JP2005166889A - Electrolytic liquid for driving electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic liquid for suppressing the corrosion breakage line of a tab terminal and the tightening part of the inside of an electrolytic capacitor due to chlorine or the like leaked from the outside. <P>SOLUTION: Acipic acid, azelaic acid, sebacic acid, 1,6-decane dicarboxylic acid, carboxylic acid or its ammonium such as 7-vinyl hexadecene-1 and 16-carboxylic acid, a salt such as diethyl amine, and 0.1-5.0 wt% of alcoxy carbonyl dicarboxylic acid (formula 1, formula 2 and formula 3) are dissolved to a solvent mainly comprising ethylene glycol. A<SB>1</SB>, A<SB>2</SB>and A<SB>3</SB>: hydrocarbon groups of carbon numbers 1-18. A<SB>1</SB>, A<SB>2</SB>and A<SB>3</SB>may be same or different from each other. The reference characters a<SB>1</SB>and a<SB>2</SB>are hydrocarbon groups of hydrogen atoms or carbon numbers 1-18. OR<SB>1</SB>and OR<SB>2</SB>are alcoxyl groups. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an improvement in an electrolytic solution for driving an electrolytic capacitor (hereinafter referred to as an electrolytic solution), and more particularly, to an electrolytic solution that improves the corrosion prevention effect of a product.

The aluminum electrolytic capacitor was obtained by etching the surface of a high-purity aluminum foil, and winding the anode foil formed by anodizing aluminum oxide (dielectric film) and the etched cathode foil via a separator (electrolytic paper). The capacitor element is impregnated with an electrolytic solution, housed in an aluminum case, and sealed with a sealing body.
In the above electrolytic solution, carboxylic acid or its ammonium salt, boric acid or its ammonium salt, and polyhydric alcohols such as mannitol are dissolved in a solvent such as ethylene glycol.
Here, carboxylic acid, boric acid, and polyhydric alcohols form an ester compound, and the withstand voltage of the electrolytic solution is improved due to the structural characteristics thereof (see, for example, Patent Documents 1 to 3).
Japanese Examined Patent Publication No. 7-48459 (page 1-4) Japanese Patent Publication No. 7-48460 (page 1-3) Japanese Examined Patent Publication No. 7-63047 (page 1-4)

  However, when a voltage is applied to an aluminum electrolytic capacitor for a long time, the swaged portion between the tab terminal and the sealing plate ridge and the tab terminal is corroded by an electrochemical reaction due to chlorine entering from the outside. was there.

In response to the above problems, a method of preventing the reaction between the tab terminal and the invading substance from the outside, which is a cause of the corrosion disconnection, by applying a silicone or the like to the surface of the tab terminal and the caulking portion to insulate the surface. Has been proposed.
However, the above-described method has a problem in that there is a difference in the amount and position of silicone applied to each product, and the processing takes time.

  Due to the above-described problems, an efficient method that replaces the insulation treatment method for the surface of the tab terminal and the crimped portion has been demanded.

The present invention has been found as a result of various studies to solve the above-mentioned problems, and was found by dissolving alkoxycarbonyldicarboxylic acid in the electrolytic solution, and tab terminals inside the electrolytic capacitor and tabs and tab terminals of the sealing plate. It is intended to suppress the corrosion disconnection of the caulking portion of the steel.
That is, for driving an electrolytic capacitor, wherein a carboxylic acid or a salt thereof and an alkoxycarbonyldicarboxylic acid represented by the following chemical formulas (Chemical Formula 1 to Chemical Formula 3) are dissolved in a solvent mainly composed of ethylene glycol. Electrolytic solution.

Ａ_１、Ａ_２、Ａ_３：炭素数１〜１８の炭化水素基。
Ａ_１、Ａ_２、Ａ_３は同一または異なっていてもよい。
ａ_１、ａ_２:水素原子または炭素数１〜１８の炭化水素基。
ＯＲ_１、ＯＲ_２:アルコキシル基。
ＯＲ_１、ＯＲ_２は同一または異なっていてもよい。

A ₁ , A ₂ , A ₃ : a hydrocarbon group having 1 to 18 carbon atoms.
A ₁ , A ₂ , and A ₃ may be the same or different.
a ₁ , a ₂ : a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms.
OR ₁ , OR ₂ : an alkoxyl group.
OR ₁ and OR ₂ may be the same or different.

