Electrode sheet drying device and drying method

Abstract

A drying apparatus according to an embodiment of the present invention comprises: a solvent supply unit for spraying a solvent onto an uncoated region, the solvent supply unit includes a main flow path sequentially passing through N solvent ejection nozzles disposed along a width direction (TD), a sub-flow path branching from the main flow path, and a valve at a branching point thereof, the valve may be configured to block the main flow path by operating the valve, and the solvent is allowed to flow into the sub-flow path. In the drying apparatus according to an embodiment of the present invention, the valve allows the solvent to bypass the sub-flow path, so that supply of the solvent to some of the plurality of solvent ejection nozzles that do not require solvent ejection can be prevented. Accordingly, there is an effect that there is no need to change the design of the solvent supply unit according to the type of electrode coating.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2023-0031025 filed on March 9, 2023.

[0002] The present invention relates to a drying apparatus and a drying method for an electrode sheet, and more particularly, to a drying apparatus and a method for an electrode sheet configured to control solvent supply to a solvent jet nozzle according to a change in a coating pattern of the electrode sheet. Background Art

[0003] Generally, a lithium secondary battery includes a positive electrode, a negative electrode, and an electrolyte material interposed therebetween, and is classified into a lithium ion battery, a lithium polymer battery, etc., depending on which positive electrode active material and negative electrode active material are used.

[0004] Electrodes of these lithium secondary batteries may be formed by coating a negative electrode active material or a positive electrode active material on a current collector such as an aluminum or copper sheet, mesh, film, or foil and then drying them in an oven.

[0005] The electrode sheet supplied by moving into the oven may include a coated portion coated with the electrode slurry and an uncoated portion not coated with the electrode slurry, and during the drying process, the solvent in the electrode slurry of the coated portion evaporates by drying, and the electrode slurry of the coated portion shrinks accordingly. During the drying process, the shrinkage force of the electrode slurry of the coated portion may act as a stress on the current collector of the uncoated portion, causing wrinkles and cracks. Due to the high capacity and high load tendency of the battery, the increase in the temperature of the hot air further exacerbates this phenomenon.

[0006] Korean Patent Publication No. 10-2021-0015278 discloses a technology that cools the temperature inside the oven by spraying moisture into the oven to minimize the occurrence of damage such as disembedding and cracking of the electrode due to overdrying, thereby maintaining a stable level of dryness of the electrode to be dried. However, in the above technology, a moisture spray nozzle is installed in the pipeline to supply moisture in the form of mist to the hot air supplied to the inside of the oven using the pipeline, and since the moisture is not directly sprayed onto the uncoated part, there is a limitation in the occurrence of cracks in the uncoated part. Therefore, a technology of spraying moisture onto the uncoated part by installing a moisture spray nozzle inside the oven has been attempted.

[0007] Figure 1 A conventional electrode sheet drying device having a moisture spray nozzle installed in an oven is illustrated, Figure 2 Illustrated Figure 1 The conventional method of supplying moisture by the moisture injection nozzle shown in Figure 3The problems with conventional methods of supplying moisture are illustrated.

[0008] Referring to these figures, a plurality of moisture injection nozzles 21 are installed in the oven 30, which are spaced apart a certain distance along the width direction (TD, Y direction) of the electrode sheet 10, and are configured to supply moisture S from the top side of the electrode sheet 10 toward the electrode sheet 10. In addition, the main flow path 23 passes through the plurality of moisture injection nozzles 21, and the pump 26 is configured to supply the solvent stored in the storage tank (not shown) to the plurality of moisture injection nozzles 21 through the main flow path 23.

[0009] In addition, when applying the electrode slurry, it can be Figure 1 It is coated as shown in FIG. 1 so that the coated portion 12 and the uncoated portion 11 appear alternately along the width direction (Y direction) of the electrode sheet, or as shown in FIG. Figure 3 It is coated as shown in such that the uncoated portions 11 are located at both edges in the width direction of the electrode sheet and the coated portion 12 is located in the center.

[0010] However, conventional moisture supply methods are not suitable for such changes in coating shape. Figure 1 The coating device is suitable for electrode sheets having alternating coated portions 12 and uncoated portions 11, but for Figure 3 In the electrode sheet shown in FIG. 1 having only the uncoated portions 11 located on both edges, the coating device is forced to spray water on the central coated portion 12 which does not need to be sprayed with water.

