JP2007019211A - Electric double layer capacitor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric double layer capacitor whose manufacture cost can be reduced and to provide a manufacturing method of the capacitor. <P>SOLUTION: A housing object 10 of a packaging case is provided with one current collection board 1 which is formed of aluminum foil and is connected to a cathode-side, one current collection board 2 which is formed of aluminum foil and is connected to an anode-side, and three current collection boards 3 formed of long aluminum sheets. The current collection boards 1 and 2 are respectively bent in U shapes at two places in cross section view shapes. The current collection board 3 is bent in S shapes at four places. Polarized electrodes 4 consisting of carbon are arranged on surfaces and rear faces of the current collection boards 1 to 3. Two polarized electrodes 4 among 24 polarized electrodes 4 confront each other through a long separator 5 and function as polarized electrodes 4a and 4b. Thus, twelve single cells 7 are constituted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric double layer capacitor and a method for manufacturing the same, and more particularly to a technique for reducing the manufacturing cost.

  As disclosed in Patent Document 1 below, an electric double layer capacitor is provided with polarizable electrodes (positive electrode and negative electrode) facing each other across a separator, and is formed on the surface of the polarizable electrode in an electrolyte solution. It utilizes the double layer capacitance. Electric double layer capacitors are characterized by extremely large capacitance compared to ordinary capacitors such as aluminum capacitors. They are used for backup of electronic devices, power storage for home appliances and copiers, and for automobiles. A wide range of uses has begun, including power supplies for starting during idle stops, power supplies for hybrid vehicles, and power storage for peak shaving and leveling of wind power and solar power generation. This is a key to save energy and reduce carbon dioxide. Expected as a device.

  The electric double layer capacitor has different shapes such as a button type, a laminated type, and a wound type, but in each case, a positive electrode and a negative electrode composed of polarizable electrodes mainly composed of carbon particles such as activated carbon, and these Separators that separate the two electrodes are alternately stacked in an outer case provided with a release valve, and impregnated with an electrolytic solution (such as an electrolyte dissolved in a solution or an ionic liquid).

  Since the electric double layer capacitor does not involve a chemical reaction during charging and discharging, there is an advantage that a large current can be charged and discharged instantaneously and charging and discharging efficiency is good. In addition, it has the advantages that it can be charged and discharged more than 100,000 times, has a lifetime of 10 years or more, and is highly reliable. On the other hand, compared with a lithium ion battery etc., there exists a fault that a charging voltage is low and an energy density is low.

Therefore, as disclosed in Patent Document 1 below, a multilayer electric double layer capacitor in which a plurality of cell portions are electrically connected in series is used. In multilayer electric double layer capacitors,
The charging voltage can be increased by the number of stacked cells.

  Patent Document 2 below discloses a multilayer electric double layer capacitor in which the same number of positive and negative electrode bodies are sandwiched one by one with a two-fold separator.

JP 2004-47522 A JP 2003-124080 A

  A conventional multilayer electric double layer capacitor is composed of a relatively large number of parts for liquid sealing of an electrolytic solution. Therefore, there has been a problem that the manufacturing cost becomes high.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an electric double layer capacitor and a method for manufacturing the same that can reduce the manufacturing cost.

  The electric double layer capacitor according to the present invention comprises a separator, two polarizable electrodes facing each other across the separator, and a plurality of single cells each comprising two collector electrodes sandwiching the two polarizable electrodes from both sides. An electric double layer capacitor configured by electrically connecting in parallel to form a cell group and electrically connecting a plurality of the cell groups in series, wherein the collector electrode is a single collector. Formed as an electric plate, a plurality of current collector plates are provided in common over a plurality of single cells except for two connected to the negative electrode terminal and the positive electrode terminal, and polarizable electrodes are arranged on the front and back surfaces, respectively. Is done.

  The electric double layer capacitor according to the present invention comprises a separator, two polarizable electrodes facing each other across the separator, and a plurality of single cells each comprising two collector electrodes sandwiching the two polarizable electrodes from both sides. An electric double layer capacitor configured by electrically connecting in parallel to form a cell group and electrically connecting a plurality of the cell groups in series, wherein the collector electrode is a single collector. Formed as an electric plate, a plurality of current collector plates are provided in common over a plurality of single cells except for two connected to the negative electrode terminal and the positive electrode terminal, and polarizable electrodes are arranged on the front and back surfaces, respectively. Is done. Therefore, the manufacturing cost can be reduced by reducing the number of parts.

