JP2008177197A - Electrolytic solution for driving electrolytic capacitor and electrolytic capacitor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic solution for driving which has stability even in high temperature and high humidity and long lifetime, and a highly reliable electrolytic capacitor using the same. <P>SOLUTION: The electrolytic solution for driving an electrolytic capacitor contains an electrolyte composed of an organic solvent containing an anionic salt having a skeleton of boron complex expressed by chemical formula 1 (wherein, R<SP>1</SP>and R<SP>2</SP>are each the same or different hydrogen atom, alkyl group of 1-4C or phenyl group), and a cationic salt having an amidine composition skeleton expressed by chemical formula 2 (wherein, R<SP>1</SP>and R<SP>3</SP>are each the same or different hydrocarbon group of 1-4C, and R<SP>2</SP>is a hydrogen atom or hydrocarbon group of 1-4C). In addition, the electrolytic solution contains at least a boric acid as an additive. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrolytic solution for driving an electrolytic capacitor used for an electronic component of an electronic device, and an electrolytic capacitor using the electrolytic solution.

  Conventionally, as an electrolytic solution for driving an electrolytic capacitor or the like, a quaternary ammonium salt of aromatic carboxylic acid (phthalic acid or the like) as an electrolyte (for example, see Patent Document 1), a quaternary ammonium salt of maleic acid Using electrolytes (for example, see Patent Document 2), those using quaternary ammonium salts of aliphatic saturated monocarboxylic acids (such as formic acid) as electrolytes (for example, see Patent Document 3), aliphatic saturated dicarboxylic acids ( Known are those using a quaternary ammonium salt of malonic acid or the like as an electrolyte (for example, see Patent Document 4).

In addition, γ-butyrolactone is the main solvent, imidazolium quaternized cyclic amidine compound as a solute is used as a cation component, and an acid conjugate base is used as an anion component as a driving electrolyte for reducing the low impedance of an electrolytic capacitor. What dissolved the salt is used (for example, refer patent document 5).
Japanese Patent Laid-Open No. 62-145715 Japanese Patent Laid-Open No. 62-145713 JP-A-62-226614 Japanese Patent Laid-Open No. 62-248217 JP 08-32439 A

  However, in the above-mentioned conventional electrolytic capacitors, those using quaternary ammonium salts of phthalic acid as electrolytes have insufficient conductivity, and those using quaternary ammonium salts such as maleic acid, formic acid and malonic acid as electrolytes Had insufficient stability at high temperatures.

  In addition, the electrolytic solution using a quaternary ammonium salt as an electrolyte has problems such as deterioration or corrosion of the resin, rubber, or metal that is a material constituting the capacitor due to electrochemical modification of the quaternary ammonium. there were.

  On the other hand, using an electrolyte in which a salt containing an imidazolium quaternized cyclic amidine compound as a cation component and an acid conjugate base as an anion component can be used, a high conductivity can be obtained. There is a problem that a strong alkali is generated, the sealing alkali is eroded by the strong alkali, and the driving electrolyte solution leaks.

  An object of the present invention is to solve such conventional problems, to provide a driving electrolyte that is stable and has a long life even under high temperature and high humidity, and to provide a highly reliable electrolytic capacitor using the electrolytic solution. is there.

  In order to solve the above problems, the present invention contains, in an organic solvent, an electrolyte comprising an anion salt having a boron complex skeleton represented by (Chemical Formula 1) and a cation salt having an amidine compound skeleton represented by (Chemical Formula 2). In addition, an electrolytic solution for driving an electrolytic capacitor is characterized by containing at least boric acid as an additive.

  In addition, the boron complex represented by the above (Chemical Formula 1) includes borodisalicylic acid, borodiglycolic acid, borodisoxalic acid, borodimalonic acid, borodisuccinic acid, borodiadipic acid, borodimaleic acid, borodilactic acid, borodimalic acid, boroditartaric acid, borodicitric acid, borodiphthalate It is at least one selected from the group consisting of acid, borodi (2-hydroxy) isobutyric acid, borodimandelic acid and borodi (3-hydroxy) propionic acid.

  The concentration of the electrolyte composed of the boron complex skeleton and the amidine compound skeleton is 10 to 50 parts by weight, and the amount of boric acid added is 0.5 to 3 parts by weight.

