JPH0782965B2 - Electrolytic solution for driving electrolytic capacitors - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic capacitor, and more specifically to an electrolytic solution for driving an aluminum electrolytic capacitor.

2. Description of the Related Art Conventionally, as an electrolytic solution for driving an electrolytic capacitor, an electrolytic solution in which ionogen is dissolved in ethylene glycol has been used. This type of electrolytic capacitor deteriorates the characteristics at low temperatures. In order to improve the above drawbacks, JP-A-61
As disclosed in JP-A-70711, an example using γ-butyrolactone as a solvent and a triethylamine salt of phthalic acid, and, as seen in JP-A-54-7564, a mixed solvent of γ-butyrolactone and ethylene glycol. There is an example of using an amine salt of maleic acid.

Problems to be Solved by the Invention However, as a conventional problem, when γ-butyrolactone is used as a solvent and a triethylamine salt of phthalic acid is used,
It has a low specific conductivity and high stability at 105 ° C, but it is not very stable at 125 ° C.
Further, when an amine salt of maleic acid is used as a mixed solvent of γ-butyrolactone and ethylene glycol, the specific electric conductivity is sufficiently high, but the stability at high temperature is 105 ° C.
Above all, it has a drawback of low stability.

The present invention solves such conventional drawbacks, and an object thereof is to provide an electrolytic solution having high conductivity and little deterioration at high temperature, aiming at improvement of loss characteristics of an electrolytic capacitor and long life at high temperature. To do.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention dissolves a diazabicycloalkene salt of phthalic acid into a solute in a solvent mainly composed of γ-butyrolactone, and further alkylphosphoric acid. An electrolytic solution for driving an electrolytic capacitor, which uses an ester or a salt thereof and / or P-nitrobenzoic acid or a salt thereof as an additive.

Of the diazabicycloalkenes, preferably 1.8-diazabicyclo [5.4.0] undecene-7,1.5-diazabicyclo [4.3.0] nonene-5,1.8-diazabicyclo [5.3.
0] decene-7,1.4-diazabicyclo [3.3.0] octene-4,10-methyl-1.8-diazabicyclo [5.4.0] undecene-7,3-methyl-1.5-diazabicyclo [4.3.0] nonene-5 and It is a mixture of two or more of these, particularly preferably 1.8-diazabicyclo [5.4.0] undecene-
7 and 1.5-diazabicyclo [4.3.0] nonene-5.

Although the effect can be recognized by using any alkyl group of the alkyl phosphate ester, preferably, monoethyl phosphate ester, monopropyl phosphate ester, monobutyl phosphate ester, monopentyl phosphate ester,
Diethyl phosphate ester, dipropyl phosphate ester,
Dibutyl phosphate ester, dipentyl phosphate ester and salts thereof.

Action Diazabicycloalkenes have delocalized electrons not possessed by ordinary amines It has an amidine structure, and when it becomes an ion, it is considered that the proton is resonance-stabilized and exhibits strong basicity. Therefore, it is believed that the weak acid is promoted to dissociate and a high specific conductivity is obtained.

Further, since it has a cyclic structure, it is unlikely to decompose even at high temperatures and is considered to be stable for a long time.

Further, alkyl phosphate or P-nitrobenzoic acid is adsorbed on the surface of the aluminum electrode foil to protect the dielectric oxide film, thereby reducing the capacitance and increasing tan δ.
It is considered that the increase of the can be significantly suppressed.

Examples Hereinafter, examples according to the present invention will be described.

Table 1 shows examples of the present invention, conventional electrolytic solution composition examples, and specific electric conductivity at room temperature.

As is clear from Table 1, a higher specific electric conductivity can be obtained as compared with the conventional electrolytic solution.

Table 2 shows initial characteristics of capacitors using the electrolytic solutions of Conventional Example 1, Conventional Example 2, Example 1, Example 2, Example 3 and Example 6 of Table 1. Sample capacitor is 6.3V 1000μF
(Φ10 × 12.5) aluminum electrolytic capacitor.

As is clear from Table 2, the embodiment has a ta
nδ can be lowered.

FIGS. 1 to 3 show changes with time in characteristics of the aluminum electrolytic capacitors shown in Table 2 at 125 ° C. FIG. 1 is a diagram showing a change in capacitance when a rated voltage is applied, FIG. 2 is a diagram showing a tangent change in loss angle when a rated voltage is applied, and FIG. 3 is a diagram showing a leak current change when no voltage is applied.

As is apparent from FIGS. 1 to 3, the change in characteristics is extremely small even at high temperatures, and a highly reliable capacitor can be obtained.

EFFECTS OF THE INVENTION As described above, according to the present invention, loss characteristics can be improved as compared with conventional electrolytic solutions, and an extremely stable and highly reliable electrolytic capacitor can be provided even at a high temperature of 125 ° C. Is a great thing.

[Brief description of drawings]

FIGS. 1 to 3 show changes with time in characteristics of an aluminum electrolytic capacitor rated at 6.3V 1000 μF (φ10 × 12.5) using the conventional electrolytic solution and the electrolytic solution of the present invention at 125 ° C., respectively. FIG. 2 is a characteristic diagram showing a change in capacitance when a rated voltage is applied, FIG. 2 is a characteristic diagram showing a tangent change in loss angle when a rated voltage is applied, and FIG.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisao Nagata 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Keiji Mori, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor ▲ Yoshi ▼ Shingo Taba 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A solvent containing γ-butyrolactone as a main component,
Dissolve the phthalic acid salt of diazabicycloalkene as a solute to form an alkyl phosphate or its salt and / or
Alternatively, P-nitrobenzoic acid or a salt thereof is added to the electrolytic solution for driving an electrolytic capacitor. 2. The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the diazabicycloalkene is 1.8-diazabicyclo [5.4.0] undecene-7. 3. The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the diazabicycloalkene is 1.5-diazabicyclo [4.3.0] nonene-5. 4. The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the alkyl phosphate ester or salt thereof has a chemical structure such as A and B below.