Dry electrode manufacturing method and dry electrode manufacturing system

Abstract

The present invention relates to a method and system for manufacturing a dry electrode, and the method for manufacturing a dry electrode of the present invention includes the steps of: (S10) forming a primer layer having a predetermined width on at least one surface of a current collector; (S20) forming dams on both side surfaces in the width direction of the primer layer to prevent electrode powder from flowing off; (S30) supplying electrode powder to the surface of the primer layer; and (S40) compressing the electrode powder to form an electrode active material layer.

Description

[Technical Field]

[0001] The present invention relates to a method and system for manufacturing a dry electrode using a powder coating method.

[0002] This application claims priority based on Korean Patent Application No. 2022-0185089, filed on December 26, 2022, and the entire contents disclosed in the specification of that application are incorporated herein by reference. [Background technology]

[0003] The rapid increase in fossil fuel use has led to a growing demand for alternative and clean energy. One of the most actively researched areas in this field is electrochemical power generation and storage. Currently, secondary batteries are a representative example of electrochemical devices that utilize such electrochemical energy, and their range of use is expanding. Among these secondary batteries, lithium secondary batteries are not only used as an energy source for mobile devices, but have also recently been realized as a power source for electric vehicles and hybrid electric vehicles that can replace fossil fuel-powered vehicles such as gasoline and diesel vehicles, which are one of the major causes of air pollution. Their range of use is also expanding as an auxiliary power source for grid-connected power sources.

[0004] In such a lithium secondary battery, the electrode manufacturing process is divided into an electrode material mixing process, an electrode coating process, a drying process, a pressing process, a slitting process, a winding process, etc., and among these, the electrode material mixing process is a process of blending components for forming an electrode active material layer, and the electrode active material, electrode materials such as a binder, and a solvent are mixed to prepare a fluid slurry.

[0005] Thereafter, an electrode coating process is performed in which the electrode material prepared in a slurry form is applied onto a current collector, a drying process is performed to remove the solvent, and a pressing process is performed to manufacture an electrode of a predetermined thickness.

[0006] Meanwhile, evaporation of the solvent during the drying process may cause defects such as pinholes and cracks in the electrode active material layer. Furthermore, if the inside and outside of the electrode active material layer are not dried uniformly, a powder floating phenomenon may occur due to the difference in the evaporation rate of the solvent, i.e., powder in the first dried area may float up, forming a gap between the first dried area and the second dried area, thereby degrading the quality of the electrode.

[0007] To solve these problems, active research has recently been conducted into the production of dry electrodes without using solvents.

[0008] Dry electrodes are generally manufactured by preparing an electrode powder containing an electrode active material and a binder resin, applying the powder to the surface of a current collector, and then pressing the powder onto the surface. Compared to electrodes manufactured using a slurry coating method, dry electrodes manufactured using a dry manufacturing method have the advantage of having a more uniform binder resin distribution in the thickness direction of the electrode active material layer and fewer defects such as pinholes and cracks. However, when applying the electrode powder to the current collector, the electrode powder may flow off the edge of the electrode active material layer or protrude from the edge of the electrode active material layer during pressing, which can result in an uneven finish on the side surface.

[0009] Therefore, there is an urgent need to develop a dry electrode manufacturing technology that can solve these problems. Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a method for manufacturing a dry electrode that can improve the quality of the side portion of the electrode active material layer.

[0011] Another object of the present invention is to provide a dry electrode manufacturing system capable of improving the quality of the side portion of the electrode active material layer.

[0012] It will be readily apparent that other objects and advantages of the present invention can be achieved by the means or methods recited in the claims and combinations thereof. [Means for solving the problem]

[0013] According to one aspect of the present invention, there is provided a method for producing a dry electrode according to the following embodiment.

[0014] The method for producing a dry electrode according to the first aspect includes: (S10) forming a primer layer having a predetermined width on at least one surface of a current collector; (S20) forming dams on both side surfaces of the primer layer in the width direction to prevent the electrode powder from flowing off; (S30) supplying electrode powder to the surface of the primer layer; (S40) compressing the electrode powder to form an electrode active material layer;

[0015] According to the second aspect, in the first aspect, The dam can be formed so as to protrude from the surface of the current collector to a height greater than the height of the primer layer and to be in close contact with the side surface of the primer layer without being spaced apart from it.

[0016] According to the third aspect, in the first or second aspect, (S50) After performing step (S40), the method may further include a step of removing the electrode active material layer existing outside the dam.

[0017] According to a fourth aspect, in any one of the first to third aspects, The step (S50) can be performed by laser irradiation or knife-type etching.

[0018] According to a fifth aspect, in any one of the first to fourth aspects, The dam may be made of a material that does not change the physical and chemical properties of the primer layer and the electrode powder even when it comes into contact with the primer layer and the electrode powder.

[0019] According to a sixth aspect, in any one of the first to fifth aspects, The dam may comprise a polymeric material.

[0020] According to a seventh aspect, in any one of the first to sixth aspects, The step (S20) can be performed by a printing method.

[0021] According to an eighth aspect, in any one of the first to seventh aspects, The electrode powder may include an electrode active material and an electrode binder resin.

[0022] According to a ninth aspect, in any one of the first to eighth aspects, The electrode powder can be produced by a spray drying method.

[0023] According to a tenth aspect, in any one of the first to ninth aspects, The primer layer may include a conductive material for a primer layer and a binder resin for a primer layer.

[0024] According to another aspect of the present invention, there is provided a dry electrode having the following configuration.

[0025] A dry electrode according to an eleventh aspect comprises: The electrode active portion includes a current collector and an electrode active portion formed on at least one surface of the current collector, the electrode active portion including a primer layer and an electrode active material layer formed on the primer layer, and a dam may be formed to cover the entire circumference of a side portion of the electrode active portion or at least a portion of the entire circumference of the side portion.

[0026] According to the twelfth aspect, in the eleventh aspect, The dam may be formed to the same height as or lower than the electrode active portion.

