JP3306200B2 - Manufacturing method of chip-shaped solid electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a chip-shaped solid electrolytic capacitor.

[0002]

2. Description of the Related Art Conventional chip-shaped solid electrolytic capacitors are:
As shown in FIG. 1, an anode lead wire 2 is attached to an anode element 1a of a porous sintered body, and a dielectric oxide film 3, a solid electrolyte 4, carbon 5 and a silver electrode layer 6 are sequentially formed on the surface of the anode element 1a. Thus, the outside of the capacitor element 1 is covered with an exterior resin 7 so that the anode lead wire 2 and the silver electrode layer 6 project at both ends, and then the anode lead wire protruding from the exterior resin 7 is formed. The anode metal layer 8 and the cathode metal layer 9 are provided on the surface of
And then immersed in the molten solder 10 to form anode and cathode solder metal layers.

[0003]

However, in the above-mentioned conventional chip-shaped solid electrolytic capacitor, when a part of the exterior resin 7 is removed by sandblasting or grinding in order to expose the periphery of the outer layer on the cathode side to the outside, Since the carbon 5 and the silver electrode layer 6 must be exposed while checking the exposed state of the cathode layer composed of the carbon 5 and the silver electrode layer 6, the work of the process is very difficult and the productivity is low. Had become. When the carbon 5 and the silver electrode layer 6 are broken, the leakage current of the capacitor,
There was a problem of increasing δ.

[0004] The present invention solves the above-mentioned conventional problems, is excellent in productivity and yield, and has a high leakage current,
It is an object of the present invention to provide a small chip solid electrolytic capacitor capable of obtaining a stable δ.

[0005]

In order to achieve the above object, a solid electrolytic capacitor chip according to the present invention has an anode lead wire 2 attached to an anode element 1a of a porous sintered body, and a dielectric wire is provided on the surface of the anode element 1a. A body oxide film 3, a solid electrolyte 4, and a cathode layer 11 (composed of carbon 5 and a silver electrode layer 6) are sequentially formed to form a capacitor element 1, and a bottom surface of the cathode layer opposed to a lead-out surface of an anode lead-out line 2 in the cathode layer. And a part of the periphery adjacent to the bottom surface, the carbon
And the silver electrode layer 6 are alternately coated, or a mixture of the carbon 5 and the silver electrode layer 6 is coated several layers and formed thicker than the cathode layer 11 on the side surface. An exterior resin 7 that covers the surface except for the tip of the anode lead wire 2 and a part of the cathode layer 11 that is formed thicker, and is formed on the surface of the anode lead wire of the exterior resin 7 and is connected to the anode lead wire 2 And a cathode terminal portion 9 formed on the exposed surface side of the cathode layer 11 of the exterior resin 7 and connected to a thicker portion of the cathode layer 11. is there.

[0006]

According to the above structure, since a part of the cathode layer 11 is formed to be thick, there is a case where a part of the exterior resin 7 is removed by sandblasting in order to expose the cathode layer 11 to the outside, or When a part of 7 is cut by slicing or removed by grinding with a grindstone or an abrasive, since a thick cathode layer 11 is present, strict work management of exposing the thin cathode layer so as not to be destroyed as in the conventional case is unnecessary. , And productivity is dramatically improved. In addition, since the cathode layer can be prevented from being damaged, it is possible to stabilize the electric characteristics of the leakage current and Tan δ.

Further, since the dielectric oxide film 3 is not damaged together with the cathode layer 11, an increase in leakage current and occurrence of a short circuit can be avoided, and the yield can be improved.

[0008]

Embodiment 1 An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 is a diagram showing the shape of a chip-shaped solid electrolytic capacitor according to an embodiment of the present invention.

In FIG. 2, reference numeral 1 denotes a capacitor element. The capacitor element 1 has an anode lead wire 2 attached to an anode element 1a made of a porous sintered body, and a dielectric oxide film 3 and a solid oxide film formed on the surface of the anode element 1a. The capacitor element 1 is formed by sequentially forming an electrolyte 4, carbon 5 and a silver electrode layer 6.

In the capacitor element 1, the cathode layer 11 composed of the carbon 5 and the silver electrode layer 6 is drawn out of the anode lead-out line 2 in the cathode layer 11, as shown in the sectional view of the embodiment of the cathode layer portion in FIG. Several layers of carbon 5 and silver electrode layer 6 are alternately applied to the bottom surface facing the surface and a part of the periphery adjacent to the bottom surface integrally with the cathode layer 11 so as to be higher than the portion of the cathode layer 11 located on the side surface. It is formed thick. The cathode layer 11 on the bottom surface is formed by sequentially applying and baking carbon 5 and silver electrode layer 6.

Next, an outer resin 7 is applied to the outer surface of the capacitor element 1 by an electrostatic coating method, or the capacitor element 1 is set in a mold, and the outer resin 7 is applied by a transfer molding method.

