JPH11145004A - Electrolyte for driving electrolytic capacitor and electrolytic capacitor for storage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolyte for driving electrolytic capacitor having high electric conductivity and, at the same time, to provide an inexpensive electrolytic capacitor for strobe having low tanδ and a stable leakage current characteristic by using the electrolyte in the electrolytic capacitor for strobe. SOLUTION: An electrolyte is prepared by dissolving one or more kinds of solutes selected from azelaic acid, adipic acid, benzoic acid, and their ammonium salts in a solvent composed mainly of ethylene glycol and adding 10-25 wt.% water and organic phosphate to the solution, so that the electric conductivity of the electrolyte may become >=4 mS/cm. Then an inexpensive electrolytic capacitor for strobe is obtained by impregnating the capacitor element 4 of the capacitor with the electrolyte for driving electrolytic capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic solution for driving an electrolytic capacitor and a strobe electrolytic capacitor using the same.

[0002]

^2. Description of the Related Art Usually, the voltage of a strobe electrolytic capacitor used in a strobe device greatly depends on the voltage due to the storage energy represented by 1 / 2.times.C.times.V.sub.2. 330V is mainly used due to its price.

[0003] The electrolytic solution for driving the electrolytic capacitor used for the strobe electrolytic capacitor usually contains an organic compound such as ethylene glycol as a main solvent and an inorganic acid such as boric acid, adipic acid, azelaic acid, sebacic acid or the like. An electrolytic solution for driving an electrolytic capacitor in which a solute composed of the above-mentioned dibasic acids and salts thereof is dissolved is used. Since the solute in the electrolytic solution for driving the electrolytic capacitor is dissolved in a solvent such as ethylene glycol at an appropriate concentration,
Chemical conversion and electric conductivity can be controlled relatively easily.

[0004]

The above electrolytic solution for driving an electrolytic capacitor has an electric conductivity of about 4 mS / cm even at the upper limit, but at this electric conductivity, the discharge voltage of the electrolytic solution for driving the electrolytic capacitor is extremely reduced. Thus, an electrolytic capacitor could not be manufactured, and at this conductivity level, it was not expected that tan δ of the electrolytic capacitor was significantly reduced.

In order to improve the degree of dissociation, there is also a means for increasing the conductivity by adding an excessive amount of water. In this case, however, the electrode foil used in the electrolytic capacitor is affected by the effect of the excessively added water. There is a problem that the hydration is deteriorated, and as a result, the voltage rise time, which is an important characteristic of the electrolytic capacitor for a strobe, is remarkably deteriorated.

[0006] In addition to the above-described problems in terms of characteristics, there is also a problem of cost reduction due to a high cost component ratio of the electrolytic capacitor in the flash device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. An object of the present invention is to provide an electrolytic solution for driving an electrolytic capacitor having high conductivity, and to use the electrolytic solution for a strobe electrolytic capacitor. Accordingly, it is an object of the present invention to provide an inexpensive strobe electrolytic capacitor having low tan δ, stable leakage current and stable charging characteristics.

[0008]

In order to achieve the above object, the electrolytic solution for driving an electrolytic capacitor of the present invention is prepared by adding a solvent mainly composed of ethylene glycol to azelaic acid, adipic acid, benzoic acid or an ammonium salt thereof. One or more solutes, 10 to 25 wt% of water and an organic phosphate are added and dissolved, and the conductivity is set to 4 mS / cm.
As described above, according to this configuration, it is possible to obtain an electrolytic solution for driving an electrolytic capacitor having high conductivity, and it is possible to obtain a low ta
It is possible to obtain a strobe electrolytic capacitor having a stable leakage current and charging characteristics at nδ.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is characterized in that a solvent mainly composed of ethylene glycol is mixed with a solute of at least one of azelaic acid, adipic acid, benzoic acid or an ammonium salt thereof, 10 to 25 wt% of water and an organic phosphoric acid ester are added and dissolved to make the electric conductivity 4 mS / cm or more. According to this configuration, the electric conductivity of the electrolytic solution for driving the electrolytic capacitor can be sufficiently drawn. Thus, it is possible to obtain an electrolytic solution for driving an electrolytic capacitor having a good chemical conversion property and a high discharge voltage.

According to a second aspect of the present invention, the amount of the organic phosphoric acid ester is in the range of 0.3 to 10% by weight.
According to this configuration, the addition amount of the organic phosphate is set to 0.3
Water content of 10 to 25 wt%
Even with the electrolytic solution for driving an electrolytic capacitor containing wt%, it is possible to suppress the hydration deterioration of the aluminum foil used for the electrolytic capacitor.