[0011] Therefore, it is necessary to develop a drying device and a drying method for electrode sheets that can improve these problems. Summary of the invention

[0012] Technical issues

[0013] An object of the present invention is to provide a drying device and a drying method for an electrode sheet, wherein the drying device for an electrode sheet includes a plurality of solvent spray nozzles, some of which include a solvent supply unit capable of cutting off the solvent supply in response to a change in a coating shape of the electrode sheet.

[0014] Technical Solution

[0015] According to an exemplary embodiment of the present invention, the present invention provides an electrode sheet drying device, which includes: an oven, the oven forming an internal space for drying an electrode sheet, on which an electrode slurry is coated on a current collector; and a solvent supply unit, the solvent supply unit being configured to spray a solvent onto the electrode sheet traveling in the oven.

[0016] According to an exemplary embodiment, the solvent supply unit may include: N solvent injection nozzles, which are installed in the oven, arranged in plurality along the width direction TD of the electrode sheet, and spray the solvent toward the uncoated portion of the electrode sheet; a storage tank, which stores the solvent to be supplied to the solvent injection nozzles; a main flow path, which is connected to the storage tank and passes through the N solvent injection nozzles in sequence; one or more sub-flow paths, which branch off from the main flow path and then merge into the main flow path; and a valve, which is located at a branch point between the main flow path and the sub-flow path, and connects and blocks the main flow path.

[0017] According to an exemplary embodiment, the valve blocks the main flow path in an “open” state to allow the solvent to flow into the sub-flow path, and connects the main flow path in a “closed” state to allow the solvent to flow into the main flow path.

[0018] According to an exemplary embodiment, the number of the valves may correspond to the number of the sub-flow paths.

[0019] According to an exemplary embodiment, the number of the sub-flow paths may be two or more.

[0020] According to an exemplary embodiment, the number of the sub-flow paths may be N-2 or less.

[0021] According to an exemplary embodiment, one sub flow path may be configured to bypass one solvent injection nozzle.

[0022] According to an exemplary embodiment, the valves are two or more, and each valve may be configured to be independently controllable to perform an on-off operation.

[0023] According to an exemplary embodiment, a first solvent injection nozzle disposed at one outermost portion in the electrode sheet width direction TD and an Nth solvent injection nozzle disposed at the other outermost portion in the electrode sheet width direction TD may be configured to be supplied with the solvent only through the main flow path.

[0024] According to an exemplary embodiment, the solvent supply unit may further include a pump for supplying the solvent stored in the storage tank to the solvent injection nozzle via a main flow path.

[0025] According to an exemplary embodiment, the solvent spray nozzle may be provided in plural in a traveling direction (MD) of the electrode sheet.

[0026] An electrode sheet drying device according to an exemplary embodiment may further include: a hot air supply unit, which is used to supply hot air to the electrode sheet traveling in the oven, wherein the hot air supply unit may include: a heat exchanger, which heats the supplied external air; a hot air injection nozzle, which is installed in the oven, and the hot air injection nozzle is configured to blow hot air toward the electrode sheet; a blower fan, which is used to supply the external air heated by the heat exchanger to the hot air injection nozzle through a pipe connected to the internal space of the oven; and a damper, which is installed in the pipe to adjust the hot air supply.

[0027] According to another exemplary embodiment, the present invention provides an electrode sheet drying method, which includes the following steps: placing the electrode sheet in an oven and inputting position information of an uncoated portion that will not be sprayed with a solvent; a valve operation process, based on the input information, operating a valve located at a branching point between a main flow path passing through N solvent spray nozzles arranged in plurality along a width direction TD of the electrode sheet and a sub-flow path branched from the main flow path; and supplying a solvent and spraying the solvent through the solvent spray nozzle.

[0028] The electrode sheet drying method according to the exemplary embodiment enables control of solvent supply to at least one solvent spray nozzle through a valve operation process.

[0029] In an exemplary embodiment, the valve blocks the main flow path in an “open” state to allow the solvent to flow into the sub-flow path, and the valve connects the main flow path in a “closed” state to allow the solvent to flow into the main flow path.

[0030] In an exemplary embodiment, the number of the sub-flow paths may be two or more.

[0031] In an exemplary embodiment, each of the sub-flow paths may be configured to bypass one solvent injection nozzle.

[0032] Beneficial Effects

[0033] In the drying device according to the exemplary embodiment of the present invention, the solvent supplied to the solvent injection nozzle through the main flow path can be redirected to the sub-flow path, thereby preventing the supply of solvent to some of the plurality of solvent injection nozzles that do not require solvent injection. Therefore, it is not necessary to change the design of the solvent supply unit according to the coating type of the electrode sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1is a diagram illustrating a conventional electrode sheet drying apparatus in which a moisture spray nozzle is installed in an oven.

