JPS608425Y2 - Chip type aluminum electrolytic capacitor - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a chip-type aluminum electrolytic capacitor.

Recent advances in electronic circuits and systems have created a need for the development of chip-type capacitors that have maximum capacitance per unit volume by minimizing external terminals and have an external shape that allows automatic mounting on circuit boards.

Tantalum solid electrolytic capacitors and ceramic capacitors have conventionally been put into practical use as capacitors with the above-mentioned characteristics, but in the case of aluminum electrolytic capacitors in which a paste-like electrolyte is soaked into the capacitor element, the It is extremely difficult to mold with synthetic resin because the electrolyte is attached to the surface, and the molding temperature is 150~2.
Since high heat of 00°C is applied directly to the element, the dielectric oxide film deteriorates, and since the exterior resin is permeable, the electrolyte loses permeation, making the electrical characteristics of the capacitor unstable.

Furthermore, since aluminum electrolytic capacitors are impregnated with electrolyte, they cannot be used if solderable metals such as tantalum solid electrolytic capacitors are used as terminals because they will corrode.

Therefore, in order to convert aluminum electrolytic capacitors into chip capacitors, the exterior structure and terminal derivation remain issues.

5 The present invention was developed in view of the above-mentioned circumstances, and is a method of housing a capacitor element in a bottomed cylindrical container made of a valve-acting metal and having a bottom cap made of a solderable metal on the outer bottom surface. The opening of the container is sealed with an elastic sealing plug, a resin coating is provided on the opening of the container and the outer peripheral side of the container, and a top cap made of a solderable metal is placed on the top of the closing plug to prevent dielectric oxidation. The present invention aims to provide a chip-type aluminum electrolytic capacitor with stable electrical characteristics without film deterioration or electrolyte permeation loss.

Embodiments of the present invention will be described below with reference to the drawings.

That is, as shown in FIG. 1, a capacitor element 1 impregnated with an electrolytic solution is housed in a bottomed cylindrical container 2 made of a valve metal such as aluminum, titanium, or an alloy thereof.

The cathode lead terminal 3 of the capacitor element 1 is connected to the inner bottom surface of the container 2 by welding or the like.

Further, a bottom cap 4 made of a solderable metal such as copper, iron, nickel, or an alloy thereof is placed on the outer bottom surface of the container 2 and fixed together by a method such as pressure welding or welding.

The anode lead-out terminal 5 of the capacitor element 1 is passed through the terminal insertion hole of an elastic sealing plug 6 made of rubber, elastomer, synthetic resin, etc. that seals the opening of the container 2, and the opening of the container 2 is pressed from the outside. Tighten the edges and seal.

Tetrafluoroethylene-hexafluoropropylene copolymer, trifluorochloroethylene, A resin coating 7 made of a highly heat-resistant and heat-shrinkable resin tube or resin film made of vinylidene chloride or polyester is placed on the container 2 and then heated and shrunk with a hot gun or the like to tightly adhere the container 2 .

That is, an upper surface cap 9 made of a solderable metal such as copper, iron, nickel, or an alloy thereof and having a through hole through which the lead wire 8 at the tip of the anode extraction terminal 5 is passed is placed over the elastic sealing plug 6. .

The inner surface of the upper cap 9 may be coated with an electrically insulating adhesive such as epoxy resin or silicone resin.

Then, the tip of the lead wire 8 is welded to the top cap 9,
They are fixed together by soldering or caulking, and are electrically connected.

If either the bottom cap 4 or the top cap 9 is made of a ferromagnetic metal such as iron or nickel, polarity can be easily determined during automatic mounting on a circuit board.

Further, as shown in FIG. 2, the same effect can be achieved by directly fixing the tip of the anode lead-out terminal 5 to the upper cap 9 without connecting a lead wire to the anode lead-out terminal 5.

In the above embodiment, the cathode lead terminal 3 is connected to the inner bottom surface of the container 2, and the anode lead terminal 5 is led out through the elastic sealing plug 6 that seals the opening of the container 2. An anode lead-out terminal may be connected to the inner bottom surface and a cathode lead-out terminal may be led out through the elastic sealing plug 6.

Further, an explosion-proof valve consisting of a groove or a groove may be provided on the outer periphery of the side surface or the bottom surface of the container 2.

The chip-type aluminum electrolytic capacitor configured as described above is sealed using a container 2 made of a valve metal, so there is no loss due to permeation of the electrolyte unlike with a resin exterior, and the capacitor is made of a metal that can be soldered. Since the bottom cap 4 and the top cap 9 are provided, soldering connection to the circuit board becomes easy.

In addition, since it is small and cylindrical, there is no directionality and it is easy to automatically mount it on a circuit board.If either the bottom cap 4 or the top cap 9 is made of a ferromagnetic material such as iron or nickel, polarity can be easily determined. Not only is this possible, but the polarity can be detected using magnets, so there is no need to secure the product with tape or store it in a magazine during shipping, and it can be shipped by simply packing it into a bag.

Furthermore, existing equipment such as assembly equipment can be used as is, there is no need for special large-scale equipment, and the electrical performance does not deteriorate even at high temperatures during soldering during automatic mounting on circuit boards. A chip-type aluminum electrolytic capacitor with stable characteristics can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a chip-type aluminum electrolytic capacitor according to one embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a chip-type aluminum electrolytic capacitor according to another embodiment of the present invention. 1... Capacitor element, 2... Container,
3. Bent cathode lead terminal, 4... bottom cap,
5...Curved anode lead-out terminal, 6...Elastic sealing plug, 7
...Curved edge covering, 8...Lead wire, 9...
...Top cap.

Claims (2)

[Scope of utility model registration request] (1) a capacitor element impregnated with an electrolytic solution and having an anode lead-out terminal and a cathode lead-out terminal; a bottomed cylindrical container made of a valve metal that houses the capacitor element and has the cathode lead-out terminal connected to the inner bottom surface; a bottom cap made of solderable metal that covers the outer bottom of the container; an elastic sealing stopper that seals the opening of the container; and an opening and an outer peripheral side of the container that are not covered by the bottom cap. A chip-type aluminum electrolytic capacitor comprising: a resin coating that covers the elastic sealing plug; and a top cap made of a solderable metal that covers the top of the elastic sealing plug and connects the anode lead terminal. (2) Utility Model Registration A chip-type aluminum electrolytic capacitor according to claim (1), characterized in that the bottom cap or the top cap is made of a ferromagnetic material such as iron or nickel.