JPS63200516A - Electrolytic capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an electrolytic capacitor using a solid electrolyte made of an improved organic semiconductor. - (Prior Art) In general, a dry foil type electrolytic capacitor is constructed by connecting a pair of anode and cathode foils made of, for example, high-purity 1-quality aluminum to a pair of lead terminals -1-++ also made of aluminum. - A capacitor element is wound with a spacer interposed between cathode foils, impregnated with a driving electrolyte, housed in a case, and the opening of the case is sealed with an exterior covering such as a hook. However, since the driving electrolyte uses an organic carboxylic acid such as ammonium adipate in an organic solvent such as ethylene glycol, there is a limit to the improvement of tan δ characteristics, and the specific resistance increases at low temperatures. There were issues that needed to be resolved in order to meet market demands, such as extremely poor characteristics and lack of reliability for use over a wide temperature range.

Therefore, in recent years, various solutions using various TCNQ complexes instead of the driving electrolyte have been proposed, and some of them have been put into practical use.

There are generally two methods for impregnating a capacitor element wound with a TCNQ complex: solution impregnation method, dispersion impregnation method, and vacuum evaporation method. Various measures have been taken to achieve this goal.

In particular, as conditions for the solid electrolyte, it is important that the resistance value itself, which affects tan δ as a capacitor characteristic and the equivalent series resistance, is small, and that the specific resistance value is stable even under temperature, especially high temperature.

Therefore, as a means of impregnating the wound element with the TCNQ complex, it has been found that heat-melting and liquefaction treatment is effective for permeating the TCNQ complex into the inside of the element in the required amount, as previously proposed in patent publications or technical literature. It is said that

Among them, those disclosed in JP-A-61-7618, JP-A-61-47642, etc.
Conventional - A mixture of a lactone compound or a quinoline compound added to a TCNQ complex with an isoquinoline or pyridine electron donor and TCNQ as an electron acceptor, which has been formed into a film, is heated and melted and impregnated into a capacitor element. The organic semiconductor is assimilated to form a solid electrolyte layer made of an organic semiconductor. That is, a compound is added to the TCNQ complex, which does not have a melting point and decomposes and becomes insulating when heated, thereby making it possible to melt it by heating.

However, lactone compounds and quinoline compounds are considered to act as electron donors for TCNQ, which acts as an electron acceptor. In the TCNQ complex, the specific resistance varies greatly depending on the ratio of TCNQ, which is an electron donor and an electron acceptor.

For example, when the ratio of TCNQ as an electron donor to electron acceptor is generally 1:2, the resistivity is the lowest, but when the ratio is 1:1, the resistivity becomes large, ranging from tens of Ωcar to hundreds of 0 cm, and Considering that in the case of 1 to 3, the ratio becomes large, ranging from several K Q cm to several tens of 0 cm, mixing other compounds with the TCNQ complex will deteriorate the properties of the TCNQ complex itself.

On the other hand, Japanese Patent Application Laid-open No. 17609/1983,
Publication No. 8-191414 or JP-A-59-63604
What is disclosed in the publication is generally understood, that is, TCNQ complexes are divided into those that have melting points and those that do not, depending on the type of substance that serves as an electron donor, and even if the skeleton structure is the same. For example, a quinoline or isoquinoline with a methyl group as a substituent has no melting point and decomposes when heated and becomes insulating.
Propyl group, ethyl group.

Focusing on the fact that those substituted with butyl groups have a melting point, N-n-propyl (
or N-isoquinoline, N-ethylisoquinoline, Nn-butylisoquinoline, quinoline substituted with a hydrocarbon group at the N-position, isoquinoline, etc., using a TCNQ complex.

However, organic substances are generally sensitive to heat, and the above-mentioned TCNQ complex is also sensitive to heat, and according to the inventor's experimental results described below, there is a problem in that the resistivity value changes greatly when left at 105°C, for example. An electrolytic capacitor using a TCNQ complex had a problem in that various properties in a 105°C life test were significantly deteriorated.

(Problems to be Solved by the Invention) As described above, the electrolytic capacitor having the above structure is TCN
There were problems with the specific resistance characteristics of the Q complex itself, and there was also a problem of specific resistance deterioration at high temperatures.

The present invention has been made in view of the above points, and an object of the present invention is to provide an electrolytic capacitor using a TCNQ complex that has been developed based on various experimental results and is suitable for heat melt impregnation without deterioration of resistivity even at high temperatures. It is something to do.

[Structure of the Invention] (Means for Solving the Problems) The electrolytic capacitor of the present invention has a capacitor element wound with a spacer interposed between an anode foil and a cathode foil made of a valve metal, and heated and melted as a solid electrolyte. In the electrolytic capacitor impregnated with an organic semiconductor, the organic semiconductor is N.

It is characterized by using a TCNQ complex of N-methyl n-propylpiperidine.

(Function) According to the electrolytic capacitor having the above configuration, the organic semiconductor used as the electrolyte has little change in resistivity at high temperatures, so the high temperature life characteristics of the capacitor do not change much and reliability is improved.