[0035] Figure 2 is an example of Figure 1 FIG. 4 is a diagram illustrating a conventional method of supplying moisture using a moisture injection nozzle.

[0036] Figure 3 is a diagram illustrating the problems of the conventional moisture supply method.

[0037] Figure 4 is a block diagram of an electrode sheet drying apparatus according to an exemplary embodiment.

[0038] Figure 5 is a block diagram of a solvent supply unit according to an exemplary embodiment.

[0039] Figure 6 is a diagram of an electrode sheet drying apparatus according to an exemplary embodiment.

[0040] Figure 7 is a partially enlarged view of an electrode sheet drying device according to an exemplary embodiment.

[0041] Figure 8 is a diagram of a solvent supply unit according to an exemplary embodiment.

[0042] Fig. 9 yes Figure 8 to illustrate valve operation according to an exemplary embodiment.

[0043] Fig.10 It is a figure for demonstrating the effect of this invention.

[0044] Fig.11 is a diagram of a solvent supply unit according to another exemplary embodiment.

[0045] Fig.12 is a flowchart illustrating a method of drying an electrode sheet according to an exemplary embodiment.

[0046] [reference number]

[0047] 10: Electrode sheet

[0048] 11: Uncoated part

[0049] 12: Coating part

[0050] 100: Drying device

[0051] 30, 110: Oven

[0052] 120: Solvent supply unit

[0053] 130: Hot air supply section

[0054] 130': Drying tools

[0055] 21, 121: Solvent spray nozzle

[0056] 122: Storage tank

[0057] 123: Main flow path

[0058] 124: Sub-flow path

[0059] 125: Valve

[0060] 126: Pump DETAILED DESCRIPTION

[0061] Hereinafter, the present invention will be described in detail. Prior to this, the terms and words used in this specification and claims should not be interpreted in a limiting sense or merely in a dictionary sense, but should be interpreted according to the meaning and concept consistent with the technical spirit of the present invention based on the principle that the inventor has the right to define the terms in a manner that best describes the present invention.

[0062] The terms "include", "comprising" and "having" are used herein to specify the presence of characteristics, numbers, steps, actions, parts or components, or a combination thereof, described in the specification, and it should be understood that the possibility of the presence or addition of one or more other characteristics, numbers, steps, actions, parts, components, or a combination thereof is not precluded.

[0063] In addition, when a portion of a layer, film, region or plate is disposed "on" another portion, this includes not only a case where one portion is disposed "directly" "on" another portion, but also a case where a third portion is interposed therebetween. Conversely, when a portion of a layer, film, region or plate is disposed "under" another portion, this includes not only a case where one portion is disposed "directly" "under" another portion, but also a case where a third portion is interposed therebetween. In addition, in the present application, "on" may include not only a case where it is disposed on an upper portion, but also a case where it is disposed on a lower portion.

[0064] In this specification, the X direction corresponds to a direction in which the electrode sheet is conveyed, the Y direction corresponds to a width direction of the electrode sheet, and the Z direction corresponds to a direction perpendicular to the plane of the electrode sheet or a hot air jetting direction.

[0065] In the present invention, the coated portion refers to a region of the electrode sheet to which the electrode slurry is applied, and the uncoated portion refers to a region to which the electrode slurry is not applied and to which the current collector is exposed.

[0066] Electrode sheet drying device

[0067] [First embodiment]

[0068] Figure 4 is a block diagram of an electrode sheet drying apparatus according to an exemplary embodiment, and Figure 5 is a block diagram of a solvent supply unit according to an exemplary embodiment.

[0069] Reference Figure 4 , a drying device (100, hereinafter referred to as "drying device") for an electrode sheet may include an oven 110, a solvent supply unit 120, and a drying tool 130'. According to an embodiment, the solvent supply unit 120 may be configured to block solvent supply to some of the plurality of solvent spray nozzles in response to a coating shape change of the electrode sheet.

[0070] Reference Figure 5 , the solvent supply unit 120 according to the exemplary embodiment may include a solvent injection nozzle 121, a storage tank 122, a main flow path 123, a sub-flow path 124, a valve 125, and a pump 126. In the exemplary embodiment, the valve 125 may be operated by switch control to connect and block the main flow path, and prevent the supply of solvent to some solvent injection nozzles that do not need solvent supply among the plurality of solvent injection nozzles 121 sequentially passing through the main flow path.

[0071] Such a solvent supply unit 120 can prevent the solvent from being supplied to the solvent spray nozzles located on the top side of the coating portion where spraying is not required, and thus there is no need to change the design of the solvent supply unit according to the electrode coating shape.

