Drying device and drying method for electrode sheets

Abstract

A drying apparatus according to one embodiment of the present invention includes a solvent supply unit for spraying solvent onto the non-coating portion. The solvent supply unit may include a main channel passing through N solvent spray nozzles arranged in the width direction TD in sequence, sub-channels branching from the main channel, and valves located at their branching points. The valves may be configured to close the main channel and allow the solvent to flow into the sub-channels. The drying apparatus according to one embodiment of the present invention may also include a valve that diverts the solvent to the sub-channels, thereby cutting off the supply of solvent to some of the solvent spray nozzles that do not require solvent spray. This eliminates the need to change the design of the solvent supply unit depending on the electrode coating configuration.

Description

[Technical Field]

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

[0002] The present invention relates to an electrode sheet drying device and a drying method, and more particularly to an electrode sheet drying device and a drying method that are configured to be able to control whether or not to supply a solvent to a solvent spray nozzle in accordance with a change in the coating pattern of the electrode sheet. [Background technology]

[0003] Generally, a lithium secondary battery is composed of 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 the positive electrode active material and the negative electrode active material used.

[0004] The electrodes of the lithium secondary battery may be formed by coating a positive or negative electrode active material onto a current collector such as an aluminum or copper sheet, mesh, film, or foil, and then drying the coated material in a drying oven.

[0005] The electrode sheet transferred to the drying oven and fed may include a coated portion coated with electrode slurry and an uncoated portion uncoated with electrode slurry. During the drying process, the solvent in the electrode slurry in the coated portion evaporates, causing the electrode slurry in the coated portion to shrink. The force of the electrode slurry shrinking in the coated portion during the drying process acts as stress on the current collector in the uncoated portion, potentially causing wrinkles and cracks. This phenomenon is exacerbated by the increasing hot air temperature due to the trend toward higher capacity and higher loading batteries.

[0006] Korean Patent Publication No. 10-2021-0015278 discloses a technology for injecting moisture into a drying oven to cool the temperature inside the oven and maintain a stable drying level for electrodes to be dried, in order to minimize electrode detachment and damage such as cracks caused by overdrying. However, this technology involves installing a moisture injection nozzle inside a duct and supplying moisture in the form of a mist to hot air supplied to the drying oven through the duct. Since moisture is not injected directly onto the uncoated areas, there are limitations to the occurrence of cracks in the uncoated areas. Therefore, a technology has been attempted in which moisture injection nozzles are installed inside the drying oven to inject moisture into the uncoated areas.

[0007] FIG. 1 shows a conventional electrode sheet drying device in which a moisture injection nozzle is installed inside a drying oven, FIG. 2 shows a conventional moisture supply method for supplying moisture to the moisture injection nozzle shown in FIG. 1, and FIG. 3 shows problems with the conventional moisture supply method.

[0008] Referring to these drawings, a plurality of moisture spray nozzles 21 are installed in a drying oven 30, and are spaced apart at regular intervals along the width direction (TD, Y direction) of the electrode sheet 10, and are configured to supply moisture S from above the electrode sheet 10 toward the electrode sheet 10. A main flow path 23 passes through the plurality of moisture spray nozzles 21, and a pump 26 is configured to supply a solvent stored in a storage tank (not shown) to the plurality of moisture spray nozzles 21 via the main flow path 23.

[0009] Meanwhile, when coating the electrode slurry, it is possible to coat the electrode so that coated portions 12 and uncoated portions 11 appear alternately along the width direction (Y direction) of the electrode sheet as shown in FIG. 1, or to coat the electrode so that uncoated portions 11 are located on both side edges in the width direction of the electrode sheet and coated portion 12 is located in the center as shown in FIG. 3.

[0010] However, conventional moisture supply methods are not suitable for such changes in coating configuration. That is, the coating device shown in Figure 1 is suitable for electrode sheets in which coated and uncoated areas 12 and 11 alternate, but for electrode sheets in which uncoated areas 11 are located only on the side edges, as shown in Figure 3, moisture must be sprayed onto the central coated area 12, where moisture spraying is not necessary.

