Electrode, method for manufacturing same, and secondary battery including same

Abstract

The present invention relates to a method for manufacturing an electrode, the method comprising: step S1 of forming an inclined surface descending from the inside in the outside direction on at least one end portion with reference to the width direction of an electrode composite film through a first rolling roll including a cutting device; step S2 of heating and pressing the electrode composite film by using the first rolling roll and a second rolling roll; step S3 of putting the electrode composite film and a current collector into a lamination unit including the second rolling roll and a third rolling roll and laminating same; and step S4 of coating an insulating liquid on the current collector so as to be adjacent to the inclined surface with reference to the width direction of the current collector.

Description

Electrode, method of manufacturing the same, and secondary battery including the same

[0001] Cross-citation with related applications

[0002] The present application claims the benefit of priority based on Korean Patent Application No. 10-2024-0181038 filed December 6, 2024 and Korean Patent Application No. 10-2025-0191456 filed December 5, 2025, the entire contents of which are incorporated herein.

[0003]

[0004] Technology field

[0005] The present invention relates to an electrode, a method for manufacturing the same, and a secondary battery including the same.

[0006]

[0007] Secondary batteries are used not only in small products such as digital cameras, P-DVDs, MP3 players, mobile phones, PDAs, portable game devices, power tools, and E-bikes, but also in large products requiring high output such as electric vehicles and hybrid vehicles, as well as in power storage devices that store surplus power or new and renewable energy and backup power storage devices.

[0008] Typically, a secondary battery is manufactured by applying an electrode active material slurry to a positive electrode current collector and a negative electrode current collector to form an electrode active material layer, then manufacturing a positive electrode and a negative electrode through drying and rolling processes, and then stacking them on both sides of a separator to form an electrode assembly of a predetermined shape, and then housing the electrode assembly in a battery case, injecting an electrolyte, and sealing.

[0009] Meanwhile, during the drying process of the electrode active material slurry, defects such as pinholes or cracks may be induced in the electrode active material layer formed on the current collector as the solvent contained in the slurry evaporates. In addition, since the inner and outer parts of the electrode active material slurry are not dried uniformly during the drying process, there is a risk that the electrode quality may deteriorate due to a powder floating phenomenon caused by the difference in solvent evaporation rates, that is, powders in the parts that dry first rise and form a gap with the parts that dry relatively later.

[0010] To solve the above problem, drying devices capable of controlling the evaporation rate of the solvent are being considered so that the inside and outside of the electrode active material slurry can be dried uniformly; however, these drying devices are very expensive and require significant cost and time to operate, which is disadvantageous in terms of manufacturing processability.

[0011] On the other hand, the solvent included in conventional electrode active material slurries is N-methyl-2-pyrrolidone (NMP), which has a high boiling point and requires high thermal energy and a very long drying oven to dry, making it very unfavorable for mass production. In addition, N-methyl-2-pyrrolidone (NMP) is a toxic substance and is harmful to living organisms, so it has the disadvantage of not being environmentally friendly.

[0012] Therefore, there is a recent trend of active research on dry electrodes that manufacture electrodes without using solvents. The above-mentioned dry electrode is generally manufactured by laminating a free-standing type electrode composite film, which is manufactured in a sheet form and includes an electrode active material, a binder, a conductive material, etc., onto a current collector. This electrode composite film includes a process of first mixing the electrode active material, a carbon material as a conductive material, and a fiberizable binder together using a blender or similar device, then fiberizing the binder by applying shear force through a process such as jet-milling or kneading, and finally calendering the obtained mixture into a film form to manufacture a free-standing film.

[0013] Meanwhile, if contact occurs between the anode and cathode within the electrode assembly, a short-circuit current flows, reaching an abnormally high temperature state, which can cause ignition or explosion. In other words, under normal circumstances, the anode and cathode within the electrode assembly should be insulated by a separator; however, if the separator shrinks or breaks, the aforementioned short-circuit phenomenon occurs. At this time, since the short circuit is highly likely to occur in the uninsulated area near the end of the current collector, a process is undertaken to form an insulating layer by coating an insulating liquid or placing insulating tape on the uninsulated area of ​​the current collector to prevent this.

[0014] However, when manufacturing the above dry electrode, the electrode powder is compressed to produce an electrode composite film having a sheet shape, and then the electrode composite film is cut to a certain size and placed on a current collector; thus, unlike a wet electrode, it has a shape without edge sliding. Consequently, when an insulating liquid is coated on one side of the electrode composite film, an overlap phenomenon occurs in which the insulating liquid is placed on the upper side of the electrode composite film due to inevitable process errors.

[0015] When the above-mentioned overlap phenomenon occurs in a dry electrode, a portion of the insulating liquid is positioned higher than the electrode composite film, resulting in a fat-edge phenomenon where only a portion of the thickness on one side of the electrode composite film becomes thicker. In such cases, defects such as compression or tearing of the current collector may occur, and the detachment of the electrode composite film and / or insulating coating layer, as well as damage to the current collector during rolling, may result. These defects occur more frequently and significantly when the dry electrode is stored in a jumbo-roll form.

[0016] Therefore, there is a need for an electrode and a method for manufacturing the same that can achieve excellent processability and insulation while preventing the aforementioned fat-edge phenomenon.

[0017]

[0018] One objective of the present invention is to solve the above-mentioned problems by providing a method for manufacturing an electrode that can maintain insulation while achieving excellent processability without causing a fat edge, by trimming at least one end portion of an electrode composite film under certain conditions in a specific rolling roll.

[0019]

[0020] In addition, one objective of the present invention is to solve the above-mentioned problems by controlling the angle of inclination of the inclined surface of the electrode composite film included in the dry electrode, thereby providing an electrode that can maintain insulation without causing a fat edge even if a part of the insulating coating layer comes into contact with the inclined surface, and a secondary battery including the same.

[0021]

[0022] [1] The present invention provides a method for manufacturing an electrode, comprising: a first rolling roll including a cutting device, forming an inclined surface that descends from the inner side to the outer side at at least one end of the electrode composite film in the width direction; a second rolling roll including a first rolling roll and a second rolling roll including a cutting device, and a third rolling roll including a first rolling roll including a cutting device, and a second rolling roll including a first rolling roll including a cutting device, and a second rolling roll including a first rolling roll and a second rolling roll including a lamination part including a second rolling roll and a third rolling roll including a lamination part

[0023] [2] In the above [1], the cutting device may include one or more selected from the group consisting of a shear knife and a score knife.

[0024] [3] In the present invention [1] or [2], the angle formed between the inclined surface and the horizontal plane of the first rolling roll may be 80° or less.

[0025] [4] In at least one of [1] to [3], the angle formed between the inclined surface and the horizontal plane of the first rolling roll may be 30° to 45°.

[0026] [5] In at least one of [1] to [4], the peripheral speed ratio of the second rolling roll to the first rolling roll may be 1.01 to 1.20.

[0027] [6] In at least one of [1] to [5] of the present invention, the thickness of the insulating liquid may be 20 μm or less.

[0028] [7] The present invention may further include step S5 of drying the insulating liquid in at least one of [1] to [6].

[0029] [8] In at least one of [1] to [7], the electrode composite film can be manufactured by a method comprising the following steps A1 to A4.

[0030] (A1) a step of forming a composite composition by mixing an electrode active material and a binder; (A2) a step of forming a mixed aggregate by kneading the composite composition while applying shear force; (A3) a step of manufacturing an electrode powder by crushing the mixed aggregate; and (A4) a step of manufacturing a powder sheeting film by sheeting the electrode powder.

[0031] [9] An electrode is provided that includes: a current collector; an electrode composite film disposed on the current collector; and an insulating coating layer disposed on the current collector; wherein the electrode composite film has an inclined surface that descends from the inside to the outside at at least one end portion in the width direction of the electrode composite film, and the insulating coating layer is formed to be in contact with the inclined surface in part, and the angle of inclination of the inclined surface is 70° or less.

[0032]

[0010] In the present invention [9], the angle of inclination of the inclined surface may be 25° to 40°.

[0033]

[0011] In the present invention [9] or

[0010] , the thickness of the electrode composite film may be 20 μm to 200 μm.

[0034]

[0012] In at least one of [9] to

[0011] , the width of the insulating coating layer may be 1 mm to 8 mm.

[0035]

[0013] In at least one of [9] to

[0012] of the present invention, the thickness of the insulating coating layer may be 20 μm or less.

[0036]

[0014] In at least one of [9] to

[0013] , the maximum height of the insulating coating layer may be less than the maximum height of the electrode composite film.

