JP2002043175A - Chip type solid-state electrolytic capacitor and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact chip-shaped solid-state electrolytic capacitor of large capacitance which is superior in mounting property on a board, and its manufacturing method. SOLUTION: Parts of an anode lead frame 6 and a cathode lead frame 8 are cut into a tongue-shape, and raise-up parts 7, 9 are formed by bending work. An anode lead wire 2 led from a surface of a capacitor element 1 is made to abut against the tip of the raise-up part 7 so as to intersect the part 7, and the other end of the part 7 is made an external connection terminal. The other raising-up part 9 is set as a guide for positioning the capacitor element 1, and the other end of the part 9 is connected with a part of the capacitor element 1 and made an external connection terminal, which is covered with housing resin 10. The parts of the external connection terminals of the anode and the cathode are exposed so as to become almost flush with the bottom surface of the housing resin 10, respectively, and parts of the raise-up parts 7, 9 of the anode and the cathode are exposed from the side surfaces of the housing resin 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount chip type solid electrolytic capacitor used for various electronic devices and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, there has been a further demand for smaller and larger-capacity chip-type solid electrolytic capacitors due to the development of light and thin electronic components and surface mount technology.

FIG. 8 is a cross-sectional view showing the structure of a conventional chip-type solid electrolytic capacitor. In FIG. 8, reference numeral 21 denotes a capacitor element, and the capacitor element 21 has an anode lead wire 22 exposed at one end. The porous anode body is formed by molding and sintering the powder of the buried valve metal, and an anodic oxide film is formed on a part of the anode lead wire 22 and the entire surface of the porous anode body by a known method. Then, an electrolyte layer and a carbon layer are sequentially formed on the surface, and a cathode layer 23 is further formed on the surface. Note that 24
Is a Teflon (registered trademark) plate attached to the anode lead wire 22, and the Teflon plate 24 is an insulating plate provided on the anode lead wire 22 to prevent the electrolyte from climbing up when an electrolyte layer is formed.

[0004] The capacitor element 21 thus configured
Is the anode lead 2 derived from the capacitor element 21
After cutting, leaving the necessary part of 2, the anode lead-out wire 22 is joined to an anode lead frame 25 made of a strip-shaped single metal plate, and the cathode layer 23 of the capacitor element 21 is connected via a conductive adhesive 27. It is fixed by connecting to the cathode lead frame 26.

[0005] The capacitor element 21 fixed by the anode lead frame 25 and the cathode lead frame 26 is coated with an exterior resin 28 by a transfer molding method.
Are cut into predetermined lengths to form external connection terminals.

The lead-type lead frames 25 and 26 cut to a predetermined length as the external connection terminals are symmetrically bent along the outer surface of the exterior resin 28 to form the external connection terminals, thereby forming a chip-shaped solid. An electrolytic capacitor was constituted.

[0007]

However, in the above-described conventional chip-type solid electrolytic capacitor, the space size of the connection portion between the anode lead-out line 22 derived from the capacitor element 21 and the anode lead frame 25 and the capacitor element 2
The space size of the bending including the connection lead-out portion between the first cathode layer 23 and the cathode lead frame 26 is large, and further, after the capacitor element 21 is covered with the exterior resin 28,
The anode lead frame 25 and the cathode lead frame 26 are cut into a predetermined length as external connection terminals, and are symmetrically bent along the outer surface of the exterior resin 28 to form anode external connection terminals and cathode external connection terminals. The configuration has a problem that the volume of the capacitor element 21 that can be accommodated within the dimensions of the exterior resin 28 is restricted.

That is, a stepped stepped portion provided for connecting the cathode layer 23 to the end of the cathode lead frame 26 and a cathode bent along the outer surface of the exterior resin 28. The external connection terminal becomes an obstacle, and the volume of the capacitor element 21 cannot be increased.

Further, when the anode lead-out wire 22 is joined to the anode lead frame 25 by resistance welding, the joining portion of the anode lead frame 25 is formed in a thin plate shape, so that the contact area of the joining surface is increased. Since the anode lead frame 25 is placed in parallel on the anode lead frame 25 and pressurized, the joint between the anode lead frame 25 and the anode lead line 22 becomes longer, and the volume of the capacitor element 21 cannot be increased. There were also issues.

