KR102359521B1 - Dry material coating apparatus - Google Patents

Abstract

The present invention relates to a dry coating apparatus for forming an electrode active material layer with a dry coating material on a current collector, which includes: first rollers and second rollers rotated in different directions and installed adjacently at predetermined intervals; a first material supply unit for supplying a dry coating material between the first roller and the second roller; third and fourth rollers installed parallel to the first roller and the second roller, rotated in different directions and installed adjacently at predetermined intervals; a second material supply unit for supplying a dry coating material between the third roller and the fourth roller; a first gap adjusting unit adjusting a gap between the first roller and the second roller by pushing or pulling the first roller based on the second roller; and a second gap adjusting unit for adjusting the gap between the third roller and the fourth roller by pushing or pulling the third roller based on the fourth roller, wherein a rotational speed of the second roller is faster than the rotational speed of the first roller, and a rotational speed of the fourth roller is faster than the rotational speed of the third roller.

Description

Dry material coating apparatus

The present invention relates to a dry coating apparatus, and more particularly, to a dry coating apparatus for forming an electrode active material layer by coating a dry coating material on the surface of a current collector of an electrode included in an energy storage device such as a secondary battery.

With the increase in technology development and demand for mobile devices, the demand for energy storage devices such as secondary batteries is also rapidly increasing. Among them, lithium secondary batteries are widely used as energy sources for various mobile devices in that they have high energy density and operating voltage, and excellent storage and lifespan characteristics.

These lithium secondary batteries are attracting attention as an energy source for eco-friendly vehicles (electric vehicles, hybrid vehicles, etc.), which are being proposed as a way to solve air pollution caused by gasoline or diesel vehicles using fossil fuels. In order to apply the lithium secondary battery to the eco-friendly vehicle, it is required that the lithium secondary battery has high output characteristics.

In order to increase the output characteristics of the lithium secondary battery, the development of an electrode structure in which an electrode active material layer having a two-layer structure is formed on a current collector is attracting attention. As a method of forming the electrode active material layer having a two-layer structure on the current collector, a method of coating the electrode active material slurry on the upper and lower portions of the current collector is applied. However, this method has a problem in that the electrode active material layer having a uniform two-layer structure is not formed or the process efficiency is deteriorated as the electrode active material slurry is used. That is, the electrode active material slurry is not sprayed to have a uniform thickness because the electrode active material slurry is not evenly sprayed due to the separation distance between the nozzles while the electrode active material slurry is sprayed onto the current collector through the nozzle. In addition, as the electrode active material slurry sprayed on the current collector needs to be dried, the process efficiency of the electrode active material layer is reduced.

Therefore, there is a demand for technology development capable of efficiently forming an electrode active material layer having a uniform thickness.

Republic of Korea Patent Publication No. 2017-0048363

An object of the present invention is to provide a dry coating apparatus capable of efficiently forming an electrode active material layer while having a uniform thickness and high density. Specifically, the present invention relates to a gap between a pair of rollers forming a film by fiberizing a dry coating material, and another pair of rollers driven to laminate the fiberized film formed on the surface of any one of the pair of rollers to the current collector. An object of the present invention is to provide a dry coating device capable of independently controlling the distance between rollers.

In order to solve the above problems, the present invention provides a dry coating device for forming an electrode active material layer with a dry coating material on a current collector, wherein the first roller and the second roller rotate in different directions and are installed adjacent to each other at a predetermined distance. 2 rollers; a first material supply unit for supplying a dry coating material between the first roller and the second roller; a third roller and a fourth roller installed parallel to the first roller and the second roller, rotating in different directions, and adjacent to each other at a predetermined distance; a second material supply unit for supplying a dry coating material between the third roller and the fourth roller; a first gap adjusting unit for adjusting the distance between the first roller and the second roller by pushing or pulling the first roller based on the second roller; and a second gap adjusting unit for adjusting the distance between the third roller and the fourth roller by pushing or pulling the third roller based on the fourth roller, wherein the rotational speed of the second roller is determined by the rotation speed of the first roller It provides a dry coating apparatus faster than the rotation speed, and the rotation speed of the fourth roller is faster than the rotation speed of the third roller.

In the dry coating apparatus according to the present invention, the distance between the second roller and the fourth roller is adjusted by simultaneously moving the third roller and the fourth roller in a direction perpendicular to the rotation axes of the third and fourth rollers. It may further include a third interval adjusting unit.

