Electrode manufacturing system, electrode manufacturing method, and electrode

Abstract

An electrode manufacturing system according to an exemplary embodiment of the present invention comprises: a coating unit composed of a first coating unit for applying an electrode slurry to a first surface of a current collector and a second coating unit for applying the electrode slurry to a second surface of the current collector; an air spraying unit; and a drying unit, wherein the air spraying unit is disposed on a transfer path between the second coating unit and the drying unit. The formation of a fat-edge in a second electrode active material layer due to a sliding region of a first electrode active material layer formed on the first surface of the current collector can be prevented by spraying the fat-edge with air and thereby moving the electrode toward an uncoated portion.

Description

Electrode manufacturing system, electrode manufacturing method and electrode

[0001] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2023-0128329, filed on September 25, 2023.

[0002] The present invention relates to a double-sided electrode having a structure in which electrode active material layers are laminated on both sides of a current collector, in which the occurrence of a fat edge is prevented, a manufacturing system for such an electrode, and a manufacturing method for the electrode.

[0003]

[0004] As technological development and demand for industrial fields such as mobile devices, automobiles, and energy storage devices increase, the demand for batteries as an energy source is rapidly increasing. Among these secondary batteries, lithium secondary batteries with high energy density and discharge voltage have been studied extensively and are now commercialized and widely used.

[0005] Secondary batteries are classified into cylindrical and prismatic batteries, in which the electrode assembly is built into a cylindrical or prismatic metal can, and pouch-type batteries, in which the electrode assembly is built into a pouch-type case made of aluminum laminate sheet, depending on the shape of the battery case.

[0006] In addition, the electrode assembly built into the battery case is a power plant capable of charging and discharging, which is composed of a stacked structure of anode / separator / cathode, and includes a jelly-roll type electrode assembly in which a long sheet-shaped cathode and cathode on which an electrode mixture including an electrode active material is applied are wound with a separator interposed between them, a stack type (laminated type) electrode assembly in which a plurality of cathodes and anodes punched and notched in units of a predetermined size are sequentially stacked with a separator interposed between them, and a stack / folding type electrode assembly in which bi-cells or full cells are wound with a structure in which anodes and cathodes in predetermined units are stacked with a separator interposed between them.

[0007] The positive and negative electrodes that make up the electrode assembly are manufactured by applying the electrode slurry manufactured in the mixing process to the electrode current collector through a slot die in a set pattern and at a constant thickness, and then drying it. In this electrode process, for various reasons, the thickness of the electrode active material layer at both sides of the transverse direction (TD) of the electrode may form a thicker fat edge compared to the surrounding electrode active material layers. If such a fat edge exists in the electrode, the current collector may be damaged during the rolling process, which may cause a safety issue. In addition, the fat edge may damage other electrodes or separators during the process of stacking multiple positive / negative electrodes and separators. In particular, if the positive electrode has a high capacity compared to the negative electrode, lithium may precipitate, and the fat edge may cause a reversal of the NP-Ratio of the positive / negative electrode, which may also cause a safety issue in the battery.

[0008] In order to prevent the occurrence of such PET-edge, there is a method of readjusting the transverse (Y-axis direction) spreading width of the electrode slurry, the distance between the slot die and the current collector, and the temperature of the electrode slurry in the coating step. However, when this is applied to a mass production process, there is the inconvenience of having to reset the above conditions to optimized conditions in the coating step, and even if the above conditions are optimized, if problems such as changes in the electrode slurry over time occur, the spreading characteristics of the slurry change, and accordingly, the continuous process must be temporarily stopped and the conditions optimized again.

[0009] Therefore, there is a need for technological development of a manufacturing system and manufacturing method for electrodes to prevent the occurrence of PET edges without stopping the electrode process.

[0010]

[0011] The technical idea of ​​the present invention is to provide an electrode, a manufacturing system for the electrode, and a manufacturing method for the electrode, which prevents the occurrence of a fat edge in a double-sided electrode having a structure in which electrode active material layers are laminated on both sides of a current collector.

