JP2006295075A - Capacitor element of solid electrolytic capacitor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an increase of capacity of a capacitor and occurrence of a failure in a capacitor element 1 which includes an anode chip 2 obtained by sintering porously a powder of a valve-function metal, an anode bar 3 whose one end is buried in the anode so that the bar extrudes from an edge surface 2a of the anode chip, a solid electrolytic layer 5 that is formed with a dielectric film 4 formed on the surface of the metal powder as a ground, and a cathode film 6 that is formed on the surface of the solid electrolytic layer. <P>SOLUTION: A groove 7 is provided at the root of the anode bar 3 for the anode chip 2 so as to enclose the surrounding of the anode bar. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a capacitor element used in a solid electrolytic capacitor made of a valve metal such as tantalum or niobium, and a manufacturing method thereof.

  Generally, a capacitor element used for the solid electrolytic capacitor is generally manufactured as described below.

  That is, first, as shown in FIG. 1, a valve metal powder such as tantalum is applied to a porous anode tip body 2, and a part of the anode rod 3 made of valve action metal is also placed in the anode tip body 2. After being molded to be embedded, it is sintered by heating to a high temperature.

  Next, as shown in FIG. 2, the anode tip body 2 is dipped in a chemical conversion solution B such as an aqueous phosphoric acid solution contained in a container A, and in this state, an anode current is applied to the anode tip body 2. By performing the oxidation treatment, a dielectric film 4 made of tantalum pentoxide or the like having a high insulating property is formed on the surface of each valve action metal powder in the anode tip body 2 and the anode wire 3 with respect to the anode tip body 2 is formed. A dielectric film 4 ′ made of tantalum pentoxide having a high insulating property is also formed on the surface of the length S portion at the base.

  Next, as shown in FIG. 3, the anode tip body 2 is dipped into the solid electrolyte aqueous solution D such as a manganese nitrate aqueous solution in a container C to the end surface 2a of the anode tip body 2 and pulled up. Thus, the solid electrolyte layer 5 made of manganese dioxide is formed on the surface of the dielectric layer 4 by repeating the heating and firing a plurality of times.

Next, as shown in FIG. 4, a cathode film 6 having a graphite film as a base and a silver or other metal film as an upper layer is formed on the surface of the anode tip body 2 except for its one end face 2a. A plurality of capacitor elements 1 are obtained.
JP 2003-142339 A

  However, in this manufacturing method, when the solid electrolyte layer 5 is formed, as shown in FIG. 3, the anode tip body 2 is placed in one end surface 2a of the anode tip body 2 in a solid electrolyte aqueous solution D such as a manganese nitrate aqueous solution. The portion where the solid electrolyte aqueous solution D does not form the dielectric film beyond the dielectric film 4 ′ at the base portion of the anode rod 3 along the surface of the anode rod 3 when the solid electrolyte aqueous solution D is dipped to the portion of The solid electrolyte layer 5 on the cathode side is in direct contact with the anode rod 3 on the anode side due to the soaking of the solid electrolyte aqueous solution D, and is electrically connected therebetween. There is a problem that many things occur.

  Moreover, the solid electrolyte layer formed by oozing over the dielectric film 4 'at the base of the anode rod 3 is fixed to the lead terminal made of a metal plate by welding or the like. There was a problem that greatly hindered.

  Further, in the conventional capacitor element, by increasing the burying length L of the anode rod 3 in the anode tip body 2, the pulling strength from the anode tip body 2 in the anode rod 3 can be improved, and the anode Since each metal powder is reliably bonded to the rod 3, the effective volume in the anode tip body 2, that is, the capacitor capacity is reduced by increasing the buried length L in the anode rod 3. There was a problem.

  The present invention has a technical problem to solve these problems.

In order to achieve this technical problem, the capacitor element of the present invention is as described in claim 1.
“An anode tip body formed by sintering a powder of valve action metal into a porous body, an anode rod having one end embedded in the anode tip body so as to protrude from one end face of the anode tip body, and the anode tip In a capacitor element comprising a solid electrolyte layer formed on the surface of a body with a dielectric film formed on the surface of the metal powder as a base, and a cathode film formed on the surface of the solid electrolyte layer,
A concave groove that surrounds the periphery of the anode rod is provided at the base of the anode tip body of the anode rod. "
It is characterized by that.

