JPS626676Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved chip electrolytic capacitor.

Generally, electrolytic capacitors are made by etching high-purity aluminum foil to expand its surface area, then applying chemical conversion treatment to form an oxide film on the aluminum foil, using the aluminum foil as an electrode foil, and cutting the electrode foil into specified dimensions. After that, as shown in FIG. 1, the external lead terminals 2 are connected to the electrode foils 1 and 1' for the anode and the cathode by caulking or the like, and the capacitor element 4 is wrapped around the electrolytic paper 3. Form. Next, the capacitor element 4 is impregnated with an electrolytic solution, and the lead terminal 2 is passed through a sealing body 5 having elasticity such as rubber packing, and a case 6 made of aluminum, resin, etc.
The opening end of the case 6 was sealed by winding or the like.

With recent advances in circuit technology, various problems have arisen with electrolytic capacitors manufactured using the manufacturing method described above, and the current state of the electrolytic capacitor industry is that these improvements are being forced. .

In particular, in terms of characteristics, there is a reduction in leakage current, improvement in reliability, and in terms of cost, there is a simplification of the manufacturing method, and there are countless other improvements such as miniaturization and large capacity.

Many electronic devices are also trending toward miniaturization, and costs have been reduced through automatic insertion of components in wiring such as printed circuit boards.There is also a demand for electrolytic capacitors that can be automatically inserted and miniaturized. This is not an exception. In particular, in the case of cylindrical shapes, they are manufactured by winding electrode foil, which increases the height dimension, but electronic devices are required to be thinner.
Thinking in the opposite direction is being taken up as a major research topic.

Furthermore, it is well known that electrolytic capacitors use a larger number of parts and materials than other electronic components, resulting in higher manufacturing costs and higher prices.

The present invention aims to solve many of the problems mentioned above and to provide a chip-type electrolytic capacitor that is inexpensive and highly productive.

The present invention will be described below with reference to embodiments shown in FIGS. 3 to 6.

As is well known, there are many theories as to the cause of leakage current. Among these causes, the microcurrent factor that flows when repairing a destroyed oxide film is one of the major causes of leakage current. Figure 3 shows experimental data regarding the destruction of this oxide film. A test piece of etched and chemically formed high-purity aluminum foil (a) with an intact surface and an unetched and unformed part at the cut end;
(b) When repairing three types of oxide films: those with scratches on the surface and unetched cut edges and unformed parts, and (c) those where the film was intentionally damaged by further winding under the conditions of (b) above. This is a measurement of the flowing current. As a result, as shown in Figure 3, the leakage current is (a)
(curve a in the figure) reaches constant current fastest,
The one in (b) (curve b in the figure) is the next, and the one in (c) (curve c in the figure) is the slowest, and even when it reaches constant current, its value itself is higher than the others. ing. The above experiment shows that it is desirable to minimize the destruction of the oxide film of the electrode foil in order to reduce the leakage current.

Furthermore, it is well known that the leakage current changes greatly depending on the shock applied to the lead terminal after manufacture.

This invention was devised in view of the above points,
As shown in FIGS. 4 to 6, the etched first aluminum electrode plate 7 and the electrode plate 7
a first external terminal 8 connected to the electrode foil connecting portion 9; and a second external terminal 1 connected to the connecting portion 9.
An insulating case 11 is manufactured by embedding and molding 0 in resin, and a lid 11' is manufactured by embedding and molding a first aluminum electrode plate 7 and a first external terminal 8 connected to the electrode 7 in resin. , the above insulation case 1
1. Place the aluminum electrode plate 7 side of the lid 11' facing each other, and connect the part 13a of the etched and chemically formed second aluminum electrode foil 13 wrapped in the separator 12 such as impregnated electrolytic paper to the electrode foil connecting portion. 9, then connect the two insulation cases 1 mentioned above.
1. The lids 11' are stacked one on top of the other, and their outer peripheries are welded and sealed by ultrasonic welding, thermal welding, or the like.

Since the chip-type electrolytic capacitor of the present invention is constructed as described above, it is possible to freely select the shape such as a rectangular shape or a disk shape during molding, and the external terminals 8 and 10 can be freely positioned vertically and horizontally. Since the direction can be selected, it can be easily matched to the wiring direction of the board. Further, as shown in the internal wiring diagram of FIG. 6, the combination of electrolytic capacitors can be selected depending on the wiring on the board, so that functions can be diversified.

Furthermore, the thickness of the first aluminum electrode plate 7 and the second aluminum electrode foil 13 is not limited to the thickness of the foil or plate, and either side may be chemically treated to achieve the required function. Can be combined as required.

Note that in the above embodiment, a single-layer chip electrolytic capacitor can be constructed by removing the aluminum electrode plate 7 provided in the lid 11' and the first external terminal 8 connected to the electrode 7. Needless to say.

Chip-type electrolytic capacitors constructed as described above can have a relatively large capacitance because recent advances in aluminum foil etching technology have made it possible to increase the surface area. No winding in the process,
Since it does not damage the electrode foil, the leakage current is small, the shape can be freely designed such as rectangular or disc shape, it can correspond to the miniaturization of electronic equipment, and it can be automatically inserted into printed circuit boards. effective. Furthermore, the manufacturing cost of electrolytic capacitors can be significantly reduced as fewer parts are used.

As mentioned above, the present invention can greatly contribute to the technological development of electronic devices and has great industrial and practical value.

[Brief explanation of the drawing]

Figure 1 is a partially disassembled perspective view of a conventional electrolytic capacitor element, Figure 2 is a sectional view of a conventional electrolytic capacitor, Figure 3 is a leakage current-time characteristic diagram, and Figures 4 to 6 are a diagram of the current electrolytic capacitor element. An example of a chip type electrolytic capacitor, Fig. 4 is an exploded perspective view, Fig. 5 is a perspective view, and Fig. 6 is an exploded perspective view.
The figure is an internal wiring diagram. 7: First aluminum electrode plate, 8: First external terminal, 9: Electrode foil connection part, 10: Second external terminal, 11: Insulating case, 11' lid, 12: Separator, 13: Second Aluminum electrode foil.

Claims (1)

[Scope of utility model registration request] An insulating case made of resin in which a first aluminum electrode 7 in the form of a plate or foil, a first external terminal 8 connected to the electrode, and a second external terminal 10 having an electrode foil connection part 9 are embedded and molded. 11, a plate-shaped or foil-shaped second aluminum electrode 13 is laminated via a separator 12 impregnated with an electrolytic solution, and the second aluminum electrode 13 is connected to the electrode foil connecting portion 9 of the second external terminal. Connect to the insulation case 1 above.
A chip-type electrolytic capacitor is formed by fitting a lid 11' to 1 and sealing it.