[0027] According to the thirteenth aspect, in the eleventh or twelfth aspect, The dam may be made of a material that does not change the physical and chemical properties of the primer layer and the electrode powder even when it comes into contact with the primer layer and the electrode powder. [Effects of the Invention]

[0028] According to the dry electrode manufacturing method of the present invention, when applying the electrode powder, the electrode powder does not flow off due to the dams formed on both ends of the electrode active material layer in the width direction, thereby achieving the effect of controlling the edge shape to a constant shape.

[0029] Therefore, according to the dry manufacturing method of the present invention, since the electrode powder does not come off from the edge of the electrode during the calendaring process, it is possible to form an electrode active material layer having a uniform and smooth edge shape.

[0030] Therefore, the dry manufacturing method of the present invention has the effect of providing a high-quality dry electrode.

[0031] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the above-described content of the invention, serve to further understand the technical concept of the present invention, and the present invention should not be interpreted as being limited to only the matters depicted in such drawings. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 10 is a schematic diagram illustrating a comparative example of manufacturing a dry electrode without a dam. [Figure 2] FIG. 2 is a diagram schematically illustrating a state in which a primer layer is formed on the surface of a current collector. [Figure 3a]1 is a schematic side view of an electrode having dams on both ends of a primer layer in a method for manufacturing a dry electrode according to an embodiment of the present invention; FIG. [Figure 3b] 3b is a schematic diagram illustrating a top view of an electrode having dams on both ends of a primer layer in a dry electrode manufacturing method according to an embodiment of the present invention. In one embodiment of the present invention, the dams may be formed parallel to the running direction of the process during electrode manufacturing. [Figure 4] 2 is a schematic view illustrating an electrode powder applied between dams in a method for manufacturing a dry electrode according to an embodiment of the present invention; FIG. [Figure 5] 3 is a diagram illustrating a state in which an electrode active material layer is formed by pressing the applied electrode powder in a dry electrode manufacturing method according to an embodiment of the present invention. FIG. [Figure 6] 6 is a diagram illustrating a process of removing the electrode active material layer 104 protruding from the outer side of the dam 121 by irradiating a laser in a method for manufacturing a dry electrode according to an embodiment of the present invention. Referring to FIG. 6, according to an embodiment of the present invention, the dam can be partially or entirely removed by irradiating the laser 201. [Figure 7] FIG. 1 is a schematic diagram illustrating a method for manufacturing a dry electrode by a roll-to-roll continuous process in one embodiment of the present invention. [Figure 8] 8 is a diagram showing a process of performing a step of removing the electrode active material layer protruding outside the dam by laser irradiation (S50) according to one embodiment of the present invention. The arrows at the top of FIG. 8 indicate the process direction of the electrode in the manufacturing process. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention will be described in detail below. However, the present invention is not limited to the following content, and each component may be variously modified or selectively combined as necessary. Therefore, it should be understood that the present invention includes all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention.

[0034] Throughout this specification, when a part is described as "comprising" a certain component, this does not mean that other components are excluded, and means that other components may also be included, unless otherwise specified.

[0035] Furthermore, the terms "about," "substantially," and the like used throughout this specification mean a value at or close to the stated value when manufacturing and material tolerances are given, and are used to prevent unscrupulous infringers from unfairly exploiting the contents of the disclosure in which precise or absolute values ​​are stated to aid in the understanding of the present invention.

[0036] Throughout this specification, the phrase "A and / or B" means "A or B or both."

[0037] Certain terminology used herein is for convenience only and is not limiting. For example, terms such as "top," "bottom," "left," "right," "front," "rear," "inside," and "outside" are used to describe relative positions and orientations of components relative to one another, or may represent positions and orientations in the drawings to which reference is made, rather than absolute positions. These terms include themselves as well as words containing them, their derivatives, and words of similar import.

[0038] As used herein, "glass transition temperature (Tg)" can be measured by conventional methods known to those skilled in the art, for example, by differential scanning calorimetry (DSC).

[0039] As used herein, the term "porosity" refers to the ratio of the volume occupied by pores to the total volume of a structure, and is expressed in units of vol%. It may be used interchangeably with terms such as void ratio and porosity. In the present invention, the measurement of the porosity is not limited to any particular method, and according to one embodiment of the present invention, for example, the porosity may be measured by the Brunauer-Emmett-Teller (BET) measurement method using nitrogen gas or by mercury penetration (Hg porosimeter) in accordance with ASTM D-2873. Alternatively, the true density of the separator may be calculated from the density (apparent density) of the separator, the composition ratio of the materials contained in the separator, and the density of each component, and the porosity of the separator may be calculated from the difference between the apparent density and the true density (net density).

[0040] As used herein, the term "average particle size (D 50 )" means the particle size at 50% of the cumulative distribution of the number of particles according to particle size, and the particle size can be measured using a laser diffraction method. Specifically, the powder to be measured is dispersed in a dispersion medium, and then the powder is taken into a commercially available laser diffraction particle size distribution analyzer (e.g., Microtrac S3500). When the particles pass through a laser beam, the difference in the diffraction pattern according to the particle size is measured to calculate the particle size distribution. By calculating the diameter of the particles at 50% of the cumulative distribution of the number of particles according to particle size in the measuring device, D 50 The particle size can be measured.

[0041] The "thickness" of each layer included in the electrode in this specification may refer to a value measured by a known method for measuring thickness. The method for measuring thickness is not limited thereto, but may be, for example, a value measured using a thickness measuring instrument (VL-50S-B manufactured by Mitutoyo Corporation).

[0042] The "specific surface area" used in this specification may refer to a value measured by a known method for measuring specific surface area. The measurement method for specific surface area is not limited thereto, but may be, for example, a value measured by a flow method or a stationary method.

[0043] Next, the method for producing the dry electrode will be described in more detail.

[0044] <Dry electrode manufacturing method> In the present invention, the dry electrode manufacturing method refers to a method for manufacturing an electrode, which includes a step of preparing an electrode powder in a powder state and pressing the electrode powder to form an electrode active material layer.

[0045] In addition, in the present invention, the dry electrode means an electrode manufactured by the method for manufacturing a dry electrode.