  Moreover, it is characterized by including at least 1 type of a phosphorus compound and a polysaccharide as an additive, The addition amount of a phosphorus compound is 0.5-2 weight part, and the addition amount of a polysaccharide is 0.5- 2 parts by weight.

  The organic solvent is mainly γ-butyrolactone, ethylene glycol, sulfolane or a mixed solution thereof.

  And it is set as the electrolytic capacitor using the said electrolyte solution for electrolytic capacitor drive.

  The present invention contains an electrolyte composed of an anionic salt having a boron complex skeleton represented by (Chemical Formula 1) and a cation salt of an amidine compound skeleton represented by (Chemical Formula 2) in an organic solvent, and at least boric acid as an additive. By using a driving electrolyte solution containing, a driving electrolyte solution having high conductivity can be obtained, and hydrolysis of the boron complex is suppressed even under high temperature and high humidity, and an electrolytic capacitor having stable characteristics can be obtained. Can do.

  Moreover, by setting the concentration of the electrolyte composed of the boron complex skeleton and the amidine compound skeleton in the range of 10 to 50 parts by weight, a driving electrolyte solution having high conductivity can be obtained. When the concentration of the electrolyte is less than 10 parts by weight and exceeds 50 parts by weight, the conductivity is remarkably lowered.

  In addition, when the addition amount of boric acid is in the range of 0.5 to 3 parts by weight, the pH of the driving electrolyte can be adjusted, and generation of strong alkali can be suppressed.

(Embodiment)
An electrolytic solution for driving an electrolytic capacitor according to an embodiment of the present invention includes an anion salt having a boron complex skeleton represented by (Chemical Formula 1) in an organic solvent and a cation salt having an amidine compound skeleton represented by (Chemical Formula 2). And an electrolytic solution for driving an electrolytic capacitor containing at least boric acid as an additive.

  The organic solvent is mainly composed of at least one of γ-butyrolactone, ethylene glycol, sulfolane or a mixed solution thereof.

  Examples of the anion salt having a boron complex skeleton represented by the above (Chemical Formula 1) include borodisalicylic acid, borodiglycolic acid, borodisoxalic acid, borodimalonic acid, borodisuccinic acid, borodiadipic acid, borodimaleic acid, borodilactic acid, borodimalic acid, boroditartaric acid, Examples include borodicitric acid, borodiphthalic acid, borodi (2-hydroxy) isobutyric acid, borodimandelic acid, and borodi (3-hydroxy) propionic acid. desirable.

  This anion salt having a boron complex skeleton can suppress the hydrolysis reaction in the presence of boric acid, and can maintain high electrical conductivity. The content of boric acid is preferably in the range of 0.5 to 3 parts by weight. When the content is less than 0.5 parts by weight, the effect is small. Adversely affect.

  In addition, as the cation salt of the amidine compound skeleton represented by the above (Chemical Formula 2), 1,3-dimethylimidazolium, 1,3-diethylimidazolium, 1,2,3-trimethylimidazolium, 1,2,3, 4-tetramethylimidazolium, 1,3-dimethyl-2-ethylimidazolium, 1,2-dimethyl-3-ethylimidazolium, 1,2,3-triethylimidazolium, 1,2,3,4-tetraethyl Imidazolium, 1,3-dimethyl-2-phenylimidazolium, 1,3-dimethyl-2-benzylimidazolium, 1-benzyl-2,3-dimethyl-imidazolium, 1-methyl-3-ethylimidazolium, etc. Is mentioned.

  These imidazolium compounds, unlike ordinary amine salts and quaternized ammonium salts thereof, have a delocalized N—C—N amidine group that is quaternized, so that the cation is resonance-stabilized. As a result, ion dissociation is promoted and high conductivity is obtained.

  Further, by introducing an alkyl group at the 2-position or 4-position of the imidazolium ring, the thermal stability of the imidazolium ring is improved, so that gas generation is small.

  Furthermore, even when hydroxide ions are generated by an electrochemical reaction in the electrolyte, the electrolytic product disappears quickly due to the reaction between the hydroxide ions and the amidine group of N—C—N, and the decomposition and ring opening. Therefore, the resin, rubber, and metal that are materials constituting the electrolytic capacitor are not deteriorated or corroded.