[0011] Therefore, there is a need for technological development of an electrode sheet drying device and drying method that can solve these problems. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Korean Patent Publication No. 10-2021-0015278 Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention aims to provide an electrode sheet drying device and drying method including a solvent supply unit that can block the supply of solvent to some of a plurality of solvent spray nozzles in accordance with changes in the coating form of the electrode sheet. [Means for solving the problem]

[0014] According to one embodiment of the present invention, there is provided an electrode sheet drying device including: a drying oven having an internal space for drying an electrode sheet formed by applying an electrode slurry onto a current collector; and a solvent supply unit configured to spray a solvent onto the electrode sheet moving within the drying oven.

[0015] According to one embodiment, the solvent supply unit may include: N solvent spray nozzles that are installed in the drying oven and arranged in a plurality of positions along the width direction TD of the electrode sheet and spray solvent toward uncoated portions of the electrode sheet; a storage tank that stores the solvent to be supplied to the solvent spray nozzles; a main channel that is connected to the storage tank and passes through the N solvent spray nozzles in sequence; one or more sub-channels that branch off from the main channel and join back with the main channel; and a valve that is located at a branch point between the main channel and the sub-channels and opens and closes the main channel.

[0016] According to one embodiment, the valve may close the main channel in an on state, allowing the solvent to flow into the sub-channel, and open the main channel in an off state, allowing the solvent to flow into the main channel.

[0017] According to one embodiment, the number of valves may correspond to the number of sub-channels.

[0018] According to one embodiment, there may be two or more sub-channels.

[0019] According to one embodiment, there may be N-2 or fewer sub-channels.

[0020] According to one embodiment, one sub-channel may be configured to bypass one solvent injection nozzle.

[0021] According to one embodiment, there are two or more valves, and each valve may be configured to be independently controllable in on-off operation.

[0022] According to one embodiment, the first solvent spray nozzle arranged at the outermost position on one side of the electrode sheet in the width direction TD and the Nth solvent spray nozzle arranged at the outermost position on the other side of the electrode sheet in the width direction TD may be configured to supply the solvent only through the main flow path.

[0023] According to an embodiment, the solvent supply unit may further include a pump that supplies the solvent stored in the storage tank to the solvent injection nozzle through the main flow path.

[0024] According to one embodiment, a plurality of the solvent injection nozzles can be arranged along the moving direction MD of the electrode sheet.

[0025] A drying apparatus according to one embodiment may further include a hot air supply unit for supplying hot air to the electrode sheet moving within the drying oven, and the hot air supply unit may include a heat exchanger that heats the supplied outside air, a hot air spray nozzle that is installed within the drying oven and configured to spray hot air toward the electrode sheet, a blower fan that supplies the outside air heated by the heat exchanger to the hot air spray nozzle via a duct connected to the interior space of the drying oven, and a damper that is installed within the duct and adjusts the amount of hot air supplied.

[0026] According to another embodiment of the present invention, there is provided a method for drying an electrode sheet, including: a step of placing an electrode sheet in a drying oven and inputting position information of an uncoated portion where a solvent is not to be sprayed; a valve operating step of operating a main channel passing through N solvent spray nozzles arranged along a width direction TD of the electrode sheet and valves located at branch points of sub-channels branching from the main channel based on the input information; and a step of supplying a solvent and spraying the solvent through the solvent spray nozzles.

[0027] In the drying method according to one embodiment, the supply of solvent to at least one solvent injection nozzle can be controlled through the valve operation process.

[0028] In one embodiment, the valve may close the main channel in an on state, allowing the solvent to flow into the sub-channel, and open the main channel in an off state, allowing the solvent to flow into the main channel.

[0029] In one embodiment, there may be two or more sub-channels.