[0012]

[0013] According to one embodiment of the present invention, a system for manufacturing an electrode is provided. The system for manufacturing an electrode includes a slot die configured to discharge electrode slurry; and a coating roller disposed spaced apart from the slot die and configured to support a current collector; an air spraying unit configured to spray air toward a periphery of a boundary between a holding portion and a non-coating portion of an electrode taken out from the coating unit; and a drying unit for drying the electrode slurry; wherein the coating unit includes a first coating unit for applying electrode slurry to a first surface of the current collector and a second coating unit for applying electrode slurry to a second surface of the current collector, and the air spraying unit may be disposed on a transport path between the second coating unit and the drying unit.

[0014] In a manufacturing system for an electrode according to one embodiment, the electrode may be configured to be transported sequentially through the first coating unit, the drying unit, the second coating unit, the air injection unit, and the drying unit.

[0015] In a manufacturing system for an electrode according to one embodiment, the air injection unit may be configured to inject air in a direction inclined with respect to an imaginary extension line of a flat surface of the maintenance unit.

[0016] In a manufacturing system for an electrode according to one embodiment, the air injection unit may be configured to enable angle adjustment of the air injection direction.

[0017] A system for manufacturing an electrode according to one embodiment may further include a measuring unit configured to measure a coating amount of electrode slurry applied to a holding unit; and an air spray controller configured to adjust an air spray angle, an air spray position, and an air spray intensity based on the coating amount received from the measuring unit.

[0018] In a manufacturing system for an electrode according to one embodiment, the measuring unit may be configured to calculate the coating amount of the electrode slurry in real time based on an X-ray absorption method.

[0019] In a manufacturing system for an electrode according to one embodiment, the measuring unit may be configured to calculate a coating amount of the electrode slurry in real time based on a measured distance from a measuring position to the holding unit.

[0020] In a manufacturing system for an electrode according to one embodiment, the measuring unit may be disposed downstream of a slot die of the second coating unit.

[0021] In a manufacturing system for an electrode according to one embodiment, the measuring unit may be configured to measure a vicinity of a boundary between the holding unit and the non-holding unit.

[0022] In a manufacturing system for an electrode according to one embodiment, the slot die may include two or more die blocks; and a shim plate interposed between the die blocks to form a slot.

[0023] According to another embodiment of the present invention, a method for manufacturing an electrode is provided. The method for manufacturing an electrode may include: a first coating step of applying electrode slurry to a first surface of a transported current collector; a first drying step of drying the electrode slurry applied to the first surface; a second coating step of applying electrode slurry to a second surface of the transported current collector; a step of measuring a coating amount of electrode slurry near a boundary between a holding portion and a non-coating portion; a step of determining whether a PET edge exists based on the measured coating amount; a step of spraying air to the PET edge to remove the PET edge when it is determined that a PET edge exists; and a second drying step of drying the electrode slurry applied to the second surface.

[0024] In a method for manufacturing an electrode according to one embodiment, the electrode slurry may be a cathode slurry.

[0025] According to another embodiment of the present invention, an electrode for a secondary battery is provided. The electrode comprises: a current collector; and first and second electrode active material layers formed on one surface and the other surface of the current collector, respectively, wherein the first and second electrode active material layers include first and second sliding regions inclined with respect to a plane of the current collector, respectively, and when the second electrode active material layer and the first electrode active material layer rotated by 180° are overlapped, the inclined surface of the second sliding region may have a concave portion having an indented shape with respect to the inclined surface of the first sliding region.

[0026] The above electrode may be an anode.

[0027]

[0028] According to exemplary embodiments of the present invention, a double-sided electrode without a fat edge is provided by spraying air onto the fat edge of the second electrode active material layer caused by the sliding area of ​​the first electrode active material layer formed on the first surface of the current collector to move the electrode slurry toward the non-fat region.

[0029] In addition, according to an exemplary embodiment of the present invention, since an air injection unit configured to inject air toward the periphery of the boundary between the electrode holding portion and the electrode non-stick portion is simply installed in a conventional electrode processing line, an electrode without a PET edge can be manufactured in a relatively easy manner, and since the continuous seeding electrode process does not have to be stopped, there is an advantage in that production efficiency is not reduced.

[0030]

[0031] Figure 1 is a drawing showing a method for manufacturing a double-sided electrode according to a conventional technique.

[0032] Figure 2 is a cross-sectional view of an electrode having a pet-edge.