According to a third aspect of the present invention, there is provided a solvent mainly composed of ethylene glycol, a solute of at least one of azelaic acid, adipic acid, benzoic acid or an ammonium salt thereof, and 10 to 25 wt% of water. An organic phosphoric acid ester was added and dissolved, and the electrolytic solution was configured using an electrolytic solution for driving an electrolytic capacitor having an electric conductivity of 4 mS / cm or more. By using the electrolytic solution for driving an electrolytic capacitor, tan δ was reduced. It is possible to obtain a strobe electrolytic capacitor having low and stable withstand voltage characteristics.

According to a fourth aspect of the present invention, the rated voltage is 23
0 to 330 V and tan δ of 4% or less. According to this configuration, the rated voltage is 230 to 33 V.
Since the voltage is set in the range of 0 V, the luminous efficiency of a strobe device using this strobe electrolytic capacitor can be improved, and the capacity of the strobe electrolytic capacitor can be reduced. Can be obtained.

Hereinafter, embodiments of the present invention will be described. In general, a strobe device equipped with a strobe electrolytic capacitor charges an electrolytic capacitor to about 330 V with a power supply or the like, and discharges the charged electric charge instantaneously through a flash discharge tube to emit light. When the relationship between the luminous efficiency and the charging voltage was measured in order to investigate the validity of the charging voltage set to 330 V, it was found that the optimal voltage band of the luminous efficiency was around 250 V as shown in FIG. . In other words, in this voltage band, 33
The luminous efficiency is improved by about 10% as compared with 0V.

This is because artificial light emitted from a strobe device has a useful wavelength distribution in the vicinity of visible light, but other wavelengths, such as infrared light and ultraviolet light, are not suitable for photographing light. It is well known that it is unnecessary, and it is considered that the luminous efficiency is improved in the voltage band around 250 V by reducing the generation of wavelength light such as ultraviolet light and infrared light.

Generally, an electrolytic capacitor for a strobe is shown in FIG.
As shown in FIG. 1, the capacitor element 4 is wound by winding an anode foil 1 as an anode electrode made of aluminum and a cathode foil 2 as a cathode electrode also made of aluminum so as to face each other with a separator 3 interposed therebetween. Make up. Lead wires 5 and 6 are connected to the anode foil 1 and the cathode foil 2 constituting the capacitor element 4, respectively. After the capacitor element 4 having such a configuration is impregnated with the driving electrolyte, the capacitor element 4 is inserted into the bottomed cylindrical outer case 7 made of aluminum.
In addition, the opening of the outer case 7 is sealed with a rubber sealing body 8.

The cost ratio of each component of the strobe electrolytic capacitor is 50% or more of the electrode foil. If the use amount of the electrode foil can be reduced, the cost of the strobe electrolytic capacitor can be reduced.

Therefore, an improvement in efficiency when the strobe electrolytic capacitor is changed from 330 V to 250 V will be calculated below.

When a strobe electrolytic capacitor having a rating of 330 V and 120 μF is set to 250 V, in order to obtain the same amount of light, 209 μF is required in the relation of stored energy = １ ／ × C × V ² . However, since the luminous efficiency can be improved by 10% as described above, the same amount of light can be obtained even if the capacitance is reduced to 188 μF (10% reduction).

Further, the present inventors have studied the loss of charging energy due to self-heating caused by the resistance of the strobe electrolytic capacitor itself during discharging. As a result, the tan δ of the strobe electrolytic capacitor was 4%. From this, it was found that the luminous efficiency could be reduced by about 12% by setting it to 2%, for example. This result indicates that the capacity of the above 250 V strobe electrolytic capacitor can be further reduced by 12%. That is, the voltage range is set to 250
By improving the luminous efficiency and reducing tan δ by setting V, the capacity of the strobe electrolytic capacitor required by the storage energy = １ ／ × C × V ² can be reduced by about 20%. As a result, the area of the electrode foil constituting the capacitor element 4 of the strobe electrolytic capacitor can be reduced, so that a small-sized and low-cost strobe electrolytic capacitor can be obtained.

FIG. 3 shows the results of the above-mentioned examination.
Capacity and light quantity (guide No.) of 50V strobe electrolytic capacitor and tan δ of strobe electrolytic capacitor
Is shown.

As apparent from the above description, 250 V
A strobe electrolytic capacitor used in a strobe device that emits light in a nearby voltage band is required to have a low tan δ. In order to realize the low tan δ, the electrolytic solution for driving an electrolytic capacitor having high conductivity as shown in the present invention is required.

Next, the basic characteristics of the solute constituting the electrolytic solution for driving the electrolytic capacitor of the present invention will be described below.

