JP4867666B2 - Solid electrolytic capacitor - Google Patents

Description

  The present invention relates to an electrolytic capacitor using a solid 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. 10 is a cutaway perspective view of a conventional solid electrolytic capacitor. In FIG. 10, the surface of an aluminum foil etched as an anode foil 21 is provided with a dielectric film, and the aluminum foil etched as a cathode foil 22 is used. 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 provided with a solid electrolyte 25 as an electrolyte and accommodated in a case 29. The solid 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. Is configured.

  When considering a high breakdown voltage as a solid electrolytic capacitor, an aluminum foil which is an inexpensive general-purpose material is preferable as an electrode to be used. 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 chemical conversion foil formed before slitting, and as a solid electrolytic capacitor is reduced in size. There was a problem that the leakage current would increase.

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

In order to achieve this object, the present invention winds a valve metal wire in a spiral shape, uses the wound one end as an anode portion, and establishes a spiral shape center between adjacent valve metals excluding the anode portion. An anode body having a connecting portion provided radially from the portion, a dielectric film provided on the surface of the anode body other than the anode part, a solid electrolyte provided on the surface of the dielectric film, and a surface of the solid electrolyte A capacitor element wound in a spiral shape made of a current collector provided on the substrate, a plurality of capacitor elements stacked to form a laminate, an anode terminal electrically connected to the anode portion of the laminate, and the capacitor A cathode terminal electrically connected to the current collector of the device, a bottomed cylindrical case for housing the laminate provided with the anode terminal and the cathode terminal, and sealing the opening of the case Insert the anode terminal and the cathode terminal Than ash is and a sealing body for.

  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 This has the effect of being able to suppress the increase of.

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

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

(Embodiment 1)
In particular, the first embodiment will be described with reference to the first embodiment.

  FIG. 1 is a perspective view of a solid electrolytic capacitor in Embodiment 1, FIGS. 2 to 4 are sectional views thereof, and FIG. 5 is a perspective view of an anode body.

  1 to 3, an etched aluminum wire is used as the anode body 1, and a dielectric film 2 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 2 may be performed after the dielectric film 2 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. 2 may be formed.

  A solid electrolyte 3 is formed on the surface of the dielectric film 2. As the solid electrolyte 3, a conductive polymer such as polypyrrole, polyaniline, polythiophene or the like can be used alone or in combination. As a forming method, conventional techniques such as chemical polymerization and electrolytic polymerization can be used.

  A current collector 4 is provided on the surface of the solid electrolyte 3. As the current collector 4, a laminate of a carbon layer and a silver paste can be used. In this way, the cathode portion 9 composed of the solid electrolyte 3 and the current collector 4 is formed.

  The capacitor element 5 is formed by the above configuration. A plurality of capacitor elements 5 are stacked via the current collector 4 (three in the first embodiment) to form a stacked body 6. The number of stacked capacitor elements 5 can be set as appropriate.

  The anode parts of the capacitor elements 5 of the multilayer body 6 are connected by anode terminals 7, respectively. For this connection, resistance welding, laser welding, silver adhesive, or the like can be used.

  Similarly, a cathode terminal 8 is provided in the cathode portion 9. The cathode terminal 8 may be connected to the cathode portion 9 of any one of the capacitor elements 5 as shown in FIG. 2, for example, the center of the lower surface of the multilayer body 6. However, in consideration of ESR, FIG. As shown, it is preferable to connect to the cathode part 9 of each capacitor element 5 or to connect to the cathode part 9 of each capacitor element 5 by penetrating the central part of the laminate as shown in FIG. By doing so, the connection between the cathode portion 9 and the cathode terminal 8 is ensured and a plurality of current flow paths are provided, which is effective in reducing ESR.

  The capacitor element 5 to which the anode terminal 7 and the cathode terminal 8 are connected is housed in an aluminum case 10, and the opening of the aluminum case 10 is sealed with a sealing rubber 11.

  By sealing with the sealing rubber 11 in this way, it is not necessary to consider the influence of the humidity of the external environment on the capacitor element 5. That is, when storing this solid electrolytic capacitor, there is an effect that it is not necessary to take a moisture-proof measure.

  Note that the anode body 1 may be simply wound in a spiral shape as shown in FIG. 5, but at least the adjacent valve metal wire after being wound as shown in FIG. 6 (a). You may provide a connection part between.

  FIG. 6A 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 put 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.

  Moreover, as shown in FIG.6 (b), even if it uses so that it may have two derivation | leading-out parts 18, it may use so that the folded part of the valve metal wire folded in half may become the center part of a spiral. Good. This shape and the connecting portion 15 can be used either alone or in combination, and when combined, the effect is further reduced in ESR and ESL.

