JPH02116112A - Mold chip solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To enable a fuse material to be attached close to a capacitor easily and securely by joining an insulation film where the fuse material is connected to a land. CONSTITUTION:In two sets of insulation films, a fuse material 14 which is narrower than lands 17a and 17b is connected the lands 17a and 17b of each copper foil, etc., and the land 17b is joined to a cathode terminal 11b and the land 17a is connected to a capacitor element 9 through the fuse material 14 by conductive joint materials 13b and 13a, respectively. With this configuration, the fuse material can be attached close to the capacitor element easily and securely with improved heat conduction.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a molded chip solid electrolytic capacitor that has a built-in fuse to provide high safety.

Conventional technology In recent years, the use of chips for electronic components in the field of industrial equipment has progressed, and as the electronic components are required to have high reliability with added safety, molded chip solid electrolytic capacitors The same is true.

In other words, when a molded chip solid electrolytic capacitor is installed in a device with its polarity reversed,
When a solid electrolytic capacitor is loaded with power that exceeds a specified value, the capacitor element and its surrounding circuits will burn out. In order to prevent this burnout, molded chip solid electrolytic capacitors with built-in fuses are increasingly being used (Japanese Patent Application Laid-Open No. 150817/1983).

The molded chip tantalum solid electrolytic capacitor, which is the most widely used molded chip solid electrolytic capacitor among conventional molded chip solid electrolytic capacitors, will be described below.

FIG. 10 is a sectional view of a conventional molded chip tantalum solid electrolytic capacitor. In FIG. 10, 1 is a capacitor element, 2 is an insulating plate using polytetrafluoronyletine, etc., 3a is an external anode terminal, 3b is an external cathode terminal, 4
6 & 5b are conductive joints for joining the capacitor element 1 and external cathode terminal 3b to a melting member (hereinafter referred to as fuse material) 6 which melts at a predetermined temperature. 7 is a mold exterior resin made of an epoxy or silicone material, and 8 is an insulating coating layer made of an insulating coating material.

The operation of the conventional molded chip tantalum solid electrolytic capacitor configured as described above will be described below.

When a molded chip mental solid electrolytic capacitor is attached to a device with its polarity reversed, or when a power exceeding a specified value is loaded onto the capacitor, the capacitor element 1 is short-circuited. At this time, when a current flows through the fuse material 6 and the current exceeds the fusing current of the fuse material 6, the fuse material 6 melts and cuts off the current. Further, when the capacitor element 1 is overheated due to a short circuit in the capacitor element 1, the connecting portion of the fuse material 6 is destroyed and the fuse material 6 is blown out due to the overheating.

This operation prevents burnout of the capacitor element 1 and its peripheral circuits.

Problems to be Solved by the Invention However, in the conventional configuration, the fuse material 6 is separated from the capacitor element 1, and the parts other than the joint with the cathode part of the capacitor element 1 and the joint with the external cathode terminal 5b are fixed. Moreover, since the fuse material 6 itself is easily deformed, it has been difficult to sufficiently fix the fuse material 6 between the capacitor element 1 and the external cathode terminal 6b. As a result, assembly failures occurred due to the fuse material 6 falling off from the joints.

On the other hand, since the fuse material 6 is separated from the capacitor element 1 except for the joint with the capacitor element 1, when the capacitor element 1 is overheated due to a short circuit of the capacitor element 1, the heat is not transferred to the fuse material 6. Unfortunately, as a result, the fuse material 6 may not be fully fused.

Furthermore, since it is necessary to apply an epoxy-based insulating material to the capacitor element 1 in advance and dry it to form the insulating coating layer 8, steps such as coating, drying, and curing are necessary, resulting in a large number of man-hours.

The conventional configuration had the above problems.

These problems also occur when solid aluminum, solid ceramic, or the like is used as the material for the capacitor element 1.

An object of the present invention is to provide a molded chip solid electrolytic capacitor that can solve the above-mentioned conventional problems.

Means for Solving the Problems In order to solve the above problems, the molded chip solid electrolytic capacitor of the present invention includes an insulating film.

A fuse material formed on this film, and a first fuse material connected to both ends of this fuse material. and a second land,
A structure is adopted in which the insulating film and the capacitor element are brought into close contact with each other so that the first land is bonded to the cathode portion of the capacitor element.

By making a fuse sheet in advance, which is made by fixing a fuse material to an insulating film, as described above, the fuse sheet can be fixedly and closely attached to the capacitor element and external cathode terminal, thereby preventing assembly disconnection. can be prevented from occurring, and the fusing characteristics of the fuse material are stabilized.

EXAMPLE Hereinafter, as an example of the present invention, a molded chip tantalum solid electrolytic capacitor, which is most commonly used, will be described with reference to the drawings.

