KR20200125082A - Energy storage device - Google Patents

Abstract

The present invention relates to an energy storage device. The energy storage device includes: a positive electrode including a positive electrode current collector made of a metal thin film and a positive electrode active material applied to both surfaces of the positive electrode current collector; a negative electrode including a negative electrode current collector made of the metal thin film and a negative electrode active material coated on both surfaces of the negative electrode current collector; and an electrode assembly comprising a separator disposed between the positive electrode and the negative electrode and electrically separating the positive electrode and the negative electrode, wherein at least one of the positive electrode current collector and the negative electrode current collector of the electrode assembly includes a plurality of holes having a size in a predetermined range and at least one of the positive active material and the negative active material is disposed to be inserted into the plurality of holes. The present invention provides the energy storage device with improved energy density and output properties.

Description

Energy storage device {ENERGY STORAGE DEVICE}

The present invention relates to an energy storage device, and more particularly, to an energy storage device with improved energy density and output characteristics.

Energy storage devices that store electrical energy include a battery and a capacitor. Among these capacitors, Ultra-Capacitor (UC) is also called Super Capacitor (SC) or Electric Double Layer Capacitor (EDLC), and is an energy storage device having intermediate characteristics between an electrolytic capacitor and a secondary battery. As a result, it is a next-generation energy storage device that can be used together and replaced with secondary batteries due to its high efficiency and semi-permanent life characteristics.

Ultracapacitors are often used as a replacement for storage batteries for applications that are not easy to maintain and require a long service life. Ultra capacitors have fast charging/discharging characteristics, and accordingly, not only auxiliary power sources such as mobile communication information devices such as mobile phones, notebook computers, and PDAs, but also electric vehicles that require high capacity, night road indicators, UPS (Uninterrupted Power Supply), etc. It is very suitable as the main power or auxiliary power of the product, and is widely used for such purposes.

As shown in Figure 1, the electrode assembly 1 of the ultracapacitor 5 according to the prior art is composed of an anode 10, a separator 30, and a cathode 20 to provide an electrochemical energy storage function. do. The electrode assembly 1 may be wound in a cylindrical or rectangular shape, and may be accommodated in the housing (or body case) of the ultracapacitor 5 together with an electrolyte.

A typical electrode assembly 1, as shown in (a) of FIG. 2, has an anode 10, a separator 30, and a cathode 20 sequentially stacked, and has a winding structure or a stack structure. . The positive electrode 10 is composed of a positive electrode current collector 11 made of a metal foil and a positive electrode active material 13 coated on both sides of the positive electrode current collector 11. The negative electrode 20 is composed of a negative electrode current collector 21 made of a metal thin film and a negative active material 23 coated on both surfaces of the negative electrode current collector 21. The separator 30 is disposed between the anode 10 and the cathode 20 to electrically separate the anode 10 and the cathode 20. The electrolyte provides electrolyte ions adsorbed or desorbed on the positive electrode active material 13 and the negative electrode active material 23 during charging/discharging of the ultracapacitor.

In order to realize the high-speed charging/discharging characteristics and high output characteristics of an ultracapacitor, it is necessary to smoothly provide the electrolyte ions of the electrolyte as the positive electrode active material and the negative electrode active material of the electrode assembly, so the flow of the electrolyte solution for smooth provision of the electrolyte ions is very important .

However, in the conventional electrode assembly 1, the flow of electrolyte is limited by the positive electrode current collector 11 and the negative electrode current collector 21, and the electrolyte ions existing between the positive electrode 10 and the negative electrode 20 10) Or, as the electrolyte ions present between the cathode 20 and the housing are consumed faster than the electrolyte ions, an imbalance of the electrolyte ions may occur. In order to solve this problem, as shown in FIG. 2 (b), an electrode assembly 2 having a plurality of holes formed by penetrating the anode 10 and the cathode 20 on the same vertical line. Proposed. The electrode assembly 2 can solve the supply imbalance of electrolyte ions to some extent by inducing the electrolyte to flow through a plurality of holes. However, the electrode assembly 2 has a problem in that energy density decreases due to electrode loss due to a plurality of holes. In addition, when the size of the hole is quite large, when the electrode assembly 2 is wound, the metal thin film of the positive electrode current collector 11 and the negative electrode current collector 21 may burst due to a plurality of holes.

It is an object of the present invention to solve the above and other problems. Another object is to provide an energy storage device with improved energy density and output characteristics.

Another object is to provide an energy storage device including a positive electrode and a negative electrode current collector in which a plurality of holes are formed in a predetermined pattern, and a positive electrode and negative electrode active material inserted into the holes of the positive and negative electrode current collectors.

Another object is to provide an energy storage device including a positive electrode current collector in which a plurality of holes are formed in a predetermined pattern and a positive electrode active material inserted into the holes of the positive electrode current collector.

Another object is to provide an energy storage device including a negative electrode current collector in which a plurality of holes are formed in a predetermined pattern and a negative active material inserted into the holes of the negative electrode current collector.

