JP2015088703A - Separator for capacitors, and capacitor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a separator which is superior in tensile strength and tear strength, and enables the achievement of high shieldability and low ESR; and an electric double layer capacitor which enables, by using such a separator, the increase in productivity without affecting an internal resistance and a leakage current property.SOLUTION: A separator for electric double layer capacitors has a double layer structure which has a fiber layer A produced by papermaking with a long or short length of wire cloth, and composed of a layer having a CSF value of 50-0 ml, a density of 0.25-0.70 g/cmand a thickness of 5-145 μm, and a fiber layer B produced by papermaking with a cylinder mold, and composed of a layer having a CSF value of 600-10 ml, a density of 0.15-0.50 g/cmand a thickness of 5-145 μm. The fiber layer A and the fiber layer B include 10 wt.% or more of regenerated cellulose fiber which can be beaten. The whole separator has a density of 0.2-0.6 g/cmand a thickness of 10-150 μm, which allows the separator to have a mechanical strength strong enough to avoid suffering the fracture thereof in winding and laminating steps, and which enables the achievement of high shieldability and low ESR. An electric double layer capacitor comprises the separator for electric double layer capacitors.

Description

  The present invention relates to a capacitor separator and a capacitor using the separator, for example, a capacitor separator suitable for an electric double layer capacitor and a capacitor using the separator.

  An electric double layer capacitor is a capacitor that utilizes the electric double layer phenomenon in which charges are accumulated between the polarizable electrode surface and the electrolyte interface when the polarizable electrode is brought into contact with the electrolyte solution. A pair of polarizable electrodes facing each other, and a separator and an organic electrolyte that electrically and mechanically isolate the pair of polarizable electrodes. As the polarizable electrode, activated carbon powder having a large charge storage interface, that is, a large specific surface area is used.

  This electric double layer capacitor has a large electrode area and can be obtained with a much larger capacity than aluminum electrolytic capacitors, which are recognized as having a large capacity among capacitors, so it is mainly used for memory backup of household appliances. Has been used for. In recent years, attention has been focused on large-capacity electric double layer capacitors, and their use has been expanded to various applications such as vehicles, solar and wind power generation, in addition to OA equipment and industrial machinery.

  The electric double layer capacitor includes a coin type, a wound type, and a laminated type according to the structure, and the capacitance is determined by the surface area of the electrode that acts as a charge storage interface.

In the coin type, fine activated carbon fiber or activated carbon powder is bound with a binder, and a separator interposed between a pair of polarizable electrodes punched in a circular shape in a mat is impregnated with an electrolytic solution. It is housed in a metal case that also serves as an exterior material and a metal lid, and is sealed by caulking through a gasket.

  In the wound type, in order to increase the surface area of the electrode material, the activated carbon made into fine powder is coated and bonded to the surface of the metal foil as a current collector with a binder, and this electrode pair is separated from the separator. A capacitor element is wound by interposing and impregnated with an electrolytic solution, and then housed in a metal case and sealed.

In the laminated type, electrodes and separators are alternately laminated to form a capacitor element, which is housed in a metal case or a laminate film, injected with an electrolytic solution, and sealed.

  As a large-capacity electric double layer capacitor whose use has been expanding in recent years, a wound type or multilayer type structure is adopted. The large-capacity type is used for regenerative energy such as vehicles or for wind and solar power generation systems with large load fluctuations. In this application, it excels in instantaneous charge and discharge, which is a feature of electric double layer capacitors, and has a long cycle life. Characteristics are required.

  For this purpose, it is essential to reduce the resistance of the electric double layer capacitor. When the internal resistance is high, when charging / discharging a large current in a short time, heat is generated due to loss due to the resistance, and performance deterioration proceeds due to the influence of the generated heat. In order to reduce the resistance of electric double layer capacitors, various members such as electrode materials and electrolytes have been actively improved. However, as a separator, there is a strong demand for reducing the resistance of the separator itself.

In addition, as the market expands due to the expansion of applications of electric double layer capacitors, the separator has the strength to improve productivity without adversely affecting the internal resistance and leakage current characteristics in order to improve productivity. There is a need for a separator.

  Examples of separators suitable for conventional wound-type and multilayer electric double-layer capacitors include regenerated cellulose fiber separators described in Patent Document 1, layers containing regenerated cellulose fibers described in Patent Document 2, and polyolefin porous membranes There are two-layer separators and the like in which layers are laminated.

JP 2000-3834 A JP 2011-35373 A

  However, when the separator is composed of 100% by weight of regenerated cellulose fiber that can be beaten as in Patent Document 1, the tear strength is drastically reduced due to excessive increase of hydrogen bonds between the fibers, so There is a problem that the separator breaks in the manufacturing process of the type electric double layer capacitor.

  This is considered to be due to the following reason. Sheets made with fine fibrils of several tens of nanometers to several micrometers obtained by highly advanced beating of regenerated cellulose fibers that can be beaten form a very dense paper layer, and the rigidity of the fibrils. Therefore, the sheet is excellent in ESR characteristics. Moreover, since the hydrogen bond between fibers increases when the fibril increases, the value of tensile strength can be increased.

However, on the other hand, the tear strength gives a maximum value with a very slight increase in fiber-to-fiber bond, and the tear strength decreases rather sharply with further increase in fiber-to-fiber bond. That is, the tensile strength due to the bond between fibers and the tear strength are in a reciprocal relationship, and the higher the beating, the higher the tensile strength, but the lower the tear strength.
On the other hand, if beating is suppressed in order to improve the tear strength, not only the tensile strength but also the shielding property is lowered, which causes a problem that the leakage current value of the electric double layer capacitor becomes large.

