Dry electrode structure and manufacturing method thereof

Abstract

A dry electrode structure and a method of manufacturing the same are provided. The electrode structure may include an electrode substrate including a conductive material, a dry electrode portion bonded to the electrode substrate, and an adhesion enhancing portion on the electrode substrate to enhance adhesion between the electrode substrate and the dry electrode portion.

Description

Technical Field

[0001] Aspects of embodiments of the present disclosure relate to a dry electrode structure and a method of manufacturing the same. Background Art

[0002] Generally, a dry electrode is manufactured by a lamination process of bonding an electrode substrate and an electrode film, and the electrode film is formed by extruding an active material, a binder, and a conductive material into a film shape.

[0003] First, an electrode film is formed by mixing an active material, a conductive material, and a binder, wherein the active material and the conductive material are bonded with a fibrillated binder. Then, the electrode film is extruded onto the electrode substrate by a lamination process to manufacture a dry electrode.

[0004] In this case, a primer layer is coated on the electrode film or the electrode substrate to enhance the bonding between the electrode film and the electrode substrate. Therefore, in a related art dry electrode, the primer layer coating is located between the electrode film and the electrode substrate.

[0005] However, the primer layer coating is a component added to improve the bonding between the electrode film and the electrode substrate, regardless of the function or operation of the dry electrode, and may result in additional process costs and reduced efficiency.

[0006] Therefore, it may be desirable to develop an electrode structure in which a dry electrode film and an electrode substrate are bonded together without a separate primer layer coating.

[0007] The above information disclosed in this background art section is to enhance the understanding of the background art of the present disclosure, and thus may include information that does not constitute related (or prior) art. Summary of the Invention

[0008] Aspects of embodiments of the present disclosure relate to a dry electrode structure for a secondary cell and a method of manufacturing the same.

[0009] Embodiments of the present disclosure provide an electrode structure in which an electrode substrate and a dry electrode are stably bonded to each other without an additional primer layer coating.

[0010] In addition, embodiments of the present disclosure provide a method of manufacturing the above electrode structure.

[0011] However, the present disclosure is not limited to the above, and those skilled in the art will clearly understand other aspects not mentioned herein from the following description of the present disclosure.

[0012] An electrode structure according to one or more embodiments of the present disclosure may include an electrode substrate including a conductive material, a dry electrode portion bonded to the electrode substrate, and a bonding enhancement portion on the electrode substrate that enhances the bonding force between the electrode substrate and the dry electrode portion.

[0013] The bonding enhancement portion may include a recessed portion that is recessed downward from the upper surface of the electrode substrate to increase the contact area for contacting the dry electrode portion.

[0014] The recessed portion may include a recessed portion provided in the upper surface of the electrode substrate and a protruding portion that protrudes compared to the recessed portion.

[0015] The recessed portion may include a groove that is recessed downward from the upper surface of the electrode substrate and a remaining base material portion that alternates with the groove.

[0016] The recessed portion may have a depth of about 1 μm to about 5 μm and a width of about 1 μm to about 5 μm.

[0017] The bonding enhancement portion may include a protrusion that protrudes upward from the upper surface of the electrode substrate.

[0018] The protrusion may include a serrated shape, a column shape, a hemispherical shape, or a dendritic shape including branches branching from the column shape.

[0019] The protrusion may include an electroplated portion that includes the same material as the electrode substrate.

[0020] The protrusion may have a height of about 1 μm to about 5 μm, and there is a gap of about 1 μm to about 5 μm between adjacent protrusions in the protrusion.

[0021] The dry electrode portion may include a dry electrode film produced by a dry electrode process without a dispersant for dispersing an active material, a conductive material, or a binder.

[0022] The dry electrode portion may include a negative electrode active material, wherein the electrode substrate and the bonding enhancement portion include a copper thin film, a nickel thin film, a stainless steel thin film, a titanium thin film, a nickel foam, a copper foam, a polymer substrate coated with a conductive metal, or a combination thereof.

[0023] The dry electrode portion may include a positive electrode active material, wherein the electrode substrate and the bonding enhancement portion include aluminum.

[0024] A method of manufacturing an electrode structure according to one or more embodiments of the present disclosure may include preparing an electrode substrate, forming a bonding enhancement portion for enhancing the bonding force of the electrode substrate by treating the upper surface of the electrode substrate, and bonding the dry electrode portion to the electrode substrate so as to be in direct contact with the bonding enhancement portion.

[0025] The formation of the adhesion enhancing portion may include forming plating seeds on the upper surface of the electrode substrate, and forming protrusions having a plating height from the upper surface by depositing a plating metal material on the plating seeds via a plating process.

[0026] Adjacent plating seeds in the plating seeds may have a gap of about 1 μm to about 5 μm.

[0027] The plating height may be about 1 μm to about 5 μm.

[0028] Forming the adhesion enhancing portion may include forming a mask pattern on the upper surface of the electrode substrate, forming grooves having a line shape and spaced apart from each other by a gap by partially removing the electrode substrate via an etching process using the mask pattern as an etching mask, and forming a line pattern including the grooves and the remaining matrix material portion by removing the mask pattern from the electrode substrate.

[0029] Forming the mask pattern may include forming a photoresist film on the electrode substrate, performing an exposure process on the photoresist film to have a line shape, and developing the photoresist film.