The present invention solves such a conventional problem,
It is an object of the present invention to provide a chip-type solid electrolytic capacitor that can be reduced in size and capacity and a method for manufacturing the same.

[0011]

Means for Solving the Problems In order to solve the above-mentioned problems, the invention according to the first aspect of the present invention is to form a powder made of a valve action metal having an anode lead wire embedded so that one end is exposed. The capacitor element is formed by sequentially forming a dielectric oxide film, an electrolyte layer, and a cathode layer on an anode body sintered by sintering, and a rising part formed by cutting a part of the element into a tongue shape and bending it. An anode lead frame which abuts the leading end so as to intersect the anode lead-out line exposed from the capacitor element and has the other end serving as an external connection terminal, and a part cut out in a tongue shape and formed by bending. A cathode lead frame having a raised portion serving as a guide for positioning the capacitor element and connected to a part of the cathode layer of the capacitor element and the other end serving as an external connection terminal; and an insulating exterior resin covering the capacitor element. Consisting of Each of the external connection terminals of the anode lead frame and the cathode lead frame is exposed so as to be substantially flush with the bottom surface of the exterior resin, and a part of the rising portion of the anode lead frame and the cathode lead frame is partially exposed. The configuration is such that it is exposed from the side surface of the exterior resin.

With this configuration, the external connection terminals of the anode lead frame and the cathode lead frame do not need to be bent intricately, so that the volume of the capacitor element covered with the exterior resin can be increased. Capacitance can be increased, and a part of the rising portion of the anode lead frame and the cathode lead frame exposed on the outer surface of the exterior resin forms a fillet portion at the time of mounting, so that a chip type is formed. This has the effect that the stability of the mounting posture of the solid electrolytic capacitor can be improved.

According to a second aspect of the present invention, in the first aspect, a step-shaped bent portion is provided at an external connection terminal of the cathode lead frame so as to be separated from a surface of a connection portion of a cathode layer of a capacitor element. With this configuration, the external connection terminals of the cathode lead frame can be easily reduced in size, and the effect of increasing the bonding force with the exterior resin can be obtained.

According to a third aspect of the present invention, in the second aspect of the present invention, the cathode lead frame is provided with cutouts provided at both ends of the bent portion of the external connection terminal of the external connection terminal. With such a configuration, there is an operational effect that the bonding force between the external connection terminal of the cathode lead frame and the exterior resin can be further increased.

According to a fourth aspect of the present invention, there is provided an anode body formed by molding and sintering a powder of a valve action metal in which an anode lead wire is embedded so that one end is exposed, a dielectric oxide film, an electrolyte layer,
The cathode layer is sequentially formed to form a capacitor element, and then
A part of the anode lead frame and the cathode lead frame are cut out in a tongue-like shape, and these are bent so as to be raised in the opposite direction to provide rising portions, and the rising portions of the cathode lead frame are used to position the capacitor element. As a guide to connect a part of the cathode layer of the capacitor element to the external connection terminal at the other end via a conductive adhesive,
After connecting the anode lead wire exposed from the capacitor element to the tip of the rising portion of the anode side lead frame so as to cross, a part of the rising portion of the anode lead frame and the cathode lead frame and an external connection terminal Of the capacitor element is covered with an insulative exterior resin using a molding die so that a part of the capacitor element is continuously exposed.This method increases the volume of the capacitor element. Therefore, the solid electrolytic capacitor having a high capacitance can be stably produced.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the outer surfaces of the anode lead frame and the cathode lead frame are exposed so as to be substantially flush with the outer surface of the exterior resin covering the capacitor element. A method of forming a molding die using the exposed surface of the connection terminal as a parting line, and covering the capacitor element with an insulating exterior resin using the molding die. In addition, a part of the external connection terminal of the cathode lead frame can be accurately exposed so as to be substantially flush with the outer surface of the exterior resin, and a part of the rising portion of the lead frame is simultaneously exposed. Therefore, there is an operational effect that highly reliable mounting can be performed when surface mounting is performed on a printed circuit board or the like.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a perspective view showing a chip type solid electrolytic capacitor according to Embodiment 1 of the present invention. In FIG. An anode lead frame 8 is exposed to the outside, and a cathode lead frame 8 is exposed to the bottom of the exterior resin 10. One end of each of the anode lead frame 6 and the cathode lead frame 8 is configured as an external connection terminal. Reference numeral 7 denotes a rising portion formed of the anode lead frame 6 exposing a part of the side surface of the exterior resin 10. Also,
The rising portion (not shown) made of the cathode lead frame 8 is similarly exposed on the surface facing the rising portion 7 made of the anode lead frame 6.