[0030] In one embodiment, each sub-channel can be configured to bypass one solvent injection nozzle. [Effects of the Invention]

[0031] In a drying apparatus according to an embodiment of the present invention, the solvent supplied to the solvent spray nozzles via the main flow path can be diverted to the sub-flow path, and the solvent supply to some of the solvent spray nozzles that do not require solvent spraying can be blocked, thereby eliminating the need to change the design of the solvent supply unit depending on the coating form of the electrode sheet. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a view showing a conventional electrode sheet drying apparatus in which a moisture spray nozzle is installed inside a drying oven. [Figure 2] 2 is a diagram showing a conventional method for supplying water to the water injection nozzle shown in FIG. 1. [Figure 3] 1 is a diagram for explaining problems with a conventional moisture supply method. [Figure 4] FIG. 2 is a block diagram of an electrode sheet drying device according to one embodiment. [Figure 5] FIG. 2 is a block diagram of a solvent supply unit according to one embodiment. [Figure 6] 1 is a diagram of an electrode sheet drying device according to an embodiment. [Figure 7] FIG. 2 is a partially enlarged view of the electrode sheet drying device according to the embodiment. [Figure 8] 1 is a diagram of a solvent supply unit according to one embodiment. [Figure 9] 9 is an enlarged view of a portion of FIG. 8 for explaining the operation of a valve according to an embodiment. [Figure 10] 1 is a diagram for explaining the effects of the present invention. [Figure 11] 10 is a diagram of a solvent supply unit according to another embodiment. [Figure 12]1 is a flowchart illustrating a method for drying an electrode sheet according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention will be described in detail below. Before that, the terms and words used in the specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concepts of the terms in order to best describe his own invention.

[0034] As used throughout the present specification, terms such as "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and may be understood as not precluding the presence or possible addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0035] Furthermore, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion therebetween. Conversely, when a layer, film, region, plate, or other portion is described as being "under" another portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion therebetween. Furthermore, in the specification of the present invention, being "located on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0036] In this specification, the X direction corresponds to the direction in which the electrode sheet is transported, the Y direction corresponds to the width direction of the electrode sheet, and the Z direction corresponds to the direction perpendicular to the plane of the electrode sheet or the direction in which hot air is sprayed.

[0037] In the present invention, the coated portion refers to a region of the electrode sheet where electrode slurry is applied, and the uncoated portion refers to a region where electrode slurry is not applied and where the current collector is exposed.

[0038] <Electrode sheet drying device>

[0039] (First embodiment) FIG. 4 is a block diagram of an electrode sheet drying device according to one embodiment, and FIG. 5 is a block diagram of a solvent supply unit according to one embodiment.

[0040] 4, an electrode sheet drying apparatus 100 (hereinafter referred to as the "drying apparatus") may include a drying oven 110, a solvent supply unit 120, and a drying means 130'. According to one embodiment, the solvent supply unit 120 may be configured to be able to cut off the solvent supply to some of a plurality of solvent spray nozzles in response to changes in the coating form of the electrode sheet.

[0041] 5, the solvent supply unit 120 according to one embodiment may include a solvent injection nozzle 121, a storage tank 122, a main channel 123, a sub-channel 124, a valve 125, and a pump 126. In an exemplary embodiment, the valve 125 closes the main channel by an on-off operation, thereby cutting off the supply of solvent to some of the solvent injection nozzles 121 that do not require solvent supply, among the plurality of solvent injection nozzles 121 that sequentially pass through the main channel.

[0042] Such a solvent supply unit 120 can block the supply of solvent to the solvent injection nozzle located above the grounded area where solvent injection is not required, which has the advantage that the design of the solvent supply unit does not need to be changed depending on the type of electrode coating.

[0043] FIG. 6 is a diagram of an electrode sheet drying device according to one embodiment.

[0044] 6, the drying oven 110 constitutes the main frame of the electrode drying apparatus 100 and has an internal space 112 for drying therein. The drying oven 110 may have an inlet 111 at one side thereof through which the electrode sheet 10 to be dried is inserted, and an outlet 113 at the other side thereof through which the electrode sheet 10 that has been dried can be discharged.

[0045] The drying device 100 may include a transport unit that transports the electrode sheet 10 to be dried in one direction so that the electrode sheet 10 passes through the internal space 112 via the inlet 111 and the outlet 113. The transport unit may transport the electrode sheet 10 to be dried in one direction using a plurality of transport rollers 140 that are rotated in one direction by receiving power from a motor (not shown).

