Method for manufacturing electrode structure, electrode structure manufactured thereby, and secondary battery comprising same

Abstract

The present disclosure provides a method for manufacturing an electrode structure, an electrode structure manufactured thereby, and a secondary battery comprising same. The method for manufacturing an electrode structure is a method for manufacturing an electrode structure for a secondary battery, and comprises: a step for preparing an electrode substrate; a step for processing the upper surface of the electrode substrate to form an adhesion reinforcement part for reinforcing adhesion with the electrode substrate; a step for evaluating adhesion characteristics of the electrode substrate on the basis of a surface state of the electrode substrate; and a step for bonding an electrode part onto the electrode substrate on the basis of the evaluation such that the electrode part is in direct contact with the adhesion reinforcement part, wherein the adhesion reinforcement part may comprise a plurality of needle-shaped nodules.

Description

Method for manufacturing an electrode structure, an electrode structure manufactured therefrom, and a secondary battery including the same

[0001] The present disclosure relates to a method for manufacturing an electrode structure, an electrode structure manufactured therefrom, and a secondary battery comprising the same.

[0002] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries capable of both charging and discharging. Low-capacity secondary batteries are used in small portable electronic devices such as smartphones, feature phones, laptop computers, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for motor drive systems and energy storage batteries in hybrid and electric vehicles. Such secondary batteries include an electrode assembly consisting of a positive electrode and a negative electrode, a case housing the assembly, and electrode terminals connected to the electrode assembly.

[0003] Generally, a dry electrode is manufactured by bonding an electrode film, formed into a film shape by applying pressure to an electrode substrate, an active material, a binder, and a conductive material, through a lamination process.

[0004] First, an active material, a conductive material, and a binder are mixed, and then an electrode film is formed in which the active material and the conductive material are bound together by a fiberized binder. Subsequently, a dry electrode is manufactured by pressing the electrode film onto an electrode substrate through a lamination process.

[0005] At this time, a primer layer is formed on the electrode film or electrode substrate to strengthen the adhesion between the electrode film and the electrode substrate, so that in a conventional dry electrode, a primer coating layer is disposed between the electrode substrate and the electrode film.

[0006] However, the primer coating layer is a component added to improve the adhesion between the electrode film and the electrode substrate, regardless of the function or operation of the dry electrode, and is a cause of reduced process costs and efficiency.

[0007] Accordingly, there is an increasing need for an electrode structure in which a dry electrode film and an electrode substrate are bonded without a separate primer layer.

[0008] The information described above disclosed in the background technology of this invention is intended only to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art.

[0009] The problem that the present disclosure aims to solve is to provide a method for manufacturing an electrode structure to solve the above-mentioned problems, an electrode structure manufactured therefrom, and a secondary battery including the same.

[0010] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems can be clearly understood by those skilled in the art from the description of the invention below.

[0011] According to some embodiments of the present disclosure for solving the above technical problem, a method for manufacturing an electrode structure comprises the steps of: preparing an electrode substrate; processing the upper surface of the electrode substrate to form an adhesive reinforcement portion that reinforces adhesion with the electrode substrate; evaluating the adhesive properties of the electrode substrate based on the surface condition of the electrode substrate; and, based on the evaluation, attaching an electrode portion to the electrode substrate so as to be in direct contact with the adhesive reinforcement portion, wherein the adhesive reinforcement portion may include a plurality of needle-shaped protrusions (nodules).

[0012] According to some embodiments of the present disclosure, the evaluation step may include: extracting first data from the upper surface of an electrode substrate through a sensor unit; processing the first data into second data through an L-Filter based on a cutoff length; calculating third data and fourth data based on the second data; and classifying the electrode substrate into a first electrode substrate or a second electrode substrate based on at least one of the third data and the fourth data.

[0013] According to some embodiments of the present disclosure, the first electrode substrate may include a plurality of needle-shaped irregularities, and the second electrode substrate may include a plurality of circular irregularities.

[0014] According to some embodiments of the present disclosure, the bonding step may include the step of bonding an electrode portion to a first electrode substrate when the electrode substrate is classified as a first electrode substrate based on an evaluation.

[0015] According to some embodiments of the present disclosure, the first data may include at least one of waveness, surface roughness, and form.

[0016] According to some embodiments of the present disclosure, the third data may include a minimum autocorrelation length (Sal), and the fourth data may include a texture-aspect ratio (Str).

[0017] According to some embodiments of the present disclosure, the classification step may include at least one of comparing third data with a predetermined first threshold interval or comparing fourth data with a predetermined second threshold interval.

[0018] According to some embodiments of the present disclosure, the forming step may include the step of forming a plurality of plating seeds on the upper surface of an electrode substrate, and the step of forming an adhesive reinforcing portion by depositing a plating metal material on the plating seeds to form a plurality of needle-shaped nodules having a plating height from the upper surface.

[0019] According to some embodiments of the present disclosure, the forming step may include forming a line-shaped mask pattern on the upper surface of an electrode substrate, partially removing the electrode substrate by an etching process using the mask pattern as an etching mask to form a plurality of trenches spaced apart at regular intervals having a line shape, and removing the mask pattern from the electrode substrate to form a line pattern having a plurality of trenches and a plurality of residual substrates.

[0020] According to some embodiments of the present disclosure, the method may further include the step of plating the upper surface of the electrode substrate or the step of etching the upper surface of the electrode substrate when the electrode substrate is classified as a second electrode substrate.

[0021] According to some embodiments of the present disclosure, the plating step may include the step of forming a plurality of plating seeds on the upper surface of an electrode substrate, and the step of depositing a plating metal material on the plating seeds to form a plurality of needle-shaped nodules having a plating height from the upper surface.

[0022] According to some embodiments of the present disclosure, the etching step may include forming a line-shaped mask pattern on the upper surface of an electrode substrate, partially removing the electrode substrate by an etching process using the mask pattern as an etching mask to form a plurality of trenches spaced apart at regular intervals having a line shape, and removing the mask pattern from the electrode substrate to form a line pattern having a plurality of trenches and a plurality of residual substrates.

