JPS62235720A - Solid 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 Field of the Invention This invention relates to an improved solid electrolytic capacitor.

BACKGROUND OF THE INVENTION In recent years, with the digitization of electrical equipment circuits, there has been an increasing demand for capacitors used in circuits that have low impedance in the high frequency range and are small and large in capacity.

Conventionally, plastic film capacitors, mica capacitors, and multilayer ceramic capacitors have been used as capacitors for high frequency ranges, but film capacitors and mica capacitors have larger shapes and can be shuffled, so larger capacitances have been used. However, laminated ceramic capacitors have the disadvantage that the smaller and larger the capacity, the worse the temperature characteristics and the higher the price. On the other hand, known high-capacity type capacitors include aluminum dry electrolytic capacitors and aluminum or tantalum solid electrolytic capacitors. These capacitors can achieve large capacitance because the anodic oxide film that serves as the dielectric can be made very thin, but on the other hand, the oxide film is easily damaged, so there is a risk of boar scratches between the oxide film and the cathode. It is necessary to provide electrolytes for repair. In aluminum dry electrolytic capacitors, etched positive and negative electrode aluminum foils are wound through a paper separator.
A separator is impregnated with liquid electrolyte. For this reason, capacitance decreases and loss (tan δ) increases over time due to electrolyte leakage, evaporation, etc. At the same time, high frequency characteristics and low temperature characteristics deteriorate significantly due to the ionic conductivity of the electrolyte. It has the following drawbacks. or,
In aluminum and tantalum solid electrolytic capacitors, manganese dioxide is used as the solid electrolyte in order to improve the drawbacks of the above-mentioned aluminum dry electrolytic capacitors.

This solid electrolyte is obtained by immersing an anode element in a manganese nitrate aqueous solution and thermally decomposing it at a temperature of around 350°C. In the case of this capacitor, since the electrolyte is solid, there are no drawbacks such as electrolyte leakage at high temperatures or performance degradation caused by solidification at low temperatures, and it has better frequency and temperature characteristics than capacitors using liquid electrolytes. However, due to damage to the oxide film due to thermal decomposition of manganese nitrate and the high resistivity of manganese dioxide, the impedance or loss in the high frequency range is 1% compared to multilayer ceramic capacitors and plastic film capacitors.
The value is more than an order of magnitude higher.

In order to solve the above problems, organic semiconductors (7, 7, 8
, 8-tetracyanoquinodimethane complex (hereinafter referred to as TCNQ complex) has been proposed. This organic semiconductor can be impregnated and coated on an oxide film by dissolving it in an organic solvent or melting it by heating.
Damage to the oxide film due to thermal decomposition that occurs during impregnation with nO2 can be prevented. TCNQCN has high conductivity,
It has excellent anodic oxidation properties, has good high-frequency characteristics, and can be used to produce large-capacity capacitors. For example, Mr. Shin Niwa has filed an application for an invention using an organic semiconductor consisting of N-n-propyl or N-1so-propyl inquinoline and TCNQ as a solid electrolyte (Japanese Patent Laid-Open No. 58-1
Publication No. 7609).

According to the invention, the TCNQ salt is impregnated into the wound aluminum electrolytic capacitor by heating and melting the TCNQ salt, thereby achieving a strong bond between the TCNQ salt and the oxide film, thereby increasing the high conductivity of the TCNQ salt. With the help of this contribution, aluminum capacitors with significantly improved frequency characteristics and temperature characteristics have been manufactured.

The use of such an organic semiconductor based on TCNQ salt as a solid electrolyte has already been disclosed in an invention filed by the same applicant (Japanese Patent Laid-Open No.
-1760C1 Publication), TCN
Since Q salt has higher conductivity and higher anodic oxidation ability (restoration effect) than manganese dioxide, it enables superior performance in both frequency characteristics and temperature characteristics compared to solid electrolytic capacitors using manganese dioxide.

In general, wound elements that are not impregnated with electrolyte use a separator such as manila paper between the anode and cathode. When using TCNQ salt as a solid electrolyte, according to Japanese Patent Application Laid-Open No. 58-123715, carbonizing the separator in advance is not sufficient in terms of high frequency characteristics and reliability at high temperatures. The present invention aims to solve the above-mentioned problems and aims to improve the high-frequency characteristics and high-temperature reliability of a capacitor with a simple structure.

Means for Solving the Problems The present invention has been made to achieve the above object, and its technical means include: a first electrode having an anodic coating; and a first electrode provided opposite to the first electrode. a second electrode, at least one insulating thread interposed between the first and second electrodes, and a space between the first and second electrodes impregnated with TCNQ salt and wound. The present invention provides a solid electrolytic capacitor characterized by:

Function: By using a thin insulating thread instead of something like manila paper as a separator for a wound element, the present invention can reduce the number of steps and reduce costs.
With a simple structure, tan δ can be improved at high frequencies of IKHz or higher, and the capacitance change (△C) when left at high temperatures can be improved.
was also improved. The thickness of the insulating thread of the present invention is desirably as fine as possible in order to improve the impregnating property of the electrolyte using capillary action. Further, it is sufficient to provide at least one insulating thread at the periphery or center, and it is possible to prevent the foil between the anode and the cathode from coming into contact with each other due to fraying.

Example Examples of the present invention will be described in detail below.

As a solid electrolyte, N-in-amyl isoquinolium (T
CNQ)2 was used. 16V, 100 as a wound element
A μF standard was used, and the impregnation was carried out by melt impregnation at 260°C, and the exterior was made of an aluminum can case and epoxy resin.

As winding elements, experiments were conducted using ordinary manila paper as a separator and carbonized one, and one in which two pieces of thread with a thickness of about 02 were interposed in the upper and lower peripheral parts instead of the separator. . A comparison of characteristics is shown below.

"Margin below - J As is clear from the table above, in this example, in which the thread was also used as a separator, there was little change in capacity after being left at high temperatures, and reliability was improved.

Effects of the Invention In short, the present invention uses insulating thread as a separator between the anode and cathode, which reduces costs by reducing the number of manufacturing steps, and improves the high frequency characteristics and reliability of capacitors with a simple configuration. was achieved.

Claims (1)

[Claims] a first electrode having an anodic film; a second electrode provided opposite to the first electrode; at least one insulating thread interposed between the first and second electrodes; A solid electrolytic capacitor characterized in that the space between first and second electrodes is impregnated with TCNQ salt and wound.