JP4790488B2 - Solid electrolytic capacitor - Google Patents

Description

  The present invention relates to a solid electrolytic capacitor provided with a porous sintered body of a valve action metal.

  FIG. 5 shows an example of a conventional solid electrolytic capacitor. The solid electrolytic capacitor X shown in the figure includes a porous sintered body 91 from which an anode wire 92 protrudes, and faces the circuit board S using mounting surfaces 96Aa and 96Ba of the anode terminal 96A and the cathode terminal 96B. It is configured to be mountable. The anode terminal 96A is electrically connected to the anode terminal 92 through the conductive member 96C. A dielectric layer 93 and a solid electrolyte layer 94 are stacked on the surface of the porous sintered body 91. The solid electrolyte layer 94 and the cathode terminal 96 </ b> B are joined by a conductor layer 95. At the base of the anode wire 92, a bleed-up preventing plate 97 is fitted. The spread prevention plate 97 is made of an insulating material such as a fluororesin, and has a hole 97a for allowing the anode wire 92 to pass therethrough. In the manufacturing process of the solid electrolytic capacitor X, the porous sintered body 91 on which the dielectric layer 93 is formed in order to form the solid electrolyte layer 94 is immersed in an aqueous manganese nitrate solution, for example. At this time, it is possible to avoid the manganese nitrate aqueous solution from being unduly attached to the anode wire 92 by the spread prevention plate 97. Thereby, it can prevent that the anode wire 92 and the solid electrolyte layer 94 conduct | electrically_connect.

  However, since the spread prevention plate 97 remains as a component of the solid electrolytic capacitor X, the volume of the solid electrolytic capacitor X increases by the amount of the spread prevention plate 97. In order to make the volume of the solid electrolytic capacitor X constant, the volume of the porous sintered body 91 must be reduced. There is a problem that the capacitance of the solid electrolytic capacitor X is reduced by the volume reduction of the porous sintered body 91. Further, in a state where the solid electrolytic capacitor X is mounted on the circuit board S, the bulge prevention plate 97 is located in the direction in which the circuit board S spreads with respect to the porous sintered body 91. For this reason, the mounting area of the solid electrolytic capacitor X is increased by the amount of the spread prevention plate 97. Therefore, high-density mounting on the circuit board S has been hindered.

JP 2001-358038 A

  The present invention has been conceived under the circumstances described above, and an object of the present invention is to provide a solid electrolytic capacitor that can be reduced in size and increased in capacity.

The solid electrolytic capacitor provided by the present invention includes a porous sintered body made of a valve metal, a dielectric layer and a solid electrolyte layer laminated on the surface of the porous sintered body, and the porous sintered body. An anode wire protruding from the plate , a plate-like anode terminal that is electrically connected to the anode wire and has a mounting surface for surface mounting, and is electrically connected to the solid electrolyte layer and is flush with the mounting surface of the anode terminal. A solid electrolytic capacitor comprising a plate-like cathode terminal having a mounted surface and a resin package covering at least a part of the porous sintered body, wherein the anode wire is formed from the porous sintered body. The anode terminal protrudes perpendicularly to the mounting surface and is connected to the surface of the anode terminal opposite to the mounting surface using a conductive paste, and the cathode terminal is connected to the solid electrolyte layer. Conductor covering The is conducting in the solid electrolyte layer through, between the above porous sintered body and the anode terminal, the insulating member made of fluorine resin surrounding at least a portion of the anode wire, the anode terminal It is characterized by being provided so as to straddle the surface opposite to the mounting surface and the surface opposite to the mounting surface of the cathode terminal .