[0023] According to some embodiments of the present disclosure, the first critical interval may be 1 μm to 2 μm.

[0024] According to some embodiments of the present disclosure, the second critical interval may be 0.2 to 1.

[0025] According to some embodiments of the present disclosure, the surface roughness (Rz) value of the upper surface of the electrode substrate may be 1 μm to 5 μm.

[0026] According to some embodiments of the present disclosure for solving the above technical problem, the electrode structure is an electrode structure for a secondary battery and comprises an electrode substrate composed of a conductive material, an electrode portion attached to the upper surface of the electrode substrate, and an adhesive reinforcing portion disposed on the electrode substrate to reinforce the adhesion between the electrode substrate and the electrode portion, wherein the adhesive reinforcing portion comprises a plurality of needle-shaped irregularities and the minimum self-correlation length (Sal) of the upper surface of the electrode substrate may be 1 μm to 2 μm.

[0027] According to some embodiments of the present disclosure, the texture-aspect ratio (Str) of the upper surface of the electrode substrate may be 0.2 to 1.

[0028] According to some embodiments of the present disclosure, the surface roughness value of the upper surface of the electrode substrate may be 1 μm to 5 μm.

[0029] According to some embodiments of the present disclosure for solving the above technical problem, a secondary battery comprises an electrode assembly comprising a first electrode including a first electrode structure, a second electrode including a second electrode structure, and a separator interposed between the first electrode and the second electrode, a case having an opening formed on one surface that accommodates the electrode assembly, and a cap assembly coupled to one surface of the case to seal the opening, wherein the first electrode structure comprises a first electrode substrate composed of a conductive material, a first electrode portion attached to the upper surface of the first electrode substrate, and a first adhesive reinforcing portion disposed on the first electrode substrate to reinforce the adhesion between the first electrode substrate and the first electrode portion, and the first adhesive reinforcing portion comprises a plurality of needle-shaped irregularities, and the minimum magnetic correlation length (Sal) of the upper surface of the electrode substrate may be 1 μm to 2 μm.

[0030] According to some embodiments of the present disclosure, the texture-aspect ratio (Str) of the upper surface of the electrode substrate may be 0.2 to 1.

[0031] According to some embodiments of the present disclosure, an electrode substrate can be classified into a first electrode substrate and a second electrode substrate based on at least one of data regarding the minimum magnetic correlation length (Sal) of the upper surface of the electrode substrate and data regarding the texture-aspect ratio (Str). By this configuration, the adhesion of the electrode substrate having needle-shaped irregularities can be quantitatively evaluated, thereby increasing the uniformity of the surface irregularity shape and thereby improving the adhesion between the electrode plate and the electrode substrate.

[0032] According to some embodiments of the present disclosure, the adhesive reinforcement may include a plurality of needle-shaped protrusions. In the case of needle-shaped protrusions, the contact area with the adhesive layer can be maximized to enhance the physical anchoring effect (Direct Anchoring). With this configuration, the adhesive reinforcement disposed on the electrode substrate reinforces the adhesion between the electrode and the electrode substrate, thereby enabling stable bonding of the electrode and the electrode substrate.

[0033] According to some embodiments of the present disclosure, when an electrode substrate is classified as a second electrode substrate based on evaluation, the upper surface of the electrode substrate may be plated and / or etched. By this configuration, surface irregularities may be converted to needle-like or uniformity may be improved through a re-etching or re-plating process. Specifically, long-period shapes may be removed and local height variations increased to form needle-like irregularities and maximize the contact area.

[0034] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below.

[0035] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0036] FIG. 1 is a flowchart illustrating a method for manufacturing an electrode structure according to one embodiment of the present disclosure.

[0037] FIG. 2 is a flowchart illustrating a method for forming an adhesive reinforcement portion by an electroplating process according to one embodiment of the present disclosure.

[0038] FIG. 3 is a flowchart illustrating a method for forming an adhesive reinforcement by an etching process according to one embodiment of the present disclosure.

[0039] FIG. 4 is a diagram illustrating a method for evaluating the adhesion characteristics of an electrode substrate according to one embodiment of the present disclosure.

[0040] FIG. 5 is a drawing showing an electrode structure according to one embodiment of the present disclosure.

[0041] FIG. 6 is a scanning electron microscope (SEM) image showing an electrode substrate having needle-shaped irregularities and circular irregularities formed thereon according to one embodiment of the present disclosure.

[0042] FIG. 7 is a schematic diagram showing a calendar device forming an electrode portion according to one embodiment of the present disclosure.

[0043] FIG. 8 is a schematic diagram showing a laminating apparatus for manufacturing an electrode structure according to one embodiment of the present disclosure.

[0044] FIG. 9 is a drawing showing an example of a secondary battery according to one embodiment of the present disclosure.

[0045] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe their invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0046] Additionally, as used herein, “comprise, include” and / or “comprising, including” specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups.

[0047] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0048] The statement that two subjects of comparison are 'identical' means that they are 'substantially identical.' Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.

[0049] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0050] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0051] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0052] Furthermore, where it is stated that one component is "connected," "coupled," or "connected" to another component, it should be understood that while said components may be directly connected or connected to each other, another component may be "interposed" between each component, or that each component may be "connected," "coupled," or "connected" through another component. Additionally, when it is stated that a part is electrically coupled with another part, this includes not only cases where they are directly connected but also cases where they are connected with another component in between.

[0053] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise. That is, "and / or" includes any combination or any combination of the enumerated items. "C to D" means C or more and D or less, unless specifically stated otherwise.

[0054] The terms used in this specification are intended to describe embodiments of the present invention and are not intended to limit the invention.

[0055] In this disclosure, the sizes and relative sizes of the regions depicted in the drawings may be exaggerated for clarity of description. That is, the sizes depicted in the drawings are for convenience of understanding only and are not limited thereto. Additionally, throughout the specification, the same reference numerals refer to the same components.