[0030] The method may further include forming a dry electrode portion by repeatedly performing a calendaring process on electrode powder in which an electrode active material, a conductive material, and a binder are mixed.

[0031] Bonding the dry electrode portion to the electrode substrate may include a lamination process of thermally pressing the electrode substrate and the dry electrode portion by feeding the electrode substrate and the dry electrode portion between a pair of laminating rollers.

[0032] According to an embodiment of the present disclosure, even if an additional adhesive layer such as an undercoat layer is omitted, the electrode portion and the electrode substrate can be firmly bonded by enhancing the adhesive force between the electrode portion and the electrode substrate via the adhesion enhancing portion located on the electrode substrate. Accordingly, stability can be improved while reducing the undercoat layer coating cost in the manufacturing process of the dry electrode structure.

[0033] The dry electrode substrate may correspond to a current collector of a Li secondary battery cell, and the dry electrode portion may include an active material of the Li secondary battery cell.

[0034] However, aspects of the present disclosure are not limited to those described above, and other aspects not mentioned will be clearly understood by those skilled in the art from the detailed description described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The following drawings attached to this specification illustrate embodiments of the present disclosure and further describe aspects of the present disclosure together with the detailed description of the present disclosure. Therefore, the present disclosure should not be construed as limited to the drawings:

[0036] Figure 1 Shows a dry electrode structure for a secondary battery cell according to an embodiment of the present disclosure;

[0037] Figure 2 Shows Figure 1 one or more other embodiments of the recessed portion shown in;

[0038] Figure 3 Shows a bond enhancing portion according to one or more other embodiments of the present disclosure;

[0039] Figures 4 to 6 Shows according to one or more other embodiments of the present disclosure Figure 3 the shape of the protrusion shown in;

[0040] Figure 7 Schematically shows a calendering device for forming an electrode layer as shown in Figure 1 shown;

[0041] Figure 8 Shows a flowchart showing a method of manufacturing Figure 1 the electrode structure shown;

[0042] Figure 9 Shows a flowchart showing a method of forming a bond enhancing portion by an electrolytic plating process;

[0043] Figure 10 Shows a scanning electron microscope (SEM) image showing an electrode substrate in which protrusions are formed by Figure 9 the electrolytic plating process shown;

[0044] Figure 11 Shows a flowchart showing a method of forming a bond enhancing portion by an etching process;

[0045] Figure 12 Schematically shows a lamination device for manufacturing Figure 1 the electrode structure shown; and

[0046] Figure 13 Shows an SEM image showing the state in which an electrode portion is pressed onto Figure 10 the electrode substrate shown by a lamination process. Detailed Description

[0047] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Terms or words used in this specification and claims should not be construed as limited to the ordinary or dictionary meanings, and should be interpreted based on the principle that the inventor can be his / her own lexicographer, thus appropriately defining the concept of the terms to best explain his / her invention in a way consistent with the technical concept of the present disclosure.

[0048] The embodiments described in this specification and the configurations shown in the accompanying drawings are only some embodiments of the present disclosure and do not represent all the technical ideas, aspects, and features of the present disclosure. Therefore, it should be understood that various equivalents and modifications may be available to replace or modify the embodiments described herein at the time of filing this application.

[0049] It should be understood that when an element or layer is referred to as "on another element or layer", "connected to" or "coupled to" another element or layer, it can be directly on another element or layer, connected to or coupled to another element or layer, or there may also be one or more intermediate elements or layers. When an element or layer is referred to as "directly on another element or layer", "directly connected to" or "directly coupled to" another element or layer, there are no intermediate elements or layers. For example, when a first element is described as "coupled" or "connected" to a second element, the first element can be directly coupled or connected to the second element, or the first element can be indirectly coupled or connected to the second element via one or more intermediate elements.

[0050] In the accompanying drawings, for clarity of illustration, the dimensions of various elements, layers, etc. may be exaggerated. Like reference numerals denote like elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Further, when describing embodiments of the present disclosure, the use of "may" refers to "one or more embodiments of the present disclosure". Expressions such as "at least one of" and "any one of", when following a list of elements, modify the entire list of elements and not individual elements of the list. When phrases such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group consisting of A, B, and C", or "at least one selected from among A, B, and C" are used to specify a list of elements A, B, and C, the phrase can refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the terms "use", "using", and "used" may be considered synonymous with the terms "utilize", "utilizing", and "utilized", respectively. As used herein, the terms "substantially", "about", and similar terms are used as approximate terms and not terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by a person of ordinary skill in the art

[0051] It should be understood that although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Thus, a first element, component, region, layer, or portion discussed below may be referred to as a second element, component, region, layer, or portion without departing from the teachings of the exemplary embodiments

[0052] For ease of description, this document may use spatially relative terms, such as "beneath", "below", "lower", "above", "upper", etc., to describe the relationship of one element or feature to another element or feature shown in the figures. It should be understood that, in addition to the orientation described in the figures, spatially relative terms are intended to cover different orientations of the device during use or operation. For example, if the device in the figure is flipped, an element described as "below" or "beneath" other elements or features will be oriented "above" or "over" the other elements or features. Thus, the term "below" can cover both upward and downward orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0053] The terms used herein are for the purpose of describing embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, the singular forms "a" and "an" are also intended to include the plural forms, unless the context clearly indicates otherwise. It will also be understood that the terms "includes", "including", "comprises" and / or "comprising", when used in this specification, specify the presence of the stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0054] In addition, any numerical range disclosed and / or recited herein is intended to include all sub-ranges of the same numerical precision contained within the stated range. For example, the range "1.0 to 10.0" is intended to include all sub-ranges between the stated minimum value 1.0 (inclusive) and the stated maximum value 10.0 (inclusive), i.e., having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Thus, the applicant reserves the right to modify this specification (including the claims) to expressly recite any sub-ranges contained within the ranges expressly recited herein. All such ranges are intended to be inherently described in this specification such that a modification that expressly recites any such sub-range will be compliant.

