JP2002299166A - Slid electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the volume ratio of a capacitor element to the occupied volume of a capacitor completed article, in a solid electrolytic capacitor where the capacitor element 14 is constituted by forming a dielectrics coating film layer 2, a solid state electrolyte layer 3 and a cathode lead-out layer 4 in order outside an anode member 1, where an anode lead pin 15 is implanted in one end, an anode terminal 5 is connected with the anode lead pin 15, a cathod terminal 6 is connected with the cathode lead-out layer 4, and the outside of the capacitor element is covered and sealed with a sheath resin layer. SOLUTION: The anode terminal and the cathode terminal have leg parts 51, 52 composed of metal plates which are so bent that the sections are almost L-shaped; in the anode terminal, one end of the L-shaped leg part is further bent outwardly of the L-shape and welded to the anode lead pin; the inner surface of the L-shaped leg part is brought into close contact with the sheath resin layer; and in the cathode terminal, an inner surface of the L-shaped leg part is brazed to the cathode lead-out layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a chip-type solid electrolytic capacitor suitable for surface mounting on a printed wiring board or the like.

[0002]

2. Description of the Related Art As a chip type solid electrolytic capacitor suitable for surface mounting on a printed wiring board or the like, one having a configuration as shown in FIG. 9 is known.

In this solid electrolytic capacitor, a dielectric film layer 2 having a surface of the anode member electrolytically oxidized is provided outside an anode member 1 made of a sintered body of a valve metal (tantalum, niobium, titanium, aluminum, etc.). , Manganese dioxide, TCN
A capacitor element 14 was formed by sequentially forming a solid electrolyte layer 3 made of a Q complex salt, a conductive polymer, and the like, and a cathode extraction layer 4 made of a conductive carbon, silver, and the like. The anode terminal 50 is welded to the anode lead pin 15, the cathode terminal 60 is soldered to the cathode lead layer 4, and the outside of the capacitor element 14 is covered and sealed with an exterior resin layer 7 made of epoxy resin or the like.

One end of each of the anode terminal and the cathode terminal is connected to the anode lead pin and the cathode lead layer as described above, and the other end is pulled out to the outside through the package resin layer. And is provided for surface mounting on a printed wiring board or the like.

[0005]

In the solid electrolytic capacitor according to the prior art described above, in order to bend the anode terminal and the cathode terminal when they are pulled out of the exterior resin layer, it is necessary to penetrate the exterior resin layer through the anode terminal and the cathode terminal. It is necessary to take a bending allowance, and the thickness of the exterior resin layer along that direction becomes larger by the bending allowance than at other locations.
For example, in the case of a chip type capacitor having an outer size of L (length) 7.3 mm and W (width) 4.3 mm (hereinafter, referred to as D size), an exterior resin layer in the anode terminal penetrating portion and the cathode terminal penetrating portion. Is about 1.8m each
m, about 1.5 mm.

In the configuration in which the anode terminal and the cathode terminal are bent along the outer periphery of the exterior resin layer, the outer size of the exterior resin layer is equal to the thickness of the anode terminal and the cathode terminal with respect to the external size of the completed capacitor. It is necessary to reduce the size. For example, the external dimensions (L
7.3 mm), the size of the exterior resin layer in the L direction was about 7.1 mm.

Thus, in the solid electrolytic capacitor according to the prior art described above, the volume ratio of the capacitor element to the occupied volume of the finished capacitor is considerably reduced. For example, when the D size is H (height) 2.8 mm. The volume ratio was about 34% as shown in Table 1.

[0008]

[Table 1]

The present invention has been made in view of the above-mentioned problems of the prior art, and provides a small and large-capacity chip-type solid electrolytic capacitor by improving the volume ratio of a capacitor element to the occupied volume of a completed capacitor. It is.

[0010]

A solid electrolytic capacitor according to the present invention comprises a capacitor element having a dielectric film layer, a solid electrolyte layer and a cathode lead layer formed sequentially on the outside of an anode member having an anode lead pin planted at one end. In the solid electrolytic capacitor in which an anode terminal is connected to the anode lead pin, a cathode terminal is connected to the cathode extraction layer, and the outside of the capacitor element is covered and sealed with an exterior resin layer, the anode terminal and the cathode terminal Has a leg made of a metal plate bent into a substantially L-shaped cross section, and the anode terminal is further bent at one end of the L-shaped leg toward the outside of the L-shape and welded to the anode lead pin. In addition, the inside surface of the L-shaped leg is in close contact with the exterior resin layer, and the cathode terminal is characterized in that the inside surface of the L-shaped leg is brazed to the cathode extraction layer. It is an.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A solid electrolytic capacitor according to an embodiment of the present invention is shown in FIGS.
(A-A cross-sectional view).

