KR102389257B1 - Electric double layer capacitor and method of producing the same - Google Patents

Abstract

The electric double layer capacitor according to the embodiment includes a first electrode, a second electrode spaced apart from the first electrode, and a separator disposed between the first electrode and the second electrode, wherein the first electrode includes: A first current collector including a first pattern part and a first electrode mixture layer disposed on the first current collector, wherein the second electrode includes a second current collector including a second pattern part and on the second current collector and a second electrode mixture layer disposed on the , wherein the first pattern portion and the second pattern portion are disposed at positions corresponding to each other.

Description

Electric double layer capacitor and manufacturing method thereof

The present invention relates to an electric double layer capacitor and a method for manufacturing the same, and more particularly, to an electric double layer capacitor having improved capacitance and energy output characteristics by improving the specific surface area of an electrode, and a method for manufacturing the same.

As interest in depletion of fossil fuels such as coal, oil and natural gas and environmental pollution increases, interest in high-performance energy storage technology using electrochemical devices is rising.

The electrochemical device includes a lithium ion secondary battery (LIB) and a super capacitor, and the super capacitor is mainly used in a high-output field where the lithium ion secondary battery is difficult to be applied.

The super capacitor may be classified into a pseudo capacitor, a hybrid capacitor, and an electric double layer capacitor (EDLC).

The pseudo capacitor is a capacitor that stores energy by Faradaic oxidation and reduction reactions at the electrode and electrolyte interface, and the hybrid capacitor is a capacitor using an asymmetric electrode having different positive and negative electrodes to realize high output and high capacity characteristics. am.

The electric double layer capacitor (EDLC) is a supercapacitor that uses a charge/discharge phenomenon by movement of ions and a surface chemical reaction, unlike a battery using a chemical reaction. That is, the electric double layer capacitor has the characteristics of an electrolytic capacitor and a secondary battery, so it can be rapidly charged and discharged, and has high efficiency, so it can be used semi-permanently, and occupies more than 80% of the total super capacitor market.

The total output energy (E) of the electric double layer capacitor is proportional to the capacitance (C), and the capacitance (C) is proportional to the surface area (A) of the active material. Accordingly, the electric double layer capacitor uses, as an electrode active material, a carbon material having a large surface area per unit mass, that is, a specific surface area, such as activated carbon.

In particular, the electrode of the electric double layer capacitor is formed by disposing an electrode mixture layer including the active material on an electrode current collector.

Conventionally, in order to improve the specific surface area of the electrode mixture layer, the surface of the electrode mixture layer is pressed with a press having irregularities, etc. to form the irregularities on the surface of the electrode mixture layer.

However, as described above, when the electrode mixture layer is pressed with a press having irregularities, at least one of the electrode current collector and the electrode mixture layer is broken or torn, so that the specific surface area is reduced or it cannot be used as an electrode.

In addition, in the prior art, an alignment process of forming a concave-convex pattern on the positive electrode and the negative electrode, respectively, and disposing a separator between the positive electrode and the negative electrode by the above-described method is performed. In this case, there is a problem in that a portion of the electrode mixture layer formed on the positive electrode and the negative electrode is damaged by the press, so that it is difficult to accurately align the positive electrode and the negative electrode.

In addition, there is a problem in that the separator is bent by the patterns formed on each of the anode and the cathode. In detail, each of the anode and the cathode may include protrusions formed in the press and concave portions formed between the protrusions. In this case, the anode protrusion is disposed at a position corresponding to the cathode protrusion and the cathode concave part, respectively, and the separator is disposed between the anode and the cathode. However, as described above, when the alignment is not properly performed, the anode protrusion may be disposed to face the cathode concave part, and accordingly, the separator may be bent and disposed so that a short circuit is formed between the anode and the cathode. There are problems that arise.

In addition, there is a problem in that there is a limit in improving the specific surface area of the electrode mixture layer because the height, width, thickness, spacing, etc. of the unevenness that can be formed in the press is limited.

Therefore, a new electric double layer capacitor capable of solving the above problems is required.

An embodiment is to provide an electric double layer capacitor capable of minimizing damage to an electrode and a method of manufacturing the same.

In addition, the embodiment intends to provide an electric double layer capacitor in which a finer pattern is formed on an electrode current collector and a method for manufacturing the same.

In addition, the embodiment intends to provide an electric double layer capacitor capable of preventing a short circuit between the anode and the cathode from being easily aligned between the anode and the cathode, and a method for manufacturing the same.

In addition, the embodiment is to provide an electric double layer capacitor capable of maintaining the reliability of the separator and a method of manufacturing the same when winding a laminate in which a positive electrode, a separator, and a negative electrode are stacked.

That is, the embodiment aims to provide an electric double layer capacitor capable of minimizing damage to an electrode and improving a specific surface area, and thus having improved capacitance and energy output characteristics, and a method of manufacturing the same.

The electric double layer capacitor according to the embodiment includes a first electrode, a second electrode spaced apart from the first electrode, and a separator disposed between the first electrode and the second electrode, wherein the first electrode includes: A first current collector including a first pattern part and a first electrode mixture layer disposed on the first current collector, wherein the second electrode includes a second current collector including a second pattern part and on the second current collector and a second electrode mixture layer disposed on the , wherein the first pattern portion and the second pattern portion are disposed at positions corresponding to each other.

In the electric double layer capacitor according to the embodiment, the pattern portion is formed on the electrode current collector, so that damage to the electrode mixture layer disposed on the electrode current collector can be minimized.

In addition, in the electric double layer capacitor according to the embodiment, since the pattern portion on the electrode current collector is formed by an etching process, the width and depth of the pattern portion can be finely adjusted, and a uniform pattern can be formed on the electrode current collector. there is. Accordingly, the specific surface area of the electrode mixture layer can be improved.

In addition, since the pattern portions formed on the anode and the cathode are disposed at positions corresponding to each other, it is possible to easily align the anode and the cathode, and the separator disposed between the anode and the cathode is not bent. It can be arranged flat to prevent a short circuit between the positive electrode and the negative electrode.

In addition, since the separator is supported by the protrusions formed on the anode and the cathode, respectively, when the laminate including the separator is wound, the separator may maintain reliability.

That is, since the electric double layer capacitor according to the embodiment does not physically process the electrode, damage to the electrode can be minimized, and the specific surface area of the electrode current collector can be improved, thereby improving the capacitance, and between the positive electrode and the negative electrode. electrical stability can be improved.

1 is an exploded perspective view schematically illustrating an electric double layer capacitor according to a first embodiment.
2 is a diagram schematically illustrating a first electrode, a second electrode, and a separator according to the first embodiment.
3 is a diagram schematically illustrating an enlarged shape of the active material according to the first embodiment.
4 is a view showing a crystal structure of a crystalline region (region A in FIG. 3) according to the first embodiment.
5 is a cross-sectional view illustrating a first current collector according to the first embodiment.
6 is a plan view illustrating a first current collector according to the first embodiment.
7 is an enlarged view of a first electrode, a second electrode, and a separator in the electric double layer capacitor according to the first embodiment.
8 is a diagram illustrating a first current collector according to a second embodiment.
9 is a view illustrating a first current collector according to a third embodiment.
10 is a diagram illustrating a first current collector according to a fourth embodiment.
11 is a flowchart illustrating a method of manufacturing an electric double layer capacitor according to embodiments.
12 is a diagram illustrating a process in which an active material is formed by heat treatment and activation treatment in a method of manufacturing an electric double layer capacitor according to embodiments.

In the description of embodiments, each layer (film), region, pattern or structure is “on” or “under” the substrate, each layer (film), region, pad or patterns. The description of being formed in " includes all those formed directly or through another layer. The standards for the upper/above or lower/lower layers of each layer will be described with reference to the drawings.

In addition, when it is said that a certain part is "connected" with another part, it includes not only the case where it is "directly connected" but also the case where it is "indirectly connected" with another member interposed therebetween. In addition, when a part "includes" a certain component, this means that other components may be further provided without excluding other components unless otherwise stated.

Hereinafter, an electric double layer capacitor according to a first embodiment will be described with reference to the drawings.

1 is an exploded perspective view schematically showing an electric double layer capacitor 1000 according to a first embodiment, and FIG. 2 is a first electrode 100, a second electrode 200 and a separator of the electric double layer capacitor 1000. (300) is a diagram showing.

1 and 2 , the electric double layer capacitor 1000 may include a first electrode 100 , a second electrode 200 , a separator 300 , and a cover case 500 .

The cover case 500 may accommodate the first electrode 100 , the second electrode 200 , and the separator 300 .

The cover case 500 may include a rigid material. In detail, the cover case 500 may include metal, glass, quartz, or the like. For example, the cover case 500 may include aluminum, and may be transparent or translucent including glass or quartz. Alternatively, the cover case 500 may include a flexible material. For example, the cover case 500 may include plastic. In addition, the cover case 500 may have a cylindrical shape. Accordingly, the cover case 500 may protect the first electrode 100 , the second electrode 200 , and the separator 300 accommodated therein from external impact. However, the embodiment is not limited thereto, and the cover case 500 may include various materials and may have various shapes.

The first electrode 100 may be disposed in the cover case 500 . The first electrode 100 may include a first current collector 110 and a first electrode mixture layer 120 .

The first electrode 100 may be an anode. In this case, the first current collector 110 may be a positive electrode current collector, and the first electrode mixture layer 120 may be a positive electrode mixture layer.