<Embodiment 1>
1 to 3 are a developed schematic view, a cross-sectional view, and a top view showing the structure of the multilayer electric double layer capacitor 100 according to the first embodiment, respectively. That is, FIG. 1 shows the electric double layer capacitor 100 shown in FIGS. 2 to 3 in which the stored item 10 stored in the outer case 20 is taken out and developed.

  As shown in FIG. 1, the package 10 of the outer case 20 includes one current collector plate 1 made of aluminum foil and connected to the negative electrode side, and one current collector plate 2 made of aluminum foil and connected to the positive electrode side. One and three current collecting plates 3 made of a long aluminum foil sheet are provided. The current collector plates 1 and 2 are each bent in a U shape at two locations in the cross-sectional view, and the current collector plate 3 is bent into an S shape at four locations. Each of the current collecting plates 1 and 2 folded into a U shape at two locations has one region inside the recess, and the current collecting plates 3 bent into an S shape at four locations are arranged in the recess. Although it has two areas on the inner side, these areas are further divided into two parts by combining the current collector plates 1 to 3 adjacent to each other. That is, each of the current collector plates 1 and 2 has two single cell regions inside the recess, and the current collector 3 has four single cell regions inside the recess. It becomes.

  Polarizable electrodes 4 made of carbon are arranged on the front and back surfaces of current collector plates 1 to 3 corresponding to these single cell regions. In the present specification, of the polarizable electrodes 4, those that are negatively polarized are also called polarizable electrodes 4a, and those that are positively polarized are also called polarizable electrodes 4b.

  Three polarizable electrodes 4 a are arranged on the current collector 1, three polarizable electrodes 4 b are arranged on the current collector 2, and three polarizable electrodes 4 a and 3 are arranged on the current collector 3. The polarizable electrode 4b is disposed. That is, the electric double layer capacitor 100 has 3 + 3 + 3 × 2 × 3 = 24 polarizable electrodes 4. Each of the 24 polarizable electrodes 4 is opposed to each other via a long separator 5 and functions as polarizable electrodes 4a and 4b, thereby constituting 12 single cells 7. That is, each of the current collecting plates 1 and 2 is a set of three collecting electrodes, and the current collecting plate 3 is a set of six collecting electrodes.

  The separator 5 has flexibility and is bent into an S shape. Since one separator 5 extends over three single cells 7, four separators 5 are arranged in the electric double layer capacitor 100 having 12 single cells 7.

  Three single cells 7 corresponding to one separator 5 are electrically connected in parallel to form one cell group 6. Four cell groups 6 are electrically connected in series to form one electric double layer capacitor 100.

  FIG. 4 is a developed schematic view showing the configuration of the long current collecting plate 3 shown in FIG. On the surface side of the current collecting plate 3, a liquid seal portion 8 a for performing liquid sealing of the electrolytic solution, one polarizable electrode 4 a, and two polarizable electrodes 4 b are formed. Further, on the back side of the current collector plate 3, a liquid seal portion 8 b for performing liquid sealing of the electrolytic solution, two polarizable electrodes 4 a, and one polarizable electrode 4 b are formed. As the material of the liquid seal portion 8, thermoplastic resins such as polyethylene and polypropylene, silicone rubber, fluorine rubber, butadiene rubber, and the like are used.

  As the polarizable electrode 4, a layer having a thickness of several tens to several hundreds μm is used in which activated carbon having a diameter of about several μm is bound with a fluorine resin such as PTFE (polytetrafluoroethylene) as a binder. It is done.

  Next, the structure of the electric double layer capacitor 100 will be described with reference to FIGS.

  The current collector 1 is connected to the negative terminal 30, and the current collector 2 is connected to the positive terminal 40. The negative electrode terminal 30 and the positive electrode terminal 40 are drawn out of the exterior case 20 in an electrically insulated and sealed state, respectively.

  The exterior case 20 that stores the storage 10 including the four cell groups 6 is composed of a laminate film in which a resin such as polyethylene is bonded to the surface of an aluminum foil. In addition, the outer case 20 is provided with a discharge valve 50. The discharge valve 50 is provided with a small through hole, and this through hole is normally closed by the valve, but when the internal pressure of the exterior case 20 increases, the valve opens and the through hole opens. Thus, the gas in the outer case 20 is released to the outside.

  Each cell group 6 is liquid-sealed by a packing material 60 and electrically insulated. As the packing material 60, thermoplastic resins such as polyethylene and polypropylene, silicone rubber, fluorine rubber, butadiene rubber, and the like are used.

