Coating device and method of manufacturing separator using same

Abstract

The present invention provides a coating device comprising: a storage unit containing a coating solution; a coating roll which is accommodated in the storage unit and transfers the coating solution, supplied from the storage unit, onto at least one surface of a substrate transported in one direction; and at least one positioning roll which is spaced apart from the storage unit and comes into contact with at least one end of the substrate in the width direction to adjust the height of the substrate.

Description

Coating device and method for manufacturing a separation membrane using the same

[0001] The present invention relates to a coating device and a method for manufacturing a separation membrane using the same.

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0097143, filed July 23, 2024, the entire contents of which are incorporated herein by reference.

[0003]

[0004] Recently, interest in energy storage technology has been growing. As its application expands to include energy for mobile phones, camcorders, laptops, and even electric vehicles, research and development efforts in electrochemical devices are becoming increasingly concrete. Electrochemical devices are attracting the most attention in this regard, and within this field, the development of rechargeable secondary batteries is a particular focus.

[0005] Secondary batteries are chemical batteries that utilize electrochemical reactions to continuously charge and discharge, enabling near-permanent use. They are categorized into lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and lithium secondary batteries. Among these, lithium secondary batteries dominate the secondary battery market due to their superior characteristics of high voltage and energy density compared to other types of batteries.

[0006] Lithium secondary batteries consist of an electrode assembly in which each active material is coated on a current collector, and an electrolyte is impregnated into a separator between the positive and negative electrodes. The separator of a lithium secondary battery is manufactured by applying a coating solution that forms a porous coating layer on a porous polymer substrate and then drying the solvent.

[0007] Examples of methods for applying a coating solution onto a porous polymer substrate, i.e., a substrate, include dip coating, die coating, roll coating, and comma coating. Here, roll coating refers to a method of transferring a coating solution from a storage unit containing the coating solution onto a substrate.

[0008] Meanwhile, the two ends of the substrate in the width direction may not be fixed and may tremble due to hot air during the process of transferring and drying the coating solution. This problem may cause the coating solution transferred to the two ends of the substrate to scatter to the surroundings, and the scattered coating solution may not be uniformly applied to the substrate. To solve this problem of deteriorating membrane quality, a method has been proposed in which the two ends of the substrate in the width direction are left uncoated without transferring the coating solution.

[0009] Meanwhile, the greater the number of uncoated areas on both ends of the substrate in the width direction, the greater the amount of material discarded during final slitting. Accordingly, there is a need for a novel coating device capable of controlling the area over which a coating solution is transferred in the width direction of the substrate, and a method for manufacturing a separator using the device.

[0010] The present invention was invented to solve the above-described problem, and specifically, the technical problem is to provide a coating device that does not transfer a coating liquid to both ends in the width direction of a substrate, and a method for manufacturing a separation membrane using the same.

[0011] In addition, the present invention has a technical problem of providing a separation membrane in which a coating layer is uniformly formed using the coating device.

[0012] In addition, the present invention has a technical problem of providing a coating device capable of changing the thickness and width of a coating layer along the longitudinal direction of a substrate and a method for manufacturing a separation membrane using the same.

[0013] To achieve this purpose, according to one aspect of the present invention, a coating device of the following embodiment and a method for manufacturing a separation membrane using the same are provided.

[0014] According to a first embodiment, a coating device is provided, comprising: a storage unit containing a coating liquid; a coating roll contained in the storage unit and transferring the coating liquid supplied from the storage unit onto at least one surface of a substrate transported in one direction; and at least one position adjusting roll disposed spaced apart from the storage unit and contacting at least one end of the width direction of the substrate to adjust the height of the substrate.

[0015] According to a second embodiment, in the first embodiment, the position adjustment roll may be in contact with one surface of the substrate onto which the coating liquid is transferred.

[0016] According to a third embodiment, in any one of the first to second embodiments, at least one position adjustment roll is included on each of the upstream and downstream sides of the conveying direction of the substrate, and the central axis of the upstream position adjustment roll and the central axis of the downstream position adjustment roll may be configured to be parallel to each other.

[0017] According to a fourth embodiment, in any one of the first to third embodiments, the position adjustment roll includes, depending on the position provided, a first position adjustment roll provided at a first position; a second position adjustment roll provided at a second position; a third position adjustment roll provided at a third position; and a fourth position adjustment roll provided at a fourth position; wherein the first position adjustment roll may be located at the left front, the second position adjustment roll may be located at the right front, the third position adjustment roll may be located at the left rear, and the fourth position adjustment roll may be located at the right rear.

[0018] According to the fifth embodiment, in the fourth embodiment, when the angle formed by the direction of the central axis of the first position adjustment roll and the direction of the central axis of the coating roll is -θ, the angle formed by the direction of the central axis of the second position adjustment roll and the direction of the central axis of the coating roll may be θ.

[0019] According to the sixth embodiment, in any one of the fourth to fifth embodiments, the direction of the central axis of the first position adjustment roll and the direction of the central axis of the third position adjustment roll may be parallel.

[0020] According to a seventh embodiment, in any one of the fourth to sixth embodiments, when the angle formed by the direction of the central axis of the first position adjustment roll and the direction of the central axis of the coating roll is -θ, a first position adjustment auxiliary roll is provided before the first position adjustment roll and the substrate come into contact and has an angle of -θ' with the direction of the central axis of the coating roll, and the size of θ' may be smaller than the size of θ.

[0021] According to the eighth embodiment, in any one of the first to seventh embodiments, a cleaning member for cleaning the surface of the position adjustment roll may be further provided.

[0022] According to the ninth embodiment, in any one of the first to eighth embodiments, the position adjustment roll may be surface treated.

[0023] According to the tenth embodiment, in any one of the first to ninth embodiments, the storage unit may further include a control unit that is provided on the outside of the storage unit and can control the position of the position control roll.