[0055] Referring to two compared elements, features, etc. as "the same" may mean that they are "substantially the same". Thus, the phrase "substantially the same" may include cases that are considered to have a low deviation in the art, e.g., a deviation of 5% or less. Further, when a certain parameter is said to be uniform in a given region, this may mean that it is uniform in terms of the average value.

[0056] Throughout the specification, unless otherwise specified, each element may be singular or plural.

[0057] Disposing any element "above (or below)" or "on (or under)" another element may mean that the any element may be in contact with the upper (or lower) surface of the element, and the other element is also inserted between the element and any element located on (or under) the element.

[0058] Further, it will be understood that when a component is said to be "linked", "coupled", or "connected" to another component, the elements may be directly "coupled", "linked", or "connected" to each other, or another component may be "inserted" between the components.

[0059] Throughout the specification, unless otherwise specified, when stating "A and / or B", it means A, B, or A and B. That is, "and / or" includes any or all combinations of the recited multiple items. Unless otherwise specified, when stating "C to D", it means C or greater and D or less.

[0060] Figure 1 A dry electrode structure for a secondary cell according to an embodiment of the present disclosure is shown.

[0061] Reference Figure 1 , a dry electrode structure 500 according to an embodiment of the present disclosure may include an electrode substrate 100, an adhesion enhancement portion 200 located on the electrode substrate 100, and an electrode portion 300 adhered to the electrode 100.

[0062] In some embodiments, the electrode substrate 100 may include a material that does not cause significant chemical changes in the cell and has high electrical conductivity.

[0063] For example, the electrode substrate 100 may include stainless steel, aluminum (Al), nickel (Ni), titanium (Ti), calcined carbon, copper (Cu), or a composite material in which Al or stainless steel is surface-treated with carbon (C), Ni, Ti, silver (Ag), etc. It will be understood that the electrode substrate 100 may be provided in various ways depending on the polarity of the dry electrode structure 500.

[0064] For example, the thickness of the electrode substrate 100 can range from about 10 μm to about 50 μm (e.g., from about 10 μm to about 20 μm). However, this is illustrative, and depending on the process characteristics of the electrode structure 500 or the characteristics of the battery cell or energy storage device manufactured using the electrode structure 500, the electrode substrate 100 can be provided in various thicknesses.

[0065] In some embodiments, the adhesion enhancement portion 200 is disposed on the upper surface of the electrode substrate 100 to enhance the adhesion between the electrode portion 300 and the electrode substrate 100.

[0066] For example, the adhesion enhancement portion 200 can include a plurality of recessed portions 210 that are recessed downward from the upper surface of the electrode substrate 100 to increase the contact area of the electrode substrate 100 with the electrode portion 300.

[0067] The surface of the electrode substrate 100 is recessed such that the contact area with the electrode portion 300 is increased by the side surfaces of the recessed portions 210. The frictional force generated from the side surfaces of the recessed portions 210 by contact with the electrode portion 300 can enhance the adhesion between the electrode substrate 100 and the electrode portion 300.

[0068] For example, the recessed portion 210 includes a plurality of recessed parts 211 disposed in the upper surface of the electrode substrate 100 and a raised portion 212 formed by the relatively non-recessed surface portion of the electrode substrate 100. The recessed portion 210 is provided as a texture pattern including the recessed parts 211 and the raised portion 212.

[0069] Irregular textures can be formed on the upper surface by spraying or projecting fine solid particles onto the surface of the electrode substrate 100 via sandblasting. In response to the irregular collision of the solid particles with the upper surface of the electrode substrate 100, the recessed parts 211 are irregularly arranged, and the raised portion 212 is relatively formed by the surface portion of the electrode substrate 100 where no recessed part 211 is located. The recessed parts 211 and the raised portion 212 irregularly arranged in the upper surface of the electrode substrate 100 can increase the surface area of the upper surface of the electrode substrate 100 and can increase the contact area contacting the electrode portion 300.

[0070] Each of the recessed parts 211 can have a depth of about 1 μm to about 5 μm. If the depth of the recessed part 211 is less than about 1 μm, the surface area increased by the recessed part 211 may not be significant / enough, and it may be difficult to obtain an adhesion enhancement effect. If the depth of the recessed part 211 is greater than about 5 μm, the electrode substrate 100 can have reduced flexibility and increased brittleness, and can increase the breakage rate of the electrode structure 500 in subsequent processes.

[0071] Figure 2 shows Figure 1 one or more other embodiments of the recessed portion shown.

