JP2000164467A - Electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent each burr of a cathod foil and an anode foil from biting in separators, which are positioned adjacent to each electrode foil, by a method wherein the end parts in the widthwise directions of the electrode foils are abutted on the striped parts of a prescribed width of both ends, which are not formed with emboss parts, of the separators. SOLUTION: The striped parts of a prescribed width of both ends in the widthwise directions of separators 20 and 30 are thin non-processed parts 23 and 24 and the central parts in the widthwise directions of the separators 20 and 30 are thick striped emboss parts 10. Electrode fails 4 and 5 are first abutted on the thick striped emboss parts 10 of the central parts of the widthwise directions of the separators 20 and 30 and by this abutment of the foils 4 and 5 on these emboss parts 10, a constant distance is kept between the thickness directions of the foils 4 and 5 and separators 20 and 30. Burrs 7 formed on the cut parts of the end parts in each widthwise direction of the foils 4 and 5 in this state are arranged abuttingly on or in close proximity to the striped parts of the prescribed width of both ends, which are not formed with the emboss parts 10, in the widthwise directions of the separators 20 and 30, that is, the thin non-processed parts 23 and 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic capacitor having an improved structure of a separator used for a capacitor element.

[0002]

2. Description of the Related Art In an electrolytic capacitor, an aluminum foil for an electrode is electrochemically roughened to increase the surface area, and a dielectric oxide film is formed on the surface by anodic oxidation.

As shown in FIG. 2, a roll 12 of this kind of aluminum foil 8 processed for an electrode foil of an electrolytic capacitor is used.
Is cut into a plurality of pieces at a predetermined width by the roll cutter 9,
It is formed on the roll 13 of the electrode foil 14 shown in FIG. The roll cutter 9 is composed of a plurality of narrow rotating blades at predetermined intervals on the rotating shaft 18.
The upper blade 19 is coaxially fixed and the plurality of rotary blades 19 project in a brim-like shape, and the plurality of roller-shaped rotary blades 22 having a wide width are fixed to the rotary shaft 21 coaxially. ) Is formed in combination with a lower blade having grooves formed at predetermined intervals at positions where the lower blades are fitted.

In the roll cutter 9, the tip of a rotating blade 19 (upper blade) projecting like a brim fits into a groove formed between the wide roller-shaped rotating blades 22 (lower blade). As a result, the lower blade portion formed on the end surface of each roller-shaped rotary blade 22 rubs against the tip of the rotary blade 19 (upper blade) to cut the aluminum foil 8. When the aluminum foil 8 is cut, a burr 17 is formed at the cut portion so as to protrude, and the aluminum foil 8 is wound so that the burr 17 protrudes to the outer peripheral side.

At present, a capacitor element is formed using a roll 13 of an electrode foil 14 having burrs 17 formed on a cut portion. This type of capacitor element is shown in FIGS.
Shown in 4A and 4B, lead terminals 25 are connected to the cathode foil 4 and the anode foil 5, respectively. Between the cathode foil 4 and the anode foil 5, the separators 2 and 3 are interposed and wound to form a capacitor element 11. The capacitor element 11 is wrapped around the periphery with a tape 16.

The cathode foil 4 and the anode foil 5 used for manufacturing the capacitor element 11 have the same structure as the roll 13 of the electrode foil 14 wound so that the burrs 17 project outward. I have. Therefore, the cathode foil 4 and the anode foil 5 of the manufactured capacitor element 11 are also wound so that the burrs 17 project to the outer peripheral side.

[0007]

In the conventional capacitor element, since each burr of the cathode foil and the anode foil is wound so as to protrude to the outer peripheral side, each burr is formed on the outer periphery of each electrode foil. In some cases, it breaks into the adjacent separator and breaks through.

[0008] Since the burrs of the electrode foil penetrate into the separator and break through, the withstand voltage is significantly reduced, and short-circuits occur due to the application of an abnormal voltage such as an overvoltage.
Damage accidents are more likely to occur.

The present invention solves the above-mentioned drawbacks of the electrolytic capacitor and realizes a separator structure in which burrs of each of the cathode foil and the anode foil do not bite into the separator located adjacent to each electrode foil. The present invention is to provide an electrolytic capacitor that prevents damage accidents due to short-circuit by applying an abnormal voltage such as

[0010]

In the electrolytic capacitor of the present invention, a separator having a band-shaped embossed portion formed in the center portion is wound together with electrode foils of both electrodes, and a predetermined width of both ends of the separator having no embossed portion is formed. The present invention is characterized in that a capacitor element having an end portion in the width direction of the electrode foil in contact with the strip portion is provided.

[0011]

FIG. 1 (a) shows an embodiment of the present invention.
(B). In FIGS. 1A and 1B, the same reference numerals as those in FIGS. 4A and 4B denote the same components.

In FIGS. 1A and 1B, the cathode foil 4
A lead terminal 15 is connected to each of the anode foils 5. A separator 2 is provided between the cathode foil 4 and the anode foil 5.
0 and 30 are interposed and wound to form capacitor element 1.

The electrode foils such as the cathode foil 4 and the anode foil 5 forming the capacitor element 1 (hereinafter, the cathode foil 4 and the anode foil 5 will be referred to as the electrode foils 4 and 5) are each in the width direction. Is wound so that a burr 7 formed at a cut portion at the end of the outer side protrudes toward the outer peripheral side. The separators 20 and 30 located adjacent to the electrode foils 4 and 5 are located at the center while leaving a predetermined width at a portion where both end portions in the width direction of the electrode foils 4 and 5 (cut portions of the electrode foils 4 and 5) are in contact. The separator is embossed on the part, and the separator is in the vicinity of the part where both ends in the width direction of the electrode foils 4 and 5 are in contact.
Band-shaped portions of a predetermined width at both ends of each of 20, 30 are unprocessed portions 23,
24, and the central portion leaving the unprocessed portions 23 and 24 is the band-shaped embossed portion 10.