Further, the chip type solid electrolytic capacitor according to the first embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is a cross-sectional view showing the internal structure of FIG. 1. Reference numeral 1 denotes a capacitor element. This capacitor element 1 is formed by molding a tantalum powder made of a valve action metal in which an anode lead wire 2 is embedded so that one end is exposed. A dielectric oxide film, an electrolyte layer, and a carbon layer are sequentially formed on the surface of a porous tantalum anode body by a known method, and then a cathode layer 4 made of silver paint is formed on the surface of the carbon layer. I have. Reference numeral 3 denotes an insulating plate for preventing the electrolyte from climbing up to the anode lead wire 2 when the electrolyte layer is formed.

Reference numeral 6 denotes an anode lead frame, and reference numeral 7 denotes a rising portion formed by cutting out a part of the anode lead frame 6 in a tongue shape and bending the anode lead frame 6 upward. Reference numeral 8 denotes a cathode lead frame, and reference numeral 9 denotes a rising portion formed by cutting out a part of the cathode lead frame 8 in a tongue shape and bending it so as to raise it upward. Reference numeral 10 denotes an exterior resin, which exposes a part of the external connection terminals of the anode lead frame 6 and the cathode lead frame 8 so as to be substantially flush with the bottom surface of the exterior resin 10, respectively. The capacitor element 1 is covered so that a part of the rising portions 7 and 9 of the frame 8 is exposed from the side surface of the exterior resin 10.

The anode lead frame 6 and the cathode lead frame 8 are formed of a strip-shaped lead frame as shown in FIG. 3. In FIG. 3, reference numeral 11 denotes a strip-shaped metal plate having a central portion. Is cut off to separate the anode lead frame 6 and the cathode lead frame 8, and a tongue-shaped notch is provided in a part of each of the cut portions, and the rising portion 7 is bent so that the anode lead frame 6 is raised upward. Provided,
The cathode lead frame 8 also has a rising portion 9 which is bent so as to raise a tongue-shaped notch upward.

To fix the capacitor element 1 to the anode lead frame 6 and the cathode lead frame 8, FIG.
As shown in the figure, the external connection terminal portion of the cathode lead frame 8 and its rising portion 9 are positioned at the rising portion 9 of the cathode lead frame 8 with the thermosetting conductive adhesive 5 interposed therebetween. The anode lead-out line 2 exposed from the capacitor element 1 is welded and fixed to the tip of the rising portion 7 so as to cross.

The exterior resin 10 is coated and formed by a transfer molding method or the like. As shown in FIG. 5, an upper mold 12 having heel portions 12a and 12b is provided.
By arranging the anode lead frame 6 and the cathode lead frame 8 to which the capacitor element 1 is connected on the parting line 14 of the resin molding die composed of the lower die 13 having the Lead frame 6
The outer resin 1 is formed such that a part of the rising part 7 of the metal and a part of the rising part 9 of the cathode lead frame 8 are respectively exposed on the outer surface.
0 is to be coated. A part of the rising part 7 of the anode lead frame 6 and a part of the rising part 9 of the cathode lead frame 8 exposed on the outer surface serve as a fillet forming part when a product is mounted on a substrate. Things.