  In addition, as in Patent Document 2, a separator having excellent mechanical strength has been proposed by using a double-layer separator in which a polyolefin porous membrane layer is laminated on a layer obtained by mixing chemical fibers with regenerated cellulose fibers. However, since the porous polyolefin membrane has fewer voids than the cellulose separator, there is a problem that the ionic conductivity of the electrolytic solution is inhibited and ESR deteriorates.

  The present invention has been made in view of the above problems, and provides a capacitor separator that is excellent in tensile strength and tear strength, and that can achieve high shielding properties and low ESR, or by using the separator, internal resistance, It is an invention made for the purpose of providing a capacitor, such as an electric double layer capacitor, capable of improving productivity without adversely affecting the leakage current characteristics.

As a means for solving the above-described problems and achieving the above-described object, an embodiment of the present invention according to the present invention has the following configuration, for example.
That is, a separator for a capacitor that is interposed between a pair of polarizable electrodes and can hold an electrolyte-containing electrolyte solution, which is a fiber layer A made of a long mesh or a short mesh, and a fiber layer made of a circular mesh The fiber layer A and the fiber layer B contain 10% by weight or more of regenerated cellulose fibers that can be beaten, and the density of the entire two-layer structure is 0.2 to 0.6 g. / cm ³ and a thickness of 10 to 150 μm.

And, for example, a capacitor separator interposed between a pair of polarizable electrodes and capable of holding an electrolyte-containing electrolyte solution, which is made of a fiber layer A made of a long mesh or a short mesh, and made of a circular mesh. The fiber layer A and the fiber layer B contain 10% by weight or more of regenerated cellulose fibers that can be beaten, and the density of the entire two-layer structure is 0.2 to 0.2%. It is 0.6 g / cm ³ and has a thickness of 20 to 60 μm.

Further, for example, the fiber layer A and the fiber layer B contain 60% by weight or more of regenerated cellulose fibers that can be beaten.
Further, for example, the beaten regenerated cellulose fiber is selected from solvent-spun rayon fiber or viscose regenerated cellulose fiber.

For example, the fiber layer A contains regenerated cellulose fibers beaten to 50 to 0 ml of CSF, and has a density of 0.25 to 0.70 g / cm ³ and a thickness of 5 to 145 μm.
Further, for example, the fiber layer A contains regenerated cellulose fibers beaten to CSF 50 to 0 ml, has a density of 0.25 to 0.70 g / cm ³ and a thickness of 10 to 50 μm.

For example, the fiber layer B contains regenerated cellulose fibers beaten to CSF 600 to 10 ml, has a density of 0.15 to 0.50 g / cm ³ and a thickness of 5 to 145 μm.
Further, for example, the fiber layer B contains regenerated cellulose fibers beaten to CSF 600 to 10 ml, has a density of 0.15 to 0.50 g / cm ³ and a thickness of 10 to 50 μm.

Further, for example, the capacitor is characterized by using a capacitor separator as described above.
For example, the capacitor is an electric double layer capacitor or a lithium ion capacitor.

  ADVANTAGE OF THE INVENTION According to this invention, the separator which is excellent in both tensile strength and tear strength, and can implement | achieve low ESR and high shielding property can be provided. Further, by using the separator, it is possible to provide a capacitor capable of improving productivity without adversely affecting internal resistance and leakage current characteristics, for example, an electric double layer capacitor.

  Hereinafter, an embodiment of the invention according to the present invention will be described in detail with reference to tables and the like. The present embodiment can provide a capacitor and an electric double layer capacitor that can improve productivity without adversely affecting internal resistance and leakage current characteristics. In the following description, an example in which an electric double layer capacitor is used as a capacitor that uses the separator of this embodiment will be described. However, application to other capacitors is not excluded.

  In addition to the examples shown in the present embodiment and examples, as a result of testing and research on various materials and composition ratios, it contains 10% by weight or more of regenerated cellulose fibers that can be beaten, and the paper is made with a long or short mesh. It has been found that a good result can be obtained by forming a two-layer structure of the fiber layer A and the fiber layer B made with a circular net.

  By having the fiber layer A paper-made with a long or short mesh and the fiber layer B paper-made with a circular mesh, it becomes possible to achieve both tensile strength and tear strength, which are reciprocal relationships, By using a regenerated cellulose fiber beating raw material that can be beaten as the fiber material, it becomes easy to improve the shielding properties without deteriorating the internal resistance.

  Furthermore, by making the paper layer structure into two layers, it is possible to increase the shielding without deteriorating the internal resistance, so even when mixing other fiber materials, while suppressing the deterioration of the internal resistance, Sheet holes can be prevented.

  In the electric double layer capacitor using the separator of this embodiment, the separator portion is impregnated and held with an organic electrolyte, and a pair of polarizable electrodes are separated by the separator to form an electric double layer capacitor.

[Description of separator]
The separator according to the present embodiment uses a raw material obtained by beating regenerated cellulose fibers that can be beaten, or other raw materials, by using a long mesh paper machine, a short mesh paper machine, etc. A paper layer formed of a short mesh and a paper layer formed of a circular mesh are combined on-machine to form a two-layer separator. It is also preferable to produce a separator by laminating two separators made by a long net paper machine and a circular net paper machine, or a short net paper machine and a circular net paper machine by an off-machine.

  The content of the beating raw material of the regenerated cellulose fiber that can be beaten is preferably 10% by weight or more, more preferably 60% by weight or more. When the content of the beating raw material of the regenerated cellulose fiber is less than 10% by weight, the amount of other fibers increases, resulting in deterioration of the shielding property of the separator and a large leakage current value of the electric double layer capacitor. There is a risk.

  For the regenerated cellulose fiber, a solution obtained by dissolving cellulose on a molecule with an organic solvent such as copper ammonia regenerated cellulose fiber, viscose regenerated cellulose fiber, and N-methylmorpholine-N-oxide by a wet spinning method. Solvent-spun recycled cellulose fibers. Among them, typical examples of regenerated cellulose fibers that can be beaten include polynosic rayon as viscose regenerated cellulose fiber, and lyocell as solvent-spun rayon fiber, and these regenerated cellulose fibers can be easily used. Layers can be formed.

