JP2010219127A - Surface mounting type solid electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent forming of a short circuit between a positive electrode terminal and a negative electrode terminal, and to reduce connection resistance at the positive electrode terminal, relating to a surface mounting type solid electrolytic capacitor. <P>SOLUTION: The surface mounting type solid electrolytic capacitor includes a positive electrode body 11 of valve action metal, with its end part 14 being connected to a positive electrode terminal 20 which is a metal plate through a positive electrode conductive member 19 and a conductive bond 23. Here, the cross section of the positive electrode terminal 20 includes a shape of L, and a rising portion of the positive electrode terminal 20 is arranged on the side close to the negative electrode terminal 21 while a flat part is arranged on the side away from the negative electrode terminal 21. Thus, the conductive bond 23 is prevented from laterally spreading to the negative electrode terminal 21 side, requiring no limitation on the amount of use of the conductive bond. Then, the connection resistance of the solid electrolytic capacitor is reduced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solid electrolytic capacitor, and more particularly to a surface mount type solid electrolytic capacitor in which a conductive adhesive is used to connect electrode terminals.

  In a noise filter or the like mounted on an electronic circuit that is driven at a high frequency, a small capacitor is required as its constituent element. Surface mount type solid electrolytic capacitors are often used as capacitors for such applications. A surface-mount type solid electrolytic capacitor generally has a plate-like anode body made of a valve metal whose surface is enlarged in the anode region (the surface is enlarged by providing deep irregularities on the surface). Thus, a dielectric layer is formed in a partial region of the surface of the anode body. A solid electrolyte layer is formed on the surface of the dielectric layer, and a cathode forming body composed of a graphite layer and a silver electrode layer is formed on the surface, and a cathode terminal is connected through these. On the other hand, a lead portion is formed on a part of the surface of the anode body other than the region where the dielectric layer is formed, and an anode terminal is connected via the lead portion. Here, a conductive adhesive is used to connect the cathode forming body and the cathode terminal, and the anode body or the lead part and the anode terminal.

  The surface mount type solid electrolytic capacitor generally has a two-terminal type or a three-terminal type configuration. Here, the two-terminal type capacitor has a configuration in which one anode terminal and one cathode terminal are provided on the lower surface of a capacitor element including an anode body, a dielectric layer, a solid electrolyte layer, and a cathode forming body. The three-terminal type capacitor has a configuration in which a cathode terminal at the center is sandwiched between the lower surface of the capacitor element and one anode terminal is provided on each side of the capacitor terminal. Patent Document 1 previously proposed by the applicants describes an example of such a conventional three-terminal surface mount solid electrolytic capacitor.

  The prior art of the surface mount type solid electrolytic capacitor described in Patent Document 1 will be described with reference to FIG. FIG. 3 is a diagram showing an example of a three-terminal surface mount type solid electrolytic capacitor described in Patent Document 1, FIG. 3 (a) is a top view, and FIG. 3 (b) is an A- FIG. 3C is a cross-sectional view at A, and FIG. As shown in FIG. 3, the external shape of the surface mount type solid electrolytic capacitor is generally a rectangular flat plate. Further, as shown in FIG. 3C, a cathode terminal 61 having a large area is provided at the center of the bottom surface, and anode terminals 60 are provided on both the left and right sides of the cathode terminal 61, respectively. This constitutes an electrode terminal. All of these three electrode terminals have a flat plate shape and are arranged on the same plane constituting the bottom surface of the surface mount type solid electrolytic capacitor. Although Patent Document 1 mainly describes a case where a plurality of capacitor elements are stacked on each other, there is no particular difference in the description of the prior art even if the capacitor element is only one layer. The case of only one layer was described.

  The mold resin case 64 in FIG. 3C has a bottom surface portion that fills the gap between the anode terminal 60 and the cathode terminal 61 and insulates them from each other and mechanically connects the electrode terminals. Have side walls that stand upright. The upper periphery of the mold resin case 64 is covered with a lid portion 66, and the internal capacitor element is hermetically sealed by the mold resin case 64 and the lid portion 66. An adhesive 67 is applied to the upper end of the mold resin case 64 and is fixed to the lid 66 by an organic adhesive.