[0072] Referring Figure 2 , the recessed portion 210 may include a line pattern 215, the line pattern 215 including a plurality of line-shaped grooves 215a recessed downward from the upper surface of the electrode substrate 100, and a plurality of remaining substrate material portions 215b that alternate with the grooves 215a and are not recessed to be defined by the grooves 215a.

[0073] If the line-shaped grooves 215a are formed in the upper surface of the electrode substrate 100 in one direction (e.g., a predetermined direction) or are defined by the upper surface of the electrode substrate 100 in one direction (e.g., a predetermined direction), a part of the upper surface of the electrode substrate 100 defined by a pair of adjacent grooves 215a remains (e.g., in the form of a line in the same direction as the initial electrode substrate). The grooves 215a and the remaining substrate material portions 215b are alternately positioned to form the entire line pattern 215.

[0074] In one or more embodiments, each of the grooves 215a may have a depth D of about 1 μm to about 5 μm, and the gap G (e.g., the width of one of the grooves 215a) between adjacent remaining substrate material portions 215b may range from about 1 μm to about 5 μm. In one or more embodiments, the width of each of the remaining substrate material portions 215b may be set to range from about 1 μm to about 5 μm.

[0075] For example, the line pattern 215 may be formed by performing dry etching or wet etching on the electrode substrate.

[0076] The adhesion enhancement portion 200 can increase the contact area not only by the recess that is recessed downward from the upper surface of the electrode substrate 100, but also by the protrusion that protrudes upward.

[0077] A plurality of protrusions 250 may be provided that protrude upward to increase the contact area of the contact electrode portion 300.

[0078] Figure 3 Shows an adhesion enhancement portion according to one or more other embodiments of the present disclosure. Figures 4 to 6 shows Figure 3 the shape of the protrusion shown in

[0079] Referring Figure 3 , Figure 4 , Figure 5 and Figure 6 , the protrusions 250 may protrude upward from the upper surface of the electrode substrate 100 to increase the contact area of the contact electrode portion 300.

[0080] The protrusion 250 may have various shapes formed by different processes, as long as the protrusion 250 has a protrusion height H (e.g., a predetermined protrusion height) from the upper surface of the electrode substrate 100 and is strong enough not to be recessed by the electrode portion 300 during the lamination process.

[0081] For example, the protrusion 250 may include a column-shaped protrusion 251 having a column shape formed by deposition, patterning, or electroplating, may include a serrated-shaped protrusion 252 having a serrated shape, may include a hemispherical protrusion 253 having a hemispherical shape, or may include a dendritic-shaped protrusion 254 having a branched shape. However, the above are merely examples, and the protrusion 250 may be provided in various shapes as long as the stability of the bond between the electrode portion 300 and the electrode substrate 100 can be increased.

[0082] The protrusion 250 may be implemented as an electroplated portion formed by electroplating. The electroplated portion includes the same material as the electrode substrate 100 for the uniformity of plating.

[0083] If the electrode portion 300 includes a negative electrode active material and if the electrode substrate 100 includes copper (Cu), then the protrusion 250 may include Cu. If the electrode portion 300 includes a positive electrode active material and if the electrode substrate 100 includes aluminum (Al), then the protrusion 250 may include Al.

[0084] In one or more embodiments, the protrusion 250 is configured to appropriately penetrate the electrode portion 300 during the lamination process such that the side surface of the protrusion 250 can be in sufficient contact with the electrode portion 300.

[0085] The height H and the gap G of each protrusion 250 are respectively set in the range of about 1 μm to about 5 μm. If the height of the protrusion 250 is lower than about 1 μm, the contact area between the protrusion 250 and the electrode portion 300 is insufficient, and effective frictional force may not be appropriately generated. If the height of the protrusion 250 is higher than about 5 μm, the protrusion 250 may be susceptible to buckling and may bend before penetrating the electrode portion 300. In this case, the protrusion 250 may not have a sufficient contact area for contacting the electrode portion 300.

[0086] If the gap of the protrusions 250 (e.g., the gap between the protrusions) is less than about 1 μm, the contact area where the electrode substrate 100 contacts the electrode portion 300 and between the protrusions 250 may be insufficient, and the electrode portion 300 may not be properly pressed onto the electrode substrate 100 during the lamination process. If the gap of the protrusions 250 is greater than about 5 μm, the gap between adjacent protrusions 250 is too wide, and the protrusions 250 may slide and may bend when assembled into the electrode portion 300.

[0087] The height H and the gap of each protrusion 250 are respectively set in the range of about 1 μm to about 5 μm.

[0088] Column-shaped protrusions 251 having a uniform height H and the same gap G can be arranged in a matrix form on the upper surface of the electrode substrate 100. The electrode portion 300 contacts the column-shaped protrusions 251, the electrode portion 300 can be fixed by frictional force, and the electrode portion 300 can be pressed into the portion between the column-shaped protrusions 251 on the upper surface of the electrode substrate 100 by a compressive force. Even without a separate adhesive layer, the electrode portion 300 can be firmly bonded to the electrode substrate 100 by the compressive force and the frictional force.

