JP2575351Y2 - Solid electrolytic capacitor with built-in fuse - 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 having a built-in fuse, and more particularly to a structure of a fuse element.

[0002]

2. Description of the Related Art In recent electronic devices, miniaturization, weight reduction, and high functionality are rapidly progressing. At the same time, with the growing social needs for safety, these electronic devices have become important in product functions. On the other hand, safety is an important development issue for electronic components as well as miniaturization and weight reduction. In particular, in the case of a polar capacitor having a solid electrolyte, large leakage current during reverse mounting or failure may result in burning of the capacitor element or burning out of peripheral components and printed wiring boards, resulting in burnout. Care must be taken. Against this background, various types of tantalum solid electrolytic capacitors with built-in fuses have been developed. At the same time, the needs for fuse blowing characteristics have been diversified.

FIG. 6 is a central sectional view of an example of a conventional tantalum solid electrolytic capacitor chip type with a built-in fuse, and the structure thereof will be described below. In this type of capacitor, a tantalum wire 2 embedded in a capacitor element 1 is connected to an anode terminal 3 by resistance welding or the like. The surface of the capacitor element 1 is generally covered with a cathode conductive layer such as solder. An insulating resin 21 is applied to a part of the surface of the capacitor element 1. Next, one end of the fuse element 7 is connected to a part of the surface conductive layer of the capacitor element 1 by solder A22. Another part of the fuse element 7 is connected to one end of the cathode terminal 4 by a solder B23.
Connected by At this time, the insulating resin 21 is provided so as to prevent the fuse element 7 from contacting the cathode conductive layer of the capacitor element 1. The fuse element 7 is made of a solder alloy and has a thread shape with a diameter of about 0.1 mm.
The capacitor element 1 connected as described above is protected by the exterior insulating case 5 made of epoxy resin or the like.

[0004]

In this conventional solid electrolytic capacitor with a built-in fuse, a thread-shaped fuse element is used as a fuse element, and therefore has the following disadvantages. (1) Since the wire diameter is thin and soft, the strength is low and the connection efficiency of the fuse element is poor. (2) The fuse element may be damaged. (3) It is difficult to incorporate a fuse with low current fusing characteristics. This is because it is necessary to lower the melting point and thinner the material in order to achieve low fusing characteristics, but if this is done, the problems of the above items (1) and (2) become more pronounced. . For this reason, there is a problem that it is difficult to obtain an arbitrary fuse blowing characteristic that meets the needs of the market.

SUMMARY OF THE INVENTION An object of the present invention is to provide a solid electrolytic capacitor with a built-in fuse, which can easily obtain any fusing characteristics, is easy to handle and is not easily damaged, and can simplify the manufacturing process.

[0006]

The solid electrolytic capacitor with a built-in fuse of the present invention is mounted on a thin, rectangular insulating substrate.
Formed into a rectangular shape smaller than the width and length of the insulating substrate
Copper at both longitudinal ends of the fuse element made of solder alloy
Electrodes are formed, and copper electrodes at both ends are connected in series by soldering between the cathode conductive layer and the cathode terminal of the capacitor element or between the anode lead and the anode terminal.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a central sectional view of a tantalum solid electrolytic capacitor with a built-in fuse of a chip type according to an embodiment of the present invention. FIG. 2 is a plan view of the fuse element used in the present invention, and FIG. 3 is a sectional view taken along the line AA of FIG. First rectangular in thickness 0.1mm approximately thin polyimide in FIG. 2
Depositing a solder alloy on the insulating substrate 6 in shape, number μm is deposited by sputtering or the like, contact width of the solder alloy insulating substrate 6
Copper is deposited on the both ends in the longitudinal direction of the fuse element 7 formed in a rectangular shape smaller than the length and has a thickness of several μm by vapor deposition, sputtering or the like. Here, the fusing characteristics of the fuse are determined by the composition ratio, film thickness, and pattern shape of the solder alloy. The electrode A8 of the fuse element 7 is connected to a part of the surface of the cathode conductive layer of the capacitor element 1 by solder A9, and the electrode B10 is connected to a part of the cathode terminal 4 by solder B11. On the other hand, the tantalum wire 2 embedded in the capacitor element 1 is connected to the anode terminal 3 by resistance welding or the like. As described above, the terminal contact capacitor element 1 is protected by the exterior insulating cover 5 such as epoxy resin. In this case, a solid electrolytic tantalum capacitor with a built-in fuse connected between the cathode layer and the cathode terminal of the capacitor element is obtained. In the present embodiment,
Element 7 is formed smaller than the width and length of the insulating substrate 6.
In the width direction of the fuse element and the capacitor element 1
And high insulation properties. Further, the fuse element 7
Because copper electrodes A8 and B10 are formed at both ends
Connect the fuse element to the capacitor element and the cathode terminal with solder
The fuse element 7 can be prevented from being blown.
can get.