[0024] According to the eleventh embodiment, in any one of the first to tenth embodiments, a gas injection unit may be further included for injecting gas in the direction of the other side of the substrate in contact with the coating roll.

[0025] According to a twelfth embodiment, a method for manufacturing a separation membrane using the coating device of any one of the first to eleventh embodiments is provided, comprising: (S10) supplying a coating solution to a storage unit; (S20) adjusting the position of at least one position adjusting roll that contacts at least one end in the width direction of the substrate so that only at least a portion of one side of the substrate being transported in one direction contacts the coating roll; and (S30) transferring the coating solution contained in the storage unit onto one side of the substrate using the coating roll.

[0026] According to the 13th embodiment, in the 12th embodiment, in the step (S20), the position of the at least one position adjustment roll may be adjusted so that the tension of the substrate is 10 N to 200 N.

[0027] According to the 14th embodiment, in any one of the 12th to 13th embodiments, in the step (S20), the position of the at least one position adjustment roll may be moved over time.

[0028] According to the 15th embodiment, in any one of the 12th to 13th embodiments, in the step (S30), the area on which the coating liquid is transferred on one side of the substrate may be 50% to 99% based on 100% of the total area of ​​one side of the substrate.

[0029] According to the 16th embodiment, in any one of the 12th to 15th embodiments, in the step (S30), the ratio (Wc / W) of the width direction length (Wc) of the area where the coating liquid is transferred to the total width direction length (W) of the substrate may be 0.8 to 0.99.

[0030] According to the 17th embodiment, in any one of the 12th to 16th embodiments, the step (S30) may further include a step of spraying gas in the direction of the other surface of the substrate in contact with the coating roll.

[0031]

[0032] A coating device according to one embodiment of the present invention can control the position at which the coating liquid is transferred.

[0033] A coating device according to one embodiment of the present invention can provide a separation membrane having a uniformly formed coating layer.

[0034] A coating device according to one embodiment of the present invention can change the thickness and width of the coating layer along the longitudinal direction of the substrate.

[0035] A coating device according to one embodiment of the present invention can eliminate the phenomenon of quality deterioration occurring during drying by intentionally forming uncoated portions at both ends in the width direction of the substrate.

[0036] A coating device according to one embodiment of the present invention can minimize the use of coating liquid by changing the thickness and width of the coating layer to minimize the portion of the coating layer that is discarded during final slitting.

[0037] A method for manufacturing a separation membrane according to one embodiment of the present invention can control the position of a substrate to which a coating liquid is transferred.

[0038] A method for manufacturing a separator according to one embodiment of the present invention can provide a separator having a uniformly formed coating layer.

[0039] A method for manufacturing a separation membrane according to one embodiment of the present invention can change the thickness and width of the coating layer along the longitudinal direction of the substrate.

[0040] A method for manufacturing a separation membrane according to one embodiment of the present invention can eliminate the phenomenon of quality deterioration occurring during drying by intentionally forming an uncoated portion at both ends in the width direction of the substrate.

[0041] A method for manufacturing a separation membrane according to one embodiment of the present invention can minimize the use of a coating solution by changing the thickness and width of the coating layer to minimize the portion of the coating layer that is discarded during the final slitting.

[0042]

[0043] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of ​​the present invention together with the contents of the invention described above, and therefore the present invention should not be interpreted as being limited to matters described in such drawings.

[0044] Figure 1 schematically illustrates the structure of a coating device according to one embodiment of the present invention.

[0045] FIG. 2 is a schematic diagram illustrating a coating device according to one embodiment of the present invention and a method of transferring a coating solution onto at least one surface of a substrate using the same, as viewed in the x-axis direction.

[0046] Figure 3 schematically illustrates the structure of a coating device according to one embodiment of the present invention.

[0047] Figure 4 schematically illustrates the structure of a coating device according to one embodiment of the present invention.

[0048] Figure 5 schematically illustrates a position control roll and a substrate according to one embodiment of the present invention as viewed from the y-axis direction.

[0049] Figure 6 schematically illustrates the structure of a coating device according to one embodiment of the present invention.

[0050] Figure 7 schematically illustrates a position adjustment roll, a position adjustment auxiliary roll, and a substrate according to one embodiment of the present invention as viewed from the y-axis direction.

[0051] Figure 8a schematically illustrates the structure of a coating device according to one embodiment of the present invention.

[0052] Figure 8b schematically illustrates the structure of a coating device according to one embodiment of the present invention.

[0053] Figure 9 schematically illustrates the structure of a coating device according to one embodiment of the present invention.

[0054] Figure 10a schematically illustrates the structure of a coating device according to one embodiment of the present invention.

[0055] Figure 10b schematically illustrates the structure of a coating device according to one embodiment of the present invention.

[0056] Figure 11 schematically illustrates the structure of a coating device according to one embodiment of the present invention.

[0057] FIG. 12 is a schematic diagram illustrating a method of transferring a coating liquid onto at least one surface of a substrate using a coating device according to one embodiment of the present invention, as viewed in the y-axis direction.

[0058] FIG. 13 is a schematic diagram illustrating a coating device according to one embodiment of the present invention and a method of transferring a coating liquid onto at least one surface of a substrate using the same, as viewed in the x-axis direction.

[0059] Figure 14 schematically illustrates that a coating solution according to one embodiment of the present invention is transferred onto at least one surface of a substrate.

[0060]

[0061] 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.

[0062] 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.

[0063] Justice

[0064] Throughout this specification, when it is said that a part "includes" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0065]

[0066] <Coating device>

[0067] The present invention provides a coating device (10).

[0068] Figure 1 schematically illustrates the structure of a coating device (10) according to one embodiment of the present invention.