[0089] Compared with the column-shaped protrusions 251, the sawtooth-shaped protrusions 252 can improve the penetration characteristics into the electrode portion 300. In one or more embodiments, the hemispherical protrusions 253 can be configured to substantially eliminate the horizontal component of the frictional force, such that only the vertical component pointing to the electrode substrate 100 can effectively act. Compared with the column-shaped protrusions 251, the sliding caused by the shear force between the electrode substrate 100 and the electrode portion 300 can be reduced or minimized, and the bonding stability can be improved.

[0090] Each dendritic protrusion 254 can include a main body 254a having a configuration substantially the same as that of each column-shaped protrusion 251, and branches 254b branching upward and / or laterally from the main body 254a. Each dendritic protrusion 254 is implemented as a composite protrusion combining the column-shaped protrusion 251 and the hemispherical protrusion 253.

[0091] The main body 254a can be provided as a base for supporting the branches 254b, and the branches 254b can extend in a hemispherical shape from the upper part of the main body 254a to increase the surface area.

[0092] In the lower part of the main body 254a, the side surface of the main body 254a contacts the electrode portion 300. In the upper part of the main body 254a, the branches 254b contact the electrode portion 300. The surface area of the dendritic protrusion 254 can be further increased to be greater than the surface area of the column-shaped protrusion 251.

[0093] It is disclosed that the gap between adjacent branches 254b is set to the gap between adjacent tree-branch-shaped protrusions 254, but this is merely illustrative. As with the column-shaped protrusions 251, the gap between adjacent main bodies 254a can be set to the gap between the tree-branch-shaped protrusions 254.

[0094] In one or more embodiments, the branches 254b of the tree-branch-shaped protrusions 254 can have a hemispherical shape, but the branches 254b can be configured to have a serrated shape or can be implemented as a beam-shaped frame. The shape of the branches 254b can be appropriately modified according to various aspects of penetration into the bonded electrode portion 300 and according to the structure that generates frictional force together with the electrode portion 300.

[0095] In some embodiments, the electrode portion 300 includes a dry electrode layer that includes an active material, a conductive material, and a binder.

[0096] Figure 7 Schematically shows a calendering device for forming an electrode layer as Figure 1 shown.

[0097] Referring to Figure 7 , electrode powder EP including at least one of an electrode active material, a binder resin, and / or a conductive material forms an electrode portion 300 having a thickness (e.g., a predetermined thickness) when passing between the calender rolls 10. The calender rolls 10 are implemented as a plurality of roll pairs having different gaps and are configured such that the thickness of the electrode portion gradually decreases when moving from a pair of calender rolls 10 having a wider gap to another pair of calender rolls 10 having a narrower gap.

[0098] For example, the electrode portion 300 can also have the shape of a sheet, a strip, or a film.

[0099] For example, the electrode portion 300 is implemented as a dry electrode layer manufactured by a dry process in which a dispersant for dispersing electrode components (such as an active material, a conductive material, and / or a binder) is not used. The electrode powder EP can be ground without a dispersion solvent to be provided as a powder and can be formed into the electrode portion 300 under high pressure applied by the calender rolls 10. For example, the electrode portion 300 can be provided as a dry electrode film.

[0100] The electrode portion 300 can be inserted into the laminating device described below, and the electrode portion 300 is supplied from the laminating device to the electrode substrate 100 including the bonding enhancement portion 200 to be thermally pressed thereto. The electrode portion 300 can be extruded and bonded to the electrode substrate 100, and the bonding force can be enhanced by the frictional force applied from the bonding enhancement portion 200, and an electrode structure 500 in which the electrode portion 300 and the electrode substrate 100 are firmly bonded is formed.

[0101] The electrode structure 500 can be used as an electrode plate for various battery cells that generate an electric current through a chemical reaction. For example, the electrode structure 500 can be used in primary battery cells, secondary battery cells, fuel cells, photovoltaic cells, capacitors, etc. The secondary battery cell can include a lithium (Li)-ion battery cell, in which Li ions act as ion conductors.

[0102] For example, in the related art, an undercoat layer including a binder component is formed on the electrode substrate 100 or the electrode portion 300 through a separate process to bond the electrode portion 300 manufactured through a dry process to the electrode substrate 100. However, in the present disclosure, the bonding force between the electrode portion 300 and the electrode substrate 100 can be enhanced by the bonding enhancement portion 200 located on the electrode substrate 100, and even if the undercoat layer is omitted, the electrode portion 300 and the electrode substrate 100 can be allowed to firmly engage, and the cost of coating the undercoat layer in the manufacturing process of the dry electrode structure 500 can be reduced.

[0103] Figure 8 Shows a flowchart showing a method of manufacturing Figure 1 the electrode structure shown in

[0104] Hereinafter, a method of manufacturing Figures 1 to 7 the electrode structure shown in Figures 1 to 7 will be disclosed. The same reference numerals will be used to denote the same components as in

[0105] Referring to Figure 8 , first, in operation S100, an electrode substrate is prepared to form Figure 1 the electrode structure 500 shown in

[0106] The electrode substrate 100 can be appropriately selected as a conductive electrode plate according to the type of the electrode active material of the electrode portion 300 to be bonded. A Cu electrode plate can be prepared for the electrode substrate 100 bonded to the electrode portion 300 including a negative electrode active material, and an Al electrode plate can be prepared for the electrode substrate 100 bonded to the electrode portion 300 including a positive electrode active material.