[0056] FIG. 1 is a flowchart illustrating a method for manufacturing an electrode structure according to one embodiment of the present disclosure.

[0057] Referring to FIG. 1, in order to form an electrode structure, an electrode substrate is first prepared (S100).

[0058] The electrode substrate can be appropriately selected as a conductive plate depending on the type of electrode active material of the electrode portion to be bonded. For example, a copper plate can be prepared as the electrode substrate bonded to the electrode portion having a negative electrode active material, and an aluminum plate can be prepared as the electrode substrate bonded to the electrode portion having a positive electrode active material.

[0059] Next, the upper surface of the prepared electrode substrate can be processed to form an adhesive reinforcement part that reinforces the adhesion with the electrode substrate (S200). The adhesive reinforcement part can be formed by various processes depending on its shape and structure.

[0060] According to one embodiment, the adhesive reinforcement may be formed by an electroplating process. According to another embodiment, the adhesive reinforcement may be formed by an etching process. This will be described later in FIGS. 2 and 3.

[0061] According to one embodiment, the electrode substrate may be cleaned before and after the formation of the adhesive reinforcement. More specifically, an acid cleaning process to remove impurities on the surface of the electrode substrate, such as resin components or natural oxide, a surface treatment process to form the adhesive reinforcement, and a water cleaning process to remove the acidic solution used for acid cleaning may be performed sequentially. As the acidic solution for the acid cleaning process, a hydrochloric acid solution, a sulfuric acid solution, a sulfuric acid-hydrogen peroxide solution, or a mixture of at least two of these may be used. The concentration and temperature of the acidic solution may be adjusted according to the characteristics of the production line. The aforementioned acid cleaning and water cleaning processes can improve the uniformity of the plating and etching processes performed through subsequent processes.

[0062] Next, the adhesion characteristics of the electrode substrate can be evaluated based on the surface condition of the electrode substrate (S300). The adhesion characteristics and evaluation method of the electrode substrate will be described later in FIG. 4.

[0063] According to one embodiment, if the adhesion characteristics evaluated based on the surface condition of the electrode substrate are poor, the upper surface of the electrode substrate may be re-plated. According to another embodiment, if the adhesion characteristics evaluated based on the surface condition of the electrode substrate are poor, the upper surface of the electrode substrate may be re-etched.

[0064] After that, based on the evaluation, the electrode portion can be bonded to the electrode substrate so as to be in direct contact with the adhesive reinforcement portion (S400). Here, the adhesive reinforcement portion may include a plurality of needle-shaped protrusions (Nodules).

[0065] The electrode portion can be formed by a repetitive calendering process on an electrode powder (EP) in which an electrode active material, a conductive material, and an active material are mixed. The film-shaped electrode portion can be formed through a calendering device, which is described later in FIG. 7. According to one embodiment, the electrode portion may correspond to a dry electrode film.

[0066] As a positive electrode active material, a compound capable of reversible intercalation and deintercalation of lithium (a lithated intercalation compound) may be used. Specifically, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.

[0067] The above composite oxide may be a lithium transition metal composite oxide, and specific examples include a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0068] As an example, a compound represented by any one of the following chemical formulas may be used. Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c About 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c About 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).

[0069] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L 1 is Mn, Al, or a combination thereof.

[0070] For example, the above-mentioned positive electrode active material may be a high-nickel positive electrode active material in which the nickel content relative to 100 mol% of the metal excluding lithium in the lithium transition metal composite oxide is 80 mol% or more, 85 mol% or more, 90 mol% or more, 91 mol% or more, or 94 mol% or more and 99 mol% or less. The high-nickel positive electrode active material can achieve high capacity and can be applied to high-capacity, high-density lithium secondary batteries.

[0071] A positive electrode for a lithium secondary battery may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer may include a positive electrode active material and may further include a binder and / or a conductive material.

[0072] For example, the above anode may further include an additive that can serve as a sacrificial anode.

[0073] The content of the positive active material is 90% to 99.5% by weight with respect to 100% by weight of the positive active material layer, and the content of the binder and the conductive material may each be 0.5% to 5% by weight with respect to 100% by weight of the positive active material layer.

[0074] The above binder serves to adhere the positive active material particles well to each other and also to adhere the positive active material well to the current collector. Representative examples of binders include, but are not limited to, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc.

[0075] The above conductive material is used to impart conductivity to the electrode, and any electronically conductive material that does not cause chemical changes can be used in the battery being constructed. Examples of conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube; metal-based materials in the form of metal powder or metal fibers containing copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0076] Al may be used as the current collector mentioned above, but is not limited thereto.

[0077] The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0078] A material capable of reversibly intercalating / deintercalating the above lithium ions may be a carbon-based negative electrode active material, such as crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0079] As the above lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn may be used.

[0080] As a material capable of doping and undoping the above lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used. The Si-based negative electrode active material may be silicon, a silicon-carbon composite, SiOx (0 < x < 2), a Si-Q alloy (wherein Q is selected from alkali metals, alkaline earth metals, group 13 elements, group 14 elements (excluding Si), group 15 elements, group 16 elements, transition metals, rare earth elements, and combinations thereof), or a combination thereof. The Sn-based negative electrode active material may be Sn, SnO2, a Sn-based alloy, or a combination thereof.

[0081] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, it may include a secondary particle (core) assembled from silicon primary particles and an amorphous carbon coating layer (shell) located on the surface of the secondary particle. The amorphous carbon may also be located between the silicon primary particles, so that, for example, the silicon primary particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0082] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0083] The above Si-based or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material.

[0084] A negative electrode for a lithium secondary battery comprises a current collector and a negative electrode active material layer located on the current collector. The negative electrode active material layer comprises a negative electrode active material and may further comprise a binder and / or a conductive material.