In the present invention, attention has been paid to the addition of water in order to improve the electric conductivity of the electrolytic solution for driving the electrolytic capacitor. FIG. 4 shows the water addition characteristics of the solute used in the present invention.
FIG. 4 shows that a solute composed of ammonium adipate, ammonium azelate, and ammonium benzoate was added to 0.1% solute.
FIG. 4 shows the conductivity characteristics when the water content was changed by dissolving in a solvent consisting of 5 mol / l ethylene glycol and water. In FIG. 4, only the solute concentration of 0.5 mol / l is shown. Although not shown, when the solute concentration is increased, the conductivity is increased in proportion to the increase. However, since these solutes have respective limits in solubility, it is desirable to dissolve them in a range of 2 mol / l or less.

As shown in FIG. 4, the reason that ammonium benzoate has a lower conductivity than ammonium adipate and ammonium azelate is because it is a monobasic acid, but the water content increases in any solute. According to this, the electrolytic solution for driving the electrolytic capacitor can obtain high conductivity.

FIG. 5 shows the results of a study on the tan δ of a strobe electrolytic capacitor when a strobe electrolytic capacitor is manufactured using the electrolytic solution for driving an electrolytic capacitor having high conductivity.

As shown in FIG. 5, the relationship between the tan δ of the strobe electrolytic capacitor and the conductivity of the electrolytic solution for driving the electrolytic capacitor has a downward-sloping curve relationship. That is, the tan of the strobe electrolytic capacitor exceeds a certain value.
This indicates that a drastic improvement in electrical conductivity is required to reduce δ.

Referring to FIG. 3, when the tan δ of the 250 V strobe electrolytic capacitor capable of improving the luminous efficiency is defined, it is set to 4% or less in consideration that the usual value of the conventional 330 V product is about 4 to 5.5%. It turns out that it becomes effective by doing. Therefore, in order to reduce the tan δ of the product to 4% or less from FIG. 5, the conductivity of the electrolytic solution for driving the electrolytic capacitor needs to be 3 mS / cm or more. In consideration of a margin, in the present invention, the electric conductivity of the electrolytic solution for driving the electrolytic capacitor is determined to be 4 mS / cm or more. The higher the conductivity of the electrolytic solution for driving the electrolytic capacitor, the lower the tan δ of the strobe electrolytic capacitor and the higher the luminous efficiency of the strobe. Naturally, even if the voltage of the strobe electrolytic capacitor is 330 V, the capacity of the strobe electrolytic capacitor can be reduced by reducing tan δ. Therefore, the effect can be obtained even if the strobe electrolytic capacitor is rated at 330 V. Therefore, the upper limit of the rating of the strobe electrolytic capacitor is set to 330V.

Further, in consideration of the variation in the etching magnification of the anode foil, in the present invention, when the conductivity of the electrolytic solution for driving the electrolytic capacitor is 4 mS / cm or more, as shown in FIG. The lower limit of the amount can be specified to be 10%. However, if the water content of the electrolytic solution for driving the electrolytic capacitor exceeds 25%, the hydration deterioration of the electrode foil cannot be suppressed, so the upper limit is set to 25%.

Next, a specific embodiment of the present invention will be described. The compositions and characteristics of the electrolytic solutions for driving electrolytic capacitors according to Embodiments 1 to 7 of the present invention and Conventional Examples 1 to 3 are shown in (Table 1).

[0030]

[Table 1]

As is clear from Table 1 and FIG. 4, the electrolytic solutions for driving the electrolytic capacitors according to Embodiments 1 to 7 of the present invention have a sufficient amount of water added thereto, and thus the conventional electrolytic capacitors 1 and 2 are not used.
The electric conductivity can be remarkably improved as compared with the electrolytic solution for driving the electrolytic capacitor of No. 2.

The electrolytic solution for driving the electrolytic capacitor according to Embodiments 1 to 7 of the present invention is prepared by adding a solvent mainly containing ethylene glycol, which is an organic compound, to any one of azelaic acid, adipic acid, benzoic acid or an ammonium salt thereof. High conductivity is obtained by adding and dissolving at least 10 kinds of solutes, 10 to 25 wt% of water and an organic phosphate.

Although the addition of water increases the degree of dissociation of the organic acid, it can be expected that the conductivity will be further improved. This causes an increase in leakage current and deterioration of charge / discharge characteristics. In order to prevent the hydration deterioration, an organic phosphate is added. Organic phosphate esters
Since it has an action of protecting the surface by being adsorbed to the electrode foil, hydration deterioration can be prevented. By implementing the above measures, a strobe electrolytic capacitor having a low tan δ and a stable leakage current and charging characteristics can be obtained.