The anode lead frame 6 and the cathode lead frame 8 to which the capacitor element 1 covered with the exterior resin 10 is connected are connected to a part of the anode lead frame 6 which is exposed from the exterior resin 10 by an anode external connection. A chip-type solid electrolytic capacitor is completed by cutting and separating a portion having a predetermined size as a terminal and a portion of the cathode lead frame 8 exposed from the exterior resin 10 as a cathode external connection terminal.

As described above, the chip-type solid electrolytic capacitor and the method of manufacturing the same according to the first embodiment of the present invention provide a method for connecting the cathode lead frame 8 and its rising portion 9 to the cathode layer 4 of the capacitor element 1. The structure is such that obstacles due to bending of the lead frame 8 are small and the capacitor element 1 can be enlarged. Therefore, even if the external dimensions of the chip-type solid electrolytic capacitor are the same, the volume of the capacitor element 1 can be increased.

The rising portion 7 of the anode lead frame 6
And the anode lead wire 2 are crossed and joined, so that the joining method can be simplified and the capacitor element 1 can be enlarged.

Further, since the portions where the anode and cathode lead frames 6 and 8 are exposed on one side of the exterior resin 10 are cut into predetermined dimensions as external connection terminals, they are formed along the outer surface of the exterior resin 10 as in the prior art. In addition, since it is not necessary to bend the lead frame, the dimensions of the exterior resin 10 can be increased, and the volume of the capacitor element 1 can be increased.

Further, when covering the exterior resin 10, the rising portion 7 of the anode lead frame 6 and the rising portion 9 of the cathode lead frame 8 are respectively indicated by the heel portions 12a and 12b of the upper mold 12 of the exterior resin. It is configured to be put out so as to come out. As a result, when the product is mounted on the board, the raised portions 7 of the anode lead frame 6 and the raised portions 9 of the cathode lead frame 8 function as fillet forming portions.

Therefore, even if the external dimensions of the chip type solid electrolytic capacitor are the same as those of the conventional type, the volume of the capacitor element 1 can be increased, the capacitance is large, and the reliability of the mounting is improved by the action of the fillet forming portion. A highly reliable chip-type solid electrolytic capacitor can be provided.

(Embodiment 2) In Embodiment 1, the external connection terminals of the cathode lead frame 8 are stepped away from the surface of the connection portion of the cathode layer 4 of the capacitor element 1 as shown in FIG. A bent portion 8a is provided,
Thereafter, the chip-shaped solid electrolytic capacitor is produced by coating the exterior resin 10 in the same manner as in the first embodiment, thereby securing the strength of the external connection terminals and simultaneously balancing the shape of the external connection terminals of the anode and the cathode of the product. Can be secured.

(Embodiment 3) The bent portion 8 of the external connection terminal of the cathode lead frame 8 in Embodiment 2
7, a notch 8b is provided inside both ends of the bent portion 8a as shown in FIG. 7, and thereafter the exterior resin 10 is coated in the same manner as in the first embodiment to produce a chip-type solid electrolytic capacitor. Thereby, higher strength of the external connection terminal can be secured.

[0032]

As described above, according to the chip type solid electrolytic capacitor of the present invention and the method of manufacturing the same, a part of the anode lead frame and the cathode lead frame are cut out like a tongue.
This is bent to provide a rising part, and the leading end of this rising part is abutted so as to intersect the anode lead wire exposed from the capacitor element, the other end is used as an external connection terminal, and the other rising part is used. Insulating exterior resin that covers the capacitor element fixed to the anode lead frame and the cathode lead frame as an external connection terminal by connecting the other end to a part of the cathode layer of the capacitor element as a guide for positioning the capacitor element A part of the external connection terminals of the anode lead frame and the cathode lead frame are exposed so as to be substantially flush with the bottom surface of the exterior resin, respectively, and one of the rising portions of the anode lead frame and the cathode lead frame is formed. By exposing the part from the side of the exterior resin, the chip type solid electrolytic capacitor of the same size Even though the volume of the capacitor element can be made larger than in the past, it is possible to provide a chip-type solid electrolytic capacitor with high reliability in mounting, with the effect of the fillet forming portion, as well as the miniaturization and large capacity. It is.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a chip-type solid electrolytic capacitor according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a chip-type solid electrolytic capacitor according to the first embodiment.

