JP2010177467A - Solid-state electrolytic capacitor element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state electrolytic capacitor element wherein deterioration in an electrolyte layer is suppressed without increasing equivalent series resistance (ESR). <P>SOLUTION: In the solid-state electrolytic capacitor element, a dielectric layer 12 is formed on an outer circumferential surface of an anode body 11, and a segmenting member 16 for segmenting an outer circumferential surface of the dielectric layer 12 into two regions 12a and 12b is disposed on the outer circumferential surface of the anode body 11, and an electrolyte layer 13 and a cathode layer 14 are formed in this order on the dielectric layer 12 in one region 12b out of two regions 12a and 12b, and an insulating portion 17 is formed over respective surfaces of the cathode layer 14 and the segmenting member 16. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solid electrolytic capacitor element.

  In the conventional solid electrolytic capacitor element, as shown in FIG. 4, a dielectric layer 102 is formed on the outer peripheral surface of a foil-like anode body 101, and the outer peripheral surface of the dielectric layer 102 is formed on the dielectric layer 102. Is formed into two regions 102a and 102b (see, for example, Patent Document 1). An electrolyte layer 103, a carbon layer 104, and a silver paste layer 105 are formed in this order on the dielectric layer 102 in one of the two regions 102a and 102b divided by the sorting member 106.

  Conventionally, since the dielectric layer 102 has been formed very thin, when the defect portion such as a crack exists in the dielectric layer 102 or in the manufacturing process of the solid electrolytic capacitor element, the defect is present in the dielectric layer 102. Part may occur. For this reason, when the carbon layer 104 or the silver paste layer 105 formed on the electrolyte layer 103 is in direct contact with the dielectric layer 102, there is a possibility that leakage current increases in the solid electrolytic capacitor.

  Therefore, as shown in FIG. 4, it has been proposed to form the carbon layer 104 and the silver paste layer 105 on the electrolyte layer 103 so as not to contact the sorting member 106.

JP-A-7-94369

  However, in the conventional solid electrolytic capacitor element, a part of the electrolyte layer 103 may be exposed without being covered with the carbon layer 104 and the silver paste layer 105. As shown in FIG. 4, when a part of the electrolyte layer 103 is exposed, the part is deteriorated by the influence of water, oxygen, etc., and the capacitance of the solid electrolytic capacitor element is reduced or the equivalent series resistance (ESR). May increase.

  Therefore, as shown in FIG. 5, it is conceivable to cover a portion of the electrolyte layer 103 near the sorting member 106 with an insulating portion 107 made of an insulating material. As a result, even when a part of the electrolyte layer 103 is not covered with the carbon layer 104 and the silver paste layer 105, the part is covered with the insulating portion 107, so that the deterioration of the electrolyte layer 103 is prevented. Will be.

  However, in the solid electrolytic capacitor element, a part of the insulating portion 107 is interposed between the carbon layer 104 and the electrolyte layer 103 as shown in FIG. The area is reduced. Therefore, the solid electrolytic capacitor shown in FIG. 5 has a problem that the equivalent series resistance (ESR) increases.

  Accordingly, an object of the present invention is to provide a solid electrolytic capacitor element in which deterioration of an electrolyte layer is suppressed without increasing an equivalent series resistance (ESR).

  In the solid electrolytic capacitor element according to the present invention, the dielectric layer (12) is formed on the outer peripheral surface of the anode body (11), and the outer peripheral surface of the dielectric layer (12) is divided into two regions (12a, 12b). ) Is provided, and one of the two regions (12a, 12b) (12b) includes an electrolyte layer (13) and a cathode layer on the dielectric layer (12). (14) are formed in this order, and an insulating portion (17) is formed on each surface of the cathode layer (14) and the sorting member (16) across the both surfaces.

Of course, the cathode layer (14) and the sorting member (16) are separated from each other, and even if the cathode layer (14) and the sorting member (16) are in contact with each other, the cathode layer A slight gap leading to the surface of the electrolyte layer is formed between (14) and the sorting member (16). However, in the solid electrolytic capacitor, since the insulating portion (17) is formed across the surfaces of the cathode layer (14) and the sorting member (16), the gap is blocked from the outside air. . Accordingly, water and oxygen are unlikely to enter the gap, and as a result, deterioration of the electrolyte layer (13) due to the influence of water, oxygen and the like is suppressed.
Further, in the solid electrolytic capacitor, since the insulating portion (17) is formed on the surface of the cathode layer (14), the presence of the insulating portion (17) causes the electrolyte layer (13) and the cathode layer (14) to be separated. The contact area does not decrease. Therefore, even when compared with the conventional solid electrolytic capacitor element, the contact area between the cathode layer (14) and the electrolyte layer (13) is hardly reduced. Therefore, the equivalent series resistance (ESR) is sufficiently small in the solid electrolytic capacitor. ) Can be obtained.