[0085] For example, the negative electrode active material layer may comprise 90% to 99% by weight of negative electrode active material, 0.5% to 5% by weight of binder, and 0% to 5% by weight of conductive material.

[0086] The above binder serves to effectively bond the negative electrode active material particles to each other and also to effectively bond the negative electrode active material to the current collector. As the binder, a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof may be used.

[0087] Examples of the above-mentioned non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or combinations thereof.

[0088] The above-mentioned water-based binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0089] When a water-based binder is used as the above-mentioned cathode binder, a cellulose-based compound capable of imparting viscosity may be further included. As this cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be mixed and used. Na, K, or Li may be used as the alkali metal.

[0090] The above dry binder is a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0091] The above conductive material is used to impart conductivity to the electrode, and any electronically conductive material that does not cause chemical changes can be used in the battery being constructed. Specific examples include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, carbon fiber, carbon nanofiber, carbon nanotube; metal-based materials in the form of metal powder or metal fibers including copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0092] As the above-mentioned cathode current collector, a material selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof may be used.

[0093] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0094] FIG. 2 is a flowchart illustrating a method for forming an adhesive reinforcement portion by an electroplating process according to one embodiment of the present disclosure.

[0095] Referring to FIG. 2, a plurality of plating seeds can first be formed on the upper surface of the electrode substrate (S210).

[0096] The plating seed is a part that functions as an anode during electroplating and is a region where the plating metal is deposited on the plating seed, and can be formed of the same material as the plating metal.

[0097] For example, a metal film identical to the plating metal can be patterned to form a plating seed in the shape of a metal pad on the upper surface of an electrode substrate in the shape of a matrix. Since plating is performed through cumulative deposition, the adhesive reinforcement can grow upward from the plating seed.

[0098] Therefore, when the plating interval of the plating seed is set, the spacing of the adhesive reinforcement formed by growing from the plating seed is also set based on the plating interval. Thus, by appropriately setting the plating interval of the plating seed, the spacing of the adhesive reinforcement formed in the subsequent plating process can be controlled.

[0099] In one embodiment, the plating seed may be composed of the same material as the electrode substrate. For example, if the electrode substrate contains copper, the plating seed may also be formed of copper to ensure uniformity of plating and prevent breakage caused by differences in physical properties between the electrode substrate and the adhesive reinforcement.

[0100] Next, a plating metal material can be deposited on a plating seed to form a plurality of needle-shaped irregularities having a constant plating height from the upper surface (S220).

[0101] For example, an electrode substrate having a plating seed is immersed in an electrolyte dissolved with plating metal ions, and an electric current is applied. Accordingly, plating ions electrochemically separated from the electrolyte are extracted onto the plating seed.

[0102] At this time, the thickness and shape of the deposited plating can be controlled by adjusting the applied voltage or current intensity, the type of electrolyte, the concentration of the electrolyte, and the transport ion concentration (pH).

[0103] According to one embodiment, protrusions of various shapes can be formed on the upper surface of an electrode substrate through a plating process. Accordingly, an adhesive reinforcement growing from a plating seed can be formed. For example, needle-shaped irregularities can be formed on the adhesive reinforcement through the plating process.

[0104] In particular, the height of the protrusions protruding from the electrode substrate can be controlled by adjusting the amount of plating metal deposited on the plating seed.

[0105] In one embodiment, the protrusion can be grown to have a plating height of 1 μm to 5 μm from the upper surface.

[0106] FIG. 3 is a flowchart illustrating a method for forming an adhesive reinforcement by an etching process according to one embodiment of the present disclosure.

[0107] Referring to FIG. 3, a line-shaped mask pattern can first be formed on the upper surface of the electrode substrate (S230). For example, a photoresist film can be formed on the electrode substrate, and then the mask pattern can be formed by an exposure process.

[0108] After loading an electrode substrate into a deposition chamber, a photoresist film is formed by depositing a photoresist at a uniform concentration, and the electrode substrate having the photoresist film is loaded into an exposure device and can be exposed using a reticle having a line-shaped exposure area.

[0109] Accordingly, the exposed area can be dissolved into a sol state, while the unexposed area can be maintained as a photoresist film. By removing the photoresist dissolved into a sol state through a development process, a photoresist pattern having a line shape can be obtained. The photoresist pattern can be used as a mask pattern in a subsequent etching process.

[0110] Next, a plurality of trenches having a line shape and spaced apart at regular intervals can be formed by partially removing the electrode substrate through an etching process using the mask pattern as an etching mask (S240). According to one embodiment, trenches can be formed by removing the electrode substrate exposed through the mask pattern to a set depth through an etching process using the mask pattern as an etching mask. For example, a plurality of trenches can be formed on the upper surface of the electrode substrate with a set depth and spaced apart at regular intervals along a direction perpendicular to the extension direction.

[0111] Next, a mask pattern can be removed from the electrode substrate to form a line pattern having a plurality of trenches and a plurality of residual substrates (S250).

[0112] The area of ​​the electrode substrate covered by the mask pattern and not removed during the etching process may be formed as a residual substrate located between adjacent trenches. The residual substrate is defined by trenches on both sides, and the trenches and the residual substrate may be arranged alternately. For example, the upper surface of the electrode substrate may be formed as a line pattern in which trenches having a set depth and the residual substrate are arranged alternately. According to one embodiment, the trenches may be formed to have a depth (D) of about 1 μm to 5 μm.

[0113] Wet etching and / or dry etching may be used to form needle-shaped irregularities on the surface of an electrode substrate. According to one embodiment, a trench or pattern formed on the substrate surface through wet etching may be selectively exposed to a chemical solution to form needle-shaped irregularities. For example, when the metal substrate is copper (Cu), solutions such as sulfuric acid (H2SO4), nitric acid (HNO3), and ferrous chloride (FeCl3) may be used, and when the metal substrate is aluminum (Al), etchants such as phosphoric acid (H3PO4), hydrochloric acid (HCl), and sodium hydroxide (NaOH) may be used. However, this is not limited thereto, and various chemical solutions may be selected to control the height and shape of the needle-shaped irregularities by adjusting the etching rate and anisotropy.