In addition, it may further include an air cylinder installed between the second roller and the fourth roller.

Here, the dry coating material may include a carbon material and a binder resin.

On the other hand, in the dry coating apparatus according to the present invention, the dry coating material passes between the first roller and the second roller and is converted into a fibrous film, and the dry coating apparatus according to the present invention has a predetermined distance from the second roller It may further include a first flattening roller installed adjacent to and pressurizing the fibrous film to flatten it.

In addition, in the dry coating apparatus according to the present invention, the dry coating material passes between the third roller and the fourth roller and is converted into a fiber-forming film, and the dry coating apparatus according to the present invention has a predetermined distance from the fourth roller It may further include a second flattening roller installed adjacent to and pressurizing the fibrous film to flatten it.

In addition, the dry coating apparatus according to the present invention may further include a pair of pressure rollers for pressing the electrode active material layer formed on the current collector.

Since the dry coating apparatus according to the present invention forms the electrode active material layer using a dry coating material that does not contain a solvent, contamination by solvent is not induced during the coating process, and a process for removing the solvent is not required ( no solvent removal means required). That is, the present invention can form an electrode active material layer with excellent physical properties with high efficiency by providing a dry coating device having a compact structure.

In addition, since the dry coating apparatus according to the present invention can independently control the distance between each pair of rollers, it is possible to efficiently control the thickness of the electrode active material layer. In addition, since it includes a roller capable of increasing the flatness of the electrode active material layer, it is possible to form an electrode active material layer having a flat and uniform thickness, or a combination of the electrode active material layer and the current collector, thereby improving the performance of the electrode as a final product. can be raised

1 is a schematic diagram for explaining an installation structure between each roller included in the dry coating apparatus according to an embodiment of the present invention.
2 is a schematic diagram for explaining a dry coating apparatus according to an embodiment of the present invention.
3 is a schematic diagram for explaining the rotational speed between each roller included in the dry coating apparatus according to an embodiment of the present invention.
4 is a schematic view for explaining the adjustment of the spacing between the rollers included in the dry coating apparatus according to an embodiment of the present invention.
5 is a schematic diagram illustrating first and second flattening rollers included in the dry coating apparatus according to an embodiment of the present invention.
6 is a schematic view for explaining a pressure roller included in the dry coating apparatus according to an embodiment of the present invention.
7 is a schematic diagram for explaining a dry coating apparatus according to another embodiment of the present invention.
8 is a schematic diagram for explaining the horizontal movement between each roller in the dry coating apparatus according to another embodiment of the present invention.
9 and 10 are reference views for explaining a fiberized film formed through a dry coating apparatus according to another embodiment of the present invention.

Throughout this specification, when a part 'includes' a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated. Also, in this specification, terms such as 'first' or 'second' are for distinguishing one component from other components, and the scope of rights should not be limited by these terms. For example, a first component may be termed a second component, and similarly, a second component may also be termed a first component.

Meanwhile, in the drawings, in order to clearly express the components of each device, the sizes such as width and thickness of each component are slightly enlarged. In the description of the drawings as a whole, it has been described from an observer's point of view, and when it is mentioned that one component is located above another component, this means that the component is located directly above another component or an additional component is interposed between the components. It includes all the meanings that can be.

Hereinafter, the present invention will be described in detail with reference to the drawings.

The present invention relates to a device used in the process of manufacturing an electrode in which a current collector and an electrode active material are combined. Referring to FIGS. 1 and 2 as an embodiment, dry coating of an electrode active material material on the current collector 400 It relates to a dry coating apparatus 100 for coating the material 200 to form the electrode active material layer 300a. The dry coating apparatus 100 according to an embodiment of the present invention includes a first roller 111 and a second roller 112; a first material supply unit 120; a third roller 131 and a fourth roller 132; a second material supply unit 140; a first interval adjusting unit 150; and a second interval adjusting unit 160 .

The first roller 111 and the second roller 112 included in the dry coating apparatus 100 according to an embodiment of the present invention are installed adjacent to each other while being spaced apart from each other at a predetermined distance. The first roller 111 and the second roller 112 rotate in different directions so that the dry coating material 200 passing between the first roller 111 and the second roller 112 is formed into a fiber film 300 . , which will be described later in detail.