  The electrolyte content in the driving electrolyte is desirably in the range of 10 to 50 parts by weight, and when the addition amount is less than 10 parts by weight and exceeds 50 parts by weight, the conductivity is significantly lowered.

  The additive to be added to the driving electrolyte includes at least one of a phosphorus compound and a polysaccharide. The addition amount of the phosphorus compound is in the range of 0.5 to 2 parts by weight, and the addition amount of the polysaccharide. Is in the range of 0.5 to 2 parts by weight.

  Examples of the phosphorus compound include orthophosphoric acid, phosphorous acid, hypophosphorous acid, and salts thereof, and examples of the salt include ammonium salt, aluminum salt, sodium salt, calcium salt, and potassium salt. In addition, phosphoric acid compounds such as ethyl phosphate, diethyl phosphate, butyl phosphate, and dibutyl phosphate, phosphonic acid compounds such as 1-hydroxyethylidene-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, and phenylphosphonic acid Is mentioned. Moreover, phosphinic acid compounds, such as methylphosphinic acid and butyl phosphinate, are mentioned. Monophosphoric acid is particularly desirable as the phosphorus compound, and if the added amount is less than 0.5 parts by weight, the effect is small, and if the added amount is more than 2 parts by weight, the product characteristics are adversely affected.

  Examples of the polysaccharide include mannitol, xylit, sorbit, and the like, and xylit is particularly preferable. The addition amount is preferably in the range of 0.5 to 2 parts by weight, and if it is less than 0.5 parts by weight or exceeds 2 parts by weight, the effect of high temperature and high humidity cannot be obtained.

  Next, specific examples of the present embodiment will be described, but the present invention is not limited thereto.

  As shown in FIG. 1, the electrolytic capacitor used in this example is an anode foil as an anode electrode made of an aluminum foil and a cathode foil as a cathode electrode also made of an aluminum foil, with a separator interposed therebetween. The internal element 11 is formed by winding in such a manner that lead wires 12 are connected to the anode foil and the cathode foil of the internal element 11 respectively. The internal element 11 having such a configuration is impregnated with a driving electrolyte, and the internal element 11 is sealed in an aluminum case 15 and sealed with a sealing material 14 such as rubber or phenol resin, thereby forming an electrolytic capacitor.

  About the said electrolyte solution for a drive, the composition of each Example and each comparative example is shown in (Table 1).

  Winding-type radial lead type electrolytic capacitors (rated voltage 6.3 V, capacitance 820 μF, size; as shown in FIG. 1) using the driving electrolytes of Examples 1 to 7 and Comparative Examples 1 and 2; φ10 mm × L12.5 mm) was produced. Resin vulcanized butyl rubber was used as the sealing rubber. In addition, the water | moisture content in the electrolyte solution for a drive was adjusted to 8% so that the effect in moisture resistance could be clarified more.

  Next, the electrolytic capacitor was allowed to stand at 105 ° C., and the capacitance change rate (ΔC), loss angle tangent (tan δ), and leakage current (LC) after 3000 hours were measured. The results are shown in (Table 2). Further, as a liquid leakage test, a rated voltage was applied at 85 ° C. and 85% RH under humidity resistance, and the state of the sealed portion after 3000 hours was observed. The results are shown in (Table 3).

  Further, for the reflow bulge test, a winding-type chip electrolytic capacitor (rated voltage 6.3 V, electrostatic capacity 220 μF, size; using the driving electrolytes of Examples 1 and 2 and Comparative Examples 1 and 2 above; (φ6.3 mm × L5.8 mm). Resin vulcanized butyl rubber was used as the sealing rubber. The heat resistance was evaluated under reflow conditions of a reflow top temperature of 255 ° C., 230 ° C. for 30 seconds or more, and 200 ° C. for 70 seconds or more. Reflow was evaluated twice.

  As apparent from Table 2, the characteristics of the driving electrolyte solution of Example 1 that does not contain boric acid are large. However, the driving electrolyte solutions of Examples 2 to 7 have all the characteristics even after 3000 hours. It can be seen that even when compared with Comparative Example 1, the characteristic change is equivalent or better.