Further, the capacitor element of the present invention, as described in claim 2,
“When the valve action metal powder is sintered to be porous, the anode tip body, the anode rod embedded so as to protrude from the anode tip body, and the metal powder on the surface of the anode tip body In a capacitor element comprising a solid electrolyte layer formed with a dielectric film formed on the surface of the substrate as a base, and a cathode film formed on the surface of the solid electrolyte layer,
The anode rod is provided with a recessed groove that surrounds the anode rod at both the base portion of the anode tip body and the portion embedded in the anode tip body. "
It is characterized by that.

On the other hand, the manufacturing method of the present invention, as described in claim 3,
“The process of embedding and compacting the valve metal powder in a porous anode tip body and embedding a valve metal anode rod so as to protrude from the anode tip body,
Sintering an anode tip body comprising the anode rod;
Forming a dielectric film on the anode tip body by anodic oxidation, then forming a solid electrolyte layer by dipping into a solid electrolyte aqueous solution, and then forming a cathode film;
In a method of manufacturing a capacitor element comprising:
Prior to the step of compacting and forming the anode tip body, a step of providing a recessed groove surrounding the periphery of the base portion of the anode rod with respect to the anode tip body is provided. "
It is characterized by that.

Further, the manufacturing method of the present invention, as described in claim 4,
"The process of embedding and compacting the valve metal powder in a porous anode tip body and embedding a valve metal anode rod so as to protrude from the anode tip body,
Sintering an anode tip body provided with the anode rod;
Forming a dielectric film on the anode tip body by anodic oxidation, then forming a solid electrolyte layer by dipping into a solid electrolyte aqueous solution, and then forming a cathode film;
In a method of manufacturing a capacitor element comprising:
Prior to the step of solidifying the anode tip body, a recess that surrounds the periphery of both the base portion of the anode rod with respect to the anode tip body and the portion embedded in the anode tip body. Providing a groove. "
It is characterized by that.

Furthermore, the manufacturing method of the present invention, as described in claim 5,
“The process of embedding and compacting the valve metal powder in a porous anode tip body and embedding a valve metal anode rod so as to protrude from the anode tip body,
Sintering an anode tip body comprising the anode rod;
Forming a dielectric film on the anode tip body by anodic oxidation, then forming a solid electrolyte layer by dipping into a solid electrolyte aqueous solution, and then forming a cathode film;
In a method of manufacturing a capacitor element comprising:
Prior to the step of compacting and forming the anode tip body, a plurality of recessed grooves surrounding the anode rod material wire are formed on a base portion of the anode tip body and the anode tip body. And a step of cutting the material wire material for each of the anode rods. "
It is characterized by that.

  As described above, by providing a groove at the base of the anode tip body of the anode rod so as to surround the periphery of the anode rod, the solid electrolyte aqueous solution is applied to the surface of the anode rod when forming the solid electrolyte layer. Accordingly, it is possible to reliably prevent the anode rod from penetrating toward the tip of the anode rod by the recessed groove provided in the base portion.

  In other words, since the solid electrolyte aqueous solution can be surely prevented from penetrating beyond the dielectric film formed at the base portion of the anode rod, the incidence of defective products when forming the solid electrolyte layer When the anode bar is fixed to the lead terminal made of a metal plate by welding or the like, it can be reliably avoided that the solid electrolyte layer becomes an obstacle.

  Further, in addition to providing a recessed groove at the base of the anode tip body in the anode rod, a recessed groove is also provided in a portion to be embedded in the anode tip body, so that the anode tip body in the anode rod can be removed. In addition to improving the pulling strength of the anode rod, it is possible to reliably bond each metal powder to the anode rod. Therefore, the embedment length of the anode rod with respect to the anode tip body can be shortened and effective in the anode tip body. The volume, that is, the capacitance of the capacitor can be increased.