The first current collector 110 may include a conductive metal. For example, the first current collector 110 may include aluminum (Al), copper (Cu), gold (Au), silver (Ag), stainless steel (STS), tantalum (Ta), titanium (Ti), It may include at least one of niobium (Nb) and an alloy formed of a combination thereof. Alternatively, the first current collector 110 may include a conductive resin. For example, the first current collector 110 may include a carbon-based conductive polymer.

The first current collector 110 may be in the form of a foil. However, the embodiment is not limited thereto, and the first current collector 110 may have various shapes, such as a mesh shape.

The first electrode mixture layer 120 may be disposed on the first current collector 110 . In detail, the first electrode mixture layer 120 may be disposed on at least one surface of the first current collector 110 . For example, the first electrode mixture layer 120 may be respectively disposed on one surface of the first current collector 110 and the other surface of the first current collector 110 opposite to the one surface.

The first electrode mixture layer 120 may include an active material 1 including carbon. For example, the active material 1 of the first electrode mixture layer 120 may be activated carbon. In detail, the active material 1 of the first electrode mixture layer 120 may be porous activated carbon.

The second electrode 200 may be disposed in the cover case 500 . The second electrode 200 may include a second current collector 210 and the second electrode mixture layer 220 .

The second electrode 200 may be a cathode. In this case, the second current collector 210 may be a negative electrode current collector, and the second electrode mixture layer 220 may be a negative electrode mixture layer.

The second current collector 210 may include a conductive metal. For example, the second current collector 210 may include aluminum (Al), copper (Cu), gold (Au), silver (Ag), stainless steel (STS), tantalum (Ta), titanium (Ti), It may include at least one of niobium (Nb) and an alloy formed of a combination thereof. Alternatively, the second current collector 210 may include a conductive resin. For example, the second current collector 210 may include a carbon-based conductive polymer.

In addition, the second current collector 210 may be in the form of a foil. However, the embodiment is not limited thereto, and the second current collector 210 may have various shapes, such as a mesh shape.

The second electrode mixture layer 220 may be disposed on the second current collector 210 . In detail, the second electrode mixture layer 220 may be disposed on at least one surface of the second current collector 210 . For example, the second electrode mixture layer 220 is opposite to one surface of the second current collector 210 facing one surface of the first current collector 110 and one surface of the second current collector 210 . and may be respectively disposed on the other surface of the second current collector 210 . The second electrode mixture layer 220 may include the active material 1 including carbon. For example, the active material 1 of the second electrode mixture layer 220 may be activated carbon. In detail, the active material 1 of the second electrode mixture layer 220 may be porous activated carbon.

At least one of the first electrode 100 and the second electrode 200 may be formed by coating a composition for forming an electrode including the active material 10 on the current collector.

Alternatively, at least one of the first electrode 100 and the second electrode 200 may be formed by rolling the electrode-forming composition including the active material 1 on the current collector by rolling. there is.

Alternatively, at least one of the first electrode 100 and the second electrode 200 is formed by manufacturing the composition for forming an electrode including the active material 1 in the form of a sheet and attaching it to the current collector. After drying, it may be formed.

However, the embodiment is not limited thereto, and the first electrode 100 and/or the second electrode 200 may be formed by a method capable of satisfying required characteristics.

The composition for forming an electrode may include a binder and a conductive material in addition to the active material 1 .

The binder may impart adhesion to the composition for forming an electrode. For example, the binder is carboxymethyl cellulose (CMC), polyvinylpyrrolidone (PVP), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), polyethylene (PE), polypropylene (PP) and polyvinyl alcohol (PVA). However, the embodiment is not limited thereto, and may include a material capable of satisfying properties required for the binder.

The binder may be included in an amount of about 1 wt% to about 45 wt% based on 100 wt% of the total composition for forming an electrode. When the amount of the binder is less than about 1% by weight based on 100% by weight of the total composition for forming an electrode, physical adhesion is reduced and thus the binder cannot properly function. In addition, when the binder exceeds about 45% by weight based on 100% by weight of the total composition for forming an electrode, the content of the conductive material may be reduced and conductivity may be reduced.

The conductive material may impart conductivity to the composition for forming an electrode. For example, the conductive material may include at least one of carbon black, graphene, carbon nanotubes (CNT), and carbon nanofibers (CNF). However, the embodiment is not limited thereto, and may include a material capable of satisfying properties required for the conductive material.

The conductive material may be included in an amount of about 1% to about 45% by weight based on 100% by weight of the total composition for forming an electrode. When the amount of the conductive material is less than about 1% by weight based on 100% by weight of the total composition for forming an electrode, the conductivity of the composition for forming an electrode may decrease. In addition, when the amount of the conductive material exceeds about 45% by weight based on 100% by weight of the total composition for forming an electrode, the content of the binder may be reduced and adhesion may be deteriorated.

In addition, the composition for forming an electrode may further include a solvent. The solvent may be water or an organic solvent. In addition, the solvent may be included in an amount of about 10% to about 97% by weight based on 100% by weight of the total composition for forming an electrode. When the solvent is out of the above range, adhesion and conductivity may be reduced.

The separator 300 may be disposed between the first electrode 100 and the second electrode 200 . The separator 300 may be disposed in contact with the first electrode 100 and the second electrode 200 . For example, one surface of the separator 300 and the other surface opposite to the one surface are one surface of the first electrode 100 and the second electrode 200 facing the one surface and the other surface of the separator 300, respectively. ) and can be placed in direct contact with one surface. The first electrode 100 and the second electrode 200 may be disposed to be spaced apart by the separator 300 . Accordingly, it is possible to prevent a short circuit from occurring between the first electrode 100 and the second electrode 200 .

The separator 300 includes polyethylene nonwoven fabric, polypropylene nonwoven fabric, polyester nonwoven fabric, polyacrylonitrile porous separator, poly(vinylidene fluoride) hexafluoropropane copolymer porous separator, cellulose porous separator, kraft paper, and rayon fiber. It may include at least one. However, the embodiment is not limited thereto, and the separator 300 may include a material capable of satisfying characteristics required for a separator of a super capacitor.

The first electrode 100 , the separator 300 , and the second electrode 200 may be sequentially stacked and wound. For example, the first electrode 100 , the separator 300 , and the second electrode 200 are sequentially stacked to form a roll, and then an adhesive member disposed around the roll. It can be maintained in the form of a roll through That is, the first electrode 100 , the separator 300 , and the second electrode may be accommodated in the cover case 500 in the form of a roll.

In this case, the separator 300 may be flatly disposed by the first electrode 100 and the second electrode 200 . In detail, the separator 300 may maintain flatness without being bent by the pattern portions formed on each of the first electrode 100 and the second electrode 200 .

Here, the flatness of the separator 300 means that the first electrode 100, the separator 300, and the second electrode 200 are sequentially stacked to form a laminate, and the laminate is rolled ) may mean the appearance of the separation membrane 300 before winding in the shape.

In addition, the first electrode 100 , the second electrode and the separator 300 may be impregnated with an electrolyte.

The electrolyte may be an aqueous electrolyte or a non-aqueous electrolyte. Preferably, the electrolyte may be a non-aqueous electrolyte in consideration of high voltage characteristics and energy density. The electrolyte may include a solvent and an electrolyte salt.

The solvent may be an organic electrolyte. For example, the solvent is acetonitrile (ACN), propylene carbonate (PC), sulfolane (SL), adiponitrile (AND), ethylene carbonate (EC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC) ), dimethylsulfone (DMS), ethylmethanesulfonate (EMS), gamma-butyrolactone (GBL), formamide (DMF), dimethyl ketone (DMK), and the like may be at least one.

In addition, the electrolyte salt is tetraethylammonium tetrafluoroborate (TEABF ₄ ), trimethylethylammonium tetrafluoroborate (TEMABF ₄ ), bipyrrizinium tetrafluoroborate (SPBBF ₄ ), hexafluorophosphate (EMIPF ₆ ) ) and 1-butylpyridinium bisimide (BPTFSI) and the like.

The electrolyte salt may dissociate in the solvent. For example, the electrolyte salt may be ionized by dissociation in the solvent. In detail, the electrolyte may be an electrolyte containing a cation and an anion by dissociating an electrolyte salt in a solvent. That is, the electrolyte may be used as the electrolyte of the electric double layer capacitor 1000 by ionizing the electrolyte salt in the solvent.

The electric double layer capacitor 1000 according to the first embodiment may further include a separator. For example, when the electric double layer capacitor 1000 includes a plurality of separators, an external separator 400 may be disposed. In detail, the electric double layer capacitor 1000 may further include an external separator 400 in addition to the separator 300 disposed between the first electrode 100 and the second electrode 200 .

The external separator 400 may be disposed on the first electrode 100 . In detail, the external separator 400 may be disposed between the cover case 500 and the first electrode 100 . The external separator 400 may be disposed in contact with the first electrode 100 . For example, one surface of the external separator 400 may be disposed in direct contact with the other surface of the first electrode 100 . In addition, the other surface of the external separator 400 may be disposed in direct contact with the other surface of the second electrode 200 . That is, when the electric double layer capacitor 1000 further includes the external separator 400 , the external separator 400 , the first electrode 100 , and the separator 300 are located in the cover case 500 . and a laminate in which the second electrode 200 is sequentially stacked may be wound and accommodated.

