JPH07272979A - Electrolytic capacitor - Google Patents

Abstract

PURPOSE:To manufacture effectivity and relatively at low costs by forming an insulating synthetic resin layer on the contact surface to the sealer of an external connecting terminal, without electrolyte leakage and dry up. CONSTITUTION:Relating to an electrolytic capacitor 10, an external connection terminal 14 and a capacitor element 12, formed by lapping an aluminum foil connected to 14, are housed in a case 16. The external connection terminal 14 is usually formed with an aluminum conductor 18, consisting of a rod part 18a and a flat part 18b, and an external leader line 20 which is connected to it. And so constituted as the rod part 18a is inserted and supported in an insertion part 22a of a gum elastic sealer 22, which seals an opening part of the armoring case 16, such as peroxide crosslinkng butyl rubber, etc. Further, the capacitor element 12 is impregnated with electrolyte containing the quaternary ammonium salt.

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 comprising a capacitor element impregnated with an electrolytic solution containing a quaternary ammonium salt (hereinafter may be simply referred to as an electrolytic capacitor). Is.

[0002]

2. Description of the Related Art Generally, in FIG. 4, an electrolytic capacitor 10 of this type has a capacitor element 12 in which aluminum foil and separator paper are alternately stacked, and external connection terminals 14 and 14 are connected to each aluminum foil. Above, it is configured to be housed in the outer case 16.
The external connection terminal 14 is formed of an aluminum conductor 18 including a round bar portion 18a and a flat portion 18b, and an external lead wire 20 connected to the aluminum conductor 18. The round bar portion 18a is configured to be inserted and supported in the insertion portion 22a of the sealing body 22 made of an elastic material, for example, elastic rubber, which seals the opening of the outer case 16. Further, the capacitor element 12 is impregnated with the electrolytic solution containing the quaternary ammonium salt as described above.

However, this type of electrolytic capacitor 10
In general, the contact surface of the external connection terminal (particularly the cathode side) 14 with respect to the sealing body 22, that is, the round bar portion 18a portion inserted and supported in the insertion portion 22a is poor in durability. Therefore, as a result of the electrochemical action of the electrolytic solution interposed in the insertion portion 22a, there is a problem that the liquid leakage increases. It should be noted that this means that the round bar portion 18a of the anode-side external connection terminal 14 has electrochemical resistance in the voltage treatment step (aging step) in the production of the capacitor, for example, by appropriately extending the step time. A conversion coating having can be formed. However, in the round bar portion 18a on the cathode side, the chemical conversion film is not formed because the applied voltage in the aging step is on the negative electrode side. Therefore, in the electrolytic capacitor 10 of this type, normally, by providing a special chemical conversion film forming step on the round rod portion 18a on the cathode side, it is possible to overcome the above-mentioned difficulty of liquid leakage.

However, the above-mentioned special conversion coating forming step requires a complicated and many steps, which causes disadvantages such as an increase in manufacturing cost and deterioration in quality.
Therefore, recently, at least a required portion of the external connection terminal (the round bar portion that is inserted and supported in the insertion portion of the sealing body).
By performing a chemical conversion treatment in advance before the capacitor manufacturing process, it is possible to eliminate the above-mentioned complicated and numerous processes and overcome the above-mentioned disadvantages, that is, increase in manufacturing cost and deterioration in quality. New technologies have been developed and proposed (see, for example, Japanese Patent Publication No. 60-32346).

[0005]

However, even in the above-mentioned new technology (hereinafter referred to as the conventional technology), there still exist some difficulties to be overcome.

That is, according to the above-mentioned prior art, the contact surface (the electrolytic solution containing the quaternary ammonium salt) of the external connection terminal (particularly the cathode side) is in contact with the contact surface (the sealing member insertion portion is a circle that is inserted and supported). Since the rod portion) is chemically treated as described above and has electrochemical resistance, the leakage current does not increase due to the action of the electrolytic solution. It can be manufactured at a cost.

However, in the above-mentioned prior art,
In the above configuration, the round bar portion that has been subjected to the chemical conversion treatment has ionic conductivity, and the pH of the electrolyte solution in contact therewith.
The value increases, so that the other contact surface (sealing body insertion part) that is in contact with this electrolytic solution acts on this electrolytic solution and deteriorates or deteriorates its physical properties. As a result, the sealing property of the sealing body is deteriorated, causing leakage of the electrolytic solution and deterioration of life characteristics due to dry-up of the electrolytic solution. The cause of the increase in the pH value of the electrolyte solution is not yet understood at present, but in reality,
A value of about 7 is raised to a pH value of about 10 to 14 when used.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrolytic capacitor which can be manufactured efficiently and at a relatively low cost without causing electrolyte leakage and dry-up.

