JP2001023871A - Structure of capacitor element of solid electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sharply reduce loading in porosity in the external face to a large extent by forming a chip with its shape tapered off from one end face to the other end face, chamfering the corner formed by the external face and the other end face of the chip, while applying insulation resin on an area corresponding to the chamfered face. SOLUTION: A chip is formed hard with a taper from one end face 17a' to the other end face 17b'. An inclination angle of the external face in a taper of the chip 17' is set so that a diameter of a combination formed by the chip 17' and a cathode side electrode film 19' at the one end face side 17a' is larger than that at the other end face 17b'. A chamfered face 17e' is formed on the external face 17c' and the other end face 17b' except the one end face 17a' out of all the surface and an insulation resin 20 is applied on the other end face 17b' after the cathode side electrode film 19' is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a capacitor element in a solid electrolytic capacitor such as tantalum or aluminum.

[0002]

2. Description of the Related Art In general,
For example, Japanese Patent Application Laid-Open No.
JP-A-220922 and the like, and as shown in FIGS. 13 and 14, a capacitor made of a sintered metal chip piece 2 and an anode rod 3 protruding from one end face 2a of the chip piece 2. The element 1 is connected to a pair of left and right lead terminals 4.
5, the anode rod 3 of the capacitor element 1 is disposed so as to be fixed to one lead terminal 4 by welding or the like, and the cathode formed on at least the outer peripheral surface 2 c of the chip piece 2 of the capacitor element 1. While the other lead terminal 5 is connected to the side electrode film 6, a solid electrolytic capacitor 100 in which these are entirely packaged in a synthetic resin mold part 7 is disclosed in, for example, JP-A-2-105513. As shown in FIG. 15, a capacitor element 1 including a chip 2 made of a sintered body of metal powder and an anode rod 3 protruding from the chip 2 is connected to a pair of left and right lead terminals 4, 5. In between, the anode bar 3 of the capacitor element 1 is disposed so as to be fixed to one lead terminal 4 by welding or the like, and the chip piece 2 of the capacitor element 1 is provided.
A cathode-side electrode film 6 formed on at least the outer peripheral surface 2c of
The other lead terminal 5 is connected via a safety fuse wire 8 which is blown by an overcurrent or a rise in temperature, and the whole of these is connected to a synthetic resin molded part 7.
And a solid electrolytic capacitor 200 with a safety fuse, which is packaged as a package.

[0003] The lead terminals 4 and 5 are bent to the back side of the molded part 7 after the molded part 7 is formed, as shown by a two-dot chain line.
The safety fuse wire 8 is coated with an elastic resin 8a such as a silicone resin.

These solid electrolytic capacitors 100, 20
When manufacturing the capacitor element 1 used for 0,
First, as shown in FIG. 16, a metal powder such as tantalum is
After a part of a metal anode rod 3 made of tantalum or the like is buried in a porous chip piece 2 having a square cross section, a circular cross section, an elliptical cross section, or the like, the chip piece 2 is compacted and molded, and then sintered. Then, as shown in FIG. 17, this porous chip piece 2 is
By immersing in a chemical solution such as a phosphoric acid aqueous solution A, a direct current is applied while the chemical solution such as the phosphoric acid aqueous solution A is infiltrated into the inside of the chip piece 2 to perform anodic oxidation.
A dielectric film 9 such as tantalum pentoxide is formed on the surface of each metal powder in the chip piece 2 and a part of the surface of the anode bar 3.

Next, the chip piece 2 which has completed the step of forming the dielectric film 9 of tantalum pentoxide or the like is
As shown in (2), the one end face 2a of the chip piece 2 is immersed in the manganese nitrate aqueous solution B until the end surface 2a does not become lower than the liquid level of the manganese nitrate aqueous solution B. The solid electrolyte layer 6a made of a metal oxide such as manganese dioxide is formed on the surface of the dielectric film 9 such as tantalum pentoxide by repeating a plurality of times of infiltration, withdrawal and firing.

A metal film such as silver or nickel is formed on the surface of the solid electrolyte layer 6a of the chip piece 2 with a graphite film as a base, thereby forming a metal film on the chip piece 2 as shown in FIG. A method of forming the cathode-side electrode film 6 on the outer peripheral surface 2c and the other end surface 2b is adopted.

However, the conventional solid electrolytic capacitor 10
0, 200, the diameter dimension d0 of the chip piece 2 in the capacitor element 1 (however, when the cross section is rectangular as shown in the figure, the diameter dimension is the length of one side or the other side thereof. When the cross-section is circular, the diameter is obtained, and when the cross-section is elliptical, the diameter in the major axis direction or the minor axis direction is applied. Since the outer peripheral surface 2c is configured to be parallel to the axis 2d of the chip piece 2 by setting the same dimensions over the end surface 2b, the following problem arises.

That is, when forming the solid electrolyte layer 6a of the metal oxide such as manganese dioxide in the electrode film 6 on the cathode side with respect to the chip piece 2, when the chip piece 2 is pulled up from the manganese nitrate aqueous solution, The aqueous solution of manganese nitrate that has permeated into the chip 2
The thickness of the cathode-side electrode film 6 formed by forming a graphite film and a metal film on the solid electrolyte layer 6a by hanging down toward the other end 2b of the As shown in FIG. 19, since the thickness gradually increases toward the other end 2b, the shape of the chip piece 2 is changed to the diameter dimension d0 as in the conventional case.
Is the same dimension from one end surface 2a to the other end surface 2c of the chip piece 2 and the outer peripheral surface 2c is configured to be parallel to the axis 2d, the chip piece 2 and the cathode-side electrode film 6 The maximum diameter d0max at the lower end of the combined body of the above is larger than the diameter at one end of the combined body of the chip piece 2 and the cathode side electrode film 6, so that the cathode side electrode is Membrane 6
As shown in FIG. 19, the shape of the combined body after the formation of is formed to swell from one end to the other end.

On the other hand, when the anode rod 3 protruding from the chip piece 2 of the capacitor element 1 is fixed to one of the lead terminals 4 by welding or the like, the chip piece 2 of the capacitor element 1 and the cathode side electrode film are fixed. 20, the axis 2d is inclined upward by an appropriate angle α1, or the axis 2d is inclined downward by an appropriate angle α2 due to the bending of the anode rod 3 or the like, as shown in FIG. In addition to the above, as shown in FIG. 21, the bending of the anode bar 3 or the like also causes an installation error such that the axis 2d is inclined by β1 and β2 in the left-right direction.

Therefore, when the shape of the combined body after the cathode-side electrode film 6 is formed on the chip piece 2 is a shape bulging from one end to the other end as described above. Are inclined angles α1, α2 in the vertical direction.
Due to the mounting error of the inclination angles β1 and β2 in the left and right directions, the cathode side electrode film 6 formed on the outer peripheral surface 2c of the chip piece 2
And the thickness dimensions T1 and T2 of the mold portion 7 at this portion are extremely thin, or the cathode-side electrode film 6 formed on the outer peripheral surface 2b of the chip piece 2 is Lower surface 7b of mold section 7
And the other lead terminal 5 or the safety fuse wire 8 connected to the cathode-side electrode film 6 is exposed on the upper surface 7a of the mold portion 7 and the cathode formed on the outer peripheral surface 2b of the chip piece 2 Since the side electrode film 6 is exposed on the left and right side surfaces 7c and 7d of the molded portion 7, defective products are frequently generated when the molded portion 7 is molded.

For this reason, in the prior art, the overall diameter d0 of the combined body of the chip piece 2 and the cathode-side electrode film 6 is reduced in order to reduce the incidence of defective products during the molding of the mold section 7. The thickness of the cathode-side electrode film 6 formed on the outer peripheral surface 2c of the chip piece 2 is reduced in advance by the thickness from the one end to the other end of the chip piece 2 as described above. Since it must be configured, there is a problem that increase in the capacity of the capacitor element is prevented.

In the manufacturing process of the capacitor element 1, a metal powder such as tantalum is
Conventionally, when a part of the anode rod 3 is buried in the chip piece 2 and compacted, the conventional method is shown in FIGS.
The method shown in FIG.

That is, as shown in FIG.
In a state in which a vertically movable lower forming die E is inserted into a lower part of the forming hole D, a metal powder F is filled, and then, as shown in FIG. At the same time, the upper mold G formed by sandwiching the anode rod 3 from both the left and right sides is pushed into the upper part of the molding hole D, and at the same time, the lower mold E is pushed into the lower part of the molding hole D. The metal powder F is compacted on the chip piece 2 so as to embed a part of the anode rod 3 in the chip piece 2, and then, as shown in FIG. While being pulled out from the inside, the lower molding die E is further pushed into the molding hole D, so that the compacted chip piece 2 is extruded from the molding hole D by the pushing of the lower molding die E. I try to die.

