JPS62234313A - Driving electrolyte for 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] [Industrial Application Field] The present invention relates to an electrolytic solution for driving an electrolytic capacitor,
By significantly lowering the specific resistance of the electrolyte, the loss angle tangent and high frequency characteristics of the electrolytic capacitor are improved.
Moreover, it provides an electrolytic capacitor that can suppress changes in capacitance and increase in leakage current, has a long life at high temperatures, and is highly reliable.

[Prior art and problems] Conventionally, so-called ethylene glycol/(11-acid ester)-based electrolytes have been used as electrolytes for driving aluminum electrolytic capacitors, especially for medium and high voltages. When the liquid is heated, the esterification reaction between ethylene glycol and boric acid progresses, and the water produced at this time reacts with the aluminum foil that is the material of the capacitor element in the electrolytic capacitor, causing stiffness. Electrolytic capacitors using this electrolyte could not be used at higher temperatures because the electrolyte dissolved and generated hydrogen gas, raising the internal pressure of the capacitor. In order to solve this problem, an electrolytic solution of the same type that promotes esterification and removes the produced water has been proposed, but although the reaction with water is suppressed, the viscosity of the electrolytic solution increases and the specific resistance becomes uneven. In electrolytic capacitors using this electrolyte, the loss angle tangent and impedance at high frequencies increase unnecessarily, making it impossible to meet requirement C of high characteristics.For these reasons, high temperature Ethylene glycol and boric acid ester-based electrolytes are not used in electrolytic capacitors for commercial use, but organic acid-based electrolytes with relatively large molecular weight iflU acids or their salts as solutes are used and studied. has been done.

The organic acid for medium and high pressures, the solute of the V-electrolyte, is a di-salt 1^ acid with a total carbon number of 16 to 22 and a side chain of 4i-'f. Driving electrolyte J) is well known, but in electrolytic capacitors using an electrolyte containing a dibasic acid, the solute itself reacts with the aluminum foil representing the capacitor element to form a complex. In high-temperature load tests and high-temperature no-load tests, an extreme decrease in electrostatic capacitance and a significant increase in leakage current were observed, creating a demand for electrolytic capacitors with higher performance. It was impossible to respond to this.

[Improvements and Summary of the Invention] However, the present invention can eliminate the drawbacks mentioned in 1-1. Specifically, by using 1.10-decanedicarboxylic acid or a salt thereof, By preventing the formation of complexes between monobasic acids and aluminum foil, changes in the electrostatic field q of electrolytic capacitors and increases in leakage current can be suppressed, and by using 1°6-decanedicarboxylic acid or its salt, the ratio of electrolyte solution can be reduced. By lowering the resistance and reducing the tangent of loss angle and impedance at high frequencies, we can provide electrolytic capacitors with higher performance and reliability.

[Example] Next, specific examples of monobasic acids having a total number of carbon atoms of 12 to 34 and having a vinyl group or a carboxyl group in the side chain will be shown.

In the present invention, the solvent used is one or more of polyhydric alcohols such as ethylene glycol.

Example of an electrolytic solution according to the present invention in which a mixture of the dibasic acid or its salt listed in L, 1.10-decanedicarboxylic acid or its salt, and 1゜6-decanedicarboxylic acid or its salt is dissolved in a solvent. are shown in Table i1 along with a conventional example. The electrolytic solution composition is wt%, and the specific resistance (Ω·cm) is at a solution temperature of 20°C. Further, the spark voltage was at 85°C.

Table 4 Examples of Ship Songs with ClausesNext, among the electrolytes shown in Table 1, conventional examples 2) Examples! and an electrolytic capacitor using the electrolyte of Example 9 (
Table 2 shows the results of a high temperature load test of 20 pieces each with a constant fi of 400 V-10 μF at a temperature of 105° C. and a rated voltage applied for 1000 hours. In addition, electrolytic capacitors (rated 40
High temperature no-load test (105
℃.

1000 hours) are shown in Table 3. (Each value of the characteristic during the ?7J period and after the test is the average value of each 20 electrolytic capacitors.) [Effect of the invention] As can be seen from Table 2 and the third person, in Conventional Example 2, the initial 116 capacitance is about 10% lower than the rated value, and even after testing, the rate of change is large. Furthermore, as can be seen from Table 3, the leakage current in Conventional Example 2 is approximately 60 times greater.

As described above, the phenomenon in the conventional example summarized by Table 2 and 3jI2 is caused by the dibasic acid, which is a 1-solute in the driving electrolyte, reacting with the aluminum foil forming the capacitor element. In order to reduce the surface area by an Reacts to form an unstable aluminum complex, which is I″F:
The leakage current increases because the metal dissolves in the electrolytic solution at 1 temperature.