That is, even when an electrode mixture layer is formed on both one surface and the other surface of each of the first current collector 110 and the second current collector 210 by the external separator 400 , the first electrode 100 during winding ) and the second electrode 200 may prevent a short circuit from occurring. In addition, it is possible to prevent a short circuit from occurring between the cover case 500 and the first electrode 100 by the external separator 400 .

The electric double layer capacitor 1000 may further include a lead wire. For example, the electric double layer capacitor 1000 may include a first lead wire 600 and a second lead wire 700 .

The first lead wire 600 may be connected to the first electrode 100 . For example, the first lead wire 600 may be connected to and in direct contact with the first electrode 100 . Also, the second lead wire 700 may be connected to the second electrode 200 . For example, the second lead wire 700 may directly contact and be connected to the second electrode 200 .

The first lead wire 600 and the second lead wire 700 may be formed to extend from the inside of the cover case 500 to the outside of the cover case 500 .

3 is a diagram schematically illustrating an enlarged shape of the active material according to the first embodiment.

4 is a diagram illustrating a crystal structure of a crystalline region (region A in FIG. 3 ) in the active material according to the first embodiment.

3 and 4 , the active material 1 included in the first electrode 100 and the second electrode 200 of the electric double layer capacitor 1000 will be described in more detail.

Referring to FIG. 3 , the active material 1 may be formed of a carbon material including carbon. For example, the active material 1 may be formed using a carbon material such as petroleum-based pitch, coal-based pitch, raw coke (green coke), calcination coke, and coke dust. . The active material 1 formed of the carbon material may be one of activated carbon, graphite, fullerene (C60), soft carbons, carbon black, and the like. However, the embodiment is not limited thereto, and may include a material capable of satisfying properties required for the active material 1 .

The active material 1 may include an amorphous material 10 and a crystalline material 20 . The amorphous 10 may have an irregular atomic arrangement, and the crystalline 20 may have a crystal lattice.

The crystalline 20 and the amorphous 10 may be mixed in the active material 1 . For example, the crystalline material 20 may be irregularly formed and disposed in the active material 1 . In the active material 1 , the crystalline 20 may be surrounded by the amorphous 10 .

The crystalline 20 may be formed in the process of heat-treating the carbon material. In detail, the crystalline 20 may be formed by partially crystallizing the amorphous 10 of the carbon material by the heat treatment process.

The crystalline material 20 may serve as a passage for the electrolyte ions 30 to easily flow. That is, the active material 1 may have a lower electrical resistance and improved electrical conductivity due to the crystalline 20 .

The amorphous 10 may serve to store the electrolyte ions 30 . In detail, the active material 1 may include an amorphous material 10 including a plurality of pores 11 . The amorphous 10 may have a specific surface area increased by the pores 11 . That is, the active material 1 is a material including a plurality of pores 11 , and the electrolyte ions 30 may pass through the crystalline material 20 and be adsorbed to the amorphous material 10 . Accordingly, the active material 1 may have improved capacitance due to the amorphous 10 .

The active material 1 may have pores 11 having a size of about 1 nm or less. The size of the pores 11 may be an average diameter length. When the active material 1 includes a plurality of pores 11 , the size of the pores 11 may be the same. In detail, the pores 11 may have the same diameter. Alternatively, the sizes of the pores 11 may be different from each other. In detail, the pores 11 may have different diameters. Alternatively, the active material 1 may include both pores 11 having the same diameter and pores 11 having different diameters. The specific surface area of the active material 1 may be increased by the pores 11 , that is, the pores 11 included in the amorphous 10 .

The presence or absence of the pores 11 in the active material 1 may be a factor affecting the specific surface area of the active material 1 . In addition, the size of the pores 11 may also be a factor affecting the specific surface area. That is, the size of the pores 11 and the distribution characteristics of the pores 11 may be factors affecting the amount and/or mobility of the electrolyte ions 30 disposed in the pores 11 .

In addition, the pores 11 may be about 60% to about 85% of the total volume of the amorphous (10). When the volume of the pores 11 is less than about 60% of the total volume of the amorphous 10 , the specific surface area may be reduced, and thus the capacitance may be reduced. In addition, when the volume of the pores 11 exceeds about 85% of the total volume of the amorphous 10 , the specific surface area is increased to decrease the accessibility of the electrolyte ions 30 , and thus the electrical mobility is decreased As a result, the overall electrical characteristics may be deteriorated.

The specific surface area of the active material 1 may be about 200 m ² /g to about 1200 m ² /g. When the specific surface area of the active material 1 is within the above range, the electrolyte ions 30 can easily flow between the lattices of the crystalline 20 or into the pores 11 of the amorphous 10 to improve the electrostatic capacity. can

In this case, the pores 11 may be formed by an activation process. In detail, the pores 11 may be formed by alkali activation treatment of the heat-treated carbon material. The size and ratio of the pores 11 formed in the active material 1 by the alkali activation treatment can be adjusted.

Referring to FIG. 4 , the active material 1 according to the first embodiment may include carbon. In this case, the active material 1 may include the crystalline 20 having a layered structure. In detail, the crystalline 20 may have a layered structure in which carbon atoms are bonded by a covalent bond and a van der Waals bond. In more detail, in the crystalline form 20, a carbon atom is covalently bonded to three carbon atoms disposed at adjacent positions on the same plane, and the carbon atoms are opposite to carbon atoms disposed adjacent to each other on a different plane, that is, in a different layer. It may have a layered structure joined by a Der Waals bond. A bond length (l) between the carbon atoms bonded by the covalent bond may be about 1.42 Å.

The carbon atoms bonded by the covalent bond may extend in a first direction. For example, the first direction may be an a-axis direction of the crystalline material 20 . In detail, the a-axis direction may be a direction in which the (100) plane of the crystalline material 20 grows. In addition, the carbon atoms bonded by a van der Waals bond may extend in the second direction. For example, the second direction may be a c-axis direction of the crystalline material 20 . In detail, the c-axis direction may be a direction in which the (002) plane of the crystalline material 20 grows.

The first direction and the second direction may be different directions. In detail, the first direction and the second direction may intersect. In more detail, the first direction and the second direction may be perpendicular to each other.

The crystalline 20 may have a layered structure as described above. In this case, the spacing between the layers in the layered structure, that is, the lattice spacing d ₀ of the crystalline 20 may be about 0.37 nm to about 0.42 nm. Preferably, the lattice spacing d ₀ of the crystalline 20 may be about 0.37 nm to about 0.40 nm. That is, the distance between the (002) planes of the crystalline material 20 may be about 0.37 nm to about 0.40 nm.

When the lattice spacing d ₀ of the crystalline 20 is less than about 0.37 nm, it may not be easy to insert and move the electrolyte ions 30 between the layers of the crystalline 20 . In addition, when the lattice spacing (d ₀ ) of the crystalline material 20 exceeds about 0.42 nm, the distance between the layers of the crystalline material 20 may increase and thus the crystallinity may be lost. That is, the van der Waals bond between carbon atoms may be broken and crystallinity may be lost. Accordingly, there is a problem in that electrical conductivity or capacitance is lowered.

An electrode according to the first embodiment will be described in more detail with reference to FIGS. 5 to 7 .

FIG. 5 is a cross-sectional view illustrating a cross-section of the first current collector 110 according to the first embodiment, and FIG. 6 is a plan view illustrating a plane of the first current collector 110 .

5 and 6 , the first electrode 100 may include a first current collector 110 and a first electrode mixture layer 120 disposed on the first current collector 110 .

The first current collector 110 may include a conductive metal. For example, the first current collector 110 may include aluminum (Al), copper (Cu), gold (Au), silver (Ag), stainless steel (STS), tantalum (Ta), titanium (Ti), It may include at least one of niobium (Nb) and an alloy formed of a combination thereof. Preferably, the first current collector 110 may include aluminum (Al).

The thickness of the first current collector 110 may be about 25 μm to about 45 μm. In detail, the thickness of the first current collector 110 may be about 27 μm to about 43 μm. Preferably, the thickness of the first current collector 110 may be about 30 μm to about 40 μm. When the thickness of the first current collector 110 is less than about 25 μm, the current collector may be damaged in the process of patterning the first current collector 110 or coating the first electrode mixture layer 120 , so that the electrostatic capacitance This may be reduced and furthermore, it may not be able to perform the role of the current collector. In addition, when the thickness of the first current collector 110 exceeds about 45 μm, the total volume of the electric double layer capacitor 1000 may be increased, and the amount of the electrode mixture layer that can be disposed in the limited space of the cover case is As a result, there is a problem in that the overall capacitance is reduced. Accordingly, the first current collector 110 may have a thickness of about 25 μm to about 45 μm as described above, and preferably, when the thickness is about 30 μm to about 40 μm, the first current collector 110 may have a thickness of about 30 μm to about 40 μm. It is possible to improve the amount of the electrode mixture layer disposed on the overall capacitance can be improved.

The first current collector 110 may include a first pattern portion formed on at least one surface. For example, the first current collector 110 may include a first pattern portion formed on one surface facing the separation film 300 and the other surface opposite to the one surface. In addition, when the first pattern portion is formed on the one surface and the other surface, the first pattern portions respectively formed on the one surface and the other surface may be formed at positions corresponding to each other.

The first pattern portion may be formed by an etching process. For example, the first pattern part may be formed by dry etching or wet etching the first current collector 110 .