In order to achieve the above object, the present invention provides a positive electrode including a positive electrode current collector made of a metal thin film and a positive electrode active material coated on both surfaces of the positive electrode current collector; A negative electrode including a negative electrode current collector made of a metal thin film and a negative electrode active material coated on both surfaces of the negative electrode current collector; And a separator disposed between the positive electrode and the negative electrode and electrically separating the positive and negative electrodes, wherein at least one of the positive electrode current collector and the negative electrode current collector of the electrode assembly is in a certain range. It provides an energy storage device comprising a plurality of holes having a size, and at least one of the positive active material and the negative active material is inserted into the plurality of holes and disposed.

More preferably, the positive electrode and negative electrode current collectors are formed to have a roughening ratio in the range of 5% to 10%. In addition, the positive electrode and the negative electrode current collector is characterized in that it is formed to have a thickness of 20㎛ to 30㎛. In addition, the positive electrode and negative electrode current collectors are characterized in that they are formed to have a tension of 1.3 kg/cm or more.

More preferably, the plurality of holes is characterized in that formed to have a size of 10㎛ to 200㎛. In addition, the plurality of holes may be arranged at regular intervals on the surface of the current collector.

More preferably, when the plurality of holes includes first holes formed in the positive electrode current collector and second holes formed in the negative electrode current collector, the first holes and the second holes are formed to face each other based on the separator. It is characterized by being. In addition, the first holes are formed to be positioned between second holes formed in the anode current collector, and the second holes are formed to be positioned between first holes formed in the anode current collector.

More preferably, when the anode is disposed on the uppermost portion of the electrode assembly wound in a cylindrical shape, the plurality of holes are formed only in the anode assembly of the anode. In addition, when the cathode is disposed on the uppermost portion of the electrode assembly wound in a cylindrical shape, the plurality of holes are formed only in the cathode assembly of the cathode. In addition, the plurality of holes may be formed in a current collector region corresponding to an outermost region A of the electrode assembly wound in a cylindrical shape.

According to at least one of the embodiments of the present invention, by providing an electrode assembly including a positive electrode and a negative electrode current collector in which a plurality of holes are formed in a predetermined pattern, and a positive electrode and negative electrode active material inserted into the holes of the positive and negative electrode current collectors, There is an advantage in that the energy density and output characteristics of the energy storage device can be improved.

In addition, according to at least one of the embodiments of the present invention, by providing an electrode assembly including a positive electrode current collector in which a plurality of holes are formed in a predetermined pattern and a positive electrode active material inserted into the holes of the positive electrode current collector, the energy storage device There is an advantage in that energy density and output characteristics can be improved.

In addition, according to at least one of the embodiments of the present invention, by providing an electrode assembly including a negative electrode current collector in which a plurality of holes are formed in a predetermined pattern and a negative active material inserted into the holes of the negative electrode current collector, the energy storage device There is an advantage in that energy density and output characteristics can be improved.

However, the effects that can be achieved by the energy storage device according to the embodiments of the present invention are not limited to those mentioned above, and other effects not mentioned are common knowledge in the technical field to which the present invention belongs from the following description. It can be clearly understood by those who have.

1 is a view showing the configuration of an energy storage device according to the prior art;
2 is a view referred to for explaining a cross section of electrode assemblies according to the prior art;
3 is a perspective view showing the appearance of an energy storage device according to an embodiment of the present invention;
4 is a perspective view showing the appearance of an electrode assembly included in the energy storage device of FIG. 3;
5 is a plan view as viewed from above of an electrode assembly included in the energy storage device of FIG. 3;
6 is a view showing an unfolded electrode assembly included in the energy storage device of FIG. 3;
7 is a diagram illustrating a shape of a current collector included in the electrode assembly of FIG. 6;
8 is a cross-sectional view of an electrode assembly according to a first embodiment of the present invention;
9 is a cross-sectional view of an electrode assembly according to a second embodiment of the present invention;
10 is a cross-sectional view of an electrode assembly according to a third embodiment of the present invention;
11 is a cross-sectional view of an electrode assembly according to a fourth embodiment of the present invention.

Hereinafter, exemplary embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, but identical or similar elements are denoted by the same reference numerals regardless of reference numerals, and redundant descriptions thereof will be omitted. In the following description of the embodiments disclosed in the present specification, when it is determined that a detailed description of related known technologies may obscure the subject matter of the embodiments disclosed in the present specification, the detailed description thereof will be omitted. The accompanying drawings are only for making it easier to understand the embodiments disclosed in the present specification, and the technical idea disclosed in the present specification is not limited by the accompanying drawings, and all changes and equivalents included in the spirit and scope of the present invention It should be understood to include water or substitutes. In addition, in the accompanying drawings, the size of each component or a specific part constituting the component may be modified for convenience and clarity of description, and thus the actual size is not entirely reflected.

