JP4896660B2 - Solid electrolytic capacitor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a solid electrolytic capacitor including a porous sintered body made of a valve metal such as tantalum or niobium and a method for manufacturing the same.

  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. A dielectric layer 93 and a solid electrolyte layer 94 are stacked on the surface of the porous sintered body 91. An insulating resin 97 made of, for example, a fluororesin is fitted at the base of the anode wire 92. The porous sintered body 91 is sealed with a resin package 98. The end surface 98a of the resin package 98 has a tapered surface so that the resin package 98 can easily come out of the mold during molding. The anode terminal 96A is electrically connected to the anode wire 92 through the conducting member 96C. The solid electrolyte layer 94 and the cathode terminal 96 </ b> B are joined by a conductor layer 95. The solid electrolytic capacitor X is configured to be surface-mountable on, for example, a circuit board using the anode terminal 96A and the cathode terminal 96B. In order to increase the capacitance of the solid electrolytic capacitor X, it is effective to increase the volume of the porous sintered body 91.

  However, in a circuit board on which the solid electrolytic capacitor X is mounted, electronic components such as the solid electrolytic capacitor X are mounted with high density. For this reason, the solid electrolytic capacitor X is also required to be further downsized. A volume obtained by removing the volume of the resin package 98 from the volume allowed for the solid electrolytic capacitor X is the size allowed for the porous sintered body 91. The resin package 98 needs to have a size that can sufficiently cover the portion of the anode wire 92 that protrudes from the porous sintered body 91 and the conductive member 96C. Further, since the end surface 98a is a tapered surface, portions of the resin package 98 that are in contact with, for example, the anode terminal 96A and the cathode terminal 96B are considerably thicker than the minimum necessary thickness for protecting the porous sintered body 91. turn into. Therefore, it is difficult to enlarge the porous sintered body 91 while reducing the size of the solid electrolytic capacitor X.

JP 2001-358038 A

  The present invention has been conceived under the circumstances described above, and it is an object of the present invention to provide a solid electrolytic capacitor capable of increasing the capacity while reducing the size and a method for manufacturing the same. .

The solid electrolytic capacitor provided by the first aspect of the present invention includes a porous sintered body made of a valve metal, an anode wire protruding from the porous sintered body, and a surface of the porous sintered body. A solid comprising a laminated dielectric layer and solid electrolyte layer, a resin package for sealing the porous sintered body, an anode terminal connected to the anode wire, and a cathode terminal connected to the solid electrolyte layer In the electrolytic capacitor, an end surface of the anode wire facing the protruding direction and an end surface of the resin package facing the protruding direction are flush with each other, and the end surface of the anode wire and the resin package The end face is parallel to the end face of the porous sintered body facing the protruding direction, the anode terminal covers the end face of the anode wire, and the resin package It is provided in a region extending from the end surface to the side surface along the protruding direction, is spaced from the porous sintered body, and has a ring shape that covers a portion near the end surface of the anode wire. It is provided with an insulating resin that is flush with the end face and the end face of the resin package and has an end face interposed therebetween, and the solid electrolyte layer is more porous sintered than the insulating resin. It is characterized by being formed in a region close to the body.

  According to such a structure, the thickness of the part which covers the said end surface of the said porous sintered compact among the said resin packages can be made uniform. If the thickness of this part of the resin package is set to a minimum necessary thickness for protecting the porous sintered body, the resin package is unnecessary except for the part for protecting the porous sintered body. It is possible to reduce the important part. Therefore, the solid electrolytic capacitor can be reduced in size and capacity.