  In FIG. 2, the separator 5 is in contact with an electrolyte reservoir 70 for storing the electrolyte solution vertically below (near the bottom of the outer case 20). Further, in the vertically upward direction (near the release valve 50 of the outer case 20), the separator 5 penetrates the packing material 60 and protrudes above the current collecting plates 1 to 3 to form the separator protrusion 80.

  Examples of the separator 5 include celluloses such as natural pulp, natural cellulose, solvent-spun cellulose, and bacterial cellulose, and non-woven fabric containing glass fiber and non-fibrillated organic fiber, as well as nylon 66, aromatic polyamide, wholly aromatic polyamide, Aromatic polyester, wholly aromatic polyester, wholly aromatic polyester amide, wholly aromatic polyether, wholly aromatic polyazo compound, polyphenylene sulfide (PPS), poly-p-phenylenebenzobisthiazole (PBZT), poly-p-phenylene Philylated forms such as benzobisoxazole (PBO), polybenzimidazole (PBI), polyetheretherketone (PEEK), polyamideimide (PAI), polyimide, polytetrafluoroethylene (PTFE), and many Quality film is used.

  It is preferable to use the same material as the separator 5 as the electrolyte reservoir 70. Further, by making the average pore diameter of the electrolyte reservoir 70 larger than that of the separator 5, when the electrolyte in the separator 5 in contact with the electrolyte reservoir 70 is insufficient, the electrolyte reservoir 70 is separated from the electrolyte reservoir 70 due to a difference in pore (pore) suction force. Since the electrolytic solution moves to the separator 5, it is possible to prevent shortage of the electrolytic solution at the positive electrode and the negative electrode. When activated carbon is used, the volume change of the electrolytic solution increases because the electrolyte intercalates. In particular, when nano-gate carbon is used, the electrolyte expands greatly during charging and contracts greatly during discharging, so that the electrolyte is insufficient during charging and overflows during discharging. In order to compensate for the excess or deficiency, the electrolyte reservoir 70 absorbs the electrolyte in a large pore when the electrolyte overflows. Further, the overflowing electrolyte solution is discharged to the separator protrusion 80.

  The separator protrusion 80 also functions as a part for releasing the gas generated in the single cell part 7. When the overvoltage of the polarizable electrode 4 made of carbon increases, the electrolytic solution, the carbon adsorbing group, and the carbon itself are decomposed to generate gases such as carbon dioxide, hydrogen, and carbon monoxide. In the conventional multilayer electric double layer capacitor, a mechanism for releasing the generated gas is insufficient for liquid sealing. In the electric double layer capacitor 100 according to the present embodiment, the gas generated from the separator protrusion 80 is released, thereby quickly increasing the gas pressure and releasing the gas from the release valve 50 to the outside. Destruction can be prevented. Therefore, after the gas is released, the electric double layer capacitor 100 can almost restore its original performance.

Further, in the present specification, the electrolytic solution refers to a liquid electrolytic solution containing the following electrolyte and solvent. That is, as the electrolyte, for example, a combination of a cation and an anion, the cation is quaternary ammonium, 1,3-dialkylimidazolium, or 1,2,3-trialkylimidazolium, and the anion is BF ₄ ⁻ , PF ₆ ^−. , ClO ₄ ⁻ , or CF ₃ SO ₃ ^— , AlCl ₄ ⁻ or BF ₄ ^{− of} 1-ethyl-3-methylimidazolium (EMI) or 1,2-dimethyl-3-propylimidazolium (DMPI). Salts such as are used. Examples of the solvent include propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, dimethoxymethane, diethoxyethane, γ-butyllactone, acetonitrile, and a mixed solvent of two or more of these selected from propionitrile. It is used. Further, a gel electrolyte may be used as the electrolyte solution, that is, the electrolyte solution. As the gel electrolyte, boron tetrafluoride-based gel electrolyte, polymer solid electrolyte, electrolyte containing a polyester compound, imidazolium-based ionicity, etc. A liquid or the like can be used.

  FIG. 5 is a developed schematic view showing a detailed configuration of the stored item 10 of the outer case 20 shown in FIG. The polarizable electrode 4 shown in FIG. 5 can be applied and formed on each of the current collector plates 1 to 3 using an existing method such as screen printing, barcode coating, or gravure printing. Similarly, a liquid seal portion 8 is formed around the polarizable electrode 4 using an existing method such as screen printing, barcode coating, or gravure printing.