The first pattern portion may include a plurality of first protrusions 111 and a first concave portion 116 formed between the first protrusions 111 adjacent to each other. That is, a plurality of first protrusions 111 and a plurality of first concave portions 116 may be formed on the first current collector 110 .

The first protrusion 111 formed on one surface of the first current collector 110 has a shape protruding toward the separator 300, and the first protrusion 111 may include an upper surface and a side surface. there is. The upper surface may be formed to be parallel to the long axis of the first current collector 110 . In addition, the side surface may be inclined in a vertical direction from the end of the upper surface, and the lower end of the side surface may be connected to the first concave portion 116 .

The first protrusions 111 may be disposed to be spaced apart from each other at regular intervals. For example, when the electrodes 100 and 200 and the separator 300 are wound in a roll shape to form a cell, the gap d1 between the first protrusions 111 is a winding start region. It can be constant from to the winding end area. In detail, the interval d1 between the adjacent first protrusions 111 may be about 1 μm to about 15 μm. In more detail, the distance d1 may be about 3 μm to about 13 μm. Preferably, the distance d1 may be about 5 μm to about 10 μm. Accordingly, the first electrode mixture layer 120 may be uniformly formed and wound on the first current collector 110 .

Also, when the interval d1 between the adjacent first protrusions 111 is less than about 1 μm, the effect of improving the specific surface area of the first electrode mixture layer 120 by the pattern portion may be insignificant. Also, when the distance d1 between the first protrusions 111 exceeds about 15 μm, the first electrode mixture layer 120 may not be formed on the first protrusions 111 . In detail, when the distance d1 exceeds about 15 μm, the composition for forming an electrode may be intensively disposed on the first concave portion 116 due to the low viscosity of the composition for forming an electrode. Accordingly, the specific surface area of the first electrode mixture layer 120 may be reduced. That is, when the interval d1 is about 5 μm to about 10 μm, the composition for forming an electrode can be uniformly distributed on the first protrusion 111 and the first concave portion 116 , so that the first The specific surface area of the electrode mixture layer 120 may be improved.

In addition, when a cell is formed by winding a stack in which the first electrode 100 , the separator 300 and the second electrode 200 are stacked in a roll shape, the first protrusion 111 ) The spacing between them may be constant. In detail, the interval d1 may be constant from the winding start area to the winding end area. Accordingly, the first electrode mixture layer 120 may be uniformly formed and wound on the first current collector 110 .

In addition, the height h1 of the first protrusion 111 may be about 1 μm to about 15 μm. In more detail, the height h1 may be about 3 μm to about 13 μm. Preferably, the height h1 may be about 5 μm to about 10 μm. When the height h1 of the first protrusion 111 is less than about 1 μm, the effect of improving the specific surface area of the first electrode mixture layer 120 by the pattern portion may be insignificant. Also, when the height h1 of the first protrusion 111 exceeds about 15 μm, the first electrode mixture layer 120 may not be formed on the first protrusion 111 . In detail, since the composition for forming an electrode for forming the first electrode mixture layer 120 has a low viscosity, the composition for forming the electrode may be intensively disposed in the first concave portion 116 . Accordingly, the specific surface area of the first electrode mixture layer 120 may be reduced. That is, when the height h1 is about 5 μm to about 10 μm, the composition for forming an electrode can be uniformly distributed on the first protrusion 111 and the first concave portion 116 , so that the first The specific surface area of the electrode mixture layer 120 may be improved.

The first current collector 110 may have a waffle structure as shown in FIG. 6 . In detail, the first current collector 110 may be formed in a waffle structure including a plurality of first protrusions 111 and first concave portions 116 that are spaced apart from each other at a predetermined interval d1 . Accordingly, the specific surface area of the first electrode mixture layer 120 disposed on the first current collector 110 may be increased.

However, the embodiment is not limited thereto, and the first current collector 110 may be formed in a stripe structure. For example, the first protrusions 111 and the first concave portions 116 may be formed in a stripe structure extending in one direction.

7 is an enlarged view of the first electrode 100 , the second electrode 200 , and the separator 300 according to the first embodiment.

Referring to FIG. 7 , the second electrode 200 may include a second current collector 210 and a second electrode mixture layer 220 disposed on the second current collector 210 .

The second current collector 210 may include a conductive metal. For example, the second current collector 210 may include aluminum (Al), copper (Cu), gold (Au), silver (Ag), stainless steel (STS), tantalum (Ta), titanium (Ti), It may include at least one of niobium (Nb) and an alloy formed of a combination thereof. Preferably, the second current collector 210 may include aluminum. That is, the second current collector 210 may include a material corresponding to the first current collector 110 .

The thickness of the second current collector 210 may be about 25 μm to about 45 μm. In detail, the thickness of the second current collector 210 may be about 27 μm to about 43 μm. Preferably, the thickness of the second current collector 210 may be about 30 μm to about 40 μm. That is, the second current collector 210 may be formed to have a thickness corresponding to that of the first current collector 110 . Preferably, when the thickness of the second current collector 210 is about 30 μm to about 40 μm, the amount of the electrode mixture layer disposed on the second current collector 210 can be improved to increase the overall capacitance. can be improved

In addition, the second current collector 210 may include a second pattern portion formed on at least one surface. For example, the second current collector 210 may include a plurality of second pattern portions formed on one surface facing the separation film 300 and the other surface opposite to the one surface. In addition, when the second pattern portion is formed on the one surface and the other surface, the second pattern portions respectively formed on the one surface and the other surface may be formed at positions corresponding to each other.

The second pattern part may be formed by an etching process. For example, the second pattern part may be formed by dry etching or wet etching the second current collector 210 .

The second pattern part may include a plurality of second protrusions 211 and a second concave part 216 formed between the second protrusions 211 adjacent to each other. That is, a plurality of second protrusions 211 and a plurality of second protrusions 211 may be formed on the second current collector 210 .

The second protrusion 211 formed on one surface of the second current collector 210 may have a shape protruding toward the separation film 300 , and the second protrusion 211 may include an upper surface and a side surface. there is. The upper surface may be formed to be parallel to the long axis of the second current collector 210 . In addition, the side surface may be inclined in a vertical direction from an end of the upper surface, and a lower end of the side surface may be connected to the second concave portion 216 .

The second protrusions 211 may be disposed to be spaced apart from each other at regular intervals. For example, when the electrodes 100 and 200 and the separator 300 are wound in a roll shape to form a cell, the gap d2 between the second protrusions 211 is a winding start region. It can be constant from to the winding end area. In detail, the interval d2 between the adjacent second protrusions 211 may be about 1 μm to about 15 μm. In more detail, the distance d2 may be about 3 μm to about 13 μm. Preferably, the distance d2 may be about 5 μm to about 10 μm. Accordingly, the second electrode mixture layer 220 may be uniformly formed and wound on the second current collector 210 .

Also, when the interval d2 between the adjacent second protrusions 211 is less than about 1 μm, the effect of improving the specific surface area of the second electrode mixture layer 220 by the pattern portion may be insignificant. Also, when the distance d2 between the second protrusions 211 exceeds about 15 μm, the second electrode mixture layer 220 may not be formed on the second protrusions 211 . In detail, when the distance d2 exceeds about 15 μm, the composition for forming an electrode may be intensively disposed on the second concave portion 216 due to the low viscosity of the composition for forming an electrode. Accordingly, the specific surface area of the second electrode mixture layer 220 may be reduced. That is, when the interval d2 is about 5 μm to about 10 μm, the composition for forming an electrode can be uniformly distributed on the second protrusion 211 and the second concave portion 216 , so that the first The specific surface area of the electrode mixture layer 120 may be improved.

In addition, the height h2 of the second protrusion 211 may be about 1 μm to about 15 μm. In more detail, the height h2 may be about 3 μm to about 13 μm. Preferably, the height h2 may be about 5 μm to about 10 μm. When the height h2 of the second protrusion 211 is less than about 1 μm, the effect of improving the specific surface area of the second electrode mixture layer 220 by the pattern portion may be insignificant. Also, when the height h2 of the second protrusion 211 exceeds about 15 μm, the second electrode mixture layer 220 may not be formed on the second protrusion 211 . In detail, since the composition for forming an electrode for forming the second electrode mixture layer 220 has a low viscosity, the composition for forming the electrode may be intensively disposed in the second concave portion 216 . Accordingly, the specific surface area of the second electrode mixture layer 220 may be reduced. That is, when the height h2 is about 5 μm to about 10 μm, the composition for forming an electrode can be uniformly distributed on the second protrusion 211 and the second concave portion 216 , so that the first The specific surface area of the electrode mixture layer 120 may be improved.

The shape of the first pattern part may correspond to the shape of the second pattern part. For example, the heights of the first protrusion 111 and the second protrusion 211 may correspond to each other, and intervals between the protrusions formed in each pattern part may correspond to each other. Also, the first pattern part may be disposed at a position corresponding to the second pattern part. In detail, the first protrusion 111 may be disposed at a position corresponding to the second protrusion 211 , and the first concave part 116 may be disposed at a position corresponding to the second concave part 216 . can be In more detail, the first protrusion 111 and the second protrusion 211 may be disposed to face each other with the separation membrane 300 interposed therebetween, and the second concave portion 216 and the second concave portion 216 may be disposed to face each other with the separation membrane 300 interposed therebetween.