[0046] The dry electrode and the method for manufacturing the dry electrode are different from an electrode manufacturing method and an electrode manufactured thereby in which an electrode material is mixed with a solvent to prepare a wet intermediate product such as a slurry, which is then applied to the surface of a current collector and dried, and the dry electrode and the method for manufacturing the dry electrode do not involve a solvent during the electrode manufacturing process.

[0047] Meanwhile, in the present invention, the dry electrode is an electrode for an electrochemical device, and the electrochemical device may include any device that performs an electrochemical reaction. Specific examples include any type of primary battery, secondary battery, fuel cell, solar cell, or capacitor such as a supercapacitor device. In the present invention, the electrochemical device may preferably be a secondary battery, more preferably a lithium ion battery.

[0048] A method for manufacturing a dry electrode according to one aspect of the present invention includes: (S10) forming a primer layer having a predetermined width on at least one surface of a current collector; (S20) forming dams on both side surfaces of the primer layer in the width direction to prevent the electrode powder from flowing off; (S30) supplying electrode powder to the surface of the primer layer; (S40) compressing the electrode powder to form an electrode active material layer;

[0049] Each step will be explained in detail below.

[0050] (S10) First, a current collector is prepared, and a primer layer having a predetermined width is formed on one or both surfaces of the current collector (S10).

[0051] The current collector is not particularly limited as long as it has high conductivity and does not cause chemical changes in the battery. In one embodiment of the present invention, the current collector can be made of, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, copper, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, or the like. The current collector can also have fine irregularities on its surface to enhance adhesion of the electrode active material, and can be in various forms such as a film, sheet, foil, net, porous material, foam, or nonwoven fabric.

[0052] The current collector includes a plain area on all or part of its edge where no primer layer / electrode active material layer is formed and the surface is exposed. The plain area may be used as an electrode tab by itself or may be connected to a separate electrode tab.

[0053] 2 is a schematic cross-sectional view of a structure in which a primer layer and a dam are formed on the surface of a current collector during a process for manufacturing a dry electrode according to one embodiment of the present invention. Referring to the figure, uncoated areas having a predetermined width are formed inward from both widthwise edges on one surface of the current collector, and a primer layer is formed between the uncoated areas.

[0054] According to an embodiment of the present invention, the primer layer may include a conductive material and a binder resin. The primer layer will be described in detail below.

[0055] (S20) Next, dams are formed on both side surfaces of the primer layer in the width direction to prevent the electrode powder from flowing off (S20).

[0056] FIG. 1 is a schematic flow chart of a method for manufacturing an electrode using electrode powder, without a dam-forming step. Referring to FIG. 1, electrode powder 103 is applied to a primer layer 102 formed on one surface of a current collector 101 to prepare an electrode active material layer 104. During the feeding process 400, which applies the electrode powder, problems can arise in that the electrode powder flows out of the primer layer. Furthermore, during the sheeting process 500, pressure can cause the electrode powder to detach from the primer layer, resulting in the formation of an electrode active portion 111. When laser irradiation is performed in the subsequent edge cleaning process 600 to etch and smooth the edges of the electrode active material layer 104 that have detached from the primer layer, the laser can reach the current collector 101, the primer layer 102, and the like, causing damage to undesired areas 200.

[0057] According to one aspect of the present invention, it is possible to provide a method for manufacturing a dry electrode that can solve such problems.

[0058] 3a and 3b are schematic side and top views, respectively, of an electrode having dams 121 formed at both ends of the width of a primer layer 102 formed on one surface of a current collector 101 in a dry electrode manufacturing method according to one embodiment of the present invention.

[0059] Referring to Figures 3a and 3b, the dam 121 may be formed only in at least a portion of the side of the primer layer 102, but from the viewpoint of uniformity in the quality of the electrode side, it may be preferable to form it over the entire side of the primer layer.

[0060] In addition, in an embodiment of the present invention, the width of the dam may be smaller than the width of the uncoated portion.

[0061] In one embodiment of the present invention, it is preferable that the dam is in close contact with the side portion of the primer layer without being spaced apart, so that the electrode powder does not flow between the primer layer and the dam when the electrode powder is applied in a later step.

[0062] In one embodiment of the present invention, the dam may be formed to a height equal to or lower than the height of the electrode active portion.

[0063] In this specification, the electrode active part refers to a structure formed by laminating the primer layer and the electrode active material layer.

[0064] The dam can control the position of the electrode powder so that the electrode powder is fixed to the top of the primer layer and does not escape to the outside of the primer layer when the electrode powder is applied to the top of the primer layer. Therefore, the dam preferably protrudes outward from the surface of the current collector and is formed at a position higher than the height of the primer layer.

[0065] Meanwhile, in the present invention, the dam is preferably made of a material that does not change the physical and chemical properties of the primer layer and the electrode powder even when it comes into contact with the primer layer and the electrode powder.

[0066] In one embodiment of the present invention, the dam is not a battery component involved in electrochemical activity, but may simply be used as a means to assist the electrode in maintaining a predetermined shape during electrode fabrication. Therefore, it is preferable that the dam does not damage the electrode or exert a physical / chemical effect on electrode materials such as the electrode active material.

[0067] In one embodiment of the present invention, the dam may contain at least one of an insulating polymer material and an inorganic material. For example, the dam may contain 90 wt % or more of the insulating polymer material and the inorganic material relative to 100 wt %, or the dam may be formed only from the insulating polymer material and / or the inorganic material.

[0068] Examples of the insulating polymeric material include, but are not limited to, polyethylene (PE), polypropylene (PP), polybutylene (PB), polystyrene (PS), polyethylene terephthalate (PET), natural rubber, and synthetic rubber.

[0069] The inorganic material is not particularly limited as long as it does not undergo oxidation and / or reduction reactions within the operating voltage range of the battery (e.g., 0 to 5 V based on Li / Li+) and is electrochemically stable. Non-limiting examples of the inorganic material include BaTiO3, Pb(Zr,Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg3Nb 2 / 3 )O3-PbTiO3 (PMN-PT), hafnia (HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, and SiC, and may contain one or more selected from these, but is not limited to these.

[0070] 3a is a schematic diagram of the electrode side view showing the dams formed on both ends of the primer layer in the width direction, which shows that the height of the dams is higher than the height of the primer layer.