[0072] Figure 6 is a diagram of an electrode sheet drying apparatus according to an exemplary embodiment.

[0073] Reference Figure 6 The oven 110 constitutes the main frame of the electrode drying device 100 and is equipped with an inner space 112 for drying. There is an inlet 111 on one side of the oven 110, through which the electrode sheet 10 to be dried is introduced, and there may be an outlet 113 on the other side, through which the dried electrode sheet 10 may be discharged.

[0074] The drying device 100 may include a conveying portion that unidirectionally conveys the electrode sheet 10 to be dried through the inner space 112 via the inlet 111 and the outlet 113. The conveying portion may move the electrode sheet 10 in one direction using a plurality of unidirectionally rotating conveying rollers 140 powered by a motor (not shown).

[0075] Reference Figure 4 and Figure 6, the drying device 100 may include a drying tool 130'. The drying tool 130' is not limited as long as it is any tool capable of supplying heat energy to the electrode slurry to remove the solvent from the electrode slurry and dry it.

[0076] According to an exemplary embodiment, the drying tool 130 ′ may include a hot air supply unit 130 and / or a heater. Figure 6 An exemplary embodiment in which the hot air supply unit 130 is employed as the drying tool 130 ′ is illustrated.

[0077] According to an exemplary embodiment, the hot air supply unit 130 serves to dry the electrode slurry on the electrode sheet 10 by directing hot air toward the conveyed electrode sheet.

[0078] Specifically, the hot air supply unit 130 may include an upper trunk 131 in which a hot air supply passage is provided and a lower trunk 132, which is spaced apart from the upper trunk 131 so that the electrode sheet 10 to be dried is unidirectionally conveyed therebetween. On opposite sides of the upper trunk 131 and the lower trunk 132, hot air spray nozzles 131a, 132a may be installed, in which discharge holes capable of supplying hot air toward the electrode sheet 10 to be dried are formed. The hot air spray nozzles 131a, 132a may be installed on the upper portion of the electrode sheet 10 traveling in the oven 110, or may be installed on the upper portion and the lower portion, respectively.

[0079] According to an exemplary embodiment, the hot air supplied to the inner space 111 of the oven 110 may be a flow structure in which some of the hot air is circulated after being used to dry the electrode sheet 10 and the remaining hot air is exhausted to the outside.

[0080] According to an exemplary embodiment, the hot air supply unit 130 includes: a heat exchanger (not shown) for heating the supplied external air; hot air injection nozzles 131a, 132a, which are installed in the oven 110 and are configured to blow hot air toward the electrode sheet 10; a blower fan (not shown) for supplying the external air heated by the heat exchanger to the hot air injection nozzles 131a, 132a using a pipe connected to the internal space of the oven 110; and a damper (not shown) installed in the pipe (not shown) for adjusting the amount of the supplied hot air.

[0081] Figure 7 is a partially enlarged view of an electrode sheet drying device according to an exemplary embodiment, Figure 8 is a diagram of a solvent supply unit according to an exemplary embodiment, Fig. 9 yes Figure 8to illustrate the operation of the valve according to an exemplary embodiment, and Fig.10 It is a figure for demonstrating the effect of this invention.

[0082] The solvent supply unit 120 may be configured to spray the solvent onto the electrode sheet 10 traveling within the oven 110 .

[0083] Reference Figure 5 and Figure 7 , the solvent supply unit 120 according to the exemplary embodiment may include a solvent spray nozzle 121 , a storage tank 122 , a main flow path 123 , a sub flow path 124 , a valve 125 , and a pump 126 .

[0084] According to an exemplary embodiment, the solvent spray nozzle 121 may be formed with one or more through holes through which the solvent may be sprayed. The solvent spray nozzle 121 may be installed in the inner space 111 of the oven 110, and more specifically, the solvent spray nozzle 121 may be installed on an outer surface of the upper trunk 131 of the hot air supply unit 130 that is opposite to the lower trunk 132. However, the embodiment is not limited thereto as long as the structure can spray the solvent toward the electrode sheet 10.

[0085] According to an exemplary embodiment, a plurality (N) of solvent spray nozzles 121 may be disposed along the width direction (TD, Y direction) of the electrode sheet, and each of the N solvent spray nozzles 121 may be spaced apart from each other. Here, N refers to an integer of 2 or more, and may be in the range of 2 to 50, more particularly in the range of 2 to 30, or in the range of 3 to 10, but is not limited thereto.