This solid electrolytic capacitor has a dielectric coating layer 2 having a surface of the anode member electrolytically oxidized on the outside of an anode member 1 made of a sintered body of a valve action metal (tantalum, niobium, titanium, aluminum, etc.). , Manganese dioxide, TCN
A solid electrolyte layer 3 made of a Q complex salt, a conductive polymer or the like, and a cathode extraction layer 4 made of a conductive carbon, silver or the like are sequentially formed to form a capacitor element 14, which is set on one end surface of the anode member 1. Connect the anode terminal 5 to the anode lead pin 15,
A solid electrolytic capacitor in which a cathode terminal 6 is connected to the cathode extraction layer 4 and the outside of the capacitor element 14 is covered and sealed with an exterior resin layer 7 made of epoxy resin or the like, wherein the anode terminal 5 and the cathode terminal 6 are The anode terminal 5 has one end 52 of the L-shaped leg 51 further bent toward the outside of the L-shape. The anode lead pin 1
5, the inner surface of the L-shaped leg 51 is in close contact with the exterior resin layer, and a solder coating layer 53 is formed on the outer surface of the L-shaped leg 51. L
The inner surface of the L-shaped leg 61 is soldered to the cathode extraction layer 4 by a conductive adhesive 46 containing silver or the like, and a solder coating layer 63 is formed on the outer surface of the L-shaped leg 61.

The manganese dioxide layer as the solid electrolyte layer 3 is formed by a method such as thermal decomposition of manganese nitrate.
The CNQ complex salt layer is formed by a melt impregnation method of the TCNQ complex salt, and the conductive polymer layer is formed of pyrrole, thiophene,
It is formed by chemical oxidation polymerization or electrolytic oxidation polymerization of aniline or a derivative thereof.

The cathode extraction layer 4 comprises the solid electrolyte layer 3
A layer containing conductive carbon by applying conductive carbon dissolved in an organic solvent on the outside of the layer and drying it, and further applying silver (a so-called silver paste) dissolved in an organic solvent on the outside and drying the layer. And a layer containing silver are sequentially laminated.

A process for forming the exterior resin layer 7 after connecting the anode terminal 5 and the cathode terminal 6 to the capacitor element 14 will be described below.

First, a 42 alloy plate having a thickness of about 0.1 mm is subjected to Ni plating and solder plating, and is formed into a shape as shown in FIG. 3 (one end of a substantially L-shaped cross section is further bent toward the outside of the L shape. The anode terminal member 55
And a cathode terminal member 66 is prepared.

Next, as shown in FIG. 4, the anode lead pin 15 pulled out of the capacitor element 14 is connected to a portion 52 of one end of the L-shaped leg 51 of the anode terminal member, which is bent toward the outside of the L-shape. To the inner surface 61a of the L-shaped leg 61 of the cathode terminal member with the capacitor element 14
Is soldered to a cathode extraction layer (not shown), which is the outermost layer, by a conductive adhesive 46 containing silver. At this time, if a plurality of capacitor elements are arranged at equal intervals and connected to the pair of anode terminal members and cathode terminal members (specifically, the anode lead pins are welded to the points indicated by points P1 to P3 in FIG. 3). And
If this block is used as a processing unit), mass productivity is improved.

Next, as shown in FIG. 5, above the inside of the L-shaped legs 51, 61 of the anode terminal member and the cathode terminal member,
An exterior resin layer 7 made of epoxy resin or the like is molded in a space including the capacitor element 14. As a molding method, an injection molding method such as a transfer molding method and an injection molding method can be used. At this time, if the processing is performed in units of blocks in which a plurality of capacitor elements are arranged as described above, the appearance is as shown in FIG.

Next, after the burrs of the exterior resin layer are removed by honing, as shown in FIG. 7, the outer surfaces 51 of the L-shaped legs 51, 61 of the anode terminal member and the cathode terminal member.
a and 51b are coated with solder coating layers 53 and 63, respectively.

Finally, if unnecessary portions of the anode terminal member and the cathode terminal member are cut and processed in units of blocks in which a plurality of capacitor elements are arranged as described above, a capacitor block as shown in FIG. -B1 and B2-B2
The solid electrolytic capacitor as shown in FIGS. 1 and 2 is completed.

