JP4707208B2 - Winding type electrolytic capacitor - Google Patents

Description

【００２０】
表１に示されているように、実施例及び比較例の各コンデンサについて初期の静電容量と１００ｋＨｚにおける等価直列抵抗を測定した後、はんだ耐熱試験を行った。この試験は、試料コンデンサを２４０℃で１０秒間加熱する操作を２回反覆して行うものであり、試験後に再び１００ｋＨｚにおける等価直列抵抗を測定すると共に、外観を調べた。これらにより、実施例の試料コンデンサは比較例の試料コンデンサに較べて初期の静電容量が大きく、高周波における等価直列抵抗が小さく、はんだ耐熱試験による等価直列抵抗特性の劣化が少なく、外観にも変化がないことが確認できた。
【００２１】
次に、実施例１に準ずる方法で、セパレータ中のアクリル繊維とポバール繊維の比率を表２に示すように変化させたコンデンサを実施例３、４及び比較例４として製作し、その初期特性を測定した。
【００２２】
【表２】

【００２３】
表２に基づき、アクリル繊維含有量と等価直列抵抗の初期値との関係を図１に示し、ポバール繊維含有量と静電容量の初期値との関係を図２に示す。これらの図面から明らかなように、アクリル繊維の含有量は５０％以上が好ましく、ポバール繊維の含有量は５〜５０％の範囲が好ましいことが判明した。
【００２４】
【発明の効果】
以上のように、本発明による巻回型電解コンデンサは、セパレータの強度、巻回性及び電解質の保持性が優れ、高周波での等価直列抵抗が低く、耐熱温度が高いために特に面実装に用いた場合に他の電子部品と同等の温度ではんだ付けが可能になる等の長所を有している。
【図面の簡単な説明】
【図１】 本発明におけるセパレータのアクリル繊維含有量と製品の高周波等価直列抵抗との関係を示す線図
【図２】 本発明におけるセパレータのポバール繊維含有量と製品の静電容量との関係を示す線図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a separator for a wound electrolytic capacitor, and more particularly to a separator suitable for holding an electrolyte made of a conductive polymer compound.
[0002]
[Prior art]
Conventionally, an electrolytic capacitor is provided with an anode foil having a roughened surface of a valve metal foil such as tantalum or aluminum and an anodized layer formed thereon, and a cathode foil made of a valve metal foil having a roughened surface. Capacitor elements wound with electrolytic paper sandwiched between them, carboxylic acids such as adipic acid, maleic acid, and phthalic acid as electrolytes, solutes such as nitro compounds and phosphoric acid compounds, water, ethylene glycol, γ-butyrolactone, etc. There are those impregnated with a driving electrolyte dissolved in the above solvent.
[0003]
However, the electrolytic capacitor using the driving electrolyte as the electrolyte as described above cannot sufficiently reduce the equivalent series resistance at a high frequency. In recent years, electronic devices are required to operate at higher speed and save power, and for that purpose, it is required to lower the equivalent series resistance. However, the electrolytic capacitors using the above-described driving electrolyte correspond to this. It was difficult. Therefore, in recent years, electrolytic capacitors using manganese dioxide or TCNQ complex as an electrolyte have been developed.
[0004]
In the case of an electrolytic capacitor using manganese dioxide as an electrolyte, a heat treatment step is required in which manganese nitrate is impregnated and then heated to 300 to 400 ° C. to change to manganese dioxide. Carbonized, the shape of the capacitor element was liable to collapse, and the lead terminals were discolored.
[0005]
An electrolytic capacitor using a TCNQ complex as an electrolyte is difficult to control heat because remelting and thermal decomposition of the TCNQ complex occurs at high temperatures, and the molten solder temperature during surface mounting must be lower than that of other components. There wasn't.
[0006]
[Problems to be solved by the invention]
In order to improve the above-described drawbacks of the electrolytes of conventional electrolytic capacitors, electrolytic capacitors using functional polymer materials such as pyrrole, aniline, and thiophene as electrolytes have been developed in recent years. Compared to conventional electrolytic capacitors using manganese dioxide or TCNQ complex, electrolytic capacitors using functional polymer materials can reduce the equivalent series resistance, and heat treatment at 300 ° C or higher in the electrolyte impregnation process. There is no need to carry out, and the heat resistance is as high as 260 to 300 ° C.
[0007]
However, when ordinary electrolytic paper is used as a capacitor element separator, cellulose fibers such as manila hemp fibers in the electrolytic paper inhibit the polymerization reaction of the functional polymer material, and it is difficult for the electrolyte to penetrate into the capacitor element. Therefore, it takes a long time for impregnation. When the capacitor element is heat-treated to suppress the influence of such cellulose fibers and the electrolytic paper is carbonized, the impregnation property is improved, but the shape of the capacitor element is liable to collapse.
[0008]
In addition, it has been proposed to use a separator mixed with glass fiber instead of Manila hemp fiber and impregnate the above functional polymer material as an electrolyte. However, the thickness of glass fiber mixed paper cannot be reduced. In addition, there is a drawback that it is difficult to wind.
[0009]
Japanese Patent Application Laid-Open No. 10-340829 discloses that vinylon fibers are used as separators for electrolytic capacitors, and that this is impregnated with a functional polymer material as an electrolyte, which is added when paper is made from vinylon fibers. If the binder is not removed after being wound around the capacitor element, sufficient electrical properties cannot be obtained due to insufficient retention of the electrolyte, and the product has insufficient heat resistance and must be soldered when used for surface mounting. There was a drawback that the product expanded at the temperature of.
[0010]
Therefore, the present invention solves various problems associated with the use of cellulose fiber, glass fiber, or vinylon fiber in the separator when the above-described functional polymer material is used as an electrolyte, and the functional polymer material has It is intended to make full use of its advantages.
[0011]
[Means for Solving the Problems]
The present invention relates to a wound electrolytic capacitor that uses at least one of polypyrrole, polyaniline, polythiophene, or derivatives thereof as an electrolyte, and 50% or more acrylic fiber as a separator interposed between an anode foil and a cathode foil It is characterized by using the nonwoven fabric-like sheet | seat containing.
[0012]
Synthetic fibers other than acrylic fibers can be mixed with the non-woven sheet, but the synthetic fibers need to withstand the soldering temperature of 240 ° C. Preferred synthetic fibers that meet this requirement include polyester fibers, 6-6 nylon fibers, polyfluoroethylene fibers, and the like.
[0013]
Although the binder a heat-resistant synthetic fibers, including the aforementioned acrylic fiber for coupling to the non-woven fabric is added, most preferably the binder is a PVA (polyvinyl alcohol), to use a fiber-like. The amount of poval fiber added to the separator is desirably 5 to 50%.
[0014]
The polypyrrole derivative has a pyrrole skeleton, and has at least one of a hydroxyl group, an acetyl group, a carboxyl group, an alkyl group and an alkoxy group as a substituent at the 3-position, 3-position and 4-position or N-position. Things can be mentioned.
[0015]
Examples of the polyaniline derivative include those having an aniline skeleton and having at least one of an alkyl group, a phenyl group, an alkoxy group, an ester group, and a thioether group as a substituent.
[0016]
Further, the polythiophene derivative has a thiophene skeleton, and at its 3-position, 3-position and 4-position or S-position, at least one of a hydroxyl group, an acetyl group, a carboxyl group, an alkyl group, and an alkoxy group is used as a substituent. And polythiophene derivatives having poly 3,4-alkylenedioxythiophene.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
It added other heat-resistant synthetic fiber needed to acrylic fibers, and paper by adding textiles of PVA as a binder, to obtain a nonwoven sheet by heating and drying. During this time, textiles of PVA is in the first half of the drying process you adhere to acrylic fibers is softened in hot water, the second half of the drying process loses moisture solidify adhered to acrylic fibers rich in heat-resistant nonwovens Sheet. This sheet is heat resistant to withstand the soldering temperature.
[0018]
The 40 μm-thick sheet produced as described above is cut into a size of 2.7 mm × 75 mm, wound between an anode foil and a cathode foil of 2.2 mm × 75 mm, and wound with a diameter of about 6 mm. I got a thing. Since no oxide film was formed on the cut end face of the anode foil, this wound product was subjected to chemical conversion treatment in an aqueous solution of ammonium adipate at 60 ° C. and 10 wt%. Next, after immersing in a solution of 3,4-ethylenedioxythiophene and iron (III) p-toluenesulfonate dissolved in i-propanol (monomer to oxidizer molar ratio 1: 1.5), the mixture was heated to 100 ° C. Holding for 60 minutes, a solid electrolyte layer of polyethylene dioxythiophene (PEDT) was formed by chemical polymerization. The capacitor element thus obtained was put in a case, the opening was sealed with a sealing member, and a synthetic resin seating plate for surface mounting was attached to the sealing member, and Examples 1 and 2 and Comparative Examples 1 to 3 were used. 100 surface mount type solid electrolytic capacitors each having a rated voltage of 4 V and a rated capacitance of 100 μF shown in Table 1 were manufactured.
[0019]
[Table 1]

[0020]
As shown in Table 1, after measuring the initial capacitance and the equivalent series resistance at 100 kHz for each of the capacitors of Examples and Comparative Examples, a solder heat resistance test was performed. In this test, the operation of heating the sample capacitor at 240 ° C. for 10 seconds was repeated twice. After the test, the equivalent series resistance at 100 kHz was measured again and the appearance was examined. As a result, the sample capacitor of the example has a larger initial capacitance than the sample capacitor of the comparative example, the equivalent series resistance at high frequencies is small, the deterioration of the equivalent series resistance characteristics due to the solder heat resistance test is small, and the appearance also changes. It was confirmed that there was no.
[0021]
Next, capacitors in which the ratio of acrylic fiber to poval fiber in the separator was changed as shown in Table 2 by the method according to Example 1 were produced as Examples 3 and 4 and Comparative Example 4, and the initial characteristics were It was measured.
[0022]
[Table 2]

[0023]
Based on Table 2, the relationship between the acrylic fiber content and the initial value of the equivalent series resistance is shown in FIG. 1, and the relationship between the Poval fiber content and the initial value of the capacitance is shown in FIG. As is clear from these drawings, it has been found that the acrylic fiber content is preferably 50% or more, and the poval fiber content is preferably in the range of 5 to 50%.
[0024]
【The invention's effect】
As described above, the wound electrolytic capacitor according to the present invention is particularly suitable for surface mounting because it has excellent separator strength, winding property and electrolyte retention, low equivalent series resistance at high frequencies, and high heat resistance. In this case, soldering can be performed at the same temperature as other electronic components.
[Brief description of the drawings]
FIG. 1 is a diagram showing the relationship between the acrylic fiber content of a separator according to the present invention and the high-frequency equivalent series resistance of a product. FIG. 2 shows the relationship between the poval fiber content of a separator according to the present invention and the capacitance of a product. FIG.

Claims (3)

An anode foil and a cathode foil having an anodized film formed on the surface are wound with a non-woven separator interposed between them, and the separator is composed of at least one of polypyrrole, polyaniline, polythiophene, or a derivative thereof. A wound electrolytic capacitor characterized by holding a polymer compound, wherein the separator contains 50% or more acrylic fiber and 5 to 50% poval fiber as a binder in a mixed state .   2. The wound electrolytic capacitor according to claim 1, wherein the acrylic fiber has a cross-sectional diameter of 0.1 to 30.0 [mu] m.   The wound electrolytic capacitor according to claim 1, wherein the acrylic fiber has a fiber length of 0.5 to 15.0 mm.

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