JPH1050569A - Electrical double-layer capacitor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrical double-layer capacitor for power, provided with an explosion-proof valve which has high operational reliability and can be manufactured inexpensively with high productivity. SOLUTION: An explosion-proof valve 1 which is put in the trough-hole 2a of a top lid 2 which seals an electrical double layer capacitor for power is provided with a columnar section 11 which is passed through the hole 2 and has an outside diameter F, corresponding to 90-120% of the inside diameter of the hole 2a, a first flange section 12 which has an outside diameter F, corresponding to 120-400% of the inside diameter of the hole 2a and is formed on one end side of the columnar section 11, so that the section 12 can be arranged on the external side face of the lid 2 on the outside of the case of the capacitor. A second flange section 13 which has an outside diameter G, corresponding to 110-140% of the inside diameter of the hole 2a and is formed on the other end side of the section 11, so that the section 13 can be arranged on the side face of the lid 2 on the inside of the case. A hole 14 which extends toward the section 12 side from the section 13 side and has a closed end in the section 12 is coaxially provided in the section 11 and, because of the hole 14, a valve section 15 is formed at the central part of the section 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-resistance large-capacity electric double-layer capacitor for power use having a capacitance of 50 F or more, and more particularly to an explosion-proof valve.

[0002]

2. Description of the Related Art A low-resistance large-capacity electric double-layer capacitor for power using an organic electrolytic solution has a feature that the energy density can be higher than that of an electric double-layer capacitor using an aqueous electrolytic solution because the withstand voltage can be increased.

In an electric double layer capacitor using an organic electrolyte, a separator is arranged between a pair of opposed electrodes each having a thin film-shaped polarizable electrode mainly composed of activated carbon powder supported on a metal current collector foil. The capacitor element is wound, and the element is impregnated with an electrolytic solution and stored in a metal case. The opening of the case is sealed with a rubber, a rubber-coated bakelite plate, or a phenol resin plate so that the electrolytic solution does not evaporate. And a rubber sealing member.

Japanese Patent Application Laid-Open No. 4-154106 proposes an electric double layer capacitor in which a capacitor element formed by laminating a large number of electrodes and separators is incorporated for the purpose of increasing the current and the capacity. For example, a capacitor element in which a large number of alternately stacked capacitor elements are alternately stacked with polarizer electrodes formed in a rectangular shape, and a positive electrode lead member and a negative electrode lead member connected to each end of the positive and negative electrodes by caulking or the like. It is housed in a case, impregnated with an electrolytic solution, and its opening is sealed with an aluminum upper lid.

Conventionally, electrodes constituting these electric double layer capacitors are mainly composed of activated carbon in which both the positive electrode and the negative electrode have a large specific surface area. These electric double layer capacitors for power are being developed as single cells having a capacitance of 10 to 10000 F and a rated voltage of 2.3 to 3 V.

[0006]

Since the energy stored in a large-capacity and high-voltage electric double layer capacitor is high, the internal resistance increases due to an external short circuit, reverse voltage application, overvoltage application and long-term use. Assuming such a case, a demand for a capacitor with high productivity while ensuring safety is increasing.

An electric double layer capacitor capable of charging and discharging with a large current of 10 A or more is promising for applications such as electric vehicles and regenerative braking energy storage. For practical use, the energy density is sufficiently high and rapid charging is required. It is desired to realize a low-cost electric double-layer capacitor capable of discharging, having a high withstand voltage, a long life and a high safety. Various safety valves have been considered for electric double layer capacitors so far, but the prevention of moisture intrusion from outside, which causes the withstand voltage of the capacitor to decrease,
No one satisfies both operating reliability and productivity, that is, manufacturing cost.

