JP2001338848A - Electric double layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a sheetlike thin electric double layer capacitor whose capacitance is large. SOLUTION: The electric double layer capacitor is constituted in such a way that a beltlike separator 19 is sandwiched between beltlike aluminum foils 11, 12 in which polarizing electrode layers 15, 16 are formed respectively on faces on one side, that they are formed up in a folding screen shape, and that the separator 19 is impregnated with an electrolytic solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric double layer capacitor, and more particularly to a thin and small electric double layer capacitor.

[0002]

2. Description of the Related Art Conventional electric double-layer capacitors include, in addition to a wound type such as an electrolytic capacitor, a band-shaped separator 61 which is folded into a folding screen as shown in FIG. Polarizable electrode layers 62, 62 and 6
A collecting electrode 64 made of a metal plate provided with 3, 63;
64 and 65 and 65,.
Gaps 66, 66,... And 6 generated by folding
7, 67... And the separator 61 is impregnated with an electrolytic solution.

[0003]

The above-mentioned wound type is essentially unsuitable for applications requiring a thin and high capacity. Further, the structure shown in FIG. 6 requires a metal plate as a collecting electrode, so that the thickness of the metal plate restricts the reduction in thickness of the product. In addition, the structure shown in FIG. It was troublesome and could not be produced efficiently. Therefore, the present invention aims to realize an ultra-thin, high-capacity capacitor having a thickness of, for example, 1 mm or less.

[0004]

According to the present invention, a required number of collector electrodes provided with a polarizable electrode layer on the surface of a band-shaped metal foil and a required number of band-shaped separators are alternately stacked, and this is folded into a folding screen. By folding and impregnating the separator with an electrolytic solution, an electric double layer capacitor element is formed and sealed in a suitable bag. Lead tabs made of a thin metal plate are mechanically and electrically connected to each collector electrode, and these lead tabs are led to the outside through a sealing opening of the bag. It is desirable that the capacitor element be housed in the above-described bag by being sandwiched between thin plates of a highly rigid metal or hard synthetic resin.

[0005]

As described above, in the present invention, since a collector electrode provided with a polarizable electrode layer on a strip-shaped metal foil is used, a collector electrode provided with a polarizable electrode layer on a metal plate is used. Compared with the capacitor element shown in FIG. 6, the thickness required for obtaining the required capacity can be greatly reduced, and for example, a capacitor having a thickness of several hundred μm or less can be manufactured. In addition, the capacitor element shown in FIG. 6 has to be inserted into the gap between the separators one by one for each folding while folding the separator into a folding screen, which is extremely inefficient. In the present invention, since the separator and the collecting electrode are stacked and folded into a folding screen, the production is much more efficient.

Further, the thinner the capacitor element formed by folding as described above, the lower the rigidity is, and when an external force is applied, the capacitor element may be deformed and the polarizable electrode layer may be separated from the collector electrode. However, when the capacitor element is housed in an exterior bag, the resistance to external force can be increased by attaching a reinforcing plate made of metal or a hard synthetic resin to both sides of the element.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In an electric double layer capacitor, a first and a second layer comprising a porous carbon layer are separated by an electrolytic solution.
It is necessary to make the polarizable electrode layers face each other. For this purpose, a combination of a collector electrode composed of a plurality of band-shaped metal foils having a polarizable electrode layer and one or more band-shaped separators is used. In the first combination, two collector electrodes each having a polarizable electrode layer on one surface and one separator are used, and the collector electrode and the separator are overlapped with the polarizable electrode layer facing each other with the separator interposed therebetween. Stack. In the second combination, two collectors having a polarizable electrode layer on one side, one or more collectors having a polarizable electrode layer on both sides, and a plurality of separators are used. Electrodes and separators are alternately stacked. In that case, collector electrodes having a polarizable electrode layer only on one side are placed on both outer sides.

[0008] The polarizer electrode layer may be provided on the collector electrode in a continuous state over the entire surface. However, the polarizer electrode layer peels off at a portion where it is folded when folded in a folding screen shape, and the peeled material is collected. It is desirable not to provide a polarizable electrode layer at a portion to be bent because there is a risk of short-circuiting between them. As a bag for the exterior, a laminated film in which a low-melting material such as polypropylene or polyethylene is laminated on a heat-resistant material such as polyester, nylon, metal foil, or paper is suitable.

[0009]

Embodiment 1 As shown in FIG. 1, lead tabs 13 and 14 made of aluminum thin plate are attached to one side of each of strip-shaped aluminum foils 11 and 12 by welding, and the other side is made of, for example, colloidal graphite. The polarizable electrode layers 15 and 16 made of carbon fine particles are respectively applied to obtain a pair of collector electrodes 17 and 18. With the polarizable electrode layers 15 and 16 facing each other, a separator 19 made of a fibrous material is stacked between the collecting electrodes 17 and 18 and the resultant is folded into a folding screen.

After the folded object 10 is impregnated with an electrolytic solution in a vacuum, as shown in FIG. 2, reinforcing plates 21 and 22 made of aluminum or stainless steel are superimposed on the folded object, and
3 and 14 are housed in a laminated resin bag 23 in a state of being outside, and the bag 23 is heat-sealed at the positions of the lead tabs 13 and 14. Reference numeral 24 denotes this heat sealing portion.