[0069] In one embodiment of the present invention, the coating device (10) of the present invention includes a storage unit (100) that contains a coating liquid; a coating roll (200) that is contained in the storage unit (100) and transfers the coating liquid (2) supplied from the storage unit (100) onto at least one surface of a substrate (1) that is transported in one direction; and at least one position adjusting roll (300) that is spaced apart from the storage unit (100) and contacts at least one end of the width direction of the substrate (1) to adjust the height of the substrate (1).

[0070] At this time, the substrate (1) is illustrated in FIG. 1 for reference, but should not be construed as limiting the coating device (10) of the present invention. The substrate (1) may be a porous polymer substrate for manufacturing a separator for a secondary battery. The coating solution (2) may be a slurry-state coating solution containing a binder polymer, inorganic particles, and a solvent. By transferring such a coating solution (2) onto at least one surface of the substrate (1), a separator including an inorganic coating layer on the porous polymer substrate can be manufactured. The coating device (10) of the present invention is thus suitable for use in separator coating.

[0071] Meanwhile, the direction in which the material (1) is transferred in the specification of the present invention may be the +y-axis direction in Fig. 1. Accordingly, in the specification of the present invention, the +y-direction is also referred to as the “transfer direction of the material.”

[0072] In addition, in the present specification, “upstream side in the transport direction of the substrate” or “upstream side” means before the substrate (1) comes into contact with the coating roll (200), and “downstream side in the transport direction of the substrate” or “downstream side” means after the substrate (1) comes into contact with the coating roll (200).

[0073]

[0074] FIG. 2 is a schematic drawing showing a coating device (10) according to one embodiment of the present invention and a method of transferring a coating solution (2) onto at least one surface of a substrate (1) using the same, as viewed in the x-axis direction.

[0075] In one embodiment of the present invention, the position adjustment roll (300) may be in contact with one surface of the substrate (1) on which the coating liquid (2) is transferred.

[0076] At this time, the coating solution (2) is illustrated in FIG. 2 for reference, but should not be construed as limiting the coating device (10) of the present invention.

[0077] In one embodiment of the present invention, the position adjustment roll (300) may be in contact with the surface of the substrate (1) to which the coating liquid (2) is transferred, and by adjusting the position of the position adjustment roll (300), the tension applied to the center of the width direction of the substrate (1) is reduced and the substrate (1) is sagged, so that the substrate (1) and the coating roll (200) come into contact. Referring to Fig. 2, at least one position adjustment roll (300) may be disposed on each of the upstream and downstream sides, and for example, may be disposed at both ends of the substrate (1) in the width direction on the upstream and downstream sides. At this time, since the position adjustment roll (300) is in contact with both ends of the substrate (1) in the width direction, the center of the substrate (1) in the width direction may be positioned closer to the coating roll (200) than the both ends of the substrate (1) in the width direction. By this principle, the coating liquid (2) can be transferred to the center of the width direction of the substrate (1).

[0078] Figure 3 schematically illustrates the structure of a coating device (10) according to one embodiment of the present invention.

[0079] In one embodiment of the present invention, at least one position adjusting roll (300) is included on the upstream and downstream sides of the conveying direction of the substrate (1), and the central axis of the upstream position adjusting roll (300) and the central axis of the downstream position adjusting roll (300) may be parallel to each other. Referring to FIG. 3, the dotted line illustrated on the position adjusting roll (300) indicates the direction of the central axis of the position adjusting roll (300), and a plurality of dotted lines illustrated in FIG. 3 are parallel to each other. When the directions of the central axes of the plurality of position adjusting rolls (300) are parallel to each other, after the coating liquid (2) is transferred onto at least one surface of the substrate (1), the coating liquid may not flow in any one direction, so that a coating layer can be formed more uniformly.

[0080] Meanwhile, as will be described later, in order for the directions of the central axes of the plurality of position adjustment rolls (300) to be parallel to each other, the direction of the central axis of the first position adjustment roll (310) and the direction of the central axis of the second position adjustment roll (320) may be parallel to each other. In addition, the direction of the central axis of the third position adjustment roll (330) and the direction of the central axis of the fourth position adjustment roll (340) may be parallel to each other.

[0081]

[0082] Figure 4 schematically illustrates the structure of a coating device (10) according to one embodiment of the present invention.

[0083] In one embodiment of the present invention, the position adjustment roll (300, 310, 320, 330, 340) includes, as shown in FIG. 4, a first position adjustment roll (310) provided at a first position; a second position adjustment roll (320) provided at a second position; a third position adjustment roll (330) provided at a third position; and a fourth position adjustment roll (340) provided at a fourth position, depending on the position provided, wherein the first position adjustment roll (310) means that it is located at the left front, the second position adjustment roll (320) means that it is located at the right front, the third position adjustment roll (330) means that it is located at the left rear, and the fourth position adjustment roll (340) may be located at the right rear.

[0084] In the present specification, "forward" means the upstream direction based on the direction in which the substrate (1) is transported to the coating device (10) (i.e., +y direction). In addition, in the present specification, "rear" means the direction after the coating liquid is transferred to the substrate by the coating roll based on the direction in which the substrate (1) is transported (i.e., +y direction).

[0085] In the present specification, “left” means the z-axis direction, i.e., the -x-axis direction when looking at the coating device from above, and “right” means the +x-axis direction.

[0086]

[0087] In one embodiment of the present invention, when the angle formed by the direction of the central axis of the first position adjustment roll (310) and the direction of the central axis of the coating roll (200) is -θ, the angle formed by the direction of the central axis of the second position adjustment roll (320) and the direction of the central axis of the coating roll (200) may be θ. Meanwhile, θ in which the "-" sign is omitted means +θ. That is, when it is assumed that the direction of the central axis of the coating roll (200) is horizontal, the direction of the central axis of the first position adjustment roll (310) may form an angle of -θ with the direction of the central axis of the coating roll (200), and the direction of the central axis of the second position adjustment roll (320) and the direction of the central axis of the coating roll (200) may form an angle of +θ. That is, the angle formed by the direction of the central axis of the first position adjustment roll (310) and the direction of the central axis of the coating roll (200) may be equal in size to, and opposite in direction to, the angle formed by the direction of the central axis of the second position adjustment roll (320) and the direction of the central axis of the coating roll (200).