That is, when the first current collector 110 is formed in a waffle structure as shown in FIG. 6 , the second current collector 210 may be formed in a waffle structure. In detail, the second current collector 210 may be formed in a waffle structure including a plurality of second protrusions 211 and second concave portions 216 that are spaced apart from each other at a predetermined interval d2 . In addition, when the first protrusion 111 and the first concave part 112 are formed in a stripe shape extending in one direction, the second protrusion 211 and the second concave part 222 are also formed in a stripe shape. can be formed.

The first electrode mixture layer 120 may be formed on the first current collector 110 , and the second electrode mixture layer 220 may be formed on the second current collector 210 . The electrode mixture layers 120 and 220 may include the active material 1 described above.

Each of the first electrode mixture layer 120 and the second electrode mixture layer 220 may have a thickness of about 90 μm to about 110 μm. In detail, each of the electrode mixture layers 120 and 220 may have a thickness of about 95 μm to about 105 μm. Preferably, each of the electrode mixture layers 120 and 220 may have a thickness of about 98 μm to about 102 μm.

When the thickness of at least one electrode mixture layer of the first electrode mixture layer 120 and the second electrode mixture layer 220 is less than about 90 μm, the amount of the active material 1 included in the electrode mixture layer is The specific surface area may be reduced, and the overall capacitance may be reduced.

In addition, when the thickness of at least one electrode mixture layer of the first electrode mixture layer 120 and the second electrode mixture layer 220 exceeds about 110 μm, the specific surface area is improved by the above-described pattern portion. The effect is insignificant, and there is a problem in that the overall thickness of the electrode is increased. In addition, when the thickness of the electrode mixture layer exceeds about 110 μm, the first electrode 100, the separator 300, and the second electrode 200 are laminated and wound in a roll form, The electrode may be damaged by the thickness.

The first electrode mixture layer 120 may include a third pattern portion. In detail, the first electrode mixture layer 120 may include a third pattern portion formed on one surface. For example, the first electrode mixture layer 120 may include a third pattern portion formed on one surface facing the separator 300 .

The third pattern part may include a plurality of third protrusions 121 and a third concave part 126 formed between the third protrusions 121 adjacent to each other.

The third pattern part may be disposed on the first pattern part. For example, the third pattern part may be disposed at a position corresponding to the first pattern part. In detail, the third protrusion 121 may be disposed at a position corresponding to the first protrusion, and the third concave part 126 may be disposed at a position corresponding to the first concave part 116 . . The third pattern part may be formed by the first pattern part.

In addition, the third protrusion 121 may have a shape protruding toward the separation membrane 300 . In this case, it may be in direct contact with one surface of the separation membrane 300 , and the third concave portion 126 may be disposed to be spaced apart from the separation membrane 300 . That is, the third protrusions 121 may support the separation membrane 300 so as not to be bent while being disposed in the third concave portion 126 . For example, it is possible to prevent the separation membrane 300 from being bent in a 'U' or 'V' shape within the third concave part 126 by the third protrusion 121 . .

The second electrode mixture layer 220 may include a fourth pattern portion. In detail, the second electrode mixture layer 220 may include a fourth pattern portion formed on one surface. For example, the second electrode mixture layer 220 may include a fourth pattern portion formed on one surface facing the separator 300 .

The fourth pattern part may include a plurality of fourth protrusions 221 and a fourth concave part formed between the fourth protrusions 221 adjacent to each other.

The fourth pattern part may be disposed on the second pattern part. For example, the fourth pattern part may be disposed at a position corresponding to the second pattern part. In detail, the fourth protrusion 221 may be disposed at a position corresponding to the second protrusion 211 , and the fourth concave part 226 may be disposed at a position corresponding to the second concave part 216 . can be The fourth pattern part may be formed by the second pattern part.

In addition, the fourth protrusion 221 may have a shape protruding toward the separation film 300 . In this case, it may be in direct contact with the other surface of the separation membrane 300 , and the fourth concave portion 226 may be disposed to be spaced apart from the separation membrane 300 . That is, the fourth protrusions 221 may support the separation membrane 300 not to be bent into the fourth concave portion 226 . For example, it is possible to prevent the separation membrane 300 from being bent in a 'U' or 'V' shape within the fourth concave part 226 by the fourth protrusion 221 . .

In this case, the third pattern part and the fourth pattern part may be disposed at positions corresponding to each other. That is, the third pattern portion and the fourth pattern portion may be disposed to face each other with the separation film 300 as a boundary. In detail, the third protrusion 121 may be disposed at a position corresponding to the fourth protrusion 221 , and the third concave part 126 may be disposed at a position corresponding to the fourth concave part 226 . can be

That is, the separation film 300 may be disposed in a flat shape by the third pattern part and the fourth pattern part. In detail, the separation membrane 300 may be disposed in a flat shape by the third protrusion 121 and the fourth protrusion 221 .

For example, when the third protrusion 121 and the fourth concave part 226 are disposed at positions corresponding to each other, the third concave part 126 and the fourth protrusion 221 correspond to each other. may be placed in position. In this case, the separator 300 is disposed between the first electrode mixture layer 120 and the second electrode mixture layer 220 in a 'U' or 'V' shape, that is, in a bent shape to form a wave shape. can have In detail, when the separation membrane 300 is in direct contact with the third protrusion 121 , the separation membrane 300 may be in direct contact with the fourth concave portion 226 , and the separation membrane 300 may be in direct contact with the third protrusion 121 . When in direct contact with the concave portion 126 , the separator 300 may directly contact the fourth protrusion 221 . That is, a portion of the separator 300 is disposed in the concave portions of the first electrode mixture layer 120 and the second electrode mixture layer 220 to be bent in a 'U' or 'V' shape. can In this case, when the first electrode 100, the separator, and the second electrode 200 are laminated and wound, the separator 300 may be damaged, thereby reducing reliability and reducing the overall capacitance. there is.

That is, the electric double layer capacitor 1000 according to the embodiment may include the first electrode 100 and the second electrode 200 including the pattern part. In detail, the first electrode mixture layer 120 disposed on the first current collector 110 by forming a pattern portion on each of the first current collector 110 and the second current collector 210 by an etching process. and a pattern portion may be formed on the second electrode mixture layer 220 disposed on the second current collector 210 .

Accordingly, by forming a finer pattern on the current collector, the specific surface area of the electrode mixture layer disposed on the current collector can be maximized, thereby improving the overall capacitance of the electric double layer capacitor 1000 .

In addition, since the pattern forming process for improving the specific surface area on the electrode mixture layer can be omitted, process efficiency can be improved.

In addition, since the pattern portions respectively formed on the first electrode 100 and the second electrode 200 are disposed at positions corresponding to each other, process efficiency when the first electrode 100 and the second electrode 200 are aligned This can be improved.

In addition, the separator 300 disposed between the first electrode 100 and the second electrode 200 may be disposed flat. In detail, the separator 300 may maintain flatness by the third pattern portion of the first electrode mixture layer 120 and the fourth pattern portion of the second electrode mixture layer 220 . Accordingly, when the laminate in which the first electrode 100 , the separator 300 and the second electrode 200 are stacked is wound, the separator 300 is formed by the first electrode 100 and the second electrode 200 . It can be wound while maintaining reliability between the electrodes 200 .

Hereinafter, a modified example of the first current collector of the present invention will be described with reference to FIGS. 8 to 10 .

In the description of the modified example of the first current collector, the description of the same and similar components as those of the first embodiment described above will be omitted, and the same reference numerals will be given to the same and similar components.

8 is a diagram illustrating a first current collector according to a second embodiment.

Referring to FIG. 8 , the first current collector 110 may include a first pattern portion formed on at least one surface. For example, the first current collector 110 may include a first pattern portion formed on one surface facing the separation film 300 and the other surface opposite to the one surface. In addition, when the first pattern portion is formed on the one surface and the other surface, the first pattern portions respectively formed on the one surface and the other surface may be formed at positions corresponding to each other.

The first pattern portion may be formed by an etching process. For example, the first pattern part may be formed by dry etching or wet etching the first current collector 110 .

The first pattern portion may include a plurality of first protrusions 111 and a first concave portion 116 formed between the first protrusions 111 adjacent to each other. That is, a plurality of first protrusions 111 and a plurality of first concave portions 116 may be formed on the first current collector 110 .

The first protrusion 111 formed on one surface of the first current collector 110 has a shape protruding toward the separator 300, and the first protrusion 111 may include an upper surface and a side surface. there is. The upper surface may be formed to be parallel to the long axis of the first current collector 110 . A side surface of the first protrusion 111 may be inclined toward the first concave portion from an upper end of the first protrusion 111 , and a lower end of the side may be connected to the first concave portion 116 . .

A width of the first protrusion 111 may decrease toward an upper direction of the first current collector 110 . In detail, the width of the first protrusion 111 may decrease toward the separation film 300 . In addition, the width of the first concave portion 116 may increase toward the top of the first current collector 110 . In detail, the width of the first concave portion 116 may increase toward the separation film 300 . That is, the first pattern portion may be formed in a trapezoidal shape as shown in FIG. 8 .