The present invention proposes an energy storage device with improved energy density and output characteristics. In addition, the present invention proposes an energy storage device including a positive electrode and a negative electrode current collector in which a plurality of holes are formed in a predetermined pattern, and a positive electrode and negative electrode active material inserted into the holes of the positive and negative electrode current collectors. In addition, the present invention proposes an energy storage device including a positive electrode current collector in which a plurality of holes are formed in a predetermined pattern and a positive electrode active material inserted into the holes of the positive electrode current collector. In addition, the present invention proposes an energy storage device including a negative electrode current collector in which a plurality of holes are formed in a predetermined pattern and a negative active material inserted into the holes of the negative electrode current collector.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the drawings.

3 is a perspective view showing the appearance of an energy storage device according to an embodiment of the present invention, FIG. 4 is a perspective view showing the appearance of an electrode assembly included in the energy storage device of FIG. 3, and FIG. 5 is a diagram illustrating the energy storage of FIG. It is a plan view as viewed from the top of the electrode assembly included in the device, FIG. 6 is a view showing an unfolded electrode assembly included in the energy storage device of FIG. 3, and FIG. 7 is a diagram illustrating the shape of a current collector included in the electrode assembly of FIG. 6 It is a drawing.

3 to 7, an energy storage device 100 according to an embodiment of the present invention includes an electrode assembly 110, a housing 120 accommodating the electrode assembly 110, and an interior of the housing 120. Electrolyte (not shown) accommodated in the electrode assembly 110 to impregnate the electrode assembly 110, the electrode terminal 130 protruding out of the housing 120, a plurality of electrically connecting the electrode assembly 110 and the electrode terminal 130 May include lead wires (not shown).

The electrode assembly 110 includes an anode 111, a separator 113 and a cathode 112. The electrode assembly 110 is formed by sequentially stacking an anode 111, a separator 113, and a cathode 112, and then winding it in a cylindrical shape.

The positive electrode 111 includes a positive electrode current collector made of a metal foil and a positive electrode active material made of porous activated carbon, and one or more positive lead wires are connected to one side thereof. It is preferable that the active material is removed from the current collector portion to which the positive lead wires are connected.

The negative electrode 112 includes a negative electrode current collector made of a metal thin film and a negative electrode active material made of porous activated carbon, and one or more negative lead wires are connected to one side thereof. Likewise, it is preferable that the active material is removed from the portion of the current collector to which the negative lead wires are connected.

At least one of the positive electrode current collector and the negative electrode current collector may include a plurality of holes having a size in a predetermined range. An active material may be inserted into a plurality of holes formed in the current collector. Through this electrode structure, the energy density and output characteristics of the energy storage device 100 may be improved.

For example, as shown in FIG. 7, the current collector 1110 constituting the positive electrode 111 and the negative electrode 112 may include a plurality of holes 1115 arranged in a matrix form. In this case, the plurality of holes 115 may be formed to have the same size (or width) with each other.

A separator 113 is disposed between the anode 111 and the cathode 112 to limit conduction of electric charges, and an electrolyte is filled in the housing 120. In this state, when a predetermined voltage is applied to the positive electrode 111 and the negative electrode 112, the positive and negative ions contained in the electrolyte move to the positive electrode 111 and the negative electrode 112, respectively, and penetrate into the detailed pores of the porous active material. .

The housing 120 is composed of an upper housing 122 and a lower housing 124. The lower housing 124 serves to accommodate the electrode assembly 110 and the electrolyte, and the upper housing 122 serves to seal (or cover) the open upper surface of the lower housing 124.

The upper housing 122 may be formed of at least one of a synthetic rubber material and a synthetic resin material. For example, the upper housing 122 may be formed of an EPDM (Ethylene Propylene Diene Monomer) layer and a bakelite layer.

The lower housing 124 may be formed of a metal material or a synthetic resin material. For example, the lower housing 124 may be made of aluminum (Al) or an aluminum alloy.

The upper housing 122 is coupled to an electrode terminal 130 including an anode terminal 132 to which one or more anode lead wires are connected and a cathode terminal 134 to which one or more cathode lead wires are connected. The electrode terminal 130 may be made of at least one of aluminum (Al), steel, or stainless steel to secure mechanical strength. Further, by coating the surface of the electrode terminal 130 with nickel (Ni) or tin (Tin), it is possible to secure bonding by soldering or the like.

The electrode terminal 130 allows the positive terminal 132 and the negative terminal 134 to be disposed in a direction perpendicular to each other outside of the upper housing 122. This is to allow the same bearing force to be generated no matter which direction the bending moment caused by the external force acts in any direction.

The plurality of lead wires are composed of one or more positive electrode lead wires and one or more negative electrode lead wires, and may be connected to the positive electrode current collector and the negative electrode current collector through a laser welding process or a rivet press-fitting process. The positive lead wires may be disposed on the positive electrode current collector at equal intervals, and the negative lead wires may be disposed on the negative electrode current collector at equal intervals.

