JPH0722289A - Solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To allow miniaturization while increasing the capacity by providing a step or, a recess at least in the bottom of an anode body and connecting a cathode terminal therewith. CONSTITUTION:A rectangular capacitor element 2 comprises an anode body produced by compression molding fine powder of tantalum and sintering, and a cathode layer comprising an anodic oxidation film, a solid electrolyte layer of manganese dioxide, for example, a carbon layer, and a conductive silver paste layer formed on the anode body. The capacitor element 2 is provided, at an end of bottom part 3 thereof, with a step 4 extending from one side face to the opposite side face and an anode lead wire 6 of tantalum, for example, is led out from the upper part 5 thereof. The exterior 7 is formed by transfer molding of an epoxy resin and an anode terminal 8 is resistance welded to the lead wire 8 and then bent toward the bottom face along the peripheral surface of the exterior 7. The cathode terminal 9 is bonded through a conductive bonding paste 10 to the cathode layer with the forward end thereof being disposed at the step 4 and bent toward the bottom face along the peripheral surface of the exterior.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a solid electrolytic capacitor.

[0002]

2. Description of the Related Art Solid electrolytic capacitor 50 made of tantalum or the like
For example, as shown in FIG. 10, while pulling out the anode lead wire 51 made of tantalum wire or the like, fine powder of tantalum or the like is compression-molded into a prismatic or cylindrical shape, sintered, and then anodized film, manganese dioxide. A capacitor element 52 in which a solid electrolyte layer such as the above and a cathode layer including a carbon layer and a conductive silver paste layer are sequentially formed is used. Then, the frame-shaped anode terminal 53 is resistance-welded to the anode lead wire 51, and the frame-shaped cathode terminal 54 is connected to the capacitor element 52.
To the cathode layer on the side surface 55 of the. Further, an outer casing 56 is provided around the capacitor element 52 by molding a resin or the like. The anode terminal 53 and the cathode terminal 54 are bent toward the bottom surface of the exterior 56.

Further, as shown in FIG. 11, there is also a solid electrolytic capacitor 61 having a structure in which a cathode terminal 57 is bent and connected to a cathode layer on a bottom surface 59 of a capacitor element 58 and is drawn out of an exterior 60.

Then, as shown in FIG. 12, the anode terminal 62 is
Is connected to the lead wire 63 for the anode with its tip being perpendicular to the lead wire 63, and the cathode terminal 64 is connected to the capacitor element 65.
There is also a solid electrolytic capacitor 68 which is connected to the side surface 66 of the above, and has a structure in which these are drawn out of the exterior 67.

[0005]

However, FIG. 10 and FIG.
In the solid electrolytic capacitors 50 and 68 having the structure of 2, the outer casings 56 and 67 must be thickened at the portions where the cathode terminals 54 and 64 are connected to the side surfaces 55 and 66 of the capacitor elements 52 and 65, respectively. Therefore, if the external dimensions of the solid electrolytic capacitors 50 and 68 are constant, the volumes of the capacitor elements 52 and 65 must be reduced accordingly, and there is a drawback that the capacitance is reduced. If the capacities of the capacitor elements 52 and 65 are made the same so as to make the capacities the same, the solid electrolytic capacitors 50 and 68 have the disadvantage of becoming large.

Also in the solid electrolytic capacitor 61 shown in FIG. 11, the outer casing 60 must be thickened at the portion where the cathode terminal 57 is connected to the bottom surface of the capacitor element 58. Therefore, the solid electrolytic capacitor 61 also has the drawback that the capacity must be reduced or the size must be increased.

Further, in the conventional example shown in FIGS. 10 to 12, generally, an anode terminal is resistance-welded to an anode lead wire.
Therefore, in the case of FIGS. 10 and 11, the welded portion becomes large, and the lead wire for the anode must be lengthened. Therefore, there are drawbacks such that the capacitor element must be shortened to reduce the capacitance and the solid electrolytic capacitor must be enlarged in size.