[0037]

[0015] The present invention provides a secondary battery comprising at least one electrode among [9] to

[0014] .

[0038]

[0039] In the case of the electrode and the method for manufacturing the electrode according to the present invention, at least one end portion of the electrode composite film is trimmed under certain conditions in a specific rolling roll, thereby forming an inclined surface descending from the inner side to the outer side at at least one end portion based on the width direction of the electrode composite film, while achieving excellent processability, and as a result, even when an insulating coating layer is formed, the fat-edge phenomenon is not caused. Consequently, defects such as compression or tearing of the current collector are not caused, and excellent safety is achieved by preventing detachment of the electrode composite film and / or insulating coating layer and damage to the current collector during rolling.

[0040]

[0041] The drawings attached to this specification illustrate preferred embodiments of the present invention and serve to help to better understand the technical concept of the present invention together with the description of the invention above; therefore, the present invention is not to be interpreted as being limited only to the matters described in such drawings. Meanwhile, the shape, size, scale, or ratio of elements in the drawings included in this specification may be exaggerated to emphasize a clearer explanation.

[0042] Figure 1 is a schematic diagram illustrating the overlap and fat-edge phenomena.

[0043] FIG. 2 is a schematic diagram illustrating an electrode according to one embodiment of the present invention.

[0044] FIG. 3 is a schematic diagram illustrating an electrode according to one embodiment of the present invention.

[0045] Figure 4 is a schematic diagram illustrating the trimming process during conventional electrode manufacturing.

[0046] Figure 5 is a schematic diagram illustrating the trimming process during conventional electrode manufacturing.

[0047] Figure 6 is a schematic diagram illustrating the trimming process during conventional electrode manufacturing.

[0048] Figure 7 is a schematic diagram illustrating the trimming process during conventional electrode manufacturing.

[0049] Figure 8 is a schematic diagram illustrating one end portion of an electrode composite film during conventional electrode manufacturing.

[0050] Figure 9 is a schematic diagram illustrating one end portion of the electrode composite film during conventional dry electrode manufacturing.

[0051] FIG. 10 is a schematic diagram illustrating a trimming process for an electrode according to one embodiment of the present invention.

[0052] FIG. 11 is a schematic diagram illustrating a trimming process for an electrode according to one embodiment of the present invention.

[0053] FIG. 12 is a schematic diagram illustrating a trimming process for an electrode according to one embodiment of the present invention.

[0054] FIG. 13 is a schematic diagram illustrating one end portion of an electrode composite film within an electrode according to one embodiment of the present invention.

[0055]

[0056] The present invention will be described in more detail below.

[0057] Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0058] In this specification, "composite composition" refers to a mixture comprising an electrode active material, a binder, and optionally a conductive material, which is physically mixed to form a uniform dispersed phase. As a product of the mixing process according to this specification, it may be a powdered mixture and may substantially not involve a solvent. Here, "substantially not involving a solvent" means that no solvent is introduced or only a minute amount of solvent is introduced during the mixing of the composite composition.

[0059] In this specification, “mixed aggregate” refers to a product of a mixing process (kneading process) according to this specification in which the above composite composition is subjected to shear force and the binder is fiberized, and the powdered mixture is combined or linked with one another to be converted into an aggregate in a dough-like state, which may substantially contain a solid content close to 100%, and in some cases may contain a small amount of solvent.

[0060] In this specification, “powder for electrode” refers to a material in which the mixed aggregate is crushed to form a powder with a smaller particle size, and may mean an electrode material in powder form comprising an electrode active material, a binder, and optionally a conductive material.

[0061] In this specification, the term "electrode composite film" may refer to a free-standing type single sheet manufactured using an "electrode composite" comprising an electrode active material and a binder without the involvement of a solvent, or an electrode composite layer laminated onto a current collector. In this specification, the term "free-standing type" means that it can maintain an independent form without relying on other components and can be moved or handled on its own. As described below, the electrode composite film may be formed by accumulating electrode powders by compression.

[0062] In this specification, "powder sheeting film" refers to a film formed after the electrode powder passes through a rolling roll for the first time in a roll-to-roll process to form a sheet shape; it may be a self-supporting sheet, but may be a sheet with relatively weak self-supporting capacity. Here, "powder sheeting" means that the electrode powder is formed into a self-supporting sheet shape by the rolling roll of a roll-to-roll process, and "sheeting" may have substantially the same meaning as calendering. It may refer to a process performed during the process of manufacturing the powder sheeting film into an electrode composite film, and may mean a process of rolling the powder sheeting film.

[0063] In this specification, the “three-dimensional fiber network structure” refers to a structure formed by the fiberization of a binder during the process of sheet forming from a composite composition comprising an electrode active material and a binder into an electrode composite film, and may mean a structure in which a plurality of fibers are connected in the up, down, left, and right directions at a plurality of points. The three-dimensional fiber network structure may refer to various forms of structures that can function as a support, enabling the electrode composite film to be a self-standing film, by having a fine fibrous binder form a framework. At this time, the electrode active material and, optionally, a conductive material may be accommodated within the pores formed in the three-dimensional fiber network structure.

[0064] In this specification, "average particle size" refers to the particle size (D) at 50% of the volume cumulative amount of the volume cumulative particle size distribution of the powder to be measured. 50...means ). The above average particle size can be measured using the laser diffraction method. The laser diffraction method generally enables the measurement of particle sizes ranging from the submicron range to several millimeters, and allows for the acquisition of results with high reproducibility and high resolution. For example, the measurement can be performed by dispersing the powder to be measured in a dispersion medium, introducing it into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000), irradiating it with ultrasound of approximately 28 kHz at an output of 60 W, obtaining a volume-cumulative particle size distribution graph, and then determining the particle size corresponding to 50% of the volume-cumulative amount. Furthermore, in this specification, “D v10 " refers to the particle size at 10% of the volume cumulative amount of the volume cumulative particle size distribution of the powder to be measured.

[0065] In this specification, the porosity can be calculated using the following mathematical formula A.

[0066] [Mathematical Formula A]

[0067] Porosity (%) = {1 - (Electrode Density / True Density)} × 100

[0068] In the above mathematical formula A, the true density is a calculated density derived from the density and mass ratio of each constituent material forming the powder-sheeting film or electrode composite film under the assumption that it does not contain pores, and the electrode density is the measured density of the powder-sheeting film or electrode composite film measured by taking a sample of the powder-sheeting film or electrode composite film of a certain size.

[0069] In the present invention, “specific surface area (m 2 / g)” is measured by the BET method, and specifically, can be calculated from the amount of nitrogen gas adsorbed at liquid nitrogen temperature (77K) using BEL Japan’s BELSORP-mino II.

[0070]

[0071] As a result of repeated research on an electrode and a method for manufacturing an electrode that can prevent the fat-edge phenomenon while achieving excellent processability, the inventors discovered that by trimming at least one end of an electrode composite film under certain conditions in a specific rolling roll, and forming an inclined surface descending from the inner side to the outer side at at least one end with respect to the width direction of the electrode composite film, excellent safety can be achieved without causing defects such as compression or tearing of the current collector, and without detachment of the electrode composite film and / or insulating coating layer or damage to the current collector during rolling, thereby completing the present invention.

[0072]

[0073] The present invention will be described in detail below.

[0074] The electrode according to the present invention, the method for manufacturing the same, and the secondary battery including the same comprise at least one of the configurations disclosed below, and may comprise any combination of technically feasible configurations among the configurations below.

[0075]

[0076] Method for manufacturing an electrode

[0077] Hereinafter, a method for manufacturing an electrode according to the present invention will be described.

[0078] A method for manufacturing an electrode according to the present invention comprises: a step S1 of forming an inclined surface descending from the inner side to the outer side at at least one end portion with respect to the width direction of an electrode composite film through a first rolling roll including a cutting device; a step S2 of heating and pressing the electrode composite film using the first rolling roll and the second rolling roll; a step S3 of laminating the electrode composite film and the current collector by feeding them into a roll press unit including the second rolling roll and the third rolling roll; and a step S4 of coating an insulating liquid on the current collector so as to be adjacent to the inclined surface with respect to the width direction of the current collector.

[0079]

[0080] In the case of electrodes manufactured by a dry method, unlike wet electrodes in which an electrode active material layer is manufactured by coating a slurry onto a current collector, the process involves heating and pressing electrode powder to form a powder sheeting film and / or an electrode composite film in a sheet shape, removing both ends of the film, and then placing it on the current collector; thus, the film has a shape without edge sliding. Therefore, when an insulating coating layer is formed on the uncoated portion of the current collector to prevent short circuits, an overlap phenomenon occurs in which the insulating liquid is placed on the upper part of the electrode composite film due to inevitable process errors, as shown in Fig. 1.