  The fiber diameter of fibrils obtained by beating regenerated cellulose fibers is small, and the bonding strength between fibers is weak. For this reason, the fibers are bound at the entanglement point, but the internal resistance is not deteriorated because the fibers are not in close contact with each other at the surface or line. In the present embodiment, this characteristic point is the reason for blending regenerated cellulose fibers that can be beaten. However, the present invention is not limited to the above example, and any regenerated cellulose fiber that can be beaten may be used. For example, it is not limited to polynosic rayon fiber and lyocell fiber, which are described in detail below.

  As other fibers mixed in the beating raw material, it is required that internal resistance is not deteriorated and short-circuit failure does not occur when incorporated in an electric double layer capacitor. Therefore, although there is no particular limitation, natural cellulose fibers such as hemp pulp, manila hemp pulp, esparto pulp, wood craft pulp, cotton pulp, etc. can be used. Ultrafine fibers such as polyethylene, polyethylene terephthalate, polyphenylene sulfide, polyethylene naphthalate, and aramid may be selected.

The density of the two-layer separator is preferably 0.20 to 0.60 g / cm ³ . This is because if the density of the separator is less than 0.20 g / cm ³ , the tensile strength and tear strength of the separator are weak, and the separator may break during winding or lamination. Further, when the density of the separator is less than 0.20 g / cm ³ , the shielding property of the separator is low, and therefore, when applied to an electric double layer capacitor, the leakage current value becomes large. Furthermore, if the density of the separator exceeds 0.60 g / cm ³ , the strength of the separator is sufficient, but the gap of the separator is reduced and the ion permeability is inhibited, and the internal resistance of the electric double layer capacitor is deteriorated. This is because a problem arises.

  Moreover, as thickness of a two-layer separator, it is preferable that it is 10-150 micrometers, and 20-60 micrometers is more preferable. When the thickness of the separator is less than 10 μm, the tensile strength and tear strength of the separator are weak, the separator may be broken during winding or lamination, and the shielding performance of the separator is low. This is because it becomes a multilayer capacitor. Furthermore, if the thickness of the separator exceeds 150 μm, the strength of the separator is sufficient, but since the shielding property becomes too high due to the thick separator, the problem arises that the internal resistance of the electric double layer capacitor deteriorates. It is.

  As the beating degree of the fiber layer A, it is preferable that the beating raw material be beaten to 50 to 0 ml of CSF. If the CSF is larger than 50 ml, the tensile strength of the separator is weak, and the separator may break during winding or lamination. In addition, the electric double layer capacitor is not sufficiently shielded and has a large leakage current value.

The density of the fiber layer A is preferably 0.25 to 0.70 g / cm ³ . When the density of the fiber layer A is less than 0.25 g / cm ³ , the separator has a low tensile strength, so that the separator may be broken during winding or lamination, and the shielding property of the separator is low. This is because the electric double layer capacitor becomes large. On the other hand, if the density of the fiber layer A exceeds 0.70 g / cm ³ , the gap of the separator is reduced and the ion permeability is hindered, resulting in a problem that the internal resistance of the electric double layer capacitor is deteriorated. is there.

As thickness of the fiber layer A, 5-145 micrometers is preferable, More preferably, 10-50 micrometers is preferable. When the thickness of the fiber layer A is less than 5 μm, the tensile strength of the separator is weak, so that the separator may be broken during winding or lamination, and the shielding property of the separator is low. It becomes a multilayer capacitor.
On the other hand, when the thickness of the fiber layer A exceeds 145 μm, the shielding property becomes excessively high due to the thick separator, which causes a problem that the internal resistance of the electric double layer capacitor is deteriorated.

  As the beating degree of the fiber layer B, it is preferable that the beating raw material be beaten to 600 to 10 ml of CSF. When the CSF is larger than 600 ml, there are many unbeaten fibers, and since the fiber-to-fiber bond does not reach the level that expresses the tear strength, the sheet has a low tear strength. If the CSF is less than 10 ml, the tearing strength is lowered by excessively increasing the hydrogen bonds between the fibers by proceeding the beating, so that the separator may break during winding or lamination, Productivity at the time of manufacturing the electric double layer capacitor is lowered.

The density of the fiber layer B is preferably 0.15 to 0.50 g / cm ³ . When the density of the fiber layer B is less than 0.15 g / cm ³ , the tear strength of the separator is weak, so that the separator may break during winding or lamination. When the density of the fiber layer B exceeds 0.50 g / cm ³ , the tear strength is lowered due to excessive increase of hydrogen bonds between the fibers due to the progress of beating to increase the density. The separator may break during winding or stacking, resulting in low productivity when manufacturing the electric double layer capacitor.

  As thickness of the fiber layer B, 5-145 micrometers is preferable, More preferably, 10-50 micrometers is preferable. If the thickness of the fiber layer B is less than 5 μm, the tear strength of the separator is weak, so that the separator may break during winding or lamination. When the thickness of the fiber layer B exceeds 145 μm, since the shielding property becomes too high due to the thick separator, the internal resistance of the electric double layer capacitor is deteriorated.

  With the separator configuration described above, a good separator was found in both the manufacturing process of the electric double layer capacitor and the capacitor characteristics. That is, it is a good separator having both tensile strength and tear strength that can be produced without breaking during winding and lamination, and also has electrical characteristics as an electric double layer capacitor.

[Evaluation method of separator]
Specific measurement of each characteristic of the separator and electric double layer capacitor according to the present embodiment is performed under the following conditions and methods.

[Measurement of thickness]
It was measured by the method specified in “JIS C 2300-2“ Electric Cellulose Paper—Part 2: Test Method ”5.1 Thickness”.

