JP4150251B2 - Electrolytic solution for driving electrolytic capacitors - Google Patents

Description

【０００８】
本発明に係る電解液では、ニペコチン酸がアルミニウムイオンと錯体を形成することから、高温でリプル電流が印加され、電解コンデンサ内部が雰囲気温度より高温になるような過酷な条件下においても、アルミニウム電極箔の水和劣化を抑制することが可能となり、電解コンデンサの更なる長寿命化を図ることができる。
【０００９】
本発明において、ニペコチン酸の溶解量は、電解液全体に対して０．１〜２．０ｗｔ％であることが好ましい。ニペコチン酸の溶解量が０．１ｗｔ％未満ではアルミニウム電極箔の水和劣化を抑制する効果が少なく、２．０ｗｔ％を超えると、溶質が析出しやすくなる傾向にある。
【００１０】
本発明において、カルボン酸としては、アゼライン酸、セバシン酸、１，６−デカンジカルボン酸、５，６−デカンジカルボン酸、７−ビニルヘキサデセン−１，１６−ジカルボン酸等を例示することができる。
【００１１】
そして、カルボン酸の塩、またはホウ酸の塩としては、アンモニウム塩の他、メチルアミン、エチルアミン、ｔ−ブチルアミン等の一級アミン塩、ジメチルアミン、エチルメチルアミン、ジエチルアミン等の二級アミン塩、トリメチルアミン、ジエチルメチルアミン、エチルジメチルアミン、トリエチルアミン等の三級アミン塩、テトラメチルアンモニウム、トリエチルメチルアンモニウム等の四級アンモニウム塩等を例示することができる。
【００１２】
また、溶媒としては、エチレングリコール、プロピレングリコール等の多価アルコールを１種、あるいは２種以上を配合したものを主溶媒とし、必要に応じて、水、γ−ブチロラクトン、Ｎ−メチル−２−ピロリドン等のラクトン類、Ｎ−メチルホルムアミド、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ−エチルホルムアミド、Ｎ，Ｎ−ジエチルホルムアミド、Ｎ−メチルアセトアミド、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ−エチルアセトアミド、Ｎ，Ｎ−ジエチルアセトアミド、ヘキサメチルホスホリックアミド等のアミド類、エチレンカーボネート、プロピレンカーボネート、イソブチレンカーボネート等の炭酸類、アセトニトリル等のニトリル類、ジメチルスルホキシド等のオキシド類、エーテル類、ケトン類、エステル類等を副溶媒として配合したものを例示することができる。
【００１３】
【発明の実施の形態】
本発明に係る電解液では、エチレングリコールなどの多価アルコールを主溶媒とし、カルボン酸若しくはその塩、および／または、ホウ酸若しくはその塩と、ニペコチン酸とを溶解する。ここで、ニペコチン酸の溶解量は、電解液全体に対して０．１〜２．０ｗｔ％とする。
【００１４】
このような電解液では、ニペコチン酸がアルミニウムイオンと錯体を形成することから、高温でリプル電流が印加され、電解コンデンサ内部が雰囲気温度より高温になるような過酷な条件下においても、アルミニウム電極箔の水和劣化を抑制することが可能となり、電解コンデンサの更なる長寿命化を図ることができる。
【００１５】
【実施例】
以下、本発明を実施例に基づき具体的に説明する。まず、表１に示す電解液組成で電解液を調合した後、定格４５０Ｖ／２７０μＦ用コンデンサ素子に各電解液を含浸する。次に、陽極・陰極リード線と外部端子を有する封口体とを接続してコンデンサケースに組み込んだ後、封口したアルミニウム電解コンデンサを作製する。次に、各電解コンデンサにおいて、１０５℃の恒温槽中でリプル電流重畳試験を実施した。リプル電流は製品温度上昇が１０℃となる電流値を用いた。そして、試験開始後１０００時間毎に製品を分解してアルミニウム電極箔の水和劣化の有無を確認し、表１に示す結果を得た。
【００１６】
【表１】

