JPH05315196A - Method of connecting dielectrics to ion conductive polymer composition - Google Patents

Abstract

PURPOSE:To enhance the long-term reliability and characteristics in an electrical chemical element such as an electrolytic capacitor, etc., by a method wherein an ion conductive polymer composition constituting a polymer electrolyte layer is dropped or sprayed from above of the dielectric electrode surface. CONSTITUTION:Primary liquid of an ion conductive polymer composition is made by a method wherein a chemical compound, ammonium boro-disalicylate, diethylene glycol, further methylethyl ketone as a solvent for diluting are stirred and mixed. Successively, by using an applier, an ion conductive polymer composition layer 5 is connected to the anode 2. The applier is used with a nozzle and nitrogen pressure is applied and the primary liquid of the ion conductive polymer composition is applied to the dielectric surface of the cathode 2 from the vertical direction. Thus, it is possible to obtain an electrical chemical element such as an electrolytic capacitor, etc., which is excellent in low impedance, high capacitance, and a long life.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining a dielectric and an electrolyte in an electrochemical device, such as an electrolytic capacitor, which is constructed by joining a dielectric and an electrolyte.

[0002]

2. Description of the Related Art Conventionally, in the construction of electrolytic capacitors, oxides such as aluminum oxide have been used as dielectrics, and organic electrolytes prepared by dissolving ammonium salts in high boiling organic solvents such as ethylene glycol have been used as electrolytes. However, a capacitor using such an electrolytic solution cannot obtain long-term reliability due to leakage or evaporation of the electrolytic solution.

In order to solve such a problem, instead of the electrolytic solution constituting the capacitor, a polymer composed of a mixture of siloxane-alkylene oxide copolymer and polyethylene oxide is used as a base material, and an alkali metal salt is dissolved in the polymer to carry out ion conduction. There is proposed an electrolytic capacitor (Japanese Patent Laid-Open No. 1-503425) in which the element is solidified by using a conductive polymer electrolyte and leakage or evaporation of the electrolytic solution is prevented.

However, in an electrolytic capacitor using an ion conductive polymer electrolyte having an alkali metal as a mobile ion as an electrolyte, the alkali metal ion diffuses into the dielectric material constituting the electrolytic capacitor, which causes the dielectric constant of the dielectric material. However, there was a problem in that it eventually decreased and eventually short circuited electrically.

In order to solve such a problem, it is conceivable to use ammonium ions as the mobile ions constituting the polymer electrolyte.

However, it has been conventionally known that ion conductive polymer electrolytes in which ammonium salts are dissolved generally have extremely low ionic conductivity (conductive polymer Naoya Ogata, Kodansha Scientific 1990).
Year).

Further, the ionic conductivity of the electrolyte constituting the electrolytic capacitor acts as an impedance as a capacitor, and if the ionic conductivity of the electrolyte is too small, it is practically difficult to use.

When such an ion conductive polymer electrolyte is used as an electrolyte of an electrolytic capacitor, how to achieve high ion conductivity by combining a polymer matrix and an ammonium salt is a very important requirement. However, this specific example is not described in the electrolytic capacitor described in Japanese Patent Laid-Open No. 1-503425.

At present, aluminum oxide is widely used as a dielectric material for electrolytic capacitors. In an actual configuration, by immersing a metal aluminum electrode whose surface is etched in a weakly acidic electrolytic solution and anodizing it electrochemically, aluminum oxide in a micropore state of about several hundred angstroms is created. The surface area is being improved.

In general, a method of joining a dielectric electrode and an electrolyte in an electrolytic capacitor using a liquid electrolyte is generally 0.05 mm in thickness using an electrically insulating material such as Manila hemp and the aperture ratio is 30%. It is carried out by vacuum impregnating a porous separator of a certain degree and pressing it onto the dielectric layer.

[0011]

However, when a polymer electrolyte is used as the electrolyte, its conductivity is lower than that of liquid electrolytes which are currently known. Therefore, when the above-mentioned separator is used as it is, the impedance as an element is extremely high. It had the problem of increasing to. Also, when the polymer electrolyte is impregnated in the porous separator, it is pressure-bonded to the dielectric electrode, and when the electrolyte is cured by heat treatment, the polyelectrolyte stock solution in contact with the dielectric micropores is absorbed by the porous part of the separator. As a result, there is a problem that the junction area between the electrolyte layer and the dielectric electrode is extremely reduced, and the positive capacitance as an element is reduced. At the same time, as a result, it is easily conceivable that the junction between the electrolyte layer and the dielectric electrode gradually peels off when the charge / discharge cycle is repeated.

That is, in the electrolytic capacitor using the polymer electrolyte as a constituent element, the cell impedance is lowered by making the thickness of the electrolyte layer as thin as possible, and the electrolyte and the dielectric are spread over a wide area. A method of joining while maintaining a strong joining force is a manufacturing problem.