[0046] 4 and 6, the drying apparatus 100 may include a drying means 130′. The drying means 130′ is not limited as long as it is a means that can supply thermal energy to the electrode slurry and remove the solvent in the electrode slurry to dry the electrode slurry.

[0047] According to one embodiment, the drying means 130' may include a hot air supply unit 130 or / and a heater. Figure 6 shows an embodiment in which a hot air supply unit 130 is adopted as the drying means 130'.

[0048] According to one embodiment, the hot air supply unit 130 sprays hot air toward the transported electrode sheet 10 to dry the electrode slurry on the electrode sheet.

[0049] Specifically, the hot air supply unit 130 may include an upper trunk 131 having a hot air supply passage therein, and a lower trunk 132 spaced apart from the upper trunk 131 so that the electrode sheet 10 to be dried is transported in one direction between the upper trunk 131. Hot air spray nozzles 131a and 132a having outlet holes for supplying hot air toward the electrode sheet 10 to be dried may be installed on opposing surfaces of the upper trunk 131 and the lower trunk 132. The hot air spray nozzles 131a and 132a may be installed above the electrode sheet 10 moving within the drying oven 110, or may be installed at the top and bottom, respectively.

[0050] According to one embodiment, the hot air supplied to the inner space 112 of the drying oven 110 may have a flow structure in which a portion of the hot air is circulated after being used to dry the electrode sheet 10, and the remaining portion is exhausted to the outside.

[0051] According to one embodiment, the hot air supply unit 130 may include a heat exchanger (not shown) that heats the supplied outside air, hot air spray nozzles 131a, 132a that are installed in the drying oven 110 and configured to spray hot air toward the electrode sheet 10, a blower fan (not shown) that supplies the outside air heated by the heat exchanger to the hot air spray nozzles 131a, 132a through a duct connected to the internal space of the drying oven 110, and a damper (not shown) that is installed in the duct (not shown) and adjusts the amount of hot air supplied.

[0052] FIG. 7 is a partially enlarged view of an electrode sheet drying device according to one embodiment, FIG. 8 is a diagram of a solvent supply unit according to one embodiment, FIG. 9 is a partially enlarged view of FIG. 8 to explain the operation of a valve according to one embodiment, and FIG. 10 is a diagram to explain the effects of the present invention.

[0053] The solvent supply unit 120 may be configured to spray a solvent onto the electrode sheet 10 moving within the drying oven 110 .

[0054] 5 and 7, a solvent supply unit 120 according to an embodiment may include a solvent injection nozzle 121, a storage tank 122, a main channel 123, a sub-channel 124, a valve 125, and a pump 126.

[0055] According to one embodiment, the solvent spray nozzle 121 may have one or more through-holes formed therein through which the solvent can be sprayed. The solvent spray nozzle 121 may be installed in the interior space 112 of the drying oven 110, and more specifically, may be installed on an outer surface of the upper trunk 131 of the hot air supply unit 130 that faces the lower trunk 132. However, the embodiment is not limited thereto as long as the structure is capable of spraying the solvent toward the electrode sheet 10.

[0056] According to one embodiment, a plurality (N) of solvent spray nozzles 121 may be arranged along the width direction (TD, Y direction) of the electrode sheet, and the N solvent spray nozzles 121 may be spaced apart from each other. Here, N represents an integer of 2 or more, and may be, but is not limited to, a number ranging from 2 to 50, more particularly from 2 to 30, or from 3 to 10.

[0057] The solvent spray nozzles 121 are spaced apart from one another, so that the solvent can be sprayed toward the plurality of uncoated portions of the pattern-coated electrode sheet in a manner that alternates between coated and uncoated portions along the width direction TD of the electrode sheet 10. In this case, the number N of the solvent spray nozzles 121 may be the same as the number of uncoated portions along the width direction TD of the electrode sheet 10.

