JP5035999B2 - Solid electrolytic capacitor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a surface mount type solid electrolytic capacitor for a power supply line and a manufacturing method thereof, and more particularly to a solid electrolytic capacitor connected to a CPU and suitable for a decoupling circuit for a stabilized power supply and a manufacturing method thereof.

  3A and 3B are views showing a conventional solid electrolytic capacitor, FIG. 3A is a sectional view showing the whole, and FIG. 3B is a sectional view of the solid electrolytic capacitor element.

  Conventionally, as shown in FIG. 3B, a solid electrolytic capacitor element has a foil-like or plate-like valve-acting metal anode body 15 having an enlarged surface, on which a dielectric film 16 is formed. The end portion 11 is separated by an insulating resin 13, and a solid electrolyte layer composed of a conductive polymer layer 17 is formed on the dielectric film 16 in the central portion. Thereafter, the graphite 4 and the silver paste 5 are applied to the cathode portion. Is formed.

  Next, as shown in FIG. 3A, a metal strip 14 of copper or copper alloy is welded to the anode body end portion 11 of each solid electrolytic capacitor element to form an anode portion, and these are laminated. 3A is a form in which the rectangular plate-shaped solid electrolytic capacitor elements of FIG. 3B are stacked in three layers, and a solid electrolytic capacitor element laminate 200 is formed. At this time, the anode part is connected using resistance welding and laser welding, and the cathode part 12 is connected using the conductive paste 25. The solid electrolytic capacitor element laminate 200 is disposed inside a box-shaped molded resin case 22 having an anode terminal 20 and a cathode terminal 21 formed from a lead frame on the bottom surface, and an upper surface of the anode terminal 20. The lower surface of the metal strip 14 welded to the anode body end portion 11 at the lower end is connected with the conductive paste 25, and the cathode portion 12 at the lower end and the cathode terminal 21 are connected with the conductive paste 25. . Here, the anode terminal 20 and the cathode terminal 21 have a flat plate shape and are formed in the same plane as the substrate mounting surface. The molded resin case 22 is formed by insert molding so as to fill a gap between the anode terminal 20 and the cathode terminal 21 and mechanically connect both terminals, and to have a side wall around the solid electrolytic capacitor element. A solid electrolytic capacitor 100 is obtained by covering the side wall with a box-shaped lid 23 and enclosing the solid electrolytic capacitor element laminate 200 (see, for example, Patent Document 1).

  When the molded resin case 22 that is the outer shape of the solid electrolytic capacitor is miniaturized in the length direction, a method of shortening the metal strip 14 or a method of shortening the cathode portion 12 that is a capacity appearance portion, Alternatively, there is a method of shortening the width of the insulating resin 13.

  However, in the case of the method of shortening the metal strip piece 14, there is a disadvantage that the connection area is reduced and the connection strength is lowered when the anode terminal 20 and the metal strip piece 14 are connected by the conductive paste 25.

  In addition, there is a method of shortening the cathode portion 12 which is a capacity appearing portion. However, the capacity is reduced and the essence is lost, or the method of shortening the width of the insulating resin 13 is used as the conductive polymer layer 17. When the insulating resin 13 is formed, the width of the insulating resin 13 is short, so that the conductive polymer layer may enter the anode side and cause a short circuit.

JP 2006-128247 A

  An object of the present invention is to provide a solid electrolytic capacitor and a method for manufacturing the same that can reduce the outer shape without reducing the capacitance.

  According to the present invention, a plate-shaped solid electrolytic capacitor element having an anode portion at an end portion and a cathode portion at a central portion or a solid electrolytic capacitor element laminate formed by laminating the solid electrolytic capacitor element, and the anode portion In a solid electrolytic capacitor comprising an anode terminal connected to the cathode part and a cathode terminal connected to the cathode part, the anode part has a structure in which the end of the anode body to which the metal strip piece is connected is folded. A characteristic solid electrolytic capacitor can be obtained.

  In addition, the anode terminal and the cathode terminal are plate-like, formed on the same plane as the substrate mounting surface, and has a bottom surface portion that fills the gap between the anode terminal and the cathode terminal and mechanically connects them, A resin case having a side wall orthogonal to the plane is formed, and the anode terminal and the cathode terminal are exposed on the inner bottom surface of the resin case, and the anode part of the solid electrolytic capacitor element or the solid electrolytic capacitor element laminate A solid electrolytic capacitor characterized by being connected to the cathode portion can be obtained.