(Measurement of density)
The density in an absolutely dry state was measured by a method defined in Method B of “JIS C 2300-2“ Electric Cellulose Paper—Part 2: Test Method ”7.0 A Density”.

[Measurement of tensile strength]
It was measured by the method prescribed in “JIS C 2300-2“ Electric Cellulose Paper—Part 2: Test Method ”, 8 Tensile Strength and Elongation”.

(Measurement of tear strength)
It was measured by the method specified in “JIS C 2300-2“ Electric Cellulose Paper—Part 2: Test Method ”9 Tearing Strength”. Measurement was performed in a state where 16 test pieces were stacked, and the unit was expressed as gf · 16 pieces.

[Measurement of ESR]
The separator was punched to 38 mmφ, a test piece was collected, impregnated with a predetermined electrolyte, sandwiched between 38 mmφ electrodes, measured by an LCR meter at a frequency of 20 ° C. and 1 kHz, and the unit was expressed in Ω.

[Measurement of airtightness]
According to the method prescribed in JIS P 8117, measurement was performed with a B-type tester (Gurley densometer). However, an adapter having a hole diameter of 6 mmΦ was used because measurement of a separator having a low air density was used. In the measurement, a test piece was sandwiched between adapters and fixed to a measurement port portion of a B-type tester, and the time required for 100 ml of air to pass through was measured. The unit was expressed in sec / 100 ml.

[Production of electric double layer capacitor using separator]
An example in which the separator of this embodiment is applied to an electric double layer capacitor will be described below.
As an electrode of the electric double layer capacitor of the present embodiment, for example, a powdered activated carbon is used as a conductive auxiliary agent to form a sheet using a binder, or activated carbon fiber obtained by activated carbonization of phenol fiber is used as a metal foil. Although formed and used on the surface, the electrode used in this embodiment is not limited to the above example, and the same electrode can be used as appropriate.

  As the electrolytic solution, a quaternary ammonium salt such as tetraethylammonium tetrafluoroborate or triethylmethylammonium tetrafluoroborate as an electrolyte and a solution dissolved in a nonaqueous polar solvent such as propylene carbonate is mainly used. The withstand voltage in the system using this electrolytic solution is about 2.3 to 2.7V.

[Production method of electric double layer capacitor]
Hereinafter, a method for manufacturing an electric double layer capacitor using the separator of this embodiment will be described.
After impregnating the electrolytic solution into a cylindrically wound element with a separator cut into a predetermined width between a pair of polarizable electrodes, accommodated in a bottomed cylindrical aluminum case, and The opening of the aluminum case was sealed with a rubber seal to produce a wound type electric double layer capacitor.

[Evaluation method of electric double layer capacitor]
A wound type electric double layer capacitor (10 mmφ × 35 mmL) with a rated voltage of 2.5 V and a rated capacity of 10 F was manufactured, and capacitance (C), internal resistance (Z), and leakage current (LC) were measured as capacitor characteristics. .

Specific examples relating to the separator according to the embodiment of the present invention described above will be described.
For the separator of this example, a regenerated cellulose was used to produce a wet nonwoven fabric with a long mesh paper machine and a short mesh paper machine to form a sheet as a separator. That is, the separator was composed of a wet nonwoven fabric.

Example 1 and Example 2 below are examples in which the fiber layer A is manufactured in place of the long mesh paper machine (Example 1) and the short mesh paper machine (Example 2).
[Example 1]
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.50 g / cm ³ composed of a raw material beaten up to CSF 0 ml, and the fiber layer B made with a circular mesh is beaten up to CSF 100 ml The layer is made of raw materials and has a thickness of 15 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.38 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

[Example 2]
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a short mesh paper machine. The fiber layer A made with a short mesh is a layer having a thickness of 15 μm and a density of 0.50 g / cm ³ composed of a raw material beaten to 0 ml of CSF. The layer is made of raw materials and has a thickness of 15 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.38 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

The following Examples 3 to 5 are examples in which the composition of the separator raw material is changed.
Example 3
As a papermaking material, 10% by weight of lyocell fiber, which is a regenerated cellulose fiber, and 90% by weight of hemp, which is a natural fiber, were mixed, and a separator was produced with a long net paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.50 g / cm ³ composed of a raw material beaten up to CSF 0 ml, and the fiber layer B made with a circular mesh is beaten up to CSF 100 ml. The layer is made of raw materials and has a thickness of 15 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.38 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Example 4
As a papermaking raw material, 60% by weight of lyocell fiber, which is a regenerated cellulose fiber, and 40% by weight of hemp, which is a natural fiber, were mixed, and a separator was produced with a long net paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.50 g / cm ³ composed of a raw material beaten up to CSF 0 ml, and the fiber layer B made with a circular mesh is beaten up to CSF 100 ml The layer is made of raw materials and has a thickness of 15 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.38 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Example 5
100% by weight of polynosic rayon fiber, which is a regenerated cellulose fiber, was used as a papermaking material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.50 g / cm ³ composed of a raw material beaten up to CSF 0 ml, and the fiber layer B made with a circular mesh is beaten up to CSF 100 ml. The layer is made of raw materials and has a thickness of 15 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.38 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Examples 6 to 11 are examples in which the separator density was changed by changing the beating degree (CSF).
Example 6
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.26 g / cm ³ composed of a raw material beaten to CSF 50 ml, and the fiber layer B made with a circular mesh is beaten to CSF 100 ml. The layer is made of raw materials and has a thickness of 15 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.26 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Example 7
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.26 g / cm ³ composed of a raw material beaten to CSF 50 ml, and the fiber layer B made with a circular mesh is beaten to 600 ml CSF. It is a layer made of raw materials and having a thickness of 15 μm and a density of 0.17 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.22 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Example 8
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.26 g / cm ³ composed of a raw material beaten up to CSF 50 ml, and the fiber layer B made with a circular mesh was beaten up to 15 ml CSF. It is a layer made of raw materials and having a thickness of 15 μm and a density of 0.45 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.36 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Example 9
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long net is a layer having a thickness of 15 μm and a density of 0.68 g / cm ³ composed of a raw material beaten to 0 ml of CSF, and the fiber layer B made of paper with a round net was beaten to 15 ml of CSF. It is a layer made of raw materials and having a thickness of 15 μm and a density of 0.45 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.57 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Example 10
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.50 g / cm ³ composed of a raw material beaten to 0 ml of CSF. It is a layer made of raw materials and having a thickness of 15 μm and a density of 0.17 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.34 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Example 11
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.50 g / cm ³ composed of a raw material beaten up to CSF 0 ml. It is a layer made of raw materials and having a thickness of 15 μm and a density of 0.45 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.48 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