  In particular, in the manufacturing method, the anode rod is formed from the raw material wire by the method described in claim 5, and a groove is formed in each of the root portion of the anode rod with respect to the anode tip body and the portion embedded in the anode tip body. Therefore, the anode rod can be easily manufactured by providing a recessed groove at the important point, and the manufacturing cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 5 shows a material wire E for manufacturing the anode rod 3 in the capacitor element 1 shown in FIG. 4. The material wire E has a plurality of recessed grooves 7 surrounding the periphery thereof. The anode rod 3 is provided at a pitch interval P between the base portion of the anode tip body 2 and the portion embedded in the anode tip body 2.

  Each of the recessed grooves 7 can be provided by a method similar to the thread rolling of a bolt, or can be provided by a corrosion treatment.

  Next, as shown in FIG. 6, the anode rod 3 having a predetermined length W is cut from the material wire E.

  On the other hand, as shown in FIG. 7, the valve action metal powder G is placed in the molding hole F2 formed in the press die F1, with the bottom of the molding hole F2 closed by the lower press die F3. Fill.

  Next, as shown in FIG. 8, the upper press die F4 holding the anode rod 3 is pushed into the forming hole F2 in the press die F1, thereby solidifying and molding the porous anode tip body 2.

  At the time of this compacting, the anode rod 3 protrudes from the upper press die F4 by a predetermined embedding depth L with respect to the anode tip body 2 with respect to the upper press die F4, and one recessed groove in the anode rod 3 is formed. 7 is held at the base portion with respect to the anode tip body 2 and at least one other recessed groove 7 is located at a portion in the anode tip body 2, and in this state, the inside of the molding hole F2 is held. To push into.

  Accordingly, as shown in FIG. 9, at least one end portion of the anode rod 3 in the anode tip body 2 and one recessed groove 7 in the anode rod 3 are provided at the base portion of the anode tip body 2. One recessed groove 7 can be embedded in a state where it is located in each part of the anode tip body 2.

  Next, the anode tip body 2 is baked to be heated to a high temperature (for example, about 1500 ° C.) together with the anode rod 3 embedded in the anode tip body 2 to bond the metal powders to each other and to bond the metal powder to the anode rod 3. And combine.

  In this sintered state, at least one recessed groove 7 is present in the portion of the anode rod 3 embedded in the anode tip body 2, and the recessed groove 7 causes the anode rod 3 to The pull-out strength from the anode tip body 2 can be improved, and each metal powder can be securely bonded to the anode rod 3, so that the burying length L of the anode rod relative to the anode tip body can be increased accordingly. It can be made shorter than the case where the recessed groove is not provided.

  In the following, the capacitor element 1 is manufactured in the same manner as in the prior art.

  That is, as shown in FIG. 2, the anode tip body 2 is dipped in a chemical conversion solution B such as a phosphoric acid aqueous solution in a container A, and in this state, an anode current is applied to the anode tip body 2. By performing the oxidation treatment, a dielectric film 4 made of tantalum pentoxide or the like having a high insulating property is formed on the surface of each valve action metal powder in the anode tip body 2, and from one end face 2 a of the anode tip body 2. A dielectric film 4 ′ made of tantalum pentoxide having a high insulating property is also formed on the surface of the portion of the length dimension S at the base of the protruding anode wire 3.

  Next, when the anodic oxidation treatment for forming the dielectric layers 4 and 4 'is finished, the anode tip body 2 is replaced with a solid electrolyte aqueous solution such as a manganese nitrate aqueous solution placed in a container C as shown in FIG. During D, the dielectric layer in the anode tip body 2 is repeatedly dipped, pulled up and heated and fired a plurality of times (for example, about 10 times). A solid electrolyte layer 5 made of manganese dioxide is formed on the surface of 4.

  When the solid electrolyte layer 5 is formed, a concave groove 7 is provided at a base portion of the anode rod 3 with respect to the anode tip body 2, so that the anode tip body 2 is made into the solid electrolyte aqueous solution D. When dipping up to the end surface 2a of the anode tip body 2, the solid electrolyte aqueous solution D passes through the surface of the anode rod 3 and penetrates beyond the dielectric layer 4 '. It can be reliably prevented.