In this embodiment, as a material of the separators 20 and 30, a material having a strength not to be damaged by embossing and having a sufficient pressure resistance is used. Was adopted. Further, since the separators 20 and 30 are embossed only in the central portion in the width direction, the withstand voltage is slightly lower than the non-processed portions 23 and 24 in the embossed portion 10 formed in a band shape in the central portion, but on the other hand, ESR is reduced due to improved ion permeability.

The strip portions having a predetermined width at both ends in the width direction are thin non-processed portions 23, 24.
Withstand voltage can be obtained sufficiently. Thus, the separators 20, 30
The strip-shaped portions of a predetermined width at both ends in the width direction are thin unprocessed portions 23 and 24, and the center portion is a thick strip-shaped embossed portion.
It has a configuration of 10.

The electrode foils 4, 5 first come into contact with the thick band-shaped embossed portion 10 at the central portion in the width direction of the separators 20, 30. , 5 and the separators 20 and 30 are kept at a constant distance in the thickness direction. In this state, the burrs 7 formed at the cut portions at the ends in the width direction of the electrode foils 4 and 5 are removed from the embossed portions 10.
Are arranged in contact with or in close proximity to the strip-shaped portions of a predetermined width at both ends in the width direction of the separators 20 and 30 in which the non-processed portions 23 and 24 are thin.

The contact between the electrode foils 4 and 5 and the thick embossed portions 10 of the separators 20 and 30 keeps a certain distance in the thickness direction between the electrode foils 4 and 5 and the separators 20 and 30. Even if the burrs 7 formed at the cut portions of the widthwise ends of the electrode foils 4 and 5 are wound so as to protrude to the outer peripheral side of the capacitor element 1, Even if the non-processed portions 23 and 24 of the strips having a predetermined width at both ends of the separators 20 and 30 positioned adjacent to each other, the non-processed portions 23 and 24 are not strongly pressed. However, since they do not bite into the inner peripheral surfaces of the separators 20 and 30, damage to the separators 20 and 30 by the burrs 7 hardly occurs.

The embossed portions 10 of the separators 20 and 30 in contact with the electrode foils 4 and 5 have a somewhat lower withstand voltage than the non-processed portions 23 and 24, however, a certain amount of the separator in the thickness direction of the embossed process. By increasing the distance between the electrodes and maintaining the overall withstand voltage, and increasing the ion permeability of the separator by embossing, the ES
R can be reduced. On the other hand, burrs 7 formed in the cut portions of the electrode foils 4 and 5 are arranged at the ends in the width direction of the separators 20 and 30 in contact with or close to each other. Since the parts 23 and 24 have sufficient withstand voltage.

[0019]

According to the present invention, the internal structure of the capacitor element is improved, and only the center portion in the width direction of the separator is embossed in a band shape, and the embossed thickness is formed in the center portion in a band shape. In the strip-shaped embossed portion of the separator that is in contact with the separator, a constant distance is maintained in the thickness direction. Therefore, the burr generated at the time of cutting each of the two electrode foils does not bite into the separator, thereby preventing the separator from being damaged. Moreover, the capacitor element is provided with burrs 7 formed at each cut portion of the electrode foil in contact with or close to each other so that the reduction of the withstand voltage due to the embossing of the separator is not affected. The band-shaped part of the predetermined width remains the unprocessed part,
The withstand voltage is sufficient.

Therefore, in the present invention, the capacitor element is
ESR is reduced by improving the ion permeability of the separator by embossing, and the withstand voltage is sufficiently reduced where it is needed without affecting the decrease in withstand voltage by the embossing of the separator. Its practical value is great, for example, it is difficult to cause breakage accidents due to short-circuit of the electrolytic capacitor due to application of abnormal voltage such as overvoltage.

[Brief description of the drawings]

FIG. 1A is a perspective view of a capacitor element according to an embodiment of the present invention. (B) is a schematic diagram showing an internal structure of a capacitor element according to an embodiment of the present invention.

FIG. 2 is a perspective view of a step of cutting a roll of aluminum foil into a plurality of rolls.

FIG. 3 is a perspective view of a roll of cut electrode foil.

FIG. 4A is a perspective view of a conventional capacitor element. (B) is a schematic diagram showing an internal structure of a conventional capacitor element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Separator 3 Separator 4 Cathode foil 5 Anode foil 7 Burr 8 Aluminum foil 9 Roll cutter 10 Emboss part 11 Capacitor element 12 Roll 13 Roll 14 Electrode foil 15 Lead terminal 16 Anti-winding tape 17 Burr 18 Rotary axis 19 Rotary blade 20 Separator 21 Rotary shaft 22 Rotary blade 23 No processing part 24 No processing part 25 Lead terminal 26 Roller 27 Roller 28 Roller 30 Separator

Claims (1)

[Claims] 1. A separator having a band-shaped embossed portion formed at a center portion thereof is wound together with electrode foils of both electrodes, and end portions in a width direction of the electrode foil are formed at predetermined widths of both ends of the separator having no embossed portion. An electrolytic capacitor provided with a capacitor element contacted with a.