The following Examples 12 to 17 are examples when the thickness of the separator is changed.
Example 12
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long net is a layer having a thickness of 5 μm and a density of 0.50 g / cm ³ composed of a raw material beaten to 0 ml of CSF, and the fiber layer B made of a paper with a round net was beaten to 100 ml of CSF. The layer is made of raw materials and has a thickness of 5 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 10 μm and a density of 0.38 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Example 13
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 145 μm and a density of 0.50 g / cm ³ composed of a raw material beaten to 0 ml of CSF. The layer is made of raw materials and has a thickness of 5 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 150 μm and a density of 0.49 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Example 14
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long net is a layer having a thickness of 5 μm and a density of 0.50 g / cm ³ composed of a raw material beaten up to CSF 0 ml. The layer is composed of raw materials and has a thickness of 145 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 150 μm and a density of 0.26 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Example 15
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 10 μm and a density of 0.50 g / cm ³ composed of a raw material beaten up to CSF 0 ml, and the fiber layer B made with a circular mesh is beaten up to CSF 100 ml It is a layer made of raw materials and having a thickness of 10 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 20 μm and a density of 0.38 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Example 16
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 10 μm and a density of 0.50 g / cm ³ composed of a raw material beaten up to CSF 0 ml, and the fiber layer B made with a circular mesh is beaten up to CSF 100 ml. It is a layer made of raw materials and having a thickness of 50 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 60 μm and a density of 0.29 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Example 17
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 50 μm and a density of 0.50 g / cm ³ composed of a raw material beaten up to CSF 0 ml, and the fiber layer B made with a circular mesh is beaten up to CSF 100 ml. It is a layer made of raw materials and having a thickness of 10 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 60 μm and a density of 0.46 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Comparative Example 1 is an example in which the composition of the separator raw material corresponding to Example 3 was changed.
[Comparative Example 1]
As a papermaking material, 5% by weight of lyocell fiber, which is a regenerated cellulose fiber, and 95% by weight of hemp, which is a natural fiber, were mixed, and a separator was produced with a long net paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.50 g / cm ³ composed of a raw material beaten up to CSF 0 ml, and the fiber layer B made with a circular mesh is beaten up to CSF 100 ml. The layer is made of raw materials and has a thickness of 15 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.38 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Comparative Examples 2 to 6 correspond to Examples 6 to 11 and are examples in which the beating degree (CSF) is changed and the separator density is changed.
[Comparative Example 2]
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.21 g / cm ³ composed of a raw material beaten to CSF 100 ml, and the fiber layer B made with a circular mesh is beaten to 100 ml CSF. The layer is made of raw materials and has a thickness of 15 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.23 g / cm ³ was obtained. Next, an attempt was made to produce a 2.5 V 10 F electric double layer capacitor using this separator. However, the separator was broken by winding the element, and an electric double layer capacitor for evaluation could not be produced.

[Comparative Example 3]
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.21 g / cm ³ composed of a raw material beaten up to CSF 100 ml. It is a layer made of raw materials and having a thickness of 15 μm and a density of 0.12 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.17 g / cm ³ was obtained. Next, an attempt was made to produce a 2.5 V 10 F electric double layer capacitor using this separator. However, the separator was broken by winding the element, and an electric double layer capacitor for evaluation could not be produced.

[Comparative Example 4]
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.80 g / cm ³ composed of a raw material beaten to 0 ml of CSF, and the fiber layer B made of a paper with a mesh was beaten to 15 ml of CSF. It is a layer made of raw materials and having a thickness of 15 μm and a density of 0.45 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.63 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

[Comparative Example 5]
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.50 g / cm ³ composed of a raw material beaten to 0 ml of CSF. It is a layer made of raw materials and having a thickness of 15 μm and a density of 0.12 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.31 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

[Comparative Example 6]
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 15 μm and a density of 0.50 g / cm ³ composed of a raw material beaten up to CSF 0 ml, and the fiber layer B made with a circular mesh is beaten up to CSF 0 ml The layer is made of raw materials and has a thickness of 15 μm and a density of 0.53 g / cm ³ . As a total of the two layers, a separator having a thickness of 30 μm and a density of 0.52 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

Comparative Examples 7 to 9 correspond to Examples 12 to 17 and are examples in which the thickness of the separator is changed.

[Comparative Example 7]
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long net is a layer having a thickness of 3 μm and a density of 0.50 g / cm ³ composed of a raw material beaten to 0 ml of CSF. It is a layer made of raw materials and having a thickness of 3 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 6 μm and a density of 0.38 g / cm ³ was obtained. Next, an attempt was made to produce a 2.5 V 10 F electric double layer capacitor using this separator. However, the separator was broken by winding the element, and an electric double layer capacitor for evaluation could not be produced.