[0033] Figure 3 is a drawing showing the results of measuring the thickness of the electrode active material layer located inside the dotted line in Figure 2.

[0034] Figure 4 is a schematic diagram of a double-sided electrode manufacturing system according to exemplary embodiments.

[0035] FIG. 5 is a schematic diagram of a double-sided electrode manufacturing system according to exemplary embodiments.

[0036] Figure 6 is an exploded perspective view of a slot die according to exemplary embodiments.

[0037] Figure 7 is a schematic diagram of an air injection unit according to exemplary embodiments of the present invention.

[0038] Figure 8 is a flowchart illustrating a method for manufacturing a double-sided electrode according to exemplary embodiments.

[0039] Figure 9 is a cross-sectional view of an electrode according to exemplary embodiments.

[0040]

[0041] [Explanation of symbols]

[0042] 10,20: Electrode

[0043] 11,21: Whole house

[0044] 12,22: First electrode active material layer

[0045] 13,23: Second electrode active material layer

[0046] 100: Electrode manufacturing system

[0047] 110: First coating section

[0048] 110': Second coating section

[0049] 120: Air injection part

[0050] 130: Drying section

[0051]

[0052] Hereinafter, the present invention will be described in more detail to help understand the present invention.

[0053] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0054] The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

[0055] In this specification, it should be understood that the terms “include,” “comprising,” or “having” are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0056] In this specification, the term "combination(s) thereof" included in the surface of the Makushi format means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Makushi format, and means including one or more selected from the group consisting of the above components.

[0057] In this specification, the description of “A and / or B” means “A or B or both.”

[0058] In this specification, “%” means weight percent unless explicitly indicated otherwise.

[0059] In this specification, the transverse direction (TD) of the current collector and electrode is defined as the Y-axis direction, the transport direction (MD) of the current collector and electrode is defined as the X-axis direction, the thickness direction of the electrode is defined as the Z-axis direction, and the X-axis direction and the Y-axis direction are referred to as horizontal directions.

[0060] In this specification, the maintenance portion is defined as a portion of the electrode substrate where electrode slurry is applied, and the uncoated portion is defined as a portion of the electrode substrate where electrode slurry is not applied and the current collector is exposed.

[0061]

[0062] (Example 1)

[0063] The present invention provides a system for manufacturing an electrode as a first embodiment.

[0064] FIG. 4 is a schematic diagram of an electrode manufacturing system according to exemplary embodiments, and FIG. 5 is a schematic diagram of an electrode manufacturing system according to exemplary embodiments.

[0065] Referring to these drawings, the electrode manufacturing system according to exemplary embodiments may include a coating unit (110, 110'), an air injection unit (120), and a drying unit (130, 130'), and the coating unit may be composed of a first coating unit (110) and a second coating unit (110'), and the air injection unit (120) may be disposed on a transport path between the second coating unit (110') and the drying unit (130'). That is, the air injection unit (120) is disposed on a transport path between the second coating unit (110') and the drying unit (130'), but is not disposed on a transport path between the first coating unit (110) and the drying unit (130). The electrode manufacturing system is a system that applies electrode slurry to a current collector (21) being transported in a roll-to-roll manner and dries it to manufacture an electrode.

[0066] The inventors of the present invention have conducted extensive research into the cause of PET-edge formation during the manufacture of double-sided electrodes, and have discovered that PET-edge mainly occurs in the electrode active material layer on the back surface of the current collector, leading to the present invention.

[0067] Fig. 1 is a drawing showing a method for manufacturing a double-sided electrode according to a conventional technique, Fig. 2 is a cross-sectional view of a double-sided electrode manufactured according to a conventional technique and having a PET edge, and Fig. 3 is a drawing showing the results of measuring the thickness of an electrode active material layer located inside the dotted line in Fig. 2.

[0068] According to a conventional double-sided electrode manufacturing method, a first electrode active material layer (12) is formed through a first coating step of applying electrode slurry to the first surface of a current collector (11), and then a second coating step of applying electrode slurry to the second surface of the current collector (11) is performed.