[0013]

In order to solve such a problem, in the bonding of the present invention, the ion conductive polymer composition material constituting the polymer electrolyte layer is applied by dropping or spraying from above the dielectric electrode surface. By doing.

[0014]

According to the bonding method of the present invention, for example, using the ion conductive polymer composition material described in claims 4 and 5, the ion conductive polymer composition raw material is a dielectric composed of aluminum oxide in a micropore state. It can be penetrated into the body electrode, and by controlling the coating amount per hour, it is possible to realize electrostatic capacity and impedance characteristics that are practically equivalent to or higher than those of capacitors currently composed of liquid electrolytes. it can.

Further, the effect of the bonding method of the present invention can be enhanced by using a material stock solution of the ion conductive polymer composition applied to the dielectric electrode, which is previously diluted with a low viscosity solvent.

Further, the method for applying the ion conductive polymer composition to the dielectric electrode includes the distance between the ion conductive polymer composition and the dielectric electrode and the amount of the ion conductive polymer composition applied per hour. While maintaining the constant, by moving the dielectric electrode in parallel to the electrode surface, and by making the film thickness of the ion conductive polymer composition layer constant, it is possible to improve the efficiency of device production. ..

[0017]

EXAMPLES Specific examples of aluminum electrolytic capacitors prepared by the joining method of the present invention, which comprises the ion-conductive polymer composition described in claims 4 and 5 as constituent elements, will be described in detail below.

(Embodiment 1) FIG. 1 is a sectional view showing the construction of an aluminum electrolytic capacitor produced by the joining method of the present invention.
The anode connector 1 is spot-welded to one side of an electrode made of an aluminum foil having a thickness of 0.05 mm, a diameter of an etching hole of about 1 to 5 μm, and a size of 3 cm × 100 cm. Next, this is immersed in an aqueous boric acid solution (concentration: 80 g / l) kept at a temperature of 90 ° C., and the aluminum surface is oxidized at a current of 30 A for 15 minutes to obtain a dielectric material composed of aluminum oxide. The anode 2 was created by forming layers.

Further, the thickness is 0.05 mm, the diameter of the etching hole is about 1 to 5 μm, and the size is 2.8 cm × 100.
A cathode 4 was prepared by spot-welding the cathode connector 3 to one side of an electrode made of a cm aluminum foil. ..

Next, in the structural formula (Formula 2), (l +
m) × n = 50, the polymer compound (44 g), ammonium borodisalicylate (5.2 g), diethylene glycol (1.75 g), and methyl ethyl ketone (150 ml) as a diluting solvent are mixed by stirring.
A stock solution of the ion conductive polymer composition was prepared.

[0021]

[Chemical 2]

Subsequently, the ion-conducting polymer composition layer 5 was bonded to the anode 2 using the coating apparatus outlined in FIG. The coating apparatus shown in FIG. 2 uses a nozzle having a liquid hole diameter of 0.5 mm and a nitrogen pressure of 3 kg / cm 2 and a pressure of 1 l / h.
r. The above-mentioned stock solution of the ion conductive polymer composition is applied in a direction perpendicular to the dielectric surface of the anode 2. The coating method is such that the nozzle is 10 cm in the vertical direction of the anode 2.
Was fixed at a height of 10 cm / sec, the anode 2 was laterally run at a constant speed of 10 cm / sec, and coating was carried out at a nozzle blowing angle of 22 degrees.

The stock solution of the ion-conductive polymer composition applied in this manner had a thickness of 0.06 mm and a difference within 20%. After removing the methyl ethyl ketone contained in the stock solution by leaving it in the air at 90 ° C. for 1 hour,
The cathode 4 was pressure-bonded to the electrolyte surface so as to face it, and this was left in air at 90 ° C. for 3 hours to form a dielectric layer / ion-conductive polymer composition layer / cathode.

Finally, this is wound into a roll, stored in an aluminum tube 6, and a sealing agent 7 made of a silicone resin.
After injecting, the connector portion was sealed with epoxy resin 8 to produce an aluminum electrolytic capacitor A according to the manufacturing method of this embodiment.

As a comparative example, an aluminum electrolytic capacitor B using a conventionally known electrically insulating separator was prepared.

In the aluminum electrolytic capacitor B, the same components as the anode, the ion conductive polymer composition stock solution and the cathode were the same as those of the capacitor A. The ion-conductive polymer composition layer is formed by pouring the ion-conductive polymer composition stock solution into Manila hemp with a porosity of 30% and a thickness of 0.
After impregnating a separator having a size of 05 mm and a size of 3.1 cm × 102 cm under a reduced pressure of 1 Torr at room temperature, the dielectric surface of the anode and the aluminum surface 4 of the cathode were pressure-bonded to each other, and wound into a roll. After that, it was performed by storing at a temperature of 90 ° C. for 3 hours.

