Electrode sheet drying device and electrode sheet drying method using the same

Abstract

According to an exemplary embodiment of the present invention, an electrode sheet drying device includes a drying oven, multiple spray nozzles disposed within the drying oven, a flow path configured to guide water to the multiple spray nozzles, and a pump capable of moving water through the flow path, and the flow path may include one or more PTC heaters therein. The PTC heater may heat the water sprayed onto the electrode sheet, thereby supplying water at a temperature above a certain level to the electrode sheet. The water sprayed onto the electrode sheet may prevent cracks and wrinkles from occurring in non-coated areas, improving the stability of the electrode.

Description

[Technical Field]

[0001] The present invention relates to an electrode sheet drying device and an electrode sheet drying method using the same, and more particularly to an electrode sheet drying device that can prevent defects and improve electrode stability, and an electrode sheet drying method using the same.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0074575, filed June 12, 2023, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Secondary batteries can be charged and discharged multiple times and are used as energy sources for various electronic devices. Electrodes for lithium secondary batteries can be formed by a drying process of drying an electrode sheet, and the drying process can be performed using a drying device including a drying oven.

[0004] An electrode sheet can be formed by coating an electrode slurry containing an active material onto a current collector such as aluminum (Al), copper (Cu), or foil. The electrode sheet can include a coated area where the electrode slurry is applied and an uncoated area where the electrode slurry is not applied. During the drying process, the solvent in the electrode slurry in the coated area evaporates, causing the electrode slurry in the coated area to shrink. The force of the electrode slurry shrinking in the coated area during the drying process acts as stress on the uncoated area of ​​the current collector, potentially causing electrode defects such as wrinkles and cracks. Therefore, research is needed to develop technologies that can improve electrode safety. Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, the problem to be solved by the technical idea of ​​the present invention is to provide an electrode sheet drying device with improved electrode stability and an electrode sheet drying method using the same. [Means for solving the problem]

[0006] According to an exemplary embodiment of the present invention to solve the above-mentioned problems, there is provided an electrode sheet drying device. According to some embodiments, the electrode sheet drying device includes: a drying oven capable of drying an electrode sheet formed by applying a slurry onto an electrode current collector; a plurality of spray nozzles disposed within the drying oven, the spray nozzles being arranged along the width direction of the electrode sheet and configured to spray water onto the electrode sheet; a flow path configured to guide the water to the plurality of spray nozzles; and a pump capable of moving the water through the flow path, wherein the flow path may include one or more PTC (Positive Temperature Coefficient) heaters therein.

[0007] According to an exemplary embodiment of the present invention, there is provided a method for drying an electrode sheet, the method including the steps of: a pump supplying water to a flow path having an inlet and an outlet; a first temperature sensor measuring the temperature of the water flowing into the inlet; a controller determining whether a PTC heater needs to be operated based on the water temperature; turning on the PTC heater included in the flow path when the controller determines that the PTC heater needs to be operated; and spraying the water, whose temperature has been increased by the PTC heater, onto the electrode sheet from a plurality of spray nozzles connected to the outlets of the flow path, wherein the temperature of the water sprayed from the plurality of spray nozzles may be in the range of 50°C to 90°C. [Effects of the Invention]

[0008] An electrode drying device according to an exemplary embodiment of the present invention includes a plurality of spray nozzles for spraying water onto an electrode sheet, and a flow path including a PTC heater therein. The PTC heater heats the water sprayed onto the electrode sheet, thereby supplying water at a certain temperature or higher to the electrode sheet. The water sprayed onto the electrode sheet can prevent cracks and wrinkles from occurring in non-coated areas, thereby improving the stability of the electrode.