[0088] In the present invention, the angle between the directions of the central axes can be derived through conventional vector calculation.

[0089] In this case, the center of the substrate (1) in the width direction can be further extended by the position adjustment roll (300, 310, 320, 330, 340), thereby making it easier for the center of the width direction to come into contact with the coating roll (200).

[0090] In one embodiment of the present invention, θ may be greater than 0° and less than or equal to 90°, greater than or equal to 2° and less than or equal to 45°, greater than or equal to 4° and less than or equal to 30°, greater than or equal to 6° and less than or equal to 25°, or greater than or equal to 8° and less than or equal to 15°. In the present invention, when θ is a negative number, when viewed toward the y-axis, it is rotated clockwise by the magnitude of θ, and when θ is a positive number, it is rotated counterclockwise by the magnitude of θ.

[0091]

[0092] FIG. 5 schematically illustrates a position adjustment roll (300, 310, 320) and a substrate (1) according to one embodiment of the present invention as viewed from the y-axis direction.

[0093] Specifically, (a) of FIG. 5 is a case where the angle formed by the direction of the central axis of the first position adjustment roll (310) and the direction of the central axis of the coating roll and the angle formed by the direction of the central axis of the second position adjustment roll (320) and the direction of the central axis of the coating roll are 0°, and (b) of FIG. 5 is a case where the angle formed by the direction of the central axis of the first position adjustment roll (310) and the direction of the central axis of the coating roll is -θ, and the angle formed by the direction of the central axis of the second position adjustment roll (320) and the direction of the central axis of the coating roll is θ. At this time, the center of the width direction of the base material (1) of FIG. 5 (b) is further extended toward the coating roll (200) than the base material (1) of FIG. 5 (a), so that it can be easier to contact the coating roll (200).

[0094]

[0095] Meanwhile, in one embodiment of the present invention, the direction of the central axis of the first position adjustment roll (310) and the direction of the central axis of the third position adjustment roll (330) may be parallel. For example, in FIG. 4, the angle formed by the direction of the central axis of the first position adjustment roll (310) and the direction of the central axis of the coating roll (200) may be -θ, and the angle formed by the direction of the central axis of the third position adjustment roll (330) and the direction of the central axis of the coating roll (200) may be -θ. In this case, the coating solution (2) can be stably transferred onto at least one surface of the substrate (1).

[0096]

[0097] Figure 6 schematically illustrates the structure of a coating device (10) according to one embodiment of the present invention.

[0098] Figure 7 schematically illustrates a position adjustment roll (310, 320), a position adjustment auxiliary roll (311, 321), and a substrate (1) according to one embodiment of the present invention.

[0099] The coating device (10) further includes a first position adjustment auxiliary roll (311) which is provided before the first position adjustment roll (310) and the substrate come into contact with each other, that is, further in the upstream direction, and has an angle of -θ' with the direction of the central axis of the coating roll (200), when the angle formed by the direction of the central axis of the first position adjustment roll (310) and the direction of the central axis of the coating roll (200) is -θ, and a second position adjustment auxiliary roll (321) which is provided before the second position adjustment roll (320) and the substrate come into contact with each other, that is, further in the upstream direction, and has an angle of θ' with the direction of the central axis of the coating roll (200), and the size of θ' may be smaller than the size of θ. The magnitudes of the above θ' and the above θ can be compared as absolute values.

[0100] In this way, when the first position-adjusting auxiliary roll (311) is further included, when the substrate (1) approaches the coating device (10), the center portion in the width direction of the substrate (1) can be induced to sequentially stretch downwards (i.e., in the -z direction). Specifically, as illustrated in FIG. 7, it can be seen that the extent to which the center portion in the width direction of the substrate (1) is stretched by the first position-adjusting auxiliary roll (311) and the second position-adjusting auxiliary roll (321) is greater than the extent to which the center portion in the width direction of the substrate (1) is stretched by the first position-adjusting auxiliary roll (310) and the second position-adjusting auxiliary roll (320). Accordingly, when the first position-adjusting auxiliary roll (311) and the second position-adjusting auxiliary roll (321) are further included, when the substrate (1) approaches the coating device (10), the center portion in the width direction of the substrate (1) can be induced to sequentially stretch downwards (i.e., in the -z-axis direction).

[0101] In one embodiment of the present invention, the coating device (10) may or may not be provided with a plurality of first position adjustment auxiliary rolls (311) and second position adjustment auxiliary rolls (321).

[0102] In one embodiment of the present invention, the third position adjustment roll (320) may have an angle formed by the direction of the central axis of the third position adjustment roll (330) and the direction of the central axis of the coating roll (200) of -θ or 0°. In this case, θ may be greater than 0° and less than 90°.

[0103] Fig. 8a schematically illustrates the structure of a coating device (10) according to one embodiment of the present invention. Fig. 8b schematically illustrates the structure of a coating device (10) according to one embodiment of the present invention.

[0104]

[0105] In one embodiment of the present invention, the position adjustment roll (300) has a cylindrical shape and can rotate when the substrate is transported, so a cleaning member (500) for cleaning the surface of the position adjustment roll (300) may be further provided. For example, there is no particular limitation on the position of the cleaning member (500) as long as the position adjustment roll (300) does not come into contact with the substrate (1) or does not obstruct the transport of the substrate (1). For example, the cleaning member (500) may be provided so as to come into contact with the lower portion of the position adjustment roll (300).