[0008]

Means for Solving the Problems The present invention has been made to achieve the above object, and the present invention provides a polarizer electrode layer comprising a carbon material, a conductive material and a binder on a metal current collector plate. The capacitor element impregnated with the organic electrolyte by winding or laminating the positive electrode and the negative electrode through a separator is housed in a bottomed cylindrical metal case, and the opening is sealed with an upper lid, and the same as above. In an electric double layer capacitor in which an explosion-proof valve is fitted into a through-hole formed in a lid, the explosion-proof valve is inserted into the through-hole and has an outer diameter of 90 to 120% of the inner diameter. A first flange portion having an outer diameter of 120 to 400% with respect to the inner diameter of the through hole, and formed at one end side of the column portion on the outer surface of the case of the upper lid; , With respect to the inner diameter of the through hole A second flange portion having an outer diameter of 10 to 140% and formed at the other end side of the columnar portion so as to be disposed on the inner side surface of the case of the upper lid; A hole whose end extending from the flange portion side toward the first flange portion is closed is provided coaxially, and a valve portion is formed substantially at the center of the first flange portion by the hole. It is characterized by.

The outer diameter of the first flange is 12 times the inner diameter of the through hole.
If it is less than 0%, when fitting the explosion-proof valve into the through-hole, there is a possibility that the whole is erroneously pushed into the inside of the capacitor by mistake. On the other hand, if it exceeds 400%, the area of the explosion-proof valve becomes unnecessarily large, which is not preferable.

The outer diameter of the columnar portion is 90% of the inner diameter of the through hole.
If it is less than 1, airtightness is insufficient, which is not preferable. 1
If it exceeds 20%, the surface of the explosion-proof valve is easily damaged when the explosion-proof valve is inserted, and the airtightness is undesirably reduced.

If the outer diameter of the second flange portion is less than 110% of the inner diameter of the through hole, when the internal pressure increases,
It is not preferable because the explosion-proof valve may be pushed out from the upper cover or the explosion-proof valve may be artificially pulled out from the outside before the original valve operates. On the other hand, if it exceeds 140%, it becomes difficult to insert the explosion-proof valve from the outside of the case into the through hole of the upper lid, or the pressure when removing the explosion-proof valve by applying air pressure after it is molded in a mold. Since the pressure is higher, the air pressure may cause the explosion-proof valve to operate (expand and burst), which is not preferable.

In the present invention, the explosion-proof valve is based on the principle of expansion and rupture of rubber due to an increase in internal pressure of the capacitor. The rubber is selected from those which are resistant to the electrolyte solution inside the capacitor, and have a property of being a thin film and capable of expanding and bursting at a predetermined air pressure. Rubber materials include silicone rubber, butyl rubber, ethylene-propylene diene rubber (EDPM),
Fluororubber is preferred. As a method for vulcanizing butyl rubber,
Peroxide vulcanization is particularly preferred because it has heat resistance and solvent resistance.

The explosion-proof valve has a columnar portion coaxially provided with a hole having a closed end extending from the second flange portion toward the first flange portion, thereby providing a substantially central portion of the first flange portion. In this electric double layer capacitor, the valve differential pressure is 1.5 to 15 k.
g / cm ² .

According to the present invention, after the opening of the metal case is sealed with the upper lid, the opening formed in the upper lid is
Another feature is that the explosion-proof valve is inserted from outside the case. That is, after joining the positive electrode lead and the negative electrode lead of the capacitor element to the positive electrode terminal and the negative electrode terminal provided on the upper lid, respectively, the capacitor element is housed in a metal case, and the opening of the case is sealed with the upper lid, Next, the capacitor is heated and dried under vacuum to remove volatile impurities such as moisture in the capacitor element, and after impregnating the electrolyte with a vacuum, a DC voltage is preliminarily applied to diffuse gas that can be generated from the capacitor in advance. Finally, a capacitor manufacturing process in which an explosion-proof valve is fitted in the through hole of the upper lid can be realized. Therefore, the capacitor heated and dried under vacuum is impregnated with an electrolytic solution and applied with a preliminary voltage in dry air having a dew point of minus 50 ° C. or less, for example.

