JP2002313679A - Electric double-layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric double-layer capacitor that can be configured thinly and at the same time can be miniaturized. SOLUTION: Power collection metals 20 where an activated carbon electrode 10 is bonded are allowed to oppose one another, and at the same time a separator 30 and electrolyte are interposed among them. Further, a thermal bonding section 40 such as denatured polypropylene or denatured polyethylene is bonded in advance to the outermost periphery section of the power collection metals 20, the thermal bonding section 40 is heated and the power collection metals 20 are bonded each other for sealing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an electric double layer capacitor. More specifically, the present invention relates to a packaging method for an electric double layer capacitor and a method for extracting a current collecting metal.

[0002]

2. Description of the Related Art Currently used computers include:
An electric double layer capacitor is used for backing up a memory. This electric double layer capacitor is Al
Compared to a capacitor having a dielectric between electrodes represented by an electrolytic capacitor, the capacity per volume is 300 to 1000
It is twice as high, small in size and large in capacity, and has a long cycle life. The electric double layer capacitor has a structure in which an electrolyte exists between the two electrodes.

That is, an electric double layer capacitor operates on the principle that anions and cations in an electrolyte are physically adsorbed on a polarizable electrode on the surfaces of a positive electrode and a negative electrode, respectively, and electricity is stored. Therefore, the surface area of the adsorbed electrode is large. Is required. Therefore, at present, the specific surface area is 1000-3
000 (m ² / g) activated carbon is used as an electrode of this electric double layer capacitor.

In recent years, this electric double layer capacitor has been widely used as a backup power supply for various devices. With an increase in capacity of an application object, an increase in capacity of an electric double layer capacitor used as a backup is also desired. At this time, in the electric double layer capacitor having a large capacity, it is desirable that the working voltage is high, the internal resistance is low, and a large current can flow.

FIG. 9 shows the structure of an electric double layer capacitor. As shown in FIG. 1, an activated carbon electrode 1 is attached to each of the facing collecting electrodes 4, and a separator 2 is inserted between the activated carbon electrodes 1 to prevent a short circuit between the two electrodes. The electrolyte 3 is filled. As shown in FIG. 7, electricity is taken out from the electric double layer capacitor directly from the back surface of each collector electrode 4 which is a bipolar electrode. In addition, there is also a configuration in which it is directly taken out from the side portion of the collector electrode 4. In addition, in order to prevent the electrolyte 3 from leaking,
A seal structure is provided.

[0006]

In recent years, this electric double layer capacitor has been widely used as a backup power supply for various devices. With an increase in capacity of an application object, an increase in capacity of an electric double layer capacitor used as a backup is also desired. At the same time, attempts have been made to increase the energy density per weight and the energy density per volume of the capacitor, and to reduce the size of the capacitor when mounting it on equipment.

For example, attempts have been made to increase the energy density by improving the material of the electrode, increasing the amount of adsorbed ions per unit volume, and increasing the capacitance of the capacitor itself. In addition, as the packaging form of the capacitor, the conventional method of inserting it into a metal can and taking out only the electric take-out terminal, and the packaging with aluminum laminated film, which is composed of aluminum foil and resin film found in lithium batteries, etc. Are also being considered. FIG. 10 schematically shows a multilayer capacitor in which a plurality of flat-plate capacitors / single cells are stacked.

In this multilayer capacitor, a capacitor body 5 is laminated and surrounded by a frame-like packing 7.
Furthermore, the structure is sandwiched between the holding plates 6 from both sides and fastened with the bolts 8 and the nuts 9, so that the withstand voltage of the capacitor unit can be increased in proportion to the number of layers. However, since the internal resistance of the unit increases in proportion, the internal resistance (between the polarizable electrode-collector electrode and the cell) is reduced.
In other words, in order to increase the area of the contact portion which causes internal resistance, a configuration is adopted in which both ends of the laminate are sandwiched by the thick pressing plate 6 and fastened by the bolts 8 and the nuts 9. Further, the exterior holding components other than the capacitor in the laminate are heavier than the capacitor cells, which hinders an increase in energy density. The same applies to the case where an aluminum laminate film is used in order to improve the sealing performance with the outside air.