Each rotation speed of the first roller 111 and the second roller 112 is flexibly determined according to process conditions, and may be the same or different from each other. Specifically, the rotational speed (V ₂ ) of the second roller 112 so that the dry coating material 200 can smoothly move in one direction (specifically, the rotation direction of the second roller 112) as the dry coating material 200 is converted into the fiberizing film 300. Is faster than the rotation speed (V ₁ ) of the first roller 111 (V ₂ >V ₁ ) It is preferable (see FIG. 3 ). That is, when the rotation speed (V ₂ ) of the second roller 112 is faster than the rotation speed (V ₁ ) of the first roller 111 , the dry coating material 200 is smoothly transferred to the fiberization film 300 by shear force. can be switched

Each surface of the first roller 111 and the second roller 112 may be coated with a coating material containing chromium (Cr) in order to increase durability, releasability, and surface uniformity of the fiberized film.

The first material supply unit 120 included in the dry coating apparatus 100 according to an embodiment of the present invention supplies the dry coating material 200 between the first roller 111 and the second roller 112 . The structure of the first material supply unit 120 is not particularly limited as long as the dry coating material 200 can be smoothly supplied.

The third roller 131 and the fourth roller 132 included in the dry coating apparatus 100 according to an embodiment of the present invention are installed adjacent to each other while being spaced apart from each other at a predetermined distance. The third roller 131 and the fourth roller 132 are installed parallel to the first roller 111 and the second roller 112 , and the fourth roller 132 is spaced apart from the second roller 112 by a predetermined distance. It can be installed to face each other. For example, the first to fourth rollers (111, 112, 131, 132) are installed spaced apart from each other at a predetermined interval so that the rotation axes of each roller are on the same line, and the second roller 112 and the fourth roller 132 may be installed to be adjacent to each other. The third roller 131 and the fourth roller 132 rotate in different directions so that the dry coating material 200 passing between the third roller 131 and the fourth roller 132 is formed into a fiberizing film 300 . , which will be described later in detail.

Each rotation speed of the third roller 131 and the fourth roller 132 is flexibly determined according to process conditions, and may be the same or different from each other. Specifically, the rotational speed (V ₄ ) of the fourth roller 132 so that the dry coating material 200 can smoothly move in one direction (specifically, the rotation direction of the fourth roller 132) while being converted into the fiberizing film 300 Is faster than the rotation speed (V ₃ ) of the third roller 131 (V ₄ >V ₃ ) is preferred (see FIG. 3 ). That is, when the rotation speed (V ₄ ) of the fourth roller 132 is faster than the rotation speed (V ₃ ) of the third roller 131 , the dry coating material 200 is smoothly transferred to the fiberization film 300 by shear force. can be switched

Each surface of the third roller 131 and the fourth roller 132 may be coated with a coating material containing chromium (Cr) in order to increase durability, releasability, and surface uniformity of the fibrous film.

The second material supply unit 140 included in the dry coating apparatus 100 according to an embodiment of the present invention supplies the dry coating material 200 between the third roller 131 and the fourth roller 132 . The structure of the second material supply unit 140 is not particularly limited as long as the dry coating material 200 can be smoothly supplied.

The first gap adjusting unit 150 included in the dry coating apparatus 100 according to an embodiment of the present invention is based on the second roller 112 (based on the position of the second roller 112), the second 1 The gap between the first roller 111 and the second roller 112 is adjusted by pushing or pulling the roller 111 . Specifically, the first roller 111 is pushed toward the second roller 112 by the driving of the first gap adjusting unit 150 coupled to the first roller 111 , or, conversely, the first roller 111 moves the second roller 111 toward the second roller 112 . The distance d ₁ between the first roller 111 and the second roller 112 may be adjusted by pulling the first roller 111 away from the roller 112 (see FIG. 4 ). The driving of the first interval adjusting unit 150 may be performed in such a way that a mechanical cylinder is driven by a motor. Specifically, the first gap adjusting unit 150 may have a structure in which a mechanical cylinder, not a conventionally known hydraulic cylinder, is driven by a servomotor and a control unit. In this way, when the mechanical cylinder adjusts the interval (d ₁ ) between the first roller 111 and the second roller 112 with the first interval control unit 150 driven by the servomotor and the control unit, the interval adjustment precision is increased. It can be quickly controlled while increasing, thereby making it easy to control the thickness of the fiberized membrane 300 converted from the dry coating material 200 .