The method of manufacturing a solid electrolytic capacitor provided by the second aspect of the present invention includes a step of forming a porous sintered body provided such that an anode wire protrudes in a direction perpendicular to an end surface, and the porous Forming a ring-shaped insulating resin that is separated from the sintered body and covers a part of the anode wire in the longitudinal direction; forming a dielectric layer on the surface of the porous sintered body; and A step of forming a solid electrolyte layer on the body layer, a step of forming a resin package for sealing the porous sintered body and the insulating resin and at least a part of the anode wire, and the porous sintered body. Cutting the resin package, the insulating resin, and the anode wire in parallel with the end surface of the resin package, and conducting the anode wire of the resin package from the end surface of the anode wire and the insulating resin by a conductor film. By covering the area over the side surface along the direction in which Ya is projected, it is characterized by comprising a step of forming an anode terminal.

  According to such a configuration, the resin package can be easily pulled out from the mold by forming an end surface having a tapered surface on the resin package before the cutting step. On the other hand, after the cutting step, the resin package is formed with an end surface perpendicular to the direction in which the anode wire protrudes. This is suitable for reducing the size and increasing the capacity of the solid electrolytic capacitor manufactured by the above manufacturing method.

  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.

  FIG. 1 shows an example of a solid electrolytic capacitor according to the present invention. The solid electrolytic capacitor A of this 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, an insulating resin 7, and a resin. A package 8 is provided and is configured to be surface-mounted on, for example, a circuit board.

  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. The porous sintered body 1 has an end face 1Ab. An anode wire 2 protrudes from the end face 1a. Each end face 1Ab is perpendicular to the direction x from which the anode wire 2 protrudes.

  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 from the end face 1a. The anode wire 2 has an end face 2a that is perpendicular to the direction x.

  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 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. The solid electrolyte layer 4 is covered with a conductor layer 5 made of, for example, a graphite layer and a silver layer.

  The insulating resin 7 has a ring shape made of, for example, a fluororesin, and surrounds the tip portion of the anode wire 2. The insulating resin 7 is for preventing the solution for forming the solid electrolyte layer 4 from unreasonably oozing up the anode wire 2. The end surface 7 a of the insulating resin 7 is flush with the end surface 2 a of the anode wire 2.

  The resin package 8 is made of, for example, an epoxy resin and is for protecting the porous sintered body 1. The resin package 8 has end faces 8a and 8b and a side face 8c. The end surface 8 a is flush with the end surface 2 a of the anode wire 2 and the end surface 7 a of the insulating resin 7. The end faces 8a and 8b are both perpendicular to the direction x. That is, the end surface 1 a of the porous sintered body 1, the end surface 2 a of the anode wire 2, and the end surface 8 a of the resin package 8 are parallel to each other. Moreover, the end surface 1b of the porous sintered body 1 and the end surface 8b of the resin package 8 are parallel to each other. The side surface 8c is a surface extending along the direction x and is perpendicular to the end surfaces 8a and 8b.

  The anode terminal 6A is made of, for example, a solder plating layer, and is used for surface mounting the solid electrolytic capacitor A on, for example, a circuit board. The anode terminal 6A covers the end surface 2a of the anode wire 2 and the end surface 7a of the insulating resin 7. Thereby, the anode terminal 6 </ b> A is electrically connected to the anode wire 2. The anode terminal 6 </ b> A covers a region extending from the end surface 8 a to the side surface 8 c of the resin package 8.

  The cathode terminal 6B is made of, for example, a solder plating layer, and is used for surface mounting the solid electrolytic capacitor A on, for example, a circuit board. The cathode terminal 6B covers a region extending from the end surface 8b to the side surface 8c of the resin package 8. The cathode terminal 6B is electrically connected to the conductor layer 5 via the conductive member 61B. The conducting member 61B is made of, for example, Cu or Ni.

  Next, a method for manufacturing the solid electrolytic capacitor A will be described below with reference to FIGS.

  First, as shown in FIG. 2, the porous sintered body 1 provided so that the anode wire 2 'protrudes is prepared. The porous sintered body 1 is manufactured by, for example, pressure-molding a fine powder of a valve action metal such as niobium or tantalum and then subjecting this compact 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 an integrated product in a state in which a part of the anode wire 2 ′ is intruded into the fine powder when the fine powder of the valve action metal is pressed. An insulating resin 7 is formed on the anode wire 2 'using, for example, a fluororesin paste. Next, the dielectric layer 3 is formed on the surface 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.