[0058] According to one embodiment, a plurality of solvent injection nozzles 121 may be arranged not only in the width direction (TD, Y direction) but also along the movement direction (MD, X direction) of the electrode sheet. The drying oven 110 may be physically or conceptually divided into two or more drying zones along the movement direction MD of the electrode sheet 10. The rear drying zone is a section where drying is almost complete and is relatively more likely to occur overdrying. On the other hand, the front drying zone is a section where drying is in the early stages and is relatively less likely to occur overdrying. Therefore, the solvent injection nozzles 121 may be installed only in the rear drying zone or only in the middle and rear drying zones. However, this is not limited thereto. The solvent injection nozzles 121 may be installed in all of the front, middle, and rear drying zones, and each solvent injection nozzle may be configured to be independently controllable, so that solvent is injected only from the solvent injection nozzles 121 installed in the drying zone where solvent injection is required.

[0059] If the solvent spray nozzles are installed in M ​​rows along the moving direction MD of the electrode sheet, the solvent spray nozzles may be arranged in the drying oven 110 in an N×M matrix.

[0060] According to an 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.

[0061] In one embodiment, the solvent supplied to the solvent spray nozzle is not particularly limited as long as it does not chemically react with the current collector in the uncoated area or the electrode slurry therearound during the drying process and can be removed by drying heat. Specific examples of such solvents include water, alcohol, solvents for the electrode slurry, and organic solvents for the electrolyte solution, with water being preferred for environmental friendliness.

[0062] According to an embodiment, the main flow path 123 serves as a transfer pipe for supplying the solvent supplied from the storage tank 122 to the N solvent injection nozzles 121 .

[0063] According to an embodiment, the main flow path 123 may be connected to the storage tank 122 and may have a structure in which the N solvent injection nozzles 121 are passed through in sequence.

[0064] According to such an embodiment, the solvent is supplied to the N solvent injection nozzles 121 from one storage tank 122 via one main flow path, which has the advantage of simplifying the design of the solvent supply units and saving the space they occupy.

[0065] The sub-channels 124 according to one embodiment serve as bypass channels for blocking the supply of solvent to some of the solvent injection nozzles 121 via the main channel 123. In some embodiments, one sub-channel 124 is configured to bypass one solvent injection nozzle 121. This allows control so that solvent is not supplied to solvent injection nozzles that do not require solvent supply.

[0066] According to one embodiment, the sub-channel 124 may be structured to branch off from the main channel 123 and merge with the main channel 123 again. Thus, the solvent flowing into the sub-channel 124 may flow back into the main channel 123 at the merging point where the sub-channel 124 and the main channel 123 merge.

[0067] The valve 125 according to an embodiment is located at the branch point of the main channel 123 and the sub-channel 124 and may be configured to open or close the main channel 123. When the valve 125 closes the main channel 123, the solvent supplied through the main channel 123 flows into the sub-channel 124 at the branch point.

[0068] Conversely, when the valve 125 is in an off state, the main channel 123 is open, so that the solvent supplied through the main channel 123 can flow into the main channel 123 at the branch point. Meanwhile, the valve 125 does not open or close the sub-channel 124, so that the solvent can be supplied to the sub-channel 124 regardless of the on or off state of the valve 125.

[0069] According to one embodiment, the number of valves 125 may correspond to the number of sub-channels 124. That is, the number of valves 125 may be the same as the number of sub-channels 124. This is because the valves 125 have the function of closing the main channel 123 and allowing the solvent to flow into the sub-channels 124, and it goes without saying that the number of valves 125 required corresponds to the number of sub-channels 124.

[0070] 8 and 9, in one embodiment, three solvent injection nozzles 121a, 121b, and 121c may be installed at intervals along the width direction (Y direction) of the electrode sheet. For ease of explanation, the leftmost solvent injection nozzle will be referred to as the first solvent injection nozzle 121a, the central solvent injection nozzle as the second solvent injection nozzle 121b, and the rightmost solvent injection nozzle as the third solvent injection nozzle 121c.

[0071] In an exemplary embodiment, one sub-channel 124 may be configured to bypass one solvent injection nozzle 121b, and the valve 125 may be located at or near the branch point of the main channel 123 and the sub-channel 124.