[0009] The effects that can be obtained from the exemplary embodiments of the present disclosure are not limited to the effects described above, and other effects not mentioned can be clearly derived and understood by a person having ordinary skill in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects accompanying the implementation of the exemplary embodiments of the present disclosure can also be derived from the exemplary embodiments of the present disclosure by a person having ordinary skill in the art. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating an electrode sheet drying device according to an exemplary embodiment. [Figure 2] 1 is a diagram illustrating an electrode sheet in a drying oven according to an exemplary embodiment. [Figure 3] 1 is a diagram illustrating an electrode sheet drying device according to an exemplary embodiment. [Figure 4] 1 is a cross-sectional perspective view of a flow channel including a PTC heater according to an exemplary embodiment. [Figure 5] FIG. 10 is a cross-sectional perspective view of a flow channel including a PTC heater according to another exemplary embodiment. [Figure 6] 10 is a view showing an electrode sheet drying device according to another exemplary embodiment. [Figure 7] 1 is a flowchart illustrating a method for drying an electrode sheet according to an exemplary embodiment. [Figure 8] 10 is a flowchart illustrating a method for drying an electrode sheet according to another exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] According to an exemplary embodiment of the present invention to solve the above-mentioned problems, an electrode sheet drying device is provided. According to some embodiments, the electrode sheet drying device includes: a drying oven capable of drying an electrode sheet formed by applying a slurry onto an electrode current collector; a plurality of spray nozzles disposed within the drying oven and arranged along the width direction of the electrode sheet and configured to spray water onto the electrode sheet; a flow path configured to guide the water to the plurality of spray nozzles; and a pump capable of moving the water through the flow path, wherein the flow path may include one or more PTC heaters therein.

[0012] In some embodiments, the flow path includes a plurality of PTC heaters extending along the extension direction of the flow path, and the plurality of PTC heaters may be arranged at equal intervals in the circumferential direction of the flow path.

[0013] According to some embodiments, the length of each of the plurality of PTC heaters is in the range of 20% to 80% of the total length of the flow path.

[0014] In some embodiments, the flow path includes a plurality of PTC heaters, and the plurality of PTC heaters may be spaced apart along the elongated direction of the flow path.

[0015] In some embodiments, the flow path may have a double pipe configuration including an inner pipe and an outer pipe surrounding the inner pipe, and the PTC heater may be located between the inner pipe and the outer pipe.

[0016] In some embodiments, the flow channel may include a plurality of inwardly projecting thermally conductive blades.

[0017] In some embodiments, the electrode sheet drying device further includes a control unit, the pump includes a first temperature sensor (thermistor sensor), and the control unit can adjust the operation of the PTC heater based on the temperature of the water measured by the first temperature sensor.

[0018] In some embodiments, the system may further include a first temperature sensor and a second temperature sensor, where the first temperature sensor is configured to measure the temperature of water flowing into the flow path and the second temperature sensor is configured to measure the temperature of water heated by the PTC heater downstream of the PTC heater.

[0019] According to some embodiments, a first temperature sensor may be included in the pump and a second temperature sensor may be included in the flow path.

[0020] According to some embodiments, the first temperature sensor and the second temperature sensor may be included in a PTC heater.

[0021] In some embodiments, the electrode sheet drying device further includes a control unit, and the control unit can determine whether to activate the PTC heater based on the temperature of the water detected by the first temperature sensor and the second temperature sensor.

[0022] According to some embodiments, the water sprayed onto the electrode sheet may have a temperature in the range of 50°C to 90°C.

[0023] According to some embodiments, the electrode sheet drying device may further include a storage tank storing water to be supplied to the plurality of spray nozzles, and the flow path may further include a flow rate control unit.

[0024] To solve the above-mentioned problems, an exemplary embodiment of the present invention provides a method for drying an electrode sheet, including the steps of: a pump supplying water to a flow path having an inlet and an outlet; a first temperature sensor measuring the temperature of the water flowing into the inlet; a controller determining whether a PTC heater needs to be operated based on the water temperature; turning on the PTC heater included in the flow path when the controller determines that the PTC heater needs to be operated; and spraying the water whose temperature has been increased by the PTC heater onto the electrode sheet from multiple spray nozzles connected to the outlets of the flow path, where the temperature of the water sprayed from the multiple spray nozzles can be in the range of 50°C to 90°C.

[0025] According to some embodiments, the method for drying an electrode sheet further includes, after the step of activating the PTC heater, a step of measuring the temperature of the water with a second temperature sensor included in the flow path and located downstream of the PTC heater, and when the temperature of the water measured by the second temperature sensor is in the range of 70°C to 90°C, the control unit can stop (off) the operation of the PTC heater.

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. As a premise, the terms and words used in this 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 an inventor can appropriately define the concept of terms in order to best describe his or her invention.

[0027] Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and therefore there may be various equivalents and modifications that can replace them at the time of this application.

[0028] Furthermore, in the description of the present invention, if it is determined that a detailed description of related publicly known structures or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0029] The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and therefore the shapes and sizes of components in the drawings may be exaggerated, omitted, or shown in a schematic manner for clearer explanation. Therefore, the sizes and proportions of each component do not completely reflect the actual sizes and proportions.