[0107] Subsequently, in operation S200, the prepared electrode substrate 100 can be processed to form a bonding enhancement portion 200 on its upper surface. For example, the bonding enhancement portion 200 can be formed through an electroplating process.

[0108] Figure 9 Shows a flowchart showing a method of forming a bonding enhancement portion through an electroplating process.

[0109] Referring to Figure 9, first, in operation S210, a plurality of plating seeds can be formed on the upper surface of the electrode substrate 100.

[0110] The plating seeds can be parts that serve as anodes during electroplating, can be areas where plating metal precipitates, and can include the same material as the plating metal.

[0111] For example, by patterning a metal film including the same material as the plating metal, plating seeds having the shape of metal pads can be formed in a matrix on the upper surface of the electrode substrate 100. Since plating is performed by cumulative precipitation, the bonding enhancement part 200 can grow upward from the plating seeds.

[0112] The plating gap for setting the plating seeds can be such that the gap of the bonding enhancement part 200 formed by the growth from the plating seeds is also set according to the plating gap. By appropriately setting the plating gap of the plating seeds, the gap of the bonding enhancement part 200 formed in the subsequent plating process can be controlled.

[0113] For example, the plating seeds can be formed on the electrode substrate 100 to have a plating gap of about 1 μm to about 5 μm.

[0114] The plating seeds can include the same material as the electrode substrate 100. For example, if the electrode substrate 100 includes Cu, the plating seeds can also include Cu to obtain uniformity and reduce or prevent the possibility of cracking caused by the difference in physical properties between the electrode substrate 100 and the bonding enhancement part 200.

[0115] After that, in operation S220, the plating metal material can grow from the plating seeds by performing a plating process, and a protrusion 250 having a plating height H (e.g., a predetermined plating height) can be formed from the upper surface of the electrode substrate 100.

[0116] For example, the electrode substrate 100 including the plating seeds is immersed in an electrolytic solution in which plating metal ions are dissolved, and a current is applied thereto. The plating ions electrochemically separated from the electrolytic solution precipitate on the plating seeds.

[0117] In one or more embodiments, the thickness and shape of the deposited plating can be controlled by adjusting the applied voltage or current, the type of electrolytic solution, the concentration of the electrolytic solution, the concentration of the transported ions (pH), etc.

[0118] Protrusions 251, 252, 253, and 254 having various shapes as shown in Figure 3 , Figure 4 , Figure 5 and Figure 6 can be formed on the upper surface of the electrode substrate 100, and the bonding enhancement part 200 growing from the plating seeds can be formed.

[0119] For example, the height of the protrusion 250 of the adhesion enhancement part 200 protruding from the electrode substrate 100 can be controlled by adjusting the amount of the plating metal deposited on the plating seed. The protrusion 250 can grow to have a plating height of about 1 μm to about 5 μm from the upper surface of the electrode substrate 100.

[0120] Figure 10 A scanning electron microscope (SEM) image is shown, which shows an electrode substrate with protrusions formed by the Figure 9 electrolytic plating process shown in

[0121] Referring to Figure 10 , as a result of the electrolytic plating, a columnar protrusion 251 having a gap G (e.g., a predetermined gap) and a height H (e.g., a predetermined height) is formed on the upper surface of the electrode substrate 100.

[0122] As described above, the electrode substrate 100 can have a thickness of about 10 μm to about 50 μm, and the columnar protrusions 251 can be formed in a matrix form on the entire upper surface of the electrode substrate 100 to have a gap G and a height H of about 1 μm to about 5 μm.

[0123] Figure 10 The SEM image shown in

[0124] Figure 11 shows a flowchart of a method for forming an adhesion enhancement part by an etching process.

[0125] Referring to Figure 11 , first, in operation S230, a line-shaped mask pattern is formed on the surface of the electrode substrate 100.

[0126] For example, after forming a photoresist film on the electrode substrate 100, the mask pattern can be formed by an exposure process.

[0127] After loading the electrode substrate 100 into the deposition chamber, a photoresist film can be formed by depositing the photoresist at a uniform concentration. The electrode substrate 100 including the photoresist film can be loaded into an exposure apparatus, and an exposure process can be performed using a reticle having a line-shaped exposure area.

[0128] In one or more embodiments, the exposed areas are dissolved in the sol, and the unexposed areas can remain as a photoresist film. The portions of the photoresist film dissolved in the sol can be removed by a developing process, and a photoresist pattern having a line shape can be obtained.

[0129] The photoresist pattern can be used as a mask pattern in a subsequent etching process.

[0130] Subsequently, in operation S240, an etching process using the mask pattern as an etching mask can remove the electrode substrate 100 exposed through the mask pattern to a depth (e.g., a predetermined depth), and trenches can be formed.

[0131] In one or more embodiments, trenches 215a having this depth (e.g., a predetermined depth) and regularly spaced apart from each other by a gap in a direction perpendicular to the extending direction can be formed in the upper surface of the electrode substrate 100.

[0132] After that, in operation S250, the mask pattern can be removed from the electrode substrate 100, and a remaining matrix material portion 215b defined by the trenches 215a can be formed.