[0106] In one embodiment of the present invention, the cleaning member (500) is not limited in type. The cleaning member (500) may be, for example, a brush-type cleaning member, a scraper-type cleaning member, an air jet-type cleaning member, a liquid spray-type cleaning member, or a combination thereof.

[0107] In one embodiment of the present invention, the cleaning member (500) may be provided on the position adjustment roll (300) located on the downstream side. For example, the coating device (10) according to one example of the present invention may further include the cleaning member (500) on the position adjustment rolls (330, 340) located on the downstream side, as illustrated in FIG. 8A. In this case, after the coating liquid is transferred to the substrate, if any residue exists on the uncoated portion formed on both ends in the width direction of the substrate, it is possible to remove the residue, and the phenomenon of the end of the coating layer flowing down can also be suppressed or controlled.

[0108] In one embodiment of the present invention, the position adjustment roll (300) may further include an operating sensor unit (not shown). Accordingly, when a plurality of position adjustment rolls (300) are provided, the rotational speeds of each position adjustment roll can be mutually synchronized, or their angles can be remotely controlled. In this case, the position adjustment roll (300) may be rotated by a motor drive unit (not shown), etc.

[0109] In one embodiment of the present invention, the position adjustment roll (300) may further include a non-contact measurement sensor (not shown) capable of measuring the thickness of the coating liquid transferred onto the substrate. When the position adjustment roll (300) is cylindrical, the non-contact measurement sensor may be provided at a position perpendicular to the transport direction of the substrate to measure the thickness of the coating liquid.

[0110] In one embodiment of the present invention, the position adjustment roll (300) may be surface-treated. For example, the position adjustment roll (300) may be surface-treated by sandblasting, rubber coating, or micro-roughening to improve friction with the substrate (1). By using the surface treatment as described above, it is possible to move or expand the substrate (1) in the width direction using the position adjustment roll (300). This position adjustment roll may be placed in either the upstream or downstream position.

[0111] In one embodiment of the present invention, the surface-treated position-adjusting roll may be provided together with the position-adjusting roll equipped with the aforementioned cleaning member or the position-adjusting auxiliary roll equipped with the cleaning member. For example, referring to FIG. 8b, the coating device (10) may be provided with the surface-treated position-adjusting roll (330, 340), and further provided with a position-adjusting auxiliary roll (331, 341) equipped with a cleaning member on the downstream side. In this case, although the surface-treated component may be partially transferred onto the substrate (1) through the surface-treated position-adjusting roll (330, 340), the position-adjusting auxiliary roll (331, 341) equipped with the cleaning member that is arranged thereafter removes this, thereby preventing contamination of the uncoated portion of the substrate (1). Meanwhile, at this time, the position-adjusting auxiliary rolls (331, 341) may be respectively horizontal to the coating roll.

[0112]

[0113] Figure 9 schematically illustrates the structure of a coating device (10) according to one embodiment of the present invention.

[0114] In one embodiment of the present invention, the coating device (10) is provided on the outside of the storage unit (100) and may further include a control unit (310a, 320a, 330a, 340a) capable of controlling the position of the position control roll (300, 310, 320, 330, 340). Specifically, the coating device (10) may further include an adjustment unit (310a) of a first position adjustment roll that can adjust the position of the first position adjustment roll (310), the coating device (10) may further include an adjustment unit (320a) of a second position adjustment roll that can adjust the position of the second position adjustment roll (320), the coating device (10) may further include an adjustment unit (330a) of a third position adjustment roll that can adjust the position of the third position adjustment roll (330), and the coating device (10) may further include an adjustment unit (340a) of a fourth position adjustment roll that can adjust the position of the fourth position adjustment roll (340).

[0115] In one embodiment of the present invention, the control unit (310a, 320a, 330a, 340a) may be fixed to, for example, a storage unit (100), and may be moved in the x-axis direction and the z-axis direction by a piston device or the like (not shown) to control the position of the position control roll (300, 310, 320, 330, 340), thereby controlling the position of the substrate (1).

[0116] In one embodiment of the present invention, the control unit (310a, 320a, 330a, 340a) moves in the x-axis direction and the z-axis direction by a piston device (not shown) over time to control the position of the position control roll (300, 310, 320, 330, 340), thereby controlling the position of the substrate (1) and controlling the amount of coating liquid transferred in the longitudinal direction of the substrate (i.e., the y-axis direction).

[0117] In one embodiment of the present invention, the coating device (10) may further include a measuring device (not shown) for measuring the properties of the coating liquid, for example, the viscosity of the coating liquid, thereby measuring the properties of the coating liquid, and adjusting the position of the position adjusting roll (300, 310, 320, 330, 340) through the adjusting unit (310a, 320a, 330a, 340a) based on the measured data, thereby controlling the amount of the coating liquid transferred onto the substrate (1).

[0118]

[0119] Figure 10a schematically illustrates the structure of a coating device (10) according to one embodiment of the present invention.

[0120] In one embodiment of the present invention, the coating device (10) may further include a gas injection unit (400) that injects gas in the direction of the other side of one side of the substrate (1) that comes into contact with the coating roll (200). By having the gas injection unit (400) inject gas in the direction of the other side of the substrate, one side of the substrate (1) can more easily come into contact with the coating roll (200).

[0121] Figure 10b schematically illustrates the structure of a coating device (10) according to one embodiment of the present invention.

[0122] In one embodiment of the present invention, the coating device (10) may further include a backup roll (410) that contacts the other side of one side of the substrate (1) that contacts the coating roll (200). The backup roll (410) contacts the substrate (1) in the other side direction, so that one side of the substrate (1) can more easily contact the coating roll (200).

[0123] In one embodiment of the present invention, the position of the backup roll (410) can be adjusted in consideration of the position of the position adjustment roll (300) and the tension of the substrate (1).