On the other hand, in the case of the conventional type in which the explosion-proof valve is inserted from the element side, in order to release the gas generated at the time of preliminary voltage application, the upper cover to which the explosion-proof valve is previously attached and the vacuum lid are used. To the lead of the electrode element body of
After the electrode element body is impregnated with the electrolytic solution and the preliminary voltage application is completed, it is necessary to seal the entire opening of the metal case with the upper lid. Therefore, since the sealing machine needs to be used in a dry atmosphere, the manufacturing equipment of the capacitor becomes complicated and expensive, and there is a problem that the productivity is reduced.

The explosion-proof valve in the electric double layer capacitor according to the present invention is particularly effective for a capacitor handling high electric energy having a capacitance of 50 F or more. In a capacitor of 50F or less, since there is little space for providing an explosion-proof valve as in the present invention in the upper lid, and a small amount of gas is released when the valve is operated, a thin-film type explosion-proof valve that does not penetrate into a metal case is rather provided on the upper lid. It can be said that it is preferable to provide them.

In order to increase the withstand voltage of the electric double layer capacitor, a non-aqueous solvent is used as the electrolyte for the electric double layer capacitor of the present invention. In particular, R ¹ R ² R ³
R ⁴ N ⁺ , R ¹ R ² R ³ R ⁴ P ⁺ (however, R ^{1 to} R ⁴
Is an alkyl group having 1 to 5 carbon atoms and may be the same or different) and a quaternary onium cation such as BF ₄ ⁻ , N (CF
_{^{3 SO 2) 2 -, PF}} 6 -, ClO 4 - use of organic electrolyte in combination with the salt and the anion is a low water content is dissolved in an organic solvent and the like are preferable.

The non-aqueous solvent of the electrolytic solution used for the electric double layer capacitor in the present invention includes propylene carbonate, ethylene carbonate, diethyl carbonate,
Solvents composed of at least one selected from dimethoxyethane, butylene carbonate, sulfolane, methylsulfolane, dimethyl carbonate and ethyl methyl carbonate are preferred in view of chemical and electrochemical stability, electrical conductivity and low-temperature characteristics.

The polarizable electrode mainly composed of a carbon material of the electric double layer capacitor of the present invention comprises at least activated carbon, a conductive material for providing electric conductivity, a binder as a binder, and a metal current collector foil. This polarizable electrode can be formed, for example, by the following method.

As one of them, activated carbon powder, carbon black and a binder are mixed with a solvent to form a slurry, which is applied or dipped on a metal current collector foil, dried, pressed if necessary, and integrated with the current collector. There is a method of obtaining a polarized electrode. When producing a positive electrode or a negative electrode made of a carbon material using the slurry, binders added to the slurry include polyvinylidene fluoride, fluoroolefin copolymer, carboxymethyl cellulose, polyvinylpyrrolidone, polyvinyl alcohol and polyacrylic acid. And polyimide are preferably used.

[0021] The solvent of the slurry is preferably one that dissolves these binders, such as N-methylpyrrolidone,
Water, dimethylformamide, toluene, xylene, methyl ethyl ketone, ethyl acetate, methyl acetate, dimethyl phthalate, ethanol, methanol, butanol, water and the like are appropriately selected. Further, the crosslinking agent of the crosslinked polymer includes amines, polyamines, polyisocyanates,
Bisphenols, peroxides and the like can be used.

Instead of the method of applying the slurry, the activated carbon powder, the conductive material powder, and the fluororesin powder as a binder are kneaded while adding a plasticizer, and roll-press molded to form a sheet, and the conductive adhesive is used. It is preferable that the electrode is electrically bonded to an aluminum foil to form a polarizable electrode body because an electric double layer capacitor element having a high capacitance density can be obtained.

As the conductive adhesive, carbon fine particles are preferable because they are inexpensive and electrochemically stable.
An organic binder can be added to strengthen the adhesive force.

The carbon material that can be used in the present invention includes coconut activated carbon, phenol-based activated carbon, petroleum coke-based activated carbon, polycean, and the like. In terms of obtaining a large capacitance, phenol-based activated carbon, petroleum coke-based activated carbon,
The use of polycean is preferred. Examples of the activation method of activated carbon include a steam activation method and a molten KOH activation method. In terms of obtaining a larger capacitance, the molten KO
An H activation treatment method is preferred.