[0069] Referring to FIG. 1, the transverse (Y-axis direction) edges of the first electrode active material layer (12) formed in the first coating step include a sliding region (12S) in which the end surface of the first electrode active material layer (12) is inclined with respect to the plane of the current collector (11). The first electrode active material layer (12) including the sliding region faces the coating roller (112') in the second coating step, and since the sliding region (12S) has a smaller thickness than a portion that is not the sliding region, the transverse (Y-axis direction) edge portion of the current collector (11) that contacts the coating roller (112') has a slightly bent shape following the inclination angle of the sliding region, as illustrated in FIG. 1. In this state, when electrode slurry is applied to the second surface of the current collector (11), the coating amount of the electrode slurry applied near the point (arrow) where the current collector (11) begins to bend slightly downward may be greater than the coating amount of the electrode slurry applied to a flat area of ​​the current collector (11) parallel to the horizontal direction (Y-axis direction). Accordingly, the second electrode active material layer (13) of the relevant area includes a pet-edge having a shape that protrudes upward in the thickness direction (Z-axis direction) compared to the surrounding second electrode active material layers (see FIGS. 2 and 3).

[0070] As described above, since the thickness of the sliding region (12S) of the first electrode active material layer (12) formed on the first surface of the current collector (11) is relatively small compared to the flat portion, the current collector (11) of the electrode is slightly bent downwards in the second coating step to follow the shape of the sliding region (12S) of the first electrode active material layer (12). When the electrode slurry is applied while the current collector (11) is bent downwards, the electrode surface is flat, but a PET-edge is created in which the thickness of the electrode slurry applied is thicker than the flattened region based on the current collector plane.

[0071] According to an exemplary embodiment of the present invention, the air injection unit (120) is configured to inject air toward the sliding area, specifically, the pet-edge, of the electrode (20) taken out from the second coating unit (110'), so that the electrode slurry at the area where the air is injected moves toward the periphery by the air injection pressure, thereby reducing the coating thickness of the electrode slurry at the area. Accordingly, the pet-edge is prevented from occurring at the edges on both sides of the transverse direction (Y-axis direction) of the second electrode active material layer (23).

[0072] The above coating unit (110, 110') may be configured to discharge electrode slurry onto a current collector (21) that is transported in one direction. The coating unit (110, 110') applies electrode slurry onto the current collector (21) to have a predetermined width and thickness, and the electrode slurry applied in this way becomes an electrode active material layer (12) via a drying unit (130, 130').

[0073] The above electrode slurry may be a mixture of an electrode active material, a binder, a conductive agent, and a solvent, and the electrode active material may be a positive electrode active material or a negative electrode active material. The binder may be a polymer additive for structural stabilization of the electrode, and the conductive agent may be a carbon-based additive having electrical conductivity.

[0074] The above coating unit (110, 110') may include a slot die (111, 111') configured to discharge electrode slurry; and a coating roller (112, 112') disposed spaced apart from the slot die and for supporting a current collector sheet.

[0075] Fig. 6 is an exploded perspective view of a slot die according to exemplary embodiments. Referring to Fig. 6, the slot die (111) may include two die blocks (111a, 111b); and a shim plate (111c). The shim plate (111c) may be interposed between the two die blocks (111a, 111b), which may be fastened to each other by a plurality of bolt members. At least one of the two die blocks may be provided with a manifold (111d) for accommodating a certain volume of electrode slurry, and the manifold (111d) may be connected to an external electrode slurry supply unit (not shown).

[0076] Although Fig. 6 illustrates a slot die having two die blocks, the number of die blocks is not limited thereto and may be two or more. Specifically, two die blocks may be required to apply a single electrode slurry, and three or more die blocks may be required to apply two or more electrode slurries. In other words, there may be two or more die blocks.

[0077] The above coating roller (112, 112') may be configured to support the current collector (21) and transport it in the transport direction when the electrode slurry is discharged from the slot die (111, 111'). The coating roller (112, 112') may be spaced apart from the current collector (21) at the bottom of the slot die (111, 111').

[0078] The above coating portion (110, 110') may be composed of a first coating portion (110) that applies electrode slurry to the first surface of the current collector (21) and a second coating portion (110') that applies electrode slurry to the second surface of the current collector (21) to manufacture a double-sided electrode having a structure in which electrode active material layers are laminated on both surfaces of the current collector (21). The second coating portion (110') differs from the first coating portion (110) only in the installation position, and the type and application method of the electrode slurry applied to the current collector (21) are the same.

