JP4593379B2 - Electric double layer capacitor - Google Patents

Description

  The present invention relates to an electric double layer capacitor. More specifically, the present invention relates to an electric double layer capacitor in which a negative electrode and a positive electrode of an electric double layer capacitor having a reference electrode are kept at a base potential and a charging voltage is increased.

  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.

  Regarding electric double layer capacitors, there are differences in shapes such as button type, stacked type, and wound type, but in both cases, positive and negative electrodes composed of polarizable electrodes mainly composed of carbon particles such as activated carbon, and these The separators separating 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 an electric double layer capacitor does not involve a chemical reaction during charging and discharging, it has the advantage that it can charge and discharge a large current instantaneously and has good charging and discharging efficiency. In addition, it has the advantages that it can be charged / discharged 100,000 times or more, 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. For example, in the case of an organic electrolytic solution, the potential window of the electrolytic solution is close to 6V, but the charging voltage is as low as about 2.5V. This is because only the non-Faraday current flows without any chemical reaction, so the electrochemical potential of the positive electrode and the negative electrode is not fixed, and when the positive electrode shifts to a noble potential, the decomposition potential of the electrolytic solution is reached. This is because degradation occurs, such as oxidative decomposition of the carbon or oxidation of the carbon adsorbing group to cause gas generation. The higher the charging voltage, the higher the probability that a degradation reaction will occur when the positive electrode is shifted to a noble potential.

  Therefore, in order to investigate the electrochemical potential of the electric double layer capacitor, in Patent Document 2 below, the potential of the positive electrode and the negative electrode is examined by providing a reference electrode.

  In addition, in order to increase the charging voltage by fixing the electrochemical potential of the positive electrode and the negative electrode to a base potential, methods such as doping the negative electrode with lithium and contacting the positive electrode and the negative electrode with lithium metal have been attempted. Yes.

  For example, Patent Document 3 below shows an example in which the negative electrode is doped with lithium to improve the life performance and the charging voltage is increased to 3.3V. Further, Patent Document 4 below shows an example in which the positive electrode and the negative electrode are brought into contact with lithium metal, the electrochemical potential of the positive electrode and the negative electrode is shifted to a base potential, and the charging voltage is increased to 3.0V.

JP 2003-124080 A JP 2002-75801 A JP 2000-124081 A JP 2000-150319 A

  However, in the electric double layer capacitor with a reference electrode disclosed in Patent Document 2, since the reference electrode is placed on top of the positive electrode and the negative electrode, is an exterior case that is nearly twice as large as a normal exterior case used? The positive electrode and the negative electrode had to be half the normal size, and it was not possible to equip a normal electric double layer capacitor with the reference electrode.

  Further, the method of doping lithium into the negative electrode in Patent Document 3 has a problem that the internal density increases because lithium ions increase the electric resistance, and the energy density does not increase even if the charging voltage is increased. It was.

  Further, in the method in which metal lithium is brought into contact with the positive electrode and the negative electrode disclosed in Patent Document 4, contact with the metal lithium is required before the positive electrode and the negative electrode are sealed in the outer case, which is troublesome and costly. In addition, since lithium metal was handled, sufficient safety was required. In addition, although an example in which metallic lithium remains in the outer case is also described, the lithium ion gradually melts from the metallic lithium and enters the electrolytic solution to increase the electrical resistance of the electrolytic solution. There is a problem that the energy density does not increase even when the charging voltage is increased.

  The present invention has been made to solve the above-described problems, and an object thereof is to obtain an electric double layer capacitor having a reference electrode that can be easily attached to a conventional electric double layer capacitor. It is what. In addition, an object of the present invention is to obtain an electric double layer capacitor in which the electrochemical potential of the positive electrode and the negative electrode is shifted to a base potential to increase the charging voltage.