After the exterior, the exterior resin 7 together with the anode lead wire 2
Is cut off to expose the anode lead wire 2 from the exterior resin 7. The exposed anode lead wire 2 is subjected to sandblasting to roughen the surface. On the other hand, the cathode lead-out surface facing the anode lead-out line 2 is formed together with the exterior resin 7 together with the cathode layer 11.
Is cut off to obtain the standard dimensions of a chip-shaped solid electrolytic capacitor. At this time, since the thick cathode layer 11 is present, a strict operation of exposing the thin cathode layer 11 so as not to be destroyed when cutting by slice, grinding by sand blasting, or cutting with a grindstone or abrasive as in the conventional case. Management can be avoided and productivity can be significantly improved.

Further, damage to the cathode layer 11 and damage to the dielectric oxide film 3 can be avoided, and a leakage current and a stable Tan δ can be obtained.

Next, an anode terminal portion 8a is formed using a conductive silver paint, and at the same time, the roughened anode lead wire portion 2 is formed.
Also, a conductive silver paint is applied to form the anode terminal portion 8a. The cathode terminal 9a is coated with a conductive silver paint together with the exposed cathode layer 11 to form the cathode terminal 9a.

After baking and curing the conductive silver paint, the surfaces of the anode terminal portion 8a and the cathode terminal portion 9a are plated to form the anode metal layer 8 and the cathode metal layer 9, respectively. Finally, the entire capacitor element was immersed in the melted solder 10 and the anode lead wire 2 was cut at the end surface of the exterior resin to produce a chip-shaped solid electrolytic capacitor.

[0017]

Second Embodiment Next, another embodiment of the present invention will be described with reference to FIG. The basic manufacturing method is the same as that of the above-described embodiment, except for the method of forming the cathode portion 11 described below.

In the step of forming the cathode layer 11 of the first embodiment, the carbon 5 and the silver electrode are formed integrally with the cathode layer 11 on the bottom surface facing the lead-out surface of the anode lead wire 2 and a part of the periphery adjacent to the bottom surface. Instead of alternately applying several layers of layers 6, after coating and baking carbon 5, a mixture of carbon 5 and silver electrode layer 6 is applied several layers thicker than cathode layer 11 on the side surface to form a chip-shaped solid electrolytic capacitor. To manufacture.

[0019]

Embodiment 3 In another embodiment of the present invention, FIG. 5 shows an example in which the exterior is applied by a transfer molding method.

[0020]

As described above, the chip-shaped solid electrolytic capacitor of the present invention has a thicker part of the cathode layer, so that the cathode layer is exposed to the outside. When removing or removing part of the exterior resin by slicing or grinding with a grindstone or abrasive, there is a thick cathode layer, so strictly exposing so that the thin cathode layer is not destroyed as in the past Work management is not required, and productivity is dramatically improved. In addition, since the damage to the cathode layer can be avoided, it is possible to stabilize the electrical characteristics of the leakage current and Tan δ. In addition, since the dielectric oxide film is not damaged together with the cathode layer, an increase in leakage current and occurrence of a short circuit can be avoided, and the yield can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a conventional chip-shaped solid electrolytic capacitor.

FIG. 2 is an explanatory view of one embodiment of the chip-shaped solid electrolytic capacitor of the present invention.

FIG. 3 is a cross-sectional view showing one embodiment of a cathode layer portion in a manufacturing process of the chip-shaped solid electrolytic capacitor of the present invention.

FIG. 4 is a cross-sectional view showing another embodiment of the cathode layer portion in the process of manufacturing the chip-shaped solid electrolytic capacitor of the present invention.

FIG. 5 is a sectional view showing another embodiment of the chip-shaped solid electrolytic capacitor of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 capacitor element 1a anode element of porous sintered body 2 anode lead 3 dielectric oxide film 4 solid electrolyte 5 carbon 6 silver electrode (layer) 7 exterior resin 8 anode metal layer 8a anode terminal section 9 cathode metal layer 9a cathode Side terminal 10 Solder 11 Cathode layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01G 9/004 H01G 9/04 H01G 9/00

Claims (3)

(57) [Claims] An anode lead wire is attached to an anode body made of a valve metal, and a dielectric oxide film, an electrolyte layer,
Forming a capacitor element in which a cathode layer is sequentially formed, comprising an exterior resin covering the anode lead wire of the capacitor element so as to be drawn out, the cathode layer of the cathode part on the opposite side to the anode lead wire of the exterior resin is After forming a cathode layer thicker than the cathode layer on the side surface by a mixed layer composed of carbon and silver electrode layers on the bottom surface and the adjacent peripheral portion, the capacitor element including the cathode layer is covered with an exterior resin, and then the cathode layer is formed. And forming a cathode metal layer on a cathode lead-out surface on which at least a part of the cathode layer is exposed by removing part of the cathode layer. 2. The method of manufacturing a solid electrolytic capacitor according to claim 1, wherein the mixed layer is formed by alternately applying carbon and silver electrode layers in several layers on the bottom surface and the adjacent portion of the cathode portion. . 3. The method according to claim 1, wherein the mixed layer is formed by applying a mixture of carbon and silver electrodes.