  Further, according to the present invention, after forming a dielectric film on an anode body made of an enlarged valve action metal plate or foil, the anode body end portion is separated by an insulating resin to provide an anode portion and a central portion Forming a solid electrolyte layer and a conductive material layer on the dielectric film and providing a cathode portion; connecting a metal strip piece to an end of the anode body; and an anode to which the metal strip piece is connected A solid electrolytic capacitor comprising: a step of producing a solid electrolytic capacitor element by folding a body end portion; a step of connecting an anode terminal to the metal strip; and a step of connecting a cathode terminal to the cathode portion. The manufacturing method can be obtained.

  Further, according to the present invention, after forming a dielectric film on an anode body made of an enlarged valve action metal plate or foil, the anode body end portion is separated by an insulating resin to provide an anode portion and a central portion Forming a solid electrolyte layer and a conductive material layer on the dielectric film and providing a cathode portion; connecting a metal strip piece to an end of the anode body; and an anode to which the metal strip piece is connected A step of producing a solid electrolytic capacitor element by folding the body end, a step of producing a solid electrolytic capacitor element laminate by laminating the solid electrolytic capacitor elements and connecting anode portions and cathode portions to each other, and the anode A solid electrolytic capacitor manufacturing method comprising a step of connecting an anode terminal to a metal strip piece of the portion and a step of connecting a cathode terminal to the cathode portion.

  Furthermore, the step of arranging the anode terminal and the cathode terminal on the bottom surface on the same plane and forming a resin case having a bottom surface portion and a side wall portion by an insert molding method, and the solid electrolytic capacitor element or the solid electrolytic capacitor element laminated body Including a step of connecting the anode terminal to the metal strip piece of the anode portion, a step of connecting the cathode terminal to the cathode portion, and a step of connecting a lid covering the upper side of the resin case to the resin case. Good.

  According to the present invention, the end of the anode body to which the metal strip pieces are connected is folded back to form an anode part, which is connected to the anode terminal, thereby maintaining the connection area and capacity between the anode body and the anode terminal and maintaining the capacity. The molded resin case can be reduced in size. That is, according to the present invention, it is possible to provide a solid electrolytic capacitor that is excellent in connection reliability and reduced in size and a method for manufacturing the same.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a solid electrolytic capacitor according to an embodiment of the present invention. A dielectric film is formed by an electrochemical method or the like on the surface of the anode body obtained by expanding the valve action metal containing any of Al, Ti, Ta, and Nb by etching or the like. Next, the anode body end portion is separated by the insulating resin 13 to provide a portion to be the anode portion and form a solid electrolyte layer made of a conductive polymer layer on the surface of the dielectric film at the center portion, A graphite layer and a silver paste layer are sequentially formed to form the cathode portion 12. Next, after connecting the metal strip piece 14 to the end portion of the anode body by resistance welding or the like, the anode body end portion is folded back, and the anode portion including the folded anode body end portion and the metal strip piece 14 is used as solid electrolysis. A capacitor element is produced. If necessary, the solid electrolytic capacitor elements are stacked, the anode portions are connected to each other by laser welding or the like, the cathode portions are connected to each other by the conductive paste 25, and the solid electrolytic capacitor element laminate 200 is manufactured. An electrolytic capacitor element or a solid electrolytic capacitor element laminate 200 is placed in a resin case 22 having an anode terminal 20 and a cathode terminal 21, and a metal strip 14 and an anode terminal 20, and a cathode part 12 and a cathode terminal 21 in the anode part. Are connected with a conductive paste 25 and covered with a lid 23 to form a solid electrolytic capacitor 100.

  Next, the solid electrolytic capacitor element used for the solid electrolytic capacitor of the present invention will be described. FIG. 2 is a diagram for explaining a manufacturing process of a solid electrolytic capacitor element used in the solid electrolytic capacitor according to the embodiment of the present invention. FIG. 2 (a) is a diagram in which a metal strip is ultrasonically welded to the end of the anode body. 2 (b) shows a cross-sectional view in which a part of the insulating resin is removed by laser light, FIG. 2 (c) shows a cross-sectional view after the first bending, and FIG. 2 (d) Shows a cross-sectional view after the second bending.

  The manufacturing process of the solid electrolytic capacitor element used for the solid electrolytic capacitor of the present invention is as follows. First, as shown in FIG. 2 (a), a metal strip 14 made of copper or a copper alloy or the like is ultrasonically welded to the anode body end portion 11. Connect by etc. Thereafter, as shown in FIG. 2B, a part of the insulating resin on the anode body end side is removed by laser processing to form an insulating resin removing portion 13a. Thereafter, as shown in FIG. 2 (c), the anode body is subjected to a first bending process at a substantially right angle at the end of the anode body, and then a second bending is performed at a substantially right angle as shown in FIG. 2 (d). By performing the processing, the metal strip piece 14 is disposed in the insulating resin removing portion 13a. The laser processing referred to here is a method in which a resin is vaporized (so-called ablation) by irradiation with a solid-state laser such as a YAG laser, a high-power laser for processing such as a carbon dioxide laser, or an excimer laser.