[0124] In one embodiment of the present invention, the x-axis diameter of the backup roll (410) may be substantially the same as the diameter of the coating roll (200).

[0125]

[0126] Fig. 11 schematically illustrates the structure of a coating device (10) according to one embodiment of the present invention, and Fig. 12 schematically illustrates transferring a coating solution onto at least one surface of a substrate (1) using the device (10) as viewed from the y-axis direction.

[0127] In one embodiment of the present invention, the position of the position adjustment roll (310, 320) in contact with one of the ends of the substrate (1) can be moved in the +z-axis direction so that the coating liquid is not transferred onto the substrate (1) in contact with the direction of the position adjustment roll (310, 320).

[0128] Meanwhile, in one embodiment of the present invention, the position of the position adjustment roll (310, 320) can be adjusted so as not to differ from the position of the position adjustment roll (330, 340) in contact with the other end. In this case, the center of the width direction of the substrate (1) does not stretch, but the substrate (1) in contact with the position adjustment roll (310, 320) in contact with one of the ends moves away from the coating roll (200), so that the position at which the coating liquid is transferred can be adjusted.

[0129]

[0130] FIG. 13 is a schematic diagram illustrating a coating device according to one embodiment of the present invention and a method of transferring a coating liquid onto at least one surface of a substrate using the same, as viewed in the x-axis direction.

[0131] In one embodiment of the present invention, the storage unit (100) may have one side open as shown in FIG. 2, or the storage unit (100) may be sealed as shown in FIG. 13. When the storage unit (100) is sealed, vaporization of volatile components included in the coating solution can be prevented, and mixing of foreign substances can be further prevented.

[0132] In one embodiment of the present invention, the storage unit (100) may further include a nozzle (not shown) for supplying a coating liquid to the lower portion.

[0133] In one embodiment of the present invention, the coating roll (200) may be a gravure roll, a reverse gravure roll, an anilox roll, a doctor roll, a pattern roll, or the like.

[0134]

[0135] <Method for manufacturing a separation membrane>

[0136] The present invention provides a method for manufacturing a separation membrane.

[0137] A method for manufacturing a separation membrane according to one embodiment of the present invention comprises the steps of: (S10) supplying a coating solution to a storage unit using the coating device (10) described above; (S20) adjusting the position of at least one position adjusting roll that contacts at least one end in the width direction of the substrate so that only at least a portion of one side of the substrate being transported in one direction comes into contact with the coating roll; and (S30) transferring the coating solution contained in the storage unit onto one side of the substrate using the coating roll.

[0138] Below, we will look at each step in detail.

[0139] First, the method for manufacturing the separation membrane of the present invention supplies a coating solution to a storage unit (100) (step S10). The coating solution (2) can be prepared by adding a binder polymer and inorganic particles to a solvent and mixing them. The solids content of the coating solution can be in the range of 5 to 40 wt% relative to 100 wt% of the coating solution.

[0140]

[0141] In one embodiment of the present invention, the binder polymer can improve the mechanical properties such as flexibility and elasticity of the finally formed separator, and faithfully performs the role of a binder that connects and stably fixes inorganic particles, thereby contributing to preventing deterioration of the mechanical properties of the separator. The glass transition temperature (T) of the binder polymer g ) can exist within the range of -200℃ to 200℃.

[0142] In addition, the binder polymer does not necessarily need to have ion-conducting ability, but if a polymer having ion-conducting ability is used, the performance of the lithium secondary battery can be further improved. Therefore, the binder polymer may have a high dielectric constant as much as possible. In fact, since the degree of salt dissociation in the electrolyte depends on the dielectric constant of the electrolyte solvent, the higher the dielectric constant of the binder polymer, the better the degree of salt dissociation in the electrolyte. The dielectric constant of the binder polymer can be used in the range of 1.0 to 100 (measurement frequency = 1 kHz), and in particular, can be 10 or more.

[0143] In one embodiment of the present invention, the binder polymer can exhibit a high degree of swelling by being gelled when impregnated with a liquid electrolyte. The solubility index of the binder polymer, i.e., the Hildebrand solubility parameter, is 15 to 45 MPa. 1 / 2 or 15 to 25 MPa 1 / 2 and 30 to 45 MPa 1 / 2 It may be within a range. In one embodiment of the present invention, when hydrophilic polymers having a large number of polar groups are used more than hydrophobic polymers such as polyolefins, the solubility index range described above can be satisfied. In this case, when the solubility index is below the lower limit or exceeds the upper limit of the above-described range, swelling by a typical battery liquid electrolyte may be difficult.

[0144] In one embodiment of the present invention, the inorganic particles are filled and in contact with each other and are bound to each other by the binder polymer, thereby forming an interstitial volume between the inorganic particles, and the interstitial volume between the inorganic particles may become an empty space to form pores. The binder polymer may attach the inorganic particles to each other so that the particles can maintain a state of being bound to each other, for example, the binder polymer may connect and fix the inorganic particles. In addition, the pores of the separator are pores formed by the interstitial volume between the inorganic particles becoming an empty space, and this may be a space defined by the inorganic particles substantially meeting each other in a closed packed or densely packed structure by the inorganic particles.

[0145] In one embodiment of the present invention, any binder polymer commonly used in the relevant technical field can be used without limitation. The above binder polymers include, for example, polymethylmethacrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, carboxyl methyl Cellulose (carboxyl methyl cellulose), or two or more of these.

[0146] At this time, the binder polymer may be a particulate binder or a soluble binder. The particulate binder is a binder polymer that does not dissolve in a solvent. The binder polymer is a soluble binder, meaning that the binder polymer dissolves in a solvent. At this time, the solvent may be an aqueous solvent or an organic solvent.

