JPH1167600A - Electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of a liquid leakage from the cathode part of an electrolytic capacitor by a method wherein a film consisting of a metal nitride film or a metal film is formed on the surface of a cathode electrode foil and at the same time, an insulating layer consisting of an anode oxide film layer is formed on the surface of a cathode lead-out means. SOLUTION: As an anode foil 2, one obtainable by a method, wherein an aluminium foil of a purity of 99 % or higher is etched to be subjected to surface enlarging treatment of the foil and thereafter, a chemical formation treatment is performed on the foil and an anode oxide film layer is formed on the surface of the foil, is used. As a cathode foil 3, one obtainable by etching an aluminium foil of a purity of 99% or higher is used and a film consisting of a metal nitride film or a metal film is formed on one part of the surface of the foil 3 or the whole surface of the foil 3. Moreover, an insulating layer is formed on one part of the surface of a lead wire 5 or the whole surface of the wire 5. Such a capacitor element 1 is impregnated with an electrolyte for electrolyte capacitor drive use. As the electrolyte, an electrolyte obtainable by a method, wherein salt, which contains a γ-butyrolactone and an ethylene glycol as its main solvent, contains an acid conjugate base as its anion component and contains a quaternized cyclic amidinium as its cation component, is dissoled and moreover, an oxidizing reagent is added to the dissolved salt, is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic capacitor, and more particularly to an electrolytic capacitor using a quaternary cyclic amidinium ion as a cation component as an electrolytic solution.

[0002]

2. Description of the Related Art An electrolytic capacitor generally has a structure as shown in FIG. That is, the strip-like high-purity aluminum foil is chemically or electrochemically etched to enlarge the aluminum foil surface, and the aluminum foil is subjected to a chemical conversion treatment in a chemical conversion solution such as an ammonium borate aqueous solution. An anode electrode foil 2 having an oxide film layer formed on the surface thereof and a cathode electrode foil 3 made of a high-purity aluminum foil subjected to only an etching treatment are wound through a separator 11 made of manila paper or the like to form a capacitor. An element 1 is formed. And this capacitor element 1
Is impregnated with an electrolytic solution for driving an electrolytic capacitor, and then stored in a bottomed cylindrical outer case 10 made of aluminum or the like. A sealing body 9 made of elastic rubber is attached to the opening of the outer case 10, and the outer case 10 is sealed by drawing.

As shown in FIG. 2, lead wires 4 and 5, which are electrode lead means for pulling out electrodes of both electrodes, are stitched on the anode electrode foil 2 and the cathode electrode foil 3, respectively.
They are connected by means such as ultrasonic welding. Each of the lead wires 4 and 5 as the electrode lead-out means comprises a round bar portion 6 made of aluminum and a connecting portion 7 in contact with the bipolar electrode foils 2 and 3. An external connection portion 8 made of a possible metal is fixed by means such as welding.

Various electrolytic solutions for driving an electrolytic capacitor impregnated in the capacitor element 1 are known depending on the performance of the electrolytic capacitor used.
A salt in which butyrolactone was used as a main solvent and a tetraalkylammonium ion or a tetraalkylphosphonium ion was used as a cation component as a solute and a conjugate base of an acid was used as an anion component, so-called quaternary ammonium salts, and quaternary phosphonium salts were dissolved. (For example, JP-A-62-264615, JP-A-62-145713).
No.).

[0005]

The electrolytic solution using the quaternary ammonium salt or the like has a low electric resistance and excellent thermal stability.
There is a tendency that the electrolyte is easily discharged from the through hole for the purpose. For this reason, although the stability of the electrolytic solution itself using a quaternary ammonium salt or the like is high, since the electrolytic solution is discharged, the electric characteristics such as a decrease in the capacitance of the electrolytic capacitor are deteriorated, and as a result, the electrolytic solution is deteriorated. There is a disadvantage that the life of the capacitor is short.

[0006] Recent studies have shown that such leaching of the electrolyte occurs due to the electrochemical action of the electrolyte using quaternary ammonium. In a general electrolytic capacitor, a leakage current is generated between the anode electrode foil 2 and the cathode electrode foil 3 when a DC voltage is applied due to damage of an oxide film formed on the anode electrode foil 2 or the like. The occurrence of such a leakage current causes a reduction reaction of dissolved oxygen or hydrogen ions on the cathode side, and increases the concentration of hydroxide ions at the interface between the cathode side electrode and the electrolyte. This occurs in both the cathode electrode foil 3 and the cathode lead wire 5, and in particular, an increase in hydroxide ion concentration near the cathode lead lead wire 5, that is, an increase in basicity is observed. Can be And
With the increase in the basicity, the sealing body 9 in contact with the lead wire 5 is damaged, and the adhesion between the lead wire 5 and the sealing body 9 is impaired. It is believed that the material solution has leaked out.