The plurality of lead wires may be electrically connected to the electrode terminal 130 through a laser welding process or a rivet pressing process. That is, the positive lead wires may be electrically connected to the positive terminal 132 coupled to the upper housing 122, and the negative lead wires may be electrically connected to the negative terminal 134 coupled to the upper housing 122.

8 is a cross-sectional view of an electrode assembly according to a first embodiment of the present invention.

Referring to FIG. 8, the electrode assembly 500 according to the first embodiment of the present invention is formed by sequentially stacking an anode 510, a separator 530, and a cathode 520. The electrode assembly 500 is processed into a Jelly-Roll type winding structure or a stack structure and accommodated in the housing together with the electrolyte solution 550.

The separator 530 is disposed between the anode 510 and the cathode 520 and serves to electrically separate the anode 510 and the cathode 520. The separator 530 may be formed such that pulp-based or polymer-based unit fibers are arranged in a negative direction by a melt-blown process. The pulp refers to an aggregate of cellulose fibers obtained from wood or other fibrous plants by mechanical/chemical methods, and as the polymer-based synthetic resin, polyethylene, polypropylene, or the like may be used.

Meanwhile, in the present embodiment, the separator 530 is illustrated to be disposed between the anode 510 and the cathode 520, but is not limited thereto, and the anode 510 and the cathode 520 are not exposed to the outside. It will be apparent to those skilled in the art that the separator 530 may be additionally disposed outside the anode 510 and the cathode 520.

The positive electrode 510 includes a positive electrode current collector 511 made of a metal foil and a positive active material 513 made of porous activated carbon. The anode 510 faces the cathode 520 with the separator 530 interposed therebetween.

The positive electrode current collector 511 serves as a passage for electric charges discharged from the positive electrode active material 513 or supplied to the positive electrode active material 513. The positive electrode current collector 511 is formed of, for example, a metal thin film such as an aluminum foil or a copper foil.

The positive electrode active material 513 is activated carbon and is formed by a process of coating and drying an active material slurry on both surfaces of the positive electrode current collector 511. The positive electrode active material 513 serves to store electrical energy of the positive electrode.

The negative electrode 520 includes a negative electrode current collector 521 made of a metal thin film and a negative active material 523 made of porous activated carbon. Likewise, the cathode 520 faces the anode 510 with the separator 530 therebetween.

The negative electrode current collector 521 serves as a passage for electric charges discharged from the negative active material 523 or supplied to the negative active material 523. The negative electrode current collector 521 is formed of a metal thin film such as, for example, an aluminum foil or a copper foil.

The negative active material 523 is activated carbon and is formed by a process of coating and drying the active material slurry on both surfaces of the negative electrode current collector 31. The negative active material 523 serves to store electrical energy of the negative electrode.

The positive and negative current collectors 511 and 521 are manufactured through a thinning process of manufacturing an electrolytic metal foil by an electroplating method and a post-treatment process of performing a surface treatment on the metal foil. The positive and negative current collectors 511 and 521 surface-treat a metal thin film through a post-treatment process, thereby improving adhesion to the positive and negative active materials 513 and 523 and improving the reliability of the energy storage device 100. Through this surface treatment process, physical/electrical properties suitable for the energy storage device 100 may be imparted to the positive and negative current collectors 511 and 521.

The surfaces of the positive and negative current collectors 511 and 521 are roughened by an electric/chemical etching method or a sanding method. Here, roughening means increasing the adhesion between the positive and negative active materials 513 and 523 by artificially forming tooth protrusions or anchor patterns on the surfaces of the positive and negative current collectors 511 and 521 and increasing the surface area. do. In addition, the electro/chemical etching method is a process of increasing the effective area by etching the surface of the rolled metal thin film in an electrical or chemical method, and the sanding method physically collides fine particles on the surface of the metal thin film to increase the effective area. It is an increasing process.

The positive and negative current collectors 511 and 521 may be formed to have a roughening ratio in the range of about 5% to 10%. Here, the ratio of roughening of the positive and negative current collectors 511 and 521 refers to the ratio of the roughened region of the entire surface regions of the current collectors 511 and 521. When the surface of the positive and negative current collectors 511 and 521 is relatively roughened, the total area of the current collectors 511 and 521 decreases, so that the space for moving electric charges becomes smaller, the current collector ( The electrical resistance of the 511 and 521 increases. Conversely, when the surface of the positive and negative current collectors 511 and 521 is relatively less roughened, the positive and negative active materials 513 and 523 are coated on the surfaces of the positive and negative current collectors 511 and 521. Then, it can be easily peeled off, reducing the overall electric capacity.

Roughening ratio Resistance (mΩ) Capacity (F/cm ³ ) Example 1 5% 14.5 24.2 Example 2 7% 14.9 24.5 Example 3 10% 15.2 24.9 Comparative Example 1 3% 23 18 Comparative Example 2 15% 25 19 Comparative Example 3 20% 26 20

Table 1 is a table measuring changes in electrical resistance and capacity according to the roughening ratio of the current collector. As shown in Table 1, when the current collector has a roughening ratio of about 5% to 10%, it can be seen that the electrical resistance of the current collector is small while the total capacity is large.