[0009]

In order to achieve the above-mentioned object, an electrolytic capacitor according to the present invention stores a capacitor element impregnated with an electrolytic solution containing a quaternary ammonium salt in an outer case, In an electrolytic capacitor in which an opening of a case is sealed with a sealing body, an insulating synthetic resin layer is formed on a contact surface of the external connection terminal with the sealing body.

In this case, the external connection terminal is formed so as to include an aluminum conductor having a round bar portion and a flat portion, and the insulating synthetic resin layer is formed on the round bar portion in advance before the capacitor assembling process. Can be configured.

As another method, in an electrolytic capacitor in which a capacitor element impregnated with an electrolytic solution containing a quaternary ammonium salt is housed in an outer case and the opening of the outer case is sealed by a sealing plate, An insulating synthetic resin is formed on a contact surface of the rivet that connects the electrode tab and the external terminal to the sealing plate.

As still another method, a capacitor element impregnated with an electrolytic solution containing a quaternary ammonium salt is housed in an outer case, and the opening of the outer case is sealed with a sealing plate. It is characterized in that an insulating synthetic resin layer is formed on the internal electrode tabs that are led out and connected to the rivets.

The contact surface of the external connection terminal with respect to the sealing body or the sealing plate or the internal electrode tab may be treated with a coupling agent in advance and then the insulating synthetic resin layer may be formed. This makes it possible to maintain good adhesion of the insulating synthetic resin layer to the external connection terminal.

Furthermore, the insulating synthetic resin is 10% by weight.
You may make it obtain the same effect by containing a coupling agent in the following ratios.

[0015]

The insulating synthetic resin layer imparts electrochemical resistance to the external connection terminals and leaks when the electrolytic solution containing the quaternary ammonium salt and the external connection terminals made of the aluminum conductor come into contact with each other. An electric current is suppressed, while an insulating layer is formed for the electrolytic solution to prevent its deterioration. That is, since the pH value of the electrolytic solution increases and the shielding property of the sealing body or the sealing plate deteriorates, it is possible to prevent the electrolytic solution from leaking and drying up. Moreover, since the insulating synthetic resin layer is formed in advance before the capacitor assembling step, such an electrolytic capacitor can be efficiently manufactured at a relatively low cost.

[0016]

EXAMPLES Examples of electrolytic capacitors according to the present invention will now be described with reference to the accompanying drawings. For convenience of explanation, the same components as those of the conventional structure shown in FIGS. 4 and 5 are designated by the same reference numerals, and detailed description thereof will be omitted.

First, the basic structure of the electrolytic capacitor according to the present invention is the same as that of the conventional one. Therefore, although overlapping, but briefly described again, in FIG. 4, the electrolytic capacitor 10 has the external connection terminals 14, 14
The capacitor element 12 formed by winding aluminum foil connected to each other is housed in the outer case 16, and the external connection terminal 14 is usually an aluminum conductor 18 including a round bar portion 18a and a flat portion 18b. And an external lead wire 20 connected thereto. Then, the round bar portion 18a is provided in the outer case 16
It is configured so as to be inserted and supported in the insertion portion 22a of the sealing member 22 made of an elastic material for sealing the opening of, for example, an elastic rubber such as peroxide-crosslinked butyl rubber. The capacitor element 12 is impregnated with an electrolytic solution containing a quaternary ammonium salt.

In the present invention, as shown in FIGS. 1 to 3, the aluminum wire rod 30 is intermittently pressed.
(Fig. 1) is cut into a predetermined size 32a, 32b (Fig. 2)
On the round bar portion 18a of the aluminum conductor 18 including the round bar portion 18a and the flat portion 18b thus formed, a layer is formed using an insulating synthetic resin prior to the capacitor manufacturing process.

As the insulating synthetic resin material used,
For example, thermosetting resin such as epoxy, phenol, furan, melamine, xylene, guanamine resin, fluorine, butadiene, polyamide, polyamideimide, polyarylate, polyimide, polyetherimide, polyetheretherketone, polycarbonate, polyvinylformal, polyphenylenesulfide. , Liquid crystal polymers, ketones, coumarone, thermoplastic resins such as MBS resins, and the like. A coupling agent such as a silane-based or titanate-based coupling agent may be added to these in a proportion of 10% by weight or less.

That is, in the aluminum conductor 18,
Coupling agent is applied and dried to form coupling agent layer 34a.
After the formation of, or without applying a coupling agent as it is, a liquid melt of an insulating synthetic resin prepared by heating or using a suitable solvent is subjected to dipping treatment, roll coating, extrusion coating, or the like. By coating using various application means,
An insulating synthetic resin layer is formed on the aluminum conductor 18. Then, after that, the flat portion 18b is dipped in an appropriate solvent or subjected to ultrasonic treatment to remove the insulating synthetic resin material, and the insulating synthetic resin layer 34 (FIG. Allow 3) to remain. It should be noted that this coating operation was performed from the beginning on the round bar portion 1 of the aluminum conductor 18.
Alternatively, the insulating synthetic resin layer 34 may be applied only on the portion 8a.