(Embodiment 2)
The invention described in other embodiments is described with reference to the second embodiment.

  The second embodiment is different from the first embodiment in that it has a pair of anode terminals. Hereinafter, it demonstrates using drawing.

  FIG. 7 is a cross-sectional view of the solid electrolytic capacitor according to the second embodiment, and the multilayer body 12 is configured by alternately laminating a plurality of capacitor elements 5 in directions in which the anode portions oppose each other. A pair of anode terminals 13 are electrically connected to the anode portions in opposite directions. Further, the cathode terminal 8 is connected to the cathode portion 9 of each capacitor element 5 by penetrating the central portion of the multilayer body 12.

  The contents other than the above are the same as in the first embodiment.

  With the above configuration, a so-called three-terminal capacitor having two anode terminals and one cathode terminal can be formed.

(Embodiment 3)
The invention described in another embodiment is described with reference to the third embodiment .

  The third embodiment is different from the second embodiment in the shape of the cathode terminal, and a so-called four-terminal capacitor is formed by changing the shape of the cathode terminal.

  FIG. 8A is a perspective view of the solid electrolytic capacitor according to the third embodiment, and FIG. 8B is a cross-sectional view taken along line AA. The cathode terminal 14 is branched in the mounting surface direction so that the pair of cathode terminals 14 are exposed on the mounting surface substantially perpendicular to the direction connecting the pair of anode terminals 13 on the mounting surface. In FIG. 8, the cathode terminal 14 is provided so as to penetrate the central portion of the multilayer body 6, but may be connected to the lower surface of the multilayer body 6.

  Moreover, as another form of a cathode terminal, as shown in FIG. 9, what is provided separately without branching is mentioned. FIG. 9 is a cross-sectional view of the solid electrolytic capacitor according to the third embodiment. In FIG. 9, the cathode terminal 14 is provided on the peripheral surface of the multilayer body 6. At this time, silver adhesive 16 or the like can be used to connect the cathode portion 9 and the cathode terminal 14 of the laminate 6. Also in the structure of the cathode terminal as described above, the cathode terminal can be arranged so as to be arranged in a direction substantially perpendicular to the direction connecting the pair of anode terminals.

  In the embodiment described above, a laminate in which a plurality of capacitor elements are laminated is used. However, the present invention is not limited to this, and a capacitor element can be used as a single layer.

  Moreover, although each capacitor | condenser element of a laminated body is laminated | stacked via the electrical power collector, you may laminate | stack via a solid electrolyte. In that case, it is desirable to form a current collector on the outermost peripheral surface of the laminate in order to reduce the contact resistance when connecting to the cathode terminal.

  Further, although the radial type capacitor has been described as a solid electrolytic capacitor, the surface mounting type having a configuration in which an insulating plate (not shown) is in contact with the sealing rubber side of the aluminum case 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 solid electrolytic capacitor in Embodiment 1 of this invention Sectional view Sectional view Sectional view The perspective view of the anode body in Embodiment 1 of this invention (A), (b) is the same perspective view, respectively Sectional drawing of the solid electrolytic capacitor in Embodiment 2 of this invention (A) Perspective view of a solid electrolytic capacitor in Embodiment 3 of the present invention, (b) The same sectional view along the AA line Sectional view Cutaway perspective view of a conventional solid electrolytic capacitor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Anode body 2 Dielectric film 3 Solid electrolyte 4 Current collector 5 Capacitor element 6, 12 Laminated body 7, 13 Anode terminal 8, 14 Cathode terminal 9 Cathode part 10 Aluminum case 11 Sealing rubber 15 Connection part 16 Silver adhesive 18 Derivation Part

Claims (1)

A valve metal wire is wound in a spiral shape, and one end of the wound metal wire is used as an anode portion, and an anode having a connecting portion provided radially from a spiral-shaped central portion between adjacent valve metals excluding the anode portion. A body, a dielectric film provided on the surface of the anode body other than the anode portion, a solid electrolyte provided on the surface of the dielectric film, and a current collector provided on the surface of the solid electrolyte. A plurality of the capacitor elements rotated, a plurality of the capacitor elements are laminated to form a laminate, and an anode terminal electrically connected to the anode portion of the laminate and the current collector of the capacitor element are electrically connected A cathode terminal, a case with a bottomed tube that houses the anode terminal and a laminate provided with the cathode terminal, a sealing body that seals the opening of the case and inserts the anode terminal and the cathode terminal; solid body electrolytic capacitor having a Support.

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