The positive and negative current collectors 511 and 521 may be formed to have a thickness of about 20 μm to 30 μm. If the thickness of the positive electrode and negative electrode current collectors 511 and 521 is too large, there is a problem that the energy density of the electrode assembly 500 decreases, and if the thickness of the positive electrode and negative electrode current collectors 511 and 521 is too small, There is a problem in that productivity of the electrode assembly 500 is deteriorated due to the decrease in tensile strength and bending strength. The positive and negative current collectors 511 and 521 may be formed to have a tension of 1.3 kg/cm or more. In addition, the positive and negative current collectors 511 and 521 may be formed to have a purity of 99.4% to 99.9%.

The positive and negative current collectors 511 and 521 may include a plurality of holes (or openings) 540 having a size of about 10 μm to 200 μm. If the size of the holes 540 formed in the positive and negative current collectors 511 and 521 is too large, there is a problem that the productivity of the electrode assembly 500 decreases due to a decrease in tensile strength, and the size of the holes 540 is If it is too small, there is a problem that cations and anions of the electrolyte solution 550 cannot pass through the hole.

Hole(㎛) Resistance (mΩ) Capacity (F/cm ³ ) Example 1 10 14.4 24.1 Example 2 100 14.8 24.5 Example 3 200 15.2 25 Comparative Example 1 5 24 19 Comparative Example 2 250 26 19.5 Comparative Example 3 300 27 20

Table 2 is a table measuring changes in electrical resistance and capacity according to the hole size of the current collector. As shown in Table 2, when the hole size of the current collector is in the range of about 10 μm to 200 μm, it can be seen that the electrical resistance of the current collector is small while the total capacity is large.

The plurality of holes 540 formed in the positive and negative current collectors 511 and 521 are formed to have the same or similar size, and are formed to be disposed at regular intervals on the surfaces of the positive and negative current collectors 511 and 521. I can. In addition, the plurality of holes 540 may be formed to have a predetermined pattern on the surfaces of the positive and negative current collectors 511 and 521. For example, the plurality of holes 540 may be formed to have a lattice pattern or a matrix pattern.

The plurality of holes 540 may be formed so that the first holes 540 formed in the positive electrode current collector 511 and the second holes 540 formed in the negative electrode current collector 521 are positioned on the same vertical line. That is, the first holes 540 formed in the positive electrode current collector 511 and the second holes 540 formed in the negative electrode current collector 521 may be formed to face each other based on the separator 530.

The positive and negative active materials 513 and 523 may be formed by mixing a metal oxide and a binder, and an aqueous solvent may be used to widely coat both surfaces of the positive and negative current collectors 511 and 521.

The positive and negative active materials 513 and 523 may be uniformly applied and disposed on both surfaces of the positive and negative current collectors 511 and 521, as well as a plurality of positive and negative electrode current collectors 511 and 521. It may be inserted into the holes 540 and disposed. To this end, during the coating and drying process of the active material, the active materials 513 and 523 are coated on both surfaces of the positive and negative current collectors 511 and 521, and then predetermined in a direction perpendicular to the surfaces of the current collectors 511 and 521. The active material may be inserted into the plurality of holes 540 by applying a pressure of. As the amount of the active materials 513 and 523 present in the positive electrode 510 and the negative electrode 520 increases through the hole insertion process, the energy density of the electrode assembly 500 increases.

The positive and negative active materials 513 and 523 have a large surface area through microscopically almost circular pores, and the respective surfaces of the positive and negative active materials 513 and 523 come into contact with the electrolyte solution 550. In this state, when a predetermined voltage is applied to the positive and negative electrodes 510 and 520, positive and negative ions contained in the electrolyte 550 move to the positive and negative electrodes 510 and 520, respectively, and the positive and negative active materials 513, 523).

The electrolyte solution 550 provides electrolyte ions (ie, cation/anion) adsorbed or desorbed to the positive electrode and negative electrode active materials 513 and 523 of the electrode assembly 500 when charging/discharging the energy storage device 100. Play a role. As shown in the drawing, since the electrolyte 550 has a property of permeating the porous active material and the separator, it can be moved in the direction of the arrow through the plurality of holes 540 formed in the positive and negative current collectors 511 and 521. There will be. Accordingly, an imbalance between the concentration of electrolyte ions present between the positive electrode 510 and the negative electrode 520 and the concentration of electrolyte ions present between the positive electrode 510 or the negative electrode 520 and the housing can be solved.

As described above, the electrode assembly 500 according to the first embodiment of the present invention includes a positive electrode and a negative electrode current collector formed such that a plurality of holes are positioned on the same vertical line, and a positive electrode inserted into the holes of the positive and negative current collector. And by providing the negative active material, it is possible to improve the energy output characteristics by inducing the flow of the electrolyte solution through the plurality of holes, as well as increase the amount of the positive electrode and the negative electrode active material to improve the energy density.

