JP2005328100A - Method for manufacturing solid electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact chip capacitor with large capacity. <P>SOLUTION: In a solid electrolytic capacitor, first and second conductive sheets are arranged separated from each other, an insulating sheet is provided between the first and second conductive sheets, a capacity device, from one end of which an anode lead is guided out and on an outer circumferential surface of which a cathode is formed, is mounted on the insulating sheet; and at the same time, the anode lead of the capacitor device is connected to the first conductive sheet, the cathode of the capacitor device is connected to the second conductive sheet, and the capacity device is sealed by coating resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a chip capacitor in which a volume ratio of a capacitor element to a capacitor finished product is improved in a chip type solid electrolytic capacitor.

  As shown in FIG. 3, a conventional solid electrolytic capacitor has a dielectric oxide film, a solid oxide on a sintered body or the like (for example, tantalum sintered body) made of a valve metal having an anode lead (11) led to one end. An electrolyte layer, a carbon layer, and a silver paste layer are sequentially formed to complete the capacitor element (2).

  Next, of the two lead frames (21) and (22) bent in advance to a predetermined dimension, one lead frame (21) is welded to the anode lead (11), and the other lead frame (22) is joined to silver. An adhesive (4) is adhesively connected to the silver paste layer.

  Next, the capacitor element (2) is resin-sealed by a transfer mold or the like so that the tip ends of the lead frames (21) and (22) are exposed.

Finally, lead frames (21) and (22) led out of the exterior resin (6) are bent to predetermined dimensions to form a plus electrode and a minus electrode, thereby completing a capacitor.
JP 59-194421 A

  In such a conventional solid electrolytic capacitor, the welding allowance (23) for connecting the anode lead (11) and the lead frame (21) is provided on the positive electrode side, and the bending allowance for the lead frame (22) is provided on the negative electrode side. It is necessary to take (24). For example, in the case of a capacitor having a length of 7.3 mm and a width of 4.3 mm (hereinafter referred to as “D case”), the thicknesses L1 and L2 of the exterior electrode (6) on the plus electrode side and the minus electrode side are respectively It was about 1.8 mm.

  Also, conventionally, it is necessary to bend the lead frames (21) and (22) outside the exterior resin (6), and the length of the exterior resin (6) after molding is 7.3 mm from the standard value of 7.3 mm for the D case. Therefore, it was necessary to mold the lead frame (21) and (22) as small as possible (see FIG. 3). In the above example, the length of the exterior resin (6) after molding is molded to 7.1 mm.

  For this reason, in the prior art, the volume ratio of the capacitor element to the finished capacitor product (hereinafter simply referred to as “volume ratio”) cannot be sufficiently large, and the volume ratio is about 20.4 as shown in Table 1 below. It stopped at about%. Table 1 shows an example in which a capacitor having a height of 1.8 mm is completed in the D case.

  Accordingly, the present invention provides a chip capacitor that can be reduced in size and increased in capacity by improving the volume ratio.

In order to solve the above problems, the solid electrolytic capacitor according to the present invention includes a step of forming an opening in the conductive sheet that separates the conductive sheet into a first conductive sheet region and a second conductive sheet region, and from one end. Arranging a plurality of capacitor elements having an anode lead led out and having a cathode formed on the outer peripheral surface thereof across the opening on the conductive sheet; and each anode lead of the plurality of capacitor elements in the first Connecting to the conductive sheet region, connecting each cathode of the plurality of capacitor elements to the second conductive sheet region, and forming an exterior resin layer so as to integrally cover the plurality of capacitor elements; Cutting the exterior resin layer and the conductive sheet at positions away from the tips of the anode leads and the outer peripheral surfaces of the cathodes of the capacitor elements. And wherein the door.

In addition, an insulating sheet is disposed on the conductive sheet across the opening, and the plurality of capacitor elements are arranged on the insulating sheet.
A step of providing a plurality of first conductive sheet regions and a plurality of second conductive sheet regions in the conductive sheet, and forming the exterior resin layer and then cutting the exterior resin layer and the conductive sheet vertically and horizontally; It is characterized by providing.

As described above, according to the present invention, the volume ratio can be increased, and a small-sized and large-capacity solid electrolytic capacitor can be realized.

