JP3968971B2 - Chip-type solid electrolytic capacitor and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface-mounted chip-type solid electrolytic capacitor used in various electronic devices and a method for manufacturing the same.
[0002]
[Prior art]
In recent years, chip-type solid electrolytic capacitors are increasingly required to be smaller and larger in capacity due to the progress of light and thin electronic devices and surface mounting technology.
[0003]
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. The capacitor element 21 is a valve in which an anode lead wire 22 is embedded so as to expose one end. A powder made of a working metal is molded and sintered to form a porous anode body, and an anodic oxide film is formed on a part of the anode lead-out line 22 and the entire surface of the porous anode body by a known method, An electrolyte layer and a carbon layer are sequentially formed on the surface, and a cathode layer 23 is further formed on the surface. Reference numeral 24 denotes a Teflon plate attached to the anode lead-out line 22. The Teflon plate 24 is an insulating plate provided on the anode lead-out line 22 to prevent the electrolyte from creeping up when the electrolyte layer is formed.
[0004]
The capacitor element 21 configured in this manner is cut out leaving a necessary portion of the anode lead-out line 22 led out from the capacitor element 21 and then led out to the anode lead frame 25 made of a single strip metal plate. The wire 22 is joined and fixed by connecting the cathode layer 23 of the capacitor element 21 to the cathode lead frame 26 via the conductive adhesive 27.
[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, and then each of the anode lead frame 25 and the cathode lead frame 26 is cut into a predetermined length. Use as an external connection terminal.
[0006]
The lead-type frames 25 and 26 cut to a predetermined length as the external connection terminals are bent symmetrically along the outer surface of the exterior resin 28 to form the external connection terminals. It was composed.
[0007]
[Problems to be solved by the invention]
However, in the above-described conventional chip-type solid electrolytic capacitor, the space dimension of the connection portion between the anode lead wire 22 and the anode lead frame 25 derived from the capacitor element 21 and the connection lead-out between the cathode layer 23 and the cathode lead frame 26 of the capacitor element 21. The space dimension of the bending including the portion is large. Further, after covering the capacitor element 21 with the exterior resin 28, the anode lead frame 25 and the cathode lead frame 26 are cut into a predetermined length dimension using the external connection terminals as the exterior resin. 28, the volume of the capacitor element 21 that can be accommodated within the dimensions of the exterior resin 28 is restricted because the anode external connection terminal and the cathode external connection terminal are formed symmetrically along the outer surface of the external resin 28. Had.
[0008]
That is, a stepped portion, which is provided to connect the cathode layer 23 to the end portion of the cathode lead frame 26, and is bent along the outer surface of the exterior resin 28. Becomes an obstacle, and the volume of the capacitor element 21 cannot be increased.
[0009]
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 flat plate shape. Since the anode lead-out wire 22 is placed in parallel on the frame 25 and pressed, the joint between the anode lead frame 25 and the anode lead-out wire 22 becomes long, and the volume of the capacitor element 21 cannot be increased. Was.
[0010]
An object of the present invention is to solve such a conventional problem and to provide a chip-type solid electrolytic capacitor that can be reduced in size and increased in capacity and a manufacturing method thereof.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention provides a dielectric body on an anode body formed by sintering a powder made of a valve metal having an anode lead wire embedded so that one end is exposed. A capacitor element formed by sequentially forming an oxide film, an electrolyte layer, and a cathode layer, and a portion cut out into a tongue-like shape, and this was exposed from the capacitor element at the tip of a rising portion provided by bending Position the capacitor element with an anode lead frame that contacts the lead-out line of the anode and has the other end as an external connection terminal, and a raised part that is partly cut into a tongue and bent. A cathode lead frame connected to a part of the cathode layer of the capacitor element and having the other end as an external connection terminal, and an insulating exterior resin covering the capacitor element, the anode lead frame and Electrode to expose a portion of each of the external connection terminals of the lead frame such that the bottom surface and substantially the same surface of the exterior resin, and provided on the tongue-like the anode lead frame and / or the cathode lead frame Startup A part of the part is exposed from the side surface of the exterior resin.
[0012]
With this configuration, since it is not necessary to bend the external connection terminals of the anode lead frame and the cathode lead frame in a complicated manner, the volume of the capacitor element covered with the exterior resin can be increased. In addition, the anode lead frame exposed on the outer surface of the exterior resin and a part of the rising part of the cathode lead frame form a fillet portion during mounting, so that a chip-type solid electrolytic capacitor This has the effect of improving the stability of the mounting posture.