When the carbon material has an average particle diameter of 30 μm or less and a specific surface area of 1500 to 3000 m ² / g, the electric double layer capacitor can have a large capacitance.
In addition, it is preferable because the internal resistance can be reduced.

The amount of the conductive material such as carbon black in the polarizable electrode is preferably 5 to 40% by weight based on the total amount of the activated carbon in order to obtain conductivity. More preferably, 10 to 30 because the capacitance is reduced.
It is recommended to use wt%.

As the conductive material used for the electrode, natural graphite, artificial graphite, metal fiber, titanium oxide, ruthenium oxide and the like can be used in addition to carbon black. The use of chain black or acetylene black is preferred.

Of the metal current collectors used in the present invention, the material of the positive electrode current collector is aluminum or stainless steel 316L.
Is preferred because of its high corrosion resistance. Aluminum is particularly preferred because it is light and has low electric resistance. Examples of the shape of the plate include a foil shape, an expanded metal shape, a fiber sintered body sheet shape, and a plate-shaped metal foam. Among them, a foil shape of 20 to 100 μm is easy to wind or laminate, and is compared. It is preferable because it is cheap.

As the material of the current collector for the negative electrode, aluminum, stainless steel, and nickel can be used, but aluminum is particularly preferable because it is light and has low electric resistance. The shape of the plate is the same as the positive electrode current collector plate, such as a foil-like expanded metal shape, a fiber-sintered body sheet, a plate-like metal foam, etc. Among them, a foil shape of 20 to 100 μm is wound or laminated. It is preferable because it is easy and relatively inexpensive.

In any case, when a metal foil is used for the current collector, if the surface is roughened by a chemical, electrochemical or physical method, the adhesion between the activated carbon electrode layer and the metal foil is improved, and the resistance is increased. This is particularly preferable because it can be reduced.

Examples of the separator used in the present invention include glass fiber mat, cellulose paper made of manila hemp and kraft, hydrophilized porous polytetrafluoroethylene film, and polypropylene nonwoven fabric. Further, aluminum, stainless steel, iron or an alloy thereof is used for the metal case used in the present invention.

The material of the upper lid used in the present invention is exemplified by an aluminum plate, a stainless steel plate or a phenol resin plate, a bakelite plate, a rubber-coated bakelite plate and the like. The thickness of the upper lid is suitably 1 to 10 mm. If it is less than 1 mm, the mechanical strength is insufficient, and the sealing property of the explosion-proof valve is undesirably reduced. If it exceeds 10 mm, the weight of the capacitor becomes excessive, which is not preferable. To increase the strength of the top lid,
Preferably, a rib is formed inside the upper lid. In particular, the thickness of the upper cover near the explosion-proof valve is preferably 1.5 to 8 mm.

In the present invention, a foil-shaped polarizable electrode which has been heated and dried in advance is wound or laminated via a separator to form a capacitor element, and is vacuum-dried at 120 to 250 ° C. to remove volatile components such as moisture from the capacitor element. After that, the electrolytic solution is vacuum impregnated. When the system is heated to 40 to 80 ° C. during the impregnation, the viscosity of the electrolyte decreases, and the electrolyte is quickly impregnated into the activated carbon electrode, which is preferable. After storing the capacitor element in the metal case, it is preferable to impregnate the electrolytic solution in vacuum.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, in order to better understand the technical concept of the present invention, the embodiment shown in FIG. 1 will be described. FIG. 1 is an enlarged sectional view showing a state in which an explosion-proof valve 1 applied to an electric double layer capacitor of the present invention is fitted in a through hole 2 a of an upper lid 2.

Although neither a capacitor element nor a metal case for housing the element is shown in FIG.
The upper lid 2 is fixed to the opening of the metal case by a known method such as caulking. In this case, the upper side of the upper lid 2 is the outer surface of the case, and the lower side is the inner surface of the case.

