JP6430737B2 - Solid electrolytic capacitor - Google Patents

Description

  The present invention relates to a solid electrolytic capacitor, and more particularly to a solid electrolytic capacitor suitable for a chip type.

  A solid electrolytic capacitor is used for a decoupling circuit and a power supply circuit of a CPU mounted on a mobile phone or a notebook personal computer.

  In Patent Document 1, an insulator made of insulating tape or insulating paint is provided at the tip of the anode terminal component, and the cathode layer of the capacitor element is brought into contact with the tip of the anode terminal component and the cathode terminal component. A miniaturized chip capacitor is described.

  Patent Document 2 discloses a capacitor element in which a cathode layer is formed on an outer surface, and a coupling portion between an end surface from which an anode lead protrudes and a lower surface is formed in a curved portion that is bent obliquely downward. A chip capacitor is described.

Japanese Patent Laid-Open No. 2001-6777 JP 2009-231314 A

  According to the configuration of Patent Document 1, there is a problem that it is difficult to ensure insulation with only an insulating tape or an insulating paint in mass production in consideration of manufacturing variations.

  According to the configuration of Patent Document 2, there is still a concern about poor flow of the exterior resin, and there is a problem that it is difficult to ensure insulation in mass production.

  That is, in the conventional capacitor element configuration, if the volume of the anode body is increased in order to satisfy the size reduction and capacity increase required for the solid electrolytic capacitor, the cathode layer and anode terminal formed on the surface of the anode body There was a problem that they were close and short-circuited.

  Accordingly, an object of the present invention is to provide a solid electrolytic capacitor having a low possibility of short-circuit even when the volume of the anode body is increased as much as possible.

  In order to solve the above problems, a solid electrolytic capacitor of the present invention includes an anode body in which a dielectric layer, an electrolyte layer and a cathode layer are formed on the surface of a sintered body made of a valve action metal, and the anode body. A capacitor element having a derived anode lead wire, an anode terminal connected to the anode lead wire through an anode portion, a cathode terminal connected to the cathode layer, the capacitor element, the anode terminal, and the cathode A solid electrolytic capacitor comprising a sheathing resin that covers a terminal so that a part of the anode terminal and a part of the cathode terminal are exposed, the part facing the anode part or the anode terminal and closest to the anode part A part of the anode body including the insulating layer is provided with an insulating resin layer as an outermost layer.

  The solid electrolytic capacitor of the present invention is characterized in that the cathode layer is not provided in a part of the anode body that includes the portion that is closest to and faces the anode portion or the anode terminal.

  The solid electrolytic capacitor of the present invention is characterized in that a concave portion is formed in a part of the anode body that includes the portion that is closest to the anode portion or the anode terminal.

  The concave portion of the solid electrolytic capacitor of the present invention is stepped.

  The concave portion of the solid electrolytic capacitor of the present invention is roughened.

  In the method for producing a solid electrolytic capacitor of the present invention, after the insulating resin layer is formed on a part of the surface of the sintered body, the dielectric layer, the electrolyte layer, and the cathode are formed on the other surface of the sintered body. The method includes the step of forming a layer.

  In the method for producing a solid electrolytic capacitor of the present invention, the recess is formed in a part of the surface of the sintered body, the insulating resin layer is formed in the recess, and then the dielectric is formed on the other surface of the sintered body. The method includes a step of forming a body layer, the electrolyte layer, and the cathode layer.

  In the present invention, an insulating resin layer is disposed on a part of the anode body, that is, on an end portion or an end face of the anode body facing the anode portion or the anode terminal.

  Thereby, it becomes possible to arrange | position an anode body to an anode part or anode terminal vicinity. That is, the volume of the anode body that contributes to an increase in capacitance is increased, and a short circuit between the cathode layer formed on the surface of the anode body and the anode portion or the anode terminal is prevented.

  In other words, in the solid electrolytic capacitor, the capacitance value can be increased as much as possible while maintaining a small or thin shape.

  By adopting a configuration in which the cathode layer is not formed between the insulating resin layer and the sintered body, a short circuit can be prevented more reliably and the volume of the anode body can be increased.

  By providing a recess in a part of the anode body adjacent to the anode section or the anode terminal, a short circuit can be prevented more reliably and the volume of the anode body can be increased.

  Any shape can be used for the concave portion, but it is more preferable to provide a stepped concave portion so as to follow the concave and convex shapes of the anode portion and the anode terminal.

  The step-shaped concave portion prevents dripping of the insulating resin, and thus contributes to more reliable and easy formation of the insulating resin layer.

  For the same reason, it is also preferable to roughen the inner surface and the periphery of the concave portion with grooves and irregularities.

  The insulating resin layer is appropriately selected from known materials and known means, and it is more preferable to use a water-repellent fluorine-based resin or silicon-based resin that has an effect of suppressing the formation of the cathode layer.

