JPH1126303A - Solid electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid electrolytic capacitor wherein the stability in resistance characteristic is excellent. SOLUTION: This capacitor comprises a capacitor element 11 (wherein a dielectric oxide film, a solid electrolytic layer, a cathode layer 13 are formed in this order on the surface of an anode body which comprises a valve-action metal embedded with an anode lead-out line, so that its one end part is exposed), an internal anode terminal 15 connected to one end part of an anode lead-out line 12, an internal cathode terminal 17 connected to the surface of a cathode layer 13 via a conductive bonding agent 18, a high airtight material 20 which coats the anode lead-out line 12 side of the capacitor element 11, outer housing resin 21 which coats a highly airtight material 19, the abode lead-out line 12, the internal anode terminal 15, and the internal cathode terminal 17 so that a part of the internal cathode terminal 17 and a part of the internal anode terminal 15 are exposed outside, and an external anode terminal 16 and external cathode terminal 19 connected to the part of the internal anode terminal 15 the part of the internal cathode terminal 17 which are exposed outside of the armor resin 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolytic capacitor used for various electronic devices.

[0002]

2. Description of the Related Art A conventional solid electrolytic capacitor of this type is:
The configuration was as shown in FIG. That is, in FIG. 6, reference numeral 1 denotes a capacitor element, and this capacitor element 1 derives an anode lead wire 2 made of a valve action metal from a porous anode body formed by molding and sintering a valve action metal powder. A dielectric oxide film is formed by anodic oxidation on a part of the porous anode body and a surface of the porous anode body, and a solid electrolyte layer made of manganese dioxide, an organic semiconductor, a conductive polymer, or the like is formed on the surface of the dielectric oxide film. Is formed, and a cathode layer 3 is formed on the surface thereof. In addition,
The cathode layer 3 is formed by sequentially laminating a carbon layer and a silver paint layer by an immersion method.

[0003] Reference numeral 4 denotes an insulating plate mounted on the anode lead wire 2. Reference numeral 5 denotes an anode terminal. One end of the anode terminal 5 is connected to the anode lead wire 2 by welding, and the other end is bent along the side and bottom surfaces of the exterior resin after molding the exterior resin described later. Reference numeral 6 denotes a cathode terminal.
One end is connected to the cathode layer 3 of the capacitor element 1 by a conductive adhesive 7, and the other end is bent along the side and bottom surfaces of the exterior resin after molding of the exterior resin described later. Reference numeral 8 denotes an exterior resin made of an epoxy resin that covers the entire capacitor element 1 by molding.

[0004]

However, in the solid electrolytic capacitor shown in FIG. 6, when a heat resistance test such as solder heat resistance is carried out, the capacitor is formed by molding the above-mentioned anode lead wire 2, anode terminal 5, cathode terminal 6 by molding. Water vapor and oxygen in the atmosphere gradually enter into the inside of the capacitor element 1 from a small gap formed in a contact portion with an exterior resin 8 made of epoxy resin which covers the entire element 1, whereby the solid electrolyte layer And / or the interface between the solid electrolyte layer and the cathode layer is deteriorated, and the resistance characteristics are significantly impaired.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a solid electrolytic capacitor having extremely excellent stability of resistance characteristics.

[0006]

In order to achieve the above object, a solid electrolytic capacitor according to the present invention comprises an anode body made of a valve action metal having an anode lead wire embedded so that one end of the anode lead wire is exposed. A capacitor element formed by sequentially forming a dielectric oxide film, a solid electrolyte layer, and a cathode layer on the surface, an internal anode terminal connected to one end of an anode lead wire in the capacitor element, and a cathode layer in the capacitor element An internal cathode terminal connected to the surface by a conductive adhesive,
A highly airtight material covering the anode lead wire side of the capacitor element, and the high airtight material, the anode lead wire, and the inside so that a part of the internal anode terminal and a part of the internal cathode terminal are exposed to the outside; An anode terminal, an exterior resin covering the internal cathode terminal, and an external anode terminal and an external cathode terminal connected to a part of the internal anode terminal and a part of the internal cathode terminal exposed to the outside from the exterior resin. According to this configuration, it is possible to obtain a solid electrolytic capacitor having extremely excellent stability of resistance characteristics.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a method in which a dielectric oxide is formed on the surface of an anode body made of a valve metal in which an anode lead wire is embedded so that one end of the anode lead wire is exposed. A capacitor element formed by sequentially forming a film, a solid electrolyte layer, and a cathode layer; an internal anode terminal connected to one end of an anode lead wire in the capacitor element; and a conductive adhesive on the surface of the cathode layer in the capacitor element. An internal cathode terminal connected by an agent, a highly airtight material covering the anode lead-out line side of the capacitor element, and a portion of the internal anode terminal and a portion of the internal cathode terminal are exposed so as to be exposed to the outside. A highly airtight material, an outer lead wire, an outer resin covering the inner anode terminal and the inner cathode terminal, and a part of the inner anode terminal and a part of the inner cathode terminal exposed to the outside from the outer resin. anode According to this configuration, an internal cathode terminal connected to the surface of the cathode layer of the capacitor element by a conductive adhesive, and an exterior resin covering the internal cathode terminal and the like are provided. The external cathode terminal connected to a part of the internal cathode terminal exposed to the outside covers the surface other than the anode lead-out surface from which the anode lead-out line of the capacitor element is led out. Since the invasion of water vapor and oxygen from the surface of the capacitor element can be reliably prevented, and the anode lead wire side of the capacitor element is reliably covered with a highly airtight material,
When a heat resistance test such as solder heat resistance is performed, even if there is a slight gap between the anode lead wire, the internal anode terminal, and the contact portion between the internal cathode terminal and the exterior resin, the presence of a highly airtight material will prevent The water vapor and oxygen therein do not directly enter the inside of the capacitor element, so that the solid electrolyte layer and / or the interface between the solid electrolyte layer and the cathode layer constituting the capacitor element do not deteriorate. It is possible to easily obtain a solid electrolytic capacitor having extremely excellent stability of resistance characteristics.

According to a second aspect of the present invention, a dielectric oxide film and a conductive polymer are provided on the surface of an anode body made of a valve metal in which an anode lead wire is embedded so that one end of the anode lead wire is exposed. A capacitor element formed by sequentially forming a solid electrolyte layer and a cathode layer, an internal anode terminal connected to one end of an anode lead-out line in the capacitor element, and an anode of the capacitor element on the surface of the cathode layer in the capacitor element. An internal cathode terminal connected by a conductive adhesive so as to cover a surface other than the anode lead-out surface from which the lead-out line is led out, and a highly airtight material covering the anode lead-out line side of the capacitor element,
The highly airtight material, the anode lead wire, the internal anode terminal, an exterior resin covering the internal cathode terminal so that a part of the internal anode terminal and a part of the internal cathode terminal are exposed to the outside, and With an external anode terminal and an external cathode terminal connected to a part of the internal anode terminal and a part of the internal cathode terminal exposed to the outside, according to this configuration, the surface of the cathode layer in the capacitor element is provided. The anode of the capacitor element is led out by an internal cathode terminal connected by a conductive adhesive and an external cathode terminal connected to a part of the internal cathode terminal exposed to the outside from an exterior resin covering the internal cathode terminal and the like. Since the wire covers the surface other than the anode lead-out surface from which the wire is led out, it is possible to reliably prevent intrusion of water vapor and oxygen from the surface other than the anode lead-out surface of the capacitor element, and to prevent the capacitor element from entering. Since the lead wire side is securely covered with a highly airtight material, when conducting a heat resistance test such as soldering heat resistance, the contact between the anode lead wire, internal anode terminal, internal cathode terminal and the exterior resin may be slightly Even if there is a large gap, due to the presence of the highly airtight material, the oxygen in the atmosphere does not directly enter the inside of the capacitor element, and as a result, the capacitor element is composed of the conductive polymer. Since the solid electrolyte layer does not cause oxygen deterioration, it is possible to easily obtain a solid electrolytic capacitor having extremely excellent stability of resistance characteristics.

Next, specific embodiments 1, 2 and 2 of the present invention will be described.
3, 4 and 5 and Conventional Examples 1 and 2 will be described with reference to the accompanying drawings.

(Embodiment 1) FIG. 1 is a sectional view of a conductive polymer tantalum solid electrolytic capacitor according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 11 denotes a capacitor element; The element 11 has a porous anode obtained by embedding the anode lead wire 12 so that one end of the anode lead wire 12 made of a tantalum wire is exposed, and molding and sintering tantalum metal powder as a valve metal. A dielectric oxide film is formed on the surface of the body and a part of the anode lead wire 12 by anodic oxidation, and a solid electrolyte layer made of a conductive polymer, polypyrrole, is formed on this surface. The cathode layer 13 is formed by sequentially stacking layers.