  In the specific configuration of the solid electrolytic capacitor element, the cathode layer (14) and the sorting member (16) are separated from each other, and an insulating portion is provided between the cathode layer (14) and the sorting member (16). A part of (17) is interposed in a state of covering the surface of the electrolyte layer (13), and the insulating part (17) is interposed between the cathode layer (14) and the electrolyte layer (13). Absent.

In the solid electrolytic capacitor, the electrolyte layer (13) is covered with the cathode layer (14), while the portion of the electrolyte layer (13) that is not covered with the cathode layer (14) is the cathode layer (14). It will be covered with an insulating part (17) interposed between the sorting member (16). Therefore, the electrolyte layer (13) is shielded from the outside air, and as a result, deterioration of the electrolyte layer (13) due to the influence of water, oxygen and the like is suppressed.
In the solid electrolytic capacitor, since the insulating portion (17) is not interposed between the cathode layer (14) and the electrolyte layer (13), the presence of the insulating portion (17) causes the electrolyte layer (13). The contact area between the cathode layer and the cathode layer (14) does not decrease. Therefore, even when compared with the conventional solid electrolytic capacitor element, the contact area between the cathode layer (14) and the electrolyte layer (13) is hardly reduced, and therefore the sufficiently low equivalent series resistance (ESR) in the solid electrolytic capacitor. ) Can be obtained.

In another specific configuration of the solid electrolytic capacitor element, the insulating portion (17) is made of resin.
A second cathode layer (15) different from the cathode layer (14) is formed on the cathode layer (14), and the outer peripheral surface of the cathode layer (14) is formed on the insulating portion (17). ) And the second cathode layer (15).

  In the solid electrolytic capacitor element according to the present invention, the deterioration of the electrolyte layer is suppressed without increasing the equivalent series resistance (ESR).

It is (a) sectional drawing and (b) top view which show the solid electrolytic capacitor element which concerns on one Embodiment of this invention. It is sectional drawing which shows the example of the improved form of the said solid electrolytic capacitor. It is sectional drawing which shows the solid electrolytic capacitor carrying the said solid electrolytic capacitor element. It is sectional drawing which shows an example of the conventional solid electrolytic capacitor element. It is sectional drawing which shows the other example of the conventional solid electrolytic capacitor element.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
A capacitor element according to an embodiment of the present invention includes a foil-like anode body 11 formed of a metal having a valve action (hereinafter referred to as a valve action metal) as shown in FIG. On the outer peripheral surface, a dielectric layer 12 is formed, and a dividing member 16 is provided for dividing the outer peripheral surface of the dielectric layer 12 into two regions 12a and 12b.

  For example, aluminum, tantalum, niobium, titanium, or the like is used as the valve metal that forms the anode body 11. Further, the sorting member 16 is made of a fluororesin, a fluorine derivative, a polymer or the like, and is difficult to wet with an alcohol solvent. The material of the sorting member 16 is not limited to these, and various insulating materials such as an epoxy resin can be used as the material.

  The dielectric layer 12 is composed of an oxide film formed on the outer peripheral surface of the anode body 11, and the oxide film is obtained by immersing the anode body 11 in an electrolytic solution such as a phosphoric acid aqueous solution or an adipic acid aqueous solution. 11 is formed by electrochemically oxidizing (anodic oxidation) the outer peripheral surface.

  The anode body 11 having the dielectric layer 12 formed on the outer peripheral surface may be manufactured as follows. First, an oxide film is formed by anodic oxidation on the entire surface of the anode foil wound in a roll shape, and then the anode foil is cut into a predetermined size, and then an oxide film is formed on the cut surface. Thereby, the anode body 11 in which the oxide film to be the dielectric layer 12 is formed on the outer peripheral surface is manufactured.

The electrolyte layer 13 and the carbon layer 14 are formed on the dielectric layer 12 in this order in one region 12b of the two regions 12a and 12b divided by the sorting member 16.
The electrolyte layer 13 is formed so that the end thereof is in contact with the sorting member 16. As a material for forming the electrolyte layer 13, a TCNQ (Tetracyano-quinodimethane) complex salt, a conductive polymer, or the like is used. Examples of the conductive polymer include polypyrrole, polythiophene, polyfuran, and polyaniline.

  The electrolyte layer 13 is formed by immersing one region 12b of the outer peripheral surface of the dielectric layer 12 in a chemical polymerization solution. The electrolyte layer 13 may be formed by immersing the one region 12b in the electrolytic solution. In this case, the electrolyte layer 13 is formed by an electrolytic reaction.

  The carbon layer 14 is formed on the electrolyte layer 13 so that the end thereof is in contact with the sorting member 16. Even when the carbon layer 14 and the sorting member 16 are in contact with each other, a slight gap leading to the surface of the electrolyte layer 13 between the carbon layer 14 and the sorting member 16, specifically, water or oxygen Gaps that allow the passage of are formed in various places.

  As shown to Fig.1 (a), the insulating part 17 is formed in the surface of each of the carbon layer 14 and the division member 16 ranging over both surfaces. The insulating portion 17 is made of a resin such as an epoxy resin, for example.

The insulating part 17 is formed as follows. After the carbon layer 14 is formed on the electrolyte layer 13, a resin is applied to the surfaces of the carbon layer 14 and the sorting member 16 so that the boundary between both surfaces is covered, and the resin is cured.
Note that the gap formed between the carbon layer 14 and the sorting member 16 is narrow, and almost no resin can enter. Therefore, an insulating portion 17 may be interposed between the carbon layer 14 and the electrolyte layer 13. Absent.

A silver paste layer 15 is formed on the carbon layer 14, and the outer peripheral surface of the carbon layer 14 is covered with the insulating portion 17 and the silver paste layer 15.
Therefore, in the solid electrolytic capacitor element according to the present embodiment, the cathode layer made of the carbon layer 14 and the second cathode layer made of the silver paste layer 15 are formed on the electrolyte layer 13 in this order. These cathode layers constitute the cathode portion 1b of the solid electrolytic capacitor element. On the other hand, the anode portion 1a of the solid electrolytic capacitor element is constituted by a portion of the anode body 11 where the cathode layer is not formed.

  In the above-described solid electrolytic capacitor element, as shown in FIGS. 1 (a) and 1 (b), the insulating portion 17 is formed across the surfaces of the carbon layer 14 and the partitioning member 16, so that the carbon A slight gap formed between the layer 14 and the separating member 16 is blocked from the outside air. Accordingly, water and oxygen are unlikely to enter the gap, and as a result, deterioration of the electrolyte layer 13 due to the influence of water, oxygen and the like is suppressed.

  In the solid electrolytic capacitor, since the insulating portion 17 is not interposed between the carbon layer 14 and the electrolyte layer 13 as described above, the presence of the insulating portion 17 causes the electrolyte layer 13 and the cathode layer 14 to be separated from each other. The contact area does not decrease. Therefore, compared with the conventional solid electrolytic capacitor element, the contact area between the carbon layer 14 and the electrolyte layer 13 is hardly reduced, and thus a sufficiently small equivalent series resistance (ESR) is obtained in the solid electrolytic capacitor. I can do it.

FIG. 2 is a cross-sectional view showing an example of an improved form of the solid electrolytic capacitor. As shown in FIG. 2, the carbon layer 14 may be formed on the electrolyte layer 13 such that the end thereof does not contact the sorting member 16. For example, by forming the sorting member 16 from a material having water repellency, the end portion of the carbon layer 14 is less likely to contact the sorting member 16.
In this case, a gap is formed between the carbon layer 14 and the sorting member 16, and immediately after the carbon layer 14 is formed, the electrolyte layer 13 is positioned near the sorting member 16. The portion is exposed without being covered with the carbon layer 14.

  Therefore, in the solid electrolytic capacitor according to the improved embodiment, as shown in FIG. 2, a part of the insulating portion 17 is interposed between the carbon layer 14 and the partitioning member 16, and the surface of the electrolyte layer 13 is formed by the part. An insulating portion 17 is formed so as to be covered.

  The insulating part 17 is formed as follows. After the carbon layer 14 is formed on the electrolyte layer 13, a resin is filled into a gap formed between the carbon layer 14 and the sorting member 16. At this time, the resin is applied so that the surfaces of the carbon layer 14 and the sorting member 16 are covered with a part of the resin around the gap.

  In the solid electrolytic capacitor element according to the improved embodiment, as shown in FIG. 2, the electrolyte layer 13 is covered with the carbon layer 14, while the portion of the electrolyte layer 13 that is not covered with the carbon layer 14 is the carbon layer 14. And the insulating member 17 interposed between the partitioning members 16. Therefore, the electrolyte layer 13 is shielded from the outside air, and as a result, deterioration of the electrolyte layer 13 due to the influence of water, oxygen, or the like is suppressed.

  Further, in the solid electrolytic capacitor, as in the solid electrolytic capacitor shown in FIG. 1, since the insulating portion 17 is not interposed between the carbon layer 14 and the electrolyte layer 13, a sufficiently small equivalent series resistance ( ESR) can be obtained.

FIG. 3 is a cross-sectional view showing a solid electrolytic capacitor on which the above-described solid electrolytic capacitor element is mounted. In FIG. 3, the solid electrolytic capacitor element is denoted by reference numeral 1.
In the solid electrolytic capacitor shown in FIG. 3, the solid electrolytic capacitor element 1 is electrically connected to the upper surface and the lower surface of the anode terminal 3 and the cathode terminal 4. Specifically, the anode portion 1a of the solid electrolytic capacitor element 1 is electrically connected to the anode terminal 3 by spot welding, and the cathode portion 1b of the solid electrolytic capacitor element 1 is electrically connected to the cathode terminal 4 by a conductive adhesive. Connected.

  Further, in the solid electrolytic capacitor shown in FIG. 3, two solid electrolytic capacitor elements 1 and 1 are sequentially laminated on the solid electrolytic capacitor element 1 connected to the upper surfaces of the anode terminal 3 and the cathode terminal 4. In the adjacent solid electrolytic capacitor elements 1, 1, the anode portions 1a, 1a are electrically connected to each other by spot welding, and the cathode portions 1b, 1b are electrically connected to each other by a conductive adhesive. .

  The plurality of solid electrolytic capacitor elements 1 mounted on the solid electrolytic capacitor are covered with an exterior resin 2. A part of the anode terminal 3 is exposed from the exterior resin 2, and the part is bent so that the end of the anode terminal 3 is located along the lower surface of the exterior resin 2. Further, a part of the cathode terminal 4 is exposed from the exterior resin 2, and the part is bent so that the end of the cathode terminal 4 is located along the lower surface of the exterior resin 2.

  The inventor of the present application has confirmed by the experiment using the solid electrolytic capacitor shown in FIG. 3 that the deterioration of the electrolyte layer 13 is suppressed without increasing the equivalent series resistance (ESR) in the above-described solid electrolytic capacitor element. ing.

In this experiment, a solid electrolytic capacitor sample S1 mounted with the solid electrolytic capacitor element shown in FIG. 2, a solid electrolytic capacitor sample S2 mounted with the conventional solid electrolytic capacitor element shown in FIG. 4, and the solid electrolytic capacitor shown in FIG. 1000 pieces of solid electrolytic capacitors S3 each equipped with a capacitor element were facilitated.
In the conventional solid electrolytic capacitor element shown in FIG. 4, a part of the electrolyte layer 103 is exposed without being covered with the carbon layer 104. In the solid electrolytic capacitor element shown in FIG. 5, a part of the electrolyte layer 103 exposed in the solid electrolytic capacitor shown in FIG. 4 is covered with the insulating portion 107, but the insulating portion 107 includes the carbon layer 104 and the electrolyte layer. 103.

In any of the samples S1 to S3, an aluminum foil is used as the anode body 11, and an aluminum oxide (Al ₂ O ₃ ) film that becomes the dielectric layer 12 is formed on the outer peripheral surface of the anode body 11 by 0.01 wt% to ₂ wt%. The phosphoric acid aqueous solution or adipic acid aqueous solution was used. In addition, the sorting member 16 is formed of a fluorine derivative, and a polythiophene layer to be the electrolyte layer 13 is formed in the region 1b separated by the sorting member 16 with 3,4-ethylenedioxythiophene, iron P-toluenesulfonate (III ), A chemical polymerization solution composed of 1-butanol.
In all of the samples S1 to S3, the outer dimensions are 4.3 mm in width, 7.3 mm in length, 2.0 mm in thickness, and the capacitance at a rated voltage of 25 V is 10 μF.

In this experiment, for each of the prepared samples S1 to S3, an electrostatic capacity (Cap) when the frequency is 120 Hz and an equivalent series resistance (ESR) when the frequency is 100 kHz are measured at room temperature and 105 ° C. using an LCR meter. Measured at a temperature of. In addition, about the measurement under the temperature of 105 degreeC, it continuously performed for 2000 hours or more.
And the change rate of the electrostatic capacitance when 1000 hours passed from the measurement start at the temperature of 105 degreeC and 2000 hours passed was calculated | required by (DELTA) Cap / Cap. Here, Cap represents the capacitance at the start of measurement, and ΔCap represents the amount of change in capacitance when 1000 hours or 2000 hours have elapsed from the start of measurement. Further, the change amount ΔESR of the equivalent series resistance when 1000 hours passed and 2000 hours passed from the start of measurement was also obtained.

  Table 1 shows the capacitance change rate ΔCap / Cap and the equivalent series resistance change amount ΔESR obtained as described above, as an average value for 1000 samples. Table 2 shows the value of the equivalent series resistance at room temperature as an average value for 1000 samples.

In Table 1, when the experimental results for the sample S1 are compared with the experimental results for the sample S2, the capacitance change rate ΔCap / Cap and the equivalent when the 1000 hours have elapsed and when the 2000 hours have elapsed. It can be seen that the change amount ΔESR of the series resistance is remarkably small.
This is because the portion of the electrolyte layer 13 that is not covered with the carbon layer 14 in the sample S1 is covered with the insulating portion 17 as shown in FIG. 2, so that the electrolyte layer 13 is shielded from the outside air. This is probably because the deterioration of the electrolyte layer 13 due to the influence of oxygen and oxygen was suppressed.

Also, in Table 2, when the experimental result for sample S1 is compared with the experimental result for sample S3, it can be seen that the equivalent series resistance is remarkably small.
This is because the insulating part 17 is not interposed between the carbon layer 14 and the electrolyte layer 13 in the sample S1, and therefore the insulating part 107 is interposed between the carbon layer 104 and the electrolyte layer 103. This is presumably because the contact area between the cathode layer 14 and the electrolyte layer 13 is increased as compared with S3.

  Therefore, this experiment confirmed that deterioration of the electrolyte layer 13 was suppressed without increasing the equivalent series resistance (ESR) in the solid electrolytic capacitor element (FIG. 2) according to one embodiment of the present invention. .

In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. In the above embodiment, the insulating portion 17 is formed of a resin such as an epoxy resin, but the present invention is not limited to this.
Further, the solid electrolytic capacitor element according to the present invention is not limited to the solid electrolytic capacitor shown in FIG. 3, and can be mounted on various solid electrolytic capacitors.

DESCRIPTION OF SYMBOLS 1 Solid electrolytic capacitor element 11 Anode body 12 Dielectric layer 12a, 12b Two divided area | region 13 Electrolyte layer 14 Carbon layer (cathode layer)
15 Silver paste layer (second cathode layer)
16 Sorting member 17 Insulating part

Claims (4)

  A dielectric layer is formed on the outer peripheral surface of the anode body, and a dividing member for dividing the outer peripheral surface of the dielectric layer into two regions is provided. In one of the two regions, the dielectric A solid electrolytic capacitor element in which an electrolyte layer and a cathode layer are formed in this order on a body layer, and an insulating portion is formed on both surfaces of the cathode layer and the sorting member.   The cathode layer and the sorting member are separated from each other, and a part of the insulating portion is interposed between the cathode layer and the sorting member so as to cover the surface of the electrolyte layer, The solid electrolytic capacitor element according to claim 1, wherein the insulating portion is not interposed between the electrolyte layer and the electrolyte layer.   The solid electrolytic capacitor element according to claim 1, wherein the insulating portion is made of resin.   A second cathode layer different from the cathode layer is formed on the cathode layer, and an outer peripheral surface of the cathode layer is covered with the insulating portion and the second cathode layer. Item 4. The solid electrolytic capacitor element according to Item 3.

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