JPS607473Y2 - solid electrolytic capacitor - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a solid electrolytic capacitor, particularly a chip type solid electrolytic capacitor.

Conventional chip-type solid electrolytic capacitors include those shown in FIGS. 1 and 2.

That is, as shown in FIG. 1, a lead wire 3 is connected to an anode lead wire 2 led out from a sintered capacitor element 1 made of a valve metal such as tantalum or aluminum so as to cross the anode lead wire 2 at right angles. However, the leading part of the anode lead wire 2 may be coated with a synthetic resin 4, or the lead plate 5 may be connected at right angles to the anode lead wire 2 as shown in FIG. There is also one in which the lead-out portion of the anode lead wire 2 is coated with a synthetic resin 6, similar to the above.

However, when a solid electrolytic capacitor with the above structure is connected to the anode and cathode electrodes formed on a substrate by soldering, etc., the lead wire 3 or the lead plate 5 may lift up from the electrode surface and a complete connection may not be possible. This was particularly noticeable when the capacitor element 1 was large in size.

This is due to the difference that occurs between the body surface of the capacitor element 1 and the lower surface of the lead wire 3 or lead plate 5.
In order to eliminate this difference, it is conceivable to make the lead wire 3 thicker or the lead plate 5 thicker, but this has the drawback that connection with the anode lead wire 2 becomes difficult.

Furthermore, welding is generally used as a means of connecting the lead wire 3 or lead plate 5 to the anode lead wire 2, but when connected by welding, it is very difficult for solder to adhere to the part where the welding tip contacts. In particular, in chip type solid electrolytic capacitors in which the lead wires 3 or lead plates 5 are small, there remains a problem in solderability.

Therefore, for example, the structure disclosed in FIG. 2 of Japanese Utility Model Application Publication No. 52-82045, that is, as shown in FIG.
The head 10 of the capacitor element 7 is welded to eliminate the level difference between the mounting surface 11 of the capacitor element 7 body surface to the board and the lower surface 12 of the Ω-shaped terminal 9 consisting of the mounting part to the board. The above-mentioned problem can be solved by making the attached parts different.

However, in the solid electrolytic capacitor constructed in this way, the anode lead wire 8 and the Ω-shaped terminal 9 are fixed only by welding, so external forces are applied to the welding point during the process, transportation, and mounting work to the board. In this case, there was a risk that the anode lead wire 8 and the Ω-shaped terminal 9 would separate, resulting in poor connection.

This invention was developed in view of the above points, and by improving the shape of the anode terminal to which the anode lead wire derived from the capacitor element is welded, the welding point and the surface to which the solder is attached to the board etc. are different, thereby solving the problem of solderability. This eliminates the need for stable soldering to the board, as well as locating the mounting surface of the cathode conductive layer of the capacitor element on the board and the soldering surface of the anode terminal on the same plane. The object of the present invention is to provide a solid electrolytic capacitor that completely eliminates the occurrence of connection failures due to external forces at the anode terminal.

This will be explained below using examples.

That is, as shown in FIGS. 4 and 5, the anode lead wire 2
An anodic oxide film 23. Manganese dioxide layer 2
4. A cathode conductive layer 26 is formed using solder or the like on the outer surface on which the semiconductor layer 25 and the like are sequentially formed, and a capacitor element 27 is formed.
Configure.

As shown in FIG. 6, the anode lead wire 21 is connected to a fitting through hole 28 into which the anode lead wire 21 is fitted, a vertical connecting portion 29 extending downward from the fitting through hole 28 and in surface contact with each other, and a vertical connecting portion 29 below the connecting portion 29. A flat mounting surface 30 with both ends extending horizontally in opposite directions.
are fitted into the fitting hole 28 of the anode terminal 31 formed integrally with the anode terminal 31, and the fitting portion is welded 32 to fix the anode lead wire 21 and the anode terminal 31, and the flat mounting surface 30 and The distance between the anode lead wires 21 is set to be approximately the same as the distance h1 between the anode lead wires 21 and a portion 33 which is the attachment surface of the cathode conductive layer 26 to the substrate constituting the surface of the capacitor element 27. be.

Note that 34 is a synthetic resin that covers the lead-out portion of the anode lead wire 21.

In the solid electrolytic capacitor having the above structure, as shown in FIG. 7, the flat mounting surfaces 30 of the cathode conductive layer 26 and anode terminal 31 constituting the capacitor element 27 are brought into contact with the electrodes 36 constituting the substrate 35, respectively, and soldered. The distance between the flat mounting surface 36 and the anode lead wire 21 and the mounting surface of the cathode conductive layer 26 constituting the surface of the capacitor element 27 to the substrate 35 are the same. Since the distance h1 between the anode terminal 31 and the anode lead wire 21 is approximately the same, connection such as soldering is easy and reliable, and 32 welding points between the anode terminal 31 and the anode lead wire 21 Since the soldering is done at a completely different location from the flat mounting surface 30 where the anode terminal 36 of the anode lead wire 21 is attached, the solderability is not hindered, and the anode terminal 31 of the anode lead wire 21
Since the welding 32 with the anode terminal 31 is fitted into the fitting hole 28 constituting the anode terminal 31, the risk of the welding 32 points peeling off due to various external forces and resulting in a poor connection can be completely eliminated, resulting in a stable connection. This provides superior effects that cannot be obtained from conventional techniques that can ensure the connection state.

In the above embodiment, the case where the cross-sectional shape of the capacitor element 27 is round has been described, but it goes without saying that the present invention can also be applied to a square or elliptical shape.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional solid electrolytic capacitor;
3 and 3 are perspective views showing other conventional examples of solid electrolytic capacitors, and FIGS. 4 and 5 show solid electrolytic capacitors according to an embodiment of the present invention. The figure is a front cross-sectional view, Figure 6 is a perspective view showing the anode terminal constituting the solid electrolytic capacitor of the present invention, and Figure 7 shows the solid electrolytic capacitor shown in Figures 4 and 5 attached to a board. FIG. 21...Anode lead wire, 26...Anode conductive layer, 27...Capacitor element, 28...
... Fitting hole, 29 ... Vertical connection part, 30 ...
...Flat mounting surface, 31... Anode terminal, 32
・・・・・・Welding, 33・・・・・・Position, h, hl
······distance.

Claims (2)

[Scope of utility model registration request] (1) A capacitor element 27 having a cathode conductive layer 26 formed on its outer surface, an anode lead wire 21 led out from the capacitor element 27, a fitting hole 28 into which the anode lead wire 21 is fitted, and the fitting through hole 28 An anode terminal 3 formed by integrally molding a vertical connecting portion 29 that extends downward and makes surface contact, and a flat mounting surface 30 that extends horizontally in opposite directions from both lower ends of the connecting portion 29.
1, the anode lead wire 21 and the fitting hole 28 are welded 32, and the distance between the flat mounting surface 30 and the anode lead wire 21 is set at a location that becomes the mounting surface of the cathode conductive layer 26. 33 and the anode lead wire 21 is approximately the same as the distance h1.
A solid electrolytic capacitor characterized by the following. (2) The cross-sectional shape of the capacitor element 27 is round, square,
The solid electrolytic capacitor according to claim (1) of the utility model registration, characterized in that it has an elliptical shape.