The second gap adjusting unit 160 included in the dry coating apparatus 100 according to an embodiment of the present invention is based on the fourth roller 132 (based on the position of the fourth roller 132), 3 The distance between the third roller 131 and the fourth roller 132 is adjusted by pushing or pulling the roller 131 . Specifically, the third roller 131 is pushed toward the fourth roller 132 by the driving of the second gap adjusting unit 160 coupled to the third roller 131 , or, conversely, the third roller 131 moves the fourth The distance d ₂ between the third roller 131 and the fourth roller 132 may be adjusted by pulling the third roller 131 away from the roller 132 (see FIG. 4 ). The driving of the second interval adjusting unit 160 may be performed in a manner in which a mechanical cylinder is driven by a motor. Specifically, the second interval adjusting unit 160 may have a structure in which a mechanical cylinder, not a conventionally known hydraulic cylinder, is driven by a servomotor and a control unit. In this way, when the mechanical cylinder adjusts the interval (d ₂ ) between the third roller 131 and the fourth roller 132 with the second interval control unit 160 driven by the servomotor and the control unit, the interval adjustment precision is increased. It can be quickly controlled while increasing, thereby making it easy to control the thickness of the fiberized membrane 300 converted from the dry coating material 200 .

Meanwhile, the dry coating apparatus 100 according to an embodiment of the present invention may further include a third gap adjusting unit 170 for adjusting the gap between the second roller 112 and the fourth roller 132 . Specifically, the third gap adjusting unit 170 is a third roller 131 and a fourth roller 132 in a direction (X) perpendicular to the respective rotation axes of the third roller 131 and the fourth roller 132 . (Positions of the third roller 131 and the fourth roller 132) may be moved simultaneously (or together) to adjust the distance d ₃ between the second roller 112 and the fourth roller 132 ( see Fig. 4). The third gap adjusting unit 170 may be driven by the driving unit 171 in a state in which the third roller 131 and the fourth roller 132 are coupled to move at the same time. The driving unit 171 is not particularly limited, but a linear stage structure in which driving control is easy as it includes a linear motor and a control unit may be applied. The electrode active material layer 300a formed on the current collector 400 as the distance d ₃ between the second roller 112 and the fourth roller 132 is adjusted by the third gap adjusting unit 170 ). thickness control can be facilitated. Here, the third interval adjusting unit 170 is installed on the side of the first roller 111 and the second roller 112, opposite to that shown in FIG. 2, and simultaneously in the direction perpendicular to the axis of rotation of the first roller 111 ) and the second roller 112 may be moved to adjust the interval d ₃ between the second roller 112 and the fourth roller 132 .

The dry coating apparatus 100 according to an embodiment of the present invention may further include an air cylinder 180 installed between the second roller 112 and the fourth roller 132 . The air cylinder 180 maintains the interval d ₃ between the second roller 112 and the fourth roller 132 at a set value (that is, the second roller 112 and the second roller 112 so as not to be smaller than the set value). The gap (d ₃ ) between the fourth rollers 132 is maintained), whereby the electrode active material layer 300a formed on the current collector 400 may have a uniform thickness and density.

The dry coating apparatus 100 according to an embodiment of the present invention may further include a first flattening roller 191 for planarizing the fibrous film 300 . Specifically, referring to FIG. 5 , in the dry coating apparatus 100 according to the present invention, the fiberization film 300 is formed by passing the dry coating material 200 between the first roller 111 and the second roller 112 . It may further include a first flattening roller 191 installed adjacent to the second roller 112 while being spaced apart from the second roller 112 at a predetermined distance to be flattened. The first flattening roller 191 presses the fibrous film 300 while rotating in a different direction from the second roller 112 , thereby increasing the thickness uniformity, flatness, density, etc. of the fibrous film 300 . can Here, the rotation speed of the first flattening roller 191 may be set in consideration of the rotation speed of the second roller 112 . In addition, the surface of the first flattening roller 191 may be coated with a coating material containing chromium (Cr) in order to increase durability, releasability, and surface uniformity of the fiberized film.

The dry coating apparatus 100 according to an embodiment of the present invention may further include a second flattening roller 192 for planarizing the fibrous film 300 . Specifically, referring to FIG. 5 , in the dry coating apparatus 100 according to the present invention, the fiberization film 300 is formed by passing the dry coating material 200 between the third roller 131 and the fourth roller 132 . It may further include a second flattening roller 192 installed adjacent to the fourth roller 132 while being spaced apart from the fourth roller 132 at a predetermined distance to be flattened. The second flattening roller 192 presses the fiberizing film 300 while rotating in a different direction from the fourth roller 132 , thereby improving the thickness uniformity, flatness, density, etc. of the fiberizing film 300 . can be raised Here, the rotation speed of the second flattening roller 192 may be set in consideration of the rotation speed of the fourth roller 132 . In addition, the surface of the second flattening roller 192 may be coated with a coating material containing chromium (Cr) in order to increase durability, releasability, and surface uniformity of the fiberized film.