[0009]

According to a first aspect of the present invention, there is provided an electric double layer capacitor in which a current collecting metal having an activated carbon electrode bonded thereto is opposed to a current collector, and a separator and an electrolyte are interposed therebetween. Further, a heat bonding part such as denatured polypropylene or denatured polyethylene is bonded in advance to the outermost peripheral portion of the current collecting metal, and the heat bonding part is heated to bond and seal the current collecting metals to each other. And The electric double layer capacitor according to claim 2 of the present invention that solves the above-mentioned problem is the electric double layer capacitor according to claim 1, wherein the back surfaces of the current collecting metals are brought into contact with each other to connect the electric double layer capacitors in series. It is characterized by increasing the voltage and increasing the capacity. An electric double layer capacitor according to a third aspect of the present invention that solves the above-mentioned problem is characterized in that, in the first aspect, the thermal bonding portion functions as an insulating material in the electric double layer capacitor.

[0010]

[Embodiment 1] FIG. 1 is a schematic view of a flat electric double layer capacitor according to a first embodiment of the present invention. This embodiment shows the most basic configuration among the embodiments of the present invention. That is, this flat-type electric double layer capacitor has a current collecting metal 20 to which the activated carbon electrode 10 is adhered.
And a separator 30 and an electrolytic solution are interposed therebetween, and a thermal bonding portion 40 such as a modified polypropylene or a modified polyethylene is bonded in advance to the outermost peripheral portion of the current collecting metal 20 to form the thermal bonding portion. Reference numeral 40 indicates that the current collecting metals 20 are thermally bonded to each other and sealed. Here, an aluminum foil is used as the current collecting metal 20, and the activated carbon electrode 10 is electrically connected.

As the connection method, there are various methods such as a method of welding and connecting with a conductive adhesive, a conductive paint, a conductive resin, a method of spraying aluminum on an electrode surface and contacting the aluminum foil, and a method of applying the electrode itself to the aluminum foil. The method is fine. Examples of the separator 30 include a nonwoven fabric using cellulose or a synthetic resin or a synthetic resin in which pores are physically and chemically provided. In the outermost peripheral portion of such an electric double layer capacitor, the current collecting metal 20 is thermally bonded via a thermal bonding portion 40. As the thermal bonding portion 40, polypropylene (modified polypropylene) or polyethylene (modified polyethylene) modified with an acid or the like is used so as to easily adhere to aluminum.

The outermost peripheral portion of the electric double layer capacitor refers to a region where the collector metals 20 face each other without the separator 30 or the electrolytic solution interposed therebetween. In the present embodiment having the above-described configuration, the heat-bonding portions 40 made of denatured polypropylene or polyethylene adhere the current-collecting metals 20 made of aluminum foil to each other and insulate the current-collecting metals 20 from each other. Sealed to prevent liquid leakage (seal)
Therefore, the electric double layer capacitor can be made extremely thin and downsized.

That is, since the activated carbon electrode 10, the current collecting metal 20, the separator 30, and the heat bonding portion 40 have a simple structure, the material of the cell such as an end plate (holding plate) which has been conventionally used is not required. Was completed. Therefore, the number of parts can be reduced, the cost can be reduced, and the defect occurrence rate is almost eliminated. Also, by simplifying the components of the electric double layer capacitor in this way,
Small and lightweight capacitors can now be constructed. In particular, since the aluminum foil as the current collecting metal 20 is also used as the exterior body, the energy density can be increased.

[Embodiment 2] FIG. 2 is a schematic view of a flat electric double layer capacitor according to a second embodiment of the present invention. Since the electric double layer capacitor has a lower internal resistance than a general battery, in this embodiment, electricity is basically taken out from the back so that a large current can be taken out.