  The internal structure of this surface mount type solid electrolytic capacitor is as shown in FIG. In FIG. 3B, a plate-like anode body 51 made of a valve metal is installed at the center in the height direction of the surface mount type solid electrolytic capacitor. Both surfaces of the anode body 51 are enlarged. In the region of the central portion 52, dielectric layers (not shown) are provided on both the upper and lower surfaces of the anode body 51, respectively. A solid electrolyte layer 55 is provided on the outer side of the dielectric layer, and the surface of the anode body 51 is expanded to fill the surface of the dielectric layer having irregularities with the solid electrolyte. A graphite layer 56 and a silver electrode layer 57 are further provided in this order on the surfaces of the solid electrolyte layers 55 on the upper and lower sides of the anode body 51, thereby forming a capacitor element. In the region of the central portion 52, the lower silver electrode layer 57 in the figure is connected to the cathode terminal 61 through the conductive adhesive 62, and the end portions 54 on both sides of the anode body 51 are made of a metal anode conduction piece 59. And connected to the anode terminal 60 via the conductive adhesive 63. The silver electrode layer 57 is generally formed by applying a silver paste and then solidifying it by drying.

  Each of the dielectric layer, the solid electrolyte layer 55, the graphite layer 56, and the silver electrode layer 57 is also present on two side surfaces of the capacitor element, which are parallel to the plane shown as a cross-sectional view in FIG. It is formed to wrap around. Therefore, the two cathode formation bodies formed above and below the capacitor element with the anode body 51 interposed therebetween are electrically connected to the cathode terminal 61 by the graphite layer 56 and the silver electrode layer 57 formed on the side surfaces. It will be. Further, a resist forming portion 53 which is a region for ensuring insulation between the anode terminal 60 and the cathode terminal 61 is provided between the central portion 52 and the end portion 54 in the surface region of the anode body 51. . In the resist forming portion 53, a resist layer 58 made of an insulating resin or the like is provided on the surface of the anode body 51, thereby preventing the solid electrolyte layer 55 from overflowing in the direction of the end portion 54. Further, a protrusion 65 is provided as a part of the mold resin case 64 between the anode terminal 60 and the cathode terminal 61, and serves to prevent the conductive adhesive 63 from overflowing from the anode region. . The protruding portion 65 is also provided in the region of the resist forming portion 53.

  A metal foil such as aluminum (Al), tantalum (Ta), or niobium (Nb) is suitable as the anode body used for the surface mount type solid electrolytic capacitor. Etching by chemical treatment or electrochemical treatment is suitable as the surface expansion method, and anodic oxidation by chemical conversion treatment is suitable as the method of forming the dielectric layer. By etching, deep irregularities called etching pits are formed on the surface of the anode body to increase the surface area, and an anodic oxide film that is a dielectric layer is formed on the surface by anodization. Furthermore, it is preferable to use a conductive functional polymer film as the solid electrolyte layer disposed on the surface of the dielectric layer.

  The graphite layer and silver electrode layer that are further formed on the surface of the solid electrolyte layer are on the cathode side through the solid electrolyte layer, and the silver electrode layer is heated and dried by applying a silver paste that is a conductive adhesive It can be formed by a method such as Further, the anode conductive piece interposed between the anode body and the anode terminal is a small piece of metal and is generally connected by a method such as welding to the anode body. Each of the anode terminal and the cathode terminal can be connected to the capacitor element with a conductive adhesive, and the mold resin case and the lid are preferably formed of an insulating resin such as an epoxy resin.

  In the conventional example of the surface mount type solid electrolytic capacitor described above, the conductive adhesive is used as described above in order to connect the anode terminal to the anode body through the anode conductive piece. The conductive adhesive is obtained by dispersing metal particles such as silver in an organic solvent, and is basically the same type as the silver paste applied to provide the silver electrode layer on the cathode forming body. Here, when a conductive adhesive is used when connecting the anode conductive piece and the anode terminal, the conductive adhesive is relatively fluid, so that it overflows from the connecting portion between the two, and this is the side of the cathode terminal. In some cases, a short circuit will occur.

  In the configuration of FIG. 3B, a protruding portion 65, which is a structure of the molded resin case 64, is provided between the anode terminal 60 and the cathode terminal 61. The protrusion 65 prevents the conductive adhesive from overflowing. Here, in consideration of the necessity to control the connection area between the conductive adhesive 62 and the cathode terminal 61, it is desirable that a slight gap exists between the protrusion 65 and the resist layer 58. However, when such a gap exists, the conductive adhesive 63 on the anode terminal side may flow from the gap to the cathode terminal side during the assembly of the capacitor, thereby causing a short circuit between the electrode terminals.

  In order to prevent the occurrence of such a short circuit, conventionally, the amount of the conductive adhesive used for the connection of the anode terminal is limited to prevent the conductive adhesive from overflowing. . However, when the amount of use is limited in the conductive adhesive, the area where the conductive adhesive actually contacts is limited to only a part of the connection surfaces of the anode terminal facing the anode conductive piece. . In general, it is known that connection resistance becomes larger in connection with a conductive adhesive than welding or the like, and in order to reduce connection resistance, it is desirable to increase the connection area as much as possible. However, in the conventional surface-mount type solid electrolytic capacitor, the connection area between the capacitor element and the anode terminal cannot be kept sufficiently large for the reasons described above.