  Then, the porous sintered body 1 on which the dielectric layer 3 is formed is dipped in, for example, an aqueous manganese nitrate solution 40 shown in the figure. At this time, the interface of the aqueous solution 40 is set so as not to exceed the insulating resin 7. A relatively large surface tension is generated between the insulating resin 7 made of fluororesin and the aqueous solution 40. Thereby, it is possible to prevent the aqueous solution 40 from being improperly drawn into the protruding portion of the anode wire 2 ′. After the porous sintered body 1 is lifted from the aqueous solution 40, a baking treatment 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 insulating resin 7 can prevent the reaction liquid for electrolytic polymerization or chemical polymerization from oozing up to the anode wire 2 ′.

  Next, as shown in FIG. 3, the porous sintered body 1 is held by a frame 61 '. The frame 61 'is a plate-like member made of, for example, Cu or Ni, and has an anode side support portion 61A' and a cathode side support portion 61B '. A support member 62 is used to support the anode wire 2 by the anode side support portion 61A '. By using the support member 62, it is possible to prevent the porous sintered body 1 from being unduly inclined. On the other hand, graphite and silver paste are applied to the solid electrolyte layer 4 formed on the porous sintered body 1. And the part which apply | coated the said graphite and silver paste is joined with respect to cathode side support part 61B '. When the graphite and silver paste are cured, the conductor layer 5 is formed.

  Next, the resin package 8 ′ is molded while the porous sintered body 1 is supported by the frame 61 ′. At this time, both end surfaces 8a 'and 8b' of the resin package 8 'are tapered. Thereby, the resin package 8 'can be easily extracted from the mold used for the molding.

  After forming the resin package 8 ', the resin package 8' is cut along the cut surface CL shown in the drawing. The two cut surfaces CL are perpendicular to the direction x. A cutting line CL on the right side in the drawing crosses the insulating resin 7. The cutting line CL on the left side in the drawing is located between the porous sintered body 1 and the end face 8b '. By performing cutting along these cutting lines CL, an intermediate product shown in FIG. 4 is obtained. This intermediate product includes a resin package 8. End faces 8a and 8b that are perpendicular to the direction x are formed in the resin package 8 by the above-described cutting. In addition, an end surface 2 a is formed on the anode terminal 2, and an end surface 7 a is formed on the insulating resin 7. A part of the cathode side support portion 61B 'shown in FIG. 3 becomes a conducting member 61B. Thereafter, the solid electrolytic capacitor A shown in FIG. 1 is obtained by performing solder plating on the intermediate product.

  Next, the operation of the solid electrolytic capacitor A and its manufacturing method will be described.

  According to this embodiment, as shown in FIG. 1, the end surface 1a of the porous sintered body 1 and the end surface 8a of the resin package 8 are parallel to each other. For this reason, it is possible to make the thickness of the part which covers the end surface 1a among the resin packages 8 uniform. If the thickness of this part is the minimum necessary thickness for protecting the porous sintered body 1, an unnecessary part other than the part necessary for protecting the porous sintered body 1 in the resin package 8. Can be reduced. Therefore, the relative size of the porous sintered body 1 with respect to the solid electrolytic capacitor A can be increased, and the solid electrolytic capacitor A can be reduced in size and capacity.

  The structure in which the end surface 2a of the anode wire 2 exposed from the resin package 8 and the anode terminal 6A are in contact with each other, for example, in comparison with the structure for electrically connecting the anode wire 92 and the anode terminal 62A in the configuration shown in FIG. This is advantageous in reducing the size of the solid electrolytic capacitor A.

  By causing the anode terminal 6A to wrap around the side surface 8c of the resin package 8, it is possible to appropriately surface mount the solid electrolytic capacitor A on, for example, a circuit board using a portion of the anode terminal 6A that covers the side surface 8c. .

