JPS6228753Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a chip-type electrolytic capacitor, and in particular, when the chip-type electrolytic capacitor is soldered onto a board together with other chip components, the capacitor chip will not be damaged by heat. This article relates to a chip-type electrolytic capacitor with a heat-resistant structure.

In recent years, automatic mounting of electronic components onto printed circuit boards has progressed, and electronic components, both active and passive, are becoming more and more chipped. Chip-based capacitors, such as aluminum electrolytic capacitors, are also progressing.

In general, electrolytic capacitors have two types of structures: those in which the counter electrode is an electrolytic solution, and those in which an oxide such as MnO ₂ is used as the counter electrode. If the counter electrode is an electrolytic solution, the electrode foil and separator paper are stacked and wound to form a capacitor element, and the capacitor element is impregnated with the electrolyte and stored in an exterior case (a metal case made of aluminum, etc.). It is formed by sealing the opening of the outer case with an elastic sealing body or a sealing terminal plate.

A conventional chip type electrolytic capacitor is constructed as shown in FIG. A capacitor element 2 is housed inside a metal case 1, and an anode lead 3 is drawn out from the element 2 through a sealing rubber packing 4. Further, the cathode is welded from the capacitor element 2 to the inner surface or inner bottom surface of the case using the welding tab 5, and is drawn out to the outer surface of the metal case by welding a cathode lead 6 to the outer bottom surface of the case. After external electrodes 7 and 8 are welded to the anode lead 3 and cathode lead 6, respectively, the outer periphery of the capacitor is covered with an insulating resin 9.

However, when mounting conventional chip-type electrolytic capacitors on a printed circuit board, the capacitor
Because the chip and other circuit chips are immersed in a solder solution with a temperature of approximately 270°C, when the chip is immersed for 10 seconds, the internal pressure rises due to the electrolyte vapor and air inside the metal case, causing the sealing rubber to rise.・There was a drawback that the packing was extruded and the exterior resin was cracked or cracked. As a countermeasure to this problem, we tried to lower the vapor pressure of the electrolyte, but there was a problem in that even a slight increase in internal pressure caused by the high temperature during the soldering bath would cause the rubber packing to be pushed out.

The present invention has been developed in view of the above-mentioned points, and includes a case in which a capacitor element is housed in a case having an opening on one or both sides, and the opening of the case is sealed with a sealing member such as rubber packing. A space surrounded by the case is provided at the case opening, an electrode is drawn out from the capacitor element to the outside of the case to form a capacitor structure, and the outer periphery of the capacitor is covered with an insulating resin. The resin increases the strength of the seal at the case opening, and even if it is immersed in a high-temperature solder bath during mounting, the seal will not be pushed out by the internal pressure inside the case and cause cracks or cracks in the exterior resin. The purpose of this invention is to provide a chip-type electrolytic capacitor with excellent heat resistance.

Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a cross-sectional view showing the first embodiment of the chip-type electrolytic capacitor according to the present invention, and FIG. 3 is a cross-sectional view showing the internal capacitor of this chip-type electrolytic capacitor before being covered with an insulating resin. be. In this embodiment, the internal capacitor is a terminal bidirectional capacitor.

In FIGS. 2 and 3, an opening A is shown on one side.
A capacitor element 12 is housed inside a metal case 11 having a metal case 11, and an opening A of this case 11 is filled with an elastic sealing member 13 such as rubber packing.
The case 11 is sealed by drawing.
In this case, as shown in FIG. 3, a space 14 is provided that extends from the case opening A to the curled portion B of the metal case 11. An anode lead 15 passes through the elastic sealing body 13 from the capacitor element 12, and a welding tab 1 passes through the cathode side from the capacitor element 12.
6 to the inner side surface or inner bottom surface of the case, and the cathode lead 17 is welded to the outer bottom surface C of the metal case. After external electrodes 18 and 19 are welded to the anode lead 15 and the cathode lead 17, respectively, the outer periphery of this electrolytic capacitor is covered with an insulating resin 20 and made into a chip.

In such a configuration, a space 14 is formed in the curled portion B between the case opening A and the elastic sealing body 13, and the insulating resin 2 is filled in this space 14 when the case is packaged.
0 and is packaged, the insulating resin 20 fixes the elastic sealing body 13 and seals the case opening A. Therefore, even if the internal pressure inside the case increases when it is immersed in a high-temperature solder bath during mounting, the force that pushes out the elastic sealing body 13 can be suppressed.
Cracks and cracks will not occur in the insulating resin 20. FIG. 4 is a sectional view showing a second embodiment of the present invention, and FIG. 5 is a sectional view showing the internal capacitor before being covered with insulating resin. In this embodiment, the internal capacitor is a terminal-unidirectional capacitor.