That is, each of the current collecting metals 20 to which the activated carbon electrode 10 is adhered is provided with an electric extraction portion 50 on the back surface thereof. The other configuration is the same as that of the first embodiment shown in FIG. In the present embodiment, since the electric double layer capacitor is configured to be thin similarly to the above-described first embodiment, the same effect as that of the first embodiment can be obtained. In addition, by taking out electricity from the back surface, the resistance loss of the terminal portion can be suppressed. And improved the reliability.

Embodiment 3 A method of manufacturing a flat electric double layer capacitor according to a first embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. First, as shown in FIG.
The joined body of the current collecting metal 20 and the activated carbon electrode 10 faces each other such that the activated carbon electrode 10 faces each other, and the separator 30 is inserted therebetween. Next, as shown in FIG. 3 (b), an electrolytic solution is contained between the current collecting metal 20, the activated carbon electrode 10, and the separator 30, and further, a heat bonding portion 40 at the outermost peripheral portion is provided.
Is thermally bonded to complete the sealing configuration of the capacitor.

Here, as shown in FIG. 3A, it is desirable that the heat bonding portion 40 is bonded in advance to the outermost peripheral portion of the current collecting metal 20 as a heat bonding film 41. The heat bonding film 41 bonded to the outermost peripheral portion of the current collecting metal 20 is
By the heating by the heater 60, the current collecting metals 20 are bonded to each other as the heat bonding portion 40. In the present embodiment, similarly to the above-described first embodiment, the collector metals 20 made of aluminum foil are bonded to each other by the thermal bonding portion 40 made of denatured polypropylene or polyethylene, and
Insulation of 0, and furthermore, sealing (sealing) so that the electrolyte does not leak, the other cell constituting materials could be reduced, and the electric double layer capacitor could be made thinner and smaller.

Embodiment 4 FIG. 4 shows a flat electric double layer capacitor according to a fourth embodiment of the present invention. In the present embodiment, as compared with the third embodiment, the insulating configuration at the outermost peripheral portion of the electric double layer capacitor is further ensured.

That is, as shown in FIG. 4, not only is the thermally bonded polypropylene or polyethylene film 41 modified beforehand thermally bonded to the outermost peripheral portion inside the current collecting metal 20, but also the modified polypropylene or polyethylene The thermal bonding film 42 is also thermally bonded to the outermost outer peripheral portion. The other configuration is the same as that of the third embodiment shown in FIG. In the present embodiment, similarly to the above-described third embodiment, the heat bonding film 41 can not only bond the current collecting metal 20 to each other as the heat bonding portion 40 but also form the electric double layer capacitor by the heat bonding film 42. An effect that the insulation at the outermost periphery can be further ensured is also exerted.

Embodiment 5 FIG. 5 shows a flat electric double layer capacitor according to a fifth embodiment of the present invention. In this embodiment, it is not necessary to take out electricity from the back. That is, as shown in FIG. 5, insulation is formed by attaching a denatured polypropylene or polyethylene heat bonding film 43 over the entire back surface of the current collecting metal 20. The other configuration is the same as that of the third embodiment shown in FIG. In the present embodiment, in addition to the same effect as that of the third embodiment described above, the insulation of the outermost peripheral portion of the electric double layer capacitor can be further ensured by the thermal bonding film 43, and the insulation over the entire back surface of the current collecting metal 20 can be achieved. This also has the effect of ensuring reliability.

[Embodiment 6] FIG. 6 shows a schematic view of a flat-type electric double layer capacitor according to a sixth embodiment of the present invention. In the present embodiment, a higher voltage and a larger capacity are achieved by combining a plurality of the electric double layer capacitors according to the first embodiment.

That is, since the single electric double layer capacitor shown in the first embodiment can take out electricity from the back surface, in this embodiment, as shown in FIG. 6, the single electric double layer capacitor shown in the first embodiment A plurality of double-layer capacitors are stacked as a single-cell capacitor. Other configurations are the same as those of the first embodiment shown in FIG. In the present embodiment, since the electric double layer capacitor is configured to be thin similarly to the above-described first embodiment, the same effect as that of the first embodiment can be obtained. Voltage and large capacity were achieved.

