JP2008177201A - Solid electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a leakage current while miniaturizing a solid electrolytic capacitor. <P>SOLUTION: The solid electrolytic capacitor comprises: an anode body 1; an anode lead 2 connected to the anode body 1; a dielectric film 3 provided on the surface of the anode body 1; an anode body 5 arranged opposingly via the anode body 1 where the dielectric film 3 is provided and a separator 4; a capacitor element 7 made of a cathode lead 6 connected to the cathode body 5; an electrolyte for drive stored in a case 8 along with the capacitor element 7; and a sealing element 9 that seals the opening of the case 8 and inserts the anode lead 2 and the cathode lead 6. The anode body 1 and the cathode body 5 are formed by winding a valve metal wire. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrolytic capacitor using a driving electrolyte.

  2. Description of the Related Art In recent years, with high performance and miniaturization of electronic equipment, a capacitor having a high withstand voltage and a small size has been demanded.

  FIG. 9 is a cutaway perspective view of a conventional electrolytic capacitor. In FIG. 9, the surface of an etched aluminum foil as the anode foil 21 is provided with a dielectric film, and the etched aluminum foil is used as the cathode foil 22. The anode foil 21 has an anode lead 27 and a cathode foil 22. Are provided with a cathode lead 28, and a capacitor element 24 is formed by winding a separator 23 between the anode foil 21 and the cathode foil 22. The capacitor element 24 is impregnated with a driving electrolytic solution and accommodated in a case 29. The electrolytic capacitor is provided with a sealing body 30 for inserting the anode lead 27 and the cathode lead 28 and sealing the opening of the case 29. It is configured.

  When considering high breakdown voltage as an electrolytic capacitor, an aluminum foil that is an inexpensive general-purpose material is preferable as an electrode to be used, and when realizing miniaturization at the same time, it is necessary to narrow the width of the aluminum foil as an electrode.

  In general, this electrode has a wide etching foil (hereinafter referred to as chemical conversion foil) formed with a dielectric film cut to a desired width with a slitter, so that the aluminum base is exposed from the end face. . Therefore, a dielectric film is formed on the end face by aging treatment.

Patent Document 1 is known as prior art document information related to the invention of the present application.
Japanese Patent Laid-Open No. 06-275476

  As the electrode width is reduced for miniaturization, the ratio of the area of the end face to the apparent area of the electrode increases, and the adverse effect of the dielectric film on the end face formed by aging becomes prominent. That is, normally, the dielectric film formed by aging is not dense in comparison with the dielectric film of the conversion foil formed before slitting, so that leakage as an electrolytic capacitor as the size is reduced. There was a problem that the current increased.

  Therefore, an object of the present invention is to reduce leakage current while realizing miniaturization.

  To achieve this object, the present invention provides an anode body, an anode lead connected to the anode body, a dielectric film provided on the surface of the anode body, and an anode body provided with the dielectric film, Capacitor element comprising cathode body arranged opposite to each other via separator, cathode lead connected to this cathode body, driving electrolyte contained in case together with this capacitor element, and opening of said case are sealed And a sealing body through which the anode lead and the cathode lead are inserted, and the anode body and the cathode body are configured by winding a valve metal wire.

  According to the present invention, since there is no exposure of the metal substrate on the electrode end face by the slitter, it is not necessary to form a dielectric film by aging on the exposed metal element as in the prior art, and the leakage current caused by this dielectric film Has the effect of suppressing the increase in

  In addition, since the conventional aging process can be omitted, the process can be simplified and the productivity can be improved.

  Hereinafter, an electrolytic capacitor of the present invention will be described with reference to an embodiment and drawings.

  FIG. 1 is a perspective view of an electrolytic capacitor according to an embodiment, and FIG. 2 is a cross-sectional view thereof.

  1 and 2, an etched aluminum wire is used as the anode body 1, and a dielectric film 3 formed on the surface thereof is wound in a spiral shape. The anode body 1 may be wound with a pre-etched aluminum wire or may be etched after being wound.

  Similarly, the formation of the dielectric film 3 may be performed after the dielectric film 3 is formed on the surface of the etched aluminum wire, or may be wound after the aluminum wire is wound, and then the dielectric film is formed. 3 may be formed.

  On the other hand, the cathode body 5 is also wound with an etched aluminum wire in a spiral shape. The anode body 1 may be wound with a pre-etched aluminum wire or may be etched after being wound.

  And the anode body 1 and the cathode body 5 are laminated | stacked alternately with the separator 4 interposed. The number of layers at this time can be set as appropriate.

  An anode lead 2 is connected to each anode body 1, and a cathode lead 6 is connected to each cathode body 5. At this time, all the anode bodies 1 may be once connected together and then connected to the anode lead 2. Examples of the connection method include resistance welding and laser welding.

  The capacitor element 7 is configured by the above configuration.