[0072] 9(a) shows the flow of solvent (arrows) when the valve 125 is in the on state, and FIG. 9(b) shows the flow of solvent (arrows) when the valve 125 is in the off state. The following will be explained with reference to FIG. 9. When the valve 125 is in the on state and closes the main channel 123, the solvent flows into the sub-channel 124 at the branch point and is no longer supplied to the main channel between the branch point and the next branch point. When the valve 125 is in the off state and opens the main channel 123, the solvent flows into the main channel 123 and the sub-channel 124.

[0073] As a result, when the valve 125 is in an off state, 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 via the main channel 123. When the valve 125 is turned on to stop the solvent supply to the second solvent injection nozzle 121b, the main channel is closed at the branch point, the solvent supplied via the main channel 123 flows into the sub-channel 124, and the solvent is no longer supplied to the second solvent injection nozzle 121b. Meanwhile, since the sub-channel 124 branches off from the main channel 123 and merges with the main channel 123 again, the solvent that has flowed into the sub-channel 124 flows into the main channel 123 after the merge point where the sub-channel 124 and the main channel 123 merge again, and can be supplied to the third solvent injection nozzle 121c located downstream of the merge point.

[0074] In this way, the sub-channel 124 can serve as a detour to prevent the solvent from being supplied to the second solvent jet nozzle 121b by the operation of the valve 125.

[0075] The solvent supply unit 120 according to one embodiment may further include a valve controller for controlling the on-off operation of the valve 125 .

[0076] According to one embodiment, the first solvent spray nozzle arranged at the outermost position on one side in the width direction TD of the electrode sheet and the Nth solvent spray nozzle arranged at the outermost position on the other side may be configured to supply the solvent only through the main flow path.

[0077] This will be described with reference to Fig. 8. According to the embodiment of Fig. 8, there are no sub-flow paths bypassing the first solvent spray nozzle 121a arranged at the outermost position on one side in the width direction of the electrode sheet and the third solvent spray nozzle 121c arranged at the outermost position on the other side in the width direction of the electrode sheet.

[0078] This is a design that does not require control of whether or not solvent is supplied to the first solvent spray nozzle located at the outermost edge on one side of the electrode sheet in the width direction, and the Nth solvent spray nozzle located at the outermost edge on the other side of the electrode sheet in the width direction.

[0079] That is, the first solvent spray nozzle 121a located at the outermost position on one side and the third solvent spray nozzle 121c located at the outermost position on the other side spray solvent onto the uncoated areas on both side edges in the width direction (Y direction) of the electrode sheet, but because uncoated areas are generally formed on both side edges in the width direction of the electrode sheet, the first solvent spray nozzle 121a and the third solvent spray nozzle 121c generally need to spray solvent all the time. Therefore, in such a general electrode sheet, it is not necessary to control whether or not the solvent is supplied to the solvent spray nozzles located at the outermost positions on both sides.

[0080] However, this is a description that applies to a general type of electrode sheet, and if the coating type of the electrode sheet is changed, it is of course possible to control whether or not to supply solvent even to the solvent injection nozzle located at the outermost periphery through the installation of the sub-channels and valves as described above.

[0081] The solvent supply unit 120 according to one embodiment may be configured to be able to independently control whether or not to supply solvent to each solvent injection nozzle.

[0082] As a result, when an electrode sheet is supplied that is coated so that coated portions 12 and uncoated portions 11 alternate along the width direction (TD, Y direction) as shown in Fig. 1, the solvent spray nozzles located above the uncoated portions 11 can spray solvent onto the uncoated portions. Also, when an electrode sheet 10 is supplied that has uncoated portions 11 formed only on both side edges in the width direction of the electrode sheet as shown in Fig. 10, the on-off operation of the valves can prevent solvent from being supplied to the solvent spray nozzles 121b-121d located above the coated portions 12, and the solvent can be diverted to the sub-channels. As described above, the drying apparatus according to the present invention has the effect of being able to spray solvent onto the uncoated portions in accordance with electrode sheets having various coating patterns.

[0083] The pump 126 serves to supply the solvent stored in the storage tank 122 to the solvent injection nozzle 121 through the main flow path 123. The pump 126 may be installed inside the storage tank 122 or outside the storage tank 122. The pump may be configured to pump up the solvent stored in the storage tank and supply it to the main flow path 123.