In the electric double layer capacitor according to the subject of the present invention, a negative electrode or positive electrode carbon electrode layer is provided outside the negative electrode or positive electrode current collector plate of the outermost layer of the cell portion, and the carbon electrode layer is interposed via an electrolyte reservoir. A reference electrode carbon electrode layer in close contact with the reference electrode current collector plate is opposed, and the lead wire of the reference electrode current collector plate is exposed to the outside of the outer case in which the cell portion is accommodated. In addition, a redox agent is added to the electrolyte reservoir or the reference electrode carbon electrode layer, or the reference electrode carbon electrode layer is doped with lithium, and the electrolyte reservoir is isolated from the electrolyte solution of the separator. .

  Hereinafter, various embodiments of the subject of the present invention will be described in detail along with the effects and advantages thereof with reference to the accompanying drawings.

According to the subject of the present invention, the reference electrode can be easily provided while maintaining the size of the conventional positive electrode, negative electrode, and outer case as they are. Moreover, by short-circuiting the reference electrode and the negative electrode or the positive electrode, the potential of the negative electrode and the positive electrode can be kept at a low potential, and the charging voltage can be increased. Furthermore, it is possible to prevent lithium ions or redox agents from diffusing into the positive electrode and the negative electrode.

  The feature of this embodiment is that an electric double layer capacitor with a reference electrode that can monitor the potential of the positive electrode and the negative electrode is configured by facing the reference electrode on the outer side of the negative electrode or the positive electrode of the outermost layer of the cell part. is there. Further, by short-circuiting the reference electrode and one of the negative electrode and the positive electrode, the potential of the negative electrode and the positive electrode is shifted to a base potential so that the charging voltage can be made higher than before.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each figure, the element which attached | subjected the same code | symbol shall show the same or equivalent element.

(Embodiment 1)
FIG. 1 is a developed schematic view showing the structure of the electric double layer capacitor according to the present embodiment. 2 and 3 are a longitudinal sectional view and a front view, respectively.

  Referring to FIG. 1, a positive electrode including positive electrode current collector plate 6 and positive electrode carbon electrode layer 4, and a negative electrode current collector plate 5 and negative electrode carbon electrode layer 3 that are opposed to each other with porous separator 8 interposed therebetween. The cell portion 15 is configured by stacking a plurality of sets of negative electrodes.

  As the positive electrode carbon electrode layer 4 and the negative electrode carbon electrode layer 3, activated carbon having a diameter of several μm is bound to a fluorine resin such as PTFE (polytetrafluoroethylene) as a binder, and the thickness is several tens μm. A layer of up to several hundred μm is used.

  Aluminum foil is used as the positive electrode current collector plate 6, and the positive electrode carbon electrode layer 4 is formed on one side or both sides of the positive electrode current collector plate 6. Similarly, aluminum foil is used as the negative electrode current collector plate 5, and the negative electrode carbon electrode layer 3 is formed on one side or both sides of the negative electrode current collector plate 5.

  2 and 3, the positive electrode current collector plate 6 is connected to the positive electrode terminal 11, and the positive electrode terminal 11 is drawn out of the outer case 12 while being electrically insulated and sealed by the seal portion. . Similarly, the negative electrode current collector plate 5 is connected to the negative electrode terminal 10, and the negative electrode terminal 10 is drawn out of the outer case 12 while being electrically insulated and sealed by the seal portion.

  The reference electrode carbon electrode layer 1 is formed on the reference electrode current collector plate 2 and is opposed to the outermost negative electrode carbon electrode layer 3 via the electrolyte reservoir 7. The outermost negative electrode carbon electrode layer 3, the reference electrode carbon electrode layer 1, the reference electrode current collector plate 2, and the electrolyte reservoir 7 constitute a reference electrode portion 14. A lead wire 9 is drawn out from the reference electrode current collector plate 2, and the lead wire 9 is drawn out of the outer case 12 while being electrically insulated and sealed by a seal portion.

  The cell portion 15 and the reference electrode portion 14 are accommodated in the outer case 12. As the exterior case 12, a laminate film in which a resin such as polyethylene is bonded to the surface of an aluminum foil is used. The exterior case 12 is provided with a discharge valve 13. The discharge valve 13 is provided with a small through hole, and this through hole is normally closed by a valve. However, when the internal pressure of the outer case 12 increases, the valve opens and the through hole is opened. The gas in the outer case 12 is released to the outside.