  Patent Document 2 has been previously proposed by the applicant to solve the above-mentioned problem, and prevents the conductive adhesive from overflowing in the connection portion of the anode terminal in a three-terminal surface-mount solid electrolytic capacitor or the like. However, the connection area in the connection portion is increased. The structure of the surface mount type solid electrolytic capacitor described in Patent Document 2 will be described with reference to FIG. 4, FIG. 4 (a) is a top view, FIG. 4 (b) is a cross-sectional view taken along line AA of FIG. 4 (a), and FIG. 4 (c) is a bottom view. The internal structure of this capacitor is as shown in FIG. 4B, the configuration of each of the details constituting the capacitor is basically similar to that of the conventional example shown in FIG. 3, but the shape of the anode terminal 80 is greatly different from that of FIG. ing.

  4B, the anode terminal 80 has an L-shaped shape having a flat portion and an upright portion, and the upright portion is immediately on the right side of the anode body 71 and is the right end surface of the anode body 71. The conductive adhesive 82 is electrically connected. The upright portion of the anode terminal 80 is also connected to the side surface of the anode conduction piece 79 by a conductive adhesive 83, and the area required for connection with the two is compared with the conventional example shown in FIG. This is an increase in the connection area of the anode terminal 80. In the electrical connection with the anode conductive piece 79 in the flat portion of the anode terminal 80, the amount of the conductive adhesive 83 is limited by limiting the amount of the conductive adhesive 83 used, as in the conventional example of FIG. Overflow can be prevented. In addition to the shape of the anode terminal 80 in FIG. 4, the shape of the application region of the conductive adhesive 83 is also different from that in the conventional example of FIG. 3, and the mold resin case 84 is provided with a protrusion. Absent. However, the shape of each component of the other capacitor is basically the same as in FIG.

JP 2006-128247 A JP 2008-117901 A

  The surface mount type solid electrolytic capacitor having the configuration described in Patent Document 2 has a certain effect in reducing the connection resistance inside the capacitor while preventing the conductive adhesive from overflowing in the connecting portion of the anode terminal. Is. However, there has been a great demand from users for reducing the internal resistance of the capacitor, and a surface mount type solid electrolytic capacitor having a structure capable of realizing further reduction in resistance has been demanded. The present invention provides a surface-mount type solid electrolytic capacitor that can achieve a further reduction in internal resistance than conventional ones.

  In order to solve the above-mentioned problem, in the present invention, the use of an anode terminal having a L-shaped cross section is the same as that of the surface mount type solid electrolytic capacitor described in Patent Document 2, but the L-shaped used is used. The shape of the anode terminal of the mold was reversed. That is, unlike the case of Patent Document 2, the upright portion is arranged on the side close to the cathode terminal, and the flat portion is arranged on the side far from the cathode terminal. Therefore, in the case of a three-terminal surface mount type solid electrolytic capacitor, the upright portions of the L-shaped anode terminal are respectively arranged on the side facing the cathode terminal in the center portion. As a result, the anode terminal is connected and fixed to the anode body and the anode conductive piece by the conductive adhesive at two portions of the upright portion, the side surface facing the anode body and the surface facing the anode body of the flat portion (the upper surface of the anode terminal). Is done. This configuration is the same in the case of a two-terminal surface-mount type solid electrolytic capacitor, and the upright portion of the L-shaped anode terminal is also arranged on the side facing the cathode terminal.

  In the three-terminal surface mount solid electrolytic capacitor of the present invention, the top of the upright portion of the L-shaped anode terminal and the anode body are in contact with each other without a gap. Therefore, the conductive adhesive does not overflow from the top of the upright portion and flows out to the cathode terminal side. Therefore, in the present invention, the restriction on the amount of the conductive adhesive used for connecting the anode terminal is relaxed. Is done. This situation is the same in connection fixing at the flat portion of the L-shaped anode terminal. When the amount of the conductive adhesive used is sufficient, it is considered that the applied conductive adhesive overflows from the coated area in this flat portion. It only accumulates in the region between the side surfaces of the resin case, and does not cause a situation in which it overflows to the cathode terminal side and causes a short circuit between the electrode terminals.

  In the case of Patent Document 2, it was necessary to limit the amount of the conductive adhesive used in connecting the flat portion of the L-shaped anode terminal. There is no need to limit the amount of conductive adhesive used in both the flat part and the flat part. Accordingly, the entire surface of the opposing surface of the anode terminal, the anode body, and the anode conducting piece can be used as a connection surface using a conductive adhesive.