[Comparative Example 8]
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long mesh is a layer having a thickness of 155 μm and a density of 0.50 g / cm ³ composed of a raw material beaten to CSF 0 ml, and the fiber layer B made with a circular mesh is beaten to CSF 100 ml. The layer is made of raw materials and has a thickness of 5 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 160 μm and a density of 0.49 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

[Comparative Example 9]
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking raw material, and a separator was produced with a long mesh paper machine. The fiber layer A made with a long net is a layer having a thickness of 5 μm and a density of 0.50 g / cm ³ composed of a raw material beaten up to CSF 0 ml. It is a layer made of raw materials and having a thickness of 155 μm and a density of 0.25 g / cm ³ . As a total of the two layers, a separator having a thickness of 160 μm and a density of 0.26 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

[Conventional example 1]
100% by weight of lyocell fiber, which is a regenerated cellulose fiber, was used as a papermaking material, and a separator was produced with a long net paper machine. A separator having a thickness of 30 μm and a density of 0.50 g / cm ³ made of a raw material beaten to CSF 0 ml was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

[Conventional example 2]
As a papermaking raw material, 80% by weight of lyocell fiber, which is a regenerated cellulose fiber, and 20% by weight of PET fiber, which is a chemical fiber, are mixed with a fiber layer A manufactured by a standard hand-drawing device specified in JIS P822, and polyethylene. The fiber layer B manufactured with the film manufacturing machine was laminated | stacked by using as a raw material, and the two-layer separator was obtained. The fiber layer B is obtained by melt-extruding a high-density polyethylene (specific gravity: 0.96) with a T-die to form a film, passing through heat treatment in a hot-air circulating oven, and then stretching between nip rolls. The fiber layer A made with a long net is a layer of 10 μm thickness and a density of 0.50 g / cm ³ composed of raw materials beaten to 0 ml of CSF, and the fiber layer B manufactured by a film manufacturing machine has a thickness of 15 μm. The layer has a density of 0.50 g / cm ³ . As a total of the two layers, a separator having a thickness of 25 μm and a density of 0.50 g / cm ³ was obtained. Next, an electric double layer capacitor of 2.5 V 10 F was manufactured using this separator.

  Table 1 shows the measurement results of the separator of the present embodiment having the above configuration, the separators of Comparative Examples 1 to 9, and the separators of Conventional Examples 1 and 2. Regarding the items of the separator rupture of the wound type EDLC manufacturing process of Table 1, the case where the separator can be wound without breaking is ○, the separator can be wound, △ when the break may occur, Δ, when the separator is not broken due to the break X is shown.

As shown in Table 1, in the element winding process of the electric double layer capacitor, the separator of the present embodiment is such that when the electric double layer capacitor is manufactured, the separator is broken by winding the element. There were no failures.
In addition, the performance of the electric double layer capacitor was good even when compared with that using a conventional separator.

In Example 1 and Example 2, the separator characteristics according to the papermaking format of the separator and the electric double layer capacitor characteristics were compared.
As shown in the measurement results of Table 1, the separator has a tensile strength of 10 N / 15 mm or more by using a two-layer structure of a fiber layer A made by a long or short mesh and a fiber layer B made by a circular mesh. The tear strength was 20 gf · 16 or more, and when the electric double layer capacitor was produced, there were no problems such as breakage of the separator during element winding.

  In addition, the ESR is 0.855Ω in Example 1 and 0.853Ω in Example 2, and the airtightness is 151 sec / 100 ml in Example 1 and 147 Sec / 100 ml in Example 2, which shows high shielding properties. The internal resistance of the electric double layer capacitor is 81 mΩ in Example 1, 79 mΩ in Example 2, and the leakage current is 369 μA in Example 1 and 373 μA in Example 2.

In Example 3, Example 4 and Comparative Example 1, the separator characteristics and the electric double layer capacitor characteristics were compared by mixing the raw materials of the separator.
As shown in the measurement results of Table 1, in Example 3 in which 10% by weight of lyocell and 90% by weight of hemp were mixed, the separator had excellent tensile strength of 20.6 N / 15 mm and tear strength of 189 gf · 16 sheets. When the electric double layer capacitor was manufactured, there was no inconvenience such as breakage of the separator during element winding. Although the ESR is as low as 0.998Ω and the airtightness is as high as 101 sec / 100 ml, the electric double layer capacitor has a low internal resistance of 193 mΩ and a leakage current of 441 μA.

  In Example 4 where 60% by weight of lyocell and 40% by weight of hemp were mixed, the separator had a tensile strength of 18.6 N / 15 mm, a tear strength of 124 gf · 16 sheets, and the mechanical strength was sufficiently satisfied, but the ESR was 0. .953Ω and low ESR, airtightness is 134 sec / 100 ml, and high shielding property. The electric double layer capacitor has an internal resistance of 166 mΩ and a leakage current of 416 μA compared with the third embodiment. Can be further suppressed.

  On the other hand, Comparative Example 1 in which the raw material composition of the separator was mixed with 5% by weight of lyocell and 95% by weight of hemp has excellent mechanical strength with a tensile strength of 21.6 N / 15 mm and a tear strength of 201 gf · 16 sheets. However, since the blending amount of lyocell is small, the air density is as low as 86 sec / 100 ml, and the blending amount of natural fiber that causes ESR deterioration is large, so the ESR is as high as 1.136Ω. As a result, the internal resistance of the electric double layer capacitor was increased to 217 mΩ and the leakage current was 469 μA, and the short-circuit defect rate was 5%.

  From the above, it was found that the raw material composition of the separator is preferably 10% by weight or more as shown in Example 3, for example, and more preferably 60% by weight or more as shown in Example 4.

  In Example 5, polynosic rayon fiber was used as the regenerated cellulose fiber that can be beaten, and the paper was made with the same paper machine as in Example 1. However, the physical properties of the separator and the performance of the electric double layer capacitor used the lyocell fiber of Example 1. It was the same level as the thing.