The dry coating apparatus 100 according to an embodiment of the present invention may further include a pair of pressure rollers 193 for pressing the electrode active material layer 300a. Specifically, referring to FIG. 6 , the dry coating apparatus 100 according to the present invention provides a pair of pressing each of the electrode active material layers 300a formed (combined) on one side and the other side of the current collector 400 , respectively. It may further include a pressure roller 193 of. As the pressure roller 193 presses the electrode active material layer 300a, the thickness uniformity and density of the electrode active material layer 300a may be increased, and the bonding force between the current collector and the electrode active material layer 300a may be increased. The surface of the pressure roller 193 may be coated with a coating material containing chromium (Cr) in order to increase durability, releasability, and surface uniformity of the electrode active material layer.

Meanwhile, the dry coating material 200 used to form the electrode active material layer 300a in the dry coating apparatus 100 according to an embodiment of the present invention may include a carbon material and a binder resin. That is, the dry coating material 200 in the present invention may be a mixture of a binder resin and a carbon material (specifically, a mixture of a binder resin powder and a carbon material powder). The dry coating material 200 may pass between the first roller 111 and the second roller 112 in the heated state and/or between the third roller 131 and the fourth roller 132 in the heated state. At this time, heat and pressure (shear force) are received. At this time, fiberization of the binder resin included in the dry coating material 200 occurs, and the dry coating material 200 passing between each roller is converted into a fibrous membrane 300 . Here, since the dry coating material 200 also includes a carbon material, the carbon material is bonded to the fiberized film 300 formed by passing the dry coating material 200 between each roller in a dispersed state. That is, the fibrous membrane 300 serves as a matrix to allow the carbon material to be bonded in a dispersed state, and may be formed of an anisotropically formed fiber structure (eg, fibrils). Here, that the fiber structure has anisotropy may be defined as weaving while each fiber (fiber strand) is arranged in a direction perpendicular to the rotation axis of each roller. The fiberized membrane 300 in which the carbon material is dispersedly bonded may have a compression density of 0.45 gm/cm 3 or more.

The carbon material included in the dry coating material 200 may not be particularly limited as long as it is a known electrode active material material. Specifically, the carbon material may be activated carbon, graphite, carbon black, a conductive polymer, or a mixture thereof. The conductive polymer may not be particularly limited as long as it is known as a polymer exhibiting conductivity.

The binder resin included in the dry coating material 200 may not be particularly limited as long as it is a known thermoplastic resin. Specifically, the binder resin may be polyethylene, polypropylene, a fluorine-based resin (eg, polytetrafluoroethylene), or a mixture thereof.

Each content of the carbon material and the binder resin included in the dry coating material 200 is not particularly limited, but based on the total weight% of the dry coating material 200, the content of the carbon material may be 50 to 99% by weight, and , the content of the binder resin may be 1 to 50% by weight.

As described above, in the present invention, since the electrode active material layer 300a is formed using the dry coating material 200 that does not contain a solvent, contamination by the solvent may not be caused during the process, and a means for removing the solvent or It can show high efficiency as no process is required.

Meanwhile, the current collector 400 in the present invention is not particularly limited as long as it is known as a current collector material in the field of batteries and may be used. Specifically, the current collector 400 may be a copper foil, a nickel foil, or an aluminum foil.

The present invention provides a dry coating apparatus 100 shown in FIG. 7 in another embodiment. Specifically, the dry coating apparatus 100 according to another embodiment of the present invention includes each of the components shown in FIG. 1, and includes a first and/or second horizontal movement driving unit as shown in FIG. As such, it is described in detail as follows.

Dry coating apparatus 100 according to another embodiment of the present invention includes a first roller 111 and a second roller 112; a first material supply unit 120; a third roller 131 and a fourth roller 132; a second material supply unit 140; and a first horizontal movement driving unit 110 ′.