[0079] The above drying unit is configured to apply heat energy to the electrode slurry applied on the current collector (21) to dry the electrode slurry. The drying unit (130) may be configured with a first drying unit (130) that dries the electrode slurry applied on the first surface of the current collector (21) and a second drying unit (130') that dries the electrode slurry applied on the second surface of the current collector (21) to dry a double-sided electrode having a structure in which electrode active material layers are laminated on both surfaces of the current collector (21). The second drying unit (130') may be the same as the first drying unit (130) in terms of its installation location, but its drying method may be the same.

[0080] The above drying unit (130, 130') may include a drying means, and the drying means may include a hot air supply unit configured to spray hot air toward the electrode slurry applied on the current collector (21) and / or a heater configured to irradiate radiant heat. The current collector on which the electrode slurry is applied passes through the drying unit (130, 130'), and the electrode is dried by the heat energy applied by the drying means.

[0081] The above air injection unit (120) can be configured to inject air toward the sliding area, more specifically, the pet-edge, of the electrode (20) taken out from the second coating unit (110').

[0082] Figure 7 is a schematic diagram of an air injection unit according to exemplary embodiments of the present invention.

[0083] Referring to FIGS. 4 to 5 and 7, the air injection unit (120) can move the electrode slurry of the PET-edge to the periphery by injecting air toward the PET-edge of the electrode (20) in order to reduce the thickness of the PET-edge at the edge in the width direction (Y-axis direction) of the second electrode active material layer (23) formed on the second surface of the current collector (21).

[0084] After the electrode slurry is completely dried, it is difficult for the electrode slurry to move toward the non-conductive part by air injection, so it is preferable that the air injection part (120) be placed before the electrode (20) is introduced into the second drying part (130').

[0085] In one embodiment, the air injection unit (120) may be positioned on a transport path between the second coating unit (110') and the second drying unit (130'). Here, the transport path between the second coating unit (110') and the second drying unit (130') includes both the transport path of the second coating unit (110') and the transport path in front of the second coating unit (110') and the second drying unit (130').

[0086] The transport path of the second coating section (110') may refer to a transport path close to the slot die (111') and may mean a transport path until the electrode (20) is taken out from the coating roller (112').

[0087] The transport path between the second coating section (110') and the second drying section (130') may refer to the transport path from when the electrode (20) is taken out from the coating roller (112') to before being put into the second drying section (130').

[0088] Accordingly, in the electrode manufacturing system (100) according to the present invention, the electrode (20) can be sequentially transported through the first coating unit (110), the first drying unit (130), the second coating unit (110'), the air injection unit (120), and the second drying unit (130').

[0089] Referring to FIG. 7, in one embodiment, the air injection unit (120) may include an air pipe (121), a nozzle (122), and an air supply unit (not shown). The air supply unit may be configured to supply compressed air to the air pipe (121). The air pipe (121) may be a pipe through which air flows. The air pipes (121) may be installed in parallel in the width direction (Y-axis direction) of the electrode. At least one nozzle (122) may be installed in the air pipe (121). A nozzle valve (not shown) may be provided in at least one nozzle (122). By opening and closing each nozzle valve, air flowing in the air pipe may be sprayed to the outside through the nozzle. In addition, the amount of air to be sprayed may be controlled depending on the degree of opening and closing of the nozzle valve.

[0090] Referring to FIG. 5, in one embodiment, the air injection unit (120) may be configured to inject air in an inclined direction relative to an imaginary extension of the flat surface of the maintenance unit. Accordingly, the electrode slurry in a relatively thickly applied portion may be moved to the surrounding area by the high-pressure air injected from the air injection unit (120).

[0091] In addition, the air injection unit (120) may be configured to allow for angle adjustment of the air injection direction. Accordingly, the direction of the injected air can be appropriately adjusted.

[0092] Referring to FIG. 7, the air injection units (120) may be respectively arranged on both edges along the width direction (Y-axis direction) of the electrode (20), and two or more air injection units (120) may be spaced apart from each other along the transport direction (X-axis direction) of the electrode (20).