[0086] Since the plurality of solvent spray nozzles 121 are spaced apart, it has the effect of spraying the solvent toward the plurality of uncoated portions of the electrode sheet in a coating pattern in which the coated portion and the uncoated portion are alternately formed along the width direction TD of the electrode sheet. In this case, the number N of the solvent spray nozzles 121 may be the same as the number of uncoated portions appearing along the width direction TD of the electrode sheet 10.

[0087] According to one embodiment, a plurality of solvent injection nozzles 121 may be provided not only along the width direction (TD, Y direction) of the electrode sheet, but also along the traveling direction (MD, X direction) of the electrode sheet. The oven 110 may include two or more drying zones, which are physically or conceptually separated along the traveling direction MD of the electrode sheet 10, wherein the drying zone at the rear end is a zone where the drying is almost completed and overdrying is relatively unlikely to occur. Therefore, the solvent injection nozzle 121 may be installed only in the rear end drying zone, or alternatively, in the middle drying zone and the rear end drying zone. However, without limitation thereto, the solvent injection nozzle 121 may be installed in all of the front drying zone, the middle drying zone, and the rear drying zone, but each of the solvent injection nozzles may be configured to be independently controllable so that the solvent is only controlled to be injected from the solvent injection nozzle 121 installed in the drying zone where the solvent injection is required.

[0088] If the solvent spray nozzles are installed in M ​​rows along the traveling direction MD of the electrode sheet, the solvent spray nozzles may be arranged in an N×M matrix in the oven 110 .

[0089] According to one embodiment, the storage tank 122 may be configured to store the solvent to be supplied to the plurality of solvent spray nozzles 121. The storage tank 122 may have a storage space formed therein for storing the solvent.

[0090] In one embodiment, the type of solvent supplied to the solvent injection nozzle is not particularly limited as long as it can be removed by the heat of drying without causing a chemical reaction with the current collector of the uncoated portion or the electrode slurry around it during the drying process. Specific examples of such solvents include water, alcohol, a solvent for the electrode slurry, an organic solvent for the electrolyte solution, etc., and water may be preferred for environmental protection purposes.

[0091] According to one embodiment, the main flow path 123 serves as a delivery pipe that supplies the solvent supplied from the storage tank 122 to the N solvent spray nozzles 121 .

[0092] According to one embodiment, the main flow path 123 is connected to the storage tank 122 , and may be configured to sequentially pass through the N solvent spray nozzles 121 .

[0093] According to this embodiment, the solvent is supplied from one storage tank 122 to the N solvent spray nozzles 121 using one main flow path, which has the advantage of simplifying the design of the solvent supply unit and reducing the space occupied by it.

[0094] According to one embodiment, the sub-flow path 124 serves as a bypass for blocking the supply of solvent through the main flow path 123 for a portion of the solvent injection nozzle 121. In some embodiments, one sub-flow path 124 is configured to bypass one solvent injection nozzle 121. Thus, the supply of solvent can be controlled to prevent the solvent from being supplied to the solvent injection nozzle that does not need it.

[0095] According to one embodiment, the sub-flow path 124 may be configured to branch from the main flow path 123 and then merge into the main flow path 123. Therefore, the solvent introduced into the sub-flow path 124 may flow back into the main flow path 123 at the merging point where the sub-flow path 124 and the main flow path 123 merge.

[0096] According to one embodiment, the valve 125 is located at a branch point between the main flow path 123 and the sub-flow path 124, and can be configured to connect and block the main flow path 123. When the valve 125 blocks the main flow path 123, the solvent supplied through the main flow path 123 flows into the sub-flow path 124 at the branch point.

[0097] On the contrary, in the closed state of the valve 125, the main flow path 123 is connected, so the solvent supplied through the main flow path 123 can enter the main flow path 123 at the branch point. In addition, the valve 125 does not connect or block the sub-flow path 124, so regardless of the opening and closing state of the valve 125, the solvent can be supplied to the sub-flow path 124.

[0098] According to one embodiment, the number of valves 125 may correspond to the number of sub-flow paths 124. That is, the number of valves 125 may be the same as the number of sub-flow paths 124. This is because the valve 125 has a function of blocking the main flow path 123 to allow the solvent to flow into the sub-flow path 124, and it is understood that the number of valves 125 is required to correspond to the number of sub-flow paths 124.

[0099] Reference Figure 8 and Fig. 9 In one embodiment, there may be three solvent injection nozzles 121a, 121b, 121c spaced apart along the width direction (Y direction) of the electrode sheet. For ease of description, the leftmost solvent injection nozzle will be referred to as the first solvent injection nozzle 121a, the central solvent injection nozzle will be referred to as the second solvent injection nozzle 121b, and the rightmost solvent injection nozzle will be referred to as the third solvent injection nozzle 121c.