  Further, since the lead frames (21) and (22) are not bent as in the prior art, a capacitor having a small series inductor component (ESL) can be realized.

  In the solid electrolytic capacitor, as shown in FIG. 6, the anode lead (11) is led out at one end, and the capacitor element (2) having the cathode formed on the outer peripheral surface is sealed with resin.

  Capacitor element (2) produces a dielectric oxide film on the surface of a valve metal such as tantalum (Ta), aluminum (Al), niobium (Nb), titanium (Ti), etc. by a method such as anodic oxidation. A polymer organic semiconductor such as polypyrrole, polythiophene or polyaniline is formed as a solid electrolyte on the film, and then a carbon layer and a silver paste layer are sequentially formed to complete. Since such a capacitor element (2) can be produced by a known technique such as Japanese Patent Laid-Open No. 8-148392, description of the method for producing the capacitor element itself is omitted.

In the following examples, tantalum sintered body (1) was adopted as the valve action metal, and polypyrrole was adopted as the solid electrolyte.
(Example 1)
FIG. 1 shows a first embodiment of a solid electrolytic capacitor according to the present invention.

  In FIG. 1, (2) is a capacitor element in which an anode lead (11) is led out from one end, and (31) and (32) are conductive sheets in which Ni alloy and solder plating are sequentially applied to the surface of 42 alloy (iron nickel alloy). The cathode of the capacitor element (2) (silver paste layer on the outer peripheral surface) is connected to one conductive sheet (32) via a conductive adhesive (4), and the anode lead is welded to the other conductive sheet (31). Alternatively, they are connected via a conductive adhesive. (5) is an insulating sheet disposed between the capacitor element (2) and the conductive sheets (31) and (32) and electrically insulating the conductive sheets (31) and (32); ) Is an exterior resin made of epoxy resin or the like and sealing the capacitor element (2).

  Next, the manufacturing method of the first embodiment will be described.

  First, as shown in FIG. 4, a conductive sheet (3) having openings (33) and (33) is prepared, and an insulating sheet (5) made of an adhesive tape straddling the openings (33) and (33). (5) is arranged. Next, the capacitor elements (2) and (2) are arranged on the insulating sheets (5) and (5), and the cathode (silver paste layer on the outer peripheral surface) is attached to the conductive sheet (3) with the conductive adhesive (4). After connecting, the anode leads (11) and (11) are appropriately bent, and then connected by welding or a conductive adhesive (see FIG. 1). Here, in this example, the width of the openings (33) and (33) of the conductive sheet (3) is 3.0 mm, the width of the insulating sheets (5) and (5) is 3.5 mm, and the capacitor element (2) ( The length of 2) (left and right direction in FIG. 4) was 5.0 mm.

  Thereafter, an exterior resin (6) made of an epoxy resin or the like is applied on the conductive sheet (3) so as to cover the capacitor elements (2) and (2), and heat-treated in a curing furnace at 150 ° C. for 30 minutes. The exterior resin (6) is cured. In this example, the height of the exterior resin (6) was 1.6 mm.

Finally, the solid electrolytic capacitor of this embodiment is completed by dicing the positions of the anode leads of the plurality of capacitor elements and the positions away from the outer peripheral surfaces of the cathodes along the one-dot chain line in the drawing. . In the present example, the dimensions of the capacitor were D case (7.3 mm × 4.3 mm).
(Example 2)
FIG. 2 shows a second embodiment of the solid electrolytic capacitor according to the present invention. In FIG. 2, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the second embodiment, a cut and raised portion (34) is provided at the end of the conductive sheet (31), and the anode lead (11) is press-fitted into a notch (not shown) provided with the cut and raised portion (34). Connected.

  In the manufacture of the second embodiment, first, as shown in FIG. 5, a conductive sheet (3) having openings (33) and (33) and cut and raised portions (34) and (34) is prepared. The openings (33) and (33) are closed with an insulating sheet (5) made of an adhesive tape. Next, the capacitor elements (2) and (2) are arranged on the insulating sheets (5) and (5), and the cathode (silver paste layer on the outer peripheral surface) is applied to the conductive sheet (3) with the conductive adhesive (4). Then, the anode leads (11) and (11) are press-fitted and connected to notches (not shown) provided in the cut and raised portions (34) and (34). Here, in this example, the width of the openings (33) and (33) of the conductive sheet (3) is 3.0 mm, the width of the insulating sheets (5) and (5) is 3.5 mm, and the capacitor element (2) ( The length of 2) (left and right direction in FIG. 5) was 5.8 mm.

Thereafter, the capacitor elements (2) and (2) are sealed with the exterior resin (6) in the same manner as in Example 1, and separated from the tips of the anode leads and the outer peripheral surfaces of the cathodes of the plurality of capacitor elements. The solid electrolytic capacitor was completed by dicing at the position. In this example, as in the first example, the height of the exterior resin (6) was 1.6 mm, and the dimensions of the capacitor were D case.
In the first and second embodiments according to the present invention, it is not necessary to bend the lead frames (21) and (22) outside the exterior resin (6) in the length direction of the solid electrolytic capacitor as in the conventional example shown in FIG. Therefore, the size of the exterior resin (6) can be increased, and the welding allowance (23) between the lead frame (21) and the anode lead (11) and the bending allowance (24) of the lead frame (22) are not required. The dimension of the capacitor element (2) sealed in the exterior resin (6) can be increased. Table 2 shows the relationship between specific dimensions in the length direction of these examples and the conventional example.

  As shown in Table 2, in Examples 1 and 2, the outer dimension of the exterior resin (6) was 7.3 mm, which was 0.2 mm longer than the conventional example, and the length of the capacitor element (2) In this case, 1.5 mm in Example 1 and 2.3 mm in Example 2 could be made larger than the conventional example.

  Next, Table 3 shows the relationship between specific dimensions in the height direction of these examples and the conventional example.

As shown in Table 3, in Examples 1 and 2, the thicknesses of the lead frame (22) covering the upper surface of the capacitor element (2) and the lead frames (21) and (22) bent so as to contact the lower surface in the conventional example are as follows. Since it becomes unnecessary, the height of the capacitor element (2) can be increased by 0.3 mm compared to the conventional example. In addition, each dimension of the width direction does not change in these Examples and conventional examples.

  As described above, the volume and volume ratio of the capacitor element (2) used in Examples 1 and 2 are as shown in Table 4.

  As shown in Table 4, in Example 1, the volume of the capacitor element (2) was 1.86 times that in the conventional example, and in Example 2, it was 2.15 times.

It is sectional drawing of the solid electrolytic capacitor by Example 1 of this invention. It is sectional drawing of the solid electrolytic capacitor by Example 2 of this invention. It is sectional drawing of the solid electrolytic capacitor by a prior art. It is a top view for demonstrating the manufacturing method of Example 1 of this invention. It is a top view for demonstrating the manufacturing method of Example 2 of this invention. 1 is a perspective view of a capacitor element according to the present invention.

Explanation of symbols

2 Capacitor element 3, 31, 32 Conductive sheet 4 Conductive adhesive 5 Insulating material 6 Exterior resin

Claims (3)

  A step of forming an opening for separating the conductive sheet into a first conductive sheet region and a second conductive sheet region in the conductive sheet, and a plurality of anode leads led out from one end and a cathode formed on the outer peripheral surface Arranging the capacitor elements on the conductive sheet across the opening, connecting each anode lead of the plurality of capacitor elements to the first conductive sheet region, and each cathode of the plurality of capacitor elements Connecting the second conductive sheet region to the second conductive sheet region, forming an exterior resin layer so as to integrally cover the plurality of capacitor elements, and tips of the anode leads and outer peripheries of the cathodes of the capacitor elements And a step of cutting the exterior resin layer and the conductive sheet at a position away from the surface.   The method for producing a solid electrolytic capacitor according to claim 1, wherein an insulating sheet is disposed across the opening on the conductive sheet, and the plurality of capacitor elements are arranged on the insulating sheet. A plurality of first conductive sheet regions and a plurality of second conductive sheet regions are provided in the conductive sheet,
And a step of cutting the exterior resin layer and the conductive sheet vertically and horizontally after forming the exterior resin layer.

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