[0011]

Embodiment 2 As shown in FIG.
Lead tabs 13 and 14 made of a thin aluminum plate are attached to one side of each of 1 and 12 by welding. On the opposite surface, as shown in FIG. 4, sections 32, 32,... Where folds 31, 31,.
, And 33, 33,..., And polarizable electrode layers 34, 34,.
Is attached in an island shape to obtain a pair of collector electrodes 36 and 37. As in the first embodiment, the separator 19 is interposed between the collecting electrodes 36 and 37 and folded in a folding screen shape to obtain a folded product, which is impregnated with an electrolytic solution, as shown in FIG.
The bag 22 is housed in a bag 23 together with the bag 22, and the bag mouth is heat-sealed.

[0012]

Third Embodiment As shown in FIG. 5, in addition to the collector electrodes 36 and 37 of the second embodiment, the island-shaped aluminum foil 52 shown in FIG. -Like polarizable electrode layers 44, 44 ...
. And the same island-shaped polarizable electrode layers 53, 53,.
The collector electrode 55 having 4, 54,... Is manufactured, and the collector electrode 36-the separator 56-the collector electrode 55-the separator 57-
The collector electrodes 37 are superposed in this order. At this time, the collecting electrodes 36 and 37
Of the polarizable electrode layers 34 and 35 face the separators 56 and 57, respectively.

This stack is folded into a folding screen and impregnated with an electrolytic solution to form a bag 2 together with reinforcing plates 21 and 22 as shown in FIG.
3 and the bag mouth is sealed. Lead tabs 13 and 15
Are electrically connected to each other outside of the bag mouth, and a capacitance appears between this and the lead tab 51. In this embodiment, only one collector electrode 55 having polarizable electrode layers 52 and 53 on both surfaces is interposed between the collector electrodes 36 and 37, but a plurality of similar collector electrodes are interposed between the collector electrodes 36 and 37. It may be provided with a separator interposed.

[0014]

As is apparent from the above embodiments, the present invention is a stack of a band-shaped collector and a band-shaped separator and folded in a folding screen shape. Can be used, and not only can a thin plate-shaped large-capacity capacitor be obtained, but also the production thereof can be remarkably facilitated as compared with a conventional plate-shaped electric double layer capacitor.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an electrode structure according to a first embodiment of the present invention.

FIG. 2 shows a finished product of the above embodiment, wherein (a) is a plan view,
(B) is sectional drawing which follows the AA line in (a).

FIG. 3 is an explanatory diagram of an electrode structure according to a second embodiment of the present invention.

4 is a developed plan view of an electrode 46 in FIG.

FIG. 5 is an explanatory view of an electrode structure according to a third embodiment of the present invention.

FIG. 6 is an explanatory view of an electrode structure and a manufacturing method of a conventional flat electric double layer capacitor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 folding screen-like folded material 11, 12 strip-shaped aluminum foil 13, 14 lead tab 15, 16-polarity electrode layer 17, 18 collector electrode 19 separator 21, 22 reinforcing plate 23 laminate resin bag 24 heat sealing part 31 fold 32, 33 Resulting section 34, 35 Island-like polarizable electrode layer 36, 37 Collector electrode 51 Lead tab 52 Strip aluminum foil 53, 54 Island-like polarizable electrode 55 Collector electrode

Claims (8)

[Claims] 1. A pair of collector electrodes formed of a strip-shaped metal foil having a polarizable electrode layer formed on at least one surface thereof, and a separator is interposed therebetween, and the polarizable electrode layer faces the separator, and is stacked. An electric double-layer capacitor obtained by folding this stack into a folding screen and impregnating the separator with an electrolytic solution. 2. The electric double-layer capacitor according to claim 1, wherein each of the collector electrodes lacks the polarizable electrode layer in a section that is bent when the folding screen is folded. 3. The electric device according to claim 1, wherein a polarizable electrode layer is formed on one surface of each of the collecting electrodes, and a triple product of these and the separator is folded in a folding screen shape. Double layer capacitor. 4. A collector comprising a strip-shaped metal foil having a polarizable electrode layer on one side is provided on both sides of a collector comprising a strip-shaped metal foil having a polarizable electrode layer on both sides with a separator interposed therebetween. 2. The electric double layer capacitor according to claim 1, wherein a polar electrode layer is stacked facing the separators. 5. A plurality of collector electrodes made of a strip-shaped metal having polarizable electrode layers on both surfaces thereof, stacked with a separator interposed therebetween, and further comprising a collector electrode having polarizable electrode layers on one surface on both sides thereof. 2. The electric double-layer capacitor according to claim 1, wherein said electric double-layer capacitor is piled up with said polarizer electrode layer on one side facing said separator. 6. Each of the above-mentioned collector electrodes has a lead tab made of a thin metal plate extending laterally, and the folding screen-like folded object is accommodated in an airtight bag with the lead tab coming out of the bag mouth. 2. The electric double layer capacitor according to claim 1, wherein the bag mouth is sealed with the lead tab interposed therebetween. 7. The electric double layer capacitor according to claim 6, wherein the bag is a laminated film in which a low melting point resin film is laminated on a heat resistant film. 8. The electric double-layer capacitor according to claim 6, wherein the folding screen-like folded product is housed in the bag with both sides sandwiched between rigid reinforcing plates.