Reference numeral 14 denotes an insulating plate mounted on the anode lead wire 12. Reference numeral 15 denotes an internal anode terminal. One end of the internal anode terminal 15 is connected to one end of the anode lead wire 12 by welding, and the other end is formed by molding an exterior resin, which will be described later, and the side and upper and lower surfaces of the exterior resin. Is connected to the external anode terminal 16 which covers

Reference numeral 17 denotes an internal cathode terminal. The internal cathode terminal 17 is provided on the surface of the cathode layer 13 of the capacitor element 11 on the anode lead surface and the anode lead line 12 from which the anode lead wire 12 of the capacitor element 11 is led. Are connected by a conductive adhesive 18 so as to cover surfaces other than the surface located on the opposite side. Reference numeral 19 denotes an external cathode terminal. The external cathode terminal 19 is formed of a conductive adhesive 18 located on the side opposite to the anode lead-out line 12 and an outer surface of the internal cathode terminal 17 located on the side opposite to the anode lead-out line 12. It is provided so as to cover the part.

Reference numeral 20 denotes a highly airtight material comprising alkyl and / or alkylene obtained by applying a 30% solution of polyisobutylene in n-hexane (viscosity 0.03 Pa · s) with a dispenser and drying. The airtight material 20 covers the anode lead-out surface of the capacitor element 11, the cathode layer 13, a part of the internal cathode terminal 17, a part of the conductive adhesive 18, and a part of the anode lead-out wire 12. Is provided on the side of the anode lead-out line 12. And this highly airtight material 20
Since the adhesiveness to the capacitor element 11 is excellent, the electrical resistance is high, and the intrusion of atmospheric oxygen into the interior of the capacitor element 11 can be reliably prevented, so that good capacitor characteristics can be obtained. You can do it.

Reference numeral 21 denotes the highly airtight material 20, the anode lead-out line 12, a part of the internal anode terminal 15, and an internal part so that a part of the internal anode terminal 15 and a part of the internal cathode terminal 17 are exposed to the outside. The exterior resin 21 covers a part of the cathode terminal 17, and the exterior resin 21 is formed by molding with epoxy resin.

(Embodiment 2) FIG. 2 is a sectional view of a conductive polymer tantalum solid electrolytic capacitor according to an embodiment of the present invention. The internal cathode terminal 17a is connected to the surface by a conductive adhesive 18 so as to cover a surface other than the anode lead-out surface from which the anode lead-out wire 12 of the capacitor element 11 is led out, and the external cathode terminal 19a is connected to the internal cathode terminal 17a. It was provided only on a part of the surface adjacent to the surface located on the side opposite to the anode lead-out wire 12, and the other configuration was the same as that of the first embodiment.

(Embodiment 3) FIG. 3 is a sectional view of a conductive polymer tantalum solid electrolytic capacitor according to an embodiment of the present invention. The internal cathode terminal 17b is connected to the surface by a conductive adhesive 18 so as to cover a surface other than the anode lead-out surface from which the anode lead-out line 12 of the capacitor element 11 is led out, and the external cathode terminal 19b is connected to the internal cathode terminal 17b. It was provided so as to cover a surface located on the side opposite to the anode lead-out line 12 and a part of a surface adjacent to this surface, and the other configuration was the same as that of the first embodiment.

(Embodiment 4) FIG. 4 is a sectional view of a conductive polymer tantalum solid electrolytic capacitor according to Embodiment 4 of the present invention. The internal cathode terminal 17c and the external cathode terminal 19c integrated so as to cover the surface other than the anode lead-out surface from which the anode lead-out wire 12 of the capacitor element 11 is led out with the conductive adhesive 18 The other configuration is the same as that of the first embodiment.

(Embodiment 5) FIG. 5 is a sectional view of a tantalum solid electrolytic capacitor according to Embodiment 5 of the present invention. A solid electrolyte layer made of a certain polypyrrole was replaced with a solid electrolyte layer made of manganese dioxide, and the other structure was the same as that of the fourth embodiment.

(Conventional Example 1) FIG. 6 is a cross-sectional view of a conventional tantalum solid electrolytic capacitor using a solid electrolyte made of a conductive polymer.
Is a capacitor element. This capacitor element 1 is formed by embedding the anode lead wire 2 so that one end of the anode lead wire 2 made of a tantalum wire is exposed, and molding and sintering a tantalum metal powder as a valve action metal. A dielectric oxide film is formed by anodic oxidation on the surface of the obtained porous anode body and a part of the anode lead wire 2, and a solid electrolyte layer made of conductive polymer polypyrrole is formed on this surface, afterwards,
The cathode layer 3 composed of a carbon layer and a silver paint layer is sequentially laminated.