[Embodiment 7] FIG. 7 shows a schematic view of a flat electric double layer capacitor according to a seventh embodiment of the present invention. This embodiment relates to an improvement of the sixth embodiment. Example 6
In this embodiment, the current collecting metal 20 which is an aluminum foil is required for each individual cell capacitor. In this embodiment, the current collecting metal 20 is shared between adjacent single cell capacitors.

That is, the activated carbon electrodes 10 are provided on both sides of the current collector metal 20 which is an aluminum foil, and the thermally bonded layer 40 made of denatured polypropylene or polyethylene is also provided to provide a small, high-voltage electric double layer capacitor. It was created. In the present embodiment, the electric double layer capacitor is configured to be thin similarly to the above-described first embodiment, so that the same effects as those of the first embodiment can be obtained. In addition, a plurality of single-cell capacitors are stacked, and the current collecting metal 20 is shared. As a result, a higher voltage and a larger capacity can be achieved while further preventing an increase in size as compared with the sixth embodiment.

[Embodiment 8] FIG. 8 is a schematic view of a flat-type electric double layer capacitor according to an eighth embodiment of the present invention. This embodiment is an embodiment of the parallel connection. That is, the electric double layer capacitor 60 according to the above-described embodiment is arranged in a plane, and the parallel connection foil 70 is brought into contact with both surfaces thereof.

As described above, in this embodiment, when a voltage is not required in an electronic device or the like, the electric double layer capacitor 60 is used.
Can be simply spread on a flat surface and collectively collect electricity from above and below via the parallel connection foil 70. In addition, when the area of the capacitor is increased, there is an advantage that the configuration can be completed by simply arranging thin capacitors.

[0027]

As described above, according to the present invention, according to the present invention, the collector metals are bonded to each other by the heat-bonded portion made of denatured polypropylene or polyethylene, and these collectors are collected. Insulate the metal, and
In order to seal the electrolyte so that the electrolyte does not leak, the electric double layer capacitor can be made extremely thin and downsized.

[Brief description of the drawings]

FIG. 1 is a schematic view of a flat electric double layer capacitor according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a flat electric double layer capacitor according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of a method of manufacturing a flat electric double layer capacitor according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a flat-type electric double layer capacitor according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a flat electric double layer capacitor according to a fifth embodiment of the present invention.

FIG. 6 is a schematic view of a flat electric double layer capacitor according to a sixth embodiment of the present invention.

FIG. 7 is a schematic view of a flat electric double layer capacitor according to a seventh embodiment of the present invention.

FIG. 8 is a schematic view of a flat electric double layer capacitor according to an eighth embodiment of the present invention.

FIG. 9 is an operation principle diagram of the electric double layer capacitor.

FIG. 10 is a cross-sectional view of a conventional electric double layer capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Activated carbon electrode 20 Current collecting metal 30 Separator 40 Thermal bonding part 41, 42, 43 Thermal bonding film 50 Electric extraction part 60 Heater 70 Parallel connection foil

Claims (3)

[Claims] 1. A collector metal having an activated carbon electrode bonded thereto is opposed to the collector metal, a separator and an electrolytic solution are interposed therebetween, and a heat-bonded portion such as denatured polypropylene or denatured polyethylene is provided on the outermost periphery of the metal collector. An electric double-layer capacitor, wherein the heat-bonded portion is heated and the current-collecting metals are adhered to each other and sealed. 2. The electric device according to claim 1, wherein the back surfaces of the current collecting metals are brought into contact with each other, and the electric double layer capacitors are connected in series to achieve higher voltage and higher capacity. Double layer capacitor. 3. The electric double layer capacitor according to claim 1, wherein the thermal bonding portion functions as an insulating material in the electric double layer capacitor.