However, in this conventional compacting method, the molding die C is used to make the outer peripheral surface 2c of the chip piece 2 parallel to the axis 2d of the chip piece 2.
Is formed as a so-called parallel hole in which the inner peripheral surface of the forming hole D is parallel to the axis, as described below. Since the molding hole D is a so-called parallel hole as described above, the porous chip piece 2 compacted and molded in the molding hole D is pushed into the molding hole D by pushing the lower molding die E. The outer peripheral surface 2c of the chip piece 2 is strongly rubbed by the convex portion of the unevenness of the surface roughness existing on the inner surface of the molding hole D when the die piece 2 is punched out from the die. Will be clogged, in other words, porous clogging will occur on the outer peripheral surface 2c of the chip piece 2.

When the solid electrolyte layer 6a made of a metal oxide such as manganese dioxide is formed on the chip piece 2 due to the clogging occurring on the outer peripheral surface 2c, the aqueous solution of manganese nitrate is sufficiently introduced into the inside. In addition to being unable to penetrate into the manganese nitrate aqueous solution, the gas releasing property generated during baking after the permeation of the manganese nitrate aqueous solution is reduced, the formation of the solid electrolyte layer 6a becomes incomplete,
The dielectric loss in the capacitor element increases, leading to a decrease in performance, and an increase in the rate of defective products, leading to an increase in cost. . As the metal powder is compacted with a strong force, the density of each particle inside the chip piece 2 increases, and the capacity of the capacitor element can be increased. However, in the conventional compacting method, As described above, clogging occurs on the outer peripheral surface 2c of the chip piece 2 due to the unevenness of the surface roughness existing on the inner surface of the forming hole D, and the clogging is performed by hardening with a strong force. Since the pressing force at the time of compacting the metal powder cannot be increased due to the increase, the particle density cannot be increased, and the capacity per volume of the chip piece 2 is low. . When the porous chip piece 2 compacted and formed in the molding hole D of the molding die C is punched out from the molding hole D by pushing the lower molding die E, the molding hole is removed. Since the inner surface of D is severely rubbed by the chip pieces 2, the abrasion thereof is large, and the durability of the mold C is low. There was a problem to say.

An object of the present invention is to provide a capacitor element structure that solves these problems.

[0017]

Means for Solving the Problems In order to achieve this technical object, the structure of the capacitor element according to the present invention comprises a chip piece obtained by sintering a metal powder, an anode rod protruding from one end face of the chip piece, In a capacitor element for a solid electrolytic capacitor comprising a cathode-side electrode film formed on a portion of the outer peripheral surface of the chip piece excluding the one end face, the chip piece is moved from one end face to the other end face of the chip piece. The taper is formed in a tapered body, and the inclination angle of the outer peripheral surface of the tapered body is set at the same value as the diameter of the combined body of the chip piece and the cathode-side electrode film formed on the outer periphery in the portion of the other end surface. It is set so as not to be larger than the end face portion, and further, a chamfered face is provided at a corner between the outer peripheral face and the other end face of the chip piece, while the cathode side electrode is provided. And characterized in that Nurigi insulating resin portion corresponding to the chamfered surface of the. "It is intended.

[0018]

As described above, since the chip piece of the capacitor element is formed in a tapered body tapering from one end face to the other end face of the chip piece, the chip piece is formed into a mold for molding in a mold. In the hole, when the first molding die and the second molding die are pressed into the molding hole for compaction molding, the molding hole is tapered from one end to the other end of the molding hole. The tapered hole becomes a tapered hole, and the tapered chip piece after compaction molding is further pushed into the first molding die, so that the outer peripheral surface of the chip piece has irregularities of surface roughness existing on the inner surface of the tapered molding hole. Without being rubbed by the convex part,
Because it will immediately leave the inner surface of the molding hole,
It is possible to greatly reduce the occurrence of clogging of the porous material on the outer peripheral surface when the die is removed from the molding hole of the chip piece, and it is also possible to significantly reduce the occurrence of clogging during the die removal. In a state where the chip can be compacted, the pressing force at the time of compacting the chip piece can be made larger than in the conventional case, and the abrasion of the inner surface in the molding hole of the mold can be greatly reduced. is there.