[0081] As described above, when an overlap phenomenon occurs in the electrode, a portion of the insulating liquid is positioned higher than the electrode composite film, resulting in a fat-edge phenomenon where only a portion of the thickness on one side of the electrode composite film becomes thicker. In such cases, defects such as compression or tearing of the current collector may occur, and the detachment of the electrode composite film and / or insulating coating layer, as well as damage to the current collector during rolling, may occur more frequently and significantly when the electrode is stored in a jumbo-roll form.

[0082] Accordingly, the present invention aims to provide a method for manufacturing an electrode in a roll-to-roll process for manufacturing an electrode, wherein the electrode is manufactured such that an electrode composite film having an inclined surface formed descending from the inner side to the outer side is finally attached to a current collector, and the manufacturing process can be performed continuously.

[0083] As described above, when the electrode composite film is placed on the current collector, the overlap phenomenon of the insulating coating layer caused by inevitable process errors as shown in FIGS. 2 and 3 can be prevented, thereby enabling excellent safety and processability.

[0084]

[0085] Hereinafter, each step will be explained in more detail with reference to FIGS. 1 to 13.

[0086]

[0087] (1) S1 stage

[0088] First, step S1 describes forming an inclined surface descending from the inner side to the outer side at at least one end portion with respect to the width direction of the electrode composite film through a first rolling roll including a cutting device.

[0089]

[0090] Referring to FIGS. 6 to 7 and 11 to 13, it can be seen that a sloping surface descending from the inner side to the outer side is formed at at least one end portion with respect to the width direction of the electrode composite film (100) through a first rolling roll (301) including a cutting device (401).

[0091] At this time, the inclined surface descending from the inner side to the outer side is formed at one end of the electrode composite film (100), and the direction can be seen in detail through FIGS. 6 to 7 and 11 to 13.

[0092] Meanwhile, referring to FIG. 5, when the electrode composite film (100) is trimmed in a vertical direction without forming an inclined surface descending from the inner side to the outer side, as shown in FIG. 8, the electrode composite film (100) without an inclined surface is formed on the current collector (10), so the occurrence of an overlap of the insulating coating layer due to process error cannot be prevented.

[0093]

[0094] According to one embodiment of the present invention, the cutting device (401) may include one or more selected from the group consisting of a shear knife (402) and a score knife (403), and preferably may include a shear knife (402). For example, the shear knife (402) may be a knife having one inclined surface formed at one end, as shown in FIG. 5, and the score knife (403) may be a knife having two inclined surfaces formed at one end, as shown in FIG. 7. When the above conditions are satisfied, it may be desirable in that an inclined surface can be formed at one end of the electrode composite film (100) in a certain shape, and in particular, when the shear knife (402) is included, it may be desirable in that burrs generated at the cutting portion of the electrode composite film (100) are prevented, making the cut surface smooth and reducing defects.

[0095]

[0096] According to one embodiment of the present invention, when the cutting device (401) includes a shear knife (402), the inclined surface formed on the shear knife (402) may face inward toward the electrode composite film (100). When the above condition is satisfied, it may be preferable in that an inclined surface that is not perpendicular can be formed at one end of the electrode composite film (100).

[0097]

[0098] According to one embodiment of the present invention, the angle formed between the inclined surface and the horizontal plane of the first rolling roll (301) may be 80° or less, preferably 80° or less, 70° or less, 60° or less, 50° or less, or 45° or less, and may be 1° or more, 5° or more, 10° or more, 15° or more, 20° or more, 25° or more, or 30° or more, and more preferably 30° to 45°. When the above range is satisfied, an inclined surface having an appropriate inclination angle can be formed on the electrode composite film (100), thereby preventing an overlap phenomenon when forming an insulating coating layer later, while also preventing a decrease in energy density due to excessive cutting of the electrode composite film (100). For example, the angle formed between the inclined surface and the horizontal plane of the first rolling roll (301) is the angle (angle of inclination, θ) formed between the inclined surface of the electrode composite film (100) shown on the left side of the first rolling roll (301) and the horizontal plane of the first rolling roll (301). s ) can be.

[0099]

[0100] (2) S2 stage

[0101] Next, step S2, which involves heat-pressing the electrode composite film (100) using the first rolling roll (301) and the second rolling roll (302), is described.

[0102] The above S2 step is a step of calendering an electrode composite film (100) having an inclined surface formed descending from the inner side to the outer side, and the calendering may be a step of heat pressing using a roll press unit including a pair of rolling rolls.

[0103] Even if an electrode composite film (100) is manufactured with an inclined surface that descends from the inner side to the outer side as shown in FIGS. 4, 6, and 7, if the electrode composite film (100) and the current collector (10) are laminated without going through step S2, it can be seen that the electrode composite film (100) placed on the current collector (10) as shown in FIG. 9 has an inclined surface that rises from the inner side to the outer side. In such a case, when an insulating liquid is discharged from the upper part of the current collector and the electrode composite film, an overlap phenomenon in which the insulating liquid is placed on the upper part of the electrode composite film cannot be prevented.

[0104] That is, one feature of the present invention is that, instead of laminating immediately after forming an inclined surface descending from the inner side to the outer side with respect to the electrode composite film (100), heat pressing is performed using the first rolling roll (301) and the second rolling roll (302), and then step S3 described later is performed, thereby finally preventing an over-lap phenomenon caused by the insulating liquid.

[0105]

[0106] According to one embodiment of the present invention, the peripheral speed ratio of the second rolling roll (302) to the first rolling roll (301) may be 1.01 to 1.20, preferably 1.01 to 1.10, and more preferably 1.02 to 1.05. For example, the peripheral speed of the second rolling roll (302) is faster than the peripheral speed of the first rolling roll (301), while satisfying a certain range. When the above range is satisfied, the elongation rate of the film can be maintained within an appropriate range, thereby preventing the appearance of burrs and preventing film edge defects, so that excellent processability and electrochemical properties can be achieved.

[0107]

[0108] (3) S3 stage

[0109] Next, step S3, in which the electrode composite film (100) and the current collector (10) are fed into a lamination section including a second rolling roll (302) and a third rolling roll (303) to perform lamination, is described. Through this, the electrode composite film (100) is rolled onto the current collector (10), thereby enabling the manufacture of a dry electrode in which the electrode composite film is placed on the current collector (10).

[0110] The above lamination may be performed by rolling and attaching the electrode composite film (100) onto the current collector (10). The above lamination may be performed by a roll press method using a lamination unit comprising a calendering roll, a rolling roll and / or a lamination roll, and preferably, by a roll press method using a lamination unit comprising a second rolling roll (302) and a third rolling roll (303).

[0111]

[0112] According to one embodiment of the present invention, the peripheral speed ratio of the third rolling roll (303) to the second rolling roll (302) may be 1:1 to 1:10, preferably 1:1 to 1:5, and more preferably 1:1 to 1:2. When the above range is satisfied, the electrode composite film and the current collector are appropriately rolled, so that excellent adhesion between the electrode composite film and the current collector can be achieved.

[0113]

[0114] According to one embodiment of the present invention, the second rolling roll (302) and the third rolling roll (303) rolls can each be independently maintained at a temperature of 20°C to 200°C.

[0115]

[0116] (4) S4 stage

[0117] Next, step S4 of coating an insulating liquid on the current collector (10) so as to be adjacent to the inclined surface in the width direction of the current collector (10) is described.

[0118] The above insulating liquid is a liquid for subsequently forming an insulating coating layer, and it is sufficient if it can be coated on the current collector (10) and the inclined surface while ensuring insulating performance, and its material or composition is not particularly limited. The above insulating liquid may be a viscous composition containing an insulating material.

[0119]

[0120] According to one embodiment of the present invention, the insulating liquid may include an insulating material and may include, for example, one or more selected from the group consisting of boehmite, tannic acid, styrene butadiene rubber (SBR), polyethylene terephthalate (PET), polyimide (PI), and polypropylene (PP). When the above conditions are satisfied, excellent insulating properties can be achieved.

[0121]

[0122] According to one embodiment of the present invention, the thickness of the insulating liquid may be 20 μm or less, preferably 0.5 μm to 10 μm, and more preferably 0.5 μm to 5 μm. When satisfying the above range, it may be desirable in that excellent insulation performance can be achieved by preventing the overlap phenomenon while subsequently forming an insulating coating layer of appropriate thickness.

