JP2943289B2 - Aluminum electrolytic capacitor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum electrolytic capacitor used for various electronic devices.

2. Description of the Related Art Conventionally, this type of aluminum electrolytic capacitor has a configuration as shown in FIG. That is, an anode foil 1 having a dielectric oxide film formed on the surface of a roughened aluminum foil by anodic oxidation and a cathode foil 2 made of an aluminum foil are opposed to each other, and a separator paper is provided between the anode foil 1 and the cathode foil 2. 3 to form a capacitor element 4 by winding
And impregnating the capacitor element 4 with a driving electrolyte,
Thereafter, the capacitor element 4 is housed in a bottomed cylindrical metal case 5 made of aluminum, and a pair of lead wires 4a and 4b connected to the capacitor element 4 are externally inserted into the opening of the metal case 5. The elastic sealing body 6 is attached so as to be drawn out, and the metal case 5 and the elastic sealing body 6 are wound and sealed so that the driving electrolyte inside the metal case 5 does not evaporate. Was.

Problems to be Solved by the Invention The anode foil 1 and the cathode foil 2 in the above-mentioned conventional aluminum electrolytic capacitor are, as shown in FIG. 4, provided by an amount of a required length from a roll foil 7 previously cut to a required width. By cutting and winding them in a positional relationship as shown in FIG. 5, that is, a positional relationship in which the separator paper 3 is interposed between the anode foil 1 and the cathode foil 2, the capacitor element 4 Is configured.

However, as shown in FIG. 4, the anode foil 1 and the cathode foil 2, which are cut by the required length, have both ends.
When cutting 8a and 8b, as shown in FIG.
Was pressed in a direction perpendicular to the foil surface, so that cutting burrs 10 were generated. Such cutting burrs 10
When the anode foil 1 and the cathode foil 2 are wound together with the separator paper 3 to form the capacitor element 4 in the state where the cracks have occurred, the cutting burrs 10 break through the separator paper 3 and the anode foil 1
And the cathode foil 2 are brought into contact with each other, thereby causing a problem that a short circuit increases.

On the other hand, for the purpose of improving such problems, a method of manufacturing an aluminum electrolytic capacitor in which the adhesive tape of polypropylene or the like is wrapped around both ends of the electrode foil to cover the cut portions at both ends of the electrode foil. (Japanese Patent Publication No. 63-1275
No. 27) has been proposed, but since the adhesive tape such as polypropylene does not allow the driving electrolyte to penetrate, when the cut portions at both ends of the electrode foil are covered with the adhesive tape such as polypropylene, The coating portion is not impregnated with the driving electrolyte during the impregnation, so that the initial capacitance may be low or the dielectric oxide film of the anode foil portion covered with an adhesive tape such as polypropylene may be used. There was a problem that it could not be repaired.

When a load test is performed with the dielectric oxide film of the anode foil not repaired, the driving electrolyte gradually penetrates from the gap between the coated adhesive tape such as polypropylene and the electrode foil, increasing the leakage current. There is also a problem that the reliability is significantly reduced.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide an aluminum electrolytic capacitor which does not cause a short circuit failure and can also satisfactorily repair a dielectric oxide film of an anode foil. It is.

Means for Solving the Problems To achieve the above object, the aluminum electrolytic capacitor of the present invention includes a capacitor element configured by being wound with a separator paper interposed between an anode foil and a cathode foil, The entire front and back surfaces of the cut portions at both ends in the longitudinal direction of the anode foil and the cathode foil are covered with a tape, and the tape is formed on the entire surface of one side of a base material made of a material that allows the drive electrolyte to penetrate. It is configured by applying an adhesive that allows the penetration of the adhesive.

Action According to the above configuration, since the entire front and back surfaces of the cut portions at both ends in the length direction of the anode foil and the cathode foil are covered with the tape, the coated tape has cut burrs at the cut portions at both ends of the electrode foil. , Make a space between the electrode foil opposite to this,
Winding stress generated between the cutting burrs of the electrode foil and the electrode foil of the counter electrode can be absorbed, thereby ensuring that the cutting burrs break through the separate paper and contact the anode foil and the cathode foil. Short-circuit failure does not occur.

Further, since the tape is formed by applying an adhesive that allows the driving electrolyte to penetrate over the entire surface of one side of the substrate made of a material that allows the driving electrolyte to permeate, the tape is used to form an anode foil and a cathode foil. Even when covering the entire front and back surfaces of the cut portions at both ends in the length direction, at the time of impregnation of the driving electrolyte, this driving electrolyte will impregnate the cut portion,
Therefore, since the dielectric oxide film of the anode foil is repaired with the driving electrolyte, the characteristics are not deteriorated.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a positional relationship of members constituting a capacitor element of an aluminum electrolytic capacitor according to an embodiment of the present invention.
Only different points from the conventional example will be described. That is, in the embodiment of the present invention, the tape 11 covers the entire front and back surfaces of the cut portions at both ends of the anode foil 1 and the cathode foil 2 in the longitudinal direction.
Is formed by applying a pressure-sensitive adhesive that allows the driving electrolyte to penetrate over the entire surface of one side of a substrate made of a material that allows the driving electrolyte to penetrate.