  Comparing the present invention and the connecting portion of the anode terminal in the surface mount type solid electrolytic capacitor described in Patent Document 2, in the case of Patent Document 2, the upright portion of the L-shaped anode terminal is opposed to the end face of the anode body. This is different from the present invention in that the end face of the anode body is used for connection with the anode terminal. Therefore, when a dielectric layer or the like is not provided on the end face of the anode body to be used and the anode body is sufficiently thick, the connection area with the end face of the anode body becomes large. In addition, a reduction in internal resistance comparable to the present invention can be realized. Therefore, the configuration of the three-terminal type and two-terminal type surface mount solid electrolytic capacitors of the present invention is such that the anode body used is relatively thin, or a dielectric layer is provided on the end face of the anode body. This is particularly effective when the end face cannot be used for electrical connection with the anode terminal.

  That is, the present invention has an anode body made of a valve metal having an enlarged surface, a dielectric layer is formed in a partial region of the surface of the anode body, and the surface of the dielectric layer A solid electrolyte layer and a cathode forming body are respectively formed in this order, a cathode terminal is connected to the cathode forming body through a conductor, and a region of the anode body in which the dielectric layer is formed An anode conducting piece is connected to a part of the surface other than the anode conducting piece, and a conductor is connected to the anode conducting piece, and an anode terminal is connected to the anode body via the anode conducting piece and the conductor. A solid electrolytic capacitor, wherein the anode terminal is formed of a metal body having an L-shaped cross section, which is composed of a combination of two flat plate-like structures of an upright portion and a flat portion that are orthogonal to each other. And the flat portion is a longitudinal direction of the anode body. Arranged in a direction parallel to the anode and connected to the anode conduction piece through the conductor, and the upright portion is arranged in a direction perpendicular to the longitudinal direction of the anode body and the anode conduction through the conductor. A surface mount type solid electrolytic capacitor, wherein the surface mount type solid electrolytic capacitor is connected to the piece and the anode body, and the upright portion is disposed on a side closer to the cathode terminal with respect to the flat portion.

  In addition, the present invention is a surface mount type solid electrolytic capacitor, wherein the conductor is made of a conductive adhesive.

  The surface mount type solid electrolytic capacitor, wherein an end portion of the upright portion of the anode terminal is in contact with the anode body.

  Further, in the present invention, the cathode forming body is composed of a graphite layer and a silver electrode layer, and the dielectric layer, the solid electrolyte layer, the graphite layer, A surface-mount type solid electrolytic capacitor characterized in that the silver electrode layers are formed in this order.

  Further, the present invention has one cathode terminal and two anode terminals having an L-shaped cross section, and each electrode terminal is disposed at a position where the first cathode terminal is sandwiched by the two anode terminals. This is a three-terminal surface-mounting type solid electrolytic capacitor.

  Furthermore, the present invention has a two-terminal type surface-mounting type characterized in that it has one cathode terminal and one anode terminal whose section is L-shaped, and each electrode terminal is arranged in parallel. It is a solid electrolytic capacitor.

  According to the present invention, an anode terminal having an L-shaped cross section is used as the anode terminal, and the upright portion of the anode terminal is disposed on the side close to the cathode terminal, and the flat portion is disposed on the side far from the cathode terminal. By disposing the anode terminal, it is possible to prevent the conductive adhesive used for connecting and fixing the anode body or anode conducting piece and the anode terminal from overflowing to the cathode terminal side. As described above, since the conductive adhesive does not overflow to the cathode terminal side, in the surface mount type solid electrolytic capacitor of the present invention, the conductive property is maintained in both the fixed and fixed portions of the cathode terminal. There is no need to limit the amount of adhesive used. For this reason, in the connection of the facing surfaces of the anode terminal, the anode body, and the anode conductive piece, the entire area can be used as a connection surface by the conductive adhesive, and the value of the connection resistance in the solid electrolytic capacitor can be reduced. Is possible.

The figure which shows the example of the 3 terminal type surface mount type solid electrolytic capacitor which concerns on embodiment of this invention. 1A is a top view, FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A, and FIG. 1C is a bottom view. The figure which shows the example of the 2 terminal type surface mount type solid electrolytic capacitor which concerns on embodiment of this invention. 2A is a top view, FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A, and FIG. 2C is a bottom view. The figure which shows the example of the 3 terminal type surface mount type solid electrolytic capacitor of patent document 1. FIG. 3A is a top view, FIG. 3B is a cross-sectional view taken along line AA of FIG. 3A, and FIG. 3C is a bottom view. The figure which shows the example of the 3 terminal type surface-mount type solid electrolytic capacitor of patent document 2. FIG. 4A is a top view, FIG. 4B is a cross-sectional view taken along line AA of FIG. 4A, and FIG. 4C is a bottom view.