According to such a configuration, when forming the solid electrolyte layer in the manufacturing process of the solid electrolytic capacitor, the aqueous solution or reaction solution for forming the solid electrolyte layer is prevented from soaking into the anode wire. In addition, the insulating member can be used. Further, in a state where the solid electrolytic capacitor is mounted on the circuit board, the insulating member is positioned on the circuit board side with respect to the porous sintered body, and There is no position in the direction in which the circuit board spreads. Therefore, it is possible to reduce the mounting area of the solid electrolytic capacitor on the circuit board. Further, according to such a configuration, when the porous sintered body to which the insulating member is attached is placed on the anode terminal and the cathode terminal in the manufacturing process of the solid electrolytic capacitor, the insulating member Contacts the anode terminal and the cathode terminal. For this reason, the porous sintered body is supported by the anode terminal and the cathode terminal through the insulating member, and the porous sintered body is unduly inclined with respect to the anode terminal and the cathode terminal. Can be prevented.

  In a preferred embodiment of the present invention, at least a portion of the insulating member located near the mounting surface of the anode terminal is exposed from the resin package. According to such a configuration, a part of the resin package can be replaced by the insulating member. Thereby, the volume of the resin package can be reduced, and the solid electrolytic capacitor can be miniaturized. Further, the volume of the porous sintered body can be increased without increasing the volume of the solid electrolytic capacitor, and the capacity of the solid electrolytic capacitor can be increased.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  1 and 2 show an example of a solid electrolytic capacitor according to the present invention. The solid electrolytic capacitor A of the present embodiment includes a porous sintered body 1, an anode wire 2, a dielectric layer 3, a solid electrolyte layer 4, a conductor layer 5, an anode terminal 6A, a cathode terminal 6B, a bleed-out prevention plate 7, In addition, a resin package 8 is provided and is configured to be surface-mounted on the circuit board S.

  The porous sintered body 1 is made of a valve action metal such as niobium or tantalum and has a structure in which a large number of pores are formed. In the present embodiment, the porous sintered body 1 has a rectangular parallelepiped shape. The porous sintered body 1 is produced, for example, by subjecting a fine powder of a valve action metal such as niobium or tantalum to pressure molding using a mold and then subjecting this molded body to a sintering treatment. By this sintering treatment, fine powders of the valve action metal are sintered, and the porous sintered body 1 having a large number of pores is formed.

  The anode wire 2 is made of a valve action metal such as niobium or tantalum, and a part of the anode wire 2 enters the porous sintered body 1. The anode wire 2 is an integral product in a state where a part of the anode wire 2 is intruded into the fine powder when the fine powder of the valve action metal described above is pressed. As shown in FIG. 1, the anode wire 2 protrudes toward the anode terminal 6A.

  The dielectric layer 3 is formed on the surface of the porous sintered body 1 and is made of an oxide of a valve action metal. The dielectric layer 3 covers the pores of the porous sintered body 1. The dielectric layer 3 is formed, for example, by subjecting the porous sintered body 1 to anodization in a state where the porous sintered body 1 is immersed in a chemical conversion solution of a phosphoric acid aqueous solution.

  The solid electrolyte layer 4 is laminated on the dielectric layer 3 and is formed so as to fill the pores of the porous sintered body 1. The solid electrolyte layer 4 is made of, for example, manganese dioxide or a conductive polymer. When the solid electrolytic capacitor A is used, charges are stored at the interface between the solid electrolyte layer 4 and the dielectric layer 3. For this reason, the capacitance of the solid electrolytic capacitor A can be increased as the area of the interface between the solid electrolyte layer 4 and the dielectric layer 3 is larger.

  The anode terminal 6A is a plate-like member made of, for example, Cu or Ni, and is joined to the tip of the anode wire 2 with, for example, a conductive paste (not shown). The surface located on the opposite side of the porous sintered body 1 in the anode terminal 6A is a mounting surface 6Aa. The mounting surface 6Aa is a part used for surface mounting the solid electrolytic capacitor A on the circuit board S, for example.

  The cathode terminal 6B is a plate-like member made of, for example, Cu or Ni, and is electrically connected to the solid electrolyte layer 4 by the conductor layer 5. The surface located on the opposite side of the porous sintered body 1 in the cathode terminal 6B is a mounting surface 6Ba. The mounting surface 6Ba is flush with the mounting surface 6Aa of the anode terminal 6A. The mounting surface 6Ba is used for surface mounting of the solid electrolytic capacitor A. As shown in FIG. 2, the anode terminal 6 </ b> A and the cathode terminal 6 </ b> B are arranged near both ends of the solid electrolytic capacitor A, and each has a rectangular shape whose width is slightly smaller than the width of the resin package 8. .