【００１７】
表１に示すように、ニペコチン酸を溶解しなかった従来例は、３０００〜４０００時間でアルミニウム電極箔が水和劣化した。これに対して、ニペコチン酸を溶解した実施例に係る電解コンデンサでは、５０００時間経過してもアルミニウム電極箔の水和劣化はみられなかった。
【００１８】
なお、ニペコチン酸の配合量は０．１ｗｔ％未満ではアルミニウム電極箔の水和劣化抑制効果が少なく、２．０ｗｔ％を超える場合は、製品が０℃以下の低温で放置されると溶質が析出しやすくなるため、ニペコチン酸の配合量は、０．１〜２．０ｗｔ％の範囲が好ましい。
【００１９】
なお、本発明は実施例に限定されるものではなく、先に例示した溶媒、カルボン酸またはその塩を単独または複数用いても実施例と同等の効果があり、耐洗浄剤としてニトロ化合物を溶解してもよい。
【００２０】
【発明の効果】
以上説明したように、本発明に係る電解液では、ニペコチン酸を溶解しているため、高温・リプル重畳で長時間使用してもアルミニウム電極箔の水和劣化を抑制することができる。従って、電解コンデンサの長寿命化を図ることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of an electrolytic solution for driving an electrolytic capacitor (hereinafter referred to as an electrolytic solution), and particularly to a technique for extending the life of an electrolytic capacitor.
[0002]
[Prior art]
Conventionally, an electrolytic capacitor for medium and high pressures uses an electrolytic solution in which a carboxylic acid or an ammonium salt thereof is dissolved in a solvent containing ethylene glycol as a main component (see, for example, Patent Documents 1 and 2).
[0003]
[Patent Document 1]
Japanese Patent Publication No. 7-48460 (2nd page, table)
[Patent Document 2]
Japanese Patent Publication No. 7-63047 (Page 3, Table 1)
[0004]
[Problems to be solved by the invention]
However, with regard to electrolytic capacitors, usage conditions are becoming harsh, such as a large ripple current being applied at high temperatures, and when used for a long time under such conditions, the aluminum electrode foil is not contained in the electrolytic solution in conventional electrolytic solutions. There is a problem of hydration deterioration by water.
[0005]
In view of the above problems, the object of the present invention is to prevent the hydration deterioration of the aluminum electrode foil even in a severe situation where a ripple current is applied at a high temperature, thereby further extending the life. An electrolytic solution for driving an electrolytic capacitor is provided.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, in the electrolytic solution according to the present invention, a polyhydric alcohol is used as a main solvent, carboxylic acid or a salt thereof, and / or boric acid or a salt thereof, and nipecotic acid represented by the following chemical formula: Is dissolved.
[0007]
[Chemical 2]