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

  FIG. 1 is a diagram showing an example of a three-terminal surface-mount solid electrolytic capacitor according to an embodiment of the present invention. Here, FIG. 1A is a top view, FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A, and FIG. 1C is a bottom view.

  The three-terminal surface mount solid electrolytic capacitor of the present invention shown in FIG. 1 has an outer shape of a rectangular flat plate and is generally called a three-terminal transmission line element type. An anode body 11 exists in the center of FIG. 1B, and this anode body 11 is formed by forming a large number of holes by etching or the like on the surface of a valve-acting metal having a plate-like or foil-like valve action. The surface area is increased by about 200 times (surface expansion). Dielectric layers (not shown) are formed on the upper and lower surfaces of the central portion 12 of the anode body 11 whose surface has been enlarged. It is preferable to provide an anodic oxide film as the dielectric layer.

  As the valve metal constituting the anode body 11, it is preferable to use a metal material having a valve action such as tantalum, aluminum or niobium. A solid electrolyte layer 15 is further provided on the surface of the central portion 12 of the anode body 11 on which the dielectric layer is formed. The solid electrolyte layer 15 is generally a material having a high dielectric constant, and a conductive functional polymer film is preferably used. Specifically, pyrrole, thiophene, or the like can be used. A graphite layer 16 and a silver electrode layer 17 are further formed in this order on the surface of the solid electrolyte layer 15. As the silver electrode layer 17, it is preferable to use a silver paste which is a conductive adhesive.

  On the other hand, regarding the peripheral regions on both sides other than the central portion 12 on the surface of the anode body 11, the resist forming portion 13 is set just outside the central portion 12, and each region of the end portion 14 is set further outside. In these regions, the dielectric layer, the solid electrolyte layer 15, the graphite layer 16, the silver electrode layer 17 and the like are not provided. In the resist forming portion 13, a resist layer 18 is provided on the surface of the anode body 11, and an anode conducting piece 19 is joined to the outer end portion 14 by welding or the like, and a capacitor element is formed by these configurations. Yes. These configurations are basically the same as the capacitor elements in the surface mount type solid electrolytic capacitor described in Patent Document 1 and the like. Each of the dielectric layer, the solid electrolyte layer 15, the graphite layer 16, and the silver electrode layer 17 also wraps around the two side surfaces of the capacitor element, which are present in parallel to the plane shown in the cross-sectional view of FIG. It is formed as follows.

  The anode terminal 20 and the cathode terminal 21 have the same plane as the substrate mounting surface of the surface-mounting type solid electrolytic capacitor at the bottom, and the gap between the two is filled with a resin so as to have an electrode as a whole and be flat. Forms the bottom. This resin is a part constituting the mold resin case 24 of the solid electrolytic capacitor, and constitutes an exterior member of the surface mount type solid electrolytic capacitor together with the lid portion 26 shown in FIG. Here, in the case of a three-terminal configuration, the anode terminal 20 is provided on both sides of the cathode terminal 21 and is a metal body having an L-shaped cross section composed of an upright portion and a flat portion, and The upright portion is provided in a direction orthogonal to the longitudinal direction of the anode body 11 and is disposed on the side close to the cathode terminal 21. With this configuration, the top of the upright portion of the anode terminal 20 is in contact with the anode body 11 and the resist layer 18.

  In addition, as materials for the anode terminal 20 and the cathode terminal 21, it is preferable to use copper, a copper alloy, an iron-based material, or the like in order to reduce resistance. It is not limited. The surfaces of the anode terminal 20 and the cathode terminal 21 are preferably plated with gold, tin or the like. In FIG. 1B, a protrusion 25 is provided in a region between the anode terminal 20 and the cathode terminal 21 in the mold resin case 24. By providing the protrusion 25, the connection and fixing of the anode terminal 20 to the mold resin case 24 can be further strengthened. However, when the connection strength of the anode terminal 20 is already sufficient, the protrusion 25 is not particularly required. I do not care.