That is, as shown in FIG. 3 (a), the leakage current of the electrolytic capacitor is the current I ₂ flowing through the cathode electrode foil 3 and the current I ₁ flowing through the cathode lead wire 5 in the cathode portion. It is sum. Time Normally, the direction of spontaneous potential E ₁ of the lead wire 5 for the cathode lead-out indicates a noble potential than the natural potential E ₂ of the cathode electrode foil 3, the cathode side is the cathode polarization in DC load state, first, the lead An electric current flows through the line 5 to cause a reduction reaction of dissolved oxygen or hydrogen ions. Then, a current that cannot be processed by the reduction reaction of dissolved oxygen or hydrogen ions on the lead wire 5 flows through the cathode electrode foil 3 and a reduction reaction of dissolved oxygen or hydrogen ions on the cathode electrode foil 3 occurs. The active surface area of the cathode electrode foil 3 is larger than the active surface area of the lead wire 5.
Is smaller than the polarization resistance of the lead wire 5.
Therefore, the potential E _T becomes the rated value I _T of the leakage current of the electrolytic capacitor, although the direction of current I ₂ flowing in the cathode electrode foil 3 is large, a state in which current I ₁ also leads 5 are flowing. Therefore, in a DC load state, a state in which current also flows through the lead wire 5 for cathode extraction continues, and the lead wire 5
The reduction reaction of dissolved oxygen or hydrogen ions always occurs on the surface of the substrate, and the generated basic hydroxide ion causes deterioration of sealing accuracy.

[0008] Such behavior of the electrolyte at the interface between the electrode foil and the lead wire can similarly occur in an electrolyte containing no quaternary ammonium salt. For example, when a tertiary ammonium salt is used, It is considered that there was no generation of the basic salt itself, or that the generated cation had high volatility, and thus no inconvenience such as liquoring occurred.

Recently, an international application, PCT / JP94
As shown in US Pat. No./02028, attempts have been made to prevent the leaching of the electrolytic solution by using a quaternized cyclic amidinium salt instead of a quaternary ammonium salt or a quaternary phosphonium salt. This quaternized cyclic amidinium salt can considerably suppress the leaching of the electrolytic solution as compared with the case where a conventional quaternary ammonium salt or quaternary phosphonium salt is used, but in both a loaded state and an unloaded state. Is not yet a practical level.

An object of the present invention is to improve this drawback and to prevent the effusion of an electrolytic capacitor using a quaternized cyclic amidinium salt or the like and improve the life characteristics.

[0011]

SUMMARY OF THE INVENTION The present invention comprises an anode electrode foil provided with anode extraction means, a cathode extraction means having an insulating layer formed on part or all of the surface, and a metal partly or entirely provided on the surface. A capacitor electrode is formed by winding a cathode electrode foil on which a film made of a nitride or a metal is formed via a separator, and impregnating the capacitor element with an electrolytic solution containing a quaternary salt of a cyclic amidine compound and an oxidizing agent. And housed in a bottomed cylindrical outer case.

The insulating layer formed on a part or all of the surface of the cathode lead-out means is formed of an anodic oxide film layer made of aluminum oxide, and is a metal nitride covering a part or all of the surface of the cathode electrode foil. Examples of the metal include titanium nitride, zirconium nitride, tantalum nitride, and niobium nitride, and examples of the metal include titanium, zirconium, tantalum, and niobium. As the oxidizing agent added to the electrolyte,
Nitro compounds can be used. Further, the cathode extraction means includes a round bar portion made of aluminum and a flat connection portion, and the insulating layer covers at least substantially the entire surface of the round bar portion. It is further preferable that the anode extraction means includes a round bar portion made of aluminum and a flat connection portion, and the insulating layer made of aluminum oxide covers at least substantially the entire surface of the round bar portion. .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of an aluminum electrolytic capacitor has the same structure as that of the prior art, as shown in FIGS. The capacitor element 1 is formed by winding an anode foil 2 and a cathode foil 3 with a separator 8 interposed therebetween. As shown in FIG. 2, the anode foil 2 and the cathode foil 3 are connected to a lead wire 4 and a lead wire 5 serving as an anode lead-out means and a cathode lead-out means, respectively. These lead wires 4 and 5 are composed of a connecting portion 7 connected to each foil, a round bar portion 6 continuous with the connecting portion 7, and an external connecting portion 8 welded to the round bar portion 6. . The respective foils and lead wires are mechanically connected by a stitch method, ultrasonic welding, or the like.