The first roller 111 and the second roller 112, the first material supply unit 120, the third roller 131, and the fourth roller included in the dry coating apparatus 100 according to another embodiment of the present invention. Description of the 132 and the second material supply unit 140 are the same as those described for describing the dry coating apparatus 100 (refer to FIGS. 1 and 2 ) according to an embodiment of the present invention, so to be omitted. do. In addition, the description of the dry coating material 200, the fibrous film 300, the electrode active material layer 300a and the current collector 400 applied to the driving of the dry coating apparatus 100 according to another embodiment of the present invention The same applies as described above.

The first horizontal movement driving unit 110 ′ included in the dry coating apparatus 100 according to another embodiment of the present invention includes the first roller 111 while the first roller 111 and the second roller 112 rotate. ) and in a direction parallel to the axis of rotation of the second roller 112 , the relative positions of the first roller 111 and the second roller 112 are changed. For example, in the process of rotating the first roller 111 and the second roller 112, the second roller 112 only rotates about the axis of rotation of the second roller 112, and the first roller 111 While rotating around the axis of rotation of the first roller 111 by the first horizontal movement driving unit 110', the first roller 111 moves (moves) in a direction parallel to the axis of rotation of the first roller ( The relative positions of the 111) and the second roller 112 may be changed. Specifically, in FIG. 7 , the second roller 112 rotates only, and the first roller 111 rotates, while the first horizontal movement driving unit 110 ′ moves left and right reciprocally (up and down reciprocation when the drawing direction is changed) This can be done repeatedly. As such, the first horizontal movement driving unit 110 ′ for changing the relative positions of the first roller 111 and the second roller 112 is not particularly limited, but the direction required by the linear motor and the control unit (XY axis direction) A linear stage structure that can be driven in conjunction with each other may be applied.

As the relative positions of the first roller 111 and the second roller 112 are changed by the first horizontal movement driving unit 110', the present invention provides a fiberizing film 300 with high flatness and high tensile strength and electrical conductivity. A high electrode active material layer 300a may be formed. Specifically, the dry coating material 200 passes between the first roller 111 and the second roller 112 and is converted into a fibrous membrane 300 having a fibrous structure, at this time, the first horizontal movement driving unit 110' When the first roller 111 reciprocates in a direction parallel to the axis of rotation by the It may be dispersed or relaxed in a direction parallel to the axis of rotation. That is, referring to FIG. 8 , when the first roller 111 and the second roller 112 only rotate, the fiber structure of the fibrous membrane 300 shows only anisotropy (refer to FIG. 8 (a)) , when the first roller 111 rotates and reciprocates by the first horizontal movement driving unit 110 ′, the anisotropy of the fiber structure of the fiberizing membrane 300 is broken (see (B) of FIG. 8 ) ). Specifically, when both the first roller 111 and the second roller 112 only rotate, each fiber is arranged in a direction perpendicular to the rotation axis of each roller to form a fiberizing film 300 (anisotropic formation), When the first roller 111 simultaneously rotates and reciprocates by the first horizontal movement driving unit 110 ′, a force is applied to each fiber in a direction parallel to the rotation axis of each roller so that it is perpendicular to the rotation axis of each roller. Rather than forming the fibrous membrane 300 while uniformly arranging each fiber in the direction, the fibrous membrane 300 is formed by bending and arranging the fiber structure. Here, as the anisotropy of the fiber structure collapses, the fibrous membrane 300 has a zigzag type ((c), (d)), a wavy type ((b)), or a wavy type ((a)) as shown in FIG. 9 , etc. A fiber structure having a may be formed. The zigzag, wavy, or wavy fiber structure may be in a regular or irregular shape.

As described above, when the anisotropy of the fiber structure of the fiberization membrane 300 is dispersed or relieved in the horizontal direction, the network of the fiber structure is strengthened, so that the flatness and tensile strength of the fiberization membrane 300 can be improved. In addition, when the dry coating material 200 includes a carbon material, the contact area between the carbon materials is increased by the reinforced fiber structure network (see FIG. 10 ), and thus the fiberized film 300 is formed on the current collector 400 . The electrical conductivity of the electrode active material layer 300a formed by bonding may be increased.