[0133] The areas of the electrode substrate 100 covered with the mask pattern and not removed in the etching process are formed as the remaining matrix material portions 215b each located between adjacent trenches 215a. Two side portions of the remaining matrix material portion 215b are defined by the trenches 215a, and the trenches 215a and the remaining matrix material portion 215b are alternately positioned.

[0134] In one or more embodiments, a line pattern 215 is formed in the upper surface of the electrode substrate 100, and the trenches 215a having this depth (e.g., a predetermined depth) and the remaining matrix material portions 215b are alternately positioned in the line pattern 215.

[0135] The trenches 215a can be formed to have a depth D of about 1 μm to about 5 μm.

[0136] Subsequently, in operation S300 (e.g., see Figure 8 ), a dry electrode portion 300 is formed by repeatedly rolling the electrode powder EP, in which an electrode active material, a conductive material, and a binder are mixed.

[0137] The film-shaped electrode portion 300 can be formed using the rolling device as described above with reference to Figure 7 .

[0138] The electrode powder EP is formed into an electrode portion 300 having a thickness (e.g., a predetermined thickness) by passing between the pressing rollers 10. The pressing rollers 10 can be implemented as multiple roller pairs with different gaps, and can be configured such that the thickness of the electrode portion gradually decreases when moving from a pair of pressing rollers 10 with a wider gap to another pair of pressing rollers 10 with a narrower gap.

[0139] For example, the electrode portion 300 is implemented as a dry electrode layer manufactured by a dry process in which a dispersant for dispersing electrode components (such as active material, conductive material, and / or binder) is not used. The electrode powder EP can be ground without a dispersion solvent to be provided as a powder, and can be formed into the electrode portion 300 under the high pressure applied by the pressing rollers 10. For example, the electrode portion 300 can be provided as a dry electrode film.

[0140] After that, in operation S400 (e.g., see Figure 8 ), the dry electrode portion 300 is bonded to the electrode substrate 100 to be in direct contact with the bonding enhancement portion 200.

[0141] Figure 12 Schematically shown is a laminating device for manufacturing Figure 1 the electrode structure shown in

[0142] The laminating device shown in Figure 12 can be used to thermally press the electrode substrate 100 and the electrode portion 300.

[0143] First, by feeding the electrode substrate 100 including the bonding enhancement portion 200 and the dry electrode portion 300 to pass between a pair of laminating rollers 20, the bonding enhancement portion 200 is extruded to penetrate the electrode active material.

[0144] The electrode substrate 100 can be supplied from a first supply end to be fed between the laminating rollers 20, and the dry electrode portion 300 can be supplied from a pair of second supply ends to be respectively extruded onto the upper surface and the lower surface of the electrode substrate 100.

[0145] As described above, the bonding enhancement portions 200 are respectively formed on the upper surface and the lower surface of the electrode substrate 100, and the electrode portion 300 can be extruded by the laminating rollers 20 such that the bonding enhancement portions 200 penetrate the electrode portion 300.

[0146] In one or more embodiments, different from the related art laminating process in which a bonding layer such as an undercoat layer is located between the electrode portion and the electrode substrate, the electrode portion 300 and the electrode substrate 100 according to the present disclosure can be extruded at a lower pressure because no bonding layer is provided.

[0147] Figure 13shows a SEM image which shows the state where the electrode part is pressed into the Figure 10 electrode substrate shown in

[0148] As Figure 13 shown, if the electrode part 300 is pressed into the Figure 10 electrode substrate 100 having column-shaped protrusions 251 shown in, the column-shaped protrusions 251 can penetrate into the active material of the electrode part 300 to surround the side surface of the bonding reinforcement part 200. In one or more embodiments, the column-shaped protrusions 251 can be partially deformed by the pressing force to an extent without damage, and can be combined or tilted. For example, portions of adjacent column-shaped protrusions 251 can be tilted towards each other to form combined protrusions 251a, and the upper surface can be increased by the combination. The electrode part 300 in contact with the upper surface of the combined protrusions 251a can include a flat portion 301 extending horizontally, and can have an increased frictional force in the flat portion 301 where the contact area is increased.

[0149] In one or more embodiments, the gap G between the combined protrusions 251a and the adjacent column-shaped protrusions 251 can be increased from the gap before combination. The electrode part 300 can include an extension part 302, and the extension part 302 is sufficiently inserted through the increased gap to contact the side surfaces of the column-shaped protrusions 251 and the combined protrusions 251a that define the increased gap.

[0150] In one or more embodiments, the electrode part 300 can contact the side surfaces of the combined protrusions 251a and the column-shaped protrusions 251 that are located between the combined protrusions 251a and the column-shaped protrusions 251 to increase the frictional force.

[0151] When the electrode substrate 100 and the electrode part 300 are pressed, the laminating roller 20 can be heated so that the electrode substrate 100 and the electrode part 300 can be heated using the laminating roller 20. The electrode substrate 100 and the electrode part 300 can be bonded by hot pressing.

[0152] In one or more embodiments, the laminating roller initially at about 20 °C can be heated in a temperature range of about 25 °C to about 150 °C. For example, since the undercoat layer coating is not located between the electrode substrate 100 and the electrode part 300, heat transfer between the electrode substrate 100 and the electrode part 300 can be performed more effectively. Compared with the laminating process of the related art in which the undercoat layer coating is positioned, the temperature of the laminating roller 20 can be kept relatively low.