  Examples of the separator 8 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.

  For the electrolyte reservoir 7, the same material as that of the separator 8 can be used.

Examples of the electrolyte include a combination of a cation and an anion, and 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 ^- of or salts, 1-ethyl-3-methylimidazolium (EMI), 1,2-dimethyl-3 AlCl propyl imidazolium (DMPI) ₄ ^- or BF ₄ ^-, such as Salt or the like is used, and the solvent is propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, dimethoxymethane, diethoxyethane, γ-butyllactone, acetonitrile, propionitrile, or two or more of these A mixed solvent or the like is used. In the present invention, the “electrolytic solution” means a liquid electrolyte solution containing these.

  The reference electrode carbon electrode layer 1 may be the same as the negative electrode carbon electrode layer 3 or the positive electrode carbon electrode layer 4, and the electrolyte solution in the electrolyte solution reservoir 7 is the same as the electrolyte solution impregnated in the separator 8. May be used.

  When the current terminal (that is, the lead wire 9) of the reference electrode (the portion composed of the reference electrode carbon electrode layer 1 and the reference electrode current collector plate 2) is not in contact with either the positive electrode or the negative electrode, the electrochemical potential of the reference electrode is Although it is stable and the absolute electrochemical potential is not known, the ratio of the overvoltage applied to the positive electrode and the negative electrode can be grasped by measuring the potential of the positive electrode and the negative electrode on the basis of this. Even if the absolute potential is not known, if the ratio of the overvoltage between the positive electrode and the negative electrode is known, it can be estimated which pole is the cause of the deterioration. In Patent Document 2, the same negative electrode is used as a reference electrode.

  By contacting metallic lithium with the reference electrode (that is, the reference electrode carbon electrode layer 1) or doping lithium ions, the electrochemical potential is stabilized, and the potentials of the positive electrode and the negative electrode based on the electrochemical absolute potential. Can be measured. In Patent Document 4, the positive electrode and the negative electrode are shifted to a base potential by short-circuiting with metallic lithium. Further, in Patent Document 3, lithium ions are doped by charging lithium fluoroborate as an electrolyte, propylene carbonate as an electrolytic solution, and metallic lithium as a counter electrode.

  In addition, substances having a redox potential such as fine silver and silver chloride, iodine and potassium iodine, vanadium ions and dyes are added as “redox agents” to the electrolyte reservoir 7 or the reference electrode carbon electrode layer 1. As a result, the electrochemical absolute potential of the reference electrode can be stabilized, the electrochemical absolute potential of the positive electrode and the negative electrode can be grasped, and a more accurate diagnosis can be performed. If the charging voltage is restricted or the cause of deterioration is in the positive electrode or the negative electrode, it can be used as a guideline for improvement.

  When a redox agent is added to the reference electrode together with the electrolytic solution, if the electrolyte reservoir 7 and the separator 8 are connected by the electrolytic solution, the redox agent will eventually diffuse into the positive electrode and negative electrode of the cell portion 15 to increase the internal resistance. (If no redox agent is added, there is no problem even if both 7 and 8 are connected). However, in the case of lithium ions, the internal resistance does not increase by diffusing to the positive electrode and the negative electrode of the cell portion 15 unless the concentration is high.

  On the other hand, when the electrolytic solution reservoir 7 is isolated from the electrolytic solution of the separator 8, a redox agent added to the reference electrode unit 14 can be freely selected. At the time of isolation, the electrolyte reservoir 7 and the separator 8 may be connected using a salt bridge.

  In particular, when a gel electrolyte is used as the electrolyte of the electrolyte reservoir 7, since the electrolyte reservoir 7 is gelled, the redox agent does not diffuse into the cell portion 15 (separator 8), and the electrolyte reservoir 7 can be easily isolated from the electrolyte solution of the separator 8. Here, as the gel electrolyte, various materials such as boron tetrafluoride-based gel electrolyte, polymer solid electrolyte, electrolyte containing a polyester compound, ionic liquid such as imidazolium can be used.