FIG. 1 is a sectional view of a molded chip tantalum solid electrolytic capacitor according to an embodiment of the present invention. In the same figure, 9
is a capacitor element, in which tantalum powder is molded and fired in a vacuum to form a dielectric made of an oxide film, and an electrolyte layer made of manganese dioxide is further formed on the surface of the dielectric made of the oxide film, A dark pupil layer made of carbon is laminated on this surface. 10 is an insulating plate made of polytetrafluoronyletine or the like, 111L is an external anode terminal, 11b is an external cathode terminal, 12 is an anode lead wire made of tantalum wire, 131Lg13b is a conductive bonding agent, 14 is a fuse material, and 16 is a polyimide 16 is a mold exterior resin made of an epoxy-based or silicon-based material; 17a and 17b are copper foils made on the insulating film 16; and lands formed in a predetermined pattern or on the lands. The land is plated with gold, rhodium, high-temperature solder, etc. The anode lead wire 12 is connected to the external anode terminal by means such as welding, and the fuse material 14 and the land 17& are tightly pressed to the capacitor element 9 using a conductive bonding agent 13a, and the fuse material 1
4 and the land 17b are pressurized and adhered to the external cathode terminal 11b using a conductive bonding agent 13b. Fuse material 14
A lead-based thin plate with a thickness of 30 μm to 100 μm is used, and is brought into close contact with the insulating film 16.

FIG. 2 is a plan view of the fuse seat portion of the molded chip mental solid electrolytic capacitor according to the above embodiment of the present invention, viewed from below.

The operation of the molded chip tantalum solid electrolytic capacitor configured as above will be explained below.

If a molded chip tantalum solid electrolytic capacitor is installed in a device with its polarity reversed, or if the capacitor is loaded with power exceeding the specified value, the capacitor element 9
When the fuse material 14 is short-circuited, a current flows through the fuse material 14, and when the current value exceeds the fusing current of the fuse material 14, the fuse material 14 melts and cuts off the current. Further, when the capacitor element 9 is short-circuited, the temperature of the capacitor element 9 rises, but the temperature of the capacitor element 9 is also conducted to the fuse material 14, which melts the fuse material 14 and cuts off the current.

Also, by providing this fuse seat.

The installation of the fuse material 14 is more stable than before, and assembly failures do not occur. Furthermore, since the fuse material 14 and the capacitor element 9 are in close contact with each other, the fuse material 14
can receive sufficient heat transfer from the capacitor element 9, thereby improving the thermal fusing characteristics of the fuse material 14.

The fuse sheet portion of the molded chip tantalum solid electrolytic capacitor of this example has been described only with reference to FIG. 2, but the fuse sheet is shown in FIG. 3.

As shown in FIG. 4, the fuse material 14 is bent front and back through the heat-resistant insulating film 16, and the land 17a,
It may be attached to 1yb by means such as welding.

Furthermore, FIGS. 6 and 6 also show examples of fuse sheets, which can be substituted for the fuse sheet shown in FIG. 2. In addition, in FIGS. 5 and 6, 18 is a null through which the fuse material 14 is passed.

FIG. 7 shows the fuse sheet ribbon in a state before the fuse sheet shown in FIG. 2 is cut away. 19-2
Reference numeral 2 denotes a cutting portion where the fuse sheet ribbon is cut off to form a fuse sheet, and a highly reliable fuse sheet can be obtained by this method. FIG. 8 is also a sectional view of a single chip mental solid electrolytic capacitor according to another embodiment of the present invention, which operates in the same way as the embodiment shown in FIG. FIG. 9 is a plan view of the fuse seat portion of another embodiment shown in FIG. 8, viewed from above. In this embodiment, as shown in FIG.
By increasing the width at both ends, the fuse material 14 and the capacitor element 9. Moreover, the area of the joint with the external cathode terminal 11b can be increased, and the joint strength can be increased.

In this embodiment, tantalum solid is used for the capacitor element 1, but aluminum solid or ceramic solid may also be used as the material for the capacitor element 1.

Effects of the Invention The molded chip solid electrolytic capacitor of the present invention has (1)
Since the capacitor element and the fuse material are closer together than in the past, heat from the capacitor element is easily transferred to the fuse, improving the fusing characteristics of the fuse material.

(2) Since the installation of the fuse sheet is very easy, there is no possibility of disconnection in one assembly.

(3) Since the fuse sheet is a thin piece, no appearance defects occur in the thickness direction.

(4) There is no need to insulate the capacitor element, which simplifies the process.

There are other effects.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of an embodiment of the molded chip tantalum solid electrolytic capacitor of the present invention, which is the most commonly used molded chip solid electrolytic capacitor, and Figure 2 is a plan view from the lower half of the fuse seat. 3, 4, 6, and 6 are plan views showing other embodiments of the fuse sheet, FIG. 7 is a plan view seen from above the fuse sheet ribbon, and FIG. 9 is a sectional view of another embodiment of the invention, FIG. 9 is a plan view of the fuse seat portion of FIG. 8 seen from above, and FIG. 10 is a sectional view of a conventional molded chip tantalum solid electrolytic capacitor. 9... Capacitor element, 1311, 13b... Conductive bonding material, 14...
Fuse material, 16...Heat-resistant insulating film - skewer, 16...Mold exterior resin, 17m
, 17b...land. Name of agent Patent attorney Shigetaka Awano and 1 other list Figure 1'la No. 3a/7a, I7b Rand

Claims (2)

[Claims] (1) An insulating film, a melting member formed on the film that melts at a predetermined temperature, and first and second lands connected to both ends of the melting member, the first land so that it is connected to the cathode part of the capacitor element.
A molded chip solid electrolytic capacitor, characterized in that the film is brought into close contact with the capacitor element. (2) The molded chip solid electrolytic capacitor according to claim 1, wherein the width of the first and second lands is wider than the width of the melting member.