[0084] (Second embodiment) FIG. 11 shows a solvent supply unit according to another embodiment of the present invention.

[0085] 11, four solvent injection nozzles may be installed at intervals along the width direction (Y direction) of the electrode sheet. For ease of explanation, the four solvent injection nozzles will be referred to as first to fourth solvent injection nozzles 221a, 221b, 221c, and 221d in order from the leftmost to the rightmost.

[0086] For the second solvent injection nozzle 221b and the third solvent injection nozzle 221c, which are the remaining solvent injection nozzles excluding the first solvent injection nozzle and the fourth solvent injection nozzle located at the outermost sides in the width direction (Y direction) of the electrode sheet, sub-flow paths 224a and 224b that bypass these nozzles, respectively, can branch off from the main flow path 223.

[0087] As the number of solvent injection nozzles increases, it is preferable to provide two or more sub-channels in order to independently control whether or not solvent is supplied to each of the solvent injection nozzles. In addition, since there are two or more sub-channels, there may also be two or more valves located at the branch points of the main channel and the sub-channels.

[0088] For ease of explanation, in FIG. 11, the two sub-flow paths 224a and 224b are referred to as the first sub-flow path 224a and the second sub-flow path 224b, respectively, starting from the leftmost one, and the valve located at the branching point of the first sub-flow path 224a is referred to as the first valve 225a, and the valve located at the branching point of the second sub-flow path 224b is referred to as the second valve 225b.

[0089] Referring to FIG. 11, a first sub-channel 224a may branch off from the path of the main channel 223 between the first solvent injection nozzle 221a and the second solvent injection nozzle 221b, and a second sub-channel 224b may branch off from the path of the main channel 223 between the second solvent injection nozzle 221b and the third solvent injection nozzle 221c.

[0090] The first sub-channel 224a may merge with the main channel 223 again upstream of the branch point of the second sub-channel 224b in the path of the main channel 223, and the second sub-channel 224b may merge with the main channel 223 again between the third solvent injection nozzle 221c and the fourth solvent injection nozzle 221d in the path of the main channel 223.

[0091] In this way, in order to control whether or not solvent is supplied to each of the plurality of solvent injection nozzles, each of the sub-flow paths 224a, 224b is preferably configured to bypass one solvent injection nozzle.

[0092] The number of valves corresponds to the number of sub-channels, so if there are two or more sub-channels, there may be two or more valves. If there are two or more valves, each valve may be configured to be independently controllable for on-off operation.

[0093] This allows the on / off operation of each of the valves to be independently controlled, and allows the supply of solvent to the solvent spray nozzle via the main flow path to be controlled in accordance with electrode sheets having various coating forms.

[0094] In the above embodiment, three or four solvent injection nozzles are installed, but the number of solvent injection nozzles is not limited to this. Accordingly, the number of sub-channels is not limited to one or two, and can be increased corresponding to the number of solvent injection nozzles.

[0095] On the other hand, when the number of solvent injection nozzles is N, a maximum of N-2 sub-channels can be installed.

[0096] <How to dry the electrode sheet>

[0097] FIG. 12 is a flowchart illustrating a method for drying an electrode sheet according to one embodiment (hereinafter referred to as the "drying method").

[0098] 8 to 12, a drying method according to one embodiment may include a step (P100) of placing an electrode sheet in a drying oven and inputting position information of an uncoated portion where a solvent is not to be sprayed; a valve operation step (P200) of operating a main channel passing through N solvent spray nozzles arranged along a width direction TD of the electrode sheet and valves located at branch points of sub-channels branching from the main channel based on the input information; and a step (P300) of supplying a solvent and spraying the solvent through the solvent spray nozzles.