FIG. 3 is a plan view of an anode lead frame and a cathode lead frame according to the first embodiment.

FIG. 4 is a sectional view in which a capacitor element is fixed to the anode lead frame and the cathode lead frame according to the first embodiment.

FIG. 5 is a partial sectional view showing an exterior resin molding die according to the first embodiment.

FIG. 6 is a cross-sectional view in which a capacitor element is fixed to an anode lead frame and a cathode lead frame according to the second embodiment of the present invention.

FIG. 7 is a plan view of an anode lead frame and a cathode lead frame according to a third embodiment of the present invention.

FIG. 8 is a sectional view showing a configuration of a conventional chip-type solid electrolytic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Anode lead-out line 3 Insulating plate 4 Cathode layer 5 Conductive adhesive 6 Anode lead frame 7 Anode lead frame rising part 8 Cathode lead frame 9 Cathode lead frame rising part 10 Exterior resin

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01G 9/24 CE (72) Inventor Masakuni Ogino 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Hiroyuki Aso 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture, Japan Inside Matsushita Electric Industrial Co., Ltd. Matsushita Electric Industrial Co., Ltd., 1006, Matsushita Electric Industrial Co., Ltd. Sangyo Co., Ltd.

Claims (5)

[Claims] 1. A dielectric oxide film, an electrolyte layer, and a cathode layer are sequentially formed on an anode body formed by molding and sintering a powder of a valve action metal having an anode lead wire embedded so that one end is exposed. The capacitor element and a part thereof are cut out in a tongue shape and abutted so that the leading end of the rising portion provided by bending the anode element crosses the anode lead-out line exposed from the capacitor element, and the other end is externally connected. An anode lead frame as a connection terminal, a part cut out in a tongue shape, and a rising part provided by bending the part is used as a guide for positioning the capacitor element and a part of a cathode layer of the capacitor element And a cathode lead frame having the other end as an external connection terminal, and an insulating outer resin covering the capacitor element, and a part of the external connection terminal of the anode lead frame and the cathode lead frame. A chip-type solid electrolytic device in which each is exposed so as to be substantially flush with the bottom surface of the exterior resin, and a part of a rising portion of the anode lead frame and the cathode lead frame is exposed from a side surface of the exterior resin. Capacitors. 2. The chip-type solid electrolytic capacitor according to claim 1, wherein a step-like bent portion is provided at an external connection terminal of the cathode lead frame so as to be away from a surface of a connection portion of the capacitor element with the cathode layer. 3. A notch is provided on both sides of both ends of the bent portion of the external connection terminal of the cathode lead frame.
2. The chip-type solid electrolytic capacitor according to item 1. 4. A capacitor in which a dielectric oxide film, an electrolyte layer, and a cathode layer are sequentially formed on an anode body formed by molding and sintering a powder of a valve action metal having an anode lead wire embedded so that one end thereof is exposed. After forming the element, a part of the anode lead frame and the cathode lead frame are cut out in a tongue shape and bent so as to be raised in a counter electrode direction to provide a rising portion, respectively, and a rising portion of the cathode lead frame is provided. A part of the cathode layer of the capacitor element is connected to the external connection terminal at the other end via a conductive adhesive as a guide for positioning the capacitor element, and then a rising portion of the anode side lead frame is connected. After connecting the anode lead wire exposed from the capacitor element to the tip of the capacitor so as to cross, a part of the rising portions of the anode lead frame and the cathode lead frame and one of the external connection terminals are connected. A method for manufacturing a chip-type solid electrolytic capacitor in which a capacitor element is covered with an insulating exterior resin using a molding die so that each part is continuously exposed. 5. A molding die, wherein the exposed surfaces of the external connection terminals of the anode lead frame and the cathode lead frame, which are exposed so as to be substantially flush with the outer surface of the exterior resin covering the capacitor element, are used as parting lines to form a molding die. 5. The method for manufacturing a chip-type solid electrolytic capacitor according to claim 4, wherein said capacitor element is formed and said capacitor element is covered with an insulating exterior resin using said mold.