JPH03283521A - Manufacture of electric double layer capacitor - Google Patents

Abstract

PURPOSE:To join a polarizable electrode firmly with a current collector without damaging the current collector by forming the current collector after rolling a conductive resin that is softened by heating and welding the polarizable electrode under pressure before the current collector becomes hard and further, burying its electrode up to a prescribed depth in the above collector. CONSTITUTION:Both openings of a frame consisting of an insulator that is formed into a cylindrical shape are closed by two sheets of current collectors 1 that are formed into each plate like shape by conductive rubber and the inside of the frame 2 is shut tight to the outside. As the polarizable electrode 4 is pressure-welded in a state that the current collector 1 is softened and its electrode is buried up to a depth of (t), a conductive resin that is excluded by burying the polarizable electrode 4 rises around its electrode 4 when thermocompression bonding is performed after the current collector 1 becomes hard and this eventually results in the development of wrinkles. However, the whole current collector 1 is so flexible that stress distribution inside the current collector 1 becomes uniform and then the development of wrinkles and the like is prevented. Further, changes in the side form of the electrode 4 renders bonding strength obtained between the electrode and the current collector 1 more powerful.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing an electric double layer capacitor using a porous sintered body composed of activated carbon fine particles as a polarizable electrode, and particularly relates to a method for manufacturing an electric double layer capacitor using a porous sintered body composed of activated carbon fine particles as a polarizable electrode. The present invention relates to a method of manufacturing an electric double layer capacitor, which is characterized by a method of coupling with.

(Prior Art) In recent years, capacitors using the electric double layer principle have been developed for use as backup power sources for memories in electronic devices, and have been widely used by being incorporated into microcomputers, IC memories, and the like.

For example, a polarizable electrode is a sintered body made of a mixed powder of carbon powder with a large specific surface area and a metal powder that is inert to the electrolytic solution, and the polarizable electrode is connected to at least two An electric double layer capacitor was proposed in which the electric double layer capacitors were arranged in a single layer and sealed in an outer can containing an electrolyte.
It is disclosed in Japanese Patent No. 24100.

Such an electric double layer capacitor is normally used by collecting the electric charge of the polarizable electrode to a current collector made of a conductive film connected to the polarizable electrode. If the current collector is simply brought into contact with the current collector, the contact resistance between the two becomes large, resulting in an increase in internal resistance and a problem in that the output characteristics deteriorate.

Therefore, there is a method to firmly connect the polarizable electrode and the current collector by thermocompression bonding to the current collector, which is a polarizable electrode, and allowing a part of the current collector to penetrate into the porous part of the surface of the polarizable electrode. Patent application Hei 1-2
No. 32243.

In addition, the surface of the current collector is once dissolved with a volatile solvent, and a part of the current collector is pressed into contact with the polarizable electrode to penetrate into the porous part of the surface of the polarizable electrode, and then the solvent is volatilized. Japanese Patent Application No. 2-39499 discloses a method of firmly connecting a polarizable electrode and a current collector by hardening the current collector again.

(Problems to be Solved by the Invention) Among the above methods, in which the polarizable electrode is thermocompression bonded to the current collector, the heating temperature of the polarizable electrode is not constant, and if the polarizable electrode is pressed against the current collector with the same pressure, In the case of high-temperature polarizable electrodes, there is a risk that the electrolyte may leak to the outside because it penetrates the current collector.

Furthermore, since the thermal energy transferred to the current collector differs depending on the location, wrinkles may occur in the current collector.

Therefore, the polarizable electrode must be thermocompression bonded at low temperature and low pressure, which reduces the bonding force between the polarizable electrode and the current collector.

Further, in the case of a method that once dissolves the surface of the current collector, the amount of dissolution is limited, so the bonding force between the polarizable electrode and the current collector is still not satisfactory.

Therefore, in both proposed electric double layer capacitors, there is a risk that the polarizable electrodes may peel off from the current collector due to vibration or expansion of the polarizable electrodes due to impregnation with an electrolytic solution, and the performance as a capacitor may deteriorate.

The present invention was made in view of such problems,
The purpose is to provide a method for manufacturing an electric double layer capacitor that has stable performance by firmly bonding a polarizable electrode and a current collector without damaging the current collector.