[0114] According to one embodiment, needle-shaped irregularities can be formed on the upper surface of an electrode substrate through dry etching. For example, needle-shaped irregularities can be formed through reactive ion etching (RIE), ion beam etching (IBE), plasma etching, etc. In the case of copper (Cu) and aluminum (Al) substrates, chlorine (Cl), a chlorine-based gas, can be used. 2) , boron trichloride (BCl 3) Alternatively, a combination of these gases can be used for dry etching, and needle-shaped irregularities can be formed by combining physical sputtering using argon (Ar) gas.

[0115] FIG. 4 is a diagram illustrating a method for evaluating the adhesion characteristics of an electrode substrate according to one embodiment of the present disclosure.

[0116] A method for evaluating the adhesion characteristics of an electrode substrate may be disclosed by extracting first data from the upper surface of the electrode substrate through a sensor unit (S310). According to one embodiment, a laser non-contact illuminance meter may be used for the sensor unit. A laser non-contact illuminance meter can measure the height and shape of a surface in a non-contact manner using laser light, and equipment such as the Keyence VK-X1100 may be used. However, it is not limited thereto, and various equipment for measuring the surface shape and characteristics of the electrode substrate may be used. For example, a white light interferometer, a 3D surface profiler, a contact surface roughness meter, an atomic force microscope, etc. may be used.

[0117] The extracted first data may include at least one of waveness, surface roughness, and form. The first data may be data representing surface characteristics of the electrode substrate measured on the upper surface of the electrode substrate. For example, waveness may represent changes in the height of the intermediate period of the surface, surface roughness may refer to changes in the height of the surface, and form may represent the overall surface profile of the upper surface of the electrode substrate.

[0118] After that, the first data can be processed into second data through an L-Filter based on the cutoff length (S320).

[0119] As described above, the first data is data representing surface characteristics extracted from the upper surface of the electrode gas, and the first data can be separated into short wavelength components and long wavelength components through an L-Filter based on a cutoff length. According to one embodiment, the second data may include short wavelength components, long wavelength components, or a combination thereof. Here, the L-Filter is a filter that separates specific components according to the frequency band of the first data, and can independently analyze and process each data by separating specific components according to frequency or spatial period. For example, the L-Filter may include a Gaussian filter. Specifically, the Gaussian filter is designed based on a Gaussian function and can separate the first data into long wavelength components and short wavelength components based on a cutoff length. For example, the Gaussian filter can remove long wavelength components or remove short wavelength components depending on a specific cutoff length. In one embodiment, the cutoff length may correspond to 0.025 mm. However, it is not limited to this, and an appropriate cutoff length may be set to separate long wavelength components and short wavelength components.

[0120] After that, the third data and the fourth data can be calculated based on the second data (S330).

[0121] Third data may include the minimum auto-correlated length (Sal). The minimum auto-correlated length is a value defined by ISO 25178 and may represent the distance at which the correlation between the surface height at a specific location and the surface height at another location within a certain distance decreases to 1 / e. The minimum auto-correlated length is one of the surface characteristics of the electrode substrate and may be an indicator that quantitatively represents how widely the surface texture is spatially distributed.

[0122] The fourth data may include the texture aspect ratio (Str). The texture aspect ratio is a value defined by ISO 25178 and is an indicator of the orientation of the surface texture, which can quantitatively indicate whether the height variation of the surface is uniform. For example, the texture aspect ratio may correspond to the value obtained by dividing the short wavelength component by the long wavelength component. The texture aspect ratio has a value between 0 and 1; a value closer to 1 indicates isotropy, while a value closer to 0 indicates anisotropy, meaning the texture is concentrated in a specific direction.

[0123] Next, the electrode substrate can be classified as a first electrode substrate or a second electrode substrate based on at least one of the third data and the fourth data (S340). According to one embodiment, the third data can be compared with a predetermined first threshold interval. Specifically, if it is within the predetermined first threshold interval, it can be classified as a first electrode substrate, and if it is outside the first threshold interval, it can be classified as a second electrode substrate. Here, the first electrode substrate may include a plurality of needle-shaped irregularities, and the second electrode substrate may include a plurality of circular irregularities. According to one embodiment, when the cutoff length is 0.025 mm, the first threshold interval may be 1 μm to 2 μm. However, it is not limited thereto, and as described above, an appropriate cutoff length may be set to separate long wavelength components and short wavelength components, and accordingly, the first threshold interval may be changed. For example, as the cutoff length is changed, the first threshold interval may be appropriately changed.

[0124] According to one embodiment, the fourth data can be compared with a predetermined second threshold interval. Specifically, if it is within the predetermined second threshold interval, it can be classified as a first electrode substrate, and if it is outside the second threshold interval, it can be classified as a second electrode substrate. Here, the first electrode substrate may include a plurality of needle-shaped irregularities, and the second electrode substrate may include a plurality of circular irregularities. According to one embodiment, when the cutoff length is 0.025 mm, the second threshold interval may be 0.2 to 1. However, it is not limited thereto, and as described above, an appropriate cutoff length may be set to separate long wavelength components and short wavelength components, and accordingly, the second threshold interval may be changed. For example, as the cutoff length is changed, the second threshold interval may be appropriately changed.

[0125] According to one embodiment, the surface roughness (Rz) value of the first electrode substrate may be 1 μm to 5 μm.

[0126] If the electrode substrate is classified as a first electrode substrate based on the above-described evaluation, the electrode portion can be attached to the first electrode substrate. By this configuration, the adhesive strength of the electrode substrate having needle-shaped irregularities is quantitatively evaluated, thereby increasing the uniformity of the surface irregularity shape and improving the adhesive strength between the electrode plate and the electrode substrate.