The dry coating apparatus 100 according to another embodiment of the present invention may further include a second horizontal movement driving unit 120 ′ for changing the relative positions of the third roller 131 and the fourth roller 132 . . Specifically, the second horizontal movement driving unit 120' moves in a direction parallel to the axis of rotation of the third roller 131 and the fourth roller 132 while the third roller 131 and the fourth roller 132 rotate. The relative positions of the third roller 131 and the fourth roller 132 are changed. For example, in the process of rotating the third roller 131 and the fourth roller 132 , the fourth roller 132 rotates only about the axis of rotation of the fourth roller 132 , and the third roller 131 . is moved (moved) in a direction parallel to the axis of rotation of the third roller 131 while rotating around the axis of rotation of the third roller 131 by the second horizontal movement driving unit 120 ′, and the third roller 131 ) and the relative positions of the fourth roller 132 may be changed. Specifically, in FIG. 7 , the fourth roller 132 rotates only, and the third roller 131 rotates, while the second horizontal movement driving unit 120 ′ moves left and right reciprocally (up-and-down reciprocating movement when the drawing direction is changed) This can be done repeatedly. As such, the second horizontal movement driving unit 120' for changing the relative positions of the third roller 131 and the fourth roller 132 is not particularly limited, but the direction required by the linear motor and the control unit (XY axis direction) A linear stage structure that can be driven in conjunction with each other may be applied.

Here, the description of the fact that the flatness and tensile strength of the fiberizing film 300 and the electrical conductivity of the electrode active material layer 300a are increased by the second horizontal movement driving unit 120' is the first horizontal movement driving unit 110'. Since it is the same as the content described for the description, it will be omitted.

On the other hand, the dry coating apparatus 100 according to another embodiment of the present invention includes a first interval adjusting unit 150 and a second interval adjusting unit ( 160), a third spacing adjusting unit 170, an air cylinder 180, a first flattening roller 191, a second flattening roller 192, and a pressure roller 193 may be optionally further included in some cases. . Here, when the first to third interval adjusting units 150 , 160 , 170 are optionally further included in the dry coating apparatus 100 according to another embodiment of the present invention, their driving depends on the driving method of other components. It can be appropriately changed and applied accordingly. For example, the first and second interval adjusting units 150 and 160 may be driven by a linear stage structure including a linear motor and a control unit. In addition, the third interval adjusting unit 170 is a linear stage including a linear motor and a control unit in the presence of a connecting unit 172 that allows the third roller 131 and the fourth roller 132 to be coupled (connected). It may be driven by a structure, or a structure in which a mechanical cylinder and a motor (eg, a servomotor) are combined.

Since the dry coating apparatus according to the present invention described above can independently control the separation distance between each roller, it is possible to easily control the fibrous film formed through each roller to have a required thickness. In addition, it is possible to quickly control the thickness deviation of the fiberized film due to process changes during the coating process for a long time.

In addition, the dry coating apparatus according to the present invention disperses (horizontally disperses) the anisotropy of the structure of fibers (eg, fibril) constituting the fibrous film, so the flatness and tensile strength of the fibrous film are high, and the dispersibility of the carbon material is excellent. can do. As a result, it is possible to obtain the effect of increasing the electrical conductivity of the electrode active material layer formed on the current collector. Specifically, the tensile strength of the fibrous membrane obtained through the dry coating apparatus according to the present invention may be 0.1 to 0.2 N/mm 2 , and the electrical conductivity of the electrode active material layer 300a may be 0.5 to 1 Ω.

Hereinafter, the present invention will be described in more detail by way of Examples. However, the following examples are intended to illustrate the present invention, and it is apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention, and the scope of the present invention is not limited thereto.

[Example 1]

An electrode active material layer was formed on the current collector using the dry coating apparatus shown in FIGS. 1 and 2 . At this time, aluminum foil (thickness: 30 μm) was used as the current collector, and a dry mixture of 50 wt% of activated carbon and 50 wt% of polytetrafluoroethylene was used as a dry coating material for forming the electrode active material. .

The dry mixture was supplied between the first and second rollers and between the third and fourth rollers heated to about 100 ° C through each material supply unit to induce fiberization of the dry mixture to form a fiberization film, and the formed fiberization film was The electrode active material layer (thickness: 150 μm) on the aluminum foil through the process of bonding to both sides of the aluminum foil as the current collector while moving along the second and fourth rollers, each having a higher rotation speed than the first and third rollers was formed. The electrode active material layer formation process was continued for 25 hours and then ended, and the gap between each roller was not adjusted during the formation process.

[Example 2]

After measuring the thickness of the electrode active material layer formed every 5 hours, if there was a thickness deviation, the formation process of the electrode active material layer was performed in the same manner as in Example 1, except that the interval between each roller was adjusted.

[Example 3]

The process of forming the electrode active material layer was performed in the same manner as in Example 1, except that the flattening roller shown in FIG. 5 was added to the second roller and the fourth roller, respectively, and the dry coating apparatus was driven.

