JPH03126211A - Electrolyte for electrolytic capacitor - Google Patents

Abstract

PURPOSE:To improve voltage resistance by adding glycerin alkylether containing predetermined composition to electrolyte for an electrolytic capacitor containing organic polarizable solvent as main solvent and organic acid, inorganic acid or its salts as solute. CONSTITUTION:Glycerin alkylether represented by a formula is added to electrolyte for an electrolytic capacitor containing organic polarizable solvent as main solvent and organic acid, inorganic acid or its salts as solute. In the formula, Y1 to Y3 are the same or different -(R), -X, hydrogen atoms, higher alcohol residue, wherein at least one is higher alcohol residue, and the X in the -(R), -X is hydrogen atom, higher acyl group or higher alcohol residue, a is one or more integer numbers, R is ethylene oxide and/or propylene oxide. In the formula, a is suitably if in a range preferably from 1 to 100 since, if the polymerization becomes high, its synthesis becomes difficult or solubility is lowered.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to improving an electrolyte for electrolytic capacitors,
In particular, it relates to an electrolytic solution for electrolytic capacitors with improved voltage resistance.

[Conventional technology]

A typical electrolytic capacitor consists of an anode electrode foil with an insulating oxide film layer formed on the surface of a roughened valve metal foil such as aluminum or tantalum, and a cathode electrode foil for current collection using electrolytic paper. The capacitor element is formed by winding the capacitor element through the capacitor, impregnated with an electrolytic solution, and housed in an exterior case.

The oxide film layer formed on the anode electrode foil of the capacitor element serves as a dielectric, and the electrolyte solution serves as an electrolyte layer. The electrolytic solution, which is this electrolyte layer, acts as a true cathode. That is, the electrolytic solution is interposed between the dielectric layer formed on the anode foil and the cathode foil for current collection, and its resistance is inserted in series with the electrolytic capacitor.

Therefore, if the conductivity of the electrolytic solution is low, the equivalent series resistance inside the electrolytic capacitor will increase, which will adversely affect the high frequency characteristics and loss characteristics. However, when the conductivity of the electrolyte is improved during boat fishing, the spark voltage tends to decrease, and the withstand voltage characteristics of the electrolytic capacitor may be impaired. Conversely, when various additives are added to improve the withstand voltage characteristics, the electrical conductivity decreases, resulting in increased loss.

Therefore, as a means to improve the withstand voltage characteristics of an electrolytic capacitor without reducing its conductivity, it has been proposed to add various additives to the electrolytic solution.

For example, sulfamic acid (JP-A-49-82963)
, superric acid (JP-A-49-133860), dodecyl phosphate (JP-A-49-73659), alkyl phosphoric acid (JP-A-52-153154), diphosphorous acid (JP-A-57-141913) ), boric acid-mannitol system (JP-A-57-60829), boric acid-mannitol-polyvinyl alcohol system (JP-A-59-177915), modified silicone oil (JP-A-1-175722), etc. be.

[Problem to be solved by the invention]

However, as the scope of use of electronic devices increases, there is a growing demand for improvements in the performance of electrolytic capacitors, and the conductivity of conventional electrolytes is no longer sufficient. Therefore, it is necessary to further improve the conductivity of the electrolytic solution, and as a result, it becomes difficult to maintain voltage resistance characteristics.

An object of the present invention is to provide an electrolytic solution that maintains high electrical conductivity and has improved withstand voltage characteristics.

[Means to solve the problem]

General formula 2CH, -0-Y is used as an electrolytic solution for electrolytic capacitors with an organic polar solvent as the main solvent and an organic acid, an inorganic acid, or a salt thereof as a solute.

CH-0-Y.

C1,-0-Y.

(In the formula, Yl to Y3 are the same or different - + R) r X is a hydrogen atom or a higher alcohol residue; , a hydrogen atom, a higher acyl group, or a higher alcohol residue, a is an integer of 1 or more, and R represents ethylene oxide and/or propylene oxide).