[0013]
According to a second aspect of the present invention, in the first aspect of the invention, the external connection terminal of the cathode lead frame is provided with a stepped bent portion so as to be separated from the surface of the connection portion of the cathode layer of the capacitor element. With this configuration, the external connection terminal of the cathode lead frame can be easily accommodated in a small size, and the effect of increasing the bonding force with the exterior resin can be obtained.
[0014]
According to a third aspect of the present invention, in the second aspect of the present invention, a notch is provided on the inner side from both ends of the bent portion of the external connection terminal of the cathode lead frame. As a result, there is an effect that the bonding force between the external connection terminal of the cathode lead frame and the exterior resin can be further increased.
[0015]
In the invention according to claim 4, a dielectric oxide film, an electrolyte layer, and a cathode layer are sequentially formed on an anode body formed by sintering a powder made of a valve metal having an anode lead wire embedded so that one end is exposed. Then, a capacitor element is formed. Next, a part of the anode lead frame and the cathode lead frame is cut out in a tongue-like shape, bent so as to be raised in the counter electrode direction, and each raised portion is provided. A part of the cathode layer of the capacitor element is connected to an external connection terminal at the other end via a conductive adhesive using the rising portion of the frame as a guide for positioning the capacitor element, and then the anode-side lead frame the tip of the rising portion after connecting to intersect the anode lead wire which is exposed to the outside from the capacitor element, in the tongue-like the anode lead frame and / or the cathode lead frame Those vignetting has a portion of the part and the external connection terminal of the rising portion has a manufacturing method of coating the capacitor element with an insulating sheathing resin using molding die so as to expose each sequentially By this method, the volume of the capacitor element can be increased, and a solid electrolytic capacitor having a high capacitance can be produced stably.
[0016]
According to a fifth aspect of the present invention, in the invention of the fourth aspect, the anode lead frame and the external connection terminal of the cathode lead frame that are exposed so as to be substantially flush with the outer surface of the exterior resin covering the capacitor element. A mold is formed by using the exposed surface as a parting line, and the capacitor element is covered with an insulating exterior resin using the mold, and an anode lead frame and a cathode lead A part of the external connection terminal of the frame can be accurately exposed so that it is substantially flush with the outer surface of the exterior resin, and a part of the rising portion of the lead frame can be exposed simultaneously. Therefore, there is an effect that a highly reliable mounting can be performed when surface mounting on a printed circuit board or the like.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0018]
(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. 1, 10 is an exterior resin, 6 is an anode lead frame exposed on the bottom surface of the exterior resin 10, and 8 Is a cathode lead frame exposed on the bottom surface of the exterior resin 10, and one ends of the anode lead frame 6 and the cathode lead frame 8 are respectively configured as external connection terminals. Reference numeral 7 denotes a rising portion made of an anode lead frame 6 in which a part of the side surface portion of the exterior resin 10 is exposed. Further, a rising portion (not shown) made of the cathode lead frame 8 is exposed in the same manner on the surface facing the rising portion 7 made of the anode lead frame 6.
[0019]
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 configuration of FIG. 1, wherein 1 is a capacitor element, and this capacitor element 1 is formed of tantalum powder made of a valve metal having an anode lead wire 2 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 the 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. Yes. Reference numeral 3 denotes an insulating plate for preventing the electrolyte from creeping up to the anode lead-out line 2 when the electrolyte layer is formed.
[0020]
Reference numeral 6 denotes an anode lead frame, and reference numeral 7 denotes a rising portion obtained by bending a part of the anode lead frame 6 into a tongue shape and bending it upward. Reference numeral 8 denotes a cathode lead frame, and reference numeral 9 denotes a rising portion obtained by bending a part of the cathode lead frame 8 into a tongue piece and bending it upward. Reference numeral 10 denotes an exterior resin, which exposes 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, and the anode lead frame 6 and the cathode lead. The capacitor element 1 is covered so that part of the rising portions 7 and 9 of the frame 8 is exposed from the side surface of the exterior resin 10.
[0021]
Further, the anode lead frame 6 and the cathode lead frame 8 are each composed of a strip-shaped lead frame as shown in FIG. 3. In FIG. The anode lead frame 6 and the cathode lead frame 8 are separated from each other. A tongue-shaped cutout is provided in each part, and a rising portion 7 is provided that is bent so that the anode lead frame 6 is raised upward. The lead frame 8 side is also provided with a rising portion 9 that is bent so as to raise a tongue-shaped notch upward.