- On the other hand, the present invention furthermore suppresses the acid complex formation of this dichloride acid by using 1.1O--L' candicarboxylic acid and 1,6-decanedicarboxylic acid or salts thereof. This makes it possible to prevent IL from occurring. In addition, by lowering the specific resistance, the tangent of the loss angle and the impedance at high frequencies can be kept low.

Next, we will discuss the effect on product properties caused by suppressing complex formation by adding 1.10-decanedicarboxylic acid or its salt, for example, when compound 1 was added at 5 wt.
The rated electrostatic field is as follows:
Taking as an example the change in the initial capacitance ratio for TrJ1
Figure 2 shows the change in leakage current value in a high temperature no-load test at 105°C for 1000 hours. The electrolytic capacitors used here are all rated at 400V-LO.
μF, and the valley value is the average value of 20 γ values.

In addition, regarding the effect on product characteristics caused by the addition of 1.6-decanedicarboxylic acid or its salt, for example, 1.6-decanedicarboxylic acid ammonium salt was added to an electrolytic solution containing 5 wt% of compound l. FIG. 3 shows an example of the change in impedance (100KH7) in this case. The 'It solution capacitor used here has a rating of 400
■・220μF, the average value of 20 explants.

As can be seen from FIG. 1, when the concentration of 1.10-decanedicarboxylic acid ammonium salt added is low, the initial capacitance ratio is low. Addition of 0.5wt% has little effect, but 1w
Addition of t% produces a sufficient effect. Therefore, 1wt%
The above addition is preferable. As can be seen from Figure 72, 1.
When the addition concentration of to-decanedicarboxylic acid ammonium salt is low, the leakage current value is large, 0.5 wt%, 1 wt%
decreases with the addition of The effect is small when added at 0.5 wt%, but the effect becomes sufficiently clear when added at 1 wt%. As can be seen from FIG. 3, when the concentration of 1,6-decanedicarboxylic acid ammonium salt added is low, the impedance is high, and by increasing the added rit, the impedance becomes low and the effect becomes sufficiently clear.

Therefore, by using the driving electrolyte according to the present invention, it is possible to provide an electrolytic capacitor with higher performance and higher reliability.

[Scope of Practical Application of the Invention] Among the components of the electrolytic solution according to the present invention, 1. The amount of 10-decanedicarboxylic acid or its salt mixed is preferably 1 wt% or more, and if it is less than 1 wt%, the product characteristics will deteriorate significantly, and the amount of 1,6-decanedicarboxylic acid or its salt mixed is 1 wt% to 10 wt%. A range of % is preferred. but,
1. Mixing of 6-decanedicarboxylic acid [Since the spark voltage of the electrolyte decreases as the amount increases, it cannot be put into practical use at a concentration of 10 wt% or more. For example, FIG. 4 shows changes in concentration and spark voltage when 1,6-decanedicarboxylic acid ammonium salt is added to an electrolytic solution containing 5 wt % of Compound 1.

[Brief explanation of drawings]

Figure 1 is a characteristic diagram showing the relationship between the concentration of 1°10-decanedicarboxylic acid ammonium salt added to Compound 1 shown in Table 1 and the ratio between the initial electrostatic capacitance and the rated capacitance of an electrolytic capacitor. Figure 2 is a characteristic diagram showing the relationship between the concentration of 1,6-decanedicarboxylic acid ammonium salt added to compound 1 and the leakage current of an electrolytic capacitor, and Figure 3 is a characteristic diagram showing the relationship between the added concentration of 1,6-decanedicarboxylic acid ammonium salt to compound 1 and the leakage current of the electrolytic capacitor. FIG. 4 is a characteristic diagram showing the relationship between the concentration of 1,6-decanedicarboxylic acid ammonium salt added to Compound 1 and the spark voltage of the electrolytic solution.

Claims (2)

[Claims] (1) One or more dibasic acids having a total carbon number of 12 to 34 and having a vinyl group or a carboxyl group in the side chain or a salt thereof, 1.10-decanedicarboxylic acid or a salt thereof, and 1.6 An electrolytic solution for driving an electrolytic capacitor, comprising a solute consisting of decanedicarboxylic acid or a salt thereof, and an organic polar solvent. (2) The electrolytic solution for driving an electrolytic capacitor according to claim (1), wherein the organic polar solvent is composed of one or more types of polyhydric alcohols.