Next, experimental examples for comparing each embodiment of the present invention with a conventional example will be described.

(Example 1) A tape formed by applying a pressure-sensitive adhesive that allows a driving electrolytic solution to permeate the entire surface of one side of the base material, using manila paper constituting a separator paper of an aluminum electrolytic capacitor as a base material, The tape covers the entire front and back surfaces of the cut portions at both ends in the longitudinal direction of the anode foil 1 and the cathode foil 2 shown in FIG.
The anode foil 1 and the cathode foil 2 are wound together with the separator paper 3 to form a capacitor element 4. The capacitor element 4 is impregnated with a driving electrolyte, and the capacitor element 4 is made of a metal made of aluminum. An aluminum electrolytic capacitor having a rated voltage of 10 V and 100 μF was sealed in the case 5.

(Example 2) An aluminum electrolytic capacitor was produced in the same manner as in Example 1 except that the base material constituting the tape was changed to Kraft paper.

(Conventional Example 1) An aluminum electrolytic capacitor was manufactured in the same manner as in Example 1 using a conventional adhesive tape such as polypropylene.

(Conventional Example 2) An aluminum electrolytic capacitor was manufactured in the same manner as in Example 1 using a conventional one without tape coating.

When the aluminum electrolytic capacitors of Examples 1 and 2 and Conventional Examples 1 and 2 were manufactured, the occurrence rates of short-circuit defects were as shown in Table 1. Examples 1 and 2 and conventional example
FIG. 2 shows the change in leakage current when the high-temperature load test at 125 ° C. for 1000 hours was performed on the aluminum electrolytic capacitors 1 and 2 described above.

In addition, the base material of the tape is not limited to the manila paper of Example 1 and the kraft paper of Example 2; The same result was confirmed.

As is clear from Table 1 and FIG. 2, Examples 1 and 2 can significantly reduce the occurrence rate of short-circuit defects in both the winding step and the assembling / completion step. It shows very stable characteristics in the test.

As is clear from the description of the above embodiment, the aluminum electrolytic capacitor of the present invention covers the entire front and back surfaces of the cut portions at both ends in the length direction of the anode foil and the cathode foil with the tape. The tape that has been cut, at the cut portion at both ends of the electrode foil, and make an interval between the electrode foil opposite to this,
The winding stress generated between the cutting burrs of the electrode foil and the electrode foil of the counter electrode can be absorbed, thereby ensuring that the cutting burrs break through the separator paper and contact the anode foil and the cathode foil. Short-circuit failure does not occur.

Further, since the tape is formed by applying an adhesive that allows the driving electrolyte to penetrate over the entire surface of one side of the substrate made of a material that allows the driving electrolyte to permeate, the tape is used to form an anode foil and a cathode foil. Even when covering the entire front and back surfaces of the cut portions at both ends in the length direction, at the time of impregnation of the driving electrolyte, this driving electrolyte will be impregnated at the time of the cutting,
Therefore, since the dielectric oxide film of the anode foil is repaired with the driving electrolyte, the characteristics are not deteriorated.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a positional relationship of members constituting a capacitor element of an aluminum electrolytic capacitor according to an embodiment of the present invention, FIG. 2 is a leakage current characteristic diagram during a high-temperature load test, and FIG.
Fig. 4 is a longitudinal sectional view of a conventional aluminum electrolytic capacitor, Fig. 4 is a perspective view showing a state where an electrode foil is cut by a required length from a roll foil, and Fig. 5 is a diagram showing a capacitor element of the conventional aluminum electrolytic capacitor. FIG. 6 is an exploded perspective view showing the positional relationship of the constituent members, and FIG. 6 is a sectional view showing a state of cutting burrs at a cutting portion of the electrode foil. 1 ... Anode foil, 2 ... Cathode foil, 3 ... Separator paper, 4
…… Capacitor element, 11 …… Tape.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiaki Okada 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 8920 (JP, Y1) (58) Field surveyed (Int. Cl. ⁶ , DB name) H01G 9/02

Claims (3)

(57) [Claims] 1. A capacitor element which is formed by winding a separator paper between an anode foil and a cathode foil, and comprising a cutting element at both ends in the longitudinal direction of the anode foil and the cathode foil. An aluminum electrolytic capacitor formed by coating the entire surface with a tape, and applying an adhesive that penetrates the driving electrolyte to the entire surface of one side of a substrate made of a material that penetrates the driving electrolyte. 2. The aluminum electrolytic capacitor according to claim 1, wherein the base material constituting the tape is a separator paper for an aluminum electrolytic capacitor. 3. The aluminum electrolytic capacitor according to claim 1, wherein the base material constituting the tape is any one of manila paper, kraft paper, esparto paper, and red linen paper, or paper obtained by mixing them. .