In the solid electrolytic capacitor according to the embodiment of the present invention, since it is not necessary to bend the anode terminal and the cathode terminal after forming the exterior resin layer as in the prior art, at least the exterior resin layer on the cathode terminal side is not required. The thickness can be reduced by about 0.9 mm.

Further, since it is not necessary to bend the anode terminal and the cathode terminal along the outer periphery of the exterior resin layer, the size of the exterior resin layer in the L direction can be made smaller than the conventional case by the thickness of the anode terminal and the cathode terminal (about 0). .1 mm × 2).

Thus, assuming that the external size of the completed capacitor is constant, the length of the capacitor element is about 1.1 m.
m. Table 2 summarizes these dimensional relationships.

[0024]

[Table 2]

In the height direction of the capacitor, the conductive adhesive 46 (about 0.1 mm thick) and the cathode terminal 60 (thickness) are conventionally provided above the capacitor element 14 as shown in FIG. However, in the embodiment of the present invention, these layers become unnecessary, and the capacitor element can be made higher accordingly. Table 3 summarizes these dimensional relationships.

[0026]

[Table 3]

The relationship between the width of the completed capacitor and the width of the capacitor element in the embodiment of the present invention is the same as that of the conventional example.

Thus, in the solid electrolytic capacitor according to the embodiment of the present invention, the volume ratio of the capacitor element to the occupied volume of the completed capacitor product can be increased to about 48% as shown in Table 4.

[0029]

[Table 4]

[0030]

According to the present invention, one end of the L-shaped leg of the anode terminal is further bent toward the outside of the L-shape and welded to the anode lead pin, and the inner surface of the L-shaped leg of the anode terminal is exteriorized. The inner surface of the L-shaped leg portion of the cathode terminal is soldered to the cathode lead layer of the capacitor element by bringing the outer surface of the outer resin layer in the length direction and the height direction of the finished capacitor into close contact with the resin layer. Can be made thinner than before, and as a result, the volume ratio of the capacitor element to the occupied volume of the finished capacitor product can be increased, thereby providing a small, large-capacity chip-type solid electrolytic capacitor. it can. (2) Since it is not necessary to bend the anode terminal and the cathode terminal after forming the exterior resin layer, the number of working steps is reduced. (3) Compared to the conventional configuration in which one end of the cathode terminal is soldered to the cathode extraction layer of the capacitor element and the other is routed along the outer periphery of the exterior resin layer, the effective resistance component and inductance component of the cathode terminal portion are reduced. And ESR (equivalent series resistance) and ESL (equivalent series inductance) of the completed capacitor can be reduced.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 3 is an external perspective view of an anode terminal member and a cathode terminal member used in the embodiment of the present invention.

FIG. 4 is a sectional view of a capacitor element and the like for describing a method of manufacturing a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 5 is a sectional view of a capacitor element and the like for describing a method of manufacturing a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 6 is an external perspective view of a capacitor block for explaining a method of manufacturing a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 7 is a sectional view of a capacitor element and the like for describing a method of manufacturing a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 8 is an external perspective view of a capacitor block for describing a method of manufacturing a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 9 is a sectional view of a conventional solid electrolytic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode member 14 Capacitor element 15 Anode lead pin 2 Dielectric film layer 3 Solid electrolyte layer 4 Cathode extraction layer 46 Conductive adhesive material 5 Anode terminal 51 Leg of anode terminal 53 Solder coating layer of anode terminal 6 Negative terminal 61 Negative terminal Leg 63 Solder coating layer of cathode terminal 7 Exterior resin layer

Claims (2)

[Claims] 1. A capacitor element is formed by sequentially forming a dielectric film layer, a solid electrolyte layer, and a cathode extraction layer on the outside of an anode member having an anode lead pin implanted at one end, and an anode terminal is connected to the anode lead pin. In a solid electrolytic capacitor in which a cathode terminal is connected to the cathode extraction layer and the outside of the capacitor element is covered and sealed with an exterior resin layer, the anode terminal and the cathode terminal are each formed by bending a metal plate having a substantially L-shaped cross section. The anode terminal further includes an L-shaped leg having one end bent outward toward the L-shape and welded to the anode lead pin, and an inner surface of the L-shaped leg. A solid electrolytic capacitor, wherein the inner surface of the L-shaped leg portion of the cathode terminal is soldered to the cathode extraction layer. 2. The solid electrolytic capacitor according to claim 1, wherein the anode terminal and the cathode terminal have a solder coating layer formed on an outer surface of the L-shaped leg.