The present invention improves the above drawbacks and provides a solid electrolytic capacitor capable of increasing capacity and downsizing.

[0009]

In order to achieve the above object, the invention according to claim 1 provides an anode body made of a valve metal, from which an anode lead wire is drawn out, an anodized film, a solid electrolyte layer, and In a solid electrolytic capacitor provided with a cathode layer and a cathode terminal connected to the cathode layer, an anode body provided with a step portion or a concave portion at least at the bottom, and a cathode terminal connected to the cathode layer of the step portion or the concave portion The present invention provides a solid electrolytic capacitor characterized by having.

The invention of claim 2 is the solid electrolytic capacitor of claim 1, wherein the lead wire for the anode is obliquely penetrated, and the solid electrolytic capacitor has an anode terminal welded to the lead wire for the anode by laser light. It is provided.

[0011]

[Function] Since a step or a recess is provided on the bottom of the anode body, and the cathode terminal is arranged and connected to this step, the cathode terminal is completely prevented from protruding from the side surface or bottom surface of the capacitor element. You can do or reduce it. Therefore, as the solid electrolytic capacitor, the volume of the capacitor element can be increased without changing the external dimensions, and the capacitance can be increased. When the size of the capacitor element is not changed, the external packaging can be made thin, so that the solid electrolytic capacitor can be made compact.

Also, since the anode terminal is welded to the anode lead wire by laser light, the welded portion can be made narrower,
The lead wire for the anode can be shortened. Therefore, the capacity of the capacitor element can be increased to increase the capacity, and the solid electrolytic capacitor can be downsized. At this time, since the anode terminal is slanted and welded by laser light, the portion of the anode lead wire melted by laser light is closer to the tilted side of the anode terminal than in the case of vertical welding. It is easy to adhere to the part and welding work becomes easy.

[0013]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a solid electrolytic capacitor 1 according to an embodiment of the invention of claim 1.
FIG. 2 is a rectangular capacitor element,
A fine powder of tantalum is compression molded and sintered, and an anode body formed by sintering is formed with an anode oxide film, a solid electrolyte layer such as manganese dioxide, and a cathode layer including a carbon layer and a conductive silver paste layer. Further, as shown in FIG. 2, the capacitor element 2 is provided with a step portion 4 extending from one side surface to the other side surface at the end of the bottom portion 3. In addition, the capacitor element 2
An anode lead wire 6 made of tantalum or the like is drawn out from the upper portion 5 of the. Reference numeral 7 denotes an exterior, which is formed by transfer molding of epoxy resin. 8
Is an anode terminal, which is resistance-welded to the anode lead wire 6 and bent along the peripheral surface of the exterior 7 toward the bottom surface.
Reference numeral 9 denotes a cathode terminal, the tip of which is arranged on the step portion 4 of the capacitor element 2 and connected to the cathode layer by the conductive fixing paste 10. is there.

The step portion 4 is the bottom portion 3 of the capacitor element 2.
May extend from to the top.

According to the above embodiment, since the cathode terminal 9 is connected to the cathode layer at the step 4 of the bottom 3 of the capacitor element 2, it does not protrude from the side surface 11 of the capacitor element 2 but the side surface thereof. 11 can be arranged on substantially the same plane.

FIG. 3 is a perspective view of a capacitor element 12 used in another embodiment of the first aspect of the invention. The capacitor element 12 particularly has a step portion 14 formed at the center of the end of the bottom portion 13. This step 14 may extend towards the upper part 15 of the capacitor element 12. The capacitor element 12 has a step portion 14 as compared with the capacitor element 2 of FIG.
Since it is short, the capacity can be increased. Further, the solid electrolytic capacitor using the capacitor element 12 can be made smaller. However, since the step portion 14 of the capacitor element 12 has a narrow width, it is relatively difficult to arrange and connect the tip of the cathode terminal to the step portion 14. In this respect, since the capacitor element 2 of FIG. 2 has the step portion 4 having a long width, such a work can be facilitated.