[0127] If the electrode substrate is classified as a second electrode substrate based on the above-described evaluation,

[0128] The upper surface of the electrode substrate can be plated and / or etched. With this configuration, surface irregularities can be converted to needle-like shapes or uniformity can be improved through a re-etching or re-plating process. Specifically, long-period shapes can be removed and local height variations increased to form needle-like irregularities and maximize the contact area. The plating process is identical to the electrolytic plating process described in FIG. 2, and the etching process is identical to the process described in FIG. 3; redundant descriptions are omitted. According to one embodiment, an electrode portion can be attached to the upper surface of the electrode substrate that has been plated and / or etched.

[0129] FIG. 5 is a drawing showing an electrode structure (500) according to one embodiment of the present disclosure.

[0130] Referring to FIG. 5, an electrode structure (500) according to one embodiment of the present disclosure may include an electrode substrate (100), an adhesive reinforcing portion (200) located on the electrode substrate, and an electrode portion (300) that adheres to the electrode substrate (100).

[0131] In one embodiment, the electrode substrate (100) may be composed of a material having high conductivity without causing chemical changes in the battery. For example, the electrode substrate (100) may be composed of stainless steel, aluminum, nickel, titanium, calcined carbon, copper, or a composite material surface-treated with carbon, nickel, titanium, silver, etc. on the surface of aluminum or stainless steel.

[0132] In one embodiment, an adhesive reinforcing member (200) is arranged on the upper surface of the electrode substrate (100) to reinforce the adhesive force between the electrode portion (300) and the electrode substrate (100). For example, the adhesive reinforcing member (200) may include a plurality of recessed portions (210) that expand the contact area with the electrode portion (300).

[0133] The surface of the electrode substrate (100) is recessed, and the contact area with the electrode portion (300) is increased by the side of the recess (210). Accordingly, the adhesion between the electrode substrate (100) and the electrode portion (300) can be reinforced by the frictional force generated by contact with the electrode portion (300) on the side of the recess (210).

[0134] For example, the recess (210) includes a plurality of recesses (211) aligned on the upper surface of the electrode substrate (100), and the surface of the electrode substrate (100) that is not relatively recessed forms a protrusion (212). Accordingly, the recess (210) is provided as an uneven pattern consisting of recesses (211) and protrusions (212).

[0135] The recessed portion (210) may include a plurality of needle-shaped nodules. The needle-shaped nodules may have various shapes having a protrusion height set from the upper surface of the electrode substrate (100) and strength such that they are not recessed by the electrode portion (300) during the laminating process.

[0136] According to one embodiment, the minimum magnetic correlation length (Sal) of the upper surface of the electrode substrate (100) including a plurality of needle-shaped irregularities may be 1 μm to 2 μm. According to one embodiment, the texture-aspect ratio (Str) of the upper surface of the electrode substrate (100) including a plurality of needle-shaped irregularities may be 0.2 to 1. According to one embodiment, the surface roughness (Rz) value of the upper surface of the electrode substrate (100) including a plurality of needle-shaped irregularities may be 1 μm to 5 μm. With this configuration, the adhesion strength between the electrode substrate (100) and the electrode portion (300) can be improved by the adhesive reinforcing portion (200).

[0137] According to one embodiment, fine solid particles can be sprayed or projected onto the surface of an electrode substrate (100) by sandblasting to form irregular irregularities on the upper surface. Due to the irregular collision between the upper surface of the electrode substrate (100) and the solid particles, the recesses (211a) are irregularly aligned, and the upper surface of the electrode substrate (100) where the recesses (211) are not placed is formed as a relatively uneven surface (212). Accordingly, the plurality of recesses (211) and the plurality of uneven surface (212) irregularly aligned on the upper surface of the electrode substrate (100) can increase the surface area of ​​the upper surface of the electrode substrate (100) and expand the contact area with the electrode portion (300).

[0138] FIG. 6 is a scanning electron microscope (SEM) image showing an electrode substrate having needle-shaped irregularities and circular irregularities formed thereon according to one embodiment of the present disclosure.

[0139] Referring to FIG. 6, circular irregularities may refer to a structure in which the surface irregularities are formed in a round shape, and needle-shaped irregularities may refer to a structure in which the surface irregularities are formed in a sharp and narrow shape. In the case of circular irregularities, the contact area is relatively small, so the physical bonding strength with the adhesive layer may be low, and if the texture is not uniform, the adhesion between the electrode part and the electrode substrate may be reduced.

[0140] Since circular and needle-shaped irregularities may have similar surface roughness (Rz) values, which represent the height difference between the highest and lowest parts of the surface, it is difficult to distinguish them based on these values ​​alone. In the present disclosure, the irregularity structures can be distinguished by additionally introducing the minimum autocorrelation length (Sal) and the texture-aspect ratio (Str) of the upper surface of the electrode substrate.

[0141] The adhesive reinforcement may include a plurality of needle-shaped protrusions. In the case of needle-shaped protrusions, the contact area with the adhesive layer can be maximized to enhance the physical anchoring effect (Direct Anchoring). With this configuration, the adhesion between the electrode and the electrode substrate can be stably bonded by reinforcing the adhesion between the electrode and the electrode substrate through the adhesive reinforcement disposed on the electrode substrate.

[0142] FIG. 7 is a schematic diagram showing a calendar device forming an electrode portion (300) according to one embodiment of the present disclosure.

[0143] Referring to FIG. 7, an electrode powder (EP) comprising one or more of an electrode active material, a binder resin, and a conductive material is formed into an electrode portion (300) having a constant thickness as it passes between pressure rollers (10). The pressure rollers (10) are composed of a plurality of pairs of rollers having different spacings, and are formed so that the thickness gradually decreases as they move from a pressure roller (10) with a wide spacing to a pressure roller (10) with a narrow spacing.

[0144] For example, the electrode portion (300) may have the shape of a sheet, a strip, or a film. According to one embodiment, the electrode portion (300) may be manufactured by a dry process in which a dispersion medium is not used to disperse electrode components such as an active material, a conductive material, and a binder. The electrode powder (EP) is crushed without a dispersion solvent and provided in a powder form, and is formed into the electrode portion (300) by high pressure applied from a pressure roller (10). For example, the electrode portion (300) may be provided as a dry electrode film.