Reference numeral 4 denotes an insulating plate mounted on the anode lead wire 2. Reference numeral 5 denotes an anode terminal. One end of the anode terminal 5 is connected to one end of the anode lead wire 2 by welding, and the other end is formed along the side and bottom surfaces of the exterior resin after molding of an exterior resin described later. Bendable. Reference numeral 6 denotes a cathode terminal. One end of the cathode terminal 6 is connected to the cathode layer 3 of the capacitor element 1 by a conductive adhesive 7, and the other end thereof is formed by molding an exterior resin described later, and the side of the exterior resin and Folds along the bottom. Reference numeral 8 denotes the conductive adhesive 7, the anode lead wire 2, a part of the anode terminal 5, and a part of the cathode terminal 6 so that a part of the anode terminal 5 and a part of the cathode terminal 6 are exposed to the outside. This is an exterior resin to be covered, and the exterior resin 8 is formed by molding with an epoxy resin.

(Conventional Example 2) Conventional Example 1 is the same as Conventional Example 1 except that the solid electrolyte layer composed of polypyrrole, which is a conductive polymer, is replaced with a solid electrolyte layer composed of manganese dioxide.
The configuration was the same as described above.

Table 1 shows Embodiments 1, 2, and 2 of the present invention.
The results obtained by subjecting the tantalum solid electrolytic capacitors of 3, 4, 5 and Conventional Examples 1 and 2 to a solder heat resistance test at 260 ° C. for 10 seconds and then performing a high-temperature no-load test in an oxygen atmosphere at 125 ° C. It is a thing.

[0023]

[Table 1]

As is clear from Table 1, the tantalum solid electrolytic capacitors according to the first, second, third, fourth and fifth embodiments of the present invention have an atmosphere inside the capacitor element 11 even after the soldering heat test. Since there is no intrusion of oxygen inside, the change in resistance characteristics when a high-temperature no-load test is performed in an oxygen atmosphere at 125 ° C. is extremely small, and the stability of the resistance characteristics is also excellent. Solid electrolytic capacitor can be obtained. On the other hand, the tantalum solid electrolytic capacitor using the solid electrolyte made of the conductive polymer of Conventional Example 1 shown in FIG.
FIG. 6 shows the results of a high-temperature no-load test performed in an oxygen
Oxygen in the atmosphere gradually penetrates into the capacitor element 1 through a small gap formed in the contact portion between the anode lead wire 2, the anode terminal 5, the cathode terminal 6, and the exterior resin 8 shown in FIG. As a result, the solid electrolyte layer made of a conductive polymer causes oxygen deterioration, so that the resistance characteristics are significantly impaired.

Table 2 shows Embodiments 1, 2 and 2 of the present invention.
The tantalum solid electrolytic capacitors of 3, 4, 5 and Conventional Examples 1 and 2 were subjected to a soldering heat test at 260 ° C. for 10 seconds, and then in a steam atmosphere at 85 ° C. and a relative humidity of 90 to 95%. It shows the result of conducting a moisture resistance no-load test.

[0026]

[Table 2]

As is clear from Table 2, the tantalum solid electrolytic capacitors according to the first, second, third, fourth and fifth embodiments of the present invention have a high resistance to the inside of the capacitor element 11 even after the solder heat resistance test. Since the intrusion of water vapor in the atmosphere can be suppressed, the change in resistance characteristics when a moisture resistance and no-load test is performed in a water vapor atmosphere is extremely small, and the stability of the resistance characteristics is also excellent. The solid electrolytic capacitor described above can be obtained.

On the other hand, the tantalum solid electrolytic capacitor of the prior art example 2 shown in FIG. 6 has the anode lead wire 2, anode terminal 5, and cathode terminal 6 shown in FIG. And water vapor in the atmosphere gradually penetrates into the inside of the capacitor element 1 from a small gap formed in a contact portion with the exterior resin 8, whereby the solid electrolyte layer and / or the solid electrolyte layer and the cathode layer Since the interface causes deterioration, the resistance characteristics are significantly impaired.

The first, second and third embodiments of the present invention are described.
In 3, 4, and 5, a description has been given of the case where the anode element constituting the capacitor element 11 is formed by molding and sintering a tantalum metal powder as a valve action metal, but other valves such as aluminum and titanium are used. The anode body may be formed using a working metal. In the first, second, third, fourth, and fifth embodiments of the present invention, the solid electrolyte layer is made of polypyrrole or manganese dioxide, which is a conductive polymer.
The solid electrolyte layer may be formed using polythiophene, polyaniline, or the like.