[0093] An electrode manufacturing system (100) according to one embodiment may further include a measuring unit (not shown) configured to measure a coating amount of electrode slurry applied to a maintenance unit, and an air injection unit controller (not shown) configured to adjust an air injection angle, an air injection position, and an air injection intensity based on the coating amount received from the measuring unit.

[0094] In one embodiment, the measuring unit may be configured to measure in real time the coating amount of the electrode slurry near the boundary between the maintenance portion and the uncoated portion. Here, the boundary between the maintenance portion and the uncoated portion refers to the edges on both sides in the width direction (Y-axis direction) of the second electrode active material layer (23) formed from the electrode slurry applied to the second surface of the current collector (21). Since the PET edge occurs near the boundary between the maintenance portion and the uncoated portion, specifically, from the point where the thickness of the electrode active material layer begins to decrease in the electrode width direction (Y-axis direction), the measuring unit is configured to measure near the boundary between the maintenance portion and the uncoated portion.

[0095] When the air injection unit (120) injects air, the measuring unit can be configured to measure the electrode slurry coating amount at the electrode edge in real time and transmit the measurement information to the air injection unit controller so that air injection conditions such as the air injection angle, air injection position, and air injection intensity are optimized.

[0096] And the air injection controller can be configured to determine whether a pet edge exists at both width-wise edges of the electrode (100) based on the measurement information received in real time. The presence of a pet edge can be determined by comparing the measurement information received from the measurement unit with a preset coating amount at the width-wise (Y-axis direction) edge of the electrode active material layer or a preset thickness length of the electrode active material layer.

[0097] In addition, the air injection controller may be configured to determine at least one condition among an air injection angle, an air injection position, and an air injection strength of air injected from the air injection unit to an appropriate level based on the measurement information received in real time to reduce the coating amount of the electrode slurry or the application thickness of the electrode slurry at a location where a pet edge exists. To this end, the air injection controller may be configured to have appropriate air injection conditions in advance according to the coating amount of the electrode slurry or the application thickness of the electrode slurry at a location where a pet edge exists.

[0098] In one embodiment, the measuring unit may be configured to calculate the coating amount of the electrode slurry in real time based on an X-ray absorption method. An example of such a measuring unit may be a web gauge.

[0099] In another embodiment, the measuring unit may be configured to calculate the coating amount of the electrode slurry in real time based on the measured distance from the measuring position to the holding unit. Such a measuring unit may be exemplified by a confocal sensor.

[0100] The installation location of the above-mentioned measuring unit is not particularly limited, but it is preferably installed in the second coating unit or downstream thereof, where the occurrence of a pet edge can be confirmed. Specifically, it is preferably installed downstream of the slot die (111') of the second coating unit (110'). However, it is not limited thereto, and it may be installed downstream of the second coating unit, but may also be installed on the transport path of the front end of the second drying unit, or may be installed downstream of the second drying unit.

[0101] An electrode manufacturing system (100) according to one embodiment may include an unwinder unit (150) provided in front of a first coating unit (110) to supply a current collector (21) to the first coating unit (110); and a rewinder unit (170) formed in the rear of a second drying unit (130') to wind up an electrode (20) on which coating and drying of electrode slurry have been completed. A current collector (21) in the form of a metal foil may be supplied in a state wound up in the unwinder unit (150). The supplied current collector may sequentially pass through the first coating unit (110), the first drying unit (130), the second coating unit (110'), the air injection unit (120), and the second drying unit (130'), and then be wound up in the rewinder unit (170). The electrode, which has undergone double-sided coating and drying of the electrode slurry, can be wound in a rewinder section (170) and then manufactured into an electrode through the next step, such as a slitting section or a punching section.

[0102] An electrode manufacturing system according to one embodiment may include a conveyor line that continuously transports the electrode current collector (21) from the time it is supplied from the unwinder unit (150) until it is wound on the rewinder unit (170). The conveyor line may be configured to continuously supply and transport the electrode current collector (21), and accordingly, the electrode current collector (21) sequentially passes through the first coating unit (110), the first drying unit (130), the second coating unit (110'), the air injection unit (120), and the second drying unit (130').

[0103]

[0104] (Example 2)

[0105] The present invention provides a method for manufacturing an electrode as a second embodiment.