In this comparative example, the charged amount of methyl ethyl ketone, which is a solvent for diluting the stock solution of the ion conductive polymer composition, was 50 CC. This is because the minimum amount necessary for impregnating the separator having the above-mentioned shape is set.

As described above, the aluminum electrolytic capacitors A and B prepared by the two different manufacturing methods, the frequency characteristics of impedance and capacitance, and the cycle life characteristics of charging and discharging were evaluated. The results are shown in FIGS.
And described in FIG.

In FIG. 3, the vertical axis and the horizontal axis represent impedance and measurement frequency, respectively. From this evaluation, it was found that the impedance of the aluminum electrolytic capacitor B of the comparative example prepared by using the conventionally known separator is much higher than that of the aluminum electrolytic capacitor A prepared by the manufacturing method of the example.

In FIG. 4, the vertical axis and the horizontal axis represent capacitance and measurement frequency, respectively. From this evaluation, it was found that the impedance of the aluminum electrolytic capacitor B was extremely smaller than that of the aluminum electrolytic capacitor A.

From the above results, the manufacturing method according to the present invention is an extremely useful method for manufacturing an electrolytic capacitor using an ion conductive polymer composition for lowering impedance and increasing capacitance. I found out.

Further, in FIG. 5, the vertical axis represents the relative value with respect to the initial discharge capacity, and the horizontal axis represents the number of charge / discharge cycles.
The discharge capacity of electrolytic capacitors A and B is 1 at 500V.
It was evaluated by measuring the amount of electricity flowing when short-circuited for 5 minutes after charging for 0 minutes.

From these results, the electrolytic capacitor B of the comparative example
Shows a large capacity deterioration from about 1000 cycles, while the electrolytic capacitor A of the embodiment is 10,000
It was found that the initial performance was maintained even in the cycle.

In this embodiment, the example using ammonium borodisalicylate and methyl ethyl ketone as the material for forming the electrolyte layer is described, but the production method of the present invention is not particularly limited to this material. It has been found that the same effects can be obtained by using the materials described in claims 4 and 5.

[0035]

According to the present invention, it is possible to obtain an electrochemical device such as an electrolytic capacitor which has a low impedance, a high capacity, and a long life.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an electrolytic capacitor produced by a joining method according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a manufacturing apparatus according to a joining method according to an embodiment of the present invention.

FIG. 3 is a frequency-impedance characteristic diagram of the electrolytic capacitor according to the embodiment.

FIG. 4 is a frequency-capacitance characteristic diagram of the electrolytic capacitor according to the embodiment.

FIG. 5 shows the number of cycles of the electrolytic capacitor according to the same example.
Capacitance characteristic diagram

[Explanation of symbols]

 1 Anode Connector 2 Anode 3 Cathode Connector 4 Cathode 5 Ion Conductive Polymer Composition Layer 6 Aluminum Tube 7 Sealant 8 Epoxy Resin

Claims (5)

[Claims] 1. An electrochemical device comprising an ion conductive polymer composition layer bonded to an electrode made of a porous dielectric,
A dielectric and an ion-conductive polymer composition characterized in that the ion-conductive polymer composition material constituting the ion-conductive polymer composition layer is applied by dropping or spraying from above the dielectric electrode surface. Joining method. 2. The material stock solution of the ion conductive polymer composition applied to the dielectric electrode is diluted with a solvent that dissolves the ion conductive polymer composition material. 2. A method for joining the dielectric and the ion conductive polymer composition according to 1. 3. The coating of the ion conductive polymer composition on the dielectric electrode is performed by setting the distance between the ion conductive polymer composition and the dielectric electrode and the coating amount of the ion conductive polymer composition per hour. 3. The film thickness of the ion conductive polymer composition layer is made constant by moving the dielectric electrode at a constant speed while keeping it constant.
A method for joining the dielectric and the ion-conductive polymer composition as described. 4. A crosslinked body of a polymer compound (Chemical formula 1), wherein the material constituting the ion conductive polymer composition has a polyether skeleton as a basic skeleton and the polyether moiety is a random copolymer of oxyethylene and oxypropylene. When,
The method for joining a dielectric and an ion conductive polymer composition according to claim 1 or 2, which is mainly composed of polyalkylene glycol, polyalkylene glycol dimethyl ether and ammonium salt. [Chemical 1] 5. Acetone, methyl ethyl ketone, tetrahydrafuran, propylene carbonate, ethylene carbonate,
The method for joining a dielectric and an ion conductive polymer composition according to claim 4, wherein the method is at least one kind of organic solvent selected from polyalkylene glycol dimethyl ether.