JP4540199B2 - Electrolytic solution for driving electrolytic capacitors - Google Patents

Description

【０００８】
有機溶媒としては、プロトン系溶媒のエチルアルコール、プロピルアルコール、ブチルアルコール等の一価アルコール類、エチレングリコール、ジエチレングリコール、トリエチレングリコール、プロピレングリコール等の二価アルコール類、グリセリン等の三価アルコール類、メチルセルソルブ、エチルセルソルブ等のアルコールエーテル類を挙げることができ、また非プロトン系溶媒のγ−ブチロラクトン等のラクトン類、Ｎ−メチルホルムアミド、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ−エチルアセトアミド等のアミド系溶媒、ジメチルスルホキシド等のオキシド系溶媒を挙げることができる。
【０００９】
カルボン酸としては、ギ酸、酢酸、プロピオン酸、エナント酸等の脂肪族モノカルボン酸、マロン酸、コハク酸、グルタル酸、アジピン酸、スベリン酸、アゼライン酸、セバシン酸、デカンジカルボン酸、マレイン酸等の脂肪族ジカルボン酸、安息香酸、フタル酸、サリチル酸等の芳香族カルボン酸を挙げることができる。
【００１０】
無機酸としては、ホウ酸、リン酸、亜リン酸、次亜リン酸、スルファミン酸等を挙げることができる。
【００１１】
それらの塩としては、メチルアミン、エチルアミン等の１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２級アミン、トリメチルアミン、ジメチルエチルアミン、ジエチルメチルアミン、トリエチルアミン等の３級アミン、テトラメチルアンモニウム、テトラエチルアンモニウム等の４級アンモニウム塩、アンモニウム塩、イミダゾリニウム塩を挙げることができる。
【００１２】
【発明の実施の形態】
ミリセチンはナフタレン骨格に６つのＯＨ基を有する化合物であり、このＯＨ基が電解コンデンサ内の残存酸素と反応し、ラジカル連鎖熱反応を抑制する。また、電極箔と水や酸などの反応を抑制することで、容量変化も抑えることができる。さらに、ＯＨ基周辺にカルボニル基、他のＯＨ基、ベンゼン環などが存在するためアミド類などが生成しにくく、電解液比抵抗の上昇を抑え、製品ｔａｎδ上昇を抑えることができる。
【００１３】
【実施例】
本発明の実施例について具体的に説明する。表１の組成で電解液を調合し、３０℃における比抵抗を測定した。
【００１４】
【表１】

【００１５】
表１の各電解液を、陽極箔と陰極箔とをセパレータ紙を介して巻回したコンデンサ素子に含浸した後、アルミニウム製外装ケース内に封口ゴムと共に挿入し、直径１０ｍｍ、長さ１２．５ｍｍ、定格電圧５０Ｖ、静電容量１５０μＦのアルミ電解コンデンサを製作しエージングを行った。
上記製品を１０５℃の恒温槽中で３０００時間定格電圧を印加したときの容量変化率とｔａｎδを表２に示す。
【００１６】
【表２】

【００１７】
表２より、ミリセチンを添加すると容量変化率とｔａｎδ変化を抑えることができることが分かる。なお、表２よりミリセチンの添加量が多いほどその効果が大きいことが分かるが、ミリセチンを添加すると比抵抗が上昇することから、その添加量は０．１〜５．０ｗｔ％が好ましい。
【００１８】
なお、溶媒として混合する水の量を実施例では１３ｗｔ％としたが、本発明はこれに限定されるものではなく、電解液の低比抵抗化を進めるためには、５〜６０ｗｔ％が好ましい。
【００１９】
【発明の効果】
上記のとおり本発明による電解液は、有機溶媒と水からなる混合溶媒に、ミリセチンを混合することで電解コンデンサの容量変化、ｔａｎδの上昇を抑制することができ、長期信頼性を向上させることが可能である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in an electrolytic solution for driving an electrolytic capacitor (hereinafter referred to as an electrolytic solution).
[0002]
[Prior art]
Conventionally, the electrolytic solution for low-pressure aluminum electrolytic capacitors has been intended to maintain long-term reliability by adding ammonium adipate as the main solute to a solvent consisting of ethylene glycol and water and adding additives such as phosphoric acid, mannitol, and sorbitol. .
[0003]
[Problems to be solved by the invention]
However, in a solvent mixed with water, the electrode foil is likely to be hydrated and deteriorated, and the electrolyte solution deteriorates due to the heat generated from the outside and the heat generated by the capacitor, resulting in the formation of amides. There was a problem that the product characteristics deteriorated. Therefore, even in an electrolytic solution in which water is mixed in a solvent, there has been a demand for means that can prevent hydration deterioration of the electrode foil and suppress an increase in specific resistance of the electrolytic solution.
[0004]
[Means for Solving the Problems]
The present invention has been found as a result of studies to solve the above-mentioned problems. By adding myricetin having six OH groups in the molecule, hydration deterioration of the electrode foil and deterioration of the electrolyte solution can be achieved. It is something to be suppressed. That is, to a mixed solvent composed of an organic solvent and water, at least one of a carboxylic acid, an inorganic acid, or a salt thereof is a main solute, and 0.1 to 5.0 wt% of myricetin (Chemical Formula 2) is added and water is added. The electrolytic solution for driving an electrolytic capacitor is characterized in that the mixed amount of is 5 to 60 wt% .
[0005]
[Chemical 2]

[0008]
As the organic solvent, monohydric alcohols such as ethyl alcohol, propyl alcohol and butyl alcohol as proton solvents, dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol and propylene glycol, trihydric alcohols such as glycerin, Examples include alcohol ethers such as methyl cellosolve and ethyl cellosolve, and lactones such as γ-butyrolactone as an aprotic solvent, N-methylformamide, N, N-dimethylformamide, N-ethylacetamide and the like. Examples thereof include amide solvents and oxide solvents such as dimethyl sulfoxide.
[0009]
Carboxylic acids include aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, enanthic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, etc. And aromatic carboxylic acids such as aliphatic dicarboxylic acid, benzoic acid, phthalic acid, and salicylic acid.
[0010]
Examples of inorganic acids include boric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, sulfamic acid, and the like.
[0011]
These salts include primary amine salts such as methylamine and ethylamine, secondary amines such as dimethylamine, ethylmethylamine and diethylamine, tertiary amines such as trimethylamine, dimethylethylamine, diethylmethylamine and triethylamine, and tetramethylammonium. And quaternary ammonium salts such as tetraethylammonium, ammonium salts, and imidazolinium salts.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Myricetin is a compound having six OH groups in the naphthalene skeleton, and this OH group reacts with residual oxygen in the electrolytic capacitor to suppress radical chain heat reaction. Moreover, a capacity | capacitance change can also be suppressed by suppressing reaction of electrode foil, water, an acid, etc. Furthermore, since a carbonyl group, another OH group, a benzene ring, and the like are present around the OH group, amides and the like are hardly generated, and an increase in the specific resistance of the electrolytic solution can be suppressed and an increase in the product tan δ can be suppressed.
[0013]
【Example】
Examples of the present invention will be specifically described. An electrolyte solution was prepared with the composition shown in Table 1, and the specific resistance at 30 ° C. was measured.
[0014]
[Table 1]

[0015]
Each electrolytic solution in Table 1 was impregnated into a capacitor element in which an anode foil and a cathode foil were wound through separator paper, and then inserted into an aluminum outer case together with a sealing rubber, and had a diameter of 10 mm and a length of 12.5 mm. An aluminum electrolytic capacitor having a rated voltage of 50 V and a capacitance of 150 μF was manufactured and aged.
Table 2 shows the rate of change in capacity and tan δ when the rated voltage is applied to the product in a thermostat at 105 ° C. for 3000 hours.
[0016]
[Table 2]

[0017]
From Table 2, it can be seen that addition of myricetin can suppress the capacity change rate and tan δ change. In addition, although it turns out that the effect is so large that there is much addition amount of myricetin from Table 2, since specific resistance will raise when myricetin is added, the addition amount is 0.1-5.0 wt%.
[0018]
The amount of water to be mixed as a solvent is 13 wt% in the examples, but the present invention is not limited to this, and 5 to 60 wt% is preferable in order to reduce the specific resistance of the electrolytic solution. .
[0019]
【The invention's effect】
As described above, the electrolytic solution according to the present invention can suppress the capacitance change of the electrolytic capacitor and the increase in tan δ by mixing myricetin with a mixed solvent composed of an organic solvent and water, thereby improving long-term reliability. Is possible.

Claims (1)

To a mixed solvent composed of an organic solvent and water, at least one of carboxylic acid, inorganic acid, or salt thereof is used as a main solute, and 0.1 to 5.0 wt% of myricetin (Chemical Formula 1) is added and water is mixed. An electrolytic solution for driving an electrolytic capacitor, wherein the amount is 5 to 60 wt% .