(Examples) Examples of the present invention will be described in detail below. That is, as shown in FIG. 2, first, for example, the surface of the aluminum foil is roughened with an etching solution to increase the surface area, and then the anode foil 1 is formed with an anodic oxide film, and the surface of the aluminum foil is roughened with the same etching solution as described above to increase the surface area. A cathode foil 2 is prepared which is an enlarged version of . Next, a spacer 3 made of kraft paper or Manila paper is interposed between the anode foil 1 and the cathode foil 2, and an anode lead-out terminal 4 or a cathode lead-out terminal 5 is placed at an arbitrary point on the anode foil 1 and the cathode foil 2, respectively. is attached to obtain a wound capacitor element 6. Next, as shown in FIG. 3, a TCNQ complex of N,N-methyl npropylpiperidine is placed in a case 7 made of aluminum, etc.
, TCNQ complex of N-methyl n-propylpiperidine is heated and melted to form TCN of N,N-methyl n-propylpiperidine.
As shown in FIG.
stored in the CNQ complex melt 8, and the N.

A TCNQ complex melt 8 of N-methyl n-propyl piperidine is impregnated into the capacitor element 6, then cooled and solidified, and the opening of the case 7 is sealed with a sealing member 9.

In the electrolytic capacitor having the above configuration, the TCNQ complex of N,N-methyl n-propyl C veridine as an organic semiconductor used as an electrolyte is resistant to the CNQ complex itself at high temperatures, as is clear from the experimental results shown below. Since the change in resistivity is small, it can greatly contribute to stabilizing the characteristics of electrolytic capacitors when left at high temperatures.

Next, the TCNQ complex (a) of N,N-methyl n-propylpiperidine according to the present invention and the TCNQ complex (b) of N-butylisoquinoline, which is suitable for the heat-melting treatment described above as a conventional reference example. The results of measuring the change in resistivity at 105° C. in the following method were as shown in FIG. The measurement method is to place 5 g of each TCNQ forceps 0 complex in (a) and (b) into a mold with a diameter of 13mm, apply a pressure of 10 tons from above and below with a piston, apply silver paste on both sides of the molded body, and dry. The resistance measured between the electrodes was used as the initial value, and then the temperature was heated to 105°C.
The device is left in a constant temperature bath, and the resistance value is measured at regular intervals.

As is clear from FIG. 4, N according to the present invention.

TCNQ complex of N-methyl n-propylpiperidine (a)
is T of N-n-butylisoquinoline according to the conventional reference example.
It was demonstrated that the change in resistivity was smaller than that of CNQ complex (b).

Note that the other TCNQ complexes according to the conventional reference examples described above showed the same tendency as the one in (b) above, so their descriptions are omitted here.

-8= Next, an example of comparison of characteristics in a 105° C. high temperature load test of electrolytic capacitors using each of the above TCNQ complexes will be described.

Example A Anode foil The aluminum foil surface was roughened to increase the surface area, and an anodized film was then formed. Anode foil Cathode foil The aluminum foil surface was roughened and the surface area was expanded. Cathode foil spacer. Manila paper TCNQ with a thickness of 50 μm. Complex N, N-methyl n-propyl piperidine TCNQ complex TCNQ complex heating melting conditions case 250℃ for 10 seconds element preheating condition 270℃ impregnation condition 250℃ 30 seconds case sealing epoxy resin sealing or more Rating 25V-10μF Electrolytic capacitor.

Reference Example 8 TCNQ Complex An electrolytic capacitor with a rating of 25V-10μF having the same configuration as the above example except for the TCNQ complex of N-n-butylisoquinoline.

Therefore, the electrolytic capacitor A of the embodiment according to the present invention
and capacitance change rate (%) versus time of electrolytic capacitor of conventional reference example B in high temperature load test at 105°C, tan δ versus time and leakage current versus time (μA)
As a result of investigating each characteristic, the results are shown in FIGS. 5, 6, and 7.

As is clear from FIGS. 5 to 7, Example A is stable in all characteristics compared to the reference example, and the stability with respect to capacitance change rate and tan δ change is particularly remarkable. I understand that.

[Effects of the invention] According to the present invention, the beam is highly reliable when used at high temperatures;
An electrolytic capacitor with high practical value can be obtained.

[Brief explanation of the drawing]

1 to 3 relate to one embodiment of the present invention, in which FIG. 1 is a sectional view showing an electrolytic capacitor, FIG. 2 is an exploded perspective view showing a capacitor element constituting FIG. 1, and FIG. T on the case
An explanatory diagram of the manufacturing process with the CNQ complex added, Figure 4 is a time-resistivity characteristic curve, Figure 5 is a time-capacitance change rate characteristic curve, and Figure 6 is a time-tan δ characteristic curve. 7 are time-leakage current characteristic curve diagrams. 1... Anode foil 2... Cathode foil 6... Capacitor element 7... Case 8... TCNQ forcep body melt patent Applicant Lecon Electronics Co., Ltd. Time (h) Time (h) Figure 6 Time (h) Figure 5 Time (11) Figure 7

Claims (1)

[Claims] An electrolytic capacitor in which a capacitor element wound with a spacer interposed between an anode foil and a cathode foil made of a valve metal is impregnated with a heat-molten organic semiconductor as a solid electrolyte, wherein the organic semiconductor is N,N-methyl. An electrolytic capacitor characterized by using a TCNQ complex of n-propylpiperidine.