JPH0897097A - Solid electrolytic capacitor and production thereof - Google Patents

Abstract

PURPOSE: To obtain a solid electrolytic capacitor with excellent infrequency characteristics and temperature characteristics, able to withstand application of AC voltage by substantially equalizing the capacitance and breakdown voltage of a pair of electrode foils. CONSTITUTION: An aluminum etching foil is subjected to formation and cut into a pair of electrode foil which is then wound together with a separator paper to form a capacitor element. The capacitor element is immersed into a formation liquid and a voltage is applied to one or both electrode foil thus providing a formation film on the cut face of the electrode foil and a part where the electrode foil is caulked to a lead terminal. Subsequently, an aluminum case is appropriately filled with TCQN complex salt which is then fused to be liquefied and a preheated capacitor element is immersed into the liquefied TCQN complex salt. Since an aluminum etching foil subjected to formation is cut into a pair of electrode foils, the capacitance and breakdown voltage of the pair of electrode foil is substantially equalized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC capacitor connected in series with an AC signal transmission line in a speaker network or the like.

[0002]

2. Description of the Related Art As shown in FIG. 1, in a speaker network in which an AC signal 1 containing almost no DC component such as a voice signal is transmitted to a high frequency speaker 31 and a low frequency speaker 32 via an amplifier 2, Conventionally, a film capacitor or an electrolytic capacitor has often been used as the capacitor 4 connected in series to the signal transmission line on the high frequency speaker side.

A film capacitor is excellent in frequency characteristics such as impedance and equivalent series resistance, temperature characteristics, and the like, and in that respect, it is suitable for a speaker network.
If the electrostatic capacitance is about 10 μF or more, the external dimensions are large and the cost is high.

On the other hand, an electrolytic capacitor which has been put into practical use for a speaker network uses an electrolytic solution, and uses a pair of electrode foils formed at the same forming voltage. It is inferior to film capacitors in terms of frequency characteristics of impedance, equivalent series resistance, and temperature characteristics, and inferior in terms of life to film capacitors. Further, when an AC voltage is applied, the internal capacitor element vibrates, which adversely affects the sound quality.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a solid electrolytic capacitor having excellent frequency characteristics such as impedance and equivalent series resistance and temperature characteristics, which can withstand the application of AC voltage. It is a thing.

[0006]

A solid electrolytic capacitor according to the present invention is a solid electrolytic capacitor obtained by impregnating a pair of electrode foils having a dielectric coating wound together with separator paper on a capacitor element impregnated with an organic semiconductor as an electrolyte, The electrostatic capacity and the breakdown voltage of the pair of electrode foils are substantially equal to each other.

[0007]

In the above solid electrolytic capacitor of the present invention,
Since the electrostatic capacity and the withstand voltage of the pair of electrode foils are almost equal to each other, the voltage applied between both electrodes is divided into two equal parts regardless of the polarity, and the electrical stress and the thermal stress are Since it is not biased to one of the electrode foils, the excellent electric characteristics and life of the solid electrolytic capacitor will not be impaired even when an AC voltage is applied.

Further, in the above-described solid electrolytic capacitor of the present invention, since the capacitor element is fixed by the solid electrolyte, the capacitor element does not easily vibrate even when an AC voltage is applied.

[0009]

EXAMPLES The method for manufacturing the solid electrolytic capacitor according to the present invention will be described in showing the examples of the present invention.

First, an aluminum etching foil is subjected to a chemical conversion treatment at a chemical conversion voltage of about 90 V, and the foil is cut into an appropriate size to form a pair of electrode foils. The pair of electrode foils is a separator made of manila paper. It is wound with paper to form a capacitor element.

Next, the capacitor element is immersed in a chemical conversion liquid, and a voltage is applied to one electrode foil or both electrode foils,
A chemical conversion film is formed on the cut surface of the electrode foil and the caulking portion with the lead terminal.

Next, N-n butylisoquinolinium.T
An appropriate amount of TCNQ complex salt such as CNQ _{2 is} filled in an aluminum case, heated to about 300 ° C. to melt and liquefy, and the preheated capacitor element is immersed therein and immediately cooled.

Next, after the opening of the aluminum case is sealed with an epoxy resin, one of the electrode foils is regarded as an anode and an aging treatment of applying a specified DC voltage for about 1 hour. Give. In addition, in the case where the chemical conversion treatment is performed by applying a voltage to only one electrode foil when forming the cut surface and the crimped portion of the electrode foil, the aging treatment is performed with the electrode side to which the voltage is applied as the anode. Give.