In Examples 6 to 11 and Comparative Examples 2 to 6, the separator characteristics and the electric double layer capacitor characteristics depending on the beating degree and density of the separators were compared.
As shown in the measurement results in Table 1, in Examples 6 to 11 in which paper was made with 50 to 0 ml of CSF of the fiber layer A and 600 to 10 ml of CSF of the fiber layer B, the density of the fiber layer A was 0.26 to 0. .68 g / cm ³ , the density of the fiber layer B is 0.17 to 0.45 g / cm ³ , the total density is 0.22 to 0.57 g / cm ³ , the tensile strength is 10 N / 15 mm or more, and the tear strength is 20 gf. -Having 16 sheets or more, when producing an electric double layer capacitor, there was no inconvenience such as breakage of the separator during element winding.

  Moreover, the ESR is 0.784 to 0.988 Ω and low ESR, and the airtightness is 101 to 287 sec / 100 ml, indicating a high shielding property. The internal resistance of the electric double layer capacitor is 56 to 189 mΩ, and the leakage current is 273 to 448 μA. It is kept low.

On the other hand, in Comparative Example 2 and Comparative Example 3 in which paper making was performed with 100 ml of CSF of the fiber layer A, since the beating was suppressed and the amount of fibrils was reduced, the density of the fiber layer A was as low as 0.21 g / cm ^3. Since the strength was as weak as 6.9 N / 15 mm, the separator was broken by winding the element, and an electric double layer capacitor for evaluation could not be produced.

Further, in Comparative Example 4 in which the fiber layer A was paper-made with 0 ml of CSF and a density of 0.80 g / cm ³ , the strength of the separator was not a problem, but the ESR was 1.154Ω due to being too dense with a gas density of 356 Sec / 100 ml. Thus, the internal resistance of the electric double layer capacitor was as high as 237 mΩ. From this result, it was found that the beating degree of the fiber layer A is preferably 50 to 0 ml of CSF, and the density is preferably 0.25 to 0.70 g / cm ³ .

Further, in Comparative Example 5 in which paper was made with CSF 650 ml of fiber layer B, the density of fiber layer B was 0.12 g / cm ³ , and in Comparative Example 6 in which paper was made with CSF 0 ml, the density of fiber layer B was 0.53 g / cm ^3. However, due to excessive and insufficient beating, the tear strength was reduced to 14 gf · 16 sheets in Comparative Example 5 and 18 gf · 16 sheets in Comparative Example 6, so that when winding the electric double layer capacitor, the element winding As a result, the separator was broken, and the defect rate was 5%. From this result, it was found that the beating degree of the fiber layer B is preferably 600 to 10 ml of CSF, and the density is preferably 0.15 to 0.50 g / cm ³ .

Further, as the total density of the two layers, as shown in Comparative Example 3, when the total density is 0.17 g / cm ³ , the beating of both the fiber layer A and the fiber layer B can be suppressed, so that the tensile strength and the tear strength can be reduced. Therefore, the separator was broken by winding the element, and an electric double layer capacitor for evaluation could not be produced. Further, as shown in Comparative Example 4, when the total density is 0.63 g / cm ³ , the ESR becomes high, so that the internal resistance of the electric double layer capacitor is deteriorated. From this result, it was found that the total density of the two layers is preferably 0.20 to 0.60 g / cm ³ .

In Examples 12 to 17 and Comparative Examples 7 to 9, the separator characteristics depending on the separator thickness and the electric double layer capacitor characteristics were compared.
As shown in the measurement results of Table 1, in Example 12 where paper was made with a fiber layer A thickness of 5 μm, a fiber layer B thickness of 5 μm, and a total thickness of 10 μm, the separator had a tensile strength of 10 N / 15 mm or more and a tear strength. When the electric double layer capacitor was manufactured, there was no problem such as breakage of the separator due to element winding. In the electric double layer capacitor, the internal resistance is 45 mΩ and the leakage current is 439 μA.

  In Example 13, a separator made of paper with a thickness of 145 μm of fiber layer A, a thickness of 5 μm of fiber layer B, and a total thickness of 150 μm, in Example 14, a thickness of 5 μm of fiber layer A and a thickness of 145 μm of fiber layer B, total A separator made of paper with a thickness of 150 μm was obtained, but the internal resistance of the electric double layer capacitor was as low as 197 mΩ in Example 13, 186 mΩ in Example 14, 264 μA in Example 13, and 286 μA in Example 14. It has been.

  In Example 15 where paper was made with a fiber layer A thickness of 10 μm, a fiber layer B thickness of 10 μm, and a total thickness of 20 μm, compared to Example 12, the internal resistance was equivalent to 42 mΩ, and the leakage current was 421 μA. The leakage current can be further suppressed without deteriorating the internal resistance.

  Example 16 was made with a fiber layer A thickness of 10 μm, a fiber layer B thickness of 50 μm and a total thickness of 60 μm, and a fiber layer A thickness of 50 μm, a fiber layer B thickness of 10 μm and a total thickness of 60 μm. In Example 17, compared with Examples 13 and 14, the internal resistance of the electric double layer capacitor was 60 mΩ in Example 16, 167 mΩ in Example 17, and the leakage current was 305 μA in Example 16, Example 17 Thus, the internal resistance can be reduced while sufficiently suppressing the leakage current.

  On the other hand, in Comparative Example 7 in which the paper was made with a fiber layer A thickness of 3 μm, a fiber layer B thickness of 3 μm, and a total thickness of 6 μm, the separator had a tensile strength of 5.9 N / 15 mm and a tear strength. As a result, the separator was broken by winding the element, and an electric double layer capacitor for evaluation could not be produced.