[0008]
In the electrolytic solution according to the present invention, since nipecotic acid forms a complex with aluminum ions, the ripple current is applied at a high temperature, and even under severe conditions such that the inside of the electrolytic capacitor is higher than the ambient temperature, the aluminum electrode Hydration deterioration of the foil can be suppressed, and the life of the electrolytic capacitor can be further extended.
[0009]
In the present invention, the amount of nipecotic acid dissolved is preferably 0.1 to 2.0 wt% with respect to the entire electrolytic solution. If the amount of nipecotic acid dissolved is less than 0.1 wt%, the effect of suppressing hydration deterioration of the aluminum electrode foil is small, and if it exceeds 2.0 wt%, the solute tends to precipitate.
[0010]
In the present invention, examples of the carboxylic acid include azelaic acid, sebacic acid, 1,6-decanedicarboxylic acid, 5,6-decanedicarboxylic acid, 7-vinylhexadecene-1,16-dicarboxylic acid and the like.
[0011]
In addition to ammonium salts, primary amine salts such as methylamine, ethylamine and t-butylamine, secondary amine salts such as dimethylamine, ethylmethylamine and diethylamine, trimethylamine, and the like as carboxylic acid salts or boric acid salts And tertiary amine salts such as diethylmethylamine, ethyldimethylamine and triethylamine, and quaternary ammonium salts such as tetramethylammonium and triethylmethylammonium.
[0012]
Moreover, as a solvent, what mixed polyhydric alcohols, such as ethylene glycol and propylene glycol, with 1 type, or 2 or more types is made into a main solvent, and water, (gamma) -butyrolactone, N-methyl-2- 2 as needed. Lactones such as pyrrolidone, N-methylformamide, N, N-dimethylformamide, N-ethylformamide, N, N-diethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-ethylacetamide, N, N -Amides such as diethylacetamide and hexamethylphosphoric amide, carbonates such as ethylene carbonate, propylene carbonate and isobutylene carbonate, nitriles such as acetonitrile, oxides such as dimethyl sulfoxide, ethers, ketones and esters As a co-solvent It may be exemplified those combined.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In the electrolytic solution according to the present invention, a polyhydric alcohol such as ethylene glycol is used as a main solvent, and carboxylic acid or a salt thereof and / or boric acid or a salt thereof and nipecotic acid are dissolved. Here, the amount of nipecotic acid dissolved is 0.1 to 2.0 wt% with respect to the entire electrolyte.
[0014]
In such an electrolyte solution, nipecotic acid forms a complex with aluminum ions, so that the ripple current is applied at high temperature, and the aluminum electrode foil is used even under severe conditions where the inside of the electrolytic capacitor is higher than the ambient temperature. It is possible to suppress the hydration deterioration of the electrolytic capacitor, and it is possible to further extend the life of the electrolytic capacitor.
[0015]
【Example】
Hereinafter, the present invention will be specifically described based on examples. First, after preparing an electrolytic solution with the electrolytic solution composition shown in Table 1, a capacitor element for a rated 450 V / 270 μF is impregnated with each electrolytic solution. Next, an anode / cathode lead wire and a sealing body having an external terminal are connected and assembled in a capacitor case, and then a sealed aluminum electrolytic capacitor is produced. Next, each electrolytic capacitor was subjected to a ripple current superposition test in a constant temperature bath at 105 ° C. As the ripple current, a current value at which the product temperature rise is 10 ° C. was used. And the product was decomposed | disassembled every 1000 hours after the test start, the presence or absence of the hydration deterioration of the aluminum electrode foil was confirmed, and the result shown in Table 1 was obtained.
[0016]
[Table 1]

[0017]
As shown in Table 1, in the conventional example in which nipecotic acid was not dissolved, the aluminum electrode foil was hydrated and deteriorated in 3000 to 4000 hours. On the other hand, in the electrolytic capacitor according to the example in which nipecotic acid was dissolved, hydration deterioration of the aluminum electrode foil was not observed even after 5000 hours.
[0018]
If the amount of nipecotic acid is less than 0.1 wt%, the effect of suppressing the hydration deterioration of the aluminum electrode foil is small. If it exceeds 2.0 wt%, the solute precipitates when the product is left at a low temperature of 0 ° C or lower. Therefore, the amount of nipecotic acid is preferably in the range of 0.1 to 2.0 wt%.
[0019]
Note that the present invention is not limited to the examples, and the use of the solvent, carboxylic acid or salt thereof exemplified above alone or in combination has the same effect as the examples, and dissolves the nitro compound as a detergent-resistant agent. May be.
[0020]
【The invention's effect】
As described above, in the electrolytic solution according to the present invention, nipecotic acid is dissolved, so that hydration deterioration of the aluminum electrode foil can be suppressed even when used for a long time at high temperature and ripple superposition. Therefore, the lifetime of the electrolytic capacitor can be extended.

Claims (2)

An electrolytic solution for driving an electrolytic capacitor using an aluminum electrode foil,
An electrolytic solution for driving an electrolytic capacitor, wherein a polyhydric alcohol is used as a main solvent, and carboxylic acid or a salt thereof and / or boric acid or a salt thereof and nipecotic acid represented by the following chemical formula are dissolved.

The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the amount of nipecotic acid dissolved is 0.1 to 2.0 wt%.