[0123]

[0124] According to one embodiment of the present invention, the manufacturing method according to the present invention may further include a step S5 of drying the insulating solution. When the above condition is satisfied, the insulating solution can be formed into an insulating coating layer, which may be desirable in terms of achieving excellent insulation properties.

[0125]

[0126] According to one embodiment of the present invention, the electrode composite film may include an electrode active material and a binder having a three-dimensional fiber network structure, and preferably may include an electrode active material, a binder having a three-dimensional fiber network structure and a conductive material.

[0127] A detailed description of the above electrode active material, binder having a three-dimensional fiber network structure, and conductive material will be provided later.

[0128]

[0129] According to one embodiment of the present invention, the electrode composite film can be manufactured by including steps A1 to A4 as follows.

[0130]

[0131] 1) Level A1

[0132] The step involves mixing an electrode active material and a binder to form a composite composition. Preferably, the mixing is performed so that the electrode active material and the binder are uniformly distributed. Optionally, a conductive material may be further included, and since the mixture is in powder form, the mixing can be performed by various methods that enable simple mixing, without limitation. However, since the method for manufacturing the electrode is a dry method that does not use a solvent, the mixing can be performed by dry mixing, and the materials can be mixed by introducing them into a device such as a mixer or blender.

[0133] At this time, the mixing can be performed in a mixer at 100 rpm to 10,000 rpm for 1 minute to 120 minutes. Preferably, it can be performed at 500 rpm to 5,000 rpm for 5 minutes to 60 minutes, and more preferably at 1,000 rpm to 3,000 rpm for 10 minutes to 60 minutes. When performed within the above range, the materials can be uniformly mixed, thereby improving battery performance.

[0134]

[0135] 2) A2 level

[0136] Next, a step of forming a mixed aggregate by kneading while applying shear force to the above composite composition can be performed. That is, the above A2 step may be a fiberization process of a binder using a binder capable of forming a three-dimensional fiber network structure.

[0137] The above fiberization process can be performed, for example, through mechanical milling or kneading, and there are no particular limitations as long as it is generally performed, but preferably, it can be performed by high-temperature, low-shear kneading, and can be performed through a kneader such as a twin-screw extruder, for example. Through such kneading, the binder (preferably a fiberizable binder) is fiberized, and the electrode active material powders, or optionally powders containing a conductive material, are combined or linked to form a mixed aggregate with 100% solid content.

[0138] The above mixing can be performed at a speed of 10 rpm to 100 rpm, and more specifically at a speed of 20 rpm to 70 rpm. In addition, the above mixing can be performed for 1 minute to 120 minutes, and more specifically at 2 minutes to 60 minutes. When the above range is satisfied, appropriate fiberization can proceed, and a structurally stable three-dimensional fiber network structure can be formed while being fiberized uniformly throughout.

[0139] In addition, the above mixing can be performed under high temperature and pressure conditions higher than atmospheric pressure, and more specifically, under pressure conditions higher than atmospheric pressure.

[0140] More specifically, the above mixing can be performed at a temperature of 50°C to 230°C, preferably 90°C to 200°C. When mixing is performed at a high temperature such as the above range, the fiberization of the binder and agglomeration by mixing can be effectively achieved, and the problem of breakage of the fiberized binder can be appropriately prevented.

[0141] In addition, it can be performed at a pressure above atmospheric pressure, specifically at a pressure of 1 atm to 3 atm, and more specifically at 1.1 atm to 3 atm. When performed within the above range, the problem of breakage of the binder undergoing fiberization can be adequately prevented, and the problem of the density of the aggregate becoming too high can be prevented.

[0142] That is, according to the present invention, when a high-temperature, low-shear mixing process is performed under high temperature and pressure conditions greater than atmospheric pressure instead of high-shear mixing, the effect intended by the present invention can be achieved.

[0143]

[0144] 3) A3 level

[0145] Next, a step of obtaining an electrode powder by crushing the mixed aggregate produced through the above mixing step may be performed. Preferably, a step of manufacturing an electrode powder by crushing the mixed aggregate may be performed.

[0146] Although the mixed aggregate produced through the above mixing process may be immediately pressurized to form a sheet (sheeting, e.g., a calendering process), in this case, the aggregate may need to be pressed under high pressure and high temperature to produce a thin film. Consequently, problems may arise where the film density becomes too high or a uniform film cannot be obtained. Therefore, the mixed aggregate produced as described above can be crushed to produce a powder for electrodes.

[0147] The device used for the above grinding is not particularly limited, but preferably can be performed with a device such as a blender or a grinder.

[0148] The grinding above can be performed at a speed of 1,000 rpm to 15,000 rpm for 5 seconds to 45 minutes, preferably at a speed of 3,000 rpm to 10,000 rpm for 1 minute to 30 minutes. When performed within the above range, sufficient grinding can be achieved to produce powder of a size suitable for film formation, and a large amount of fine powder may not be generated in the mixed aggregate.

[0149] The average particle size of the above electrode powder may be 10㎛ to 3,000㎛, more specifically 50㎛ to 1,500㎛, and even more specifically 100㎛ to 700㎛. When the above range is satisfied, an electrode composite film with uniform thickness and density can be formed, and excellent electrode composite film properties can be secured.

[0150]

[0151] Meanwhile, the above-mentioned electrode powder may additionally include fillers to suppress the expansion of the electrode, although this is not essential. The fillers are not particularly limited as long as they are fibrous materials that do not cause chemical changes in the battery, but examples include at least one selected from olefinic polymers such as polyethylene and polypropylene; and fibrous materials such as glass fibers and carbon fibers.

[0152]

[0153] 4) A4 level

[0154] Next, a step of manufacturing a powder-sheeting film by sheeting the electrode powder can be performed. Preferably, a step of manufacturing an electrode composite film can be performed after manufacturing a powder-sheeting film by heat-pressing the electrode powder. For example, it may include sheet-forming the electrode powder into an electrode composite film.

[0155] The above A4 step may be a process of manufacturing a powder sheeting film or an electrode composite film in the form of a self-standing sheet by heat-pressing the electrode powder obtained as described above using rolling rolls in a roll-to-roll process (calendering process, sheeting process) that includes two or more pairs of rolling rolls.

[0156] The above roll-to-roll process (calendar process) may include a roll press section, and the roll press section may have rolling rolls arranged in pairs facing each other, and multiple such pairs of rolling rolls may be arranged continuously in the roll press section. When multiple rolling rolls are arranged continuously, the temperature and peripheral speed ratio (ratio of rotational speeds of a pair of rolls) of each roll may be the same, or, in this case, the rotational speed ratio of each rolling roll may be independently and appropriately adjusted within a range of 1:1 to 1:10. In addition, the manufactured electrode composite film may be fed back into the roll press section to be adjusted to an appropriate thickness and subjected to heating and pressing 1 to 10 times.

[0157] In one aspect, the above step A4 may include a step of producing a powder sheeting film by powder sheeting the electrode powder (A4a); a step of producing an electrode composite film by calendering the powder sheeting film (A4b); and a step of laminating the electrode composite film with a current collector (A4c). After converting the powder into a sheet in step A4a, the powder may be rolled in step A4b to reduce thickness while improving strength, and to satisfy the porosity and loading amount required for the electrode.

[0158] In addition, the powder sheeting film produced by the above powder sheeting may be subjected to heat pressing 1 to 10 times through the calendering process of step A4b for reasons such as additional fiberization, securing mechanical properties, or controlling porosity. At this time, the peripheral speed ratio between rolls can be appropriately applied within the range of the peripheral speed ratio in powder sheeting, and the number of times can also be appropriately controlled to match the target properties.

[0159] After the 1 to 10 heat pressing processes of step S4b above, the lamination of the current collector and the electrode composite film, which is step S4c, may be performed. The lamination may be a step of rolling and attaching the electrode composite film onto the current collector, and the lamination may be performed by a roll press method using a lamination roller, wherein the lamination roller may be maintained at a temperature of 20°C to 200°C.

[0160] The above lamination may preferably be performed after one or more or two or more heat pressing steps in step S4b, and the current collector may be coated with a conductive primer containing conductive carbon and a binder to improve conductivity and adhesion as described above.

[0161] In one aspect, after the lamination step (S4c), an additional rolling step (S4d) may be included, which may involve performing one or more additional heat pressings to achieve a target porosity.

[0162] When performing a post-rolling process in this manner, it may be preferable in terms of the appearance characteristics and durability of the electrode rather than achieving the final desired porosity before lamination. Porosity control through additional heat pressing can be achieved by controlling the compression ratio by adjusting the roll gap.