  Since a large charge transfer does not occur in the reference electrode due to charge and discharge of the positive electrode and the negative electrode, the reference electrode can perform a function of measuring a potential even when the electric resistance of the electrolyte is high. Moreover, even if the same electrolyte solution is used by making the size of the reference electrode carbon electrode layer 1 smaller than that of the positive electrode or the negative electrode, or making the size of the electrolyte solution reservoir 7 smaller than that of the separator 8, the electrolyte solution It becomes possible to isolate the reservoir 7 from the electrolyte solution of the separator 8.

  As for the arrangement of the reference electrode, the inventors have tried several arrangements such as arranging on the positive electrode and the negative electrode in the same manner as in Patent Document 2, or arranging it near the center of the cell part 15 or on both sides. As long as the positive electrode or the negative electrode is confronted with a large area, the present invention has been found to be able to function correctly as a reference electrode regardless of the position of the positive electrode or the negative electrode. That is, as shown in FIG. 1, the reference electrode is disposed on the outermost side surface, so that the size of the positive electrode and the negative electrode is not changed, and the size of the outer case 12 is hardly changed. Can be provided in the electric double layer capacitor. This makes it possible to carry out charge / discharge characteristics and life characteristics with the same shape as a conventional electric double layer capacitor while measuring the potential of the positive and negative electrodes at the reference electrode, for R & D and quality control of electric double layer capacitors. Great convenience.

  Furthermore, the inventors have found that when the lead terminal (lead wire) 9 of the reference electrode and the current terminal (negative electrode terminal) 10 of the negative electrode are short-circuited, the negative electrode and the positive electrode can be shifted to a base potential, It has been found that when the reference electrode and the negative electrode are short-circuited, the charging voltage can be increased by 0.5 V to allow charging / discharging. During the short-circuit, charge transfer occurs between the reference electrode and the positive electrode, so the function as the reference electrode is lost, and the negative electrode and the reference electrode have the same voltage with respect to the positive electrode. The reference electrode is placed at a lower potential rather than the same potential. When a redox agent for stabilizing the potential is present at the reference electrode, the electrochemical potential does not change even if the charge is moved a little. On the other hand, the potentials of the negative electrode and the positive electrode are not stable because they do not contain a redox agent that determines the potential. When shifted, the oxidation potential increases at the positive electrode, causing oxidative decomposition of the carbon adsorbing groups and the carbon itself, generating gases such as carbon dioxide, carbon monoxide, hydrogen, and so on. It is blocked by gas and the electrolyte solution cannot approach, resulting in an irreversible decrease in electric capacity. On the other hand, when the lead terminal 9 of the reference electrode and the current terminal 10 of the negative electrode are short-circuited, the negative electrode and the positive electrode are pulled to the stable electrochemical potential of the reference electrode and shifted to a base potential. As a result of various tests using the reference electrode, the inventors have found that the potential of the negative electrode and the positive electrode can be shifted to a base potential even when the short-circuited electrode is either the negative electrode or the positive electrode. This is presumably because the negative electrode and the positive electrode face each other with a large surface area, and the electrochemical absolute potential is reflected in the other.

  The negative electrode and the positive electrode of the electric double layer capacitor have no electrochemical absolute potential, which is a situation that cannot be considered in a primary battery or a secondary battery. Degradation is incurred, and sometimes the reference electrode lead terminal 9 and the negative electrode current terminal 10 are short-circuited, so that the negative electrode and the positive electrode are maintained at a base potential and the charging voltage is kept higher than before. Is possible.

  However, short-circuiting the reference electrode and the positive electrode must be in a discharged state, and if both are short-circuited in a charged state, the difference in electrochemical absolute potential between the reference electrode and the positive electrode is too large. As a result, a large current flows. When the current flows, the redox agent contained in the reference electrode is oxidized, and eventually, a reversible redox potential cannot be maintained. Therefore, it is desirable that the reference electrode and the negative electrode are short-circuited.

  In a state where there is no short circuit, the potential of the negative electrode and the positive electrode can be grasped even during charging / discharging of the electric double layer capacitor by using the reference electrode. By detecting the shift to the potential and short-circuiting the lead terminal 9 of the reference electrode and the current terminal 10 of the negative electrode, the negative electrode and the positive electrode can be returned to the base potential. Instead, it can be carried out as necessary while detecting at the reference electrode.

  As described above, according to the electric double layer capacitor according to the present embodiment, the negative electrode carbon electrode layer 3 is provided on the outer surface of the negative electrode current collecting plate 5 which is the outermost layer of the cell portion 15, and is positioned on the outermost layer. The negative electrode carbon electrode layer 3 is opposed to the reference electrode carbon electrode layer 1 in close contact with the reference electrode current collector plate 2 via the electrolyte reservoir 7, and the lead wire 9 of the reference electrode current collector plate 2 is accommodated in the cell portion 15. Since the outer case 12 is provided outside, the size of the conventional positive electrode, negative electrode, and outer case can be maintained as they are, and the reference electrode can be easily provided. Further, by short-circuiting the reference electrode and one of the negative electrode and the positive electrode, the potential of the negative electrode and the positive electrode can be kept at a low potential, and the charging voltage can be increased.

(Embodiment 2)
FIG. 4 is a front view showing the structure of the electric double layer capacitor according to Embodiment 2 of the present invention, in which the lead wire of the reference electrode is electrically connected to the negative current collector plate via the connection portion 16 and is short-circuited. Has been.

  In the second embodiment, since the reference electrode is connected to the negative electrode in the exterior case 12 in advance, the function as the reference electrode, that is, the negative electrode potential cannot be grasped based on the reference electrode. However, since the negative electrode can always be fixed at a base potential, the trouble of short-circuiting the lead wire of the reference electrode and the current terminal of the negative electrode or the positive electrode sometimes by an external circuit as in the first embodiment can be saved. Moreover, since a structure for drawing the lead wire of the reference electrode from the outer case 12 is not required, the potentials of the negative electrode and the positive electrode can be kept at a low potential and the charging voltage can be increased at low cost.

(Appendix)
In the first embodiment, the reference electrode carbon is provided with a negative electrode carbon electrode layer on the outer side of the negative electrode current collector plate at the outermost layer of the cell portion, and is in close contact with the reference electrode current collector plate via an electrolyte reservoir. Although the case where the electrode layers are opposed to each other has been described, a positive electrode carbon electrode layer is provided outside the positive electrode current collector plate of the outermost layer of the cell portion, and this is in close contact with the reference electrode current collector plate via an electrolyte reservoir. The reference electrode carbon electrode layer may be opposed to obtain the same effect.

  In the first and second embodiments, the multilayer electric double layer capacitor has been described. However, the present invention can also be applied to a wound type, button type, or box type electric double layer capacitor. Similar effects can be obtained.

  In the first and second embodiments, the current collector plate is used to isolate the electrolyte reservoir and the separator. However, another conductive separator plate may be added for isolation. As the separator, in addition to aluminum, a thin film such as titanium or copper can be used.

  While the embodiments of the present invention have been disclosed and described in detail above, the above description exemplifies aspects to which the present invention can be applied, and the present invention is not limited thereto. In other words, various modifications and variations to the described aspects can be considered without departing from the scope of the present invention.

It is an expanded schematic diagram which shows the structure of the electric double layer capacitor which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the structure of the electric double layer capacitor which concerns on Embodiment 1 of this invention. It is a front view which shows the structure of the electric double layer capacitor which concerns on Embodiment 1 of this invention. It is a front view which shows the structure of the electric double layer capacitor which concerns on Embodiment 2 of this invention.

Explanation of symbols

1 reference electrode carbon electrode layer, 2 reference electrode current collector plate, 3 negative electrode carbon electrode layer, 4 positive electrode carbon electrode layer, 5 negative electrode current collector plate, 6 positive electrode current collector plate, 7 electrolyte reservoir, 8 separator, 9 reference electrode Lead wire, 10 negative terminal, 11 positive terminal, 12 outer case, 13 release valve, 14 reference electrode part, 15 cell part.

Claims (8)

A positive electrode made of a positive electrode current collector plate and a positive electrode carbon electrode layer, a negative electrode made of a negative electrode current collector plate and a negative electrode carbon electrode layer, and a separator are alternately stacked. Provide a carbon electrode layer of negative electrode or positive electrode on the outside of the electric plate,
The carbon electrode layer provided on the outside of the current collector plate is opposed to the reference electrode carbon electrode layer in close contact with the reference electrode current collector plate via the electrolyte reservoir,
The lead of the reference electrode current collector plate, put on the outside of the outer case the cell unit is housed,
The reference electrode carbon electrode layer is doped with lithium,
The electrolyte reservoir is isolated from the separator electrolyte ;
Electric double layer capacitor. A positive electrode made of a positive electrode current collector plate and a positive electrode carbon electrode layer, a negative electrode made of a negative electrode current collector plate and a negative electrode carbon electrode layer, and a separator are alternately stacked. Provide a carbon electrode layer of negative electrode or positive electrode on the outside of the electric plate,
The carbon electrode layer provided on the outside of the current collector plate is opposed to the reference electrode carbon electrode layer in close contact with the reference electrode current collector plate via the electrolyte reservoir,
Lead the lead wire of the reference electrode current collector plate to the outside of the outer case in which the cell portion is housed,
A redox agent is added to the electrolyte reservoir or the reference electrode carbon electrode layer,
The electrolyte reservoir is isolated from the separator electrolyte;
Electric double layer capacitor. The electric double layer capacitor according to claim 1 or 2,
The lead wire of the reference electrode current collector plate is short-circuited with the negative electrode or the positive electrode,
Electric double layer capacitor. A positive electrode current collector plate and a positive electrode carbon electrode layer, a negative electrode current collector plate and a negative electrode carbon electrode layer negative electrode, and a negative electrode current collector plate of the outermost layer of the cell portion is formed by alternately laminating separators On the outside, a negative electrode carbon electrode layer is provided,
The negative electrode carbon electrode layer of the outermost layer is opposed to the reference electrode carbon electrode layer in close contact with the reference electrode current collector plate via the electrolyte reservoir,
Short-circuiting the reference electrode current collector plate and the negative electrode current collector plate inside an outer case in which the cell portion is housed,
The reference electrode carbon electrode layer is doped with lithium,
The electrolyte reservoir is isolated from the separator electrolyte;
Electric double layer capacitor. A positive electrode current collector plate and a positive electrode carbon electrode layer, a negative electrode current collector plate and a negative electrode carbon electrode layer negative electrode, and a negative electrode current collector plate of the outermost layer of the cell portion is formed by alternately laminating separators On the outside, a negative electrode carbon electrode layer is provided,
The negative electrode carbon electrode layer of the outermost layer is opposed to the reference electrode carbon electrode layer in close contact with the reference electrode current collector plate via the electrolyte reservoir,
Short-circuiting the reference electrode current collector plate and the negative electrode current collector plate inside an outer case in which the cell portion is housed,
A redox agent is added to the electrolyte reservoir or the reference electrode carbon electrode layer,
The electrolyte reservoir is isolated from the separator electrolyte;
Electric double layer capacitor. The electric double layer capacitor according to any one of claims 1 to 5,
A gel electrolyte is used as the electrolyte of the electrolyte reservoir,
Electric double layer capacitor. The electric double layer capacitor according to any one of claims 1 to 5,
The size of the reference electrode carbon electrode layer and the electrolyte reservoir is smaller than that of the positive electrode or the negative electrode, and the electrolyte reservoir is isolated from the electrolyte solution of the separator,
Electric double layer capacitor. The electric double layer capacitor according to any one of claims 1 to 5,
The electrolyte reservoir and the separator are connected by a salt bridge,
Electric double layer capacitor.

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