The first protrusions 111 may be disposed to be spaced apart from each other at regular intervals. For example, when the electrodes 100 and 200 and the separator 300 are wound in a roll shape to form a cell, the gap d3 between the first protrusions 111 is a winding start region. It can be constant from to the winding end area. In detail, the distance d3 between the side ends of the first protrusions 111 disposed adjacent to each other may be about 1 μm to about 15 μm. In more detail, the distance d3 may be about 3 μm to about 13 μm. Preferably, the distance d3 may be about 5 μm to about 10 μm. When the spacing d3 is less than about 1 μm, the effect of improving the specific surface area of the first electrode mixture layer 120 by the pattern part may be insignificant, and when the spacing d3 exceeds about 15 μm , the ratio of the first concave portion 116 is increased, so that the composition for forming an electrode may be intensively disposed in the first concave portion 116 . Accordingly, the specific surface area of the first electrode mixture layer 120 may be reduced.

In addition, the height h3 of the first protrusion 111 may be about 1 μm to about 15 μm. In more detail, the height h3 may be about 3 μm to about 13 μm. Preferably, the height h3 may be about 5 μm to about 10 μm. When the height h3 of the first protrusion 111 is less than about 1 μm, the effect of improving the specific surface area of the first electrode mixture layer 120 by the first pattern portion may be insignificant. In addition, when the height h3 of the first protrusion 111 exceeds about 15 μm, the ratio of the first concave portion 116 increases so that the composition for forming an electrode is concentrated in the first concave portion 116 . can be placed as

That is, when the distance d3 is about 5 μm to about 10 μm and the height h3 is about 5 μm to about 10 μm, the first protrusion 111 and the first concave part 116 are It is possible to uniformly distribute the composition for forming an electrode on the surface, thereby improving the specific surface area of the first electrode mixture layer 120 .

Also, although not shown in the drawings, the second current collector 210 may be formed in a shape corresponding to the first current collector 110 . In detail, the second current collector 210 may include a second pattern portion corresponding to the first pattern portion and including a second protrusion portion 211 and a second concave portion 216 . In this case, the height of the second protrusion 211 may correspond to the height h3 of the first protrusion 111 , and the distance between the second protrusions 211 is between the first protrusions 111 . may correspond to the interval d3 of . That is, the second pattern portion may have a trapezoidal shape corresponding to the first pattern portion, and may be formed at a position corresponding to the first pattern portion.

Accordingly, a finer pattern can be formed on the first current collector 110 and the second current collector 210 to maximize the specific surface area of the electrode mixture layer disposed on the current collectors 110 and 120 . and it is possible to improve the capacitance of the electric double layer capacitor 1000 .

In addition, since the pattern portions respectively formed on the first electrode 100 and the second electrode 200 are disposed at positions corresponding to each other, process efficiency when the first electrode 100 and the second electrode 200 are aligned This can be improved.

In addition, the separator 300 may be flatly disposed by the pattern portions respectively formed on the first electrode 100 and the second electrode 200 . Accordingly, when the laminate in which the first electrode 100 , the separator 300 and the second electrode 200 are stacked is wound, the separator 300 is formed by the first electrode 100 and the second electrode 200 . It can be wound while maintaining reliability between the electrodes 200 .

9 is a view illustrating a first current collector according to a third embodiment.

Referring to FIG. 9 , the first current collector 110 may include a first pattern portion formed on at least one surface. For example, the first current collector 110 may include a first pattern portion formed on one surface facing the separation film 300 and the other surface opposite to the one surface. In addition, when the first pattern portions are formed on the one surface and the other surface, the first pattern portions respectively formed on the one surface and the other surface may be formed at positions corresponding to each other.

The first pattern portion may be formed by an etching process. For example, the first pattern part may be formed by dry etching or wet etching the first current collector 110 .

The first pattern portion may include a plurality of first protrusions 111 and a first concave portion 116 formed between the first protrusions 111 adjacent to each other. That is, a plurality of first protrusions 111 and a plurality of first concave portions 116 may be formed on the first current collector 110 .

The first protrusion 111 formed on one surface of the first current collector 110 has a shape protruding toward the separation film 300 and includes a side inclined with respect to the first concave portion 116 . can The lower end of the side surface may be connected to the first concave portion 116 .

A width of the first protrusion 111 may decrease toward an upper direction of the first current collector 110 . In detail, the width of the first protrusion 111 may decrease toward the separation film 300 . In addition, the width of the first concave portion 116 may increase toward the top of the first current collector 110 . In detail, the width of the first concave portion 116 may increase toward the separation film 300 . That is, as shown in FIG. 9 , the first protrusion 111 may have a triangular shape, and the first concave part 116 may have a trapezoidal shape.

The first protrusions 111 may be disposed to be spaced apart from each other at regular intervals. For example, when the electrodes 100 and 200 and the separator 300 are wound in a roll shape to form a cell, the gap d4 between the first protrusions 111 is a winding start region. It can be constant from to the winding end area. In detail, the distance d4 between the side ends of the first protrusions 111 disposed adjacent to each other may be about 1 μm to about 15 μm. In more detail, the distance d4 may be about 3 μm to about 13 μm. Preferably, the distance d4 may be about 5 μm to about 10 μm. When the spacing d3 is less than about 1 μm, the effect of improving the specific surface area of the first electrode mixture layer 120 by the pattern part may be insignificant, and when the spacing d4 exceeds about 15 μm , the ratio of the first concave portion 116 is increased, so that the composition for forming an electrode may be intensively disposed in the first concave portion 116 . Accordingly, the specific surface area of the first electrode mixture layer 120 may be reduced.

Also, the height h4 of the first protrusion 111 may be about 1 μm to about 15 μm. In more detail, the height h4 may be about 3 μm to about 13 μm. Preferably, the height h3 may be about 5 μm to about 10 μm. When the height h4 of the first protrusion 111 is less than about 1 μm, the effect of improving the specific surface area of the first electrode mixture layer 120 by the first pattern portion may be insignificant. In addition, when the height h4 of the first protrusion 111 exceeds about 15 μm, the ratio of the first concave portion 116 increases so that the composition for forming an electrode is concentrated in the first concave portion 116 . can be placed as

That is, when the distance d4 is about 5 μm to about 10 μm and the height h4 is about 5 μm to about 10 μm, the first protrusion 111 and the first concave part 116 are It is possible to uniformly distribute the composition for forming an electrode on the surface, thereby improving the specific surface area of the first electrode mixture layer 120 .

Also, although not shown in the drawings, the second current collector 210 may be formed in a shape corresponding to the first current collector 110 . In detail, the second current collector 210 may include a second pattern portion corresponding to the first pattern portion and including a second protrusion portion 221 and a second concave portion 216 . In this case, the height of the second protrusion 211 may correspond to the height h4 of the first protrusion 111 , and the distance between the second protrusions 211 is between the first protrusions 111 . may correspond to the interval d4 of . That is, the second protrusion 211 may be formed in a triangular pyramid shape corresponding to the first protrusion 111 , and the second concave part 216 may have a trapezoidal shape corresponding to the first concave part 116 . shape can be formed. In addition, the second pattern portion may be formed at a position corresponding to the first pattern portion.

Accordingly, a finer pattern can be formed on the first current collector 110 and the second current collector 210 to maximize the specific surface area of the electrode mixture layer disposed on the current collectors 110 and 120 . and it is possible to improve the capacitance of the electric double layer capacitor 1000 .

In addition, since the pattern portions respectively formed on the first electrode 100 and the second electrode 200 are disposed at positions corresponding to each other, process efficiency when the first electrode 100 and the second electrode 200 are aligned This can be improved.

In addition, the separator 300 may be flatly disposed by the pattern portions respectively formed on the first electrode 100 and the second electrode 200 . Accordingly, when the laminate in which the first electrode 100 , the separator 300 and the second electrode 200 are stacked is wound, the separator 300 is formed by the first electrode 100 and the second electrode 200 . It can be wound while maintaining reliability between the electrodes 200 .

10 is a diagram illustrating a first current collector according to a fourth embodiment.

Referring to FIG. 10 , the first current collector 110 may include a first pattern portion formed on at least one surface. For example, the first current collector 110 may include a first pattern portion formed on one surface facing the separation film 300 and the other surface opposite to the one surface. In addition, when the first pattern portion is formed on the one surface and the other surface, the first pattern portions respectively formed on the one surface and the other surface may be formed at positions corresponding to each other.

The first pattern portion may include a plurality of first protrusions 111 and a first concave portion 116 formed between the first protrusions 111 adjacent to each other. That is, a plurality of first protrusions 111 and a plurality of first concave portions 116 may be formed on the first current collector 110 .

The first protrusion 111 formed on one surface of the first current collector 110 has a shape protruding toward the separator 300, and the first protrusion 111 may include an upper surface and a side surface. there is. The upper surface may be formed to be parallel to the long axis of the first current collector 110 . In addition, the side surface may be inclined in a vertical direction from the end of the upper surface, and the lower end of the side surface may be connected to the first concave portion 116 .

The first protrusions 111 may be disposed to be spaced apart from each other. In detail, the interval d1 between the first protrusions 111 may be about 1 μm to about 15 μm. In more detail, the distance d1 may be about 3 μm to about 13 μm. Preferably, the distance d1 may be about 5 μm to about 10 μm.

In this case, the distance between the first protrusions 111 may be changed. For example, when a laminate in which the first electrode 100 , the separator 300 , and the second electrode 200 are stacked is wound in a roll shape, the space between the first protrusions 111 is The interval may gradually decrease from the winding start area to the winding end area. Also, although not shown in the drawings, the distance between the second protrusions 211 may also gradually decrease, and a changed distance value may correspond to the first protrusion 211 .