FIG. 4 also shows a perspective view of a capacitor element 16 used in another embodiment. The capacitor element 16 has a concave portion 18 between the center and the end of the bottom portion 17. Then, as shown in FIG. 5, the tip of the cathode terminal 19 is put in the concave portion 18 of the capacitor element 16 and is connected to the cathode layer by the conductive fixing paste 20. In addition, the capacitor element 16
A lead wire 21 for an anode is drawn out from the above, and an anode terminal 22 is resistance-welded to the lead wire 21 to mold a resin to form an outer package 23 to form a solid electrolytic capacitor 24. Therefore, the cathode terminal 19 is located at the bottom portion 17 of the capacitor element 16 in FIG.
There is no need to bend like. Therefore, in the solid electrolytic capacitor 24, the capacitor element 16 can be lengthened by the thickness of the cathode terminal 19 to increase the capacity, or the exterior can be thinned to be miniaturized.

FIG. 6 also shows a perspective view of a capacitor element 25 used in another embodiment. The capacitor element 25 has a recess 27 extending from one side surface to the other side surface between the center and the end of the bottom portion 26. Then, the tip of the cathode terminal is put into the recess 27, connected, and the cathode terminal is pulled out from the exterior. In this capacitor element 25, the width of the recess 27 is longer than that of the capacitor element 16 of FIG. Therefore, the work of connecting the cathode terminal becomes easier. However, it is smaller than the capacitance capacitor element 16, and the effect of downsizing is low.

Next, an embodiment of the invention of claim 2 is shown in FIG. The capacitor element of this embodiment is the same as that shown in FIG.
In particular, the anode lead wire 6 is obliquely penetrated into the notch 29 (or hole) provided in the anode terminal 28, and the tip of the anode lead wire 6 is irradiated with laser light and welded. The anode terminal 28 is bent from the welding point 30 at the tip, is drawn straight out to the exterior, and is further bent along the exterior 31.

According to this embodiment, since the anode terminal 28 is welded to the anode lead wire 6, the anode lead wire 6 can be made short. Therefore, the capacity of the capacitor element 2 can be increased and the capacity can be increased. Then, the solid electrolytic capacitor 32 can be made smaller. Further, since the anode terminal 28 is obliquely welded, workability is improved.

FIG. 8 shows another embodiment of the invention of claim 2. Also in this embodiment, the same capacitor element 2 as in FIG. 2 is used. And, in particular, the step portion 4 is covered by the exterior 3
The capacitor element 2 is arranged near the bottom side of the capacitor element 3. Therefore, the cathode terminal 34 is connected to the step portion 4,
It is pulled out from a position close to the bottom surface of the exterior 33. Also,
Notch 36 with anode lead wire 6 provided in anode terminal 35
It is penetrated diagonally and welded by laser light. Then, the anode terminal 35 extends toward the bottom surface of the outer casing 33 and is pulled out from the bent outer casing 33 in the middle.

Also in this embodiment, since the anode lead wire 6 is obliquely penetrated through the anode terminal 35 and welded by laser light, the capacity can be increased, the size can be reduced, and the welding work can be performed relatively easily. An easy solid electrolytic capacitor 37 can be obtained.

Further, FIG. 9 also shows an embodiment of the invention of claim 2. In this embodiment, the capacitor element 38 having the shape shown in FIG. 4 or 6 is used. Then, the cathode terminal 39 is connected to the concave portion 40 formed in the capacitor element 38 with the conductive fixing paste 41, and is drawn out from the exterior 42.
Further, the anode terminal 43 is formed by obliquely penetrating an anode lead wire 45 into a notch 44 provided in the anode terminal 43, welding it with a laser beam, bending it near a welding point 46, and drawing it out from the exterior 42. In addition, the welding point 4 of this anode terminal 43
The inclination of the portion including 6 is made substantially equal to the inclination of the exterior 42.

Also in the case of this embodiment, the capacity can be increased,
A solid electrolytic capacitor 47 which can be downsized and has good welding workability can be obtained. Moreover, since the inclination of the portion including the welded portion 46 is made substantially equal to the inclination of the exterior 42, the exterior 4
The thickness of 2 can be reduced. Therefore, the capacity can be increased or the size can be reduced.