  Moreover, in the electrolytic capacitors of Examples 3 to 5, those in which the content of the electrolyte was changed to 10, 30, and 50 parts by weight did not decrease the conductivity of the driving electrolyte solution, and the capacitance change rate. The loss tangent and leakage current are small.

  Further, as is clear from (Table 3), it was found that the electrolytic capacitors of Examples 1 to 7 were superior in liquid leakage compared to Comparative Examples 1 and 2.

  Further, as apparent from Table 4, the tertiary amine salt electrolyte of Comparative Example 1 had poor high-temperature reflow swell characteristics, but by using the driving electrolyte of each Example, the rubber swell of the product Was also very small and showed good results.

  Next, six types of phosphoric compounds, monophosphoric acid, tributyl phosphate, triphenyl phosphate, urea phosphate, pyrophosphoric acid, and ammonium hypophosphite (AHP), were respectively added to the driving electrolyte of Example 2 above. A drive electrolytic solution to which 1.5 parts by weight was added was prepared, and an electrolytic capacitor using this was prepared. The product was allowed to stand at 105 ° C., and the rate of change in capacitance after 500 hours (ΔC) The loss angle tangent (tan δ) and leakage current (LC) were measured. The results are shown in (Table 5).

  As is clear from Table 5, it is understood that the characteristic change is small when monophosphoric acid is used as the additive of the phosphorus compound.

  As described above, the use of the driving electrolyte of the present invention provides a driving electrolyte that is stable and has a long life even under high temperature and high humidity, and also has good high-temperature reflow characteristics. Capacitors can be supplied.

  As described above, the electrolytic solution for driving an electrolytic capacitor according to the present invention is an electrolyte composed of an anion salt having a boron complex skeleton represented by (Chemical Formula 1) in an organic solvent and a cation salt having an amidine compound skeleton represented by (Chemical Formula 2). And at least boric acid as an additive, a driving electrolyte having high conductivity can be obtained, and hydrolysis of the boron complex is suppressed even under high temperature and high humidity. An electrolytic capacitor with stable characteristics can be obtained.

  The driving electrolyte according to the present invention has high conductivity and is stable even under high temperature and high humidity, and is useful as an electrolytic capacitor driving electrolyte and an electrolytic capacitor using the same.

Schematic of electrolytic capacitor in an embodiment of the present invention

Explanation of symbols

11 Internal element 12 Lead wire 14 Sealing body 15 Aluminum case

Claims (9)

The organic solvent contains an electrolyte composed of an anion salt having a boron complex skeleton represented by (Chemical Formula 1) and a cation salt of an amidine compound skeleton represented by (Chemical Formula 2), and at least boric acid as an additive. An electrolytic solution for driving an electrolytic capacitor.

The boron complex represented by (Chemical Formula 1) is borodisalicylic acid, borodiglycolic acid, borodisoxalic acid, borodimalonic acid, borodisuccinic acid, borodiadipic acid, borodimaleic acid, borodilactic acid, borodimalic acid, boroditartaric acid, borodicitric acid, borodiphthalic acid, borodiphthalic acid 2. The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the electrolytic solution is at least one selected from the group consisting of (2-hydroxy) isobutyric acid, borodimandelic acid and borodi (3-hydroxy) propionic acid. The electrolytic solution for driving an electrolytic capacitor according to claim 1 or 2, wherein the concentration of the electrolyte comprising the boron complex skeleton and the amidine compound skeleton is 10 to 50 parts by weight. The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the amount of boric acid added is 0.5 to 3 parts by weight. The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the additive contains at least one of a phosphorus compound and a polysaccharide. The electrolytic solution for driving an electrolytic capacitor according to claim 5, wherein the addition amount of the phosphorus compound is 0.5 to 2 parts by weight. The electrolytic solution for driving an electrolytic capacitor according to claim 5, wherein the amount of polysaccharide added is 0.5 to 2 parts by weight. 2. The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the organic solvent is mainly γ-butyrolactone, ethylene glycol, sulfolane, or a mixed solution thereof. An electrolytic capacitor using the electrolytic solution for driving an electrolytic capacitor according to claim 1.

Images