  In the storage case 10 of the outer case 20, the plurality of current collecting plates 3 and the separators 5 except for the current collecting plates 1 and 2 of both electrodes have the same structure, and thus are suitable for mass production.

  As a manufacturing method, first, a plurality of current collector plates 3 made of a long aluminum foil sheet in which a total of six polarizable electrodes 4 are applied on the front surface and the back surface are manufactured. Next, the produced current collecting plates 3 are shifted from each other by a length corresponding to the two polarizable electrodes 4, and a separator 5 is sandwiched between the bellows using a paper folding machine or the like. Bend to stack. Thereby, the assembly to a structure as shown in FIG. 1 can be performed easily.

  Next, after the assembled current collecting plates 1 to 3 and the separator 5 are accommodated in the outer case 20, an electrolytic solution is injected through the separator protrusion 80. Thereby, the separator 5 and the electrolyte reservoir 70 can be impregnated with the electrolyte.

  As described above, in the electric double layer capacitor 100 according to the present embodiment, the current collecting plate 3 is provided in common over a plurality of single cells 6 by making it long, and the polarizable electrodes 4 are formed on both surfaces thereof. is doing. Therefore, the manufacturing cost can be reduced by reducing the number of parts.

  In addition, since the plurality of current collector plates 3 and the separators 5 have the same shape, the manufacturing cost can be further reduced by using these as repeat parts and reducing the number of component types.

  In the above description, the case where four cell groups 6 are configured using one current collector plate 1, 2 and three current collector plates 3 has been described. However, the number of current collector plates 3 can be changed. Thus, it is possible to configure an arbitrary number of cell groups 6 of two or more.

  In the above description, the case where all of the current collector plates 1 to 3 are made of aluminum foil has been described. However, when lithium ions are contained in the electrolyte, aluminum may be eluted from the current collector plate 1 on the negative electrode side. Therefore, in order to prevent this, a copper foil may be used as the material of the current collector plate 1.

<Embodiment 2>
In the first embodiment, as shown in FIG. 1, the case where the current collector plate 3 bent into an S shape at four locations is used has been described. However, the current collector plate 3 may be a combination of two current collector plates bent in a U shape at two locations.

  FIG. 6 is a developed schematic view showing the structure of the multilayer electric double layer capacitor according to the second embodiment. FIG. 6 shows a configuration in which the current collector plate 3 in FIG. 1 is combined with current collector plates 3a and 3b that are bent in a U shape at two locations. The current collecting plate 3a arranged on the negative electrode side is made of a copper foil sheet, and the current collecting plate 3b arranged on the positive electrode side is made of an aluminum foil sheet.

  Such a configuration is effective when lithium ions are contained in the electrolytic solution. That is, lithium ions can stabilize the potential at a low potential in the negative electrode, but have the property of eluting aluminum as described above. Therefore, aluminum from the current collector plate 3a is obtained by using an aluminum foil for the current collector plate 3b disposed on the positive electrode side and a metal foil made of a metal other than aluminum for the current collector plate 3a disposed on the negative electrode side. Elution can be prevented.

  These current collector plates 3 a and 3 b are manufactured separately and then joined to one current collector plate 3. Therefore, since the polarizable electrode 4 is formed separately in the process before bonding, it is possible to cope with the case where the heat treatment temperature of the carbon used as the material of the polarizable electrode 4 differs between the current collector plates 3a and 3b. That is, by separately heat-treating carbon at different temperatures, the polarizable electrode 4 is formed on each of the current collecting plates 3a and 3b, and then the current collecting plates 3a and 3b are joined to form one current collecting plate 3. do it. In the process after joining, manufacture and assembly can be performed in the same procedure as in the first embodiment.

  Thus, in this embodiment, the current collector plate 3 is configured by partially overlapping the current collector plate 3a made of a copper foil sheet and the current collector plate 3b made of an aluminum foil sheet, and the current collector plate 3a Is disposed on the negative electrode side, and the current collector plate 3b is disposed on the positive electrode side. Therefore, in addition to the effect of the first embodiment, there is an effect that aluminum elution from the current collector plate 3a can be prevented.

<Embodiment 3>
In the first embodiment, as shown in FIG. 1, the case where one separator 5 is arranged in three single cells 7, that is, one cell group 6 has been described. However, two separators 5 may be arranged in an overlapping manner.

  FIG. 7 is a developed schematic view showing the structure of the multilayer electric double layer capacitor according to the third embodiment. FIG. 7 shows a configuration in which two separators 5 are overlapped as a whole in FIG.