According to this, the explosion-proof valve 1 is connected to the through hole 2 of the upper lid 2.
a, a first flange portion 12 formed on one end side of the columnar portion 11 so as to be disposed on the outer surface of the case of the upper lid 2, and an upper cover portion on the other end side of the columnar portion 11. And a second flange portion 13 formed to be disposed on the inner side surface of the second case, and the whole thereof is integrally formed of a rubber material such as silicon rubber.

Explaining the dimensions of these portions, the columnar portion 11 has an axial length B substantially equal to the thickness of the upper lid 2, and its outer diameter F is 90 to 120 in the natural state with respect to the inner diameter of the through hole 2a. % Of the size. But Figure 1
Since the columnar portion 11 is inserted into the through hole 2a,
The outer diameter F coincides with the inner diameter of the through-hole, but the natural state is a state in which no load is applied before the columnar portion 11 is inserted into the through-hole 2a. In some cases, an annular rib as a packing material for the through hole 2a may be integrally formed on the outer peripheral surface of the columnar portion 11.

The outer diameter D of the first flange portion 12 is equal to the through hole 2a.
Is in the range of 120 to 400% with respect to the inner diameter. The outer diameter G of the second flange portion 13 is in the range of 110 to 140% with respect to the inner diameter of the through hole 2a. This explosion-proof valve 1
Is to forcibly reduce the diameter of the second flange portion 13 so that the through hole 2a
By pushing it in, it can be attached to the upper lid 2 from the outside of the case.

The columnar portion 11 is provided coaxially with a hole 14 having a closed end having an inner diameter E extending upward from the bottom surface of the second flange portion 13 toward the first flange portion 12 side. A valve portion 15 having an inner diameter E and a thickness H is formed substantially at the center of the first flange portion 12.

The inner diameter E and the thickness H of the valve portion 15 are set according to a desired valve operating pressure. In the present invention, the valve operating pressure is set to 1.5 to 15 kg / cm ² , but when the metal case is square, the operating pressure is preferably set to ² to 5 kg / cm ² . If the metal case is cylindrical, 3-12 kg /
It is preferable to set the working pressure to cm ² .

In any case, the thickness H of the valve portion 15 depends on the mechanical strength of the rubber, but is preferably in the range of 0.05 to 0.8 mm. If the thickness of the valve portion 15 is less than 0.05 mm, the permeation of moisture from the outside increases, which is not preferable. If it exceeds 0.8mm, the valve operating pressure will be 15kg / cm
^2, which does not satisfy the function as an explosion-proof valve.

The inner diameter E of the valve section 15 is preferably in the range of 1 to 4 mm. If the inner diameter is less than 1 mm, molding of the explosion-proof valve becomes difficult, and the valve operating pressure cannot be reduced. On the other hand, if the inner diameter E exceeds 4 mm, the amount of moisture permeation from the outside increases, which is not preferable.

[0043]

【Example】

Example 1 A mixture comprising 80% by weight of phenolic KOH-activated activated carbon powder (specific surface area: 2100 m ² / g, average particle size: 5 μm), 10% by weight of Ketjen Black EC, and 10% by weight of polytetrafluoroethylene powder, Thickness obtained by adding, mixing, kneading, forming and drying ethanol.
A 3 mm electrode sheet was prepared by roughening the surface to a thickness of 100 μ.
m, and bonded to both surfaces of a current collector aluminum foil via a conductive adhesive containing graphite fine powder, then pressed and heat-treated and dried to obtain an effective electrode surface of 10 × 10 cm and a width of 3 c at the upper end.
Thus, a polarizable electrode body sheet having a lead part with a length of 4 cm was obtained.

A positive electrode and a negative electrode made of this electrode body sheet are laminated via a glass fiber mat separator having a thickness of 150 μm, and an insulating resin plate is arranged at both ends of the laminated body. The positive electrode lead aluminum foil and the negative electrode lead aluminum foil are 2 mm thick, 11 cm long,
Ultrasonic bonding was performed on a positive electrode terminal and a negative electrode terminal provided on a rectangular aluminum lid having a width of 3 cm.