  The spread prevention plate 7 is a plate-like member made of, for example, a fluororesin, and is provided between the porous sintered body 1 and the anode terminal 6A as shown in FIG. The bleeding prevention plate 7 is an example of an insulating member referred to in the present invention. A hole 7 a is formed in the bleeding prevention plate 7. The hole 7a is a portion for fitting the spread preventing plate 7 to the anode wire 2 and has an inner diameter that allows the anode wire 2 to pass therethrough. As shown in FIG. 2, the spread prevention plate 7 has a dimension in plan view that is slightly smaller than the outer diameter dimension of the solid electrolytic capacitor A, and is shaped to straddle the anode terminal 6A and the cathode terminal 6B. ing. A portion between the anode terminal 6 </ b> A and the cathode terminal 6 </ b> B of the spill prevention plate 7 is exposed from the resin package 8.

  FIG. 3 shows a process of forming the solid electrolyte layer 4 in the manufacturing process of the solid electrolytic capacitor A. Prior to this step, the dielectric layer 3 is formed on the surface of the porous sintered body 1 with the anti-swelling plate 7 fitted in advance on the anode wire 2. The porous sintered body 1 is immersed in an aqueous solution 42 of manganese nitrate filled in a container 41, for example. At this time, the interface of the aqueous solution 42 stays on the spill-preventing plate 7 and does not contact the protruding portion of the anode wire 2. A relatively large surface tension is generated between the bleeding prevention plate 7 made of a fluororesin and the aqueous solution 42. Thereby, it is possible to prevent the aqueous solution 42 from being improperly spread onto the protruding portion of the anode wire 2. After the porous sintered body 1 is lifted from the aqueous solution 42, a firing process is performed. By repeating this operation, the solid electrolyte layer 4 can be formed on the dielectric layer 3. Even when the solid electrolyte layer 4 made of a conductive polymer is formed, the spill prevention plate 7 can prevent the reaction liquid for electrolytic polymerization or chemical polymerization from oozing into the anode wire 2.

  The resin package 8 is made of, for example, an epoxy resin, and protects the porous sintered body 1 as shown in FIG. The resin package 8 is molded using, for example, an epoxy resin material. As shown in FIG. 2, in the present embodiment, the mounting surfaces 6 </ b> Aa and 6 </ b> Ba of the anode terminal 6 </ b> A and the cathode terminal 6 </ b> B and a part of the anti-slip plate 7 are exposed from the resin package 8.

  Next, the operation of the solid electrolytic capacitor A will be described.

  According to the present embodiment, in the state where the solid electrolytic capacitor A is mounted on the circuit board S, the spread prevention plate 7 is positioned on the circuit board S side with respect to the porous sintered body 1. Unlike the present embodiment, in the configuration in which the spread prevention plate 7 is positioned in the direction in which the circuit board S spreads with respect to the porous sintered body 1, the circuit board S of the solid electrolytic capacitor is equivalent to the spread prevention plate 7. The mounting area becomes large. Such a thing hinders high-density mounting. In the solid electrolytic capacitor A, the spread prevention plate 7 does not increase the mounting area of the solid electrolytic capacitor A, and the mounting area of the solid electrolytic capacitor A is the same as that of the porous sintered body 1 and the resin package 8 covering it. It is possible to make the size as large as the thickness. Therefore, the mounting area of the solid electrolytic capacitor A can be reduced, and high-density mounting can be achieved.

  By exposing a part of the spread prevention plate 7, the circuit board S side portion of the porous sintered body 1 is covered with the spread prevention plate 7 instead of the resin package 8. For this reason, it is possible to reduce the volume of the resin package 8 by the amount of the squeezing prevention plate 7. This is suitable for reducing the size of the solid electrolytic capacitor A. Further, if the volume of the porous sintered body 1 is increased by the volume reduction of the resin package 8 corresponding to the spread prevention plate 7, the capacity of the solid electrolytic capacitor A can be increased without changing the volume. Can do.