[0163]

[0164] According to one embodiment of the present invention, the electrode composite film (100) of step S1 may be fed into a roll press and subjected to heat pressing 1 to 9 times. For example, the electrode composite film (100) may be fed into a roll press and subjected to heat pressing 1 to 9 times before forming an inclined surface, and may be step A4c.

[0165] In addition, for example, the roll press section may have rolling rolls arranged in pairs facing each other, and multiple such pairs of rolling rolls may be arranged continuously in the roll press section. When multiple rolling rolls are arranged continuously, the temperature and peripheral speed ratio (ratio of rotational speeds of a pair of rolls) of each roll may be the same, or the rotational speed ratio of each rolling roll may be independently and appropriately adjusted within a range of 1:1 to 1:10. When the above conditions are satisfied, the electrode composite film can be adjusted to an appropriate thickness while minimizing defects. In addition, the gap between the pairs of rolling rolls may be appropriately adjusted according to the desired thickness of the electrode composite film.

[0166]

[0167] electrode

[0168] Hereinafter, the electrode according to the present invention will be described.

[0169] The electrode according to the present invention comprises: a current collector (10); an electrode composite film (100) disposed on the current collector (10); and an insulating coating layer (110) disposed on the current collector (10). The electrode composite film (10) includes an inclined surface descending from the inner side to the outer side at at least one end portion based on the width direction of the electrode composite film (10), and the insulating coating layer (110) is formed to be in contact with a portion of the inclined surface, and the angle of inclination of the inclined surface is 70° or less.

[0170]

[0171] As described above, unlike wet electrodes in which an electrode active material layer is manufactured by coating a slurry onto a current collector, electrodes manufactured by a dry method undergo a process in which a powder for electrodes is heated and compressed to form a powder sheeting film and / or an electrode composite film in the shape of a sheet, and then the ends of the film are removed and the film is placed on the current collector. Consequently, the film has a shape without edge sliding. Therefore, when an insulating coating layer is formed on the uninsulated part of the current collector to prevent a short circuit, an overlap phenomenon occurs in which the insulating liquid is placed on the upper part of the electrode composite film due to inevitable process errors, as shown in Fig. 1.

[0172] As described above, when an overlap phenomenon occurs in the electrode, a portion of the insulating liquid is positioned higher than the electrode composite film, resulting in a fat-edge phenomenon where only a portion of the thickness on one side of the electrode composite film becomes thicker. In such cases, defects such as compression or tearing of the current collector may occur, and the detachment of the electrode composite film and / or insulating coating layer, as well as damage to the current collector during rolling, may occur more frequently and significantly when the electrode is stored in a jumbo-roll form.

[0173] Accordingly, the present invention aims to provide a healthy electrode in which an overlap phenomenon and a fat-edge phenomenon do not occur by including an inclined surface descending from the inner side to the outer side at at least one end portion based on the width direction of the electrode composite film, and forming an insulating coating layer so as to be in contact with a portion of the inclined surface, and controlling the angle of inclination of the inclined surface to a certain range.

[0174] As described above, when the electrode composite film is placed on the current collector, the overlap phenomenon of the insulating coating layer caused by inevitable process errors as shown in FIGS. 2 and 3 can be prevented, thereby enabling excellent safety and processability.

[0175]

[0176] Hereinafter, the electrode according to the present invention will be described in more detail.

[0177]

[0178] (1) The whole house (10)

[0179] The electrode according to the present invention includes a current collector (10).

[0180]

[0181] When the above electrode is a positive electrode, the current collector (10) may be conductive without causing chemical changes in the battery, and is not particularly limited. For example, the current collector (10) may be stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel with a surface treated with carbon, nickel, titanium, silver, etc.

[0182] The thickness of the current collector (10) may be 8 μm to 500 μm, but is not limited thereto. Additionally, fine irregularities may be formed on the surface of the current collector (10) to increase the adhesion of the electrode composite film (100).

[0183]

[0184] When the above electrode is a negative electrode, the above current collector (10) is not particularly limited as long as it has high conductivity without causing changes in the battery, for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. may be used.

[0185] The above current collector (10) can typically have a thickness of 3 μm to 500 μm, and, as in the case where the above dry electrode is used as an anode, fine irregularities can be formed on the surface of the above current collector (10) to increase the adhesion of the electrode composite film.

[0186]

[0187] According to one embodiment of the present invention, the current collector (10) may include a conductive primer layer between the current collector (10) and the electrode composite film (100). When the above conditions are satisfied, the resistance on the surface of the current collector can be lowered and the adhesion can be improved.

[0188] For example, the conductive primer layer may include a conductive material and a binder, and the conductive material is not limited to any material that exhibits conductivity, but may, for example, be a carbon-based material. The binder may include fluorine-based (including PVDF and PVDF copolymers), acrylic binders, and water-based binders that are soluble in solvents.

[0189]

[0190] According to one embodiment of the present invention, the thickness of the conductive primer layer may be 5 μm or less, preferably 5 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less, 0.01 μm or more, 0.1 μm or more, or 0.2 μm or more, and more preferably 0.2 μm to 1 μm. Satisfying the above range may be desirable in terms of improving adhesion while reducing adverse reactions with the electrolyte and resistance.

[0191]

[0192] (2) Electrode composite film (100)

[0193] A dry electrode according to the present invention comprises an electrode composite film (100) disposed on the current collector (10), wherein the electrode composite film (10) comprises an inclined surface descending from the inner side to the outer side at at least one end portion with respect to the width direction of the electrode composite film (10), and the insulating coating layer (110) is formed to be in contact with a portion of the inclined surface, and the angle of inclination (θ) of the inclined surface s ) is 70° or less.

[0194]

[0195] According to one embodiment of the present invention, the angle of inclination (θ) of the inclined surface s The angle ) may be 70° or less, preferably 65° or less, 60° or less, 50° or less, 45° or less, or 40° or less, and may be 1° or more, 5° or more, 10° or more, 15° or more, 20° or more, or 25° or more, and more preferably 25° to 40°. When the above range is satisfied, an inclined surface having an appropriate angle of inclination can be formed on the electrode composite film (100), thereby preventing an overlap phenomenon when forming an insulating coating layer later, while also preventing a decrease in energy density due to excessive cutting of the electrode composite film (100). For example, the angle of inclination (θ) of the inclined surface s ) may be the angle formed between the inclined surface of the electrode composite film (100) and the current collector (10), as shown in FIG. 13.

[0196]

[0197] According to one embodiment of the present invention, the thickness (L) of the electrode composite film t The thickness may be 20㎛ to 200㎛, preferably 40㎛ to 160㎛, and more preferably 70㎛ to 120㎛. When the above range is satisfied, it may be desirable in that it can achieve excellent energy density and output characteristics while preventing overlap and fat-edge phenomena caused by the insulating coating layer.

[0198]

[0199] According to one embodiment of the present invention, the slope length (L) of the inclined surface s ) and the horizontal length of the inclined surface (L h ) is the angle of inclination (θ) of the above inclined surface s ) and thickness of electrode composite film (L t It can be appropriately controlled depending on ).

[0200]

[0201] According to one embodiment of the present invention, the electrode composite film (100) may include an electrode active material and a binder having a three-dimensional fiber network structure, and preferably, may include an electrode active material, a binder having a three-dimensional fiber network structure and a conductive material.

[0202]

[0203] 1) Electrode active material

[0204] The above electrode composite film may include an electrode active material.

[0205] There are no special limitations on the electrode active material as long as it is a commonly used electrode active material; for example, the electrode active material may be a positive electrode active material or a negative electrode active material.

[0206] The above-mentioned cathode active material is a compound capable of reversible intercalation and deintercalation of lithium, and specifically, may include a lithium metal oxide containing lithium and one or more metals such as cobalt, manganese, nickel, or aluminum. More specifically, the lithium metal oxide is a lithium-manganese-based oxide (e.g., LiMnO2, LiMn2O4, etc.), a lithium-cobalt-based oxide (e.g., LiCoO2, etc.), a lithium-nickel-based oxide (e.g., LiNiO2, etc.), or a lithium-nickel-manganese-based oxide (e.g., LiNi 1-Y Mn Y O2(here, 0 <Y<1), LiMn 2-Z Ni ZO4 (where 0 < Z < 2), etc.), lithium-nickel-cobalt oxides (e.g., LiNi 1-Y1 Co Y1 O2(here, 0 <Y1<1) 등), 리튬-망간-코발트계 산화물(예를 들면, LiCo 1-Y2 Mn Y2 O2(here, 0 <Y2<1), LiMn 2-Z1 Co Z1 O4 (where 0 < Z1 < 2), etc.), lithium-nickel-manganese-cobalt oxides (e.g., Li(Ni p Co q Mn r )O2(where, 0<p<1, 0<q<1, 0<r<1, p+q+r=1) or Li(Ni p1 Co q1 Mn r1 )O4 (where 0<p1<2, 0<q1<2, 0<r1<2, p1+q1+r1=2), etc.), or lithium-nickel-cobalt-transition metal (M) oxide (e.g., Li(Ni p2 Co q2 Mn r2 M s2 )O2(wherein M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg, and Mo, and p2, q2, r2, and s2 are the atomic fractions of independent elements, respectively, 0 < p2 < 1, 0 < q2 < 1, 0 < r2 < 1, 0 < s2 < 1, p2 + q2 + r2 + s2 = 1), etc.), lithium iron phosphate (e.g., Li 1+a Fe 1-x M x (PO 4-b )X b (Here, M is one or more selected from Al, Mg and Ti, and X is one or more selected from F, S and N, and -0.5≤a≤0.5, 0≤x≤0.5, 0≤b≤0.1) etc., and any one or more of these compounds may be included.