9 is a cross-sectional view of an electrode assembly according to a second embodiment of the present invention.

Referring to FIG. 9, an electrode assembly 600 according to a second embodiment of the present invention is formed by sequentially stacking an anode 610, a separator 630, and a cathode 620. The electrode assembly 600 is processed into a Jelly-Roll type winding structure or a stack structure and accommodated in the housing together with the electrolyte solution 650.

The anode 610, the separator 630, and the cathode 620 of the electrode assembly 600 according to the present invention are the anode 510, the separator 530, and the cathode of the electrode assembly 500 shown in FIG. 8 described above. Since it is the same as or similar to 520, detailed descriptions of the anode 610, the separator 630, and the cathode 620 will be omitted, and the difference between the anode 510, the separator 530, and the cathode 520 Let's focus on the explanation.

The positive electrode 610 includes a positive electrode current collector 611 made of a metal foil and a positive electrode active material 613 made of porous activated carbon, and the negative electrode 620 is a negative current collector 621 made of a metal thin film and porous. And a negative active material 623 composed of activated carbon.

The positive and negative current collectors 611 and 621 may include a plurality of holes 640 having a size of about 10 μm to 200 μm. The plurality of holes 640 may be formed to have the same or similar size to each other, and may be formed to be disposed on the surfaces of the positive and negative current collectors 611 and 621 at regular intervals. In addition, the plurality of holes 640 may be formed to have a predetermined pattern on the surfaces of the positive and negative current collectors 611 and 621.

The plurality of holes 640 may be formed so that the first holes 640 formed in the positive electrode current collector 611 and the second holes 640 formed in the negative electrode current collector 621 are not located on the same vertical line, but are alternately located. I can. That is, the first holes 640 formed in the positive electrode current collector 611 may be formed to be positioned between the second holes 640 formed in the negative electrode current collector 621, and the second holes 640 formed in the negative electrode current collector 621 The holes 640 may be formed to be positioned between the first holes 640 formed in the positive electrode current collector 611.

The positive and negative active materials 613 and 623 may be uniformly applied and disposed on both surfaces of the positive and negative current collectors 611 and 621, as well as a plurality of positive and negative electrode current collectors 611 and 621. It may be inserted and disposed in the holes 640. To this end, during the coating and drying process of the active material, the active materials 613 and 623 are coated on both surfaces of the positive and negative current collectors 611 and 621, and then predetermined in a direction perpendicular to the surfaces of the current collectors 611 and 621. The active material may be inserted into the plurality of holes 640 by applying a pressure of. As the amount of the active materials 613 and 623 present in the positive electrode 610 and the negative electrode 620 increases through the hole insertion process, the energy density of the electrode assembly 600 increases.

The electrolyte solution 650 provides electrolyte ions (ie, cation/anion) adsorbed or desorbed on the positive electrode and negative electrode active materials 613 and 623 of the electrode assembly 600 when charging/discharging the energy storage device 100. Play a role. As shown in the drawing, since the electrolyte solution 650 has a property of permeating the porous active material and the separator, it can be moved in the direction of the arrow through the plurality of holes 640 formed in the positive and negative current collectors 611 and 621. There will be. Accordingly, an imbalance between the concentration of electrolyte ions present between the positive electrode 610 and the negative electrode 620 and the concentration of electrolyte ions present between the positive electrode 610 or the negative electrode 620 and the housing can be solved.

As described above, the electrode assembly 600 according to the second embodiment of the present invention includes a positive electrode current collector in which a plurality of first holes are formed, and a negative electrode in which a plurality of second holes are disposed to cross each other with the first holes. By providing a current collector and a positive and negative active material inserted into the holes of the positive and negative current collector, it is possible to induce the flow of electrolyte through the plurality of holes to improve energy output characteristics, as well as the positive and negative electrode active materials. Energy density can be improved by increasing the amount.

10 is a cross-sectional view of an electrode assembly according to a third embodiment of the present invention.

Referring to FIG. 10, an electrode assembly 700 according to a third embodiment of the present invention is formed by sequentially stacking an anode 710, a separator 730, and a cathode 720. The electrode assembly 700 is processed into a Jelly-Roll type winding structure or a stack structure, and accommodated in the housing together with the electrolyte 750.

The anode 710, the separator 730, and the cathode 720 of the electrode assembly 700 according to the present invention are the anode 510, the separator 530, and the cathode of the electrode assembly 500 shown in FIG. 8 described above. Since it is the same as or similar to 520, detailed descriptions of the anode 710, the separator 730, and the cathode 720 will be omitted, and the difference between the anode 510, the separator 530, and the cathode 520 Let's focus on the explanation.