Note that a in the above general formula is not particularly limited as long as it is 1 or more, but if the degree of polymerization becomes extremely high, disadvantages such as difficulty in synthesis and decreased solubility will occur.
Preferably, it is approximately 1 or more and 100 or less.

Specific examples of higher alcohols include hexyl alcohol, heptyl alcohol, octyl alcohol, caprylic alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, and heptadecyl alcohol. Decyl alcohol, stearyl alcohol, nonadecyl alcohol,
Examples include eicosyl alcohol, ceryl alcohol, mericyl alcohol, oleyl alcohol, and phytol.

In addition, as fatty acids corresponding to higher acyl groups, there are saturated fatty acids represented by the general formula: CL (CH2), 1COOH (n is an integer of 9 or more), such as undecylic acid (n = 9), lauric acid (n=10),
Tridecylic acid (n・11), myristic acid (n=12)
, pentadecylic acid (n=13), valmitic acid (n=1
4), heptadecylic acid (n・15), stearic acid (n
= 16), nonadecanoic acid (n 17), arachidic acid (n
= 18), behenic acid (n = 20), lignoceric acid (n
= 22), cerotic acid (n = 24), heptacanoic acid (
n・25), montanic acid (n=27), melisic acid (n
・28), rough cellic acid (n・30), etc.

In addition, as unsaturated fatty acids, undecylic acid <10> (1
1), oleic acid (cis) <9> (18), elaidic acid (trans) <9> (1B), cetoleic acid di> (22), erucic acid (sis) d3> (22)
, brassic acid (trans) <13> (22), linoleic acid <9.12> (1B), linuric acid <9.12.
15>(1B), arachidonic acid<5.8, 11.14
> (20), stearol acidic triple viscosity, 9 > (18
) [<> represents the position of an unsaturated bond, and () represents the total number of carbon atoms].

The organic polar solvent that is the main solvent of the electrolyte according to the present invention includes ethanol, propatool, protic polar solvent,
There are monohydric alcohols such as butanol and pentanol, polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, and methoxyethanol, and alcohol ethers. Examples of aprotic polar solvents include N-methylformamide, N, Examples include amide-based polar solvents such as N-dimethylformamide, N-ethylformamide, and N,N-diethylformamide, lactones such as T-butyrolactone, N-methyl-2-pyrrolidone, and ethylene carbonate, and cyclic amide-based solvents. In addition, nitriles such as a7tonitrile and oxides such as dimethyl sulfoxide can be exemplified as aprotic polar solvents.
These main solvents can be used alone or in combination.

Further, the electrolyte used in this invention is not particularly limited, and any commonly used electrolyte may be used. For example, anion sources include organic acids such as aliphatic monocarboxylic acids such as formic acid and acetic acid, aliphatic dicarboxylic acids such as malonic acid and succinic acid, and aromatic carboxylic acids such as benzoic acid and phthalic acid. , boric acid, phosphoric acid, silicic acid, etc. Examples of cation sources include monoalkylammonium cations such as ammonium and methylammonium, dialkylammonium cations such as dimethylammonium and diethylammonium, trialkylammonium cations such as trimethylammonium and triethylammonium, tetramethylammonium, and triethylmethylammonium. There are quaternary ammonium cations such as phosphonium and arsonium cations.

The electrolytic solution for an electrolytic capacitor according to the present invention is prepared by preparing 100 parts by weight of one or more of the above-mentioned organic polar solvents, and adding a solute consisting of an electrolyte substance in a solvent mixed with 0 to 30 parts by weight of water as needed. What is necessary is just to melt|dissolve 1-50 weight part individually or in combination of several. Desired characteristics can be obtained by adding preferably 0.1 to 20 parts by weight, more preferably 0.5 to 6 parts by weight of the glycerin alkyl (alkenyl) ether to such an electrolytic solution. can.