[0030] <Electrode sheet drying device> (First embodiment) FIG. 1 is a diagram showing an electrode sheet drying device according to an exemplary embodiment.

[0031] FIG. 2 is a diagram illustrating an electrode sheet in a drying oven according to an exemplary embodiment.

[0032] FIG. 3 is a diagram illustrating an electrode sheet drying device according to an exemplary embodiment.

[0033] 1 to 3, the electrode sheet drying apparatus 100 may include a drying oven 101, a hot air supplying device 102, a flow path 110, a plurality of spray nozzles 120, a pump 130, and a storage tank 160. The electrode sheet drying apparatus 100 may be configured to dry the electrode sheet 200 moving within the drying oven 101 with hot air supplied from the hot air supplying device 102. The hot air supplying device 102 is drying means. The drying means is not limited as long as it is means for supplying thermal energy to the electrode sheet 200 to dry the electrode sheet 200.

[0034] The electrode sheet 200 may be formed by applying a slurry 201 onto a current collector 202. The electrode sheet 200 may include a coated portion where the slurry 201 is applied onto the current collector 202, and a non-coated portion where the slurry 201 is not applied onto the current collector 202.

[0035] The electrode sheet drying apparatus 100 may provide water transferred via a flow path 110 to a moving electrode sheet 200. The flow path 110 may include an inlet 110_1 through which water flows in and an outlet 110_2 through which water flows out. A plurality of spray nozzles 120 may be disposed in the drying oven 101 and may spray water onto the moving electrode sheet 200. According to an exemplary embodiment, the plurality of spray nozzles 120 may be disposed along the width direction of the electrode sheet 200. The plurality of spray nozzles 120 may be connected to the outlet 110_2 of the flow path 110, and the water transferred via the flow path 110 may be sprayed onto the electrode sheet 200 through the plurality of spray nozzles 120. According to an exemplary embodiment, the water may be sprayed onto an uncoated portion of the electrode sheet 200.

[0036] The pump 130 may provide the power that may move the water through the flow path 110. The pump 130 may be located inside the storage tank 160 or outside the storage tank 160.

[0037] FIG. 4 is a cross-sectional perspective view of a flow channel including a PTC heater according to an exemplary embodiment.

[0038] FIG. 5 is a cross-sectional perspective view illustrating a flow channel including a PTC heater according to another exemplary embodiment.

[0039] 4 and 5, the flow path 110 may include one or more PTC heaters 113 therein. The PTC heaters 113 may be electric heating elements using PTC thermistors. A PTC thermistor is a resistor whose resistance changes sensitively in response to temperature changes. For example, as the temperature increases, the resistance increases, thereby restricting the flow of current. This makes it easy for the PTC heaters 113 to heat water to a uniform temperature.

[0040] The PTC heater 113 can prevent the temperature of the water moving in the flow path 110 from changing due to the external environment. As a result, the electrode sheet drying device 100 can provide water having a certain temperature range to the electrode sheet 200. In addition, using the PTC heater 113 to heat the water moving through the flow path 110 can shorten the time required for heating compared to heating all of the water contained in the storage tank 160.

[0041] The flow path 110 may have a double-pipe configuration including an inner pipe 111 and an outer pipe 112 surrounding the inner pipe 111, and the PTC heater 113 may be located between the inner pipe 111 and the outer pipe 112. The inner pipe 111 may be configured to transfer heat emitted from the PTC heater 113 to water moving within the flow path 110. The inner pipe 111 may include a thermally conductive material. The outer pipe 112 may be configured to insulate the PTC heater 113 from external temperatures. Furthermore, the outer pipe 112 may be configured to prevent heat emitted by the PTC heater 113 from escaping to the outside. According to an exemplary embodiment, the thickness of the inner pipe 111 may be thinner than the thickness of the outer pipe 112. Therefore, the double-pipe configuration of the flow path 110 may improve the efficiency of the PTC heater 113.

[0042] According to an exemplary embodiment, the flow path 110 may include a plurality of PTC heaters 113 extending along the extension direction of the flow path 110, and the plurality of PTC heaters 113 may be arranged at equal intervals in the circumferential direction of the flow path 110. According to an exemplary embodiment, the plurality of PTC heaters 113 may be arranged at regular intervals along the extension direction of the flow path 110. In this way, the plurality of PTC heaters 113 are provided at equal intervals within the flow path 110, and can heat water uniformly without surrounding the entire inner pipe 111.