[0099] A drying method according to some embodiments may use the drying apparatus 100 described above. For example, the drying method according to the present invention may use an electrode sheet drying apparatus including: a drying oven 110 having an internal space for drying an electrode sheet in which electrode slurry is applied to a current collector; and a solvent supply unit 120 configured to spray a solvent onto an electrode sheet moving within the drying oven. The solvent supply unit is installed in the drying oven and includes N solvent spray nozzles 121 arranged along the width direction TD of the electrode sheet and spraying the solvent toward uncoated portions of the electrode sheet; a storage tank 122 for storing the solvent to be supplied to the solvent spray nozzles; a main channel 123 connected to the storage tank and passing sequentially through the N solvent spray nozzles; one or more sub-channels 124 branching from the main channel and joining the main channel again; and a valve 125 located at the branch point of the main channel and the sub-channels for opening and closing the main channel. The drying apparatus, the drying oven, the solvent spray nozzles, the main channel, the sub-channels, and the valve have been described in detail above, so repeated description will be omitted.

[0100] The drying method according to one embodiment may be configured so that the supply of solvent to at least one solvent injection nozzle can be controlled through the valve operation process. [Explanation of symbols]

[0101] 10: Electrode sheet 11: Plain area 12:Landed area 100:Drying equipment 30, 110: Drying oven 120: Solvent supply unit 130: Hot air supply unit 130':Drying means 21, 121: Solvent injection nozzle 122: Storage tank 123: Main channel 124: Sub-channel 125: Valve 126: Pump

Claims

1. a drying oven having an internal space for drying the electrode sheet formed by applying the electrode slurry onto the current collector; a solvent supply unit configured to spray a solvent onto the electrode sheet moving within the drying oven; The solvent supply unit comprises: N solvent spray nozzles are installed in the drying oven and arranged along the width direction of the electrode sheet, spraying a solvent toward the uncoated portion of the electrode sheet; a storage tank for storing the solvent to be supplied to the solvent injection nozzle; a main flow path connected to the storage tank and passing through the N solvent injection nozzles in sequence; one or more sub-channels branching from the main channel and rejoining the main channel; a valve located at a branch point of the main flow path and the sub-flow path, for opening and closing the main flow path.

2. The electrode sheet drying device according to claim 1 , wherein the valve closes the main flow path in an on state to allow the solvent to flow into the sub-flow path, and opens the main flow path in an off state to allow the solvent to flow into the main flow path.

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

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

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

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

7. The electrode sheet drying device according to claim 4, wherein the number of the valves is two or more, and each valve is configured to be capable of being independently controlled to be turned on and off.

8. The electrode sheet drying device according to any one of claims 1 to 7, wherein the first solvent spray nozzle arranged at the outermost position on one side in the width direction of the electrode sheet and the Nth solvent spray nozzle arranged at the outermost position on the other side in the width direction of the electrode sheet are configured to supply the solvent only via the main flow path.

9. The solvent supply unit comprises: The electrode sheet drying device according to claim 1 , further comprising a pump that supplies the solvent stored in the storage tank to the solvent spray nozzle through a main flow path.

10. The electrode sheet drying device according to claim 1 , wherein a plurality of the solvent spray nozzles are arranged along the moving direction of the electrode sheet.

11. a hot air supply unit for supplying hot air to the electrode sheet moving in the drying oven; The hot air supply unit is a heat exchanger for heating the supplied outside air; a hot air injection nozzle installed in the drying oven and configured to inject hot air toward the electrode sheet; a blower fan that supplies the outside air heated by the heat exchanger to a hot air injection nozzle through a duct connected to the interior space of the drying oven; The electrode sheet drying device according to claim 1 , further comprising: a damper installed in the duct to adjust the amount of hot air supplied.

12. a step of putting the electrode sheet into a drying oven and inputting the position information of the plain area where the solvent is not sprayed; a valve operation step of operating a main flow path passing through N solvent injection nozzles arranged in a width direction of the electrode sheet and valves located at branch points of sub-flow paths branching from the main flow path based on the input information; supplying a solvent and injecting the solvent through the solvent injection nozzle; The method for drying an electrode sheet, wherein the supply of solvent to at least one solvent spray nozzle can be controlled through the valve operation process.

13. The method for drying an electrode sheet according to claim 12 , wherein the valve closes the main flow path in an on state to allow the solvent to flow into the sub-flow path, and opens the main flow path in an off state to allow the solvent to flow into the main flow path.

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

15. The method for drying an electrode sheet according to any one of claims 12 to 14, wherein each of the sub-flow paths bypasses one solvent injection nozzle.

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