(Means for Solving the Problems) According to the present invention, in a method for manufacturing an electric double layer capacitor having a polarizable electrode made of a conductive porous sintered body connected to a current collector made of a conductive resin, a step of rolling the heated and softened conductive resin to create the current collector; a step of press-contacting the polarizable electrode to the current collector while the rolled current collector is in a softened state and embedding the polarizable electrode in a predetermined amount; It is possible to provide a method for manufacturing an electric double layer capacitor, which comprises a step of cooling and hardening a current collector in which a polarizable electrode is embedded.

(Function) In the present invention, a conductive resin is heated and softened and rolled to form a current collector, and before the current collector hardens, a polarizable electrode is pressed into contact with the conductive resin to a predetermined depth within the current collector. Since the polarizable electrode is buried vertically, wrinkles and the like do not occur on the current collector, and the polarizable electrode can be firmly bonded to the current collector.

(Example) Next, an example of the present invention will be described in detail using the drawings.

FIG. 1 is a sectional view showing the structure of an electric double layer capacitor manufactured according to the present invention.

1 is a current collector made of conductive rubber and formed into a plate shape.

The two current collectors 1 close both openings of a frame 2 made of a cylindrical insulator, thereby sealing the inside of the frame 2 from the outside.

The sealed interior of the frame 2 is divided by a separator 3 made of a porous membrane.

Incidentally, the separator 3 may be formed of an ion-permeable membrane.

A plurality of polarizable electrodes 4 are bonded to the inner surface of each of the current collectors 1, and the inside of the frame 2 is filled with an electrolytic solution 5.

Next, the manufacturing method according to the present invention will be explained using FIG. 2.

FIG. 2 is a partial cross-sectional view showing the state of connection between the polarizable electrode and the current collector.

As shown in this figure, since the polarizable electrode 4 is pressed into contact with the current collector 1 in a softened state and buried to a depth t, unlike the conventional example described above, the current collector 1 is hardened and then thermocompression bonded. If this is done, the conductive resin rejected by embedding the polarizable electrode 4 will bulge around the polarizable electrode 4, causing wrinkles.
According to the method of the present application, since the entire current collector 1 has flexibility, the stress distribution inside the current collector 1 becomes uniform, and wrinkles and the like do not occur.

Further, by changing the side shape of the polarizable electrode 4, the bonding force with the current collector 1 can be made stronger.

FIG. 3 is a diagram showing another example of holding polarizable electrodes.

This figure (a) shows an example in which a plurality of notches corresponding to the protrusions 11 are provided on the outer circumference of the polarizable electrode 4, (b) shows an example in which the side surface of the polarizable electrode 4 is tapered, and (c ) shows an example in which grooves are carved around the entire circumference of the polarizable electrode 4, and (d) shows an example in which steps are provided in the entire circumference of the polarizable electrode 4.

Incidentally, a plan view of the polarizable electrode 4 before being buried is shown above each of (a) to (d).

Although the embodiments of the present invention have been described in detail above, various modifications can be made within the scope of the gist of the present invention, and these modifications are not excluded from the scope of the present invention.

(Effects of the Invention) According to the present invention, a conductive resin is heated and softened and then rolled to form a current collector, and before the current collector hardens, a polarizable electrode is pressed into contact with the current collector. Because the polarizable electrode is buried to a predetermined depth within the body, wrinkles do not occur on the current collector, and the polarizable electrode is firmly bonded to the current collector. It is possible to provide a method for manufacturing an electric double layer capacitor with stable performance in which the electrode does not peel off from the current collector.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of an electric double layer capacitor manufactured according to the present invention, FIG. 2 is a partial cross-sectional view showing the bonding state of a polarizable electrode and a current collector, and FIG. FIG. 7 is a diagram showing another example of holding a polar electrode. 1... Current collector, 4... Polarizable electrode.

Claims (1)

[Claims] In a method for manufacturing an electric double layer capacitor having a polarizable electrode made of a conductive porous sintered body connected to a current collector made of a conductive resin, the heated and softened conductive resin is rolled to form the current collector. a step of press-contacting a polarizable electrode to the current collector while the rolled current collector is in a softened state and embedding the polarizable electrode in a predetermined amount; and cooling and hardening the polarizable electrode or the buried current collector. A method for manufacturing an electric double layer capacitor, comprising the steps of: