JPH03161917A - Electrolyte for driving electrolytic capacitor - Google Patents

Abstract

PURPOSE:To form a high-performance and highly reliable electrolytic capacitor by a method wherein a dibasic acid, which has 12 to 22 of total carbon atoms and has a vinyl group in side chain, or its salt is used for the solute of an electrolyte and polyvinyl alcohol is added. CONSTITUTION:One kind or two kinds or more of dibasic acids, which have 12 to 22 of total carbon atoms and have a vinyl group in side chain, is/are used for the main solute of an electrolyte and at the same time, polyvinyl alcohol is added. Moreover, the specific resistance of the electrolyte is reduced, the tangent of loss angle and an equivalent series resistance are made small and a sparking voltage is made to rise. It is desirable that the amount of the solute of the dibasic acid is set in an extent of 5 to 30wt.%. When the amount is less than 5wt.%, the specific resistance is increased and when the amount exceeds 30wt.%, the sparking voltage of the electrolyte is reduced and such amount can not be put to practical use. It is desirable that an addition amount of the polyvinyl alcohol is set in an extent of 0.1 to 20%. In such a way, a high-performance and highly reliable electrolytic capacitor can be formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrolytic solution for driving an electrolytic capacitor,
By increasing the spark voltage of the electrolyte, it can be applied to higher voltage electrolytic capacitors and provides an electrolytic capacitor that is highly reliable under high temperatures.

[Prior Art and Problem 1] Conventionally, a so-called ethylene glycol/boric acid ester electrolyte has been used as an electrolyte for driving an aluminum electrolytic capacitor, particularly for high voltage.

When this type of electrolytic solution is heated, the esterification reaction between ethylene glycol and boric acid progresses, and water is produced at this time, and this water reacts with the aluminum foil that is the material of the condenser element in the electrolytic condenser. In order to dissolve this and generate hydrogen gas to increase the internal pressure of the condenser,
Electrolytic capacitors using this electrolyte could not be used for higher vorticity purposes. In addition, in order to solve the above-mentioned 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. , the specific resistance increases significantly, and in electrolytic capacitors using this electrolyte, the loss angle tangent and impedance at high frequencies increase significantly,
It was not possible to meet the demands for high characteristics. For this reason, electrolytic capacitors for high temperatures do not use ethylene glycol/boric acid ester electrolytes, but instead use organic acid electrolytes that contain relatively large molecular weight organic acids or their salts as solutes. However, it has not yet been possible to increase the spark voltage, and it has not been possible to apply this method to high-voltage electrolytic capacitors with a rated voltage of 450 V or higher.

[Improvements and Summary of the Invention] However, the present invention uses one type of dibasic acid having a total carbon number of 12 to 22 and a vinyl group in the side chain or 2f! as the main solute of the electrolyte. By using the above and adding ponovinyl alcohol, the drawbacks mentioned in L can be removed, and the specific resistance of the electrolyte can be lowered to reduce the tangent of the loss angle and the equivalent series resistance45. By increasing the spark voltage, a high-performance and highly reliable electrolytic capacitor is provided.

The structural formula of a dibasic acid having a total carbon number of 12 to 22 and a vinyl group in the side chain is as follows.

? OOC-(CI■)5・CH(CH2).・COOI
+ ---→Hymonium compound lCH=CH2 ? H=CI1■? 0 0 C・FCI12170H (cH2) , ■
・C 0 0 H ■ Compound 3C H = C H2 1100CiC11 ■ +2CI・CH2-CH=CHi
CH212cOOH - Compound 4 C H = C H2 These compounds (1) to (4) may be used alone or in combination.

[Example] Examples of the electrolytic solution according to the present invention are shown in Table 1 together with conventional examples. Electrolyte composition is wt%, conductivity (mS/t:
u+) LJ. ? iW IAa 4D” (:
Later, the spark electricity is at 85°C.

Table J Example of Electrolyte Composition Next, among the electrolytes shown in Table 1, electrolytic capacitors (rated at 450 V and using the electrolytes of Conventional Example 1 and Example 2)
220μFN (1) Temperature 105℃ for each 20 pieces
Table 2 shows the results of a high temperature load test in which the rated voltage was applied for 1,000 hours. In addition, electrolytic capacitors (rated 450■
High temperature no-load test (1
The results are shown in Table 3. Each initial and post-test characteristic is an average value of 20 electrolytic capacitors.

Table 2 Comparison of high temperature load characteristics (450V/220uF) Table 3 Comparison of high temperature no load characteristics (450V/220uF) [Effects of the invention] As can be seen from Tables 2 and 3, in Example 2, the initial The tangent of the loss angle is approximately 80% lower than that of Conventional Example 1, and the change is small even after the test. Further, as can be seen from Table 3, the i:i leakage current of Conventional Example 1 is more than 7 times higher.

In the present invention, the total number of carbon atoms is 12 to 22 and vinyl 7 is added to the side chain.
By using an acid or its salt as a solute and adding polyvinyl alcohol, the specific resistance can be lowered, the loss angle can be tangentially suppressed, and the spark voltage can be further reduced. By raising the temperature, it is possible to suppress an increase in leakage current after a high eddy no-load test.

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

[Scope of Practical Application of the Invention] Among the components of the electrolytic solution according to the present invention, there are 2. The amount of basic acid is preferably in the range of 5 to 30 wt%, and when it is 5 wt% unvortexed, the specific resistance increases, and conversely when it is 30 wt%
If the value exceeds this value, the spark voltage of the electrolyte decreases, making it impossible to put any of them into practical use. Further, the amount of polyvinyl alcohol added is preferably in the range of 0.1 to 20%; if it is less than 0.1 wt%, the effect of addition is small, and if it exceeds 20 wt%, the conductivity of the electrolyte decreases, so that neither can be put to practical use. No.

Furthermore, the average dispensing amount of polyvinyl alcohol is lOO ~
1000 is preferred.

Claims (1)

[Claims] (1) Electrolysis characterized in that the main solute is one or more dibasic acids or salts thereof having a total carbon number of 12 to 22 and a vinyl group in the side chain, and polyvinyl alcohol is added. Electrolyte for driving capacitors.