  As for the connection of the metal strip piece 14 to the anode body end portion 11, it is preferable from the connection strength and electrical resistance that the entire surface of the metal strip plate piece 14 is connected to the anode body end portion 11. Therefore, in order to avoid the harmful effects caused by the heat generated by welding, the connection is made away from the cathode portion. By removing the insulating resin on the anode body end side by laser processing, the anode body end part can be folded back 180 degrees. In laser processing, the output can be adjusted to reduce the influence on the cathode portion. The insulating resin requires a predetermined space for separation from the anode part when forming the cathode part, but can be removed after the cathode part is formed. Although the example in which the bending process is divided into two stages is shown, it can be folded at a time. The length of the folded portion is longer than the length of the metal strip and is preferably within 1.5 times from the viewpoint of miniaturization.

  Next, at the end 11 of the anode body shown in FIG. 2 (d), a solid electrolytic capacitor element 10 made of a copper or copper alloy metal strip 14 welded and folded to form an anode is used alone or as such. Are laminated to form a solid electrolytic capacitor element laminated body and placed in a resin case. In the formation of the solid electrolytic capacitor element laminate, as shown in FIG. 1, the anode portion is connected to the anode strip and the metal strip using resistance welding or laser welding, and the cathode portion 12 is made of a conductive paste 25. Connect. Since connection by resistance welding or laser welding between the anode portions of the laminated body is sufficient by spot connection, the influence on the cathode portion due to connection on the metal strip piece is reduced.

  Next, as shown in FIG. 1, the solid electrolytic capacitor element laminate 200 is arranged inside a box-shaped molded resin case 22 having an anode terminal 20 and a cathode terminal 21 formed from a lead frame on the bottom surface. The upper surface of the anode terminal 20 and the lower surface of the metal strip piece 14 welded to the anode body end portion 11 at the lower end are connected by the conductive paste 25, and the lowermost cathode portion 12, the cathode terminal 21, Are connected by a conductive paste 25. Here, the anode terminal 20 and the cathode terminal 21 have a flat plate shape and are formed in the same plane as the substrate mounting surface. The molded resin case 22 is formed by insert molding so as to fill the gap between the anode terminal 20 and the cathode terminal 21 and to mechanically connect both terminals, and to have a wall side around the solid electrolytic capacitor element. . The solid electrolytic capacitor 100 is obtained by covering the wall side with a box-shaped lid 23 and enclosing the solid electrolytic capacitor laminate 200.

  With such a configuration, the metal strip 14 is disposed at a position before the insulating resin 13 is removed by folding back the anode body end portion 11, so that the space 24 of the anode portion located at the anode body end portion 11. Therefore, it is possible to reduce the size of the resin case 22 of the mold exterior.

  Embodiments of the present invention will be described below with reference to the drawings.

  A solid electrolytic capacitor according to an embodiment of the present invention is a solid electrolytic capacitor on a rectangular flat plate, and is called a three-terminal transmission line element type. As shown in FIGS. 1 and 2, phosphoric acid is formed on the surface of the anode body 15 of the valve action metal made of Al having a surface area of 100 μm, which has been enlarged by etching, that is, having a thickness of 100 μm. A dielectric film 16 was formed as an anodic oxide film by applying 6 V in an aqueous solution, and the anode body 15 on which the dielectric film 16 was formed was punched into dimensions of 10 mm in length and 5 mm in width.

  After forming the insulating resin 13 using an epoxy resin and separating the anode portion and the cathode portion, the oxidizer solution of ferric p-toluenesulfonate and the monomer solution of 3,4-ethylenedioxythiophene are alternately used. The conductive polymer layer 17 was formed by dipping a plurality of times, and then the graphite layer 4 and the silver paste 5 were sequentially formed to produce the solid electrolytic capacitor element 10 as the cathode layer 12.

  Thereafter, as shown in FIG. 2A, a metal strip 14 (width 0.8 mm × length 7 mm × thickness 0.1 mm) made of copper at the anode body end 11 of the solid electrolytic capacitor element; Ultrasonic welding.

  Thereafter, a part of the insulating resin 13 is removed by laser processing at an intensity of 50 J, and then the anode body end portion 11 is folded back in the order shown in FIG. After the folding, the folding dimension is appropriately adjusted so that the metal strip piece 14 and the anode terminal 20 face each other.