[0043] According to an exemplary embodiment, the length of each of the multiple PTC heaters 113 may be in the range of approximately 20% to 80% of the entire length of the flow path 110. According to an exemplary embodiment, the length of each of the multiple PTC heaters 113 may be in the range of approximately 30% to 70% of the entire length of the flow path 110. The PTC heaters 113 are characterized by rapid heating, and the multiple PTC heaters 113 may be disposed at equal intervals within the flow path 110. This allows water to be heated uniformly and quickly even if the length of each of the multiple PTC heaters 113 is shorter than the entire length of the flow path 110. Furthermore, the reduction in the area occupied by the PTC heaters 113 within the flow path 110 may also improve energy efficiency.

[0044] According to an exemplary embodiment, the flow path 110 may further include a plurality of thermally conductive blades 114 protruding inward. The plurality of thermally conductive blades 114 may be arranged at equal intervals along the circumferential direction of the flow path 110. The plurality of thermally conductive blades 114 may be arranged at equal intervals along the extension direction of the flow path 110. This allows the plurality of thermally conductive blades 114 to quickly transfer heat generated by the plurality of PTC heaters 113 to the water.

[0045] According to an exemplary embodiment, the plurality of thermally conductive blades 114 may have a shape in which their thickness decreases along the inner direction of the flow path 110. This may prevent the mobility of water in the flow path 110 from being hindered. The extension shape of the plurality of thermally conductive blades 114 may be a linear extension shape as shown in FIG. 5 or a curved extension shape.

[0046] There are no significant limitations on the material of the thermally conductive blades 114, as long as the material is capable of transmitting thermal energy. For example, the thermally conductive blades 114 may include a metal. According to an exemplary embodiment, the thermally conductive blades 114 may include aluminum, copper, iron, tungsten, nickel, and alloys containing one or more of these.

[0047] According to an exemplary embodiment, the water supplied to the electrode sheet 200 by the multiple spray nozzles 120 may have a temperature in the range of about 50°C to about 90°C. According to an exemplary embodiment, the water supplied to the electrode sheet 200 by the multiple spray nozzles 120 may have a temperature in the range of about 70°C to about 90°C. According to an exemplary embodiment, the water supplied to the electrode sheet 200 may be in a liquid state. Because the water is in a liquid state, it is easy to spray the water toward the non-coated portions of the electrode sheet 200 and can prevent the water from being sprayed toward the coated portions. This can prevent cracks and wrinkles from occurring in the non-coated portions, reducing electrode defects and improving electrode stability.

[0048] (Second embodiment) FIG. 6 is a diagram showing an electrode sheet drying device according to another exemplary embodiment.

[0049] According to an exemplary embodiment, the electrode sheet drying apparatus 100 may further include a control unit 150 and a first temperature sensor 140_1. According to an exemplary embodiment, the electrode sheet drying apparatus 100 may further include a control unit 150, a first temperature sensor 140_1, and a second temperature sensor 140_2.

[0050] The first temperature sensor 140_1 may measure the temperature of water flowing into the flow path 110. The second temperature sensor 140_2 may measure the temperature of water heated by the PTC heater 113 downstream of the PTC heater 113. Whether to activate the PTC heater 113 may be determined based on the temperatures of the water measured by the first temperature sensor 140_1 and the second temperature sensor 140_2. According to an exemplary embodiment, the first temperature sensor 140_1 may be included in the pump 130, and the second temperature sensor 140_2 may be included in the flow path 110. According to an exemplary embodiment, the first temperature sensor 140_1 and the second temperature sensor 140_2 may be included in the PTC heater 113. For example, a PTC thermistor may include the first temperature sensor 140_1 and the second temperature sensor 140_2.

[0051] The control unit 150 may determine whether to activate the PTC heater 113 based on the water temperature measured by the first temperature sensor 140_1 and the second temperature sensor 140_2. If the water temperature detected by the first temperature sensor 140_1 is lower than a set temperature, the control unit 150 may activate the PTC heater 113. The set temperature may be in the range of approximately 50°C to 70°C.

[0052] The second temperature sensor 140_2 may be located downstream of the PTC heater 113 and may measure the temperature of the heated water. The control unit 150 may stop the operation of the PTC heater 113 when the temperature of the water measured by the second temperature sensor 140_2 is in the range of about 70°C to about 90°C. This allows the temperature of the water to be maintained within a certain temperature range.