[0207] Among these, the lithium metal oxides mentioned above include LiCoO2, LiMnO2, LiNiO2, and lithium nickel manganese cobalt oxide (e.g., Li(Ni)) in that they can improve the capacity characteristics and stability of the battery. 1 / 3 Mn 1 / 3 Co 1 / 3 )O2, Li(Ni 0.6 Mn 0.2 Co 0.2 )O2, Li(Ni) 0.5 Mn 0.3 Co 0.2 )O2, Li(Ni 0.7 Mn 0.15 Co 0.15 )O2 and Li(Ni 0.8 Mn 0.1 Co 0.1 )O2, etc.), lithium nickel-cobalt-aluminum oxide (e.g., Li(Ni 0.8 Co 0.15 Al 0.05 )O2, etc.), or lithium nickel-cobalt-manganese-aluminum oxide (e.g., Li(Ni 0.86 Co 0.05 Mn 0.07 Al 0.02 It may be lithium iron phosphate (e.g., LiFePO4), etc., and any one or more of these may be used. More specifically, the electrode active material may include lithium nickel-cobalt-manganese-aluminum oxide in terms of being able to form a uniform and stable film-shaped electrode composite.

[0208] More preferably, the electrode active material may include a phosphorylated compound represented by the following chemical formula 1.

[0209] [Chemical Formula 1]

[0210] Li 1+x [Fe 1-a-b Mn a M 1 b ]PO4

[0211] In the above chemical formula 1, M 1It contains one or more elements selected from the group consisting of Al, Mg, Ni, Co, Ti, Ga, Cu, V, Mo, Nb, W, Zr, Ce, In, Zn, and Y, and -0.5≤x≤0.5, 0≤a≤0.8, and 0≤b≤0.1. If the above conditions are satisfied, it may be desirable in terms of achieving excellent economic efficiency and stability.

[0212] The above-mentioned negative electrode active material may include at least one selected from the group consisting of lithium metal, a carbon material capable of reversibly intercalating / deintercalating lithium ions, a metal or an alloy of these metals and lithium, a metal composite oxide, a material capable of doping and dedoping lithium, and a transition metal oxide.

[0213] As for the carbon material capable of reversibly intercalating / deintercalating the above lithium ions, any carbon-based negative electrode active material commonly used in lithium-ion secondary batteries may be used without particular limitation, and representative examples include crystalline carbon, amorphous carbon, or a combination thereof. Examples of the above crystalline carbon include graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, and examples of the above amorphous carbon include soft carbon (low-temperature calcined carbon) or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0214] As the above metal or alloy of these metals and lithium, a metal selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn, or an alloy of these metals and lithium may be used.

[0215] The above metal composite oxides include PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, Bi2O5, Li x Fe2O3(0≤x≤1), Li x WO2(0≤x≤1) and Sn x Me 1-x Me y O z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, Group 1, 2, and 3 elements of the periodic table, halogens; 0 <x≤1; 1≤y≤3; 1≤z≤8) 로 이루어진 군에서 선택되는 것이 사용될 수 있다.

[0216] Materials capable of doping and dedoping the above lithium include Si and SiO x (0 <x≤2), Si-Y 합금(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Si은 아님), Sn, SnO2, Sn-Y(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Sn은 아님) 등을 들 수 있고, 또한 이들 중 적어도 하나와 SiO2를 혼합하여 사용할 수도 있다. 상기 원소 Y로는 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ge, P, As, Sb, Bi, S, Se, Te, Po 및 이들의 조합으로 이루어진 군에서 선택될 수 있다.

[0217] Examples of the above transition metal oxides include lithium-containing titanium composite oxide (LTO), vanadium oxide, and lithium vanadium oxide.

[0218]

[0219] According to one embodiment of the present invention, the average particle size of the electrode active material may be 0.1 μm to 5.0 μm, preferably 0.2 μm to 2.5 μm, and more preferably 0.3 μm to 2.0 μm. When the above range is satisfied, film formation may be easy when manufacturing a powder sheeting film and / or an electrode composite film, and excellent capacity and output characteristics can be realized.

[0220]

[0221] According to one embodiment of the present invention, D of the electrode active material v10 The thickness may be 0.01㎛ to 1.50㎛, and preferably, D of the electrode active material v10 The thickness may be 0.05㎛ to 1.00㎛, and more preferably, D of the electrode active material v10 The thickness may be 0.2㎛ to 0.8㎛. When the above range is satisfied, film formation may be easy when manufacturing powder-sheeting films and / or electrode composite films, and excellent capacitance and output characteristics can be realized.

[0222]

[0223] According to one embodiment of the present invention, a coating layer comprising carbon (C) may be further included, formed on the electrode active material. When the above conditions are satisfied, ion conductivity and electron conductivity can be improved.

[0224]

[0225] According to one embodiment of the present invention, the electrode active material may be included in an amount of 80 to 99 parts by weight based on the total weight of the electrode composite film, and preferably in an amount of 90 to 99 parts by weight. Satisfying the above range is desirable in terms of increasing the capacity and energy density of the electrode.

[0226]

[0227] 2) Binder

[0228] The electrode composite film may include a binder having a three-dimensional fiber network structure. In one aspect, the binder functions to form a three-dimensional fiber network structure so that the electrode composite film can stand on its own. The binder is not specified as being capable of fiberization, that is, if it can form a three-dimensional fiber network structure within the electrode composite film through fiberization and provide a void capable of accommodating an electrode active material and, optionally, a conductive material.

[0229] The fiberization of the above binder refers to a treatment that divides the polymer applied as a binder into smaller fibers, which can be performed, for example, by applying mechanical shear force, and as a result, the surface is loosened and fiberized, forming multiple microfibers, and thereby can include a three-dimensional fiber network structure.

[0230]

[0231] The fiberizable binder may preferably include one or more selected from the group consisting of polytetrafluoroethylene (PTFE) and polyolefins, more preferably may include polytetrafluoroethylene, and even more preferably may be polytetrafluoroethylene.

[0232] At this time, the binder may additionally include one or more selected from the group consisting of polyethylene oxide (PEO), polyvinylidene fluoride (PVdF), polyvinylidene fluoride-cohexafluoropropylene (PVdF-HFP), polyacrylic acid (PAA), polyvinylpyrrolidone (PVP), and polyolefin. Preferably, it may further include high-density polyethylene. When two or more types of the binder are mixed, the polytetrafluoroethylene may be included in an amount of 60% by weight or more based on the total weight of the binder.

[0233]

[0234] According to one embodiment of the present invention, the binder may be included in an amount of 0.1 to 10 parts by weight with respect to the total weight of the electrode composite film, and preferably in an amount of 0.1 to 5.0 parts by weight. Satisfying the above range is desirable in that it can achieve a degree of fiberization suitable for manufacturing a self-standing sheet while also having excellent resistance characteristics.

[0235]

[0236] 3) Challenge material

[0237] The above electrode composite film may include a conductive material.

[0238] The above conductive material is a component for further improving the conductivity of the electrode active material, and such conductive material is not particularly limited as long as it is conductive without causing chemical changes in the battery, and for example, carbon powder such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, or thermal black; graphite powder such as natural graphite, artificial graphite, or graphite with a highly developed crystal structure; conductive fibers such as carbon fibers or metal fibers; fluorocarbon powder; conductive powder such as aluminum powder or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives, etc. may be used. In detail, to ensure uniform mixing of the conductive material and to improve conductivity, it may include one or more selected from the group consisting of activated carbon, graphite, carbon black, and carbon nanotubes (CNT).