[0145] The electrode portion (300) is inserted into a laminating device described later and supplied to an electrode substrate equipped with an adhesive reinforcing portion, and heat-pressed. Accordingly, the electrode portion (300) is pressed and adhered to the electrode substrate, and the adhesive force can be reinforced by the frictional force applied from the adhesive reinforcing portion. Accordingly, an electrode structure is formed in which the electrode portion (300) and the electrode substrate are stably adhered.

[0146] The electrode structure can be utilized as an electrode plate for various batteries that generate an electric current through chemical reactions. For example, the electrode structure can be utilized in primary batteries, secondary batteries, fuel cells, solar cells, and capacitors. Secondary batteries may include lithium-ion batteries in which lithium ions operate as ion conductors.

[0147] FIG. 8 is a schematic diagram showing a laminating apparatus for manufacturing an electrode structure according to one embodiment of the present disclosure.

[0148] Referring to FIG. 8, the electrode substrate (100) and the electrode portion (300) can be heat-pressed using a laminating device shown in FIG. 8.

[0149] First, the electrode substrate (100) and the dry electrode part (300) equipped with an adhesive reinforcement are passed between a pair of laminating rollers (20) to compress the adhesive reinforcement so that it penetrates into the electrode active material.

[0150] An electrode substrate (100) is supplied from a first supply unit and supplied between laminating rollers (20), and a dry electrode portion (300) is supplied from a pair of second supply units and can be pressed on the upper and lower surfaces of the electrode substrate (100), respectively.

[0151] An adhesive reinforcing portion as described above is formed on the upper and lower surfaces of the electrode substrate (100), and the electrode portion (300) can be pressed by a laminating roller (20).

[0152] At this time, since a separate adhesive layer is not disposed between the electrode portion (300) and the electrode substrate (100) according to one embodiment, the electrode portion (300) and the electrode substrate (100) can be compressed with a relatively smaller pressure.

[0153] FIG. 9 is a drawing showing an example of a secondary battery (1000) according to one embodiment of the present disclosure. A secondary battery according to one embodiment may include an electrode structure.

[0154] Referring to FIG. 9, a secondary battery (1000) according to one embodiment may include a first electrode including a first electrode structure and a second electrode including a second electrode structure. The first electrode structure and the second electrode structure may be identical to the electrode structures described above in FIGS. 1 to 8. For example, the first electrode structure may include a first electrode substrate composed of a conductive material, a first electrode portion attached to the upper surface of the first electrode substrate, and a first adhesive reinforcing portion disposed on the first electrode substrate, wherein the first adhesive reinforcing portion may include a plurality of needle-shaped protrusions. Duplicate descriptions below are omitted.

[0155] For the purpose of explaining the invention, the secondary battery (1000) in FIG. 9 is depicted in the form of a cylindrical battery, but the scope of the present disclosure is not limited thereto. The secondary battery (1000) is not limited to a cylindrical battery and includes batteries of any shape, such as prismatic batteries, pouch batteries, and coin batteries. Here, the battery may be a type of secondary battery.

[0156] The first electrode described above may correspond to a positive electrode (30), and the second electrode may correspond to a negative electrode (40). The secondary battery (1000) may include an electrode assembly (60) having a separator (50) interposed between the positive electrode (30) and the negative electrode (40), a case (70) in which the electrode assembly (60) is housed, and a sealing member (80) that seals the case (70). The positive electrode (30), the negative electrode (40), and the separator (50) may be impregnated with an electrolyte (not shown).

[0157] In one embodiment, the positive electrode (30) and the negative electrode (40) may include a coated portion, which is an area where an active material is applied to a current collector (or substrate) formed of a thin metal foil, and a non-coated portion, which is an area where an active material is not coated. The positive electrode (30) and the negative electrode (40) may be wound after interposing a separator (50), which is an insulator, between them. However, the present disclosure is not limited thereto, and the electrode assembly (60) described above may be formed in a structure in which a positive electrode (30) and a negative electrode (40), each made of a plurality of sheets, are alternately stacked with the separator (50) in between.

[0158] The electrode assembly (60) may be formed by winding or stacking a laminate of an anode (30), a separator (50), and a cathode (40) formed in a thin plate or film shape. If the electrode assembly (60) is a wound laminate, the winding axis may be parallel to the longitudinal direction of the case (70). Additionally, the electrode assembly (60) may be a stack type rather than a wound type, and the shape of the electrode assembly (60) is not limited in this disclosure. Furthermore, the electrode assembly (60) may be a Z-stack electrode assembly in which an anode (30) and a cathode (40) are inserted on both sides of a separator folded into a Z-stack. Additionally, one or more electrode assemblies (60) may be stacked so that their long sides are adjacent to each other and housed inside the case (70), and the number of electrode assemblies (60) is not limited in this disclosure.

[0159] The case (70) may be composed of materials commonly used in the industry to protect the internal components of the battery from external impact or fire. For example, depending on the purpose and function of the battery, it may be composed of a metal case including aluminum, aluminum alloy, nickel-plated steel or stainless steel, a plastic case including GFRP, or a combination thereof, depending on the choice of a person skilled in the art. Additionally, the case (70) may form the overall appearance of the battery (1000) by providing a space for accommodating the electrode assembly (60). For example, if the battery (1000) is a cylindrical battery, the case (70) may have a cylindrical shape, and the positive electrode (30), negative electrode (40), and separator (50) may be wound in a cylindrical shape. In some examples, the electrode assembly (60) may be accommodated in the case (70) together with the electrolyte.

[0160] In some examples, the electrode assembly (60) may be housed in a case (70) together with the electrolyte. Additionally, the electrode assembly (60) may be positioned such that a current collector is welded and connected to the electrode tabs of the positive electrode (30) and the negative electrode (40) exposed on both sides.