The anode foil 2 is obtained by chemically or electrochemically etching an aluminum foil having a purity of 99% or more in an acidic solution and expanding the surface thereof, and then performing a chemical conversion treatment in an aqueous solution of ammonium borate or ammonium adipate. And use an anodic oxide film layer formed on the surface.

The cathode foil 3 is obtained by etching an aluminum foil having a purity of 99% or more in the same manner as the anode foil 2. Then, a film made of metal nitride or metal is formed on part or all of the surface of the cathode foil 3. As the metal nitride, titanium nitride, zirconium nitride,
Examples of the metal include tantalum nitride and niobium nitride, and examples of the metal include titanium, zirconium, tantalum, and niobium.
Further, an insulating layer is formed on part or all of the surface of the lead wire 5. Examples of the insulating layer include an anodic oxide film made of aluminum oxide obtained by a chemical conversion treatment using an aqueous solution of ammonium borate, an aqueous solution of ammonium phosphate, or an aqueous solution of ammonium adipate. Further, it is preferable that at least substantially the entire surface of the round bar portion 6 of the lead wire 5 be covered. Also,
More preferably, the lead wire 4 includes an insulating layer similar to the lead wire 5.

The capacitor element 1 constructed as described above
Is impregnated with an electrolytic solution for driving an electrolytic capacitor. As the electrolyte, γ-butyrolactone or ethylene glycol is used as a main solvent, a conjugate base of an acid is used as an anion component, a salt having a quaternary cyclic amidinium as a cation component is dissolved, and an electrolyte solution further containing an oxidizing agent is used. .

Examples of the acid serving as the anion component include phthalic acid, isophthalic acid, terephthalic acid, maleic acid, benzoic acid, toluic acid, enanthic acid, and malonic acid.

The quaternized cyclic amidinium ion serving as the cation component is a cation obtained by quaternizing a cyclic compound having an N, N, N'-substituted amidine group.
Examples of the cyclic compound having an N′-substituted amidine group include the following compounds. Imidazole monocyclic compound (1-
Methylimidazole, 1-phenylimidazole, 1,
Imidazole homologs such as 2-dimethylimidazole, 1-ethyl-2-methylimidazole, 1,2-dimethylimidazole, 1-ethyl-2-methylimidazole, 1,2-dimethylimidazole, 1,2,4-trimethylimidazole Oxyalkyl derivatives such as 1-methyl-2-oxymethylimidazole, 1-methyl-2-oxyethylimidazole, nitro derivatives such as 1-methyl-4 (5) -nitroimidazole, and 1,2-dimethyl-
Amino derivatives such as 5 (4) -aminoimidazole, etc.),
Benzimidazole compounds (such as 1-methylbenzimidazole, 1-methyl-2-benzimidazole, 1-methyl-5 (6) -nitrobenzimidazole), and compounds having a 2-imidazoline ring (1-methylimidazoline, 1,2 -Dimethylimidazoline, 1,2,4-trimethylimidazoline, 1-methyl-2-phenylimidazoline, 1-ethyl-2-methyl-imidazoline, 1,
4-dimethyl-2-ethylimidazoline, 1-methyl-
2-ethoxymethylimidazoline and the like, and compounds having a tetrahydropyrimidine ring (1-methyl-1,4,5,5)
6-tetrahydropyrimidine, 1,2-dimethyl-1,
4,5,6-tetrahydropyrimidine, 1,5-diazabicyclo [4,3,0] nonene-5 and the like.

As the oxidizing agent, nitro compounds such as nitrobenzoic acids, nitroanisole, nitrophenol and nitronaphthol can be used.

The capacitor element 1 impregnated with the electrolytic solution as described above is housed in an outer case 10 made of aluminum having a bottomed cylindrical shape, and lead wires 4 and 5 are led out to the open end of the outer case 10. The sealing of the electrolytic capacitor is performed by inserting a sealing member 9 made of butyl rubber having a hole and crimping the end of the outer case 10.

The above electrolytic capacitor of the present invention has a very good bleeding characteristic. The reason is presumed to be as follows.