[0053] According to an exemplary embodiment, the electrode sheet drying apparatus 100 may further include a storage tank 160 and a flow rate regulator 170. The storage tank 160 may provide a place for the water to be stored before being transferred to the flow path 110. The flow rate regulator 170 may measure the flow rate and flow rate of the water. Based on the data detected by the flow rate regulator 170, the strength of the pump 130 may be adjusted.

[0054] <How to dry the electrode sheet> (First embodiment) FIG. 7 is a flowchart showing the method for drying the electrode sheet according to the first embodiment.

[0055] 3, 6, and 7, the method for drying an electrode sheet may include step P110 in which a pump 130 supplies water to a flow path 110 having an inlet 110_1 and an outlet 110_2, step P120 in which a first temperature sensor 140_1 measures the temperature of the water flowing into the inlet 110_1, step P130 in which a control unit 150 determines whether or not the PTC heater 113 needs to be operated based on the water temperature, and step P140 in which the control unit 150 turns on the PTC heater 113 included in the flow path 110 when it determines that the PTC heater 113 needs to be operated. According to an exemplary embodiment, the method for drying an electrode sheet may further include the step of spraying the water, the temperature of which has been increased by the PTC heater 113, onto the electrode sheet 200 from a plurality of spray nozzles 120 connected to the outlet 110_2 of the flow path 110, and the temperature of the water sprayed from the plurality of spray nozzles 120 may be in the range of approximately 50°C to 90°C. According to an exemplary embodiment, the temperature of the water sprayed from the plurality of spray nozzles 120 may range from approximately 70°C to 90°C.

[0056] Step P110 in which the pump 130 supplies water to the flow path 110 having the inlet 110_1 and the outlet 110_2 may be a step in which water stored in the storage tank 160 flows into the inlet 110_1 of the flow path 110. The flow rate adjuster 170 disposed in the flow path 110 may detect the flow rate and flow rate of the water flowing into the flow path 110.

[0057] The step in which the control unit 150 determines whether the PTC heater 113 needs to be activated based on the water temperature may be a step of checking whether the temperature of the water flowing into the inlet 110_1 is below a set temperature. The set temperature is a temperature that determines whether the PTC heater 113 should be activated, and may be in a range of approximately 50°C to 70°C. According to an exemplary embodiment, when the water temperature is below approximately 50°C, the control unit 150 may determine that the PTC heater 113 needs to be activated. According to an exemplary embodiment, when the water temperature is below approximately 60°C, the control unit 150 may determine that the PTC heater 113 needs to be activated.

[0058] Meanwhile, if the control unit 150 determines that operation of the PTC heater 113 is not necessary, the method for drying the electrode sheet may further include step P150 of stopping the operation of the PTC heater 113. Alternatively, if the PTC heater 113 is not in operation, the control unit 150 may maintain the stop of the PTC heater 113. For example, if the temperature of the water flowing into the flow path 110 is about 50°C or higher, the PTC heater 113 may not operate.

[0059] (Second embodiment) FIG. 8 is a flowchart showing a method for drying an electrode sheet according to the second embodiment.

[0060] 3, 6, and 8, the method for drying an electrode sheet may further include, after the step of activating the PTC heater 113, step P160 in which a second temperature sensor 140_2 located downstream of the PTC heater 113 measures the temperature of the water, and step P170 in which the control unit 150 determines whether or not to activate the PTC heater 113 based on the water temperature. The second temperature sensor 140_2 may be included in the flow path 110. If the temperature of the water measured by the second temperature sensor 140_2 is in the range of about 70°C to about 90°C, step P180 in which the control unit 150 stops (turns off) the operation of the PTC heater 113 may be performed. According to an exemplary embodiment, if the temperature of the water measured by the second temperature sensor 140_2 is in the range of about 80°C to about 90°C, step P180 in which the control unit 150 stops (turns off) the operation of the PTC heater 113 may be performed.