[0161] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

Claims

1. A method for manufacturing an electrode structure for a secondary battery Step of preparing an electrode substrate; A step of processing the upper surface of the electrode substrate to form an adhesive reinforcing portion that reinforces the adhesion with the electrode substrate; A step of evaluating the adhesion characteristics of the electrode substrate based on the surface condition of the electrode substrate; and Based on the above evaluation, the step of adhering an electrode portion to the electrode substrate so as to be in direct contact with the adhesive reinforcement portion. Includes, A method for manufacturing an electrode structure in which the adhesive reinforcement part comprises a plurality of needle-shaped nodules.

2. In Paragraph 1, The above evaluation step is, A step of extracting first data from the upper surface of the electrode substrate through a sensor unit; A step of processing the above first data into second data through an L-Filter based on a cutoff length; A step of calculating third data and fourth data based on the second data above; and A method for manufacturing an electrode structure, comprising the step of classifying the electrode substrate into a first electrode substrate or a second electrode substrate based on at least one of the third data and the fourth data.

3. In Paragraph 2, The first electrode substrate includes a plurality of needle-shaped protrusions, and A method for manufacturing an electrode structure in which the second electrode substrate comprises a plurality of circular irregularities.

4. In Paragraph 3, The above bonding step is, A method for manufacturing an electrode structure, comprising the step of adhering the electrode portion to the first electrode substrate when the electrode substrate is classified as the first electrode substrate based on the above evaluation.

5. In Paragraph 2, A method for manufacturing an electrode structure, wherein the first data comprises at least one of wave roughness, surface roughness, and form.

6. In Paragraph 2, The above third data includes the minimum autocorrelation length (Sal), and The above fourth data is a method for manufacturing an electrode structure including a texture-aspect ratio (Str).

7. In Paragraph 2, The above classification step is, A step of comparing the above third data with a predetermined first threshold interval, or A step of comparing the above-mentioned fourth data with a predetermined second threshold interval. A method for manufacturing an electrode structure comprising at least one of the following.

8. In Paragraph 1, The above forming step is, A step of forming a plurality of plating seeds on the upper surface of the electrode substrate; and A step of forming the adhesive reinforcing portion by precipitating a plating metal material on the plating seed to form a plurality of needle-shaped nodules having a plating height from the upper surface. A method for manufacturing an electrode structure comprising 9. In Paragraph 1, The above forming step is, A step of forming a line-shaped mask pattern on the upper surface of the electrode substrate; A step of partially removing the electrode substrate by an etching process using the above mask pattern as an etching mask to form a plurality of trenches having a line shape and spaced apart at regular intervals; and A step of removing the mask pattern from the electrode substrate to form a line pattern having the plurality of trenches and the plurality of residual substrates. A method for manufacturing an electrode structure comprising 10. In Paragraph 2, The above method is, When the above electrode substrate is classified as the above second electrode substrate, A step of plating the upper surface of the electrode substrate, or A method for manufacturing an electrode structure, further comprising the step of etching the upper surface of the electrode substrate.

11. In Paragraph 10, The above plating step is, A step of forming a plurality of plating seeds on the upper surface of the electrode substrate; and A method for manufacturing an electrode structure, comprising the step of depositing a plating metal material on the plating seed to form a plurality of needle-shaped nodules having a plating height from the upper surface.

12. In Paragraph 10, The above etching step is, A step of forming a line-shaped mask pattern on the upper surface of the electrode substrate; A step of partially removing the electrode substrate by an etching process using the above mask pattern as an etching mask to form a plurality of trenches having a line shape and spaced apart at regular intervals; and A step of removing the mask pattern from the electrode substrate to form a line pattern having the plurality of trenches and the plurality of residual substrates. A method for manufacturing an electrode structure comprising 13. In Paragraph 7, A method for manufacturing an electrode structure, wherein when the above cut-off length is 0.025 mm, the above first critical section is 1 μm to 2 μm.

14. In Paragraph 7, A method for manufacturing an electrode structure, wherein when the above cut-off length is 0.025 mm, the above second critical interval is 0.2 to 1.

15. In Paragraph 1, A method for manufacturing an electrode structure having a surface roughness (Rz) value of 1 μm to 5 μm on the upper surface of the electrode substrate.

16. As an electrode structure for a secondary battery, Electrode substrate composed of a conductive material; An electrode portion attached to the upper surface of the electrode substrate; and It includes an adhesive reinforcing member disposed on the electrode substrate to reinforce the adhesion between the electrode substrate and the electrode portion, and The above adhesive reinforcement includes a plurality of needle-shaped nodules. An electrode structure having a minimum self-correlation length (Sal) of the upper surface of the electrode substrate of 1 μm to 2 μm.

17. In Paragraph 16, An electrode structure having a texture-aspect ratio (Str) of the upper surface of the electrode substrate of 0.2 to 1.

18. In Paragraph 16, An electrode structure having a surface roughness (Rz) value of 1 μm to 5 μm on the upper surface of the electrode substrate.

19. An electrode assembly comprising a first electrode including a first electrode structure, a second electrode including a second electrode structure, and a separator interposed between the first electrode and the second electrode; A case that accommodates the above electrode assembly inside and has an opening formed on one side; It includes a cap assembly coupled to one surface of the above case to seal the opening, and The above first electrode structure is, A first electrode substrate composed of a conductive material; A first electrode portion attached to the upper surface of the first electrode substrate; and It includes a first adhesive reinforcing member disposed on the first electrode substrate to reinforce the adhesive force between the first electrode substrate and the first electrode portion, and The first adhesive reinforcement above includes a plurality of needle-shaped nodules, and A secondary battery having a minimum self-correlation length (Sal) of the upper surface of the electrode substrate of 1 μm to 2 μm.

20. In Paragraph 19, A secondary battery in which the texture-aspect ratio (Str) of the upper surface of the electrode substrate is 0.2 to 1.

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