The upper lid has a through hole with an inner diameter of 6 mm at the center. The capacitor-top lid integrated element was housed in an aluminum case having a height of 13 cm, a width of 11 cm, and a thickness of 3 cm, and the opening was covered with the upper lid. The periphery of the upper lid was laser-welded to the aluminum case in the atmosphere. The capacitor after welding was vacuum dried at 150 ° C. for 16 hours to remove volatile impurities. Thereafter, a propylene carbonate electrolyte in which 1 mol / liter of (C ₂ H ₅ ) ₃ CH ₃ NBF ₄ was dissolved in a dry air atmosphere having a dew point of −50 ° C. or less was added to the element for 3 minutes.
Vacuum impregnation at 5 ° C.

Then, a 2.7 V DC voltage was applied between the positive terminal and the negative terminal of the device impregnated with the electrolytic solution at 50 ° C. for 20 hours, thereby applying a preliminary voltage. The preliminary applied voltage was 1.08 times the rated voltage. After that, press the explosion-proof valve from the outside of the case into the through hole of the top lid of the capacitor to seal the capacitor, place the heat-shrinkable insulating tube and the vinyl chloride sheet for insulation on the side and bottom of the aluminum case, respectively, to complete the electric double layer capacitor. Completed.

When the characteristics were measured, the electric double layer capacitor had a capacitance of 3300 F and a rated voltage of 2.5 V.
Met. The operating pressure of the explosion-proof valve was 3 kg / cm ² . The explosion-proof valve is made of silicone rubber, and the dimensions of each part will be described with reference to the reference numerals in FIG. 1. A: 2 mm, B: 2 m
m, C: 1.5 mm, D: 12 mm, E: 2 mm, F:
6 mm, G: 8 mm, H: 0.15 mm. In addition,
A and C are the thicknesses of the first and second flange portions 12 and 13, respectively.

Example 2 Phenol-based KOH-activated activated carbon powder (specific surface area: 2000 m ² / g, average particle size: 1)
0 μm) A slurry obtained by adding N-methylpyrrolidone to a mixture comprising 76% by weight, 14% by weight of Ketjen black EC and 10% by weight of polyvinylidene fluoride was mixed with a 30 μm thick aluminum foil having a roughened surface. After coating on both sides and drying at 180 ° C, press to 100μ thickness
m polarizable electrode coils were obtained. Then, four aluminum leads each having a width of 5 mm, a thickness of 150 μm, and a length of 50 mm were joined to a positive electrode and a negative electrode each having a width of 100 mm and a length of 4200 mm, each of which was made of an electrode coil.
m through the separator.

Next, each of these aluminum leads is 5 m thick.
m, a positive electrode terminal and a negative electrode terminal provided on a disk-shaped upper lid made of a phenolic resin having an outer diameter of 50 mm were joined with rivets to obtain a capacitor-top lid integrated element. The upper lid is provided with a through hole having an inner diameter of 6 mm. This capacitor-top lid integrated element is housed in an aluminum case having a height of 12 cm and a diameter of 5 cm, an upper lid is placed over the opening, and a rubber ring is arranged on the periphery thereof. I sealed it off. The sealed capacitor was vacuum-dried at 130 ° C. for 16 hours to remove volatile impurities.

Thereafter, under a dry air atmosphere having a dew point of −50 ° C. or less, 1 mol / liter of (C ₂ H ₅ ) ₃ CH ₃ NB
This device was vacuum impregnated with a propylene carbonate electrolyte in which F ₄ was dissolved at 35 ° C. A DC voltage of 2.6 V was applied between the positive terminal and the negative terminal of the capacitor impregnated with the electrolytic solution at 50 ° C. for 20 hours to apply a preliminary voltage.

An explosion-proof valve is pushed into the through hole of the upper lid of the capacitor from the outside of the case to seal the capacitor, and an insulating heat-shrinkable tube and an insulating vinyl chloride sheet are arranged on the side and bottom of the aluminum case, respectively. The capacitor was completed.