  Next, as shown in FIG. 4, a cathode film 6 having a graphite film as a base and a silver or other metal film as an upper layer is formed on the surface of the anode tip body 2 except for its one end face 2a. The capacitor element 1 is obtained.

It is a vertical front view which shows the conventional anode tip body. It is sectional drawing which shows the state which has formed the dielectric film in the said anode tip body. It is sectional drawing which shows the state which has formed the solid electrolyte layer in the said anode tip body. It is a vertical front view which shows the conventional capacitor | condenser element. It is a figure which shows the raw material wire for anode bars in this invention. It is a figure which shows the anode rod cut | disconnected from the said raw material wire. It is a longitudinal front view which shows the state before solid-molding to an anode tip body. It is a vertical front view which shows the state currently hardened and molded to the anode tip body. It is a vertical front view which shows the anode chip | tip body compacted in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Anode chip body 3 Anode rod 4 Dielectric film 5 Solid electrolyte layer 6 Cathode film 7 Recessed groove E Material wire for anode rod

Claims (5)

An anode tip body formed by sintering a powder of valve action metal into a porous body, an anode rod having one end embedded in the anode tip body so as to protrude from one end surface of the anode tip body, and the anode tip body A capacitor element comprising a solid electrolyte layer formed on the surface of the metal powder with a dielectric film formed on the surface of the metal powder as a base, and a cathode film formed on the surface of the solid electrolyte layer;
A capacitor element in a solid electrolytic capacitor, wherein a concave groove is provided at a base portion of the anode rod with respect to the anode tip body so as to surround the anode rod. When the valve action metal powder is sintered to be porous, an anode tip body, an anode rod embedded so as to protrude from the anode tip body, and the metal powder on the surface of the anode tip body. In a capacitor element comprising a solid electrolyte layer formed with a dielectric film formed on the surface as a base, and a cathode film formed on the surface of the solid electrolyte layer,
The anode rod is provided with a recessed groove so as to surround the anode rod in both the base portion of the anode tip body and the portion embedded in the anode tip body. Capacitor elements in solid electrolytic capacitors. A step of embedding and compacting a valve-acting metal powder in a porous anode tip body and embedding a valve-acting metal anode rod so as to protrude from the anode tip body;
Sintering an anode tip body comprising the anode rod;
Forming a dielectric film on the anode tip body by anodic oxidation, then forming a solid electrolyte layer by dipping into a solid electrolyte aqueous solution, and then forming a cathode film;
In a method of manufacturing a capacitor element comprising:
Before the step of solidifying and forming the anode tip body, a step of providing a recessed groove surrounding the periphery of the anode rod at the base portion of the anode tip body is provided. A method for manufacturing a capacitor element in a solid electrolytic capacitor. A step of embedding and compacting a valve-acting metal powder in a porous anode tip body and embedding a valve-acting metal anode rod so as to protrude from the anode tip body;
Sintering an anode tip body comprising the anode rod;
Forming a dielectric film on the anode tip body by anodic oxidation, then forming a solid electrolyte layer by dipping into a solid electrolyte aqueous solution, and then forming a cathode film;
In a method of manufacturing a capacitor element comprising:
Prior to the step of solidifying the anode tip body, a recess that surrounds the periphery of both the base portion of the anode rod with respect to the anode tip body and the portion embedded in the anode tip body. The manufacturing method of the capacitor | condenser element in a solid electrolytic capacitor characterized by providing the process of providing a groove | channel. A step of embedding and compacting a valve-acting metal powder in a porous anode tip body and embedding a valve-acting metal anode rod so as to protrude from the anode tip body;
Sintering an anode tip body comprising the anode rod;
Forming a dielectric film on the anode tip body by anodic oxidation, then forming a solid electrolyte layer by dipping into a solid electrolyte aqueous solution, and then forming a cathode film;
In a method of manufacturing a capacitor element comprising:
Prior to the step of compacting and forming the anode tip body, a plurality of recessed grooves surrounding the anode rod material wire are formed on a base portion of the anode tip body and the anode tip body. A method of manufacturing a capacitor element in a solid electrolytic capacitor, comprising: a step of providing a pitch interval between a portion embedded in the capacitor and a step of cutting the material wire for each anode rod.

Images