[0147]

[0148] In one embodiment of the present invention, the inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles that can be used in the present invention can be used within the operating voltage range of the applied electrochemical device (e.g., Li / Li). + There are no particular limitations as long as no oxidation and / or reduction reaction occurs at a voltage of 0 to 5 V as a standard. In particular, when using inorganic particles with a high dielectric constant as inorganic particles, it can contribute to increasing the degree of dissociation of electrolyte salts, such as lithium salts, in the liquid electrolyte, thereby improving the ionic conductivity of the electrolyte.

[0149] For the reasons mentioned above, it is preferable that the inorganic particles include high-k inorganic particles having a dielectric constant of 5 or more, preferably 10 or more. Non-limiting examples of inorganic particles having a dielectric constant of 5 or more include BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT, 0 <x<1, 0<y<1), Pb(Mg 1 / 3 Nb 2 / 3 )O3-PbTiO3(PMN-PT), hafnia (HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, SiO2, Y2O3, Al2O3, SiC, TiO2 or mixtures thereof.

[0150] In addition, inorganic particles having lithium ion transfer capability, i.e., inorganic particles containing lithium element but having the function of transferring lithium ions without storing lithium, can be used. Non-limiting examples of inorganic particles having lithium ion transfer capability include lithium phosphate (Li3PO4), lithium titanium phosphate (Li). x Ti y (PO4)3, 0 < x <2, 0 < y < 3), lithium aluminum titanium phosphate (Li x Al y Ti z(PO4)3, 0 < x < 2, 0 < y < 1, 0 < z < 3), 14Li2O-9Al2O3-38TiO2-39P2O5, etc. (LiAlTiP) x O y Series Glass (0 <x < 4, 0 < y < 13), 리튬란탄티타네이트(Li x La y TiO3, 0 < x < 2, 0 < y < 3), Li 3.25 Ge 0.25 P 0.75 Lithium germanium thiophosphate (Li) such as S4 x Ge y P z S w , 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), lithium nitride (Li 3 N ), etc. x N y , 0 < x <4, 0 < y < 2), SiS2 series glasses such as Li3PO4-Li2S-SiS2 (Li x Si y S z , 0 < x < 3, 0 <y < 2, 0 < z < 4), LiI-Li2S-P2S5등과 같은 P2S5계열 글래스(Li x P y S z , 0 < x < 3, 0< y < 3, 0 < z < 7) or mixtures thereof.

[0151] In addition, the average particle diameter (D) of inorganic particles (single particles) 50 ) has no special limitations, but in order to form a coating layer of uniform thickness and have an appropriate porosity, it is preferably in the range of 0.1 ㎛ to 1.5 ㎛. If the average particle diameter of the inorganic particles is less than the lower limit, dispersibility may be reduced, and if it exceeds the upper limit, the thickness of the inorganic coating layer formed may increase.

[0152] In one embodiment of the present invention, the inorganic particles may be included in a range of 10% by weight to 90% by weight based on 100% by weight of the solid content of the coating liquid.

[0153]

[0154] In one embodiment of the present invention, the solvent may be an aqueous solvent or an oil-based solvent.

[0155] In one embodiment of the present invention, the aqueous solvent may be water or an aqueous solvent containing water. Furthermore, when drying speed and temperature are limited, methanol, ethanol, isopropyl alcohol, or the like, which have a lower boiling point than water, may be used together.

[0156] In one embodiment of the present invention, the organic solvent is cyclic aliphatic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as toluene, xylene and ethylbenzene; ketones such as acetone, ethyl methyl ketone, diisopropyl ketone, cyclohexanone, methylcyclohexane and ethylcyclohexane; chlorinated aliphatic hydrocarbons such as methylene chloride, chloroform and carbon tetrachloride; esters such as ethyl acetate, butyl acetate, γ-butyrolactone and ε-caprolactone; acylonitrile such as acetonitrile and propionitrile; ethers such as tetrahydrofuran and ethylene glycol diethyl ether; alcohols such as methanol, ethanol, isopropanol, ethylene glycol and ethylene glycol monomethyl ether; amides such as N-methylpyrrolidone and N,N-dimethylformamide. , and the organic solvent may include acetone in consideration of the advantage in the drying process.

[0157] In one embodiment of the present invention, the organic solvent may be used alone, or a mixed solvent of two or more thereof may be used. Among these, solvents with low boiling points and high volatility are particularly preferred, as they can be removed in a short period of time and at low temperatures. Specifically, acetone, toluene, cyclohexanone, cyclopentane, tetrahydrofuran, cyclohexane, xylene, or N-methylpyrrolidone, or a mixed solvent thereof, are preferred.

[0158]

[0159] Thereafter, the positions of a plurality of position adjustment rolls that contact both ends in the width direction of the substrate are adjusted so that only at least a portion of one side of the substrate being transported in one direction comes into contact with the coating roll (step (S20)).

[0160]

[0161] In one embodiment of the present invention, the method for adjusting the position of the position adjustment roll can be adjusted by an adjustment unit (310a, 320a, 330a, 340a) according to one embodiment of the present invention.

[0162]

[0163] In one embodiment of the present invention, in the step (S20), the position of at least one position adjustment roll may be adjusted so that the tension of the substrate (1) is 10 N to 200 N. At this time, the tension can be measured at the center position in the width direction of the substrate (1) using a conventional tension measuring device.

[0164]

[0165] In one embodiment of the present invention, the step (S20) may include a step of adjusting the position of a position adjustment roll (300) that comes into contact with one of the two ends of the substrate (1). In this case, the position at which the coating liquid is transferred among the substrate (1) can be adjusted.

[0166]

[0167] In one embodiment of the present invention, in the step (S20), the positions of the plurality of position adjustment rolls may be moved over time. For example, the plurality of position adjustment rolls (300, 310, 320, 330, 340) may be adjusted by moving in the x-axis direction and the z-axis direction by a piston device (not shown) over time of the adjustment unit (310a, 320a, 330a, 340a). As a result, the amount of coating liquid transferred can be adjusted in the longitudinal direction (i.e., y-axis direction) of the substrate (1) to which the coating liquid (2) is transferred.

