JPH03295218A - Solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To obtain the small-sized title capacitor having a small number of component parts by a method wherein one of an anode terminal and a cathode terminal is formed with fuse material. CONSTITUTION:A chip type solid electrolytic capacitor 1 has a capacitor element 2, an anode lead 3 is led out from the capacitor element 2, and an anode terminal 4 is connected to the anode lead 3 by welding. Also, a cathode terminal 5 is connected to the cathode part of the capacitor element 2 at the stepped part 6 through the intermediary of a conductive bonding agent 9, and the entire capacitor element 2 is covered by resin material 7. The cathode terminal 5 consists of a plate of fuse material, and it has a constricted part 8 in the midway. The fuse material is made of an alloy of Pb, Sb, Sn, Ag and the like, for example. The condition of fusing can be set by the sizes A and B in the neighborhood of the constricted part in addition to the composition and plate thickness of the fuse material. When an over current flows, the terminal itself, consisting of fusing material, is fused.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid electrolytic capacitor, particularly a solid electrolytic capacitor with a fuse.

[Conventional technology 1 Solid electrolytic capacitors such as tantalum solid electrolytic capacitors are used in consumer and industrial equipment, but if a solid electrolytic capacitor were to break down, a large short-circuit current would flow and the capacitor element would be damaged. There is a risk of heat generation, burnout, and equipment damage.

Therefore, solid electrolytic capacitors with fuses are known. In other words, in a solid electrolytic capacitor in which a capacitor element is connected to an anode lead terminal and a cathode lead terminal and is coated with resin, the cathode lead terminal is connected to the cathode part of the capacitor element via an insulator, and the cathode lead terminal and the cathode of the capacitor element are connected to each other. The parts are connected by a fuse (for example, Japanese Utility Model Application No. 63-16432).

[Problems to be Solved by the Invention] However, a solid electrolytic capacitor having such a fuse becomes thicker due to the provision of the fuse, and therefore the solid electrolytic capacitor becomes larger and the number of parts increases. There is a drawback.

An object of the present invention is to provide a solid electrolytic capacitor with a fuse that is small in size and has a small number of parts, and a method for manufacturing the same.

[Means for Solving the Problems] In order to achieve this object, the solid electrolytic capacitor of the present invention has the following features:
At least one of the anode terminal and the cathode terminal is made of a fuse material.

A constriction may be formed in the terminal made of fuse material.

In addition, in the method of manufacturing such a solid electrolytic capacitor, after the anode lead pulled out from the anode body is fixed to the frame of the first hoop material that becomes the anode terminal, the anode body is subjected to chemical conversion, thermal decomposition, and cathode attachment. A step of subjecting the capacitor element to each treatment, a step of connecting a cathode terminal made of a fuse material fixed to a second hoop material to the cathode part of the capacitor element, a step of forming a resin exterior on the capacitor element, and a step of forming an anode terminal and a cathode terminal. The outer end of the hoop material is cut off from each hoop material, and each terminal is bent as necessary.

Further, the method further includes the step of forming a recessed portion and, if necessary, forming a stepped portion, before connecting the cathode terminal made of the fuse material fixed to the second hoop material to the cathode portion of the capacitor element. You may also do so.

[Function] When an overcurrent flows, the terminal itself, which is made of fuse material, melts. The fusing conditions are determined not only by the composition and thickness of the fuse material but also by the dimensions of the constriction, if any.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 6.

<Embodiment 1> A first embodiment according to the present invention is shown in FIG. 1 and FIG. 2.

A chip-type solid electrolytic capacitor 1 has a capacitor element 2, an anode lead 3 is drawn out from the capacitor element 2, and an anode terminal 4 is connected to the anode lead 3 by a condenser connection. In addition, a cathode terminal 5 is provided at the cathode portion of the capacitor element 2.
are connected at the stepped portion 6 via a conductive adhesive 9, and the entire capacitor element 2 is covered with a resin material 7.

The capacitor element 2 is made of a sintered body obtained by sintering tantalum powder, and the anode lead 3 is made of a tantalum wire. An oxide film and a manganese dioxide layer are formed on the surface of the sintered body, and carbon, a silver layer film, and solder are sequentially formed as supporting rings to form a cathode part. Connected by

The cathode terminal 5 is made of a fuse plate and has a constriction 8 in the middle.
is formed. The fuse material is, for example, Pb, Sb,
It is made of an alloy such as Sn and Ag.

The fusing conditions can be varied depending on the composition and plate thickness of the fuse material as well as the dimensions A and B (third section) near the constriction. Here are some examples.

Example 1 In the case of a tantalum solid electrolytic capacitor with a rated voltage of 35 V and a rated capacity of 10 μF, the composition of the fuse material is Pb99.6% 5b-0.4% Plate thickness 0.1 mm Dimension A 2.5 mm Dimension B 1. Omm Fuses in 10 seconds at 35V, 5A.