[0100] In an exemplary embodiment, one sub-flow path 124 may be configured to bypass one solvent spray nozzle 121 b . Also, the valve 125 may be located at or near a branch point between the main flow path 123 and the sub-flow path 124 .

[0101] Fig. 9 (a) shows the solvent flow (arrows) when valve 125 is open, and Fig. 9 (b) shows the solvent flow (arrows) when valve 125 is in a closed state. Fig. 9 This is explained. When the valve 125 in the open state blocks the main flow path 123, the solvent flows into the sub-flow path 124 at the branch point, and the solvent is not supplied to the main flow path through the branch point and the solvent is not supplied to the next branch point. When the valve 125 in the closed state connects the main flow path 123, the solvent flows into the main flow path 123 and the sub-flow path 124.

[0102] Therefore, in the closed state of the valve 125, the solvent can be sequentially supplied to the first solvent injection nozzle 121a, the second solvent injection nozzle 121b, and the third solvent injection nozzle 121c through the main flow path 123. And, when the valve 125 is operated to the open state to stop the solvent supply to the second solvent injection nozzle 121b, the main flow path is blocked at the branch point, and the solvent supplied through the main flow path 123 flows into the sub-flow path 124 without supplying the solvent to the second solvent injection nozzle 121b. In addition, since the sub-flow path 124 branches off from the main flow path 123 and then merges into the main flow path 123, the solvent introduced into the sub-flow path 124 can enter the main flow path 123 after the sub-flow path 124 merges into the confluence point in the main flow path 123, and can be supplied to the third solvent injection nozzle 121c located downstream thereof.

[0103] As such, the sub flow path 123 may function as a bypass to prevent the solvent from being supplied to the second solvent jetting nozzle by the operation of the valve 125 .

[0104] According to one embodiment, the solvent supply unit 120 may further include a valve controller for controlling an on-off operation of the valve 125 .

[0105] According to one embodiment, the first solvent ejection nozzle disposed at the outermost side on one side of the electrode sheet width direction (TD) and the second solvent ejection nozzle disposed at the outermost side on the other side may be configured to supply the solvent only through the main flow path.

[0106] Reference Figure 8 This is described in detail. Figure 8In the embodiment, for the first solvent ejection nozzle 121a disposed at one outermost edge in the electrode sheet width direction and the third solvent ejection nozzle 121c disposed at the other outermost edge in the electrode sheet width direction, there is no sub-flow path bypassing them.

[0107] This design is based on the fact that it is not necessary to control whether to supply solvent to the first solvent ejection nozzle disposed at the outermost portion on one side in the electrode sheet width direction and the second solvent ejection nozzle disposed at the outermost portion on the other side in the electrode sheet width direction.

[0108] In other words, the first solvent jetting nozzle 121a located at the outermost portion on one side and the third solvent jetting nozzle 121c located at the outermost portion on the other side jet the solvent into the uncoated portions at both edges in the width direction (Y direction) of the electrode sheet, and since it is common to form uncoated portions at both edges in the width direction of the electrode sheet, the first solvent jetting nozzle 121a and the third solvent jetting nozzle 121c generally need to jet the solvent all the time. Therefore, there is no need to control the solvent supply of the solvent jetting nozzles located at the two outermost portions for this general shape of the electrode sheet.

[0109] However, this description is for a general electrode sheet, and if the coating form of the electrode sheet is changed, the solvent supply even to the solvent jet nozzle located at the outermost portion can be controlled by installing the sub-flow paths and valves as described above.

[0110] According to one embodiment, the solvent supply unit 120 may be configured to independently control whether to supply the solvent to each solvent spray nozzle.

[0111] Therefore, when the supply is Figure 1 When the electrode sheet is coated in a form in which the coated portion 12 and the uncoated portion 11 appear alternately along the width direction (TD, Y direction), the solvent spray nozzle disposed on the upper side of the uncoated portion 11 can spray the solvent onto the uncoated portion. Fig.10 When the electrode sheet 10 is supplied in the form of forming the uncoated portion 11 only on both edges in the width direction of the electrode sheet as shown in FIG, the solvent is not supplied to the solvent spray nozzles 121b to 121d located on the upper side of the coating portion 12 by the switching operation of the valve, and can be diverted to the sub-flow path. As described above, the drying device according to the present invention has the following effect: the solvent can be sprayed onto the uncoated portion in response to the electrode sheets having various coating forms.