[0022]
In order to fix the capacitor element 1 to the anode lead frame 6 and the cathode lead frame 8, as shown in FIG. 4, a thermosetting conductive adhesive is applied to the external connection terminal portion of the cathode lead frame 8 and its rising portion 9. 5 is positioned by the rising portion 9 of the cathode lead frame 8 and fixed to the tip of the rising portion 7 of the anode lead frame 6 by welding so that the anode lead-out line 2 exposed from the capacitor element 1 intersects. To do.
[0023]
The exterior resin 10 is formed by coating by a transfer molding method or the like, and as shown in FIG. 5, a resin comprising an upper mold 12 provided with heel portions 12a and 12b and a lower mold 13 provided with a cavity portion. The anode lead frame 6 and the cathode lead frame 8 to which the capacitor element 1 is connected are placed on the parting line 14 of the molding die and molding is performed, whereby a part of the rising portion 7 of the anode lead frame 6 and the cathode are formed. The exterior resin 10 is coated so that a part of the rising portion 9 of the lead frame 8 is exposed on the outer surface. 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 become a fillet forming part when the product is mounted on the substrate. Is.
[0024]
Further, the anode lead frame 6 and the cathode lead frame 8 to which the capacitor element 1 coated with the exterior resin 10 is connected have a portion where the anode lead frame 6 is exposed from the exterior resin 10 as an anode external connection terminal, A portion of the cathode lead frame 8 exposed from the exterior resin 10 is cut into a predetermined size and separated as a cathode external connection terminal, thereby completing a chip-type solid electrolytic capacitor.
[0025]
As described above, the chip-type solid electrolytic capacitor and the method for manufacturing the same according to the first embodiment of the present invention connect the cathode lead frame 8 and its rising portion 9 and the cathode layer 4 of the capacitor element 1 to the cathode lead frame 8. Therefore, the capacitor element 1 can be enlarged with less obstruction due to bending. Therefore, the volume of the capacitor element 1 can be increased even when the external dimensions of the chip-type solid electrolytic capacitor are the same.
[0026]
Further, since the rising portion 7 of the anode lead frame 6 and the anode lead-out line 2 are joined in a cross shape, the joining method can be simplified and the capacitor element 1 can be enlarged.
[0027]
In addition, in order to cut the anode and cathode lead frames 6, 8 on one side of the exterior resin 10 to a predetermined dimension using external connection terminals, the lead is provided along the outer surface of the exterior resin 10 as in the prior art. Since it is not necessary to bend the frame, the dimension of the exterior resin 10 can be increased, and the volume of the capacitor element 1 can be increased.
[0028]
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 exposed by the heel portions 12a and 12b of the upper mold 12 of the exterior resin, respectively. It is configured to be exteriorized. As a result, when the product is mounted on the substrate, the raised portion 7 of the anode lead frame 6 and the raised portion 9 of the cathode lead frame 8 that are exposed act as fillet forming portions.
[0029]
Therefore, even if the external dimensions of the chip-type solid electrolytic capacitor are the same as the conventional one, the volume of the capacitor element 1 can be increased, the capacitance is large, and the mounting reliability is high due to the action of the fillet forming portion. A chip-type solid electrolytic capacitor can be provided.
[0030]
(Embodiment 2)
In the first embodiment, the external connection terminal of the cathode lead frame 8 is provided with a bent portion 8a bent stepwise so as to be away from the connection portion surface of the cathode layer 4 of the capacitor element 1, as shown in FIG. In the same manner as in the first embodiment, a chip-type solid electrolytic capacitor is manufactured by coating the exterior resin 10, thereby ensuring the strength of the external connection terminals and at the same time ensuring the shape balance of the external connection terminals of the product anode and cathode. can do.
[0031]
(Embodiment 3)
In the second embodiment, the bent portion 8a of the external connection terminal of the cathode lead frame 8 is provided with notches 8b inside both ends of the bent portion 8a as shown in FIG. 7, and thereafter the same as in the first embodiment. Thus, by coating the exterior resin 10 to produce a chip-type solid electrolytic capacitor, higher strength of the external connection terminal can be ensured.