[0239]

[0240] According to one embodiment of the present invention, the conductive material may be included in an amount of 0.1 to 10 parts by weight with respect to the total weight of the electrode composite film, and preferably in an amount of 0.1 to 5.0 parts by weight. Satisfying the above range is desirable in that it can form an excellent conductive path while also realizing an excellent capacity density.

[0241]

[0242] (3) Insulating coating layer (110)

[0243] The dry electrode according to the present invention comprises an insulating coating layer (110) disposed on the current collector (10), and the insulating coating layer (110) is formed to be in contact with a portion of the inclined surface. Preferably, the insulating coating layer (110) is formed to be in contact with a portion of the current collector (10) while being in contact with a portion of the inclined surface.

[0244] The above insulating coating layer (110) is coated on an uncoated portion near the end of the current collector to prevent a short circuit caused by contact between the positive and negative electrodes.

[0245] For example, the insulating coating layer (110) may be capable of being coated on the current collector (10) and the inclined surface while ensuring insulating performance, and its material or composition is not particularly limited. The insulating coating layer (110) may be a viscous composition containing an insulating material.

[0246]

[0247] According to one embodiment of the present invention, the insulating coating layer (110) may include an insulating material, and may include one or more selected from the group consisting of, for example, boehmite, tannic acid, styrene butadiene rubber (SBR), polyethylene terephthalate (PET), polyimide (PI), and polypropylene (PP). When the above conditions are satisfied, excellent insulating properties can be achieved.

[0248]

[0249] According to one embodiment of the present invention, the width of the insulating coating layer (110) may be 1 mm to 8 mm, preferably 2 mm to 6 mm, and more preferably 3 mm to 5 mm. Satisfying the above range may be desirable in that excellent insulation properties can be achieved by forming an insulating coating layer of appropriate width while preventing the overlap phenomenon. For example, the width of the insulating coating layer (110) is the horizontal length (L) of the aforementioned inclined surface. h It can mean the length on the same line as ).

[0250]

[0251] According to one embodiment of the present invention, the thickness of the insulating coating layer (110) may be 20 μm or less, preferably 0.5 μm to 10 μm, and more preferably 0.5 μm to 5.0 μm. Satisfying the above range may be desirable in that excellent insulation properties can be realized by forming an insulating coating layer of appropriate width while preventing the overlap phenomenon. For example, the thickness of the insulating coating layer (110) is the thickness (L) of the aforementioned electrode composite film. t It may mean a length along the same line as ), and with respect to one surface where the insulating coating layer (110) is in contact with the current collector (10), it may mean the maximum height of the insulating coating layer (100) vertically from said surface.

[0252]

[0253] According to one embodiment of the present invention, the maximum height of the insulating coating layer (110) may be less than the maximum height of the electrode composite film (100). When the above condition is satisfied, the insulating coating layer is not placed on the upper surface of the electrode composite film due to process errors that inevitably occur, thereby preventing the fat-edge phenomenon in which only a portion of the thickness of one side of the electrode composite film becomes thicker, and it is desirable in that it prevents defects such as pressing or tearing of the current collector, detachment of the electrode composite film and / or insulating coating layer, and damage to the current collector during rolling.

[0254]

[0255] According to one embodiment of the present invention, the electrode may be in a jumbo-roll form. For example, the jumbo-roll form may be a form in which the electrode is stored during a roll-to-roll process to manufacture a large quantity of dry electrodes in a short period of time. When the above conditions are satisfied, the electrode according to the present invention does not exhibit a fat-edge phenomenon, so it may be desirable in that defects such as compression or tearing of the current collector and damage to the current collector can be prevented even when stored in a jumbo-roll form.

[0256]

[0257] secondary battery

[0258] Hereinafter, a secondary battery according to the present invention will be described.

[0259]

[0260] A secondary battery according to one embodiment of the present invention may include a dry electrode as described above. For example, the secondary battery may include a secondary battery including a liquid electrolyte and an all-solid-state battery including a solid electrolyte.

[0261]

[0262] A lithium secondary battery according to the present invention may include an electrode according to the present invention. More specifically, it may include a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the positive electrode and / or the negative electrode may be a dry electrode, and specifically, the lithium secondary battery may include an electrode, a negative electrode, a separator, and an electrolyte according to the present invention. If only one of the positive electrode or the negative electrode is a dry electrode according to the present invention, the other electrode may be an electrode manufactured through a conventional wet manufacturing method.

[0263]

[0264] In the case where a secondary battery according to one embodiment of the present invention is a secondary battery comprising a liquid electrolyte, a separator may be included between a plurality of electrodes. The separator separates the negative electrode and the positive electrode and provides a pathway for the movement of lithium ions. Any separator typically used as a separator in a secondary battery may be used without special limitations, and it is particularly desirable that it has low resistance to the movement of electrolyte ions and excellent electrolyte moisture retention capacity. Specifically, a porous polymer film, such as a porous polymer film made of a polyolefin-based polymer like an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof may be used. In addition, a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fibers or polyethylene terephthalate fibers, may be used. In addition, a coated separator containing ceramic components or polymer materials may be used to ensure heat resistance or mechanical strength, and may optionally be used in a single-layer or multi-layer structure.

[0265] In addition, if the secondary battery is an all-solid-state battery, the solid electrolyte membrane can be manufactured to perform the function of the separator.

[0266]

[0267] The above separator separates the negative electrode and the positive electrode and provides a pathway for the movement of lithium ions. It can be used without special limitations as long as it is typically used as a separator in a lithium secondary battery, and it is particularly desirable that it has low resistance to the movement of electrolyte ions and excellent electrolyte wettability. Specifically, a porous polymer film, such as a porous polymer film made of a polyolefin-based polymer like ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof may be used. In addition, a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fiber or polyethylene terephthalate fiber, may be used. Furthermore, a coated separator containing ceramic components or polymer materials may be used to ensure heat resistance or mechanical strength, and it may optionally be used in a single-layer or multi-layer structure.

[0268]

[0269] In addition, the above electrolyte may be selected from organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, molten inorganic electrolytes, etc., which are usable when manufacturing secondary batteries, but is not limited to these.

[0270] Specifically, the electrolyte may include an organic solvent and a lithium salt. The organic solvent may be used without special limitations as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the organic solvent may include ester-based solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether-based solvents such as dibutyl ether or tetrahydrofuran; ketone-based solvents such as cyclohexanone; and aromatic hydrocarbon-based solvents such as benzene and fluorobenzene. Carbonate-based solvents such as dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol-based solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (where R is a straight-chain, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double bond, a directional ring, or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes may be used. Among these, a carbonate-based solvent is preferred, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate, etc.) having high ionic conductivity and high dielectric constant that can improve the charge / discharge performance of the battery, and a low-viscosity linear carbonate-based compound (e.g., ethylmethyl carbonate, dimethyl carbonate or diethyl carbonate, etc.) is more preferred.

[0271]

[0272] The above lithium salt may be used without special restrictions as long as it is a compound capable of providing lithium ions used in secondary batteries. Specifically, the anion of the above lithium salt is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - It may be at least one selected from the group consisting of, and the lithium salt is, LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAlO4, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2) 2. LiCl, LiI, or LiB(C2O4)2, etc. may be used. It is preferable to use the lithium salt within a concentration range of 0.1M to 4.0M, preferably 0.5M to 3.0M, and more preferably 1.0M to 2.0M. When the concentration of the lithium salt falls within the above range, the electrolyte has appropriate conductivity and viscosity, so it can exhibit excellent electrolyte performance and lithium ions can move effectively.

[0273]

[0274] In addition to the above electrolyte components, the above electrolyte may further include one or more additives for the purpose of improving the lifespan characteristics of the battery, suppressing the decrease in battery capacity, and improving the discharge capacity of the battery, such as, for example, haloalkylene carbonate-based compounds like difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, triamide hexaphosphate, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, or aluminum trichloride. In this case, the additive may be included in an amount of 0.1 to 10.0 weight% based on the total weight of the electrolyte.

[0275]

[0276] battery box

[0277] In another aspect, a battery box comprising a plurality of the above secondary batteries may be provided. The battery box may include a plurality of secondary batteries and may include a packaging that accommodates the plurality of secondary batteries. Here, the battery box may be, for example, a battery module or a battery pack.

[0278] Since the above secondary battery stably exhibits excellent discharge capacity, output characteristics, and capacity retention rate, it can be usefully applied in portable devices such as mobile phones, laptops, and digital cameras, or in the field of electric vehicles such as Full Electric Vehicles (FEVs) and Hybrid Electric Vehicles (HEVs).