  Further, Comparative Example 8 in which the paper was made with a fiber layer A thickness of 155 μm, a fiber layer B thickness of 5 μm, and a total thickness of 160 μm, a fiber layer A thickness of 5 μm, a fiber layer B thickness of 155 μm, and a total thickness of 160 μm. In Comparative Example 9, which was paper-made in comparison with Examples 13 and 14, due to the increased thickness of the separator, the air density was 326 sec / 100 ml in Comparative Example 8 and 307 Sec / 100 ml in Comparative Example 9. By being too dense, the ESR is 1.121Ω in Comparative Example 8 and 1.086Ω in Comparative Example 9, and the internal resistance of the electric double layer capacitor is deteriorated to 224mΩ in Comparative Example 8 and 207mΩ in Comparative Example 9. did.

  From the above results, it is found that the thickness of the fiber layer A of the separator is preferably 5 to 145 μm as shown in Examples 12 to 14, and preferably 10 to 50 μm as shown in Examples 15 to 17. did.

Similarly, the thickness of the fiber layer B was found to be preferably 5 to 145 μm as shown in Examples 12 to 14, and 10 to 50 μm as shown in Examples 15 to 17.
Further, the total of the two layers was found to be preferably 10 to 150 μm as shown in Examples 12 to 14, more preferably 20 to 60 μm as shown in Examples 15 to 17.

  In Conventional Example 1, 100% by weight of lyocell was beaten to 0 ml of CSF, and paper was made with a long net paper machine. However, since the tear strength was as low as 9 gf · 16 sheets, the element was wound up when producing an electric double layer capacitor. The separator broke and the element defect rate was 10%. The performance of the electric double layer capacitor was good with a low internal resistance and a small leakage current value.

  In the separator of Conventional Example 2, 80% by weight of lyocell is mixed with 20% by weight of PET, and a layer of paper made with a long paper machine using raw materials beaten to 0 ml of CSF and a film layer made of polyethylene as a raw material and manufactured by a film manufacturing apparatus. Although it is a laminated two-layer structure, since the film layer is too dense, the airtightness of the separator is as high as 674 sec / 100 ml, and the internal resistance of the electric double layer capacitor is deteriorated to 432 mΩ.

As described above, according to the present embodiment, the fiber layer A containing 10% by weight or more of regenerated cellulose fibers that can be beaten and made with a long or short mesh, has a CSF of 50 to 0 ml and a density of 0.25 to 0.70 g. / cm ³ , a layer having a thickness of 5 to 145 μm, and a fiber layer B made of paper by a circular mesh having a CSF of 600 to 10 ml, a density of 0.15 to 0.50 g / cm ³ , and a layer having a thickness of 5 to 145 μm With the structure, the separator as a whole has a density of 0.2 to 0.6 g / cm ³ and a thickness of 10 to 150 μm, so that the separator has a mechanical strength that does not break during winding and laminating, and high An electric double layer capacitor separator that achieves shielding and low ESR can be provided.

  Further, by using the separator, it is possible to provide an electric double layer capacitor capable of improving productivity without adversely affecting internal resistance and leakage current characteristics.

  The above description describes an example in which the separator of the present embodiment is used for an electric double layer capacitor, and the description of the details of the other configuration and manufacturing method of the electric double layer capacitor is omitted. In the type electric double layer capacitor, the electrode material and the electrolyte material are not particularly limited, and various types can be used.

  Furthermore, the separator can be applied not only to an electric double layer capacitor but also to a lithium ion capacitor. Even if it is a lithium ion capacitor, performance can be secured as a separator used in a lithium ion battery.

Claims (10)

A capacitor separator interposed between a pair of polarizable electrodes and capable of holding an electrolyte solution containing an electrolyte,
It has a two-layer structure consisting of a fiber layer A that is made of a long or short mesh paper and a fiber layer B that is made of a circular mesh paper,
The fiber layer A and the fiber layer B contain 10% by weight or more of regenerated cellulose fibers that can be beaten, the density of the entire two-layer structure is 0.2 to 0.6 g / cm ³ , and the thickness is 10 to 150 μm. There is a capacitor separator. A capacitor separator interposed between a pair of polarizable electrodes and capable of holding an electrolyte solution containing an electrolyte,
It has a two-layer structure consisting of a fiber layer A made with a long or short mesh and a fiber layer B made with a circular mesh,
The fiber layer A and the fiber layer B contain 10% by weight or more of regenerated cellulose fibers that can be beaten, the density of the entire two-layer structure is 0.2 to 0.6 g / cm ³ , and the thickness is 20 to 60 μm. There is a capacitor separator. 3. The capacitor separator according to claim 1, wherein the fiber layer A and the fiber layer B contain 60% by weight or more of regenerated cellulose fibers that can be beaten. The capacitor separator according to any one of claims 1 to 3, wherein the regenerated cellulose fiber that can be beaten is selected from solvent-spun rayon fiber or viscose regenerated cellulose fiber. The fiber layer A contains regenerated cellulose fibers beaten to CSF 50 to 0 ml, has a density of 0.25 to 0.70 g / cm ³ , and a thickness of 5 to 145 μm. The separator for capacitors according to any one of the above. The fiber layer A contains regenerated cellulose fibers beaten to CSF 50 to 0 ml, has a density of 0.25 to 0.70 g / cm ³ , and a thickness of 10 to 50 μm. The separator for capacitors according to any one of the above. The fiber layer B contains regenerated cellulose fibers beaten to CSF 600 to 10 ml, has a density of 0.15 to 0.50 g / cm ³ , and a thickness of 5 to 145 μm. The separator for capacitors according to any one of the above. The fiber layer B contains regenerated cellulose fibers beaten to CSF 600 to 10 ml, has a density of 0.15 to 0.50 g / cm ³ , and a thickness of 10 to 50 μm. The separator for capacitors according to any one of the above. A capacitor using the capacitor separator according to claim 1. 10. The capacitor according to claim 9, wherein the capacitor is an electric double layer capacitor or a lithium ion capacitor.