Ａ_１、Ａ_２：炭素数１〜１８の炭化水素基。
Ａ_１、Ａ_２、は同一または異なっていてもよい。
ａ_１、ａ_２：水素原子または炭素数１〜１８の炭化水素基。
ＯＲ_１、ＯＲ_２：アルコキシル基。
ＯＲ_１、ＯＲ_２は同一または異なっていてもよい。

_{A 1,} A _2: hydrocarbon group having 1 to 18 carbon atoms.
A ₁ and A ₂ may be the same or different.
a ₁ , a ₂ : a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms.
OR ₁ , OR ₂ : an alkoxyl group.
OR ₁ and OR ₂ may be the same or different.

Ａ_１、Ａ_２：炭素数１〜１８までの炭化水素基。
Ａ_１、Ａ_２、は同一または異なっていてもよい。
ａ_１：水素原子または炭素数１〜１８の炭化水素基。
ＯＲ_１：アルコキシル基。

_{A 1,} A _2: hydrocarbon group having up to 18 carbon atoms.
A ₁ and A ₂ may be the same or different.
a ₁ : a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms.
OR ₁ : an alkoxyl group.

Here, as C 1-18 hydrocarbon group of A ₁ , A ₂ , A ₃ or a ₁ , a ₂ , methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl Group, t-butyl group, n-pentyl group, isopentyl group, n-hexyl group, isohexyl group, n-heptyl group, isoheptyl group, n-octyl group, n-nonyl group, 2-ethylhexyl group, dodecyl group, tetradecyl group In addition to alkyl groups such as a group, hexadecyl group, octadecyl group, oleyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, etc., they may have a double bond or a triple bond.

Moreover, as an alkoxyl group of OR < ₁ >, OR < ₂ >, a methoxy group, an ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, t-butoxy group, pentyloxy group, n-hexyloxy group , Isohexyloxy group, n-octyloxy group, 2-ethylhexyloxy group, dodecyloxy group, tetradecyloxy group, hexadecyloxy group, octadecyloxy group, oleyloxy group and the like.

  And the dissolution amount of the said alkoxycarbonyl dicarboxylic acid (Chemical Formula 1-Chemical Formula 3) is 0.1-5.0 wt%, It is electrolyte solution for a drive of the electrolytic capacitor characterized by the above-mentioned.

  In addition, as the carboxylic acid dissolved as the main solute in the electrolyte solution, formic acid, acetic acid, adipic acid, lauric acid, stearic acid, decanoic acid, benzoic acid, salicylic acid, maleic acid, phthalic acid, fumaric acid, succinic acid, glutar Acid, azelaic acid, sebacic acid, 2-methyl azelaic acid, 3-tert-butyladipic acid, 1,6-decanedicarboxylic acid, 5,6-decanedicarboxylic acid, 7-vinylhexadecene-1,16-dicarboxylic acid, etc. Is mentioned.

  Examples of the carboxylic acid salts include ammonium salts, primary amine salts such as methylamine, ethylamine, and t-butylamine, secondary amine salts such as dimethylamine, ethylmethylamine, and diethylamine, trimethylamine, diethylmethylamine, Examples thereof include tertiary amine salts such as ethyldimethylamine and triethylamine, quaternary ammonium salts such as tetramethylammonium, triethylmethylammonium and tetraethylammonium, imidazolinium salts and the like.

As a co-solvent mixed with ethylene glycol, water, glycols such as propylene glycol, lactones such as γ-butyrolactone, N-methyl-2-pyrrolidone, N-methylformamide, N, N-dimethylformamide Amides such as N-ethylformamide, N, N-diethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-ethylacetamide, N, N-diethylacetamide, hexamethylphosphoric amide, ethylene carbonate, Examples thereof include carbonates such as propylene carbonate and isobutylene carbonate, nitriles such as acetonitrile, oxides such as dimethyl sulfoxide, ethers, ketones, esters, sulfolane and sulfolane derivatives.
These solvents can be used alone or in combination of two or more.