  The anode terminal 20 is connected to the anode body 11 and the anode conductive piece 19 by the conductive adhesive 23 in the standing portion and the flat portion, and the standing portion abuts against the anode body 11 and the resist layer 18 at this time, respectively. As a result, the gap that continues from the region of the end portion 14 to the cathode terminal 21 side is blocked. Therefore, in the case of the present invention, there is no possibility that the conductive adhesive 23 overflows from the top of the upright portion of the anode terminal 20 to the cathode terminal side. Thus, the surface mount type solid electrolytic capacitor of the present invention is characterized in that the conductive adhesive 23 used for connecting the anode terminal 20 does not overflow to the cathode terminal side. In addition, it is not necessary to limit the amount of conductive adhesive 23 used. For this reason, the entire surface of the facing region of the upright portion and the flat portion of the anode terminal 20 having an L-shaped cross section can be used for connection with the anode body 11 and the anode conduction piece 19, and the connection area with these is increased. Thus, the connection resistance of the surface mount type solid electrolytic capacitor can be reduced.

  Note that the conductive adhesive 22 is also used in the connection between the cathode terminal 21 and the silver electrode layer 17, but no special countermeasure is provided for the overflow from the connection region of the conductive adhesive 22. . Therefore, in order to prevent overflow, it is necessary to limit the amount of the conductive adhesive 22 used. However, since the connection area between the cathode terminal 21 and the silver electrode layer 17 is relatively larger than that in the case of the anode terminal 20, the amount of the conductive adhesive 22 is limited to limit the connection area somewhat. However, generally a larger connection area than the improved connection area at the end 14 of the anode body 11 is obtained. For this reason, since the contribution in the connection resistance of the surface mount type solid electrolytic capacitor is not so large, the necessity for improvement is small. As the conductive adhesives 22 and 23, silver paste, copper paste, solder paste or the like is preferably used. Moreover, as the coating method, a method of coating in a linear form from the end portion side of the anode body 11 using a dispenser or the like is preferable.

  FIG. 2 is a diagram showing an example of a two-terminal surface mount type solid electrolytic capacitor according to an embodiment of the present invention. Here, FIG. 2A is a top view, FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A, and FIG. 2C is a bottom view. The case of a two-terminal type surface mount solid electrolytic capacitor is the same as the case of the three-terminal type, and the anode terminal 40 arranged at the right end in FIG. 2B is a metal body having an L-shaped cross section. . Just as in the case of the three-terminal type, in the case of the two-terminal type, there is no possibility that the conductive adhesive 43 overflows from the top of the upright portion of the anode terminal 40 to the cathode terminal side. Therefore, it is not necessary to limit the amount of conductive adhesive 43 used. For this reason, the entire surface of the upright portion and the flat portion of the anode terminal 40 having an L-shaped cross section can be used for connection between the anode body 31 and the anode conduction piece 39, and the connection area between them can be increased. The connection resistance of the two-terminal surface mount type solid electrolytic capacitor can be reduced.

(Example 1, Comparative Example 1-2)
By using the method according to the present invention and the prior art, three-terminal type surface mount type solid electrolytic capacitors were respectively produced and the connection resistances were compared. First, a three-terminal surface mount type solid electrolytic capacitor according to the present invention shown in FIG. Next, a three-terminal solid electrolytic capacitor having a shape according to Patent Document 1 shown in FIG. Further, a three-terminal solid electrolytic capacitor having a shape according to the prior art shown in FIG.

  About the shape of the capacitor | condenser element which comprises a 3 terminal type surface mount-type solid electrolytic capacitor, both in Example 1 and Comparative Example 1-2 are substantially the same. As the anode body for forming the capacitor elements of Example 1 and Comparative Example 2, an aluminum foil having a length of 2.4 mm, a width of 1.5 mm, and a thickness of 150 μm whose surface was expanded by etching was used. An aluminum conversion foil was used by forming a dielectric film at the center of the film. A conductive functional polymer film having a thickness of about 15 μm is formed as a solid electrolyte layer on both sides of the aluminum conversion foil, and then a graphite layer is formed with a thickness of about 20 μm, and a silver electrode layer made of silver paste is formed with a thickness of 15 μm. This was formed into a cathode forming body. Also, a metal piece having a thickness of about 150 μm in which a silver plating film having a thickness of about 4 μm was formed on the surface of the copper alloy was prepared as an anode conductive piece. This anode conduction piece was connected to both ends of the anode body made of the aluminum formed foil by ultrasonic welding.

  As the capacitor element of Comparative Example 1, an anode body having a length as short as 2.2 mm was used because the upright portion of the L-shaped anode terminal was positioned on the end face of the anode body. Dimensions other than the length of the body are the same as in the case of Example 1 and Comparative Example 2. Further, the length of the cathode forming body formed in the central portion is the same as that in the first embodiment.