Further, the inclination angle of the tapered body on the outer peripheral surface is such that the diameter of the combined body of the chip piece and the cathode-side electrode film formed on the outer periphery is larger at the other end than at the one end. By setting so that it does not become large, when forming a cathode side electrode film of a metal oxide solid electrolyte layer or the like on the chip piece, the thickness of the cathode side electrode film is one end face of the chip piece From the one end face to the other end face, as in the conventional case, the shape of the combined body after the cathode electrode film is formed on the chip piece, even if the thickness gradually increases toward the other end face. The swelling shape can be reliably avoided.

For this reason, when the capacitor element portion is packaged by the mold portion, when the axis of the chip is inclined in the vertical and horizontal directions due to a mounting error, the chip is formed on the outer peripheral surface of the chip. The narrowing of the gap between the cathode electrode film and the upper and lower surfaces and the left and right both surfaces in the mold portion is caused by the fact that the chip piece and the cathode electrode film and the combination formed on the chip piece move from one end to the other end. As a result, the diameter dimension at one end of the chip piece and the cathode-side electrode film and the combination formed thereon can be made larger than in the conventional case. Since the volume of the chip piece can be increased by the amount, there is no clogging in the compacting of the chip piece. The large capacity is to effectively be accomplished without causing the size.

In addition to the above, the present invention further provides a chamfered surface at a corner between the outer peripheral surface and the other end surface of the chip piece, and a portion corresponding to the chamfered surface of the cathode-side electrode film formed on the chip piece. By adopting a configuration in which an insulating resin is applied, when a safety fuse wire for overcurrent or the like is connected to the cathode-side electrode film of the chip piece, the middle of the safety fuse wire is brought into close contact with the insulating resin. As a result, it is possible to secure a predetermined fusing characteristic to the safety fuse wire and to reduce the size and weight of the solid electrolytic capacitor.

Further, as described in claim 2, a parallel surface parallel to the axis of the chip piece is provided on a relatively short portion of the outer peripheral surface of the chip piece adjacent to one end face. Accordingly, since the corner portion in this portion can be prevented from becoming an acute angle smaller than a right angle by forming the chip piece into a tapered body, occurrence of chipping in the corner portion can be reliably reduced.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.
The drawings will be described.

In this figure, reference numeral 11 denotes a molding hole 12.
Reference numeral 13 denotes a vertically movable lower (first) molding die, and reference numeral 14 denotes a vertically movable upper (second) molding die.

A molding hole 12 formed in the molding die 11
The inner diameter of the opening 12a with respect to the upper surface of the molding die 11 is increased as d and the inner diameter of the opening 12b with respect to the lower surface of the molding die 11 is decreased as d1. Then, it is formed in the tapered hole 12c gradually reduced from d to d1.

As shown in FIG. 2, the lower (first) mold 13 is inserted into the lower opening 12b in the molding hole 12, while the metal powder is inserted into the molding hole 12. Fill 15 with.

Next, as shown in FIG. 3, the upper (second) molding die 14 formed by sandwiching the anode rod 16 from both right and left sides is pushed into the upper opening 12a of the molding hole 12, as shown in FIG. By pressing the lower (first) molding die 13, the metal powder 15 is transferred to the molding hole 1.
In the tapered hole 12c in FIG.
Then, the tip piece 17 is solidified and formed so that a part of the anode rod 16 is embedded in one end face 17a.

Then, as shown in FIG. 4, the upper (second) molding die 14 is pulled out from the molding hole 12, while the lower (first) molding die 13 is further pushed into the molding hole 12. By further pressing the lower (first) molding die 13, the compacted chip 17 is extruded from the molding hole 12 and the die is removed, as shown in FIG. Thus, the capacitor element 18 can be obtained.

When the chip 17 is compacted in the molding hole 12, the molding hole 12 is formed in the tapered hole 12c as described above. In the meantime, the diameter dimension of the chip piece 17 (however, the diameter dimension here is the length of one side or the other side when the cross section is square as shown in the figure, and when the cross section is circular, Its diameter
When the cross section is elliptical, the diameter in the major axis direction or the minor axis direction is the same, and the same applies hereinafter). It can be compacted as a tapered body toward the end face 17b.