Example 2 In the case of a tantalum solid electrolytic capacitor with a rated voltage of 20 V and a rated capacity of 6.8 μF, the composition of the fuse material is Pb 95% Sn 5% Plate thickness 0.1 mm Dimension A 2.2 mm Dimension B 0.8 mm 20V, 4At'5 seconds To melt.

Example 3 In the case of a tantalum solid electrolytic capacitor with a rated voltage of 25 V and a rated capacity of 1.5 μF, the composition of the fuse material is Pb 93% Ag 7% Plate thickness 0.1 mm Dimension A 2.2 mm Dimension B 0.6 mm 25V, 3A-? 'It will melt in 5 seconds.

Example 4 In the case of a tantalum solid electrolytic capacitor with a rated voltage of 25 V and a rated capacity of 0.47 μF, the composition of the fuse material is Pb 99% Sn 1% Plate thickness 0.1 mm Dimension A 1.2 mm Dimension B 0.5 mm In 5 seconds at 25 V and 3 A To melt.

FIGS. 4 and 5 show a method for manufacturing the solid electrolytic capacitors shown in FIGS. , while the hoop material 10, which will become the anode terminal 4, is fixed by welding to the frame 11, chemical formation (forming an oxide film on the surface of the sintered body), thermal decomposition (formation of a manganese dioxide layer), and cathode attachment (carbon, The capacitor element 2 is formed by performing various processes such as forming a silver layer film and forming a solder cylinder. Note that the hoop material 10, particularly the frame 11, is made of an iron plate plated with nickel.

On the other hand, a constricted portion 8 and a stepped portion 6 are formed in the cathode terminal 5 made of a fuse material and connected to the hoop material 12 by welding.

After the cathode part of the capacitor element 2 is connected to the step part 6 of the cathode terminal 5 by the silver botting method, it is covered with a resin material 7 and cut at locations C and D at the outer ends of both terminals. After that, the anode terminal and the cathode terminal are bent onto the bottom surface of the exterior body.

<Example 2> FIG. 6 shows a second embodiment of the invention.

The structure of the dip-type fixed electrolytic capacitor 13 is as shown in Example 1.
Embodiment 1 is almost the same as Embodiment 1 except that the anode terminal 4 and the cathode terminal 5 are pulled out, the cathode terminal 5 is not provided with a step, and the constriction 8 is located inside the exterior body.
different from.

In Examples 1 and 2, only the cathode terminal is made of a fuse material, but the anode terminal may be made of a fuse material, or both the cathode terminal and the anode terminal may be made of a fuse material.

Also, it is easier to determine the fusing conditions if a constriction is provided, but
You don't have to.

[Effects of the Invention] As explained above, according to the present invention, since the terminal itself is made of fuse material, the thickness of the solid electrolytic capacitor can be reduced, and the solid electrolytic capacitor can therefore be made smaller. Furthermore, since the terminal itself is made of a fuse material, there are advantages such as there being no need to prepare a separate fuse or provide an insulating section between the cathode section and the terminal.

Furthermore, when a constriction is provided, there is an advantage that it becomes easier to determine the fusing conditions.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of one embodiment of the solid electrolytic capacitor of the present invention, FIG. 2 is a side view thereof, FIG. 3 is a section showing the vicinity of the constriction of the terminal, and FIG. 4 is a solid electrolytic capacitor of the present invention. FIG. 5 is a plan view showing part of the manufacturing process, FIG. 5 is a side view thereof, and FIG. 6 is a diagram showing another embodiment of the solid electrolytic capacitor of the present invention. In the figure, 1... solid electrolytic capacitor, 2... capacitor element, 3... anode lead, 4... anode terminal, 5...
...Cathode terminal, 6...Step part, 7...Resin material, 8...
・Neck part, 10... hoop material (first hoop material),
DESCRIPTION OF SYMBOLS 11... Frame, 12... Hoop material (second hoop material), 13... Solid electrolytic capacitor.

Claims (4)

[Claims] (1) A solid electrolytic capacitor formed by connecting an anode terminal and a cathode terminal to a capacitor element and sheathing them with resin, characterized in that at least one of the anode terminal and the cathode terminal is formed of a fuse material. (2) The solid electrolytic capacitor according to claim 1, wherein a constricted portion is formed in the terminal formed of a fuse material. (3) After fixing the anode lead pulled out from the anode body to the frame of the first hoop material that will serve as the anode terminal, the process of subjecting the anode body to chemical conversion, pyrolysis, and cathode attachment;
A step of connecting a cathode terminal made of fuse material fixed to a second hoop material to the cathode part of the capacitor element, a step of forming a resin sheath on the capacitor element, and a step of connecting the outer ends of the anode terminal and the cathode terminal to each hoop. A method for manufacturing a solid electrolytic capacitor comprising the steps of cutting the material, cutting it out, and bending each terminal as necessary. (4) Prior to connecting the cathode terminal made of the fuse material fixed to the second hoop material to the cathode portion of the capacitor element, the method further includes the step of forming a recessed portion and further forming a stepped portion if necessary. The method for manufacturing a solid electrolytic capacitor according to claim 3.