  Next, a copper alloy is used as a base material for the cathode terminal, silver plating is applied to one surface connected by a conductive adhesive during assembly, and tin plating is applied to the opposite surface. Length 1.4 mm, width 1.6 mm A metal plate having a thickness of 100 μm was prepared. The shape of this cathode terminal is the same in Example 1 and Comparative Example 1-2. On the other hand, the anode terminals prepared at the same time are all made of the same copper alloy as that of the cathode terminal, but the shapes thereof are different in Example 1 and Comparative Example 1-2. The anode terminal of Example 1 is L-shaped, the length is 1.6 mm, the height of the upright part is 200 μm, the width of the flat part is 400 μm, and the thickness is 100 μm. Of the surface of the anode terminal, about 4 μm of silver plating was applied to the L-shaped inner region connected to the anode body and the anode conductive piece with the conductive adhesive, and tin plating was applied to the opposite surface.

  The anode terminal of Comparative Example 1 is also L-shaped in the same manner as in Example 1, and the length is 1.6 mm, but the height of the upright portion is 400 μm, the width of the flat portion is 200 μm, and the thickness is 100 μm. As in Example 1, approximately 4 μm of silver plating was applied to the inner region of the L-shape connected to the anode body and the anode conductive piece by the conductive adhesive, and tin plating was applied to the opposite surface. . The anode terminal of Comparative Example 1 has a flat portion with a narrower width and a higher height of the upright portion than in Example 1, and the upright portion of the anode terminal is in contact with the end face of the anode body. The width of the anode conductive piece ultrasonically welded to the anode body is narrower than that of the first embodiment because the upright portion of the anode terminal is located on the end face of the anode body. The anode terminal of Comparative Example 2 was a flat plate having a width of 400 μm, and the surface on the side to be connected with the conductive adhesive during assembly was subjected to silver plating, and the opposite surface was subjected to tin plating.

  Each of the three-terminal surface-mount type solid electrolytic capacitors having the shapes of Example 1 and Comparative Example 1-2 was assembled using a conductive adhesive. Each of the anode terminals and the cathode terminals was disposed so that the silver plating surface faced the anode body side, and a conductive adhesive was applied to the adhesion portion and dried and solidified. A silver paste was used as the conductive adhesive. During this bonding, the amount of conductive adhesive applied for connecting the anode terminals of Example 1 and Comparative Example 1-2 was controlled, and the conductive adhesive was actually out of the connecting portions of each anode terminal. Samples were prepared by changing the covering area. Here, the actual coating amount of the conductive adhesive in each sample is made by changing the coating amount little by little, and after drying and solidifying, the prototype sample is cut and the cross section is observed to measure the covering area of the anode terminal It was calculated by doing. According to this method, for each of Example 1 and Comparative Example 1-2, the application amount at which the connection area at the anode terminal by the conductive adhesive becomes 20%, 40%, 60%, 80%, and 100%, respectively. Then, 12 samples under each condition were prepared. Since there are five conditions for each of Example 1 and Comparative Example 1-2, 60 samples were prepared.

  In each sample prepared as described above, the value of DC resistance between two anode terminals was measured. The results are shown in Table 1. In addition, although it is thought that there is some variation in the actual connection area in each sample, the variation is estimated to be 5% or less. The results shown in Table 1 are average values of 12 samples for each condition. The numerical values in Table 1 are relative values, and the case where the connection area is 100% in Example 1 is 1.0.

  In Table 1, when any one of the 12 samples was short-circuited between the anode terminal and the cathode terminal, it was determined to be inappropriate and indicated by “−” in the table. According to Table 1, in the case of Example 1 according to the present invention, no short circuit occurs even when the connection area is 100%, but in Comparative Example 1, when the connection area is 100%, in Comparative Example 2, When the connection area is 80% and 100%, a short circuit occurs in some samples. When the short circuit does not occur, the value of the direct current resistance decreases as the connection area increases, indicating that the resistance reduction in the three-terminal surface mount solid electrolytic capacitor has been realized. When the case of the same connection area is simply compared, the case of Comparative Example 1 seems to be superior to Example 1, but in the case of Comparative Example 1, a defect occurs when the connection area is 100%. Therefore, the minimum value of the DC resistance value is 1.2 when the connection area is 80%. As described above, in the present invention, a three-terminal surface mount type solid electrolytic capacitor having a relative value of 1.0 and the lowest DC resistance value is obtained as compared with Comparative Examples 1 and 2 of the conventional example. Can do.

(Example 2)
By using the method according to the present invention and the prior art, two-terminal surface mount type solid electrolytic capacitors were respectively produced and the connection resistances were compared. First, a two-terminal surface mount type solid electrolytic capacitor according to the present invention shown in FIG. When producing the surface mount type solid electrolytic capacitor of Example 2, the connection area at one anode terminal was changed, respectively, and the connection area at the anode terminal by the conductive adhesive was changed as in Example 1. Twelve samples under each condition of 20%, 40%, 60%, 80% and 100% were prepared. Each sample prepared was evaluated for a short circuit between the anode terminal and the cathode terminal, and it was confirmed that no short circuit occurred in all the samples.