A strobe electrolytic capacitor of the present invention using the electrolytic solution for driving an electrolytic capacitor of high conductivity and a strobe electrolytic capacitor of the prior art using the electrolytic solution for driving an electrolytic capacitor were prepared for each of 20 pieces. (Table 2) shows the results of the above. The strobe electrolytic capacitors used here have a rating of 250 WV 160 μF
And the test temperature was 85 ° C.

[0035]

[Table 2]

As is apparent from Table 2, the strobe electrolytic capacitors using the electrolytic solution for driving the electrolytic capacitors according to the first to seventh embodiments of the present invention have low tan δ and stable leakage current characteristics. Things.

Here, in Conventional Example 3, although the electrolytic solution for driving the electrolytic capacitor in which the water content is set to the water content of the present invention is used, since orthophosphoric acid which is an inorganic phosphoric acid is used,
Leakage current and voltage rise time deteriorate and are not at a usable level. In Embodiments 1 to 7 of the present invention, it can be determined that hydration deterioration can be suppressed because an organic phosphate is used.

In the embodiment of (Table 1), only about four kinds of organic phosphoric acid esters of 1, 2, 3, and 6 are listed as the organic phosphoric acid ester in the present invention. Is effective, and the above effect can be obtained by adding and dissolving one or more kinds.

[0039]

Embedded image

R ₁ , R ₂ and R ₃ represent -H or an alkyl group. However, R ₁ , R ₂ and R ₃ are not simultaneously -H.

These organic acid esters have a slightly different effect of suppressing hydration deterioration of the electrode foil due to the difference in structure.
Generally, the addition amount of 0.3 to 10% by weight is effective, and if the addition amount is small, the effect is not sufficient, and if the addition amount is excessive, the dissolving action of the electrode foil is dominant in the electrolytic capacitor for strobe light. Therefore, the probability of causing a short circuit or the like of the electrolytic capacitor for a strobe is increased.

[0042]

As described above, the electrolytic solution for driving an electrolytic capacitor of the present invention is prepared by mixing a solvent mainly composed of ethylene glycol with a solute of at least one of azelaic acid, adipic acid, benzoic acid or an ammonium salt thereof. , 10-2
5 wt% of water and an organic phosphoric acid ester are added and dissolved to make the electric conductivity 4 mS / cm or more. According to this configuration, the electric conductivity of the electrolytic solution for driving the electrolytic capacitor can be sufficiently drawn out. In addition, it is possible to obtain an electrolytic solution for driving an electrolytic capacitor having a good chemical conversion property and a high discharge voltage.
An electrolytic capacitor for strobe with stable leakage current and charging characteristics at an δ can be obtained.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing a correlation between a charging voltage of a strobe electrolytic capacitor and a luminous efficiency of a strobe device.

FIG. 2 is a cutaway perspective view of a strobe electrolytic capacitor.

FIG. 3 is a characteristic diagram showing the correlation between the capacity of a 250 V strobe electrolytic capacitor and the light amount (guide No.) and the tan δ of the strobe electrolytic capacitor.

FIG. 4 shows conductivity characteristics when a solute composed of ammonium adipate, ammonium azelate, and ammonium benzoate is dissolved in a solvent composed of 0.5 mol / l ethylene glycol and water to change the water content. Characteristic diagram

FIG. 5 is a characteristic diagram showing a correlation between the conductivity of an electrolytic solution for driving an electrolytic capacitor and tan δ of a strobe electrolytic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode foil 2 Cathode foil 3 Separator 4 Capacitor element 5, 6 Lead wire 7 Outer case 8 Sealing body

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Ozaki 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A solvent mainly composed of ethylene glycol and a solute of at least one of azelaic acid, adipic acid, benzoic acid or an ammonium salt thereof,
An electrolytic solution for driving an electrolytic capacitor, in which 5 wt% of water and an organic phosphate are added and dissolved, and the electric conductivity of which is 4 mS / cm or more. 2. The amount of the organic phosphoric acid ester added is from 0.3 to 1
The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the electrolytic solution is in a range of 0 wt%. 3. A solvent mainly composed of ethylene glycol and a solute of at least one of azelaic acid, adipic acid, benzoic acid or an ammonium salt thereof,
An electrolytic capacitor for a strobe constituted by using an electrolytic solution for driving an electrolytic capacitor having an electric conductivity of 4 mS / cm or more by adding and dissolving 5 wt% of water and an organic phosphate. 4. The strobe electrolytic capacitor according to claim 3, wherein the rated voltage is in the range of 230 to 330 V and tan δ is 4% or less.