In addition to the carboxylic acid and its salt and solvent, various additives can be added for the purpose of reducing leakage current, improving withstand voltage, and absorbing gas.
As additives, polymer compounds represented by random copolymers and block copolymers of phosphoric acid compounds, boric acid compounds, polyhydric alcohols, polyvinyl alcohol, polyethylene glycol, polypropylene glycol, polyoxyethylene polyoxypropylene glycol And nitro compounds.

As described above, the alkoxycarbonyldicarboxylic acid used in the electrolytic solution of the present invention is a compound having a carbonyl group, and this carbonyl group is preferentially adsorbed on the surface of the tab terminal or the crimped portion, and a protective film is formed on the surface. It is thought to prevent the reaction with chlorine, and it can suppress the corrosion disconnection of the crimp terminal between the tab terminal inside the electrolytic capacitor and the flange of the sealing plate and the tab terminal, thereby improving the product reliability. Can do.
In addition, since the structure also has a carboxyl group, the above effect can be obtained without impairing the conductivity of the electrolytic solution.
Furthermore, since it is a higher dicarboxylic acid, the withstand voltage of the electrolyte can be improved.

The alkoxycarbonyldicarboxylic acid described in [Chemical Formula 1] to [Chemical Formula 3] is added to an electrolytic solution containing ethylene glycol as a main component and dissolved in carboxylic acid or a salt thereof.
Hereinafter, the Example which melt | dissolved the alkoxycarbonyl dicarboxylic acid of [Chemical Formula 1]-[Chemical Formula 3] is demonstrated concretely.

  As the alkoxycarbonyldicarboxylic acid of [Chemical Formula 1], [Chemical Formula 4] to [Chemical Formula 8] shown below are used, and an electrolytic solution is prepared with the composition shown in Table 1, and the specific resistance of the electrolytic solution at 30 ° C. and at 85 ° C. The spark generation voltage (withstand voltage of the electrolyte) was measured, and the results shown in Table 1 were obtained.

４，６−ビスメトキシカルボニル−４，６−ジメチル−２，１２−ドデカンジカルボン酸

4,6-bismethoxycarbonyl-4,6-dimethyl-2,12-dodecanedicarboxylic acid

６−エトキシカルボニル−３−エチル−３−メトキシカルボニル−１，１０−デカンジカルボン酸

6-Ethoxycarbonyl-3-ethyl-3-methoxycarbonyl-1,10-decanedicarboxylic acid

４−エチル−７−メトキシカルボニル−４−プロポキシカルボニル−７−プロピル−１，１２−ドデカンジカルボン酸

4-Ethyl-7-methoxycarbonyl-4-propoxycarbonyl-7-propyl-1,12-dodecanedicarboxylic acid

２，７−ビスエトキシカルボニル−４−ノネン−１，９−ジカルボン酸

2,7-bisethoxycarbonyl-4-nonene-1,9-dicarboxylic acid

４−エトキシカルボニル−８−エチル−８−メトキシカルボニル−２，４，１１−トリメチル−２，１１−ドデカンジカルボン酸

4-Ethoxycarbonyl-8-ethyl-8-methoxycarbonyl-2,4,11-trimethyl-2,11-dodecanedicarboxylic acid

Next, an electrolytic solution prepared with the composition shown in Table 1 was impregnated into a capacitor element, and 100 69 type aluminum electrolytic capacitors each having a diameter of 35.0 mm, a length of 50.0 mm, a rated voltage of 450 V, and a capacitance of 470 μF were produced. did.
Of these, 50 were applied with a rated voltage for 5000 hours in a constant temperature bath at 105 ° C., and the remaining 50 were applied with a rated voltage for 5000 hours in a constant temperature bath at 115 ° C.
After 5000 hours, the capacitor was disassembled, the number of tab terminals that were broken by corrosion was investigated, and the results shown in Table 2 were obtained.