The positive electrode 710 includes a positive electrode current collector 711 made of a metal foil and a positive active material 713 made of porous activated carbon, and the negative electrode 720 is a negative electrode current collector 721 made of a metal thin film and porous. And a negative active material 723 made of activated carbon.

As shown in FIG. 5, when the anode 710 is disposed on the top of the electrode assembly 700 wound in a cylindrical shape (ie, a cathode, a separator on the cathode, and an anode are sequentially stacked on the separator), A plurality of holes 740 having a size of about 10 μm to 200 μm may be formed in the positive electrode current collector 711 of the positive electrode 710. The plurality of holes 740 may be formed to have the same or similar size to each other, and may be formed to be disposed at regular intervals on the surface of the positive electrode current collector 711. In addition, the plurality of holes 740 may be formed to have a predetermined pattern on the surface of the positive electrode current collector 711.

On the other hand, although not shown in the drawing, when the cathode 720 is disposed on the top of the electrode assembly 700 wound in a cylindrical shape (that is, when the anode, the separator on the anode, and the cathode are sequentially stacked on the separator) , A plurality of holes 740 having a size of about 10 μm to 200 μm may be formed in the negative electrode current collector 721 of the negative electrode 720.

The negative active material 723 may be uniformly applied and disposed on both surfaces of the negative current collector 721. Meanwhile, the positive electrode active material 713 may be uniformly applied and disposed on both surfaces of the positive electrode current collector 711, and may be inserted and disposed in the plurality of holes 740 formed in the positive electrode current collector 711. have. To this end, during the coating and drying process of the active material, the active material 713 is coated on both surfaces of the positive electrode current collector 711 and then a predetermined pressure is applied in a direction perpendicular to the surface of the current collector 711 to obtain a plurality of active materials. It can be inserted into the holes 740 of. As the amount of the active material 713 present in the positive electrode 710 increases through the hole insertion process, the energy density of the electrode assembly 700 increases.

The electrolyte solution 750 provides electrolyte ions (ie, cation/anion) adsorbed or desorbed on the positive electrode and negative electrode active materials 713 and 723 of the electrode assembly 700 when charging/discharging the energy storage device 100. Play a role. As shown in the drawing, since the electrolyte solution 750 has a property of permeating the porous active material and the separator, it can move in the direction of the arrow through the plurality of holes 740 formed in the positive electrode current collector 711. Accordingly, an imbalance between the concentration of electrolyte ions present between the positive electrode 710 and the negative electrode 720 and the concentration of electrolyte ions present between the positive electrode 710 and the housing can be solved.

As described above, the electrode assembly 700 according to the third embodiment of the present invention includes a positive electrode current collector in which a plurality of holes are formed in a predetermined pattern and an active material inserted into the holes of the positive electrode current collector. By inducing the flow of the electrolyte through the holes of, not only can the energy output characteristics be improved, but also the energy density can be improved by increasing the amount of the active material.

11 is a cross-sectional view of an electrode assembly according to a fourth embodiment of the present invention.

Referring to FIG. 11, the electrode assembly 800 according to the fourth embodiment of the present invention is formed by sequentially stacking an anode 810, a separator 830, and a cathode 820. The electrode assembly 800 is processed into a Jelly-Roll type winding structure or a stack structure and accommodated in the housing together with the electrolyte solution 850.

The anode 810, the separator 830, and the cathode 820 of the electrode assembly 800 according to the present invention are the anode 510, the separator 530, and the cathode of the electrode assembly 500 shown in FIG. Since it is the same or similar to 520, detailed descriptions of the anode 810, separator 830, and cathode 820 will be omitted, and the difference between the anode 510, the separator 530, and the cathode 520 Let's focus on the explanation.

The positive electrode 810 includes a positive electrode current collector 811 made of a metal foil and a positive active material 813 made of porous activated carbon, and the negative electrode 820 is a negative electrode current collector 821 made of a metal thin film and porous. And a negative active material 823 made of activated carbon.

As shown in FIG. 5, when the anode 810 is disposed on the top of the electrode assembly 800 wound in a cylindrical shape (ie, a cathode, a separator over the cathode, and an anode is sequentially stacked on the separator), A plurality of holes 840 having a size of about 10 μm to 200 μm may be formed in the positive electrode current collector 811 of the positive electrode 810. The plurality of holes 840 may be formed to have the same or similar size to each other, and may be formed to be disposed at regular intervals on the surface of the positive electrode current collector 811.

Also, the plurality of holes 840 may be formed only in a partial area of the positive electrode current collector 811. For example, as shown in FIG. 5, the plurality of holes 811 may be formed only in the outermost region of the electrode assembly 800 wound in a cylindrical shape, that is, the positive electrode current collector region A facing the housing. have.

On the other hand, although not shown in the drawing, when the cathode 820 is disposed on the top of the electrode assembly 800 wound in a cylindrical shape (that is, when the anode, the separator on the anode, and the cathode are sequentially stacked on the separator) , A plurality of holes 840 having a size of about 10 μm to 200 μm may be formed in the negative electrode current collector 821 of the negative electrode 820. The plurality of holes 840 may be formed only in a partial area of the negative electrode current collector 821. The area occupied by the hole in the current collector should consider the overall capacity and charge/discharge characteristics. Therefore, if it is difficult to form a hole in the entire current collector, at least the outermost current collector surface is formed with a hole, so that the electrolyte between the outermost current collector surface and the housing where depletion of ions occurs relatively little, the electrolyte Can secure the path of movement. Accordingly, it is possible to solve an imbalance between the concentration of electrolyte ions existing between the positive electrode 710 and the negative electrode 720 and the concentration of the electrolyte between the outermost current collector surface and the housing.

The negative active material 823 may be uniformly applied and disposed on both surfaces of the negative electrode current collector 821. Meanwhile, the positive active material 813 may be uniformly applied and disposed on both surfaces of the positive electrode current collector 811, and may be inserted and disposed in the plurality of holes 840 formed in the positive electrode current collector 811. have. To this end, during the coating and drying process of the active material, the active material 813 is coated on both surfaces of the positive electrode current collector 811 and then a predetermined pressure is applied in a direction perpendicular to the surface of the current collector 811 to obtain a plurality of active materials. It can be inserted into the holes 840 of. As the amount of the active material 813 present in the positive electrode 810 increases through the hole insertion process, the energy density of the electrode assembly 800 increases.

The electrolyte solution 850 provides electrolyte ions (i.e., cation/anion) adsorbed or desorbed on the positive electrode and negative electrode active materials 813 and 823 of the electrode assembly 800 when charging/discharging the energy storage device 100. Play a role. As shown in the drawing, since the electrolyte solution 850 has a property of permeating the porous active material and the separator, it can move in the direction of the arrow through the plurality of holes 840 formed in the positive electrode current collector 811. Accordingly, an imbalance between the concentration of electrolyte ions existing between the positive electrode 810 and the negative electrode 820 and the concentration of electrolyte ions existing between the positive electrode 810 and the housing can be solved.

As described above, the electrode assembly 800 according to the fourth embodiment of the present invention includes a positive electrode current collector in which a plurality of holes are formed in a partial region, and a positive electrode active material inserted into the holes of the positive electrode current collector. By inducing the flow of the electrolyte through the holes of, not only can the energy output characteristics be improved, but also the energy density can be improved by increasing the amount of the active material.

Meanwhile, although specific embodiments of the present invention have been described above, various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention is not limited to the described embodiments, and should be defined by the claims and equivalents as well as the claims to be described later.

100: energy storage device 110: electrode assembly
111: anode 112: cathode
113: separator 120: housing
122: upper housing 124: lower housing
130: electrode terminal 132: positive terminal
134: negative terminal

Claims (11)

A positive electrode including a positive electrode current collector made of a metal foil and a positive electrode active material coated on both surfaces of the positive electrode current collector;
A negative electrode including a negative electrode current collector made of a metal thin film and a negative electrode active material coated on both surfaces of the negative electrode current collector; And
An electrode assembly disposed between the anode and the cathode and including a separator electrically separating the anode and the cathode,
At least one of the positive electrode current collector and the negative electrode current collector of the electrode assembly includes a plurality of holes having a size in a predetermined range, and at least one of the positive electrode active material and the negative electrode active material is inserted and disposed in the plurality of holes Energy storage device. The method of claim 1,
The energy storage device, characterized in that the positive and negative current collectors are formed to have a roughening ratio in the range of 5% to 10%. The method of claim 1,
The energy storage device, characterized in that the positive and negative current collectors are formed to have a thickness of 20 µm to 30 µm. The method of claim 1,
The energy storage device, characterized in that the positive and negative current collectors are formed to have a tension of 1.3 kg/cm or more. The method of claim 1,
The energy storage device, characterized in that the plurality of holes are formed to have a size of 10㎛ to 200㎛. The method of claim 1,
The plurality of holes are energy storage device, characterized in that arranged at regular intervals on the surface of the current collector. The method of claim 1,
The plurality of holes are composed of first holes formed in the positive current collector and second holes formed in the negative current collector,
The energy storage device, wherein the first and second holes are formed to face each other based on the separation membrane. The method of claim 1,
The plurality of holes are composed of first holes formed in the positive current collector and second holes formed in the negative current collector,
Wherein the first holes are formed to be located between second holes formed in the negative current collector, and the second holes are formed to be located between first holes formed in the positive current collector. The method of claim 1,
When the anode is disposed at the top of the electrode assembly wound in a cylindrical shape, the plurality of holes are formed only in the anode assembly of the anode. The method of claim 1,
When the cathode is disposed at the top of the electrode assembly wound in a cylindrical shape, the plurality of holes are formed only in the cathode assembly of the cathode. The method of claim 9 or 10,
The plurality of holes are formed in a current collector region corresponding to the outermost region (A) of the electrode assembly wound in a cylindrical shape.

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