Furthermore, the insulating synthetic resin layer 34 is used.
Is a heat-meltable synthetic resin film applied to the aluminum conductor 18 or the round bar portion 18a,
You may make it heat-process and form this.

Finally, an external lead wire 20 made of a CP wire is welded to the end surface of the round bar portion 18a to form the external connection terminal 14 (FIG. 3). In addition, this external connection terminal 1
The insulating synthetic resin layer 34 may be formed in advance on the entire surface of the wiring 4. Further, the manufacturing process of the capacitor using the external connection terminal 14 is the same as that of the conventional one, and therefore the description thereof will be omitted.

On the other hand, in the electrolytic capacitor according to the present invention, as shown in FIG. 5, the external connection terminal 14 is connected to the capacitor element 12 by the internal electrode tab 14a, and the rivet connected to the internal electrode tab 14a is inserted into the sealing plate 24. 14b and this rivet 14b are connected to the outside of the sealing plate 24 to form an external terminal 14c connected to an external lead wire. The sealing plate 24 is formed by attaching an elastic rubber 24a and a bake plate 24b to each other and providing an insertion portion 24c. It may be good. In this case, the insulating synthetic resin layer 34 is formed on the internal electrode tab 14a or the rivet 14b.

As described above, in the electrolytic capacitor of the present invention, the insertion support portion or the internal electrode tab for the sealing body or sealing plate of the external connection terminal, that is, the interposition portion of the electrolytic solution is electrochemically resistant to the external connection terminal. On the other hand, an insulating layer is formed for the electrolytic solution, and an insulating synthetic resin layer for preventing the deterioration is formed.

Hereinafter, specific examples will be described.

Example 1 97 parts by weight of an epoxy resin was mixed with 3 parts by weight of β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, coated on a round bar 18a with a roll, and dried sufficiently. An epoxy resin layer was formed.

Using this, an electrolytic capacitor was manufactured by a conventional method.

Example 2 98 parts by weight of phenol resin, N-β (aminoethyl) γ
An electrolytic capacitor was manufactured in the same manner as in Example 1 except that 2 parts by weight of aminopropyltrimethoxysilane was used.

Example 3 An electrolytic capacitor was manufactured in the same manner as in Example 1 except that 97 parts by weight of melamine resin and 3 parts by weight of isopropyltri (N-aminoethyl-aminoethyl) titanate were used.

Example 4 An electrolytic capacitor was manufactured in the same manner as in Example 1 except that 97 parts by weight of butadiene resin and 3 parts by weight of γ-methacryloxypropyltrimethoxysilane were used.

Example 5 A 3 wt% aqueous solution of γ-glycoside propyltrimethoxysilane was previously applied to the round bar portion 18a, and then a coating layer of polyphenylene sulfide was formed.

Then, an electrolytic capacitor was manufactured by using this product by a conventional method.

Example 6 Anode aluminum foil 12b and cathode aluminum foil 1
Separator paper 12c was alternately superposed between 2a and 2a and wound to form a capacitor element 12. The internal electrode tabs 14a, 14 connected to the respective aluminum foils 12a, 12b from the end face of the capacitor element 12
a was derived.

The capacitor element 12 is housed in the outer case 16, and the outer case 16 is sealed by the sealing plate 24 formed by bonding the bake plate 24b and the elastic rubber 24a. An insertion portion 24c (through hole) is provided in the sealing plate 24, and the rivet 14b is inserted therein. Rivet 14
The inner electrode tab 14a is provided at the end of the outer case 16 of FIG.
And the external terminal 14c at the end outside the outer case 16.
Connected.

In the electrolytic capacitor having the above-mentioned structure, the insulating synthetic resin layer 34 made of the synthetic resin used in Examples 1 to 5 was formed on the portion of the rivet 14b that abuts the sealing plate 24.

Example 7 An electrolytic capacitor was manufactured in the same manner as in Example 6 except that the insulating synthetic resin layer 34 was formed on the internal electrode tab 14a instead of the portion of the rivet 14b that abuts the sealing plate 24.