[0168]

[0169] Thereafter, (S30) the coating liquid (2) contained in the storage unit (100) is transferred onto one side of the substrate (1) using the coating roll (200). The method of coating the coating liquid (2) onto one side of the substrate (1) can preferably be performed by a roll coating method.

[0170]

[0171] In one embodiment of the present invention, in the step (S30), the area on one side of the substrate to which the coating liquid is transferred may be 50% to 99%, or 60% to 90%, of the total area of ​​one side of the substrate. When the area on which the coating liquid is transferred satisfies the above-described range, the quality of the separation membrane can be maintained at a better level.

[0172]

[0173] Figure 14 is a drawing showing that a coating solution (2) according to one embodiment of the present invention is transferred onto at least one surface of a substrate (1).

[0174] In one embodiment of the present invention, in the step (S30), the ratio (Wc / W) of the width direction length (Wc) of the area where the coating liquid is transferred to the total width direction length (W) of the substrate may be 0.8 to 0.99. When the ratio (Wc / W) of the width direction length (Wc) of the area where the coating liquid is transferred to the total width direction length (W) of the substrate satisfies the above-described range, an uncoated portion can be formed to eliminate the phenomenon of quality deterioration occurring during drying, and the coating layer can be minimized in the portion to be discarded during the final slitting, thereby minimizing the use of the coating liquid.

[0175]

[0176] In one embodiment of the present invention, the step (S30) may further include a step of spraying gas in the direction of the other side of one side of the substrate (1) in contact with the coating roll (200). When the gas is sprayed in the direction of the other side of one side of the substrate (1) in contact with the coating roll (200), the contact between the substrate and the coating roll (200) is more effective, and by controlling the amount, intensity, and time of gas spraying, the amount of coating liquid transferred to the coating roll (200) can be controlled.

Claims

1. A storage unit containing a coating liquid; A coating roll that is accommodated in the storage unit and transfers a coating liquid supplied from the storage unit onto at least one side of a substrate that is transported in one direction; and A coating device comprising at least one position adjusting roll arranged spaced apart from the storage unit and contacting at least one end of the width direction of the substrate to adjust the height of the substrate.

2. In claim 1, A coating device characterized in that the above position adjustment roll comes into contact with one surface of the above substrate to which the coating liquid is transferred.

3. In claim 1, It includes at least one position adjustment roll on each of the upstream and downstream sides of the transport direction of the above description, A coating device characterized in that the central axis of the upstream position adjustment roll and the central axis of the downstream position adjustment roll are configured to be parallel to each other.

4. In claim 1, The above position adjustment roll is equipped with, A first position adjustment roll provided at the first position; A second position adjustment roll provided at the second position; A third position adjustment roll provided at the third position; and Includes a fourth position adjustment roll provided at the fourth position; The above first position adjustment roll is located on the left front side, The above second position adjustment roll is located on the right front side, The above third position adjustment roll is located on the left rear side, A coating device characterized in that the fourth position adjustment roll is located at the right rear.

5. In claim 4, A coating device characterized in that when the angle formed by the direction of the central axis of the first position adjustment roll and the direction of the central axis of the coating roll is -θ, the angle formed by the direction of the central axis of the second position adjustment roll and the direction of the central axis of the coating roll is θ.

6. In claim 4, A coating device characterized in that the direction of the central axis of the first position adjustment roll and the direction of the central axis of the third position adjustment roll are parallel.

7. In claim 4, When the angle formed by the direction of the central axis of the first position adjustment roll and the direction of the central axis of the coating roll is -θ, a first position adjustment auxiliary roll is provided before the first position adjustment roll and the substrate come into contact and has an angle of -θ' with the direction of the central axis of the coating roll, A coating device characterized in that the size of the above θ' is smaller than the size of θ.

8. In claim 1, A coating device characterized in that it further comprises a cleaning member for cleaning the surface of the position adjustment roll.

9. In claim 1, A coating device characterized in that the above position adjustment roll is surface treated.

10. In claim 1, A coating device characterized in that it further includes a control unit provided on the outside of the storage unit and capable of controlling the position of the position control roll.

11. In claim 1, A coating device characterized by further comprising a gas injection unit that injects gas in the direction of the other surface of the substrate in contact with the coating roll.

12. A method for manufacturing a separation membrane using the coating device of claim 1, (S10) Step of supplying the coating solution to the storage unit; (S20) A step of adjusting the position of at least one position adjusting roll that contacts at least one end in the width direction of the substrate so that only at least a portion of one side of the substrate being transported in one direction comes into contact with the coating roll; and (S30) A method for manufacturing a separation membrane, comprising a step of transferring a coating solution contained in the storage unit onto one surface of the substrate using the coating roll.

13. In claim 12, In the above step (S20), A method for manufacturing a separation membrane, characterized in that the position of at least one position adjustment roll is adjusted so that the tension of the above-mentioned material is 10 N to 200 N.

14. In claim 12, In the above step (S20), A method for manufacturing a separation membrane, characterized in that the position of at least one position adjustment roll is moved over time.

15. In claim 12, In the above step (S30), A method for manufacturing a separation membrane, characterized in that the area on which the coating liquid is transferred on one side of the substrate is 50% to 99% of the total area of ​​one side of the substrate.

16. In claim 12, In the above step (S30), A method for manufacturing a separation membrane, characterized in that the ratio (Wc / W) of the width direction length (W) of the area where the coating liquid is transferred to the total width direction length (W) of the above-mentioned substrate is 0.8 to 0.

99.

17. In claim 12, In the above step (S30), A method for manufacturing a separation membrane, characterized in that it further includes a step of spraying gas in the direction of the other surface of the substrate in contact with the coating roll.

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