In detail, the radius of curvature of the laminate increases from the winding start area to the winding end area. That is, since the value of the radius of curvature in the winding start region is small, the side surfaces of the adjacent third protrusions 121 formed on the first electrode mixture layer 120 may contact each other, and the second electrode mixture layer ( Side surfaces of the adjacent fourth protrusions 221 formed on 220 may contact each other. Accordingly, the separator 300 disposed between the first electrode 100 and the second electrode 200 may be disposed in a bent shape in a 'U' or 'V' shape in the recess. .In this case, the separation membrane 300 may be bent and reliability may be lowered, and the separation membrane 300 may be damaged and thus may not perform its function.

However, in the embodiment, since the distance between the first protrusions 111 and the second protrusions 211 gradually decreases toward the winding end region, the reliability of the separator 300 can be maintained.

In addition, the specific surface area of the electrode mixture layer disposed on the current collectors 110 and 120 may be maximized by the first pattern portion and the second pattern portion, and thus the capacitance may be improved.

11 is a flowchart illustrating a method of manufacturing an electric double layer capacitor according to embodiments, and FIG. 12 is a view showing a process in which an active material is formed by heat treatment and activation treatment in a method of manufacturing an electric double layer capacitor according to the embodiments am.

11 and 12 , the method of manufacturing the electric double layer capacitor 1000 according to the embodiment may include a step of preparing a carbon material, a heat treatment step, an activation treatment step, an electrode forming step, and a cell forming step.

The step of preparing the carbon material may be a step of preparing the carbon material for forming the active material 1 . For example, the carbon material may be petroleum-based pitch, coal-based pitch, raw coke (green coke), calcination coke, and coke dust.

Subsequently, a step of heat-treating the carbon material to form the active material 1 may be performed. The heat treatment step may be a step of forming the crystalline 20 and the amorphous 10 in the active material (1).

The heat treatment step may be performed in an inert gas atmosphere. For example, the heat treatment step may be performed in helium, argon and nitrogen atmosphere. However, the embodiment is not limited thereto, and may be conducted in an atmosphere capable of satisfying the properties required during the heat treatment.

The heat treatment step may be performed at a temperature of about 650 °C to about 900 °C. When the heat treatment temperature is less than about 650° C., the crystalline 20 may not be formed in the active material 1 . In addition, when the heat treatment temperature exceeds about 900° C., the proportion of the crystalline material 20 formed in the active material 1 may be excessively large.

That is, the ratio of the crystalline 20 to the unit weight (g) of the active material 1 varies according to the heat treatment temperature, and the ratio of the crystalline 20 affects the specific surface area of the active material 1 It is possible to change the capacitance value.

In detail, as the heat treatment temperature decreases, the proportion of the crystalline 20 may decrease and the proportion of the amorphous 10 may increase. Accordingly, the specific surface area of the active material 1 may be increased, and thus the capacitance may be improved. In addition, as the heat treatment temperature increases, the proportion of the crystalline 20 may increase and the proportion of the amorphous 10 may decrease. Accordingly, the electrical conductivity of the active material 1 may be improved, but the capacitance may be decreased.

That is, in the heat treatment step according to the embodiment, the ratio of the crystalline 20 and the amorphous 10 in the active material 1 may be optimized by heat-treating the carbon material at a temperature of about 650 ° C. to about 900 ° C. Subsequently, the step of activating the active material 1 may be performed. The activation treatment step may be a step of adjusting the size and ratio of the pores 11 of the active material. In detail, in the activation treatment step, the amorphous 10 may be broken so that pores 11 may be formed in the amorphous 10 . In addition, in the activation treatment step, the lattice spacing of the crystalline material 20 may be adjusted. In detail, in the activation treatment step, the distance between the (002) planes of the crystalline material 20 may be adjusted. Accordingly, the specific surface area of the active material 1 may be increased.

The activation treatment step may be a step of activating the active material 1 using an activator including alkali. That is, the activation treatment step may be an alkali activation treatment step. The alkali may be lithium (Li), sodium (Na), potassium (K) metal, or the like. In this case, the active material 1 and the activator may be mixed in a weight ratio of about 1:0.8 to about 1:5.5. When the weight ratio of the active material 1 and the activator is less than about 1:0.8, the active material 1 cannot be sufficiently activated. Accordingly, even if the crystalline material 20 is present in the active material 1 , a lattice gap through which the electrolyte ions 30 can move may not be secured. In addition, when the weight ratio of the active material 1 and the activator exceeds about 1:5.5, the lattice spacing of the crystalline material 20 may become excessively large. That is, the distance between carbon atoms bonded by the van der Waals bond may increase, and thus the van der Waals bond may be broken. Accordingly, the crystallinity 20 may lose crystallinity. In addition, when the weight ratio of the active material 1 and the activator is out of about 1:0.8 to about 1:5.5, it has a size of about 1 nm or less, and about 60% to about 85 of the total volume of the amorphous 10 It may be difficult to implement the pores 11 occupying the %. That is, it may be difficult to adjust the size and/or ratio of the pores 11 . Accordingly, the overall electrical properties of the active material 1 may be deteriorated.

The activation treatment step may be performed in an inert gas atmosphere. The inert gas may be helium, argon, nitrogen, or the like. However, the embodiment is not limited thereto, and the activation treatment may be performed in an atmosphere capable of satisfying required characteristics.

The activation treatment step may be performed at a temperature of about 700 °C to about 1000 °C. When the activation treatment temperature is less than about 700 °C or greater than about 1000 °C, the lattice spacing of the crystalline 20 of the active material 1 may be less than about 0.37 nm or more than about 0.40 nm. Accordingly, a path through which the electrolyte ions 30 can move is not formed, so that the electrical conductivity and capacitance of the electric double layer capacitor 1000 may be reduced.

In addition, as the activation treatment step proceeds at a temperature of about 700° C. to about 1000° C., the pores 11 may have a size of about 1 nm or less, and the pores 11 have a total volume of the amorphous 10 . from about 60% to about 85% of However, when the activation treatment temperature is out of the above range, it may be difficult to control the size and/or ratio of the pores 11 . Accordingly, electrical characteristics of the electric double layer capacitor 1000 may be deteriorated.

Subsequently, a neutralization step, a cleaning step and a precursor step may be further performed.

The neutralization step may be performed after the activation treatment step. The neutralization step may be a step of neutralizing to remove the alkali-containing material used in the activation treatment step. In the neutralization step, hydrochloric acid, nitric acid, etc. may be used.

The washing step may be performed after the neutralization step. The cleaning step may be a step of cleaning the active material 1 . In the washing step, distilled water may be used.

After the washing step, the drying step may be performed. The active material 1 may be dried by the drying step.

Subsequently, the electrode forming step may be performed. The electrode forming step may be a step of forming the first electrode 100 and the second electrode 200 of the electric double layer capacitor 1000 described above.

In the electrode forming step, a pattern portion may be formed on the first electrode 100 and the second electrode 200 . In detail, pattern portions may be respectively formed on the first current collector 110 and the second current collector 210 by an etching process. The etching process may be dry etching or wet etching.

Accordingly, a first pattern portion including first protrusions 111 and first concave portions 116 may be formed on the first current collector 110 , and a plurality of pieces of the second current collector 210 may be formed on the second current collector 210 . A second pattern portion including second protrusions 211 and second concave portions 216 may be formed.

In the electrode forming step, the active material 1 may be mixed with a binder and a conductive material to form the first electrode mixture layer 120 or the second electrode mixture layer 220 . For example, the electrode mixture layer may be formed by coating on the current collector.

In this case, a third pattern portion disposed on the first pattern portion may be formed on the first electrode mixture layer 120 , and a second pattern portion disposed on the second pattern portion on the second electrode mixture layer 220 . 4 pattern portions may be formed. In detail, the first electrode mixture layer 120 is formed on a position corresponding to the third protrusion 121 formed on a position corresponding to the first protrusion 111 and the first concave part 116 . A third concave portion 126 may be included. In addition, the second electrode mixture layer 220 is formed on a position corresponding to the fourth protrusion 221 and the fourth concave part 226 formed on a position corresponding to the second protrusion 211 . A fourth concave portion 226 may be included. The third pattern part may be formed by the first pattern part, and the fourth pattern part may be formed by the second pattern part.

That is, the first electrode mixture layer 120 may be disposed on the first current collector 110 including a metal to serve as an anode or a cathode, and the second electrode mixture layer 220 may include a metal It may be disposed on the included second current collector 210 to serve as a negative electrode or a positive electrode.

In addition, the electrode mixture layers 120 and 220 may be adhered to each of the current collectors 110 and 210 by being pressurized at a certain pressure to increase the density of the electrode, and additional steps such as heating and drying are performed. Through this, it is possible to prevent the electrode mixture layer and the current collector from being peeled off.

A cell formation step may then proceed. The cell forming step may be a step of impregnating the first electrode 100 , the separator 300 , and the second electrode 200 in an electrolyte solution. That is, it may be a step of forming a supercapacitor cell by providing an electrolyte in which an electrolyte salt is dissociated between the first electrode 100 and the second electrode 200 .

In this case, the first electrode 100 , the separator 300 , and the second electrode 200 may be sequentially stacked and wound. In detail, after the first electrode 100 , the separator 300 , and the second electrode 200 are manufactured in a roll shape, the shape may be maintained through an adhesive member disposed around the roll. Accordingly, the first electrode 100 , the separator 300 , and the second electrode 200 may be accommodated in the cover case 500 in the form of a roll.