4 and 5, similarly to the first embodiment, the metal case 11 has an opening A on one side,
The capacitor element 12 is housed inside the case, the case opening A is filled with an elastic sealing member 13 such as rubber packing, and the case 11 is sealed by drawing. In this case, as shown in FIG. 5, from the case opening A to the curled part B of the metal case 11
A space 14 surrounded by a metal case 11
will be provided. An anode lead 15 and a cathode lead 16 are connected to the elastic sealing body 13 from the capacitor element 12.
a penetrates and is led out to the outside of the sealing body. Further, an external electrode 18 is welded to the anode lead 15, and the cathode lead 16a is extended from the opening A to the bottom side of the case, bypassing the outside of the case, and an external electrode 19 is welded thereto. After arranging the electrodes in this manner, the outer periphery of this electrolytic capacitor is covered with an insulating resin 20 to form a chip.

In such a configuration, similarly to the first embodiment, a space 14 is formed across the case opening A and the curled portion B between the elastic sealing member 13, and the insulating resin 20 is filled in this space 14 during exterior packaging. Entered and exteriorized. Therefore, the insulating resin 20 is
At the same time, the elastic sealing body 13 is fixed, and even if the internal pressure inside the metal case increases due to the high temperature during the solder bath, the force pushing out the sealing body 13 can be suppressed, and the outer resin 20 No more cracks or cracks.

FIG. 6 is a diagram showing another embodiment of FIG. 5.

In this figure, the curled part B of the metal case is
is squeezed into a conical shape in the direction of the case opening A.
Even if the capacitor structure is molded in this manner before being packaged with insulating resin, a chip-type electrolytic capacitor having the same degree of sealing as the capacitor shown in FIG. 4 can be realized. The curl shape shown in FIG. 6 can also be used in the double terminal type capacitor shown in FIG. 2 to achieve the same effect.

Note that in the first and second embodiments, the capacitor element 12
Although a case has been described in which the capacitor element 12 is housed in a case 11 having an opening on one side, the present invention is not limited thereto. For example, as shown in FIG. An opening A, a curled part B, a sealing body 13, and a space 14 are formed on the cathode side, and an internal capacitor is formed by drawing out the cathode lead 16a, and the outer periphery of this capacitor is covered with an insulating resin. May be externally packaged.

Further, in the above embodiment, the entire outer periphery of the internal capacitor is covered with insulating resin 20 to form a chip type capacitor, but a structure may be adopted in which the entire outer periphery is not covered and a part of the case is exposed.

As described above, according to the present invention, a capacitor element is housed in a case, the opening of the case is sealed with a sealing member, and at the same time, a space surrounded by the case is provided between the sealing member and the case opening, and a space is provided outside the case. The electrolytic capacitor has a structure in which the electrodes are drawn out, and the outer periphery of the electrolytic capacitor is covered with an insulating resin, so that the insulating resin enters the space after the packaging, sealing the case opening and sealing the case opening. The sealing body can be fixed, and even if a capacitor chip manufactured in this way is immersed in a high-temperature solder bath, the sealing body will be pushed out by the internal pressure inside the case, causing cracks or cracks in the exterior resin. This has the advantage that there will be no problems.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the structure of a conventional chip electrolytic capacitor, Fig. 2 is a sectional view showing a first embodiment of the chip electrolytic capacitor of the present invention, and Fig. 3 is an internal capacitor of the capacitor shown in Fig. 2. 4 is a sectional view showing the second embodiment of the chip-type electrolytic capacitor of the present invention. FIG. 5 is a sectional view showing the structure of the internal capacitor of the capacitor shown in FIG. 4. Figure 5 is a sectional view showing another embodiment of Figure 5;
FIG. 7 is a sectional view showing another embodiment of the case shape and the lead position. 11, 21... Case, 12... Capacitor element, 13... Sealing body, 14... Space, 15...
Anode lead, 16a, 17...Cathode lead, 1
8, 19...External electrode, 20...Insulating resin, A
...opening part, B...curl part.

Claims (1)

[Scope of utility model registration request] A capacitor element is housed in a case having an opening on one or both sides, the case opening is sealed with a sealing body, and at the same time, a space surrounded by the case is formed between the sealing body and the case opening, A chip type electrolytic capacitor comprising an electrolytic capacitor having a structure in which electrodes are drawn out from the capacitor element to the outside of the case, and a part or all of the outer periphery of the electrolytic capacitor is covered with an insulating resin.