From the results of Table 2, it can be seen that Examples 1 to 14 in which the alkoxycarbonyldicarboxylic acid was dissolved suppressed the corrosion disconnection of the tab terminal as compared with the conventional examples 1 and 2 in which this was not dissolved.
However, if the amount of the alkoxycarbonyldicarboxylic acid dissolved is less than 0.1 wt%, the effect of suppressing the corrosion breakage of the tab terminal is not sufficient.
Moreover, even if the dissolution amount of the alkoxycarbonyldicarboxylic acid exceeds 5.0 wt%, the above effect is not changed, and a decrease in the withstand voltage of the electrolytic solution is observed as shown in Table 1. Therefore, 0.1 to 5.0 wt% The range of is preferable.

  As the alkoxycarbonyldicarboxylic acid of [Chemical Formula 2], [Chemical Formula 9] to [Chemical Formula 13] shown below are used, and an electrolytic solution is prepared with the composition shown in Table 3, and the specific resistance of the electrolytic solution at 30 ° C. and at 85 ° C. The spark generation voltage (withstand voltage of the electrolyte) was measured, and the results shown in Table 3 were obtained.

７，８−ビスメトキシカルボニル−７，８−ジメチル−１，１４−テトラデカンジカルボン酸

7,8-bismethoxycarbonyl-7,8-dimethyl-1,14-tetradecanedicarboxylic acid

４，５−ビスメトキシカルボニル−２，５−ジエチル−４−メチル−１，１１−ウンデカンジカルボン酸

4,5-bismethoxycarbonyl-2,5-diethyl-4-methyl-1,11-undecanedicarboxylic acid

３，４−ビスエトキシカルボニル−スベリン酸

3,4-bisethoxycarbonyl-suberic acid

６，７−ビスメトキシカルボニル−２，６，７，１１−テトラメチル−２，１１−ドデカンジカルボン酸

6,7-bismethoxycarbonyl-2,6,7,11-tetramethyl-2,11-dodecanedicarboxylic acid

８−エトキシカルボニル−２，８−ジメチル−７−プロポキシカルボニル−４−ノネン−２，９−ジカルボン酸

8-Ethoxycarbonyl-2,8-dimethyl-7-propoxycarbonyl-4-nonene-2,9-dicarboxylic acid

Next, an electrolytic solution prepared with the composition shown in Table 3 was impregnated with a capacitor element, and 100 69-type aluminum electrolytic capacitors each having a diameter of 35.0 mm, a length of 50.0 mm, a rated voltage of 450 V, and a capacitance of 470 μF were prepared. did.
Of these, 50 were applied with a rated voltage for 5000 hours in a constant temperature bath at 105 ° C., and the remaining 50 were applied with a rated voltage for 5000 hours in a constant temperature bath at 115 ° C.
After the lapse of 5000 hours, the capacitor was disassembled, and the number of corrosion breaks of the tab terminal was investigated. The results shown in Table 4 were obtained.

From the results of Table 4, it can be seen that in Examples 15 to 28 in which alkoxycarbonyldicarboxylic acid was dissolved, corrosion disconnection of the tab terminal was suppressed as compared with Conventional Examples 1 and 2 in which this was not dissolved.
However, if the amount of the alkoxycarbonyldicarboxylic acid dissolved is less than 0.1 wt%, the effect of suppressing the corrosion breakage of the tab terminal is not sufficient.
In addition, even if the dissolution amount of alkoxycarbonyldicarboxylic acid exceeds 5.0 wt%, the above effect does not change, and the withstand voltage drop of the electrolyte solution is seen as shown in Table 3, so 0.1 to 5.0 wt% A range is preferred.

  As the alkoxycarbonyldicarboxylic acid of [Chemical Formula 3], the following chemical compounds of [Chemical Formula 14] to [Chemical Formula 18] are used, an electrolytic solution is prepared with the composition shown in Table 5, and the specific resistance of the electrolytic solution at 30 ° C. and 85 The spark generation voltage (withstand voltage of the electrolyte) at ℃ was measured, and the results shown in Table 5 were obtained.

