JPS6240430Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a leadless chip electrolytic capacitor such as a chip-type electrolytic capacitor in which an electrolytic capacitor element is sealed inside an exterior body made of synthetic resin, and face bonding electrodes are formed on the end face of the exterior body. Regarding electrolytic capacitors.

Conventionally, leadless electrolytic capacitors have an electrolytic capacitor element enclosed in a cylindrical outer case molded from synthetic resin, and cap-shaped terminals electrically connected to the electrodes of the electrolytic capacitor element at both ends of the outer case. Some have a structure in which the opening is sealed.

In such electrolytic capacitors, the airtightness of the outer container is ensured by cap-shaped terminals attached to both ends of the outer container, so there is a risk that the air-tightness cannot be maintained sufficiently. Because the electrolyte impregnated in the electrolytic capacitor element comes into direct contact with the cap terminal, it is necessary to use an expensive cladding material with aluminum on the inside and solderable metal on the outside to prevent corrosion. It had the disadvantage of being expensive.

Therefore, this idea uses only synthetic resin to ensure the airtightness of the exterior body that encloses the electrolytic capacitor element impregnated with electrolyte, and also enables face bonding by attaching solderable cap-shaped electrodes. be.

In other words, the leadless electrolytic capacitor of this invention has the leads connected to the electrode foil drawn out to both ends, an electrolytic capacitor element impregnated with an electrolytic solution, and a recess corresponding to the outer shape of the electrolytic capacitor element. an exterior body in which an electrolytic capacitor element is enclosed in a storage space formed by a concave portion formed by joining exterior body pieces made of thermoplastic synthetic resin;
It is provided with a cap-shaped electrode that covers the end surface of the exterior body and is fixed to the edge peripheral surface, and that leads drawn out from the end face of the exterior body are directly attached to the inner surface and electrically connected.

Hereinafter, embodiments of this invention will be described in detail with reference to the drawings.

1, 2 and 3 show a first embodiment of the leadless electrolytic capacitor of this invention.

The exterior body 2 is molded from an amorphous or crystalline thermoplastic synthetic resin such as polypropylene, noryl, nylon, polyphenylene sulfide, PBT, etc., and an electrolytic capacitor is placed in a storage space 4 formed inside the exterior body 2. Element 6 is enclosed. Exterior body 2
For example, as shown in FIG. 2, it is constructed of exterior body pieces 2A and 2B of the same shape, and a storage space 4 is formed by hollowing out a recess corresponding to the outer shape of the electrolytic capacitor element 6 on the joint surface side thereof. ing. Exterior body 2
The shape and volume of the storage space 4 are set larger than the volume of the electrolytic capacitor element 6, so as to prevent the electrolytic capacitor element 6 from being pressurized due to the deformation of the exterior body 2 during the pressurized bonding, and to prevent gas from being energized. The size should be set to alleviate the increase in internal pressure caused by the occurrence of

The electrolytic capacitor element 6 has a cathode side electrode made of etched high-purity aluminum foil, and an anode side electrode made of an aluminum foil similar to the cathode side electrode with a dielectric oxide film further formed thereon, with separator paper interposed therebetween. They are stacked, rolled, and impregnated with electrolyte. This electrolytic capacitor element 6
Internal leads 8, 1 individually connected to each electrode foil of
0 is drawn out from each end face of the electrolytic capacitor element 6.

This electrolytic capacitor element 6 is connected to each exterior body piece 2.
A, 2B is stored inside the storage space 4, and the internal leads 8, 10 of the electrolytic capacitor element 6 are pulled out in advance between the joint surfaces of both exterior body pieces 2A, 2B, and the joint surfaces of each exterior body piece 2, 2B are Overlap both exterior body pieces 2
Heat welding or ultrasonic welding is performed while applying pressure to A and 2B.

Each cap-shaped electrode 12, 14 is formed from a solderable metal plate or a metal plate whose surface is made of solderable metal, into the shape of a rectangular tube with one side closed. As shown in FIG. 3, internal leads 8, 10 are directly attached to the caps by welding, and each internal lead 8, 10 is electrically connected to the cap-shaped electrodes 12, 14. The cap-shaped electrodes 12 and 14 to which the internal leads 8 and 10 are connected in this manner cover the end surface of the exterior body 2 and are fixed to the edge surface of the exterior body 2 by crimping the peripheral surface thereof.

With the above configuration, the electrolytic capacitor element 6 is sealed inside the storage space 4 of the exterior body 2,
Its airtightness is ensured by the synthetic resin forming the exterior body 2. The cap-shaped electrodes 12 and 14 are electrically connected to internal leads 8 and 10 drawn out from the electrolytic capacitor element 6, and form terminals for external connection of the electrolytic capacitor element 6.

For this reason, the cap-shaped electrodes 12 and 14 do not need to be formed with any consideration given to airtightness, unlike conventional cap-shaped electrodes, and since they do not come into contact with the electrolyte, there is no corrosion, etc., and they can be made of solderable metal. It can be formed by Therefore, it is possible to produce an electrolytic capacitor at a lower cost than when a clad material or the like is used.

In the case of the embodiment described above, the exterior body 2 and the cap-shaped electrodes 12, 14 were formed into a rectangular cylindrical shape for the sake of mounting stability during face bonding, but in the case of the second embodiment shown in FIG. The same effect can be obtained even if the cap-shaped electrodes 12 and 14 are formed into a cylindrical shape.

Further, as in the third embodiment shown in FIG.
By crimping the peripheral surface of the cap-shaped electrodes 12 and 14, the fixing strength of the cap-shaped electrodes 12 and 14 to the exterior body 2 can be increased.

In addition, although the exterior body 2 in this embodiment is made of a single layer of synthetic resin, it can also be made of other synthetic resins such as a thermosetting synthetic resin layer in order to further improve airtightness. is not limited to a single layer.

As explained above, according to this invention, an electrolytic capacitor element impregnated with an electrolyte is enclosed in a synthetic resin exterior body, and the cap-shaped electrode is used for electrical connection to maintain airtightness. Since it is not used and there is no contact with an electrolyte, it can be formed only from solderable metals, making it possible to provide an inexpensive electrolytic capacitor.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a first embodiment of the leadless electrolytic capacitor of this invention, FIG. 2 is a perspective view showing the structure of the leadless electrolytic capacitor shown in FIG. 1 before welding of the exterior body, and FIG. The figure is a sectional view of the electrolytic capacitor before the cap-shaped electrode of the leadless electrolytic capacitor shown in Fig. 1 is attached, Fig. 4 is an exploded perspective view showing the second embodiment of the leadless electrolytic capacitor of this invention, and Fig. 5 The figure is a partially cutaway side view showing a third embodiment of the leadless electrolytic capacitor of this invention. 2... Exterior body, 2A, 2B... Exterior body piece, 4...
...storage space, 6...electrolytic capacitor element, 8,1
0... Internal lead, 12, 14... Cap-shaped electrode.

Claims (1)

[Claims for Utility Model Registration] An electrolytic capacitor element impregnated with an electrolytic solution, with leads connected to electrode foil drawn out at both ends, and a thermoplastic composite formed with a recess corresponding to the external shape of the electrolytic capacitor element. an exterior body that encapsulates the electrolytic capacitor element in a storage space formed by the recess by bonding exterior body pieces made of resin; A leadless electrolytic capacitor comprising a cap-shaped electrode to which leads drawn out from the end face of the exterior body are directly attached to the inner surface and electrically connected.