At the time of compacting the chip piece 17, the pushing movement of the lower (first) mold 13 during the compacting is stopped at a portion slightly before the lower end of the tapered hole 12c, so that the chip piece can be compacted. a relatively short portion of the length L1 which is adjacent to the other end face 17b of the outer circumferential surface 17c in 17, configured to provide a parallel surface 17c ₁ that is parallel to the axis 17d of the chip piece 17. Accordingly, when the chip piece 17 is compacted as a tapered body, the lower (first) molding die 13 is formed into the tapered hole 12c.
By entering the inside, it is possible to reliably prevent the burr from being generated on the other end face 17 b of the chip piece 17.

Further, when the chip piece 17 is compacted, the pushing movement of the upper (second) mold 14 during the compacting is stopped at a position slightly before the upper end of the tapered hole 12c, whereby the chip piece 17 is compacted. a relatively short portion of the length L2 which is adjacent to one end face 17a of the outer circumferential surface 17c in 17, configured to provide a parallel surface 17c ₂ that is parallel to the axis 17d of the chip piece 17.

Thus, when the chip piece 17 is compacted, the upper (second) molding die 14 enters the tapered hole 12c of the molding hole 12 and
In addition to reliably avoiding damage to the inner surface of c, the corners in this portion can be prevented from becoming an acute angle smaller than a right angle by forming the tip piece into a tapered body. The occurrence of chipping can be reliably reduced.

As described above, the chip piece 17 of the capacitor element 18 is connected to the tapered hole 12 c of the molding hole 12.
In the chip piece 17, the tip piece 17 is compacted as a tapered body from one end face 17 a to the other end face 17 b of the tip piece 17.
When the mold is removed from the inside of the molding hole 12 by further pushing the lower (first) molding die 13, the tapered tip piece 17 has an outer peripheral surface 17 c on the inner surface of the tapered molding hole 12 c. Since it is immediately separated from the inner surface of the molding hole 12c without being rubbed by the unevenness of the existing surface roughness, it is possible to greatly reduce the occurrence of clogging of the porous material on the outer peripheral surface 17c. In addition, under the condition that the occurrence of clogging can be greatly reduced at the time of die-cutting, the pressing force at the time of compacting and forming the chip piece 17 can be increased.

On the other hand, the chip piece 17 thus compacted and formed is sintered, and then a dielectric film such as tantalum pentoxide is formed in the same manner as in the conventional case. By forming a graphite film and a metal film after forming a solid electrolyte layer of a metal oxide such as manganese dioxide by the same method, one end face 17a of the surface of the chip piece 17 is removed as shown in FIG. The cathode-side electrode film 19 is formed on the outer peripheral surface 17c and the other end surface 17b.

In forming the cathode side electrode film 19, even if the thickness of the cathode side electrode film 19 gradually increases from the one end face 17a to the other end face 17b of the chip piece 17, The diameter dimension dmax of the combined body of the piece 2 and the cathode-side electrode film 19 formed on the other end face 17b is smaller than the diameter dimension d of the combined body of the chip piece 17 and the cathode-side electrode film 19 at the one end face 17a. This tendency can be avoided by forming the chip piece 17 in advance into a tapered body tapering from the one end face 17a to the other end face 17b of the chip piece 17 as described above.

Therefore, the inclination angle θ of the outer peripheral surface of the tapered body of the chip piece 17 is set to be substantially the same as the inclination angle when the thickness of the cathode-side electrode film 19 is increased toward the lower end. Then, the chip piece 1
By setting the diameter of the combined body of the cathode electrode 7 and the cathode-side electrode film 19 so as not to be larger at the other end face 17b than at the one end face 17a, the cathode electrode film with respect to the chip piece 17 is set. This makes it possible to reliably prevent the shape of the joined body after the formation of 19 from becoming bulged from one end to the other end as in the conventional case.

In this case, the inclination angle θ of the outer peripheral surface of the tapered body of the chip piece 17 is determined by
By setting the diameter of the combined body of the electrode piece 7 and the cathode-side electrode film 19 formed on the outer peripheral surface thereof to be substantially the same at the part of the other end face 17b and the part of the one end face 17a, The reduction in volume due to the tapered body of 17 can be minimized.