[0106] Figure 8 is a flowchart illustrating a method for manufacturing an electrode according to exemplary embodiments of the present invention.

[0107] Referring to FIG. 8, a method for manufacturing an electrode according to exemplary embodiments may include a first coating step (P110) of applying electrode slurry to a first surface of a transported current collector; a first drying step (P120) of drying the electrode slurry applied to the first surface; a second coating step (P130) of applying electrode slurry to a second surface of the transported current collector; a step (P140) of measuring a coating amount of electrode slurry near a boundary between a holding portion and a non-coating portion; a step (P150) of determining whether a PET-edge exists based on the measured coating amount; a step (P160) of spraying air to the PET-edge to remove the PET-edge when it is determined that a PET-edge exists; and a second drying step (P170) of drying the electrode slurry applied to the second surface.

[0108] A method for manufacturing an electrode according to exemplary embodiments measures in real time the coating amount of electrode slurry applied to the second surface of a current collector, determines whether a pet-edge has occurred at the edge in the electrode width direction (Y-axis direction) based on the measured coating amount information, and if it is determined that a pet-edge has occurred, air is sprayed on the pet-edge to remove the pet-edge, thereby causing the electrode slurry of the pet-edge to spread toward the non-coated portion, thereby preventing the formation of the pet-edge.

[0109] In addition, in an electrode process in which the coating step and drying step of the electrode slurry are performed continuously, the production efficiency can be improved by preventing the creation of a pet edge at the edge in the width direction of the electrode without process fluctuation.

[0110] A method for manufacturing an electrode according to one embodiment can be performed by the electrode manufacturing system (100).

[0111] The first coating step (P110) and the second coating step (P130) may be performed by the first and second coating units (110, 110'), respectively, the first drying step (P120) and the second drying step (P170) may be performed by the first and second drying units (130, 130'), respectively, the step of measuring the coating amount (P140) may be performed by the measuring unit, the step of determining whether the pet-edge exists (P150) may be performed by the air injection unit controller, and the step of spraying air to the pet-edge (P160) may be performed by the air injection unit.

[0112] Since the specific details of the first coating step (P110) to the second drying step (P170) have been described in detail above, redundant descriptions will be omitted.

[0113]

[0114] (Example 3)

[0115] The present invention provides an electrode for a lithium secondary battery as a third embodiment.

[0116] Figure 9 is a cross-sectional view of an electrode according to exemplary embodiments.

[0117] Referring to FIG. 9, an electrode (20) according to exemplary embodiments includes a current collector (21); and first and second electrode active material layers (22, 23) formed on first and second surfaces of the current collector, respectively, wherein the first electrode active material layer (22) includes a first sliding area (22S) that is inclined with respect to a plane of the current collector (21), and the second electrode active material layer (23) includes a second sliding area (23S) that is inclined with respect to a plane of the current collector (21).

[0118] The first electrode active material layer is formed from the electrode slurry applied to the first surface of the current collector as described above, and the second electrode active material layer is formed from the electrode slurry applied to the second surface of the current collector. As described above, after the second coating unit applies the electrode slurry to the second surface of the current collector, the air spraying unit sprays high-pressure air to a portion where the electrode slurry is applied, where a pet edge is expected to occur, specifically, to both edges in the horizontal direction (Y direction). At this time, the portion of the electrode slurry application portion where the air is sprayed may have a concave shape due to the pressure of the air.

[0119] Accordingly, the shape of the second sliding region formed through the air injection process and the shape of the first sliding region formed without the air injection process are bound to be different. Specifically, when the second electrode active material layer and the first electrode active material layer rotated 180° are overlapped, the inclined surface (23S) of the second sliding region may have a concave portion (23SR) having an internally recessed shape with respect to the inclined surface of the first sliding region (22S).

[0120] If the above electrode is a positive electrode and the sliding region includes a concave portion, the capacity of the sliding region facing the negative electrode is reduced, which has the advantage of reducing the risk of NP Ratio reversal in that area.

[0121] In one embodiment, the transverse direction (TD, Y direction) length y of the second electrode active material layer (23) may be 0.99 to 1.01, preferably 1, of the transverse direction length x of the first electrode active material layer (22). When manufacturing the electrode, the design is made so that the y value and the x value are the same, but due to tolerance, the y value may be in the range of 0.99 to 1.01 of the x value. In addition, the thickness T1 of the first electrode active material layer is preferably the same as the thickness T2 of the second electrode active material layer (23).