  After the anode body end portion 11 is folded, as shown in FIG. 1, the metal strip 14 connected to the anode body end portion 11 and the lower surface of the anode terminal 20 are inserted into the molded resin case 22. The cathode portion 12 is connected to the cathode terminal 21 via the conductive paste 25, and the cathode portion 12 is connected to the cathode terminal 21 via the conductive paste 25. Then, the solid electrolytic capacitor 100 was obtained by covering the wall side with a box-shaped lid 23 and enclosing the solid electrolytic capacitor laminate 200. Further, the resin case molded by the present invention can be reduced in size by about 10%.

  The solid electrolytic capacitor and the manufacturing method according to the present invention are applied to capacitors used in electronic equipment and electrical equipment. Further, the present invention is applied to a transmission line element using a solid electrolytic capacitor and a manufacturing method, an electronic device, particularly a decoupling circuit.

Sectional drawing showing the solid electrolytic capacitor of embodiment of this invention. The figure explaining the manufacturing process of the solid electrolytic capacitor element used for the solid electrolytic capacitor of embodiment of this invention, Fig.2 (a) is sectional drawing by which the metal strip piece was ultrasonically welded to the anode body edge part, FIG. FIG. 2B is a cross-sectional view after removing a part of the insulating resin with a laser beam, FIG. 2C is a cross-sectional view after the first bending, and FIG. 2D is a cross-sectional view after the second bending. The figure showing the conventional solid electrolytic capacitor, FIG.3 (a) is sectional drawing which shows the whole, FIG.3 (b) is sectional drawing of the solid electrolytic capacitor element.

Explanation of symbols

4 Graphite layer 5 Silver paste 10 Solid electrolytic capacitor element 11 Anode body end portion 12 Cathode portion 13 Insulating resin 13a Insulating resin removing portion 14 Metal strip 15 Anode body 16 Dielectric film 17 Conductive polymer layer
20 Anode terminal 21 Cathode terminal 22 Resin case 23 Lid 24 Anode space 25 Conductive paste 100 Solid electrolytic capacitor 200 Solid electrolytic capacitor element laminate

Claims (5)

  A plate-like solid electrolytic capacitor element having an anode part at the end and a cathode part at the center or a solid electrolytic capacitor element laminate formed by laminating the solid electrolytic capacitor element, and an anode terminal connected to the anode part And a cathode terminal connected to the cathode portion, wherein the anode portion has a structure in which an end portion of an anode body to which a metal strip piece is connected is folded. .   The anode terminal and the cathode terminal have a flat plate shape, are formed on the same plane as a substrate mounting surface, and have a bottom surface portion that fills a gap between the anode terminal and the cathode terminal and mechanically connects the plane. A resin case having a side wall orthogonal to the resin case, the anode terminal and the cathode terminal are exposed on the inner bottom surface of the resin case, and the anode and cathode of the solid electrolytic capacitor element or the solid electrolytic capacitor element laminate The solid electrolytic capacitor according to claim 1, wherein the solid electrolytic capacitor is connected to a portion.   After forming a dielectric film on the anode body composed of a plate or foil of a valve metal that has been enlarged, the end of the anode body is separated by an insulating resin to provide an anode portion, and a solid electrolyte is formed on the dielectric film in the center. A step of forming a layer and a conductive material layer to provide a cathode portion, a step of connecting a metal strip piece to the end portion of the anode body, and a solid electrolysis by folding back the end portion of the anode body to which the metal strip piece piece is connected. A method for producing a solid electrolytic capacitor, comprising: a step of producing a capacitor element; a step of connecting an anode terminal to the metal strip piece; and a step of connecting a cathode terminal to the cathode portion.   After forming a dielectric film on the anode body composed of a plate or foil of a valve metal that has been enlarged, the end of the anode body is separated by an insulating resin to provide an anode portion, and a solid electrolyte is formed on the dielectric film in the center. A step of forming a layer and a conductive material layer to provide a cathode portion, a step of connecting a metal strip piece to the end portion of the anode body, and a solid electrolysis by folding back the end portion of the anode body to which the metal strip piece piece is connected. A step of producing a capacitor element, a step of laminating the solid electrolytic capacitor elements to connect anode portions to each other and a cathode portion to produce a solid electrolytic capacitor element laminate, and an anode on the metal strip of the anode portion A method for manufacturing a solid electrolytic capacitor, comprising: connecting a terminal; and connecting a cathode terminal to the cathode portion.   A step of disposing an anode terminal and a cathode terminal on a bottom surface on the same plane and forming a resin case having a bottom surface portion and a side wall portion by an insert molding method; and the anode portion of the solid electrolytic capacitor element or the solid electrolytic capacitor element laminate A step of connecting the anode terminal to the metal strip piece, a step of connecting the cathode terminal to the cathode portion, and a step of connecting a lid covering the upper side of the resin case to the resin case. The method for producing a solid electrolytic capacitor according to claim 3 or 4.

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