Comparative Example 1 Table 1 shows a comparison between the electrolytic capacitors according to Examples 1 to 5 of the present invention and the electrolytic capacitors of the conventional example, that is, using the external connection terminals in which the insulating synthetic resin layer is not formed. The experimental results are shown. In both experiments, the product rating was 25V.
220 μF, electrolyte; tetramethylammonium phthalate 25% by weight, γ-butyrolactone solution 75% by weight
The rated voltage (2
This is an observation of the state of electrolyte leakage after 2000 hours when 5 V) was applied. From the experimental results, in the conventional example, while liquid leakage has occurred,
It was confirmed that none occurred in the examples of the present invention.

[0038]

[Table 1]

Comparative Example 2 The electrolytic capacitor manufactured in Example 6 was tested under the same conditions as in Comparative Example 1 and then observed for spillage. No occurrence of spillage was confirmed, and an insulating synthetic resin layer was provided on the rivet. The effect of preventing liquid discharge when provided was confirmed.

Comparative Example 3 The electrolytic capacitor manufactured in Example 7 was tested under the same conditions as in Comparative Example 1 and then observed for liquid discharge. No occurrence of liquid discharge was confirmed, and an insulating synthetic resin layer was formed on the electrode tab. It was confirmed that the product provided with the above also has a liquid discharge preventing effect.

[0041]

As described above, in the electrolytic capacitor according to the present invention, the capacitor element impregnated with the electrolytic solution containing the quaternary ammonium salt is housed in the outer case, and the opening of the outer case is sealed. Or, in the electrolytic capacitor sealed by the sealing plate, by forming an insulating synthetic resin layer on the contact surface of the external connection terminal of the electrolytic capacitor or the electrode tab to the sealing body or the sealing plate, the electrolytic solution Electrochemical resistance is given to the external connection terminal or the electrode tab on the surface of the external connection terminal at the portion where is intervened, while an insulating layer is formed against the electrolytic solution to prevent its deterioration. By forming an insulative synthetic resin layer that protects the electrolytic capacitor from leakage of electrolyte due to deterioration of the shielding performance of the sealing body or sealing plate due to electrochemical action, It is possible to prevent the line-up. In this case, since the coating layer is formed in advance before the capacitor assembling process, there is an advantage that the electrolytic capacitor can be manufactured efficiently and at a relatively low cost.

[Brief description of drawings]

FIG. 1 is a side view showing a step of pressing an external connection terminal aluminum conductor in an electrolytic capacitor according to the present invention.

FIG. 2 is a plan view showing a step of cutting the aluminum conductor shown in FIG.

FIG. 3 is a side view showing an external connection terminal in the electrolytic capacitor according to the present invention.

FIG. 4 is a cross-sectional view showing a general configuration of an electrolytic capacitor.

FIG. 5 is a cross-sectional view showing the configuration of another example of an electrolytic capacitor.

[Explanation of symbols]

 10 Electrolytic Capacitor 12 Capacitor Element 12a Cathode Aluminum Foil 12b Anode Aluminum Foil 12c Separator Paper 14 External Connection Terminal 14a Internal Electrode Tab 14b Rivet 14c External Terminal 16 Exterior Case 18 Aluminum Conductor 18a Round Bar 18b Flat Part 20 External Lead Wire 22 Sealing Body 22a Insertion Portion 24 Sealing Plate 24a Elastic Rubber 24b Bake Plate 24c Insertion Portion 30 Aluminum Wire Rods 32a, 32b Cutting Wire 34 Insulating Synthetic Resin Layer 34a Coupling Agent Layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minasa Sasaki 1-167-1, Higashi-Ome, Ome-shi, Tokyo Inside Nippon Chemi-Con Corporation

Claims (4)

[Claims] 1. An electrolytic capacitor in which a capacitor element impregnated with an electrolytic solution containing a quaternary ammonium salt is housed in an outer case, and an opening of the outer case is sealed with a sealing body, wherein the external connection terminal is An electrolytic capacitor having an insulating synthetic resin layer formed on a contact surface with respect to a sealing body. 2. The external connection terminal includes an aluminum conductor having a round bar portion and a flat portion, and the insulating synthetic resin layer comprises:
The electrolytic capacitor according to claim 1, wherein the round bar portion is formed in advance before a capacitor assembling step. 3. An electrolytic capacitor in which a capacitor element impregnated with an electrolytic solution containing a quaternary ammonium salt is housed in an outer case, and an opening of the outer case is sealed with a sealing plate, wherein internal electrode tabs and external terminals are provided. An electrolytic capacitor, characterized in that an insulating synthetic resin layer is formed on a contact surface of a rivet for connecting with the sealing plate. 4. An electrolytic capacitor in which a capacitor element impregnated with an electrolytic solution containing a quaternary ammonium salt is housed in an outer case, and an opening of the outer case is sealed by a sealing plate, and a rivet led out from the capacitor element. An electrolytic capacitor, wherein an insulating synthetic resin layer is formed on an internal electrode tab connected to.