[0153] In one or more embodiments, the Figure 1 electrode structure 500 shown in can be manufactured.

[0154] Although no separate adhesive layer is provided between the electrode substrate 100 and the dry electrode portion 300, the electrode substrate 100 and the dry electrode portion 300 can be firmly bonded by the frictional force of the adhesion enhancing portion 200 provided on the electrode substrate 100, and the stability of the electrode structure 500 can be improved.

[0155] According to the electrode structure and its manufacturing method as described above, even if additional adhesive layers such as an undercoat layer are omitted, the electrode portion 300 and the electrode substrate 100 can be firmly joined by enhancing the adhesive force between the electrode portion 300 and the electrode substrate 100 using the adhesion enhancing portion 200 located on the electrode 100, and the stability can be improved while reducing the undercoat layer coating cost in the manufacturing process of the dry electrode structure 500.

[0156] The dry electrode substrate can correspond to the current collector of the Li secondary cell, and the dry electrode portion can include the active material of the Li secondary cell.

[0157] Although the present disclosure has been described above with respect to embodiments of the present disclosure, the present disclosure is not limited thereto. Those skilled in the art can make various equivalent modifications and changes thereto within the spirit of the present disclosure and the scope equivalent to the appended claims, including functional equivalents thereof.

Claims

1. An electrode structure comprising: an electrode substrate comprising a conductive material; A dry electrode portion bonded to the electrode substrate; as well as An adhesion reinforcing portion is provided on the electrode substrate to enhance adhesion between the electrode substrate and the dry electrode portion.

2. The electrode structure according to claim 1, wherein: The adhesion enhancing portion includes a recessed portion recessed downward from an upper surface of the electrode substrate to increase a contact area contacting the dry electrode portion.

3. The electrode structure according to claim 2, wherein: The recessed portion includes a concave portion provided in the upper surface of the electrode substrate and a convex portion convexed compared to the concave portion.

4. The electrode structure according to claim 2, wherein: The recessed portion includes grooves recessed downward from the upper surface of the electrode substrate, and remaining matrix material portions alternating with the grooves.

5. The electrode structure according to claim 2, wherein: The recessed portion has a depth of 1 μm to 5 μm and a width of 1 μm to 5 μm.

6. The electrode structure according to claim 1, wherein: The adhesion enhancing portion includes a protrusion protruding upward from an upper surface of the electrode substrate.

7. The electrode structure according to claim 6, wherein: The protrusion includes a sawtooth shape, a column shape, a hemispherical shape, or a branch shape including branches branching from the column shape.

8. The electrode structure according to claim 6, wherein: The protrusion includes an electrolytic plated portion including the same material as the electrode substrate.

9. The electrode structure according to claim 6, wherein: The protrusions have a height of 1 μm to 5 μm, and Wherein, there is a gap of 1 μm to 5 μm between adjacent protrusions.

10. The electrode structure according to claim 1, wherein: The dry electrode portion includes a dry electrode film produced by a dry electrode process without a dispersant for dispersing an active substance, a conductive material, or a binder.

11. The electrode structure according to claim 10, wherein: The dry electrode portion includes a negative electrode active material, and Wherein, the electrode substrate and the bonding enhancement part include copper film, nickel film, stainless steel film, titanium film, nickel foam, copper foam, polymer substrate coated with conductive metal or a combination thereof.

12. The electrode structure according to claim 10, wherein: The dry electrode portion includes a positive electrode active material, and Wherein, the electrode substrate and the bonding enhancement portion include aluminum.

13. A method for manufacturing an electrode structure, the method comprising: preparing an electrode substrate; forming an adhesive reinforcement portion for enhancing the adhesive force of the electrode substrate by processing the upper surface of the electrode substrate; as well as A dry electrode portion is bonded to the electrode substrate to be in direct contact with the bonding enhancement portion.

14. The method according to claim 13, wherein: The forming of the bonding enhancement portion includes: forming a plating seed on the upper surface of the electrode substrate; and A protrusion having a plating height from the upper surface is formed by depositing a plating metal material on the plating seed through a plating process.

15. The method according to claim 14, wherein: Adjacent plating seeds in the plating seeds have a gap of 1 μm to 5 μm.

16. The method according to claim 14, wherein: The plating height is 1 μm to 5 μm.

17. The method according to claim 13, wherein: The forming of the bonding enhancement portion includes: forming a mask pattern on the upper surface of the electrode substrate; forming grooves having a line shape and spaced apart from each other by partially removing the electrode substrate through an etching process using the mask pattern as an etching mask; and A line pattern including the groove and a remaining matrix substance portion is formed by removing the mask pattern from the electrode substrate.

18. The method according to claim 17, wherein: The forming of the mask pattern includes: forming a photoresist film on the electrode substrate; performing an exposure process on the photoresist film to have the line shape; and The photoresist film is developed.

19. The method of claim 13, further comprising forming the dry electrode part by repeating a calendaring process on an electrode powder in which an electrode active material, a conductive material, and a binder are mixed.

20. The method according to claim 19, wherein: The bonding of the dry electrode portion to the electrode substrate includes a lamination process of heat-pressing the electrode substrate and the dry electrode portion by feeding the electrode substrate and the dry electrode portion between a pair of lamination rollers.

Images