JPS6030117A - Leadframe for electrolytic condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lead frame for an electrolytic capacitor, and more particularly to a terminal member that is connected to an element lead of an electrolytic capacitor element and drawn out to the outside.

Since chip-type electrolytic capacitors are impregnated with an electrolyte, the metal that makes up the lead frame may undergo a chemical reaction with the electrolyte, causing corrosion. Therefore, the material of the lead frame is limited to metals that do not have such functions. Moreover, in electrolytic capacitors, the airtightness of the exterior member is related to moisture resistance and the like, and directly affects electrical performance, so adhesion to the exterior resin such as epoxy resin becomes a problem. Furthermore, if the linear expansion coefficients of the lead frame and the exterior resin differ greatly, thermal stress will occur, which will impede the airtightness of the exterior member over long periods of use.

An object of the present invention is to provide a lead frame for an electrolytic capacitor that has improved adhesion with an exterior member, has increased moisture resistance, and does not cause thermal stress with the exterior member.

This invention is characterized in that an aluminum layer is formed on the surface layer of the core material.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

1 and 2 show embodiments of the present invention, FIG. 1 shows the structure of a lead frame for an electrolytic capacitor, and FIG.
A cross section taken along line nn in the figure is shown. In the figure, the lead frame 2 has a plurality of pairs of lead parts 4A, 4 facing each other.
B is formed, and each lead portion 4A, 4B is supported by an arm portion 6 on both sides thereof. The through hole 8 is a space for inserting an electrolytic capacitor element. In addition, each lead part 4
A through hole 10 is formed in the tip portions of A and 4B in order to aid the flow of the exterior resin and improve adhesion to the exterior resin.

Each side of this lead frame 2 has a sprocket hole 1 that engages a sprocket for continuous transfer.
2.14 are formed at regular intervals.

As shown in FIG. 2, an aluminum layer 18 is uniformly formed on the surface of the core material 16 of this lead frame 2. As shown in FIG. In this example, aluminum J! 1B is heartwood 1
The surface of No. 6 is coated with aluminum foil. Such a rad treatment is performed on the surface of the core material 16 before molding the lead frame 2.

As shown in FIG. 3, the element leads 22A and 22B of the electrolytic capacitor element 20 are overlapped and welded to the surfaces of the lead parts 4A and 4B of the lead frame 2 processed in this way. Next, lead parts 4A and 4B from 1 lead frame 2.
It is cut out by pressing, etc., impregnated with electrolyte, and then covered with synthetic resin. The electrolytic solution may be injected through a small hole formed in the outer case member after forming the outer case with a synthetic resin.

FIG. 4 shows a chip type electrolytic capacitor using the lead frame 2. As shown in FIG. Immediately, the element leads 22A, 22
The electrolytic capacitor element 20 welded to B is sealed in the internal space 26 of a first exterior member 24 made of pps resin or the like, and the surface of this first exterior member 24 is made of epoxy resin or the like. A second exterior member 28 is formed.

And a welded part between the lead part 4A and the element lead 22A,
The welding part between the lead part 4B and the element 1" 22B is
The lead parts 4A and 4B embedded in the side walls of the first and second exterior members 24 and 28 and exposed from the side wall of the second exterior part JA28 are bent along the side walls, and their tips are It is arranged on the lower surface of the second exterior member 28.

If the lead frame 2 in which the aluminum layer 18 is formed on the surface layer of the core material 16 is used, the adhesion with the synthetic resin constituting the first and second exterior members 24 and 28 will be improved, and moisture resistance will be improved. can be improved. In particular, the linear expansion coefficient of such a lead frame 2 is
4.28, it has been experimentally confirmed that the thermal stress is small and the adhesion is high. Furthermore, even if it comes into contact with the electrolyte, since the surface layer is formed of the aluminum layer 18, problems such as corrosion will not occur. Furthermore, since the aluminum layer 18 is formed on the surface of the core material 16, various metal materials can be used, and materials with high strength and low cost, such as iron, can be freely selected.

Further, the lead portion 4A exposed from the second exterior member 28,
By plating the portion 4B with a metal that can be soldered, it can be face-bonded onto the conductor of the wiring board with solder.

As explained above, according to the present invention, it is possible to improve the adhesion with the synthetic resin of the exterior member, improve the moisture resistance, and prevent problems such as corrosion even if it comes into contact with the electrolyte, so that the electrolytic capacitor Reliability can be increased.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an embodiment of the lead frame for electrolytic capacitors of the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a frame to which an electrolytic capacitor element is attached. FIG. 4 is a plan view showing a chip type electrolytic capacitor embodying the present invention. 2... Lead frame, 4A, 4B... Lead part,
”6... Heartwood, 18... Aluminum layer.

Claims (1)

[Claims] A lead frame for electrolytic capacitors characterized by an aluminum layer formed on the surface layer of the core material.