As described above, in the electrolytic capacitor using the electrolytic solution containing a quaternary ammonium salt, the natural potential of the lead wire 5 for drawing out the cathode is more noble than the natural potential of the cathode electrode foil 3. At the time of loading, the cathode current concentrates on the lead wire 5, and the generated basic hydroxide ion causes deterioration of sealing accuracy.

Further, in the case of an electrolytic solution in which a quaternized amidinium salt is dissolved, such hydroxide ions generated by the reduction reaction of dissolved oxygen or hydrogen ions react with the quaternized amidinium and disappear. It was thought that bleeding could be prevented. However, it was found that when the pH value at the interface between the cathode-side electrode and the electrolytic solution was 12 or less, the reaction between hydroxide ions and quaternized amidinium did not completely proceed, and hydroxide ions remained. Thus, although liquor is improved over quaternary ammonium salts, it cannot be completely suppressed.

On the other hand, in the present invention, a film made of metal nitride is formed on the surface of the cathode electrode foil, and an insulating layer made of an anodic oxide film layer is formed on the surface of the cathode extraction means. Therefore, as shown in FIG. 3B, the natural potential E ₂ of the cathode electrode foil is changed to the natural potential E ₂ of the cathode extraction means.
_The potential becomes more noble than _1, and the potentials of the cathode electrode foil and the cathode extraction means can be reversed.

That is, when a direct current is applied in the present invention, first, a current flows through the cathode electrode foil, and a reduction reaction of dissolved oxygen or hydrogen ions occurs on the cathode electrode foil.
The reduction reaction of the oxidizing agent in the electrolytic solution is combined with the reduction reaction, so that the polarization resistance of the cathode electrode foil having an active surface area larger than that of the cathode extraction means is significantly smaller than the polarization resistance of the cathode extraction means. Therefore the potential E _T as a rated value I _T of the leakage current of the electrolytic capacitor is significantly shifted in the direction of the noble in comparison with the conventional potential E _T. Then, the insulating layer formed on the surface of the cathode lead-out means is further suppressing the current I _1, generation of basic hydroxide in the vicinity of the cathode lead-out means is not observed almost reduce the adverse effect on the sealing body or the like Will be able to

A technique for coating a metal nitride such as titanium nitride on the cathode electrode foil by means such as vapor deposition has been proposed (for example, Japanese Patent Application Laid-Open No. 2-117123,
JP-A-4-61109, JP-A-4-329620
No.). However, these proposals aim at increasing the surface area on the cathode foil side, and do not aim at reversing the potentials of the cathode electrode foil and the cathode extracting means as in the present invention. That is, since the present invention does not intend to increase the surface area, it is not necessary to cover the entire surface of the cathode electrode foil with the metal nitride. For example, it has been confirmed that the same effect can be obtained if only one surface is coated with titanium nitride, or if titanium nitride is coated in a certain ratio of area. Further, even if only the cathode electrode foil whose surface is coated with titanium nitride is used, the current I ₁ flowing through the lead wire on the cathode side shown in FIG. 3B cannot be completely suppressed.
As a result, it has been confirmed that liquid is discharged by applying a long-time DC current.

When the battery is left without any load, in a conventional electrolytic capacitor, since the potential of the lead wire 5 and the potential of the cathode foil are different, a local battery is constituted by the lead wire 5 and the cathode foil. Then, as described above, the natural immersion potential E ₁
Shows a nobleer potential than the spontaneous immersion potential E ₂ of the cathode foil, so that a reduction reaction of dissolved oxygen or hydrogen ions occurs near the lead wire 5 to generate hydroxide ions, thereby increasing the sealing accuracy. It will cause deterioration.

However, in the present invention, an electrode foil having a coating made of metal nitride or metal formed on a part or all of the surface of the cathode foil is used, and the natural immersion potential E ₂ of the cathode foil leads to the lead. since than the natural immersion potential E ₁ line 5 shows the noble potential, the reduction reaction of dissolved oxygen or hydrogen ion occurs at the cathode foil side. That is, hydroxide ions are not generated in the vicinity of the lead wire 5, and therefore, there is no possibility that the adhesion accuracy between the lead wire 5 and the sealing rubber is deteriorated and liquid is discharged.