Through the steps described above, the solid electrolytic capacitor according to the present invention is obtained. In the solid electrolytic capacitor according to the present invention, as can be seen from the manufacturing method, the aluminum etching foil that has been subjected to the chemical conversion treatment is cut into a pair of electrode foils. Are equal.

Here, in the above manufacturing method, when forming the cut surface and the caulking portion of the electrode foil, a voltage is applied to only one electrode foil to carry out the chemical conversion treatment, and a solid electrolytic capacitor having a rating of 25 V and 5 μF (Example 1) ) And the rated 25V, 5 μ, which was subjected to the process of inverting the polarity and applying the specified DC voltage for about 1 hour after the aging process in the first embodiment.
F solid electrolytic capacitor (Example 2) and formation voltage of about 9
An aluminum etching foil subjected to a chemical conversion treatment at 0 V was used as an anode, and an unformed aluminum etching foil was used as a cathode, and the subsequent steps were performed in accordance with the production method of Example 1, and the rated voltage was 25 V.
Table 1 shows the results obtained by measuring various characteristics of the 0 μF solid electrolytic capacitor (Comparative Example 1).

[0016]

[Table 1]

In Table 1, C is the capacitance measured at 120 Hz, tan δ is the tangent of the loss angle measured at 120 Hz, ESR is the equivalent series resistance measured at 100 kHz, L
C1 is a DC voltage of 25 V in the forward direction (the direction in which voltage was applied during aging in Example 1 and Comparative Example 1 and the direction in which voltage was initially applied during aging in Example 2) according to EIAJ-RC-2366. Leakage current measured 30 seconds after the application of LC, LC2 is the leakage current measured 30 seconds after the application of a DC voltage of 25 V in the opposite direction to the LC1 measurement, and the LC yield is the forward and reverse directions in 100 samples. Shows the number of non-defective products having a leakage current of 10 μA or less. In addition, C and ta in Example 1 and Example 2
The values of nδ, ESR, LC1 and LC2 are average values for 20 good LC products, and C and tan in Comparative Example 1
The values of δ, ESR, LC1, and LC2 are average values for 20 LC semi-defective products having a forward leakage current of 10 μA or less.

From Table 1, the effect of improving the LC yield according to the embodiment of the present invention can be read. Most of the LC defects in Comparative Example 1 are due to the defects in the reverse LC. Further, compared with Example 2 in which a voltage was applied in both directions for aging, Example 1 in which a voltage was applied in one direction for aging had a higher LC yield. It was first revealed by the experiment of the inventor of the present application.

Next, with respect to each of 20 good LCs in Examples 1 and 2 and 20 good LCs in Comparative Example 1, 50Vp-p, 60Hz, while applying a sinusoidal AC voltage without a DC component, Table 2 shows the results of a high temperature load test conducted at 85 ° C. for 1000 hours.

[0020]

[Table 2]

In Table 2, ΔC / C represents the rate of change of the capacitance C with respect to the value before the test. Meanings of other symbols, measurement conditions, etc. indicate the average value after the test for all the samples. The difference is the same as the case of Table 1.

As can be seen from Table 2, the change in various characteristics due to the high temperature load test while applying the AC voltage is relatively small in both Example 1 and Example 2. On the other hand, in Comparative Example 1, 8 of 20 samples suffered a short circuit failure within 150 hours, and ΔC / C was -50% or more for the remaining 12 samples. That is,
The solid electrolytic capacitor of the example of the present invention can sufficiently withstand AC even in terms of life, whereas the solid electrolytic capacitor of Comparative Example 1 cannot be used for AC.

[0023]

As described above, the solid electrolytic capacitor according to the present invention is suitable for a speaker network to which an AC voltage is applied.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a speaker network in which a solid electrolytic capacitor according to the present invention is used.

[Explanation of symbols]

 1 AC signal 2 Amplifier 31 High frequency speaker 32 Low frequency speaker 4 Capacitor

Claims (3)

[Claims] 1. A solid electrolytic capacitor in which a pair of electrode foils on which a dielectric film is formed is wound together with separator paper and an organic semiconductor is impregnated into a capacitor element, and the capacitance and pressure resistance of the pair of electrode foils. The solid electrolytic capacitors are characterized in that they are substantially equal to each other. 2. The solid electrolytic capacitor according to claim 1, wherein the solid electrolytic capacitor is connected in series to an AC signal transmission line. 3. A step of applying a chemical conversion treatment to a pair of electrode foils at the same formation voltage, a step of impregnating a capacitor element formed by winding the pair of electrode foils with a separator paper with an organic semiconductor as an electrolyte, and the pair of electrodes. And a step of applying an aging treatment while applying a DC voltage in one direction between the foils, the method for producing a solid electrolytic capacitor.