  For example, an insulating resin is applied in advance to the surface of a sintered body obtained by molding a valve action metal powder such as tantalum and sintering it at a high temperature, in the vicinity of the anode part or anode terminal. After forming the insulating resin layer, after forming a dielectric layer made of an oxide film, for example, an electrolyte layer made of a conductive polymer layer, and a cathode layer made of a graphite layer or a silver layer by a known means, An outer packaging is applied to obtain a solid electrolytic capacitor.

  In the case where the concave portion is formed in the portion where the insulating resin layer is formed, it is preferable to obtain a sintered body by providing a convex portion having a predetermined shape in advance in a mold for molding the valve action metal powder.

  Or you may process the obtained sintered compact by a well-known means, and may form a recessed part.

  By the above-described manufacturing method, an insulating resin layer is formed as an outermost layer on a part of the anode body facing and adjacent to the anode portion or the anode terminal, and at least a cathode layer is not formed between the sintered body and the insulating resin layer An electrolytic capacitor is obtained.

  According to the present invention, it is possible to obtain a solid electrolytic capacitor that increases the capacitance while maintaining a small or thin shape and has a low possibility of short-circuiting, and a method for manufacturing the same.

It is sectional drawing which shows embodiment in the solid electrolytic capacitor of this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a cross-sectional view showing an embodiment of the solid electrolytic capacitor of the present invention.

  The capacitor element includes an anode body 1 and an anode lead wire 2 led out from the anode body 1. One end of the anode lead wire 2 is connected to an anode terminal 4 including an external anode terminal 43 that is electrically connected to the internal anode terminal 41 through an anode via 42 via an anode portion 3 including a conductive member 31 and solder 32. .

  The anode body 1 is made of a sintered body obtained by sintering a valve action metal powder at a high temperature after molding. A part of the sintered body includes a recess 11 having an insulating resin layer 9 as an outermost layer, and a dielectric layer made of an oxide film (not shown) on the other surface excluding the recess 11. An electrolyte layer such as a molecular layer, and a cathode layer 7 made of a graphite layer or a silver layer are sequentially formed.

  The cathode layer 7 is connected via a conductive adhesive 71 to the cathode terminal 5 including an external cathode terminal 53 that is electrically connected to the internal cathode terminal 51 through a cathode via 52.

  The anode via 42 is formed in the substrate 8, and the internal anode terminal 41 and the external anode terminal 43 are formed to face the front and back of the substrate 8.

  The cathode via 52 is opened in the substrate 8, and the internal cathode terminal 51 and the external cathode terminal 53 are formed to face the front and back of the substrate 8.

  The capacitor element, the anode portion 3, the internal anode terminal 41, the conductive adhesive 71 and the internal cathode terminal 51 are covered with the exterior resin 6 so as to be integrated.

  A method for obtaining the solid electrolytic capacitor having the above configuration will be exemplified below.

  A tantalum powder as a valve action metal powder is put into a molding die provided with a recess 11, and at the same time, an anode lead 2 made of tantalum is inserted. Get a tie.

  Subsequently, a fluororesin having water repellency is applied, subjected to high temperature treatment, and cured to form the insulating resin layer 9.

  Further, the anode body 1 is formed by sequentially laminating a dielectric layer made of an oxide film, an electrolyte layer made of a conductive polymer layer, a graphite layer as a cathode layer 7 and a silver layer on the surface of the sintered body by a known method. obtain.

  At this time, at least the graphite layer and the silver layer as the cathode layer 7 are not formed in the recess 11 formed in the insulating resin layer 9 or in the vicinity of the recess 11.

  Subsequently, the anode lead wire 2 and the conductive member 31 made of a material appropriately selected from known alloys are connected by means appropriately selected from known means such as welding, and further, via the solder 32, Connect to internal anode terminal 41. The conductive member 31 adjusts the welding position so as to maintain a certain distance from the anode body 1.

  The cathode layer 7 formed on the surface of the anode body 1 is connected to the internal cathode terminal 51 via the conductive adhesive 71.

  A substrate 8 made of, for example, glass epoxy resin, provided with the anode terminal 4 and the cathode terminal 5 is prepared in advance.

  Subsequently, the substrate 8 on which the capacitor element is mounted is packaged by a known means, for example, using a commonly used exterior resin 6 made of a liquid epoxy resin containing a glass filler.

  The external anode terminal 43 and the external cathode terminal 53 are exposed on the back surface of the substrate 8, that is, the surface on which the capacitor element is not mounted.

  Further, the chip-type solid electrolytic capacitor 100 is obtained by performing cutting and finishing using a known method.

  A tantalum powder 1.07 times larger than the conventional tantalum powder is carried into a molding die having a stepped step as the recess 11, and the anode lead 2 made of tantalum is inserted into a predetermined position. As a result, a sintered body to be the anode body 1 was obtained.