Therefore, when this capacitor element 18 is used to manufacture a solid electrolytic capacitor 100 having the form shown in FIGS. 13 and 14 or a solid electrolytic capacitor 200 having a safety fuse having the form shown in FIG. When the capacitor element 18 is fixed to one lead terminal 4 by welding or the like, as shown in FIGS. 7 and 8, the bonding between the chip piece 17 and the cathode-side electrode film 19 in the capacitor element 18 is performed. When the axis 17d of the body is inclined vertically by α1 or α2 due to an attachment error due to bending or the like in the anode rod 16, or inclined by β1 or β2 in the left-right direction, the axis 17d is formed on the outer peripheral surface of the chip piece 17. The distances W1 and W2 between the cathode-side electrode film 19 and the upper and lower surfaces 7a and 7b and the left and right surfaces 7c and 7d in the mold section 7 are different. The Kunar, the chip components 1
Since the combined body of the cathode 7 and the cathode-side electrode film 19 formed thereon does not have a shape that swells from one end to the other end, it can be avoided reliably.

As a result, the diameter of the combined body of the chip piece 17 and the cathode-side electrode film 19 can be made larger than in the conventional case, so that the volume of the chip piece 17 can be increased accordingly.

In addition to this, the present invention is as shown in FIGS.

That is, when the lower (first) molding die 13 'and the upper (second) molding die 14 are pushed into the molding hole 12' formed in the molding die 11 ', the molding hole 1' is pressed.
In addition to the formation of the first tapered hole 12c 'in the lower portion of the first tapered hole 12c' in the same manner as in FIGS. A large second tapered hole 12c "is provided. Other configurations are the same as those described above.

With this configuration, as shown in FIG.
The chip piece 17 'with the anode bar 16' in the capacitor element 18 'is solidified and formed as a tapered body having a chamfered surface 17e' provided at the other end of the chip piece 17 'by the second tapered hole 12c ". be able to.

As a result, as shown in FIG. 11, a cathode-side electrode film 19 'is formed on the outer peripheral surface 17c' and the other end surface 17b 'of the entire surface of the chip piece 17' except for one end surface 17a '. After that, when the insulating resin 20 is applied to the other end, the fact that the outer peripheral surface of the insulating resin 20 protrudes from the outer peripheral surface of the cathode-side electrode film 19 ′ is determined by the presence of the chamfered surface 17 e ′. Can be prevented or reduced.

Therefore, when this capacitor element 18 'is used to construct a solid electrolytic capacitor 200' with a safety fuse as shown in FIG. 12, the cathode electrode film on the chip piece 17 'of the capacitor element 18' is formed. 1
9 'and the cathode lead terminal 5 out of the two lead terminals 4 and 5
Are electrically connected to each other by a safety fuse wire 8 ′ for overcurrent or the like, the middle of the safety fuse wire 8 ′ can be in close contact with the outer peripheral surface of the insulating resin 20. Reference numeral 21 denotes an elastic resin such as a silicone resin applied to the safety fuse wire 8 '.

By the way, in the solid electrolytic capacitor 200 with a safety fuse shown in FIG. 15, the diameter of the safety fuse wire 8 is reduced in order to secure the certainty of the fusing in the safety fuse wire 8. In addition, it is necessary to make the length relatively long. Therefore,
Conventional solid electrolytic capacitor with safety fuse 20
0, one end of the safety fuse wire 8 is joined to a part of the cathode-side electrode film 6 formed on the outer peripheral surface 2c of the chip piece 2 distant from the other end, as shown in FIG. I have to.

However, according to this configuration, when the safety fuse wire 8 is stretched, the safety fuse wire 8 is coated with the elastic resin 8a, and the whole of the safety fuse wire 8 is packaged in the mold portion 7. In some cases, the safety fuse line 8 is sagged and deformed, and a part of the safety fuse line 8 comes into contact with the cathode-side electrode film 6, and the effective length of the safety fuse line 8 is shortened. Thus, it is impossible to obtain a predetermined fusing characteristic.

In this case, in order to increase the effective length of the safety fuse line 8, it is necessary to increase the distance S between the safety fuse line 8 and the cathode-side electrode film 6 in advance.
Since the height R from the cathode-side electrode film 6 to the upper surface of the mold portion 7 on the outer peripheral surface 2c of the chip piece 2 must be increased, the overall height H is increased, and the size of the solid electrolytic capacitor 200 is increased. In addition, in order to lengthen the effective length of the safety fuse wire 8, the cathode side lead terminal 5 is separated from the capacitor element 18, which also increases the size of the solid electrolytic capacitor 200. Invite.

On the other hand, in the case of the present invention, FIG.
As shown in the figure, the middle of the safety fuse line 8 'can be brought into close contact with the insulating resin 20 formed on the cathode-side electrode film 19' in the chip piece 17 '.