[0071] 3b is a plan view showing a state in which a primer layer and a dam are formed on the surface of a current collector. Referring to this, uncoated areas having a predetermined width are formed on both ends of the current collector in the width direction, a primer layer is disposed between the uncoated areas, and dams are disposed on both ends of the primer layer in close contact with the primer layer.

[0072] The structure shown in Figure 3b is a schematic diagram of a long strip-shaped sheet manufactured by a roll-to-roll continuous process, which can be cut at predetermined intervals after electrode manufacturing to be used as unit electrodes of a predetermined size, or can be wound up together with a strip-shaped separator and counter electrode to manufacture a jelly-roll structured electrode assembly.

[0073] In one embodiment of the present invention, the width of the dam may be determined in consideration of the size of the electrode powder.

[0074] For example, the average particle size (D 50 ) is d1, the width of the dam can be configured to satisfy, for example, 0.80d1≦dam width≦1.20d1.

[0075] In one embodiment of the present invention, as described below, the electrode powder may have a particle size in the range of 0.1 to 1,000 μm. For example, the average particle size (D 50 ) can be 10 μm to 500 μm, specifically 15 μm to 200 μm, 15 μm to 100 μm, 30 μm to 80 μm, 40 μm to 60 μm, 45 μm to 55 μm, or 45 μm to 50 μm.

[0076] In one embodiment of the present invention, the dam may be formed to have a width of up to 100 μm.

[0077] In an embodiment of the present invention, the height of the dam may be determined in consideration of the height of the electrode active portion.

[0078] For example, the height of the dam may be preferably formed higher than the height of the primer layer, and may be preferably formed lower than the height of the electrode active material layer in consideration of the subsequent rolling process of the electrode active material layer.

[0079] In one embodiment of the present invention, the dam may be formed to a maximum height of 50 μm. However, the width and height of the dam are not particularly limited to this range and may be set to an appropriate range taking into consideration the width of the current collector, the width and height of the electrode active material layer, the particle size of the electrode powder, etc.

[0080] Meanwhile, in one embodiment of the present invention, the dam may be formed by applying a dam-forming ink (dam-forming composition) to the side of the primer layer using a coating device such as an inkjet printer.

[0081] In this case, the dam is preferably formed so as to be in close contact with the side surface of the primer layer without being spaced apart from it.

[0082] (S30) Next, electrode powder is supplied onto the surface of the primer layer (S30).

[0083] 7, a current collector having a primer layer and a dam formed thereon is supplied to a dry electrode manufacturing process by a roll-to-roll continuous process, and electrode powder is supplied to the surface of the primer layer through an electrode powder supplying device (feeder) 401 (feeding process 400). When applying the electrode powder, the dam limits the space in which the electrode powder can be placed, so that the electrode powder can be attached to the surface of the primer layer without escaping outside the primer layer.

[0084] FIG. 4 is a diagram schematically showing the shape of an electrode active portion 111 formed by a dam so that the electrode powder is not separated but is arranged on the surface of the primer layer.

[0085] The electrode powder supplying device may be a supplying device such as a screw feeder, but is not particularly limited thereto.

[0086] Meanwhile, in one embodiment of the present invention, the electrode powder may be spread on a current collector, and the electrode powder may be uniformly formed with a blade or the like to adjust the thickness, and then the electrode powder may be applied to a pressurizing device.

[0087] (S40) Next, the electrode powder is compressed to form a layered electrode active material layer (S40).

[0088] In one embodiment of the present invention, the step (S40) may be performed in a manner in which the electrode powder is compressed by a pair of sheeting rolls.

[0089] Referring to FIG. 5, the electrode powder is compressed by pressure, and the electrode powder particles are brought into close contact with each other to form an electrode active material layer, and the total volume (apparent volume) decreases and the density increases compared to before compression.

[0090] In this step, the dams fix the shape of the electrode active material layer at both ends of the electrode active material layer in the width direction, which prevents the electrode powder from detaching to the outside of the primer layer when pressure is applied, or has the effect of reducing the number of electrode powder particles that detach.

[0091] As a result, the applied electrode powder is entirely contained in the formed electrode active material layer, which has the effect of preventing a decrease in the energy density of the electrode.

[0092] Meanwhile, referring to FIG. 7, after the electrode powder is applied to the surface of the primer layer, it is pressed while passing between a pair of sheeting rolls 501 in a sheeting process 500 to form a layered electrode active material layer.

[0093] In one embodiment of the present invention, the pressing can be carried out two or more times as necessary to eliminate variations in the thickness of the formed electrode and increase the density of the electrode active material layer to achieve a high capacity.

[0094] In one embodiment of the present invention, in the roll press process using pressure rollers, two cylindrical rolls are arranged parallel to each other with a narrow gap between them, and are rotated in opposite directions to sandwich the electrode between them to apply pressure. The temperature of the rolls can also be adjusted by heating or cooling.

[0095] During the pressure application, the temperature of the electrode powder and / or electrode active material layer can be controlled, for example, within a range of 0°C to 20°C. The temperature control can be transmitted to the electrode powder and / or electrode active material layer by a pressure roller. The temperature can be preferably higher than the melting point or glass transition temperature of the electrode binder resin, and more preferably 20°C or more higher than the melting point or glass transition temperature. The molding speed in the pressure molding can usually be 0.1 to 20 m / min, or 1 to 10 m / min. The linear pressure between the rolls can usually be 0.2 to 30 kN / cm, or 0.5 to 10 kN / cm.

[0096] (S50) Meanwhile, in a specific embodiment of the present invention, after performing step (S40), a step of trimming the side surface of the electrode active material layer may be further performed, which may also be referred to as an edge cleaning process in this specification.

[0097] The trimming may be performed to remove electrode powder that has detached to the outside of the space defined by the dam during the pressing in the above-mentioned step, and / or to reduce the surface roughness of the side surface of the electrode active material layer and make it uniform.

[0098] In one embodiment of the present invention, the step (S50) may be performed to remove the electrode active material layer protruding outward from the dam after the step (S40) is performed.