However, the embodiment is not limited thereto, and may be in the form of a stack in which the separator 300 is disposed between the first electrode 100 and the second electrode.

A lead wire may then be formed. The lead wire may include a first lead wire 600 and a second lead wire 700 . The first lead wire 600 may be connected to the first electrode 100 , and the second lead wire 700 may be connected to the second electrode 200 . In this case, the first lead wire 600 and the second lead wire 700 may be formed to extend from the inside of the cover case 500 to the outside.

Hereinafter, the operation and effect of the present invention will be described in more detail through Examples and Comparative Examples.

Example One

A carbon material was prepared by heat-treating the residual oil from the Naphta Cracking Center (NCC) process. The carbon material was heat-treated in an argon (Ar) atmosphere at a temperature of 750° C. for 6 hours at a hot spot of 60 Φ * 120 cm. Then, the carbon material was mixed with a KOH activator at a content ratio of 1:3, and activated at a temperature of 700° C. under an argon (Ar) atmosphere for 2 hours to prepare an active material.

Then, the positive electrode current collector and the negative electrode current collector including aluminum were etched to form a pattern including protrusions and concave portions, respectively, on the current collectors. In this case, the etching thickness was 5 μm and the etching width was 5 μm. That is, the etching was performed so that the height of the protrusions was 5 μm and the interval between the protrusions was 5 μm.

Then, an electrode material was prepared by mixing 95% by weight of the mixture of the active material and the conductive material and 5% by weight of the binder, and then, the electrode material was coated on the positive electrode current collector and the negative electrode current collector to form an electrode mixture layer, and a sheet After making the state, it was dried to prepare an electrode.

A separator is disposed between the prepared positive electrode and the negative electrode, the laminate in which the positive electrode, the separator and the negative electrode are stacked is wound and inserted into a circular cover case, and an electrolyte is injected to impregnate the positive electrode, the negative electrode, and the separator to make an electric double layer A capacitor was manufactured.

Then, the capacitance of the electric double layer capacitor was measured using a Hi-EDLC 16CH instrument (manufactured by Human Instrument).

Example 2

When the positive electrode current collector and the negative electrode current collector were etched, the etched thickness was 3 μm and the etched width was 3 μm. That is, the etching was performed so that the height of the protrusions was 3 μm and the interval between the protrusions was 3 μm.

Then, the capacitance of the electric double layer capacitor was measured using a Hi-EDLC 16CH instrument (manufactured by Human Instrument).

Example 3

When the positive electrode current collector and the negative electrode current collector were etched, the etching thickness was 1 μm and the etching width was 5 μm. That is, the etching was performed so that the height of the protrusions was 1 μm and the interval between the protrusions was 5 μm.

Then, the capacitance of the electric double layer capacitor was measured using a Hi-EDLC 16CH instrument (manufactured by Human Instrument).

Example 4

When the positive electrode current collector and the negative electrode current collector were etched, the etching thickness was 1 μm and the etching width was 3 μm. That is, the etching was performed so that the height of the protrusions was 1 μm and the interval between the protrusions was 3 μm.

Then, the capacitance of the electric double layer capacitor was measured using a Hi-EDLC 16CH instrument (manufactured by Human Instrument).

Example 5

When the positive electrode current collector and the negative electrode current collector were etched, the etched thickness was 5 μm and the etched width was 1 μm. That is, the etching was performed so that the height of the protrusions was 5 μm and the interval between the protrusions was 1 μm.

Then, the capacitance of the electric double layer capacitor was measured using a Hi-EDLC 16CH instrument (manufactured by Human Instrument).

Example 6

When the positive electrode current collector and the negative electrode current collector were etched, the etched thickness was 3 μm and the etched width was 1 μm. That is, the etching was performed so that the height of the protrusions was 3 μm and the interval between the protrusions was 1 μm.

Then, the capacitance of the electric double layer capacitor was measured using a Hi-EDLC 16CH instrument (manufactured by Human Instrument).

Example 7

When the positive electrode current collector and the negative electrode current collector were etched, the etched thickness was 1 μm and the etched width was 1 μm. That is, the etching was performed so that the height of the protrusions was 1 μm and the interval between the protrusions was 1 μm.

Then, the capacitance of the electric double layer capacitor was measured using a Hi-EDLC 16CH instrument (manufactured by Human Instrument).

comparative example

An electrode mixture layer was formed by coating an electrode material in which 95 wt% of a mixture of an active material and a conductive material and 5 wt% of a binder was mixed on the positive and negative current collectors without etching the positive and negative current collectors. . Then, it was made into a sheet state and dried, and the surface of the electrode mixture layer was patterned to prepare an electrode.

Then, the capacitance of the electric double layer capacitor was measured using a Hi-EDLC 16CH instrument (manufactured by Human Instrument).

Height of the protrusion formed on the current collector (㎛) Spacing between protrusions formed on the current collector (㎛) Capacitance (F/cc) Example 1 5 5 17.55 Example 2 3 3 16.48 Example 3 One 5 16.09 Example 4 One 3 15.75 Example 5 5 One 16.12 Example 6 3 One 15.91 Example 7 One One 14.4 Comparative Example 1 0 0 13.32

Referring to Table 1, it can be seen that the capacitance value of the transition double layer capacitor 1000 according to the embodiments is larger than the capacitance value of the electric double layer capacitor according to the comparative example. In addition, in the case of Example 1 in which the height of the protrusions is 5 μm and the interval between the protrusions is 5 μm, it can be seen that the capacitance is greatly improved compared to Comparative Example 1.

That is, in the electric double layer capacitor 1000 according to the embodiment, the first electrode mixture layer 120 and the second electrode mixture are formed by pattern portions respectively formed on the first current collector 110 and the second current collector 210 . Pattern portions each including protrusions and concave portions may be formed in the layer 220 as well. Accordingly, the specific surface area of the electrode mixture layer disposed on the current collectors 110 and 210 may be maximized, and thus the overall capacitance of the electric double layer capacitor may be improved.

In addition, when a pattern is formed on the electrode mixture layer to improve specific surface area, the electrode mixture layer may be damaged. A pattern portion is formed on the electrode mixture layers 120 and 220 to improve reliability of the electrode mixture layers 120 and 220 and improve process efficiency.

In addition, since the pattern portions respectively formed on the first electrode 100 and the second electrode 200 are disposed at positions corresponding to each other, the first electrode 100 and the second electrode 200 can be easily aligned. Also, the separator 300 disposed between the first electrode 100 and the second electrode 200 by the protrusions may maintain a flat surface. Accordingly, it is possible to prevent a short circuit between the first electrode 100 and the second electrode 200 from occurring, and the reliability of the separator 300 may be improved.

Features, structures, effects, etc. described in the above-described embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified for other embodiments by those of ordinary skill in the art to which the embodiments belong. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

In addition, although the embodiments have been described above, these are merely examples and do not limit the present invention, and those of ordinary skill in the art to which the present invention pertains are exemplified above in a range that does not depart from the essential characteristics of the present embodiment. It can be seen that various modifications and applications that have not been made are possible. For example, each component specifically shown in the embodiments may be implemented by modification. And differences related to these modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

Claims (10)

a first electrode;
a second electrode spaced apart from the first electrode; and
a separator disposed between the first electrode and the second electrode;
The first electrode is
a first current collector including a first pattern portion; and
A first electrode mixture layer disposed on the first current collector,
The second electrode is
a second current collector including a second pattern part; and
a second electrode mixture layer disposed on the second current collector;
The first pattern portion and the second pattern portion are disposed at positions corresponding to each other,
The first pattern portion includes a plurality of first protrusions and a first concave portion formed between the first protrusions adjacent to each other,
The second pattern portion includes a plurality of second protrusions and a second concave portion formed between the second protrusions adjacent to each other,
The first protrusion and the second protrusion are disposed at positions corresponding to each other,
The first concave portion and the second concave portion are disposed at positions corresponding to each other,
The first electrode mixture layer includes a third pattern portion disposed on the first pattern portion,
The second electrode mixture layer includes a fourth pattern portion disposed on the second pattern portion,
The third pattern portion and the fourth pattern portion are disposed at positions corresponding to each other. delete The method of claim 1,
In at least one of the first pattern part and the second pattern part, an interval between the protrusions adjacent to each other is 1 μm to 15 μm. The method of claim 1,
At least one of the first pattern part and the second pattern part has a height of the protrusion of 1 μm to 15 μm. The method of claim 1,
The total thickness of at least one of the first current collector and the second current collector is 25 μm to 45 μm. delete The method of claim 1,
The third pattern portion includes a third protrusion and a third concave portion formed between the third protrusions adjacent to each other,
The fourth pattern portion includes a fourth protrusion and a fourth concave portion formed between the fourth protrusions adjacent to each other,
The third protrusion is disposed at a position corresponding to the first protrusion,
The fourth protrusion is disposed at a position corresponding to the second protrusion. 8. The method of claim 7,
The separator may be disposed to be spaced apart from the third concave portion and the fourth concave portion. The method of claim 1,
Further comprising a cover case accommodating the first electrode, the separator, and the second electrode,
The first electrode, the separator, and the second electrode are wound in a roll shape and accommodated in the cover case. 10. The method of claim 9,
The distance between the patterns of at least one of the first pattern and the second pattern becomes narrower from the winding start area to the winding end area.

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