First, in FIG. 2, a solder alloy or the like is deposited on an insulating substrate of about 0.1 mm of polyimide or the like by vapor deposition, sputtering or the like to form a fuse element 7 in a desired shape. Next, copper or the like is formed on both ends of the fuse element 7 for use as an electrode by vapor deposition, sputtering, or the like to a thickness of several μm. Here, the fusing characteristics of the fuse are determined by the composition ratio, film thickness, and pattern shape of the solder alloy. The electrode A8 of the fuse element 7 has a solder A9 on a part of the surface of the cathode conductive layer of the capacitor element 1.
The electrode B10 is connected to a part of the cathode terminal 4 with solder B
11 is connected. On the other hand, the tantalum wire 2 embedded in the capacitor element 1 is connected to the anode terminal 3 by resistance welding or the like.
The capacitor element 1 thus connected to the terminal is protected by an exterior insulating case 5 made of epoxy resin or the like. In this case, a fuse-equipped solid electrolytic tantalum capacitor having a fuse connected between the cathode layer and the cathode terminal of the capacitor element is obtained.

FIG. 4 is an internal plan view of a self-standing type tantalum solid electrolytic capacitor with built-in fuse of a resin exterior type having lead terminals according to another embodiment of the present invention. FIG. 5 is FIG.
It is arrow sectional drawing. 2 and 3 are used as in the case of the chip type. Referring to FIG. 5, the electrode A8 at one end of the fuse element 7 is connected to the surface of the cathode conductive layer of the capacitor element 1 by solder A9. The other end electrode B10 is connected to the cathode terminal 4 by the solder B11. Subsequent steps are the same as in the first embodiment, and the second embodiment is completed.

In each of the above-described embodiments, the fuse element is connected between the cathode layer and the cathode terminal of the capacitor element. However, the purpose can be achieved by inserting a fuse element between the anode lead and the anode terminal of the capacitor element. can do.

Although the tantalum solid electrolytic capacitor has been described in the first and second embodiments, it goes without saying that a similar effect can be obtained even in the case of a solid electrolytic capacitor using a metal powder exhibiting a valve action. No.

[0012]

[Effect of the Invention] As described above, the present invention has a rectangular shape.
Copper electrodes are connected to both ends of the insulating substrate, and the insulating substrate
By incorporating a fuse element in which a rectangular fuse having a smaller length and width is formed, the following effects are obtained. (1) A solid electrolytic capacitor incorporating a fuse having an arbitrary fusing characteristic can be easily obtained. (2) Since the fuse is in the form of a film, it is easy to handle and the fuse element is not easily damaged. (3) Hugh when connecting the fuse to the capacitor element
Is connected to the capacitor element via the copper electrode.
The fuse can be prevented from being blown, and there is no need to apply an insulator to avoid the connection between the fuse and the capacitor element , thereby simplifying the process.

[Brief description of the drawings]

FIG. 1 is a central sectional view of one embodiment of the present invention.

FIG. 2 is a plan view of a fuse used in the present invention.

FIG. 3 is a sectional view taken on line AA of FIG. 2;

FIG. 4 is a plan view showing the inside of another embodiment of the present invention.

FIG. 5 is a sectional view taken along the line AA of FIG. 4;

FIG. 6 is a central sectional view of an example of a conventional solid electrolytic capacitor with a built-in fuse.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Tantalum wire (anode lead) 3 Anode terminal 4 Anode terminal 5 Exterior insulating case 6 Insulating substrate 7 Fuse element 8 Electrode A 9 Solder A 10 Electrode B 11 Solder B 21 Insulating resin 22 Solder A 23 Solder B

Claims (2)

(57) [Scope of request for utility model registration] 1. A insulating the rectangular insulating substrate a thin Enmoto
Solder formed in a rectangular shape smaller than the width and length of the board
Copper electrodes are formed at both ends of the gold fuse element in the longitudinal direction.
Forms, built-in fuse type solid electrolytic capacitor, characterized in that the solder connection in series between the cathode conductive layer and the cathode terminal of the copper electrode capacitor element the both ends. Wherein insulating the rectangular insulating substrate a thin Enmoto
Solder formed in a rectangular shape smaller than the width and length of the board
Copper electrodes are formed at both ends of the gold fuse element in the longitudinal direction.
Forms, built-in fuse type solid electrolytic capacitor, characterized in that the solder connection in series between the anode lead and the anode terminal of the copper electrode capacitor element the both ends.