[0099] In one embodiment of the present invention, the trimming may be performed by laser irradiation. However, the present invention is not limited to laser irradiation, and any other trimming method that can perform trimming without damaging the electrode active material layer may be used. When performing a surface trimming process using a method such as laser irradiation, the metal thin film used as the current collector may be deteriorated by the laser irradiation. However, in the dry electrode manufacturing process according to the present invention, a dam is formed on the surface of the current collector, preventing damage to the current collector caused by direct irradiation of the laser. Another method that can be used is, for example, a knife-type etching method. For example, the knife-type etching method may be performed by cutting the unevenly coated area of ​​the electrode powder with a blade and then removing the cut area using an air knife and suction. In this case, the blade may be a rotating circular blade, but the present invention is not limited thereto.

[0100] In one embodiment of the present invention, the laser irradiation may be performed on both sides of the side portion of the sheet-like dry electrode, or may be performed first on one side of the side portion and then on the other side, or may be performed on both sides simultaneously.

[0101] Referring to FIG. 8, laser irradiation can be performed on both sides of the side surface of the sheet-type dry electrode.

[0102] At this time, the side surface of the electrode active material layer may be trimmed during the laser irradiation to prevent excessive unevenness from being formed.

[0103] <Electrode powder> In the present invention, the electrode powder refers to a powdery material containing composite particles containing an electrode active material and an electrode binder resin, wherein the composite particles are formed by binding the electrode active material with the electrode binder resin.

[0104] In one embodiment of the present invention, the electrode active material may be contained in an amount of 80 wt% or more or 90 wt% or more of the total weight of the electrode powder, and the electrode binder resin may be contained in an amount of 20 wt% or less or 10 wt% or less of the total weight of the electrode powder.

[0105] Meanwhile, in one embodiment of the present invention, the electrode powder may further contain, as necessary, an electrode conductive material, which may be contained in an amount of 10 wt % or less relative to 100 wt % of the electrode powder.

[0106] Meanwhile, in one embodiment of the present invention, the electrode powder may have an aspect ratio (length-to-width ratio) of 0.5 to 1.0. The aspect ratio refers to the ratio of the average minor axis length to the average major axis length of the electrode powder, where the average minor axis length indicates the average length of the electrode powder in the shortest axis direction, and the average major axis length indicates the average length of the electrode powder in the longest axis direction. When the aspect ratio of the composite particles satisfies this range, it is advantageous in that the electrode powder has sufficient fluidity suitable for processing.

[0107] Meanwhile, in one embodiment of the present invention, the particle size of the electrode powder may be in the range of 0.1 to 1,000 μm.

[0108] In one specific embodiment, the average particle size (D 50 ) can be 10 μm to 500 μm, specifically 15 μm to 200 μm, 15 μm to 100 μm, 30 μm to 80 μm, 40 μm to 60 μm, 45 μm to 55 μm, or 45 μm to 50 μm.

[0109] In another embodiment, the average particle size (D 50 ) can be in the range of 50 μm to 500 μm, or 50 μm to 100 μm.

[0110] <Dry electrode structure> The present invention relates to a dry electrode obtained by the above-described method for producing a dry electrode.

[0111] The dry electrode includes a current collector and an electrode active portion formed on at least one surface of the current collector.

[0112] The electrode active part includes a primer layer and an electrode active material layer formed on the primer layer.

[0113] The electrode active portion has the dam formed on the entire periphery or at least a portion of the side surface thereof.

[0114] The dam is preferably disposed in close contact with the side surface of the electrode active portion without being spaced apart from the side surface.

[0115] In one embodiment of the present invention, the dam may be formed to the same height as or lower than the electrode active portion.

[0116] In one embodiment of the present invention, the dam may be preferably formed to a height lower than the height of the electrode active portion in consideration of a subsequent process of pressing the electrode active material layer.

[0117] Referring to FIG. 6, the dry electrode has an electrode active part formed by sequentially stacking a primer layer and an electrode active material layer on the surface of a current collector, and dams having a predetermined thickness are disposed closely on the side of the electrode active part.

[0118] <Electrode active material layer> In one embodiment of the present invention, the electrode active material layer includes an electrode active material and an electrode binder resin. As described above, these electrode materials may be included in the form of the composite particles.

[0119] In one embodiment of the present invention, the electrode active material layer may contain 95 wt % or more of the electrode powder relative to 100 wt % of the electrode active material layer, and the electrode active material layer may further contain free electrode active material particles derived from the electrode powder and / or an electrode binder resin.

[0120] Meanwhile, in one embodiment of the present invention, the electrode active material layer may further include an electrode conductive material. The electrode conductive material may be contained in electrode powder or may be free electrode conductive material particles.

[0121] The electrode active material layer is formed by accumulating the electrode powder in a layered structure, and has pores provided by interstitial volumes, which are spaces between the electrode powder particles, and exhibits porous properties derived from such a structure.

[0122] In one embodiment of the present invention, the electrode active material layer preferably has a porosity of 20 vol % to 40 vol % in consideration of electrolyte impregnation, dimensional stability, ionic conductivity, and the like.

[0123] <Electrode material> In an embodiment of the present invention, when the dry electrode is used as a positive electrode, the electrode powder may include a positive electrode active material.

[0124] The positive electrode active material is not limited to a lithium transition metal oxide or a lithium metal iron phosphate, as long as it is in the form of a metal oxide, for example, a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; 1+x Mn 2-x O4 (where x is 0 to 0.33), lithium manganese oxides such as LiMnO3, LiMn2O3, and LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiV3O4, V2O5, and Cu2V2O7; and the chemical formula LiNi 1-x M x Ni-site lithium nickel oxide represented by the chemical formula LiMnO2 (where M=Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x=0.01 to 0.3). 2-x M xLithium manganese composite oxide represented by O2 (where M = Co, Ni, Fe, Cr, Zn or Ta and x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu or Zn); part of Li in the chemical formula is substituted with aluminum ions, Li 1+x (Ni a Co b Mn c Al d ) 1-x O2 (x = 0 to 0.03, a = 0.3 to 0.95, b = 0.01 to 0.35, c = 0.01 to 0.5, d = 0.001 to 0.03, a + b + c + d = 1); lithium metal phosphate LiMPO4 (where M is M = Fe, CO, Ni, or Mn), disulfide compound; examples include, but are not limited to, Fe2(MoO4)3.