  By setting the spread prevention plate 7 to straddle the anode terminal 6A and the cathode terminal 6B, the solid electrolytic capacitor A can be reliably and easily manufactured. FIG. 4 shows one process of manufacturing the solid electrolytic capacitor A. In this step, the porous sintered body 1 is placed on the frame 6 to be the anode terminal 6A and the cathode terminal 6B. Prior to this step, a spread prevention plate 7 is attached to the porous sintered body 1, and a dielectric layer 3 and a solid electrolyte layer 4 are formed. When the porous sintered body 1 is brought close to the frame 6, the spread prevention plate 7 comes into contact with the anode terminal 6A and the cathode terminal 6B. Therefore, the porous sintered body 1 is not supported by only one of the anode terminal 6A and the cathode terminal 6B, but is supported by both the anode terminal 6A and the cathode terminal 6B via the bleed-up prevention plate 7. Is done. Therefore, there is no fear that the porous sintered body 1 is unduly inclined with respect to the frame 6, and the porous sintered body 1 and the frame 6 can be reliably and easily joined.

  The solid electrolytic capacitor according to the present invention is not limited to the above-described embodiment. The specific configuration of each part of the solid electrolytic capacitor according to the present invention can be varied in design in various ways.

  The insulating member referred to in the present invention can be made of a resin material other than fluororesin, glass, or the like as long as it functions to prevent the aqueous solution or reaction solution from penetrating the anode wire when forming the solid electrolyte layer. It may be formed. In addition to the configuration in which the insulating member straddles the anode terminal and the cathode terminal, the insulating member may be configured not to overlap the cathode terminal. Further, the insulating member may be entirely covered with the resin package.

It is sectional drawing which shows an example of the solid electrolytic capacitor which concerns on this invention. It is a bottom view which shows an example of the solid electrolytic capacitor which concerns on this invention. It is sectional drawing which shows the process of forming a solid electrolyte layer in an example of the manufacturing method of the solid electrolytic capacitor shown in FIG. FIG. 4 is a cross-sectional view of a principal part showing a step of placing a porous sintered body on a frame in an example of the method for producing the solid electrolytic capacitor shown in FIG. 1. It is sectional drawing which shows an example of the conventional solid electrolytic capacitor.

Explanation of symbols

A Solid electrolytic capacitor S Circuit board 1 Porous sintered body 2 Anode wire 3 Dielectric layer 4 Solid electrolyte layer 5 Conductor layer 6A Anode terminal 6Aa Mounting surface 6B Cathode terminal 6Ba Mounting surface 7 Swelling prevention plate (insulating member)
7a hole 8 resin package

Claims (2)

A porous sintered body made of a valve metal,
A dielectric layer and a solid electrolyte layer laminated on the surface of the porous sintered body;
An anode wire protruding from the porous sintered body;
A plate-like anode terminal that is electrically connected to the anode wire and has a mounting surface for surface mounting;
A plate-like cathode terminal that is electrically connected to the solid electrolyte layer and has a mounting surface that is flush with the mounting surface of the anode terminal;
A resin package covering at least a part of the porous sintered body;
A solid electrolytic capacitor comprising:
The anode wire protrudes perpendicularly to the mounting surface of the anode terminal from the porous sintered body, and is connected to the surface of the anode terminal opposite to the mounting surface using a conductive paste. And
The cathode terminal is electrically connected to the solid electrolyte layer through a conductor layer covering the solid electrolyte layer,
Between the porous sintered body and the anode terminal, an insulating member made of a fluororesin that surrounds at least a part of the anode wire includes a surface opposite to the mounting surface of the anode terminal, and the cathode terminal A solid electrolytic capacitor characterized in that the solid electrolytic capacitor is provided so as to straddle the mounting surface and the surface on the opposite side .   2. The solid electrolytic capacitor according to claim 1, wherein at least a portion of the insulating member located near the mounting surface of the anode terminal is exposed from the resin package.

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