  Thus, since the electric double layer capacitor according to the present embodiment uses the separator 5 in a double configuration, in addition to the effects of the first embodiment, the negative polarizable electrode 4a and the positive polarizable electrode There exists an effect that an electrical short circuit with 4b can be prevented more certainly.

<Embodiment 4>
In the third embodiment, as shown in FIG. 7, a case has been described in which a plurality of separators 5 bent in an S shape are arranged in a stacked manner. However, not only the separator 5 bent into the S-shape but also a plurality of separators including separators of other shapes may be arranged in an overlapping manner.

  FIG. 8 is a developed schematic view showing the structure of the multilayer electric double layer capacitor according to the fourth embodiment. FIG. 8 shows a configuration in which the separator 5 in FIG. 1 is composed of four separators 5a to 5d.

  In FIG. 8, the separators 5a to 5d are arranged in this order from the negative electrode side to the positive electrode side. The separators 5a and 5d are linear, and the separators 5b and 5c are bent into a U shape. In the three single cells 7 included in one cell group 6, in the left single cell 7, the entire separator 5a and one linear portion of the separator 5b are interposed between the polarizable electrodes 4a and 4b, In the single cell 7, the other linear portion of the separator 5b and one linear portion of the separator 5c are interposed between the polarizable electrodes 4a and 4b, and in the single cell 7 on the right side, the other linear portion of the separator 5c is interposed between the polarizable electrodes 4a and 4b. The straight portion and all of the separator 5d are interposed.

  By configuring the separator 5 from a plurality of separators 5a to 5d, it is possible to easily handle the separator 5 in the manufacturing process. Such a configuration is effective, for example, when the polarizable electrode 4 is not formed on the current collector plate 3 but formed on the separators 5a to 5d in the manufacturing process. That is, first, the separators 5 a to 5 d are impregnated with a gel electrolyte or an ionic liquid, and then the polarizable electrode 4 is formed on the separators 5 a to 5 d and then assembled with the current collector plate 3.

  Thus, in this Embodiment, since the separator 5 is comprised by overlapping several separators 5a-5d partially, in addition to the effect of Embodiment 3, handling of the separator 5 in a manufacturing process is carried out. There is an effect that can be easily performed.

<Embodiment 5>
In the first to fourth embodiments, as shown in FIGS. 1 and 6 to 8, a plurality of single cells 7 are formed by combining the U-shaped current collector plates 1 and 2 and the S-shaped current collector plate 3. Explained when to do. In the U-shaped current collecting plates 1 and 2 and the S-shaped current collecting plate 3, it is possible to increase the number of single cells 7 by providing a plate-like (linear in a cross-sectional view) metal member. .

  FIG. 9 is a developed schematic view showing the structure of the multilayer electric double layer capacitor according to the fifth embodiment. FIG. 9 is a plan view of FIG. 1. In FIG. 1, one member 91 made of a plate-like metal is provided inside the U-shaped current collector plates 1 and 2, and the plate is placed inside the S-shaped current collector plate 3. Two members 92 made of metal are provided. The members 91 and 92 are made of the same metal (aluminum foil or the like) as the current collector plates 1 and 2 and the current collector plate 3, respectively, and are electrically connected to the current collector plates 1 and 2 and the current collector plate 3. ing. In FIG. 9, for the convenience of illustration, the case where there is one current collecting plate 3 is shown.

  In FIG. 9, the number of single cells 7 included in one cell group 6 increases by two by providing one member 91 and one member 92. That is, the number of single cells 7 increases from three to five.

  As described above, the electric double layer capacitor according to the present embodiment is provided with the members 91 and 92 on the current collecting plates 1 and 2 and the current collecting plate 3, respectively. The number of cells 7 is increased. Therefore, in addition to the effect of the first embodiment, there is an effect that the thickness can be increased and the capacity can be increased without changing the shape and size.

  In the above description, the case where the number of current collector plates 3 is one has been described. However, the number of current collector plates 3 is not limited to one, and even when there are a plurality of current collector plates 3 as shown in FIGS. By providing the members 92 on each current collecting plate 3, it is possible to increase the number of single cells 7 included in one cell group 6 as in FIG.

<Embodiment 6>
In the fifth embodiment, as shown in FIG. 9, the number of single cells 7 included in one cell group 6 is increased by two by providing one member 91 and one member 92. Yes. However, the number of single cells 7 included in one cell group 6 may be further increased by providing more members 91 and 92.

