
a and the external lead portion 5b, and is covered with a protective resin 11 for protecting the fuse 7. Cathode layer 3
Are bonded by solder 12 to the internal connection portion 5a of the cathode terminal 5 containing a fuse. These are insulated by an exterior resin 10.

[0004]

The above-mentioned conventional chip solid electrolytic capacitor with a fuse has the following drawbacks because the internal connection portion 5a of the cathode layer 3 and the cathode terminal 5 containing the fuse 7 are connected by soldering. . The cathode terminal 5 has a built-in fuse 7, and it is necessary to insulate the fuse portion with a protective resin 11 in order to prevent the disconnection of the fuse due to handling during the manufacturing process. For this reason, between the cathode layer 3 and the internal connection portion 5a Then, a step corresponding to the thickness of the protective resin 11 is generated, and when the solder is melted to connect the cathode layer 3 and the internal connection portion 5a, the connection is restored while the solder is uncured due to the elastic restoration of the internal connection portion 5a. There was a problem that the connection was cut off and the reliability of the cathode connection could not be ensured.

An object of the present invention is to prevent the internal connection of the cathode terminal from being disconnected due to elastic restoration while the solder is not cured when the cathode terminal and the capacitor element are connected by solder. Another object of the present invention is to provide a chip solid electrolytic capacitor with a fuse, which has a reduced defective rate and improved connection reliability.

[0006]

According to the present invention, there is provided a chip solid electrolytic capacitor element with a fuse, comprising: an anode terminal connected to an anode lead derived from the solid electrolytic capacitor element;
A cathode terminal with a fuse connected to the cathode layer of the solid electrolytic capacitor element, and an exterior resin covering the whole except for a predetermined portion of the anode terminal and the cathode terminal, wherein the cathode terminal has an internal connection portion and an external lead portion. In a solid electrolytic capacitor with a fuse made of a resin for protecting and covering a fuse connecting both of them, the internal connection portion of the cathode terminal has a rectangular element connection portion, a fuse connection portion located on a diagonal of the rectangle, and It is characterized by being constituted by the protruding portion, and the manufacturing method thereof,
The step of connecting the cathode terminal to the capacitor element includes, after forming a solder layer on the capacitor element, aligning the cathode terminal with a predetermined position on the capacitor element, and bringing the protrusion of the fuse connection portion of the cathode terminal into contact with the capacitor element. Hold down until
It is characterized by heating the fuse connection.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a perspective view, partly in section, showing the internal structure of one embodiment of the present invention. FIG. 2 is a plan view of the cathode terminal of the first embodiment shown in FIG. It is.

An anode body is formed by press molding with a part of the anode lead 2 buried in a metal powder having a valve action such as tantalum or aluminum, and the anode body is vacuum-sintered and then anodized. By a known means on the anodic oxide film,
A manganese dioxide layer, a carbon layer, a plating layer, and a solder layer are sequentially formed to obtain a solid electrolytic capacitor element 1. next,
After the fuse 7 is connected to the internal connection portion 5a of the cathode terminal 5 and the external lead terminal 5b by a welding method, the fuse 7 is covered with the protective resin 11 by, for example, molding.

Next, the anode lead 2 led out of the solid electrolytic capacitor element 1 is resistance-welded to the anode terminal, and the cathode layer 3 formed on the outer periphery of the solid electrolytic capacitor element 1 is cathode-heated with high-temperature solder 12. Connected to the internal connection part 5a of the terminal 5.

Next, these are insulated and sheathed with a sheath resin 10 to obtain a chip solid electrolytic capacitor with a fuse of the present invention.

Next, a method of manufacturing the cathode terminal 5 will be described.
A method for connecting the capacitor and the solid electrolytic capacitor element 1 will be described in detail.

FIG. 2 shows the shape of the cathode terminal 5 used in this embodiment before assembly. The internal connection portion 5a and the external lead-out terminal 5b are integrally formed, and the frame 14
Supported by In this embodiment, first, the fuse 7 is welded between the internal connection portion 5a and the external lead-out terminal 5b. Next, the internal connection part 5a and the external lead-out terminal 5b
Are covered with a protective resin 11 by a molding method with a predetermined portion exposed. At this time, a gap of about 0.1 mm is provided between the end face of the internal connection portion 5a and the protective resin 11. Thereafter, the exposed portions of the internal connection portion 5a, A-A ₁ line,
B-B ₁ line, C-C ₁ line and, by cutting with D-D ₁ line, obtaining a cathode terminal 5 having the fuse function.

[0013] Here, A-A ₁ line gets a protruding portion 5c is cut at the 0.5mm than the internal connecting end face. next,
A high-temperature solder cream for connection was applied to the surface of the capacitor element 1 and was once melt-hardened to form a solder layer 13. Next, after the internal connecting portion 5a is aligned with a predetermined position of the solid electrolytic capacitor element 1, the protruding portion 5c of the internal connecting portion 5a is pressed against the solid electrolytic capacitor element 1 by the pressing claw 13. While maintaining this state, the heating iron 15 is connected to the internal connection portion 5a.
To melt the high-temperature solder layer 13 solder. Next, after the high-temperature solder layer 12 is cured, the holding claws 13 are removed,
The connection between the solid electrolytic capacitor element 1 and the cathode terminal 5 was completed.

Next, a predetermined portion of the anode terminal 4 and the cathode terminal 5 is exposed on the assembled product, and is insulated with an exterior resin 10 by a transfer molding method.

Thereafter, the frame 14 is cut along the line EE ₁ shown in FIG. 2B, and the anode terminal 4 and the cathode terminal 5 are bent along the outer wall of the exterior resin 10 to form the first terminal of the present invention. The chip solid electrolytic capacitor with a fuse according to the example was completed.

FIG. 3 is a perspective view, partially in cross section, of another embodiment of the present invention, and FIG. 4A shows the shape of a cathode terminal. Provided. By using the shape of the cathode terminal of the present embodiment, as shown in FIG.
Since the pressing step can be performed in frame units, there is an advantage that the apparatus and the steps can be simplified. The material other than the frame shape and the manufacturing process are the same as in the first embodiment.

[0017]

As described above, according to the present invention, a projection is provided at the internal connection of the cathode terminal with a fuse, and the internal connection of the cathode terminal is securely connected to the solid electrolytic capacitor element by utilizing the projection in the connection step. , And the contact state can be easily maintained until the connection solder is melted and cured. As a result, about 0.5% of the defects that the connection between the cathode terminal once connected and the solid electrolytic capacitor element was lost due to the elastic recovery of the frame while the molten solder was uncured occurred. According to the present invention, similar defects can be eliminated, the defect rate can be reduced, the number of inspection steps for removing the defects can be reduced, and the connection reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional perspective view of a solid electrolytic capacitor with a fuse according to an embodiment of the present invention.

FIG. 2 is a plan view of a cathode terminal before assembly and a cross-sectional view of a cathode connection step of the first embodiment of the present invention shown in FIG. 1;

FIG. 3 is a partial sectional perspective view of a solid electrolytic capacitor with a fuse according to another embodiment of the present invention.

FIG. 4 is a plan view of a cathode terminal before assembly and a cross-sectional view of a cathode connection step of the second embodiment of the present invention shown in FIG. 3;

FIG. 5 is a partial sectional perspective view of a conventional solid electrolytic capacitor with a fuse.

6 is a sectional view of the solid electrolytic capacitor with a fuse shown in FIG. 5 and a plan view of a cathode terminal before assembly.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Anode lead 3 Cathode layer 4 Anode terminal 5a Internal connection part 5b External lead-out part 5c Projection part 7 Fuse 10 Outer resin 11 Protective resin 12 High-temperature solder 13 Holding claw 14 Frame 15 Heating iron

Claims (2)

(57) [Claims] 1. A solid electrolytic capacitor element, an anode terminal connected to an anode lead derived from the solid electrolytic capacitor element, a cathode terminal with a fuse connected to a cathode layer of the solid electrolytic capacitor element, and the anode A chip solid electrolytic capacitor with a fuse, comprising a terminal and an exterior resin covering the whole except for a predetermined portion of the cathode terminal, wherein the cathode terminal is made of a resin for protecting and covering an internal connection portion, an external lead portion, and a fuse connecting both of them. 2. The chip solid electrolytic capacitor with a fuse according to claim 1, wherein the internal connection portion of the cathode terminal comprises a rectangular element connection portion, a fuse connection portion and a protrusion located on a diagonal of the rectangle. 2. The method according to claim 1, wherein the internal connection part is a rectangular element connection part,
The step of connecting the cathode terminal formed by the fuse connection part and the protrusion located on the diagonal of the rectangle to the solid electrolytic capacitor element includes the steps of: forming a solder layer on the capacitor element; and connecting the cathode terminal on the capacitor element. Manufacturing a chip solid electrolytic capacitor with a fuse, comprising: a step of pressing a projection of an internal connection portion of a cathode terminal until it contacts a capacitor element after being adjusted to a predetermined position; and a step of heating the internal connection portion. Method.