[0125] In another embodiment of the present invention, when the dry electrode is used as a negative electrode, the electrode powder may contain a negative electrode active material.

[0126] Examples of the negative electrode active material include carbon such as graphitizable carbon and graphite-based carbon; Li x Fe2O3 (0 ≤ x ≤ 1), Li x WO2 (0 ≤ x ≤ 1), Sn x Me 1-x Me’ y O z (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8) and other metal composite oxides; lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; silicon-based oxides such as SiO, SiO / C, SiO2; metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials; etc. can be used, but are not limited to these.

[0127] The conductive material for electrodes is not particularly limited as long as it does not cause a chemical change in the battery and has conductivity. Examples of the conductive material that can be used include graphite such as natural graphite and artificial graphite; carbon blacks such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber and metal fiber; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskeys such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives. In particular, the conductive material for electrodes may include one or more selected from the group consisting of activated carbon, graphite, carbon black, and carbon nanotubes in order to achieve uniform mixing of the conductive material for electrodes and improve conductivity. More particularly, the conductive material may include activated carbon.

[0128] In the present invention, the electrode binder resin is not particularly limited as long as it is used as a binder material for electrochemical elements, and may include, for example, a diene-based polymer, an acrylate-based polymer, a fluorine-based polymer, a styrene-based polymer, or two or more of these.

[0129] Examples of the diene polymer include polymers containing monomer units derived from conjugated dienes such as butadiene and isoprene, and hydrogenated products thereof. The proportion of the monomer units derived from conjugated dienes in the diene polymer is usually 40 wt % or more, preferably 50 wt % or more, and more preferably 60 wt % or more.

[0130] Specific examples include conjugated diene homopolymers such as polybutadiene and polyisoprene; aromatic vinyl-conjugated diene copolymers such as styrene-butadiene copolymer (SBR) which may be carboxy-modified; vinyl cyanide-conjugated diene copolymers such as acrylonitrile-butadiene copolymer (NBR); hydrogenated SBR; and hydrogenated NBR.

[0131] The styrene polymer is a polymer having a repeating unit derived from a styrene monomer, and examples thereof include a styrene homopolymer (polystyrene) and a styrene copolymer.

[0132] Examples of the styrene copolymer include block copolymers such as styrene-ethylene-butadiene copolymer, styrene-butadiene-propylene copolymer, styrene-isoprene copolymer, styrene-n-butyl acrylate-itaconic acid-methyl methacrylate-acrylonitrile copolymer, styrene-n-butyl acrylate-itaconic acid-methyl methacrylate-acrylonitrile copolymer, styrene-butadiene block copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer, styrene-isoprene block copolymer, and styrene-ethylene-propylene-styrene block copolymer.

[0133] Examples of the acrylate polymer include polymers containing monomer units derived from acrylic acid esters and / or methacrylic acid esters, and the proportion of the monomer units derived from acrylic acid esters and / or methacrylic acid esters in the acrylate polymer is usually 40 wt % or more, preferably 50 wt % or more, and more preferably 60 wt % or more. Specific examples of acrylate polymers include crosslinked acrylate polymers such as 2-ethylhexyl acrylate-methacrylic acid-acrylonitrile-ethylene glycol dimethacrylate copolymer, 2-ethylhexyl acrylate-methacrylic acid-methacrylonitrile-diethylene glycol dimethacrylate copolymer, 2-ethylhexyl acrylate-styrene-methacrylic acid-ethylene glycol dimethacrylate copolymer, butyl acrylate-acrylonitrile-diethylene glycol dimethacrylate copolymer, and butyl acrylate-acrylic acid-trimethylolpropane trimethacrylate copolymer; copolymers of ethylene and (meth)acrylic acid esters such as ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-ethyl methacrylate copolymer; and graft polymers in which a radically polymerizable monomer is grafted onto the copolymer of ethylene and (meth)acrylic acid ester. On the other hand, examples of the radically polymerizable monomer used in the graft polymers include methyl methacrylate, acrylonitrile, and methacrylic acid. Other examples of the dispersible binder include copolymers of ethylene and (meth)acrylic acid, such as ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer.

[0134] The fluoropolymer may include polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), and polyvinylidene fluoride copolymers such as PVDF-HFP, specifically polytetrafluoroethylene (PTFE), and more specifically polytetrafluoroethylene (PTFE).

[0135] In one embodiment of the present invention, when the electrode is a positive electrode, the positive electrode binder may include a fluorine-based copolymer. In a specific embodiment, the positive electrode may include PTFE among the fluorine-based copolymers, and more preferably, PTFE may be included in an amount of 60 wt% or more based on the total weight of the binder. Meanwhile, it goes without saying that the positive electrode binder may further include a fluorine-based copolymer other than PTFE, a styrene-based copolymer, a polyolefin-based copolymer, polyethylene oxide (PEO), an acrylate-based polymer, etc.

[0136] Meanwhile, in one embodiment of the present invention, when the electrode is a negative electrode, the negative electrode binder may include one or more of a diene-based polymer and a styrene-based polymer, which may be included in an amount of 60 wt% or more based on the total weight of the binder. In a specific embodiment, the negative electrode may include a styrene-butadiene block copolymer in an amount of 60 wt% or more based on the total weight of the binder. Meanwhile, it goes without saying that the negative electrode binder may further include a fluorine-based copolymer, a polyolefin-based copolymer, polyethylene oxide (PEO), an acrylate-based copolymer, etc.

[0137] Meanwhile, in the present invention, the binder resin for electrodes may contain a diene polymer and a crosslinked acrylate polymer, from the viewpoint that an active material layer having excellent adhesion to a current collector and excellent surface smoothness can be obtained, and an electrode for an electrochemical element having high capacitance and low internal resistance can be produced.

[0138] The shape of the electrode binder resin is not particularly limited, but a particulate form is preferred because it has good binding properties and can suppress a decrease in the capacitance of the produced electrode and deterioration due to repeated charge and discharge. Examples of particulate electrode binder resins include those in which dispersed binder particles are dispersed in water, such as latex, and powders obtained by drying this dispersion. Such particulate binders can preferably be contained in the negative electrode.