[0279] The above battery box may be used as one or more power devices selected from the group consisting of a power tool; an electric vehicle including a full electric vehicle (FEV), a hybrid electric vehicle (HEV), and a plug-in hybrid electric vehicle (PHEV); or a power storage system.

[0280]

[0281] According to the present specification, in another aspect, an electric device or electronic device may be provided that includes the battery box, wherein the battery box is included as a power source.

[0282]

[0283]

[0284] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0285]

[0286] Examples and Comparative Examples

[0287] Preparation Example: Preparation of powder for electrodes

[0288] Lithium iron phosphate (LFP, D) as an electrode active material v10 935g of (0.38㎛), 15g of Ketjen black as a conductive material, and 50g of polytetrafluoroethylene (PTFE) as a fiberizable binder were put into a blender and mixed at 1500rpm for 10 minutes to prepare each composite composition.

[0289] After that, the above composite composition was fed into a kneader and mixed by kneading at a rotational speed of 50 rpm for 10 minutes at a temperature of 150°C and 1.1 atm to produce a mixed aggregate, and the mixed aggregate was coarsely ground using a cut-mill until the average particle size was 2 mm, and then finely ground using a pin-mill at a rotational speed of 5000 rpm until the average particle size was 400 μm to produce the electrode powder of the preparation example.

[0290]

[0291] Example 1: Preparation of a dry electrode

[0292] After producing an electrode composite film by sheeting the above electrode powder onto a rolling roll in a roll-to-roll process and rolling it, inclined surfaces descending outwardly were formed at both ends of the electrode composite film relative to its width using a first rolling roll including a shear knife cutting device. Subsequently, the electrode composite film was produced by heat pressing through the first and second rolling rolls. At this time, the bevel of the shear knife blade was oriented toward the inner side of the electrode composite film.

[0293] Afterwards, the electrode composite film and the current collector (aluminum foil, thickness: 15㎛) having a conductive primer layer formed thereon were fed into a lamination section including the second rolling roll and the third rolling roll to perform lamination.

[0294] After that, an insulating liquid was discharged onto a current collector adjacent to each of the aforementioned inclined surfaces, and then dried to manufacture a dry electrode.

[0295] At this time, the characteristics of the electrode composite film were as shown in Table 2 below.

[0296]

[0297] Example 2: Preparation of a dry electrode

[0298] A dry electrode was manufactured in the same manner as in Example 1, except that a first rolling roll including a score knife cutting device having beveled sides on both sides of the blade was used instead of a shear knife.

[0299] At this time, the characteristics of the electrode composite film were as shown in Table 2 below.

[0300]

[0301] Comparative Example 1: Preparation of a dry electrode

[0302] A dry electrode was manufactured in the same manner as in Example 1, except that the cutting device was included in the second rolling roll instead of the first rolling roll, and the bevel of the shear knife blade was set to face outward from the electrode composite film to cut the electrode composite film vertically.

[0303] At this time, the characteristics of the electrode composite film were as shown in Table 2 below.

[0304]

[0305] Comparative Example 2: Preparation of a dry electrode

[0306] A dry electrode was manufactured in the same manner as in Example 1, except that the cutting device was included in the second rolling roll instead of the first rolling roll, and a score knife cutting device having beveled sides on both sides of the blade was used instead of a shear knife.

[0307] At this time, in the case of the electrode composite film, an inclined surface was formed rising from the inner side of the electrode composite film toward the outer side of the current collector.

[0308]

[0309] The above manufacturing method was summarized and shown in Table 1 below, and the characteristics of the electrode composite film were as shown in Table 2 below.

[0310]

[0311] Cutting device Knife type Blade hypotenuse direction Angle (°) formed between the inclined plane and the horizontal plane of the first or second rolling roll containing the cutting device Example 1: First rolling roll shear knife, inner side of film 60 Example 2: First rolling roll score knife -60 Comparative Example 1: Second rolling roll shear knife, outer side of film 90 Comparative Example 2: Second rolling roll score knife -30

[0312] Horizontal length (L) of the inclined surface of the electrode composite film h , μm) Inclined length of the inclined surface (Ls, μm) Thickness (L t , μm) Inclination angle (°) Example 1 206 231 105 27 Example 2 225 248 105 25 Comparative Example 10-105 90 Comparative Example 26 31 221 05 121

[0313] Experimental Example 1: Evaluation of Fat-edge Occurrence

[0314] The appearance of the dry electrodes prepared in Examples 1 and 2 and Comparative Examples 1 and 2 was checked, and if the insulating coating layer was positioned higher than the maximum height of the electrode composite film, it was evaluated as X, and if it was positioned lower than the maximum height of the electrode composite film, it was evaluated as O.

[0315] The evaluation results are shown in Table 3 below.

[0316]

[0317] Whether fat-edge occurs Example 10 Example 20 Comparative Example 1X Comparative Example 2X

[0318] Referring to Table 3 above, it can be seen that in the case of Examples 1 and 2, in which a dry electrode is manufactured using a cutting device that satisfies specific conditions in a specific rolling roll, or in which a descending inclined surface is included and the angle of inclination of the inclined surface satisfies the aforementioned range, no fat edge occurs, unlike in Comparative Examples 1 and 2, which do not.

[0319]

[0320] [Explanation of the symbol]

[0321] 10: The whole house

[0322] 100: Electrode composite film

[0323] 110: Insulating coating layer

[0324] 301: 1st Rolling Roll

[0325] 302: Second rolling roll

[0326] 303: Third rolling roll

[0327] 401: Cutting device

[0328] 402: Sheer Knife

[0329] 403: Score Knife

[0330] L h : Horizontal length of the inclined plane

[0331] L t : Thickness of the electrode composite film

[0332] L s : Slope length of the inclined plane

[0333] Θ s : Angle of inclination

Claims

1. Step S1 of forming an inclined surface descending from the inner side to the outer side at at least one end portion with respect to the width direction of the electrode composite film through a first rolling roll including a cutting device; Step S2 of heat-pressing the electrode composite film using the first rolling roll and the second rolling roll; Step S3, in which the electrode composite film and the current collector are fed into a lamination unit including a second rolling roll and a third rolling roll to perform lamination; and A method for manufacturing an electrode, comprising: a step S4 of coating an insulating liquid on a current collector so as to be adjacent to the inclined surface based on the width direction of the current collector.

2. In Claim 1, A method for manufacturing an electrode, wherein the cutting device comprises one or more types selected from the group consisting of a shear knife and a score knife.

3. In Claim 1, A method for manufacturing an electrode, wherein the angle formed between the inclined surface and the horizontal plane of the first rolling roll is 80° or less.

4. In Claim 1, A method for manufacturing an electrode, wherein the angle formed between the inclined surface and the horizontal plane of the first rolling roll is 30° to 45°.

5. In Claim 1, A method for manufacturing an electrode, wherein the peripheral speed ratio of the second rolling roll to the first rolling roll is 1.01 to 1.

20.

6. In Claim 1, A method for manufacturing an electrode, wherein the thickness of the insulating liquid is 20㎛ or less.

7. In Claim 1, A method for manufacturing an electrode, further comprising the step S5 of drying the insulating solution.

8. In Claim 1, A method for manufacturing an electrode, wherein the above electrode composite film is manufactured by a method comprising the following steps A1 to A4: (A1) A step of forming a composite composition by mixing an electrode active material and a fiberizable binder; (A2) A step of forming a mixed aggregate by kneading the above composite composition while applying shear force; (A3) A step of grinding the above-mentioned mixed aggregate to produce a powder for electrodes; and (A4) A step of manufacturing a powder sheeting film by sheeting the above electrode powder.

9. A current collector; an electrode composite film disposed on the current collector; and an insulating coating layer disposed on the current collector; comprising, The electrode composite film includes an inclined surface descending from the inner side to the outer side at at least one end portion based on the width direction of the electrode composite film, The above insulating coating layer is formed so that a portion of it contacts the inclined surface, and An electrode in which the angle of inclination of the above inclined surface is 70° or less.

10. In Claim 9, An electrode in which the angle of inclination of the above inclined surface is 25° to 40°.

11. In Claim 9, The electrode, wherein the thickness of the electrode composite film is 20㎛ to 200㎛.

12. In Claim 9, An electrode having an insulating coating layer with a width of 1 mm to 8 mm.

13. In Claim 9, An electrode having an insulating coating layer with a thickness of 20㎛ or less.

14. In Claim 9, An electrode in which the maximum height of the insulating coating layer is less than the maximum height of the electrode composite film.

15. A secondary battery comprising the electrode of claim 9.

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