As a result, under the condition that the effective length of the safety fuse line 8 'is increased, the safety fuse line 8'
Can be reduced from the cathode-side electrode film 19 ', and the cathode-side lead terminal 5 can be made closer to the capacitor element 18'. The predetermined fusing characteristics can be reliably ensured on the line 8 '.

In each of the above embodiments, the case where the chip piece in the capacitor element is formed in a square cross section is shown. However, the present invention is not limited to this, and the chip piece may be formed in a round or elliptical cross section. Needless to say, the present invention can be applied to such a case.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a compaction apparatus according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional front view showing a first operation state in the first embodiment.

FIG. 3 is a vertical sectional front view showing a second operation state in the first embodiment.

FIG. 4 is a longitudinal sectional front view showing a third operation state in the first embodiment.

FIG. 5 is a perspective view of a capacitor element compacted according to the first embodiment.

FIG. 6 is a vertical sectional front view when a cathode-side electrode film is formed on a chip piece in the capacitor element shown in FIG. 5;

FIG. 7 is a diagram when the capacitor element shown in FIG. 6 is fixed to one lead terminal.

FIG. 8 is a plan view taken along the line VIII-VIII of FIG. 7;

FIG. 9 is a vertical sectional front view of a compacting apparatus according to a second embodiment of the present invention.

FIG. 10 is a vertical sectional front view of a capacitor element according to a second embodiment of the present invention.

FIG. 11 is a longitudinal sectional front view when a cathode-side electrode film is formed on a chip piece of the capacitor element shown in FIG. 10;

12 is a vertical sectional front view of a solid electrolytic capacitor with a safety fuse using the capacitor element shown in FIG. 11;

FIG. 13 is a vertical sectional front view of a conventional solid electrolytic capacitor.

14 is a sectional view taken along the line XVIII-XVIII in FIG.

FIG. 15 is a vertical sectional front view of a conventional solid electrolytic capacitor with a safety fuse.

FIG. 16 is a perspective view showing a conventional capacitor element.

FIG. 17 is a cross-sectional view showing a state where a process of forming a dielectric film of tantalum pentoxide on the chip piece of the capacitor element shown in FIG. 16 is being performed;

18 is a cross-sectional view showing a state in which a process of forming a manganese dioxide solid electrolyte layer on the chip piece of the capacitor element shown in FIG. 16 is performed.

FIG. 19 is a vertical sectional front view when a cathode-side electrode film is formed on a chip piece of the conventional capacitor element.

FIG. 20 is a diagram when the conventional capacitor element is fixed to one lead terminal.

FIG. 21 is a plan view taken along the line XXV-XXV of FIG. 20;

FIG. 22 is a vertical sectional front view showing a first operation state in a conventional compacting apparatus.

FIG. 23 is a vertical sectional front view showing a second operation state in the conventional compacting apparatus.

FIG. 24 is a longitudinal sectional front view showing a third operation state in the conventional compacting apparatus.

[Explanation of symbols]

 18, 18 'capacitor element 17, 17' chip piece 16, 16 'anode bar 17a one end face of chip piece 17b other end face of chip piece 17e' chamfered face of chip piece 17c outer peripheral face of chip piece 17d axis of chip piece 19, 19 'Cathode side electrode film 20 Insulating resin 11, 11' Molding die 12, 12 'Molding hole 12c, 12c', 12c "Tapered hole 13 Lower (first) molding die 14 Metal powder 15 Upper (second) molding die

Claims (2)

[Claims] 1. A chip piece obtained by sintering a metal powder, an anode rod protruding from one end face of the chip piece, and a cathode-side electrode film formed on a part of the outer peripheral face of the chip piece excluding the one end face. In the capacitor element for a solid electrolytic capacitor, the chip piece is formed in a tapered body tapering from one end face to the other end face of the chip piece, and the inclination angle of the outer peripheral surface of the tapered body is The diameter dimension of the combined body of the chip piece and the cathode-side electrode film formed on the outer periphery is set so as not to be larger at the other end face part than at the one end face part. While providing a chamfered surface at the corner with the end face,
A structure of a capacitor element in a solid electrolytic capacitor, wherein an insulating resin is applied to a portion of the cathode-side electrode film corresponding to the chamfered surface. 2. A method according to claim 1, wherein a parallel surface parallel to the axis of the chip piece is provided at a relatively short portion of the outer peripheral surface of the chip piece adjacent to one end face. Characteristic capacitor element structure in solid electrolytic capacitors.