[0139] Meanwhile, in some cases, a filler, which is a component that suppresses expansion of the electrode active material layer, may be further added to the electrode active material layer. The filler is not particularly limited as long as it does not cause chemical changes in the battery and is a fibrous material, and examples of the filler that can be used include olefin polymers such as polyethylene and polypropylene; and fibrous materials such as glass fiber and carbon fiber.

[0140] <Primer layer> The primer layer includes a binder resin for the primer layer and a conductive material for the primer layer, and may further include a dispersant as necessary. The binder resin for the primer layer is not particularly limited as long as it is a known binder used in primer layers.

[0141] Examples of the binder resin for the primer layer include styrene butadiene rubber (SBR), butadiene rubber (BR), nitrile butadiene rubber (NBR), styrene butadiene styrene block polymer (SBS), styrene ethylene butadiene block polymer (SEB), styrene-(styrene butadiene)-styrene block polymer, natural rubber (NR), isoprene rubber (IR), ethylene-propylene diene terpolymer (EPDM), poly(ethylene-co-propylene-co-5-methylene-2-norbornene), polytetrafluoroethylene (PTFE), polyvinylidene fluoride, polyvinyl chloride, and polyvinylidene fluoride-hexafluoropropylene. fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethylmethacrylate, polyethylhexylacrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene, polypropylene, ethylene-vinyl acetate copolymer (polyethylene-co-vinyl acetate, polyethylene oxide, polypropylene oxide, polyarylate, cyanoethyl pullulan, cyanoethylpolyvinylalcohol, or two or more of these. Specifically, the binder may include styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR), polymethylmethacrylate, polyethylhexylacrylate, polybutylacrylate, or two or more of these.

[0142] Meanwhile, in one embodiment of the present invention, the binder resin for the primer layer may have a glass transition temperature of 45° C. or less so as to ensure stability of the primer layer over time.

[0143] In a specific embodiment, the binder resin for the primer layer may include styrene butadiene rubber (SBR) having a glass transition temperature (Tg) of -40°C to 45°C, nitrile butadiene rubber (NBR) having a glass transition temperature (Tg) of -40°C to 45°C, or a mixture thereof.

[0144] The conductive material for the primer layer is not particularly limited as long as it does not cause chemical changes in the battery and is conductive. Examples of the conductive material that can be used include graphite such as natural graphite and artificial graphite; carbon black-based carbon compounds such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber and metal fiber; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskey such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives. However, in order to uniformly mix the conductive material and improve conductivity, the conductive material may contain activated carbon, graphite, carbon black, or a mixture of two or more of these, and more specifically, activated carbon.

[0145] In one specific embodiment of the present invention, the conductive material for the primer layer has a specific surface area of ​​30 m 2 / g~1,400m 2 / g, and may include those having a spherical shape. In this case, the size of the primary particles of the conductive material having a spherical shape may be, for example, 10 nm to 100 nm, specifically 15 nm to 70 nm.

[0146] According to yet another embodiment of the present invention, the conductive material for the primer layer has a specific surface area of ​​10 m 2 / g~400m 2 The conductive material may have a tubular (tube-shaped) shape of 0.1 to 3 nm, specifically 0.3 to 1.5 nm, in cross section perpendicular to the longitudinal direction.

[0147] According to one embodiment of the present invention, the primer layer includes the above-mentioned composition and may have a thickness of 300 nm to 1.5 μm, specifically 700 nm to 1.3 μm, but is not limited thereto.

[0148] <Method for manufacturing electrode powder> According to one embodiment of the present invention, the electrode powder may be prepared by a method including the steps of: mixing an electrode active material and an electrode binder resin with a dispersion medium to prepare a slurry; and spray-drying the slurry.

[0149] First, the electrode active material and electrode binder, and optionally additional conductive materials and additives, are dispersed or dissolved in a dispersion medium (solvent for the negative electrode binder) to obtain a slurry in which the electrode active material and electrode binder, as well as the electrode conductive material and / or other additives, are dispersed or dissolved.

[0150] Water is most preferably used as the dispersion medium used to obtain the slurry, but organic solvents can also be used. Examples of organic solvents include alkyl alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol; alkyl ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, dioxane, and diglyme; amides such as diethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone (hereinafter also referred to as NMP), and dimethylimidazolidinone; and sulfur-based solvents such as dimethyl sulfoxide and sulfolane. Alcohols are preferred. The use of an organic solvent with a boiling point lower than that of water can increase the drying rate during fluidized bed granulation. Furthermore, since the dispersibility or solubility of the negative electrode binder may change, the viscosity and fluidity of the slurry can be adjusted depending on the amount or type of dispersion medium, thereby improving production efficiency.

[0151] The amount of the dispersion medium used when preparing the slurry can be an amount that results in a solids concentration in the slurry generally in the range of 1 to 50 wt %, or 5 to 50 wt %, or 10 to 30 wt %.

[0152] The method or order for dispersing or dissolving the electrode active material and electrode binder resin in the dispersion medium is not particularly limited, and examples include a method in which the electrode active material and electrode binder are added to the dispersion medium and mixed, or a method in which the electrode binder is dissolved or dispersed in the dispersion medium and then the electrode active material is added and mixed. If the slurry contains a conductive material and / or additives, these components may be added when the electrode active material is added. Examples of mixing means include mixing equipment such as a ball mill, sand mill, bead mill, pigment disperser, stone mill, ultrasonic disperser, homogenizer, and planetary mixer. Mixing may be carried out, for example, at room temperature to 80°C for 10 minutes to several hours.

[0153] Next, the slurry is spray-dried. Spray drying is a method in which a slurry is sprayed into hot air and dried. Atomizers are a typical example of a device used in spray drying. There are two types of atomizers: a rotating disk type and a pressure type. The rotating disk type is a method in which the slurry is taken into the approximate center of a disk rotating at high speed, and when the slurry is positioned outside the disk due to the centrifugal force of the disk, it is atomized and dried. The rotation speed of the disk depends on the size of the disk, but is usually 5,000 to 35,000 rpm, preferably 15,000 to 30,000 rpm. On the other hand, the pressure type is a method in which the slurry is pressurized and atomized from a nozzle and dried.