Next, for the example and the conventional example, the rating is 7
Using a molded chip type tantalum solid electrolytic capacitor having V, length 5.6 mm, height 3.1 mm and width 4.5 mm, the volume ratio of the capacitor element and the capacitance of each capacitor were determined. The formation voltage of the capacitor element is 39V. Also,
The number of samples is 2000 each. The volume ratio is the ratio when the value of Conventional Example 1 is 1.00, and the capacitance of the capacitor is the measured value when the rated voltage is 7V.

[0026]

[Table 1]

As is clear from Table 1, according to Examples 1 to 7, the volume ratio of the capacitor element is 1.5 times the maximum and the capacitance of the capacitor is the minimum value as compared with the conventional examples 1 to 3. About 1.26 to 1.56 times, maximum value about 1.20 to 1.5
It will be 5 times. Further, according to Embodiment 4 to Embodiment 7 of the invention of Claim 2, the volume ratio is about 1.12 times at maximum and the capacity is minimum as compared with Embodiment 1 to Embodiment 3 of the invention of Claim 1. The value is about 1.02 to 1.13 times, and the maximum value is about 1.00 to 1.14 times.

[0028]

As described above, according to the invention of claim 1,
Since at least the bottom portion of the anode body is provided with a stepped portion or a recessed portion and the cathode terminal is connected to this stepped portion or the like, it is possible to obtain a solid electrolytic capacitor capable of increasing the capacity and downsizing.

According to the second aspect of the present invention, in addition to the above structure, the anode lead wire is obliquely penetrated through the anode terminal and welded by laser light, so that the capacity is increased more effectively. Can be made smaller and smaller, and the work is easier than when vertically welded with a laser beam, and when resistance welding is performed vertically, the welding lead electrode may bend the anode lead wire or anode terminal. However, there is obtained a solid electrolytic capacitor capable of preventing such a defect.

[Brief description of drawings]

1 shows a sectional view of an embodiment of the invention of claim 1;

FIG. 2 shows a perspective view of a capacitor element according to an embodiment of the present invention.

FIG. 3 shows a perspective view of a capacitor element according to another embodiment of the present invention.

FIG. 4 shows a perspective view of a capacitor element according to another embodiment of the present invention.

FIG. 5 shows a sectional view of another embodiment of the invention of claim 1.

FIG. 6 shows a perspective view of a capacitor element according to another embodiment of the present invention.

FIG. 7 shows a sectional view of an embodiment of the invention of claim 2;

FIG. 8 is a sectional view of another embodiment of the invention of claim 2;

FIG. 9 shows a sectional view of another embodiment of the invention of claim 2.

FIG. 10 shows a sectional view of a conventional example.

FIG. 11 shows a sectional view of a conventional example.

FIG. 12 shows a cross-sectional view of a conventional example.

[Explanation of symbols]

1, 24, 32, 37, 47 ... Solid electrolytic capacitors,
2, 12, 16, 25, 38 ... Capacitor element, 4,
14 ... Step portion, 6, 21, 45 ... Anode lead wire, 8,
22, 28, 35, 43 ... Anode terminal, 9, 19, 3
4, 39 ... Cathode terminal, 18, 27, 40 ... Recessed portion.

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[Procedure amendment]

[Submission date] July 21, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

Claims (2)

[Claims] 1. A solid electrolytic capacitor in which an anodic oxide film, a solid electrolyte layer and a cathode layer are provided on an anode body made of a valve metal, from which an anode lead wire is drawn, to form a capacitor element, and a cathode terminal is connected to the cathode layer. A solid electrolytic capacitor comprising: an anode body having a step or a recess at least on a bottom thereof, and a cathode terminal connected to a cathode layer in the step or the recess. 2. The solid electrolytic capacitor according to claim 1, further comprising a cathode terminal which is obliquely penetrated through the anode lead wire and which is welded to the anode lead wire by laser light.