  The capacitor element 7 is impregnated with a driving electrolyte and accommodated in an aluminum case 8.

  The opening of the aluminum case 8 is sealed with a sealing body 9 through which the anode lead 2 and the cathode lead 6 are inserted.

  Note that the anode body 1 (cathode body 5) may be simply wound in a spiral shape as shown in FIG. 3, but at least adjacent valves after winding as shown in FIG. You may provide a connection part between metal wires.

  FIG. 4 is a perspective view of the anode body, in which a connecting portion 15 is provided between adjacent valve metal wires. In this case, it is possible to suppress a decrease in capacity particularly in the high frequency region. That is, by providing the connecting portion 15, a plurality of current flow paths can be provided, which makes it easier to take in and out electrons as a capacitor in a high frequency region. As a result, it is possible to suppress a decrease in capacity in the high frequency region.

  As a method of providing the connecting portion 15, adjacent valve metal wires may be connected by resistance welding, laser welding, or the like, or a new valve metal wire is provided and adjacent via this new valve metal wire. The valve metal wires to be connected may be connected.

  In particular, from the viewpoint of suppressing a decrease in capacity in the high frequency region, it is desirable to provide a plurality of connecting portions radially from the spiral central portion. Moreover, what is necessary is just to provide the connection part 15 in multiple places in the outer peripheral surface, when an anode body is only a coil shape.

  The step of providing the connecting portion 15 is desirably performed after the etching process. This is because the connecting portion 15 may be melted and removed from the anode body 1 by the etching process.

  Further, as shown in FIG. 5, as the shape of the anode body, if the spiral shape 11 is formed so that there are two lead-out portions, that is, the folded portion of the folded valve metal wire is at the center of the spiral. When the winding is performed in such a manner, there are two lead-out portions 13, and when each lead-out portion 13 is connected to the anode lead, a three-terminal capacitor can be manufactured.

  In addition, in the same manner for the cathode body 5, a four-terminal capacitor having two anode leads and two cathode leads can be manufactured.

  6 is a perspective view of a four-terminal capacitor using the spiral body 11 shown in FIG. 5 as an anode body and a cathode body, FIG. 7 is a sectional view taken along the line AA, and FIG. 8 is a sectional view taken along the line BB. It is sectional drawing.

  As described above, the capacitor having a plurality of lead-out paths for both the anode body and the cathode body is particularly effective in reducing ESR and ESL. Further, by using a high-conductivity driving electrolyte, the capacitor is further improved. The effect is improved.

  In the above-described embodiment, a plurality of laminated anode bodies and cathode bodies are used. However, the present invention is not limited to this, and one set of anode bodies and cathode bodies can be used.

  Although the electrolytic capacitor is described as a radial type, an insulating plate (not shown) is brought into contact with the case from the side of the case sealing body, and the anode and cathode leads are bent along the bottom surface of the insulating plate. The surface mounted type having the configuration has the same function and effect.

  The present invention has a feature of using a wound metal valve wire as an anode body, and is particularly useful for various electronic devices that are small and require low leakage current characteristics.

The perspective view of the electrolytic capacitor in one embodiment of the present invention Cross section The perspective view of the anode body in one embodiment of this invention Same perspective view Same perspective view The perspective view of the electrolytic capacitor in one embodiment of the present invention The same sectional view at A-A Sectional view along line B-B Cutaway perspective view of a conventional electrolytic capacitor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Anode body 2 Anode lead 3 Dielectric film 4 Separator 5 Cathode body 6 Cathode lead 7 Capacitor element 8 Aluminum case 9 Sealing body 11 Spiral shape 13 Lead-out part 15 Connection part

Claims (4)

An anode body, an anode lead connected to the anode body, a dielectric film provided on the surface of the anode body, an anode body provided with the dielectric film, and a cathode body disposed opposite to each other via a separator, A capacitor element comprising a cathode lead connected to the cathode body, a driving electrolyte contained in the case together with the capacitor element, and a seal for sealing the opening of the case and inserting the anode lead and the cathode lead An electrolytic capacitor in which the anode body and the cathode body are formed by winding a valve metal wire. An anode body having a dielectric film on its surface; a laminate in which cathode bodies are alternately arranged opposite to each other via a separator; an anode lead electrically connected to the anode body of the laminate; and the laminate A capacitor element comprising a cathode lead electrically connected to the cathode body of the body, a driving electrolyte contained in the case together with the capacitor element, and sealing the opening of the case and the anode lead and the cathode An electrolytic capacitor having a sealing body through which a lead is inserted, wherein the anode body and the cathode body are formed by winding a valve metal wire. The electrolytic capacitor according to claim 1, wherein the anode body has a spiral shape. The electrolytic capacitor according to claim 3, wherein the spiral anode body is provided with a connecting portion between at least adjacent valve metal wires.

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