[0154] The temperature of the slurry to be sprayed is usually room temperature, but it can be heated to a temperature higher than room temperature. The temperature of the hot air during spray drying is usually 80°C to 250°C, preferably 100°C to 200°C. In the spray drying method, the method of inhaling the hot air is not particularly limited, and examples include a method in which the hot air and the spray direction flow sideways in parallel, a method in which the slurry is sprayed at the top of the drying tower and then descends together with the hot air, a method in which the sprayed droplets come into countercurrent contact with the hot air, and a method in which the sprayed droplets first flow parallel to the hot air and then fall by gravity in countercurrent contact.

[0155] Optionally, the product obtained by spray drying, i.e., the electrode powder, may be heat-treated to harden the surface thereof, and the heat-treatment temperature may be generally 80°C to 300°C.

[0156] The present invention provides a secondary battery in which an electrode assembly including the electrode obtained by the above-described method and a separator is housed in a battery case (cylindrical case, prismatic case, pouch, etc.) together with a lithium-containing non-aqueous electrolyte, and an energy storage device including the same as a unit battery, wherein at least one of the positive electrode and the negative electrode of the electrode may be the electrode obtained by the above-described method.

[0157] The separator may be a conventional porous polymer film, such as a polyolefin-based polymer film made of an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, or an ethylene / methacrylate copolymer, either alone or in a laminated state. Alternatively, an insulating thin film with high ion permeability and mechanical strength may be used. The separator may include a safety reinforced separator (SRS), in which a ceramic material is thinly coated on the surface of the separator. Alternatively, a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fiber or polyethylene terephthalate fiber, may be used, but is not limited to these.

[0158] The electrolytic solution contains a lithium salt as an electrolyte and an organic solvent for dissolving the lithium salt.

[0159] The lithium salt can be any one that is commonly used in electrolytes for secondary batteries without any particular limitation. For example, the anion of the lithium salt can be F - , Cl - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6- , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - , and (CF3CF2SO2)2N - One selected from the group consisting of:

[0160] The organic solvent contained in the electrolytic solution can be any commonly used organic solvent without any particular limitation, and typically, one or more selected from the group consisting of propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, dipropyl carbonate, dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, vinylene carbonate, sulfolane, γ-butyrolactone, propylene sulfide, and tetrahydrofuran can be used.

[0161] In particular, among the carbonate organic solvents, ethylene carbonate and propylene carbonate, which are cyclic carbonates, are preferred because they are high-viscosity organic solvents with high dielectric constants and thus easily dissociate lithium salts in the electrolyte. It is also preferred to mix such cyclic carbonates with linear carbonates having low viscosity and low dielectric constants, such as dimethyl carbonate and diethyl carbonate, in an appropriate ratio to prepare an electrolyte solution having high electrical conductivity.

[0162] Optionally, the electrolyte stored according to the present invention may further contain additives such as overcharge inhibitors that are typically included in electrolytes. In accordance with an embodiment of the present invention, a lithium secondary battery may be fabricated by forming an electrode assembly by disposing a separator between a positive electrode and a negative electrode, placing the electrode assembly in, for example, a pouch, a cylindrical battery case, or a prismatic battery case, and then injecting an electrolyte. Alternatively, the electrode assemblies may be stacked, impregnated with an electrolyte, and then placed in a battery case and sealed to form a lithium secondary battery.

[0163] At this time, the specific structures of the secondary battery and the energy storage device are well known and therefore will not be described in this specification. [Explanation of symbols]

[0164] 101 Current collector 102 Primer layer 103 Electrode powder 104 Electrode active material layer 111 Electrode active part 121 Dam 200 damage area 201 Laser irradiation area 301 Unwinder 302 Rewinder 400 Feeding Process 401 Feeder 500 Sheeting process 501 Sheeting Roll 600 Edge cleaning process 601 Laser

Claims

1. (S10) forming a primer layer having a predetermined width on at least one surface of the current collector; (S20) forming dams on both side surfaces of the primer layer in the width direction to prevent the electrode powder from flowing off; (S30) supplying electrode powder to the surface of the primer layer; (S40) compressing the electrode powder to form an electrode active material layer; A method for manufacturing a dry electrode, comprising:

2. The method for manufacturing a dry electrode according to claim 1 , wherein the dam protrudes from the surface of the current collector to a height greater than a height of the primer layer and is formed so as to be in close contact with a side surface of the primer layer without being spaced apart from the side surface.

3. (S50) The method for manufacturing a dry electrode according to claim 1, further comprising the step of removing the electrode active material layer existing outside the dam after performing the step (S40).

4. The method of claim 3, wherein the step (S50) is performed by laser irradiation or knife-type etching.

5. 2. The method for manufacturing a dry electrode according to claim 1, wherein the dam is made of a material that does not change the physical and chemical properties of the primer layer and the electrode powder even when the dam comes into contact with the primer layer and the electrode powder.

6. The method of claim 1 , wherein the dam comprises a polymeric material.

7. The method of claim 1 , wherein the step (S20) is performed by a printing method.

8. The method for manufacturing a dry electrode according to claim 1 , wherein the electrode powder contains an electrode active material and an electrode binder resin.

9. The method for producing a dry electrode according to claim 8 , wherein the electrode powder is produced by a spray drying method.

10. The method for producing a dry electrode according to claim 1 , wherein the primer layer contains a conductive material for a primer layer and a binder resin for a primer layer.

11. A dry electrode, a current collector and an electrode active portion formed on at least one surface of the current collector, the electrode active part includes a primer layer and an electrode active material layer formed on the primer layer, A dry electrode, wherein a dam is formed so as to cover the entire periphery of a side surface of the electrode active portion or at least a part of the entire periphery of the side surface.

12. The dry electrode according to claim 11 , wherein the dam is formed at the same height as or lower than the electrode active portion.

13. 12. The dry electrode according to claim 11, wherein the dam is made of a material that does not change the physical and chemical properties of the primer layer and the electrode powder even when the dam comes into contact with the primer layer and the electrode powder.

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