[0112] The pump 126 is used to supply the solvent stored in the storage tank 122 to the solvent injection nozzle 121 via the main flow path 123. The pump 126 may be installed in the storage tank 122, or the pump 126 may be installed outside the storage tank 122. The pump may be configured to pump the solvent stored in the storage tank and supply the solvent to the main flow path 123.

[0113] [Second embodiment]

[0114] Fig.11 A solvent supply unit according to another exemplary embodiment of the present invention is illustrated.

[0115] Reference Fig.11 There may be four solvent spray nozzles spaced apart along the width direction (Y direction) of the electrode sheet. For ease of description, the four solvent spray nozzles will be referred to as the first solvent spray nozzle to the fourth solvent spray nozzle 221a, 221b, 221c, 221d from the leftmost to the rightmost.

[0116] For the remaining solvent injection nozzles (i.e., the second solvent injection nozzle 221b and the third solvent injection nozzle 221c) except the first solvent injection nozzle and the fourth solvent injection nozzle located at the outermost parts on either side of the electrode sheet width direction (Y direction), the sub-flow paths 224a, 224b bypassing them can each branch from the main flow path 223.

[0117] As the number of solvent injection nozzles increases, it is desirable to have more than one sub-flow path in order to independently control the solvent supply to each of the solvent injection nozzles. Also, since there are more than two sub-flow paths, there may be more than two valves at the branching point of the main flow path and the sub-flow path.

[0118] For ease of description, Fig.11 In the figure, the two sub-flow paths 224a and 224b will be referred to as the first sub-flow path 224a and the second sub-flow path 224b from the leftmost side to the rightmost side, and the valve located at the branch point of the first sub-flow path 224a will be referred to as the first valve 225a, and the valve located at the branch point of the second sub-flow path 224b will be referred to as the second valve 225b.

[0119] Reference Fig.11 In the path of the main flow path 223, the first sub-flow path 224a can branch between the first solvent injection nozzle 221a and the second solvent injection nozzle 221b, and in the path of the main flow path 223, the second sub-flow path 224b can branch between the second solvent injection nozzle 221b and the third solvent injection nozzle 221c.

[0120] In the path of the main flow path 223, the first sub-flow path 224a can rejoin the main flow path 223 upstream of the branch point of the second sub-flow path 224b, and the second sub-flow path 224b can rejoin the main flow path 223 between the third solvent injection nozzle 221c and the fourth solvent injection nozzle 221d.

[0121] Therefore, to control the supply of solvent to each of the plurality of solvent jetting nozzles, each of the sub-flow paths 224a, 224b is preferably configured to bypass one solvent jetting nozzle respectively.

[0122] The number of valves corresponds to the number of sub-flow paths, so that if there is more than one sub-flow path, there may also be more than one valve. If there is more than one valve, each valve may be configured to independently control the switching operation.

[0123] As a result, the on-off operation of each of the plurality of valves can be independently controlled, thereby enabling control of the supply of the solvent to the solvent jetting nozzle through the main flow path in response to the electrode sheets of different coating types.

[0124] In the above embodiment, three or four solvent ejection nozzles are installed, but the number of solvent ejection nozzles is not limited. Therefore, the number of sub-flow paths is not limited to one or two, but can be increased corresponding to the number of solvent ejection nozzles.

[0125] Furthermore, if the number of solvent jet nozzles is N, up to N-2 sub-flow paths may be installed.

[0126] Drying method of electrode sheet

[0127] Fig.12 is a flowchart for illustrating a method for drying an electrode sheet (hereinafter referred to as a “drying method”) according to an exemplary embodiment.

[0128] Now refer to Figures 8 to 12 According to an exemplary embodiment, the drying method includes a process P100 of placing an electrode sheet in an oven and inputting position information of an uncoated portion to which a solvent will not be sprayed; a valve operation process P200 of operating a valve located at a branching point between a main flow path passing through a plurality of N solvent spray nozzles arranged along a width direction (TD) of the electrode sheet and a sub-flow path branched from the main flow path based on the input information; and a solvent is supplied and the solvent is sprayed through the solvent spray nozzle P300.