[0122] In one embodiment, the angle b formed by the inclined surface of the second sliding region (23S) with the plane of the current collector (21) may be 0.99 to 1.01, preferably 1, of the angle a formed by the inclined surface of the first sliding region (22S) with the plane of the current collector (21). When manufacturing the electrode, the design is made so that the values ​​of b and a are the same, but due to tolerance, b may be in the range of 0.99 to 1.01 of a.

[0123] In one embodiment, the transverse length d of the second sliding region (23S) may be 0.99 to 1.01, preferably 1, of the transverse length c of the first sliding region (22S). When manufacturing the electrode, the design is such that the d value and the c value are the same, but due to tolerance, the d may be in the range of 0.99 to 1.01 of the c.

[0124]

[0125] The present invention has been described in more detail through the drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

Claims

1. A coating section including a slot die configured to discharge electrode slurry; and a coating roller disposed spaced apart from the slot die and configured to support a current collector; An air injection unit configured to inject air toward the boundary between the holding portion and the non-stick portion of the electrode taken out from the above coating portion; and A drying unit for drying the electrode slurry; The above coating part is composed of a first coating part that applies electrode slurry to a first surface of the current collector and a second coating part that applies electrode slurry to a second surface of the current collector. An electrode manufacturing system characterized in that the air injection unit is positioned on a transport path between the second coating unit and the drying unit.

2. In claim 1, A manufacturing system for an electrode in which the electrode is sequentially transported through the first coating section, the drying section, the second coating section, the air injection section, and the drying section.

3. In claim 1, An electrode manufacturing system in which the air injection unit is configured to inject air in an inclined direction with respect to an imaginary extension of the flat surface of the maintenance unit.

4. In claim 1, The above air injection unit is an electrode manufacturing system configured to enable adjustment of the angle of the air injection direction.

5. In claim 1, A measuring unit configured to measure the coating amount of electrode slurry applied to the maintenance unit; and An electrode manufacturing system further comprising an air injection unit controller configured to adjust an air injection angle, an air injection position, and an air injection strength based on a coating amount received from the above measuring unit.

6. In claim 5, The above measurement unit is an electrode manufacturing system configured to calculate the coating amount of electrode slurry in real time based on an X-ray absorption method.

7. In claim 5, An electrode manufacturing system in which the above measuring unit is configured to calculate the coating amount of the electrode slurry in real time based on the measured distance from the measuring position to the above maintenance unit.

8. In claim 5, The above measurement unit is a manufacturing system for an electrode placed downstream of the slot die of the second coating unit.

9. In claim 5, The above measurement unit is an electrode manufacturing system configured to measure the vicinity of the boundary between the maintenance unit and the non-maintenance unit.

10. In claim 1, The above slot die is, Two or more die blocks; and A system for manufacturing an electrode comprising a shim plate interposed between die blocks to form a slot.

11. A first coating step of applying electrode slurry to the first surface of the transported current collector; A first drying step of drying the electrode slurry applied to the first surface; A second coating step of applying electrode slurry to the second surface of the transferred current collector; A step of measuring the coating amount of electrode slurry near the boundary between the maintenance part and the unmaintained part; A step of determining whether a pet-edge exists based on the measured coating amount; A step of blowing air to the pet edge to remove the pet edge when it is determined that a pet edge exists; and A second drying step of drying the electrode slurry applied to the second surface; A method for manufacturing an electrode including:

12. In claim 11, A method for manufacturing an electrode, wherein the above electrode slurry is a positive electrode slurry.

13. An electrode comprising a current collector; and first and second electrode active material layers formed on one side and the other side of the current collector, The first and second electrode active material layers each include first and second sliding regions that are inclined with the plane of the current collector, An electrode characterized in that when the second electrode active material layer and the first electrode active material layer rotated 180° are overlapped, the inclined surface of the second sliding region has a concave portion having an internally recessed shape with respect to the inclined surface of the first sliding region.

14. In claim 11, The above electrode is a positive electrode.

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