[Example 4]

Instead of the dry coating apparatus shown in FIG. 2, horizontal movement of the first roller and the second roller (the first roller performs rotational movement and left and right reciprocating movement at the same time, and the second roller performs only rotational movement) is performed, and the third It is carried out except that the dry coating device shown in FIG. 7 is applied so that the horizontal movement of the roller and the fourth roller (the third roller performs rotational movement and left and right reciprocating movement at the same time, and the fourth roller performs only rotational movement) is applied The process of forming the electrode active material layer was performed in the same manner as in Example 1.

[Experimental example]

The physical properties of the fibrous membrane and the electrode active material layer obtained in each Example were evaluated in the following manner, and the results are shown in Table 1 below.

1. Tensile strength: The tensile strength of the fiberized membrane was measured by applying a known method.

2. Electrical conductivity: The electrical conductivity of the electrode active material layer was measured by applying a known method.

3. Flatness: After measuring and averaging the thickness of the electrode active material layer formed every 5 hours, it was evaluated whether there was any deviation compared with the thickness of the electrode active material layer formed initially.

division Tensile strength (N/㎟) Electrical Conductivity (Ω) flatness(%) Example 1 0.05 0.4 4-5% Example 2 0.08 0.7 2-3% Example 3 0.10 0.8 1-2% Example 4 0.15 One 2-3%

Referring to Table 1, it was confirmed that each physical property was improved by controlling the distance between the rollers or adding a flattening roller. In addition, it was confirmed that the tensile strength and electrical conductivity were very high as the first roller and the third roller were moved horizontally.

The above description describes the technical idea of the present invention using one embodiment, and various modifications and variations are possible without departing from the essential characteristics of the present invention by those of ordinary skill in the art to which the present invention pertains. Accordingly, the embodiments described in the present invention are not intended to limit the technical spirit of the present invention, but to illustrate, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: dry coating device
111: first roller 112: second roller
131: third roller 132: fourth roller
120: first material supply unit 140: second material supply unit
150: first interval control unit
160: second interval control unit
170: third interval adjusting unit 171: driving unit 172: connecting unit
180: air cylinder
191: first leveling roller 192: second leveling roller 193: pressure roller
110': first horizontal movement driving unit 120': second horizontal movement driving unit
200: dry coating material
300: fibrous membrane 300a: electrode active material layer
400: current collector

Claims (7)

In the dry coating device for forming an electrode active material layer with a dry coating material on a current collector,
a first roller and a second roller which rotate in different directions and are installed adjacent to each other at a predetermined distance;
a first material supply unit for supplying a dry coating material between the first roller and the second roller;
a third roller and a fourth roller installed parallel to the first roller and the second roller, rotated in different directions and installed adjacent to each other at a predetermined distance;
a second material supply unit for supplying a dry coating material between the third roller and the fourth roller;
a first gap adjusting unit for adjusting the distance between the first roller and the second roller by pushing or pulling the first roller based on the second roller; and
and a second gap adjusting unit for adjusting the distance between the third roller and the fourth roller by pushing or pulling the third roller based on the fourth roller,
The rotation speed of the second roller is faster than the rotation speed of the first roller, the rotation speed of the fourth roller is faster than the rotation speed of the third roller,
Each of the first interval adjusting unit and the second interval adjusting unit includes a servomotor and a mechanical cylinder driven by a control unit. According to claim 1,
Dry type further comprising a third gap adjusting unit for adjusting the distance between the second roller and the fourth roller by simultaneously moving the third roller and the fourth roller in a direction perpendicular to the rotation axes of the third and fourth rollers coating device. According to claim 1,
Dry coating apparatus further comprising an air cylinder installed between the second roller and the fourth roller. According to claim 1,
The dry coating material is a dry coating device comprising a carbon material and a binder resin. According to claim 1,
The dry coating material passes between the first roller and the second roller and is converted into a fibrous film,
The dry coating apparatus further comprising a first flattening roller installed adjacent to the second roller at a predetermined distance and flattening the fiberized film by pressing. According to claim 1,
The dry coating material passes between the third roller and the fourth roller and is converted into a fibrous film,
The dry coating apparatus further comprising a second flattening roller installed adjacent to the fourth roller at a predetermined distance and flattening the fiberized film by pressing. According to claim 1,
Dry coating apparatus further comprising a pair of pressure rollers for pressing the electrode active material layer formed on the current collector.

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