  FIG. 10 is a developed schematic view showing the structure of the multilayer electric double layer capacitor according to the sixth embodiment. FIG. 10 is a diagram in which the number of members 91 and 92 provided for one cell group 6 in FIG. 9 is increased from one to three. As a result, the number of single cells 7 included in one cell group 6 is increased from four in FIG. 9 by four to nine.

  As described above, in the electric double layer capacitor according to the present embodiment, by providing an arbitrary number of members 91 and 92 for one cell group 6, the capacitance can be arbitrarily set without changing the shape and size. Can be increased. Therefore, in addition to the effects of the fifth embodiment, it is possible to respond to various uses and needs without changing the specifications, and it is possible to reduce the cost.

FIG. 3 is a developed schematic diagram showing the structure of the electric double layer capacitor according to the first embodiment. 1 is a cross-sectional view showing a structure of an electric double layer capacitor according to Embodiment 1. FIG. 1 is a top view showing a structure of an electric double layer capacitor according to a first embodiment. FIG. 3 is a developed schematic diagram illustrating a structure of a current collector plate according to Embodiment 1. FIG. 3 is a developed schematic diagram showing a detailed configuration of a stored item in an outer case of the electric double layer capacitor according to the first embodiment. FIG. 5 is a developed schematic diagram showing a structure of an electric double layer capacitor according to a second embodiment. FIG. 5 is a developed schematic diagram showing the structure of an electric double layer capacitor according to a third embodiment. FIG. 6 is a developed schematic diagram showing a structure of an electric double layer capacitor according to a fourth embodiment. FIG. 10 is a developed schematic diagram showing the structure of an electric double layer capacitor according to a fifth embodiment. FIG. 10 is a developed schematic diagram showing the structure of an electric double layer capacitor according to a sixth embodiment.

Explanation of symbols

1 to 3 Current collector plate, 4 polarized electrode, 5 separator, 6 cell group, 7 single cell, 8 liquid seal part, 10 container, 20 outer case, 30 negative terminal, 40 positive terminal, 50 discharge valve, 60 packing Material, 70 Electrolyte reservoir, 80 Separator protrusion, 91, 92 member, 100 Electric double layer capacitor.

Claims (9)

A cell group in which a plurality of single cells each composed of a separator and two polarizable electrodes opposed via the separator and two collector electrodes sandwiching the two polarizable electrodes from both sides are electrically connected in parallel. An electric double layer capacitor configured by electrically connecting a plurality of the cell groups in series,
The collector electrode is formed as a single current collector plate,
The plurality of current collector plates are provided in common over the plurality of single cells except for two connected to the negative electrode terminal and the positive electrode terminal, and the polarizable electrodes are arranged on the front and back surfaces, respectively. Double layer capacitor. The electric double layer capacitor according to claim 1,
The plurality of current collector plates provided in common over the plurality of single cells have the same shape as each other,
The separator is an electric double layer capacitor provided in common over a plurality of the single cells. The electric double layer capacitor according to claim 2,
The plurality of current collector plates provided in common over the plurality of single cells are bent so that the cross-sectional shape is S-shaped,
The two current collector plates connected to the negative electrode terminal and the positive electrode terminal are electric double layer capacitors that are bent so that the cross-sectional shape is U-shaped. The electric double layer capacitor according to claim 3,
The current collector plate bent in an S-shape and the current collector plate bent in a U-shape each have a plate-like member electrically connected to itself inside each recess. The electric double layer capacitor according to any one of claims 1 to 4,
The separator is an electric double layer capacitor in which a plurality of separators are provided partially or entirely overlapped. The electric double layer capacitor according to any one of claims 1 to 5,
An electric double layer capacitor in which two of the plurality of current collector plates provided in common over the plurality of single cells are partially overlapped. The electric double layer capacitor according to any one of claims 1 to 6,
An outer case for immersing and storing the plurality of cell groups in an electrolytic solution, and an electrolytic solution reservoir provided in the outer case for storing the electrolytic solution;
The separator is an electric double layer capacitor in contact with the electrolyte reservoir. The electric double layer capacitor according to claim 7,
A packing material provided in the outer case for storing the electrolytic solution;
The separator is an electric double layer capacitor that penetrates the packing material and protrudes above the current collecting plate. A method for manufacturing an electric double layer capacitor according to any one of claims 1 to 8,
A method of manufacturing an electric double layer capacitor comprising a step of bending a bellows with the separator interposed therebetween while shifting a plurality of the current collector plates.

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