Further, when the external connection portion on the anode side and the external connection portion on the cathode side come into contact with each other when no load is left, if the lead wire 4 is made of aluminum or the like which is more noble than the cathode foil, the anode side can be used. A local battery is formed by the lead wire 4 and the cathode foil, and a reduction reaction of dissolved oxygen or hydrogen ions occurs near the lead wire 4. As a result, hydroxide ions are generated on the anode side, causing deterioration in sealing accuracy. Therefore, the lead wire 4 includes a round bar portion made of aluminum and a flat connection portion, and the insulating layer made of aluminum oxide covers at least almost the entire surface of the round bar portion, so that the lead wire 4 is lower than the cathode foil. Preferably.

For the reasons described above, in the present invention, it is considered that the liquid is prevented from being discharged regardless of whether the load is applied or not.

[0031]

Next, the present invention will be described with reference to embodiments. Since the structure of the electrolytic capacitor is the same as that of the related art, it will be described with reference to FIGS. The capacitor element 1 is formed by winding an anode electrode foil 2 and a cathode electrode foil 3 with a separator 11 interposed therebetween. As shown in FIG. 2, the anode electrode foil 2 and the cathode electrode foil 3 have a lead wire 4 for leading the anode,
Lead wires 5 for drawing out the cathode are connected to each other.

The lead wires 4, 5 are connected to a connecting portion 7 in contact with the electrode foil, a round bar portion 6 formed integrally with the connecting portion 7, and an external connecting portion 8 fixed to the tip of the round bar portion 6. Become. The connecting portion 7 and the round bar portion 6 are made of 99% aluminum, and the external connecting portion 8 is made of a copper-plated steel wire (hereinafter referred to as a CP wire). An anodic oxide film made of aluminum oxide is formed on at least the surface of the round bar portion 6 of the lead wires 4 and 5 by a chemical conversion treatment with an ammonium phosphate aqueous solution. The lead wires 4 and 5 are electrically connected to the bipolar electrode foils 2 and 3 at the connection portions 7 by means such as stitching and ultrasonic welding.

The anode electrode foil 2 is obtained by chemically or electrochemically etching an aluminum foil having a purity of 99.9% in an acidic solution and expanding the surface thereof, and then performing a chemical conversion treatment in an aqueous solution of ammonium adipate. An anodic oxide film layer is formed on the surface.

The cathode electrode foil 3 is obtained by etching an aluminum foil having a purity of 99.9% similarly to the anode electrode foil 2. The entire surface of the cathode electrode foil 3 is coated with titanium nitride or zirconium nitride by a vapor deposition method. In this embodiment, the coating layer made of a metal nitride such as titanium nitride covers the entire surface of the cathode electrode foil 3, but if necessary, a part of the cathode electrode foil 3, for example, the cathode electrode foil 3. Only one surface may be coated with the metal nitride.

The capacitor element 1 configured as described above
Is impregnated with an electrolytic solution for driving an electrolytic capacitor. As an electrolyte, γ-butyrolactone (75 parts) was used as a solvent,
As a solute, mono1,2,4-trimethylimidazoline (methyl) phthalate phthalate (25 parts) was dissolved, and one part of an oxidizing agent was added.

The capacitor element 1 impregnated with the electrolytic solution as described above is housed in an outer case 10 made of aluminum having a bottomed cylindrical shape, and a sealing body 9 is attached to the opening of the outer case 10. Is subjected to a drawing process to seal the outer case 10. The sealing body 9 is made of an elastic rubber such as butyl rubber, for example, and has through holes for leading the lead wires 4 and 5, respectively.

An electrolytic capacitor configured as described above,
A comparative example and a conventional electrolytic capacitor were compared. The conditions were as follows: a rated voltage of 35 V was applied at 105 ° C. for 2,000 hours; The results are shown in (Table 1). Also, at 105 ° C, 2
After leaving for 000 hours, the presence or absence of the electrolyte was similarly determined. The results are shown in (Table 2).

[0038]

[Table 1]

[0039]

[Table 2]

As is clear from (Table 1) and (Table 2),
In both cases of loading and no loading, when a quaternary salt of cyclic amidine was used as a solute of the electrolytic solution, as seen in Comparative Example 3 in which a film made of metal nitride was formed on the cathode electrode foil,
Although the bleeding can be suppressed to some extent, it is difficult to completely control the bleeding. Also, in Comparative Example 6 in which an oxidizing agent such as a nitro compound was added to the electrolytic solution, it was not possible to prevent bleeding, and for example, aluminum oxide was added to the round bar portion of the lead wire on the cathode side as a means for leading the cathode electrode. Also in Comparative Example 5 in which an insulating layer such as an anodic oxide film was formed, bleeding was not prevented. Furthermore, two of the above three elements of forming a metal nitride film on the cathode electrode foil, adding an oxidizing agent to the electrolytic solution, and forming an insulating layer on the round bar portion of the lead wire. Also in Comparative Examples 1, 2, and 4 in which the elements are combined, it is not possible to completely prevent the liquid from flowing out. In Examples 1 and 2 in which all three elements described in the present application are combined, it is possible to completely prevent the liquid from flowing out.

Next, another embodiment of the present invention will be described. The structure and manufacturing method of the capacitor were the same as those in the above-described embodiment, and the round bar portion of the lead wire was subjected to a chemical conversion treatment in ammonium phosphate. Γ─butyrolactone (7
5 parts) as a solvent and monophthalic acid 1,2,4 as a solute
A solution obtained by dissolving a quaternary salt of a cyclic amidine compound other than trimethylimidazoline (methyl) quaternized salt (25 parts) and adding 1 part of paranitrophenol as an oxidizing agent was used. The conditions are as follows: 2,000 hours at 105 ° C, rated voltage 35
A V load was applied, and a determination was made as to whether or not the electrolyte had subsequently drained. The results are shown in (Table 3). 105 ° C
For 2,000 hours, and the same judgment was made as to whether or not the electrolyte was discharged. The results are shown in (Table 4). Each test was performed in a closed state.

[0042]

[Table 3]

[0043]

[Table 4]

As apparent from (Table 3) and (Table 4),
Example 3 using a quaternary salt of a cyclic amidine compound other than mono 1,2,4-trimethylimidazoline (methyl) phthalate in the present invention in both cases with and without loading.
Also in Nos. To 5, the bleeding was completely suppressed.

[0045]

According to the present invention, a film made of metal nitride or metal is formed on the surface of the cathode electrode foil,
Since the insulating layer composed of the anodic oxide film layer is formed on the surface of the cathode extraction means, the potentials of the cathode electrode foil and the cathode extraction means can be reversed. And the potential of the cathode electrode foil can be made more dominant by the reducing action of the oxidizing agent in the electrolytic solution. Further, an insulating layer made of an anodic oxide film is formed on the surface of the anode extraction means, so that the potential of the cathode foil can be made superior. Therefore, in both loading and unloading, it is possible to prevent the liquid from the cathode electrode drawing means or the anode electrode drawing means in the electrolytic capacitor using the quaternary salt of the cyclic amidine compound as a solute of the electrolytic solution, A decrease in capacitance due to a decrease in the electrolytic solution is prevented, and the life of the electrolytic capacitor can be extended and the reliability can be increased.

[Brief description of the drawings]

FIG. 1 is an internal sectional view showing a structure of an electrolytic capacitor.

FIG. 2 is an exploded perspective view showing the structure of the capacitor element.

FIG. 3 is a graph showing cathode polarization resistance at a cathode portion of an electrolytic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Anode electrode foil 3 Cathode electrode foil 4 Lead wire for anode drawing 5 Lead wire for cathode drawing 6 Round bar part 7 Connection part 8 External connection part 9 Sealing body 10 Exterior case 11 Separator

Claims (6)

[Claims] 1. An anode electrode foil provided with anode extraction means,
A cathode electrode foil having a cathode extraction means having an insulating layer formed on part or all of the surface and a cathode electrode foil having a coating made of metal nitride or metal formed on part or all of the surface; An electrolytic capacitor in which an element is formed, the capacitor element is impregnated with an electrolytic solution containing a quaternary salt of a cyclic amidine compound and an oxidizing agent, and is housed in an outer case. 2. The electrolytic capacitor according to claim 1, wherein the insulating layer formed on part or all of the surface of the cathode extraction means is an anodic oxide film layer made of aluminum oxide. 3. The electrolytic capacitor according to claim 1, wherein the metal nitride is titanium nitride, zirconium nitride, tantalum nitride, and niobium nitride, and the metal is titanium, zirconium, tantalum, and niobium. 4. The electrolytic capacitor according to claim 1, wherein the oxidizing agent is a nitro compound. 5. The method according to claim 1, wherein the cathode extracting means comprises:
An electrolytic capacitor including a round bar portion made of aluminum and a flat connecting portion, wherein the insulating layer covers at least substantially the entire surface of the round bar portion. 6. The anode drawing means according to claim 1,
An electrolytic capacitor including a round bar portion made of aluminum and a flat connection portion, wherein an insulating layer made of aluminum oxide covers at least substantially the entire surface of the round bar portion.