  In a two-terminal surface mount solid electrolytic capacitor, since there is only one anode terminal, the value of the DC resistance between the anode terminals cannot actually be measured. However, since the configuration of the anode terminal portion is exactly the same as that of the three-terminal surface mount type solid electrolytic capacitor of Example 1, if it was possible to measure DC resistance, the same as in Example 1 was obtained. It is considered that a two-terminal surface mount type solid electrolytic capacitor having the lowest DC resistance value when the connection area is 100% can be realized.

  As described above, in the two-terminal or three-terminal surface mount solid electrolytic capacitor according to the present invention, the anode terminal has an L-shaped cross section, and the upright portion of the anode terminal serves as the cathode terminal. On the near side, the flat portion was arranged on the side far from the cathode terminal. This makes it possible to prevent the conductive adhesive used to connect and fix the anode body or anode conductive piece and the anode terminal to the cathode terminal side, thus limiting the amount of conductive adhesive used. There is no need. For this reason, in the connection of the facing surfaces of the anode terminal, anode body, and anode conducting piece, the entire area of the facing area can be used as a connecting surface by the conductive adhesive, thereby reducing the connection resistance in the solid electrolytic capacitor. Is possible. Further, the above description is for explaining the embodiment of the present invention, and does not limit the invention described in the scope of claims. Moreover, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim.

11, 31, 51, 71 Anode bodies 12, 32, 52, 72 Central portions 13, 33, 53, 73 Resist forming portions 14, 34, 54, 74 End portions 15, 35, 55, 75 Solid electrolyte layers 16, 36 , 56, 76 Graphite layers 17, 37, 57, 77 Silver electrode layers 18, 38, 58, 78 Resist layers 19, 39, 59, 79 Anode conductive pieces 20, 40, 60, 80 Anode terminals 21, 41, 61, 81 Cathode terminal 22, 23, 42, 43, 62, 63, 82, 83 Conductive adhesive 24, 44, 64, 84 Mold resin case 25, 45, 65 Protruding part 26, 46, 66, 86 Lid 27, 47, 67, 87 Adhesive

Claims (6)

An anode body made of a valve action metal having an enlarged surface, a dielectric layer formed on a part of the surface of the anode body, and a solid electrolyte layer and a cathode on the surface of the dielectric layer Formed bodies are respectively formed in this order, and a cathode terminal is connected to the cathode formed body through a conductor,
In addition, an anode conducting piece is connected to a part of the surface of the anode body other than the region where the dielectric layer is formed, and a conductor is connected to the anode conducting piece, and the anode conducting piece and A solid electrolytic capacitor in which an anode terminal is connected to the anode body via the conductor,
The anode terminal is composed of a metal body having an L-shaped cross section, which is composed of a combination of two flat plate-like structures of an upright portion and a flat portion that are orthogonal to each other, and the flat portion is The conductor is disposed in a direction parallel to the longitudinal direction of the anode body and connected to the anode conduction piece via the conductor, and the upright portion is disposed in a direction perpendicular to the longitudinal direction of the anode body. A surface mount type solid electrolytic capacitor, characterized in that it is connected to the anode conducting piece and the anode body via a pin, and is arranged so that the upright portion is located closer to the cathode terminal than the flat portion.   The surface mount type solid electrolytic capacitor according to claim 1, wherein the conductor is made of a conductive adhesive.   The surface mount type solid electrolytic capacitor according to claim 1, wherein an end portion of the upright portion of the anode terminal is in contact with the anode body.   The cathode forming body is composed of a graphite layer and a silver electrode layer, and the dielectric layer, the solid electrolyte layer, the graphite layer, and the silver electrode layer are respectively formed on a part of the surface of the anode body. 4. The surface mount type solid electrolytic capacitor according to claim 1, wherein the surface mount type solid electrolytic capacitor is formed in order.   1 cathode terminal and 2 anode terminals having a L-shaped cross section, and each electrode terminal is disposed at a position where the 1 cathode terminal is sandwiched between the 2 anode terminals. The three-terminal surface-mount type solid electrolytic capacitor according to any one of claims 1 to 4.   5. The device according to claim 1, further comprising: a cathode terminal and an anode terminal having an L-shaped cross section, and the electrode terminals are arranged in parallel. 6. Two-terminal surface mount type solid electrolytic capacitor.

Images