[0030]

As described above, in the solid electrolytic capacitor of the present invention, a dielectric oxide film is formed on the surface of an anode body made of a valve metal in which an anode lead wire is embedded so that one end of the anode lead wire is exposed. A capacitor element formed by sequentially forming a solid electrolyte layer and a cathode layer; an internal anode terminal connected to one end of an anode lead wire of the capacitor element; and an anode lead of the capacitor element on the surface of the cathode layer of the capacitor element. An internal cathode terminal connected by a conductive adhesive so as to cover a surface other than the anode lead-out surface from which the wire is led out, and a highly airtight material covering the anode lead-out line side of the capacitor element,
The highly airtight material, the anode lead wire, the internal anode terminal, an exterior resin covering the internal cathode terminal so that a part of the internal anode terminal and a part of the internal cathode terminal are exposed to the outside, and With an external anode terminal and an external cathode terminal connected to a part of the internal anode terminal and a part of the internal cathode terminal exposed to the outside, according to this configuration, the surface of the cathode layer in the capacitor element is provided. The anode of the capacitor element is led out by an internal cathode terminal connected by a conductive adhesive and an external cathode terminal connected to a part of the internal cathode terminal exposed to the outside from an exterior resin covering the internal cathode terminal and the like. Since the wire covers the surface other than the anode lead-out surface from which the wire is led out, it is possible to reliably prevent intrusion of water vapor and oxygen from the surface other than the anode lead-out surface of the capacitor element, and to prevent the capacitor element from entering. Since the lead wire side is securely coated with a highly airtight material, when conducting a heat resistance test such as soldering heat resistance, only a small part of the anode lead wire, internal anode terminal, and the contact portion between the internal cathode terminal and the exterior resin are exposed. Even if there is a gap, the presence of the highly airtight material prevents water vapor and oxygen in the atmosphere from directly entering the inside of the capacitor element. As a result, the solid electrolyte layer and the Since the deterioration of the interface between the solid electrolyte layer and the cathode layer does not occur, it is possible to easily obtain a solid electrolytic capacitor having extremely excellent stability of resistance characteristics.

[Brief description of the drawings]

FIG. 1 is a sectional view of a conductive polymer tantalum solid electrolytic capacitor showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conductive polymer tantalum solid electrolytic capacitor according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a conductive polymer tantalum solid electrolytic capacitor showing a third embodiment of the present invention.

FIG. 4 is a sectional view of a conductive polymer tantalum solid electrolytic capacitor showing a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a tantalum solid electrolytic capacitor showing a fifth embodiment of the present invention.

FIG. 6 is a sectional view showing a conventional tantalum solid electrolytic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Capacitor element 12 Anode lead-out line 13 Cathode layer 15 Internal anode terminal 16 External anode terminal 17, 17a, 17b, 17c Internal cathode terminal 18 Conductive adhesive 19, 19a, 19b, 19c External cathode terminal 20 High airtight material 21 Exterior resin

Claims (2)

[Claims] 1. A structure in which a dielectric oxide film, a solid electrolyte layer, and a cathode layer are sequentially formed on the surface of an anode body made of a valve metal in which an anode lead wire is embedded so that one end of the anode lead wire is exposed. A capacitor element, an internal anode terminal connected to one end of an anode lead wire in the capacitor element, an internal cathode terminal connected to the surface of the cathode layer in the capacitor element by a conductive adhesive, A highly airtight material covering the anode lead wire side; and the high airtight material, the anode lead wire, the internal anode terminal, and the inside so that a part of the internal anode terminal and a part of the internal cathode terminal are exposed to the outside. A solid electrolyte comprising an exterior resin covering the cathode terminal, and an external anode terminal and an external cathode terminal connected to a part of the internal anode terminal and a part of the internal cathode terminal exposed to the outside from the exterior resin. Capacitors. 2. A dielectric oxide film and a solid electrolyte layer made of a conductive polymer on a surface of an anode body made of a valve metal in which an anode lead is embedded so that one end of the anode lead is exposed.
A capacitor element formed by sequentially forming a cathode layer, an internal anode terminal connected to one end of an anode lead wire of the capacitor element, and an internal anode terminal connected to a surface of the cathode layer of the capacitor element by a conductive adhesive. A cathode terminal, a highly airtight material covering the anode lead-out wire side of the capacitor element, and the highly airtight material, the anode so that a part of the internal anode terminal and a part of the internal cathode terminal are exposed to the outside; An exterior resin covering the lead wire, the internal anode terminal, and the internal cathode terminal, and an external anode terminal and an external cathode terminal connected to a part of the internal anode terminal and a part of the internal cathode terminal exposed to the outside from the exterior resin. And a solid electrolytic capacitor comprising: