JPH06349685A - Manufacture of organic semiconductor solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To manufacture a solid electrolytic capacitor having a rated voltage of 25V by using a complex TCNQ salt. CONSTITUTION:The title method contains the process for dipping a wound type capacitor element composed of anode foil, cathode foil, and separator paper in an aqueous solution containing at least phosphoric acid ions and sodium ions, the process for volatilizing water remaining in the capacitor element, and the process for impregnating the capacitor element with a complex TCNQ salt.

Description

Detailed Description of the Invention

[0001]

The present invention relates to TCN as a solid electrolyte.
The present invention relates to a method for manufacturing an organic semiconductor solid electrolytic capacitor using a Q complex salt.

[0002]

2. Description of the Related Art An example of an organic semiconductor solid electrolytic capacitor using a TCNQ complex salt as an electrolyte is disclosed in Japanese Patent Publication No. 3-765.
No. 73. Here, TCNQ is 7,7,
It is an abbreviation for 8,8-tetracyanoquinodimethane.

TC with isoquinoline in which the N-position is substituted with an alkyl group, as disclosed in the above Japanese Patent Publication No. 3-76573.
Solid electrolytic capacitors using NQ complex salts have excellent high frequency characteristics and are used for switching power supplies and the like.

[0004]

[Problems to be Solved by the Invention] However, TCN
The solid electrolytic capacitor using the Q complex salt has a higher electric conductivity than a so-called aluminum dry electrolytic capacitor using a liquid electrolyte.
There is a problem that the repairability of the oxide film of the valve metal provided by anodic oxidation and anodization is weak, and short-circuit defects frequently occur when a high temperature load test is performed by applying a voltage exceeding 25V.

That is, it was considered impossible to commercialize a solid electrolytic capacitor using a TCNQ complex salt with a rated voltage exceeding 25V.

On the other hand, the present invention intends to commercialize a solid electrolytic capacitor using a TCNQ complex salt by improving the manufacturing method thereof, even if the rated voltage exceeds 25V.

[0007]

A method of manufacturing an organic semiconductor solid electrolytic capacitor according to the present invention comprises a winding type capacitor element composed of an anode foil, a cathode foil and a separator paper.
A step of immersing in an aqueous solution containing at least phosphate ions and sodium ions; a step of volatilizing water remaining in the capacitor element;
And a step of impregnating with an NQ complex salt.

[0008]

According to the manufacturing method of the present invention, the dielectric oxide film in the capacitor element is modified by the interaction between the phosphate ion and the sodium ion, the recoverability of the oxide film against the TCNQ complex salt is improved, and the capacitor is completed. The withstand voltage characteristics of the product are improved.

[0009]

EXAMPLES Examples of the present invention will be described below in accordance with the history of experiments leading to the present invention.

First, a separator paper is sandwiched between an aluminum anode foil and an opposing cathode foil and wound in a cylindrical shape to form a capacitor element.

Next, the anode foil of this capacitor element is subjected to chemical conversion treatment and separator paper is subjected to carbonization treatment.

Next, this capacitor element is dipped in various aqueous solutions as shown in Table 1 for 10 minutes (comparative example 2 is not dipped).

[0013]

[Table 1]

Next, the capacitor element is dried at 85 ° C. to volatilize residual water.

Next, a TCNQ complex salt having excellent pressure resistance (N, N, which was described by the present inventors in Japanese Patent Application No. 5-50674),
N'-1,8-n-octyl-3,5-lutidine ₂ -TCN
Q ₄₎ were placed in an aluminum case with a diameter of 4mm, the TCNQ
The complex salt is heated on a hot plate at 300 ° C. to be melted, and the preheated capacitor element is immersed in the liquid TCNQ complex salt, and then rapidly cooled, whereby the TC is added to the capacitor element.
Impregnate with NQ complex salt.

Finally, the opening of the aluminum case is sealed with an epoxy resin, and a rated voltage (DC35V) is applied at about 125 ° C. for 1 hour to perform aging to obtain a solid electrolytic capacitor.

With respect to each sample of the solid electrolytic capacitor thus obtained, the initial characteristics were measured, and then a high temperature load test was conducted to examine the occurrence status of short circuit failure. The results are shown in Table 2. Here, the high temperature load test is 105 ° C.
1 while heating to and applying the rated voltage (DC35V)
It is to leave it for 000 hours.

[0018]

[Table 2]

In Table 2, C (electrostatic capacity) and tan
δ (tangent of loss angle) was measured at 120 Hz, ESR (equivalent series resistance) was measured at 100 kHz, and LC (leakage current) was measured 30 seconds after the rated voltage was applied. Is. In addition, each measured value is an average value for non-defective products out of 100 samples each,
Regarding LC quality, 1 μA or less was regarded as a good product, and a high temperature load test was performed only on the LC good sample.

As can be seen from Table 2, in Examples 1 to 6 which were immersed in an aqueous solution containing both phosphate ions and sodium ions, the immersion treatment in an aqueous solution containing phosphate ions and ammonium ions was performed. Compared to Comparative Example 1 in which the dipping treatment was performed and Comparative Example 2 in which such a dipping treatment was not performed, the LC yield in the initial characteristics was high, and no short circuit failure occurred in the high temperature load test.

Thus, in the process of manufacturing an organic semiconductor solid electrolytic capacitor, if the capacitor element is immersed in an aqueous solution containing at least phosphate ions and sodium ions, the withstand voltage of the capacitor is improved. Has been derived.

Incidentally, comparing 1 to 4 of the above embodiments,
When the concentration of the aqueous solution containing phosphate ion and sodium ion increases, C decreases, tan δ increases, ESR increases.
There is a tendency for the characteristics to deteriorate, that is, it is not preferable to make the concentration too high.

[0023]

According to the present invention, it is possible to obtain a solid electrolytic capacitor having a high withstand voltage which is excellent in high frequency characteristics and leakage current characteristics and which does not cause a short circuit failure in a high temperature load test.

Claims (4)

[Claims] 1. A step of immersing a wound-type capacitor element composed of an anode foil, a cathode foil, and separator paper in an aqueous solution containing at least phosphate ions and sodium ions, and remaining in the capacitor element. And a step of impregnating the capacitor element with a TCNQ complex salt, the method for producing an organic semiconductor solid electrolytic capacitor. 2. The method for producing an organic semiconductor solid electrolytic capacitor according to claim 1, wherein the aqueous solution containing at least phosphate ions and sodium ions is an aqueous solution of sodium dihydrogen phosphate. 3. The method for producing an organic semiconductor solid electrolytic capacitor according to claim 1, wherein the aqueous solution containing at least phosphate ions and sodium ions is an aqueous solution of disodium monohydrogen phosphate. 4. The method for producing an organic semiconductor solid electrolytic capacitor according to claim 1, wherein the aqueous solution containing at least phosphate ion and sodium ion is an aqueous solution of trisodium phosphate.