[0061] On the other hand, if the control unit 150 determines that the operation of the PTC heater 113 is not necessary, the method for drying the electrode sheet may further include step P190 of maintaining the operation of the PTC heater 113. For example, if the temperature of the water detected by the second temperature sensor 140_2 is less than about 70°C, the control unit 150 may maintain the operation of the PTC heater 113. [Explanation of symbols]

[0062] 100: Electrode sheet drying device 101: Drying oven 102:Hot air supply device 110: Flow path 110_1: Inlet 110_2:Outlet 111: Internal piping 112:Outside piping 113: PTC heater 114: Thermally conductive blade 120: Injection nozzle 130: Pump 140_1: First temperature sensor 140_2: Second temperature sensor 150: Control unit 160: Storage tank 170: Flow rate adjustment section 200: Electrode sheet 201: Slurry 202: Electrode current collector

Claims

1. a drying oven for drying the electrode sheet formed by applying the slurry onto the electrode current collector; a plurality of spray nozzles disposed in the drying oven, arranged along the width direction of the electrode sheet, and configured to spray water onto the electrode sheet; a flow path configured to guide the water to the plurality of spray nozzles; a pump that moves the water through the flow path; The electrode sheet drying device, wherein the flow path includes one or more positive temperature coefficient heaters therein.

2. the flow path includes a plurality of positive temperature coefficient heaters extending along an extension direction of the flow path; The electrode sheet drying device according to claim 1 , wherein the plurality of positive temperature coefficient heaters are arranged at equal intervals in a circumferential direction of the flow channel.

3. 3. The electrode sheet drying device according to claim 2, wherein the length of each of the plurality of positive temperature coefficient heaters is in the range of 20% to 80% of the entire length of the flow path.

4. the flow path includes a plurality of positive temperature coefficient heaters; The electrode sheet drying device according to claim 1 or 2, wherein the plurality of positive temperature coefficient heaters are arranged at regular intervals along an extension direction of the flow path.

5. The flow path has a double pipe shape including an inner pipe and an outer pipe surrounding the inner pipe, The electrode sheet drying device according to claim 1 , wherein the positive temperature coefficient heater is located between the inner pipe and the outer pipe.

6. The electrode sheet drying device according to claim 1 , wherein the flow path includes a plurality of heat-conducting blades protruding inward.

7. The electrode sheet drying device further includes a control unit, the pump includes a first temperature sensor; The electrode sheet drying device according to claim 1 , wherein the control unit adjusts the operation of the positive temperature coefficient heater based on the temperature of the water measured by the first temperature sensor.

8. further comprising a first temperature sensor and a second temperature sensor; the first temperature sensor measures the temperature of the water flowing into the flow path; 4. The electrode sheet drying device according to claim 1, wherein the second temperature sensor is configured to measure the temperature of the water heated by the positive temperature coefficient heater downstream of the positive temperature coefficient heater.

9. the first temperature sensor is included in the pump; The electrode sheet drying device according to claim 8 , wherein the second temperature sensor is included in the flow path.

10. The electrode sheet drying device according to claim 8 , wherein the first temperature sensor and the second temperature sensor are included in the positive temperature coefficient heater.

11. The electrode sheet drying device further includes a control unit, 9. The electrode sheet drying device according to claim 8, wherein the control unit determines whether to operate the positive temperature coefficient heater based on the temperatures of the water detected by the first temperature sensor and the second temperature sensor.

12. The electrode sheet drying device according to claim 1 , wherein the water sprayed onto the electrode sheet has a temperature in the range of 50° C. to 90° C.

13. further comprising a storage tank in which the water to be supplied to the plurality of spray nozzles is stored; The electrode sheet drying device according to claim 1 , wherein the flow path further includes a flow rate control unit.

14. a pump supplying water to a flow path having an inlet and an outlet; a first temperature sensor measuring the temperature of the water entering the inlet; a control unit determining whether a positive temperature coefficient heater needs to be activated based on the temperature of the water; activating the positive temperature coefficient heater included in the flow path when the control unit determines that it is necessary to activate the positive temperature coefficient heater; and spraying the water, the temperature of which has been increased by the positive temperature coefficient heater, onto an electrode sheet from a plurality of spray nozzles connected to the outlets of the flow paths; The method for drying an electrode sheet, wherein the temperature of the water sprayed from the plurality of spray nozzles is in the range of 50°C to 90°C.

15. after the step of activating the positive temperature coefficient heater, a second temperature sensor included in the flow path and positioned downstream of the positive temperature coefficient heater measures the temperature of the water; The method for drying an electrode sheet according to claim 14, wherein the control unit stops operation of the positive temperature coefficient heater when the temperature of the water measured by the second temperature sensor is in a range of 70°C to 90°C.

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