[0129] The drying method according to some exemplary embodiments may utilize the above-described drying device 100. For example, the drying method according to the present invention may utilize a drying device for an electrode sheet, the drying device comprising: an oven 110 in which an internal space is formed to dry an electrode sheet in which an electrode slurry has been applied to a current collector; a solvent supply unit 120 configured to spray a solvent onto the electrode sheet traveling in the oven, wherein the solvent supply unit comprises: N solvent spray nozzles 121 installed in the oven and arranged in a plurality along the width direction (TD) of the electrode sheet, spraying the solvent toward an uncoated portion of the electrode sheet; a storage tank 122 in which a solvent to be supplied to the solvent spray nozzle is stored; a main flow path 123 connected to the storage tank and sequentially passing through the N solvent spray nozzles; at least one sub-flow path 124 branching from the main flow path and rejoining the main flow path; and a valve 125 located at a branch point between the main flow path and the sub-flow path, thereby connecting and blocking the main flow path. The drying device, the oven, the solvent spray nozzle, the main flow path, the sub-flow path, and the valve have been previously described in detail, so that repetition will be omitted.

[0130] The drying method according to one embodiment may be configured to allow control of solvent supply to at least one solvent spray nozzle via valve operation.

Claims

1. An electrode sheet drying device, the electrode sheet drying device comprising: an oven formed with an inner space for drying an electrode sheet on which an electrode slurry is coated on a current collector; as well as a solvent supply unit configured to spray a solvent onto the electrode sheet traveling in the oven, Wherein, the solvent supply unit comprises: N solvent spray nozzles, which are installed in the oven, are arranged in a plurality along the width direction TD of the electrode sheet, and spray the solvent toward an uncoated portion of the electrode sheet; a storage tank storing the solvent to be supplied to the solvent jet nozzle; a main flow path connected to the storage tank and sequentially passing through the N solvent injection nozzles; one or more sub-flow paths that branch off from the main flow path and merge back into the main flow path; and A valve is provided at a branch point between the main flow path and the sub-flow path, and connects and blocks the main flow path.

2. The electrode sheet drying device according to claim 1, in, The valve blocks the main flow path in an open state to allow the solvent to flow into the sub-flow path, and the valve connects the main flow path in a closed state to allow the solvent to flow into the main flow path.

3. The electrode sheet drying device according to claim 1, in, The number of the valves corresponds to the number of the sub-flow paths.

4. The electrode sheet drying device according to claim 1, in, The number of the sub-flow paths is two or more.

5. The electrode sheet drying device according to claim 4, in, The number of the sub-flow paths is N-2 or less.

6. The electrode sheet drying device according to claim 1, in, A sub-flow path is configured to bypass a solvent injection nozzle.

7. The electrode sheet drying device according to claim 4, in, There are two or more valves, and each valve is configured to be independently controllable to perform switching operations.

8. The electrode sheet drying device according to claim 3 or claim 4, in, The first solvent ejection nozzle disposed at one outermost portion in the electrode sheet width direction TD and the Nth solvent ejection nozzle disposed at the other outermost portion in the electrode sheet width direction TD are configured to be supplied with the solvent only through the main flow path.

9. The electrode sheet drying device according to claim 1, in, The solvent supply unit also includes: A pump is provided for supplying the solvent stored in the storage tank to the solvent spray nozzle via a main flow path.

10. The electrode sheet drying device according to claim 1, in, The solvent spray nozzle is provided in plural numbers along the traveling direction MD of the electrode sheet.

11. The electrode sheet drying device according to claim 1, further comprising: a hot air supply unit for supplying hot air to the electrode sheet traveling in the oven, Wherein, the hot air supply unit comprises: a heat exchanger that heats the supplied outside air; a hot air injection nozzle, the hot air injection nozzle being installed in the oven, the hot air injection nozzle being configured to blow hot air toward the electrode sheet; a blower fan for supplying external air heated by the heat exchanger to the hot air spray nozzle through a duct connected to an inner space of the oven; and A damper is installed in the duct to regulate the hot air supply.

12. A method for drying an electrode sheet, the method comprising the following steps: placing the electrode sheet in an oven and inputting position information of an uncoated portion to which a solvent will not be sprayed; a valve operation process of operating a valve located at a branch point of a main flow path and a sub-flow path branched from the main flow path, the main flow path passing through N solvent ejection nozzles provided in plural along a width direction TD of the electrode sheet, based on the input information; and supplying a solvent and spraying the solvent through the solvent spray nozzle, Therein, the valve operation process enables control of the supply of solvent to at least one solvent injection nozzle.

13. The electrode sheet drying method according to claim 12, in, The valve blocks the main flow path in an open state to allow the solvent to flow into the sub-flow path, and the valve connects the main flow path in a closed state to allow the solvent to flow into the main flow path.

14. The electrode sheet drying method according to claim 12, in, The number of the sub-flow paths is two or more.

15. The electrode sheet drying method according to claim 14, in, Each of the sub-flow paths bypasses one solvent injection nozzle.

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