４−メトキシカルボニル−４−メチル−２，１０−デカンジカルボン酸

4-methoxycarbonyl-4-methyl-2,10-decanedicarboxylic acid

６−エトキシカルボニル−２，６，１０−トリメチル−２，１０−ウンデカンジカルボン酸

6-Ethoxycarbonyl-2,6,10-trimethyl-2,10-undecanedicarboxylic acid

７，９−ジメチル−８−プロポキシカルボニル−３，１４−ヘキサデカンジカルボン酸

7,9-Dimethyl-8-propoxycarbonyl-3,14-hexadecanedicarboxylic acid

４−ブトキシカルボニル−アゼライン酸

4-Butoxycarbonyl-azeleic acid

８−メトキシカルボニル−５−ドデセン−１，１２−ジカルボン酸

8-Methoxycarbonyl-5-dodecene-1,12-dicarboxylic acid

Next, an electrolytic solution prepared with the composition shown in Table 5 was impregnated with a capacitor element, and 100 69 type aluminum electrolytic capacitors each having a diameter of 35.0 mm, a length of 50.0 mm, a rated voltage of 450 V, and a capacitance of 470 μF were prepared. did.
Of these, 50 were applied with a rated voltage for 5000 hours in a constant temperature bath at 105 ° C., and the remaining 50 were applied with a rated voltage for 5000 hours in a constant temperature bath at 115 ° C.
After the lapse of 5000 hours, the capacitor was disassembled, and the number of corrosion breaks of the tab terminal was investigated. The results shown in Table 6 were obtained.

From the results of Table 6, it can be seen that in Examples 29 to 42 in which the alkoxycarbonyldicarboxylic acid was dissolved, the corrosion disconnection of the tab terminal was suppressed as compared with the conventional examples 1 and 2 in which this was not dissolved.
Here, if the dissolution amount of the alkoxycarbonyldicarboxylic acid is less than 0.1 wt%, the effect of suppressing the corrosion breakage of the tab terminal is not sufficient.
Further, from the results of Table 1, the above effect is not changed even when the dissolution amount of alkoxycarbonyldicarboxylic acid exceeds 5.0 wt%, and the withstand voltage of the electrolytic solution is lowered as shown in Table 5. A range of ˜5.0 wt% is preferred.

  In addition, this invention is not limited to the said Example, The electrolyte solution which melt | dissolved various solutes illustrated previously individually or in multiple, the electrolyte solution which added the additive mentioned above, and the electrolyte solution which mixed the subsolvent There was also an effect equivalent to that of the above-described embodiment.

Claims (2)

An electrolytic solution for driving an electrolytic capacitor, wherein a carboxylic acid or a salt thereof and an alkoxycarbonyldicarboxylic acid represented by the following chemical formulas (Chemical Formula 1 to Chemical Formula 3) are dissolved in a solvent having ethylene glycol as a main component: .

A ₁ , A ₂ , A ₃ : a hydrocarbon group having 1 to 18 carbon atoms.
A ₁ , A ₂ , and A ₃ may be the same or different.
a ₁ , a ₂ : a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms.
OR ₁ , OR ₂ : an alkoxyl group.
OR ₁ and OR ₂ may be the same or different.

_{A 1,} A _2: hydrocarbon group having 1 to 18 carbon atoms.
A ₁ and A ₂ may be the same or different.
a ₁ , a ₂ : a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms.
OR ₁ , OR ₂ : an alkoxyl group.
OR ₁ and OR ₂ may be the same or different.

A _{1, A 2:} hydrocarbon group _A 1 1 to 18 carbon atoms, _{A 2} may be the same or different.
a ₁ : a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms.
OR ₁ : an alkoxyl group.   An electrolytic solution for driving an electrolytic capacitor, wherein the amount of the alkoxycarbonyldicarboxylic acid according to claim 1 is 0.1 to 5.0 wt%.