When the characteristics were measured, the capacitance of this electric double layer capacitor was 1700 F and the rated voltage was 2.5 V
Met. The operating pressure of the explosion-proof valve was 8 kg / cm2. Explosion-proof valve is made of peroxide-cured butyl rubber,
Explaining the dimensions of each part in the same manner as in Example 1, A: 3 m
m, B: 6 mm, C: 1.5 mm, D: 10 mm, E:
2 mm, F: 6 mm, G: 8 mm, H: 0.4 mm.

[0053]

As described above, according to the present invention,
An electric double layer capacitor for power handling high electric energy provided with an explosion-proof valve which is highly reliable in operation, inexpensive and has good productivity is provided.

Further, according to the present invention, the explosion-proof valve can be attached from the outside of the case to the through hole formed in the upper lid as a sealing member. Can be simplified.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing a state in which an explosion-proof valve applied to an electric double layer capacitor of the present invention is attached to an upper lid as a sealing member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Explosion-proof valve 2 Top cover 2a Through-hole 11 Column-shaped part 12 1st flange part 13 2nd flange part 14 Hole with which end was closed 15 Valve part

 ──────────────────────────────────────────────────の Continuing on the front page (72) Ken Ken Kawari 1150 Hazawa-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Inside the Central Research Laboratory of Asahi Glass Co., Ltd. Central Research Laboratory

Claims (4)

[Claims] A positive electrode and a negative electrode each provided with a polarizable electrode layer made of a carbon material, a conductive material and a binder on a metal current collector plate are wound or laminated with a separator interposed therebetween to impregnate an organic electrolyte. An electric double-layer capacitor in which a capacitor element is housed in a bottomed cylindrical metal case, the opening of which is sealed with an upper lid, and an explosion-proof valve is fitted in a through hole formed in the upper lid. The explosion-proof valve is inserted into the through-hole and has a diameter of 90 to 120 with respect to the inner diameter of the through-hole.
% And an outer diameter of 120 to 400% with respect to the inner diameter of the through-hole, and formed at one end of the columnar portion on the outer surface of the case of the upper lid. The first flange portion, and 1 to the inner diameter of the through hole.
A second flange portion having an outer diameter of 10 to 140% and formed at the other end side of the columnar portion so as to be disposed on the inner side surface of the case of the upper lid; A hole whose end extending from the flange portion side toward the first flange portion side is closed is provided coaxially,
An electric double layer capacitor, wherein a valve portion is formed at a substantially central portion of the first flange portion by the hole. 2. The explosion-proof valve according to claim 1, wherein the material of the explosion-proof valve is any one of silicon rubber, butyl rubber, ethylene-propylene-diene rubber, and fluorine rubber, and has a capacitance of 50 F or more. Electric double layer capacitor. 3. The valve differential pressure of the valve section is 1.5 to 15 kg.
The electric double layer capacitor according to claim 1, wherein the electric double layer capacitor is in a range of / cm ² . 4. A positive electrode and a negative electrode each provided with a polarizable electrode layer made of a carbon material, a conductive material and a binder on a metal current collector plate are wound or laminated via a separator, and impregnated with an organic electrolyte. After storing the capacitor element in a bottomed cylindrical metal case and closing the opening with an upper lid, when fitting the explosion-proof valve to a through hole formed in the upper lid, the explosion-proof valve is A columnar portion inserted into the through hole and having an outer diameter of 90 to 120% with respect to the inner diameter of the through hole; and a columnar portion having an outer diameter of 120 to 400% with respect to the inner diameter of the through hole. A first flange portion formed at one end side of the portion so as to be disposed on the outer surface of the case of the upper lid, having an outer diameter of 110 to 140% with respect to the inner diameter of the through hole; On the inner side of the case at the end A second flange portion formed so that the second flange portion is formed substantially coaxially with the columnar portion, and a valve portion formed substantially at the center of the first flange portion by a hole provided coaxially with the columnar portion. Characterized in that the explosion-proof valve is fitted into the through hole of the upper lid from the outer surface side of the upper lid.