[Function] The effect of improving the withstand voltage characteristics of the glycerin alkyl (alkenyl) ether used in this invention is to add glycerin alkyl (alkenyl) ether as a nonionic surfactant to the interface of the aluminum oxide film, which is the dielectric of the electrolytic capacitor. ) It is thought that the formation of an ether micelle layer is involved.

〔Example〕

Examples of the electrolytic solution for electrolytic capacitors according to the present invention will be described below.

In each example, an electrolytic solution was prepared using the same solvent and solute as in the conventional example, and glycerin alkyl (alkenyl) ether was added thereto. The following glycerin alkyl (alkenyl) ethers were used.

A) Dibolyoxyethylene (POE・60) Glycerin monostearyl ether B) Cypolyoxyethylene (POE・20) Polyoxyethylene (POP=1
0) Glycerin alkyl ether) [sum of p to q = 20/s to sum of t = 10]
C) Sigilyoxybrobylene monolaurate (PO
P・30) Glycerin cetyl ether [sum of p to q = 30] D) Monopolyoxyethylene (POE = 20) Glycerin cytidyl ether CJ-OCHz-←C1,→7
CH:IC)I OCHz-fCHg→7”C
H5C1lz O+C1l□CH, O→7fC112
-←CH,→] "C113E) Glycerin monooleyl ether CH20CHz-(-CHI±rCH=CH-(-CH
zsuw-CH3l -OH CHz-OH [Total sum of P to q = 60] 1 large 1 l A) Dipolyoxyethylene (POE, 60) glycerin monostearyl ether and 1 yen) Dipoly Oxyethylene (POE=60) Glycerin monostearyl ether C) Dipolyoxypropylene monolaurate (POP=30) Glycerin cetyl ether [Takumi Godai JJL YuC] Dipolyoxypropylene monolaurate (POP=
30) Glycerin Cetyl Ether D) Monopolyoxyethylene (POE-20) Glycerin Didecyl Ether Large 11 Good L Large J011 D) Monopolyoxyethylene (POE=20) Glycerin Didecyl Ether E) Chrycerin Monooleyl Ether Based on the above results As can be seen, although the electrical conductivity of the electrolytic solution of the present invention tends to be the same or slightly lower than that of the conventional example, the withstand voltage was able to be improved by about 10% to 50%.

〔Effect of the invention〕

As described above, this invention uses an organic polar solvent as the main solvent,
General 2: CH, -0-Y for electrolytic solutions for electrolytic capacitors containing organic acids, inorganic acids, or their salts as solutes.

CHOY2 CH2-0-Yff (wherein, Y, to Y, are each the same or different -+ Rh-X, a hydrogen atom or a higher alcohol residue, at least one is a higher alcohol residue, and - (X in RhX is a hydrogen atom, a higher acyl group, or a higher alcohol residue, a is an integer of 1 or more, and R represents ethylene oxide and/or propylene oxide). By adding a small amount of these additives to a normal electrolytic solution, it is possible to improve the withstand voltage characteristics while maintaining the electrical conductivity.

Therefore, the electrical characteristics at high voltage are well stabilized,
The reliability of electrolytic capacitors using this electrolyte is improved.

Claims (1)

[Claims] (1) The electrolytic solution for electrolytic capacitors has an organic polar solvent as the main solvent and an organic acid, an inorganic acid, or a salt thereof as a solute, and has a general formula: ▲Mathematical formula, chemical formula, table, etc.▼ (In the formula, Y_1 to Y_3 are the same or different -(R)_a-X, a hydrogen atom or a higher alcohol residue, and at least one is a higher alcohol residue, and X in -(R)_a-X is a hydrogen atom, It is a higher acyl group or higher alcohol residue,
a represents an integer of 1 or more, and R represents ethylene oxide and/or propylene oxide. An electrolytic solution for electrolytic capacitors characterized by adding glycerin alkyl (alkenyl) ether of ).