  Next, a fluororesin having water repellency was applied to the recess 11 with a tube having a thin tip, and cured by high-temperature treatment at 150 ° C. for 3 hours to form an insulating resin layer 9.

  Subsequently, a dielectric layer made of a tantalum oxide film, a solid electrolyte layer made of a conductive polymer layer, a cathode layer 7 made of a graphite layer and a silver layer are formed on the sintered body by a known method. did.

  Since the water-repellent insulating resin layer 9 is formed in the concave portion 11, it was confirmed that at least the cathode layer was not formed on the concave surface of the concave portion 11 or in the vicinity of the concave surface.

  In addition, the manufacturing voltage of a sintered compact and the formation voltage at the time of forming a dielectric material layer were made into the same voltage as the conventional product which is a comparative example.

  Next, the anode lead wire 2 and the conductive member 31 were resistance welded. At this time, the welding position was adjusted so that the distance between the anode body 1 and the surface of the conductive member 31 facing the anode body 1 was 0.2 ± 0.1 mm.

  Subsequently, the cathode layer 7, that is, the cathode layer 7 formed on the surface of the anode body 1 and the internal cathode terminal 51 were connected via a conductive adhesive 71.

  Further, it was molded with an exterior resin 6 made of a liquid epoxy resin containing a glass filler, and was heated and cured at 150 ° C. for 300 seconds to complete the exterior. Thereafter, the solid electrolytic capacitor 100 of the present invention was obtained by cutting into individual pieces and forming a chip shape.

  As a comparative example, 100 conventional products without the recess 11 and the insulating resin layer 9 were prepared. The conventional product was manufactured under the same conditions and the same method except that the step of forming the recess 11 and the step of forming the insulating resin layer 9 were excluded from the above manufacturing process.

  The initial capacitance value was measured for each of 100 solid electrolytic capacitors of the present invention and the conventional product. Table 1 shows the measurement results.

  Here, the relative capacity value indicates the average of the initial capacity values when the average value of the conventional products is 1.

Table 1 also shows the measurement results of the dimensions of the anode body 1 in the lead-out direction of the anode lead wire 2.

  From the fact that the relative capacity value of the product of the present invention is increased, it is clear that the capacitance value increased due to the increase in the valve metal powder, that is, the volume of the anode body. Therefore, it can be seen that the loss of capacitance due to the formation of the recess and the reduction in the surface area of the cathode layer is negligible.

  In the configuration of the product of the present invention described in Example 1, instead of forming a stepped step on the concave surface of the concave portion 11, a groove is provided to roughen the surface, and a water-repellent fluororesin is sprayed to form the insulating resin layer 9. 100 solid electrolytic capacitors 100 were obtained under the same conditions and method as in Example 1.

  When the capacitance value was measured by the same method as in Example 1, the relative capacitance value of the capacitance value was an average value of 1.070, and it was confirmed that the same effect as in Example 1 was achieved. did.

  From the above, it was possible to obtain a solid electrolytic capacitor that increases the capacitance value and has a low possibility of short-circuiting while maintaining a small or thin shape.

  While the embodiments and examples of the present invention have been described above, the present invention is not limited to the above, and changes and modifications can be made without departing from the gist of the present invention. That is, various changes and modifications that can be made by those skilled in the art are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 Anode body 11 Recessed part 2 Anode lead wire 3 Anode part 31 Conductive member 32 Solder 4 Anode terminal 41 Internal anode terminal 42 Anode via 43 External anode terminal 5 Cathode terminal 51 Internal cathode terminal 52 Cathode via 53 External cathode terminal 6 Exterior resin 7 Cathode layer 71 Conductive adhesive 8 Substrate 9 Insulating resin layer 100 Solid electrolytic capacitor

Claims (3)

An anode body in which a dielectric layer, an electrolyte layer and a cathode layer are formed on the surface of a sintered body made of a valve action metal, a capacitor element having an anode lead wire derived from the anode body, and the anode lead wire An anode terminal connected via an anode part, a cathode terminal connected to the cathode layer, the capacitor element, the anode terminal and the cathode terminal, a part of the anode terminal and a part of the cathode terminal A solid electrolytic capacitor comprising an exterior resin covering so as to be exposed, wherein a portion of the anode body that includes the portion closest to the anode portion or the anode terminal does not have the cathode layer. A solid electrolytic capacitor , wherein stepped recesses are formed, and an insulating resin layer is provided as an outermost layer in the recesses . The solid electrolytic capacitor according to claim 1, wherein the concave portion is roughened. After forming the recess in a part of the surface of the sintered body and forming the insulating resin layer in the recess, the dielectric layer, the electrolyte layer, and the cathode layer are formed on the other surface of the sintered body. the method for producing a solid electrolytic capacitor according to claim 1 or 2, characterized in that it comprises a step of forming.

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