  In the present embodiment, the end surface 1b of the porous sintered body 1 and the end surface 8b of the resin package 8 are parallel to each other. For this reason, it is possible to make the thickness of the part which covers the end surface 1b among the resin packages 8 into minimum thickness required in order to protect the porous sintered compact 1. FIG. Thereby, size reduction and capacity increase of the solid electrolytic capacitor A can be further promoted.

  As shown in FIG. 3, the end surfaces 8a 'and 8b' of the resin package 8 'formed in the manufacturing process of the solid electrolytic capacitor A have tapered surfaces. Thereby, the resin package 8 'can be easily extracted from the mold. On the other hand, by cutting the resin package 8 ′ along the two cut surfaces CL, the end surfaces 8 a and 8 b of the resin package 8 are respectively parallel to the end surface 1 Ab of the porous sintered body 1. Therefore, according to the manufacturing method described above, it is possible to rationally reduce the size and increase the capacity of the solid electrolytic capacitor A while allowing the resin package 8 'to be easily extracted from the mold in the manufacturing process.

  The solid electrolytic capacitor and the manufacturing method thereof according to the present invention are not limited to the embodiment described above. The specific configuration of the solid electrolytic capacitor and the manufacturing method thereof according to the present invention can be varied in design in various ways.

It is sectional drawing 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. 3 is a cross-sectional view showing a state where a resin package is formed in an example of the method for manufacturing the solid electrolytic capacitor shown in FIG. It is sectional drawing which shows the state which cut | disconnected the resin package in an example of the manufacturing method of the solid electrolytic capacitor shown in FIG. It is sectional drawing which shows an example of the conventional solid electrolytic capacitor.

Explanation of symbols

A Solid electrolytic capacitor CL Cut surface x (protrusion) direction 1 Porous sintered body 1Ab End surface 2 Anode wire 2a End surface 3 Dielectric layer 4 Solid electrolyte layer 5 Conductor layer 6A Anode terminal 6B Cathode terminal 7 Insulating resin 8 Resin package 8a End face 40 Solution 61 ′ Frame 61A ′ Anode side support portion 61B ′ Cathode side support portion 61B Conducting member

Claims (2)

A porous sintered body made of a valve metal,
An anode wire protruding from the porous sintered body;
A dielectric layer and a solid electrolyte layer laminated on the surface of the porous sintered body;
A resin package for sealing the porous sintered body;
An anode terminal conducting to the anode wire;
A cathode terminal conducting to the solid electrolyte layer;
A solid electrolytic capacitor comprising:
The end surface facing the protruding direction of the anode wire and the end surface facing the protruding direction of the resin package are flush with each other,
The end face of the anode wire and the end face of the resin package are parallel to the end face of the porous sintered body facing the protruding direction,
The anode terminal covers the end surface of the anode wire and is provided in a region extending from the end surface to the side surface along the protruding direction in the resin package.
The ring-like shape is spaced apart from the porous sintered body and covers the portion near the end face of the anode wire, and is flush with the end face of the anode wire and the end face of the resin package, and It has an insulating resin having an end surface interposed between them,
The solid electrolytic capacitor, wherein the solid electrolyte layer is formed in a region closer to the porous sintered body than the insulating resin. Forming a porous sintered body provided such that the anode wire protrudes in a direction perpendicular to the end face;
Forming a ring-shaped insulating resin that is separated from the porous sintered body and covers a part of the anode wire in the longitudinal direction;
Forming a dielectric layer on the surface of the porous sintered body;
Forming a solid electrolyte layer on the dielectric layer;
Forming a resin package for sealing the porous sintered body and the insulating resin and at least a part of the anode wire;
Cutting the resin package, the insulating resin, and the anode wire in parallel with the end face of the porous sintered body;
A step of forming an anode terminal by covering a region extending from the end face of the anode wire and the insulating resin to a side surface of the resin package along a direction in which the anode wire protrudes with a conductor film. A method for manufacturing a solid electrolytic capacitor.

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