[0032]
【The invention's effect】
As described above, the chip-type solid electrolytic capacitor and the method for manufacturing the same of the present invention cut out part of the anode lead frame and the cathode lead frame into a tongue-like shape, and bent them to provide a rising portion. The other end is used as an external connection terminal, the other riser is used as a guide for positioning the capacitor element, and the other end is used as a guide for positioning the capacitor element. It consists of an insulating exterior resin that covers the anode lead frame and the capacitor element fixed to the cathode lead frame as an external connection terminal connected to a part of the cathode layer, and external connection of the anode lead frame and the cathode lead frame. some of the terminals respectively to expose such that the bottom surface and substantially the same surface of the exterior resin, and the anode lead frame and / or By a portion of a rising portion provided pole on the tongue-shaped lead frame configuration which is adapted exposed from the side surfaces of the exterior resin, a size of a chip type solid electrolytic capacitor of the same size However, the volume of the capacitor element can be made larger than before, and the chip type solid electrolytic capacitor with high mounting reliability can be provided by the action of the fillet forming portion as well as the reduction in size and capacity. .
[Brief description of the drawings]
FIG. 1 is a perspective view showing a chip-type solid electrolytic capacitor according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view showing a configuration of the chip-type solid electrolytic capacitor according to Embodiment 1. FIG. 4 is a plan view of an anode lead frame and a cathode lead frame in FIG. 1. FIG. 4 is a cross-sectional view in which capacitor elements are fixed to the anode lead frame and the cathode lead frame in Embodiment 1. FIG. FIG. 6 is a partial cross-sectional view showing a mold. 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 a second embodiment of the present invention. And FIG. 8 is a cross-sectional view showing the structure of a conventional chip-type solid electrolytic capacitor.
DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Anode lead-out line 3 Insulation board 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

Claims (5)

A capacitor element formed by sequentially forming a dielectric oxide film, an electrolyte layer, and a cathode layer on an anode body formed by molding and sintering a powder made of a valve action metal having an anode lead wire embedded so that one end is exposed; An anode with the other end connected to the tip of a rising portion provided by bending a part of the tongue and bending the lead so that the anode lead-out line exposed from the capacitor element intersects the external connection terminal A lead frame and a raised portion provided by bending a part of the lead frame and bending it serve as a guide for positioning the capacitor element, and are connected to a part of the cathode layer of the capacitor element and connected to the other end. A cathode lead frame having an external connection terminal and an insulating exterior resin for covering the capacitor element, and each of the anode lead frame and a part of the external connection terminal of the cathode lead frame is externally coated. To expose such that the bottom surface and substantially the same plane, and a portion of the rising portion provided on the tongue-like the anode lead frame and / or the cathode lead frame so as to be exposed from the side surfaces of the exterior resin Chip type solid electrolytic capacitor.   2. The chip-type solid electrolytic capacitor according to claim 1, wherein a stepped bent portion is provided at an external connection terminal of the cathode lead frame so as to be separated from a surface of the connection portion with the cathode layer of the capacitor element.   3. The chip-type solid electrolytic capacitor according to claim 2, wherein notches are provided on the inner side from both ends of the bent portion of the external connection terminal of the cathode lead frame. A capacitor element is formed by sequentially forming a dielectric oxide film, an electrolyte layer, and a cathode layer on an anode body formed by sintering and sintering a powder made of a valve action metal in which an anode lead wire is embedded so that one end is exposed, Next, a part of the anode lead frame and the cathode lead frame is cut out in the shape of a tongue, and is bent so as to be raised in the opposite direction, and each rising part is provided, and the rising part of the cathode lead frame is used as the capacitor element. As a guide for positioning, 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, and then the capacitor is connected to the tip of the rising portion of the anode side lead frame. after connecting to intersect the anode lead wire is exposed to the outside through the device, the anode lead frame and / or a portion of the rising portion provided on the tongue-shaped cathode lead frame Method for manufacturing a chip type solid electrolytic capacitor and a portion of the external connection terminals covers the capacitor element with an insulating sheathing resin using molding die so as to expose each sequentially.   A mold is formed by using the anode lead frame exposed to be substantially flush with the outer surface of the exterior resin covering the capacitor element and the exposed surface of the external connection terminal of the cathode lead frame as a parting line. The method for producing a chip-type solid electrolytic capacitor according to claim 4, wherein the capacitor element is covered with an insulating exterior resin using a molding die.

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